Carbon trading is market based tool to limit GHG emissions – effective for management of Carbon footprint
1. Introduction –
Carbon emissions into the earth’s atmosphere have resulted in drastic climatic changes. In 1997, in Kyoto, developed Industrialised countries pledged to reduce the production of greenhouse gases which contribute to Global warming by a minimum of 5% by 2012, compared to a 1990 baseline. The Greenhouse Gases which include Carbon di-oxide (CO), Methane (CH4) and also other oxides on account of incomplete combustion substantially disturb the balance of the heat in the earth’s atmosphere leading to warming of the atmospheric temperature which is called as Global Warming and is considered a major threat to life on earth.
Carbon trading is the idea is to develop a mechanism to allow market to drive industrial and commercial processes in the direction of low emissions. Working in that direction, Governments of various countries are trying to come up with, a trading mechanism where companies gain a monetary benefit out of polluting the air less. Kyoto protocol’s goal is exactly that. The idea is to divide the whole world into two, one who can afford making changes to their existing infrastructure and the ones who cannot. As everybody is polluting, be it a developed country or a developing country, the financial aspect has to be kept in mind. All developed countries will have to cut down their emissions by some x percentage or else they pay heavy fines. Now, one way of measuring how much they are polluting the air less, is by clean each tonne reduction of CO2 a unit and a company must own those amounts of units at the end of every period.
Carbon trading, sometimes called emissions trading, is a market-based tool to limit Greenhouse gas (GHG). Emissions trading aims at efficient investments in emission reduction. In other words, carbon credits are a key component of national and international emissions trading schemes that have been implemented to mitigate global warming. They provide a way to reduce greenhouse effect emissions on an industrial scale by capping total annual emissions and letting the market assign a monetary value to any shortfall through trading. The carbon market trades emissions under cap-and-trade schemes or with credits that pay for or offset GHG reductions.
2. Mechanism of Emission Trading System and functionalities –
In its simplest form, a “cap and trade” program has two main components. An emissions trading scheme (ETS) attempts to put a price on the emissions of a targeted gas, so as
to make firms internalize environmental resources in their business decisions. A cap is set for aggregate emissions in the system. Allowances are then issued that allow their holders to emit a certain quantity of the targeted gas. The sum of all allowances issued is equal to the overall cap. Firms are then allowed to trade these allowances. If it is cheaper to reduce emissions than buy an allowance, then a firm will become a net seller; conversely, if it is cheaper for a firm to buy allowances than reduce its emissions, then it becomes a net buyer.
As mentioned above, the first component is a ceiling or “cap” established on aggregate air emissions, which typically declines over time. This declining or “phasing-in” of the cap sets a maximum limit on emissions and imposes a legal obligation that ensures the specific longer-term environmental goals are met. By phasing in the cap over multiple periods, companies regulated by the program can begin investing in compliance while reduction requirements are less aggressive, and then accelerate their strategies as the cap is ratcheted down over time. Emitters within economic sectors covered by the program are responsible for reducing their emissions to comply with typically annual emission targets.
Without the legal certainty of future emission levels afforded by the hard “cap” the environmental objectives of the program may not be achieved. In contrast, programs that use emissions fees or taxes (e.g. a carbon tax) impose no legal obligation on the number of tons that can be emitted and thus provide no assurance that specific emissions targets would be achieved.
The second component in a cap and trade program is a market-based emissions trading system. An emissions trading system, which has become synonymous with the “trade” component in a cap and trade program, is created and regulated by government and provides for the use of emissions permits or “allowances” as a form of compliance with the stated emissions caps. Each allowance is the equivalent of one ton of emissions. Companies whose emissions are greater than their allocation or share of the cap are able to purchase allowances to meet their reduction goals. Companies that reduce their emissions more than required by their allocation are able to sell the excess allowances in the open market or to other companies interested in purchasing them. The tradable permit market that ensues from this structure provides clear price signals regarding the value of emissions reductions and allows rational economic decision making and risk management techniques to govern capped sources’ emissions management and control decisions.
Several other notable cost containment mechanisms help to create an even more cost-effective emissions trading system. First is the concept of “banking” emissions allowances. Banking allows companies that are regulated by the program to carry forward unused allowances from previous compliance years and use them to meet future years’ compliance goals. Banking has proven to be an important mechanism in reducing compliance costs because it provides companies with the flexibility of making additional emissions reductions earlier than required in order to avoid some future required reductions when the costs of compliance are much higher.
“Borrowing”, another cost containment mechanism, allows companies to borrow allowances from future compliance periods and submit them for current-year compliance periods. Borrowing was first introduced in the European Union’s Emission Trading System as a means to both reduce compliance costs and dampen allowance price volatility. The creation of a “strategic reserve” of allowances is another cost-containment mechanism by which allowance price volatility and compliance costs can be mitigated. The concept of a strategic reserve has been incorporated into several recent U.S. climate bills. The reserve would help stabilize market prices by injecting additional allowances into the market when market prices reached the reserve’s minimum auction price.
Another important mechanism of an emissions trading system, particularly with regard to greenhouse gases emissions, is the concept of an “offset”. Offsets represent actual, verified emission reductions made by greenhouse gas emitting sectors that cannot practicably be included under the cap. Examples include the U.S. agricultural and forestry sectors and certain sectors within developing countries. By utilizing market incentives, qualifying projects are able to reduce their overall emissions at a relatively low cost. Offsets are important because companies regulated by an emissions cap are able to purchase offset credits and use them towards their own compliance goals, generally at a cost lower than either purchasing allowances or pursuing more costly internal abatement options. Most economists and analysts expect that offsets will be a low-cost way for companies to meet their compliance goals by allowing them to access equivalent lower cost reductions outside of the cap, while achieving the same aggregate reduction of emissions. Offsets are a viable part of greenhouse gas emission programs since the effects of GHG emissions are the same wherever they are emitted in the world, unlike the case for the local or regional pollutants such as SO2 and NOx. Offsets also provide a valuable temporal bridge, allowing early emissions reductions objectives to be met at reasonable cost while new clean energy technologies are developed and available for commercial-scale deployment.
International offsets are also particularly important because of their relatively low cost and, critically, their role in providing incentives for the sustainability of tropical rain forests and the promotion of low-emitting technology in developing countries.
3. Discussion on cost effectiveness and environmental benefits of Cap-and-trade system –
* The U.S. Acid Rain Program is the most mature example of how a cap and trade system works to both reduce the cost of compliance and also meet and even exceed environmental targets.
* The European Union Emission Trading Scheme is the cornerstone of the EU’s successful effort to meet its emissions reduction obligation under the Kyoto Protocol. While the ETS cap nominally covers only approximately 40% of the emissions from the EU, the EU carbon market, particularly the flexibility provided by the use of offsets through the Clean Development Mechanism, has allowed the EU member-states to use international offsets to achieve reductions from sectors not covered by the trading program.
4. Summary of mechanism of Carbon Cap-and-Trading and related aspects –
Cap-and-trade schemes are the most popular way to regulate carbon dioxide (CO2) and other emissions. The scheme’s governing body begins by setting a cap on allowable emissions. It then distributes or auctions off emissions allowances that total the cap. Member firms that do not have enough allowances to cover their emissions must either make reductions or buy another firm’s spare credits. Members with extra allowances can sell them or bank them for future use. Cap-and-trade schemes can be either mandatory or voluntary.
A successful cap-and-trade scheme relies on a strict but feasible cap that decreases emissions over time. If the cap is set too high, an excess of emissions will enter the atmosphere and the scheme will have no effect on the environment. A high cap can also drive down the value of allowances, causing losses in firms that have reduced their emissions and banked credits.
If the cap is set too low, allowances are scarce and overpriced. Some cap and trade schemes have safety valves to keep the value of allowances within a certain range. If the price of allowances gets too high, the scheme’s governing body will release additional credits to stabilize the price. The price of allowances is usually a function of supply and demand.
Credits are similar to carbon offsets except that they’re often used in conjunction with cap-and-trade schemes. Firms that wish to reduce below target may fund pre-approved emissions reduction projects at other sites or even in other countries.
5. Working of Carbon Credits –
As stated above, carbon credits are reductions of emissions of greenhouse gases caused by a project or a Product utilized by anybody which directly or indirectly reduces or eliminates green house gases. Currently this reduction is measured in terms of CO2 reduced. Thus ‘One carbon credit’ is equivalent to ‘One ton’ reduction of CO2.
Now Carbon Credits can be obtained by undertaking new projects under Joint Implementation (JI) with funding agencies or through usage of Products or Projects under Clean Development Mechanism (CDM). In JI, carbon credits are officially called Emission Reduction Units or ERUs. In the CDM, they are called Certified Emission Reductions or CERs. CO2e (Carbon dioxide equivalent)is the same as a carbon credit, ERU or CER.
Companies in countries buy the emission reduction achieved (carbon credits) that are realized through investment in JI or through CDMs and that otherwise would not have existed. Prices are realised by process of competitive bidding.
Carbon credits may be generated from Investments and Projects in renewable energy, energy efficiency, fuel switch and waste management projects.
5.1. CDM projects for Carbon credit purposes –
Some of the fields where Carbon Credits or CER can be generated through implementation of CDM Projects:
* Energy Supply: Renewable energy (e.g. wind mills) – biomass (heat and/or power) and cogeneration.
* Fuel switch: Switching the fuel for Boilers, Furnaces or Power Plants from Coal or Conventional fuel Oils to biomass or Eco-friendly fuels)
* Energy demand: Replacement of existing electrical equipment with more efficient units and improvement of energy efficiency of existing production equipment.
