Engineering - Wastewater

The Greenwood Metropolitan District upgraded the Wilson Creek Wastewater Treatment Plant. As part of the work, Metro also upgraded a portion of the existing 30-inch Wilson Creek and 36-inch Coronaca Creek trunk sewers for this plant. Design South was retained as the consultant for the improvements to the trunk sewer.

The design included installation of approximately 3,400 feet of sewer utilizing 72-inch HDPE pipe. Junction structures were constructed near the confluence of the existing sewers to capture the wastewater flow from the existing 30-inch Wilson Creek and 36-inch Coronaca Creek influent lines. Provisions are included in the junction structures for future 60-inch expansion along the Coronaca Creek sewer and 48-inch expansion along the Wilson Creek sewer. Manholes for the project were also fabricated from HDPE material.

The design for this project featured installation of the pipeline in challenging conditions including bedding in very deep soils and also high groundwater levels. Use of HDPE as a large diameter trunk sewer was a first for Design South and Greenwood Metro and could possibly be the first installation of its kind in the United States. The installation process included electro-fusion welded joints that enabled the pipeline to become a complete monolithic system. This process virtually eliminates inflow and infiltration into the sewer.