Nakusp Wastewater Outfall (Past Project)

Project Category: Wastewater

In 2007 Delterra Engineering staff recognized that the Nakusp STP system was failing, and that the infiltration beds for disposing of Village wastewater were at risk of plugging within a short time.    We realized that the STP could flow by gravity to the Arrow Lake, and with appropriate treatment the wastewater could discharge into the Arrow lake system with 1 Million liters/second flowing by,   to dilute the 12 liters/second from the Village.     It was difficult to obtain approval from MOE, but they were convinced in the end that additional nitrogen and phosphorous would be beneficial to the nutrient deficient (oligotrophic) lake, and that the wastewater will meet the Municipal Wastewater Regulation.   Delterra completed all the Federal and Provincial environmental studies, including a Lake Water Quality study and plume analysis.

The project was increased to include 450m of outfall into the lake, as Council rezoned the adjacent property from Industrial to Resort/Residential during the project.    This increased the outfall distance from about 40m to 450m.    In the end it is safer to have the outfall deep and far from shore.   

The pipe was floated into position and slowly filled with water to allow the weights to carry the outfall to the lake bottom.   Village staff worked hard to construct the concrete weights to sink the pipe.