THIVERVAL GRIGNON Wastewater Treatment Plant, Thiverval-Grignon, France

THIVERVAL GRIGNON is a wastewater treatment plant located in Thiverval-Grignon, a commune in the Yvelines department of Île-de-France, France. The plant serves a population of approximately 7,067 people, placing it in the small agglomeration category under EU regulations. As a French facility, the plant operates under the EU Urban Waste Water Treatment Directive 91/271/EEC, which requires appropriate treatment for agglomerations of this size. Plants serving populations between 2,000 and 10,000 typically employ secondary treatment or equivalent to meet effluent quality standards. The plant discharges treated water into the local watershed, which ultimately drains into the Seine River basin. The Seine flows through Paris and into the English Channel, supporting diverse aquatic ecosystems and providing water for agricultural and recreational uses downstream.

The plant's treated effluent enters the local water system within the Seine River basin, which drains a large portion of northern France. The Seine flows northwest through Paris and eventually reaches the English Channel near Le Havre. This watershed supports diverse aquatic life, including fish species such as pike and perch, and provides critical habitat for migratory birds along the river corridor.