The New York City (NYC) Department of Environmental Protection awarded a US$ 35.7-m contract to the joint venture team of Hazen & Sawyer and CDM for permitting, design and design services during construction for a two-billion-gallons/day potable water ultraviolet light (UV) disinfection facility.
The UV facility will disinfect unfiltered water from the Catskill and Delaware reservoir systems, which provide 90% of the drinking water used by nine million NYC customers. When complete in 2009, it will be the world's largest capacity plant for potable water, using the largest UV disinfecting units every built - each sized to handle 40- to 50-million gallons per day of water. The UV facility is estimated to cost approximately US$ 500 million, less than one-fourth the cost of a filtration plant.
This project represents a tremendous leap forward, allowing the city to use UV disinfection at an unprecedented scale, according to CDM, on an unfiltered supply to meet water quality requirements, including 2-log (99%) treatment of Cryptosporidium. Implemented under a Filtration Avoidance Determination schedule with the US Environmental Protection Agency, the project allows NYC to maintain its non-filtration status and precludes the need for a massive filtration facility.
Hazen & Sawyer is a NYC-based environmental engineering firm, and CDM is a global consulting, engineering, construction and operations firm based in Cambridge, Massachusetts, USA, that specialises in environmental and infrastructure projects.
