Williams Brothers Construction LLC, of Spokane, is the apparent low bidder—with a $52 million bid—for a major improvement project at the wastewater-treatment plant that serves the city of Bozeman, Mont.

The project, which will more than double the plant's treatment capacity, also will raise water quality standards of the facility by removing a high degree of phosphorus and nitrogen from the treated wastewater the plant discharges, says Bob Murray, a project engineer with the city of Bozeman.

Principals at Williams Brothers were unavailable for comment.

"We're responding to big growth issues in Bozeman," Murray says. The city's most recent estimates put its population at more than 35,000 people, up more than 27 percent from the 2000 U.S. census of 27,500 people.

The Bozeman Water Reclamation Facility, which is north of Interstate 90 on the north edge of Bozeman in south-central Montana, discharges into the East Gallatin River. The improvement project will increase the plant's discharge capacity to 13 million gallons of treated wastewater a day, from its current treatment capacity of 5.6 million gallons per day.

The city's bid documents show the project will include demolition of some facilities, construction of a five-stage treatment facility, replacement of a chlorine disinfection system with a system that uses ultraviolet light, construction of an anaerobic digester, and installation of a biosolids dewatering system. The project also calls for the contractor to build structures to house the plant's administrative staff, system controls, and stored biosolids.

Murray says the city has until late November to review the bids before it awards the contract. He expects construction will begin this winter, and the project will take more than two years to complete.

Other bidders were Joseph J. Henderson & Son Inc., of Gurnee, Ill., with a bid of $52.6 million, and Cop Construction LLC, of Billings, Mont., with a bid of $55.5 million.

Williams Brothers specializes in construction of wastewater-treatment and fish-hatchery facilities, the company's Web site says. Its current projects include major wastewater-treatment system improvements for the city of Entiat in Central Washington.