Operator 1 chapter 10 Disinfection

Chlorine contact chamber

A baffled basin that provides sufficient detention time of chlorine contact with wastewater for disinfection to occur. The minimum contact time is usually 30 minutes.

Chemical feeder setting Gallons Per Day formula

Chemcial feeder setting (GPD) = Flow (MGD) X polymer Dose (mg/l) X 8.34 (lbs/gallon) / Liquid Polymer. (Lbs/gallon)

Chemtrec

Chemical Transportation Emergency Center. A public service of the American Chemistry Council dedicated to assisting emergency responders deal with incidents involving hazardous materials. Their toll-free 24-hour emergency phone number is (800) 424-9300.

Hypochlorite

Chemical compounds containing available chlorine ; used for disinfection they are available as liquids (bleach) or solids (powder granules and pellets) in barrels drumsa nd cans salts of hypochlorous acid

Chemical feed formula

Chemical feed (lbs per day) = chemical applied (pounds) / length of application (days)

Chemical feeder setting Milliliters per minute formula

Chemical feeder setting (ml/minute) = Flow (GPD) X Dose (mg/L) X 3.785 (liters/day) X 1000000(Minute) / Liquid polymer (mg/ml) X 24 (hours/ day) X 60 (minutes/hour)

Convert percent to pounds of chemical solution formula

Chemical solution (lbs/gallon) = pounds of chemical / 100 (Lbs of chemical and water)

Methods of disinfection

Chlorine Ultraviolet light Or ozone

Free chlorine state

Chlorine added to water becomes hypochlorous acid or hydrochloric acid In solutions dilute with pH above 4, hypochlorous acid is most complete and leaves little free chlorine existing, hypochlorous acid is weak acid adn very poorly broken up at pH levels below pH 6. So any free chlorine or hypochlorite added to water will form either form hypochlorous acid or hypochlorite dependent on pH of water. Hypochlorous acid has 40-80 times greater disinfection potential than hypochlorite

Free chlorine

Chlorine in liquid or gaseous form, combines with water to form hypochlorite HOCL and hydrochloric HCI acids. In wastewater, free chlorine usually combines with an amine (ammonia or nitrogen) or other organic compounds to form combined chlorine compounds

free available chlorine

chlorine available (after chlorine demand has been satisfied) in the forms of hypochlorous acid and hypochlorite ions this does not include chlorine that has been combined with ammonia nitrogen or other compounds,

Hepatitis

inflammation of the liver caused by an acute viral infection, yellow and ice is one symptom of hepatitis

Saprophytes

organisms that obtain food by absorbing dead or decaying tissues of other organisms, they help natural decomposition of organic matter in water

Chemical feed pump setting in percent formula

setting (%)= desired feed pump (GPD) X 100(%) / maximum feed pump (GPD)

Disease causing microorganisms

Bacteria viruses and parasites Called pathogenic

Contact time vs dosing

Better to give chlorine more contact time than increasing dose, more effective if contact time lengthened

Symptoms of chlorine exposure

Causes restlessness, panic, severe irritation of throat, sneezing, production of saliva, and followed by Coughing, retching, vomiting, difficulty breathing. Worse for people with asthma and chronic bronchitis, liquid chlorine causes irritation and blistering on contact with skin

Chlorine absorption solutions

Caustic soda Soda ash Hydrated lime

Routine operation tasks

Check up monitors for UV transmission routinely clean UV lamps

Chlorine feed rate formula

Chlorine feed rate (lbs/day) = Flow (MGD) X Dose (mg/L) X 8.34 (lbs/gallon)

Chlorine residual contorl

Chlorine feed rate is controlled by desired chlorine residual (usually combined available chlorine, level after mixing and reaction time, a water sample is titrated by amperometric analyzer recorder, a residual chlorine level varies above or below a desired set point level, chlorinator is caused to change its feed rate to bring chlorine residual back to desired level

Disposal of used lamps

Contact regulatory agency for proper disposal of UV lamps Do not throw lamps in garbage as tehy are hazardous mercury within the lamps

Trickling filters and chlorine

Contorls slime growths and destroys filter fly larvae Applied to produce residual of .5mg/l and no more as too much can hamper biological growths on filter media. Becomes difficult to evaluate filter performance on basis of BOD removals as chlorine will interfere with BOD test by removing some BOD by itself. Continous chlorination at trickling filters can be expensive alternative to correcting filter fly problems

System hydraulics

Erratic or reduced inactivation performance is caused by poor system hydraulics most often. System sort circuiting poor entry and exit flow conditions, and dead spaces or dead zones in reactor all can be sources of poor performance

Chlorine dioxide facility

Existing chlorination units an be used to produce chlorine in dioxide, in addition to existing chlorination system, a diaphragm pump solution tank mixer chlorine dioxide generating tower,and electrical controls are installed. Diaphragm pump and piping must be made of corrosion resistant material usually PVC or polyethylene pipe

Virus illnesses

Gastroenteritus Heart anomalies Infectious hepatitis Meningitis Poliomyelitis

in channel cleaning of UV lamps

Has problems associated with it, like Back up channel is required and a much greater volume of acid solution is needed. Additional equipment and storage tanks for chemicals are required Precautions taken to prevent damage to concrete channels from acid cleaning solution epoxy coatings normally are used to protect concrete from acid attack are not used in UV disinfection systems because epoxy breaks down under UV light intensity

Mono and dichloramine

Have definite disinfection powers and are interest in measurement of chlorine residuals Cichloramine has more effective disinfecting power tahn monochloramine

Control of chlorine flow to points of application achieved by these methods

Manual control Start stop control Step rate control Time program control Flow proportional control Chlorine residual control Compound loop control

Sulfur dioxide on human body table

Page 403

Connections at evaporator

Piping from manifold to evaporator carries liquid chlorine. Piping from evaporator to chlorinator carries chlorine gas. Evaporators normally are furnished with all necessary intermediate valves and fittings

Operational strategy for sulfonators

Same as chlorinators

total chlorine residual

The total amount of chlorine residual (including both free chlorine and chemically bound chlorine) present in a water sample after a given contact time.

Total chlorine

The total concentration of chlorine in water, including the combined chlorine (such as inorganic and organic chloramines) and the free available chlorine.

Particles shielding bacteria

These particles protect bacteria from UV disinfection process These particles should be removed by upstream treatment process like improved clarifier performance and some type of filtration

Chlorine leak procedure.

- Before new system put into service, clean dry and tested for leaks. Pipelines may be cleaned and dried by flushing and steaming from the high end to allow condensate and foreign material to drain out, or by the use fo commercially available cleaning solvents compatible with chlorine, after the empty line is heated thoroughly dry air may be blown through line until dry. After drying system may be tested with tightness with 150 PSI Leaks may be detected by application of soapy water to the outside of joints. Small quantities of chlorine gas may now be introduced into the line and test pressure built up with air, and system tested fro leaks with ammonia, when new system is tested for leaks, at least one chlorinator should be in case of a leak, the same is true of emergency leak at any installation. If chlorinator is not running, one more should be started -find small chlorine leak, tie a rag on stick and dip in ammonia, then hold rag near the suspected points, a polyethylene squeeze bottle may also be used. Care must be taken to avoid spraying ammonia water on any leak or touching cloth to metal. White fumes will indicate the exact location of leak. Location of leaks taht diffuse gas ove large areas do not use an ammonia spray bottle because the entire room could turn white if it is full of chlorine. -if leak is in the equipment in which chlorine is being used, close the valves on chlorine container at once, repair shoud not be attempt while equipment is in service. All chlorine piping and equipment that is to be repaired by welding should be flushed with water or steam. Before returning equipment to use, it must be cleaned Reid and tested as previously described. -if leak is in a chlorine cylinder, or container. Use the proper emergency repair kit, supplied by most chlorine suppliers, these kits can be used to stop most leaks in a chlorine cylinder or containers adn can usually be delivered to a plant within a few hours if one is not already at site of leak. It is advisable to have emergency repair kits available at your plant at all times and train personnel in use. Respiratory protective equipment should be located outside chlorine storage areas. The repair kids may be located withi chlorine storage areas because during an emergency requiring their use, you will be usingapproved respiratory protection and thuswill be accessable -if chlorine is escaping as a liquid from a cylinder or a ton tank, turn container so that leaking side is on top, this will only allow chlorine gas to escape. Also only 1/15 as much chlorine escapes in compared to liquid chlorine leaking. Also reduces amount of chlorine gas leaking out of container. Increase the feed rate to cool the supply tanks as much as possible -for situations in which a prolonged or unstoppable leak is encountered, emergency disposal of chlorine should be provided. Can be absorbed in caustic soda, soda ash, or agitated hydrated lime slurries. Chlorine should be passed into the solution through iron pipe or properly weighted rubber hose to keep it immersed in solution. A barometric loop or vacuum breaking device must be installed ot prevent back siphonage.container should not be immersed because leaks wil be aggravated due to corrosive effect of chlorine with water, and container may float when partially empty, and it may be advisable to move container to an isolated area. -never put water on chlorine leak as it increases rate of corrosion and make leak larger. Water may warm the chlorine thus increasing the pressure and forcing the chlorine to escape faster -leaks around valves stems can often be stopped by closing the valve or tightening the packing gland nut tighten the nut or stem by turning it sideways. -leaks at valve discharge outlet can often be stopped by replacing the gasket or adapter connection -leaks at fusible plugs and cylinder valves usually require special handling and emergency equipment. Call chlorine supplier immediately and obtain emergency repair kit for this purpose if you do not have a kit readily available -pinhole leaks in th walls of cylinder and ton tanks can be stopped by using a clamping pressure saddle with a turnbuckle available in repair kits, this is only a temporary measure, the container must be emptied as soon as possible. If repair kit not available use ingenuity. Leaking confidant must not be shipped, if container leaks or if valves do not work properly keep container until you recieve instruction. -do not accept deliver of containers howing evidence of leaking -if chlorine container develops a leak be sure your supplier does not charge you for unused chlorine -chlorine leaks may be detected by chlorine gas detection devices, alarm systems may be connected to these devices be sure to follow the manufacturers recommendations regarding frequency of checking and testing detection devices and alarms ysetms

Gas chlorinator start up

- be sure chlorine gas valve at chlorinator is closed, this valve should ahve been closed already sense chlorinator is out of service -all chlorine valves on the supply line should have been closed during shutdown Tag any valve that should remain open for any reason -inspect all tubing manifold and valve connections for potential leaks and be sure all joints are gasketed - check the chlorite solution distribution lines to be sure system properly valves to deliver chlorine solution to desired point of application -open chlorine metering orifice slightly by adjusting chlorine feed rate control -start injector water supply system, injector water is pumped at appropraite flow rate and flow through injector creates vacuum in injector taht draws in chlorine gas, chlorine absorbed and mixed into water at injector, -examine injector water supply system, note reading on pressure gauge, if it is abnormal, identify cause and correct. The should read pressure greater than 50 psi and note reading on injector vacuum gauge, and if less than normal, machine may function at a lower feed rate but will be unable to deliver maximum rated capacity -inspect chlorinator vacuum lines for leaks - crack open chlorine container valve and allow gas to enter line, inspect all joints for leaks by placing ammonia soaked rag near each joint, avoid spraying ammonia water on any leak or touching cloth to any metal, formation fo white cloud or vapor will indicate chlorine leak. Move down from valve at chlorine container to down line and check all lints between valve and next one down stream. If valves pass ammonia test, open valve and continue to next valve and if no leaks in chlorinator, open cylinder valve approximately one complete turn toobtain maximum discharge - inspect chlorinator with gas pressure ranging between 20-30 psi and contorl gas pressure by using pressure regulating valve Operate chloraintor at. Complete range to check feed rates and check operation on manual and automatic settings Chlorinator is ready for use after these steps log time placed into service and application point

Emergency repair kits types

-100 lb and 150 lb cylinders Chlorine institute emergency kit A Stops leaks at valve fusible plug and tank itself - ton tanks kit B contains equipment to stop leaks at the valve fusible plug or tank - tank cars and tank trucks kit C Stops leaks only at the valve and safety valve there are variations in valve arrangements dn cleanreances on some sulfur dioxide tank cars Ensure adequate equipment is in kit C for the emergency before it happens.

Low temp in evaporator

-Check chemical flow through rate, rate may exceeded units capacity and may require two evaporators to be on line to handle chemical (chlorine) feed rate -Inspect immersion heaters for proper operation, first examine control panel for thermal overload on breaker, most evaporators are equipped with two to three heating elements, an inspection of electrical system will indicate if breakers shorted or open and will locate problem replace any heating elements that have failed -if no spare evaporators are around, operate from the valves on chlorine gas supply, and reduce the chlorine feed rate to keep chlorination system working properly

Important points when working with chlorine facilities

-Chlorinators should be located near point of application as possible -Chlorinator room should be separate to chlorine container strange room, prevents chlorine gas leak from harming personnel or equipment -ample working space around the equipment and storage space for spare parts should be provided -should be ample supply of water to operate chlorinator at the required capacity under maximum pressure conditions at chlorinator discharge from injector - building should be adequately heated, temperature of chlorine cylinder and chlorinator should be above 50F. Line heaters may be used to keep chlorine piping and chlorinator at higher temps to prevent condensing of gas into liquid in pipelines Temp difference of 5-10F is recommended maximum temperature at which a chlorine cylinder is stored should not exceed 100F -it is not advisable to draw more than 40 pounds chlorine from any one 100 to 150 pound cylinder in 24 hour period due to danger of freezing and slowing down chlorine flow. Limit of chlorine as is about 8 pounds of chlorine per F ambient temperature where vaproatos are provided, these limitations are not applied -should have adequate lighting -there must be adequate ventilation. Removes leaking chlorine gas. Forced ventilation is preferred, exhaust ventilation should be taken from point within 12 inches, because chlorine is heavier than air. Mechanical ventilation must be at rate of not less than one cubic foot of air per minute square foot of floor are of storage space. When chlorine leak occurs, air should be vented into treatment system to remove chlorine. A caustic scrubbing sysyem can be used to treat air containing chlorine leak. Treatment system should remove chlorine concentration to 1/2 IDLH for chlorine 10 ppm. Secondary course of power is needed for chlorine detection alarm ventilation and treatment system. -chlorination rates must be checked against chlorinator setting, therefore adequate measuring and controlling chlorine dosage is required. Scales and recorders indicating loss in wieght are desireable as continous checks and as a record of continuity of chlorine and weights recorded daily. -there should be continuity of chlorine, when chloraitno is practiced for disinfection, it is needed continously to protect downstream water users. Arrange chlorination will function for 1440 minutes every day.to secure this, chlorine gas lines from cylinders should feed to manifold so that the cylinders can be removed without interrupting the feed of gas.dupicate units with automatic ctdliner switchover should be provided.

