New York City wants to attract companies to build more digester eggs, like these at Newtown Creek – to turn its food waste into natural gas. [Image Credit: Nick Stockton]
Jimmy Pynn has his audience in the palm of his hand. For the past hour he’s led them, oohing and ahhing, through a modern industrial marvel. Now they surround him, on a glassed-in platform 14 floors up, face-to-face with the New York City skyline.“If Donald Trump knew what the view of Manhattan looked like from over here, there’d be condos here in Greenpoint,” he says. “But he don’t, so we got a waste water treatment plant!”
Pynn is the director of the Newtown Creek Wastewater Treatment Plant, near the border of Brooklyn and Queens. It’s possible that there were more “eww’s” than “ooh’s” on the tour (Pynn was tangibly excited to show off the “’hair traps”’), but there was also a fair amount of awe. For example, the crowd got its skyline view from atop a 145-foot tall stainless-steel egg – one of eight – that has 3 million gallons of stewing sewage being consumed by trillions of methane-burping bacteria.
The eggs are the plant’s pride and joy, and the climax of Pynn’s tour. Not only do the bacteria inside purify the contaminants in treating the sewage they eat, the plant also uses the methane they burp up to offset its massive energy appetite. And when the bacteria are done, the leftover slurry makes great fertilizer. It’s natural, efficient and a relatively cheap way to treat New York’s millions of daily flushings.
But the bacteria aren’t picky, they can also dine on food waste. On Thursday, city and private industry leaders announced that the digesters will soon eat up to 500 tons of New Yorkers’ scraps a day, and burp up enough gas to heat up to 5,200 homes. The announcement comes after the city council recently extended a pilot food waste collection program.
Recycling those scraps would get the city closer to outgoing Mayor Michael Bloomberg’s green goals, and would also take a big bite out of the city’s landfill costs. But this ambitious plan – which includes partnerships from National Grid (the city’s largest natural gas supplier) and Waste Management (one of its largest trash collectors) – could eventually outgrow Newtown Creek. Any new digesters – which the city officials hope will be privately built and operated. Before businesses can build, though, the city needs to convince them it can supply the food waste, which means it has to convince New Yorkers to separate their food waste.
Ron Gonen has his work cut out for him. Last April, the city’s newly hired Deputy Commissioner of Recycling and Sustainability launched the food collection pilot program, starting with 2,000 Staten Island homes and 90 Brooklyn public schools. The feedback was better than expected, so in June the City Council voted to continue and expand the program. Under the renewed mandate, Gonen rebooted in September with nearly 30,000 homes in Staten Island, Brooklyn and the Bronx, and an additional 102 Brooklyn public schools. He expects the program will triple in size within a year. Currently, most of the food is composted. But, a small portion – about 10 tons – is ground up by Waste Mangement – a private waste collection company – and added to Newtown Creek’s gleaming steel eggs. “The city had tremendous opportunity to take what they were putting into landfills and find a renewable use,” says Gonen. “One of the great ways to process organics is to convert it into methane gas.”
Anaerobic digestion – bacterial decomposition in the absence of oxygen – is not new. In 1883, a Frenchman named John Mouras was awarded the patent for a technology he called the “automatic scavenger.” Other Industrial Age innovators improved its design and optimized it for treating sewage. In 1897, the English port of Exeter was the first to use these “septic tanks” city-wide. It wasn’t long before they realized the methane gas was flammable, and soon they were burning it to provide heat and light the gas lamps at the treatment plant.
Treating sewage waste alone, Newtown Creek produces about 3 million cubic feet of gas a day. Pynn uses about 40 percent of that to maintain the temperature in the eggs. The rest is cleanly flared off into the atmosphere. The raw gas is too wet and rich with carbon dioxide for residential use.
This will soon change. As per Thursday’s announcement, National Grid hopes to begin building construction next summer and complete the project by mid-2015. According to DEC press official Ted Timbers, the project won’t have any direct cost to taxpayers, either. “National Grid will finance design, construction, operation and maintenance,” he says. “Once the costs have been recouped, the profits will be split between National Grid and the DEP’s customers.” Profits, of course, would come in the form of lower gas bills, not mailed rebates.
This deal will be even more important once Mayor-Elect Bill de Blasio goes full bore with the food collection program, as expected. With a fresher diet, the digesters would pump out higher grade fertilizer and also more methane, which can be converted to electricity or just burned as gas. Of course, the city’s end game isn’t just to send food waste to Newtown Creek; after all, the city creates over 4,000 tons a day. The waste facility is only a testing ground. Ideally, the city would like to scale the program up and lure private companies to build additional digesters in and around the city.
