Chapter 14 Q/A (Plant Safety)

Q: What is the role of management in an effective safety training program?

A: Management must be committed to safety and actively support a safety training program. An effective safety training program must start at the top.

Q: List at least four hazards that may be encountered when entering a manhole, excluding atmospheric hazards.

A: Mechanical, electrical, engulfment, and toxic exposure hazards may be encountered when entering a manhole. Physical injury, infections and diseases, and insect and rodent bites are other potential hazards.

Q: According to OSHA regulations, when is a confined space entry permit required?

A: OSHA regulations require that a confined space entry permit be completed for each permit-required confined space entry. The permit must be renewed each time the space is left and re-entered, even if only for a break or lunch, or to go get a tool.

Q: Why do some wastewater treatment plants use bottled water for drinking purposes?

A: Some treatment plants use bottled drinking water because it is an economical and reliable source of potable water. This practice reduces the possibility of the spread of disease from unknown cross connections or defective devices installed to prevent contamination by back flows.

Q: What types of problems can be caused by surface-active agents?

A: Surface-active agents can cause three types of problems: 1. Super floc agents can produce a much denser sludge than usually pumped. This sludge can be pumped. 2. Antifloc agents can lower the capture of suspended solids in primary clarifiers and cause a solids overload on downstream treatment processes. 3. Foaming agents can cause foam to cover treatment processes and prevent inspection and maintenance. Foam that blows into neighbors' yards or forms on the surface of receiving waters is objectionable to the public.

Q: What emergency phone numbers should be listed in a conspicuous place in your plant?

A: The following phone numbers should be conspicuously posted in your plant: fire department, police department, ambulance service, chemical supplier or repair service, and physician. Check your list to be sure they are all listed and the numbers are correct.

Q: List the general categories of hazardous materials.

A: The general categories of hazardous materials include: 1. Corrosives 2. Toxics 3. Flammables and explosives 4. Asphyxiants 5. Harmful physical agents 6. Infectious agents

Q: What information must be on the label of a hazardous material container?

A: The label on a hazardous material container must indicate the name of the hazardous substance and appropriate warnings.

Q: How do toxic and suffocating gases or vapors enter the wastewater treatment plant?

A: The most common toxic gas in wastewater treatment is hydrogen sulfide, which is produced during the anaerobic decomposition of certain materials containing sulfur compounds. Other toxics, such as carbon monoxide, chlorinated solvents, and industrial toxins, may enter your plant as a result of industrial discharges, accidental spills, or illegal disposal of hazardous materials.

Q: What are the necessary ingredients of a fire?

A: The necessary ingredients of a fire are fuel, heat, and oxygen.

Q: Identify the primary elements of the hearing conservation program.

A: The primary elements of the hearing conservation program are monitoring, audiometric testing, hearing protection, training, access to information, and recordkeeping.

Q: What is the purpose of the Material Safety Data Sheet (MSDS)?

A: The purpose of the Material Safety Data Sheet (MSDS) is to have a readily available document to be used for training and as an immediate reference, since it includes information on common names, safe exposure level, the effects of exposure, the symptoms of exposure, whether it is flammable, what type of first aid should be administered, and other information.

Q: What is the purpose of tailgate safety meetings?

A: The purposes of tailgate safety meetings are to remind operators of the need for safety, to explain and discuss safe procedures and safe conditions, and to review potential hazards and how to correct or avoid dangerous situations.

Q; How would you stop the rotating distributor on a trickling filter?

A: The rotating distributor should be stopped by turning off the flow of wastewater. Extreme care must be taken because of the powerful force behind the distributor.

Q: How would you transport tools or equipment into or out of pits or sumps?

A: Tools and equipment should not be carried, but should be transported in and out of pits and sumps by the use of buckets and a handling or sling.

Q: From whom should you receive training regarding the proper use or operation of sewer cleaning tools and equipment?

A: You should receive training regarding the proper use or operation of sewer cleaning tools and equipment from the equipment vendor.

Q: Why should you never work alone on the center Y-wall of an aerator?

A: you should never work alone on the center Y-wall of an aerator and need help getting out.

Q: What is a lockout device and when is it used?

A: A lockout device uses a positive means such as a lock to hold a switch or valve in a safe position and prevent a piece of equipment from becoming energized or moving. Lockout devices are used whenever equipment must be repaired or replaced to ensure that the equipment will not start up or move unexpectedly and possibly injure workers.

Q: What types of moving equipment should you be aware of in a pumping station and what safety precautions should be taken to protect yourself from injury?

