Journal of Ecology and Rural Environment ›› 2010, Vol. 26 ›› Issue (3): 268-272.doi: CNKI:SUN:NCST.0.2010-03-019

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Technological Conditions for Application of MAP Crystallization Method to Remove Nitrogen and Phosphorus From Swine Farm Wastewater

SUN  Guo-Ping, ZHANG  Cong-Liang, WANG  Yan   

  1. School of Chemical Engineering and Energy,Zhengzhou University
  • Received:2009-07-24 Online:2010-05-25 Published:2011-04-01
  • Contact: WANG Yan School of Chemical Engineering and Energy,Zhengzhou University E-mail:wangyan371@zzu.edu.cn

Abstract: A systematic study was carried out to explore technological conditions for application of the magnesium ammonium phosphate(MAP) crystallization method using MgCl2·6H2O and Na2HPO4·12H2O as precipitant to remove N and P from wastewater of swine farms.It was found that the technology of regulating pH of the wastewater only called for an optimum pH range of 9.0-10.0,and aeration for 60 minutes as recommended to raise pH of the wastewater up to 8.9.Then it could remove 16.8%,78.4% and 21.4% of the ammonium-nitrogen,phosphorus and total nitrogen,respectively,in the wastewater.The magnesium-amending technology could effectively increase the phosphorus removal rate up to 95.4%,but it called for an optimum Mg∶P molar ratio of 1.6 and an optimum pH range of 9.0-10.0.The magnesium-and-phosphate-amending technology could have an ammonium-nitrogen removal rate as high as 87.4% and remove P till it was less than 10 mg·L-1 in concentration when the wastewater was regulated up to 9.5 in pH,1.0 in P∶N molar ratio and 1.1 in Mg∶N molar ratio.

Key words: swine wastewater, magnesium ammonium phosphate(MAP) crystallization, nitrogen, phosphorus, removal rate

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