OPERATORS CLASS 4

because manganese is only slightly soluble, it is rarely found in surface water above a concentration of... 1mg/L 2mg/L 2.5mg/L 3.0mg/L

1mg/L

which if the usual range of percent sludge solids, if the sludge is allowed to accumulate and compact at the bottom of a sedimentation basin?

2-4%

approximately, which percentage of flow increase occurs when a two-flint screw pump is changed to a three-flight screw pump while all other things being equal

20%

how much time does it usually take to slake lime in the detention time lime slaker?

20-30 mins

to avoid filtration, one criterion is that the fecal coliform concentration must be equal to or less than ____in representative samples of the source water immediately before the first point or only point of disinfectant application in at least ____ of the water measurements made for the previous 6 months that the system served water to the public on an ongoing basis

20/100mL/ 90%

what is typically the percentage of solid material of sum sludge?

0.1-2%

How much acid per 100 mL should be used to preserve a sample for later hardness analyses? a. 0.1mL b. 0.2mL c. 0.5mL d. l.OmL

0.5 ml

How much alkalinity as CaCO3 will dry-basis alum consume?

0.5mg/L

If air is used to generate ozone, which percentage of the air is usually converted to ozone?

1-3%

when water freezes it expands by ___ of its original volume

1/9th

when the external seal water is used as a water source, which should be its pressure be in relation to the volute pressure?

10-15 psi higher

a community water system must post the consumer confidence report on a publicly accessible web site If it serves more than

100,000 people

total dissolved minerals in rainwater are typically close to.. .005mg/L 10mg/L 40mg/L

10mg/L

sites are required to do a site assessment under the process safety management (PSM) regulations (OSHA) if the facility in a single process has more than how many pounds of chlorine?

1500 lbs

at what temperature should the slacking process be maintained?

160 degrees f+

Backwashing rate procedures should be reassessed to determine the cause of granular activated carbon loss if the loss per year exceeds a. 2 inches. b. 4 inches. c. 6 inches. d. 8 inches.

2inches

To help avoid short circuiting, what is the recommended number of flocculation basins in a series?

3 basins

which is the total concentration of dissolved solids in the wastewater from the regeneration of ion exchange units?

35,000-45,000mg/l

water systems are required to achieve at least___ removal and/or inactivation of viruses between a point where raw water is not subject to recontamination by surface water runoff and a point downstream before or at the first customer tap

4 log

At which angle should the parallel inclined plates be installed when using the shallow depth sedimentation method?

45 degrees

approx how much carbon is lost during the reactivation process for granular activated carbon?

5%

at which minimum angle must self cleaning tube settlers be placed?

50 degrees

How thick should the layer of sodium fluoride crystals be maintained

6 inches

each year approximately which percentage of confined space deaths are would be rescuers?

67%

continuous chlorine residual monitoring is required where the water enters the distribution system under the surface water treatment rule when the

> 1000

a single chlorine cylinder is delivering 48 lb/day of chlorine to the water process, causing the cylinder to form a little frost. which would be the best solution to this problem?

add another cylinder and feed from both

which conditions will +eH values of water support?

aerobic conditions

which is the most effective process for the removal of nitrite and nitrate?

anion exchange

particle counters use the principle of light

blockage

sludge produced by water drawn from sources with relatively low turbidity

can be very gelatinous and difficult to handle

Which chemical oxidant would be best to use for controlling trihalomethane formation potential?

chloramines

which would be the most probable solution to control algae in the source water if the algae were clogging the filters at the water plant?

control nurtients

which type of polar bonds are between hydrogen atoms and the oxygen atoms in the water

covalent

conductivity measurements can assist the laboratory analyst in

determining the degree of mineralization of the water

the arrangement of pumps in series is primarily sed to increase the...

discharge head

water that is to be analyzed for inorganic metals should be filtered for___ before___

dissolved metals, preserving

in routine water quality sampling, which one of the following is an early warning sign that conditions are becoming more conducive to sulfate reducing bacteria?

dramatic decline dissolved oxygen

when a water source is destroyed or damaged due to some disaster that causes total contamination, which would be a short term goal?

draw water from a adjoining system or systems

water systems may be allowed by their state to maintain annually, if the state has determined that the system is reliable and consistently below the mcl or organic compounds. when must the water system collect these annual samples?

during the quarter that previously yielded the highest analytical results

where are the sampling points located for required sampling of natural radionuclides in a community water system?

each entry point to the system

Where are the sampling points located for required sampling of organics (except trihalomethane) in a community water system?

entry points to the distribution system

The amount of reject water from reverse osmosis unit is dependent on the number of stages in which the membranes are configured and the

feed pressure

Which sludge dewatering process is best for alum sludges (which are difficult to dewater) when the cakes are very dry, filtrate is clear, and solids capture is very high? a. Centrifuge b. Vacuum filters c. Filter press d. Belt filter press

filter press

In basins using tube and plate settlers, which parameter must be much better than conventional treatment basins?

