【摘要】 镁源已经成为尿液废水鸟粪石沉淀法的主要成本之一。探索以海水和苦卤水作为廉价镁源的可行性。在优化pH值、n(Mg)∶n(P)、搅拌转速、反应时间和沉降时间等条件后,海水和苦卤水作为镁源均可实现磷的高效去除。海水中镁的利用率为98%,n(Mg)∶n(P)为1即可去除96%的磷,但是沉淀产物中存在碳酸镁钙杂质。苦卤水中镁的利用率仅为75%,n(Mg)∶n(P)为1. 5时可实现98%的磷去除,并且鸟粪石纯度更高。苦卤水中镁浓度更高使得其投加量仅为海水的5%,因此可作为一种更适宜的廉价镁源。更多还原

【Abstract】 Magnesium source was considered as one of the key cost factors for using the struvite precipitation process to recover phosphate from urine wastewater. This study investigated the feasibility of using seawater and bittern as the cheap magnesium sources for the process. Results showed that both seawater and bittern can effectively remove most of the phosphate from urine wastewater at optimized conditions including pH,n( Mg) ∶ n( P) molar ratio,stirring speed,reaction time and settlement time. The use efficiency of magnesium in seawater was 98%,and about 96% of the phosphate was removed at a n( Mg) ∶n( P) ratio of 1. However,the precipitates obtained through seawater had impurities due to the formation of magnesium-calcite.The removal efficiency of phosphate could reach 98% at a n( Mg) ∶ n( P) ratio of 1. 5 for bittern because of its low magnesium use efficiency( 75%),while purer precipitates could be yielded in the process. The dosage of bittern was much lower than that of seawater because the concentration of magnesium in bittern was much higher. Therefore,the bittern was proved to be a more suitable cheap source of magnesium for struvite precipitation.更多还原