NORTHBRIDGE — In the midst of a federal and state push toward the greening of America, Alternatives has just cleared trees and brush along the Mumford River to prepare for installation of a turbine this summer to recapture the stream’s energy.

Alternatives may seem an unlikely source of rehabilitation of an 1826 mill, because its major task is to care for some 550 people with developmental and psychiatric disabilities through 45 residential and employment programs across Central Massachusetts.

Alternatives Executive Director Dennis Rice understands the surprise. He acknowledges as unexpected the “new paradigm” of a human service agency taking on a project like the restoration of an old textile mill. But he explains it as an engagement of the community to build a stronger Northbridge.

The variety of pieces in the puzzle that has comprised the new version of the mill complex that once served as the Whitinsville Spinning Ring Company and before that as the original core of the 135-year Whitin enterprise is not only surprising, but transformational.

Buildings that have at best been picturesque are being turned into vibrant new uses even as the historic is preserved and honored.

The mill restoration project has been going on now across a span of four years and the new is as marked as the old revived.

In its efforts to create a closer connection between its own mission and that of the community at large, Alternatives has combined historical and educational aspects within its approximately $10 million renovation.

Moreover, the makeover of the historic industrial complex includes creation of a riverfront community plaza, space for local artists, apartments for six clients, and a performance center. A restaurant may be included as the economy improves.

The project also includes a renewable energy system combining solar, geothermal and waterpower. As soon as the hydroelectric turbine is put in place, the complex is expected to become 90-percent self-reliant in energy.

Philip Ingersoll-Mahoney, director of administration and finance for Alternatives, explained that the Mumford River within the 600-foot long stretch before the dam opposite the 1826 Brick Mill will be raised nearly 30 inches to boost the water pressure entering the turbine.

Tom Saupé, director of community relations, pointed to a gray area on granite blocks under the gate controls on the Town Hall side of the river. “You can see how high the river was when the dam was operativein the early Whitin era,” said Saupé.

It is to that same height Alternatives plans to raise the water level above the new turbine, regaining the same weight of water as once drove the machinery that made Whitin the dominant producer of textile preparatory machinery in the world.

Ingersoll-Mahoney explained the new turbine has an intake, or headrace, funnel about 36 inches in diameter and sloped at about 45 degrees. At the other end of the turbine is the tailrace where the spent water flows back into the river.

“It will produce about 365,000 kilowatts a year,” he said. The energy not used will go into the National Grid and Alternatives’ energy bill will be reduced by as much energy as it contributes to the grid.

“We also have a geothermal system of heating and cooling,” he explained. “It involves five 1,500-foot-deep wells under the Alternatives parking lot and plaza.”

The wells use the constant 55- degree temperature at that depth to ensure seasonal climate control.

“Every room has a heat exchange unit,” Rice explained. “It’s basically just a matter of circulating the water.”

Ingersoll-Mahoney said the cost of installing the energy system should pay for itself in about three years.

The trees along the Mumford within the 600-foot length had to be removed [last weekend] when ice was on the river and the banks were frozen,” he explained. That was a requirement imposed by the Conservation Commission.

“They didn’t want any silt getting into the river,” he said. Tree removal requires heavy machinery, and that was not permitted while the banks were still soft. Additionally, the trees or shrubs that had their roots in the water had to be left alone, Ingersoll-Mahoney explained another of the commission’s strictures.

“The goal was to disturb the river banking as little as possible,” he said.

As Rice has explained, so Ingersoll-Mahoney noted, a workshop program Alternatives ran for its clients from back in the 1970s turned out to be just a different kind of confinement after they had been removed from state hospitals with the goal of becoming integrated into the community. Now they are not isolated, but live and work throughout the region. Alternatives monitors their well being.

Along with the turbine, new flashboards will be put into place this summer along the top of the current dam.

Already in place are 32 photovoltaic panels on the administration building roof that provide some 5 percent of Alternative’s energy needs.

Health administrators from Europe and elsewhere have visited Alternatives to learn about the integration of human services with historical and environmental preservation.