The City of Delphos is a Combined Sewer Overflow (CSO) community and EPA orders included preparation of a Long Term Control Plan (LTCP). Following modifications, completion and approval of the Wastewater Compliance Plan (LTCP), the team of CT Consultants and Floyd Browne Associates prepared plans and specifications for WWTP Improvements. CT served as the senior project manager and also the environmental engineer responsible for the solids process design, electrical, mechanical and architectural design as well as a portion of the structural design.
For a community with a population of 7,200 the Delphos Wastewater Treatment Plant experienced large variations in plant flow due to the City’s CSOs. In addition to these large swings in flow, the City also contains several food processing industries regularly driving the organic loading to a level equivalent to a community with a population of 75,000 and a population of 120,000 when combined with the CSO hydraulic loadings. The final design has resulted in a new Wastewater Treatment Plant with a 3.83 MGD average daily design flow with capacity to meet a 12.0 MGD peak flow. The design also contained provisions to increase the plant to a future average daily flow of 8.0 MGD and peak of 18.0 MGD. Project improvements include state-of-the-art MBR activated sludge technology with biological phosphorus removal supplemented by chemical addition. Class “A” solids stabilization is conducted by an Autothermal Thermophilic Aerobic Digestion (ATAD) process. The design provides for future total nitrogen reduction to meet future TMDL effluent limits.
The Delphos WWTP was the recipient of an Honor Award in Engineering Excellence Awards presented by ACEC of Ohio.