Glass recycling – An effective way to save energy and environment:
Generally, beer, wine bottles and other food jars etc., are among the few normal household glass items put into landfills every day. The glass in these items can take up space in the landfills for up to 4000 years.
A. The beauty of glass is, it is one of the few materials that can be recycled indefinitely, yet only about 22 percent of the glass produced today is from recycled materials. Glass is generally produced from sand, lime and soda and uses about 40 percent more power to produce from raw materials than it does with recycled materials.
B. It may be noted, “For every ton of glass that is recycled to make new glass products 693 pounds of carbon dioxide is saved”.
C. However, not all the glass items are recyclable. The glass in light bulbs, cook ware and window panes are not recyclable due to some special additives used to the glass. These additives are ceramics and other impurities that generally contaminate the recycling process. The glass that cannot be recycled only plays a small part of the glass that is put into the landfills though.
D. The process of glass recycling is less extensive than the process of making it from raw materials. Once glass is picked up and taken to the recycle center it is separated by color and then broken into small pieces. The broken glass pieces are then crushed and sorted before being cleaned and added to raw materials to make the final glass product. Crushed glass melts at a lower temperature than the raw materials and therefore the more recycled material that is in the mixture the less energy it takes to melt the materials into glass.
E. Producing glass from all raw materials creates nearly 400 pounds of mining waste and by replacing 50 percent of the raw material with recycled glass about 75 percent of that waste is reduced.
F. Reusing glass is another way to recycle - Even better than glass recycling is actually reusing the glass containers, as this uses no energy at all! Whilst returning bottles in exchange for a refundable deposit was at one time commonplace, nowadays milk bottles are one of the few types of glass bottle which are returned for reuse. You can, however, reuse glass bottles and jars yourself, perhaps for homemade jam etc.
G. The benefits of glass recycling are crystal clear - Because glass containers are almost always recycled into other glass containers. Metals or plastics, on the other hand, often become entirely different products. A recycled glass container is just as strong as one made from virgin material, and it can be recycled again and again without any loss of quality. This makes glass recycling one of the best examples of “closing the loop.”
H.Advantages of glass recycling are given in the following points–
(a) Recycling reduces the demand for raw materials. There is no shortage of the materials used, but they do have to be quarried from our landscape, so from this point of view, there are environmental advantages to recovering and recycling glass. For every tonne of recycled glass used, 1.2 tonnes of raw materials are preserved.
(b) The cost savings of recycling is in the use of energy. Compared to making glass from raw materials for the first time, cullet melts at a lower temperature. So we can save on energy needed to melt the glass.
(c) Glass produced from recycled glass reduces related air pollution by 20% and related water pollution by 50%.
(d) Recycling glass reduces the space in landfills that would otherwise be taken up by used bottles and jars.
(e) Using glass for recycling means there are less glass objects lying around in he landfill or bin.
Desert Solar Power – Future of environmentally clean and sustainable Energy:
A recent renewed interest in alternative energy technologies has revitalized interest in solar thermal technology, a type of solar power that uses the sun’s heat rather than its light to produce electricity. Although the technology for solar thermal has existed for more than two decades, projects have languished while fossil fuels remained cheap. But solar thermal’s time may now have come — and mirrored arrays of solar thermal power plants, hopefully, will soon bloom in many of the world’s deserts.
Large desert-based power plants concentrate the sun’s energy to produce high-temperature heat for industrial processes or to convert the solar energy into electricity. It is quite interesting to note that, as per the recent reports on Solar Power, the resource calculations show that just seven states in the U.S. Southwest can provide more than 7 million MW of solar generating capacity, i.e., roughly 10 times that of total electricity generating capacity of U.S. today from all sources.
In US, as per report, four more concentrating solar technologies are being developed. Till now, parabolic trough technology (i.e., tracking the sun with rows of mirrors that heat a fluid, which then produces steam to drive a turbine) used to provide the best performance at a minimum cost. With this technology, as per the report, since the mid-1980s nine plants, totaling about 354 MW, were operating reliably in California’s Mojave Desert. Natural gas and other fuels provide supplementary heating when the sun is inadequate, allowing solar power plants to generate electricity whenever it is needed. In addition, in order to extend the operating times of solar power plants new heat-storing technologies are being developed as well.
