The efforts of an ongoing partnership between NHSaves and the New Hampshire Department of Environmental Services (NHDES) continue to pay off for wastewater treatment plants (WWTP) around New Hampshire.
WWTP owners and operators of facilities in Somersworth, Franklin (Winnipesaukee River Basin Program), Pittsfield, North Conway, Troy and Epping were all recognized for improving the energy efficiency of their facilities.
This is the fourth year of the partnership between NHSaves and NHDES, an effort that started with a grant from the US Department of Energy and will continue going forward using funding from both the Clean Water State Revolving Fund (CWSRF) and NHSaves. WWTPs are commonly the highest energy user for municipalities.
While energy-efficiency champions have been identified since the start of the program, this is the first year of the NHDES/NHSaves WWTP Energy Efficiency awards. The winners:
Most Energy Efficient (Based on Flow): Winnipesaukee River Basin Program (WRBP)/Franklin.
- WRBP’s energy use of 853 kilowatt-hour per million gallons of treated wastewater (kWh/MG treated), when compared to available national benchmarks for similarly sized activated sludge WWTPs (ranging from 1,200 to 2,400 kWh/MG treated), shows the staff at WRBP is doing a fantastic job with energy efficiency on a national level as well as within New Hampshire.
Most Energy Efficient (Based on Pollutant Loading): Somersworth
- Somersworth’s energy use of 0.62 kilowatt-hour per pound of biological oxygen demand removed (kWh/lb BOD Removed), when compared to available national benchmarks for similar-sized activated sludge WWTPs (ranging from 0.7 to 2.2 kWh/lb BOD Removed), shows the staff at the Somersworth WWTP is also doing great work with energy efficiency, especially when considering most of the equipment at the Somersworth WWTP is 30+ years old.
Most Improved (Based on Flow): Pittsfield
- 63% reduction in kWh/MG treated (2012-2018)
Most Improved (Based on Flow): North Conway Water Precinct
- 44% reduction in kWh/MG treated (2012-2018)
Most Improved (Based on Pollutant Loading): Troy
- 56% reduction in kWh/lb BOD removed (2015-2018)
Most Improved (Based on Pollutant Loading): Epping
- 48% reduction in kWh/lb BOD removed (2012-2018)
For wastewater treatment, energy use intensity is typically based on the volume of flow treated by a WWTP in million gallons per day (MGD) or the strength or pollutant loading of the wastewater measured in pounds of biological oxygen demand (lbs BOD). The driving factor, flow or waste loading, for each WWTP varies. BOD is the amount of dissolved oxygen used by microorganisms in the biological process of metabolizing organic matter in water. As the pollutant loading in wastewater increases, the BOD increases accordingly.
Over the past four years, the program has:
- Benchmarked the electric energy use of 66 municipally-owned WWTPs.
- Conducted nine educational workshops for wastewater and drinking water system owners, operators, managers and engineers.
- Performed 30 comprehensive energy audits of selected WWTPs.
- Performed 11 comprehensive energy audits of selected drinking water facilities (DWFs) using set aside funds from the Drinking Water State Revolving Fund (DWSRF).
The WWTP energy audits have identified $5.5 million worth of projects that are estimated to save approximately $1.5 million annually in energy costs. Moving forward the program will use available NHSaves incentive programs and CWSRF principal forgiveness to encourage the implementation of these projects.