Grastorps avloppsreningsverk - Advanced Wastewater Treatment in Grästorp, Sweden

Grastorps avloppsreningsverk is an advanced wastewater treatment plant located in Grästorp, a town in Västra Götaland County, Sweden. The plant serves a population of approximately 4,625 people, classifying it as a small agglomeration under Swedish and EU regulations. Its designed capacity is 4,500 m³/day, and it currently discharges 726.04 m³/day of treated wastewater. The plant employs advanced treatment processes, which go beyond the secondary treatment required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. Advanced treatment typically includes nutrient removal (nitrogen and phosphorus) to protect sensitive receiving waters. The plant operates under Sweden's implementation of the directive, which mandates strict effluent standards for discharges into inland and coastal waters. The treated effluent is discharged into a local water body, likely a river or stream within the Göta älv drainage basin, which ultimately flows into the Kattegat sea area. The plant's proximity to the coast (within 10 km) means its discharge can affect coastal water quality. Advanced treatment helps minimize nutrient loading and protects the marine environment from eutrophication.

The plant discharges into a local watercourse within the Göta älv basin, which drains into the Kattegat, a sea area between Sweden and Denmark. This coastal region supports diverse marine life, including fish stocks and benthic habitats. The advanced treatment at Grastorps avloppsreningsverk reduces nutrient inputs, helping to prevent algal blooms and maintain water quality in the sensitive coastal ecosystem.