WWT/Process Areas/TBT-WWT-006

Inlet Works and Screening Safety

Water & Wastewater Treatment › Process Areas › Inlet Works and Screening Safety

Presenter		Project
Location		Date

Inlet works is the first stage of wastewater treatment where raw sewage enters the site through screens that remove large solids.
Screenings include rags, wipes, plastics, sanitary products, and grit — all contaminated with raw sewage and biological hazards.
Mechanical screens with moving rakes, augers, and conveyors create entanglement and trapping hazards around the equipment.
Hydrogen sulphide gas is frequently present at inlet works due to the decomposition of organic material in the incoming flow.
Channels, chambers, and below-ground structures at inlet works may be classified as confined spaces requiring entry permits.
Biological hazards from raw sewage include leptospirosis, hepatitis, E.coli, and other pathogens causing serious illness.
Manual handling of screenings skips and cleaning of blocked screens exposes workers to contaminated material at close range.
LOTO procedures must be followed before any maintenance work on mechanical screening equipment, rakes, or conveyors.
Personal hygiene is critical — hands must be washed with antibacterial soap before eating, drinking, or smoking.
Drowning risk exists in deep channels and chambers where workers can fall into fast-flowing incoming sewage.

H2S exposure	Hydrogen sulphide accumulates at inlet works where raw sewage first enters — gas levels can reach lethal concentrations rapidly.
Biological infection	Raw sewage contains pathogens that cause leptospirosis, hepatitis, and gastroenteritis — strict hygiene prevents infection.
Entanglement	Mechanical screen rakes and conveyors trap, entangle, and crush — LOTO isolation must be confirmed before any maintenance.

Don't

Wear a personal gas monitor for H2S detection at all times at inlet works.
Treat below-ground channels and chambers as confined spaces requiring entry permits.
Follow LOTO procedures before maintaining screens, rakes, conveyors, or augers.
Wear waterproof PPE, gloves, and face protection when handling screenings.
Wash hands with antibacterial soap before eating, drinking, or smoking.
Cover all cuts and wounds with waterproof dressings before starting work.
Maintain fall protection at deep channels to prevent falling into incoming sewage.
Keep up to date with hepatitis and tetanus vaccinations for sewage-exposed workers.
Report any illness symptoms including nausea, fever, or skin infection promptly.
Brief all workers on biological hazards and hygiene procedures at inlet works.

DON'T work at inlet works without a personal H2S gas monitor running at all times.
DON'T enter below-ground structures without a confined space permit and gas testing.
DON'T approach moving screen rakes or conveyors without confirming LOTO isolation.
DON'T handle screenings without waterproof gloves, PPE, and face protection.
DON'T eat, drink, or smoke without thorough hand washing with antibacterial soap.
DON'T work with open cuts near raw sewage — cover them with waterproof dressings.
DON'T work near deep channels without fall protection preventing entry into the flow.
DON'T skip vaccination boosters required for sewage-exposed workers.
DON'T ignore early signs of illness after working at inlet works — report them.
DON'T assume inlet works are safe because you visit regularly — hazards are always present.

See also: Wastewater Treatment Works Safety Awareness | Hydrogen Sulphide (H2S) on WwTW

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