Every year around 20 billion gallons of untreated sewage streams into the waterways of New York City during overwhelming rainfalls. Attempting to stave off health risks, the city has a plan: pour chlorine into sewer pipes. But environmental advocates say the technique is shortsighted and worrisome.
The city has attempted a few fixes to the issue, such as new retention tanks and greenery planted to reduce runoff. Now they want to disinfect wastewater inside pipes with chlorine; those pipes lead to three bodies of water in the Bronx and Queens. Riverkeeper staff lawyer Sean Dixon told The New York Times, “They’re using the most worrisome and unproven technique that we have in our toolbox. It’s like they’re grabbing the last straw and using the cheapest and least effective method.”
Dixon said chlorine sometimes doesn’t even disinfect sewage completely, and doesn’t treat certain toxins. Further, residual chlorine can harm marine life. Chlorination is commonly utilized in wastewater treatment plans, not pipes that run into waterways.
New York City Department of Environmental Protection spokesperson Ted Timbers said chlorine is “the most widely used disinfectant for water and wastewater treatment in the U.S.” He said the plan had been talked about in meetings with the public, and that chlorination would occur from May to October.
Queens College hydrologist Timothy Eaton said chlorine can be effective in controlled settings, but with unpredictable changes in sewage flow, residual chlorine could be left behind and the exact dosage would be tricky to get right. He told The New York Times, “It’s very difficult to predict the amount of water you’re going to get at any period of time. If you overdose it, you’re basically treating Flushing Creek and Flushing Bay like swimming pools.”