The Chelsea Standard
A Heritage Newspaper
Weekly Publication
ClariCone system for Chelsea
By Edward Freundl, Heritage Newspapers
PUBLISHED: January 25, 2007
Longstanding concerns with Chelsea's water system came one step closer to being resolved Tuesday following City Council action on several issues. Council members approved four major items involving the reverse osmosis (RO) treatment process used to treat the city's drinking water supply.
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The recommendations were formulated at study sessions earlier this month.
One unresolved issue is proper disposal of the concentrated waste byproduct created by the RO filtering process at the Water Treatment Plant (WTP).
The concentrate has been running through the Wastewater Treatment Plant (WWTP) process, then discharged into Letts Creek.
However, the Michigan Department of Environmental Quality recently tightened its limits on levels of chemicals and other substances in the treated discharge.
In addition, the volume of water-based concentrate has been causing severe capacity problems at the Veterans Park pumping station and the WWTP.
Whenever the WWTP exceeds its capacity, the RO system must be shut down until the flow is minimized.
Council members decided to authorize a study of two alternatives that would essentially filter the concentrate a second time, resulting in recovery of a substantial volume of clean drinking water and reducing the amount being sent through the WWTP.
One is a proprietary system known as ClariCone, and the other uses lime to treat the dissolved solids.
Councilman Frank Hammer requested more details about the costs and other parameters of a pilot study of the alternatives before voting to authorize it.
"We're already throwing away 400,000 to 450,000 gallons a day," he said. "The ClariCone system will recover about 80 percent, making potable water out of waste, which will help our treatment plant."
Steven Wright, chairman of a citizens committee on water issues, asked the council to continue working with the state on an acceptable discharge level.
"One of the things I'd like to see at the same time is the discussion with the DEQ go forward," Wright said.
"The state has issued a provisional permit, and it doesn't hurt to find out what options you have."
To keep things moving, the council voted to approve a compromise measure that authorized a request for proposal to conduct the study, with cost and design information to be presented at the council's next regular meeting.
Compromise was necessary to approve a second item: spending an estimated $15,000 for installation of electronic controls that would automatically shut down the RO system in the event of an overflow at the Vets Park pump station.
Hammer favored the idea, saying it was necessary to ensure a constant volume of water sufficient for the city's needs.
"It removes human error, and I think it's the most appropriate thing the city can do," he said.
Not surprisingly, the proposal ran into opposition from WTP Superintendent Rob Jones, who preferred having the ability to shut down the system manually.
"With your concern being public safety, go ahead and install the equipment but I'd still have someone go out there and find out what's going on," Jones said.
Even though they involve an estimated half-million dollars, the two remaining items were fairly straightforward and approved as submitted.
A recommendation from a recent sewer evaluation study was to replace the 8-inch main from the Vets Park station to the WWTP with a 12-inch line, and to upgrade the station with new, variable-drive pumps.
Engineers estimate the cost of the design and construction at $350,000, and the city will seek state bond funds to pay for it.
The final recommendation was to convert the RO system from a three-stage system of membranes to two stages, and install a booster pump.
Tetra Tech engineers said the number of membranes would remain the same, just configured differently.
The output of permeate, or softened water, would remain virtually the same at about 75 percent, but the system could be operated at lower pressures and it would be easier to clean the membranes.
The booster pumps would improve the process of blending the permeate with raw well water to produce water within acceptable ranges of hardness and softness.
The cost for the RO conversion was estimated at $100,000 and the cost of the pump at $33,000.
The council authorized spending up to $150,000 after City Manager Mike Steklac urged them to include a contingency fund.
"I think it's extremely important to let citizens know we are making progress and moving forward with this," Councilman Jamie Bollinger said.
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