Lagoon Wastewater Treatment Plant, Mistissini, Eeyou Istchee Baie-James, Québec

The Lagoon wastewater treatment plant is located in Mistissini, a Cree community within the Eeyou Istchee Baie-James territory in northern Québec, Canada. The plant serves a population of approximately 3,341 residents and is part of the region's municipal wastewater infrastructure. As a lagoon-based system, the plant relies on natural treatment processes typical for small, remote communities. Under Canadian federal and provincial regulations, such facilities are designed to meet effluent quality standards set by Environment Canada and the Québec Ministry of the Environment. The plant's designed capacity is 1.00 million litres per day, reflecting the scale of the community it serves. The treated effluent is discharged into the local watershed, which ultimately drains into the Rupert River system and then into James Bay. This region is ecologically sensitive, supporting diverse aquatic life and serving as an important migratory corridor for fish and waterfowl. The plant's operation plays a key role in protecting downstream water quality.

The plant discharges into the Rupert River watershed, which flows into James Bay, a southern extension of Hudson Bay. This area supports a rich ecosystem including boreal forest wetlands, fish species such as lake sturgeon and brook trout, and migratory birds. Protecting water quality is critical for the health of these habitats and the traditional Cree way of life.