Submitted to: ASABE Annual International Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 7/17/2016
Publication Date: N/A
Technical Abstract: This study evaluated the changes in sludge depth and volume of anaerobic swine lagoon in North Carolina after six years of applying treatment to the liquid flushed manure prior to entering the lagoon. The farm had seven swine barns with a permitted capacity of 5,145 head feeder to finish (735 head/barn). A traditional anaerobic lagoon system consisting of two lagoons of 0.6 hectare surface each was used for 11 to 12 years before the new treatment started. Lagoon 1 [depth = 2.74 meters (m), design volume = 13,120 cubic meters (m3)] received flushed manure from three barns, and lagoon 2 (depth = 3.66 meters, design volume = 16,552 m3) received effluent from four barns. The new treatment used high-rate solid-liquid separation with polymers and nutrient removal processes (biological nitrogen removal and phosphorus recovery) that treated all the flushed manure from 5,145 finishing swine operation. After the new treatment started, all the treated effluent was stored in lagoon 1, and lagoon 2 was discontinued and received only rainwater. The new treatment removed 97% of total suspended solids, 90% of volatile solids, 99% of BOD, 96% of TKN and 93% of TP from the flushed manure prior to entering lagoon 1. As plant effluent or rain water replaced the liquid in the two lagoons, they become aerobic (Eh > 300 millivolts). In the first two years of conversion, the ammonium concentration in the lagoons liquid was reduced from 370-485 mg/L to lower than 15. Before the conversion, the sludge in lagoon 1 accumulated to a depth 0.67 m (or 2,620 m3) in 11 years and sludge in lagoon 2 accumulated to a depth of 1.25 m (volume 4,440 m3) in 12 years. After conversion, the sludge accumulation on both lagoons was halted. During the six years of the new treatment, the sludge depth in lagoon 1 that received all the treated effluent stopped growing and was stabilized at a depth of 0.55 ± 0.07 m (volume = 2,100 ± 290 m3). Similarly, the sludge of lagoon 2 (discontinued lagoon) did not accumulate more sludge and remained about constant at a depth of 1.08 ± 0.05 m (volume = 3,750 ± 180 m3). Therefore, high-rate solid liquid separation and nutrient removal treatment of raw manure before entering the lagoon can halt sludge accumulation of swine lagoons.