RESIDUALS TREATMENT AT THE YUMA, AZ MAIN STREET WTP

The City of Yuma has implemented an Interim Mechanical Dewatering Facility, including a belt filter press, at the City's Main Street WTP to dewater residuals from the conventional WTP process. The interim facility replaces existing unlined solar drying beds, which were decommissioned to accommodate commercial development. The City fast-tracked the design and construction of the interim facility to bring the facility online before the drying beds were removed from service. The City used several strategies to accelerate the project schedule, including pre-procuring equipment and requiring a single supplier to provide all of the major equipment.Bench scale dewatering tests have indicated that the belt filter press system can achieve a dewatered residuals concentration of greater than 40 percent cake solids. Full-scale start-up and performance testing of the Interim Mechanical Dewatering Facility have not yet begun. The results of full-scale testing will be presented at the WEF/AWWA Joint Residuals and Biosolids Management Conference 2007, and design improvements and “lessons learned” will be discussed.