* Transport: Using more efficient engines for transport (e.g. replacing old diesel trains by modern diesel trains) or through transport model shift (e.g. from plane to train) and fuel switch (e.g. public transport buses fuelled by natural gas or Bio-fuels)
* Waste management: Capture of landfill methane emissions & utilisation of waste and wastewater emissions.
* Domestic Utilities: Improving energy efficiency by replacing existing equipment and installing new efficient, new water pumps etc.
* Forestry: Afforestation & Reforestation or Plantation of Eco-friendly plants.
* Carbon capture and storage (CCS): This Technology allow emissions of carbon dioxide to be ‘captured’ and ‘stored’ – preventing them from entering the atmosphere.
5.2. Benefits of Carbon Credits –
* Provide an additional source of revenue
* Improve the return on investments in Projects
* Boost the economic feasibility of projects
* Accelerate project implementation
* Contribution towards the fight against Global warming.
5.3. Buying carbon credits reduces emissions –
Carbon credits create a market for reducing greenhouse emissions by giving a monetary value to the cost of polluting the air. Emissions become an internal cost of doing business and are visible on the balance sheet alongside raw materials and other liabilities or assets.
By way of example, consider a business that owns a factory putting out 100,000 tonnes of greenhouse gas emissions in a year. Its government is an Annex I country that enacts a law to limit the emissions that the business can produce. So the factory is given a quota of say 80,000 tonnes per year. The factory either reduces its emissions to 80,000 tonnes or is required to purchase carbon credits to offset the excess.
After costing up alternatives the business may decide that it is uneconomical or infeasible to invest in new machinery for that year. Instead it may choose to buy carbon credits on the open market from organizations that have been approved as being able to sell legitimate carbon credits.
* One seller might be a company that will offer to offset emissions through a project in the developing world, such as recovering methane from a swine farm to feed a power station that previously would use fossil fuel. So although the factory continues to emit gases, it would pay another group to reduce the equivalent of 20,000 tonnes of carbon dioxide emissions from the atmosphere for that year.
* Another seller may have already invested in new low-emission machinery and have a surplus of allowances as a result. The factory could make up for its emissions by buying 20,000 tonnes of allowances from them. The cost of the seller’s new machinery would be subsidized by the sale of allowances. Both the buyer and the seller would submit accounts for their emissions to prove that their allowances were met correctly.
5.4. Procedure for Obtaining Carbon Credits –
Before you can sell carbon credits you first of all, look into areas where you can reduce emissions and be eco-friendly, then identify and plan a suitable CDM project and determine how much your project reduces emissions. Prior to this you define a baseline, which is a scenario in which you provide supporting evidence about what the emission of greenhouse gases would be until 2012 without your investment. You compare this baseline with the lower emission that will be achieved through your investment. The difference between them is the amount of saleable carbon credits.
In the case of JI projects you can only sell the reduction achieved between 2008 and 2012 and not what you achieved in the previous years or years after.
5.5. Certification requirements under Carbon Credits –
A validation or certification organisation, acting as an independent third party, validates the baseline you have drawn up. This organisation must work according to the “Accreditation Guidelines on the Application of EN 45004 (ISO/IEC Guide 17020) for the Validation and Verification of JI projects” or according to the guidelines of the UNFCCC Executive Board Accreditation Panel for CDM projects.
The host country’s government must give approval for the transaction in carbon credits through a Letter of Approval. However, even if there is a MOU with the country in which you want to invest, you will have to obtain this letter from this country’s government yourself or through an Accreditated Agency.
The payback mechanism under the Kyoto Protocol is a system called carbon credits that are traded like stocks and bonds. The ones who are selling are companies that use clean technology and those doing the buying are the world’s polluters like the Industries, Power Plants, Aviation and the energy sector.
A company that wants to earn from reducing green house gas emissions can get itself certified from the Indian government and the UN body monitoring climate change.
Then it can sell the credit it earns from reducing emissions to another company that’s failed to achieve the Kyoto target or to a company that trades using the generated Carbon Credits. Thus the idea behind carbon trading is quite similar to the trading of securities or commodities in a marketplace. Carbon is given an economic value, allowing companies, agencies or governments to buy, sell, bank and trade Carbon Credits called Certified Emission Reductions or CERs.
6. Carbon credit and management of Carbon footprint –
Since GHG mitigation projects generate credits, this approach can be used to finance carbon reduction schemes between trading partners and around the world. There are many companies that sell carbon credits to commercial and individual customers who are interested in lowering their carbon footprint on a voluntary basis. These carbon offsetters purchase the credits from an investment fund or a carbon development company that has aggregated the credits from individual projects. The quality of the credits is based in part on the validation process and sophistication of the fund or development company that acted as the sponsor to the carbon project. This is reflected in their prices.
7. Conclusion –
Some of the world’s leading climate scientists are sceptic and opine that, we need to be far more active in cutting carbon emissions, urgently. Currently, atmospheric CO2 levels are at 383ppm and we need to go back to 350ppm if we want to keep our globe liveable. This implies a range of technologies that actively remove CO2 from the atmosphere, such as reforestation, carbon-negative bio-energy etc. They say, we must use biological means to tackle a crisis that could otherwise end in a catastrophe much earlier than expected. They even warned that, the world needs innovative, biological ways to reduce carbon dioxide as emissions trading by itself isn’t nearly enough to address the climate crisis. Global warming risks with a sudden climate shift triggered by events such as a rapid release of methane from melting permafrost would be havoc. If such an event happens, there is nothing man can do. This is why we need to act now. The potential costs of inaction are far too great.
* Economics of Greenhouse Gas Trading: Reaching Economic Goals Cost Effectively, International Emissions Trading Association (IETA),
* Carbon Taxes vs Carbon Trading, PricewaterhouseCoopers – March 2009,
* United States Environmental Protection Agency (1999), Progress Report on the EPA Acid Rain Program, 1999.
* Nielson, Leslie (2009), Emissions Trading: Has it worked, Parliament of Australia, Parliamentary Library
* European Environment Agency (2008), Climate for a transport change: Term 2007 indicators tracking transport and environment in the European Union
* Napolitano, Sam, Stevens, Gabrielle, Schreifels, Jeremy, Culligan, Kevin (2007), The NOx Budget Trading Program: A Collaborative, Innovative Approach to Solving a Regional Air Pollution Problem, The Electricity Journal, Volume 20, Issue 9, November 2007.
* Ellerman, Denny (2007), Are Cap-and-Trade Programs More Environmentally Effective than Conventional Regulation?, In Freeman, Jody and Charles D. Kostad (eds.), Moving to Markets in Environmental Regulation: Lessons from Twenty Years of Experience. New York: Oxford University Press, 2007
* Burtraw, D. (1998), Cost Savings, Market Performance, and Economic Benefits of the U.S. Acid Rain Program. Resources for the Future, April.
* IMF (2008), ‘Climate change and the global economy’, Chapter 4 in World Economic Outlook, April 2008.
* PricewaterhouseCoopers (2006), ‘Carbon Taxes: Background and Issues’.
ife-Cycle Assessment (LCA) – A tool for quantifying Sustainability and sound methodology for describing Environmental Impacts
The realisation of the vulnerability of the earth’s eco-systems has led to the design of new initiatives that aim to both assess and address an activity’s impact upon the environment. Current knowledge nevertheless provides a conflicting basis for quantifying sustainability, as central issues such as resource use and resultant impact remain largely unresolved.
As environmental awareness has grown considerably during recent years, industry has been confronted with an ever-increasing demand for information about the management of its environment. The general public has concerns about a wide number of environmental issues such as the safety of plant, transport and products, pollution, and global sustainability. Public authorities increasingly demand information regarding the environmental impact of industrial activities. Society has the right to ask for this information and industry must plan for a future where there will be an ever-increasing spotlight on environmental issues. If the concerns and demands are not addressed then new plants and expansions will be blocked and new products will be rejected. There will be growing regulation and environmental taxation. Insurance and financing costs will rise. And a poor environmental image will make it difficult to attract new people into the industry. Thus it is in the self-interest of industry to work for the environment. For industry to be successful in the future it must demonstrate that it understands the environmental impact that it makes.
The general consensus remains that society must keep its activities within the Earth’s true “carrying capacity” [UNEP 1991]. To this end well-established practices such as energy
audits, risk assessments, and mass balance exercises have evolved to become encompassed under a collective methodology of Life Cycle Assessment (LCA), which may be defined as: “the compilation and evaluation of inputs, outputs and potential environmental impacts of a product system throughout its life-cycle” [ISO 1997].
Thus, Life Cycle Assessment is considered to provide a sound methodology for describing environmental impact.
* To allow our industry to provide relevant information about its environmental impact, to promote best available technologies from an environmental point of view
* To communicate how the industry activity is sustainable in terms of the environment
In other words, as a concept LCA targets the entire cradle to grave activities of a product or process; from the extraction and processing of raw materials to transportation and use, in addition to reviewing the issue of material re-use and final disposal. LCA therefore identifies the system processes and potential environmental burdens throughout a product’s life-cycle.
Moreover as a philosophy, LCA is employed in order to attain the environmental goals of replacing ecologically damaging systems, reducing reliance on finite resources and minimising material waste. This has arguably resulted in LCA being perceived as a panacea for all environmental ills and is increasingly considered as a key tool for the justification and implementation governmental policies on sustainability
What is Life Cycle Assessment?
