Wastewater Treatment Plant Safety Manual

Wastewater Treatment Plant Safety Programs

The programs needed at a wastewater treatment facility depend on the processes, equipment, chemicals, and employee activities present. A comprehensive manual may include programs covering:

• Wastewater Treatment Safety
• Confined Space Entry
• Hydrogen Sulfide Safety
• Chlorine Safety
• Chemical Safety
• Hazard Communication
• Respiratory Protection
• Personal Protective Equipment
• Bloodborne Pathogens
• Biological Hazards
• Lockout/Tagout
• Electrical Safety
• Machine Guarding
• Fall Protection
• Walking-Working Surfaces
• Laboratory Safety
• Hearing Conservation
• Emergency Action Plan
• Spill Prevention and Response
• Job Safety Analysis
• First Aid

Programs that do not apply to the facility’s operations can be removed, while additional programs should be included when specialized processes create additional hazards.

Wastewater Treatment Hazards

Wastewater treatment plants contain a combination of chemical, biological, mechanical, electrical, atmospheric, and physical hazards.

Potential hazards may include:

• Hydrogen sulfide
• Oxygen-deficient atmospheres
• Chlorine and treatment chemicals
• Sewage and biological contaminants
• Confined spaces
• Open tanks and basins
• Pumps and rotating machinery
• Electrical systems
• Pressurized equipment
• Slippery walking surfaces
• Hazardous energy
• Noise
• Vehicle and mobile equipment
• Laboratory chemicals
• Heat and cold exposure

Hazards should be evaluated by treatment process and employee task rather than assuming all areas of the facility present the same exposures.

Hydrogen Sulfide Safety

Hydrogen sulfide can be produced by the decomposition of organic material and may accumulate in wastewater systems, wet wells, sewers, tanks, pits, manholes, sludge-processing areas, and other poorly ventilated locations.

Hydrogen sulfide is highly toxic and can rapidly create a life-threatening atmosphere.

Employees should understand that odor is not a reliable means of detecting dangerous hydrogen sulfide concentrations.

Where hydrogen sulfide may be present, appropriate controls may include:

• Atmospheric monitoring
• Fixed gas-detection systems
• Portable gas monitors
• Ventilation
• Restricted access
• Respiratory protection
• Confined-space procedures
• Emergency response procedures

Employees should not enter an area suspected of containing a dangerous atmosphere without appropriate evaluation and protective measures.

Atmospheric Monitoring

Wastewater facilities may require atmospheric monitoring in areas where hazardous gases or oxygen-deficient conditions can develop.

Monitoring may include:

• Oxygen
• Hydrogen sulfide
• Combustible gases and vapors
• Chlorine
• Other process-specific contaminants

Monitoring equipment should be appropriate for the anticipated hazards, maintained according to manufacturer instructions, and calibrated or function-tested as required.

Employees using portable gas monitors should understand alarm settings, limitations, proper use, and required actions when an alarm activates.

Gas-monitor alarms should never be ignored or disabled to permit work to continue.

Confined Space Entry

Wastewater operations contain numerous locations that may qualify as confined spaces or permit-required confined spaces.

Potential spaces include:

• Manholes
• Wet wells
• Lift stations
• Tanks
• Digesters
• Pits
• Vaults
• Sewers
• Process vessels
• Underground chambers

Confined spaces should be identified and evaluated before employees enter them.

When permit-required confined-space entry is necessary, procedures should address:

• Entry permits
• Atmospheric testing
• Ventilation
• Isolation
• Lockout/tagout
• Entrant responsibilities
• Attendant responsibilities
• Entry supervision
• Communication
• Rescue
• Personal protective equipment

Unauthorized employees should be prevented from entering permit-required confined spaces.

Confined Space Atmospheric Hazards

Confined spaces in wastewater operations may contain or develop:

• Oxygen deficiency
• Hydrogen sulfide
• Methane
• Flammable atmospheres
• Toxic chemicals
• Process gases

Atmospheric testing should be performed in the appropriate sequence and continued as necessary to ensure acceptable entry conditions.

Ventilation should not be considered a substitute for atmospheric testing.

Employees should immediately leave the space when required conditions are no longer maintained.

