How Organics Membrane Filtration Tech is Changing Industrial Wastewater Treatment

Organics in wastewater is a problem on multiple levels. They are hard to filter out and tough on industrial equipment. Organic-laden water is expensive to haul and dispose of. Generators have to stay on top of tight nutrient discharge limits. And, all along, headlines cry out about a water crisis – namely a worsening depletion of clean water supplies, with industrial operations and agriculture among heavy-weight contributors. They consume hundreds of billions of gallons of water daily.

In answer, Boston-based ZwitterCo developed a membrane filtration technology to separate water and organic solids. Membrane filtration is nothing new, but the company touts its product as unique in that its very fine filter – with a pore size of 1 nanometer in diameter – traps solid compounds that would otherwise pass through, making it immune to fouling or clogging, while conventional filters foul, compromising flow and ultimately necessitating the need to change filters often.

As Jon Goodman, vice president of Commercial Development ZwitterCo explains it, the tech company’s membrane separates out fats, oils, grease, proteins, sugar, and starch, as well as solids in residue from anaerobic digestion and in leachate. Clean, separated water can be reused as can the recovered nutrients. And the filters continue performing as new with a simple cleaning process.

The young company is catching the attention of a range of industries. The main ones are food and beverage, bioprocessing plants that use a fermentation process, agriculture, and landfill operations. Since its roll out, ZwitterCo’s filter has been installed in about six commercial projects and in dozens of pilots.

The magic is in the material’s chemistry. The membrane is made from hydrophilic (“water-loving”) polymers, enabling water to pass through while repelling solids that otherwise would stick to the membrane’s surface. Organics simply wash off with water and a little mild chemical cleanser.

The agriculture application in particular is taking off and a deep focus area of ZwitterCo, driven largely by farmers’ growing interest in anaerobic digestion (AD) to manage manure while producing renewable natural gas from this waste. The filter is a key component in a larger wastewater treatment system, with the membrane used to concentrate the digestate remaining after the AD process.

The process reduces both volumes of digestate and costs to haul it by 50 percent, Goodman says. Farmers reap the assets of fertilizer made from the digestate and clean water to reuse in their agricultural practices. And it’s easier to store the materials—a necessary practice as farmers can spread only so much of the nutrient-dense fertilizer in their fields at a time.

Reuse is a big factor in each of the industries that are beginning to adopt the technology.

“Wastewater reuse is an ESG goal, or even a license to operate. Not only is wastewater reuse good for the environment, it’s good for business,” Goodman says.

He sees a void that the wastewater-recycling technology could help fill in the western U.S. in particular, a region hit hard by droughts, especially California, a major U.S. produce grower dependent on very large water supplies.

ZwitterCo offers a “pay for performance” monthly model based on the filtration capacity needed to meet throughput requirements.

“Our customers prefer this model as it provides a measurable return on investment. It simplifies budget management, and it aligns incentives between all parties,” Goodman says.

Having landed $33 million in series A funding late in 2022, ZwitterCo has total fundraising to-date of $46 million.

In 2019 the startup was awarded a $1.25 million grant from the U.S. Department of Energy (DOE). The focus of the grant is to accelerate the development and commercialization of treatment technologies to transform water produced by the energy sector in the Permian Basin to a recoverable resource.

“Through our work with the DOE, we demonstrated that our membranes enable economic beneficial reuse for gun-barrel separated water. Our novel superfiltration membranes removed oil and grease to non-detect levels and were ideal as a pretreatment to reverse osmosis (RO),” Goodman says.

The system is proving ideal as a precursor to RO in other applications too, including with leachate treatment.  Using the membrane in front of RO reduces leachate and, with that, cuts discharge to wastewater treatment plants while allowing equipment to operate at higher concentrations without fouling.

The filtration process is one part of a multistep water treatment process. As such, ZwitterCo partners with Digested Organics, a water and wastewater technology provider that builds whole systems to generate clean effluent and recover nutrients. The collaboration was ZwitterCo’s entrance into the agricultural wastewater space.

Digested Organics’ systems treat between 10,000 and 1,000,000-plus gallons of digestate a day, according to David Faber, the company’s senior vice president of sales.

“The ZwitterCo superfiltration process allows us to recover 70 to 95 percent of the feedwater as a translucent effluent. The superfiltration effluent is very clean, enabling only small, dissolved materials to pass through, like salts. It also has the value of allowing for other technologies to be incorporated downstream,” he says.

Looking to expand its portfolio, ZwitterCo has invested in a technology innovation center near Boston. The plan is to figure out how to develop new membranes with different properties to remove more constituents from water.  One goal is to tailor the pore size for specific separations in order to further control which constituents pass through and which are rejected.

“We continue to innovate our technology and processes across industrial wastewater treatment markets to ensure our customers and partners have the tools, technology, and resources to reuse their wastewater efficiently. We have more on the horizon that we’re excited to share in the coming months,” Goodman says.