Realizing the advantages of solar energy and seeing the success of desert solar power installed, several solar power plants are now being planned in the U.S. Southwest. Renewed Governmental supports and rising fossil fuel prices including natural gas, lead to new interest in concentrating solar power among many entrepreneurs. Efficiency of concentrating solar technologies has also been improved substantially, since then. While earlier trough plants needed a 25 percent natural gas-fired backup, the new improved plants will require only about 2 percent backup. As per recent news in US, utilities in states with large solar resources such as Arizona, California, Nevada, and NewMexico etc., are considering installation of solar dish systems on a larger scale. As per the latest estimation, within the next decade more than 4,000 MW of central solar plants will be installed. It’s quite encouraging!!
Concentrating Solar Technologies -
(a) Parabolic trough technologies track the sun with rows of mirrors that heat a fluid. The fluid then produces steam to drive a turbine.
(b) Central receiver (tower) systems use large mirrors to direct the sun to a central tower, where fluid is heated to produce steam that drives a turbine. Parabolic trough and tower systems can provide large-scale, bulk power with heat storage (in the form of molten salt, or in hybrid systems that derive a small share of their power from natural gas).
(c) Dish systems consist of a reflecting parabolic dish mirror system that concentrates sunlight onto a small area, where a receiver is heated and drives a small thermal engine.
(d) Concentrating photovoltaic systems (CPV) use moving lenses or mirrors to track the sun and focus its light on high-efficiency silicon or multi-junction solar cells; they are potentially a lower-cost approach to utility-scale PV power. Dish and CPV systems are well suited for decentralized generation that is located close to the site of demand, or can be installed in large groups for central station power.
Conclusion – Now also the cost of solar power is quite high. In fact, for solar energy to achieve its potential, plant construction costs will have to be further reduced via technology improvements, economies of scale, and streamlined assembly techniques. Development of economic storage technologies can also lower costs significantly. According to renewable energy department, a solar plant covering 10 square miles of desert has potential to produce as much power as the Hoover Dam of US produces. Thus, desert-based power plants can provide a large share of the nation’s commercial energy needs.
Solar power – Energy that is most sustainable to protect our economy and environment:
Originally developed for energy requirement for orbiting earth satellite - Solar Power – have expanded in recent years for our domestic and industrial needs. Solar power is produced by collecting sunlight and converting it into electricity. This is done by using solar panels, which are large flat panels made up of many individual solar cells. It is most often used in remote locations, although it is becoming more popular in urban areas as well.
There is, indeed, enormous amount of advantages lies with use of solar power specially, in the context of environmental impact and self-reliance. However, a few disadvantages such as its initial cost and the effects of weather conditions, make us hesitant to proceed with full vigor. We discuss below the advantages and disadvantages of Solar Power:
Advantages -
(a) The major advantage of solar power is that no pollution is created in the process of generating electricity. Environmentally it the most Clean and Green energy. Solar Energy is clean, renewable (unlike gas, oil and coal) and sustainable, helping to protect our environment.
(b) Solar energy does not require any fuel.
(c) It does not pollute our air by releasing carbon dioxide, nitrogen oxide, sulfur dioxide or mercury into the atmosphere like many traditional forms of electrical generation does.
(d) Therefore Solar Energy does not contribute to global warming, acid rain or smog. It actively contributes to the decrease of harmful green house gas emissions.
(e) There is no on-going cost for the power it generates – as solar radiation is free everywhere. Once installed, there are no recurring costs.
(f) It can be flexibly applied to a variety of stationary or portable applications. Unlike most forms of electrical generation, the panels can be made small enough to fit pocket-size electronic devices, or sufficiently large to charge an automobile battery or supply electricity to entire buildings.
(g) It offers much more self-reliance than depending upon a power utility for all electricity.
(h) It is quite economical in long run. After the initial investment has been recovered, the energy from the sun is practically free. Solar Energy systems are virtually maintenance free and will last for decades.
(i) It's not affected by the supply and demand of fuel and is therefore not subjected to the ever-increasing price of fossil fuel.
(j) By not using any fuel, Solar Energy does not contribute to the cost and problems of the recovery and transportation of fuel or the storage of radioactive waste.
(k) It's generated where it is needed. Therefore, large scale transmission cost is minimized.
(l) Solar Energy can be utilized to offset utility-supplied energy consumption. It does not only reduce your electricity bill, but will also continue to supply your home/ business with electricity in the event of a power outage.
(m) A Solar Energy system can operate entirely independently, not requiring a connection to a power or gas grid at all. Systems can therefore be installed in remote locations, making it more practical and cost-effective than the supply of utility electricity to a new site.
(n) The use of solar energy indirectly reduces health costs.
(o) They operate silently, have no moving parts, do not release offensive smells and do not require you to add any fuel.
(p) More solar panels can easily be added in the future when your family's needs grow.
(q) Solar Energy supports local job and wealth creation, fuelling local economies.
