The resulting high quality final clarifier effluent is disinfected using ultraviolet light and discharged to the Swatara Creek.

A portion of the removed activated sludge is returned to the head of the biological process and a portion is wasted. This mixed liquor then flows into the final clarifiers where the biological (or activated) sludge is settled and removed.

During the biological step, ferric chloride is added to what is now known as mixed liquor to remove phosphorous. The WWTF uses a three-phase biological treatment process that includes primary anoxic, oxic, and secondary anoxic followed by reaeration to remove pollutants including total nitrogen to very low levels. Wastewater then flows to the biological treatment processes. The WWTF is one of the few facilities accepting trucked grease trap waste for disposal.įollowing preliminary screening and grit removal, all settleable materials are removed as a primary sludge in the subsequent primary clarification step. Immediately adjacent to the headworks is a two-lane septage receiving station and grease trap pretreatment facility. Screenings and grit removed in the headworks are discharged to a dumpster for disposal at a landfill. The headworks equipment includes two self-cleaning cylindrical screens with dewatering and conveyance conveyors, metering equipment, and two induced vortex grit removal units. Influent wastewater is pumped from the wet well to the headworks using dry pit centrifugal pumps controlled by redundant level transmitters and operated by state of the art variable frequency drives.

It is designed to treat 5.02 MGD of wastewater to a level meeting or exceeding all current PA DEP, EPA, and Chesapeake Bay requirements. The WWTF, which was originally constructed in 1976, has had numerous improvements constructed over the past few years.

The service area includes more than 8,000 customers including two significant industrial users. The DTMA Clearwater Road (CWR) Wastewater Treatment Facility (WWTF) provides complete treatment of the wastewater generated in the Township of Derry and surrounding communities. Since the mid-1990s, BH has worked with the Authority in completing long-term facilities planning, design, and construction management for the entire collection, conveyance, and treatment system.

Derry township pennsylvania