DNREC monitoring another Lewes wastewater system malfunction

DOVER — Delaware Department of Natural Resources and Environmental Control staff were dispatched Thursday to the Lewes Wastewater Treatment Plant after Tidewater Utilities notified the department that the facility was once again forced to bypass stages of its treatment and discharge partially treated effluent into the Lewes-Rehoboth Canal late Wednesday evening.

The bypass lasted two hours while Tidewater operators worked to find a solution for problems with new treatment membranes. By 11:45 Wednesday night, Tidewater was able to end the bypass and resume normal treatment of effluent at the wastewater treatment plant.

On Thursday, DNREC monitored the WWTP’s operations and Tidewater Utilities’ continued efforts to mitigate recent system malfunctions at the plant.

The Lewes WWTP discharged partially treated effluent from Dec. 18-28, 2019, after a system malfunction caused contamination of the plant’s treatment membranes that filter flow.

New membranes were installed Dec. 28, enabling full treatment to resume at that time, but Tidewater reported Thursday that pressure build-up behind the new membranes required a bypass to avoid compromising their use.

Tidewater, in consult with the membrane manufacturer, has instituted new operational protocols to minimize pressure build-up moving forward, with no further bypass events expected by plant operators. Tidewater also informed DNREC earlier Thursday that an additional set of refurbished membranes were ready to be put back into service later that day to help alleviate strain on the new treatment unit.

DNREC Secretary Shawn M. Garvin confirmed Monday that an environmental violation had occurred when the Lewes WWTP bypassed normal treatment operations between Dec. 18-28 because of the plant’s system malfunction, and that DNREC is currently gathering pertinent information before determining appropriate action.

Department staff will continue to monitor the situation at the plant daily as Tidewater Utilities works toward maintaining consistent treatment of effluent without further system malfunctions.

Although the plant is currently back online and has resumed normal treatment of effluent, DNREC also encourages the public who depend on the Lewes WWTP plant to handle their wastewater to continue practicing water conservation while corrective measures continue at the plant.