Physical and Chemical Properties of Screened-flushed Pig Slurry Waste

The properties of screened-flushed pig slurry waste using ASTM standard sieve numbers 5 (4· 000 mm), 10 (2·000 mm), 18 (0·980 mm), 35 (0·500 mm), 60 (0·250 mm) and 140 (0·106 mm) are reported. Five replications of the flushed waste obtained at the Auburn University Swine Research Unit were used in the screening study. The analysis performed to determine the physical and chemical properties of the material retained on each sieve include total solids (TS), volatile solids (VS), fixed solids (FS), total Kjeldahl nitrogen (TKN-N), total ammonia (NH3-N), organic nitrogen (ON-N), total carbon (TC), chemical oxygen demand (COD), total- and orthophosphate (TP and OP). A mass balance was calculated from the results of the analysis which showed that approximately 60% of the organic material (as measured by VS), 30% of TKN-N, 10% of NH3-N and 20% of ortho-PO4-P was retained on the No. 140 screen using multi-level screening. Separation of these components is useful when anaerobic digestion or single-cell protein production using algae are integrated into one waste utilization system. Nutrient retention in the solid fraction will also reduce the land area needed for liquid disposal and concentrate the material for reduced handling.