Three Rivers Clean Water (CWP) director James J. Baker spoke on the need for Constantine to cover the cost of a force main improvements project at the Constantine Village Council meeting Monday evening (March 4). The estimated cost of the project is $75,592.13.
A letter written earlier by Baker to Village Manager Mark Honeysett, included a history of the force main piping used to carry Constantine’s sewage to the CPW plant. It was reviewed by the council, before a question and answer session with Baker. In the letter, Baker said the Constantine system has been in operation since 1998. There are a total of 17 air release valves (ARVs) with a primary function of releasing air, or in some instances, to equalize a vacuum created by wastewater traveling downhill during pumping cycles. Trapped air pockets within the force main create excessive operation pressures and increase the wear on pumps. Vacuum conditions within the force main fatigue the ductile iron pipe and could contribute to the failure of the force main. All 17 ARVs in service must operate automatically during every pumping cycle. Routine flushing of the ARVs is recommended semiannually. The design life of an ARV is 15 years according to the American Society of Civil Engineers. In the spring of 2012, CWP management began to locate, identify and prioritize failed and damaged ARVs.
“In October-November of 2012, CWP staff performed an exhaustive evaluation of the entire force main and determined 16 of the existing 17 ARVs had failed or were in poor condition,” Baker told the council. “The cost to remove, rebuild, then re-install the units was 95 percent to 110 percent of the cost of a new unit, so the decision was made to accept bids for replacement of all 16 units, and purchase two spare units,” he said.
In addition to the ARV work, there needs to be replacement of the high pressure seal water pumps and the calcium nitrate pump, Baker said. “The existing seal water pumps have been rebuilt several times since they were originally installed in 2003. The booster station has only one of two pumps operating, and the loan pump has bad bearings and a worn coupling.”
Baker added the two pumps at the high lift station routinely overheat and are only capable of serving one main sewage pump at a time.
The existing calcium nitrate pump has also been in service since 2003 and, despite two complete rebuilds, the pump’s performance is declining.
Baker urged the force main project be completed by September 1, 2013. He recommended Constantine hire W. Soule & Company of Portage to do sewer force main improvements at a cost of $70,270. A second bid of $70,500 was received from L.D. Dosca & Associates in Kalamazoo.
In a letter introduced to the council, Project Manager Randy McDaniel from W. Soule gave a breakdown of what the money would go for. It included 18 change-out replacement vent valves (with two kept as spares), purchase and installation of four Grundfos vertical seal water pumps, and a calcium nitrate pump.
“You could delay this decision three or four months, but a year or more is questionable. It’s not going to get any cheaper,” Baker said.
Honeysett said, “The system’s 15 years old. We’ll run into more repair costs. We’ve been fortunate already it hasn’t failed all at once.”
The motion was made to accept the bid from W. Soule & Company, and passed unanimously. Honeysett said money had already been budgeted for the project.
Source: Story and photo contributed by Angie Birdsall.