New York City is home to more than eight million people, making it the most populous city in the United States. The City draws its drinking water from two protected surface water systems: the Catskill/Delaware and Croton watersheds. Historically, NYC has not filtered the water from this system nor did they require any additional barriers to microbial contaminants due to the pristine nature of the watershed.
In 2006, the United States Environmental Protection Agency released the Long Term Enhanced Surface Water Treatment Rule (LT2ESWTR). This new rule requires surface water treatment facilities to either filter their water or install an additional barrier for microrganisms as a multi-barrier disinfection strategy.
Engineers working on the Catskill/Delaware project evaluated a new filtration plant but the cost of installing a 2.2 billion gallon per day (BGD) filtration facility was significantly greater than other alternatives. After evaluation of available technologies, it was decided that UV was the most practical and cost-effective solution.
After evaluation of available lamp technologies, NYC chose to design a low pressure, high output (LPHO) lamp based UV system over a medium pressure (MP) lamp-based system. The LPHO units are capable of disinfecting the water utilizing approximately one-third the power of MP lamp units. Trojan Technologies offered a high-flow capacity LPHO lamp solution – the TrojanUVTorrent™ – which minimizes electrical costs while maximizing disinfection efficiency.
In separate work, Trojan assessed the relative carbon dioxide (CO2) emissions associated with both MP and LPHO solutions through a joint project with the University of Western Ontario. It was estimated that for the Catskill/Delaware Facility, the low pressure solution would lead to the release of approximately 13,700 fewer tons of carbon dioxide (CO2) annually than a medium pressure option (assuming that for typical conditions, the system operates at 70% of its peak capacity). Over 20 years, this equates to 274,000 fewer tons of carbon dioxide, making the TrojanUVTorrent™ the most environmentally-friendly solution for NYC.
CATSKILL/DELAWARE UV FACILITY
In 2005, Trojan Technologies was selected as the manufacturer for the UV portion of NYC drinking water project. In 2009 and 2010, Trojan delivered 56 TrojanUVTorrent™ UV units to the Catskill/Delaware UV Facility. Each unit is capable of delivering a 40 mJ/cm2 dose to 40 million gallons of water per day (MGD). This disinfection requirement, set by the NYC Department of Environmental Protection, delivers greater than 3-log reduction of microorganisms such as Cryptosporidium and Giardia. The TrojanUVTorrent™ was custom-designed by Trojan’s engineers and scientists in order to meet the challenging design parameters of this unique project.
CROTON WATER TREATMENT FACILITY
In 2006, Trojan Technologies was selected to supply the UV equipment for the new Croton Water Treatment Facility. This facility has the capacity to treat up to 600 MGD of high quality drinking water. Trojan is supplying 20 TrojanUVTorrent™ UV units. Each unit is capable of producing a dose of 40 mJ/cm2 to treat a flow of 30 MGD.
When completed in 2012, the Catskill/Delaware and Croton water plants will supply residents of NYC with over 2.8 BGD of high quality drinking water.