The 30-foot high "bio-tower" being completed at Farmington's wastewater treatment facility is the most visible sign of the doubling of this complex's capacity over the past five years.

But the effect of this expansion and upgrade goes well beyond the site.

The project gives the treatment facility a capacity of processing 4 million gallons of sewage and wastewater a day. As a result of the upgrades, purer treated sewage is being discharged into Mud Creek and odor emission is being decreased.

And with an $18 million price tag, the project is the biggest town expenditure on a project in Farmington history. "It promotes economic development - as much as roads," said Supervisor Ted Fafinski.

Farmington built its wastewater treatment plant about 45 years ago on 12 acres of land located on the west side of McMahon Road in east Victor. About 5,000 businesses - including those at Eastview Mall - and households in much of Farmington, Victor and a small part of the town of Canandaigua have their wastewater and sewage treated at the facility, said Jim Crane, water and sewer treatment superintendent for Farmington.

With better filters and other upgrades, the wastewater discharged into Mud Creek is about 98 percent pure, Crane said.

A low-interest loan from the state-created Environmental Facilities Corp. helped finance the project. Bonds to be repaid over 20 years were issued.

Annual sewer bills went up $20 for Victor and $28 for Farmington residents last January to help finance the expansion and upgrade.

An agreement between Farmington and Victor will result in sewer bills going up the same amount in the future. The latest increase was complicated by Farmington's taking over the sewage billing for Victor residents hooked up to the Farmington system. The bill for Victor residents no longer includes an $8-a-year charge to handle Victor billing costs.

Currently, households in the Farmington system pay $260 a year for sewer service, with the charge to businesses depending on the number of employees. Crane expects to ask the town to authorize another $20 a year increase for next year.

Crane said that when the facility was built, it could handle about 1 million gallons of sewage and wastewater a day with the one bio-tower, which is a concrete structure where a wastewater is cleansed by bacterial actions and filters. Capacity was doubled in 1990, with the addition of a second bio-tower.

Three more towers, including this most recent, have been added over the past five years after officials realized they were approaching capacity.

Crane expects that if growth continues at current rate, Farmington will have to look again at capacity in about 15 years.