30-06-2012, 11:24 AM
GREEN IT
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ABSTRACT
With the exploding human population on Earth, the pressure on the natural resources is high. Hence there is a need to conserve the natural resources. Therefore, harnessing energy and production of non-toxic substances such that it poses less environmental hazards has become a priority. Green Technology encompasses methods and techniques that either deals with global warming by the reduction of greenhouse gases or with sustainable development. The objective of Green Technology is to suffice to the needs of the present and the future generations without damaging or depleting the flora fauna or the natural biodiversity. This paper provides an overview of the uses of Green Technology and how Green Technology can be used for the preservation of the natural resources.
INTRODUCTION
Green Technology or Environmental Technology or Clean Technology as also known, incorporates Remediation and Sustainable technologies. Remediation Technology helps to alleviate the damage done by the pollution and pose less environmental hazards whereas, Sustainable Technologies aim to reduce the unnecessary waste. Sustainable Development is the core of Green Technology. Sustainable Development aims to meet the human needs while preserving the environment so that these needs can be met not only in the present, but also for future generations.
The use of Green Technology has assumed a lot of significance in the last decade due to the rising energy costs and the stringent carbon reduction norms passed by some nations. Hence, many business houses and companies are advocating the use of Green Technology to reduce their carbon footprint and to minimize their waste.
For example, IT giant, Wipro as part of its Eco Eye initiative to achieve ecological sustainability has started a pilot project to harness wind energy. Such projects fetch carbon credits, which in turn fetch a good price in secondary markets. One such project is the Aero Wind generator in the company’s Electronic City campus. This can power 10 street lights fitted with its LED or CFL lamps of 18 watts each for 10 hours every day. Wipro is also using food-waste from the cafeterias in its campus to generate bio-gas, which is used for cooking. The plant converts about 1,000 kg of food waste daily into gas comparable to four to six commercial cylinders of LPG.
A recent report by the United Nations Environment Programme observes, investment in green energy ($140 billion) in 2009 was higher than that in gas and coal-based power generation ($110 billion).
Continuous rise in oil prices adds to the woes of many people in the developing world. In India, Jatropha is widely used as a biofuel. It is environment friendly and causes reduction in green house gases. As compared to petroleum diesel, biodiesel generates 45-60% less particulate matter, 68% less unburned hydrocarbons, 44-45% less Carbon monoxide.
Green Technology helps to mitigate pollution and thus helps reduce environmental hazards.
ENVIRONMENTAL TECHNOLOGIES
Recycling:
It is a way of converting the waste into a resource; it uses energy to transform a resource which has been used already into a new usable product. Recycling promotes reusing a product; thus reducing the reliance on newer products, eventually saving the resource. It thus prevents wasting a product which can be useful and having great potential applications.
Materials which can be recycled are plastic, paper, glass, metal, textiles, and electronic materials. Materials to be recycled are either brought to a collection centre or picked up from the waste. Sorting cleaning and reprocessing are further carried out.
It thus helps in saving trees, energy and money and thus has great advantages from the environmental as well as economic point of view.
Water purification:
Water purification implies removing any impurity from water like contaminants or micro organisms. The need for water purification is because of water pollution. The primary step is filtering out the insoluble impurities. Biological methods like water flocculation are employed wherein chemicals are added which help in sedimentation of the impurities. The final step involves disinfection where the water can be treated with chlorine, sodium hypochlorite, ozone, etc. to remove impurities, if any.
Sewage Treatment:
Sewage is nothing but waste water from households and industries. Treatment of sewage is necessary to ensure that the receiving water into which the effluent is ultimately discharged is not significantly polluted. Sewage treatment involves:
The removal of solids by physical screening or sedimentation; and
The removal of soluble and fine suspended organic pollutants by a biological oxidation process.
Both forms of treatment produce sludge as by-products and these have to be treated and disposed of separately in an economical and environmentally acceptable way.
Environmental remediation:
In literal sense, remediation means to provide remedies and get back the ideal conditions. In this, a site is first assessed with regards to its soil, groundwater and air. Sampling and chemical analysis is carried out. A few methods of environmental remediation are as follows:
1. Excavation:
The contaminated soil is converted into a regulated landfill. It also involves aerating the excavated material while dealing with volatile compounds.
2. SEAR
The Surfactant Enhanced Aquifer Remediation (SEAR) process involves solubility and recovery. It involves the injection of hydrocarbon mitigating agents or special surfactants into the subsurface to enhance desorption and recovery of bound up recalcitrant non aqueous phase liquid (NAPL).