Disadvantages –
(a) The initial cost is the main disadvantage of installing a solar energy system, largely because of the high cost of the semi-conducting materials used in building solar panels.
(b) The cost of solar energy is also high compared to non-renewable utility-supplied electricity. As energy shortages are becoming more common, solar energy is becoming more price-competitive.
(c) Solar panels require quite a large area for installation to achieve a good level of efficiency.
(d) The efficiency of the system also relies on the location of the sun, although this problem can be overcome with the installation of certain components.
(e) The production of solar energy is influenced by the presence of clouds or pollution in the air. Similarly, no solar energy will be produced during nighttime although a battery backup system and/or net metering will solve this problem.
(f) As far as solar powered cars go - their slower speed might not appeal to everyone caught up in today's fast track movement.
Conclusion - Solar power technology is improving consistently over time, as people begin to understand the benefits offered by this incredible technology. As our oil reserves decline, it is important for us to turn to alternative sources for energy. Therefore, it would be better that converting some of the world's energy requirements to solar power are in the best interest of the worldwide economy and the environment. Since we all are aware of the power of the sun and the benefits we could get from it.
Bio-degradable plastics – development and use are the key for improvement of environment:
A. At present, we make almost 100% of plastics of our requirement from oil and natural gas. Petroleum-based plastics are basically non-degradable. As concern grow about the potential bad effects of petroleum-based non-degradable plastics on the environment, the viability of petroleum-based plastics are in question. At the same time, the increased dependence on oil and gas imports due to manufacture of such petroleum-based products, make us think about the possible solution. In this respect, searching for suitable degradable polymers for various applications as per the need, have become very important aspect in today’s science and technological affair for research.
B. As per reports of various environment protection agencies, plastics alone account for more than 25% (by volume) of municipal waste generated. Plastic’s low density and slowness to decompose makes them a visible pollutant of public concern. Some of the techniques adopted for integrated waste management, which include recycling, source reduction of packaging materials, composting of degradable wastes, incineration etc., may help reduce waste disposal problem; but this will not solve the importation of petroleum products and problem with non-degradability of plastics. As per statistics, about 80% of post-consumer plastic waste is sent to landfill – degrading land masses and causing water pollution, 8% is incinerated – causing unwanted emission and only 7% is recycled. The situation is so acute in some countries of Europe of Japan that today few sites left that can be used for landfill. Since the main bulk of domestic waste is made up of plastics there is a great deal of interest in recycling plastics and in producing plastic materials that can be safely and easily disposed of in the environment.
C. The option to get rid of the adverse effects of non-degradable petroleum-based plastics may be to make bio-degradable plastics suitable for our various applications. Some of the manufacturers in developed countries have already developed some type of degradable plastics made from agricultural products such as corn, potato etc. In fact, bio-degradable plastics can be made from lactic acid. Lactic acid is produced (via starch fermentation) as a co-product of corn wet milling, which can be converted to polyactides (PLA). Alternatively, it can be produced using the starch from food wastes, cheese whey, fruit or grain sorghum.
D. The properties of the plastics changes as per the applications for which it is needed. Some plastics need to be durable like the parts in a car. Yet, there are many plastics that are only used once or have a limited life before being thrown into a landfill or incinerator. Plastics, unlike most organic polymers, are poorly degraded by microbes (although recently some genetically engineered microbes / bacteria have been invented to transform plastic waste into useful eco-friendly plastics – but it is still in research stage). Environmentally degradable polymers are one potential solution to replacing petroleum-based polymers. Potential uses for these polymers are plastics intended for one-time or limited use, for example those used as fast-food wrappers and water-soluble polymers in detergents and cleaners, and for use in the printing industry. Thus, an ideal degradable product would:
(a) Perform the intended task effectively;
(b) Produce little or no side effects in any non-intended target;
(c) Break down, along with any residues of its activity, over a reasonably short time scale;
(d) Produce no harmful substances when it breaks down.
E. Waste disposal: The question now arises, how best to dispose of domestic wastes. The ways of disposing of waste and time required for degradation is very important factors in development of bio-degradable plastics. Current bio-degradable polymers are designed to degrade either biologically or chemically, depending on the disposal environment that they will encounter after use. Ideally, degradation pathways should ultimately lead to the bio conversion of the polymer into carbon dioxide (aerobic) or carbon dioxide/methane (anaerobic) and biomass. Environmental laws and regulations and consumer demands for environmentally friendly products are beginning to have an impact on the use of degradable polymers. As a result degradable polymers, when combined with other degradable plastics, will begin playing a crucial role in helping to solve our waste disposal problems and reducing petroleum imports.
