We used to hate algae, but now it’s growing on us

Imagine H2O
Sep 27 · 4 min read

In the world of water and wastewater, algae is often seen as the problem.

With agricultural runoff, municipal and industrial wastewater, and other sources of nitrogen and phosphorus entering our waterways, harmful algal blooms are increasing at an alarming rate. This is contaminating our drinking water, killing marine life, and polluting the broader environment. In the US alone, harmful algal blooms cost the economy nearly $5 billion every year and threaten the drinking water of 48 million Americans.

But what if we flipped the script and instead saw algae as the solution? By using algae to treat wastewater inside the plant, you can prevent algae from growing unchecked outside the plant.

That’s exactly what Martin Gross sought to achieve when he started Gross-Wen Technologies (GWT). Treating wastewater with algae isn’t a new concept by any means, but GWT is the first to optimize it for municipal plants. Their patented revolving algae biofilm (RAB) technology makes the process more compact, productive, affordable, and sustainable than the status quo.

The RAB system consists of algae growing on vertically oriented conveyor belts. As wastewater is passed through the belt, the algae grows by “eating” the nitrogen and phosphorus from it. The algal biomass grows even more rapidly by taking carbon dioxide from the atmosphere.

  • Treated Wastewater: Nitrogen, phosphorus, and other pollutants are removed from the wastewater to prepare it for compliant discharge into the environment.
  • 100% Natural: This wastewater treatment process does not use any chemicals or require energy intensive aeration. In fact, for every 1 ton algae produced, 2 tons of carbon is sequestered from the atmosphere.
  • Waste to Nutrients: By capturing nitrogen and phosphorus from the waste stream, GWT repurposes it into valuable, nutrient rich fertilizer, bioplastics, and biofuels.

Given their unparalleled tech, we were thrilled to welcome GWT to the 2021 Accelerator cohort. Since joining, the team has made the most out of the program — actively participating in all webinars, presenting their technology to two key program sponsors, and engaging with 13 mentors (and counting) from our network.

When the GWT team was looking for an independent board member, we introduced them to Joe Zuback (President and CEO, Global Water Advisors). After an extensive process, they selected Joe as a result of his leadership in the wastewater treatment industry and his expertise around commercialization and project financing.

GWT has celebrated a number of milestones this year including growing their team, closing an oversubscribed $6.5M Series A, and announcing their first commercial deployment in Slater, Iowa.

“Imagine H2O has connected us to mentors with expertise in financing, technology development, and manufacturing. Their network and programming have been incredibly valuable to GWT as we continue to grow and refine our business model. Although we have learned several industry specific lessons the hard way over the past several years, we would be a full year further along if we went through this program when we launched in 2017.” — Martin Gross (CEO)

The deployment follows a successful demonstration project with Slater and a competitive bidding process, during which the GWT system was able to demonstrate over $1mm in savings to the city compared to alternative technologies. The project, which is currently under construction, will be fully operational in 2022 and will treat approximately 1 million gallons of wastewater per day and remove 150 tons of carbon dioxide from the atmosphere annually.

With a solid track record in place with municipal customers, GWT has started to explore other applications for its innovative technology, with a focus on dairy operations in 2022. Dairy farms are not known for their sustainability, but that could change with the RAB system, which is why GWT is the recipient of IH2O’s 2021 Accelerator Top Deployment Award. The award provides $20k of funding to help support a pilot deployment of the RAB system at one of the nation’s largest dairy operations in which the technology will be used to sustainably and cost-effectively recover nutrients from anaerobic digestion effluent all while reducing the farm’s carbon footprint. The project is planned for 2022 and at-scale will have the following annual impacts:

  • 270 tons of dried algae produced
  • 5,000 metric tons of CO2 avoided
  • ~$1M increase in revenue for the dairy farm

Even with all the recent progress, GWT is not slowing down. The company continues to actively build out their sales pipeline, explore new financing options for customers, and build out their team, particularly around marketing and communications. So if you are a potential customer, an engineering consulting firm, a project finance expert, or a strategic partner, get in touch!

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