Catskill–Delaware Ultraviolet Water Treatment Facility, New York, United States of America
Catskill-Delaware Ultraviolet Water Treatment Facility, which came online in October 2013, is the biggest ultraviolet (UV) disinfection facility in the world.
It is located downstream of Kensico Reservoir within the towns of Mount Pleasant and Greenburgh in Westchester County. It has a water treatment capacity of 2.24 billion gallons a day (BGD).
The New York City Department of Environmental Protection owns the plant. Planning activities for the project commenced in 2002, construction commenced in 2006 and the initial treatment activity began in 2012. Total construction cost reached $1.5bn.
The facility serves more than nine million people in New York and created approximately 740 construction jobs and 40 permanent jobs.
The project won the 2013 Best New York Region Project Award, from Engineering News-Record (ENR), in the water / environment category. It also won the UV Engineering Project of the Year Award from International Ultraviolet Association (IUVA) in October 2013.
Catskill-Delaware water treatment project background
The new UV water treatment project is a result of the precautionary measures adopted by the City of New York following the outbreaks of Cryptosporidium and Giardia-related illnesses in other parts of the US.
It was also constructed to meet the requirements of the Environmental Protection Agency's (EPA) Long Term 2 Enhanced Surface Water Treatment Rule in Westchester County.
A filtration plant estimated at $8bn was proposed initially, but the plan was later changed to building a UV facility, resulting in substantial savings. The design of the treatment plant provides an option for a two billion gallon-per-day filtration plant to be built on the same site in future.
The Catskill and Delaware watersheds supply 90% of the city's drinking water. The two watersheds, along with the Croton watershed, extend for more than 200km, incorporating 19 reservoirs and three controlled lakes.
Construction of the world's largest UV disinfection facility
The water disinfection facility covers approximately 160,000 square feet. The above-ground portion of the building is constructed of structural steel with a precast facade, while the roof of the main building is constructed of stainless-steel.
Security measures that went into the plant's design included electronic access and monitoring systems, gate and fence systems to create stand-off areas and creating a blast resistant structure.
The construction works involved 1.3 million square feet of foundation works, installation of 10,000ft of stainless steel pipe, more than a mile of field-cement-lined 12ft-diameter pipes, 1,200t of structural steel, 20,000 square feet of aluminium grating and pouring of 121,000 cubic yards of concrete.
Electricity is supplied to the plant via two 13,000V feeder lines incorporating backup generation system. The project also included improvements to the existing Delaware Aqueduct.
Treatment technology at the Catskill-Delaware UV disinfection plant
The plant applies low-pressure, high-output (LPHO) UV disinfection technology, which requires 30% less power than the alternative, medium-pressure lamps.
It features 56 TrojanUVTorrent units consisting of stainless steel disinfection chambers featuring 11,760 UV lamps immersed in the water flow. Each unit is capable of processing 40 million gallons of water. The UV vessels measure 48 inches in diameter.
Other treatment equipment includes four 12ft diameter raw water pipes and four 144in x 120in venturi flow meters. The facility also integrates 16 84-in-diameter energy dissipation valves to control flow throughout the plant.
The treatment process involves screening, UV treatment and chlorination. The treated water is conveyed to the existing Delaware Catskill aqueducts through gravity before being supplied to the consumers.
Key players involved with the Catskill-Delaware water treatment plant
The plant was constructed by a joint venture (JV) of Skanska USA Civil, ECCO III and JF White. CH2M HILL, in partnership with Arcadis, was the construction manager. The planning, design and construction services were provided by a joint venture comprising of CDM Smith and Hazen and Sawyer. Dattner Architects provided the plant design, while the electrical works were carried out by Welsback Electric and the plumbing & HVAC works by LJ Coppola.
Construction of the new Brightwater WWTP, which began with preliminary demolition and clearance work on the 114 acre site in November 2005, was originally scheduled to enter service in 2010.
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