Life cycle assessment is a relatively new technique. As explained earlier, it aims to account for the environmental burdens created by a product or a service throughout its whole life cycle – “from cradle to crave”. The technique had its origin in the energy studies in the late 1960s and in the early 1970s. Today it is a developed, standardised tool for environmental assessments. LCA evaluates from the environmental point of view all the resources and inputs needed for the system studied and all the outputs from the system, which are emissions to air, water and soil. LCA does not address the economic or social aspects of a product. Life cycle assessment covers the whole product system from raw material acquisition, transportation, material and product manufacture, product use and maintenance and recycling to final disposal. LCA provides a new point of view towards a product system and it can totally change the market profile of the product. A very bad eco-profile can even destroy a product. In the future environmental costs will be more and more transferred to the product price. So it will be beneficial to produce and buy products with lower environmental costs.
In other words, LCA is the assessment of the environmental impact of a product throughout its life cycle. The goal of LCA is to compare the environmental performance of products and services, to be able to choose the least burdensome one. The term ‘life cycle’ refers to the notion that a fair, holistic assessment requires the assessment of raw material production, manufacture, distribution, use and disposal including all intervening transportation steps. This is the life cycle of the product. The concept also can be used to optimize the environmental performance of a single product (ecodesign) or to optimize the environmental performance of a company. The term ’emergy’ is often used as an analysis tool to determine embodied energy.
The pollution caused by usage also is part of the analysis. For a hydro electric power plant, for example, construction pollution is considered, but so is the decay in biomass on land flooded to create the dam because it cannot absorb CO2 anymore. This biomass decay is called “CO2 equivalent”. Common categories of assessed damages are global warming (greenhouse gases), acidification, smog, ozone layer depletion, eutrophication, ecotoxic and anthropotoxic pollutants, desertification, land use as well as depletion of minerals and fossil fuels.
LCA as a tool
In seeking to achieve the utopian ideal of placing all activities in a hierarchy of sustainability, the application and assessment of LCA must be carried out in a consistent manner. However the complex interactions experienced within all life-cycles often preclude detailed comparative analysis of differing functions, be they products or processes. As the very nature of industrial or organic system processes impede the formulation of rigid methodological rules, each activity often requires incompatible criteria of assessment. In order to address the inherent weaknesses experienced in the quantification and qualification of environmental data, a standardised framework is required.
LCA may be utilised for several purposes:
* To identify opportunities to improve the environmental aspects of a product and to find out the weak points in the product chain, where the changes are needed.
* For selection of relevant indicators of environmental performance.
* For product development for environmentally better products.
* For decision making in governmental organisations.
* For product comparisons and product selections.
* For development of specifications, regulations or purchase routines.
* For marketing
The European Union has selected LCA method as one of the “official” methods for environmental evaluation. Also the European standardisation organisation, CEN, has highlighted the importance of the environmental aspects. CEN recognises that every product has impact on the environment during all phases of its life and it has started a system, where each new product standard is attached with a temporary environmental annex. For this annex life cycle assessment is a central tool.
LCA methodology and ISO 14 040 series
Standardisation of LCA methodology is under preparation. The fi rst two standards in the ISO 14 040 series have already been published and the two others are under debate. The standards are:
* ISO 14 040 Life cycle assessment – Principles and framework.
* ISO 14 041 Life cycle assessment – Goal and scope defi nition and inventory analysis.
* ISO 14 042 Life cycle assessment – Life cycle impact assessment.
* ISO 14 043 Life cycle assessment – Life cycle interpretation.
The LCA method can be divided into three basic steps: goal and scope definition, inventory analysis and impact assessment as illustrated below.
The methodology for the two first steps is relatively well established while the third step of impact assessment is more difficult and controversial. Goal and scope definition and inventory analysis are usually referred to as the Life Cycle Inventory or LCI. This part of study can be done separately without impact assessment. If the inventory part of the study is not driven to the final disposal, but to a certain stage of the product life cycle, for example polymer pellets at the factory gate, the study is called as a partial life cycle inventory or eco-profile. This is what many of the producers prepare from their own product, because the product route is known and managed by the producer to this point. The user of the product may further build on the eco-profile and calculate his own eco-profile depending on his specific application.
The first step in the LCA method is the goal and scope definition. The goal definition states clearly the intended application of the study, the reasons for carrying out the study and the intended audience.
For the scope the following items should be clearly described:
* The product system to be studied.
* The functional unit.
* The product system boundaries.
* Allocation procedures, assumptions made and limitations.
* Data requirements.
The second step in the LCA method is the inventory analysis, which involves data collection and calculation procedures to quantify inputs and outputs of the system. These inputs and outputs are the use of natural resources e.g. raw materials, use of energy and emissions to air, water and soil. The life cycle inventory must be clearly described and the system must be transparent.
The third part of the life cycle assessment, impact assessment, is qualitative by nature. It is difficult and the methodology is still under development. At this stage the process followed is to evaluate the significance of environmental impacts by associating inventory data with specific environmental impacts and attempting to understand those impacts. But there are no generally accepted methods for associating inventory data with specific environmental impacts. So this part of the process is generally not included in environmental impact assessments.
Life cycle assessment studies are always iterative processes, where interpretation of the results is done all the time. This may have an effect on the earlier parts of the study, which may be revised based on later findings. Findings in the interpretation phase may also lead to conclusions and recommendations to take improvement actions. Directly the LCA process does not give any final answers or improvement plans. Normally the result of the LCA process is one of many factors affecting a final purchasing decision like technical performance, economic and social aspects.
Summary of the procedure of LCA
Life-cycle assessment is the most standardized and quantified evaluation methodology of those compared. The evaluation typically proceeds as follows:
* Goal and scope definition. This includes the purpose of the study, the system boundaries, and the functional unit of comparison. A material and energy flow chart is also mapped.
* Life-cycle inventory (LCI). In this phase, all information on emissions and the resource consumption of the activities in the system under study are catalogued.
* Life-cycle impact assessment (LCIA). In this phase, the environmental consequences of the inventory are assessed and sensitivity analyses of the results are developed. This typically includes aggregation of the inventory into impact categories (Table 1).
Table 1: LCA Impact categories
* Interpretation. This fourth but controversial step occasionally included by some LCA methods is the interpretation of the results, which may include normalization, weighting and/or additional aggregation.
Discussion – Comparison of LCA with Environmental Impact Assessment (EIA) –
Environmental impact assessment is generally a more familiar method in the US, as it is often a bureaucratically required process used to insure that environmental and other non-monetary concerns are considered in the process of planning government funded or regulated projects. EIA is a process of identifying, predicting, evaluating, and mitigating the biophysical, social, and other relevant effects of proposed projects or plans and physical activities prior to major decisions and commitments being made.
* The primary difference between environmental impact assessment and life-cycle assessment is that EIA is a framework for conducting assessments, not a precise method for analysis. For most practical purposes, LCA is associated with specific methods of analysis. Within EIA there are no assigned or standardized categories or methods of analysis for those categories.
* This difference is due to differences in the scope of assessment between EIA and LCA. EIA generally addresses more localized impacts and allows for the most appropriate methods for the uniqueness of the site and significant impacts. The standard LCA methods, on the other hand, are virtually incapable of detailing most local impacts, but generally provide the most reliably complete quantification of net environmental impact from a regional or global perspective.
Pollution Prevention (P2) Planning – Essential for Management of Green Biz
1. Introduction – Pollution prevention is defined as “use of processes, practices, materials, products, substances or energy that avoids or minimizes the creation of pollutants and waste and reduces the overall risk to the environment or human health”. Pollution prevention planning is a systematic, comprehensive method of identifying and implementing pollution prevention options to minimize or avoid the creation of pollutants or waste. The plan would also identify recycling, treatment and other measures needed to meet environmental goals.
Generally, every nation gives their Environment Ministry the authority to require the preparation and implementation of pollution prevention plans. To invoke these requirements, the Minister publishes notices requiring persons to prepare and implement plans for a substance or group of substances.
In fact, for an organization, Pollution Prevention (P2) Planning is a process by which it can improve their environmental protection by strategically planning to reduce or eliminate pollution before it is created. P2 is a proactive component of an environmental management approach as shown in the pollution prevention hierarchy. The hierarchy provides options and a prioritization mechanism to achieve solutions to environmental protection.
* Pollution should be prevented or reduced at the source whenever feasible;
* Pollution that cannot be prevented should be recycled in an environmentally safe manner whenever feasible;
* Pollution that cannot be prevented or recycled should be treated in an environmentally safe manner whenever feasible; and
* Disposal or other release into the environment should be employed only as a last resort and should be conducted in an environmentally safe manner.
2. Steps for developing a facility Pollution Prevention plan –
Step 1: Develop pollution prevention goals – The first step in preparing a facility pollution prevention plan is to develop goals. These goals will identify specific reductions and accomplishments that you envision for the facility’s pollution prevention program. Some recommended goals might include the following:
* Reductions in the release and use of toxic and extremely hazardous chemicals at your facility,
* Reductions in the release and use of other pollutants as identified by your agency’s pollution prevention strategy
* Reductions in the unnecessary purchase of toxic and hazardous chemicals
* Affirmative procurement practices to ensure the purchase of recycled content materials
* Increases in the volumes of materials captured for recycle
* Reductions in the generation of solid wastes
* Reduction in the consumption of materials, water, and power
* Reductions in the use and release of toxic chemicals to environmental justice areas where socioeconomic factors are of concern
By setting goals, you will define the nature of the pollution prevention program and direct its initial efforts toward a quantifiable objective. As you develop the facility pollution prevention plan, you may identify new goals or modify original goals.
