Old Lyme - Treating wastewater in town could be a viable option that costs about as much as transporting wastewater through sewer pipes to New London, according to recent results from a town-commissioned study.

The Water Pollution Control Authority is weighing the pros and cons, such as environmental pollution, for both local and regional options. The authority will likely vote on an initial option to further study at next month's meeting, said Chairman Kurt Zemba.

The state Department of Energy and Environmental Protection has ordered Old Lyme Shores Beach Association and Old Colony Beach Club Association to hook up to sewers by 2016. The two chartered beach communities have studies showing their on-site individual septic tanks are polluting the groundwater. The shoreline area tends to face shallow groundwater and smaller lot sizes.

The town's feasibility study, conducted by the engineering firm Woodard & Curran, states that connecting to sewers would be easier to implement initially and require fewer permitting steps, but a local system would allow the town to have long-term control over its capital, wastewater capacity and water balance, according to summary results.

A local facility would amount to $63,403,000 in total capital costs, while a regional option would cost $62,054,000, according to preliminary estimates. The annual cost per unit would be $2,580 for the local option and $2,640 for the regional one, assuming a 25 percent grant and 2 percent interest rate, the table showed.

A local wastewater facility would also call for agreements for the use of land, but soil testing at two sites in town from the study showed a facility would be feasible, he said.

The facility could be built as a small enclosed structure with a holding tank underneath on roughly 3 acres of land, according to Zemba. The facility would separate the wastewater into liquid, the largest component, and solid waste.

The facility would treat the liquid so it becomes potable water to flow into the land and waterways, he said. The solid waste could be reused, for example, by a company that would pay to use it as fertilizer. Using treated wastewater to irrigate land is another possible option, he added. The technology could include UV disinfection and a membrane bioreactor for filtration, according to a Woodard & Curran presentation this summer.

The regional option is to connect individual homes to sewer pipes along Route 156 through East Lyme and Waterford to reach the sewer plant in New London, which the Point O'Woods Beach Association has already done.

The communities would need to sign agreements with the towns for sewage to pass through the towns, he said. DEEP ultimately determines the capacity of the New London facility.

After the WPCA reaches an initial decision, town officials would gather more information on the system to bring to a public meeting for comment. The town would also need to determine state support for the program, how to collect the wastewater - such as what kind of pipe to use - and which areas in town would want to use the system, he said.

After further planning from the Board of Selectmen and Board of Finance, residents would eventually vote on funding a proposed option, said Zemba.

If the town proceeds with the local option, Zemba said Old Lyme would be the first in the state to implement the technology, which other New England communities use. The town would seek grants to help fund the system and would charge user fees, he said.

"It would be groundbreaking for Connecticut," he said. "It would really bring Connecticut into the 21st century."

The WPCA discussed the study at last week's meeting and will hold its next meeting on Oct. 8, which the Board of Selectmen will also attend.

k.drelich@theday.com