Beyond Removal: Hydrothermal Alkaline Treatment for PFAS Destruction in Concentrated Wastewater by Somnath Mukherjee, Aquagga
Somnath Mukherjee, Staff Controls Engineer for Aquagga, showcased a hydrothermal alkaline treatment (HALT) proven to remove up to 99-99.3% of PFAS in water. He began by sharing that PFAS exposure causes cancer, liver disease, compromises immune systems, and that 97% of Americans have the chemical in their blood. Wastewater from industrial facilities and municipalities can contain high concentrations of PFAS that are difficult to address using conventional treatment approaches. However, using HALT, Aquagga is able to destroy the full suite of PFAS compounds in a range of complex liquid chemistries and has been validated in use cases across more than a dozen field demonstrations. It operates at subcritical temperatures (300-370 degrees celcius) and leverages pressure and pH to permanently destroy PFAS and achieve complete fluorine mineralization. Remaining water can then be sent to a wastewater treatment plant to make it drinkable. Looking ahead, Aquagga will continue bench testing work for pharmaceutical, semiconductor, landfill, and fluorochemical applications.
Jeff Dermond, Ecology, Office of Columbia River. Photo credit: Tom Ring
New Developments in Aquifer Storage and Recovery: Chasing the Yakima Basin’s “Sixth Reservoir” with Groundwater Storage by Jeff Dermond, Washington State Department of Ecology
Jeff Dermond, Hydrogeologist and Project Manager at Ecology’s Office of Columbia River, started his talk with an orientation of the five reservoirs in the Yakima River Basin which covers over 6,100 square miles and supports a $4.5 billion agricultural economy. All five hold a total of about 1.1 million acre feet of water. However, the key to the basin’s success is the “sixth reservoir”, snowpack, which can hold 2.4 million acre feet of water. Dermond acknowledged that snowpack is highly vulnerable to climate change if there are dry or warm winters or spring heat waves which can initiate a rapid early melt rather than melting gradually which is increasingly becoming more rare. Drought has significantly limited the Yakima basin’s water supply in 12 of the last 36 years, and any carryover storage from past seasons is no longer a reliable insurance policy when irrigators need large volumes of water late in the year and municipalities need a dependable year round water supply. The state has a legal framework designed for the population, agricultural practices, and climate from nearly a century ago, and modern problems require creative and collaborative solutions. Dermond stressed that there’s a paradigm shift in water extraction from “take it when you need it” to “take it when you can get it and keep it until you need it”. Given the gravity of the situation, Aquifer Storage and Recovery remains the most effective method to capture water for the future in a new reality of unpredictability of rain and snowpack melt. He challenged the audience not to think about how we will fill aquifers but instead how and where we can capture and store water when it’s available.
Hydrogen Peroxide as a Chlorine Quenching Agent to Prevent Trihalomethane Formation During Aquifer Storage and Recovery by Julian Howe, Central Washington University
Julian Howe, an Environmental Geochemistry master’s student at Central Washington University, started his research with the question, “Would aquifer treatment with hydrogen peroxide reliably reduce the formation of trihalomethanes (THM) in chlorinated water during storage, and if so by how much?” Water quality criteria in Washington State require disinfection of recharge water, which can result in the formation of disinfection byproducts (DBPs), some of which can be toxic and carcinogenic. One group of DBPs of concern are THMs which form when organic matter interacts with the hypochlorite ion. It has been proposed that treating the recharge water with hydrogen peroxide before it is pumped into the ground can reduce the formation of THMs. His experiment measured the formation of chlorine over time and compared dose responses. He determined that laboratory experiments controlling Total Organic Carbon (TOC) concentration, chlorine dose, and hydrogen peroxide dose can help determine the efficacy of this proposed treatment as well as the optimal timing and dosage of hydrogen peroxide.
John Langdon, Solar Saves Farms (left) and Chad Higgins, Oregon State University (right). Photo credit: Tom Ring
How Agrivoltaics Saves Farms (and Water!) by John Langdon, Solar Saves Farms, and Chad Higgins, Oregon State University
John Langdon, Oregon farmer representing Solar Saves Farms, and Chad Higgins, associate professor at Oregon State University’s College of Agricultural Sciences, spoke on agrivoltaics, a resource management approach that is at the intersection of energy, water, and agricultural production. The concept involves the use of solar panels to create shade shelter and reduce the need for extra water when crops and livestock get overheated. A reduced light environment creates a more conducive growth environment for plants, and water demand can be reduced by up to 50%. By providing shade, farmers can reduce evapotranspiration, a plant’s natural cooling process, and any additional water provided by farmers to cool their crops or livestock. It was found that providing partial shade can also promote a longer growing time for clover and flowers for bee pollination. Additional benefits to agrivoltaics is that solar energy is captured to be utilized on the property or sold in the form of electricity. They also unveiled a photo of the first fully electric tractor by John Deere and the AWRA audience was the first to see it. The duo concluded with a promising tagline, “The future is bright in the shade!”
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