A Dung Deal: Power From Poop

by Lloyd Alter, Toronto on 07.25.08
Science & Technology (alternative energy)

Larger version of illustration at Globe and Mail

At a properly run farm, "nothing is waste. Everything is a resource. It's just a matter of harvesting." With 750 cows, Laurie Stanton's farm has a lot of manure to harvest. Martin Mittelstaedt writes in the Globe and Mail about Ontario's largest farm-biogas installation. It seems like the perfect solution to a big problem; there are only so many places to put the 50 million tonnes of "biomass", as it is politely called, that is produced each year in the province. Instead, it is fermented in a big tank, and the methane is collected and piped to a diesel generator. The leftover liquids make a good fertilizer and the solids become bedding for cows.

It is about time; in Germany, biogas produces as much energy as a large nuclear plant; here we just build mountains of manure.

From the Globe and Mail:

HOW WILL IT WORK

The province announced funding for a $5-million anaerobic digestion power plant at Laurie Stanton's dairy farm in the hopes that it will suggest a way of dealing with some of the nearly 50 million tonnes of biomass, or waste residues from plants and animals, that Ontario produces annually. If successful, Mr. Stanton's farm will produce about 1.3 megawatts, enough to power about 800 typical homes.

1. BARN: Slurry of manure is washed and scraped from cow stalls into a series of sewage pipes that run under the barn. The manure is mixed with other food wastes.

2. DIGESTER: The slurry is heated to around 37 degrees and kept at that level for the five days needed for the microbes to decompose the cow dung. This process gives off methane gas, which bubbles through the slurry and is collected at the top.

3. DIESEL GENERATOR: The gas runs to the generator, where it is burned to produce electricity to power the digester and the farm, and to feed into the grid.

4. SOLIDS SEPARATOR: Leftover liquids are used as fertilizer and the solids are strained to make a material to be used as bedding for the cows. ::Globe and Mail

More on Biogas in TreeHugger
Cow Poop -> Electricity: Biogas Project in California
Human Poop and Urine Provide Cheap Biogas Source in Uganda
Bio-Digesters in India: Nothing Wasted, A Lot More Gained
Bioenergy in Yunnan, China Video Podcast
Biogas Plant in Eastern Germany Will Be the World’s Largest

Thirsty for more? Check out these related articles:
Will Allen: "Industrial Agriculture One of Most Polluting & Dangerous Industries"
Expanding Waste-Based Renewable Energy
The Biggest Threat to the Democrats' Climate Bill: Democrats
Aktivhaus Generates More Heat and Power Than It Needs

Bokashi Composting

Bokashi is a ramped-up, high-speed composting method first developed in Japan. What gives it the muscle that ordinary compost lacks? Think of the difference between wine and grape juice, and that’s the key to a fine bokashi.

» See also: Recycling Our Way to a More Sustainable Future
» Get CleanTechnica by RSS or sign up by email.
Fermentation and Bokashi
Conventional composting relies on oxygen-fed organisms to break down organic material. Bokashi uses different kinds of microbes that thrive without oxygen. They decompose organic matter through an anaerobic process. It’s basic fermentation, the same process that gives us wine and pickles.

Advantages of Bokashi Compost
Bokashi works fast - in a matter of days, not months. And, when properly managed, bokashi is practically odorless. That makes it ideal for apartments and other small dwellings. Compared to sink disposals, bokashi or “bucket composting” also promises to save water and reduce the load on sewage treatment plants.

Bokashi is also highly scalable. Larger buckets can be fitted with wheels to ease transportation logistics. For restaurants or schools, prisons and other institutions, bokashi has potential as a speedier, more space-efficient way to recycle large volumes of kitchen waste into valuable compost.

How to Do Bokashi Compost
Making bokashi compost is simple. You need a couple of big containers with tight-fitting lids (to keep the oxygen out), some kitchen scraps, and bokashi mix. The mix contains wheat bran, molasses, and EM’s - the efficient microorganisms that drive the process. DIY bokashi help is available online but if you want to get started quickly, you can find ready-to-go bokashi kits at many gardening and eco-shopping sites like gaiam, or at specialty suppliers like Bokashicycle.