Reflecting on a Milestone by Looking to the Future of Energy Production in Wastewater Plants

As of this June, I have been with Dewberry for a full year as a senior project manager with our water service line. I wanted to take this opportunity to reflect on my anniversary with some thoughts on past innovations, and how I hope to expand our practice in the future.

My prediction involves something that Europe is already capitalizing on that the U.S. should adopt with more fervor: anaerobic digesters.

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Where We Have Excelled

Before I joined Dewberry in 2014, the Marlay-Taylor Water Reclamation Facility was completed for St. Mary's County Metropolitan Commission (MetCom) in St. Mary's County, Maryland. It won the PISCES Award from the U.S. Environmental Protection Agency (EPA) in 2011 for using the same kinds of innovative wastewater treatment that are now trending globally with hugely effective results. We helped add value to the facility by adding a co-generation system that allowed the county to take advantage of methane gas byproduct rather than wasting it – thus adding sustainable power during peak usage time periods and keeping energy costs down.

I know that this is just the beginning. Both the amount of methane gas that's currently being produced from wastewater and the number of water treatment plants that harness such energy can be improved upon. Currently, many wastewater treatment plants in the U.S. rely on aerobic digestion rather than the vastly superior anaerobic digestion process – a process that can produce more energy than it consumes, is nearly odorless, produces waste with no germs, and is 100 percent organically sustainable.

The difference between these two treatment concepts is that aerobic digestion pumps air into the reactor in order to process the waste whereas anaerobic digestion thrives without air. This is important because without oxygen, the waste can immediately convert wastewater into methane by a chemical process similar to fermentation. Besides saving time, keeping air out of the process can have a 70-80 percent energy reduction that would usually be diverted to large air blowers, which consume massive amounts of energy and are costly to maintain.

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Where We Can Improve

Today most U.S. wastewater treatment plants that utilize anaerobic digestion do so only for solids processing due to the fact that most incoming municipal and industrial wastewater is too diluted for anaerobic digestion. Consequently, the future possibilities of this sustainable energy reuse system involves more than just the process of plant mechanics, the method itself can be impacted as well and enhanced to be effective in creating bio-energy for a full cross-section of municipal and industrial wastes. For example, the incoming wastewater collected by traditional wastewater treatment facilities could be improved by doing what many U.S. farmers are already doing with their animal waste.

These innovative dairy farmers are blending diluted farm waste with table scraps from nearby school cafeterias, a concept called co-digestion, which is also very popular in European countries like Germany and France. By adding fats, sugars and other highly energetic waste to the feedstock already created during the wastewater treatment process, utilities can also improve their bio-diet and increase bio-energy production from 18-20 percent efficiencies to nearly 80-90 percent. Also, by partnering with nearby schools or other organizations with high energy waste, our energy production in wastewater anaerobic digestion facilities can and should become a more productive source of energy that benefits the entire community and the health of our environment, a win-win scenario.

I'm excited to build upon our experience as a leader in the wastewater industry to identify more opportunities to go outside the traditional water/wastewater processes to create more integrated sustainable practices.

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