City expanding food-waste program
New York City will expand a pilot program this fall that takes uneaten food from the waste stream and converts it into pipeline-quality natural gas.
If successful, the Department of Environmental Protection hopes the progam will provide valuable information to the renewable energy industry while also leading to a significant reduction in the city's carbon output.
Converting the waste will reduce truck traffic, landfill pollution and reliance on traditional fossil fuels for energy, city officials said.
"We're looking at avoiding approximately 90,000 metric tons of carbon dioxide which is equivalent to 19,000 vehicles being taken off the road," said Anthony Fiore, director of the D.E.P.'s Office of Energy.
The city launched the pilot program last summer, processing between 1.5 tons and 2 tons of organic food waste a day. The material is separated from the regular trash by Waste Management, the private waste disposal firm, and carted to the Newtown Creek Wastewater Treatment Plant in Greenpoint, where it is added to nearly 3,000 tons of domestic sludge the facility processes every day.
Under the expanded program, Newtown Creek will begin processing 50 tons of food waste a day. National Grid will develop a mechanism to convert the resulting methane into pipeline-quality gas which can be sent back out to consumers.
Newtown Creek could pass as an alien landing pad, with 80-foot high, stainless steel "digester" eggs filled with sludge that, like giant stomachs, pulls as much energy from the waste as it can.
Fiore said adding food waste to the mix significantly boosts the energy capacity of the sludge.
"It has a much higher energy content," he said. "In the sludge, much of the energy has been taken out by us."
Newtown Creek uses 40 percent of the gas it creates to help fuel its own facility. The remaining 60 percent gets burned off or "flared." The next phase of the program will aim to put much of that gas to use.
"Our partnership with D.E.P. on the Newtown Creek Renewable Gas Project, a first-of-its kind project to demonstrate that renewable gas is a viable and economic option, is an exciting clean energy initiative to achieve this vision," said Ken Daly, president of National Grid New York.
Fiore said that under the expanded program, the city hopes to eventually process 250 tons of food waste a day. The plant could ultimately process up to 500 tons or 15 percent of the city's residential organic waste, he said.
The city Department of Sanitation department has been trying to keep as much food waste out of landfills as possible so it can be used for renewable energy and composting.
Those efforts include Local Law 146, adopted in 2013, which requires large food retailers, including chain restaurants, supermarkets and large-scale caterers, to separate food waste from the rest of the daily trash. That waste is carted away by commercial haulers.
The sanitation department has also launched voluntary programs with residential neighborhoods and schools to get people to separate food scraps from the rest of the trash. Last week, Mayor Bill de Blasio's daughter, Chiara, filmed a promotional video urging people to use brown bins offered by the sanitation department to separate organics from other trash and recyclables.
Aside from the environmental benefits the city hopes to achieve from expanding the pilot program, Fiore said he is hoping to make a contribution to the body of knowledge surrounding biogas.
"We're going to partner with academic institutions," Fiore said, adding that most studies on biogas conversion "have really focused only on biogas production ... very few studies have looked at side effects."
Fiore said the city will be examining digester chemistry, or compounds that are most effective in breaking down the food. D.E.P. will also examine the sludge that is produced, how it is de-watered, and what can be done with the final waste product, referred to in the waste management business as "cake."
"It's really cutting-edge knowledge that will be available for the industry," he said. "We will be making all this data publicly available."
While the program follows on initiatives started under former mayor Michael Bloomberg, the de Blasio administration is hoping to make it a significant part of their sustainability agenda.
"In addition to reducing waste sent to landfill, this program reduces greenhouse gas emissions and increases the in-city capacity for renewable energy—a key goal of our sustainability plans as we work to mitigate our contributions to climate change," said de Blasio spokeswoman Amy Spitalnick.
CORRECTION: This story initially stated the Newtown facility processes 3 million tons of sludge per day. The correct figure is 3,000 tons.