Torva Riiska Wastewater Treatment Plant, Tõrva linn, Estonia

Torva Riiska is a former wastewater treatment plant located in Tõrva linn, Valga County, Estonia. The plant served a small population of 601 residents and is now closed. It was situated in the rural municipality of Tõrva vald, within the broader Valga maakond region. The plant provided secondary treatment, which is the standard biological treatment required under the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. Although the plant is closed, its designed capacity of 425 m³/day and actual discharge volume of 138.47 m³/day indicate it was sized for the local community. Estonia, as an EU member state, implements the directive, which mandates secondary treatment for inland discharges from populations under 10,000. The treated effluent from Torva Riiska would have discharged into local watercourses within the Gauja/Koiva river basin, which flows into the Baltic Sea. The plant's closure suggests that wastewater from Tõrva is now managed by a newer or consolidated facility, contributing to improved environmental protection in the region.

The plant's discharge likely entered the Õhne River, a tributary of the Emajõgi River, which flows into Lake Võrtsjärv and eventually the Baltic Sea via the Narva River. The region supports diverse aquatic life and is part of an important migratory corridor for fish. The closure of this plant may reduce nutrient loading, benefiting downstream ecosystems.