floc must have good settling characteristics

under which conditions are regenerative turbine pumps used?

high head conditions

Pulsator clarifiers are used to treat water that is?

high in color and low in turbidity

Reverse osmosis membranes will compact faster with...

higher pressure

selfish grown in polluted water have been known to contain the organism that causes

infectious hepatitis

Chlorine is advantageous over chloramines in that chlorine

is a much stronger oxidant

if the activation process of silica is not carefully controlled

it could inhibit coagulation

Which is the primary drawback for facilities that use ultraviolet light to disinfect water?

it does not inactivate microorganisms

water treatment operators must strike a balance between TOC removal and the...

lead and copper rule

public water systems that cannot meet required removal of TOC can comply if the source water TOC lvl is____, calculated quartile as a running annual average

less than 2.0 mg/L

the pressure-reducing and shutoff valve on a vaporizer will shut off when there is a...

loss of electrical power

which method would you use to concentrate and retrieve low numbers of bacteria from large quantity of water?

membrane filtration

water that is to analyzed for inorganic metals should acidified with what acid?

nitric acid bc

if a water system collects at least 40 samples per month for analyses of total coliform, which percent of total coliform positive samples are acceptable for the system to remain in compliance with maximum contaminant level for total coliform?

no more than 5%

What type of polymer is (are) sometimes formulated with regular substance?

nonionic and anionic polymers

Which is the most probable solution if rotifers are visible in the finished water?

optimize coagulation, flocculation, and filtration

If nematodes are interfering with the disinfectant, what is the most probable solution to fix this issue?

optimize the settling process

in regards to safety, wet activated carbon will remove which from the air?

oxygen

Which chemical oxidant would work best on cryptosporidium?

ozone

ammonia gas can be fatal to humans at concentrations as low as

2000ppm

in the presumptive phase of the Most Probable Number test, how long does it take for the coliform to produce gas?

24-48hr

it is impossible to produce waters with a hardness of less than ___ when using the lime soda ash process

25mg/L

A typical coliform colony in the membrane filter method has the following characteristics: a. Blue with lustrous surface sheen b. Pink to dark red with green metallic surface sheen c. Pink or yellow with lustrous to metallic surface sheen depending on species d. Yellow with silver metallic to lustrous surface sheen

pink to dark red with green metallic surface sheen

chemical analysis of for synthetic organic compounds should not be collected in containers made of

polypropylene

The zeta potential on a particular sample of water is -2. The degree of coagulation is best described as...

poor

what is the most advantageous application point for powdered activated carbon?

raw water intake

What is a disadvantage of using a static mixer for coagulation/flocation?

they do not provide good mixing

Magnetic ion exchange resin has been developed to remove?

total organic carbon

which is the most effective method for the removal of disinfection by-products?

ultrafiltrtion= membrane filtration which pressurizes water through semi-permeable membrances

radon is a radioactive decay daughter of

uranium 226

If crustaceans have clogged the water treatment plants filter, what is the most probable solution?

use a disinfectant that targets the specific organism

which algal genera are most likely to case taste and oder problems when abundant in water

volvox

which should be determined first before an in-ground sedimentation tank is drained?

water table level

where does the microbial growth that affects groundwater sources and thus the treatment for removing iron and manganese occur?

where aerobic and anaerobic conditions occur

ozone generates?

will produce about 12% ozone by weight when supplied with air

which factor is used to express volatility of a substance?

Henry's constant = gas law that states amount of dissolved gas in a liquid

which emergency kit is for chlorine tank cars?

Kit C

water treatment personnel should only use self-contained breathing apparatus equipment approved by the

NIOSH (national institute of occupational safety and health)

Natural zeolites used for softening that have become exhausted are regenerated by immersing them in a strong solution of what chemical?

NaCl (sodium chloride)

an employee's average airborne exposure is 8hrs a shift in a 40 hr work week that should not be exceeded is called

Time weighted average (TWA)

Which would immediately occur if newly installed manganese greensand was not skimmed of the fines after backwashing and stratification steps were completed?

shorter filter runs

what is most troublesome operating problem for sedimentation basins?

sludge collection and removal

Which type of sedimentation basins have the flow of water admitted at an angle?

spiral flow basins

What is the best solution if iron bacteria are causing corrosion problems in the filters?

superchlorinate

A conventional water treatment plant with dual media filters has very cold water in the winter and warm water in the summer. what would the operator do to compensate for this temperature change?

sustain the same bed expansion without media loss by reducing flow rates and increasing flow rates

if a substantial chlorine leak incident occurs, which agency should be called for actual hands on assistance>

the Chemical transportation emergency center

The best addition for water that is highly colored due to organic matter

the addition of an acid to lower ph before coagulation