Capturing Energy Riches from Our Waste Stream

February 15, 2011

Park Spark Project provides anaerobic digester, where dog waste is converted methane, a burnable fuel for this gas light. Photo: Park Spark Project

Times change, thankfully. Instead of thinking first about how to get rid of waste, more people are now asking how they might put parts of the waste stream to use.

Some landfills now capture methane to power massive generators that feed electricity to the grid; a California company makes biodegradable plastic from organic waste without using petroleum. The list of companies and people involved in promising and innovative work continues to grow.

Dog poop is now on the list of viable new materials from that can be harvested and used from the waste stream. Last year in Cambridge, MA, conceptual artist Matthew Mazzotta launched the Park Spark Project, using dog feces to power lampposts in a park.

Mazzotta’s Park Spark Project was funded through MIT and created in partnership with the City of Cambridge. Methane, a common greenhouse gas, is created in a methane digester that converts freshly scooped poop into burnable fuel.

Dog owners collect dog droppings in biodegradable bags, then toss the mess into the digester –- a closed cylindrical container, where the dog feces are broken down by anaerobic bacteria. This process creates methane that is then released through a valve and burned to power an old-fashioned gas-burning lamppost in a park.

Mazzotta has said he hopes to install permanent underground digesters in parks, not only in Cambridge, but also throughout the country.

Mini bio-gas digester from E2Conserve sells for $420 Photo: E2Conserve

Plenty of other organic materials can be fed to this type of digester, including other animal waste, plus food and plant matter. The digester’s products include fertilizer – as any good gardener should know – and methane – a standard greenhouse gas that can be tamed when it is burned as a fuel.

Companies like E2Conserve now manufacture and sell small digesters at affordable prices, opening the doors for experimentation and community involvement similar to the Park Spark Project. Access to biotech tools like this is positive news for schools, garden clubs and small farms – even neighborhoods wishing to participate in problem-solving projects.

E2Conserve manufactures small scale biogas digesters priced at $420. According to the company, its 35 cubic-foot methane digester can handle farm waste from poultry, cattle, pigs, horses, up to 66 pounds a day. It also handles food waste, leaves, twigs and shredded waste.

The company lists these benefits:

  1. For farm and plant wastes up to 66 lb/day and kitchen wastes up to 17 lb/day
  2. Methane/biogas (can be used for cooking/heating) – 35ft3 (1 m3)
  3. Electricity – up to 5 Kwh equivalent/day (requires additional generator)
  4. Organic fertilizer/manure – up to 6.61 lb/day
  5. A very neat and cheap way to solve your waste management problem
  6. Free methane gas for cooking and heating
  7. The digested slurry from the Mini Biogas digester is an excellent organic fertilizer and soil conditioner
  8. An activity to reduce greenhouse gas generation.

With the world economy still reeling from an abundance of gloomy economic news, the digester business could be a very sweet place to be working, for many good reasons.



Glenn Meyers

Writer, documentary producer, and director. Meyers is a contributor to CleanTechnica, and founder of Green Streets MediaTrain, a communications connection and eLearning hub. As an independent producer, he's been involved in the development, production and distribution of television and distance learning programs for both the education industry and corporate sector. He also is an avid gardener and loves sustainable innovation.