Wednesday, September 13, 2017

Anaerobic Digestion of Dog Poop Fuelled a Pacific Park Lamp - What Now?

The story of anaerobic digestion of dog poop which at first simply lights a park lamp, but can do much more in future, is a fascinating story for its use in anaerobic digestion, to both render it harmless by providing soil improver/ a fertiliser after pastuerisation, and an energy source (methane biogas).

To demonstrate this fact we have put together some of the articles on the subject which are available on the internet.



If you are like many people you will be reading this with disbelief, and we don't blame you. 

How could all that smelly dog poop which is such a high disease risk, especially for children, possibly become a substance which can be useful?

Our video will explain this. Watch our video below:


Note: The video says click the link below, but there is no need to click any links, because you are already here, on the full article page!

The answer is through using the anaerobic digestion process in a new and very simple low-rate low temperature biogas digester, huge new possibilities emerge. Unfortunately, uptake for new parks, seems to have stalled as we explain below, but the idea is interesting.

First, let us look at the typical research which confirms the potential of dog poop to feed anaerobic digestion plants.

It confirms that there is both plenty of it that is now being collected, and when blended with certain other biomass (for example grass mowings), there is a synergy that is very productive:

Comparative Study of the Potential of Dog Waste for Biogas

The potential of dog waste to produce biogas and/or enhance the biogas productivity of some other animal and plant wastes was investigated.

From the trials it was concluded that... dog waste can be a source of biogas and a source of catalyst for prolonging the retention time of other waste samples such as field grass and cow dung.

The result of the proximate and microbial analyses reveals that dog waste has high potential for biogas production that even though its quantity may be small, it is a good blend for other waste types such as field grass and cow dung. via Comparative Study of the Potential of Dog Waste for Biogas

But, how much dog poop is available?

6,500 tons of dog poop is produced in the San Francisco alone... Local authorities do provide dog waste ... Yard waste and food scraps can go through the same biogas ... via Dog Poop Power For San Francisco

So, the problem of dog poop exists, there is lots of it, and there are researchers that say anaerobic digestion will work, but is it already being digested? Is it being digested in biogas plants anywhere?

The simple answer is, yes it is, in a number of cities. An example is described in the article excerpt below, about Waterloo Council in Canada

Dog waste anaerobic digestion scheme for Waterloo, Canada

(2012) The city of Waterloo in Ontario, Canada, will soon be home to a dog waste biogas facility, according to the Huffington Post. Dog waste from around the city will be collected and turned into energy using anaerobic digestion. It will be one of the first times such a program has been used in a Canadian city. 

Although already popular in smaller Canadian towns, dog waste anaerobic digestion has yet to be tested in a city of Waterloo’s size.

Special ‘receptacles’ will be set up around the city which dog owners can put their dog’s waste into instead of a regular litter bin. The dog waste bins will be bright green, with a dog-shaped opening.

"It's actually a big issue, dog waste. If you look at our municipal litter bins ... it's 40 to 80 per cent dog waste,'' Waterloo mayor Dave Jaworsky told the Huffington Post. The city has a population of about 100,000 people.

After being stored underground for ten to 14 days, the dog waste will be vacuumed out and sent to a processing plant outside the city, where it will be used to create biogas for heat and energy. Any surplus will be used for fertiliser. ... via Dog waste anaerobic digestion scheme for Waterloo, Canada

Ah! Those Canadians can do it, but it is probably highly subsidised you say, given that this example is in Canada.

But let us tell you that this works at many different scales, and at a low rate in the following example:

Dog Poop Has Bright Side: Powering a Park Lamp

It stinks and it's a hazard to walkers everywhere, but it turns out dog poop has a bright side. Dog poop is lighting a lantern at a Cambridge dog park as part of a monthslong project that its creator, artist Matthew Mazzotta, hopes will get people thinking about not wasting waste.

The "Park Spark" poop converter is actually two steel, 500-gallon oil tanks painted a golden yellow, connected by diagonal black piping and attached to an old gaslight-style street lantern at the Pacific Street Park.

