Perca’s DrilO2 system employs earthworms for wastewater treatment

Perca, Inc., an environmental technology firm, has developed an innovative system for water regeneration that uses earthworms and microbial communities to clean wastewater naturally.

"Nature has been cleaning water since the beginning of time," explains Russ Davis, Perca's President and CEO. "We have simply created a scalable way to focus and optimize those natural processes using vermiculture, biology and sustainable principles. What's exciting to us is how effective, robust and economical the system is - even for contaminants that are notoriously difficult to remove." Perca's proprietary vermifiltration design mimics natural processes to remove pollutants from wastewater and stormwater including BOD, TSS, nitrogen and phosphorus as well as certain metals and toxic chemicals such as PCBs (polychlorinated biphenyls) and deicers.

Davis noted that their technology has consistently achieved reductions of over 95% for some particularly challenging pollutants, while research into removing other contaminants continues at Perca's state-of-the-art Vermi-Tech Innovation Center (VIC).

Proven results in Walla Walla, WA

Two projects in Walla Walla, WA have highlighted the worms' capabilities and potential – one in collaboration with the City of Walla Walla, and the other as a pilot with the Washington State Penitentiary. Leah Rohan, Environmental Engineer with the City of Walla Walla, confirms the efficacy of the system. "We had a significant wastewater generator that had been struggling with compliance on some difficult constituents and as a result, had been out of compliance for some time. The solution that finally got them back into full compliance was the worm bed."

The City of Walla Walla's largest wastewater discharger is the Washington State Penitentiary. Not long ago, the Penitentiary was made aware that its wastewater contained some potentially toxic chemicals. "Our numbers were - and still are - fairly low, but we don't want to find ourselves out of compliance," says Dean Smith, Environmental Specialist with the Washington State Department of Corrections. "We had heard about Perca's system and decided to run a trial." According to Smith, after a three-month trial the worms delivered the results as promised. "It really is surprising that something so natural and uncomplicated can work so well." Perca has provided the WA DOC with a proposal for a full-scale system and the parties expect to talk more in 2025.

A scalable, natural solution for water treatment 

Industry experts are taking note of the eco-friendly system's success and potential. Carissa Yaremchuk, a Perca Board member and advisor, is the National Conveyance Solutions Director for Black & Veatch - a multinational engineering firm. "When I originally heard about the 'worm project' in Walla Walla it piqued my curiosity. The people I spoke with at the City said it was working as promised, so I contacted Russ and the Perca team to learn more. With these kinds of sustained results, I think we are going to see a lot more integration of worm beds in wastewater treatment across the industry."

"Chemicals like PCBs, PFAS (polyfluoroalkyl substances) and 6PPD-q (a tire preservative) are known toxic chemicals that can bioaccumulate in humans and animal tissue," continues Davis. "We know that if we can remove these chemicals where they are concentrated – frequently in wastewater and stormwater – we can keep them from finding their way into the food chain via streams, rivers and groundwater."

Perca's vermifiltration system is scalable, making it suitable for a range of applications, from larger municipal and industrial wastewater treatment to smaller-scale operations.

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