BIOGAS — An emerging alternative technology

Energy plays an important role in the development of any society. It is the primary and universal necessity for all kinds of work ever done by human beings and nature. The rapid industrialization has led to increased use of fossil fuel such as coal, oil and gas to meet the power requirement, which results in depletion of natural resources. Due to increased demand and cost of energy, these resources are not sufficient and becoming more and more expensive. Presently, the country is facing major energy crisis that has seriously affected economic growth and development process. Prolonged load shedding is a routine matter and the reason is continuous decline in oil and gas reserves and vertical increase in prices. Deforestation and emission of hydrocarbon is a continuous threat on environment, considered responsible for ozone depletion. With the increasing fuel demand, available energy sources are not sufficient as being used rapidly. Emission of poisonous gas from burning of fossil fuel is also a major concern for the ecosystem and human health. In view of the prevailing situation it is necessary to get rid of these serious problems.
For this purpose, alternate energy sources especially for rural community must be explored. It is becoming difficult for the Government to provide gas facility even in cities, what to talk of villages. Our country is rich in animal resources, water, construction material, ambient temperature and human resources. The increased power demand, depleting fossil fuel sources and increasing environmental pollution have led the world to think seriously for alternative sources of energy. The concept of alternative energy relates to the sustainable, renewable and pollution reducing energy. The available options for renewable energy in the country are Nuclear, Wind, Solar and Biogas.
Use of renewable biomass as energy source, creates a balance to atmospheric carbon dioxide levels through replacement of fossil fuels. Biogas originates from bacteria in the process of bio-degradation of organic matter under anaerobic conditions. In the absence of oxygen, anaerobic bacteria decompose organic matter and produce a gas mainly composed of methane and carbon dioxide called biogas. This gas can be compared to natural gas, which contains more than 80% methane. Compared to other fossil fuels, methane produces less atmospheric pollutants and generates less carbon dioxide because it is comparatively a clean source of fuel. The trend has increased to use it for appliances, vehicles, industrial applications and power generation. Analysis of biogas shows that it contain Methane 50- 75%, Carbon dioxide 25-50%, Nitrogen 0-10%, Hydrogen 0-1%, Hydrogen Sulphide 0-3%, and Oxygen 0-2%, quite nearer to the natural gas, having good combustibility. Faced with power and diesel shortages, farmers are not able to optimally benefit from water resource which is further deteriorated with increasing stress from climate change. Use of biogas is a good option to run the existing tube wells, which are presently using diesel oil. Keeping in view this technological advancement and attractive financial breakthroughs it should be implemented in suitable villages to meet continuously increasing water requirements of agriculture.
A typical biogas plant consist of a digester where the anaerobic fermentation takes place, a gas holder for collecting biogas, and input-output units for feeding the organic matter and storing the effluent respectively, and gas distribution system. The fermentation of cow dung and farm waste in biogas plant in the form of slurry increase nitrogen, phosphorus and potash percentage.
Geographical suitability of Biogas Plant: The process of organic material anaerobic digestion takes place in three main temperature ranges: from 10-25°C, from 30-37°C and from 48-55°C. The ideal temperature is between 30 and 40 degrees Celsius within the fermentation chamber, as this is the temperature range at which anaerobic bacteria are most active. If the temperature is too low, the process of fermentation will become slow; consequently biogas production will be reduced. Punjab is the most populous region with 56% of total population. Moreover, the central Punjab including Faisalabad, Sargodha, Jhang, Toba Tek Singh, Sahiwal, Okara, Pakpatan, Sheikhupura, Hafizabad, Mandi Bhauddin, Khushab, Mianwali, Bhakar is considered to be the most potential area for installing biogas plants as these areas are temperate in nature. Northern areas of the country are less temperate, so their suitability for installing biogas plants is low.
The digested liquid manure coming out of the biogas plants would provide an excellent organic manure in which all the useful nutrients remain preserved (due to decomposition in the enclosed digester of the biogas plant) for promoting environmentally sound eco-farming. Because the nutrients in the biogas digested liquefied manure gets mineralized, and is easily available to the crop. Moreover, this biogas digested manure, improves water-holding capacity of the soil, and acts as soil-conditioner, improving its fertility and building-up micro-flora in the soil (which might have lost due to excessive use of chemical fertilizers & pesticides. Due to the residual effect of the biogas-digested manure on the soil, its positive impact could also be observed in the next 1-2 crops as well. As the biogas-digested manure provides all the plant food, minerals and micronutrients, it produces healthy crops, due to which the attack of insects and disease is reduced substantially. As the inherent strength of the plants (crops) is developed, it increases the capability and capacity of crops to fight back the diseases and also to withstand under worst stress conditions and water shortage, as compared to the chemical fertilizer based crops. If the farmers are not able to use the biogas plant digested liquid manure immediately, they could use this liquid for making excellent scientific compost along with other locally available biodegradable wastes. The digested liquid manure would also promote making of compost faster, and all the nutrients of the manure will remain preserved when composting rather than letting it dry- this compost could then be used during the crop seasons. In developing countries, the production of biogas and bio-fertilizer holds the promise of substituting increasing amounts of imported fossil fuels and mineral fertilizers. On an economic scale, the importance of digested sludge as a supplementary source of fertilizer is gradually gaining recognition. As populations continue to grow, there is a corresponding increase in the demand for food, fertilizers and energy. In Pakistan, both the production and consumption of chemical fertilizers have been steadily expanding over the past decades. According to an estimate it is predicted that the national consumption of mineral fertilizers could be reduced by 30% through the use of digested biogas sludge as fertilizer that improves soil fertility and increased crop yield by 10-20%. Furthermore no smoke is produced by burning the biogas, residential area remained neat and clean and a germ free environment is available besides the economic advantages.
Biogas is cheap, clean, soot free and extremely convenient cooking fuel. Introduction of this technology to the rural community will help to mitigate the daily cooking problems of rural women, upgrade their living standard, improve the environment and slow down the migration to urban areas. Energy efficient devices can help to create a sustainable fuel system within the rural community and sustain the ecological balance of a region. Alternative energy sources can provide local employment opportunities through construction, repair and maintenance of energy devices, or through the sale of energy to local utilities. This technological advancement through further expansion in the rural community as necessity of life can save the living planet from environmental pollution. It is the dire need of the day that other resources must be explored for self sufficiency in energy as well as agriculture sectors. These days, the technique of producing biogas from agriculture, animal and domestic waste is getting popular throughout the world, to meet the energy crisis, shortage and increasing cost of fertilizers.
Based on the quantity of gas produced and number of animals available, three different sizes of biogas plants are being designed. Plant size of 12 cubic meters for which 6-8 animals are required, can produce the amount of gas which is sufficient for 10 to 12 hours of domestic use. 30 cubic meter plant with 16-18 animals can produces gas for 24 hours for domestic use. Similarly, 50 cubic meter size of biogas plant with 28 animals can produce domestic biogas for 24 hours and 8 to 10 hours tube well running.
To facilitate the rural community for adopting the biogas technology and its promotion, Zarai Traqiati Bank Limited has made it a loan able item for house hold & tube wells. The farmers, who have sufficient number of animals, can contact branches of Zarai Traqiati Bank in their respective areas or may contact Agriculture Technology Department, head office Islamabad (Phone No.051-2840872, 0301-5139165, Fax 051-2840848).