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Advancing Large-Scale Drinking Water Treatment

new york city department of environmental protection NEW YORK CITY, USA
The largest of its kind in the world, with a design capacity of 2 billion gallons per day, the innovative Catskill-Delaware facility treats nearly 90 percent of New York City's drinking water.

Part of the world’s largest unfiltered surface supply, the Catskill-Delaware system conveys water from an expansive watershed in upstate New York through dozens of miles of tunnels to Kensico Reservoir, approx­i­mately 12 miles north of New York City in Westchester County. Here, the Catskill-Delaware ultraviolet (UV) disin­fec­tion facility applies enhanced disin­fec­tion of the drinking water supply for nearly 9 million New York City and upstate residents—setting a new standard in UV technology.

Completed by a joint venture team led by CDM Smith and Hazen and Sawyer, the facility has been fully operational and treating the entire flow from the Catskill-Delaware supply since December 2012.

%
of the NYC drinking water supply treated by this facility
residents served by this facility
%
energy savings from the LPHO UV technology vs. the alternative

Setting the Standard
Due to the watershed’s high-quality water, the New York City Department of Environmental Protection (NYCDEP), with the joint venture’s help, obtained a filtration waiver from the U.S. Environmental Protection Agency (EPA). However, changing regulations for unfiltered surface water systems require enhanced disinfection to inactivate Cryptosporidium (an organism that can cause gastrointestinal illness), and NYCDEP sought alternatives to compliance that would not require a costly filtration plant.

Studies showed that enhanced disinfection with UV would provide at least equivalent protection for the city’s water supply at a much lower cost than filtration. “This project demonstrates that UV technology is both a feasible and cost-effective disinfection alternative for large-scale potable water facilities,” observes Brian Kearney, CDM Smith project manager. Previously, UV systems in the United States were limited to wastewater treatment and much smaller drinking water projects.

The Catskill-Delaware facility applies low-pressure, high-output (LPHO) UV disinfection technology on a scale that is unmatched. “The size and capacity of the facility sets Catskill-Delaware apart," says Kearney. “It includes four 12-foot diameter raw water pipes, 11,760 lamps in fifty-six 48-inch diameter UV vessels, and the four 144- by 120-inch venturi flow meters.” The facility also uses sixteen 84-inch-diameter, inline, space-efficient energy dissipation valves—the largest ever built—to control flow through the plant.

Sustainable Approaches
Using UV disin­fec­tion rather than filtration resulted in significant savings. The $1.3 billion Catskill-Delaware facility costs consid­er­ably less than the expense of building and operating a filtration plant.

A holistic approach to design and construc­tion further reduced costs and minimized impacts on the environment. For example, the LPHO lamp technology requires 30 percent less power than the alternative, medium-pressure lamps, reducing energy use and lowering costs. Addi­tion­ally, the design was carefully developed to maintain gravity flow to the city, avoiding the need for large pumps and associated power use.

Throughout the project, the team carefully limited the facility footprint and construc­tion duration. The surrounding natural areas were also retained and enhanced through extensive wetlands mitigation and visual enhance­ments at Kensico Reservoir in the town of Mount Pleasant. From start to finish, measures were taken to protect air quality and reduce the facility’s carbon footprint, including using low-sulfur fuels in construc­tion equipment.


Setting the Standard
Due to the watershed’s high-quality water, the New York City Department of Envi­ron­men­tal Protection (NYCDEP), with the joint venture’s help, obtained a filtration waiver from the U.S. Envi­ron­men­tal Protection Agency (EPA). However, changing regulations for unfiltered surface water systems require enhanced disin­fec­tion to inactivate Cryp­tosporid­ium (an organism that can cause gastroin­testi­nal illness), and NYCDEP sought alter­na­tives to compliance that would not require a costly filtration plant.

Studies showed that enhanced disin­fec­tion with UV would provide at least equivalent protection for the city’s water supply at a much lower cost than filtration. “This project demon­strates that UV technology is both a feasible and cost-effective disin­fec­tion alternative for large-scale potable water facilities,” observes Brian Kearney, CDM Smith project manager. Previously, UV systems in the United States were limited to wastewater treatment and much smaller drinking water projects.

The Catskill-Delaware facility applies low-pressure, high-output (LPHO) UV disin­fec­tion technology on a scale that is unmatched. “The size and capacity of the facility sets Catskill-Delaware apart," says Kearney. “It includes four 12-foot diameter raw water pipes, 11,760 lamps in fifty-six 48-inch diameter UV vessels, and the four 144- by 120-inch venturi flow meters.” The facility also uses sixteen 84-inch-diameter, inline, space-efficient energy dissipation valves—the largest ever built—to control flow through the plant.

 

Setting the Standard
Due to the watershed’s high-quality water, the New York City Department of Envi­ron­men­tal Protection (NYCDEP), with the joint venture’s help, obtained a filtration waiver from the U.S. Envi­ron­men­tal Protection Agency (EPA). However, changing regulations for unfiltered surface water systems require enhanced disin­fec­tion to inactivate Cryp­tosporid­ium (an organism that can cause gastroin­testi­nal illness), and NYCDEP sought alter­na­tives to compliance that would not require a costly filtration plant.

Studies showed that enhanced disin­fec­tion with UV would provide at least equivalent protection for the city’s water supply at a much lower cost than filtration. “This project demon­strates that UV technology is both a feasible and cost-effective disin­fec­tion alternative for large-scale potable water facilities,” observes Brian Kearney, CDM Smith project manager. Previously, UV systems in the United States were limited to wastewater treatment and much smaller drinking water projects.