Step 2: Obtain Management Commitment – When management is committed to pollution prevention, the development (and implementation) of the program plan proceeds more smoothly. As with any new project, obtaining management support for pollution prevention involves providing managers with the information they need to make decisions. Managers should understand the reasons for developing a pollution prevention plan, and the elements of a pollution prevention program.
To obtain upper management commitment, you have to sell the concept. To do that, you have to convince managers that a pollution prevention facility plan will help the facility mission by:
* Improving compliance with all applicable environmental requirements, regulations, and Executive Orders
* Reducing operation costs with respect to waste management and the purchase of raw materials
* Reducing the facility’s chances of creating environmental contamination that may result in environmental liabilities and large-scale cleanup requirements
* Improving the productivity of staff by providing a cleaner, healthier working environment through reduced use of toxic materials
* Increasing efficiency through innovative pollution prevention techniques identified and implemented under the pollution prevention program.
Step 3: Establish a Pollution Prevention Team – Realize that various facility staff should participate in the planning process because they will ultimately be responsible for implementing pollution prevention options. You will need assistance from staff who understand and operate different processes or missions at the facility. These staff will be invaluable in defining facility-wide characteristics and pollution prevention opportunities.
Step 4: Develop a Baseline – Developing an environmental baseline involves building a comprehensive picture of the materials usage patterns and environmental impacts associated with the facility. To develop a complete baseline, you will have to collect various information and assimilate it into a unified, multimedia description of your facility’s environmental impacts. The baseline will define materials usage patterns and the environmental problems that arise from these usage patterns. To obtain this information, you will search and review data with the operations staff who are tasked to support this effort. Specifically, each waste generating operation should have one point of contact who can provide baseline statistics that represent that operation.
Step 5: Conduct Pollution Prevention Activities and Opportunity Assessments – You are required to identify pollution prevention activities and conduct opportunity assessments as part of your pollution prevention plan. Using the baseline data, you can identify potential pollution prevention activities and opportunities. For example, the baseline may indicate that water usage is a critical issue for a facility. If water is a critical issue, what activities can be initiated to reduce usage, waste, and overall cost? For every issue documented under the baseline, the team should identify activities that will promote pollution prevention. In general, these activities will include the following:
* Additional Analysis – The baseline may indicate that a process or environmental impact is not fully understood and that more complete information or data are needed. To fully characterize the problem, the staff will have to conduct analyses, analytical measurements, or studies. Upon completion of these analyses, the staff will assess pollution prevention opportunities.
* Immediate Implementation – The baseline may provide applications of existing pollution prevention strategies, techniques, or technologies that can be implemented immediately to reduce environmental impacts. In such cases, the facility may seek to implement pollution prevention options immediately.
* Pollution Prevention Opportunity Assessments – The baseline may also show that processes may be amenable to pollution prevention options. To define the best option, the staff should conduct a thorough pollution prevention opportunity assessment
Step 6: Develop Criteria & Rank facility-wide Pollution Prevention Activities – The next step is to develop priorities and rank the activities. The following considerations are commonly used to rank such activities:
* Environmental Compliance – The project’s impact on improving the facility’s overall environmental compliance status. Special emphasis should be given on identifying and implementing pollution prevention projects that improve compliance.
* Mission Impact – The project’s potential impact on the facility’s mission and the ability of the staff to accomplish their mission.
* Environmental Benefits – The project’s environmental benefits (e.g., air emission reduction, hazardous waste minimization).
* Ease of Implementation – Complex changes that require additional staff effort may not be accepted as easily as simpler changes.
* Cost Savings – the potential cost savings associated with project implementation. Pollution prevention techniques that result in improved efficiency and cost savings are usually accepted more readily than options that result in increased costs.
Step 7: Conduct a Management Review – During management review, the pollution prevention team should present the ranked list of activities for approval. You should explain the process used to develop the list and emphasize the potential benefits of the effort. Upper management must understand the relationship between the pollution prevention program activities and their impacts on the facility mission and existing environmental programs. The end product of this review should be a coherent, integrated pollution prevention program that supplements other facility programs (e.g., safety and occupational health, environmental compliance, training, and development).
3. Basic requirements of a Pollution Prevention (P2) Plan for Industry – Industrial pollution prevention plan should include following points:
* Policy Statement – Develop a policy statement expressing management support for eliminating or reducing the generation or release of toxic chemicals (pollutants) at the facility. Use the policy to set a measurable goal that makes sense for your company and use these overarching goals to set specific reduction objectives for each chemical. Meeting these kinds of goals will directly benefit companies. Reducing chemical releases and transfers are natural outcomes of meeting these kinds of goals. For many companies, the goals of improving quality and productivity will give the greatest return.
Well-designed goals follow the SMART approach. They are specific, measurable, acceptable, realistic and timed.
* Processes – Describe the current processes generating or releasing toxic chemicals (pollutants). Specify the types, sources, and quantities of toxic chemicals (pollutants) currently being generated or released by the facility.
Identify specific sources and causes of waste. Most processes can be broken down into steps then substeps. The substeps can help identify individual sources of releases, or they can be evaluated for factors that affect chemical use.
A flow chart/process flow diagram/process map can be a useful tool for describing and understanding a process. Process flow diagrams can help identify, prioritize and document waste volumes and causes, or sources of inefficiency and cost.
Inputs and outputs for individual operations or steps should be measured directly or carefully estimated. Once process steps are described as finely as possible, you should have identified process steps causing the waste, release or loss.
Next identify the specific sources of each waste or loss for the operation by analyzing its root causes.
* List Options – Write a description of the current and past practices used to eliminate or reduce the generation or release of toxic pollutants at the facility and an evaluation of the effectiveness of these practices.
* Assess Options – Assess the technically and economically feasible options available to eliminate or reduce the generation or release of toxic chemicals (pollutants) at the facility, including options such as changing the raw materials, operating techniques, equipment and technology; personnel training; and other practices used at the facility.
* Objectives and Timeline – State objectives and develop a schedule for achieving those objectives. Companies should express objectives in numeric terms wherever technically and economically feasible. Otherwise, non-numeric objectives may be stated; however, they must include a clearly stated list of actions designed to lead to establishing numeric objectives as soon as they become feasible.
* List Unfeasible Options – List options that were considered but were not technically or economically feasible.
4. Conclusion – Business and the World economy has much to gain by altering their current practices. Now, manufacturing companies are keen to promote its activities as being sustainable. Interest in pollution prevention and sustainable development has been increasing year by year. P2 planning leads to prevent hazardous and toxic wastes by changing processes, redesigning equipment, and recovering waste for reuse or recycling. Targets should be set by defining responsibilities for achieving goals and means and time frame for achieving them. Structure and responsibility defines effective roles and responsibilities and ensures that the top management provide resources including human resources, specialised skills, technology, and financial resources.
Industrial Dust, Air Pollution and related Occupational Diseases – Nuisance to be controlled for improvement of general environment, safety and health standard:
1.0. Introduction – Air pollution is the presence of high concentration of contamination, dust, smokes etc., in the general body of air man breaths. Dust is defined as particulate matter as “any airborne finely divided solid or liquid material with a diameter smaller than 100 micrometers.” Dust and smoke are the two major components of particulate matter. Car emissions, chemicals from factories, dust, pollen and mold spores may be suspended as particles. Ozone, a gas, is a major part of air pollution in cities. When ozone forms air pollution, it’s also called smog. These materials come from various sources, such as, various industrial processes, paved and unpaved roadways, construction and demolition sites, parking lots, storage piles, handling and transfer of materials, and open areas. Some air pollutants are poisonous. Inhaling them can increase the chances of health problems. In fact, dust when inhaled can increase breathing problems, damage lung tissue, and aggravate existing health problems. In addition to health concerns, dust generated from various activities can reduce visibility, resulting in accidents. Therefore, every federal Govt. has stringent regulations which require prevention, reduction and/or mitigation of dust emissions.
Thus, prime sources of air pollution are the industrial activities or processes releasing large quantity of pollutants in the atmosphere. These pollutants are mainly:
(a) Smoke comes out from various industries like, power plants, chemical plants, other manufacturing facilities, motor vehicles, etc.;
(b) Burning of wood, coal in furnaces and incinerators;
(c) Gaseous pollutants from Oil refining industries;
(d) Dust generated and thrown to general atmosphere by various industries such as cement plants, ore / stone crushing units, mining industries due to rock drilling & movements of mining machineries & blasting etc.;
(e) Waste deposition for landfills which generate methane;
(f) Toxic / germ / noxious gasses and fumes generated from military activities and explosives blasting in mines.
2.0. Mechanism of Adverse Impact of Smoke Pollutant – The main sources of smoke pollutants in urban areas are Petrol / Diesel driven motor vehicles, Fuel combustion in stationary sources including residential, commercial and industrial heating / cooling system and coal-burning power plants etc.
Petrol / Diesel driven motor vehicles produce high levels of Carbon Dioxide (CO2) / Carbon Monoxide (CO), major source of Hydrocarbon (HC) and Nitrogen oxides (NOx). Fuel combustion in stationary sources is the dominant source of Carbon Dioxide (CO2) and Sulfur Dioxide (SO2).
Carbon Dioxide (CO2) – This is one of the major gas pollutants in the atmosphere. Major sources of CO2 are due to burning of fossil fuels and deforestation. Industrially developed countries like USA, Russia etc., account for more than 65% of CO2 emission. Less developed countries with 80% of world’s population responsible for about 35% of CO2 emission. Due to high growth reported from less developed countries in last decade, it is estimated that, the Carbon dioxide emissions may rise from these areas and by 2020 their contribution may become 50%. It has also been seen that, Carbon dioxide emissions are rising by 4% annually.
