Case Study: Waste Water Treatment Plant

High Volume Low Pressure Turbo Compressors Decreases Energy Usage

Working though PG&E and the Ecova Air program, a relatively small wastewater treatment plant located in the city of Benicia, near San Francisco, was provided a substantial incentive for upgrading their compressor/blower system and essentially halving the amount of energy used by their aeration system.

Wastewater treatment facilities commonly use low-pressure multi-stage blower/compressors to supply air to aeration tanks where mixing and biological oxidation is promoted. These throttle controlled multistage blower/compressors are notoriously inefficient, may require independent cooling, and a great deal of maintenance while offering poor control, loud noise, and a large physical footprint.

Alternatively, there is a technology of a completely different design from these existing compressors. This centrifugal High-Volume, Low-Pressure (HVLP) turbo compressor uses precision machined components and integrated variable frequency drive controls that allow it to match the existing system flow and pressure requirements while using substantially less electricity.


This HVLP compressor technology can be used in multiple other industries and processes including:

  • Air knife applications
  • Oil free air supplies
  • Flue gas, oxidation air
  • Pneumatic conveying of powder, flour, chemical gas
  • Pulp and paper industry
  • Drying, processing, packaging
  • Fermentation
  • Many other custom processes

Although the cost for this new technology is higher than purchasing a replacement multistage compressor (or upgrading the existing compressor with a variable speed drive), kWh usage is dramatically reduced. Most importantly, after replacing the two operating compressors, the sustained energy savings combined with the one-time PG&E incentive resulted in a project payback of just over two years.*

After participating in the PG&E Ecova Air program, the City of Benicia received a total incentive of $65,520. The project was comprised of:

  • 3 qty. existing 125 hp aging multi-stage blower/compressors
  • Replaced by 3 qty. 75 hp HVLP turbo compressors (1 unit in stand-by mode)
  • Estimated energy savings (based on 2 qty compressors): 625,100 kWh per year
  • Savings are equivalent to removing 45 cars from Benicia’s roads and 33 residential homes from the electrical grid**
  • Incentive was 25% of the total project cost and 75% of the 3rd unit cost
  • Estimated energy cost savings: $54,772 per year

Download Case Study

*Each project will have individual results

**Carbon savings as defined by The Climate Registry