What could an increase in plant effluent coliform levels indicate?

An increase in plant effluent coliform levels primarily indicates issues related to the effectiveness of treatment processes, specifically in the disinfection phase where coliform bacteria are targeted. When coliform levels rise, it often points to the potential for short-circuiting within the contact chamber of the treatment facility, which could mean that water is not receiving the necessary contact time with disinfectants. Inadequate contact time can lead to insufficient reduction of pathogens, resulting in higher coliform levels in the effluent.

In contrast, while poor treatment effectiveness can be related to various factors in the treatment process, the indication of coliform levels specifically points more towards how well the contact chamber is functioning. Overdosing of chlorine typically results in effective disinfection and an overall reduction in coliform levels. Similarly, increased temperature might affect microbial activity but is not a direct indicator of rising coliform levels like short-circuiting is, as this condition directly impacts the process intended for reducing those bacteria in the effluent.