Belt Filter Press Produces Similar Performance to Centrifugation: Side-By-Side Dewatering Results from three Anaerobic Digested Biosolids

The recent Biosolids Management Plant conducted by the Ocean County Utilities Authority (OCUA) recommended side-by-side pilot testing of belt filter press and centrifuge technology to select the best technology to dewater their anaerobically digested biosolids from the authority three plants. Initially, screening of available vendors for providing dewatering technologies and conducting the side-by-side piloting were conducted and two vendors were selected: 0.6 meter Wiklepress of Ashbrook and skid mounted ALDEC 406 centrifuge of Alfa Laval. A detailed pilot testing protocol for both technologies and guidance support documents including all necessary support from both vendors and the OCUA staff to achieve successful testing were finalized prior to conducting the testing.The testing protocol called for one week testing at each plant. The testing protocol was consistent for all plants. Side-by-side testing commenced on May 7th and ended on May 25th, 2007. The performance of each technology was measured through achieving consistent cake solids at the end of testing at each facility with a certain polymer dose and percent solids recovery higher than 95%. Based on the obtained cake solids with the used polymer dose, and the electricity consumed for dewatering during the consistent performance testing, the operating costs for each technology were estimated.The testing showed that the belt filter press technology produced similar performance to the centrifuge at all three plants and in some cases using lower polymer doses to achieve the same cake dryness. Based on estimated operating costs, BFP technology was recommended to dewatering biosolids at all three facilities.