Efficiency and Mechanism of Pollutants Removal in Swine Wastewater by Coagulants

DOI: 10.5176/2251-189X_SEES18.17

Authors: Zhen-Xing Zhong, Lan Gao, Liu Fan, Saima Fazal, Rui Yan, Beiping Zhang

Abstract: Nutrient removal in the coagulation–flocculation process, applied to piggery wastewater has been studied. Poly-aluminum chloride (PAC), FeCl3, Al2(SO4)3 and KAl(SO4)2 were used as coagulants, and anionic polyacrylamide (PAM) was used as a coagulant aid. Throughout the experiments, coagulation–flocculation process was found to achieve high removal efficiencies for organic matter and phosphorus from the piggery wastewater. Results show that about 51-74{6e6090cdd558c53a8bc18225ef4499fead9160abd3419ad4f137e902b483c465} COD, 20-34.6{6e6090cdd558c53a8bc18225ef4499fead9160abd3419ad4f137e902b483c465} TN, 12-21{6e6090cdd558c53a8bc18225ef4499fead9160abd3419ad4f137e902b483c465} NH+ 4-N, and 44.4-76.1{6e6090cdd558c53a8bc18225ef4499fead9160abd3419ad4f137e902b483c465} orthophosphate (PO3- 4-P) in piggery wastewater was removed by the physicochemical treatment. Although the addition of PAM had no positive effect on the removal of TN and NH+ 4-N in piggery wastewater, it significantly enhanced the removal of PO3- 4-P by three aluminum coagulants. More interestingly, as for the removal of orthophosphate, the synergistic effects were present among three aluminum coagulants and PAM, while there was an antagonistic effect between FeCl3 and PAM.

Keywords: Swine wastewater; Coagulation-flocculation process; Coagulants; Nutrient removal;