National Energy Awareness Month is coming up in October, and here at Boxelder Sanitation District, we’re acutely aware of how wastewater treatment and energy usage are connected. Today, we’re sharing an overview of how energy is used in wastewater treatment, as well as what we’re doing to reduce energy usage.

Where is energy used in the wastewater treatment process?

Energy is used at almost every step of the wastewater treatment process. We use energy to move, filter and clean water so it's safe to discharge back into Boxelder Creek, and ultimately, the Poudre River. Most of the energy we use comes from electricity, which powers the pumps and machines needed for these tasks. A very small percentage of energy comes from natural gas, mostly used to operate our HVAC.

Some examples of where our treatment plant uses power are:

• Water Pumps: Water pumps are needed to move water through pipes from one location to another at the treatment plant.
• Aerators, Compressors & Blowers: Used for aeration, compressors and blowers add air to water during treatment to assist with the removal of wastes. The total aeration process makes up a significant part of the plant’s motor capacity.
• Screw Presses: Screw presses separate water from solids in the wastewater treatment process.
• Lighting: Our plant team has upgraded all light bulbs and panels to LED in an effort to reduce energy usage.

Because we use energy in so many facets of our operations, it’s essential that we are forward-thinking about how we can be energy efficient.

How Boxelder is Mindful of Energy Use and What We’re Doing to Reduce It

We’re always looking to reduce energy usage and improve energy efficiency. Improved energy efficiency is one of many main reasons we do capital improvements. When we can improve efficiency when we upgrade our equipment to meet new standards, it’s a win-win. Not only does technology improve over time, but also, each component in our process has a lifespan. As we mentioned in a recent blog, our District is over 50 years old, and replacing aging infrastructure is a vital part of maximizing the efficiency of our operations.

In addition to upgrades, we always make sure we’re using both new and old equipment efficiently by following best practices. When our equipment is well-maintained and operated according to best practices, it works at peak efficiency.

Several examples of how our 2024 and 2025 projects will improve energy efficiency are:

• Realigning and increasing the size of the bottlenecked lines will improve flow, requiring less energy to move wastewater through them.
• Combining two sewers in the District into one (the Old Clay Interceptor, OCI, and the Cooper Slough Interceptor, CSI) will ultimately require fewer resources and less energy.
• By exploring other methods for biosolid processing, we’re looking to reduce energy usage further and increase the efficiency for thickening solids for easier removal.

You can read more about these capital projects on our past blog. Mentioning them in this discussion of energy efficiency highlights how improvement processes don’t just update infrastructure but also make it more efficient.

CSU energy audit, findings & implementation

In addition to our own internal pulse on energy efficiency, in 2022, we had the pleasure of hosting a team of graduate and undergraduate students from Colorado State University (CSU). Their objective was to perform an Industrial Assessment Report in partnership with the CSU Department of Mechanical Engineering and the Industrial Assessment Center of the U.S. Department of Energy.

These students had the opportunity to inspect every square inch of our treatment plant, looking for ways to reduce energy usage. Their report was extensive and encompassed a wide range of suggestions that we were eager to put into action.

To begin, they reported that we were already using the following best practices to improve energy efficiency and reduce environmental impact:

• Use of recycled, treated wastewater for the sprinkler irrigation system on site.
• Use of high-efficiency motors throughout the plant.
• State-of-the-art administration building with LED lighting, occupancy sensors, smart thermostats and energy-efficient building envelope.
• Variable frequency drivers (VFDs) are installed on pumps that do not run continuously.
• Oxidation ditches alternate between anaerobic and aerobic operation, more efficiently removing nitrogen and simultaneously reducing energy consumption from aerators.
•  Aerators in oxidation ditches and aerobic digestors are controlled based on dissolved oxygen (DO) levels.

The report’s main recommendations were to:

• Install a photovoltaic (PV) solar array onsite to offset electricity usage.
• Reduce pressure set points on aeration equipment.
• Reduce heating set points in the solids building.
• Use of solar drying to produce Class A biosolids and avoid landfill costs.

Implementing their recommendations resulted in a significant reduction in energy use. The suggestions about reducing pressure set points and heating set points required no capital to implement. Following through with these two recommendations allowed for an overall savings in natural gas and in electrical demand charges for one of our most energy-intensive processes.

The team had additional recommendations that will prove valuable as we forecast future capital projects and reevaluate our facility’s energy efficiency and long-term goals.

Boxelder Sanitation District Cares About Our Energy Use

We are aware that we are a large energy user in our community and that operating a wastewater treatment plant requires thousands of kilowatts of energy. Because of this, we adhere to best practices in the water sanitation industry, carefully plan capital projects that increase efficiency and seek out recommendations for how we can improve—like we did with CSU.

While there is always room to grow, and new technology is constantly emerging, our Board of Directors and team do everything possible to reduce energy usage and operate efficiently.