May 15, 2017

Tailwater Systems: Nitrate Remediation…in Your Backyard

Problems with nitrates in your wastewater or well water? Tailwater Systems has you covered. The agtech start-up company designs, builds and operates high-performance bioreactors for removing nitrates and other contaminants from field drainage and drinking water wells. The systems are compact and can be placed anywhere—in a field, next to a greenhouse or near a lift station.



The concept for Tailwater began in March 2014, when John Skardon was helping a fellow faculty member at California State University, Monterey Bay (CSUMB) to maintain a woodchip bioreactor to remove nitrates from surface runoff. When working on the project, one question continually popped up in Skardon’s mind: is this the most efficient and cost effective method for removing nitrates and other contaminants?

He decided to take action.

“I spoke to ag association representatives in the Monterey County and Central Valley area and learned that there was no workable solution for farmers or property owners to solve the nitrate problem,” said Skardon. “I wanted to find a low cost and simple technology that could be powered by solar panels and have the ability to reduce nitrate levels well below the state and federal limits.”

Skardon, a chemical engineer by training, knew that water treatment facilities around the world had been using biological remediation for nitrate and phosphorus for many years. However, all these existing remediation systems were incredibly large, treating hundreds of thousands to millions of gallons of water per day. He reasoned that if these systems could be downsized without loss of performance, the agricultural community might finally have a very competitive solution to the nitrate problem. Skardon noted that a 2010 report from UC Davis about treatment options for nitrate in drinking water clearly showed the economic advantages of a biological approach to treating these water contaminants. However, the report did not go into the details of the many types of biological treatment systems.

Skardon applied for and received a grant from the U.S. Environmental Protection Agency to work with students at CSUMB to develop a small scale bioreactor that can be located at the edge of a field so that farmers can treat the waste water before it leaves their property.

Working hand in hand with undergraduate students at CSUMB, including Hunter Burnham who played an integral role in the development, Skardon was successful in scaling down the systems to an extremely small footprint. “Not only did it work, but the denitrification rate was close to the rates achieved by industrial scale systems. Further, the systems required a very small footprint, produced no brine or waste and consumed a very modest amount of power,” noted Skardon.

Right then and there, in May 2016, Tailwater Systems was born.



Tailwater Systems recently completed the build of a fully functional bioreactor at a commercial greenhouse operation in Watsonville. At this particular greenhouse, the water flowing out of the irrigation well contained a nitrate level that was seven times higher than the allowable limit of 10 mg/L NO3-N.

“We plumbed the irrigation well into the bioreactor and started the system. The bioreactor reactor was sized to accommodate two hours of flow rate (called the residence time). The nitrate level was reduced by 92 percent to about 5ppm, or 50 percent below the legal limit,” said Skardon.

The bioreactor at the greenhouse can process five gallons per minute and fits into a 10 x 10 square foot area. The systems can be easily scaled from up to 50 gallons a minute.

With the engineering and technology perfected, Tailwater Systems can build a bioreactor on the grower’s site in four to eight hours. Limited site preparation is required and the system can be moved from site to site. The company provides monthly maintenance and servicing of the bioreactor.

The startup is looking to partner with farmers and property owners in the Salinas Valley and Central Valley to help tackle the nitrate issue. “We are taking away the pain growers have with trying to meet the nitrate standard. Our systems will do everything you need to meet county, state or federal requirements for nitrate,” said Skardon.



Beyond reducing nitrates in surface drainage, Tailwater Systems also works well with subsurface drainage, well water and treating other contaminants including phosphorus, sediment and iron. Additionally, they are attempting to solve the pesticide problem and are currently developing a proprietary approach to remove and destroy these chemicals using bioremediation techniques.

In an effort to build their network of relationships in the agriculture industry, the startup joined the Western Growers Center for Innovation & Technology in December 2016.

“We are so thankful for all the support we’ve received from the industry thus far,” said Skardon. “We hope that by being in the Western Growers Center we can continue to work together with growers in the Salinas and Fresno area to promote this system. We have a solution better than anyone else and are right here in your backyard!”

Tailwater Systems is among 36 start-up companies in the Center for Innovation & Technology looking to solve agricultures more pressing issues, such as water quality. For more information about Tailwater Systems’ compact denitrification systems for water purification, visit or contact John Skardon at [email protected] or (831) 204-8140.