An informational session to explain the construction aspects and cost implications of the planned expansion of the Hawleyville sanitary sewer system is scheduled for Thursday, May 8.

The meeting, which is sponsored by the Water & Sewer Authority (WSA), is slated for 7 pm in the lower level conference room at Town Hall South, 3 Main Street. A regular meeting of the WSA will immediately follow.

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

Expanding the Hawleyville sewer system is intended to make several large undeveloped properties there more attractive to the developers of commercial/industrial projects. Those properties are in the general vicinity of the intersection of Mt Pleasant Road and Hawleyville Road.

The area already has access to public water, natural gas, electric, and communications utilities.

Unlike the central sewer system, which started operation in 1997 to resolve longstanding groundwater pollution problems due to failing septic systems, the Hawleyville sewer system started operation in 2001 to stimulate local economic development.

The Hawleyville sewer system expansion would extend sewer mains from 166 Mt Pleasant Road eastward along Mt Pleasant Road to its intersection with Hawleyville Road. The sewer mains also would extend northward along sections of Hawleyville Road and Covered Bridge Road.

The planned expansion will not extend sewer mains north of Interstate 84.

The WSA’s goal is to have an expanded sewer system operational by this fall.

Fuss & O’Neill, Inc, is the town’s consulting engineer on the sewer expansion project. The firm was the town’s engineer for the original Hawleyville sewer system and for the central sewer system.

Unlike the original Hawleyville sewer system and the central system, which employ gravity-powered sewers augmented by sewage pumping stations, the Hawleyville sewer expansion project will employ low-pressure sewer lines.

The low-pressure design reduces sewer system construction costs by reducing the construction complexity.

With low-pressure sewers, sewer mains will only need to be buried several feet underground. In such a design, the need for expensive deep trenching and new sewage pumping stations is eliminated.

Several years ago, town officials had estimated it could cost up to $5 million to expand the Hawleyville sewer system using conventional gravity-powered sewers and a new pumping station.

In a low-pressure sewer system, grinder pumps are employed to grind and liquefy sewage, which is then sent in bursts through narrow-diameter service lines to narrow-diameter sewer mains.

Sewage from the expansion area would be sent to an existing sewage pumping station located at 164 Mt Pleasant Road. Sewage from the Hawleyville system is sent to a regional sewage treatment plant in Danbury.