As ocean water contain about 60 times more CO2 than atmosphere; CO2 released by the industry leads to disturbance of equilibrium of concentration of CO2 in the system. In such a scenario, the oceans would absorb more and more CO2 and atmosphere would also remain excess of CO2. As water warms, ocean’s ability to absorb CO2 is reduced. CO2 is a good transmitter of sunlight, but partially restricts infrared radiation going back from the earth into space. This produces the so-called “Greenhouse Effect” that prevents a drastic cooling of the Earth during the night. This so-called “Greenhouse Effect” is responsible for GLOBAL WARMING. Currently Carbon Dioxide is responsible for major portion of the global warming trend.
Nitrogen oxides (NOx) – They come mainly from nitrogen based fertilizers, deforestation, and biomass burning. Nitrogen oxides contribute mostly as atmospheric contaminants. These gases are responsible in the formation of both acid precipitation and photochemical smog and causes nitrogen loading. These gases have a role in reducing stratospheric ozone.
Sulfur Dioxide (SO2) – Sulfur dioxide is produced by combustion of sulfur-containing fuels, such as coal and fuel oils. SO2 also produced in the process of producing Sulfuric Acid and in metallurgical process involving ores that contain sulfur. Sulfur oxides can injure man, plants and materials. As emissions of sulfur dioxide and nitric oxide from stationary sources are transported long distances by winds, they form secondary pollutants such as nitrogen dioxide, nitric acid vapor, and droplets containing solutions of sulfuric acid, sulfate, and nitrate salts. These chemicals descend to the earth’s surface in wet form as rain or snow and in dry form as a gases fog, dew, or solid particles. This is known as acid deposition or acid rain.
Choloroflurocarbons (CFCs) – Chlorofluorocarbons, also known as Freons, are greenhouse gases that contribute to global warming. CFCs are responsible for lowering the average concentration of ozone in the stratosphere.
Smog – Smog is the result from the irradiation by sunlight of hydrocarbons caused primarily by unburned gasoline emitted by automobiles and other combustion sources. Smog is created by burning coal and heavy oil that contain mostly sulfur impurities.
[For more refer Pollution from Motor Vehicles ]
3.0. Mechanism of air pollution by particulate matters (Fine and Coarse Dust particles) – ‘Fine particles’ are less than 2.5 micron in size and require electron microscope for detection, however, they are much larger than the molecules of Ozone etc., and other gaseous pollutants, which are thousands times smaller and cannot be seen through even electron microscope.
Fine particles are formed by the condensation of molecules into solid or liquid droplets, whereas larger particles are mostly formed by mechanical breakdown of material or crushing of minerals. ‘Coarse particles’ are between 2.5 to 10 micron size, and cannot penetrate as readily as of Fine particle; however, it has been seen these are responsible for serious health hazards. The severity of the health hazards vary with the chemical nature of the particles.
The inhalation of particles has been linked with illness and deaths from heart and lung disease as a result of both short- and long-term exposures. People with heart and lung disease may experience chest pain, shortness of breath, fatigue etc., when exposed to particulate-matter pollutants. Inhalation of particulate matter can increase susceptibility to respiratory infections such as Asthma, Chronic Bronchitis. The general medical term given for such lung diseases is ‘Pneumoconiosis’.
Emissions from diesel-fuel combustion in vehicles / engines / equipments; Dusts from cement plants, power plants, chemical plants, mines are a special problem, specially for those individuals breathing in close proximity to such atmosphere. Cars, trucks and off-road engines emit more than half a million tones of diesel particulate matter per year.
3.1. Controlling Airborne Particulate Matters – Airborne particulate matters (PM) emissions can be minimized by pollution prevention and emission control measures. Prevention, which is frequently more cost-effective than control, should be emphasized. Special attention should be given to mitigate the effects, where toxics associated with particulate emissions may pose a significant environmental risk.
Measures such as improved process design, operation, maintenance, housekeeping, and other management practices can reduce emissions. By improving combustion efficiency in Diesel engines, generation of particulate matters can be significantly reduced. Proper fuel-firing practices and combustion zone configuration, along with an adequate amount of excess air, can achieve lower PICs (products of incomplete combustion). Few following steps should be adhered to control PM:
a. Choosing cleaner fuels – Natural gas used as fuel emits negligible amounts of particulate matter.
b. Low-ash fossil fuels contain less noncombustible, ash-forming mineral matter and thus generate lower levels of particulate emissions.
c. Reduction of ash by coal cleaning reduces the generation of ash and Particulate Matter (PM) emissions by up to 40%.
d. The use of more efficient technologies or process changes can reduce PIC emissions.
e. Advanced coal combustion technologies such as coal gasification and fluidized-bed combustion are examples of cleaner processes that may lower PICs by approximately 10%.
f. A variety of particulate removal technologies, are available – these are (a) Inertial or impingement separators, (b) Electrostatic precipitators (ESPs) , (c) Filters and dust collectors (baghouses), (d) Wet scrubbers that rely on a liquid spray to remove dust particles from a gas stream.
4.0. Dust in cement industry – Its prevention and collection enhances environment standard : The manufacturing of cement involves mining; crushing and grinding of raw materials (mostly limestone and clay); calcinating the material in rotary kiln; cooling the resulting clinker; mixing the clinker with Gypsum; and milling, storing and bagging the finished cement. The cement manufacturing process generates lot of dust, which is captured and recycled to the process. Gasses from clinker cooler are used as secondary combustion air. The process, using pre-heaters and pre-calciners, is both economically and environmentally preferable to wet process because of techno-economic advantages of the energy saving dry system over wet. Certain other solids such as pulverized fly ash from power plants, slag, roasted pyrite residue and foundry sand can be used as additives to prepare blended cement.
a. Dust generation: Generation of fine particulates and dust are inherent in the process; but most are recovered and recycled. The sources of dust emission include clinker cooler, crushers, grinders and material-handling equipments. Material-handling operations such as conveyors result in fugitive dust emission.
b. Prevention and control of dust: The priority in the cement industry is to minimize the increase in ambient particulate levels by reducing the mass load emitted from the stacks, from fugitive emissions, and from other sources. Collection and recycling of dust in the kiln gases in required to improve the efficiency of the operation and to reduce atmospheric emissions. Units that are well designed, well operated, and well maintained can normally achieve generation of less than 0.2 kilograms of dust per metric tonne (kg /t) of clinker, using dust recovery systems. For control of fugitive dust (a) ventilation systems should be used in conjunction with hoods and enclosures covering transfer points and conveyors; (b) Drop distances should be minimized by the use of adjustable conveyors; (c) Dusty areas such as roads should be wetted down to reduce dust generation; (d) Appropriate stormwater and runoff control systems should be provided to minimize the quantities of suspended material carried off site.
c. Mechanical systems for controlling dust: Several mechanical equipments are used in cement manufacturing plant to control / collect dust. These are:
(i) Dust collector – A dust collector (bag house) is a typically low strength enclosure that separates dust from a gas stream by passing the gas through a media filter. The dust is collected on either the inside or the outside of the filter. A pulse of air or mechanical vibration removes the layer of dust from the filter. This type of filter is typically efficient when particle sizes are in the 0.01 to 20 micron range.
(ii) Cyclone – Dust laden gas enters the chamber from a tangential direction at the outer wall of the device, forming a vortex as it swirls within the chamber. The larger articulates, because of their greater inertia, move outward and are forced against the chamber wall. Slowed by friction with the wall surface, they then slide down the wall into a conical dust hopper at the bottom of the cyclone. The cleaned air swirls upward in a narrower spiral through an inner cylinder and emerges from an outlet at the top. Accumulated particulate dust is deposited into a hopper, dust bin or screw conveyor at the base of the collector. Cyclones are typically used as pre-cleaners and are followed by more efficient air-cleaning equipment such as electrostatic precipitators and bag houses.
(iii) Electrostatic Precipitator – In an electrostatic precipitator, particles suspended in the air stream are given an electric charge as they enter the unit and are then removed by the influence of an electric field. A high DC voltage (as much as 100,000 volts) is applied to the discharge electrodes to charge the particles, which then are attracted to oppositely charged collection electrodes, on which they become trapped. An electrostatic precipitator can remove particulates as small as 1 μm (0.00004 inch) with an efficiency exceeding 99 percent.
5.0. Dust in Coal Handling Plant (CHP) and its control systems: Thermal power plants (coal-fired power plants) use coal as their fuel. To handle the coal, each power station is equipped with a coal handling plant. The coal has to be sized, processed, and handled which should be done effectively and efficiently. The major factor which reduces the staff efficiency in operation of coal handling plant is the working environment i.e. a dusty atmosphere and condition. Lots of care is always needed to reduce dust emission. In developing countries, all most all systems used in power station coal handling plants are wet dust suppression systems.
5.1. After dust is formed, control systems are used to reduce dust emissions. Although installing a dust control system does not assure total prevention of dust emissions, a well-designed dust control system can protect workers and often provide other benefits, such as (a) Preventing or reducing risk of dust explosion or fire; (b) Increasing visibility and reducing probability of accidents; (c) Preventing unpleasant odors; (d) Reducing cleanup and maintenance costs; (e) Reducing equipment wear, especially for components such as bearings and pulleys on which fine dust can cause a “grinding” effect and increase wear or abrasion rates; (f) Increasing worker morale and productivity; (f) Assuring continuous compliance with existing health regulations. In addition, proper planning, design, installation, operation, and maintenance are essential for an efficient, cost-effective, and reliable dust control system.
