Anaerobic digestion in urban settings?
When we talk about using anaerobic digester technology to produce biogas from organic material, and then using that biogas to generate electricity, we’re usually talking about processing agricultural waste or manure out on some farm or rural facility. But what about the city? There’s thousands of tons of organic or “green bin” waste produced every day in cities like Toronto, and much of it still goes to landfill — particularly organics from multi-unit dwellings and industrial/commercial operations.
My Clean Break column this week looks at the idea of building a network of small anaerobic digester systems across a city where buildings/businesses that produce organic waste are clustered. The material can be collected locally (no long-distance hauling), processed locally, and the heat and electricity produced can be used locally to help make the urban grid more reliable.
Any thoughts?
Tyler Hamilton is a business columnist for the Toronto Star, Canada's largest daily newspaper. In addition to this Clean Break blog, Tyler writes a weekly column of the same name that discusses trends, happenings and innovators in the clean technology and green energy market. This blog is a personal project started in April 2005. It is not an official blog of the newspaper.
September 9th, 2008 at 9:10 pm
I’m all for it, especially in urban settings. I think part of the prob is that renewable energy is just too darn invisible; its either up on the roof, out in the windy grange, or as credits up in the towers of the Chicago. It goes against my tenets, but it seems adaptation measures might be a better way to alert the public that climate change is real and that some organizations, like municipalities, are busy preparing for it. For instance the building of levees, grade level cisterns, and rainbarrels. Evacuation drills, road closures while bridges are inspected and reinforced. People will see such actions happening right close around them since those actions will be aimed at protecting them and their homes, whereas mitigation can take place nearly anywhere so can easily be out of sight (except to readers of this awesome blog however!). No, no! I want mitigation first! Scientists tell us adaptation must occur, as we have already entered the event horizon, so maybe we need to push for that aspect more than we have been. Maybe adaptation is a gateway for our collective conscience?
September 10th, 2008 at 12:14 am
Interesting read from your Clean Break Column- I would think there are a couple if problems. First is the cost- there are economies of scale you lose with smaller plants- it would be interesting to see where a tipping point is with the cost of the plant vs the cost of energy. And how hard it is to extract that energy. For example, is it harder to extract energy with this type of mixed waste vs the energy retrieved from a dairy farm, which is just dealing with one type of waste. Also, for the trash that you don’t to mix with the waste you are trying to convert- that still has to be picked up and dealt with, so now you may be spending more with two separate collection systems.
Don’t get me wrong- I am all for this type of waste reclamation, and hope that it becomes widely implemented- just asking questions about its current viability with a city environment. After all, it is not just about the short-term cost of implementing such systems, but considering the long-term benefits as well- but convincing people to spend money now for long-term benefits is, unfortunately, a hard sell most of the time. Perhap, though, this is changing (but don’t listen to me, I am an optimist;-)
September 10th, 2008 at 11:23 am
To Paul C,
As Yield has been developing its business its great to see the number of optimists that have lent support & encouragement to our urban anaerobic digester (AD) initiative, thanks!
Back to your comment, manure though consistent has actually got a relatively low energy content when compared to that of the mixed urban organic wastes that we will be using. The challenge with the urban organics (think out of date packaged food products, yard/garden/kitchen waste etc.) as you pointed out is how do you separate the “good stuff” from the plastics, glass, wood etc. Yield Energy has a partnership with an innovative company out of Europe that has developed a great cost effective way of taking in mixed waste streams and squeezing out 99% of the organic content which can then be used to feed the AD.
BTW, by being able to deal effectively with these urban organic wastes we don’t need to create a new collection system, we as a society just need to point the current collection trucks towards these urban AD facilities rather than the ever congested landfills.
September 10th, 2008 at 5:25 pm
Good Day Rolfe, How about growing algae then processing them for their lipids, as Dr. Dennis M. Bushnell, Chief Scientist of NASA’s Langley Research Center, is touting. (An interview with Dr. Bushnell is posted on Radio Ecoshock, (ecoshock.org) the 080808 program)
September 11th, 2008 at 1:40 am
Thank you Mr. Philip for your insights- this answers quite a bit for me about the differences. I did have one more question- and I compare this to what (very little) I know about reclaiming energy from cow manure, and use it only as a reference point. I was happilly surprised to hear that the energy content from what y’all will collect is higher, but I would think it is probably also harder, and therefore more expensive, to collect than cow manure- so can y’all produce the same amount of energy at a similar cost, or does it cost a bit more (of course, less would be even better;-)? And if so, what is the break-even point? For example, the one dairy farm I read about would have the system pay for itself- and now my memory fails me!- after 10-12 years I think. Of couse, doing this in an urban setting is even newer than for dairy farms, so I know some of what y’all have to project in the way of costs is probably still a bit fluid (no pun intended;-), so I will not hold you to any estimate you can share.
Again, thanks for taking the time to add your expertise to this blog, and good luck with your venture!
January 12th, 2009 at 3:02 pm
I’m all for this idea, the only problem is how to get the stone rolling. I’m actually researching anaerobic digesters and I need some ideas on how to build a small scale digester.
January 12th, 2009 at 4:30 pm
I like your article. I stumbled upon it doing some research for my thesis. I’m currently working on a project involving anaerobic digestion of food waste to produce energy in an urban environment in Montreal and I would like to ask you a few questions/share some information. Please email me back. Thanks!
March 17th, 2009 at 2:02 pm
I think the main barrier to this idea would be NIMBYism. I’m an engineer and did a post graduate degree looking at anaerobic digestion. A lot of projects in the GTA involving anaerobic digestion at water treatment plants are usually opposed because of the “ugly” structures required for anaerobic digestion. This usually involves very large steel globes. Otherwise, great idea.
April 8th, 2009 at 4:03 pm
Hi Tyler,
After reading some of your columns, I sent an email to your star address regarding the recent RFP from the Metro Zoo. Any leads you can provide would be appreciated!
Cheers,
Alan
October 29th, 2009 at 9:38 am
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