The Midwest Biosolids Association (MBA) hosted its first annual conference on March 26th at Purdue University in West Lafayette, Indianna. Purdue’s Beck Center, a huge agricultural research center surrounded by farms, was filled with about 165 people in attendance at this inaugural event – including NEBRA’s Executive Director Janine Burke-Wells. Professor Linda Lee, PhD, with Purdue’s Department of Agronomy, served as host for both the MBA conference and a Water Research Foundation project stakeholders meeting on the previous day. MBA also organized an excellent tour at the Merrell Bros offices in Kokomo, IN, featuring their recently patented biosolids dryer and a new collaboration with 374Water for PFAS destruction technology.
WRF Research Meeting
Before the conference officially kicked off, there was a WRF meeting on March 25th which covered two WRF research projects related to biosolids, with half-day updates on each. In the morning, it was the Stakeholder Collaboration and Engagement Workshop for the U.S. Environmental Protection Agency’s grant to WRF under its National Priorities: Evaluation of Pollutants in Biosolids Grants | US EPA -- or WRF’s Project #5125, Unregulated Organic Chemicals in Biosolids: Prioritization, Fate and Risk Evaluation for Land Application | The Water Research Foundation (waterrf.org). Following an update on the project, there were breakout sessions covering compound prioritization, informing solutions, and engagement and communication. In the afternoon, it was all about WRF Project # 5170, State of the Science and Regulatory Acceptability for PFAS Residual Management Options | The Water Research Foundation (waterrf.org).
MBA One Day Conference
MBA Vice President John W. Norton Jr., PhD, PE, with the Great Lakes Water Authority, was the MBA conference chair. The March 26th program was packed with presentations and panel discussions around four main themes: MBA organizational updates and activities; utility biosolids projects and programs; research efforts; and presentations by various consultants on state-of-the-art practices for managing biosolids. Of particular interest were presentations by Nick Basta, professor at Ohio State University, on using “hydrosolids” (drinking water residuals) to improve urban soils and, in particular, reduce lead concentrations. Stephanie Spalding with HDR reviewed the phased Master Plan for the City of Raleigh Public Utility Department for post-processing upgrades to enhance biosolids program resiliency and manage risk.
Another important presentation was by Dante Fiorino (Brown & Caldwell) with Stacia Eckenwiler (City of Columbus) about what is believed to be the first multi-sensor fugitive methane study in the Western Hemisphere! The project looked at methane emissions from the Columbus wastewater treatment facility, which uses anaerobic digestion, and led to a plan with solutions to reduce the fugitive methane leaks they found by over 90%.
Merrell Bros and SCWO Pilot Tour
On the last day of the trip, March 27th, the events coordinators lined up a tour of the Super Critical Water Oxidation AirSCWO [Technology - 374Water] unit being constructed by NEBRA member 374Water at the Merrell Bros. facility in Kokomo, Indiana. This is the unit which will be getting shipped to Orange County Sanitation District in California to start a pilot operation there very soon. The results of that pilot are scheduled to be presented at a Lunch & Learn webinar on October 25th with NEBRA member Hazen & Sawyer, a consultant on the project.
The tour was hosted by Merrell Bros. at its huge facility in the middle of a farm in Kokomo. The facility is an inventor’s paradise and seems like a great place to work. The tour group started in the employee classroom/breakroom, where lockers for each employee took up two entire walls. The group heard presentations by Merrell Bros. and 374Water.
Terry Merrell has recently obtained a patent for a double drum drying system that he explained prior to heading out to see it in action on the factory floor. The dryer uses “impulse” drying and flash evaporation in a continuous batch system which is very energy efficient. Terry made it his mission to reuse every bit and every type of energy within the system. Merrell estimates 0.5 to 0.65 kW per kg of biosolids is required (~910 BTUs per pound).
The Merrell dryer produces a flaky product (sort of like fish food) that is scraped off the drums and put through a pelletizer, again a Merrell design to produce pellets of various sizes for various end uses. Merrell is using it to make “designer fertilizers”, including spiking the pellets with potash, urea, lime, and even what they called “reverse polymers” that can capture moisture and release it into the soil.
Merrell has been experimenting with a foam fractionation process on low solids content sludges ~1% total suspended solids and looking for solutions for PFAS contaminated materials. Merrell realizes their dryer doesn’t deal with PFAS which is why Merrell Bros has teamed up with 374Water to treat the materials that are high in PFAS.
The AirSCWO pilot was still under construction, so it was not in operation during the tour. However, it afforded an opportunity to look inside the big Conex box that contains the process equipment. The end products are clean water and what 374Water calls “minerals” -- not ash – which is high in phosphorus (P2O5) and perhaps heavy metals. Analyses are ongoing. The pilot in Orange County will help answer some of the questions posed by the group about this new process.
The three-day event was a very positive experience for all. NEBRA’s Burke-Wells said “This conference was fantastic. It is amazing how far the Midwest Biosolids Association has come in such a short time and most of all to put on such a wonderful conference. The speaker line and the presentations were excellent. This was a memorable experience.”