Confined Space Rescue

Wastewater facilities should establish appropriate rescue provisions before permit-required confined-space entry begins.

Rescue planning should consider:

• Space configuration
• Access
• Atmospheric hazards
• Retrieval equipment
• Employee positioning
• Communication
• Response time
• Required PPE
• Respiratory protection

Employees should never make an unplanned entry into a hazardous confined space to attempt a rescue.

When non-entry retrieval is feasible and appropriate, required retrieval systems should be available and properly used.

Chlorine Safety

Wastewater treatment facilities that use chlorine gas or chlorine-containing products should establish procedures appropriate to the chemicals and systems present.

Potential chlorine exposure can result from:

• Leaking cylinders or containers
• Damaged piping
• Valve failures
• Improper connections
• Chemical transfer
• Equipment maintenance
• Accidental releases

Employees should be trained to recognize chlorine hazards and understand alarms, emergency procedures, evacuation requirements, and respiratory hazards.

Only appropriately trained and equipped personnel should respond to hazardous chlorine releases.

Treatment Chemical Safety

Wastewater facilities may use chemicals such as:

• Sodium hypochlorite
• Chlorine
• Ferric chloride
• Alum
• Polymers
• Acids
• Caustics
• Disinfectants
• Laboratory reagents
• Cleaning chemicals

Chemical hazards should be evaluated before use.

Employees should follow applicable procedures for:

• Receiving
• Transfer
• Storage
• Mixing
• Dilution
• PPE
• Spill response
• Disposal

Incompatible chemicals should be segregated as necessary to prevent dangerous reactions.

Chemical Transfer and Unloading

Bulk chemical deliveries may expose employees to corrosive materials, vehicle movement, hose failures, spills, and incompatible chemical transfer.

Before unloading begins:

• Verify the chemical.
• Verify the receiving tank.
• Inspect connections and hoses.
• Confirm available capacity.
• Establish communication with the driver.
• Wear required PPE.
• Verify emergency equipment.
• Control vehicle movement.

Connections should be clearly identified to reduce the possibility of transferring chemicals into the wrong tank.

Hazard Communication

Employees should have access to information about hazardous chemicals used or stored at the facility.

The Hazard Communication Program should address:

• Chemical inventory
• Container labeling
• Safety Data Sheets
• Employee training
• Non-routine tasks
• Chemical storage
• Protective measures

Employees should know where Safety Data Sheets are maintained and how to obtain information about chemical hazards.

Personal Protective Equipment

PPE should be selected based on a hazard assessment and the work being performed.

Wastewater PPE may include:

• Safety glasses
• Goggles
• Face shields
• Chemical-resistant gloves
• Work gloves
• Chemical-resistant clothing
• Protective footwear
• Hard hats
• Hearing protection
• High-visibility apparel
• Respiratory protection
• Fall protection equipment

PPE should be inspected before use, maintained appropriately, and replaced when damaged or contaminated beyond safe use.

Respiratory Protection

Respiratory protection may be required for certain wastewater operations involving toxic gases, chemical exposures, emergency response, or other respiratory hazards.

When respirators are required, the facility should maintain a Respiratory Protection Program addressing:

• Respirator selection
• Medical evaluations
• Fit testing
• Training
• Inspection
• Cleaning
• Storage
• Filter or cartridge replacement
• Program evaluation

Atmospheres that are immediately dangerous to life or health require specialized respiratory protection and procedures.

Employees should never enter an unknown or potentially IDLH atmosphere using inadequate respiratory protection.

Biological Hazards

Wastewater and sewage can contain bacteria, viruses, parasites, and other biological contaminants.

Employees may be exposed through:

• Skin contact
• Cuts or abrasions
• Splashes
• Aerosols
• Contaminated tools
• Contaminated surfaces
• Hand-to-mouth contact

Employees should minimize direct contact with wastewater and use appropriate PPE.

Good hygiene is an important part of wastewater-worker protection.

Personal Hygiene and Decontamination

Employees working with sewage or contaminated equipment should:

• Wash hands before eating, drinking, smoking, or leaving work.
• Avoid touching the face with contaminated gloves.
• Cover cuts and abrasions.
• Remove contaminated PPE appropriately.
• Clean reusable equipment.
• Keep food and beverages away from contaminated work areas.
• Change contaminated clothing when necessary.

