Soil degradation is one of the most crucial problems humanity is facing. This is induced by the use of artificial fertilizers that disregards the input of organic matter in soil.
Moreover, phosphate fertilizers are predominantly sourced from phosphate rock – a resource that is declining in both quantity and quality. In this thesis phosphate and organic fertilizer recovery from black water was investigated.Currently, the soil application of black water sludge is prohibited in the Netherlands due to elevated heavy metal concentrations. However, the use of the same guidelines for sewage and black water can be argued, since heavy metals in black water mainly originate from feces (52%–84%) while in sewage the contribution of feces is less than 10%. A novel approach to simultaneously recover phosphate and energy was introduced by precipitation of calcium phosphate granules in anaerobic treatment of black water. Without any addition of chemicals, high purity calcium phosphate granules (≥95%) were produced in the sludge bed of the UASB reactor.