BioMix System Provides Savings and Environmental Benefits for WWTF

The Town of Exeter recently constructed a new wastewater treatment facility to replace an antiquated lagoon process. The new facility was designed to substantially reduce the nitrogen load to the nearby Squamscott River which flows north into a sensitive tidal estuary.

To meet the stringent seasonal total nitrogen limit of 5 mg/l, the new facility includes a four-stage, Bardenpho process for enhanced nitrogen removal. The process utilizes anoxic biological selectors to create conditions for bacteria to reduce total nitrogen.

EnviroMix’s BioMix Compressed Gas Mixing was selected for multiple applications: 1st Stage Anoxic, Anoxic Swing, Mixing Limited Aeration, 2nd Stage Anoxic, and Aerated Sludge Holding.

BioMix technology was selected for numerous reasons.

  • The BioMix system offered 20% lower energy consumption than hyperbolic mixers.
  • BioMix is seamlessly integrated into the mixed zones and sludge holding tanks, improving the design, reducing the cost, and increasing the performance of the aeration system.
  • The centralized compressor system produces the high pressure compressed air while the control system distributes that air optimally to mix multiple processes throughout the facility.

BioMix provides the Town of Exeter annual O&M savings of $25,000 and 20-year net present worth savings of over $535,000 versus hyperbolic mixers. Additionally, the nitrogen load discharged to the Squamscott River has been reduced by over 100 tons per year.

Read the full case study.