Facilities should provide appropriate washing and decontamination provisions based on employee exposures.

Bloodborne Pathogens

Wastewater itself is not automatically treated as an occupational bloodborne-pathogen exposure, but employees may encounter blood or other potentially infectious materials during first aid, sharps incidents, or other activities.

The facility should evaluate employee duties to determine whether occupational exposure to bloodborne pathogens exists.

Employees should use appropriate precautions when blood or other potentially infectious materials are encountered.

Sharps and Needles

Needles, syringes, broken glass, and other sharp objects may enter wastewater collection and treatment systems.

Employees should never pick up unidentified sharps with bare hands.

Appropriate tools, puncture-resistant containers, gloves, and procedures should be used for handling and disposal.

Employees should report needlestick and sharps injuries immediately.

Open Tanks, Basins and Water Hazards

Clarifiers, aeration basins, channels, digesters, tanks, and other open process areas can create fall and drowning hazards.

Protection may include:

• Guardrails
• Gates
• Covers
• Personal fall protection
• Safe walkways
• Rescue equipment
• Restricted access
• Adequate lighting

Employees should not climb over or bypass guardrails.

Work performed where employees could fall into water or wastewater should be evaluated for appropriate fall and water-rescue precautions.

Walking-Working Surfaces

Wastewater facilities frequently contain wet, slippery, uneven, or chemically contaminated walking surfaces.

Employees should:

• Clean spills promptly.
• Report leaks.
• Keep walkways clear.
• Maintain drainage.
• Use handrails.
• Wear appropriate footwear.
• Use caution around algae, ice, grease, sludge, and standing water.

Damaged grating, stairs, platforms, or handrails should be reported and repaired.

Fall Protection

Employees may be exposed to falls while working around:

• Tanks
• Basins
• Clarifiers
• Elevated platforms
• Roofs
• Ladders
• Openings
• Pits
• Equipment

Fall hazards should be evaluated and appropriate protection provided.

Protection may include guardrails, covers, personal fall protection systems, and other appropriate measures.

Lockout/Tagout

Wastewater facilities contain pumps, mixers, conveyors, screens, compactors, centrifuges, blowers, valves, and other equipment capable of releasing hazardous energy.

Employees performing servicing or maintenance should follow established energy-control procedures.

Hazardous energy may include:

• Electrical
• Mechanical
• Hydraulic
• Pneumatic
• Chemical
• Thermal
• Pressure
• Gravity

Equipment should be isolated, locked or tagged as required, and verified before servicing begins.

Pumps and Rotating Equipment

Pumps, motors, shafts, couplings, blowers, mixers, and other rotating equipment can create caught-in and entanglement hazards.

Employees should:

• Keep guards in place.
• Avoid loose clothing and jewelry.
• Keep hands away from moving components.
• Follow lockout/tagout procedures before servicing.
• Report unusual vibration, noise, or leaks.

Damaged or missing guards should be corrected before equipment is operated.

Machine Guarding

Screens, conveyors, belt presses, centrifuges, compactors, grinders, and other wastewater equipment may contain hazardous moving parts.

Machine guarding should protect employees from:

• Points of operation
• Rotating parts
• Nip points
• Belts and pulleys
• Gears
• Shafts
• Other moving components

Employees should not remove or bypass guards except as part of authorized servicing procedures with appropriate energy controls.

Electrical Safety

Wastewater facilities combine electrical equipment with water and wet environments.

Employees should be particularly alert to damaged electrical equipment, moisture intrusion, temporary wiring, and unsafe work practices.

Only qualified employees should perform electrical work requiring specialized knowledge.

Electrical equipment should be maintained and protected for the environment in which it is used.

Arc Flash and Electrical Maintenance

Qualified employees performing electrical maintenance may be exposed to shock, arc-flash, and arc-blast hazards.

Electrical safety procedures should address:

• Hazard assessment
• De-energization
• Lockout/tagout
• Approach boundaries
• Appropriate PPE
• Energized work
• Test instruments
• Employee qualifications

Electrical equipment should normally be placed in an electrically safe condition before work when required.

