Maximizing Existing Treatment Capacity through Flow Consolidation

The City of Anderson, Indiana used their CSO Long Term Control Plan (LTCP) as a mechanism to update their aging wastewater treatment facility as well as reducing their combined sewer overflows (CSO) and did so by maximizing the use of existing facilities to minimize capital costs. Because of “dilute” influent raw sewage the selected plan included the following components: Eliminating the existing primary treatment process for both New Plant and Old Plant, consolidating influent flow to one preliminary treatment facility, “decoupling” the existing New Plant primary clarifiers and converting them to “primary treatment” for wet weather flows only, converting the existing Old Plant primary clarifiers to aeration tanks to increase biological treatment capacity and use of existing biotowers for biological treatment of wet weather flows.. The selected facilities plan allowed the City to utilize the excess capacity of existing facilities while providing minimal new facilities in order to meet their goals.