Aqua pura

A classic design masks the industrial nature of a high-technology water-treatment plant.
August 11, 2010

The new Walter J. Sullivan Water Purification Facility in Cambridge, Mass., can easily be mistaken for a commercial or institutional building. Its brick-clad exterior incorporates such features as a clock tower, arched entrances, and windows that are reminiscent of Boston-area water facilities designed by classical architect H.H. Richardson.

The 54,000-sf plant, which is also the headquarters for the water department, was built on the site of the city's former 78-year-old plant, which was razed to make way for the new facility. Some elements of the old structure were saved — Greek entrance columns and a pediment, and cast stone medallions of the city and state seals, which were incorporated into the two-story lobby.

Cambridge's water system delivers an average of 15 million gallons per day to the city's 101,000 residents. The Sullivan plant was built at a cost of $56 million. An additional $15 million cost was incurred when the city needed to purchase water from the Massachusetts Water Resources Authority (at a cost of $17,000 a day) while the water treatment operation was off line for two-and-a-half years. The project required three Federal, five state, and three local permits.

Deputy City Manager Richard Rossi says the facility has generated hundreds of favorable comments from the public. "They can't believe a water treatment facility can look that good," he says. Boston Heraldarchitecture critic Robert Campbell, not an easy person to impress, also gave the facility a favorable review.

Putting out the welcome mat

Cambridge wanted a state-of-the-art, secure facility that could double as a public meeting place and educational resource. A room used for training water department employees doubles as a venue for public meetings. It accommodates more than 35 people; larger groups can spill into the adjacent lobby.

On the education front, the public is encouraged to come inside and view the treatment equipment and control room. Colored ceramic tiles throughout the facility were used to create large murals that outline the water treatment process flow.

Programmatically, the building takes in 34,500 sf for administration and operations, a laboratory, and vehicle storage and maintenance space.

Process areas within the building provide a working environment that is naturally lighted by a building-length skylight, says Barry Giorgi, project manager with the facility's designer, Cambridge-based consulting engineer CDM. Daylight filters through space frames that resemble trellises.

A 2,500-sf map in the lobby's terrazzo floor, financed through the city's 1%-for-public-art requirement, uses brass inlays to represent the routes of pipe running along Cambridge's 180-mile water main transmission and distribution system. It is the work of local artist Mags Harries.

An outside drinking fountain connected to an 11-foot-tall glass cylinder in the lobby provides a whimsical touch. When the fountain is activated, the cylinder lights up and compressed air makes the water inside it bubble up.

The Sullivan facility is adjacent to the 1.4 billion-gallon Fresh Pond Reservoir, from which the plant draws its water supply. The reservoir is the centerpiece of Fresh Pond Reservation, the city's largest open space. Due largely to advances in technology, the new 24-million-gallon-per-day plant occupies less than half the area of its predecessor, thereby freeing up more than three acres for public use (a new bike path is one benefit). The new plant also provides less of a visual barrier to views of Fresh Pond than its predecessor.

The former plant, with its outdoor settling basins, had to be enclosed by fencing. The Sullivan plant is all under roof and not marred by fencing.

The new facility was needed to meet water quality requirements that are increasingly difficult to achieve with old equipment, says Stephen Corda, managing director of the Cambridge Water Department.

The building's noteworthy aesthetics take a back seat to the high-tech nature of the facility, says Jeff Bardell, VP and area manager of the project's general contractor, Walsh Northeast, Sharon, Mass., a unit of Chicago-based Walsh Group, one of the nation's largest builders of water facilities. Veitas and Veitas Engineers of Braintree, Mass., served as the project's structural engineer.

Bardell says it is important to look beyond the structure's impressive architecture to its state-of-the-art operational capability. For example, a dissolved air flotation pre-treatment process, widely used in Europe but rare for the U.S., occupies only one-fifth as much area as the former plant's outdoor settling basins, thus contributing to the compactness of the Sullivan plant.

Processing tanks have a maximum depth of 30 feet below grade. Water flows through the plant via gravity. The process equipment was accommodated without exceeding Cambridge's general height restriction of 35 feet. Only the unoccupied tower above the main entrance and a clock tower that rises above a side entrance exceed this limit.