Effect of fermented swine wastes on biological nutrient removal in sequencing batch reactors

Fermented swine waste was compared to acetate for supplementation of bench-scale sequencing batch reactors (SBRs) to improve nutrient removal. Swine waste solids were fermented at room temperature for 10 days. The SBRs were fed diluted swine wastewater and operated on a cycle consisting of the following phases: 10-min anoxic fill, 13-h oxic, 7-h anoxic, 3-h oxic, 40-min settling, 10-min draw. Supplemental organic matter was added at the beginning of the anoxic phase. There was essentially no difference in performance of the reactors supplemented with either acetate or fermented swine waste: both achieved a total nitrogen removal of 90% and a total phosphorus removal of 89%. In comparison, a control reactor (receiving no supplementation) achieved total nitrogen and total phosphorus removals of 76 and 15%, respectively. Sludge phosphorus contents of the supplemented reactors were above 7% of volatile suspended solids, compared to sludge phosphorus content of less than 1% for the control reactor.