Monthly chlorinator tasks

-Exercise all chlorine valves -inspect heater and room ventilation equipment -check chlorinator vent line to outside of structure for ay obstructions that prevent fre access to atmosphere bugs and wasps like to vent lines for nest, instal fine wire mesh over open end of vent line to solve this -inspect unit for vacuum leaks -clean rotameter sight glass -inspect all drain lines and houses -perform scheduled routine maintenance like repack seta and stem valves, inspect tubing and fittings for leaks, wash and Ray thoroughly before reassembling, inspect control system electrical and electronics pneumatics lubrication ad calibration of total sysetm -check chlorine analyzer for lubrications of chart drives, filter drives, and pumps. Clean and full all piping hoses filters tubing cell blocks and hydrualic chamber -replace electrode in cell block -replace buffer pumps and system solenoids clean acid and iodide reserviors Calibrate unit with known standards and repaint unit Inspect safety equipment including self contained breathing equipment and repairs kits

Start up sequence

-Follow preliminary steps in 10.1025 -install the Uv banks if removed previously -close UV channel mud valve -open corresponding influent channel gate -return us banks to service

Hypochlorinator feed system parts and construction

-They contain some type of storage system for solution, storage container is made of corrosion resistant materials like plastic -solution piping, which is usually Fiberglass or PVC -diffusers which are made of same material as piping system -pumps which are made of corrosion resistant materials epoxy lined systems have been discussed -flowmeter constructed from hastelloy C straight through metal tube ROTAMETER with float position determined magnetically and low rate transmitted either electronically or pneumatically -chlorine residual analyzer of amperimetic type are commonly installed -automatic controls which consist of hypochlorite flow controller, recorder, and totalizer, and ratio control station and necessary elecotnric signal converter Feed system can be operated automatically or by manual control, operating hypochlorite system usually cost twice as much as a liquid chlorine system, and maintenance of hypochlorinator system requires more operator hours than do liquid chlorine system

Maintenance of supply area

-area should be kept clean and free of unused objects -all lifting devices like hand trucks and hoists should be properly maintained. A maintenance program should be stablished -ventilation system should be periodically inspected for proper operation. Be sure that fan is running when switch is on the ON position

Start up gas sulfonator

-be sure gas valve at sulfonator closed -all sulfur dioxide valves on supply line should already be closed, if any valves are required to be open for any reason, this exception must be indicated by tag -inspect all tubes along manifold and valve connections for potential leaks and be sure all joints are gasketed -check sulfur dioxide solution distribution lines that they are all properly valves to deliver sulfur dioxide solution to desired point of application -open sulfur dioxide metering orifice slightly by adjusting sulfur dioxide feed rate control - start the injector water supply system Source of water is plant effluent or potable water Supply water is pumped at appropriate flow rate and pressure through injector, which creates sufficient vacuum in injector to draw sulfur dioxide gas. Gas should be absorbed and mixed in water at the injector. The solution then conveyed to point of application -examine injector water supply system for reading on injector supply pressure gauge is normal, and reading on injector vacuum gauge is within average standards, if the reading is lower than normal the machine may be functioning at lower feed rate but wil be unable to deliver maximum rated capacity -inspect sulfonator vacuum lines for leaks -crack open sulfur dioxide container valve and allow gas to enter the line, inspect all joints. Use ammonia soaked rag near each joint to check for leaks. Do not spray ammonia water on leak or touch cloth to any metal. White cloud indicates leak. -inspect sulfonator, and see gas pressure at sulfonator is between 20-30 psi,, and contorl gas pressure by adjusting pressure reducing valve on supply line, operator sulfonator at complete range of feed rates, check operation on manual and automatic settings, use ammonia water to check all connections on sulfonator, if there are no leaks then open sulfur dioxide container valve one full turn -sulfonator is ready for use log in time the sulfonator is placed into service

Evaporator daily tasks

-check evaporator water bath to be sure water level is at midpoint of sight glass -be sure wter bath temp is between 160 and 195F low alarm should sound around 160F and high alarm at 200F -determine chlorine inlet pressure at evaporator pressure should be same as supply manifold from containers 20-100 psi -determine chlorine outlet temperature from evaporator with range of 90 to 105 high alarm is 110 and low alarm the chlorine pressure reducing valve will close due to low temp in water bath -check CPRV operation -if evaporator is equipped with water bath recirculation pump at back of evaporator, determine pump working properly -look for leaks and repair any discovered

Chlorinator including injectors daily tasks

-check injector water supply pressure 40-90 psi Determine injector vacuum range from 15-25 inches of mercury Check chlorinator vacuum valves range from 5-10 inches of mercury Determine chlorinator supply pressure ranging from 20-40 psi Read chlorinator feed rate on rotameter tube. Is feed rate at required level Record rotameter reading and time Examine and record mode of control ranging from manual, automatic single input or automatic dual input Measure chlorine residual at application point Inspect system for chlorine leaks Inspect auxiliary components by doing flow signal input, does feed rate cahnge when flow changes in chlorinator, does chlorinator resposne normally checked by biasing flow signal? Which may drive dosage control unit on chlorinator to full open or closed position, when switch is released, chlorinator will return to previous feed rate, the unit should have responded smoothly through the cahnge -if chlorinator also is controlled by residual analyzer be sure analyzer is working properly check following items -actual chlorine residual is properly indicated, recorder alarm set point, recorder control set point, sample water flow, sample water flow to cell block after dilution with fresh water, adequate flow of dilution water, filter system and drain, and cell block has buffer pump and solution feed correct, run pH test on block. And check amount of grit in cell block and add more grit if amount is low as grit is used to keep electrode free of slimes and chemcial scales in order to provide quick and accurate readings Cell block hydraulics purger. Run comparison tests of chlorine residuals, do tests match with analyzer output readings, If residual samples two streams, start other stream flow and compared tested residual of that stream with analyzer output readings, enter any changes or corrections into logs Chance recorder chart daily, date. The chart for record keeping purposes Check recorder output signal controlling chlorinator for control responses on feed rate, correct feed rates through ratio controller

Short term shut down of chlorinator

-close chlorine container gas outlet valve -allow chlorine gas to completely evacuate system through injector, zero psi on chlorien pressure gauge -close chlorinator gas discharge valve, can remain like this indefinitely and can be put back into service any time by opening this valve and chlorine gas outlet valve. Inspect chlorine leaks throughout chlorination system -shut down injector if dedicated to chlorinator being removed from service -disconnect chlorine container from system or routinely check the pressure in chlorinator because the chlorine contaienr valve may leak, also chlorinator inlet valve may be closed

Liquid sulfur dioxide hazards

-containers burst or safety devices activate if liquid is overpressurized or excessively heated Violent chemical reactions result if water is drawn back into the chemical in containers -body tissue freezes when in contact with liquified gas

Safety program elements

-develop emergency procedures for police and fire department -develop list of emergency phone numbers including plant supervisor, chemical suppliers, hospital 2 or more, doctors 2 or more, ambulance 2 or more, fire department police department and chemtrec -establish how to make emergency phone call including location address and instruct where accident took place in plant and where person can be found, and open plant entry gate -prepare written rules on safety procedures to cover points listed -participate in periodic training including hands on use of safety equipment and use of safety procedures like use and maintenance of leak detection equipment, use and maintenance of leak repair equipment, respiratory protective equipment, atmospheric monitoring devices -establishes procedures for chemical leaks and first aid and establish maintenance and calibration program for safety device and equipment Employees should know hazards of handling chlorine, and where to find protective equipment and safety procedures followed, emergency checklist developed,

Abnormal evaporator conditions

-evaporator water level is low, water level not visible in sight glass Troubleshooting -determine actual level of water and measure temperature Check temperature and pressure gauge of chlorine in evaporator system and supply lines back to containers and chlorinator for possible overpressure of system with pressure not exceeding over 100 psi

Monthly evaporator duties

-exercise all valves including inlet outlet chlorine pressure reducing CPRV and water drain and fill valves -inspect evaporator cathode protection meter, which protects metal water tank (on sulfonator) and piping Fromm corrosion due to electrolysis. Electrolysis is flow of electical current and is the reverse of metal plating, the flow away of certain compounds from the metal causes corrosion and holes in a short time, and this corrosion is controlled by either a sacrificial anode made of magnesium and zinc or by applied small electrical currents to suppress or reverse normal corroding current flow. -check setting of CPRV in order to maintain desired pressure of chlorine gas to chlorinators - inspect heating and ventilation equipment in chlorinator area, maintain a higher temperature in chlorinator area tahn in the chlorine storage area -perform scheduled routine preventative maintenance such as Drain flush and water bath Clean evaporator tank Check heater elements Repack gasket and reseat pressure reducing valves annually Replace anodes annually Paint system annually

Extreme cases of exposure

-follow emergency procedures - use proper safety equipment -remove patient from affected area immediately call physician and begin appropraite treatment immediately -keep patient warm and cover with blankets -place patient in comfortable position on thier back -if breathing appears to have stopped, begin CPR immediately -if breathing is diffiicult, administer oxygen, if equipment and trained personnel are available -eyes: if small amount of chlorine is in eyes, flush immediately with large amounts of lukewarm water so all traces of chlorine are flushed from eyes 15 minutes, hold eyelids apart gently but firmly to ensure complete flushing of eye and lid tissues.

Shutdown sequence

-follow preliminary steps listed -close respective influent channel slide gate -turn all UV banks off in UV channel -drain the UV channel by opening the mud valve -wash UV channel and UV equipment -repair UV equipment or channel to place back into service

Disconnecting tank cars

-gather materials needed , keys to tool locker on chlorine tower, electrical safety tag, a buddy, no one is to work alone -verify valves are closed -tag pad air compressor so it will not be turned off during purging operations -check eyewash and shower facility -put on escape respirators -close valve that disconnects teh chlorine tower from process (chlorinator/evaporator area) -verify that pad air pressure is higher than liquid chlorine line -open pad air suppl valve to chlorine tower -install flex air hose to connect pad air piping to chlorine line -open pad air supply valve to chlorine tower -instal flex air hose to connect pad air piping to chlorine piping -open valves that allow air to force chlorine back to tank car -wait 5 minutes -clsoe valve on chlorine tank car Close valves and then crack open slightly, loosen chlorine coupling and test with ammonia gas for leaks -remove chlorine flex line -reassemble cap chlorineflex line and verify taht no air is escaping -close tank car vale farthest from chlorine tower -remove gauge assembly slowly and test with ammonia gas -put plugs back in chlorine tank car valves and secure lid -close pad air to chlorine valves -remove flex air hose to break pad air/chlorine piping -store all gear and lock tool cabinet -raise adn lock drawbridge -change department of transportations placards to read danger chlorine empty -place warning light and sign at the end of spur -unlock and open derailing mechanism -remove compressor tag -call railroad adn notify them to pick up empty tank car -record name of railroad official contacted -record date and time of disconnect on log sheet -sign bill of lading -sign name on log sheet to indicate taht on is completed

Connecting tank cars procedure

-gather materials needed from office including electrical safety tag key to tool locker on chlorine tower, and a buddy no one can work alone on chlorine tower -very system valve is appropraite have valve numbering system and valve positions for your installation -tag pad air compressor so it will not be turned off during purging -check emergency eyewash facility and deluge shower for proper operation -put on escape respirator -lower and lock down drawbridge -check valves on unloading tower are properly positions -open pad air valve if pad air pressure si higher than chlorine pressure. -open tank car lid and verify all car valves are closed check for chlorine leaks with ammonia -remove plug from tank car valve farthest form chlorine tower and install gauge assembly, check plug area with ammonia before complete removal because tanks ar valve may not be seated properly and use suitable pipe lubricant on male threads only -record tank car pressure if below desired leve, then padding tank car will be required -install flex air hose to connect pad air piping to chlorine piping -open valves to initiate purging of chlorine flex lien valves should be opened only slightly until chlorine flex line is connected completely -remove plug from tank car valve and connect chlorine flex line use new lead washer in the ammonia coup;ing for chlorine line -after no leaks can be heard, close valves -remove flex air hose to break pad air chlorine piping connection -open valve on tank car -open valves to process slowly, too raid opening may permit a sudden surge of chlorine and cause excess flow valve in educator pipe to close stopping flow Open valves this will connect chlorine unloading tower to chlorine building -store all gear and lock tool cabinet -remove compressor tag -record date and time job was completed on log sheet -sign name on log sheet -record date and time tank car was placed in service -record date and time tank car was taken out of service

Guidelines of chlorine emergency paln

-have fire department and emergency response agencies tour area and know where facilities are located, give clearly marked map indicating location of chlorine storage area,chlorinator and emergency equipment -have regularly scheduled practice sessions to use respiratory protective devices, chem suits, and chlorine repair kits, involve personnel who may respond to leak -have a supply of ammonia ready to detect chlorine leaks -write emergency procdure -develop emergency evacuation plant and coordinate with police and other offficals -post emergency procedures in operation areas - follow established procedures during all emergencies -inspect equipment routinely and make repairs -at least twice weekly, inspect areas where chlorine is stored and chlorinator are located, remove all obstructions from areas -schedule routine maintenance on all chlorine equipment at least once every six months or more -have health appraisal for employees on chlorine emergency duty and ensure they have no heart or respiratory problems that prohibit them from being on emergency team. Check other physical constraints

To achieve accuracy and safety with sulfonator, the sulfonator should have

-indicating meter rotameter -Sulfur dioxide metering orifice V notch -manual or automatic feed rate adjuster - vacuum differential regulating valve -pressure-vacuum relief valve -injector Feeding system is found in various sizes These sizes refer to the maximum amount of chemical that can be fed through control system in pounds per day Sulfonators mounted on 150 pound cylinders are most common

Injector system design list

-injector water pressure gauge -injector vacuum gauge for remote injector installation -injector vacuum line shutoff valve at remove injector location -sulfur dioxide solution pressure gauge located immediately downstream of injector to indicate injector back pressure -injector water pressure switch for low water pressure alarm -injector water flowmeter for multiple sulfonator systems

Start up liquid sulfonator

-inspect all joints manifolds and tubing connections -if system was exposed to atmosphere at all, then verify it is dry by determining dew point and turn evaporator on if not dry, important as moisture in system can cause serious corrosion damage and entire system may have to be repaired -start up evaporators fill water bath and adjust device according to manufacturers directions -turn on evaporator heaters, wait till temp reaches 180F before next step -inspect and clsoe all valves on SO2 supply line -open sulfur dioxide metering orifice slightly this is to prevent damage to rotameter -start injector water supply system -examine injector water supply system noting water supply pressure gauge and see pressure inlet is greater than 50 psi for injectors and note the injector vacuum gauge as if this is less than normal, then machine may function at lower feed rate, but willl be unable to deliver the maximum rated capacity - inspect sulfonator vacuum lines for leaks -close all valves on supply line -crack open gas line on SO2 container, all liquid sulfur dioxide systems should be checked by using gas because of danger of leaks and gas is better to leak than liquid. Check with ammonia cloth at all points. Before allowing sulfur dioxide to enter evaporator and sulfonator, make sure all valves between evaporator and sulfonator are open, as the heat in evaporator will cause gas to expand and if system closed, excessive pressure can develop. Sulfur dioxide should never be trapped in line, evaporator or sulfonator because heat could expand gas to point were pressure levels are a dangerous. -if no problems found then the supply line to evaporator can be put in service by opening valve 1 and 1/2 to 2 turns -check operation of sulfonator by looking at equipment working through complete range of sulfur dioxide feed rates, has working condition on manual and automatic settings, and if operating right, close gas line from sulfur dioxide container and slowly open liquid sulfur dioxide control valve, after admitting liquid sulfur dioxide into system, wait until temp of evaporator again reaches 180F to inspect evaporator performance. -system is ready for normal operation

Recieving tank cars

-inspect and refuse deliver if car damaged or has corrosion -spot the tank so unloading platform is aligned with car catwalk -verify railroad has breaks on -set two wheel chocks, one before and after, on rail nearest to chlorine tower -place warning light and sign one car length from tank car -dose adn lock derailing mechanism - record on log sheet date and time the tank car arrived and was accepted or rejected -sign name to log sheet

