What’s in Your Water?
Prime Movers Lab is delving into the latest breakthroughs in water treatment and meeting startups that are tackling the perils of PFAS and discovering not-so-hidden treasures in our water
Let’s start with the bad news, the one that has been lighting up headlines and EPA newsletters increasingly since 2021 — PFAS. PFAS, or (per- and polyfluoroalkyl substances) are a class of chemical compounds found in many household and industrial products as well as firefighting foams that are heavily used in aviation facilities. PFAS are known as “forever chemicals” which can be harmful to human health even at very low levels of exposure.
PFAS remediation technology can be broken into three steps: detection, concentration, and destruction. Testing for PFAS is challenging because it is measured in ppt (parts per trillion), which requires large, expensive scientific equipment, and founders have reported lead times from third-party laboratories of up to six months. There is a significant opportunity in real-time field testing and accelerated lab testing that can help stakeholders make informed decisions about PFAS. For example, the folks at Fred Sense have adapted their electrochemical field sensing hardware developed with biosensors for COVID-19 to help stakeholders identify PFAS plumes in groundwater.
Once PFAS has been detected, it needs to be disposed of or destroyed. When doing so, it is advantageous for the concentration to be as high as possible to keep disposal or destruction process liquid volumes low. The concentration unit operation has an existing commercial solution and is typically done using methods like foam fractionation and air floatation. Then, the concentrated PFAS residual is disposed of as hazardous waste or, ideally, fed to a PFAS destruction unit operation.
When evaluating PFAS destruction technologies, keep in mind that there are many different types of PFAS, and the molecules can vary significantly in size and shape. So you need to ask the question: “Which PFAS?” Some technologies are mass transfer limited, which means they rely on these molecules coming into contact with a reactor, a surface, or an air bubble and may struggle with capturing and destroying short-chain PFAS. Smaller chains are less hydrophobic and prefer to stay in the water plus there are fewer chances that the molecule will touch the surface, allowing the reaction to occur. This is one reason companies like Aquagga destroy the PFAS in a bulk hydrothermal alkaline process. Other technologies like Axine Water Technologies use innovative reactor configurations in their electrochemical oxidation process to tackle this challenge.
The winners in PFAS innovation destruction will be able to destroy a wide range of PFAS, not just those that are being regulated currently. The winners in detection will develop a real-time sensor with high sensitivity for a broad range of compounds.
Other emerging contaminants worth mentioning include active pharmaceutical ingredients (APIs) and microplastics. Look for our upcoming water treatment thought paper for insights on these and more.
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On to the good news! Unlike PFAS, which we’d like to find, remove, and destroy, there may be things in your water that you want to remove, separate, and sell for a profit. Although this is especially true if your water happens to be effluent from a manufacturing, agricultural, mining, or extraction operation the same can be true for domestic wastewater, to which we all contribute.
Resource recovery from wastewater has mostly focused on collecting nitrogen, phosphorus, and organic matter for reuse as agricultural fertilizer. As fertilizer prices surged after the invasion of Ukraine, increasing attention has been drawn to alternate sources of mined nutrients. Processes for this include precipitation of struvite (magnesium ammonium phosphate), ion exchange, membrane technologies, and absorption. There are also opportunities for biogas and other energy production from domestic wastewater.
However, nutrients from domestic wastewater are just the tip of the iceberg. Several major industrial sectors produce particularly high concentrations of big-ticket effluents. In food manufacturing, valuable polyphenols and hydroxytyrosol can be recovered from olive oil extraction processes, proteins and lipids from dairy industry wastewater can be recovered as feedstocks, and anti-nutritional factors (ANF) are contained in soybean wastewaters, which have potential therapeutic value for cancer treatment. Semiconductor wastewater contains tungsten, silicon, copper, aluminum and gold which can be reclaimed and reused in manufacturing. Wastewater from the pharmaceutical industry is rich with high-value products. Nanofiltration using membranes is an effective separation technique for high molecular weight pharmaceutical products (>250 Da).
With increasing stress on battery supply chains, attention has turned to wastewaters containing lithium from the extraction industry like oil and gas-produced water, geothermal brines, and mine tailings as potential new sources of these minerals. There are several players in the selective mineral extraction game and most of them benefit from a highly concentrated brine stream input. So, there is an opportunity for those who can produce highly concentrated brine like Eden Tech and for those who can perform selective separation for target minerals like lithium from magnesium.
But what is motivating the producers to make a change and think of water, and these resources, circularly instead of linearly and start investing in water treatment and extraction? For wastewater producers, these tantalizing opportunities for additional revenue streams may not be on their radar quite yet, but oftentimes wastewater disposal itself is a mission-critical cost that could drive the decision to improve water circularity. In the next decade, valorization of wastewater to reclaim valuable minerals will help drive the economic case for water recycling.
Prime Movers Lab invests in breakthrough scientific startups founded by Prime Movers, the inventors who transform billions of lives. We invest in seed-stage companies reinventing energy, transportation, infrastructure, manufacturing, human augmentation, and agriculture.
