Sarasota civil engineer close to a biochar breakthrough in treating reclaimed water

Sarasota’s Steve Suau, a civil engineer whose specialty is watershed management planning and water resources, is enjoying the newfound interest the public has for his job.

Red tide has a way of piquing the public’s interest.

“People now actually are interested in nitrogen and phosphorous,” Suau said from his Progressive Water Resources office. “I never thought I would see the day. Since we have had red tide outbreaks, everyone is interested in nutrients.”

Increased interest or not, Suau has for years been investigating ways to produce cleaner waters in Florida. Now in partnership with Schroeder-Manatee Ranch, the University of Florida and the Southwest Florida Water Management District, Suau is about to embark on a pilot program that could have worldwide implications when it comes to cleaner waterways.

Although filtration systems using biochar (made from heating carbon-based materials such as wood, crop residue or animal manure in the absense of oxygen), sawdust and wood chips have been tested for years, Suau believes he has found a way to engineer biochar that would maximize its effectiveness to absorb contaminants.

His process involves adding magnesium to the heating process, which seems to increase the ability of the biochar to adhere to nutrients. He has a patent pending in partnership with the University of Florida on the process.

The goal is to reduce the nutrient load released into a watershed.

“There was a great opportunity here to cost-share a project with Lakewood Ranch,” said Jay Hoecker, the water supply manager for the Southwest Florida Water Management District. “We are looking into many opportunities to study this type of material that potentially can affect stormwater systems and advanced septic systems. Definitely, we want a better understanding of this. We are in this for the science aspect and to understand what opportunities we have.”

The Southwest Florida Water Management District is splitting the cost of the project with SMR, about $600,000 each.

Brent White, a senior water supply analyst with the Southwest Florida Water Management District, said the beauty of Suau’s engineering is that it is effective without the need for expensive capital improvement treatments.

“And this was a unique situation with Lakewood Ranch,” White said. “They are smack in the Evers Watershed, and because of their issues, they have no potable water irrigation, so they were looking for alternatives.”

SMR started Braden River Utilities shortly after it began developing 25 years ago to handle irrigation needs. The shift to bringing reclaimed water from the city of Sarasota, the city of Bradenton and Manatee County started in 2012 and continued through the middle of the decade. Lakewood Ranch now gets 100 million gallons a month from those sources.

Both the city of Sarasota and the city of Bradenton send reclaimed water to Lakewood Ranch that meets state guidelines for Advanced Wastewater Treatment standards (3 milligrams or less per liter of nitrogen). That water can be used within the Evers Watershed.

The Manatee County water does not meet AWT standards and therefore can’t be used within the Evers Watershed. Instead, it is used for agriculture outside the watershed.

The pilot program will treat 1million to 1.5 million gallons of the 8 million gallons of reclaimed water a day delivered from Manatee County. The site will be a 2 1/2-acre parcel along White Eagle Boulevard and Old Pope Road in Lakewood Ranch. It is a triangle-shaped property with a pump station located just off White Eagle Boulevard.

Water will be pumped into a basin that will be dug on the parcel and then it will seep through wood chip and sawdust filters, then biochar, before exiting into a holding lake just to the north. The process should take six to eight hours. The hope is that the water, once released from the basin, will meet the state’s Advanced Wastewater Treatment standards.

SMR, at its own expense, tested Suau’s process the past two years in 55-gallon drums with success.

“What we are doing now has a lot of implications,” LWR Development President Bob Simons said. “The Evers Reservoir, of course, is drinking water. We can’t use any [Manatee County reclaimed water] south of 44th Avenue and north of University Parkway because it doesn’t meet [AWT] standards.”

The project will purchase biochar pellets, which will need to be replaced annually, from a company in Gainesville. The wood chips and sawdust have an anticipated project lifespan of 30 years.

David Mazyck, a University of Florida professor of environmental engineering, said Suau’s work could lead to an inexpensive, engineered treatment that could be reproduced anywhere in the world and could give communities more control over their water quality.

“We are relying primarily on biochar, which is derived typically from waste products ... anything wood-based [and heated in the absence of oxygen]," Mazyck said. “From our perspective, we are dealing with a major environmental problem. First and foremost, we are coming up with a good engineered solution that can benefit Florida. There are hundreds of wastewater treatment plants in the state.”

Mazyck said more research is needed because biochar comes from natural material with a wide variance of inconsistent properties.

“It is very primitive in the way it is produced,” he said. “But within a year, we will know a lot.”

Simons said he expects to break ground on the project just after Jan. 1.

“To me, this is extremely exciting,” Mazyck said. “Out there in Lakewood Ranch, it’s a real system that changes every day. And we are dealing with a massive problem that’s not just a Florida problem. Then you have got Steve, who has been doing this for his entire career on an everyday basis.

“This is Steve’s idea, and my background is in carbon science. It took us 10 seconds to get on the same page. Steve is a high-energy, bright guy who had a vision about how to solve this. My PhD students will conduct the research and do the lab work. It’s like a jigsaw puzzle, and Steve was looking for a piece.”