Research on nutrient removal andrecovery from swine wastewater in China

摘要

Heavy pollution of livestock and poultry wastewater has been a problem inChina. It is already noticed that nutrient removal is necessary for water environmentprotection, but nutrient recovery is still a rather fresh topic. In the present study, researchon nutrient removal and recovery by magnesium ammonium phosphate (MAP) from swinewastewater was carried out at bench and pilot scale. It showed that for MAP crystallizationthe optimum pH value was at 9.0–10.0, the coexistence of Ca in solution would increasethe P removal efficiency, but would affect the morphology of MAP; the coexistence ofcarbonate would slightly decrease the crystallization efficiency of MAP. The pilot scaleexperiments of 10 m 3 /d in the piggery showed that both discontinuous and continuous flowMAP crystallization reactors were efficient for phosphorus (P) removal and recovery fromanaerobically treated swine wastewater, while the discontinuous reactor was more efficient;the reactors were resistant to temperature variation in the range of 12 to 30°C and to influentphosphorus concentration variation in the range of 30 to 80 mg/L; the effiuent P concentrationcould meet the national discharge standard of livestock and poultry wastewater. Ammoniacould be also removed with MAP crystallization, but more ammonia was removed bycarbonate stripping for pH increase purpose instead of the MAP crystallization reaction.