Wastewater treatment currently focuses on removing phosphorus (P) and nitrogen (N) due to their potential to cause eutrophication in bodies of water. With growing concern for the longevity of global phosphate rock stores, however, there is now interest in recovering these nutrients. One method for recovering P and N is through the precipitation of struvite (magnesium ammonium phosphate) which also helps control unwanted struvite precipitation in pipes and on other surfaces at the treatment plant lessening a challenging maintenance problem, and produces a valuable alternative fertilizer product. A potential concern is that the environmental impacts struvite recovery creates through the use of additional chemicals and energy are not offset by its benefits. A life cycle assessment (LCA) case study of the full-scale wastewater treatment plant (WWTP) in Madison, WI USA was used to assess the environmental tradeoffs of struvite recovery in wastewater treatment. When only the struvite recovery system was considered, a portion of the environmental impact categories considered showed an overall environmental cost, while others showed a benefit, due to the phosphorus recovered. When the full scale WWTP was considered, there was an overall environmental impact to treating the wastewater, as there was prior to the struvite system deployment. However, due to the additional benefit of the struvite recovery, the overall environmental impacts of the WWTP are similar.

废水处理目前的重点是去除磷（P）和氮（N），因为它们可能引起水体富营养化。然而，随着人们对全球磷矿石储藏寿命的日益关注，现在人们对回收这些养分产生了兴趣。回收磷和氮的一种方法是通过鸟粪石（磷酸镁铵）的沉淀，这还有助于控制处理厂管道和其他表面上不需要的鸟粪石沉淀，从而减少了维护难题，并生产出有价值的替代肥料产品。潜在的担忧是鸟粪石回收通过使用其他化学物质而产生的环境影响，而能源并不能被其收益所抵消。美国威斯康星州麦迪逊市的大型废水处理厂（WWTP）的生命周期评估（LCA）案例研究用于评估废水处理中鸟粪石回收的环境权衡。仅考虑鸟粪石回收系统时，所考虑的部分环境影响类别显示了总体环境成本，而其他一些则由于回收了磷而显示出收益。当考虑到全面污水处理厂时，与鸟粪石系统部署之前一样，废水处理对整个环境产生了影响。但是，由于鸟粪石回收的额外好处，污水处理厂的总体环境影响是相似的。仅考虑鸟粪石回收系统时，考虑到的部分环境影响类别显示了总体环境成本，而其他一些则由于回收了磷而显示出收益。当考虑到全面污水处理厂时，与鸟粪石系统部署之前一样，废水处理对整个环境产生了影响。但是，由于鸟粪石回收的额外好处，污水处理厂的总体环境影响是相似的。仅考虑鸟粪石回收系统时，所考虑的部分环境影响类别显示了总体环境成本，而其他一些则由于回收了磷而显示出收益。当考虑到全面污水处理厂时，与鸟粪石系统部署之前一样，废水处理对整个环境产生了影响。但是，由于鸟粪石回收的额外好处，污水处理厂的整体环境影响是相似的。