Biological Nutrient Removal With Advanced Primary Treatment

In biological nutrient removal (BNR) systems, conventional primary treatment is typically used to settled out between 40% to 60% of total suspended solids (TSS) and reduces biological oxygen demand (BOD) by 20% to 35%. Advanced primary treatment is defined as achieving greater than 80% and 45% TSS and BOD removal, respectively. Historically, the industry has done advanced primary treatment by the addition of coagulants and polymers to increase settling and/or flocs, which adds to operating costs and sludge production.

Recent advancements in filtration allow advanced primary treatment to be achieved without coagulant addition. Advanced primary treatment has been around for nearly a decade, but recently there has been a significant shift acceptance and adoption. Utilizing pile cloth media filtration (PCMF) systems, advanced primary treatment can significantly increase settled solids without the use of chemical additions, all while reducing capital and operating costs, ensuring more consistent effluent, and increasing flow capacity.