Wastewater Treatment

New York County Plan Eliminates Cesspools & Septic Tanks

Dividing county into 190 watersheds aims to reduce nitrogen pollution

Aug. 15, 2019
2 min read

In Suffolk County, N.Y., a $4 billion plan will transition the county away from cesspools and septic systems so as to reduce nitrogen pollution in groundwater and surface water, according to the Riverhead News-Review

“This plan represents the first meaningful strategy to address legacy septic nitrogen pollution since countywide sewering objectives were abandoned some four decades ago,” said Walter Dawydiak, director of environmental quality for Suffolk County, according to the Riverhead News-Review.

The Subwatersheds Wastewater Plan will eliminate more than 253,000 cesspools countywide. According to the Riverhead News-Review, the county will replace them with wastewater systems or connect properties to existing sewer districts. The first step of the plan divides the county into 190 watershed areas and sets goals to reduce nitrogen pollution, according to the New York League of Conservation Voters.

74% of county residents rely on on-site wastewater disposal systems, such as cesspools or septic tanks. According to officials, if the plan is implemented, poor water quality could reverse in the next decade.

Nitrogen concentrations have increased on Long Island surface waters since the 1980s, according to the NYLCV. Nitrogen levels rose 200% between 1987 and 2005 in the Long Island aquifer and are expected to rise more, according to a Long Island Commission for Aquifer Protection study. This contamination contributed to the decline of the shellfish industry, and the nitrogen also contributed to the growth of harmful algae blooms (HABs), according to NYLCV. HABs produce toxins detrimental to the water and organisms. 

HABs in Suffolk County largely are due to the outdated sewage system that the county uses, according to NYLCV. 74% of the county is not connected to the public sewer system and 70% of nitrogen in local bays comes from more than 360,000 cesspools and septic systems.

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