Cement, Energy and Environment

- Biofuel UNIVERSITY OF NEVADA DEVELOPS BIOFUEL FRO SEWAGE SLUDGE A team of researchers from the University of Nevada at Reno, US, is out to prove that sludge from a wastewater treatment plant can be dried, powdered , gasified as biofuel , and then burned to generate electricity, which in turn can run equipment at the same treatment plant. Sewage sludge, as its name implies, is a liquid, and normally it would take an enormous amount of energy - or a lot of space and time - to dry it into powder form. To accomplish the task economically, the team of researchers built a processing machine based on a bed of sand and salts, which can be operated at a relatively low temperature. Waste heat from the process is also reclaimed to generate electricity. It should also be noted that processing sludge on site also saves a great deal of energy, compared to trucking it off site for disposal, which would help make the cost of running the system more competitive. Courtesy: TERI (The Energy and Resources Institute), 16-30 September 2010, P24. BIOMASS, BIOFUEL, AND FOOD SECURITY Dr. RS Prasad (Senior Scientist), DR HC Joshi(Principal Scientist), and MS Dhanya (Research Scholar, PhD), with the Division of Environmental Sciences, Indian Agricultural Research Institute, New Delhi-11 0012. Food and energy security are at the forefront of environmental issues, engaging the attention of all countries . And climate changes poses fundamental threats to Asia's food and energy security, which is left unchecked, will result in an upsurge of migration into the already overburndened mega cities. Biofuels have come into prominence as they are considered to be an environment-friendly energy source with the potential for reduced gas emissions. Energy inputs into biomass production, transportation, and conversion are assumed to be biomass based, resulting in a C0 2 -neutral (carbon dioxide-neutral) fuel cycle. The C0 2 released in biomass combustion is assumed to be balanced by the C0 2 removed from the atmosphere when the biomass was grown. Biofuels are a viable option for achieving the targeted gas emission reduction by many countries. But, any attempt to divert land for biofuel is not a viable option, as the demand for food is rising rapidly. More alarming is the forecast that food prices will increase by 20% - 40% in the next decade. Cellulosic biomass resources are abundant and have multiple application potential and can be converted to ethanol by hydrolysis and subsequent fermentation. In India, the total crop residue including fodder and non-fodder production during 1996/97 was estimated to be 626 Mt (million tonnes) of air-dry weight. The dominant residues are those of rice , wheat, sugarcane, and cotton, accounting for 66 per cent of the total residue production. Crop residues, which are used as fodder, will not be available as feedstock for energy. The total potential of non-fooder crop residues available for energy is estimated to be 325 Mt and 450 Mt for 1996/97 and 2010, respectively. Besides this, a portion of the agri-residues (rice, wheat straw, corn stover, stalks, leaves, and branches), which are presently burnt or left in the field due to mechanized farming (especially in Punjab, Haryana, and other parts of the country) may, therefore , be utilized for biofuel production. Ethanol production technologies for sugar (cane, beet molasses, and in small quantity sweet sorghum) and starch crops (grains) are well– developed, but have certain limitations. Oil from Jatropha curcas seeds is used for making biodiesel fuel in Philippines and Brazil , where it grows naturally. Likewise, Jatropha oil is being promoted as an easily grown biofuel crop in hundreds of projects throughout India and other developing countries. However, Jatropha suffers from certain limiting factors such as the availability of high yielding Jatropha saplings to the grower, low yield on marginal land, and land availability. But the real challenge lies in the efficiency and cost effectiveness of the technology that requires focussed R&D (research and development) and governmental policies. Introduction The total world consumption of energy equivalent is about 10 billion tonnes of crude oil, of which 80 per cent comes from fossil fuels . The commercial energy consumption in the developed world has increased during the last three to four decades and is more than 80% of the total world consumption. And 20% of the energy is consumed by 70 per cent of the world population in developing and social countries. India ranks sixth in the world in terms of energy demand with total energy consumption of around 484.40 Mt, of which 53 per cent is from fossil fuels. But India produces only about 25 per cent of the total energy requirement. The 73