5.2. There are two basic types of dust control systems currently used in minerals processing operations are:
(a) Dust collection system – Dust collection systems use ventilation principles to capture the dust-filled air-stream and carry it away from the source through ductwork to the collector. A typical dust collection system consists of four major components, such as (1) An exhaust hood to capture dust emissions at the source; (2) Ductwork to transport the captured dust to a dust collector; (3) A dust collector to remove the dust from the air; (4) A fan and motor to provide the necessary exhaust volume and energy.
(b) Wet dust suppression system – Wet dust suppression techniques use water sprays to wet the material so that it generates less dust. There are two different types of wet dust suppression:
(i) wets the dust before it is airborne (surface wetting) and
(ii) wets the dust after it becomes airborne. In many cases surfactants or chemical foams are often added to the water into these systems in order to improve performance.
A water spray with surfactant means that a surfactant has been added to the water in order to lower the surface tension of the water droplets and allow these droplets to spread further over the material and also to allow deeper penetration into the material.
i. Surface wetting system: The principle behind surface wetting is the idea that dust will not even be given a chance to form and become airborne. With this method, effective wetting of the material can take place by static spreading (wetting material while it is stationary) and dynamic spreading (wetting material while it is moving). For static wetting, more effective dust suppression arises by increasing the surface coverage by either reducing the droplet diameter or its contact angle. For dynamic spreading, more factors come into play such as the surface tension of the liquid, the droplet diameter, the size of the material being suppressed, and the droplet impact velocity.
ii. Airborne dust capture system – Airborne dust capture systems may also use a water-spray technique; however, airborne dust particles are sprayed with atomized water. When the dust particles collide with the water droplets, agglomerates are formed. These agglomerates become too heavy to remain airborne and settle. Airborne dust wet suppression systems work on the principle of spraying very small water droplets into airborne dust. When the small droplets collide with the airborne dust particles, they stick to each other and fall out of the air to the ground. Research showed that, if a sufficient number of water droplets of approximately the same size as the dust particles could be produced, the possibility of collision between the two would be extremely high. It was also determined that if the droplet exceeded the size of the dust particle, there was little probability of impact and the desired precipitation. Instead, the dust particle would move around the droplet.
5.3. System Efficiency: Over the years, water sprays has established the following facts:
(a) For a given spray nozzle, the collection efficiency for small dust particles increases as the pressure increases;
(b) At a given pressure, the efficiency increases as the nozzle design is changed so as to produce smaller droplets. The efficiency of spray dust capture increases by increasing the number of smaller sized spray droplets per unit volume of water utilized and by optimizing the energy transfer of spray droplets with the dust-laden air.
5.4. Sophisticated system like ‘Ultrasonic Dust Suppression’ systems uses water and compressed air to produce micron sized droplets that are able to suppress respirable dust without adding any detectable moisture to the process. Ideal for spray curtains to contain dust within hoppers. The advantages of using Ultrasonic Atomizing Systems for dust suppression can therefore be summarized as: (a) reduced health hazards; (b) decrease in atmospheric pollution; (c) improved working conditions; (d) efficient operation with minimum use of water.
6.0. Air pollution control devices / equipments for industries, in general – The commonly used equipments / process for control of dust in various industries are (a) Mechanical dust collectors in the form of dust cyclones; (b) Electrostatic precipitators – both dry and wet system; (c) particulate scrubbers; (d) Water sprayer at dust generation points; (e) proper ventilation system and (f) various monitoring devices to know the concentration of dust in general body of air.
The common equipments / process used for control of toxic / flue gases are the (a) process of desulphurisation; (b) process of denitrification; (c) Gas conditioning etc. and (d) various monitoring devices to know the efficacy of the systems used.
7.0. Occupational Hazards / diseases due to expose in dusty and polluted air: There are certain diseases which are related to one’s occupation. These are caused by constant use of certain substances that sneak into air and then enter our body.
(i) Silicosis (Silico-tuberculosis) occurs due to inhalation of free silica, or SiO2 (Silicon dioxide), while mining or working in industries related to pottery, ceramic, glass, building and construction work. The workers get chronic cough and pain in the chest. Silicosis treatment is extremely limited considering a lack of cure for the disease. However, like all occupational respiratory ailments, it is 100% preventable if exposure is minimized.
(ii) Asbestosis is caused by asbestos, which is used in making ceilings. It is also considered as cancer causing agent. Pathogenesis of the disease is characterized as progressive and irreversible, leading to subsequent respiratory disability. In severe cases, asbestosis results in death from pulmonary hypertension and cardiac failure.
(iii) Byssinosis, also referred to as brown lung disease, is an occupational respiratory disorder characterized by the narrowing of pulmonary airways. It is a disabling lung disease, which is marked by chronic cough and chronic bronchitis due to inhalation of cotton fibers over a long period of time.
(iv) Coal worker’s Pneumoconiosis occurs due to inhalation of coal dust from coal mining industry. Also referred to as black lung disease. The workers suffer from lung problems. Apart from asbestosis, black lung disease is the most frequently occurring type of pneumoconiosis . In terms of disease pathogenesis, a time delay of nearly a decade or more occurs between exposure and disease onset.
7.1. Preventive Measures – The most successful tool of prevention of respiratory diseases from industrial dust is to minimize exposure. However, this is not a practical approach from the perspective of industries such as mining, construction/demolition, refining/manufacturing/processing, where industrial dust is an unavoidable byproduct. In such cases, industries must implement a stringent safety protocol that effectively curtails exposure to potentially hazardous dust sources. National Institute for Occupational Safety and Health (NIOSH) recommended precautionary measures to reduce exposure to a variety of industrial dust types.
1. Recognize when industrial dust may be generated and plan ahead to eliminate or control the dust at the source. Awareness and planning are keys to prevention of silicosis.
2. Do not use silica sand or other substances containing more than 1% crystalline silica as abrasive blasting materials. Substitute less hazardous materials.
3. Use engineering controls and containment methods such as blast-cleaning machines and cabinets, wet drilling, or wet sawing of silica-containing materials to control the hazard and protect adjacent workers from exposure.
4. Routinely maintain dust control systems to keep them in good working order.
5. Practice good personal hygiene to avoid unnecessary exposure to other worksite contaminants such as lead.
6. Wear disposable or washable protective clothes at the worksite.
7. Shower (if possible) and change into clean clothes before leaving the worksite to prevent contamination of cars, homes, and other work areas.
8. Conduct air monitoring to measure worker exposures and ensure that controls are providing adequate protection for workers.
9. Use adequate respiratory protection when source controls cannot keep silica exposures below the designated limit.
10. Provide periodic medical examinations for all workers who may be exposed to respirable crystalline silica.
11. Post warning signs to mark the boundaries of work areas contaminated with respirable crystalline silica.
12 Provide workers with training that includes information about health effects, work practices, and protective equipment for respirable crystalline silica.
13. Report all cases of silicosis to Federal / State health departments.
8.0. Preventing damaging effects of air and dust pollution – The prevention of air pollution is world wide concern. There have been many investigations into what causes air pollution and the exact methods that work best in the prevention of air pollution. Through the use of many different methods air pollution is becoming easier to control. It is only through various measures, though, that the prevention of air pollution is possible. The government plays a very important role in prevention of air pollution. It is through government regulations that industries are forced to reduce their air pollution and new developments in technology are created to help everyone do their part in the prevention of air pollution. The government also helps by continuously making regulations stricter and enforcing new regulations that help to combat any new found source of air pollution.
In many countries in the world, steps are being taken to stop the damage to our environment from air pollution. Scientific groups study the damaging effects on plant, animal and human life. Legislative bodies write laws to control emissions. Educators in schools and universities teach students, beginning at very young ages, about the effects of air pollution. The first step to solving air pollution is assessment. Researchers have investigated outdoor air pollution and have developed standards for measuring the type and amount of some serious air pollutants.
Scientists must then determine how much exposure to pollutants is harmful. Once exposure levels have been set, steps can be undertaken to reduce exposure to air pollution. These can be accomplished by regulation of man-made pollution through legislation. Many countries have set controls on pollution emissions for transportation vehicles and industry. This is usually done to through a variety of coordinating agencies which monitor the air and the environment.
In the prevention of air pollution it is important to understand about indoor air pollution. Indoor air pollution may seem like an individual concern, but it actually is not just something to worry about in your own home. Indoor air pollution contributes to outdoor air pollution. Prevention is another key to controlling air pollution. The regulatory agencies mentioned above play an essential role in reducing and preventing air pollution in the environment. In addition, it is possible to prevent many types of air pollution that are not regulated through personal, careful attention to our interactions with the environment. One of the most dangerous indoor air pollutants is cigarette smoke. Restricting smoking is an important key to a healthier environment. Legislation to control smoking is in effect in some locations, but personal exposure should be monitored and limited wherever possible.
9.0. Conclusion – Air pollution prevention efforts of companies have generally focused on both source and waste reduction, and on reuse and recycling. Preventing air pollution within a company’s manufacturing processes remains the key approach. Cleaning and processing, switch to non-polluting technologies and materials, reduced generation of waste water, converting hazardous by-products to non-threatening forms, etc. have been attempted in this regard. Indirect air pollution prevention measures by companies also cover transportation. Examples of such measures include: providing company transportation to employees; offering commuting information and selling public transit passes; and encouraging employees to carpool and use public transportation. Companies have also initiated successful programmes such as the use of bicycles to commute to work, telecomuting, and work-at-home etc. to reduce pollution due to commuting.
It should be noted that, only through the efforts of scientists, business leaders, legislators, and individuals can we reduce the amount of air pollution on the planet. This challenge must be met by all of us in order to assure that a healthy environment exist for ourselves and our children.
