The electrical energy available in one cow's daily manure contribution could power a 100-watt light bulb for a whole day.
Biogas, also sometimes called "renewable natural gas," is fuel created by the anaerobic digestion of organic, biodegradable materials, like wasted or spoiled food, plant clippings, animal manure, meat trimmings and sewage. The anaerobic digestion process is carried out by naturally occurring bacteria that thrive in environments with low oxygen levels (hence the name "anaerobic"), like at the bottom of land fills. These helpful anaerobic microbes produce a methane-based gas which can be used for a number of purposes, including heating and cooking. Though it may not be as productive and efficient as the larger-scale ones, you can make your own cooking gas-producing anaerobic digester attached to a burner that works on the same principles as the professionally made digesters using this design created by the non-profit organization, GreenLearning Canada. Does this Spark an idea?
Instructions
Building the Biogas Collection System
1. Cut your 40 cm copper tube in half and sand down the sharp edges with sandpaper.
2. Insert one end of the tube into the sleeve of the Mylar balloon so the tube sticks about 2 cm into the balloon chamber.
3. After testing to make sure air can enter and exit the balloon freely by blowing through the tube, tightly tape the neck of the balloon to the tube to make an airtight seal.
4. Drill a hole through the center of the cork stopper, deposit a few drops of hot glue inside and around the hole and insert the 1/4-inch T-adapter by the stem.
5. Screw the two barb fittings onto the ends of the ball valve and tighten them with an adjustable wrench.
6. Cut two 25 cm pieces from your vinyl tube. Attach one to each end of the barbed T-adapter.
7. Attach the barb fitting of the ball valve to one side of the T-adapter tubing and to the other, push the free end of the balloon's copper tube inside the tube. Secure it tightly with a generous wrapping of tape.
8. Attach the remainder of your vinyl tubing to the free end of the ball valve and connect it to your Bunsen burner.
Preparing and Adding the Fuel
9. Using your wide-mouthed funnel, slowly scoop small amounts of the manure into the neck of your 18 ltr. plastic water drum with your wooden dowel stick. This would be a good time to wear your rubber gloves.
10. Add enough water to fill up the drum almost to the top, leaving just a few inches below the neck.
11. Use the dowel to mix up the water and manure mixture to release air bubbles.
12. Insert the cork of your T-adapter set-up into the water drum's cap attached to the neck of the water drum and make sure it fits tightly. Also make sure the ball valve is in the closed position.
13. Clean up with soap and water.
The Gas Production
14. Place the system in a warm place (between 80 degrees Fahrenheit and 100 degrees Fahrenheit is ideal) to help speed up the bacteria's digestive processes. On top of a radiator works, as does in a consistently sunny window, though if you choose the latter, wrap the jug in black plastic or construction paper to inhibit photosynthetic algae from growing and taking away from the fuel available to the fuel producing microbes.
15. Wait a few weeks for the aerobic bacteria to use up the existing oxygen in the apparatus and then die out so that the anaerobic bacteria will then begin to prosper and monopolize the biogas fuel.
16. Watch for the balloon to begin inflating, usually after about a month.
17.Open the ball valve as well as the valve on the Bunsen burner. While having a friend gently squeeze the balloon, use a match or spark igniter to light the burner, and you should have a small gas burning stove for cooking.
Tags: ball valve, make sure, water drum, anaerobic digestion, balloon tube, Bunsen burner, copper tube