Wastewater recovered struvite: Quality assessment for heavy metals, PFAS, and microplastic

The transition to circular economy in the water sector includes an increased focus on the recovery of nutrients, such as phosphorous, present in various streams of the municipal sewage treatment plants. However, recovered nutrient-rich products, such as struvite, may contain unwanted impurities and micropollutants. The content of emerging contaminants in fertilizers is particularly dangerous from the point of view of toxic substances migration and its negative impact on the environment. Therefore, the aim of the presented research was to determine the content of the selected impurities and micropollutants in tested struvite precipitated in controlled laboratory conditions and in struvite naturally precipitated in technical equipment of large sewage treatment plant. The scope of the analyses included the content of heavy metals, PFAS compounds and microplastics. The laboratory derived struvite had complied with the relevant heavy metals and PFAS limits, whereas the technical struvite had a non-compliance for one of the heavy metals. The research results indicated the potential risk of struvite contamination with heavy metals and micropollutants.