State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
J Environ Sci (China). 2012;24(8):1533-8. doi: 10.1016/s1001-0742(11)60969-8.
Phosphorus (P) is an element vital for all living organisms, yet the world's reserves of phosphate rock are becoming depleted. This study investigated an effective P recovery method from sludge ash via struvite precipitation. Results showed that more than 95% of the total P content was extracted from sludge ash by applying 0.5 mol/L HCl at a liquid/solid ratio of 50 mL/g. Although heavy metal leaching also occurred during P extraction, cation exchange resin efficiently removed the heavy metals from the P-rich solution. Orthogonal tests showed that the optimal parameters for P precipitation as struvite would be a Mg:N:P molar ratio of 1.6:1.6:1 at pH 10.0. X-ray diffraction analysis validated the formation of struvite. Further investigations revealed that the harvested precipitate had a high struvite content (97%), high P bioavailability (94%), and low heavy metal content, which could be considered a high quality fertilizer.
磷（P）是所有生物都必不可少的元素，但世界上的磷矿储量正在枯竭。本研究通过鸟粪石沉淀探讨了一种从污泥灰中有效回收磷的方法。结果表明，通过在液固比为 50 毫升/克的条件下使用 0.5 摩尔/升的 HCl，从污泥灰中提取了超过 95%的总磷含量。尽管在提取 P 的过程中也发生了重金属浸出，但阳离子交换树脂可有效地从富含 P 的溶液中去除重金属。正交试验表明，以鸟粪石形式沉淀 P 的最佳参数为 Mg:N:P 的摩尔比为 1.6:1.6:1，pH 值为 10.0。X 射线衍射分析验证了鸟粪石的形成。进一步的研究表明，收获的沉淀物具有高的鸟粪石含量（97%）、高的 P 生物有效性（94%）和低的重金属含量，可以被认为是一种高质量的肥料。
