Recycling Newtown Creek will convert food scraps to biogas

Published on December 28th, 2013 | by Tina Casey


Giant Gleaming Eggs Will Help Solve Urban Water, Energy And Waste Problems

December 28th, 2013 by  

Not too long ago, cities could be labeled strictly as takers: taking in food, water, energy and other resources, while dumping out mountains of garbage and oceans of polluted wastewater. But take a look at the gigantic egg-shaped structures that dominate New York City’s Newtown Creek wastewater treatment plant, and you’re looking at the key to a sustainable future.

The distinctive landmarks are digesters that convert municipal wastewater into biogas, and New York has just announced a new food waste recycling/wastewater project that will enable the digesters to accept food scraps from households, schools, and other institutions.

Newtown Creek will convert food scraps to biogas

Newtown Creek wastewater treatment plant (cropped) by Victoria Belanger.

Food Waste Recycling And Biogas

The new project is a giant step forward for New York, because it will enable the city to sell biogas from the digesters into the commercial natural gas market.

Although the city has long reclaimed some of the biogas to help power operations at Newtown Creek, the raw gas is unsuitable for domestic purposes because it is too “wet” and rich in carbon dioxide.

San Antonio, Texas actually lays claim to the first commercial wastewater biogas hookup in the US,  but if the Newtown Creek project is adopted at the city’s 13 other treatment plants, the New York project will be by far the largest.

In partnership with the company Waste Management and utility National Grid, the Newtown Creek project will convert food waste/wastewater biogas to a commercial-grade product that can be sold off site, with the goal of reclaiming 100 percent of biogas generated by the digesters.

The implications for sustainable urban development are enormous. One critical obstacle that cities face is the skyrocketing cost of wastewater treatment, so the prospect of offsetting costs by generating and reclaiming energy would enable more wastewater treatment projects to get off the ground more quickly.

It’s worth noting here that digesters house a process that is, literally, natural digestion. Digesters create an optimal environment for microbes to feed on the organic materials in wastewater. Along with generating gas, the microbial process provides an additional level of wastewater treatment without added chemicals and with a minimal use of energy.

The digestion process also yields an organic soil-like material that can be reclaimed as compost. In short, digesters provides a sustainability three-for-one: cleaner effluent, a soil enhancer to grow more biomass, and reusable biogas.

The reclamation of biogas from human waste also offers an intriguing window into next-generation urban sustainability, by harnessing the energy generated by huge numbers of people as they move through the processes of daily life.

Another good example of urban energy harvesting from “people power” is piezoelectricity, in which certain materials generate electricity when exposed to stress. This effect is being explored as a means of generating energy from crowded urban facilities such as train station platforms and even dance floors.

Devices that harvest kinetic energy from the simple act of walking are also in development, and the principle of kinetic energy can also be applied to people-powered devices common in the urban environment such as turnstiles and revolving doors.

By extending the people power principle to the mechanics of urban life, you get energy harvesting opportunities from roadways as well elevators, commuter trains, and stop-and-go traffic in the form of regenerative braking.

Put it all together and you have the city of the future as a gigantic energy generating and resource reclamation dynamo.

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[This article has been submitted to Masdar Engage. You can find it here.]

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About the Author

specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. Views expressed are her own. Follow her on Twitter @TinaMCasey and Google+.

  • Pat

    This is again overly complex for small towns and cities that have limited budgets. First we need to use urine separators that will keep the least biological hazard portion out of our potable water supply and move it to where it can be applied to crops with little or no extra treatment. Next we need to compost the feces then when they are biologically safe till them into the soil. All this could take relatively little energy and save intensely processed potable water for the most valuable uses rather than as a transportation method.

    • Bob_Wallace

      Farms are installing biodigesters to deal with feedlot and dairy barn wastes.

      People in India make biodigesters out of mud in order to turn cow poop into cooking gas.

      Small towns can do the same.

      This is a scalable technology.

      • Matt

        Yes the general approach is scalable, Mother Earth News gave plans for a DYI version you could build on your homestead back in the 70’s. My guess is the above is a updated version, but the same idea. Hopefully it is a improvement on the idea.

        • Bob_Wallace

          Here’s a couple household sized units…

          • Matt

            You can see lot of medium sized ones on farms in the US. When you have lot of cows/pigs/chickens they make a lot of waste. On the order of a small town.

  • heinbloed

    A sewage treatment plant……

    what is new about this concept?

    It is used in Europe since about 60 years, state of the art.

    The sewage treatment plants are still faced with the problem where to put the hazardous waste they create.

    None of the gas will reach the grid since CHP generators being fed with methane are producing just enough thermal and electrical energy to suport the plant. Digesters need warmth, pumps need electricity.

    And there is no perpetuum mobile.

    • RobS

      This is not in any way a perpetual motion machine because it has an ongoing input of energy into the system in the form of new organic waste. Suggesting biodigesters use as much energy as they produce and therefore are not net energy producers is just plain wrong.

    • 2pad

      Hazardous waste? I build these for a living… “The Two-Phase Anaerobic Digestion System separates the acid- and
      methane-forming stages of sludge digestion. Because pathogens are
      destroyed below detectable limits, the resulting biosolids are rated
      Class A and can be land-applied without restrictions in accordance with
      EPA regulations”

  • JMin2020

    Thanks for the post Tina. It is good to see NYC making sensible use of a lot of waste.

  • Corbin Holland

    I love reading about new ways engineering is providing us with economical ways to go sustainable!

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