A: Be aware of moving equipment in pumping stations, especially reciprocating equipment and rotating shafts. Moving parts that create a contact hazard to employees must be guarded. Do not wear loose clothing, rings, or other jewelry around machinery. Long hair must be secured.

Q: What would you do before relighting a waste gas burner?

A: Before relighting a waste gas burner, the main gas valve should be turned off and the stack allowed to vent itself for a few minutes.

Q: Why are chlorine vents placed at floor level?

A: Chlorine gas is two and a half times heavier than air and is best removed when leaks occurs by blowing the gas out of the room at floor level.

Q: What types of equipment or systems are potentially hazardous for operators due to their stored energy?

A: Examples of equipment or systems that are potentially dangerous for operators due to stored energy include: springs; elevated machine members; rotating flywheels; hydraulic systems; and systems using air, gas, steam, or water pressure.

Q: What type of fire extinguisher should be available in a pumping station?

A: Fire extinguishers in pumping stations should be of a type that may be used on electrical equipment as well as on solid material or power overload-type fires. The use of liquid-type fire extinguishers should be avoided. All-purpose, ABC chemical-type fire extinguishers are recommended.

Q: What safety precautions would you take before entering a recently emptied digester?

A: Follow all confined space procedures before entering AND during occupancy of a recently emptied digester. DO NOT enter unless you are certain that sources of contaminants, such as sludge and gas lines, have been effectively isolated and that safe atmospheric conditions exist and can be maintained before entry and during occupancy.

Q: What parts of equipment should have guards installed around them?

A: Guards should be placed around all moving parts that create a contact hazard to employees.

Q: Why should you always wash your hands before eating?

A: Hands should always be washed before eating to prevent the spread of disease.

Q: List four house keeping tasks that will keep a treatment plant a safer, cleaner place to work.

A: Housekeeping tasks that will keep a treatment plant a safer, cleaner place to work include: 1. Designate a place for tools and equipment and, when they are not being used, keep them in their proper places. 2. Clean up spills of oils, grease, chemicals, polymers, wastewater, and sludge. Keep walkways and work areas clean. 3. Provide proper containers for wastes, oily rags, and papers and empty the containers frequently. 4. Remove snow and ice in areas where a person might slip and fall.

Q: Why is your sense of smell not a reliable method of detecting hydrogen sulfide?

A: Hydrogen sulfide has the unique ability to affect your sense of smell. You will lose the ability to smell hydrogen sulfide's "rotten egg" odor after only a short exposure. Your loss of ability to smell hydrogen sulfide, and certain other odors, is known as olfactory fatigue. NEVER depend on your nose for detection, regardless of he situation.

Q: Why should you never start a positive displacement pump against a closed discharge valve?

A: If a positive displacement pump is started against a closed discharge valve, pressures could build up and break a pipe or damage the pump.

Q: What should you do if you open a door and smell chlorine or sulfur dioxide?

A: If you open a door and smell chlorine or sulfur dioxide, immediately close the door, leave ventilation on, and seek help.

Q: List the major types of discharges from industrial plants that could create safety hazards.

A: Major types of discharges from industrial plants that could create safety hazards include: 1. Fuels 2. Toxic gases 3. Amines 4. Surface-active agents 4. Biocides 5. Highly acidic or alkaline wastes

Q: At what excavation depth does OSHA require a protective system?

A: OSHA requires a protective system when excavations are five feet or more in depth.

Q: How should oil- and paint-soaked rags be handled?

A: Oil- and paint-soaked rags should be placed in covered metal containers and regularly disposed of in a safe manner.

Q: How should one-ton chlorine containers be lifted?

A: One-ton chlorine containers should only be lifted by an approved lifting bar with hooks over the ends of the container.

Q: What types of paperwork are necessary for an effective safety training program?

A: Paperwork necessary for an effective safety training program includes: 1. Accident report forms 2. Safety policy 3. Safety rules 4. Checklists for review of facility plans and specifications and also for plant inspections

Q: What types of respirators must be used in oxygen-deficient atmospheres?

A: Positive-pressure self-contained breathing apparatus (SCBAs) and full-facepiece positive-pressure supplied-air respirators (SARs) with an escape SCBA can be used in oxygen-deficient atmospheres.

Q: Why should safety drills be held regularly?

A: Safety drills should be held regularly so everyone knows how to respond during emergencies. Do not wait for an emergency before trying to learn how to use safety equipment. Get proper instructions and conduct practice sessions.

