Innovative Mixing with Aeration at Mt Gilead WWTP

The Mt. Gilead WWTP, an activated sludge facility, expanded capacity to include revisions both primary and secondary treatment processes as well as the biosolids handling for the proposed .82 MGD facility. The Poggemeyer Design Group was asked to evaluate various design alternatives for mixing and aeration of the (2) 62’ and (1) 45’ diameter aerobic digester/sludge holding tanks included in the expansion and upgrade. The Engineer compared complete aeration systems with aeration / hydraulic mixing systems with various combinations of hydraulics and aeration rates. After reaching a decision on his final design, the mixing system manufacturer completed a final design layout after analyzing placement of the diffuser grids relation to the hydraulic flows required. The final design is now in operation with lower than anticipated operating costs which have resulted in substantial yearly savings along with other significant advantages that will be discussed in this paper.