晶析辅助化学沉淀法处理高含磷废水

Treatment of High Concentration Phosphorus Wastewater by Crystallization-combined Chemical Preciptitation Process

在常温条件下,将价格低廉的氯化镁、碳酸氢铵加入到高浓度含磷废水中,不仅有较高的除磷率,且可兼得缓效复合肥MgNH4PO4·6H2O。为了使一次处理液能达标排放,以MgNH4PO4·6H2O作为晶种,采用晶析辅助化学沉淀法进一步除磷。在一次处理液放置时间为2.7h、水力停留时间维持0.1h左右的条件下,处理后的废水可达到Ⅱ类水排放标准(磷质量浓度不超过2.0mg/L)。

The phosphorus in high concentration phosphorus wastewater not only can be efficiently removed by adding cheap MgCl 2·6H 2O and NH 4HCO 3 at room remperature,but also a slow releasing compound fertilizer(MgNH 4PO 4·6H 2O)can be obtained at the same time.Then the wastewater can be further treated by crystallization precipitation using MgNH 4PO 4·6H 2O as crystal seeds in order to make the primary effluent meet the national discharge standard.After 2 h of primary wastewater depositing and with about HRT 0.1 h,the secondary effluent can meet the second grade discharge standard(phosphorus mass concentration is less than 2.0 mg/L).