Overview

South Londonderry Township Municipal Authority (SLTMA) was facing regulatory intervention and compliance issues from a failing wastewater treatment lagoon in its system. Rather than re-investing in the unpredictable lagoon, SLTMA chose to replace it with a new wastewater treatment plant (WWTP). We assisted SLTMA with planning, permitting, design and construction management for a new .057MGD plant to control treatment and meet permitted discharge limitations. All of these goals have been achieved.

 

The existing Colebrook lagoon was installed in the 1990s and was one of four small Authority run Wastewater Treatment Plants (WWTPs). The facility had difficulties meeting nitrification requirements in the winter and Total Suspended Solids (TSS) limits in the summer. In response to these performance issues, the Pennsylvania Department of Environmental Protection (PADEP) required a Corrective Action Plan (CAP) and a Consent Order and Agreement (COA) from the Authority.

After reviewing several treatment options the Authority decided to replace the lagoon with a conventional Sequencing Batch Reactor (SBR) plant. The consistency of treatment, flexibility of operating modes, and potential treatment capacity increases were all highly valued by SLTMA and gave them confidence, that it was their best option for the long-term.

We completed design and construction management for the 0.057MGD plant. The facility features influent screening, jet aeration SBRs, UV disinfection, dual tank aerobic digestion and a robust SCADA system.

The SCADA system was one of the larger design requirements from the SLTMA operations staff. It allows for 24-hour daily coverage at the facility. This was the first SCADA based implementation project for SLTMA and begins their long range plan to incorporate all of their plants into a single system. Thus enabling their staff to do more with less resources.

Since the plant has been operational, discharge levels have all been in compliance, and the Authority is greatly positioned to react and comply with any future regulations that may be more stringent. This operational flexibility was an intentional part of the overall design. Furthermore with the planned expandable treatment capacity of the plant, SLTMA can now consider consolidating nearby existing plants as they reach the end of their useful lives.