Use of Energy in Water and Wastewater Treatment Plants
The cost of energy is 10% of a typical local government’s operating budget and a good portion of this goes to the operation of water and wastewater treatment facilities because the pumps, motors, and other equipment have to operate 24 hours a day and 7 days a week. Energy efficiency is a very practical consideration.
Best Practices in Use of Energy in Water and Wastewater Treatment Plants
• Use automatic controls when possible to monitor and control the potable water processing system.
• Incorporate Best Practices in use of energy in all changes and additions to the potable water processing system.
• Utilize a computer model to determine changes in pipe size, pumping grades, system pressures, and use and location of booster pumps and storage facilities, and to determine where variable flow rates should be put into operation.
• Develop and implement a system-wide leak detection and repair program.
• Install, where possible, energy-efficient variable speed drives to control the flow rate from pumps.
• When using groundwater supplies, monitor well production and drawdown to determine if there are any major mechanical problems and if the well is becoming inefficient because of overuse. Use the well sequentially to keep from over pumping.
• Promote water conservation which also will have a profound effect on reducing the amount of wastewater which needs to be treated.
• Reduce lawn sprinkling and utilize where possible treated effluent from the sewage treatment plants. It is absolutely essential to keep both systems separate and not allow any cross-connections.
• Charge a premium for high-volume users and establish conservation programs in their facilities.
• Use variable frequency speed drives in wastewater facilities based on the load requirements at a given time when there are minimum, average, and peak flows.
• Establish operational flexibility with all equipment in order to store wastewater at high peak flows, including seasonal adjustments and during times of tourists visiting the area, and process it during times of low peak flows, especially during the night.
• Recover excess heat from wastewater and use it to produce in-house electricity.
• Especially in the northern part of the country, cover the basins to avoid heat loss and freezing during the colder weather.
• Evaluate the aeration system and determine if it is working at maximum efficiency and, if not, add additional compressed air as needed. Use variable speed devices in introducing the air supply.
• Determine if the aerobic digester will work better with a smaller blower that would control the airflow with a fine bubble diffuser.
• Determine if anaerobic digestion would be effective for biosolids, since aerobic digestion is very energy intensive.