Egg-Shaped Digester, Clearwater Road Wastewater Treatment Facility, Derry Township Municipal Authority, Hershey, PA

BH provided design and construction management for various improvements to Derry Township Municipal Authority’s Clearwater Road Wastewater Treatment Facility.

These improvements include a new egg-shaped anaerobic sludge digester; conversion of an existing sludge storage tank to a secondary digester; addition of a digester control building to house a boiler, and digester gas handling equipment; construction of a covered biosolids storage pad; addition of a new headworks structure; replacement of sludge transfer and belt press feed pumps; addition of mixing equipment to existing scum pits; and rehabilitation of the plant’s raw sewage pumping system.

The new headworks structure has an average design flow capacity of 6.3 MGD and a peak hydraulic flow capacity of 18.0 MGD. It includes two mechanical cylindrical influent screens to remove and dewater rags, plastics, etc. from the influent flow stream, shaftless screw conveyors to transport screenings to a storage container, and two vortex type grit removal units from which grit is pumped to a grit dewatering screw conveyor and then discharged to a storage container.

Two truck receiving pads have been provided for the off-loading of trucked-in septage and liquid sludges. A lime storage silo and lime slurry system are provided to feed lime to the trucked-in wastes as they are being discharged to minimize odors, raise their pH, and enhance removal in the treatment plant’s primary clarifiers.

During the construction phase, BH provided full-time project representation and construction management. Duties included technical support, problem resolution, submittal review and approval, contractor schedule review job conferences, budget monitoring, photo documentation, quality assurance, change order negotiation and processing, application for payment review, client liaison, substantial and final completion inspection, start-up assistance, and warranty period support and close-out.