Environmental pollution, problems and control measures – Overview
A. Introduction and definition of environmental pollution – We know that, a living organism cannot live by itself. Organisms interact among themselves. Hence, all organisms, such as plants, animals and human beings, as well as the physical surroundings with whom we interact, form a part of our environment. All these constituents of the environment are dependent upon each other. Thus, they maintain a balance in nature. As we are the only organisms try to modify the environment to fulfill our needs; it is our responsibility to take necessary steps to control the environmental imbalances.
The environmental imbalance gives rise to various environmental problems. Some of the environmental problems are pollution, soil erosion leading to floods, salt deserts and sea recedes, desertification, landslides, change of river directions, extinction of species, and vulnerable ecosystem in place of more complex and stable ecosystems, depletion of natural resources, waste accumulation, deforestation, thinning of ozone layer and global warming. The environmental problems are visualized in terms of pollution, growth in population, development, industrialization, unplanned urbanization etc. Rapid migration and increase in population in the urban areas has also lead to traffic congestion, water shortages, solid waste, and air, water and noise pollution are common noticeable problems in almost all the urban areas since last few years.
Environmental pollution is defined as the undesirable change in physical, chemical and biological characteristics of our air, land and water. As a result of over-population, rapid industrializations, and other human activities like agriculture and deforestation etc., earth became loaded with diverse pollutants that were released as by-products. Pollutants are generally grouped under two classes:
(a) Biodegradable pollutants – Biodegradable pollutants are broken down by the activity of micro-organisms and enter into the biogeochemical cycles. Examples of such pollutants are domestic waste products, urine and faucal matter, sewage, agricultural residue, paper, wood and cloth etc.
(b) Non- Biodegradable pollutants – Non-biodegradable pollutants are stronger chemical bondage, do not break down into simpler and harmless products. These include various insecticides and other pesticides, mercury, lead, arsenic, aluminum, plastics, radioactive waste etc.
B. Classification of Environmental Pollution – Pollution can be broadly classified according to the components of environment that are polluted. Major of these are: Air pollution, Water pollution, Soil pollution (land degradation) and Noise pollution. Details of these types of pollutions are discussed below with their prevention measures.
(1) Air Pollution: Air is mainly a mixture of various gases such as oxygen, carbon dioxide, nitrogen. These are present in a particular ratio. Whenever there is any imbalance in the ratio of these gases, air pollution is caused. The sources of air pollution can be grouped as under
(i) Natural; such as, forest fires, ash from smoking volcanoes, dust storm and decay of organic matters.
(ii) Man-made due to population explosion, deforestation, urbanization and industrializations.
Certain activities of human beings release several pollutants in air, such as carbon monoxide (CO), sulfur dioxide (SO2), hydrocarbons (HC), oxides of nitrogen (NOx), lead, arsenic, asbestos, radioactive matter, and dust. The major threat comes from burning of fossil fuels, such as coal and petroleum products. Thermal power plants, automobiles and industries are major sources of air pollution as well. Due to progress in atomic energy sector, there has been an increase in radioactivity in the atmosphere. Mining activity adds to air pollution in the form of particulate matter. Progress in agriculture due to use of fertilizers and pesticides has also contributed towards air pollution. Indiscriminate cutting of trees and clearing of forests has led to increase in the amount of carbon dioxide in atmosphere. Global warming is a consequence of green house effect caused by increased level of carbon dioxide (CO2). Ozone (O3) depletion has resulted in UV radiation striking our earth.
The gaseous composition of unpolluted air
Parts per million (vol)
Harmful Effects of air pollution –
(a) It affects respiratory system of living organisms and causes bronchitis, asthma, lung cancer, pneumonia etc. Carbon monoxide (CO) emitted from motor vehicles and cigarette smoke affects the central nervous system.
(b) Due to depletion of ozone layer, UV radiation reaches the earth. UV radiation causes skin cancer, damage to eyes and immune system.
(c) Acid rain is also a result of air pollution. This is caused by presence of oxides of nitrogen and sulfur in the air. These oxides dissolve in rain water to form nitric acid and sulfuric acid respectively. Various monuments, buildings, and statues are damaged due to corrosion by acid present in the rain. The soil also becomes acidic. The cumulative effect is the gradual degradation of soil and a decline in forest and agricultural productivity.
(d) The green house gases, such as carbon dioxide (CO2) and methane (CH4) trap the heat radiated from earth. This leads to an increase in earth’s temperature.
(e) Some toxic metals and pesticides also cause air pollution.
[For more refer Industrial Dust, Air Pollution and Related Occupational Diseases ]
(2) Water Pollution: Water is one of the prime necessities of life. With increasing number of people depend on this resource; water has become a scarce commodity. Pollution makes even the limited available water unfit for use. Water is said to be polluted when there is any physical, biological or chemical change in water quality that adversely affects living organisms or makes water unsuitable for use. Sources of water pollution are mainly factories, power plants, coal mines and oil wells situated either close to water source or away from sources. They discharge pollutants directly or indirectly into the water sources like river, lakes, water streams etc. The harmful effects of water pollution are:
(a) Human beings become victims of various water borne diseases, such as typhoid, cholera, dysentery, hepatitis, jaundice, etc.
(b) The presence of acids/alkalies in water destroys the microorganisms, thereby hindering the self-purification process in the rivers or water bodies. Agriculture is affected badly due to polluted water. Marine eco-systems are affected adversely.
(c) The sewage waste promotes growth of phytoplankton in water bodies; causing reduction of dissolved oxygen.
(d) Poisonous industrial wastes present in water bodies affect the fish population and deprives us of one of our sources of food. It also kills other animals living in fresh water.
(e) The quality of underground water is also affected due to toxicity and pollutant content of surface water.
(2.1) Water pollution by industries and its effects – A change in the chemical, physical, biological, and radiological quality of water that is injurious to its uses. The term “water pollution” generally refers to human-induced changes to water quality. Thus, the discharge of toxic chemicals from industries or the release of human or livestock waste into a nearby water body is considered pollution.
The contamination of ground water of water bodies like rivers, lakes, wetlands, estuaries, and oceans can threaten the health of humans and aquatic life. Sources of water pollution may be divided into two categories. (i) Point-source pollution, in which contaminants are discharged from a discrete location. Sewage outfalls and oil spills are examples of point-source pollution. (ii) Non-point-source or diffuse pollution, referring to all of the other discharges that deliver contaminants to water bodies. Acid rain and unconfined runoff from agricultural or urban areas falls under this category.
The principal contaminants of water include toxic chemicals, nutrients, biodegradable organics, and bacterial & viral pathogens. Water pollution can affect human health when pollutants enter the body either via skin exposure or through the direct consumption of contaminated drinking water and contaminated food. Prime pollutants, including DDT and polychlorinated biphenyls (PCBs), persist in the natural environment and bioaccumulation occurs in the tissues of aquatic organisms. These prolonged and persistent organic pollutants are transferred up the food chain and they can reach levels of concern in fish species that are eaten by humans. Moreover, bacteria and viral pathogens can pose a public health risk for those who drink contaminated water or eat raw shellfish from polluted water bodies.
Contaminants have a significant impact on aquatic ecosystems. Enrichment of water bodies with nutrients (principally nitrogen and phosphorus) can result in the growth of algae and other aquatic plants that shade or clog streams. If wastewater containing biodegradable organic matter is discharged into a stream with inadequate dissolved oxygen, the water downstream of the point of discharge will become anaerobic and will be turbid and dark. Settleable solids will be deposited on the streambed, and anaerobic decomposition will occur. Over the reach of stream where the dissolved-oxygen concentration is zero, a zone of putrefaction will occur with the production of hydrogen sulfide (H2S), ammonia (NH3), and other odorous gases. Because many fish species require a minimum of 4–5 mg of dissolved oxygen per liter of water, they will be unable to survive in this portion of the stream.
Direct exposures to toxic chemicals are also a health concern for individual aquatic plants and animals. Chemicals such as pesticides are frequently transported to lakes and rivers via runoff, and they can have harmful effects on aquatic life. Toxic chemicals have been shown to reduce the growth, survival, reproductive output, and disease resistance of exposed organisms. These effects can have important consequences for the viability of aquatic populations and communities.
Wastewater discharges are most commonly controlled through effluent standards and discharge permits. Under this system, discharge permits are issued with limits on the quantity and quality of effluents. Water-quality standards are sets of qualitative and quantitative criteria designed to maintain or enhance the quality of receiving waters. Criteria can be developed and implemented to protect aquatic life against acute and chronic effects and to safeguard humans against deleterious health effects, including cancer.
[ For more refer ‘Water Conservation – Need-of-the-day for our very survival‘ ]
(3) Soil pollution (Land degradation): Land pollution is due to
(i) Deforestation and
(ii) Dumping of solid wastes.
Deforestation increases soil erosion; thus valuable agricultural land is lost. Solid wastes from household and industries also pollute land and enhance land degradation. Solid wastes include things from household waste and of industrial wastes. They include ash, glass, peelings of fruit and vegetables, paper, clothes, plastics, rubber, leather, brick, sand, metal, waste from cattle shed, night soil and cow dung. Chemicals discharged into air, such as compounds of sulfur and lead, eventually come to soil and pollute it. The heaps of solid waste destroy the natural beauty and surroundings become dirty. Pigs, dogs, rats, flies, mosquitoes visit the dumped waste and foul smell comes from the waste. The waste may block the flow of water in the drain, which then becomes the breeding place for mosquitoes. Mosquitoes are carriers of parasites of malaria and dengue. Consumption of polluted water causes many diseases, such as cholera, diarrhea and dysentery.
