TRAVERSE CITY — City and township sewer users could face significant rate increases over the next three years to replace treatment plant components that convert sewage into near-drinkable water.
The city-based water treatment plant uses special filters known as membranes, which are close to exceeding their useful life and need to be replaced, according to a report by an engineering consultant from CH2M HILL, the firm that operates the plant.
The replacement cost for the membranes is $825,000 per tank, and there are eight tanks for a total estimated cost of $6.6 million.
“The cost to the city could be substantial,” said Mayor Michael Estes. “Somehow, I think we are going to have to deal with some kind of rate increases.”
The Grand Traverse County townships of Garfield, East Bay, Peninsula, Acme, as well as Elmwood in Leelanau County, all use the plant and would pick up a little less than half the cost if the city decides to dive into repairs now.
That percentage could change; the city would pick up 60 percent of repair costs if officials wait until after 2014, when the townships’ 8 percent plant lease agreement expires.
Some township officials are hesitant and want to learn more before committing to repairs.
“It’s entirely possible we need to do something, but I’m skeptical,” said Chuck Korn, Garfield Township’s supervisor. “I think the desire is to do it when the township is responsible for paying 48 percent.”
City commissioners and officials with the Grand Traverse County Board of Public Works -- who represent the townships -- will meet in a joint study session on Monday at 7 p.m. in the Governmental Center to receive a report from CH2M HILL.
The consultants recommend the city and townships replace one or two membranes early in 2014 and set aside enough money in 2015 and 2016 to replace remaining membranes as they fail.
The cost to city sewer customers would be about $65 a year, or an increase of a little over $5 per-month to cover membrane replacement costs for one tank. The cost to cover all eight tanks in three years would require a rate hike of about $15 per-month. The city also could consider borrowing the money, which would lower the rate increase but extend it over a longer period of time.
Mike Slater, director of the county’s Department of Public Works, said any need for rate increases will vary by township.
“A lot of it will depend on what they have in their (individual) sewer funds,” Slater said. “Some of the funds are pretty flush.”
The city has no cash reserves in its sewer fund because it funneled money into replacing its aging sewer lines amid ongoing major street repairs, said city Treasurer Bill Twietmeyer. The city could loan money from one of its other funds, or cancel a budgeted sewer replacement project to cover an initial, single replacement.
There’s no indication existing membranes have become problematic, Korn said. He contends former City Manager Ben Bifoss initiated the membrane review by the plant operator, CH2M HILL, based on the city and townships’ expiring lease agreement.
The consultant’s report acknowledged no problems with the existing membranes, but warns the devices won’t last forever.
“The current membranes have peformed well, and there have been no signs of imminent membrane failure,” wrote report author Scott Levesque of CH2M HILL.
But membranes in similar installations tend to last eight to 10 years; Traverse City’s were installed in 2004. The membranes also occasionally clogged because of a biological reaction, but officials don’t know if new membranes would resolve the issue.
CH2M HILL recommends buying one or two membranes now so experts can determine if the devices resolve the clogging problem. The replaced membranes would be re-installed in remaining tanks to increase the filter area, a move that would help alleviate problems from membrane clogging should it occur during peak summer sewer flows.
“It’s going to have to be done,” Estes said. “How we spread out the cost is a separate question. We pride ourselves on our water quality here and I think we need to put our money where our mouths are.”