The existing package wastewater treatment facility at the Coachman Estates residential development in Greenville had been demolished and replaced with a pump station in the early 2000s. However, the South Carolina Department of Health and Environmental Control (DHEC) had never “closed” the associated settling lagoon from a regulatory perspective. Renewable Water Resources (ReWa), the local wastewater utility and now owner of the former package treatment facility site, retained Weston & Sampson to close out the lagoon per relevant DHEC regulations and design a replacement pump station with larger pumping capacity and a larger wet well.
Our team worked with ReWa to coordinate sampling of the solids at the bottom of the old lagoon to determine the appropriate closeout and disposal procedures. Once the lagoon’s contents had been characterized, we worked through the DHEC closeout procedure and submitted the required paperwork to the state.
ReWa expressed their preference for using grinder pumps at the new pump station. The existing small-diameter force main was several miles long and passed through hilly terrain, resulting in significant elevation changes over the course of its run. After calculating the hydraulics for this unique pump and force main system, we worked with equipment suppliers to select the appropriately sized pumps to meet the requirements of the system. Our innovative design allows the existing pump station to remain online while the new one is constructed, tested, and accepted by ReWa. This design lessens the need for bypass pumping, reducing costs and complexity during the construction phase. Our design also included a precast polymer concrete wet well, which will reduce costs associated with annual maintenance needs, compared to those associated with a traditional concrete wet well.
We are awaiting final determination from DHEC on the closeout of the lagoon, but expect to receive that shortly. We recently delivered final 100% design documents for the new pump station and will provide ReWa with construction administration services during pump station construction.
Key Projects Features:
- regulatory closure of a wastewater lagoon
- force main hydraulics
- 30%, 60%, and 100% wastewater pump station design
- contract administration