Overview

The West Cocalico Township Authority (WCTA) provides wastewater collection and treatment service for portions of West Cocalico and East Cocalico Townships in Lancaster County, PA. With a 50-year-old treatment plant and 65% of on-lot septic systems near or already failing, WCTA needed to take action to protect the ground and surface waters of their community.

We helped WCTA engage the community and permit and design a new 0.31MGD Sequencing Batch Reactor (SBR) wastewater treatment plant (WWTP) and expand the sewer collection system with 3+ miles of new gravity and low-pressure sewer lines and added 149 new connections.

Collection System

Following Act 537 plan actions, private on-lot septic systems in West Cocalico were systematically cleaned and inspected. Those inspections revealed that 65% of those systems were potentially failing or already have failed. The choice was clear, the sewer system needed to be expanded to connect those 149 homes and protect the groundwater from contamination.

The sewer collection system expansion included 8,500 lf. 8-inch gravity sewer, 7,700 lf. 2- to 3-inch low-pressure sewer, 78 grinder pumps, a stream crossing and 2,500 lf. of sewer laterals to connect to the new WWTP. In addition, a 500 lf. section of the existing interceptor was replaced and enlarged to 12-inch pipe to accommodate the additional flow. During preliminary design we also helped WCTA engage and educate homeowners in the sewer expansion area via an educational brochure, FAQ’s, community meetings, and letters.

Wastewater Treatment Plant

After 50 years, WCTA’s existing WWTP had reached the end of its useful life, serving the community well during that time, but it was more cost-effective to build a new plant than completing the necessary upgrades and repairs to the existing plant, which was demolished upon completion of the new plant.

During permitting for the new WWTP, the Pennsylvania Department of Environmental Protection (PADEP) issued surprisingly stringent preliminary effluent levels (PELs) for the new plant, as compared to the existing limits, which also would discharge into the Little Cocalico Creek, a high-quality stream. We were able to successfully work with PADEP to amend the PELs, which saved WCTA over $1,000,000 in additional design, equipment, and construction costs necessary to meet the initial PELs.

The new plant is a 0.31MGD activated sludge wastewater treatment plant, including automatic screen, sequencing batch reactors, ultraviolet disinfection, effluent metering, aerobic digesters, and a control building with full SCADA automation.

This new WWTP was constructed at a new site approximately 1,100 feet south of the existing WWTP, which facilitated the need of 1,700 lf of 8-inch force main between the two sites. The new headworks is located adjacent to the old WWTP and has both the screen and pumps. Taking advantage of the topography at the new WWTP, the forward flow is able to flow by gravity through the treatment process reducing the number of pumps needed, along with their associated costs.

With the plant and collection system in operation, WCTA is already seeing improved treatment and a 30% reduction in sludge and disposal costs. The new collection system and WWTP will efficiently serve WCTA, meet regulatory requirements, and protect the waters of West Cocalico and the Commonwealth for the foreseeable future.