Wastewater treatment facilities operate 24 hours a day, seven days a week, and are often one of the largest energy consumers in a community. In 2016, the Sanitary District of Michigan City completed an energy efficiency audit of their wastewater treatment plant and implemented several high-impact infrastructure upgrades. The facility achieved $40,000 in cost savings in the first year.
| Action | Applicable Resources |
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Encourage energy data transparency and create upgrade plan
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Use financial and structural incentives or mandates
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Upgrade city operations
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Energy efficiency improvements in wastewater treatment facilities save energy, generate cost savings, reduce emissions, and improve overall energy security in the community.
According to the USEPA, energy accounts for 25-40% of the total operating costs of wastewater plants which often rely primarily on electricity. Activated sludge systems are the most common facility type in the U.S.—this system involves aerating the waste and then introducing microorganisms that clump together after digesting the organic matter, allowing for their easy removal from the relatively clean liquid. The aeration of the sludge accounts for 50-60% of all electricity used in these systems due to the electrical power requirements of the pumps, blowers, and other equipment. The Sanitary District of Michigan City had long been considering updating its aeration infrastructure in order to make the operations more energy efficient and to reduce noise pollution in the work environment. With support from an energy audit by a state certified contractor, Michigan City was able to uncover important energy use data and identify five pathways for improving its energy efficiency.
In Indiana, municipal governments usually must follow specific procurement procedures for acquiring and installing new technologies. However, pursuant to the provisions of Indiana Code, Chapter 36-1-12.5 Guaranteed Savings Contracts process, governments can skip some of the procurement steps if the technology upgrade is guaranteed by a state certified energy savings contractor to pay for itself in 20 years or less.
Michigan City was able to use this savings guarantee to secure their preferred technology through Energy Systems Group (ESG), a contractor, rather than through the typical design, bid, and build process. ESG first completed a full investment-grade energy audit report for the Sanitary District in October 2016. Five strategies were recommended in the report: wastewater blower retrofit, LED lighting, motor control center replacement, chemical feed update, and an electrical capacitor upgrade. Michigan City decided to pursue two of the updates as a first step: blowers and lighting. Blowers are considered to be the lowest-hanging fruit because they are the most energy intensive equipment in the treatment process and new models are much more energy efficient than older equipment, and lighting is a relatively quick and easy upgrade. Working through ESG, a sub-contractor installed a much more efficient blower system. The team chose high efficiency Sulzer brand blowers.
The total blower and lighting project cost was $1.8M. Michigan City financed $1.6M of the cost through a five-year lease-purchase agreement with a local bank and the loan is being paid back with the savings and customers’ fees. In addition, Michigan City was able to receive a $240,000 rebate through the Northern Indiana Public Service Company (NIPSCO) based on the energy savings resulting from the project.
The project started in October 2016 and was operational by April 2018.
Prior to the upgrade, Michigan City was operating multiple blowers. With the new blowers, the plant only needs to run one blower at 60% capacity. Setting a minimum speed for the blowers has also improved performance. Since April 2018, the plant has observed a 10% reduction in overall electricity use and is on pace to see more than $40,000 in savings in the first year since the updates. The old blowers were also very loud when operating—the updates dramatically improved the work environment. The plant also saved money by reducing the amount of chemicals in its treatment feed.
In the coming year, the Sanitary District team plans to identify options to have all operations powered by solar energy and to initiate another energy audit of its plant by the University of Illinois-Chicago, which will be free through NIPSCO.
Lessons Learned
Michael Kuss, the project manager and General Manager for the Sanitary District, gave this advice:
“If you have the capacity, participate in organizations that help you voluntarily make improvements in your operations that do not pertain to a regulation or rule. For example, we are members of the Partners for Clean Air Program. Since joining, we have expanded our peer-learning network, and learned a number of ways we can work to clean our region’s air and improve our facility’s resilience.”
Michael Kuss
General Manager, Sanitary District of Michigan City
mkuss@mcsan.org
219-229-1298
There are many different ways to improve energy efficiency in your area. One common way is to convert to LED lights like Indianapolis, Indiana who converted their streetlights to LED lights.