After the dogs do their business, signs on the tanks instruct owners to use biodegradable bags supplied on site to pick up the poop and deposit it into the left tank. People then turn a wheel to stir its insides, which contain waste and water. Microbes in the waste give off methane, an odorless gas that is fed through the tanks to the lamp and burned off. The park is small but has proven busy enough to ensure a steady supply of fuel.

Dog owner Lindsey Leason, a 29-year-old Harvard student, said she was all for seeing poop in a new light as she watched her two dogs play at the park. ... via Dog Poop Has Bright Side: Powering Park Lamp

Oh! But, this is only playing at producing methane, the doubters would say.
So, let us provide another article in which this is reported again as working:

Dog poop methane digester turns waste into biogas

City parks confronted with dog waste hope to turn the nuisance into a usable source of biogas. With the  "Park Spark" poop converter is actually two steel, 500-gallon oil tanks painted a golden yellow, connected by diagonal black piping and attached to an old gaslight-style street lantern at the Pacific Street Park.

After the dogs do their business, signs on the tanks instruct owners to use biodegradable bags supplied on site to pick up the poop and deposit it into the left tank. People then turn a wheel to stir its insides, which contain waste and water. Microbes in the waste give off methane, an odorless gas that is fed through the tanks to the lamp and burned off. The park is small but has proven busy enough to ensure a steady supply of fuel.

Dog owner Lindsey Leason, a 29-year-old Harvard student, said she was all for seeing poop in a new light as she watched her two dogs play at the park.

Dog poop methane digester turns waste into biogas - YouTube via Dog poop methane digester turns waste into biogas - YouTube

We agree that to show that municipal authorities in wealthy cities are digesting dog poo successfully, may be one thing, but large scale take up of dog poo as a "green" energy source will not begin until businesses can do this, offer to take dog poo, and make money with it.

That's why the Pacific park lamp articles are so interesting.

Unfortunately, the park lamp biogas idea does not seem to have withstood the test of time.

A company in Wales, UK, which was promoting the method in the UK, as shown by the following article, is not actively promoting this any longer on their website.
Back in 2012 they were reported as below:

Welsh Company Streetkleen Taps Dog Waste for Renewable Biogas

A business model for dog waste-to-biogas
The waste-to-lamplight stations are ideal in terms of public awareness and they could raise some opportunities for revenue from corporate sponsorships, but the real meat of Streetkleen’s business plan will be a network of Streetkleen waste disposal receptacles that come complete with biodegradable waste bags.

Under contracts with local governments, the waste would be picked up regularly and taken to a commercial scale digester facility.

Assuming that dog owners tune into the new system and use the special dog waste receptacles instead of putting the waste in with mixed trash, that could add up to quite a bundle. In the U.K., an estimated 1 million dogs generate about 1,000 British tons (tonnes) of waste every day.

In the U.S. the economy of scale could really kick in. According to an ASPCA estimate, there are more than 1.5 million dogs in New York City alone.

For that matter, dog waste removal is already starting to turn into a business opportunity, in the form of pet waste removal companies that serve homes and private companies, so it’s not a stretch to apply a similar model to municipal pet waste removal.

Local governments would pay for the service, but at least some of that cost would be offset by diverting tons of heavy, soggy waste out of the general stream that would otherwise go to incinerators or landfills.

Dog poop methane digester turns waste into biogas - via Welsh Company Streetkleen Taps Dog Waste for Renewable Biogas

The park lamp biogas method articles stop in 2013, so clearly a problem has occurred with this business model.

Nevertheless, dog poop biogas production is moving forward now that there are many more anaerobic digestion food waste plants which can accept this waste for co-digestion with the food waste.

Plus, Streetkleen was promoting a fascinating, and highly innovative business model, no matter what the outcome.

Local authorities in the UK who are sending dog poop to landfill will be being charged at a cost of about GBP100 per tonne, so there is money to be had from accepting dog poo in anaerobic digestion plants, with suitable waste management licenses.

If anyone reading this knows about the current fate of any of the park lamp biogas plants we would love to know what has happened since 2013? Are the original lamps still biogas lit?

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