Wastewater treatment works contain numerous open tanks, channels, and process areas that present drowning hazards to construction workers. Many tanks contain aerated liquids that cannot support a person's weight, and others contain deep sludge that can trap and engulf a fallen worker. This talk covers the drowning prevention controls specific to working around open water on wastewater treatment sites.
Key Hazards
Drowning in aerated process tanks where the liquid cannot support body weight
Engulfment in deep sludge deposits in settlement tanks and lagoons
Falls from unprotected tank edges and walkways into open process water
Cold water shock reducing the ability to self-rescue after falling in
Control Measures
Install edge protection around all open tanks, channels, and process areas before construction begins.
Wear an auto-inflating personal flotation device within two metres of any open water on the works.
Position lifebuoys and throw lines at regular intervals around open process tanks and channels.
Ensure a buddy system is in place so no one works alone near open water at any time.
Brief all operatives on the man overboard procedure and the location of all rescue equipment.
Cover or fence any tank opening that is not protected by permanent edge protection.
Ensure a rescue plan specific to each tank type and location is in place before work begins.
Monitor tank liquid levels and notify operatives if levels change during the working shift.
Ensure adequate lighting around tank edges and walkways for work during darkness or poor visibility.
Emergency / Rescue
If someone falls into a process tank, throw a lifebuoy immediately and shout for help. Do not enter the tank — aerated water cannot support you. Call 999 and raise the site alarm. Shut down aeration if safe to do so.
Remember
Edge protection must be in place around all open tanks and channels before work begins
Wear an auto-inflating PFD within two metres of any open water on the treatment works
Lifebuoys and throw lines must be positioned at regular intervals around all open tanks
A buddy system must be in place so no person works alone near open water at any time
A rescue plan specific to each tank type and location must be prepared before work starts
Applicable Legislation: CDM Regulations 2015 · Management of Health and Safety at Work Regulations 1999 · Work at Height Regulations 2005 · Health and Safety at Work etc. Act 1974