Ten years ago, leaders with NEW Water, part of the Green Bay Metropolitan Sewerage District, determined a new solids recovery facility was a necessity.
In June, NEW Water’s innovative Resource Recovery and Electrical Energy (R2E2) generation system will be fully operational.
Credit: NEW Water
The new system represents a shift in process and philosophy for wastewater and solid treatment.
It allows NEW Water to view waste as a resource to recover rather than something to dispose of, said Thomas Sigmund, executive director of NEW Water, which services 15 municipalities in the greater Green Bay area and handles approximately 38 million gallons of wastewater daily.
“As we got into the project, we saw an opportunity to go beyond just what we had to do and get more into resource recovery,” he said. “We saw the value in the materials coming in to us. They were not waste, but a resource that could be recovered.”
The first-of-its-kind, $169 million solids recovery facility brings together multiple technologies in one location.
“The different components, such as using a digester, are used elsewhere, but this is the first time they’ll all be in the same facility,” he added.
The R2E2 only addresses the solid waste portion of what comes in to NEW Water.
According to Sigmund, the utility needed to build R2E2 because of its aging infrastructure, the demand for more capacity, and the stricter federal air permit environmental standards.
The R2E2 recovers waste in two ways. First, two anaerobic digesters break down biodegradable material in the absence of oxygen, which reduces the amount of material to be processed while creating methane gas that can be captured to produce electricity. Second, a nutrient recovery process removes struvite, a combination of magnesium, nitrogen and phosphorus naturally found in wastewater. The struvite is then collected and used in commercial fertilizer, Sigmund said.
The R2E2 also expands the type of materials NEW Water can accept, including dairy, sugar and food processing waste.
Credit: NEW Water
Currently, those materials are spread on nearby farm fields or put in the landfill.
“These wastes can increase digester energy production and provide a consistent and environmentally-friendly disposal outlet,” Sigmund said.
The facility is expected to reduce greenhouse gas emissions by an estimated 22,000 metric tons per year, which is equivalent to removing 15,000 vehicles from the road, and bring more rate stability for NEW Water’s customers.
“We are going to save $1.2 million each year by generating and using our own electricity and another $600,000 in natural gas,” said Sigmund, adding NEW Water will also make money selling the small white and gray pellets made during the recovery process to a fertilizer producer.
“Our customers will see the benefit of the new facility in their bills with more stable rates, since we have the built-in savings,” he said.
Additionally, the facility will be able to pull more phosphorus from materials coming in, which means reducing the amount of phosphorus that will enter area waterways.
Construction began on the new facility in 2015 after NEW Water worked with external stakeholders for several years to analyze the solids handling processes used by other facilities. Together, they developed a plan using the latest technology to build a facility that was reliable, safe, cost-effective and environmentally-friendly.
“It was important to make this a collaborative approach and have input from our stakeholders,” Sigmund said.
