Protecting Water Purity of New York City’s Drinking Water 

New York City relies on a vast system of reservoirs, lakes and aqueducts to deliver more than 970 million gallons of water to their 9.6 million customers per day. Unfortunately, the Delaware Aqueduct, their primary water source is leaking approximately 20 million gallons per day and requires an 8-month shutdown to fix the leak. 

During the shutdown, New York City Department of Environmental Protection increased the supply from the Croton System to nearly 300 million gallons per day, or 30% of the city's water needs. Croton's mineral-rich water and seasonal changes often cause taste complaints. 

The Croton Lake Gatehouse Chlorine Dioxide Treatment System project installed a new pretreatment system within a historic gatehouse to reduce the taste and odor concerns while converting dissolved iron and manganese into solid, oxidized forms that can be filtered out. The new system controls biofilms, kills microbes instantaneously and eliminates the possibility of them developing immunity, and does not form trihalomethanes, an environmental pollutant. 

The system's fully automatic process maximizes and enhances operational system control and oversight capabilities while maintaining public health requirements and the high expectations of New York City residents. With limited space and a facility not designed for bulk chemical storage, the team modified the floor, added secondary containment systems and overhauled the HVAC. Delivered on budget and ahead of the required implementation date, the project transformed an underutilized structure into a vital piece of infrastructure that houses one of North America's largest chlorine dioxide systems.