The Water & Sewer Authority (WSA) is recommending a construction firm to expand the Hawleyville sanitary sewer system, a municipal infrastructure project intended to stimulate economic development near the Exit 9 interchange of Interstate 84.

At a March 10 session, WSA members unanimously recommended to the Purchasing Authority that the town hire the low bidder on the project, which is Centerplan Construction Company of Middletown. The Purchasing Authority, whose members are the first selectman and the finance director, is expected to act on that hiring recommendation.

The WSA made the recommendation based on the advice of its consulting engineering firm Fuss & O'Neill, Inc.

The town recently received 11 bid submissions for the sewering project.

The low bid for the overall project came from Centerplan at $2,858,260. The high bid for the work was from A. Julian Railroad Construction Company of Bridgeport at $4,636,450.

The bids submitted by the firms contain three work components: the basic sewer extension project; the construction of a sewage collector system at Midway Home Estates, which is a mobile home park at 160 Mt Pleasant Road; and the extension of a sewer line to 90 Mt Pleasant Road.

Before the bids were submitted, the town had estimated the construction costs at between $2.8 million and $3.2 million. The sewering project is expected to take 90 days to complete, after it begins.

Fred Hurley, town public works director, said March 15 the town would modify the planned bonding on the project, increasing it from $2.8 million to $3.8 million, to cover the overall cost of the project. The larger sum includes engineering services for the project. The town will have sufficient sewer-related revenue to cover the larger sum, Mr Hurley said.

Because the sewering project is intended to stimulate economic development, property owners with holdings adjacent to the planned sewer lines may connect to sewer system or not connect, based on their preference.

Mr Hurley said he expects sewer construction work to start in April.

At a February 2014 town meeting, voters by an 81-11 margin approved borrowing $2.8 million to be spent toward the Hawleyville sewer expansion project. The sewer expansion project's overall $3.8 million cost would be covered through assessments placed on the properties with sewer service and through grant money.

The expanded sewer system would extend from its current terminus at 164 Mt Pleasant Road eastward to the intersection of Mt Pleasant Road and Hawleyville Road. From that intersection, the sewer system would extend northward alongside Hawleyville Road, and would also extend eastward alongside Mt Pleasant Road to 90 Mt Pleasant Road, where there is a 34-acre parcel that is expected to be developed.

The expanded sewer system would provide wastewater disposal for a planned mixed-use complex off Hawleyville Road, which would hold a 180-unit rental apartment complex, a church, and a diner.

Many of the sewer lines in the expanded system will be low-pressure sewer lines, which require trenches only four to five feet deep. Areas with gravity-powered sewers would require deeper trenching.

Because the low-pressure sewers involve the use of many individual "grinder pumps" to propel sewage through narrow-diameter lines, the design variables for the sewering project are more complex than that of a conventional gravity-powered sewer system.

The Hawleyville sewer system, which started operation in 2001, discharges wastewater to a regional sewage treatment plant in Danbury.