Douglas L. Smith (Indian Creek) Middle Basin WWTP, Solids Processing Improvement
The Middle Basin WWTP currently has an average daily flow capacity of 11.5 MGD. A project was recently completed that involved expansion and inclusion of nutrient removal in the liquids treatment process. This project, coupled with the move toward land application of the treated biosolids, has given rise to the need for upgrades and capacity increases to the solids processing facilities.
The HDR|Archer study evaluated the size and types of additional anaerobic digesters to meet future loading conditions. The feasibility and costs for producing Class A biosolids in the future were also investigated, as were expansion of the dewatering system, incorporation of a fats, oils and grease waste receiving and blending station, and the addition of a digester gas-fired co-generation facility.
Facility improvements included the replacement of the primary sludge degritting equipment, a fourth mesophilic anaerobic digester, replacement of the recirculation pumps and mixing systems, replacement of three existing hot water boilers with two larger capacity dual-fired boilers, a new fats, oils and grease waste receiving facility, a co-generation system with two 1-MW packaged units, a digester gas storage and cleaning system and incorporation of a state-of-the-art, plant-wide SCADA system
The project is estimated to result in $600,000 in annual cost savings including power savings and reductions in sludge hauling costs, and reduce annual greenhouse gas emissions by more than 9,700 metric tons from purchased power. Due to its status as a "green" project, ARRA funding was secured with 50 percent principal forgiveness for the "green: components of the project.