The Catskill-Delaware facility applies low-pressure, high-output (LPHO) UV disin­fec­tion technology on a scale that is unmatched. “The size and capacity of the facility sets Catskill-Delaware apart," says Kearney. “It includes four 12-foot diameter raw water pipes, 11,760 lamps in fifty-six 48-inch diameter UV vessels, and the four 144- by 120-inch venturi flow meters.” The facility also uses sixteen 84-inch-diameter, inline, space-efficient energy dissipation valves—the largest ever built—to control flow through the plant.

 

Setting the Standard
Due to the watershed’s high-quality water, the New York City Department of Envi­ron­men­tal Protection (NYCDEP), with the joint venture’s help, obtained a filtration waiver from the U.S. Envi­ron­men­tal Protection Agency (EPA). However, changing regulations for unfiltered surface water systems require enhanced disin­fec­tion to inactivate Cryp­tosporid­ium (an organism that can cause gastroin­testi­nal illness), and NYCDEP sought alter­na­tives to compliance that would not require a costly filtration plant.

Studies showed that enhanced disin­fec­tion with UV would provide at least equivalent protection for the city’s water supply at a much lower cost than filtration. “This project demon­strates that UV technology is both a feasible and cost-effective disin­fec­tion alternative for large-scale potable water facilities,” observes Brian Kearney, CDM Smith project manager. Previously, UV systems in the United States were limited to wastewater treatment and much smaller drinking water projects.

The Catskill-Delaware facility applies low-pressure, high-output (LPHO) UV disin­fec­tion technology on a scale that is unmatched. “The size and capacity of the facility sets Catskill-Delaware apart," says Kearney. “It includes four 12-foot diameter raw water pipes, 11,760 lamps in fifty-six 48-inch diameter UV vessels, and the four 144- by 120-inch venturi flow meters.” The facility also uses sixteen 84-inch-diameter, inline, space-efficient energy dissipation valves—the largest ever built—to control flow through the plant.

 

Setting the Standard
Due to the watershed’s high-quality water, the New York City Department of Envi­ron­men­tal Protection (NYCDEP), with the joint venture’s help, obtained a filtration waiver from the U.S. Envi­ron­men­tal Protection Agency (EPA). However, changing regulations for unfiltered surface water systems require enhanced disin­fec­tion to inactivate Cryp­tosporid­ium (an organism that can cause gastroin­testi­nal illness), and NYCDEP sought alter­na­tives to compliance that would not require a costly filtration plant.

Studies showed that enhanced disin­fec­tion with UV would provide at least equivalent protection for the city’s water supply at a much lower cost than filtration. “This project demon­strates that UV technology is both a feasible and cost-effective disin­fec­tion alternative for large-scale potable water facilities,” observes Brian Kearney, CDM Smith project manager. Previously, UV systems in the United States were limited to wastewater treatment and much smaller drinking water projects.

The Catskill-Delaware facility applies low-pressure, high-output (LPHO) UV disin­fec­tion technology on a scale that is unmatched. “The size and capacity of the facility sets Catskill-Delaware apart," says Kearney. “It includes four 12-foot diameter raw water pipes, 11,760 lamps in fifty-six 48-inch diameter UV vessels, and the four 144- by 120-inch venturi flow meters.” The facility also uses sixteen 84-inch-diameter, inline, space-efficient energy dissipation valves—the largest ever built—to control flow through the plant.

 
The size and capacity of the facility sets Catskill-Delaware apart.
Brian kearney, project manager

Designing for the Future
The Catskill-Delaware project team faced numerous challenges, which included selecting the UV system supplier and demon­strat­ing the necessary Crypto log inac­ti­va­tion while the design was ongoing. Meanwhile, to meet the aggressive schedule set forth in the city’s filtration avoidance deter­mi­na­tion with the EPA, staged construc­tion was used, including a site preparation contract that advanced more than 600,000 cubic yards of mass excavation while the facility’s design was being completed. The UV facility construc­tion was completed on schedule and on budget—meeting the multiple interim milestones established by regulators.

Quality control was ensured using a 3D model of the designed facility, identifying potential conflicts during the early stages of construc­tion that enabled timely action to resolve issues and complete the project on schedule. In addition, 4D modeling used by the general contractor integrated a schedule component to more efficiently sequence work activities across the site. The facility’s innovative design also allows for a future, 2-billion-gallon-per-day filtration plant to be built on the same site if necessary, while maintaining gravity flow and avoiding energy-intensive, costly pumping. It provides a separate UV treatment system for the host community, and a connection for future UV treated water by neighboring communities.

Imple­ment­ing UV at Catskill-Delaware advances the application of this technology across the industry, and sets an example in sustainable infra­struc­ture. The facility maintains the city’s legacy for providing safe, clean water to its consumers in an energy-efficient and envi­ron­men­tally responsible way.

Project Details

Defining water supply innovation 
This project spearheaded the UV disinfection revolution for drinking water facilities, leading to widespread use around the country.

2013 ENR Best of the Best: Water/Environment
This project was named Engineering News-Record's Best of the Best in 2013 in the Water/Environment category. In addition, this project was named the 2013 UV Engineering Project of the Year by the International Ultraviolet Association, the 2013 Project of the Year by the Municipal Engineers of New York, and recieved a 2013 National Grand Engineering Excellence Award from the American Council of Engineering Companies.

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