Container storage area Daily operation tasks

-inspect building or are for ease of access by authorized personnel to perform routine and emergency duties -be sure fan and ventilation equipmentare operating - read scales charts or meters at same time every day to determine use fo chlorine and any other chemical Notify superintendent when chlorine supply low -look at least once per shift for chlorine or chemical leaks -try to maintain temperature of storage area below temp of chlorinator room -determine manifold pressure before and after chlorine pressure regulating valve by reading upstream and downstream -be sure all chlorine containers are properly secured

Piping maintenance

-inspect piping periodically, if any discoloration appears, replace the piping and test it. Repair any leaks discovered during inspection -all joints should be tested periodically -all fittings when taken apart should be checked for wear.those that are worn must be changed and proper gaskets should be available for use. Use new gaskets -whenever joints are opened, they should be plugged immediately. This should be done to prevent moisture from getting into the system and causing serious damage -flexible connection should be properly stored so it will not get kinks and thus be weakened and susceptible to leaks. Before use it should be thoroughly dried. Change the flexible connection periodically and throw away the old one -record all performed maintenance and repairs

Dechlorination treatment processes

-long detention periods, prolonged detention give sufficient time for dissipation of residual chlorine -aeration bubbling air through water with chlorine residual in the last portion of long narrow chlorine contact basins will remove chlorine residual -sunlight- chlorine is destroyed by sunlight exposure and accomplished by spreading effleunt in thin layer and exposing to sun -activated carbon- residual chlorine can be removed by adsorption done by activated carbon -chemical reactions- sulfur dioxide is used as it reacts immeditealy with chlorine on one to one basis Sulfur dioxide is most popular chemcial method to achieve removal of chlorine

UV channel water control device is regulated by operators to achieve

-minimize variation of channel water level - maintain channel water level at defined level -keep the UV lamps submerged at all times -prevent excessive water layer thickness above the top lamp row

Procedures for emergencies

-never work alone during emergency Obtain help immediately and quickly repair problem -only authorized and trained persons with adequate equipment should be allowed in danger area -if caught in chlorine atmosphere, shallow breaking is safer than deep breaths, recovery depends on duration and amount of chlorine inhaled, so keep amount as small as possible -if you discover chlorine leak, leave area immediately unless it is very minor, get equipment on then repair. Check small leaks with ammonia rag white gas will form if chlorine is present. Don't spray onto leak or spray ammonia on metal Notify police depearmtnet that you need help if it becomes necessary to stop traffic on roads and evacuate person in vicinity of leak.

Long term shutdown chlorinator

-perform steps 1 2 3 4 Turn off chlorinator power switch lock out and tag out Secure chlorinator gas manifold adn chlorinator valve in closed position

How treatment removes pathogenic organisms

-physical removal through sedimentation and filtration -natural die off of organisms in unfavorable environment - destruction by chemicals introduced for treatment

Equipment shutdown start up preliminary procedure

-plan ahead Determine how unit start up or shutdown affects other units calculate how change in flow distribution will affect flow rates unit capacity solids concentration and effluent quality Determine how unit start up or shutdown will affect process control -check switches When starting piece of equipment check to ensure all local and panel switches connected with unit and it's associated equipment are in off position When shutting down, label all breakers and local power disconnects for equipment associated with unit and lock out tag out -Clean units Before start up and after shut down -prepare equipment Close all breakers and local power disconnects Prepare equipment for start up by following instructions laid out by manufacturer O and M manual -set controls Follow operation O and M manual For alternative operation, set equipment controls as needed to implement chosen process control strategy

Weekly chloraintor injector tasks

-put chlorinator into manual control, operate feed rate adjustment through full range from zero to full scale , at each end fo scale check for chlorinator vacuum, injector vacuum, solution line pressure, chlorine pressure at chlorinator, -if any readings do not produce normal set points make adjustments -injector should rpoduce vacuum 5-10 inches of mercury adjust CPRV to obtain sufficient pressure and chemical feed operation of chlorinator CPRV is on main chlorine supply line and is located near chlorine container area - if unit performs properly through range of feed rates then return to automatic control, -clean chlorine residual analyzer by -cleaning filters, sample line, hydraulic dilution wells and baffles, discharge hoses and pipes and flush them, clean and flush cell block, fill buffer reservoirs, check buffer pump and feed rate, wipe machine clean and keep it clean.

Chlorination of wastewater yeilds these types of effects

-reduce BOD by least 2 mg/l for each mg/L of chlorine absorbed up to the point at which residual is produced -reduction is increased with increasing chlorine dosages, this addition has limits -reduction seems to be permanent

Evaporator maintenance

-should be cleaned every 6 months if supply of sulfur dioxide is dirty, clean evaporator more frequently -after been cleaned 10-12 times, it should be completely taken apart and cleaned. this should be done every 5 years on mandatory basis regardless of cleaning schedule -the manufacturers cleaning procedure should be followed -new gaskets should be used never use old worn parts -record of any done maintenance or repairs should be kept

Sulfonation system shutdown procedure

-shut off the sulfur dioxide supply, if the downtime is for a brief period, supply can be shut off at the valve near the sulfonator, if downtime for day or more it is better to shut the supply valve at the source. This allows all the SO2 to be removed from system - if equipment is to be dismantled wait until SO2 supply pressure gauge reads zero, then remove the flexible connection at the source while still running the equipment attach the dry air to this connection. This will ensure that all traces of SO evacuated -after you are sure SO2 are gone, injector may be turned off this will secure the installation. Dry air supply also should be turned off at this time -secure the open end by putting a plug on the flexible connection end this will prevent moisture from entering the piping -begin repairs

Checking evaporator gauges for proper operation

-water level indicates level of water in bath, level should sit in center of sight glass -water temp should be 180-195 F -gas temperature range is 90-105F as impurities are deposited on the evaporator wall, the gas will show a drop in temperature, with experience, the operator should be able to determine when thee evaporator needs cleaning -gas pressure should read same pressure as the supply cylinder or tank -cathodic protection should be in place to prevent corrosion damage, meter should normally read in the 50-200 range

Rotameter

A device used to measure the flow rate of gases and liquids. The gas or liquid being measured flows vertically up a tapered, calibrated tube. Inside the tube is a small ball or bullet-shaped float (it may rotate) that rises or falls depending on the flow rate. The flow rate may be read on a scale behind or on the tube by looking at the middle of the ball or at the widest part or top of the float.

Eductor

A hydraulic device used to create negative pressure suction by forcing a liquid through a restriction such as a Venturi, an eductor or aspiration (the hydraulic device) may be used in laborator in place fo vacuum pump as an injector, it is used to produce vacuum for chlorinators sometimes used instead of suction pump

Colorimetric measurement

A means of measuring unknown chemical concentrations in water by measuring a sample's color intensity. Specific color of the sample, developed by addition of chemical reagents is measured with photoelectric colorimeter or is compared with color standards using or corresponding with, known concentrations of chemical

DPD method

A method of measuring the chlorine residual in water. The residual may be determined by either titrating or comparing a developed color with color standards. DPD stands for N,N-diethyl-p-phenylenediamine.

Nitrogenous

A term used to describe chemical compounds (usually organic) containing nitrogen in combined forms. Proteins and nitrate are nitrogenous compounds.

Ballast

A type of transformer taht is used to limit the current to an ultraviolet lamp

Post chlorination

Addicting chlorine to water after all other treatment processes Point of application should be before chlorine contact chamber, and after final settling unit in treatment plant, most effective place is after treatment and on a well clarified effluent used primarily just for disinfection, disregarding other benefits chlorinating may present. Some reduction of BOD in effleunt is also achieved, but chlorination is rarely practiced solely to reduce BOD.,

Prechlorination

Addition of chlorine at entrance of plant, ahead of settling units and other chemcial additions.can help remove oil and contorl foaming in imhoff units Current trends are moving away from rpechlorination and replacing it with up sewer aeration or other chemical treatment

Prechlorination

Addition of chlorine in collection system serving the plant or at the headworks of the plant prior to other treatment processes mainly for odor and corrosion control. Also applied to aid disinfection, to reduce plant BOD load to aid in settling, control foaming in imhoff units, and to help remove oil

Valves

All material in valving system should be approved by by chlorine institute Problems arise using bronze bodies and monel stems and seats Better results have been obtained using 316 stainless steel with teflon seats Plastic valves like PVS hae been use don solution lines with good results

Best measurement of chlorine residual

Amperometric titration, but it costs more than other equipment for other methods, startch iodide test can e used but will not work well in turbid or muddy water, DPD tst can be used and are less expensive, but is also colorimetric and affected by clarity. Orthotolidine tests are no longer practiced

Chlorine tank cars

Are of 16 30 55 85 90 ton capacity All have 4 inch cork board insulation protected by a steel jacket Dome of standard car contains 4 angle valves plus a safety valve. The safety valve has a relief pressure f either 225 psi or 375 psi depending of test pressure of tank car Test pressure for the car is identified by last three digits of classification number located near the right end of the car. Two angel valves located on axis line of tank are equipped with discharging liquid chlorine, the two angle valve at right angles to the axis of the tank deliver gaseous chlorine Unloading of tank cars should be performed by trained personnel in accordance with interstate commerce commission regulations Usually chlorine si withdrawn from tank cars as a liquid and then passed through chlorine evaporators Sometimes dry air is passed into the tank car through one fo the gas valves to assist in liquid withdrawal this is referred to as AIR PADDING

Ton tanks

Are of welded construction and have loaded weight of as much as 3700 lbs tehy are about 80 inches in length and 30 inches in outside diameter. The ends of tanks are crimped inward to provide a substantial grip for lifting clamps The following are characteristics of tanks -tanks have eight openings for fusible plugs and valves. Generally two operating valves are located on one end near the center. There are 6-8 fusible metal safety plugs, three or four to each end and these designed to melt with same temp as the safety plug in cylinder valve. Ton tanks are shipped by rail in multi unit tank cars. They also may be transported by truck or semi-trailer Ton tanks should be handled with a suitable lift clamp in conjunction with a list or crane of at least two ton capacity ton tanks should be stored and used on thier sides above the floor or ground, on steel or concrete supports they should not be stacked. Ton toanks should be placed on trunnions that are equipped with rollers so that withdrawal valve may be positioned one above the other. The upper valve will discharge chlorine gas, and the lower valve will discharge liquid chlorine The ability to rotate tanks is also a safety feature, in case of liquid leak, container can be rotated so that the leaking of chlorine escapes as a gas rather than a liquid, trunnions rollers should not exceed 3 1/2 inches in diameter so that the containers will not rotate too easily and be turned out of position . Roller shafts should be equipped with a zero-type lubrications fitting, Roller bearings are not advised because of the ase with which they rotate Locking devices should be used when these rollers are used to prevent ton tanks from rolling while connected.

Hypochlorite solution

Because hypochlorite ions are relatively ineffective disinfectant, sodium hypochlorite solution should be as dilute as possible this is extremely important in disinfection As phychlorite tends to increase pH of solution, when a pH of 10 is reached, pypochlorius acid (better disinfectant) dissociates and breaks down which is a bad loss

Chlorination before filtration

Better designs provide means of chlorinating secondary effluent before filtration to. Kill algae and other large biological organisms Chlorination of effluent before filtration tends to prevent biological growths in filter media, thus chlorine should be added after filtration or postchlorination would be in addition

Routine maintenance for UV systems

Capable of continous use if simple routine is performed at regular intervals Check following items regularly operator of UV system can determine when maintenance is needed -check the UV monitor for significant reduction in lamp output -monitor process for major changes in normal flow conditions such as incoming water quality -check for fouling of quartz sleeves and UV intensity monitor problems -check indicator light display to ensure al the UV lamps are energized -monitor elapsed time meter microbiological results, and lamp log sheet to determine when UV lamps require replacement -check quartz sleeves for discoloration this effect of UV radiation on quartz is called solarization excessive solarization is indication that a sleeve is close to end of its useful service life. Solarization reduces ability of sleeves to transmit necessary amount of UV radiation to process Maintenance of UV systems require cleaing the quartz sleeves and changing the lamps Algae and other biological growths may form on walls and floor of UV channel, slime can slough off potentially hindering the disinfection process and when this is happening, then dewater UV channel and hose out to remove accumulated algae and slimes

Pre-Start up sulfonation process

Check operators know where shutoff valves are located and safety program established before starting system Should be cleaned dried and checked for leaks before starting Flush pipelines with cleaning savant Steaming with super hot dry steam from high elevation side of system and allow condensate and foreign material to drain out, then blow dry from one end of line to other and purge with nitrogen gas Test dry air for moisture by running dew poin test using padding air compressor air supply Test system for leaks by pressurizing up to 150 psi Maintain for 24 hours at this pressure Drop in pressure may occur to hot compressor air cooling in system If pressure drop is due to leak, inspect for leaks at lints and valves using soapy water Small amounts of sulfur dixoide sould be used. For first time, and use respiratory protector for first time start up. Close supply system at first sign of odor. Sulfonator should be used during this check out otherwise there will be no place for sulfur dioxide to go If leak develops sulfonator should be set at highest feed rate possible in order to drain the system of sulfur dioxide so leak can be repaired

High resolution redox HRR units control

Chlorination and dechlorination chemical feed rates according to actual demand in treatment process, these HRR units automatically treat waste stream with chlorine and sulfur dioxide dosages required to maintain chemical residuals in ideal ranges, regardless of changes in chemical demand or stream flow Maintenance consists of cleaning units sensor once a month for chlorinator sensor at least Insure sulfur dioxide controller is highly responsive at all ties, and cleaned 3 times a week ORP probes are very effective by industries when waste constituents are constant, but in municipal waste water situations, regular fluctuations in waste in entire chlorination system must be known before starting or stopping any portion of system During emergencies, act quickly and you may not have time to check out each of the steps mentioned, but still follow established procedures.

