Start-Up and Operations of the City of Delphos MBR/ThermAer ATAD Wastewater Treatment Facility

The City of Delphos, Ohio along with their engineers designed a new state-of-the-art wastewater treatment plant utilizing flat plate membrane (MBR) technology (Enviroquip/Kubota) coupled with an autothermal thermophilic aerobic digestion (ATAD) 2nd generation (ThermAer™) solids treatment system to address the current and future needs of the city as well as the Directors Final Findings and Orders (DFFOs) filed against the city by the Ohio Environmental Protection Agency (EPA). The city received funding for this project from the Ohio EPA's Division of Environmental and Financial Assistance (DEFA). The plant has a design average day flow of 3.83 MGD (14,500 m3/day) with a peak 48-hour flow of 12 MGD (45,500 m3/ day). The average dry weather flow is 1.5 MGD (5,700 m3/day). The ATAD system is designed for a solids loading of 8,700 lbs/day (4,000 kg/day). The community has a 70% combined sanitary sewer system with seven permitted combined sewer overflows.The entire project included the following: an addition to an existing equalization basin bringing the total storm equalization capacity of the system to 12 million gallons (14,500 cubic meters); a new pumping station with course screens at the existing plant with two 18-inch (450 mm) force mains to pump the flow to the new plant site; a headworks building with fine screening and grit and grease removal; a septage receiving station; a membrane bioreactor using flat plate technology; vertical ultraviolet (UV) disinfection system; ThermAer ATAD (Class A or exceptional quality) solids handling system with gravity belt/ belt press units; SCADA control system; new administration building with offices, laboratory and vehicle storage and demolition of the existing facilities.This paper and presentation will briefly describe the design of this new facility and the decision process behind going with an MBR and moving from a Class B to Class A wastewater solids treatment process; however, it will focus mainly on the first 18 months of operations and maintenance at the facility. The author will discuss the basic operations of the MBR system and the detailed start-up and operations of the ThermAer ATAD system focusing on training, staffing requirements, and operational costs and benefits of utilizing these two treatment technologies to meet strict effluent limits for (carbonaceous biochemical oxygen demand 5 day (CBOD5), nitrogen ammonia and phosphorus brought on by a recent total maximum daily load (TMDL) study while producing an exceptional quality biosolids product that is being utilized within the community. The paper and presentation will include data associated with the ATAD system such as percent total solids and percent volatile solids destruction, and percent total solids of the exceptional quality cake product being utilized for land application. Polymer and alum dosage rates and associated costs for each system will also be discussed.