F. Properties of bio-degradable polymers: These new polymers developed from agricultural products described above are truly degradable. These polymers may be used in many applications as well. Some are impervious to water, moisture etc., and retain their integrity during normal use, but readily degrade when they are kept in a biologically rich environment. The amazing part is the full biodegradability can occur only when these materials are disposed of properly in a composting site or landfill. Today, there are three major degradable polymers groups that are either entering the market or are positioned to enter the market. They are
(a) polyactides (PLA),
(b) polyhydroxybutyrate (PHB) and
(c) starch-based polymers.
G. Design for Bio-Degradation of Polymer: Following few points are given to attain bio-degradability. (a) Some organic chemicals degrade only very slowly, and so the level in the environment can rise steadily. These are the persistent organic pollutants (or "POPs").
(b) In contrast, all chemicals produced in nature are 100% degradable and understanding why this is the case is an important part of being able to design synthetic degradable materials.
(c) For example, natural polymers such as carbohydrates, proteins and nucleic acids usually have oxygen or nitrogen atoms in the polymer backbone. If these atoms are included in synthetic polymers, the material is more easily degraded. A carbon-oxygen double bond (carbonyl group) absorbs light energy, and so can make a substance photodegradable.
(d) These features can be seen in the structures of some degradable polymers that are already in use.
H. Bio-degradable polymers are quite new. Only during last five years some bio-degradable polymers for applications have been in use in some of the developed world. Although they are degradable, the industry has not promoted them. One reason is these new polymers are higher priced than the commodity polymers typically in use in plastics applications. However, producers are currently working toward bringing down the price of degradable polymers by increasing production capacity and improving process technology.
I. Price competitiveness and future growth of bio-degradable polymers: The trend observed regarding bringing down the prices of degradable polymers in last five years is quite encouraging. In US, five years ago PLA and PHB sold for more than USD 25.00 per pound. Today PLA, depending on quantities, is between USD 1.50 and USD 3.00 per pound and PHB, in large quantities is near USD 4.00 per pound.
Though recent advances in production technology have helped lower prices of some degradable resins, prices are still higher than for petroleum-based plastics. This suggests that in the short term, companies making degradable polymers will continue to focus on niche markets. As production capacity increases it is expected that future prices to fall to roughly USD 1 per pound. Moreover, due to sharp increase in prices of petroleum-based plastics in recent time, the prices of bio-degradable polymers will become very much competitive soon.
J. Further, several factors, besides cost, will be important in determining the future growth of degradable polymers. One major obstacle is a lack of a composting infrastructure. Large-scale composting would provide the ideal disposable environment for spent degradable. Future legislation will depend not only on the environmental awareness of planners and politicians but also on their perceptions of how degradable polymers may affect the development of plastics recycling.
R&D priorities in biotechnology are essential to take care of post-Kyoto challenges:
A. Global Warming: The third session of the Conference of the Parties to the United Nations Framework Convention on Climate change, held in Kyoto, Japan, on December 1997, agreed on a protocol which includes each party’s quantitative commitment to reduce its emissions of greenhouse gases, such as carbon dioxide (CO2) by 2010. The protocol specifies that the European Union will commit itself to reducing its greenhouse gas emissions by 8 per cent by 2010 from the level of 1990 (base year), the United States by 7 per cent, and Japan and Canada by 6 per cent. As an essential element in achieving this goal, industry must reduce energy consumption in order to maintain development while helping to meet these targets.
This would include a shift from present petrochemical industry processes, which consume large quantities of energy under conditions of high temperature and pressure, to more energy-efficient biological processes, which use renewable resources such as biomass to produce useful substances under normal temperatures and pressures. For example, future processes will focus more on producing efficiently alternative fuels such as ethanol, which contribute less to global warming and are also likely to produce environmentally benign products, such as biodegradable plastics, which breaks down in natural settings after use.
As a result, biotechnology should become an increasingly valuable tool for developing environmentally friendly products and processes and for preventing the Earth from warming.
B. R&D priorities in biotechnology for promotion of clean industrial products and processes: If biotechnology is to become an increasingly important source of clean industrial products and processes, R&D efforts will need to focus on a number of priority areas. Among those that deserve prompt and focused research in the near future are:
a. Innovative products derived from biological sources that contribute to sustainability;
b. Wider exploration of biological systems (enzymes, micro-organisms, cells, whole organisms);
c. Greater emphasis on the use of bioconsortia, including establishing them and developing production and degradation processes based on them;
d. Novel methodologies for developing biological processes (bio-molecular design, genomics);
e. Innovative biocatalyst technology for use in areas where conventional biocatalysts have not yet been exploited (e.g. the petrochemical industries);
f. Biological recycling processes that convert unused resources to useful substances;
g. Emphasis on engineering, especially large-scale engineering, process intensification, measurement, monitoring and control systems;
h. Greater emphasis on biodiversity and widening the search for novel genes (bioprospecting), a process that will require, in parallel, the construction of infrastructures such as culture collections, comprehensive biological databases, and the development of bioinformatics;
i. Focus on development and application of recombinant technology.