Odor control by chlorine

Chlorination inhibits growth of door producing bacteria and destroys hydrogen sulfide H2S most common odor nuisance

Activated sludge and chlorine

Chlorination of return sludge in range of 1 to 10mg/l reduces bulking of activated sludge that caused by overloading Point of application should be where the return sludge will be in contact with chlorine solution for about one minute before sludge is mixed with incoming settled wastewater. Commonly used to control filamentous bacteria. Chlorine used in this manner is expensive alternative for adequate design and operation. Main effort should be directed toward process improvement, and chlorine serve as emergency solution

Step rate contorl

Chlorinator feed rate is varied according to number of water pumps in service Each pump starts, a preset quantity of chlorine is added to flow of chlorine existing at starting time, this system can be applied conveniently with installations using up to eight pumps

Factors influencing disinfection

Chlorine addition amount Contact time, Suffcient chlorine must be added after chlorine demand is satisfied to achieve a chlorine residual likely to persist through contact period, -injection point and method of mixing to get disinfectant in contact with water -design or shape of contact chambers, rectangular contact chambers allow short circuiting a dn consequently reduced contact times, baffles often are installed to increase mixing action obtain better distribution of disinfectant, and reduce short circuiting which increases contac titme and pipelines make good contact chambers -contact time with good initial mixing, the longer contact time, better disinfection, most chlorine contact basins are designed to provide contact time with 30 minutes, extended chlorine contact time is more effective than increasing chlorine dose to improve disinfection - effectiveness of upstream treatment processes, lower suspended solids and dissolved organic content in water better disinfection -temperature, higher the more rapid rate of disinfection - dose rate and type of chemical, normally higher dose rate, quicker disinfection rate, form or type fo chemical influences disinfection rate -pH lower pH better disinfection -number and types of organisms, greater organisms concentration, longer time required for disinfection, bacterial cells are killed quickly and easily, but bacterial spores are extremely resistant

Chlorine demand formula

Chlorine demand = Chlorine Dose (mg/l) - Chlorine residual (mg/l)

Chlorine demand

Chlorine demand is the difference between the amount of chlorine added to water or wastewater and the amount of chlorine residual remaining after a given contact time. Chlorine demand may change with dosage, time, temperature, pH, and nature and amount of the impurities in the water. Chlorine Demand, mg/L = Chlorine Applied, mg/L - Chlorine Residual, mg/L

Chlorine dioxide

Chlorine dioxide reacts with water to form chlorite ion chlorite ion and hydrogen ions Oxidizing capability of chlorine dioxide is not all use din wastewater treatment because the reactions with the substances reducing agents in wastewater only form chlorite , and therefore chlorine dioxide is not as reactive as chlorine and chlorine is a better oxidant, in waters with pH of 8.5 chlorine dioxide is a very effective disinfectant Chlorine dioxide also wont react with ammonia. It is also very unstable, and must ge generated at plant site, chlorine dioxide si prepared by injection of sodium chlorite into chlorine solution line from a chlorinator Chlorine dioxide has more potential for applications in water treatment field tahn in wastewater treatment because chlorine dioxide is ess likely to produce cancer causing compounds or cause tastes and odors in water

Time program contorl

Chlorine feed rate i varied on timed step rate basis regulated to correspond to the times of flow changes or by using time pattern transmitter tht uses a revolving cam cut to match a flow patter

Abnormal conditions

Chlorine leak in chlorinator - shut off gas flow leave injector on line and place different chlorinator on line, Allow chlorinator to operate with zero psi showing under a vacuum and chlorine pressure gauge is at 0 for 5 minutes to remove gas. If system be opened to repair leak, vacuum on chlorinator may prevent exposure to gas released into atmosphere, use respiratory protection Chlorine gas pressure too low less tahn 20 psi -empty containers switch to standby unit -evaporator shut Down -inspect manifold for closed valves or restricted filters, correct by swithcing to another manifold, cleaing replacing filters, setting valves and controls to proper position -injector vacuum too low Adjust injector toachieve required vacuum, inspect injector to achieve required vacuum Pump off start pump, strainers dirty clean strainers, pump worn out and will not deliver flow and pressure to injector, use other unit or repair and replace pump Inspect valves in system place valves in proper position Inspect solution line discharge downstream from injector check Valve closed or partially closed, line borken or restriction reducing flow or increase in back pressure, diffuser plugged thus restricting flow and creating a higher back pressure on discharge line and injector clean diffuser and flush pipe Installation of pressure gauge on discharge side of injector or suction line would alert operator to abnormal system back pressure. Low chlorine residual- alarm indicator is on from chlorine residual analyzer -determine actual residual and compare with chlorine analyzer, recalibarate analyzer and readjust if chlorine residual analyzer is correct and chlorine residual is low check Sample pump Operation flow and pressure sample lines clean and free of solids or algae that could create chlorine demand, strainer dirty or restricting flow thus preventing adequate pressure 15-20 psi Control system, if chlorinator is on automatic contorl, chlorine feed rate remains too low take chlorinator onto manual control,set to proper feed rate determined by previous adequate feed rates Chlorine demand higher than amount one chlorinator can supply, add another unit High chlorine usage, effleunt appears low in solids, yet coliform count is high, may be caused by either nitrite lock or breakpoint chlorination problems, nitrite lock is when nitricaiton is not complete

Hypochlorinators

Chlorine pumps or devices used to feed chlorine solution made form hypochlorite like bleach, calcium hypochlorite Available as liquids or various forms fo solids powder pellets Systems consist of water meter and a diaphragm metering pump, pump feeds hypochlorite solution in proportion to wastewater flow

Hypo-chlorinators

Chlorine pumps, chemcial feed pumps or devices used to dispense chlorine solutions made from hypochlorite, such as bleach (sodium hypochlorite) or calcium hypochlorite into water being treated

For chlorinator setting formula, note

Chlorine requirement should take into consideration the chlorine demand so taht a desired residual is obtained after given contact period, chlorine need varies by variety of factors, and main goal of adjustment of chlorinator feeder rates it to meet all these variations is ultimate goal for good operation More frequent adjustments are needed for primary effluent than secondary effleunt.

Valves and manifolds

Chlorine valves consist of -auxiliary tank valves for use at the container -header valves for use on or in conjunction with manifolds -line valves for insertion in liquid and gas lines for shutoff procedures -pressure reducing valves to reduce pressure in gas lines where necessary Manifold assemblies designed to recieve flexible connections from containers generally provide a shutoff valve, and include means fo connecting to current chlorinator piping There are available in types and sizes and accommodate any required number of containers and may be mounted in any convenient manner

Chlorine reaction with inorganic compounds and nitrogenous compounds

Chlorine will react with organic matter and produce chlororganic compounds or other combined forms of chlorine, which have slight disinfecting action. If enough chlorine is added to react with all the aboce compounds, any additional chlorine will exist as free chlorine, which has the highest disinfecting action This situation rarely exists in wastewater that contains nitrogenous compounds,

STA weekly jobs

Clean building or strategy area Check operation of chlorine leak detector alarm

Determining if chlorine demand is caused by nitrite lock or breakpoint chlorination test

Collect sample of effleunt from chloraintion in 250ml beaker Pour 100 ml into another beaker Add several potassium iodide crystals to sample beaker and mix Add 5 glacial acetic acid or white distilled vinegar if yellow orange or red then nitrite present If color produced is not obvious add squid of starch solution if blue appears, nitrite is present, if no color appears then its breakpoint chlorination

Chloramines

Compounds formed by the reaction of hypochlorous acid (or aqueous chlorine) with ammonia.

Why chlorine must be handled with care

Concentrations of ga excess 1000 PPM .1 volume of air can be fatal after few breaths Gas is noticeable even when amount in air is small, most times you can get out of gas area before serious harm is suffered.

Chlorine residual informaiton can either

Confirm previous chlorinator feed rate setting or indicate need for adjustment of setting

Types of UV lamps

Consists of UV lamp enclosed in individual quartz sleeve with ends appropriately sealed using O ring and quartz end plug All lamps in UV system are identical Three types -low pressure low intensity y -low pressure high intensity -medium pressure high intensity

Cylinder chlorine containers

Contain 100-150 pounds Convienent to small treatment plants with capacity less than .5 MGD These cylinders are usually of seamless steel construction Fusible plug is placed in valve below valve stem Plug is safety device, the fusible metal solvents or melts around 158-165 F to prevent build up of excessive pressures and possiblity of rupture due to a fire or high temp Cylinders will not explode and can be handled safety Following are procedures for handling chlorine cylinders -move cylinders with properly balanced hand truck with clamp supports taht fasten at least 2/3 way up cylinder 100 and 150 pound cylinders can be rolled in a vertical position Lifting of these cylinders should be avoided except with approved equipment Use a lifting clamp, cradle, or carrier never lift with chains rope slings or magnetic hoists -protection hood or cap should always be replaced when moving a cylinder - cylinders must be kept away from direct heat -cylinders are stored in an upright position -cylinders must be firmly secured to an immovable object. Use safety chain or clamp to prevent empty or full containers from falling over or being knocked down -store empty cylinders separately from full cylinders, never store chorine cylinder near turpentine ether anhydrous ammonia, finely divided metals, hydrocarbons or other materials that are flammable in air or react violently with chlorine

minimum UV dose management

Control of programmable logic controller is to manage minimum UV dose applied to UV channel Actual UV dose control is controlled for each UV channel and based on maintaining minimum dosing level. Usually maintenance of minimum dosing level is done with flow pacing Applied dose is calculated from flow rate and end of lamp life intensity at specified tranmittance multiplied by ballast power that is 50 percent power results in half the intensity Dose calculation is based on recieved dose derived from flow and input from intensity sensors PLC also controls UV intensity in UV channel. Has its own ballast control loop using intensity set point at its target Calculates lowest intensity of the banks ot use to achieve disinfection then it adjusts ballast lamp power to achieve the intensity set point . Summary of UV system programmable logic controller goes -recieves minimum UV intensity from preset ale which is field adjustable -received target UV intensity from preset valve that is field adjustable -compares target UV intensity with actual UV intently -makes adjustment to out put of power of all ballast cards in operation If actual UV intensity goes below minimum UV intensity for more than 2 minute then low intensity channel bank alarm will go off and flag the bank as failed. This will shut down failed bank after 10 minutes. Level of ballast output power is identical to ballast cards in UV banks UV system aims to achieve minimum dose at all times with safety margin to accommodate operational shits and procedures -as flow increases or transmission reduces, UV dose will be reduced an PLC will increase ballast output to compensate. Will start up assist bank when duty is 85 percent power or dose is less tha design plus safety factor As flow decrease or tranmission increases, UV will be increased and PLC will reduce ballast output to compensate it will shut down a sit bank when ballast output is 50 percent and dose is greater than design and safety factor with output on duty. Bank will be increased to 100 percent before shutting down assisting bank/

Sulfonator feed rate contorl

Control of sulfur dioxide to point of application in plant effluent is accomplished like controlling chlorine flow Control of sulfur dioxide feed rate to plant effluent to remove chlorine residual depends on -chlorite residual mg/L Plant flow rate MGD Amount of chlorine to be removed after addition of sulfur dioxide

Tank drop formula

Convert feet to inches 12 inches per foot

Blueprint reading formula

Convert length and widths from inches to feet or fractions Then length times width

Preventing nitrite lock

Correct nitrite lock immediately to prevent wasting of nitrobacter into system -reduce level of nitrification this si only viable if nitrification is required -add supplemental alkalinity if pH of secondary effluent is below 6.8 this can prevent the low pH from inhibiting nitrobacter -increase ammonia concentration above nitrite concentration, this will introduce a non-nitrified effluent, a high ammonia implant recycle stream, or commercially available ammonia. If ammonia concentration is higher than itrtie, chloramines will form that do not react with nitrite

Chlorination to treat H2S or hydrogen sulfide

Correction of odor problem and require a decision made between system modification and treatment,. Depends on costs involved, sometimes modifications to major treatment components are far more costly tahn treatment. Use of air or ozone can help with odors, but chlorine is most ifianiclay feasible Rate of sulfide production increases with temp

UV technology for cleaning

Damages the genetic material of organisms so they no longer grow or reproduce Has high energy costs and technological difficulties.prevents widespread use of UV systems for disinfection. Gaining popularity with risks concerning chlorine being more risky

Chlorinator job

Delivers chlorine to point of application by vacuum solution feed, the chlorine gas is controlled metered and introduced into stream by injector water and then conducted as a solution to point of application Cavuum operation is safest, as if it fails, it stops flow of chlorine into system or allows air into vacuum system instead of chlorine out If chlorine inlet shutoff fails, vent valve discharges coming gas to outside of chlorinator building Operating vacuum provided by hydraulic injector. Injector operating water absorbed gas, and resultant chlorine solution is conveyed to chlorine diffuser through corrosion resistant conduit Vacuum chlorinator also include vacuum regulating valve to dampen fluctuations and give smooth opeartion Chlorine gas flows from chlorine container to gas inlet, after entering chlorinator, the gas passes through rotameter which indicates state of gas flow, the rate is controlled by V notch variable orifice Gas then passes through spring loaded pressure regulating valve, then moves into injector where it is dissolved adn water and leaves chlorinator as chlorine solution

Ultimate control on chlorine dosages

Depends on disinfection results desired Bacterial level or concentration acceptable or permissible at point of discharge Determine your chlorine requirements according to current edition of STANDARD METHODS FOR EXAMINATION OF WATER AND WASTEWATER Chlorine requirement or dose will vary with wastewater flow , time of contact, temp, pH, and major waste constituents in water.

Effectiveness of treatment

Depends on type of treatment process and hydraulic and organic loadings Treatment process and microorganism removal percent listed on page 347

Protection of structure by chlorine

Destruction of hydrogen sulfide by chlorine also reduces production of sulfuric acid that eats away at sewer systems and structures. Particularly significant where temperatures are high and time fo travel in sewer system are long. Treatment is similar to those that fro odor control Can also correct sulfide problems with oxygenation of sewer. But depends on costs and safety risks involved Chlorine leaks are dangerous, but chlorine is cheaper and more effective tahn oxygenation in sewer

Detecting sulfur dioxide leaks

Detected from smell if leak present Can be found with ammonia vapors dispensed from aspiration or squeeze bottle Aspirator doesn't work if roomies full of gas. Can also use ammonia swab to detect leaks Dense white fume forms when ammonia in presence of sulfur dioxide Never use soapy water to look for leak as water combines with sulfur dioxide to form sulfur acid which is corrosive and worsens leak

Determinations for pipes valves and manifolds

Determine -availability of various types of chlorine container and select best types for plant needs -inventory required and space needed for chlorine equipment -method of handling containers - type of weighing scales to be used -final step is plan for chlorine supply and required piping

Definition of hypochlorite compounds by manufacterer to calculate available chlorine

Determine available chlorine as amount of gaseous chlorine required to make equivalent hypochlorite chlorine If you preparer hypochlorite solution for disinfection and immediately measure chlorine residual, you find chlorine residual about Half of expected valuebased on manufacturers amount of available chlorine When mixed with water, half of chlorine forms hydrochloric acid, and other half forms hypochlorite, chlorine residual you measured.

Method of control

Determined by design engineer with cost and desired effect in mind Could use a compound loop system or manual control if funds was short If operator is not at plant 24 hours a day then automatic control should be considered

Chlorine requirements for various flow rates and contact times

Determined by plant or lab scale If determination is made on lab scale, plant requirements are often higher. Mixing and actual contact times can be more carefully controlled in laboratory. Determinations should be made by comparing results of both methods, if chlorine requirement as determined by full plant test is significantly greater than lab testing, a wasteage of chlorine is indicated. Two major causes of large discrepancy is poor mixing at point of chlorine injection and short circuiting in contact chamber Both problems can be solved with minor expenses.

Troubleshooting dechlorination tablet feeders

Determingin the correcting of the cause of delivery and incorrect amounts of sulfite. Potential problems and their remedies are outlined in following paragraphs

Annually tasks chlorinators

Disassemble clean and regasket chlorinator

Plants required to provide chlorination dechlorination services for

Disinfection- postchlorination of effluent Process control- activated sludge RBC and trickling filter treatment process Odor contorl- seasonal during warmer months from may to october Dechlorination- seasonal during july through november,

Monitoring influent and effluent characteristics

Do not exceed maximum design turbidity levels and flow velocities when using equipment Suspended particles shield microorganisms from UV. Light Flows should be somewhat turbulent to ensure complete exposure of all organisms to UV light but velocity controlled so waster exposed to UV radiation long enough and detention times are high to point of disinfection occurs. Since ultraviolet rays leave no chemcial residual like chlorine does, bacteriological tests must be made frequently to ensure adequate disinfection achieved by system No protection from decontamination is present in water as no chemical disinfectant is present. When treated waster is exposed to visible light, microorganisms can be reactivated. Organisms not killed ahve ability to heal themselves when exposed to sunlight Solution to this is to design UV system to high enough efficiency to achieve the killing of organisms

Valves

Do not sue wrenches longer than 6 inches pipe wrenches or wrenches with extension on container valves. They exert too much force and break valves. Use only square end open or box wrenches. Strike end of wrench with heel o hand to unseat valve, then rotate valve stem then open slowly. Loosen packing gland nut if stem is too tight to turn. Then retighten packing nut.

