(1-1)Energy for cooking


It is well known that organic materials produce biogas after anaerobic activity. This process is utilized by our septic tank(EMG by Ozeki), and the resultant biogas is used for daily cooking. The biogas consists of 60% methane and 40% carbon dioxide and the energy requirements of cooking for twelve days can be obtained from one month's amount of bodily waste. The biogas producing system at the site is shown in the next figure. The tank is filled with water and can be used at any time.

The biogas system with septic tank(EMG,Ozeki)

The amount of water used in a normal toilet is too much to allow biogas to form. A marine toilet is used in the house which flushes 280cc of water a time. This amount of water is not enough to create biogas and so a seat with a water sprayer has been attached. This decreases the use of toilet paper which uses energy to produce, and also creates pollutants during its manufacture. Bodily waste and garbage from the kitchen are taken to the first section of the tank where, after an aerobic process, the sunken material moves to the next section along the slope. There biogas starts to be produced by methane bacteria which can be active above -20�Ž. In this section the biogas is stored and from there passes through a deodorant filter before reaching the cooking range in the kitchen. Pressure is monitored on a gauge which usually shows from 8kpa to 13kpa depending on the amount of input. There is little residue, but in order to allow inspection of the water level, the third section of the septic tank has a manhole. An important feature of this system is that all organic materiai is changed into biogas. Currently organic exhausts are burnt or dumped in rivers or at sea. The former process wastes a lot of energy and the latter damages the river or the sea with too many rich nutrients.


The efficiency of photosynthesis is said to be about 4.6�`4.7%. Bodily waste contains a lot of energy which should not be wasted. This form of exchanged energy from the sun can be a reliable energy source as long as human beings exist. At transport hubs, for example airports and train stations where many people gather, not only bodily waste but also leftover food waste is produced in large quantities. These kind of materials can and should be used as energy sources. The carbon dioxide after burnning it can be cleaned with photosynthesis and be used for growing greens as it will be mentioned later.