Global Warming - Each one degree rise in the temperature of the world's oceans is equivalent to 1.4 BILLION one Megaton atom bombs!!!
We all know, the earth is surrounded by a cover of gasses as atmosphere. This atmosphere allows most of the light to pass through, which reaches the surface of earth.
This light from sun is absorbed by the earth surface and converts into heat energy. This heat energy is re-emitted by the surface of the earth during night.
Due excessive presence of some gasses in the atmosphere, this escape of heat from earth surface is prevented, resulting in heating of earth called ‘global warming’.
The gasses which are responsible for causing global warming are called ‘greenhouse gasses’. Carbon dioxide is one of the most important greenhouse gases. This carbon dioxide mostly comes to atmosphere as air pollution from vehicles, coal-fired power plants and other industries burning fossil fuels. Human population increase and large scale deforestation are also responsible for carbon dioxide generation.
Thus, Global Warming adds energy to the Earth's biosphere.
The climate change which we are experiencing is due to global warming.
Heat is the fuel of weather systems. More heat, more extreme weather.
Energy drives the water cycle.
The more energy there is the faster the water cycle is driven and the more extreme the weather patterns become.
Each one degree rise in the temperature of the world's oceans is the equivalent to 1.4 BILLION one Megaton atom bombs; that is a lot of energy! This tremendous amount of devastating energy, generating because of our faulty creation “Global Warming” is responsible for the present climate change.
Thus, it shouldn't be surprising that the result is more extreme weather. More rain, more drought and more storms.
The harmful effects of presence of greenhouse gasses in atmosphere are global warming, climate change, ozone depletion, sea level rise, adverse effects on biodiversity etc.
Therefore, our prime responsibility is not to promote any industrialization which enhances carbon emission, rather than reduction.
Proper energy mix, which generates electricity without emission, is essential. Energy mix should include –
(a) substantial enhancement of Nuclear power in the industrialized countries;
(b) only clean coal technology / green coal to be used for power generation;
(c) wherever possible tap hydro-power;
(d) substantial effort needed to enhance research and implementation for provision of generation of clean energy from renewable sources such as solar and wind.
Biotechnology and industrial sustainability in producing clean industrial products:
A. Introduction: Various points have been given below regarding role of biotechnology and industrial sustainability in producing clean industrial products:
a. Industrial sustainability demands a global vision and co-ordinated policy approaches. b. In an industrial context, sustainability is equated with clean industrial products and processes. c. Biotechnology is competitive with and in many cases complements chemical methods for achieving clean technologies. d. It is essential to determine what is clean or cleaner, using Life Cycle Assessment and related methods. e. Biotechnology is a versatile enabling technology that provides powerful routes to clean industrial products and processes and is expected to play a growing role.
B. Biotechnology and CO2 emissions: Fossil carbon represents the single most important raw material for energy generation and for chemicals manufacture, but its oxidation product, CO2, is an important greenhouse gas. Any means of reducing fossil carbon consumption, either by improving energy efficiency or by substituting alternative resources will directly result in lowered CO2 production and thus reduce global warming.
C. Industrial processes: Use of biotechnology has already resulted in energy reduction in industrial processes. In only a few instances can the reductions be quantified, and these are presented in this report. Others are only available as anecdotal evidence. As yet, there are insufficient data to allow scaling up these figures to cover whole industrial sectors.
Examples: a. Ammonium acrylate, a key intermediate in the manufacture of acrylic polymers, is made by hydrolyzing acrylonitrile to acrylic acid and reacting this with ammonia. The reaction is energy-intensive and gives rise to by-products which are difficult to remove. A process, based on a bacterial enzyme which directly synthesises ammonium acrylate of the same quality under less energy-demanding conditions, has been operating for several years at full scale.
b. In paper making, treating cellulose fibres in the pulp using cellulase and hemicellulase enzymes allows water to drain more quickly from the wet pulp, thereby reducing processing time and energy used for drying. Trials have shown that machine speeds can be increased by up to 7 per cent and energy input reduced by as much as 7.5 per cent. Replacing thermomechanical pulping by biopulping has resulted in up to 30 per cent reduction in electrical energy consumption.
