The second aspect of $48-million renovation of the town’s sewer system — closing of the District Two sewage treatment plant off Route 7, and construction of a pumping station and pipeline to get that wastewater to the District One plant off South Street — will come up for comment at the end of the month.

A public hearing on the project has been scheduled for Tuesday, Sept. 24, at 7:30 in the town hall annex. The hearing will be before the Planning and Zoning Commission, which approved the first phase of the project — upgrading the District One sewer plant off South Street — in late May.

“The Town of Ridgefield operates two wastewater treatment facilities (WWTFs), the South Street WWTF which serves Sewer District One and the Route 7 WWTF which serves Sewer District Two,” says a cover letter on the application from Jon Pearson of AECOM, the sewer engineering firm working with the town.

“The Water Pollution Control Authority will be upgrading the wastewater facilities in order to improve the condition of aging infrastructure and address the treatment requirements in the National Pollutant Discharge Elimination System (NPDES) permits for the WWTFs from the Connecticut Department of Energy and Environmental Protection (DEEP)...

“To address these needs, the WPCA completed a two-phase wastewater facilities plan study, which recommended a number of upgrades to the existing wastewater facilities.”

There are two phases to the project.

“Under the first construction contract the South Street wastewater treatment facility will be upgraded to rehabilitate or replace existing facilities and systems, and to provide new treatment systems and structures.”

This is the project approved in May.

“Under the second contract the existing Route 7 WWTF will be demolished and a new force main and replacement pump station will be constructed to convey the District Two wastewater flows that are currently directed to the Route 7 WWTF to the South Street WWTF.”

“The existing Route 7 pump station will be completely demolished and a new pump station will be constructed in the same location,” the letter from AECOM’s Pearson says.

Pipeline

“...The Sewer District Two flows that were previously conveyed from the existing pump station to the Route 7 WWTF will be conveyed to the South Street WWTF through a new 14,150-foot-long, eight-inch diameter force main,” the sewer engineers say. “The route of the force main will be along Route 7 to Haviland Road, to Limekiln Road, to Lee Road, to Farmigville Road, to Ligi’s Way, and finally to South Street.”

The pipe’s path south on Route 7 will be repaved for half the highway’s width, and the local roads will be completely repaved along the route.

The project involves “demolition and removal” of structures above ground and also “all below grade structures to three feet below grade” as well as removal of all pavement, with those areas planted with grass.

A schedule for the project envisions it going out to bid in the fall of 2020, and construction running from January 2021 to March 2022.

Concerns

Highlighting “specific concerns and issues” the letter from AECOM notes that “temporary pumping and power systems” will be required during demolition and reconstruction of the pump station.

There will also be an effort to limit the “visual impacts” of the new pump station.

“The existing Route 7 pump station is mostly out of sight” with many facilities below grade, Pearson says.

“However, due to the new resiliency standards adopted by DEEP, a number of the replacement structures will be located above grade to an elevation of three feet above the FEMA 100-year floor elevation.”

Steps planned to limit the visual impact include a green vinyl fence on three sides — the east side facing Route 7 and the adjacent north and south sides of the pump station — to create a “visual barrier.” There will also be “an earthen berm/mound, visual barrier plantings” and “ornamental plantings” on the east side, shielding view of the pump station from Route 7.

Pearson of AECOM also says that “after consultation with the owners of the adjacent land parcel at 901 Ethan Allen Highway, and with all parties in agreement, the project proposed to narrow the 901 Ethan Allen driveway … to provide additional land between the pump station parcel and 901 Ethan Allen Highway,” giving the private property owner room for “future landscape plantings” to create “an improved visual barrier to the pump station without impacting the access to the pump station.”