By every measure, the sewer tunnel that Akron plans to build to resolve problems with its combined sewer system will be a behemoth.
The $200 million tunnel will be:
• 27 feet in interior diameter.
• Buried 150 feet below ground.
• More than one mile long.
• Able to store up to 25.6 million gallons of stormwater and raw sewage after heavy rains and snow melts.
Right now, the tunnel exists only as a concept, but details are emerging as engineering plans take shape.
The city is planning to begin construction on the giant tunnel in April 2014, said Richard Merolla, Akron’s deputy mayor, and James Andrew Hewitt, manager of the city’s Engineering Bureau.
It is “a massive undertaking,” Merolla said of the tunnel that is required as Akron works to solve its combined sewer problem that has fouled the Cuyahoga and Little Cuyahoga rivers and the Ohio & Erie Canal with untreated sewage for decades.
U.S. District Judge John Adams is expected to rule soon on a proposed consent decree involving Akron, the U.S. Environmental Protection Agency and the Ohio EPA to correct the sewer overflows by 2027.
The latest price tag of $890 million (in 2010 dollars) will increase service rates for about 300,000 sewer customers in Akron and 13 suburbs.
In March 2011, Adams rejected a similar agreement, saying the plan would take too long and did not provide specific dates for improvements. The plan since has been revised.
The agreement calls for zero untreated overflows from Akron’s sewer system, and such a rule would be among the strictest in the United States. Technically, Akron is agreeing to an 18-year schedule, with the clock already running.
The city has been operating as if Adams has signed the consent decree, making it legally binding, Merolla said.
“We couldn’t wait,” he said. “We have to do this. We have to start moving.”
The city had prepared what it calls an “aggressive timetable” to solve the sewer problem and intends to stay on that schedule and to avoid any costly penalties for delays in meeting court-approved deadlines, Merolla said.
Akron once had 34 sites for sewer overflows. Recent system improvements have eliminated seven, and the new tunnel will eliminate nine more.
The city has hired an engineering firm, DLZ — it has a new Akron office and operations in Ohio and four other Midwest states — to lead the design and engineering work on the giant tunnel. California-based Jacobs Engineering Group Inc. and tunnel experts Jenny Engineering Corp., from New Jersey, are involved as subcontractors.
Akron city engineers performed initial design work for the tunnel.
The southern terminus of the 5,550-foot tunnel will be near West Exchange Street and the Akron Innerbelt. It will go under the Innerbelt and run east of the Diamond Grille at West Market Street. It will then run north along Hickory Street and end south of Memorial Parkway.
The tunnel is scheduled to be operational Dec. 31, 2018.
The city and its land acquisition team have been busy securing rights-of-way and easements for the tunnel.
New treatment plant
The city also will build a high-rate treatment plant at the northern end of the new tunnel.
Water from the overflow tunnel would get micro sands and polymers added. That would enhance the settlement of solids from the water-sewage mix. The result would be clean water that would not require further treatment at the sewage plant.
The high-rate treatment plant would operate only when the flow surpassed the tunnel’s capacity, Hewitt said.
The plant would be capable of handling up to 300 million gallons per day. It would cost about $56 million. Bids would go out in 2024, with operations to begin in late 2027.
Limits have been set as to how effective the plant must be to clean the wastewater.
The city’s Long-Term Control Plan for the sewer system also calls for a second tunnel in North Akron. It will be 20 feet in diameter and 10,000 feet in length. It would be capable of storing up to 23 million gallons of water.
It would be bid in late April 2023 and would be operational by Dec. 31, 2026.
It would eliminate four overflows in North Akron.
The price tag: $146 million.
Akron will also be designing and building 10 smaller basins to store stormwater and reduce the immediate flow.
Those basins already are under design, Hewitt said.
The city is working on final design of the first, at Elizabeth Park north of downtown Akron. It will be capable of holding 1.4 million gallons. The water-sewage mix will later be released to flow to the sewage plant.
The 10 basins together will be capable of holding 22 million gallons from 14 sewer overflow sites.
The basins will be similar to the existing facility to the Little Cuyahoga River off Cuyahoga Street in North Akron. That basin, called Rack 40, was completed in 2006 and can hold up to 9.5 million gallons of water-sewage mixture. It cost $23 million and handles about 30 percent of the Akron overflows.
The city is looking at covering the basins, perhaps with concrete and soil and perhaps with aluminum domes, to minimize odors.
In addition, improvements are already under way at the city’s sewage treatment plant on the Cuyahoga River off Akron-Peninsula Road in North Akron.
In 2012, the city conducted a pilot project at the sewage plant to test a biological treatment method during 20 separate rainy events.
A small amount of the city’s sewage flow was diverted to the new ballasted clarification system that was housed in a trailer-sized facility for treatment, Hewitt said.
The system relies on coagulants, polymers and micro sands to remove pathogens, total dissolved solids and the biochemical oxygen demand.
Akron’s tests removed 85 percent to 95 percent of the solids and 40 percent to 65 percents of the biochemical oxygen demand, Akron reported.
That test data is being analyzed and could provide a better treatment method in the future, Hewitt said. Akron could add the system instead of making costly plant expansions, he said.
The pilot project was conducted with the approval of the federal EPA, he said.
The system has been used in Cincinnati and Port Clinton in Ohio.
It would provide full secondary treatment for up to 280 million gallons of sewage per day at the Akron plant, Hewitt said.
The full system will cost about $49 million and is scheduled to begin operations in April 2019.
In a related development, Akron has solicited proposals from five or six financial companies to help determine how much Akron sewer customers will have to pay for the combined sewer work.
Those proposals are due back in the next few weeks, and the city then will evaluate the proposals and pick the company, Hewitt said.
At various times in the past, city officials have said the needed sewer improvements could double, triple or quadruple sewer rates.
Bob Downing can be reached at 330-996-3745 or email@example.com.