Erglu NAI Bio Q 400 Wastewater Treatment Plant, Ergli pagasts, Latvia

Erglu NAI Bio Q 400 is a wastewater treatment plant located in Ergli pagasts, Madonas novads, Latvia. It serves a population of approximately 2,097 people, placing it in the small agglomeration category under EU regulations. The plant provided secondary treatment, which is the standard required by the EU Urban Waste Water Treatment Directive for inland freshwater discharges. The plant's designed capacity was 3,310 m³/day, with a reported discharge volume of 138.17 m³/day. As a secondary treatment facility, it utilized biological processes to reduce organic matter and suspended solids before discharge. The plant is now closed, and its operational status is listed as closed. The plant's discharge likely entered local watercourses within the Daugava River basin, which flows into the Gulf of Riga in the Baltic Sea. The surrounding area is rural, with agriculture and forestry as primary land uses.

The plant is located inland in central Latvia, within the Daugava River basin. Treated effluent would have discharged into small streams or rivers that eventually flow into the Daugava River, which empties into the Gulf of Riga, part of the Baltic Sea. The Baltic Sea is a sensitive brackish water body with eutrophication challenges, making nutrient removal important for wastewater discharges in the region.