Environment: Making it better wherever you are
What To Do About All This Poo?
It’s happened to all of us. You’re out for a walk in the park and squish - you’ve stepped in dog poop. If only we could train our dogs to line up to use a public restroom, flush, and wash paws before they leave. Until dogs have mastered the fine art of toilet etiquette, it’s us humans who have to clean up after them.
Cities around the world have passed laws based on health ordinances that require people to pick up their dog’s poop and deposit it in a waste receptacle. However, what about all those plastic bags of doggy doo? What happens at the landfill where they accumulate? How many millions of doo doo bags wind up at the dump? Who knows, but what happens at the dump doesn’t stay at the dump. Methane gas emits from these little bags of waste and that’s where the problem becomes atmospheric. Couldn’t we try to harness all this free energy floating skyward? Methane gas from global animal waste is contributing to global warming at a rate higher than carbon emissions. What to do about all this poo?
Thankfully, there’s Streetkleen, a company in the UK that has developed a bio digester system that is converting dog waste into energy instead of having it languish in landfills.
The London Daily Mail has an article about the entrepreneur, Gary Downie, and why he became involved in such a messy business. Mr. Downie, a father of two small children, became fed up with having to wash the dog poop off his daughter’s stroller wheels. So he set about to do something productive to solve the problem.
As an introduction, there’s an interesting video on the Streetkleen website homepage which takes you on a field trip to an animal waste processing plant. They’re producing enough biogas at this factory to power 160 houses. That’s a village!
For those who want to learn more about the science of the process, there’s an extensive amount of knowledge on Streetkleen’s website. Here’s an excerpt on the benefits of the program:
Dr John Walsh, Streetkleen Bio Ltd - Director of Economic and Environmental Management
Benefits of Anaerobic Digestion:
Dr Walsh undertook a 3 year PhD study at Bangor University to recognise and quantify the economic and environmental benefits of anaerobic digestion and the residual bio fertilizer (digestate).
• Methane - released to the atmosphere during normal storage and utilisation of organic waste. Methane is 23 times more potent as a greenhouse gas than carbon dioxide (CO2). Anaerobic digestion (AD) collects methane and provides a source of renewable energy that is carbon neutral i.e. provides energy with no net increase in atmospheric CO2.
• Fertiliser - compared to undigested slurry, the nitrogen in digestate is more readily available as a plant nutrient.
• Smell - AD can lower the odour from farm slurries by up to 90%.
• Pollution - AD can lower the biological oxygen demand, (BOD - a measure of the polluting strength of a material) in the feedstock to less than 40% of that in the digestate. However, BOD of digestate is still extremely high relative to the discharge standards for wastewaters.
• Pathogens - pathogens in the feedstock, such as salmonella, are lowered by AD.
• Weed seeds - AD kills many weed seeds and hence there is less need for herbicides.
• Plant nutrients - management of plant nutrients is aided by mechanical separation of the digestate. Plant nutrients in the fibre fraction can be exported off farm as a soil conditioner, or further processed into granular organic fertiliser or combustible fuel.
• Handling - compared to raw slurry, digestate flows easier and requires less mixing before spreading.
And for more on others who are addressing the issue of dog defecation in public spaces, there’s an MIT student who developed a biogas system for a small park in Cambridge, MA. The student, Matthew Mazzotta, created the system as an art project that shows how dog waste is perpetually fueling a gas lamp in the park. Mazzotta’s project is called Park Spark.
With inventors like Gary Downie and Matthew Mazzotta working on the problem of poo, the day will come when you will not have to walk through the park and worry about stepping in anything squishy.