| Cutting-edge treatment facility to transform sewage into green energy
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Cutting-edge treatment facility to transform sewage into green energy

A Maryland water and wastewater utility is plunging into its largest and most innovative project ever — turning poop to power. 

Image of the future bioenergy facilities at the Piscataway Water Resource Recovery Facility.WSSC Water serves almost 2 million residents and covers a service area of nearly 1,000 square miles in central Maryland. The utility is three years into a five-year, $271 million effort to build the Piscataway Bioenergy Project. Once complete, the facility will revolutionize the way WSSC Water handles biosolids — the waste leftover from sewage treatment — by cutting greenhouse gas emissions 15% and saving $3 million each year in operating costs. (Pictured right, image of future bioenergy facilities at the Piscataway Water Resource Recovery Facility.)

“It’s a very green process, certainly much more than our current one,” said Theon Grojean, WSSC Water’s division manager for facility design and construction. 

Almost 15 years ago, WSSC Water began researching ways to more efficiently remove its Class B biosolids, which have strict disposal requirements. Landfills were starting to reject the waste, and applying it on farmland is highly regulated, expensive and inefficient, requiring truck after truck of refuse. 

Three years ago, the area was hit with several rainstorms, and the saturated agriculture fields WSSC Water typically uses for disposal could not accept the biosolids. There was nowhere to go with the leftover sewage.

“It was a mad scramble to try to find space to store all the waste until the fields dried out,” Grojean said.

That scramble underlined the need for the Piscataway Bioenergy Project. 

Producing cleaner biosolids

Theon GrojeanThe new facility, built in Accokeek, Md., on the site of an active wastewater treatment plant, combines two processes — anaerobic digestion and thermal hydrolysis — to break down the sludge and produce much cleaner Class A biosolids, which can then be used as lawn and garden compost.

The process produces methane gas, which WSSC Water will capture and upgrade to natural gas to power the engines and generators within the plant, saving ratepayers $3 million each year in energy costs.  

“This is easily the largest construction project we’ve ever undertaken,” Grojean said. “It’s a quantum leap from where we were.”

Though this process has been on the market for a while, mostly in the United Kingdom, only a handful of utilities in the United States have tried it, including WSSC Water’s neighbor, DC Water. 

“They gave us such good advice, and now we’re passing on that advice to others who are reaching out to us,” said Stanley Dabek, WSSC Water’s project manager, who has managed phone calls and site visits with officials from New Zealand, Virginia, Minnesota and other utilities interested in the project. 

Wins for customers, environment

WSSC Water’s five wastewater treatment plants, now called water resource recovery facilities, will send their waste to the new site. Currently, the five facilities produce about 8,000 tons of Class B biosolids each month. Once this effort is complete, the amount of biosolids will be halved, renewable energy will be generated, and the need for odor-controlling lime will be eliminated – saving customers millions. 

“There are multiple wins in this one project,” said Chuck Brown, WSSC Water’s director of communications and community relations.

Stanley DabekOfficials say the project can serve as a model for other utilities, illustrating how they can confront climate change with innovation and resiliency. And they’ve learned a lot along the way, from how to develop a construction contract that was unlike any the utility had used in the past, to how to select a design-build contractor.    

“The process is very complicated, novel to us. Operations will need to learn how to operate and maintain the plant,” Dabek said. “I can’t stress enough how detailed this project is. It’s not like anything I’ve worked on in my career.”

It may be some time before Maryland residents can purchase the utility’s Class A biosolids in the form of lawn fertilizer; for now, WSSC Water plans to dispose of it via land application.

“But we’ll be disposing of a much cleaner product, and about half of the product,” Grojean said. “It’s a green process. We are capturing the methane from anerobic digestion, creating natural gas, using the heat generated and circling it back around.” 

The project is on track to begin operating in late 2024.