Biogasis a technology that forms energy by utilizing wastes. Such as agriculture,farm, and human waste. Other than being an alternative source of energy, biogascan decrease environmental issues such as pollution, air, and soil. Biogas isone of the alternative energy that commonly used by many people. Biogas itselfis produced by the bacterial decomposition and a mixture of carbon dioxide (CO2)and methane (CH4).
The most efficient biogas for stablecontinuous digestion process is the biogas that produced at the temperature of310 K and contains 65% of methane. Biogas is produced with the help ofmethanogenic or methanogen bacteria. These bacterias are naturally present inwastes containing organic materials, such as organic waste and manure. Biogas can be used forheating, electricity, and many other operations that use reciprocating internalcombustion engine. Biogas can be produced from any raw ingredients such asagricultural waste, manure, and food waste.
On 1980, China has built over seven million units of digester to produce biogas from any waste materials such as agricultural waste, and in India as well. These two countries have been developing biogas for a very long time. They developed biogas because they did not have natural energy sources, so they use agricultural waste as a substitution. Tofu waste is one of the ingredients that can be used for producing biogas. A digester is needed in order to produce biogas from tofu waste.
There are two types of digester generating device to produce biogas; the floating type and the fixed dome type. The fixed dome type is a digester that form an air-free hollow dome and made by digging the soil. The floating type is a well-shaped digester that have an iron cover above to collect gas from the digester. In the digester, the methane bacteria will process the tofu waste into biogas which is then channeled through the pipe and collected in the gas cylinder.
The gas cylinder, which contained these biogas, can then be flowed to the stove for cooking purposes and others. Biogas comes from a mixture of tofu waste, water, and residual plants such as straw. The initial gas is produced for 2-4 weeks. The waste from the process, which was called slurry, can be used as an organic fertilizer such as compost to fertilize plants.
These type of biogas is suitable to developed in areas that have a lot of biomass, for instance in the food production center and livestock such as Central Java, Eastern Java, Bali, South Sulawesi and other areas that have a lot of biomass (Iqbal, 2015). The process of making biogas from tofu waste are (Iqbal, 2015):1. Prepare 200 liters of liquid waste from the tofu making and pour it inside a container and let it cool.
2. Pour the liquid onto a container which has a hole that connects to another hole to fill in the digester until it is full.3. Let the fermentation process work for at least 30 – 45 days to create good quality gas.4. To check if the gas has been formed or not, turn on the faucet that is connected to a stove and turning on the stove as well. If the stove is lit, means that the fermentation process has succeeded turning into biogas, and ready for multi purpose usage.
5. For everyday usage of biogas, keep adding waste ingredients everyday. Somethingdisgusting is also can be used for producing biogas. Animal waste can be processedinto manure, which gives advantages for environment. Animal manure is used as oneof the sources that can be produce as Biogas. Many people commonly use thistype of biogas. In Turkey, animal manure is widely used as fuel for the houses.They used dried cow dung as the ingredient for fuel, which is a classicalmethod.
But, this method causes high-energy loss. However, the fermented animalmanure, which is bio-fuel, is more valuable and Turkey has already used themethod. Boysan (2015) estimated the potential of biogas in Turkey is 4 billionmeter cubed/year and it is equal to 25 million kWh. Bio-fuel is produced fromthe anaerobic fermentation of carbohydrates in manure by bacteria. It is manly composedof methane, with some carbon dioxide and other trace gases. Biogas can be madefrom simple materials on a small scale in a digester. Biogas can also beproduced on a large scale if the bigger digester is used. The materials that contain carbohydratesare fermented by anaerobic bacteria and turns carbohydrates into biogas.
Theremaining materials that settle to the base of the digester can be used as afertiliser. These types of biogas generator are most commonly used in thedeveloping countries. These type of biogas is also suitable to develop in areasthat have a lot of farms, such as, Central Java, Eastern Java, Sumatera and Sulawesi. Other than agricultural waste andanimal waste, biogas can also be created from something that we consume, whichis food. Food that is produced everydayto fulfill human needs, also produces left overs or food waste. Food waste ororganic waste is one of the ingredients to make biogas. The examples of foodwaste that can be used for producing biogas are the stem from a water spinach,the outside skin of a garlic, leaves, and other unused kitchen ingredients,which are organic wastes that can produce gas.
Besides that, a research byWardana (2012) about biogas has also shown that left over rice, chili, andother kinds of foods can also be affective on producing biogas. The next stepis to prepare a cow’s rumen, which makes the process faster, that will be mixedinside a reactor that called biogas tank. Water is also added to the process.The steps on forming the gas/biogas are hydrolysis, acidogenesis, acetogenesis,and methanogenesis.
Hydrolysis, which is the first step of anaerobic digestion,is a chemical decomposition in which a compound is split into other compoundsby reacting with water. Acidogeneis is a biological reaction that convertvolatile fatty into volatile fatty acids. Acetogenesis is a biological reactionthat convert volatile fatty acids into hydrogen, carbon dioxide, and aceticacid. Methanogenesis is a biological reaction that convert acetates into carbondioxide and methane, while hydrogen is consumed. In conclusion, there are a variety of ingredients thatcan produce biogas. Biogas is formednaturally due to the bacteria anaerobic process that breaks down the garbage.
The methane normally escapes into the atmosphere and it contributes to global warming.So, to reduce or to prevent the contribution of methane to global warming, theexperts made an equipment to collect the methane and prevent the methaneescaped into the atmosphere. Thecollected methane gas can then be used as an electricity, cooking gas, or a heaterfor buildings such as homes, hospitals, and schools.