D. Materials: Biomass, as it grows, consumes CO2. Substances made from such renewable raw materials are therefore a zero net contributor to atmospheric greenhouse gases, unless fossil fuel is used in their manufacture. A wide range of chemicals and structural materials can be based on biological raw materials including biodegradable plastics, biopolymers and biopesticides, novel fibres and timbers. Plant-derived amides, esters and acetates are currently being used as plasticisers, blocking/slip agents and mould-release agents for synthetic polymers. Uses of biohydrocarbons linked to amines, alcohols, phosphates and sulphur ligands include fabric softeners, corrosion inhibitors, ink carriers, solvents, hair conditioners, and perfumes.
E. Chemicals from biological feedstocks: It is no longer necessary to start with a barrel of oil to produce chemicals. Corn, beets, rice – even potatoes – make excellent feedstocks. The fact that micro-organisms transform sugars into alcohol has been known for a very long time. But only since the advent of genetic engineering is it feasible to think about harnessing the sophistication of biological systems to create molecules that are difficult to synthesise by traditional chemical methods.
For example, the polymer polytrimethylene terephthalate (3GT) has enhanced properties compared to traditional polyester (2GT). Yet commercialization has been slow to come because of the high cost of making trimethylene glycol (3G), one of 3GT’s monomers. The secret to producing 3G can be found in the cellular machinery of certain unrelated microorganisms. Some naturally occurring yeasts convert sugar to glycerol, while a few bacteria can change glycerol to 3G. The problem is that no single natural organism has been able to do both. Through recombinant DNA technology, an alliance of scientists from DuPont and Genencor International has created a single micro-organism with all the enzymes required to turn sugar into 3G. This breakthrough is opening the door to low-cost, environmentally sound, large-scale production of 3G. The eventual cost of 3G by this process is expected to approach that of ethylene glycol (2G). The 3G fermentation process requires no heavy metals, petroleum or toxic chemicals. In fact, the primary material comes from agriculture – glucose from cornstarch. Rather than releasing carbon dioxide to the atmosphere, the process actually captures it because corn absorbs CO2 as it grows. All liquid effluent is easily and harmlessly biodegradable. Moreover, 3GT can readily undergo methanolysis, a process that reduces polyesters to their original monomers. Post-consumer polyesters can thus be repolymerised and recycled indefinitely.
F. Clean fuels: While biomass can be consumed (incinerated) directly to produce energy, it can also be converted into a wide range of chemicals and liquid fuels. Although, in energy terms, annual land production of biomass is some five times global energy consumption, biomass presently provides only 1 per cent of commercial energy. Biomass energy cannot compete at present-day prices with fossil fuels and has so far penetrated the market only where governments have effectively subsidised its use. Bioethanol is a CO2-neutral alternative liquid transportation fuel. As new technologies – including continuous fermentation, production from lignocellulosic (wood and agricultural crop) waste – and more efficient separation techniques are developed, the cost of bioethanol will compete with that of gasoline. Over a 20-year period, US ethanol production, based solely on lignocellulosic waste, could rise to 470 million tonnes a year, equal to present gasoline consumption in energy terms.
Characteristics of Pollutants from Car Exhaust and suggested solution:
The internal combustion engine is an engine in which the combustion of fuel and an oxidizer (typically air) occurs, and generates gases at high temperature and pressure, which are permitted to expand to perform useful work. Internal combustion engines are most commonly used in automobiles such as trucks, cars, motorcycles etc.;in a wide variety of aircraft and locomotives; running of various equipments, and they appear mostly in the form of turbines where a very high power is required, such as in jet aircraft, helicopters, and large ships.
Motor fuel, by which almost all internal combustion engine runs, is obtained from crude oil. Its major constituents are the elements carbon (C), hydrogen (H), oxygen (O) and nitrogen (N), along with some amounts of sulfur (S). In other words, motor fuel contains hydrocarbons and organic compounds containing nitrogen and sulfur. When these are burned in air the products are water (H2O), carbon dioxide (CO2), carbon monoxide (CO) and oxides of nitrogen (NOx). Nitrogen gas in the atmosphere may also react with oxygen at the high temperatures in the combustion chamber to form oxides.