Laboratory Safety

Wastewater treatment laboratories may perform sampling and analysis involving chemicals, reagents, glassware, heating equipment, and biological materials.

Laboratory safety procedures may address:

• Chemical handling
• PPE
• Labeling
• Safety Data Sheets
• Sample handling
• Glassware
• Chemical storage
• Spill response
• Waste disposal
• Emergency equipment

Laboratory personnel should receive training appropriate to the analyses and chemicals they use.

Wastewater Sampling

Employees collecting wastewater samples may be exposed to biological contaminants, chemicals, slippery surfaces, traffic, open tanks, and remote work locations.

Employees should:

• Wear appropriate PPE.
• Use safe sampling methods.
• Avoid unnecessary direct contact.
• Maintain stable footing.
• Use caution around open water.
• Follow hygiene procedures.
• Use appropriate sample containers.

Sampling from manholes or confined spaces should be performed without entry whenever practical.

Sludge Handling

Sludge-processing operations may expose employees to biological contaminants, gases, machinery, chemicals, and slippery surfaces.

Operations may involve:

• Belt presses
• Centrifuges
• Digesters
• Pumps
• Conveyors
• Drying systems
• Dewatering equipment

Employees should follow appropriate PPE, machine guarding, lockout/tagout, hygiene, and atmospheric-hazard procedures.

Digesters

Digesters can present serious hazards involving methane, hydrogen sulfide, oxygen deficiency, fire, explosion, confined spaces, and pressure.

Access should be controlled.

Ignition sources should be managed appropriately.

Atmospheric conditions should be evaluated before work in potentially hazardous locations.

Maintenance activities should be carefully planned and coordinated.

Lift Station Safety

Lift stations may contain confined spaces, hazardous atmospheres, electrical equipment, pumps, traffic exposures, and biological hazards.

Before maintenance or entry:

• Evaluate atmospheric hazards.
• Control hazardous energy.
• Establish traffic protection when required.
• Use appropriate PPE.
• Establish confined-space procedures when applicable.
• Maintain communication.

Employees should avoid entering wet wells whenever the task can safely be performed without entry.

Sewer and Collection System Safety

Employees working in wastewater collection systems may encounter:

• Traffic
• Confined spaces
• Hydrogen sulfide
• Methane
• Biological hazards
• Flow hazards
• Heavy covers
• Mobile equipment
• Underground utilities

Work should be planned before opening manholes or entering collection-system structures.

Appropriate traffic control should be established when employees work in or near roadways.

Manhole Safety

Manholes should be approached as potential confined-space and traffic hazards.

Before opening a manhole:

• Establish traffic control when required.
• Evaluate the location.
• Use appropriate lifting tools.
• Control pedestrian access.
• Evaluate atmospheric hazards.
• Prevent unauthorized entry.

Employees should not place their head or upper body into a manhole to evaluate conditions.

Atmospheric monitoring equipment should be used when required.

Traffic Control

Wastewater employees may perform work in streets, roadways, parking areas, and other locations exposed to vehicles.

Traffic-control measures may include:

• Signs
• Cones
• Barricades
• Channelizing devices
• Flaggers
• High-visibility apparel
• Vehicle positioning

Work zones should be established before employees enter exposed roadway areas.

Chemical Spill Response

Facilities should maintain procedures for spills involving treatment chemicals, fuels, oils, laboratory chemicals, and other hazardous substances.

Employees should know:

• How to report a spill.
• When to evacuate.
• Which PPE is required.
• Where spill-control materials are located.
• Which employees are authorized to respond.
• How incompatible chemicals should be managed.

Employees should not attempt to control spills beyond their training and available protective equipment.

Emergency Response

Wastewater facilities should plan for foreseeable emergencies, which may include:

• Hydrogen sulfide releases
• Chlorine releases
• Chemical spills
• Confined-space emergencies
• Fires
• Explosions
• Electrical incidents
• Falls into tanks or basins
• Equipment incidents
• Severe weather
• Medical emergencies

Employees should understand alarm systems, evacuation procedures, emergency communication, and assembly locations.

Fire and Explosion Prevention

Wastewater processes may generate methane or other flammable gases.

