• 关键词：厌氧消化液  磷回收  磷酸铵镁结晶反应  碳酸根

• 基金项目：国家自然科学基金(No.51078339);中央级公益性科研院所基本科研业务专项(No.2011KYYW-01)

• 葛杰
• 1. 中国环境科学研究院, 城市水环境科技创新基地, 北京 100012;2. 北京林业大学, 环境科学与工程学院, 北京 100083

• 林郁
• 1. 中国环境科学研究院, 城市水环境科技创新基地, 北京 100012;2. 中国地质大学, 水资源与环境工程北京市重点实验室, 北京 100083

• 钱锋
• 中国环境科学研究院, 城市水环境科技创新基地, 北京 100012

• 宋永会
• 中国环境科学研究院, 城市水环境科技创新基地, 北京 100012

• 王毅力
• 北京林业大学, 环境科学与工程学院, 北京 100083

• 摘要：以模拟厌氧消化液为处理对象,进行了磷酸铵镁(MAP)结晶实验,考察了pH值、CO₃^2-、Ca²⁺以及CO₃^2-和Ca²⁺共存对磷酸铵镁结晶反应的影响;利用扫描电子显微镜(SEM-EDX)、X射线衍射(XRD)和傅里叶变换红外光谱(FTIR)对产物进行了表征.结果表明,随着pH值升高,磷的去除率显著提高,并在pH值为9.5时得到具有良好沉降性能的针状MAP晶体;CO₃^2-的存在会使磷去除率降低,在实验设定CO₃^2-浓度最大的条件下,磷去除率降低约17%,同时CO₃^2-会削弱Ca²⁺对MAP结晶反应的贡献,但并不改变MAP晶体形态和纯度;Ca²⁺存在则可以提高P去除率,但对MAP结晶反应抑制作用显著,当体系中n(Ca)/n(Mg)>0.65,产物主要以无定形磷酸钙盐为主;在Ca²⁺与CO₃^2-共存的体系中,Ca²⁺可有效地消除CO₃^2-对除磷效果的影响,随着两者浓度的增加,产物CaCO₃含量增多,磷酸盐则主要以MAP形式沉淀.

• Abstract：The effects of pH, carbonate (CO₃^2-), calcium (Ca²⁺) as well as coexistence of CO₃^2- and Ca²⁺ on the crystallization of magnesium ammonium phosphate (MAP) from simulated anaerobically digested effluent of wastewater were investigated. The morphology and composition of the obtained precipitate was observed and analyzed by Scanning Electron Microscopy with Energy Dispersive X-ray analysis (SEM-EDX), X-ray diffraction (XRD) and Fourier Transform Infrared Spectrometry (FTIR). The results showed that the phosphorus removal was significantly enhanced with the increase of pH value and good needle-like crystals were obtained. However, the existence of CO₃^2- reduced phosphorus removal. Under the experimental condition of the maximum CO₃^2- concentration, phosphorus removal decreased by 17% approximately. Simultaneously, CO₃^2- downgraded the contribution of Ca²⁺ to MAP reaction, however, it didn’t change MAP crystal shape and purity. On the contrary, the existence of Ca²⁺ improved phosphorus removal and had remarkable inhibitory effects on MAP reaction. The precipitated product was mainly amorphous calcium phosphate when Ca/Mg>0.65 in the system. In the coexistence system, Ca²⁺ effectively eliminated the influence of CO₃^2- on phosphorus removal. With the increase of concentration of both ions, CaCO₃ accounted for a large percentage and phosphate was primarily in MAP form.

• Key words：anaerobic digestion  phosphorus recovery  magnesium ammonium phosphate (MAP) crystallization reaction  carbonate

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