Sulfur dioxide control facilities

Do not use manual control of equipment for normal operation but use it when equipment failures occur Operating under manual or with smaller direct mounted sulfonators require operator to change dose rate manually every time their is flow change or a chlorine residual change. This is done by turning control knob to adjust proper dose rate of sulfur dioxide.

Copper tubing

Don't bend copper tubings leaks will form. Use a sling to hold tubing when disconnecting from empty cylinder to prevent tubing from flopping around or getting dirty or kinked. Cap or plug connectors to prevent dirt accumulation inside pipe. Shutoff valve is needed to simplify changing containers. Whenever changing chlorine container use new washers or gaskets.

Chlorine residual determination

Done by several lab tests Method of choice must be one of those approved by state or federal water pollution contorl agencies or not recognized Amount of residual that one should maintain is determined by desired microorganism population The microorganism population is usually specified by state or federal NPDES permit requirements This determination does not test for individual pathogenic microorganisms, but instead uses coliform group organisms as indicator organisms

How to dechlorinate

Done by using sulfur dioxide, sodium sulfite or sodium metabisulfite Activated carbon has been used as well But it is extremely expensive to use activated carbon in large applications

Chlorine costs

Easy to obtain and cheap to manufacture Extremely effective at low doses

Protection against chlorine

Employee trained on how to handle chlorine and appropraite use of respiratory protective devices and methods of detecting hazards, and know emergency protocols Self contained air supply and demand breathing equipment must fit properly and be used properly, pressure demand and rebreather kits may be safer Pressure demand units use more air from air bottle, which reduces time a person may work on leak, and certain physical Constraints when using resperitroy protection Before entering area with leak, wear protective clothing, prevents chlorine from contacting sweat on body and forming hydrochloric acid, chemical suits are cumbersome but necessary, and worn when chlorine concentration is high.

Chlorine safety program

Employer must provide funds for safety equipment and to enforce safety regulations required by OSHA and industrial safety program

Startin chlorination system

Entire. Chlorination system status must be known before starting or stopping any portion of the system.

Overdose

Excessive overdose of the tablets can cause reduction of DO and effect on pH and corrected by removing feed tubes or using larger weir You can use 1/4 or 1/2 inch thick PVC spacer disks in tablet feeders to reduce chemical dose, the spacers placed in bottom of feeder tubes prior to loading tubes with tablets and raisethe entire stack of tablets off the floor of tablet feeder causing fewer tablets to be contacted by water during normal operation

STA monthly tasks

Exercise all valves, including flex connectors auxiliary manifold, filter bypass and switchover valves Inspect al flex connectors and replace any that have been kinked or flattened -inspect hoisting equipment cables for fray or cuts, container hoisting beam and hooks for cracks or bends, controls for operations working properly and do not stick or respond sluggishly, cords not frayed safety chains or bales in place, and hoists travels on monorail easily and smoothly -examine building ventilation for ducts and overs clean and operate freely, fans and blowers operate properly guards in place and equipment properly lubricated -perform preventative maintenance as scheduled with equipment lubricated monthly or quarterly, repack valves and regulators done 6-12 months, clean and replace vale seats and stems annually, clean filters and replace glass wool annually, paint equipment annually, and inspect condition and parts of all repair kits and safety equipment monthly

Start stop control

Feed rate adjustment done by hand, starting adn stopping by interrupting injector water supply, is controlled by starting water pump flow switch and level switch

Flow proportional contorl

Feed rate on chlorinator is controlled by system that converts water flow informaiton into chloriantor control valve settings, this can be accomplished by metering equipment, including all process contorl instrumentation presently available and nearly all metering equipment not in use on water systems.

Application point of sulfur dioxide or sodium sulfite.

For dechlorination to be achieved, you need -proper dosage based o precise monitoring of combined chlorine residual -adequate mixing at point of application, the typical application point is just prior to discharge of effluent to receiving waters. Allows time for maximum disinfection of effluent Should be where flow is turbulent and short circuiting should not exist, since it requires low time for dechlorination reaction to be finished, contact basins are not needed.it is not feasible to have point of application at the remove location where effluent is discharged to receiving waters since the prime consideration is the removal of chlorine residual.

Reduction of BOD by chlorine

Four types of reactions explain reduction of BOD level by chlorine - direct oxidation -formation with nitrogen compounds of bactericidal chloramines by substitution of chlorine for hydrogen -formation with carbon compounds of substances that are no longer decomposible by substitution of chlorine for hydrogen -addition of chlorine to unsaturated compounds to form nondecomposable substances

Chlorine hazards

Gas 2.5 times heavier than air, corrosive in moist atmospheres and toxic. Must be handled in steel containers and pipinga dn corrosion revisiting mateirals like silver glass Teflon and certain plastics. Chlorine gas at container pressure cannot be piped through teflon silver glass or plastic material. Gas is irritating to mucus membranes of nose throat and lungs, very small percent in the air will cause severe coughing Heavy exposure fatal

Mild exposure

Happens from time to time with chlorination equipment, leaf contaminated area, breathe lightly without exertion, remain calm, keep warm and resist coughing. Notit operators to have them repair leak. If clothing contaminated remove immediately as clothing will give off chlorine gas. Immediately wash off area affected by chlorine If you have slight throat irritation, drink milk. Drinking spirits of peppermint will help reduce throat irration. Mild stimulant like hot tea or coffee can help

What to do in case of a leak occurs

Have prepared emergency plan Handle as rapidly as possible Self contained breathing apparatus is needed buddy system used as well Only authorized employees work on leak Series leak occurs shut off source of sulfur dioxide by closing container valves Turn supply valve off if leak is minor If leak occurs in cylinder then isolate cylinderr from system adn rotate so gas only escapes no liquid. Return damaged tank to supplier as quick as possible Operators cannot transport damaged containers Follow US deraptmetn of transportation regulations Ton tank leaks occur mainly at valves and can be repaired with repair kits Only leaky tank car valve leaks can be repaired others must be returned to manufacterer

Safety with sulfur dioxide

Have regular medical check-up of employees No one with breathing problems heart disorders or disability can work with SO2 Operators must be trained in use fo emergency equipment and procedures and have good physical health to be considered qualified to work with leak And must understand the leak emergency be solved by team of atleast two individuals Establish safety training program to ensure operator works with it can handle it safely

High chlorine residuals and low deamnds

High residuals are demanded b MPN coliform requirements reaching 2.5-12mg/l residuals while wildlife and fish agencies demand dechlorination to .01mg/l which is all fish can normally tolerate

Sleeve cleaning

How often quartz sleeves need to be cleaned is usually result of quality of wastewater treated and treatment chemicals used prior to disinfection. Dipping UV modules for five minutes in suitable cleaning solution will completely remove scale that has deposits on quartz sleeves. Cleaning is best done using inorganic acid solution with pH between 2 and 3 Two most suitable cleaning solutions are nitric acid in strength of 50 percent concentrations and 5 to 10 percent solution of phosphoric acid. Single modules can be removed from channel cleaned, then reinstalled to continue cleaning wile system treats effluent flows

How chlorine treates hydrogen sulfide

Hydrogen sulfide odors increase with temp, but chlorination will inactivate odors, even at levels lower than chlorine demand point Referred to as sub-residual chlorination Odor producing bacteria are reduced in numbers without satisfying chlorine demand as they are apathy of first level reactions. This also is accomplished without interfering with organisms beneficial to treatment process in low doses Quantity needed varies by plant Hydrogen sulfide is in higher concentrations where flow is low Apply chlorine at right location Treatment point should be placed upstream at point where sewer is still under pressure and flowing full thus treatment completed without odors released into atmosphere

Corrective action

If chlorine pressure on system is near or over 100 psi, close supply container valves and stop chlorine addition to system, increase feed rate of chlorinator and use chlorine in system, then drop pressure down to safe range, with alarm system sounding at 110psi -if temp of water is at abnormal level, find cause 185F will actuate Chlorine pressure reducing valve If water is above 200F alarm should have sounded, open contorl switch on evaporator heaters to stop current flow of heating elements, if temp is in normal range, correct original problem of low water level Evaporator water levels are controlled by a solenoid valve, fish check to see if drain valve is fully closed and then -override solenoid valve and fill water bath to proper level, if water cannot be added, take evaporator out of service and switch to another evaporator or switch supply to gas side of container,s may have connect more containers to supply sufficient chlorine gas and repair the valve or actuating sensor

Plugging

If flow to weir is restricted, water level will rise and cuse a backup in tablet feeder, the most common obstacles are leaves or sticks and other solids. Remove when found. Thier is insufficient shearing action by the water to keep slots i feed tubes from becoming obstructed, if they do get obstructed, they need to be cleared as described in maintenance paragraphs or by removing feed tubes from feeder adn clearing obstructing mateirals in the tubes preventing tablets from being mixed with water

Evaporator shut down

If to be turned off for extended period, you should secure the evaporator. In order to do this, shut off the supply to the evaporators while maintaining a vacuum on the unit with sulfonator, once pressure drops to zero, supply line can be disconnected and the dry air line attached to the inlet of the evaporator. This will evacuate the evaporator of residual sulfur dioxide through sulfonator Flush water bath with cold water to remove any foreign material never leave sulfur dioxide trapped in equipment

Special case of tuberculosis hospitals

If you use chlorine in effleunt form a plant serving a tuberculosis hospital, studies have shown that residual of at least 2.0 mg/l should be maintained in effluent from this institution, and that detention time should be atleast 2 hours at average rate of flow instead of 30 minutes Two stage chlorination may be particularly effective in this case The following list of chlorine dosages provide reasonable guidelines to produce chlorine residual adequate for applications indicated for domestic wastewaters Individaul plants may require higher dosages

Piping liquid chlorine

Important to avoid conditions that will encourage vaporization Important liquid chlorine lines are cool or cooler than containers. Avoid running liqui chlorine lines through overheated ares were gasification can take place Valves in liquid chlorine lines should be kept to a minimum. Important to avoid situations where it is easy to close two valves in a line thus trapping liquid which, upon increase in temp may develop dangerous pressures. Use of expansion chamber is recommended where traps occur in the line or where it is necessary to run lies considerable distance. Chamber provides an area of expansion in event claves at both ends of line are closed. Should ahve capacity of least 20 percent of line volume or section fo the line that it protects. Chamber is typically equipped with a rupture disc, pressure gauge, and alarm switch

Liquid chlorine chlorinator start up

In most plants, liquid chlorine is delivered in one ton containers however it can be delivered in railroad tank cars to very large plants - inspect all joints valves manifolds and tubing connections in chlorination system, including application lines for proper fit and for leaks, make sure all joints have gaskets, - if chlorine system has been broken open, verify system is dry, usually once system been dried, it is never opened again to atmosphere. But if moisture in air enters system by other means, ad mixed with chlorine to form hydrochloric acid, pipes valves and joints and fittings will corrode Verify system is dry by determining dew point, if not dry, turn evaporator on pass dry air through system , -start up evaporators fill water bath and adjust device according to manufacturers direction -turn on heaters on evaporators -wait until temp of evaporators reach 180F this may take over hour for large units -inspect and close all valves on chlorine supply line, one chlorine valve on evaporator (inlet valve) should be open to allow expansion of chlorine as it is heated -open chlorine metering orifice slightly by adjusting chlorine feed rate knob, this is to prevent damage to rotometer, -start injector water supply system -examine injector supply system for reading on pressure gauge and reading on vacuum gauge, same as with gas chlorinator set up. -inspect chlorinator vacuum lines for leaks -on system connected to gas side of supply container crack open chlorine gas line at chlorine container all liquid chlorine systems should be checked by using gas because fo danger of leaks (gas less dangerous) inspect joints between valve and next one downstream, if valve passes ammonia test continue all the way down to evaporator, make sure all valves between evaporator and chlorinator are open, heat in evaporator will expand the gas and, if system closed, excessive pressure can develop, chlorine should never be trapped in a line evaporator or chlorinator , after gas test reconnect liquid side and retest connection and pigtail valve -if no problems develop, supply line to evaporator can be put in service by openning the valve 1 1/2 to 2 turns -check operation of chlorinator and operate complete range of chlorine feed rates an manual and automatic settings - if chlorinator is operating properly close gas valve on container, waist a few minutes to evacuate the pigtail connector close valve from the pigtails, to manifold, disconnection for pigtail, replace the gas valve cap remove liquid valve cap adn clean valve face adn treads then install a new gasket to connect the pigtail. Check for a leak at new connection if there is no leak open liquid valve two turns -after admitting liquid chlorine to system wait until temp of evaporator again reaches 180 degrees and full working pressure 100 psi -system is ready for normal operation

Trouble shooting gas liquid and sulfonation systems

In order -page 410 -page 412 -Page 413

Emergency phone call

Include location and instruct where accident took place and where injured can be found

No chlorine in gas flow to chlorinator

Inspect chlorine pressure reducing valve downstream from evaporator and determine if valve is open or closed position -valve may be closed due to low water temp in evaporator -valve may be closed due to loss of Cajun on system or loss of continuity of electrical control circuits, which may have been caused y a momentary power drop, correct problem and reset valve -valve may be out of adjustment and restricting gas flow through the have due to low pressure reading Inspect supply containers and manifold because possible sources of lack of chlorine gas flow to chlorinator could be -containers are empty -chlorine manifold filters plugged, check pressure upstream and downstream from filter, pressure drop should not exceed 10 psi frost on manifold will indicate restriction from filters -inspect manifold and system for closed valves most systems operate properly with all chlorine valves at only one turn open position

Evaporators

Installed where large quantity of chlorine is used Is hot water heater surrounding a steel tank, water is heated by electricity, heat in water is transfered to gas liquid chlorine in inner steel tank, water bath heaters are used to provide even distribution fo heat around tank and elmeinate hot spots. Stopping hot spots prevents danger of overheating chlorine and pressurization of chlorine by expansion and makes evaporator easier to contorl Liquid chlorine containers are connected to it by liquid valve, liquid chlorine vaporizes in evaporator, with gas reaching 110-120F then flows from evaporator to gas manifold, chlorine as manifolds have gas filters to remove small particles from gas

Two areas taht hinder operator ability to meet NPDES coliform requirements

Insufficient chlorine supply -operator fault, you must make sure you have enough on hand with lead time to vendor to supply more by amount you order. Connected containers should not be emptied and sufficient containers are connnected so maximum dosage rates achieved with exceeding max withdrawal rates Weighing scales and automatic switchover equipment should always be provided. Note when switchover occured so empty containers can be replaced with full ones before second set empties Failure of automatic control equipment -manual operation only requires setting Ed rate to correspond with same hour and flow conditions recorded in operator logs Most daily flows are consistent with feed rates known every day of year. Review data for same day or three previous weeks and calculations can be made for intermediate hours 1000-1200 hours to calculate these suggested manual feed rates, determine average feed rate between 900-1100 and between 1100-1300 average fed rates By recording readings of chlorine feed rates, it is simply to manually program equipment and maintain high plant performance during equipment failures,

Monitoring lamp output intensity

Intensity declines with use so operator must watch output intensity to ensure bulbs strong enough to achieve disinfection. Lamp intensity monitors can be installed to monitor level of light output Lamp failure indicators connected to main UV control panel alert operator when lamp burns out and needs replacement

Sodium sulfite hazard

Irritates eyes skin and respiratory system on contact Injection irritates gastro track Large doses cause colic and diarrhea always wash hand when handling Self contained air supply repair kits and chemcial suits must be available to owrk with these chemicals.

