Various types of sewage are always available, especially in residential areas and animal husbandry centers. Raw materials can also be obtained from agricultural waste, in the form of crop residues and wild plants. However, each raw material has a certain value that you must determine its type, both based on economic value and its ability to produce biogas. Here are some types of raw materials that can be used for biogas.
1. Livestock waste. Dirt from livestock, such as cattle, buffalo, goats, and chickens can be made as raw material for biogas. One cow from 400-500 kilograms can produce 20-29 kilograms of manure.
2. Agricultural waste. The rest of the crops, such as rice, wheat, soybeans, palm oil, and cassava can be used as raw material for biogas. Then, the former can be used as compost for soil fertility.
3. Water waste. Aquatic plants, such as water hyacinth, seaweed, and algae have good characteristics to be used as raw material for biogas. Water hyacinth is very appropriate to use, because it often becomes a weed in water areas, such as swamps and lakes.
4. Organic waste produced from households, markets or industries can also be processed into biogas. The manufacturing process can be integrated with compost production so as to get two benefits at once.
5. Human waste that has not been widely used can actually be used as raw material for biogas. In fact, with a lower C / N content than livestock manure, it makes it easier for fermented human waste to produce biogas more quickly.
The process of making biogas with the following steps:
1. Mix cow dung with water until mud is formed at a ratio of 1: 1 in a temporary container. The shape of the sludge makes it easy to get into the digester
2. Drain mud into the digester through the intake hole. At the first filling the gas valve above the digester is opened so that entry is easier and the air in the digester is forced out. In this first filling, cow dung sludge is needed in large quantities until full digester.
3. Add a starter (many sold in the market) of 1 liter and fill the fresh rumen of slaughterhouses (RPH) of 5 sacks for a capacity of 3.5 - 5.0 m2 digester. After the digester is full, the gas faucet is closed so that the fermentation process occurs.
4. Dispose of the first gas produced on days 1 to 8 because what is formed is CO2 gas. Whereas on the 10th day until the 14th day new methane gas (CH4) and CO2 began to decrease. At the composition of 54% CH4 and 27% CO2 the biogas will ignite.
5. On the 14th day the gas formed can be used to light a fire on a gas stove or other needs. Starting on the 14th day, we can produce biogas energy that is always renewable. Biogas does not smell like the smell of cow dung. Furthermore, the digester continues to be filled with cow dung sludge continuously so that optimal biogas is produced.
Processing livestock manure into biogas in addition to producing methane gas for cooking also reduces environmental pollution, produces solid organic fertilizer and liquid organic fertilizer and more importantly is reducing dependence on the use of non-renewable petroleum fuels