New York City's Wastewater Treatment System

Environmental Concerns

DEP manages a comprehensive range of programs to address many of the most pressing concerns that threaten our water environment. Following are program summaries.

Toxic substances

Heavy metals and other toxic chemicals, such as cadmium and mercury, solvents and pesticides, enter our wastewater treatment plants every day. Many of these substances come from industries and business that dispose of chemicals in their wastewater as part of their regulated industrial processes. They also come from people who use and improperly dispose of hazardous household items such as cleaning products, paints and pesticides. One potential source of lead and copper in wastewater comes from corroding pipes in existing building plumbing systems. Some toxins in wastewater begin as air pollutants that have fallen to the ground and are carried by rain water to our plants and waterways. Wastewater treatment plants cannot destroy all of these substances so they remain in small amounts (still below standards set by the State and federal governments) in the treated wastewater discharged to local waterways.

DEP tests the treated wastewater effluent released from all 14 treatment plants daily for conventional pollutants, and annually for over 130 “priority pollutants” that the United States Environmental Protection Agency (EPA) lists as the worst pollutants to ensure that federal and State standards are met. These include metals and organic chemicals. DEP runs programs aimed at reducing some key sources of toxic substances.