Best combination of combined residual chlorine and contact time

Is determined to ensure proper chlorine dose and minimum use fo chlorine to achieve disinfection Changes in pH affect disinfection ability of chlorine and operator must reexamine best combaintion of chlorine addition and contact time when pH fluctuates.

Lamp maintenance

Lampsa re regular components that have to be changed on regular basis. Service life can be from 7500-20000 hours. Three keys to affecting duration of bulbs in lamps would be -level of SS in water to be disinfected, ad fecal coliform level to be achieved. Better quality effluent or less stringent fecal coliform standers require smaller UV doses Since lamps lose intensity with age, the smaller UV dose required the greater drop in lamp output can be accepted -frequency of on off cycles. High cycling rates contribute to lamp electrode failure most common cause. Cycles where the maximum of 4 per 24 hours can considerably prolong lamp life -operating temperature of lamp electrodes, where system temperature usually depends on system conditions. System with both lamp electrodes operating at same temp in water operate up to three times longer tha system where two electrodes operate at different temperatures. This can occur because only one electrode is immersed in water and other is surrounded by air if air temperature is routinely higher than water temp Largest drop in lamp output occurs during first 7500 hours and decrease is usually around 30-40 percent thereafter annual decrease in lamp output is around 5-10 percent and is caused by decreased volume of gases within lamps and by compositional alteration of quartz solarization. Which makes it more opaque to the light

Proper chlorinator feed rate settings hould be determined by schedule

Large plants- every hour Medium sized plant- 2-4 hours Small plants - every 8 hours

Larger vs smaller systems hypochlorinators

Larger systems use liquid chlorine because of lower costs Some large cities however use hypochlorite because it is safer Plants in these cities are located in highly populated areas where escaping chlorine gas could harm people

Safety with UV lamps

Light from UV lamp can burn eyes and skin Never look into uncovers parts of UV chamber without glasses Do not plug UV unit into electrical outlet or switch without having UV lamps properly secured in UV water chamber and box closed Up lamps contain mercury vapor very hazardous if lamp is broken.

UV light intensity effectiveness

Light intensity reaching pathogens is affected by condition of UV lamps and qualtiy of wastewater UV unit adjusts UV dose according to light transmission and effluent flow Up lamp conditon is affected by age and amount of slime on surface UV unit will periodically clean lamps by mechanical means Operators adjust frequency and number of wiping cycles of the cleaning process UV lights can be cleaned manually in tanks containing chemcial solution as well too Upstream process affect quality of wastewater as well affecting UV light effectiveness. Total suspended solids affect turbidity in water and inhibits light transmission through the water Also shields bacteria and protects them from UV radiation, Low UV light intensity will produce low level of disinfection Lamps must be replaced when output at maximum power is insufficient to disinfect

Types of UV systems

Low pressure mercury vapor UV lamps are usually source of UV radiation Lamp assemblies are mounted on rack and immersed in flowing water with lamps protected y quartz sleeve adn watertight electrical connections. Most UV installations in America use open channel configurations Placed normally horizontal or parallel with flow Or vertical dn perpendicular to flow 16 lamps could be 3 inches apart to provide disinfection for wter flowing 48 inch deep channel Number of Uv banks per channel is determined by required UV dosage to achieve target effluent quality. In vertical nd perpendicular flow lamp configurations, vertical lamp module has stainless reel support frame that can be removed from channel for cleaning Each lamp can be removed from frame without removing entire module from channel Length of UV lamps establishes depth of water in channel UV lamps can be installed in closed pressure vessels when maintaining pressure in water transmission system is needed Another type of system is thin film type, using chamber with many lamps spaced one quarter inch apart and has been used in wastewater industry for 9 MGD secondary treatment Sometimes you can encounter Teflon tube UV disinfection system Not in common use, but water flows in thin walled teflon cube past a series of UV lamps with light penetrates teflon tube and is absorbed by fluid. Advantage is taht water never comes in contact with lamps However scale does eventually build up on pipe walls and must be removed or teflon tube is repacked

Solution discharge lines

Made from variety of materials, depending on requirement of service, two primary requirements are line must be resistant to corrosive effects of chlorine and adequate in size to carry required flows Also consider pressure conditions flexibility resistance to external corrosion and stresses when underground or passing through structures, easiness of connections, and adaptability to field fabrication or alteration PVC pipe and black polyethylene flexible tubing have eliminated most rubber hose Generally less expensive and both outlast rubber in normal service. Rubber hose is still used exclusively for applications that require flexibility when extremely high back pressures exist NEVER USE NEOPRENE HOSE IT BECOMES HARD AND BRITTLE QUICK FROM CHLORINE

Determining residual sulfur dioxide

Measured to be sure sulfonator is not overdosing and wasting sulfur dioxide Residual of .5mg/l or less is ideal Aquatic life can withstand residuals of 20mg/l or less Method for sulfur dioxide residual is similar to determining chlorine residual Uses amperometric titration procedure

Injector

Merely aspirator that creates a vacuum in low pressure are of the barrel Regulated by orifice opening and water flowing through the throat of the aspirator At injector, sulfur dioxide gas dissolves in water to form sulfuric acid then flows to point of injection Sulfur dioxide flows from storage supply to sulfonator, then into metering device, then injector

Sulfur dioxide in wastewater

Mixing of SO2 with wastewater converts all active positive chlorine ions to nonactive negative chloride ions Produces sulfurous acid ion and hydrogen ion , which is sulfuric acid Formation of sulfuric acid si not harmful neither is hydrochloric acid produced because it is small amount When combined with chloramines, reaction forms ammonium hydrogen sulfideand hydrochloric acid, and similar products are made with dichloramine and nitrogen trichloride Organic mateirals present may cause reaction rate to change so excess sulfur dioxide may have to be applied. Excess sulfur dioxide dosages should be avoided as they are wasteful and may result in dissolved oxygen reduction with increases in BOD and COD and drop in pH of effluent discharged Chemcial reaction between sulfur dioxide and chlorine is one to one. You can substitute sodium sulfite or sodium metabisulfite, if it is desirable to not use sulfur dioxide for safety reasons, as gas sulfur dioxide can be toxic. Sodium sulfite reactions require 1.78 pounds of pur sodium sulfite per pound of chlorien Both these alternatives require sodium sulfite and sodium metabisulfite require liquid storage tanks and feed pumps. Evaporators are not needed and sodium sulfite is available as dry chemcial in tablet form

Typical installation of redox chlorine controller

Monitors chlorine residual using redox probe suspended in chlorine contact chamber approximately 6.5 minutes downstream from injection point Controller converts redox signal to 4-0 milk amp signal taht adjusts chlorine feed rate from chlorinator. Second high resolution redox probe is suspened approximately 4 minutes downstream from point of sulfur dioxide (used to chlorinate downstream) injection, and send signal to second controller to adjust sulfur dioxide feed from sulfonator

Sulfur dioxide

Most popular chemcial treatment method because it uses existing chlorination equipment and makes extensive training unnecessary. It is colorless gas with pungent sharp biting odor. SO2 may be cooled and compressed to liquid. When gas is compressed to liquid colorless liquid is formed. When in closed container, similar to chlorine, normally liquid and gas are in equilibrium Pressure in container bears definite relation to temperature Sulfur dioxide is not flammable or explosive in either form gas or fluid, dry gas is not corrosive to most metals, but in moisture becomes sulfuric acid and is extremely corrosive Similar storage and equipment is used for SO2 as chlorine Sulfonators are designed different form equipment for chlorine to specifically handle sulfur dioxide. More soluble in water than chlorine, one pound per gallon can be absorbed at 60F and as temp increase as sulfur dioxide solubility decreases and when dissolved in water, forms weak solution of sulfuric acid. Density of SO2 is similar to chlorine Can use chlorine rotameter to measure flow of sulfur dioxide gas without much difficulty multiple chlorine reading by .95 to obtain pounds per day of sulfur dioxide used

Ton tanks

Must be placed on sides with valves in verticle position. Connect flexible tubing to top valve to remove chlorine gas from tank. Bottom valve is used to remove liquid chlorine and used only with chlorine evaporator. Valves are simliar to those on smaller chlorine cylinders without fusible plugs present.

Chlorine leaks

Must be taken care of immediately Corrective measure should be taken only by trainers wearing proper safety equipment All persons should leave the danger area until conditions are asafe If leak is large all persons in the adjacent areas should be warned and evacuated. Obtain assistance from off site emergency response agencies.you must consider your neighbors people animals and plants

Nitrite lock occurs cause

Nitrification not complete Ammonia is oxidized to nitrite, but nitrite not oxidized to nitrate, occurs when nitrobacter population has not become established, such as during start up of nitrification system or when nitrobacter is inhibited. Free chlorien will react with nitrite at a 5 to 1 ratio, and chloramines do not readily react with nitrite

Chlorine solution diffusers

Normally constructed same materials as solution ines Design is extremely important for chlorination program Completely related to mixing of chlorine solution with water being treated Strength and flexibility of diffuser is considered as well. Usually at .25 ft per second flows , solution is injected at center of pipeline will mix with entire flow after flowing ten pipe diameters downstream Mixing in open channels can be accomplished by hydraulic pump use, or by sizing diffuser orifice so higher elicits like 16ft per second is attained at diffuser discharge. This can accomplish two things, introduce a pressure drop to equal discharge from each orifice, and impart suffcient energy to surrounding water to complete mixing. Diffusers are supplied every two to three feet of channel depth and dplaced across width of channel rather than in direction fo flow Mixers are also used to achieve Mixing

Evaporator in sulfonation systems

Nothing more than heating system designed to increase temp of liquid sulfur dioxide to point of being gas liquid sulfur dioxide is piped from source to evaporator, tank is immersed in constant temperature hot water bath Water in bath is heated to 180F this heat converts liquid to gas. Liquid sulfur dioxide enters evaporator at bottom and gas leaves from the top. Gas and liquid are almost in equilibrium due to design and implementation of equipment

Piping chlorine gas

Observe correct temp conditions avoid difficulty with reliquefaction of chlorine piping and control equipment should be at higher them than chlorine containers. Preferable to run chlorine gas lines overhead through warm areas rather than along floor or through basement areas that are lower temp If not possible to secure suitable temp, use external chlorine pressure reducing valve near containers is recommended. Use of pressure reducing valve dis also recommended in those localities were severe temp changes are likely encountered in 24 hour timeframe

quartz sleeve fouling

Occurs when cations such as calcium iron or aluminum ions attach to protien and colloidal matter that crystallizes on quartz sleeves. This coating builds up to point where buildup has to be removed for system to remain effective Rate of fouling of quartz sleeves occurs depending on items like -types of treatment process prior to UV disinfection -Quality of water being treated -chemcials used in treatment process -length of time lamps are submerged -velocity of water through UV system very low or stagnant flows are especially likely to permit setting of solids and result fouling problems

Break point chlorination problem

Occurs when chlorine to ammonia ratio exceeds 8-1 When ratio exceeded chlorine will oxidize ammonia to nitrate or other end products The options for operator are twofold, increase chlorine concentration until breakpoint is reached, or decrease concentration until teh chlorine ammonia ratio is below 5-1, second option is recommended but tough call for operator s since reducing chlorien feed when you do not have a residual seems nonsensical

H2 S problems

Odor nuisance, explosive in right mixture, hazardous to sense of smell, and paralyze respiratory center Corrosion of metals, concrete and damage to electrical equipment Found in any collection and treatment system with sufficient time to allow its development, expected to be present often in new systems were flows are extremely low in comparison with design capacity. Specially in lift stations where pump operating cycles may be low frequency.

Connections for containers

Outlet threads of container valves are unique and not ordinary tapered pipe threads Use only fittings and gaskets built for these valves. Always use new gasket for changing fittings. Inspect container valves.inspect connecting nut on chlorine system Yoke type connectors are recommended

ORP

Oxidation reduction potential probs are used to optimize chlorination process in water treatment plant s Also called redox potential, is direct measurement of effectiveness of chlorine residual in disinfecting plant effluent Chlorine is missing one or more electrons they tend to take electrons from any organic substance or microorganisms present in water being treated, when coliform microorganisms lose electrons they become inactivated adn can no longer transmit disease or reproduce Ability of chlorine to take elctrons is the ORP and is measurable in millivolts, strength of redox measurement is directly proportiaonl to oxidative disinfection strength of chlorine in system. Higher teh concentration of organics in water, lower the ORP voltage because more substances need to be nuetralized by same amount of chlorine, thus less effective disinfection is achieved as not enough chlorine is present to take elctrons from all the organisms in a high laod Redox sensing unit or probe measures voltage present in waterstream being treated and thus provides direct measure of disinfecting power of disinfectant in stream

Advantages of ozone

Ozone is more effective than chlorine in destroying virus and bacteria -uses shorter contact time -no harmful residuals -no regrowth of organisms except those protected by particulates in wastewater effleunt -ozone is generated on site so less safety problems associated with transportation and handling

Disinfection with ozone systems

Ozone is produced when oxygen is exposed ot energy source and converted to unstable gas ozone O3 Very strong oxidant and virucide Generally on site because it is unstable and decomposes so made in house Effectiveness of ozone depends on susceptibility of target ozone Ozone is fed into down flow contact chamber contacting wastewater Purpose of chamber is to transfer ozone from gas bubble while providing sufficient contact time. Must be exposed to wastewater uniformly in plug flow type contactor Guidelines for ozone process control are dosing mixing and contact time Strives for maximum solubility of ozone in wastewater as disinfection depends on transfer of ozone in wastewater Amount of ozone above water or in gas feed system is dependent on ozone being dissolved in water at constant temperature as function of partial pressure of gaseous ozone above water All ozone systems should be pilot tested and calibrated prior to installation to ensure they meet discharge permit requirements

Application and dosage ranges for chlorine in collection systems, treatment, activated sludge, digester, and for disinfection chart

Page 353

Sulfur dioxide feed system sizes table

Page 406

Amperometric titration sulfur dioxide residual procedure

Page 408 Excess iodine measures sulfur dioxide present in sample and absence of amperometric titration, starch and color change from clear to blue may be substituted at end point of procedure

UV disinfection system calculations

Page 420

Guidelines for recommended UV lamp cleaing methods

Page 423

Troubleshooting chlorinator problems

Pages 369-373

Parasitic

Parasitic bacteria are those bacteria that normally live off another living organism known as host

Why disinfection is effective

Pathogenic microorganisms are more sensitive to chlorine than non-pathogens

Wiping system routine tasks

Periodically observe wiping system process to ensure operation of wiping action of a bank and proper wiping cycle. Action of wiping in bank is operated on regular timed basis in following manner -wiping solenoid energized -wiper rings reach far end -wiping solenoid is deenergized -system waits until all wipers in bank reach the rest end before repeating cycle in next bank. - if wipers do not complete cycle in one minute, an alarm goes off generated and system goes on to next bank -once al the banks have been wiped, wipe counter is incremented and cycle resets to first bank again -the cycle is repeated until the wipe counter number of wipes exceeds the pre-set valve wiping sequencing is complete Carried out irrespectively of operational status of bank however must be in position and submerged in water zone.

