Metlakatla Sewage Treatment + Disposal

Metlakatla is a First Nation community located on British Columbia’s North Coast. The Village of Metlakatla is located on Venn Passage about 10 km northwest of the City of Prince Rupert and is accessible only by water.

Before constructing this wastewater infrastructure, Metlakatla used two pump stations to discharge raw sewage into Venn Passage through a marine outfall.  The discharge of raw sewage did not meet Provincial and Federal Regulations, and the outfall location did not comply with provincial legislation relative to proximity to harvestable shellfish resources.  Therefore, there was a need to upgrade the wastewater system to comply with Provincial Regulations and to protect these resources.   

Metlakatla First Nation selected DNA to design and provide construction engineering services for a wastewater collection and treatment system to meet current regulations.  The feasibility study assessed sewage treatment technologies, sites available to build the sewage treatment infrastructure, and new marine discharge locations.  The final location of the treatment facility was chosen based on three main factors: the distance away from the community (to address odour and visual pollution concerns); the elevation (to allow for gravity discharge through the outfall pipe), and the soil conditions (substantially better than at alternative locations).

The project team selected an aerated lagoon treatment system to treat wastewater based on this treatment technology performance in other communities of similar size and location, operating complexity, and life cycle costs.  This treatment technology did require a larger land area (footprint) than other treatment systems.  However, the community decided that the benefits of this treatment system outweighed the additional land needed.

The scope of work for this project included: construction of an aerated sewage treatment facility, upgrades to roads, upgrades to two lift stations upgrades, installation of a forcemain and gravity forcemain, construction of a blower station, and construction of a new sewage outfall, protecting harvestable shellfish resources.