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Activated Sludge Treatment

The activated sludge process design is based on the Parkson Corporation Biolac® process. This process uses a low volumetric loading, typically in the range of 10 to 12 pounds of influent BOD per day per 1000 cubic feet of aeration basin volume. This light loading combined with a longer solids retention time than is normally used for an extended aeration process ensures that the process will operate in the endogenous respiration stage at all times. This results in a stable, easy to operate treatment system that will produce consistently high quality effluent. This system has proven effective and efficient. To further enhance operation and reduce energy use, the Wave Ox® variation of the Biolac® process is used.

Using this system, in-basin nitrification/dentification is achieved by controlling the amount of air supplied to each row of aeration diffusers. Motorized valves are operated by a programmable controller to alternately supply air to and shut off each row of aerators in sequence. This sequential operation creates alternate oxic and anoxic zones within the basin that promote complete nitrification and dentification. Use of this process results in an effluent that exceeds current and anticipated future effluent requirements for nitrogen while reducing energy consumption and eliminating the need for a chemical feed system to add supplemental alkalinity. Centrifugal blowers located in the Operations Building supply process air. These blowers also supply air for the aerobic digester and post aeration. Four blowers are installed and space is provided for two future units.