Milwaukee Metropolitan Sewerage District engineers are trying to line up an alternative methane pipeline route to avoid the trouble of building through a dense urban area.
“The closer we get into the city, a number of issues come up,” said Mike Martin, MMSD technical services director. “It’s just purely the congestion because of utilities and traffic.”
The district is bidding out construction of a pipeline to transfer methane gas from the Emerald Park Landfill in Muskego to Milwaukee, where the gas will be burned to power the district’s Jones Island sewer treatment plant. The pipeline construction was estimated at $19.7 million in the district’s 2010 budget.
The district could build a 19-mile pipeline, but MMSD is negotiating to buy an existing petroleum pipe built in the 1960s east of General Mitchell International Airport. If the district can buy the pipe, it can shave five miles of pipe construction off the project and avoid a route through densely developed areas in Greendale, Greenfield and Milwaukee.
Buying the existing pipeline would let the district avoid the unknowns involved in digging through older urban areas, Martin said. But the new construction route takes the pipeline past more properties where there may be contaminated soil, which could add remediation costs to the job, he said.
There also are more safety concerns with the new construction because there are more underground utilities that were built years ago and weren’t mapped accurately, Martin said.
“The risks are simply higher,” he said, “because you think you know where the utilities are, but you don’t.”
Just one abandoned, unmapped utility can stop construction of a project as builders call for someone to identify the pipe, said Tom Zywicki, operations supervisor for Hawk Construction LLC, Slinger. Zywicki and company President Ron Spoerl were two of the 70 builders who attended the MMSD pre-bid meeting Tuesday for the pipeline project.
Hawk Construction finds underground pipes by using a vacuum to suck up dirt and create a hole without disrupting the utility line. Zywicki and Spoerl are looking for subcontracts to locate utilities during the project.
“There’s a lot of unknown pipes and stuff there under the ground,” Zywicki said. “It all depends on where you are going through. In the city, you are going to have your sewer laterals and water laterals and cable TV lines.”
The district is asking contractors for two bids for the pipeline project to cover both potential routes. Martin said the district is still negotiating with the owner of the existing pipeline that offers the cheaper, easier route.
District officials would not name the pipeline owner because negotiations are ongoing. Martin said he expects the district to pick its final route in April.
Even if it must take the more complicated and expensive option, Martin said, the district expects the project to eventually save the district money by lowering the utility bills for running the treatment plant.
“If the pipe construction comes in cheaper,” he said, “that’s just icing on the cake.”