Borough could someday turn waste into watts

PALMER — Yesterday's newspaper and last night’s dinner could one day power light bulbs or help grow Valley crops.

That was the message from a Minnesota-based Clark Engineering, who made a pitch to the Mat-Su Borough Wastewater Advisory Board Wednesday afternoon for a cutting-edge design for a proposed septage and leachate plant.

Leachate in this case means the liquid byproduct of the borough landfill, and contains the fluid that drains off of compacted trash when rainwater falls through it. Septage is the fluid removed from a septic tank.

Both plants would use a proprietary set of membrane filters to remove contaminants, ultimately producing water clean enough to drink without using chemical additives. A system that could filter 2 million gallons of leachate each year — the borough produces about 1.4 million gallons each year presently — would fit in a 10-foot by 13-foot footprint, said Kazem Oskoui, a representative from Clark. The plant would be modular, meaning capacity at the plant could be scaled up, and additional components could be added to adjust changing EPA regulations. The facility could be accessed and controlled via a smart phone.

“We don’t really need acres of land, we don’t need a lot of ponds, or anaerobic, aerobic digesters, we don’t need any of those things, no pretreatment whatsoever,” Oskoui said.

The borough generates about 14 million gallons of septage per year, and the plant would be able to handle about 20 million gallons per year, Clark representatives said.

Borough officials hope the septage could be refined enough to generate biosolids for use on local farm fields. However, because septage is relatively consistent, while leachate can vary depending on what flows out of the dump, the two streams would need to be segregated, said Clark representative Vladimir Scheglowski.

“We understand that the farming community here is historic, and I wouldn’t want to have leachate on my land,” he said. “I’m sure they don’t want to see it in their fields, either.”

Clark estimated the leachate facility would cost $4.2 million, and the septage facility would cost about $7.6 million, for a combined cost of about $11.8 million. The company reported both estimates without a detailed engineering assessment of the site, and traffic issues along North 49th State Street — where weekend lines of trucks can sometimes be an hour long — could require the construction of an additional access point to the borough landfill to accommodate increased traffic.

Clark representatives also discussed combining wastewater from the borough with sorted trash and recycling, particularly paper goods. The combination would be fed to bacteria, which would devour it to consume methane, which could then be burned to generate electricity, said Abi Assadi, another Clark engineer. He estimated a plant working with the volumes generated by borough users could have a maximum capacity of about 4.5 megawatts. That’s a relatively small amount compared to, for example, the 171-megawatt Eklutna Generation Station operated by the Matanuska Electric Association. Clark officials did not include a projected cost for the waste-to-energy option.

However, a proposal to resolve wastewater uncertainty, slow the growth of the landfill, and generate additional revenue is attractive, said borough environmental engineer Mike Campfield. The cost of integrating some wastewater and garbage treatment could add to the total cost, but might bear closer scrutiny, he said.

“You make money on two ends if you can make this happen, if the costs bear out,” he said. “You save money that you can avoid by not building the next cell, not closing the next cell.”

Officials have been examining alternatives for wastewater treatment since 2012. Wastewater is currently hauled to the Anchorage wastewater treatment plant, which operates under a special permit that allows the plant to release treated sewage into Cook Inlet. Anchorage officials have said they won’t accept wastewater from the Valley over concerns that doing so could affect their EPA license.

Last year, the borough assembly selected the landfill as the best possible piece of borough-owned property on which to locate a plant. They also sought $22 million in loans from the state government to cover the cost of constructing such a plant.

The next meeting of the wastewater treatment advisory board will be July 28.

Contact reporter Brian O’Connor at 352-2270, brian.oconnor@frontiersman.com, or on Twitter @reporterbriano.