Bismarck will go ahead with expansion of its sewage treatment, a project it put on hold last year to research a proposal by LAS International Ltd. using the resources of nationally known HDR Engineers Inc.

At Tuesday's meeting, the Bismarck City Commission, minus Mayor John Warford, heard presentations from HDR and LAS International. HDR's Henry Benjes Jr. and Joe Middlebrooks explained and defended HDR's evaluation of LAS International's proposal, while Dileep Thatte, of LAS, and Richard Nored, of HGE Inc., refuted the evaluation's claims concerning cost, land use and efficiency.

Presenters were given limited time to make their cases, then commissioners followed up with questions, mainly focused on the issues raised by LAS's rebuttal to the evaluation and HDR's credentials to provide an accurate assessment. In the end, commissioners sided with HDR's findings and decided to go ahead with expansion.

Benjes and Middlebrooks said the LAS lagoon proposal called Aero-Fac would struggle to meet permit standards without additional treatment and would require periodic removal of sludge, which could be difficult to dispose of.

Commissioner Bryce Hill asked if any of the current system could be salvaged if the city were to choose the LAS lagoon system. Benjes said at best 5 percent of the system could be used.

"After listening to the discussion, I'm not willing to throw away a $21 million investment, and find it hard to support LAS," Hill said.

Commissioner Dave Jensen suggested the city should be concentrating on providing a separate system to serve north and northeast Bismarck, and didn't like the idea of moving all the sewage across town to the system located in the southwest. Commissioner Sandi Tabor said she didn't disagree with Jensen, but the question before the commission was what to do with the existing treatment plant.

On a 3-1 vote, the commission approved expanding the existing treatment facility. Jensen cast the dissenting vote.

Keith Demke, director of utility operations for the city, said the next step is to contact SEH Inc. for design of the next phase of the expansion. The company had been awarded the work, but was put on hold last summer so the LAS proposal could be researched.

"The first thing we'll address is the headworks, which generates most of the odor. It's a 25-year-old building and there really isn't anything we can fix, and we'll have to start from scratch," Demke said.

Much of the equipment at the treatment plant will be replaced due to its age. The new equipment will be designed to handle greater volumes as the city grows in the next 20 years.

(Reach reporter Gordon Weixel at 250-8255 or gordon.weixel@bismarcktribune.com.)