The Making of “Black Gold”

Since the massive Stuyvesant Town and Peter Cooper Village apartment complexes signed on with the city’s curbside collection of organic waste last December, 15 percent of the 27,000 residents have signed up. As a result, according to Rei Moya, the director of environmental services at the East Side complexes, more than 10,000 pounds or organic waste – chicken bones, egg shells, tree branches and such – has been diverted from landfills. The city has moved a step closer to its goal of ending all shipments to landfills by the year 2030. 

So where do all those tons of organic waste go? And what becomes of them? 

There are now only two sites in the five boroughs that can process organic waste – one on Rikers Island, the other at Fresh Kills on Staten Island – so the city has contracted with six out-of-town companies. City trucks deliver the organic matter to these contractors, who proceed to turn it into compost or usable biogas.

Composting, or controlled decomposition, uses billions of microorganisms to break down organic waste. The process requires a proper mixing of “green” organic materials (nitrogen-rich grass clippings, coffee grounds, and food scraps) and “brown” organic materials (carbon-rich dry leaves, wood chips, and branches). The mixture is churned by hand or machine to promote decay. It takes six to nine months for matter to decompose completely and arrive at the state farmers refer to as “black gold” – nutrient-rich fertilizer that prevents soil erosion and helps plants take root. 

And then there is anaerobic digestion, which has been called “the next revolution in recycling.” These facilities use microbes to break down organics into biogas, primarily methane and carbon dioxide. Machines grind organics into a slurry, which is fed into a large airtight tank called a digester, where it is heated to about 100 degrees. This produces biogas, mixed with water and solids. After refining, the biogas can be fed into a natural-gas pipeline or used as fuel for trucks and buses. It can also be converted to electricity and heat. Only a small portion of the city’s food waste is currently converted into biogas, but as the collection program expands, that is sure to change. 

One beneficiary of the city’s composted organic waste is the 5,000-square-foot community garden, La Casita Verde, in South Williamsburg, Brooklyn. The garden, which was founded on a neglected lot in 2013, now produces its own compost and receives a dump-truck’s worth of free compost from the city each growing season. The garden yields a yearly crop of eggplants, tomatoes, watermelons, squash, herbs, and medicinal plants. When the Department of Sanitation announced the expansion of its organics recycling pickups this spring, it staged the announcement at La Casita Verde. 

“The point of composting is that it’s the right thing to do, and it’s magic,” says Brooke Singer, a professor at SUNY Purchase who helped establish La Casita Verde. “You bring in waste and see what a fabulous resource it is. Compost is so much richer than regular soil, and people who do composting say they can’t believe how much less garbage they send out to the curb. About half of our garbage is organic matter.”

Singer, who began composting long before she helped establish the community garden, believes New Yorkers are finally overcoming resistance to the notions of recycling organic matter and returning its byproducts to the city’s soil. “There are a lot of barriers to acceptance,” she says, “but DSNY is making it happen – not only physically, but through PR and education and outreach to get people on board. I have no doubt they’ll succeed.”