Research Center for Environmental Quality Manangement, Kyoto University, 1-2 Yumihama, Otsu City, Shiga 520-0811, Japan.
Environ Technol. 2011 May-Jun;32(7-8):693-8. doi: 10.1080/09593330.2010.510537.
Increased population growth and food prices have resulted in more demand for fertilizers, especially phosphorus (P), to be used in agriculture and production of food crops. This research investigated the feasibility of P recovery from selected wastewaters in the form of precipitates only with pH adjustment. Human urine and effluent of an anaerobic digester treating a piggery's wastewater were employed to determine appropriate pH conditions for P recovery including solubility of the precipitates in an agricultural soil. From the laboratory experiments, the highest P recovery was found to be 106 mg per one litre of urine at pH 11. Due to its lower P content, the highest P recovery from one litre of the anaerobic digester effluent was 39 mg at pH 9. The X-ray diffraction analysis of the precipitates identified them to consist of struvite, syn-NH4MgPO4 6H2O, and other precipitate compounds consisting of CaCO3, NaCl and Mg3Al2(SiO4)3 and P contents of the precipitate samples were found to be 3-7%. When mixed with soils at a moisture content of 50%, the extents of P solubilized from the precipitate samples were in the range of 50-60%. Application of these experimental results to full-scale operation for P recovery is suggested.
人口增长和食品价格的上涨导致对肥料的需求增加，特别是磷（P），用于农业和粮食作物的生产。这项研究调查了仅通过 pH 值调整以沉淀物的形式从选定废水中回收磷的可行性。用人尿和处理猪场废水的厌氧消化器的流出物来确定用于磷回收的合适 pH 值条件，包括沉淀物在农业土壤中的溶解度。从实验室实验中发现，在 pH 值为 11 时，每升尿液中最高可回收 106 毫克磷。由于其磷含量较低，在 pH 值为 9 时，每升厌氧消化器废水中最高可回收 39 毫克磷。沉淀物的 X 射线衍射分析表明，它们由鸟粪石、syn-NH4MgPO4 6H2O 和由 CaCO3、NaCl 和 Mg3Al2(SiO4)3 组成的其他沉淀物化合物组成，沉淀物样品中的磷含量为 3-7%。当与土壤以 50%的水分含量混合时，从沉淀物样品中溶解的磷的程度在 50-60%之间。建议将这些实验结果应用于磷回收的实际规模操作。
