By Peter Chawaga
While consumers are still coming around to the idea of drinking recycled water, there have been far fewer ideological obstacles standing in the way of water reuse for non-potable purposes. A more open mindset from farmers about where their water comes from has meant that some of the greatest technological gains in reuse are being made in the agricultural industry.
To that end, reuse advocates the WaterReuse Association and Water Environment & Reuse Foundation (WE&RF) have teamed with Pentair, an industrial company with a water technology division, to highlight new ways that water recycling can be utilized to improve agricultural practices.
“Our three organizations are in a unique position to make farmers, lawmakers, and the public aware of the value of water and reuse in agriculture,” said Melissa Meeker, executive director of WateReuse and chief executive officer of WE&RF. “Pentair and WE&RF partner on research projects designed to help advance sustainable agricultural practices and the WateReuse Association uses the research to advocate for laws, policy, and funding to support this effort.”
The partners released an online video highlighting two projects utilizing sustainable agricultural practices, where the system for food production is based on local conditions and will last over the long term.
The first project, a St. Paul, MN, aquaponics facility, utilizes a “recirculating aquaculture system” designed and installed by Pentair along with Urban Organics. It’s an 8,500 square-foot, closed-loop, recirculating fish farm compromised of four 3,500 gallon tanks supporting 4,000 tilapia. It uses just 2 percent of the water required by conventional farming.
The technology behind the fish farm includes biological filtration for removing fish waste and redirecting it as plant fertilizer; solids removal and mechanical filtration; automated feed controls; water quality monitoring with integrated alarms and backup systems; water movement with energy-efficient pumps; and a purging tank that imparts the fish with a salt solution before going to market.
Pentair sees an avenue for this technology to be put to use for general wastewater reuse projects.
“In general, the water treatment process for aquaculture is comprised of many of the technologies used in the treatment of wastewater for reuse applications,” said Dr. Phil Rolchigo, Pentair’s vice president of technology. “Depending upon the end-use of the treated water however, the purity standards vary and often require additional advanced filtration steps.”
Additional steps would include coarse filtration, biological treatment to eliminate the organic matter, ultrafiltration to remove suspended solids and bacteria, and then UV disinfection, said Rolchigo.
The second undertaking highlighted in the video is the largest agricultural reuse irrigation project in the country, located in Monterey, CA. There, the Monterey Regional Water Pollution Control Agency operates a recycled water facility utilizing a flocculation basin, tertiary filters, and chlorine contact basins and uses it to distribute water to 12,000 acres of local farmland.
“The Monterey project is a roadmap for how utilities can partner with farmers or other industries to provide a sustainable water supply,” said Meeker.
By presenting these projects in an outreach video, the partners hope that others will be inspired to think about how cutting-edge technology can make their operations more efficient, effective, and sustainable.
“A video is a great way for people to see the technology and results of a project in action,” said Rolchigo. “Our hope is that it will serve as a springboard for people to then look to learn more about how they might be able to incorporate water reuse technologies into their own operations, whether it be in agriculture, industry, or a municipality.”
With 70 percent of the world’s freshwater supplies going towards farming, agriculture was a good place to start. When asked to project the state of agriculture and water use in next 50 years, Meeker is optimistic that a difference is being made.
“Innovative water reuse programs will become the norm as part of an overall integrated approach to sustainability in farming,” she forecasted. “Technologies that speed up the processes that already happen in nature can help us make sure that the next generations have a reliable and safe food supply.”