Inlet works are where raw sewage first enters a wastewater treatment works. The screening area contains mechanical equipment that removes large solids from the flow. Construction workers in these areas face hazards from toxic gases, biological pathogens, moving machinery, and open channels of flowing sewage. This talk covers the specific risks and controls for working safely in inlet works and screening areas.
Key Hazards
Hydrogen sulphide gas accumulating in enclosed inlet structures
Drowning or entrapment in open channels carrying raw sewage flow
Contact with rotating screening equipment causing crushing or amputation
Pathogen exposure from direct contact with raw sewage and screenings
Control Measures
Carry out continuous atmospheric monitoring for H2S and oxygen levels before and during entry.
Ensure all rotating screening equipment is isolated and locked out before any work commences.
Install edge protection around open channels and tanks where there is a risk of falling in.
Wear full waterproof PPE including gloves, overalls, and face protection when near raw sewage.
Ensure hepatitis A vaccination is offered and up to date for all workers on the inlet works.
Cover all cuts and wounds with waterproof dressings before entering the work area.
Use forced ventilation in enclosed inlet structures to disperse accumulated toxic gases.
Wash hands with antibacterial soap before eating, drinking, or smoking after leaving the area.
Brief all operatives on the specific confined space entry requirements for enclosed inlet chambers.
Emergency / Rescue
If a worker collapses near inlet works, suspect H2S poisoning. Do not enter without breathing apparatus. Raise the alarm, call 999, and attempt rescue only with SCBA and a trained rescue team in attendance.
Remember
Hydrogen sulphide is present at inlet works and can kill within minutes at high concentrations
All rotating screening equipment must be isolated and locked out before any work begins
Edge protection is essential around all open channels and tanks carrying raw sewage
Waterproof PPE and wound coverings are mandatory when working near raw sewage
Continuous gas monitoring is required before and during any work in enclosed inlet structures
Applicable Legislation: Confined Spaces Regulations 1997 · COSHH Regulations 2002 · PUWER 1998 · Health and Safety at Work etc. Act 1974