Thursday, August 20, 2009

Could Your Labrador's "Waste" Be The Fuel of the Future?

There's power in the poop. Real, usable, recyclable, non-fossil dependent, renewable fuel.

The city of San Francisco aims to stop using landfills by 2020 and as part of their research to figure out just how to manage that they're looking at using pet waste to produce methane gas for fuel. When you figure that a great deal of the pet waste in the heavily populated, pet friendly Bay Area ends up in landfills now, approximately 4% in San Francisco alone, using anaerobic digester technology to break it down and gain some energy production from it, even if only enough to help run the processing facilities, could make a significant dent in what's piling up at the dump.

The methane is produced in digesters, more correctly called anaerobic digesters. The process is inherently organic, using anaerobic (non-oxygen using) microorganisms to literally digest the waste materials, feeding off of the sludge, metabolizing it and producing their own waste -- the stuff we use for fuel.

The fuel produced by anaerobic digesters is “biogas,” composed of 50 - 75% methane, 25 - 50% carbon dioxide and, variably, trace amounts, singly or in combinations, of nitrogen, hydrogen, hydrogen sulfide or oxygen. The methane we burn, the carbon dioxide, theoretically, is not released directly into the atmosphere. If hydrogen sulfide (a consequence of sulfates in feed) is produced, though, being a toxic byproduct, it must either be “scrubbed” or inhibited at the beginning of the cycle.

There is some controversy, however, on how effective this idea is as far as reducing fossil fuel dependence, production of greenhouse gasses and reduction of solid wastes that we need to dispose of in some manner, as well as destroying pathogens carried in the waste. Some of the solids left do make excellent fertilizer, provided dangerous pathogens are destroyed. Not all digesters reach a temperature sufficient to destroy disease causing bacteria. Some methods of dealing with the solids left set up a composting step, breaking the solids down further so that they can be used as fertilizer. This is more applicable, though, to agricultural animal waste, as dog and cat feces carry some pathogens that are difficult to kill off, so that's a hurdle that must be leaped in order to make this plan to reduce landfill usage viable.

Composting has always been an accepted method to break waste materials down to useful, recyclable material. Thanks to those pathogens, though, it's more problematical when trying to deal with most pet waste. It should never be used near food producing ground, or where there is a high ground water table, so if producing biogas from pet poop is going to be a viable solution to the growing dilemma of how to get rid of the stuff sanely, an effective and non-prohibitively expensive method of rendering the nasties impotent before putting it to use is necessary.

Some individuals use composting at home to deal with their pets' waste, which, if they are unaware of the potential for disease causing microorganisms to survive the process, that rarely creates temperatures capable of killing these bacteria, can create a hazard not only for themselves and their own families, but for those who live nearby. If they use the stuff on their yards as fertilizer, and some of it gets washed away into the street, it then travels to the wastewater sewer system and finds its way out into the ecosystem, and even into water that winds up being used to water food crops. There was an outbreak a few years back of salmonella that contaminated green onion crops via irrigation water. People got sick. A few died. There are many ways for contaminants to find their way into places we don't want them to be; we need to be aware and careful of adding even more opportunities for these potential poisons.

Even using the last numbers of a “pet census” from 2005, pet waste is a problem that is growing exponentially: 90 million cats and 74 million dogs -- and those numbers are for pets; they don't include the animals in shelters and strays, but they have to do their business somewhere too. Whether or not this idea does all its proponents hope it will do, it is one more way to potentially dispose of pet waste rather than letting it pile up, and with the sheer numbers of pets in America alone, that could be a whole lot of manure to manage.

Provided by Betsy Miller of Where you can find great deals on Dog Kennels and Pet Doors.

Technorati Tags:


Blog Archive


  © Blogger templates The Professional Template by 2008

Back to TOP