ROBERTS -- Anticipation is beginning to build globally as the partnership between the village of Roberts and CLEARAS Water Recovery Inc. prepares to unveil the first full-scale Advanced Biological Nutrient Recovery system in the world.

CLEARAS’ ground-breaking ABNR technology harnesses algae's’ appetite for nutrients in a carefully controlled continuous flow environment to remove harmful pollutants from municipal wastewater to deliver effluent that meets the highest water quality standards.

”It’s exciting to be the first one in the world with this. Looking at the possibilities that will be here for the treating process, it’s exciting as an operator. I truly expect to be able to put out drinking water quality effluent,” Roberts Public Works Director John Bond said.

Compelled by the Wisconsin Department of Natural Resources to lower its phosphorus discharge level from 4.0 to 0.04 milligrams by liter by Dec. 31, 2020, the village began researching solutions in 2015. A number of solutions were investigated including, different chemical treatments, pollutant trading, microfiltration and an economic variance.

In the end, the village signed a $3.6 million contract in 2018. The CLEARAS solution proved to be a more sustainable, more comprehensive, more flexible and more cost effective solution, they said. The CLEARAS system not only addresses the immediate phosphorus issue, it removes or reduces other pollutants likely to be regulated in the future and it produces an algae product that will be sold to return a revenue stream to the village.

To sustain optimal conditions for algae growth 24/7, the photobioreactor is supplemented with special light to keep growth consistent regardless of conditions. The lights provide a combination of light in red and blue wavelengths controlled by photoactive radiation sensors. Tom Lindfors / RiverTown Multimedia
To sustain optimal conditions for algae growth 24/7, the photobioreactor is supplemented with special light to keep growth consistent regardless of conditions. The lights provide a combination of light in red and blue wavelengths controlled by photoactive radiation sensors. Tom Lindfors / RiverTown Multimedia

“In addition to phosphorus, the ABNR process will also remove nitrogen, total suspended solids, biochemical oxygen demand and pathogens such as E. coli and fecal coliform. There is also the added benefit of the reduction of some metals commonly found in wastewater,” said Autumn Fisher, regional director of project delivery for CLEARAS.

Through a unique application of biomimicry, ABNR injects a biodiverse blend of algae into the influent wastewater, pumps that mixture in a photobioreactor consisting of more than seven miles of glass piping igniting a photosynthetic reaction. In combination with the phosphorus-rich wastewater and sunlight, the algae blooms consuming the phosphorus, nitrogen and other nutrient pollutants.

“We’re balancing what is referred to as the food, which is the phosphorus and the nitrogen, and the organisms, which is the algae. You have to make sure the algae has enough to eat. They will eat the food and then on the backside, we have to remove some of the algae because it’s growing, eating and reproducing. The mixture serpentines through the glass tubing entering at the bottom exiting out at the top of two separate bioreactors stacked on top of one another,” Fisher said.

That mixture passes through a filtration processing tank where a membrane separates the algae from the cleaned water.

In addition to separating out the algae, the membrane filters out particulates the algae doesn’t eat including pathogens like bacteria and some heavy metals.

Part of the algae is recirculated, looped back into the influent mix to continue the recovery process while another portion of the algae is harvested as algae biomaterial. The portion to be harvested is fed into a centrifuge where it is spun into a thick paste enabling the mixture to be dried more easily and less expensively.

“At design conditions, the ABNR system is expected to generate as much as 400 pounds of algae biomaterial each day or 146,000 pounds a year and the algae has a gross value between $0.50 - $1.00 per pound,” Fisher said.

Through a unique application of biomimicry, ABNR injects a biodiverse blend of algae into the influent wastewater, then pumps that mixture in a photobioreactor consisting of more than seve miles of glass piping igniting a photosynthetic reaction. The Roberts facility will be a full-scale first in treating sewage. Tom Lindfors / RiverTown Multimedia
Through a unique application of biomimicry, ABNR injects a biodiverse blend of algae into the influent wastewater, then pumps that mixture in a photobioreactor consisting of more than seve miles of glass piping igniting a photosynthetic reaction. The Roberts facility will be a full-scale first in treating sewage. Tom Lindfors / RiverTown Multimedia

Since the ABNR system addresses the phosphorus issue, it should also eliminate the usage of aluminum sulfate saving the village $25,000-$30,000 annually.

After suffering some setbacks due mostly to the weather this past winter, construction of the ABNR addition to the wastewater treatment plant is back on track and scheduled to be fully functional by August.

”I would say probably the biggest challenge has been, because there isn’t anything like this, educating the contractors on how to put it together. They had nothing to go by, however, CLEARAS has been very involved. There’s been someone here from CLEARAS every day pretty much from the beginning. They’ve been great,” Bond said.

The final components of the glass photobioreactor and filtration system were installed at the end of June, setting up the complete system for commissioning in July.

During the commissioning process the entire system is tested with clean water to make sure there are no leaks and that all of the mechanical, technical and digital components of the system are functioning properly.

In August, the system will be inoculated with algae, the proper balance will be determined and implemented and the system will be fully functional.

”Once we inoculate and we put the algae in, we’ll have to give it some time to actually grow. We refer to it as the appropriate total suspended solids. It has to get to the right density. Then we’ll actually start treating water,” Fisher said.

The Roberts plant was designed to process up to 450,000 gallons of effluent a day. It currently processes about 100,000 gallons a day.

The CLEARAS ABNR system is designed to handle up to 150,000 gallons a day with the capacity to expand as needed.

CLEARAS has other ABNR systems around the country processing wastewater at rates from 50 gallons a day to 15,000 gallons a day, but this will be the first full-scale continuous treatment facility in the world.

Not many weeks go by where Bond or CLEARAS co-founder Kevin McGraw are not giving a tour to a visiting municipality investigating whether ABNR might be the answer to their wastewater treatment.

Roberts is paying the price, they are the guinea pig for a lot of other communities that when the time comes will not have to go through this whole learning process and that is very valuable.

”Roberts is doing everything possible to protect our resources with this project. It’s exciting,” Bond said.

CLEARAS has also learned in the process.

“As a company, we’ve learned what to do to improve the process, things that we would do the same and things that we would do differently for the next project,” Fisher said.

To see time-lapse videos of the construction of the Roberts facility and for more information about ABNR, visit CLEARAS Water Recovery, Inc. at: clearaswater.com.