Submitted to: Waste to Worth Conference
Publication Type: Proceedings
Publication Acceptance Date: 3/12/2017
Publication Date: 3/17/2017
Citation: Szogi, A.A., Vanotti, M.B., Shumaker, P.D. 2017. Phosphorus recovery from anaerobic swine lagoon sludge using the quick wash process. In: Proceedings of Waste to Worth Conference, April 17-20, 2017, Durham, North Carolina. 0.
Technical Abstract: Long term accumulation of sludge in anaerobic swine lagoons reduces its storage volume and ability to treat waste. Usually, excess accumulation of lagoon sludge is removed using pumping dredges. The dredged sludge is then land applied at agronomic rates according to its nutrient content. The accumulation of phosphorus (P) in the sludge requires the largest acreage for its land application based on crop agronomic requirements. Therefore, nutrient management plans may limit application to crop or pastureland near the animal facility avoid soil P build up in excess of soil and crop assimilative capacities. Although dewatered sludge can be moved off the farm, its transportation becomes less economical with increasing distances from the source. An option is to extract and recover P in a concentrated form to economically transfer this nutrient to P-poor croplands. A patented treatment process, called Quick Wash (QW), developed by USDA-ARS for extraction and recovery of P from animal manure solids was tested for recovery of P from anaerobic swine lagoon sludge. With the QW process, P was extracted in solution from dredged sludge by mixing the sludge with sulfuric acid prior to dewatering using polymer enhanced mechanical solid-liquid separation. Following, P was recovered by addition of liquid lime and an anionic flocculent to the separated liquid extract to form a calcium-containing P precipitate. The QW process generates two solid products: 1) sludge solids low in P; and 2) a concentrated P material. While most of the nitrogen and carbon was left in the washed sludge solids, the QW process extracted and recovered as much as 90 percent of the P from sludge solids. From results of a pilot field test, the P grade of the recovered material was in the range of 24.0 - 30.5 % phosphorus pentoxide (P2O5). The inclusion of this process in a lagoon sludge management plan offers producers an opportunity to locally land-apply the low-P sludge as a carbon-rich soil amendment and recycling recovered P as a valuable product.