Poor effluent quality
Hamworthy Super Trident ST6A, biological (aerobic) sewage treatment plant, imo mepc.2(vi)
Possible cause
Lack of oxygen, killed bacteria by disinfectant cleaners, sludge not returning, too much flushing water
What to do
Manufacturer's manual, p. 56Check compressors, filters and valves; stop disinfectant cleaners; set air-lifts; fix leaking flush valves
See the assembly on the 3D model
Other Hamworthy Super Trident ST6A faults
Tank overflow / high level alarmDischarge pump failure, pipe blockage or excessive inflow (leaking WC flush valves)Bad smell from the unitAnaerobic tank: compressor, air-lifts or diffusers not working, or too much sludgeScum on the settling tankSkimmer or air-lifts not workingFoaming in the aeration tank and ventToo much cleaning agentDischarge pump gives no flowClosed valves, blocked suction, air leaks or loops in suction pipeReduced or irregular pump dischargeChoked impeller, valve or non-return valve partly closedAir gauge 0.2 bar above normal / relief valve blowingClogged diffuser elements or dirty filters
From the manufacturer's manual “Sewage treatment plant manual”. Check against the original on board before work.