Characteristics of Pollutants from Car Exhaust:
a. Carbon dioxide (CO2) - This gas is naturally present in the atmosphere at low concentration (approximately 0.035%). It absorbs infrared energy and is thus a greenhouse gas, a contributor to global warming. Concentrations of CO2 in the earth's atmosphere appear to be increasing. This is a great concern as it has a substantial effect on the climate. The internal combustion engine contributes to the increased concentrations of CO2 in the atmosphere.
b. Carbon monoxide (CO) - The main source of CO in cities is the internal combustion engine, where it is produced by incomplete combustion. Anthropogenic sources account for approximately 6% of the 0.1 ppm concentration of CO in the earth's atmosphere globally. In an urban area, the concentration can be much higher. CO is highly toxic. It binds to haemoglobin more strongly than oxygen does, thus reducing the capacity of the haemoglobin to carry oxygen to the cells of the body. CO also has the nasty habit of sticking to haemoglobin and not coming off. This means that a fairly small amount of it can do a lot of damage. However, CO can be oxidized to the far less harmful CO2, if there is enough O2 available. At higher air-fuel ratios the level of CO emission goes down. CO can also be oxidized to CO2 in a catalytic converter.
c. Oxides of nitrogen (NOx) - While some nitrogen may be present in the fuel, most oxides of nitrogen are produced when elemental nitrogen (N2) in the air is broken down and oxidized at high temperatures (approximately at 700 degree Celsius or greater) and pressures within the internal combustion engine. Nitrogen monoxide (NO) is produced in higher concentration than nitrogen dioxide (NO2) but the two species are in any case inter-convertible by means of photochemical interactions. Other oxides of nitrogen, such as N2O4, may occur; but chances are rare. NO and NO2 are toxic species. Oxides of nitrogen also play a major role in the formation of photochemical smog.
d. Hydrocarbons (HC) - Hydrocarbon fuel, sometime, passes through the process unconsumed and is expelled into the atmosphere along with other exhaust fumes. Fuel close to the wall of the combustion chamber may be quenched by the relative coolness of that area and not be burned. Also, if the engine is poorly designed or is not in proper working order the proportion of unburned fuel rises. Some hydrocarbon fuels are also released to the atmosphere by direct evaporation from fuel tanks. It may be noted; hydrocarbons can be dangerous to human health and are also part of the makeup and cause of photochemical smog.
e. Benzene and its derivatives (C6H6) - Benzene is, of course, a hydrocarbon, but is sufficiently different from straight-chain hydrocarbons. The six carbons (C) in benzene form a regular hexagon, with one hydrogen (H) attached to each carbon and sticking out. All 12 atoms lie on one plane. This structure of benzene is quite stable — stable enough for a large proportion of the benzene in fuel to pass unchanged through the combustion process. There is quite a lot of benzene in fuel. It acts as an anti-knock agent, making cars run more smoothly. Since the abolition of lead additives as anti-knock agents, the levels of benzene and benzene-related compounds (modified form where one or more hydrogen have been removed to form a phenyl ring and other things have been attached in their places) in car fuel have increased. Benzene (C6H6), and also many of its derivatives such as toluene (PhCH3) and phenol (PhOH), is carcinogenic (the level of toxicity varies). Benzene vapors are therefore quite dangerous. It has been suggested that benzene is more dangerous to filling station attendants than to the general public in the streets as the concentration of benzene will be higher in the raw fuel than in the combustion products.
f. Sulfur dioxide (SO2) - Fossil fuels are derived from once-living organisms. Some sulfur occurs in protein and will still be present in the fuel. Under combustion this sulfur reacts with oxygen to form sulfur di- and trioxide. Sulfur dioxide emission does occur from cars. SO2 and SO3 are acidic pollutants which dissolve in moisture in the atmosphere to form sulfurous and sulfuric acids (H2SO3 and H2SO4), which are components of 'acid rain'. These corrode metal surfaces and weather limestone buildings.
Acid rain also mobilizes toxic aluminum ions in the soil, washing them out into streams and ponds. This causes sticky mucus to accumulate in the gills of fish and eventually kills them. Trees and other plants which absorb aluminum ions will be damaged. In humans, sulfur dioxide irritates the eyes, the mucous membranes and the respiratory tract, along with the skin in general. SO2 also has the effect of slowing down the movements of the cilia (the hairs in the trachea which act to prevent dust entering into lungs), thus exacerbating the irritation caused by allowing more pollutant to access the respiratory system.
g. Particles micro-particulate, 10 microns (Particulate matters – PM10) - These are ultra-fine particles which are less than one-hundredth of a millimeter across. Thus they are too small to settle or be dispersed by rain. These particles absorb acidic gases which are also present in exhaust fumes and, when inhaled, penetrate into the microscopic air sacs of the lungs (alveoli). Scavenging white blood cells are overwhelmed by these particles, and release a stream of chemicals that trigger an inflammatory reaction in the lungs, and increase the stickiness of red blood cells, thus increasing the likelihood of blood clots. The main victims of this type of pollution are the elderly, smokers, and those suffering from chest complaints, heart conditions and asthma. It is considered that PM10s may be the most important and dangerous component of vehicle pollution. These particles can drift for miles, and accumulate inside buildings. The major source of PM10s in urban air is motor vehicles, particularly diesel engines.
