富磷剩余污泥厌氧消化过程中氮磷释放形态研究

Effect of Temperature and pH on Release of Nitrogen and Phosphorus during Anaerobic Digestion of Phosphorus-rich Waste Activated Sludge

通过静态厌氧消化试验,研究剩余污泥消化过程中pH与温度对氮磷释放形态的影响。结果表明,当pH=10.0时,消化过程中氮磷的释放程度均高于pH=5.0,在同等的pH情况下温度是氮磷释放的有利影响因素。温度对消化液中氮磷的存在形态影响较小,而pH则是影响氮磷形态的关键因素。pH=5.0时,NH4+-N是消化液中最主要的氮存在形态。当pH=10.0时,由于NH3的挥发作用,相当一部分氮从消化系统中损失,造成其NH4+-N低于pH=5.0。尽管在pH=10.0时比pH=5.0时有更多的磷释放,但pH=5.0时,消化系统中PO43--P的浓度却高于pH=10.0,其主要原因在于碱性条件下释放出的磷主要以聚合磷或其它结合磷为主。

Release of phosphorus and nitrogen during anaerobic digestion of phosphorus-rich waste activated sludge were evaluated with respect of the effect of temperature and pH value by operating 4 lab-scale anaerobic digesters. Just as the release of soluble chemical oxygen demand （SCOD） and solubilization of volatile suspend solids （VSS）, the forms of nitrogen and phosphorus released were shown to be substantially dependent on pH value rather than temperature. NI-I4＋-N was the most prevalent forms released at pH 5.0 conditions, Due to volatilization, the loss of nitrogen was the most prevalent forms at pH 10.0. Volatilization of NH4＋-N at pH 10.0 can answer for why NH4＋-N at pH 5.0 is higher than that at alkaline pH well. Although more phosphorus released at pH 10.0, the concentration of PO43--P at acidic pH was higher than that alkaline pH because most of the phosphorus released in supernatant at acidic pH existed in the forms of PO43--P.