Fire-prevention procedures should address:

• Ignition sources
• Hot work
• Flammable materials
• Electrical equipment
• Gas detection
• Chemical storage
• Emergency shutdown
• Fire extinguishers

Hot work in or near process equipment, tanks, digesters, or collection systems should receive appropriate evaluation and authorization.

Hot Work

Welding, cutting, grinding, and other hot work may be required during wastewater maintenance.

Before hot work begins:

• Evaluate combustible materials.
• Evaluate atmospheric hazards.
• Obtain required permits.
• Provide fire protection.
• Control hazardous energy.
• Provide ventilation when necessary.
• Establish fire watch requirements when applicable.

Hot work should not begin in potentially flammable atmospheres until appropriate precautions have been established.

Mobile Equipment and Vehicles

Wastewater facilities may use:

• Utility vehicles
• Forklifts
• Loaders
• Excavators
• Vacuum trucks
• Sludge trucks
• Tractors
• Maintenance vehicles

Only trained and authorized employees should operate equipment requiring operator training.

Operators should inspect equipment, wear seat belts when provided, maintain safe speeds, and remain alert to pedestrians.

Manual Lifting and Material Handling

Employees may handle pumps, hoses, manhole covers, chemical containers, tools, equipment parts, and other heavy or awkward materials.

Employees should evaluate loads before lifting and use:

• Mechanical lifting equipment
• Carts
• Hoists
• Dollies
• Team lifting

Manual handling should be minimized when mechanical assistance is practical.

Hearing Conservation

Blowers, pumps, generators, centrifuges, compressors, and other equipment may create hazardous noise.

The facility should evaluate employee noise exposures and implement a Hearing Conservation Program when required.

Hearing protection should be selected, used, and maintained appropriately.

Heat and Cold Stress

Wastewater employees may work outdoors year-round and may also work in hot mechanical areas or cold process locations.

Heat illness prevention may address:

• Drinking water
• Rest
• Shade
• Acclimatization
• Work scheduling
• Recognition of heat illness

Cold-weather procedures may address:

• Appropriate clothing
• Wet conditions
• Ice
• Warming opportunities
• Reduced dexterity
• Recognition of cold-related illness

Job Safety Analysis

A Job Safety Analysis (JSA) can help wastewater facilities identify hazards before higher-risk or non-routine work begins.

JSAs may be appropriate for:

• Confined-space entry
• Manhole entry
• Lift-station maintenance
• Pump maintenance
• Chemical unloading
• Chlorine-system maintenance
• Wastewater sampling
• Sludge handling
• Tank cleaning
• Electrical maintenance
• Hot work
• Lockout/tagout
• Work around open basins
• Sewer maintenance

The JSA should identify the steps of the task, associated hazards, and controls needed to perform the work safely.

Wastewater Treatment Safety Training

Employees should receive training appropriate to their assigned work and exposures.

Training may include:

• Wastewater hazards
• Hydrogen sulfide
• Confined spaces
• Atmospheric monitoring
• Chemical safety
• Chlorine safety
• Hazard communication
• PPE
• Respiratory protection
• Biological hazards
• Lockout/tagout
• Machine guarding
• Electrical safety
• Fall protection
• Traffic control
• Emergency procedures

Training should be documented and updated when processes, chemicals, equipment, employee responsibilities, or regulatory requirements change.

Building a Wastewater Treatment Plant Safety Manual

A Wastewater Treatment Plant Safety Manual should be customized to the facility’s actual processes rather than relying solely on a generic industrial or utility safety manual.

A small municipal wastewater facility may require a different combination of programs than a large regional treatment plant with anaerobic digesters, chlorine systems, laboratories, sludge dewatering, collection-system crews, multiple lift stations, and extensive maintenance operations.

Industrial wastewater facilities may have additional chemical, process, and customer-specific hazards that should also be incorporated into the manual.

The manual should reflect the facility’s treatment processes, chemicals, confined spaces, atmospheric hazards, equipment, laboratories, collection systems, maintenance activities, and emergency-response capabilities.

The completed safety manual should provide practical procedures employees and supervisors can use while supporting OSHA compliance, employee training, hazard assessments, JSAs, inspections, incident investigations, emergency planning, and the facility’s overall safety-management system.