以鸟粪石形式从剩余污泥中回收氮和磷

摘要

以鸟粪石形式从固体废弃物——剩余污泥中回收氮磷,探讨pH值和发酵时间对污泥发酵溶出氮和磷的影响,以及Mg和P摩尔比对回收磷的影响.结果表明:在强酸或强碱条件下,溶出的氮、磷的质量浓度较高,而且随着发酵时间延长,发酵液中氨氮与正磷酸盐质量浓度增加,其最佳发酵时间为2d.此外,随着投加镁的增加,氮磷回收率增加,当发酵液中Mg和P的摩尔比为1.2∶1时,磷的回收率最高.对回收产物进行组分分析、电镜扫描与X射线衍射分析,证明沉淀主要成分为鸟粪石.%The recovery of nitrogen and phosphorus from solid waste-excess sludge by the form of struvite was studied.The effect of pH and fermentation time on the concentrations of ammonia-nitrogen and orthophosphate were investigated.The effect of molar ratio of n(Mg):n(P) on the recovery rate of phosphorus was also investigated.The results indicated that higher concentrations of ammonia-nitrogen and orthophosphate were observed when sludge fermented at strong acid or base conditions,respectively.With fermentation time prolonged,the mass concentrations of ammonia-nitrogen and orthophosphate increased.The optimum fermentation time was 2 d.In addition,the recovery rate of nitrogen and phosphorus increased with the increasing magnesium.The phosphorus recovery rate was highest when the molar ratio of n(Mg):n(P) was 1.2 ∶ 1.Component analysis,scanning electron microscope and X-ray diffraction results showed that the recovered product mainly composed of struvite.