Q: List three types of safety meetings.

A: Safety meetings could be: 1. Formal, organized meetings 2. Tailgate safety sessions 3. Informal get-togethers

Q: How frequently should safety meetings be held for treatment plant operators?

A: Safety meetings should be held every 7 to 10 working days.

Q: Why should slimes, rags, or greases be removed from around bar screens or racks?

A: Slimes, rags, or grease should be removed from any area because they create slip and trip hazards.

Q: How can the danger of slipping be reduced of slippery surfaces?

A: Slippery surfaces, such as walkways, stairs, ladders, and catwalks, can b made less dangerous by keeping them free of grease, oil, slimes, or other materials and by applying nonslip strips or coatings. To reduce slipping risks, wear safety shoes with nonslip soles and install hand holds and railings.

Q: Why should no smoking or open flames be allowed in the vicinity of digesters?

A: Smoking an open flames should not be allowed in the vicinity of digesters because methane may be present and when methane gas is mixed with the proper proportion of air it forms an explosive mixture.

Q: List the four basic elements of a hazard communication program.

A: The four basic elements of a hazard communication program include: 1. Identify hazardous materials 2. Obtain chemical information and define hazardous conditions. 3. Properly label hazards 4. Train operators

Q: List three ways to warn traffic that you are working in a street or traffic area.

A: Traffic must be warned that you are working in a street or traffic area. BE PREPARED TO STOP, SHOULDER WORK, and UTILITY WORK AHEAD are signs that are effective. Signs with flashing warning lights and vehicles with yellow rotating beacons are used to warn other motorists. Vehicle-mounted traffic guides are also helpful. Use trained flaggers to alert drivers and to direct traffic around the work site. Warning signs and flaggers must be located far enough in advance of the work area to allow motorists time to realize they must slow down, be alert for activity, and safely change lanes or follow a detour.

Q: What do the initials UEL and LEL stand for?

A: UEL stands for the upper explosive limit and LEL stands for the lower explosive limit. UEL and LEL indicate the range of concentrations at which combustible or explosive gases will ignite when an ignition source is present at ambient temperature.

Q: What safety precautions would you take when collecting laboratory samples from a pant influent?

A: When collecting influent samples, disposable, impervious gloves should be worn to protect the operator's hands if there is any chance of direct contact with the wastewater. If possible, sample poles or other similar types of samplers should be used.

Q: When testing the atmosphere before entry in any confined space, what procedure should be used?

A: When testing the atmosphere before entry in any confined space, first test for oxygen deficiency/enrichment, then combustible gases and vapors, and then toxic gases and vapors.

Q: What precautions should you take when using a boat to collect samples from a pond?

A: When using a boat to collect samples from a pond, have someone standing by in case you get into trouble, wear a Coast Guard-approved life jacket, and do not stand up in the boat while performing work.

Q: What precautions would you take when working on electrical or mechanical parts of equipment?

A: When working on mechanical or electrical parts of equipment, you should lock out the main circuit breaker and fasten a tag to the handle or to the lock-out device to notify others that you are working on the equipment and that it must remain de-energized.

Q: How can you help prevent the spread of infectious diseases from your job to you and your family?

A: You can help prevent the spread of infectious diseases from your job to you and your family by immunization shots, thoroughly tasing your hands before eating or smoking, wearing proper protective gloves when you may contact wastewater or sludge in any form, not wearing your work clothes home, keeping your work clothes clean, storing your street clothes and your work clothes in separate lockers, and, if you employer does not supply you with uniforms and laundry service, washing your work clothes separately from your regular family wash.

Q: Why should chemicals and reagents be handled with care?

A; Chemicals and reagents should be handled with care to protect your body from serious injuries and possible poisoning.

Q: What would you do if a gasoline truck was in an accident and the fire department washed the spilled gasoline into a storm drain? The storm drain conveys wastewater to the wet well in the headworks of your treatment plant.

A; If gasoline reaches the wet well in the headworks of your treatment plant: 1. Try to remove the gasoline from the surface of the wet well with skimmers (if available) or with a portable pump. 2. Apply as much ventilation as possible to prevent an explosive atmosphere from developing. 3. Monitor the atmosphere for toxic and explosive conditions. 4. Keep personnel away from the area. 5. Do not allow any flames, sparks, or other sources of ignition in the area (use non sparking tools and explosion-proof equipment and wiring).

Q: List three protective systems for excavations.

A; Three protective systems for excavations are shorting, shielding, and benching and sloping