Energy Audits and Efficiency

Upgrades to the Neuse River WWTP included an aeration capacity nearly three times that of the existing system and resulted in a 20% annual savings in energy costs.

Energy consumed by process in a sample wastewater treatment plant - often aeration provides the best opportunity for improved efficiency.

Our design for the Town of Jupiter Nanofiltration Plant reduced energy consumption through a unique process design that utilizes pressure vessels with mid-span concentrate ports.

The LEED certified Bradley Avenue Water Treatment Plant includes variable speed pump drives that optimize operational control.

Energy efficiency improvements in progress for Johnston County include aeration efficiency improvements for the biological treatment system at the Johnston County WWTP, control strategy modifications at the filter influent pump station and denitrification filters, and variable frequency drives, power monitoring, and stand-by power generation capabilities at both water and wastewater treatment facilities and conveyance systems.

As energy costs continue to rise and more emphasis is placed on energy independence, energy security, and greenhouse gas reduction, efforts to reduce our energy consumption will continue to grow in importance. Water and wastewater systems are significant energy consumers, and owners of these facilities are continually seeking ways to reduce energy consumption and associated costs. Technology improvements, improved automation, and process optimization generally afford significant opportunities for energy savings. In addition, the recovery and the beneficial use of wasted energy sources such as biogas, fats-oils-and-grease (FOG), and waste heat also represent significant opportunities for reducing net energy consumption.

At Hazen and Sawyer, we closely monitor the most current technologies and new processes as they are introduced to the market, and conduct detailed evaluations to understand the ways in which these technologies can be applied to reduce energy costs. In addition, we are continuously expanding our energy auditing and management services to identify opportunities for reducing water and wastewater system energy consumption and to provide energy usage guidance to our clients.

These energy services involve in depth analysis and audits of a facility’s energy usage profile, treatment process and capacity, energy procurement rates, electrical and control systems, building envelope, and equipment condition to identify energy saving opportunities. By combining our water and wastewater system design and energy management experience, we are able to identify energy saving opportunities that are specifically beneficial to the water and wastewater industry. The following are just a few examples of our energy related experience in the water and wastewater industry:

  • Our experience has shown that aeration systems in wastewater treatment plants typically consume more energy than other processes. Hazen and Sawyer has long been a leader in the application of state of the art aeration system technologies, and we have designed many new or replacement systems that have achieved substantial reductions in energy costs. For example, we found using the recently introduced high speed blower technology can save significant amounts of energy especially in conjunction with combined pressure, flow, and dissolved oxygen control philosophies. We also design energy efficient pumping systems by using variable speed pumps and by optimizing pump impellers for better performance.
  • Process automation also plays a significant role in optimizing energy efficiency for water and wastewater systems. Integrating state-of-the-art automation and control systems and computerized maintenance and asset management systems enables our clients to optimize their energy efficiency by optimizing plant control strategies, track and analyze detailed energy usage data, and improve system diagnostics. For example, automated control systems can be used to manage electrical loads and reduce demand charges by detecting an impending peak and shifting non-essential loads to off peak periods. The payoffs of such efforts can be significant.
  • Another means for reducing net energy consumption involves the use of alternative energy sources, such as geothermal, solar, wind, biogas, and waste heat recovery. Using these alternative energy sources can benefit our clients by offsetting purchased utility power and generating renewable energy credits (RECs). Hazen and Sawyer has extensive experience in evaluating and designing biogas fueled combined heat and power generation systems. Utilizing biogas generated from the anaerobic digestion process to generate electric and thermal energy has resulted in significant reductions in purchased power for many of our clients.

By providing energy management and auditing services coupled with our extensive experience in water and wastewater system design, Hazen and Sawyer is able to provide our clients with optimum energy efficiency solutions and guidance to optimize their energy efficiency and significantly reduce operating costs.

For inquiries contact:
Bryan Lisk, PE, at blisk@hazendandsawyer.com