Hazen and Sawyer Wins Platinum Award in 2008 Engineering Excellence Awards Competition

Stamford Water Treatment Plant Benefits Community with Innovative, Environmentally-Friendly Design

(NEW YORK, NY- January 16, 2009) – The Stamford Water Treatment Plant (WTP) Upgrade and Expansion Project won the Platinum Award from the American Council of Engineering Companies (NY), the second highest honor in the 2008 Engineering Excellence Awards program.

The Aquarion Water Company of Connecticut, owner and operator of the Stamford WTP, commissioned Hazen and Sawyer to undertake the project, involving upgrade and expansion of the existing 24-mgd facility to a capacity of 30 mgd, as needed to meet both increasing demands imposted by population growth and more stringent water quality standards. As the sole source of Stamford’s drinking water, it was imperative that the existing plant remain in operation during the construction.

The Stamford WTP is in close proximity to a residential neighborhood, leading Hazen and Sawyer to incorporate innovative design elements that reduced visual, noise, and other construction impacts. A focus on sustainable features will benefit the community for years to come, including:

  • Optimal use of existing facilities – Initially, only the existing chemical system, control room, laboratory, and administrative offices were considered for reuse. However, by retaining the existing raw water pumping station, clearwell, and high service pumps with only minor improvements, the plant footprint was reduced by ~ 36,000 square feet, significantly lowering construction costs.
  • Efficient Design of New Facility – Waste washwater and filter-to-waste were combined. Solids produced during these processes were recycled to the head of the plant instead of removing them through settling, thus eliminating the need for additional equipment.
  • Reducing Power Consumption – Open channel static mixers (which do not require power) were used for rapid dispersion of coagulants and other chemicals, eliminating the need for energy intensive rapid mixers. The plant elevation was also raised 15 feet, enabling the plant to treat higher flows using gravity, reducing raw water pumping costs.
  • Reducing Visual Impacts – Centrifuges were initially considered for solids dewatering. However, permission was granted for Stamford Department of Public Works to dispose of residuals in the city sewers, a much more cost-effective solution. The elimination of this solids handling equipment reduced the height of the new building by two feet.
  • Avoiding Environmentally-Sensitive Areas – Two new 2.2-million gallon steel storage tanks were constructed to increase treated water storage, afford additional disinfection contact time, and provide higher pressure to the gravity distribution system. The location of the tanks was carefully selected to prevent encroachment on existing wetlands and blend into existing topography. The color of the tanks was selected by the community to blend well with the surroundings.

The project resulted in an expanded, 30-mgd WTP that produces high-quality drinking water at higher pressures. Placed in service in 2007, the expanded plant occupies less area than the original facility, and better serves Aquarion’s customers in the Stamford area.

For more than half a century, Hazen and Sawyer has focused on two things: providing safe drinking water and controlling water pollution. Our range of services encompasses the planning, design, and construction management of water and wastewater-related projects – from clean water treatment, storage, and distribution to wastewater collection and treatment. Since our founding in 1951, we have grown in size to over 740 employees in 25 offices.

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