Methanizable and Non-Methanizable Waste
Most of the wastes that we produce are methanizable. All substances coming from animal or vegetable world and that didn`t go through important artificial transformation is methanizable. For instance, the hydrocarbons are natural substances and are methanizable. The plastic materials created from the polymerization of those products are not methanizable. The molecular links artificially created by humans during the polymerization are too strong to allow any action to them by the bacteria. The methanization will take place in a water saturated environment, which is very efficient to treat liquid products. It can treat all the organic matter as fat, grease, sugar or protein.
The methanizable waste list includes:
- The fraction of domestic wastes considered to be organic
- Papers and cartons
- Wastes from kitchen and restaurant (schools, offices, restaurants, hospitals)
- Green wastes from residents, municipalities, industries, farms
- Organic wastes from supermarket or distribution channel
- Products not sold or bad products
- Over production of fruit and vegetable
- Effluents from animals : manures and others
- Wastes from food industry
- Green alga
- Flours
- Solid waste from waste water treatment plants
- Solid waste from industrial waste water treatment plants from food, pulp and paper, chemical, cosmetic, pharmaceutical, textile.
The potential of biogas production of the waste will depend on its concentration of dry matters and organic matters. Manure is very liquid (m.s: 4 à 5%) and have a low potential: 20 to 25 m3 of biogas per m3 of manure. Fats have a high potential where they can produce 700 to 800 m3 per m3. Some substances are not favorable: too much nitrogen in the form of ammoniac (concentration more than 3 g/l) or salt (concentration more than 8 g/l) can reduce the efficiency of the methanization process. It becomes essential to know the detailed waste composition that go in the digester. Laboratory tests are recommended to verify the digestibility of all wastes to be treated.
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