In 1999, two unused aeration basins (50 ft. x 100 ft. x 26 ft.) were modified to allow for Biological Nutrient Removal. The BNR process goal is to remove phosphorous without the addition of expensive chemicals. Baffle walls were installed to direct the flow into an N shaped path that increased the detention time in the basin, thereby creating anoxic conditions for the specialized bacteria required in the BNR process. Eight submersible mixers were added to each basin to keep the solids from settling in the basin. Detention time is 3.75 hours at average daily flow.

The four remaining aeration basins (50 ft. x 100 ft. x 26 ft. deep) each contain 1,500 submerged fine bubble diffusers. The high volume of air required is generated by two 350 hp variable vane turbine blowers. The blowers provide the mixing and oxygen necessary to maintain the Activated Sludge process. This process consists of providing the right environment for the bacteria and other microorganisms that consume the organic matter in the wastewater. Plant Operators monitor and adjust dissolved oxygen levels for proper treatment. Detention time in the aeration basins is 7.5 hours at average daily flow.