Here in our islands, fresh water is a precious resource. Water distribution and treatment and wastewater collection, conveyance and treatment account for over 3% of Hawaii’s total energy consumption. In 2013, over 290 million kWh/year were used in these processes at a cost of more than $95 million dollars. It’s estimated that 10-20% energy savings can be achieved through energy efficiency. With the potential for savings of this magnitude, water and wastewater sectors represent one of the single largest savings opportunities in the state.
Our water distribution infrastructure is old and requires much maintenance. For the water and wastewater sector, while public health and safety is always the number one priority, pumping and treatment efficiency may not be at the forefront of daily activities. Hawai‘i Energy can assist your water or wastewater facility with energy-saving projects that can improve your systems without compromising public health and safety.
Common Equipment Upgrades
- Interior and exterior LED lighting
- UV Disinfection
- Membrane bioreactors
- Biotowers and trickling filters
- Custom projects*
*Consult with an Energy Advisor today to see if your project qualifies for a rebate.
Schofield Barracks Wastewater Plant
Transformer, Electric Load Distribution Network, Membrane Bioreactors, Blowers, and UV Disinfection Upgrades
Annual Energy Savings: 971,342
Annual Bill Savings: $136,987
County of Hawai‘i Hilo Wastewater Treatment Plant
Pump Replacement with VFD and O2 Sensors
Annual Energy Savings: 246,891 kWh
Annual Bill Savings: $48,035
City & County of Honolulu Honouliuli Wastewater Treatment Plant
Annual Energy Savings: 287,781 kWh
Annual Bill Savings: $48,752
- Water & Wastewater Energy Management Best Practices Handbook
- Wastewater Facility Energy Checklist
- Drinking Water Treatment Facility Energy Checklist
- Evaluation of Energy Conservation Measure for Wastewater Treatment Facilities - EPA
- Energy Efficiency in Water and Wastewater Facilities: A Guide to Developing and Implementing Greenhouse Gas Reduction Programs - EPA
Tips for Water & Wastewater Treatment Facilities
- Monitor for even air delivery to aeration tanks and the distribution within the tank. Repair systems immediately if needed.
- Review your aeration tanks to assess if one can be idled.
- Install variable speed drives to operate the blower at an appropriate speed.
- Consider upgrading to a high-speed turbo blower for maximum efficiency.
- Check the sheave sizes on the motor and blower to identify the speed of the unit to identify if the speed can be reduced.
- Check discharge pressure of your blower to assess if the diffusers are dirty or a valve is partially closed.
- Check if any valves are closed or throttled on the discharge. Obtain kW readings and flow measurements on pump motor to identify its efficiency.
- Obtain power bills to check if there have been any noticeable changes.
- Note if any pumps are exhibiting excessive vibration during operation.
- Identify the pump you have had the most problems with and assess if a change in pump selection would resolve the problem, generally most pumps are oversized for their application.
- Review the load factor and length of time a pump is operating to assess if a smaller pump would help or a variable speed drive.
- Check that all appurtenances in the force main are properly working (such as a pressure release valve is functioning and not air binding the pump).
- Turn lights off when you leave an area and use natural lighting whenever possible.
- Use timers and occupancy sensors and keep them properly set (e.g. no outside lights during the day).
- Replace existing lights with newer, more energy-efficient LEDs, CFLs or T-8 lamps.
- Utilize day lighting in building renovations.
- Shade windows that are receiving direct sun.
- Make sure all exterior walls, ceilings and wall cavities are properly insulated.
- Keep doors and windows closed when running your air conditioning system.
- Consider applying ENERGY STAR® “cool roof” material to your roof.
- Install an Energy Management System (EMS) to control cooling systems.
- Choose ENERGY STAR® equipment when replacing cooling systems.