New York City Department of Environmental Protection: Croton Filtration Plant JANUARY 10 www. bus- ex. com 191 New York City's new Croton Filtration Plant will use modern technology to filter and treat hundreds of thousands of gallons of water every day. Keith Regan learns how the long- planned project will help the city meet a federal mandate with minimal impact on the community hosting the facility is now in the midst of a $ 2.2 billion construction project that will meet federal mandates and provide up to 290 million gallons of clean and filtered water to the City once completed in early 2012. . In times of peak drought, the Croton system- fed by reservoirs in Westchester County- can account for up to 30 percent of the City's water needs. The water has long been disinfected with chlorine, but agreements with regulators now require filtration as well, according to New York City Department of Environmental Protection ( DEP) executive construction manager Bernard Daly, P. E. The project includes not only $ 2.1 billion worth of O n an average day, the residents, businesses and infrastructure of the City of New York demand more than 1 billion gallons of water. On the hottest summer days, the metropolis can demand twice that amount. Quenching the city's thirst are three water sources: the Croton, Catskill and Delaware systems. By volume, the Croton water system is now the smallest and by age it's the oldest, with the water traveling to the city via aqueducts completed toward the end of the 19th century. After years of regulatory action and delays, the City

192 www. bus- ex. com JANUARY 10 construction costs at the Bronx site but another $ 100 million in off- site work for upgrades at Jerome Park Reservoir and another $ 20 million contract to connect a force main to Hunts Point WPCP. The project will be decades in the making by the time it's completed in 2012, a significant portion of that time spent dealing with legal challenges and neighborhood opposition to the project. " It was a facility that some individuals and community groups did not want in their backyard," Daly says. For many years DEP has been under orders to build a filtration plant for the Croton system, but siting required years of permitting work and eventually the vote of the state legislature to turn parkland over for the project. The siting hurdle was overcome in large part thanks to a unique design that will result in the plant sitting underground, topped by a driving range and clubhouse for an existing nine- hole golf course. Plans call for that clubhouse to be LEED certified for sustainability. In addition, the residuals from filtration plant will be disposed of at an existing wastewater pollution control plant located about 7.5 miles away, a design tweak that enabled the footprint of the plant to be reduced. Daly and executive project manager Arne Fareth, P. E., lead a team representing the DEP on the project, which currently has 14 active contracts. The work is also being closely watched by the US Environmental Protection Agency ( EPA), New York State Attorney General's Office and New York State Department of Health. The plant will receive water from the reservoirs in the system and then put it through a process train that starts with mixing and flocculation, then a stacked dissolved air flotation and filtration process, and then ultraviolet disinfection, which is gaining favor over chlorination as a water treatment methodology. Placing the plant underneath the driving range meant that 186,000 cubic yards of soil and 920,000 cubic yards of rock had to be removed, most of the rock requiring blasting. Excavation work on the site lasted more than two years and was done with a number of mitigation measures put in place to address neighborhood concerns, such as designated truck routes, active dust control, noise abatement and retrofitting of onsite diesel- powered equipment to meet the latest EPA emission standards. The plant's site, in Van Cortlandt Park, is bound by the Mosholu Parkway and the Major Deegan Expressway on two sides, by a local Bronx road and the Woodland Station of the Interborough Rapid Transit ( IRT) No. 4 elevated subway. Actual plant construction began in the summer of 2007 with concrete placement and large- diameter pipe installation, and it is expected to accelerate in pace during 2010. Managing the sheer size and scope of the project requires a full toolbox that includes constant contact with contractors and coordination among more than a dozen contracts, as well as interaction with the regulatory authorities. " This is a high- profile job that is attracting a lot of attention," Fareth says. " We spend a lot of time focusing on schedule, quality and site safety and emphasizing those issues to the contractors who are responsible for making sure their subcontractors are complying."