APRIL 2016 — The City of St. Joseph, Missouri, has a metropolitan population of 128,000 people. The City and the majority of its surrounding area is served by a single wastewater treatment facility, the Water Protection Facility (WPF). The facility neighbors heavy industrial and food processing plants and is adjacent to the Missouri River, which serves as its discharge location. This secondary treatment facility is currently permitted for an average design flow of 27 million gallons per day (MGD). It is fed domestic, commercial, and industrial wastewater by a separated sewer system on the east side of the City and a combined sewer system on the west side. Additionally, three industrial plants send pre-treated industrial waste directly to the facility.
With ammonia limits becoming more stringent, two studies were commissioned by the City to analyze their processes. First, a facilities plan study, followed by a study to further evaluate improvements to the WPF that would address anticipated ammonia limits. Based on the analysis, the City determined that upgrades would be required to meet future regulatory requirements, such as the need for nitrogen and phosphorus removal. This prompted the Ammonia Removal Improvements, a $50 million project consisting of improving ammonia removal, adding a BioSolids dryer facility, and replacing an aging headworks and grit facility.
Garney is currently serving as the wastewater treatment plant contractor to improve the existing facility to meet initial ammonia limits, while the overall goal is to address future, more stringent, effluent limits for ammonia, total phosphorous, and total nitrogen.
Improvements to the facility consist of separating the industrial and domestic influent flows, creating two trains within the plant. The domestic aeration basins are a BNR A20 process for biological nutrient removal, which were installed in the existing aeration basins. The industrial process is an activated sludge BNR system, featuring a five-stage Bardenpho process. Construction of the industrial aeration basin was a significant undertaking as the existing tank, originally constructed for aerobic digestion, was to be reused. The inside of this tank, approximately the size of a football field, was completely reconstructed and increased in size vertically to allow greater volume and provide sufficient hydraulic head for ammonia removal and future nitrogen removal process.
This two train system allows the large industrial flows to skip treatment at the plant and reduces the need for air, making the system more efficient. Improvements at the facility are set to be completed by August 2016.