New York City’s 14 Wastewater Treatment Plants together treat 1.3 billion gallons of wastewater daily. Each person can help our wastewater treatment system run better by conserving water, disposing of garbage and household chemicals properly and being concerned about water quality in the New York City’s waterways. To learn more about how you can help protect our sewer system and local waterways, visit Safe Disposal of Harmful Products. To learn more about the types of sewer systems that serve New York City, visit Sewer System.
Wastewater Treatment Plants
The amazing treatment system that cleans our wastewater consists of: over 6,000 miles of sewer pipes; 135,000 sewer catch basins; over 495 permitted outfalls for the discharge of Combined Sewer Overflows; 95 wastewater pumping stations that transport it to 14 wastewater treatment plants located throughout the 5 boroughs.
Wastewater Treatment Process
When you take a shower or brush your teeth, do you ever wonder where where the used water (we call it “wastewater”) goes? Each day, we treat 1.3 billion gallons of wastewater at New York City’s 14 wastewater treatment plants.
Sludge is the solid byproduct of wastewater treatment. Once further processed, its use is regulated by both the federal and state governments. New York City’s sludge is digested, which is a form of processing that microbiologically transforms material and creates “biogas,” a type of renewable energy. Learn more about Resource Recovery.
After digestion, the leftover solids are then dewatered. Dewatering is a process where the solid components of sludge are separated from the liquid components mechanically (we use centrifuges). Not all of the city’s 14 wastewater treatment plants have onsite dewatering facilities. Those facilities without dewatering capabilities transport their solids through force mains or marine vessels to in-city treatment plants that have onsite dewatering capabilities. After dewatering, the leftover solid product of the processed sludge is generally referred to as “biosolids.” The city’s biosolids are managed by outside contractors who take it to landfills for disposal or further process it to recover its value as a nutrient-rich soil amendment.
As part of the mayor’s plan for OneNYC, we have a goal of zero-landfilling of biosolids by 2030. This means we will develop a program to reuse all biosolids beneficially. Some of the further processing technologies that can be used to qualify biosolids for reuse include composting, drying, and gasification or pyrolysis. New York City produces about 1,400 tons/day of biosolids or about 60 truckloads! Such a large quantity spread out over our 6 dewatering facilities means that our beneficial use program will need to be diverse and include multiple types of further treatment.
To learn more about biosolids, we recommend visiting:
Significant Non-Compliance List
DEP is required to publish a list of establishments in New York City that were in significant non-compliance with pretreatment standards and other wastewater requirements.