In early December, the town expects to seek competitive bids for the construction of the Hawleyville sanitary sewer system expansion project, a town official said this week.

Fred Hurley, director of public works, said that bidding documents for the project are being refined to explain to bidders the work required for the project.

At a February 2014 town meeting, voters by an 81-11 margin approved borrowing $2.8 million to expand the Hawleyville sewer system as a means to spur local economic development.

Mr Hurley said he expects the town will receive many bids from firms interested in constructing the expanded sewer system.

If the bidding process proceeds as expected, the bids would be returned to the town after January 1, and the town would award the construction project to a firm by February, Mr Hurley said.

Fuss & O’Neill, Inc, of Manchester, the town’s consulting engineering firm, has been developing plans for the project with the town’s Water and Sewer Authority.

As currently planned, the expanded sewer system would extend from its current terminus near 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 also extend eastward alongside Mt Pleasant Road.

The sewer system would extend to 90 Mt Pleasant Road, a 34-acre parcel where a developer is expected to formally propose the construction of a high-density residential complex.

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

Of the sewer system expansion, Mr Hurley said, “It’s really not a complicated build.”

The project is expected to take about six to eight weeks to construct, he said.

Because most of the sewer lines in the expanded system will be low-pressure sewer lines, and not conventional gravity-powered sewer lines, the trenching required for sewer installation would only be about four feet to five feet deep, he said.

In conventional sewer systems, trenching, in places, may be very deep, based upon an area’s topography.

Mr Hurley said that town officials are considering whether conventional open trenching or pipe-jacking would be done in places where the new sewer lines would need to cross below state roadways. In pipe-jacking, sewer pipe sections are inserted into small lateral tunnels that are created beneath roads.

Mr Hurley said that, so far, the owners of about 20 properties have indicated that they want sewer line stubs installed at their properties so that they can connect to the expanded sewer system.

Because the low-pressure sewer system extension project involves the use of many individual “grinder pumps” to propel sewage through narrow-diameter lines, the design variables for the sewering project are somewhat 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.

The town built its gravity-powered central sewer system in the borough and adjacent areas to resolve longstanding groundwater pollution problems caused by failing septic systems. The central sewer system, which discharges wastewater at a Commerce Road sewage treatment plant, started operation in 1997.