The City of St. James received a state mandated phosphorous limit for the discharge from its wastewater treatment facility. The phosphorous limit is the result of a total maximum daily load study for dissolved oxygen in the Minnesota River.
Stantec was selected to design improvements to the city’s wastewater treatment facility to meet the effluent phosphorous limit and provide improvements to other processes. Improvements included modifications to the grit removal system, activated sludge process, biosolids storage and processing, disinfection system, and upgrades to the process aeration system.
Throughout the design of the improvements, Stantec and city staff achieved efficient design by maximizing use of existing structures. The biological nutrient removal system, the biosolids belt press, administration building modifications, and the UV disinfection system were all constructed within existing structures, reducing construction costs and increasing energy efficiency.
The improved biological nutrient removal process has produced effluent with acceptable phosphorus levels, resulting in savings of up to $2,000 per month in chemical costs for the city.