Energy savings at public treatment plants: information for elected officials and their staff
Wastewater treatment plants are among the largest electricity users in local government, and aeration (supplying air to the tanks where bacteria clean the water) is usually the largest part of that use. Ekster & Associates' control systems reduce it with the equipment the plant already owns. The results below were measured or verified by parties other than Ekster & Associates.
Verified results at public agencies
Pomona Water Reclamation Plant, Los Angeles County Sanitation Districts. In a demonstration funded by a competitive U.S. Department of Energy grant, an upgrade of the aeration system reduced the energy used for aeration from 1,300 to 550 kWh per million gallons. More than 40% of this saving (308 kWh per million gallons) was attributed to the DO/Nmaster and SRTmaster control systems (U.S. Department of Energy final report, 2025). The project received the 2025 CASA Excellence in Innovation and Resiliency Award, awarded to the Los Angeles County Sanitation Districts and Carollo Engineers.
City of Chico, California. A 2018 control project built around DO/Nmaster, with the plant's existing blowers, saved 1,198,692 kWh of electricity a year, worth $168,051 a year at 2018 rates, verified by an independent engineering firm under a Pacific Gas and Electric (PG&E) energy efficiency program. PG&E paid the City an incentive of $121,208. The avoided emissions are about 234 metric tons of CO₂e a year.
Five questions to ask before approving an energy project at a treatment plant
- What is the measured baseline, and who measured it? Savings can only be judged against a stated baseline period.
- Who will measure the savings: the vendor, or an independent party? At Pomona the results were measured in a U.S. Department of Energy demonstration; at Chico they were verified under a utility program.
- Does the project require new equipment, or does it use what the plant already owns? Ekster & Associates sells no hardware; its control systems run on the plant's existing SCADA system and blowers.
- Do the plant's operators keep authority over the process? Operators can override Ekster & Associates' control systems at any time, and faulty instrument readings are not acted on.
- Which comparable public agencies can confirm the result? Plant staff at Pomona and Chico are available to speak with other utilities.
How public agencies pay for energy projects
Public agencies have used the following routes; eligibility depends on each state and program.
- Utility energy-efficiency incentives. At Chico, PG&E paid an incentive of $121,208 under its energy efficiency program.
- Clean Water State Revolving Funds. The Green Project Reserve of the Clean Water State Revolving Fund includes energy-efficiency projects at treatment plants.
- State energy office programs. Some state energy offices have funded energy upgrades at publicly owned wastewater plants.
- U.S. Department of Energy assessments. The Industrial Training and Assessment Centers offer no-cost energy assessments to eligible water and wastewater plants.
Information for a district or city
On request, Ekster & Associates prepares a one-page fact sheet for a named district or city: the publicly owned treatment plants it contains, verified results at comparable plants, and the funding routes that apply. Email info@srtcontrol.com.
Ekster & Associates does not contact elected officials or agency staff about a procurement while a solicitation is open, other than through the named procurement contact.