This is an activated sludge wastewater system serving a small municipality of approximately 16,000 residents. The North Basin is the main reactor basin where aeration is supplied for mixing. 

The North Basin utilized 240 hp of aeration to keep total suspended solids in the 3,000 to 4,000 mg/L range. Excess aeration to keep sufficient TSS created dissolved oxygen concentrations unnecessarily high at 6-7 mg/L (instead of a more appropriate concentration of around 1-2 mg/L). The oxygen transfer rate is almost zero at these levels, yet the aeration could not be turned down because TSS concentrations would drop too low. As a result, the municipality had very high energy costs.

Objective: Reduce high-horsepower aeration system operation time for energy and cost savings.

Download the case study to learn more.