BIOGAS-AN OVERLOOKED SOURCE OF ENERGY
DUNG FERMENTATION LEADS TO GAS, ELECTRICITY, AND FERTILIZER
TARIQ AHMED SAEEDI - email@example.com
June 15 - 21, 2009
Biogas is an emerging mode of creating energy sources in developing countries, though in developed and reasonable numbers of developing nations this alternative source is exploited to satiate rising demands of electricity and gas of industries and households. While modern technologies are bolstered in capital-rich economies to recycle and transform bio wastes, for example, produced in form of manure in to fuel, low-income countries are still using traditional ways to extract alternative source of energy out of non-edible materials accumulated in cattle and agriculture farms.
Amidst mounting crisis of energy, a shift in world's attention towards biogas as a substituted energy source is timely. Produced through cattle composts, biogas has become a contoured replacement of natural gas and hence it is popularized as fuel to generate electricity. Of dual advantage biogas provides unconventional fuel and dung fermented to excrete gas can be processed in to organic fertilizer. Besides, recycling of wastes before draining out alleviates multipronged costs of pollutions. In Pakistan with substantial numbers of livestock, this source contributes negligible portion in the total energy mix despite the fact that costs of installation of biogas plants are offset immediately by two outputs: gas and organic fertilizer. In many rural areas, where firewood is consumed, biogas use can alleviate deforestation.
Further, a popular disquieting low productivity of Pakistan's buffalos and cows can be compensated through biogas recovery. Pakistan has 31 million buffaloes, 21 million cows, and other cattle. However, the country largely depends on buffalos for production of milk. It is said that milk productivity of this indigenous herbivore is inadequate in proportion to its total number, notwithstanding that Pakistan is world's third or fourth largest milk producer. Undefended cattle farmers are further cutting production by shortening bovine animals to tolerate rising input costs of electricity and fodders.
This huge size of cattle brings about millions of tons of dung daily, large part of which is unmanageable due to lack of alternative arrangements, thereby going wasted untreated. Besides posing danger to ecology, this is tantamount to irreparable economic loss. In some scattered cattle farms nationwide, biogas plants are installed and functioning to cater insufficiently to the demands of gas of famers. A separate plant is needed to make gas produce electricity, and which is why perhaps this additional utilization is not widespread.
According to a rough estimate, in Karachi there are over 800,000 cattle in various urban cattle settlements that daily send out over 6000 tons dung in the sea without treatment, endangering marine lives, causing methane emissions to debilitate growth of flora and fauna on coastline, and overall creating serious environmental hazards. Several studies have been hacked out, warning ecological fallouts of the pollutants and drain of economic resources through these otherwise manageable wastes. However, no arrangement has been made so far to set up waste treatment or biogas plants to make use of non-edible materials coming out of main cattle farms of Landhi, Korangi, Surjani, etc. Generation of gas is more viable project in any of these cattle farms. Especially in Landhi cattle farm, generally known as Behns Colony, that houses highest heads of bovine of around 400,000 citywide, biogas project can not only be feasible economically, environmentally, and geographically, but it is also needed to meet the enormous energy needs of 2,000 cattle farms, at least.
With this large numbers, Landhi cattle colony is recognized internationally for having considerably immense urban dairy farming. Government realized the commercial viability of setting up biogas plants in the area, but failed in facilitating or establishing single biogas plant. According to Shaukat Mukhtar, Joint Secretary Karachi Dairy Farmers Association, a mega biogas plant would soon be established in the colony. The capacity of electricity production of this plant will be about 35MW and it would churn out 1500 tons of organic fertilizers daily, he told this scribe. His own cattle farm has a running biogas plant, "which comprising cubic shaped fermentation tank and cylindrical gas holder is introduced with slurry (dung plus water) in the inlet of tank where fermentation occurs to generate gas that is through pipes transferred to the gas holder", he briefed through demonstration. The quality of food cooked on this gas certainly does not change, he said while pointing towards a pot heated on the oven combusted with biogas in a corner of his cattle farm, located at the extension phase of Behns Colony.
He said the capacity of the plant was 80 cubic feet. "We are also utilizing the gas to run an electricity generator." He has a 10 KV generator in the farm, which he says is sufficient to electrify whole farm during load shedding. Gas outage could not bother us, he replied to a question. It is a pilot biogas plant, installed one year back free of cost by a British company, he said. "The plant needs space, electricity, and a lot of water, all that we are providing." Fermentation process requires substantial quantity of water. Different news reports have been highlighting the issue of shortage of water in Behns Colony. Normally 50-kilogram organic fertilizer, having good quantity of nitrogen, is recovered from 10 tons dung, says Shaukat.
Not only livestock sector leads to economically valuable by-products, it also is a large consumer of wastes of agriculture industry. For example, a significant quantity of molasses, wheat straw, cotton seed cake, and rice polish is consumed by herbivore in farms. However, rising prices of fodders are compelling cattle farmers to attrite farming. Low productive animals are increasing their burdens; therefore, they are either selling or culling them to cut short overheads. Needless to say, there is an urgent need to expedite researches on genetics to spawn high productive breeds. In addition, sense of managing available resources and turning a challenge in to opportunity is required to generate biogas from low productive, large in numbers cattle.