A nitrogen-reducing wetland has replaced decades-old cesspools at the office and residential complex at The Nature Conservancy’s Uplands Farm Sanctuary in Cold Spring Harbor, Long Island. The plant-based wastewater treatment system will convert harmful nitrogen in raw wastewater into a harmless gas. Nitrogen pollution is to blame for numerous water quality issues on Long Island including harmful algal blooms that kill fish and make it unsafe to use affected ponds and lakes for recreation and shellfishing. Watch the video to see how it was done. To learn more, read a description of the project from TNC’s Long Island Sound Futures Fund award or read a fact sheet.
Grantee: The Nature Conservancy, Long Island The Nature Conservancy, Long Island will construct and publicize the results of the first nitrogen-reducing vegetated wastewater treatment system in Cold Spring Harbor, Suffolk County, New York. The project demonstrates a system that treats wastewater in a natural manner, reduces nitrogen discharges, and safely removes pathogens providing an alternative to traditional waste treatment in cesspools which contributes nitrogen and other pollutants into Long Island Sound. The project will install a vegetated wastewater treatment system at an office and residential complex in Cold Spring Harbor, and publicize this attractive, plant-based treatment method in Suffolk County, New York. Excess nitrogen is a threat to the health of Long Island Sound. A Nitrogen Loading Model assessment found that nitrogen from septic systems/cesspools is the major land-based source of nitrogen in 12 of 13 Sound watersheds from Little Neck Bay to Northport Bay, including the Cold Spring Harbor watershed where Uplands Farm is located. The project will: 1) sample soil and groundwater pre-construction to assess the quantity of nitrogen leaving the current cesspools and determine baseline levels in the area where the new system will be located; 2) Sample post-construction to determine nitrogen reduction; and 3) install a hybrid moving bed bio-reactor and a constructed wetland using native plants to handle follows of 1,000 gallons per day. The system size can be adjusted to adapt to larger-flow homes, clusters of homes, or offices. The plantings provide botanical for nitrification, which will be followed by de-nitrification. A drain field for effluent will further absorb nitrogen; and 4) publicize through site visits, signage, short videos, social and traditional media, and conference presentations. The project will reduce nitrogen in the effluent to nearly zero, and by at least 90 percent resulting in a reduction of at least 150 pounds of nitrogen annually.