So far, nothing from the city’s curbside composting program has been composted. But gas produced by the scraps is now consistently flowing into pipelines to serve homes.
For 20 years, New York City officials have discussed developing a compost program, and for a decade they have experimented with small-scale versions.
Finally, last month, Mayor Eric Adams launched a citywide initiative to collect food scraps curbside, starting in Queens. Now, with the program scheduled to expand to the five boroughs by the end of next year, city officials will need to figure out what to do with it all.
Officials hope to transform a problem into an asset, creating useful products like fertilizer and energy. The goal is to keep the city’s roughly eight million pounds of daily residential food waste from rotting in landfills, which produces harmful greenhouse gases, and to save costs on hauling food garbage.The plan’s success depends on developing local processing capacity not yet in place. And as officials ramp up the logistically complex program, they are working to reuse all the products they derive from the food, instead of sending a small portion to landfill.
The program is called “curbside composting” — but so far, nothing is being composted. The food scraps collected in Queens go to two sites to be “digested” — microorganisms break down most of the material in tanks, creating biogas and a reduced mass of solid, nutrient-rich concentrate that can be used as a fertilizer or soil replacement.
At one of the two sites, the Newtown Creek Wastewater Treatment Plant, food scraps collected from western Queens are mixed with sewage. Once processed, they produce more gas than is needed to heat the plant. A decade ago, officials planned to inject that excess gas into the pipelines of National Grid, but there were years of delays.
On March 31, for the first time, the plant began consistently injecting cleaned and refined gas into the pipelines of National Grid to serve about 2,500 homes.
As the plant processes more food, it could eventually provide enough gas for heat, hot water and stoves in 5,200 homes. This would reduce annual carbon dioxide emissions from burning fossil fuels by more than 90,000 metric tons, the equivalent of removing nearly 19,000 cars from the road, officials said.
“This is an important step,” said Rohit T. Aggarwala, the commissioner of the city’s Department of Environmental Protection, which operates the Newtown Creek facility. “We really need ultimately to have a true circular economy for organics in New York City,” he said.
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But not all the products of the digestion process at Newtown Creek are being reused.
Imagine a rotting onion that has been minced and liquefied for processing. Roughly 75 percent of that onion will be transformed into biogas — all used to heat the plant and nearby homes. Some 25 percent of it will break down into a cakey nutrient-rich material — most used productively to replenish soil at agricultural and mining sites. But officials are currently sending about 5 percent of that onion to landfill, potentially as far away as Ohio.
“We can do better,” said Shahana Hanif, a member of the City Council who sponsored a bill that would require separating food scraps, just as New Yorkers must recycle glass, paper, plastic and metal and now also yard waste — though she called reusing 95 percent of food collected “an achievement.”
