Problem Solved: Benton, Illinois

The City of Benton, Illinois is constructing a new wastewater treatment facility to replace the decades old plant to provide improved treatment to meet permitted requirements. The new facility is designed to treat 1.65 million gallons per day of wastewater using an oxidation ditch, which will provide nitrification and biological phosphorus removal EnviroMix’s BioCycle-D^TM Aerobic Digestion Process was selected to be an integral part of the plant design. Selection criteria for EnviroMix’s system included both energy efficiency and improved sludge digestion process control.

It is projected that the Benton Wastewater Treatment Tacility will experience 60% energy savings versus a conventional diffused aeration mixing system designed at the Ten State Standards volumetric airflow rate of 30 scfm per 1000 ft³ of tank volume. This equates to approximately $40,000 in annual energy cost savings!

De-Coupled Aeration from Mixing facilitates independent control over oxygen transfer and mixing, which can be applied either intermittently or concurrently.

BioCycle-D effectively de-couples aeration from mixing by right-sizing the diffused aeration system to satisfy process oxygen demand and applying energy efficient mixing through the use of the BioMix Compressed Gas Mixing System. BioCycle-D maximizes sludge destruction, minimizes energy consumption, and provides automatic process control through instrumentation feedback.

Unlike a conventional diffused aeration mixed aerobic sludge digestion process, whereby over aeration can result in uncontrolled nitrification, depletion of alkalinity and increased energy consumption, BioCycle-D controls and optimizes the digestion process. Controlling the aeration or aerobic phase of the process through dissolved oxygen instrumentation feedback results in optimized air delivery and effective digestion. Controlling the anoxic phase of the process through pH/ORP monitoring and efficiently mixing without air via BioMix, promotes denitrification and alkalinity recovery without excessive phosphorus release to the digester supernatant. The process benefits of optimized digestion also result in improved sludge characteristics.

BioCycle-D will be a key part in keeping Benton’s operational cost low and providing highly effective sludge treatment.