Energy Recovery

The Gwinnett County Department of Water Resources recently completed construction of Gas-to-Energy and Fats, Oils, and Grease/High-Strength Waste Receiving Facilities that will reduce energy costs as much as 40% at the F. Wayne Hill Water Resources Center.

The addition of a new CHP system and electric blowers decoupled the aeration process and digester heating demands at the Moores Creek WWTP, significantly improving operational flexibility, nutrient removal and utilization of the plant's digester gas.

Facing a steep increase in energy costs, Johannesburg Water is upgrading the sludge handling and digestion facilities at its five wastewater treatment plants. The new high-performance digestion facilities will significantly offset energy costs at the plants – as much as 55% at one plant.

The 16-mgd James A. Loughlin, Jr., WWTP can turn digester gas into electrical energy at a profit - creating $2.40 of present value with each dollar of invested capital – while simultaneously reducing greenhouse gases by tapping a readily available renewable energy resource.

Hazen and Sawyer provided engineering and design services and negotiated a net metering agreement with the local utility to maximize the benefits of the new CHP system at the Roanoke Regional WPCP.

The University of Connecticut now uses highly-treated wastewater effluent as boiler feedwater and makeup for cooling towers and chillers in its Central Utilities Plant.

The City of Durham was able to negotiate an agreement with a LFG-to-energy developer which results in annual revenue, including offsets for operation of the LFG system, of approximately $184,000 per year without any capital investment into infrastructure for the LFG beneficial use system.

At Hazen and Sawyer, we strongly believe that significant economic and environmental benefits are available to most treatment plants through the use of treatment by-products for the generation of energy. We have helped many municipal wastewater treatment plants implement energy recovery technologies as a means of reducing operating costs, often finding that the long-term reduction outweighs the up-front capital investment.

We bring to the table technical expertise, novel tools, and a sound methodology for identifying, evaluating, designing, and implementing energy recovery technologies that best serve the technical, economical, regulatory, and operational concerns of our clients. These technologies include conventional applications like cogeneration using digester gas, as well as less common applications like fuel cells, biosolids gasification, and biodiesel production from fats, oils, and greases (FOG).

At the outset of each project, we involve experienced senior-level staff from all applicable disciplines, considering both economic and non-economic factors to determine the most attractive processes and technologies. Our assessment of the feasibility and cost-effectiveness of the various energy recovery alternatives encompasses operability, constructability, maintenance of a plant’s operations during construction, and long-term sustainability (typically through Lifecycle Analysis).

Because we tap the expertise of specialized architectural, structural, process, mechanical, electrical, and control & information engineers, each of whom bring unique experience and perspective, we can quickly find optimal solutions to address any future operating needs.

We realize that plant operators face mounting challenges with regards to energy consumption. Hazen and Sawyer has the expertise and novel tools to analyze each alternative and help you manage your operating and capital costs, without interrupting the operation of your facility.

For inquiries contact:
C. Michael Bullard, P.E., at