Chlorine gas disinfection, if ...

Chlorine gas disinfection, if correctly controlled, is highly effective. One would need a good idea of the treated effluent quality before one could venture a response, for example effluent COD, suspended solids, ammonia and pH. Furthermore one would need to confirm where and how the gas (solution) is dosed (adequate mixing upstream of the chlorine contact tank, etc), the size of the chlorine contact tank, the condition of the chlorine contact tank (is settled sludge regularly cleaned out) and where the sample is taken for the residual chlorine test.