ARS | Publication request: Chemical phosphorus removal: A clean strategy for piggery wastewater management in Brazil

Submitted to: Environmental Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 30, 2011
Publication Date: January 31, 2012
Citation: Fernandes, G.W., Kunz, A., Steinmetz, R.L., Szogi, A.A., Vanotti, M.B., Flores, E.M., Dressler, V.L. 2012. Chemical phosphorus removal: A clean strategy for piggery wastewater management in Brazil. Environmental Technology. 33(14):1677-1683.

Interpretive Summary: The intensive production of animal protein is known to be an environmental polluting activity, especially if the wastewater produced is not managed properly. Swine production in Brazil is growing and technologies to manage all pollutants present in the wastewater effluent are needed. This work presents a case of study of phosphorus removal from piggery wastewater using lime and demonstrates the feasibility of this strategy for phosphorus management. The effluent of a swine manure treatment plant was treated with lime. With the addition of lime, the pH of the effluent ranged from 8.0 to 10 forming phosphorus sludge. Different conditions of sludge dewatering were evaluated and the chemical composition of sludge was investigated. Analysis of effluent samples showed that 92 percent of total phosphorus was in soluble form whereas mostly as phosphate. The efficiency of phosphorus removal was typically 90 percent at pH 8.5 and higher than 98 percent at pH 10.5. The sludge was separated by sedimentation, centrifugation or filtration and dried. The total phosphorus content on dried sludge was 9.3 percent. Further mineralogical analysis of the dry sludge showed the presence of amorphous compounds of Ca and P, which is an indication that the sludge obtained from the swine manure treatment has a potential for application as bio-fertilizer.

Technical Abstract: The intensive production of animal protein is known to be an environmental polluting activity, especially if the wastewater produced is not managed properly. Swine production in Brazil is growing and technologies to manage all pollutants present in the wastewater effluent are needed. This work presents a case of study of phosphorus (P) removal from piggery wastewater using calcium hydroxide and demonstrates the feasibility of this strategy for P management. The effluent of a swine manure treatment plant was treated with calcium hydroxide. According to the addition of calcium hydroxide, the pH of the effluent ranged from 8.0 to 10. Different conditions of sludge dewatering were evaluated and the chemical composition of sludge was investigated. Ion chromatography analysis of effluent samples showed that 92 percent of total P (TP) was present as soluble P (SP) whereas 75 percent of SP species were present as phosphate. The efficiency of P removal was typically 90 percent at pH 8.5 and higher than 98 percent at pH 10.5. The sludge was separated by sedimentation, centrifugation or filtration and dried. The TP content on dried sludge was 9.3 percent (w/w). X-Ray diffraction analysis of the dry sludge showed the presence of amorphous compounds of Ca and P, which is an indication that the sludge obtained from the swine manure treatment has a potential for application as bio-fertilizer.