Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, Fujian 361021, China.
Water Sci Technol. 2011;64(2):334-40. doi: 10.2166/wst.2011.720.
Recovering nitrogen and phosphorus through struvite (MgNH4PO4 6H2O) crystallization from swine wastewater has gained increasing interest. However, swine wastewater contains complex compositions, which may hinder the formation of struvite crystal and affect the purity of the precipitates by forming other insoluble minerals. In this work, experiments were carried out to evaluate struvite precipitation in the anaerobically digested swine wastewater, with dosing bittern as a low-cost magnesium source. Exceeded 90% phosphate removal and 23-29% ammonium reduction were obtained. FTIR, XRD and mass balance analysis were combined to analyze the species of precipitated minerals. Results showed that the precipitates were struvite, mixed with amorphous calcium phosphate (ACP) and brucite. The presence of Ca2+ diminished the percentage of struvite and gave rise to ACP formation. Controlling pH below 9.5 and bittern dosage above 1% (w/w) could inhibit ACP precipitation and harvest a highly pure struvite crystal product.
从猪废水中通过鸟粪石（MgNH4PO4·6H2O）结晶回收氮和磷已经引起了越来越多的关注。然而，猪废水中含有复杂的成分，这些成分可能会阻碍鸟粪石晶体的形成，并通过形成其他不溶性矿物来影响沉淀物的纯度。在这项工作中，进行了实验以评估投加苦卤作为低成本镁源的厌氧消化猪废水中的鸟粪石沉淀。获得了超过 90%的磷酸盐去除率和 23-29%的铵减少率。傅里叶变换红外光谱（FTIR）、X 射线衍射（XRD）和质量平衡分析相结合，分析了沉淀矿物的种类。结果表明，沉淀物为鸟粪石，与无定形磷酸钙（ACP）和水镁石混合。Ca2+的存在降低了鸟粪石的百分比，并导致 ACP 的形成。控制 pH 值低于 9.5 和苦卤用量高于 1%（w/w）可以抑制 ACP 的沉淀，从而获得高纯度的鸟粪石晶体产物。
