Town of Halfmoon Water Treatment Facility

A new 2.0-mgd water treatment facility that opened in August has provided a big boost to the Town of Halfmoon, N.Y., a fast-growing residential and commercial hub about 300 miles north of New York City.

The town, which had been purchasing water from a neighboring community, decided to meet its long-term water supply needs by building a new facility.

The project team responded with plans for a $10.3 million facility using new treatment technology that promotes faster sedimentation of water with highly variable turbidity-just right for the chosen Hudson River source. The facility also features a raw intake and pump system, five chemical feed systems, on-site sludge and backwash disposal, and a water storage facility.

First up, the project team had to select the water source - from the Tomhannock Reservoir, the Mohawk River or the Hudson. It weighed potential problems such as high mineral content and inactive hazardous waste sites at the reservoir and Mohawk against the Hudson's contamination with polychlorinated biphenyls and its upriver discharge from industrial operations and wastewater treatment plants.

The team eventually chose the Hudson because of its ample capacity for drawing water over the long term. The project team launched a careful investigation and analysis that incorporated input from various regulatory agencies, a close understanding of the interplay with a regional canal system and the need to convince Halfmoon residents that the Hudson was the best choice.

The team then helped the town secure more than 15 permits or approvals from agencies such as the U.S. Environmental Protection Agency, the Army Corps of Engineers, the U.S. Coast Guard, the state departments of health and environmental conservation and even the New York State Thruway Authority. The team navigated through some approvals by using pre-permit application meetings and conference calls to build early consensus and identify relevant issues prior to final design and construction.

With an overall fast-track schedule, the project players-including six prime contractors and more than 50 minor subcontractors, suppliers and equipment manufacturers-used a team-oriented attitude and concentrated communication to ensure success.

At the design and construction phase, the team first had to acquire two parcels and eight easements for the facility and infrastructure. Then it had to ensure the river bottom near the site was deep enough to provide sufficient raw water intake.

The team scheduled dredging between November and April in order to avoid interrupting river shipping and boating activities. That also required a tight review time frame with regulatory agencies.

Once construction began, the team had to make adjustments for high water levels in the river during parts of 2002. The team also met a project goal to quickly complete the exterior of facility buildings, which enabled the general, plumbing, HVAC and electrical contractors to work indoors during the winter.

In the end, the project came in under budget and is supplying drinking water that meets state Department of Health standards. "This project looks like it was similar to tuning a watch," one jury member said. "The politics and processes were very challenging."

The facility now operates using an advanced automated SCADA system, which turns on pumps, opens valves and detects alarm conditions based on the town's needs. The town also has the capability to double the plant's capacity in the future.