Ultraviolet

Pertaining to band of electromagnetic radiation just beyond the visible light spectrum. Ultraviolet radiation is used in wastewater treatment to disinfect the water, when ultraviolet radiation is absorbed by the cells of microorganisms, it damaged the genetic material in such a way that the organisms are no longer able to grow or reproduce, thus ultimately killing them

Tablet dechlorination unit

Placed in unit, capacity of unit is based on flow and sodium sulfite requirements They can trea twice thier rated flow capacity for short term peak flows Installed at effluent from chlorine contact basin to discharge line Unit should be level and drain completely at low flow or no flow conditions The outlet of feeder should allow wastewater to free fall to not cause a flow back into unit Effluent should be tested for chlorine after dechlorination t ensure no chlorine enters receiving waters through starch iodine test System must be adjusted to provide required sodium sulfite dosage, accomplished by selecting weir fo proper size and determine the number of tubes to be filled with tablets Admit entire flow adn then operation is continous and automatic After one hour, samples should be taken at the inlet and outlet of dechlorination system. Inlet sample should be analyzed for residual chlorine adn outlet sample for residual chlorine and sulfite Take multiple samples from inlet adn outlet system during first few days of operation as system will need to be fine tuned. Will reducing residual sulfite to maintain 100 percent dechlorination Minimizing sulfite stops excess tablet use and reduces effect on DO and pH of effleunt Change weir size adn configuration of tubes to adjust system

Breakout of chlorine (chlorine breakaway)

Point at which chlorine leaves solution as a gas because chlorine feed rate is too high solution is saturated and cannot dissolve any more chlorine. Maximum strength fo chlorine solution can attain is approximately 3500 mg/l beyond this concentration molecular chlorine will break out of solution and cause off-gassing at point of application

Chlorine and sedimentation and grease removal

Prechlorination in inlet of settling tank improve clarification and settling rate, reducing septicity of raw wastewater, and increasing grease removal Maximum grease removal achieved when chlorination in the range of one to 10 mg/l done Grease removal is beneficial side effect, but mainly prechloration accomplishes improved settling rate

Part and purpose chlorinator

Pressure gauge - indicators chlorine pressure at chloraitor system from chlorine manifold and supply 20 psi minimum Gas supply- provides source of chlorine ga from contacted to chlorinator system Vacuum regulator check unit- maintains constant vacuum on chlorinator Standby pressure relief -relieves excess gas pressure Vent-discharges excess chlorine gas to atmosphere outside of chlorination building Gas inlet- allows entrance fo chlorine gas to chlorinator, gas flows from container through supply lie and gas manifold to inlet Heater - prevents reliquefaction of chlorine gas Vacuum gauge- indicates vacuum on chlorinator system Rotameter tube and float - indicate chlorinator feed rate by reading top of float or center of ball for rate marked on tube Differential regulating valve - regulates chlorinator chlorine gas pressure, serves to maintain a constant differential across orifice to obtain repeatable chlorine gas flow rates at given V notch orifice opening regardless of injector vacuum fluctautions V notch plug and variable orifice - control chlorine feed rate by regulating flow fo chlorine gas through wide V notch in the plug that allows high feed rebates through orifice and small V for slow rates Vacuum relief valve-relieves excess vacuum by allowing air to enter system and reduce vacuum Vacuum relief - provides source of air to reduce excess vacuum Injector vacuum gauge -indicates vacuum at the injector Diaphragm check valve - regulates chloraitor vacuum which in turn adjusts chlorinator feed rate, Recieves signal form chlorine feed rate controls and then adjusts feed rates by regulating vacuum Manual feed rate adjuster - regulates chlorine feed rate manually, serves as manual override of automatic contorls Injector water supply - provides source fo water for chlorine solution to mix with, must provide sufficient pressure and volume to operate injector Injector - mixes or injects chlorine gas into water creates sufficient vacuum to operate chlorinator and pull metered amount of chlorine gas Solution discharge - discharges solution mixture of chlorine and water

Benefit of up sewer chlorination

Prevent deterioration of structures Also aids odor and septicity control, and possibly BOD reduction to decrease load imposed on treatment plant A single application of chlorine at a point on main intercepting sewer before junction of all feeder sewer lines may yield best benefit Sometimes more tahn one point on main intercepting sewer line exposure may be better Chlorination is considered temporary or emergency measure in most cases due to cost of maintaining supply Aeration is also a method that can control septic conditions in collection system

Main objective of disinfection

Prevent spread of disease by protecting -public water supply -recieving waters used for recreational purposes -shellfish growing areas

Need for dechlorination

Protect environment and aquatic wildlife from toxic chlorine no chlorine residual is allowed into effluent reaching recieving waters

Pump flow Million gallons per day formula

Pump flow (MGD) = Pump flow (gallons per day) X 60 (minutes/hour) X 24 (Hours/day)

Air padding

Pumping dry air (dew point -40F) into container to assist with withdrawal of liquid or to force liquified gas such as chlorine or sulfur dioxide out of the container

Dechlorination tablet feeder maintenance

Refilling feed tubes on occasion and cleaning the tablet feeder are required to be done Occasiaonl cleaning of feeder to remove accumulated residues should be done every 6-12 weeks.

First aid response

Remove person from contaminated area and wash affected parts of body with ater Cloths affected be removed and washed thoroughly If burned, get medical attention from doctor Keep individual warm with head and shoulders elevated Asphyxiation, rare due to pungent odor fo sulfur dioxide perform CPR if they arent breathing , someone should call fire department to get expert help Eyes, wash immediately with large amount sof water for 15 minutes from hose or wash facility Skin, wash off with large amount fo water adn remove cloths contaminated Ingestion, if ingested drink water induce vomiting and sneak attention immediately

Operator tasks

Requires little operator attention Prevent short circuiting and insure all microorganisms recieve suffcient exposure to UV light Water level over lamps must be maintained at right level and water levels in channels can be controlled by weirs or automatic control tastes

Normal operation of chlorination proces

Requires regular observation of facility and regular preventative maintenance program

Specified chlorine residual levels required at some point down stream

Residual analyzer should be used to monitor and record residual at this point, can also be used to change the control set point of controlling residual analyzer

Reliquefaction

Return of a gas to the liquid state, for exampe a condensation of chlorine gas to return it to its liquid form by cooling

Sulfonator gauges should be checked

Rotameter- indicates dosage rage of sulfur dioxide and can be set manually or automatically. Should read the same as the established feed rate Gas pressure- normally 20-30 psi -injector suction, check if unit fluctuates a lot if it does injector water supply should be inspected for cause Procedures and equipment for operating and maintaining chlorination and sulfonation systems are very similar however you should be aware of differences -sulfonator control valve diaphragms are made from different material to handle sulfur dioxide but they may be used for chlorine, reverse is not true, chlorinator control valve diaphragms cannot be used for sulfur dioxide -chlorinators used as sulfonators cannot deliver the full rated capacity of sulfur dioxide. Chlorinator rated to deliver 2000 pounds of chlorine per day can only deliver 1900 pounds of sulfur dioxide per day. Chlorinator rated for 10000 pounds chlorine can only deliver 8000 pounds of sulfur dioxide per day -sulfur dioxide gas pressures from sulfur dioxide containers are lower than chlorine gas pressures at the same temperature. So2 does not vaporize at the same rate as chlorine at the same temperature. Therefore SO2 containers are occasionally padded on the gas side with nitrogen to force liquid sulfur dioxide from a container to the evaporator. Consequently reliquefaction sometimes is a problem in the supply line between evaporator and sulfonator

Sulfonator feed rate formula for manual operation

Safety factor of 3.0 mg/l of sulfur dioxide is more than the chlorine residual is applied Changes with experience to be reduced to level actually needed. Feed rate of sulfur dioxide in lbs/day= Flow MGD x Dose mg/l X8.34 lbs/gallon

Sulfur dioxide containers

Same as chlorine Two differences between use of chlorine and sulfur dioxide -withdrawal rates of sulfur dioxide from containers are slightly lower than rates for chlorine -valves in sulfur dioxide system should be made of 316 stainless steel with Teflon seats

Sulfur dioxide safety program

Same as other safety program list with phone number of people to call -establishes procedures on how to make emergency phone call Participate in periodic training incldiuign hands on use of safety equipment and safety procedures Like how to use and maintenance leak detection equipment, leak repair equipment, respiratory protective equipment , atmospheric monitoring devices, -establishes emergency procedure for chemical leaks and first aid -establish a maintenance and calibration program for safety devices and equipment

Supply piping

Same as required for chlorine Not corrosive to most metals when dry but in reality SO2 gas is never completely dry Use schedule 80 seamless carbon steel pipe with 3000 pound forged steel fittings avoid use of bushing by using reducing fitting instead All unions should be of The ammonia type with lead gasket joints never use ground joint unions Plastic material has been used to connect sulfonators to source of supply Ideally suited for carrying sulfur dioxide solution to point of application Piping system carrying sulfur dioxide gas should be heated to room temp and kept at 80-90F to prevent reliquefaction

Operational strategy

Schedule when maintenance will be done when demands on chlorination system are low like winter months Maintenance of chlorination facilities require disassembly cleaning repairing and reassembling done during winter months november through April Standby capability should be available when equipment fail Needed for atleast post chlorination Supply of HTH should be available in emergencies to be fed manually while repairs are made

Emergency safety equipment

Self contained pressure demand air breathing apparatus used Cannot be stored in room with chlorine or sulfur dioxide equipment Should have its own air or oxygen supply Two types, one contains 30 mins air used by fire department but are adaptable to air line system equipped with 150 psi compressed breathable air cylinder that affords 4 hours of air Second is canister to manufacture oxygen and is completely self contained called rebreather kit Pressure demand units are safer

Chlorinator injector water supply

Serves to produce vacuum under which vacuum chlorinators function to dissolve the chlorine and discharge it as solution at point of application, quantity of water required ad pressure needed depends on -maximum chlorinator feed rate -back pressure at injector discharge (pressure from point of chlorine application, plus friction loss in solution line, and added or subtracted in elevation differences between injector and point of application Water quantity and pressure can vary from two GPM at 15 psi for 10 lbs a day or 0 psi back pressure and up to 260 GMP at 60 psi or 8000 lbs per day at 20 psi back pressure In extreme high pressure scenarios, injector water up to 300 psi may be required, these conditions do not occur frequently in wastewater treatment installationsa nd back pressures exceeding 0 psi are uncommon Plant effluent is used frequently as chlorinator injector water supply, pump is usually required to provide required quantity and pressure. Pump is used exclusively for injector operation, should be designed for 25-50 percent over capacity to allow for wear. Injector water is often supplied from service water system also providing water for other purpose If only using potable water as supply, precautions must be made to not allow direct cross connections between wastewater and potable water to prevent contamination Injector water requirements vary widely depending on make model capacity and back pressure It is advised to consult the chlorinator manufacturer if new system is to be installed or if an existing system must be altered any any of these operating conditions would change.

PVC and polyethnyline

Should be field fabricated and altered, PVC should be schedule 80 to limit its tendency to partially collapse under vacuum conditions Can be threaded and assembled with ordinary pipe tools or may be installed using solvent welded fittings

Selection of control methods

Should depend on treatment costs and treatment results Waste dischargers must meet a disinfection standard a small plant can do this with compound loop control system costing several thousand dollars, but may save less than hundred dollars a year in chlorine consumed, in this case expense is not justified Smaller plants may use manual system that would meet maximum requirements and overhchlorinate at minimum requirement levels. Sometimes plants have maximum chlorine residual requirements due to water being used in irrigation or marine life tolerances are at play, so uncontrolled or haphazard application of chlorine cannot be considered, and no matter how large the added cost is

Sulfonator

Similar to chlorinator, except orifice and rotameter are different ad housing and diaphragms are manufactured to handle SO2 rather than chlorine Sulfonator is the sulfur dioxide gas metering device

Connections at chlorinator

Small chlorinators are equipped to recieve flexible connection directly from chlorine containers and no other piping necessary. Large chlorinators may need flexible connection from manifold,

Plant chlorination

Specific point of application of chlorine depends on results desired. Purpose of plant chlorination may be to control and prevent odors, corrosion, slduge bulking, digester foaming, filter ponding filter flies , and aid in sludge thickening. Usually reserved as an emergency measure to aid in these things Can interfere with or inhibit biological treatment processes

Connections at containers

Standard practice is connect auxiliary tank valve to container valve to facilitate changing containers Serves as shutoff valve inevent container valve is defective. Flexible connection is used to connect to manifold or in small installations, directly to chlorinator

Sulfonator maintenance

Sulfonator should be cleaned very year or more frequently Manufacturers cleaning procedure followed Never use old worn parts Record maintenance and repairs done

Sulfur dioxide hazard

Sulfur dioxide is extremely hazardous and must be handled with caution. Exercise extreme caution when working tih it, never work alone on sulfur dioxide lea, use buddy system,and wear self contained breathing apparatus in leak Request emergency assistance and be prepared with organized plan Sulfur dioxide has strong pungent odor, if you smell it, tell supervisor and get help If you inhale sulfur dioxide gas, sulfurous acid will form on moist membranes in body adn causes severer irritation or more serious harm. Greater the exposure to high doses of sulfur dioxide can cause death due to lack of oxygen. Chemcial bronchopneumonia with severe bronchiole this may be fatal several days later, in event it is inhaled, bring victim to fresh air, use CPR if necessary, and contact a doctor. Settles in lower areas and has low vapor pressure meaning liquid changes quickly from gas when liberated

Chlorine dose

Sum of chlorine residual added with chlorine demand

Effects of chlorine by concentration of chlorine gas

Table 10.2 376

Sodium sulfite supply and safety

Tables used for dechlorination are available in 45 pound plastic buckets Must be dry and tightly closed container when not in use Store in cool dry place away from acids or oxidizers Flush away small spills of dust or powder with water Shaved up material for disposal in accordance with MSDS in case of a moderate size spill and in fire, flood with water do not reuse empty containers Maintain a shelf life and table strength store at temps of 85F

Postchlorination

The addition of chlorine to the plant discharge or effluent, following plant treatment, for disinfection purposes.

Combined residual chlorination

The application of chlorine to water or wastewater to produce a combined available chlorine residual. The residual may consist of chlorine compounds formed by the reaction of chlorine with natural or added ammonia (NH3) or with certain organic nitrogen compounds.

Residual chlorine

The concentration of chlorine present in water after the chlorine demand has been satisfied. The concentration is expressed in terms of the total chlorine residual, which includes both the free and combined or chemically bound chlorine residuals.

Chlorine residual

The concentration of chlorine present in water after the chlorine demand has been satisfied. The concentration is expressed in terms of total chlorine residual, which includes both the free and combined or chemically bound chlorine residual. Also called residual chlorine

Manual contorl

The feed rate adjustment and starting and stopping of equipment by hand

Combined chlorine

The sum of the chlorine species composed of free chlorine and ammonia, including monochloramine, dichloramine, and trichloramine (nitrogen trichloride). Dichloramine is the strongest disinfectant of these chlorine species, but it has less oxidative capacity than free chlorine.

Mixing

Throrough mixing of chlorine solution with water is needed for ideal results in effective disinfection. Mixing and speed of mixing are important ahead of a chlorine contact tank or residual sampling point. Since contact tank is designed for low velocity, little mixing occurs after water enters it, can also be achieved before contact tank is entered, same is true for chlorine residual point. Erratic results from sampling occur if good mixing is not done upstream of point for residual chlorine analyzing system implementation.

