What Is the R2E2 Solids Handling Facility?

It’s a $169 million upgrade for NEW Water in Green Bay, but the new solids handling facility is estimated to save millions each year. Here’s more on the technology and training being used.
What Is the R2E2 Solids Handling Facility?
Digital imagery of the two new anaerobic digesters being installed at NEW Water in Green Bay.

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R2E2 might sound like a Star Wars malapropism, but it’s actually the name of the new wastewater recovery and reuse system under construction at NEW Water in Green Bay, Wisconsin. R2E2, which stands for Resource Recovery and Electrical Energy, is a multiyear, $169 million project that will replace an aging solids handling facility, help meet stricter environmental regulations and increase solids handling capacity.

“The project harnesses recovery of nutrients and gas for cost savings and environmental benefit,” says Nathan Qualls, director of technical services.

A brief history
NEW Water — the brand of the Green Bay Metropolitan Sewerage District — operates the third-largest wastewater treatment plant in the state. It began researching and planning the R2E2 project in 2008. Construction started last year and is to be completed by 2018. The company started rate increases in 2013 to help pay for the project.

NEW Water’s Green Bay facility began operation in 1935 but has had many upgrades since. The current plant, built in 1976, was the first wastewater treatment facility in the nation to treat both municipal and paper mill wastewater. The plant, which processes an average of 30 mgd and a maximum of 120 mgd, will see processing efficiencies and cost benefits with R2E2.

Electrical energy
The project’s design includes two anaerobic digesters — a technology NEW Water used in the 1930s, but abandoned in the 1970s. Two 2.2-million-gallon silo-type digesters will break down primary and waste activated sludge. Biogas will be burned in engine-generators to produce electricity for the plant. The waste heat from the engines will be recovered to heat the digesters and supplement sludge drying and building heating.

Engine-generators will provide 4 MW of capacity, about equal to the plant’s current demand. Greenhouse gas emissions will be reduced by about 22,000 metric tons per year, and energy costs will be reduced by 50 percent — an estimated $2 million per year.

“It is a reduction in operating costs and relieves rate pressure,” says Qualls. “And I think the savings will increase as time goes on. This further insulates us from cost increases.”

The process includes a receiving station that will let NEW Water bring in high-strength waste from cheese, dairy, brewing and food processing industries for co-digestion, producing more biogas. Iron sponge technology will remove corrosive hydrogen sulfide from the biogas, and the gas treatment system will also remove siloxanes that can build up and damage engine parts.

“We’re being proactive,” says Qualls.

Resource recovery and new technology
R2E2 will also recover phosphorus as struvite that will be sold to Multiform Harvest Inc. of Seattle as an ingredient in commercial fertilizer, generating up to $400,000 in annual revenue.

“Treatment plants with anaerobic digestion are prone to having struvite buildup in pipes,” says Qualls. “This technology precipitates struvite out of the liquid stream in reactors.” 

The R2E2 system will replace two multiple-hearth biosolids incinerators with a much more efficient fluidized bed incinerator, the only one of its kind in the state used for biosolids, according to Bruce Bartel, treatment manager.

Three new centrifuges will improve dewatering, and a disc dryer will produce biosolids at 39 percent solids for feed to the incinerator. Dryer material means less energy required for incineration.

“We’re using the waste heat from the incinerator to dry the sludge in the disc dryer. That’s kind of a cool thing.”

Long road of training
To prepare for R2E2, a massive effort is underway to train the staff, including three treatment leaders, one operations trainer, 17 operators and four limited-term employees. Bartel says that since project inception, treatment leaders have been involved in each step, including consultant leader, design work and facility design. As the project completion nears, each leader will work with a project coordinator.

“It’s really a big step to have somebody involved from Day One,” Bartel says.

NEW Water is training four limited-term employees — who will remain on board through 2018 — to run the existing areas of the plant while the main staff works on R2E2. The four limited-term operators will run NEW's De Pere facility and the liquids section (non-R2E2 processes) of the Green Bay facility. The full-time treatment staff, including manager, leaders, trainer and operators, will start up and optimize the new R2E2 processes. 

Learning the ins and outs of anaerobic digestion will be key for the operators. “The operators will do some job shadowing at other wastewater treatment facilities, mostly in Wisconsin,” Bartel says. For now, they observe the progress of construction once a month.

In a “train the trainer” approach, one operator will focus on anaerobic digestion; one on centrifuge dewatering, and one on fluid bed incineration; then they will train their peers.

Bartel calls R2E2 the largest project he has seen at NEW Water in his 31 years there.

“I enjoy starting up equipment and new processes,” he says. “I think it’s an exciting time.”



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