h. Photochemical Smog - Reactive pollutant hydrocarbons in the presence of NOx and under certain atmospheric conditions can produce a brown haze known as photochemical smog. It is formed by photochemical reactions (that is, reactions catalyzed by light) between NOx and hydrocarbons (HC). Photochemical smog is most common on windless sunny days when the ingredients are not dispersed and there is plenty of light energy available to power the reaction. Photochemical smog is characterized by the presence of particulate matter (which creates a sort of haze), oxidants such as ozone, and noxious organic species such as aldehydes.
Suggested Solutions to the vehicle exhaust problems:
(i) Catalytic Converters - Most modern cars contain catalytic converters. In these, exhaust fumes and added air pass over a catalyst where they are broken down to less harmful products.
(ii) Drive less.
(iii) Use cleaner engines – Use cars that are designed to be more fuel-efficient and less pollutant.
(iv) Drive hybrid vehicles - Whether a hybrid engine is more environmentally sound than a normal engine depends on how the car is used. For city stop-start driving, they're usually better.
(v) Keep your car in good working order
(vi) Use smaller cars.
(vii) Drive intelligently - The way a car is driven can have a huge effect on its fuel-consumption and hence on its effect on the environment.
Biotechnology for development of sustainable clean technology - Strategies:
Many developed countries started using biotechnology as a means of achieving clean or cleaner industrial products and processes. It compares biotechnological processes with competing means of securing similar goals.
Meaning of Clean technology - All stages of the life cycle of a product or process may adversely affect the environment by using up limited resources of materials and energy or by creating waste. Any substitution or change that reduces consumption of materials and energy and production of waste – including, for example, recycling of materials and energy – may be regarded as more environmentally friendly or ‘‘clean’’. Clean technology may also be equated with reduced risk.
Life Cycle Assessment is one way of comparing the relative cleanliness of a product or process.
Cleaner processes and products mean processes and products that consume less energy and material resources, generate less pollution or waste, or use renewable resources rather than petroleum or coal-based feedstock as feed. There are many reasons why an operator would switch to a cleaner process or product. Some of the more important factors most often mentioned are:
(a) Availability of raw materials;
(b) Cost factors;
(c) Market demands;
(d) Safety and health considerations;
(e) Environmental considerations;
(f) Product liability;
(g) Public image.
Thus, it is the duty of developed countries to appreciate the potential role of biotechnology in clean industrial processes and sets the stage for viewing clean processes in the context of industrial sustainability. The extents to which biotechnological thinking and practices are being introduced into industrial sectors, which have serious environmental impacts, are to be enhanced. The economic competitiveness of biotechnology for clean products and processes in these sectors are the major concerns, which Government / authorities required to be take a note and policy implementation should be in tune with sustainable development.
Scientific and technological innovations across the range of biotechnologies and the opportunities for their adoption, as well as R&D priorities are to be spelt out.
The following few points are to be kept in mind while framing strategies for promotion of biotechnology for development of clean technology, in the context of industrial sustainability:
(a) Global environmental concerns will drive increased emphasis on clean industrial products and processes.
(b) Biotechnology is a powerful enabling technology for achieving clean industrial products and processes that can provide a basis for industrial sustainability.
(c) Measuring the cleanliness of an industrial product or process is essential but complex; Life Cycle Assessment (LCA) is the best current tool for making this determination.
(d) The main drivers for industrial biotechnological processes are economic (market forces), government policy, and science and technology.
(e) Achieving greater penetration of biotechnology for clean environmental purposes will require joint R&D efforts by government and industry.
(f) For biotechnology to reach its full potential as a basis for clean industrial products and processes, beyond its current applications, additional R&D efforts will be needed.
(g) Because biotechnology, including recombinant DNA technology and its applications, has become increasingly important as a tool for creating value-added products and for developing biocatalysts, there is a strong need for harmonised and responsive regulations and guidelines.
(h) Market forces can provide very powerful incentives for achieving environmental cleanliness objectives.
(i) Government policies to enhance cleanliness of industrial products and processes can be the single most decisive factor in the development and industrial use of clean biotechnological processes.
(j) Communication and education will be necessary to gain penetration of biotechnology for clean products and processes into various industrial sectors.
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