Phosphate can be removed biologically and/or chemically in small wastewater treatment plants. The basis of biological phosphate elimination is the ability of certain bacteria to store more phosphate as polyphosphate in the presence of oxygen. If they do not find oxygen in their environment, the polyphosphate is released from the cells again and serves as an energy source. Bacterial growth is inhibited during this phase. During the renewed transition to a phase with sufficient oxygen, the stored substances serve as energy for rapid adaptation and the start of metabolic and growth processes. The energy gain achieved in this process in turn serves for the uptake and incorporation of phosphate. However, these biological processes are often not enough to sufficiently reduce the phosphate content in wastewater.  Excessive discharge of phosphorus compounds into the waterbodies leads to increased availability of the nutrient. This can lead to increased growth of algae and small organisms in water bodies (eutrophication). As a result, toxic substances are formed and the balance and quality of the water body is significantly affected. 

Therefore, measures to reduce this environmental pollution by chemical phosphate elimination are often indispensable to protect the ecological balance in the long term.