Green solutions for New York City's overflowing sewers

In late July, Harlem residents held their noses as millions of gallons of untreated sewage water flowed straight into the Harlem and Hudson Rivers because of a sewage plant fire. On the hottest day of the year, precious beaches and water areas were off limits, too toxic to swim in, as a repair team took shifts working in the heat to fix the plant.

But the crisis was more than just an isolated incident; it was symptomatic of a larger, structural problem in the way New York City – home to 8.5 million people – deals with its residents’ liquid waste.

Each year, 27 billion gallons of raw sewage are dumped into the New York City harbor, making sewage, or more specifically, the city's inability to process waste water, the largest source of water pollution in the city. This dumping is caused by combined sewer overflows that occur when the sewer system becomes overloaded by heavy rain on top of normal sewage flows. Overburdened city infrastructure is simply not capable of handing so much water.

The solution to this problem may lie in what is known as “green infrastructure.” Green infrastructure, according to the Department of Environmental Protection and PlaNYC, the city’s sustainability initiative, includes “advanced tree pits, porous pavements and streets, green and blue roofs.” It is essentially anything that is built in to the city’s currently existing infrastructure that makes systems, like sewage collection and treatment, run more smoothly.

Large-scale, industrial solutions, such as 50-million underground sewage storage tanks, are simply not affordable given New York City’s budget constraints. And the return on investment for these tanks is diminishing rather than growing according to PlaNYC. Therefore, other solutions must be taken seriously.

With green infrastructure, the city aims to reduce combined sewageo utflows by “manag[ing] runoff from 10 percent of the impervious surfaces in combined sewer watersheds through detention and infiltration source controls.” One tangible way to do this: the MillionTreesNYC campaign, which is planting trees throughout the city not only to provide shade, but also to create more treebeds that absorb rainwater.

But to many sustainability activists, the city’s green infrastructure plan is just a stop-gap measure, well-intentioned but too centralized and bureaucratic.

The approach of the Stormwater Infrastructure Matters (S.W.I.M.) coalition differs. The coalition views stormwater as a resource, rather than a waste. It wants to improve water quality through “natural, sustainable stormwater management practices in our neighborhoods,” according to its website. It has more than 70 member organizations working on infrastructural water issues in New York City.

After the recent North River sewage plant crisis, S.W.I.M. released news that the level of pollution in the Hudson River was much higher than the Department of Environmental Protection (DEP) had announced.

“Riverkeeper is one of our member organizations,” explained Kate Zidar, the coordinator of S.W.I.M. “They sampled in the middle of the river and near the shoreline; they did a comparative grid. It’s not totally clear to me how DEP tests; typically they test midstream. Riverkeeper found the pollution because they looked for it.”

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