UWWTP De Groote Zaag - Krimpen aan de Lek Wastewater Treatment Plant

UWWTP De Groote Zaag is a municipal wastewater treatment plant located in Krimpen aan de Lek, a town in the province of Zuid-Holland, Netherlands. The plant serves a population of approximately 41,000, placing it within the medium agglomeration category under EU classification. As a Dutch facility, the plant operates under the EU Urban Waste Water Treatment Directive 91/271/EEC, which requires secondary treatment for agglomerations of this size. The Netherlands enforces stringent national standards that often exceed EU minimums, including advanced nutrient removal to protect sensitive water bodies. The plant's designed capacity is 1.00 (likely in thousands of cubic meters per day), indicating a moderate-scale facility. The treated effluent is discharged into the Lek River, a distributary of the Rhine, which flows westward through the Rhine-Meuse-Scheldt delta to the North Sea. This region is ecologically significant, supporting diverse aquatic life and serving as a critical migratory corridor for fish. The plant plays a key role in maintaining water quality in this densely populated and agriculturally intensive delta area.

The Lek River carries treated effluent from the plant downstream through the Rhine-Meuse delta, eventually reaching the North Sea. This delta is a dynamic estuarine environment that supports diverse aquatic species and serves as an important stopover for migratory birds. The plant's nutrient removal performance is critical to preventing eutrophication in the downstream coastal zone, which is subject to strict water quality targets under the EU Water Framework Directive.