In geologic formations that allow delivery of hydrocarbon mitigating agents or specialty surfactants, this approach provides a cost effective and permanent solution to sites that have been previously unsuccessful in utilizing other remedial approaches.
3. Pump and treat method:
The Pump and Treat method involves pumping out contaminated groundwater with the use of a submersible or vacuum pump, and allowing the extracted groundwater to be purified by slowly proceeding through a series of vessels that contain materials designed to adsorb the contaminants from the groundwater. Chemical reagents such as flocculants followed by sand filters may also be used to decrease the contamination of groundwater.
Stabilization/solidification is a remediation/treatment technology that relies on the reaction between a binder and soil to stop/prevent or reduce the mobility of contaminants.
• Stabilization - involves the addition of reagents to a contaminated material (e.g. soil or sludge) to produce more chemically stable constituents; and
• Solidification - involves the addition of reagents to a contaminated material to impart physical/dimensional stability to contain contaminants in a solid product and reduce access by external agents (e.g. air, rainfall).
Solid waste management:
Municipal solid waste is generally used to describe most of the non-hazardous solid waste from rural and urban areas. The wastes are classified as wet garbage (like vegetable material, eggshells, etc.) and dry garbage (like paper, plastic, glass, wood, etc.).
The ways of reducing this form of waste are:
1. Source reduction:
This can be done by using less material while making a product, designing products or packaging to reduce their quantity.
2. Recycling:
Materials extracted from waste like aluminum, paper, plastic, glass, etc. are recyclable and can be used as a resource.
3. Disposal:
It is done generally through a sanitary landfill or through incineration.
Renewable Energy Resources:
Renewable energy sources are those which never get depleted and are replenished by natural processes. Thus they can never be extinct.
Other advantages of renewable energy sources are that they are pollution-free, easier energy-producing processes, etc.
1. Sun:
Solar energy refers to harnessing sun’s heat or light as a form of energy. Active solar techniques involve capturing sun’s energy through photovoltaic cells and solar collectors which convert them into electrical energy. Passive solar energy refers to orienting a building to the Sun, selecting materials with favorable thermal mass or light dispersing properties for architecture and designing spaces with natural ventilation. Various solar appliances include solar cooker, solar heater, solar cell etc.
2. Wind:
Wind-flow is used to turn turbines to generate electricity. Wind power is proportional to its velocity. Hence turbines are usually situated in places where wind velocity is more like at higher altitudes, offshore etc.
3. Hydropower:
Electricity can also be generated from flowing water through building dams across rivers. Water from these dams is allowed to fall from great heights on turbines which rotate to produce electricity.
4. Geothermal energy:
It includes harnessing of the heat in earth’s crust to generate electricity. In some places on earth surface underground hot water, heated due to earth’s molten lava, comes to surface through openings. Now the steam is directly taken out from ground to turn turbines, or hot water coming out is boiled and converted to steam to run turbines or hot water flows through heat exchangers, boiling an organic fluid that spins the turbine.
Apart from this, various other alternative sources of energy have been developed like:
Alcohol as alternative to fossil fuels:
Ethanol is a form of renewable energy source, unlike fossil fuels. Ethanol produced from corn, sugarcane and other cheap foodstuffs can be an excellent alternative to conventional fossil fuels. Brazil, which extensively uses ethanol as fuel, shows the world the way for replacing fossil fuels with ethanol. The bagasse thus produced, while manufacturing ethanol from sugarcane, can be used to process heat and power. Ethanol is a particulate-free burning fuel source, hence causes no pollution in contrast to fossil fuels.
Other recent alternative sources include:
1.Ocean-thermal energy:
This method is about harnessing the temperature difference between the air above sea and the water on sea-surface to produce steam, which runs turbines to produce electricity.
2. Floating wind farms:
Floating wind farms refers to ordinary wind farms placed deep in oceans or seas. The advantage of these over conventional wind farms is being able to harness winds without any obstructions like trees, buildings, etc.
3.Piezo-tree:
It is an artificially developed energy-harvesting tree made up of Polyvinylidene Fluoride. Here the flapping motion of the leaves leads to instability of the aero-elastic system. This disturbance is used to convert wind energy to electrical energy.
4. Biogas digestion:
Biogas digestion deals with harnessing the methane gas that is released by breaking down of waste by micro-organisms in Bio-digesters.
5. Helioculture:
Helioculture refers to the process wherein carbon dioxide in atmosphere is made to combine in presence of sunlight to form liquid fuel. It serves the dual purpose of removing CO2 from atmosphere as well as fuel production.