Anaerobic digesters are basically large, bottled versions of the bacterial cultures that animals use to turn food into usable energy. Like the bacteria in the gut, they are most productive when their environment is a slimy, 98.6 degrees Fahrenheit. The digester eggs are much more efficient than our guts, though. From one end to another, a meal travels through a healthy human in little more than a day. But mammals’ systems are inefficient, and scuttle a lot of energy. Anaerobic digesters are much more thorough, so the food typically spends a month being munched on by bacteria.
Making gas might be sexy (well, sexy in the waste management world), but digestion’s real value comes from keeping waste out of landfills. Since it closed the FreshKills landfill on Staten Island in 2011, the city has been exporting all its waste. At roughly $125 a ton (more than any other city in the country pays), this adds up to about $310 million a year for residential waste alone. About a third of that waste is food scraps. Though it’s too early to calculate the potential savings, a City Council aide working on this project believes that sending a ton of food to a digester will cost half what it would take to ship a ton of food to a landfill. Food waste left to rot also has an environmental cost, and the natural gas purification system will keep about 90,000 tons of methane and carbon dioxide out of the atmosphere every year.
But, Newtown Creek can only handly 500 tons of waste a day – New Yorkers throw away close to 4,000 tons a day. If the plan keeps ramping up, the city will look for outside businesses to build and operate new digesters. In March 2012, as part of Bloomberg’s plan to make the city a paragon of eco-friendliness, the city put out a press release inviting businesses to pitch ways to convert waste into energy. There’s been significant interest, but the city still needs to prove to these businesses that the Sanitation Department can supply them a steady stream of wasted food.
This is a classic chicken-and-egg problem, explains Paul Sellew, chief executive of Harvest Power, an anaerobic digestion company. He sees New York as a big opportunity, and is eager for the program to succeed. But, he says Gonen is right to take a slow, steady approach. “We’re not used to looking at things in 20-year windows,” he says. Digesters need a steady supply of feedstock, or else they starve and the operators lose money. “Look, this is not a ‘snap-your-fingers, let’s go’ kind of thing: It’s the beginning of a 20-year infrastructure build-out,” he says.
New York’s digester would be an order of magnitude larger than the largest commercial digester in North America, which Harvest Power built recently for a suburb of Vancouver, B.C. That project serves 200,000 people, and Sellew said he overcame many challenges – siting, permits, regulations – to get it done. Of all the challenges, he says nothing compares with convincing people to store rotting food in their homes.
Adam Danforth is a butcher living in Greenwood Heights, one of the Brooklyn neighborhoods included in the compost program’s pilot stage. After delivering an explanatory flier, the city supplied him with several small counter-top bins, three months of biodegradable plastic bags and a larger, outdoor container. After his first week, which started in late September, he said he got used to putting his food scraps into the bin. He supports the program, but believes it won’t be for everyone. “My neighbors – they’re in their mid-50s – they say, ‘No way I’m going to have that bin on my counter,” he says. “There’s that attitude that it’s not an attractive thing.” Danforth admits there is an ick-factor. “They give you these liners that puncture pretty easily, and then you have this ooze that comes out. After one week, our bin definitely smells terrible.” Despite this, Danforth thinks it’s just a matter of time before the bin will become a seamless part of his kitchen routine.
Other cities are watching how New York ramps up its participation. Madison, Wis. is starting its own food collection program soon. George Dreckman, the city’s recycling coordinator, says they are probably going to invest directly into anaerobic digestion. “It seems to me that it’s the 21st century infrastructure solution for capturing the full value of the product,” Dreckman says. Besides, he adds, Wisconsin is too cold for too many months for food to break down efficiently via traditional composting. Every food collection program is different, he says, but New York’s scale is giving cities like his a sense of which types of obstacles are surmountable.
So far, Gonen’s pace and plan has a lot of support. Recently the City Council voted to fund the collection program for another two years, and City Council insiders expect that mayor-elect de Blasio will continue it afterward. For the 2014 fiscal year, ending next October, the city estimates the program will cost around $10.6 million. City officials are hesitant to label the food-to-energy plan as anything more than a pilot. However, these recent stirrings in the brown energy movement seem like a subtle guarantee that food will keep filling the empty space Jimmy Pynn’s shiny eggs.