Titrate

To titrate a sample, a chemical solution of known strength is added drop by drop until a certain color change, precipitate, or pH change in the sample is observed (end point). Titration is the process of adding the chemical reagent in small increments (0.1-1.0 milliliter) until completion of the reaction, as signaled by the end point.

Ballast

Type of transformer that is used to limit current in UV lamp They are arc discharging devices, more current in arc lower the resistance becomes Lamp would destroy itself without one

Biofilms on UV channel walls and equipment

Typically fungal and filamentous bacteria that develop on exposed surfaces and are especially troublesome in areas exposed to light. When biofilms work as shields for bacteria, and they can break away from surfaces, and protect bacteria in clumps as they pass through UV disinfection system Operators must periodically remove biofilms using hypochlorite disinfection solution

Cleaning tank

UV bulbs can be cleaned in acid bath in cleaning tank If module removed from a bank the rest of modules in bank will be turned off

Emergency alarms

UV inlet level high Inlet turbidity high Sample flow low Inlet gate motorized gate control failure Inlet channel high transmittance Inlet channel low transmittance Diversion gate failure Isolation gate failure Inlet gate failure System flow rates Unit power failure Channels inlet gates failure Channel level sensor low/high Channel level sensor low/low Low dose

Effectiveness of disinfection is

Ultimate team measure of bacteriological result of disinfection Measurement of residual chlorine does supply a tool for practical contorl If residual chlorine valve commonly effective in most treatments plants does not yield satisfactory bacteria kills in particular plant, the residual chlorine that does must be determined and used as control in that plant Generally, .5 mg/l residual chlorine is the right amount, but is just a guide taht may be changed by local requirements

Railroad tank cars

Unloading tank cars performed by trained personnel with established safety procedures Follow procedures to recieve connect and disconnect railroad tank cars

Insufficient does or incomplete removal of chlorine

Use additional feed tube or smaller size weir If feed tubes are not touching bottom of tablet feeder, an insufficient dose will occur If Improperly loaded the tablets can jam, causing stack to remain suspended above water level A hard rap on tube will loosen bound tablets Gross hydraulic overload will cause desired sulfite use to lower and need more Nothing should be changed if this is the case, but if overload into plant becomes permanent then additional feed tubes should be put into service to achieve desired sulfite level.

Piping materials and joints

Use of seamless carbon steel schedule 80 pipe for conducting chlorine gas or liquid and fittings that are 3000 lb forged steel size be 3/4 to inch in most installations, it will be practical to use threaded joints. Joints should be put together using teflon tape as joint lubricant. Unions of flanged ammonia type two bolt oval are recommended for pipe size larger than one inch in diameter. Line valves should be kept to a minimum. Insulation is required only in those unusual cases where it is necessary to prevent chlorine gas lines from becoming chilled or liquid lines from becoming overheated.

Hypochlorinator feed rate and control

Used for disinfection primarily Hupochlorite compounds have useful chlorine concentrations lower than concentration in pure gaseous or liquid chlorine and genrally more expensive per unit of chlorine., safety storage and application equipment costs and training costs for hypochlorite usage can be much lower in small plants and hypochlorite use is often cost effective when all additive costs are considered. Amount of chlorine delivered depends on type of hypochlorite, HTH or high test hypochlorite contains approximately 65 percent chlorine by wate, and chlorinated lime contains only 34 percent.

Evaporators

Used to convert liquid chlorine to gaseous chlorine for use by gas chlorinator

Rubber line steel pipe

Used where resistance to external stresses are required, it cannot be field fabricated or altered and is thus somewhat restricted in application PVC lining of steel pipe is not economically competitive, but other plastics are competing with rubber lining and are adaptable to field fabrication

Hypochlorination and wastewater

Usually not most effective method of disinfection Higher costs and disinfecting deficiencies of hypochlorination make chlorination with liquid or gaseous chlorine more effective method in most cases Safer than gaseous chlorination, and some cities switch to using this instead for that reason. When pH increased, hypochlorite ion formation is increased, and is less efficient than hypochlorous acid in disinfecting, but hypochlorite solution is added to wastewater, solution becomes diluted, with pH usually approaching pH of wastewater. Hypochlorination will raise pH of wastewater being treated, the rise in pH will decrease effectiveness of hypochlorite, thereby requiring a higher dosage to achieve disinfection. And this increases pH even more

Sodium chlorite

Usually supplied as salt and require special considerations. Very combustible around organic compounds, must be neutralized with anhydrous sodium sulfite, combustible clothing like gloves should not be worn when handling sodium chlorite. If ones into contact with clothing, cloths must be removed and soaked in water to remove all traces of sodium chlorite or be burned immediately, Chlorine dioxide has not been widely used to treat wastewater due to risks of sodium chlorite.

Safety in evaporators and destination of chlorine gasified in evaporator

When temp fo water one evaporator reaches set level, valves open or close to allow chlorine gas to flow into chlorinators, if temp drops, then valves close to prevent liquid chlorine entering chlorinator Level of liquid chlorine in evaporator tank is regulated automatically by pressure from chlorination system demand for chlorine. When chlorine demand is high, pressure at liquid chlorine supply confidants exceeds evaporator gas pressure and liquid chlorine flows from inner tank, and when demand decreases, evaporators inner tank pressure increases resolving pull on liquid chlorine containers Equilibrium is met when liquid flow rate and rate of vaporization is equal Chlorine leaves evaporator and enters gas pressure reducing valve, then enters inlet block of chlorinator, chlorinator meters gas at desired dosage rate to injector, a heater at chlorinator inlet block vaporizes any liquid droplets that may have carried from evaporator. Keep chlorinator 10F warmer than storage or evaporator room to prevent reliquefaction.

Compound loop control

Any automatic control system (step rate timed program, flow proportional, or chlorine residual, can be used in two ways. -positioning feed rate valve - by varying the vacuum differential across feed rate valve Changes in flow cause changes in feed rate valve position, but changes in chlorine demand may occur without flow cahnge, when this happens, a residual analyzer detects a change in chlorine residual adn by varying vacuum differential across feed rate valve, causes chlorinator to change rates to meet desired chlorine residual Various combinations of compound loop control can be devised Fastes response part of system should be applied to valve positioning since it responds faster, if flow changes are rapid, flow contorl should be by valve position, if flow and demand changes rates are nearly the same, magnitude of change may dictate the selection of contorl

Breakpoint for chlorine in wastewater

Approximately 25-150 mg/l

MPN

most probable number of coliform group organisms

Chlorine requirements

quantiy of chlorine demanding substances differ from plant to plant so amount of chlorine needed to ensure disinfection differs amount of chlorine required to satisfy chlorine demanding substances is called chlorine demand Demand is equal to chlorine dose minus chlorine residual

Biodegradation

the breaking down of dead organic matter by living organisms such as bacteria

Amperometric

A method of measurement that records electric current flowing or generated, rather than recording voltage. Amperometric titration is a means of measuring concentrations of certain substances in water.

Disinfection

A process that eliminates many or all microorganisms, with the exception of bacteria spores, from inanimate objects Process designed to kill or inactivate most microorganisms in water or wastewater including essentially all pathogenic bacteria, there are several ways to disinfect with chlorination being most frequently used in water and water plants, compare with sterilization

Reagent

A pure chemical substance that is used to make new products or is used in chemical tests to measure, detect, or examine other substances.

Internal parasite illness

Amoebic dysentery Ascariasis Cryptosporidiosis Giardiasis

Sacrificial anode

An easily corroded material deliberately installed in a pipe or tank, the intent of such an installation is to give up anode to corrrosion while water supply facilities remain relatively corrosion free

Air gap

An open, vertical drop, or vertical empty space, between a drinking (potable) water supply and potentially contaminated water. This gap prevents the contamination of drinking water by backsiphonage because there is no way potentially contaminated water can reach the drinking water supply.

Bacteria caused illness

Anthrax Bacillary dysentery Cholera Gastroenteritis Leptospirosis

Reducing agent

Any substance such as base metal (iron) or sulfide ion (S2-) that will readily donate electrons the opposite is an oxidizing agent

Oxidizing agent

Any substance, such as oxygen or chlorine that will readily add (take on) electrons. When oxygen or chlorine is added to water or wastewater, organic substances are oxidized, these oxidized organic substances are more stable and less likely to give off odors or contain disease causing bacteria

Hypochlorination

Application of hypochlorite compounds to water or wastewater for the purpose of disinfection

Ozonation

Application of ozone in water wastewater or air, genrally for the purpose of disinfection or odor control

Chlorine in wastewater

Applied to wastewater as free chlorine in form of hypochlorite ions or chlorine dioxide Extremely active chemcial and acts as potent oxidizing agent, meaning it gives electrons away, Chlorine dioxide is not as potent as hypochlorite as oxidizer in pH ranges found in most wastewaters Chlorine si reactive, and often used up by side reactions before disinfection takes place. Side reactions occur with organic material, hydrogen sulfide, phenols, thiosulfate and ferrious iron. Occur first and make up major use up of chlorine neccesary to reach chlorine demand of wastewater, or amount needed to disinfect it.

Motile

Capable of self propelled movement. A term that is sometimes used ot distinguish between certain types of organisms found in water

Chlorine demand

Demand of inorganic and organic materials taht must react with chlorine first in order to allow for free chlorine to exist in a solution Chlorine remains in combined forms that have disinfecting properties plus free chlorine

Sterilization

Destruction of ALL microorganisms

Disinfection definition

Destruction of all pathogenic microorganisms

Theories of disinfection

Exactly how chlorine kills pathogen is unknown but theories exist Some say chlorine exerts a direct action against bacterial cell killing it, other say toxic character of chlorine inactives enzymes that living microorganisms need to digest food supply, mechanism in wastewater less important than disinfecting properties

Flow from chemical feed pump in GPD formula

Feed pump (gallons per day) = chemical feed (lbs/day) / Chemical solution (lbs/gallon)

Flow delivered by pump formula

Flow (gallons per day)= volume pumped (gallons) X 24 (hours / day) / Time (hours) Or Flow (gallons per minute= volume pumped (gallons) / Time (hours) X 60 (minutes per hour)

Residual chlorine

Free chlorine left over after chlorine demand is met for all organic and inorganic substances that react with chlorine in solution

Uses of wastewater

Irrigating lawns parks cemeteries freeway planting golf courses college campuses athletic fields and other public areas Recreational lakes for boating swimming water skiing fishing and other water sports are made up partially or solely by treated effluent

Coliform

Group of bacteria found in intestines of warm-blooded animals and also in plant soil air and water. The presence of coliform bacteria is an indication that the water is polluted and may contain pathogenic (disease causing) organisms. Fecal coliform are those coliform found in the feces of various warm blooded animals whereas term coliform includes other environmental sources

Organism affected by chlorine depend on

Growth rate and sensitivity and. Concentration of chlorine and exposure time

Hydrogen sulfide reacting with chlorine

Inorganic reducing substance hydrogen sulfide, reacts with chlorine to form sulfuric acid sulfate adn elemental sulfur depending on concentration of hydrogen sulfide pH and temperature One part HS takes about 8.5 parts fo chlorine in reaction 1 and 2.2 parts in reaction 2 desolated in page 350 These reactions occur before chlorine residual occurs, the demand caused by inorganic salts must be satisfied first, before any disinfection can take place, ferrous iron, manganese and nitrite are examples of inorganic reducing agents taht react with chlorine and must be satisified before disinfection can work.

Reaction fo chlorine solution with wastewater

Inorganic reduicng materials- chlorine reacts rapidly with many reducing agents and slowly with others, the exactions complicate use fo chlorine for disinfection.

Bacteria

Living organisms microscopic in size that consist of single cell Most bacteria use organic matter for food and produce waste products as result of thier life process

Chlorine

Most widely used disinfection in US Ultraviolet light is increasing and Ozone is least practiced

Reactions with ammonia

NH3 or ammonia is present in all domestic wastewaters the reaction of ammonia with chlorine is greater significance. when chlorine is added to waters contains ammonia, the ammonia reacts with hypochlorous acid to form monochloromine dichloramine and trichloramine. Thee chloramine formations depend on pH of solution and initial chlorine ammonia ratio. At pH normally found in wastewater 6.5-7.5 monochloramine and dichloramine exist together, and at pH less than 5.5 dichloramine exists by itself and below 4 pH then trichloramine is only compound found

Saprophytes

Nonpathogenic microorganisms that are essential to treatment processes

Sterilization of wastewater

Not practiced because its not practical or necessary too hard to do

Hypochlorite formation

OCI In wastewater 7.3 50 percent of chlorine becomes hypochlorite and the higher the pH level , the greater the amount of OCI produced When used in wastewater, hypochlorite is used in form of sodium hypochlorite Calcium hypochlorite also exists but not used because of its cost, calcium sludge forming characteristics and explosive nature Difference between hypocholorite and chlorine gas is the side reactions formed where sodium hypochlorite plus water creates sodium hydroxide hypochlorious acid hypochlorite acid and hydrogen ions Chlorine gas decreases pH which factors hypochlorous acid formation, while hypochlorite increases pH with formation of hydroxyl ions, at high pH around 10 hypochlorous acid dissociates

Enteric

Of intestinal origin, especially applied to wastes or bacteria.

Chlororganic

Organic compounds combined with chlorine. These compounds generally originate from, or are associated with, life processes such as those of algae in water.

Filamentous organism

Organisms that grow in a thread or filamentous form, common types are thiothrix and actinomycetes a common cause of sludge bulking in the activated sludge process

Orthotolidine

Orthotolidine is a colorimetric indicator of chlorine residual. If chlorine is present, a yellow-colored compound is produced. This reagent is no longer approved for chemical analysis to determine chlorine residual.

Polymer feed formula

Polymer feed (lbs/day) = Polymer concentration (mg/l) X volume pumped (milliliters) X 60 (minutes/hour) X 24(hours/day) / Time pumped (minutes) X 1000 (ml/l) X 1000 (mg/gram) X 454 (gram/pound)

Dechlorination

Removal of chlorine from effluent of plant

Chlorine requirement

The amount of chlorine that is needed for a particular purpose. Some reasons for adding chlorine are reducing the MPN (Most Probable Number) of coliform bacteria, obtaining a particular chlorine residual, or oxidizing some substance in the water. In each case, a definite dosage of chlorine will be necessary. This dosage is the chlorine requirement.

Free residual chlorination

The application of chlorine to water to produce a free available chlorine residual equal to at least 80 percent of the total chlorine residual (sum of free and combined available chlorine residual).

Combined available chlorine residual

The concentration of residual chlorine that is combined with ammonia, organic nitrogen, or both in water as a chloramine (or other chloro derivative) and yet is still available to oxidize organic matter and help kill bacteria.

Degradation

The conversion or breakdown of a substance to simpler compounds for example degradation of organic matter to carbon dioxide ad water

Ambient temperature

The temperature of the surrounding environment.

Dew point

The temperature to which air within a given quantity of water vapor must be cooled to cause condensation of the vapor in the air

Combined available chlorine

The total chlorine, present as chloramine or other derivatives, that is present in a water and is still available for disinfection and for oxidation of organic matter. The combined chlorine compounds are more stable than free chlorine forms, but they are somewhat slower in disinfection action.

Volume pumped formula

Volume pumped (gallons) = area (square feet) X drop (ft) X7.48 (gallons per cubic foot)