Recently, we were engaged to assist a new client with the evaluation of their existing wastewater pretreatment system. There were three reasons for this project. First, the wastewater effluent was consistently out of compliance with zinc. Secondly, the city had issued a number of notices of violations (NOVs) and was demanding quick action to resolve the situation. Lastly, the client desired to significantly upgrade their existing system to handle more flow due to increasing business as well as to achieve consistent compliance. One of the first actions we performed was to thoroughly review their wastewater discharge permit. We identified two issues. First, the city appeared to have overestimated the amount of “dilute” wastewater that flows through the sampling location, thus lowering the facility’s categorical limits more than it should be. We are collecting the data needed to convince the city that these “dilute” wastewater flows are much lower than estimated. Also, at the same time, we are evaluating the feasibility of discharging these “dilute” wastewaters through another plant sewer so that they do not mix with the categorical process wastewaters before the public sewer.
Most importantly, we found that the city made a math error in calculating the facility’s zinc limit, thereby, reducing the limit by 10 times! After bringing this error to the city’s attention, they quickly revised the permit with the higher limit; this correction dramatically reduced the number and severity of violations.
whether you receive a new or renewed permit, take the time to thoroughly review it to be sure it is accurate, and you understand ALL of its provisions, otherwise, it can prove to be very costly, both in terms of your time and money.