[ For more refer Solid Waste Disposal -A Burning Problem To Be Resolved To Save Environment ]
(4) Noise pollution : High level noise is a disturbance to the human environment. Because of urbanization, noise in all areas in a city has increased considerably. One of the most pervasive sources of noise in our environment today is those associated with transportation. People reside adjacent to highways, are subjected to high level of noise produced by trucks and vehicles pass on the highways. Prolonged exposure to high level of noise is very much harmful to the health of mankind.
In industry and in mines the main sources of noise pollution are blasting, movement of heavy earth moving machines, drilling, crusher and coal handling plants etc. The critical value for the development of hearing problems is at 80 decibels.
Chronic exposure to noise may cause noise-induced hearing loss. High noise levels can contribute to cardiovascular effects. Moreover, noise can be a causal factor in workplace accidents.
C. Fundamentals of prevention and control of air pollution:
As mentioned above, air pollutants can be gaseous or particulate matters. Different techniques for controlling these pollutants are discussed below:
a. Methods of controlling gaseous pollutants –
1. Combustion – This technique is used when the pollutants are in the form of organic gases or vapors. During flame combustion or catalytic process, these organic pollutants are converted into water vapor and relatively less harmful products, such as CO2.
2. Absorption – In this technique, the gaseous effluents are passed through scrubbers or absorbers. These contain a suitable liquid absorbent, which removes or modifies one or more of the pollutants present in the gaseous effluents.
3. Adsorption – The gaseous effluents are passed through porous solid adsorbents kept in suitable containers. The organic and inorganic constituents of the effluent gases are trapped at the interface of the solid adsorbent by physical adsorbent.
b. Methods to control particulate emissions –
1. Mechanical devices generally work on the basis of the following:
(i) Gravity: In this process, the particles settle down by gravitational force.
(ii) Sudden change in direction of the gas flow. This causes the particles to separate out due to greater momentum.
2. Fabric Filters: The gases containing dust are passed through a porous medium. These porous media may be woven or filled fabrics. The particles present in the gas are trapped and collected in the filters. The gases freed from the particles are discharged.
3. Wet Scrubbers: Wet scrubbers are used in chemical, mining and metallurgical industries to trap SO2, NH3, metal fumes, etc.
4. Electrostatic Precipitators: When a gas or an air stream containing aerosols in the form of dust, fumes or mist, is passed between two electrodes, then, the aerosol particles get precipitated on the electrode.
c. Other practices in controlling air pollution – Apart from the above, following practices also help in controlling air pollution.
(i) Use of better designed equipment and smokeless fuels, hearths in industries and at home.
(ii) Automobiles should be properly maintained and adhere to recent emission-control standards.
(iii) More trees should be planted along road side and houses.
(iv) Renewable energy sources, such as wind, solar energy, ocean currents, should fulfill energy needs.
(v) Tall chimneys should be installed for vertical dispersion of pollutants.
d. General air pollution control devices / equipments for industries – The commonly used equipments / process for control of dust in various industries are (a) Mechanical dust collectors in the form of dust cyclones; (b) Electrostatic precipitators – both dry and wet system; (c) particulate scrubbers; (d) Water sprayer at dust generation points; (e) proper ventilation system and (f) various monitoring devices to know the concentration of dust in general body of air.
The common equipments / process used for control of toxic / flue gases are the (a) process of desulphurisation; (b) process of denitrification; (c) Gas conditioning etc. and (d) various monitoring devices to know the efficacy of the systems used.
e. Steps, in general, to be taken for reduction of air pollution – To change our behavior in order to reduce AIR POLLUTION at home as well as on the road, few following small steps taken by us would lead to clean our Environment.
1. Avoid using chemical pesticides or fertilizers in your yard and garden. Many fertilizers are a source of nitrous oxide, a greenhouse gas that contributes to global warming. Try organic products instead.
2. Compost your yard waste instead of burning it. Outdoor burning is not advisable, as it pollutes air. Breathing this smoke is bad for you, your family and your neighbors. Plus, you can use the compost in your garden.
3. If you use a wood stove or fireplace to heat your home, it would be better to consider switching to another form of heat which does not generate smoke. It is always better to use sweater or warm clothing than using fireplace.
4. Be energy efficient. Most traditional sources of energy burn fossil fuels, causing air pollution. Keep your home well-maintained with weather-stripping, storm windows, and insulation. Lowering your thermostat can also help – and for every two degrees Fahrenheit you lower it, you save about two percent on your heating bill.
5. Plant trees and encourage other to plant trees as well. Trees absorb and store carbon dioxide from the atmosphere, and filter out air pollution. During warmer days, trees provide cool air, unnecessary use of energy on air conditioning is avoided, hence the air pollution.
6. Try to stop smoking; at home, at office or at outside. Tobacco smoking not only deteriorates self’s health, it affects others health too.
On the Road:
7. Keep your vehicle well maintained. A poorly maintained engine both creates more air pollution and uses more fuel. Replace oil and air filters regularly, and keep your tires properly inflated.
8. Drive less. Walking, bicycling, riding the bus, or working from home can save you money as well as reducing air pollution.
9. Don’t idle your vehicle. If you stop for more than 30 seconds, except in traffic, turn off your engine.
10. Don’t buy more car than you need. Four-wheel drive, all-wheel drive, engine size, vehicle weight, and tire size all affect the amount of fuel your vehicle uses. The more fuel it uses the more air pollution it causes.
D. Water pollution prevention and control:
Water is a key resource for our quality of life. It also provides natural habitats and eco-systems for plant and animal species. Access to clean water for drinking and sanitary purposes is a precondition for human health and well-being. Clean unpolluted water is essential for our ecosystems. Plants and animals in lakes, rivers and seas react to changes in their environment caused by changes in chemical water quality and physical disturbance of their habitat.
Water pollution is a human-induced change in the chemical, physical, biological, and radiological quality of water that is injurious to its existing, intended, or potential uses such as boating, waterskiing, swimming, the consumption of fish, and the health of aquatic organisms and ecosystems. Thus, the discharge of toxic chemicals from a pipe or the release of livestock waste into a nearby water body is considered pollution. The contamination of ground water, rivers, lakes, wetlands, estuaries, and oceans can threaten the health of humans and aquatic life.
Contaminants have a significant impact on aquatic ecosystems. for example, enrichment of water bodies with nutrients (principally nitrogen and phosphorus) can result in the growth of algae and other aquatic plants that shade or clog streams. Direct exposures to toxic chemicals such as pesticides, is also a health concern for individual aquatic plants and animals. Without healthy water for drinking, cooking, fishing, and farming, the human race would perish. Clean water is also necessary for recreational interests such as swimming, boating, and water skiing.
a. Sources of Water Pollution – Sources of water pollution are generally divided into two categories. The first is point-source pollution, in which contaminants are discharged from a discrete location. Sewage outfalls and oil spills are examples of point-source pollution. The second category is non-point-source or diffuses pollution, referring to all of the other discharges that deliver contaminants to water bodies.
Numerous manufacturing plants pour off undiluted corrosives, poisons, and other noxious byproducts to water streams. The construction industry discharges slurries of gypsum, cement, abrasives, metals, and poisonous solvents. The mining industry also presents persistent water pollution problems. In yet another instance of pollution, hot water discharged by factories and power plants causes so-called ‘thermal pollution’ by increasing water temperatures. Such increases change the level of oxygen dissolved in a body of water, thereby disrupting the water’s ecological balance, killing off some plant and animal species while encouraging the overgrowth of others. Towns and municipalities are also major sources of water pollution.
In many public water systems, pollution exceeds safe levels. One reason for this is that much groundwater has been contaminated by wastes pumped underground for disposal or by seepage from surface water. When contamination reaches underground water tables, it is difficult to correct and spreads over wide areas. Discharge of untreated or only partially treated sewage into the waterways threatens the health of their own and neighboring populations as well. Along with domestic wastes, sewage carries industrial contaminants and a growing tonnage of paper and plastic refuse. Although thorough sewage treatment would destroy most disease-causing bacteria, the problem of the spread of viruses and viral illness remains. Additionally, most sewage treatment does not remove phosphorus compounds, contributed principally by detergents.
b. Dangers of Water Pollution – Virtually all water pollutants are hazardous to humans as well as lesser species; sodium is implicated in cardiovascular disease, nitrates in blood disorders. Mercury and lead can cause nervous disorders. Some contaminants are carcinogens. DDT is toxic to humans and can alter chromosomes. Along many shores, shellfish can no longer be taken because of contamination by DDT, sewage, or industrial wastes.
c. Prevention and Control of Water Pollution – Sewage should be treated before it is discharged into the river or ocean. This is possible through modern techniques.
Sewage is first passed through a grinding mechanism. This is then passed through several settling chambers and neutralized with lime. Up to this stage, the process is called primary treatment. The sewage still contains a large number of pathogenic and non-pathogenic organisms, and also sufficient quantity of organic matter. The neutralized effluents are sent to UASB (up-flow anaerobic sludge blanket). It is a reactor. In this, the anaerobic bacteria degrade the biodegradable material present in the waste water. This removes foul odor and releases methane, which can be used elsewhere. In this system, the pollution load is reduced upto 85 percent. After this, water is sent to aeration tanks where it is mixed with air and bacteria. Bacteria digest the organic waste material. This is called biological or secondary treatment. Even after the treatment, water is not yet fit for drinking. The harmful microorganisms need to be killed. The final step (tertiary treatment) is, therefore, a disinfection process, to remove final traces of organics, bacteria, dissolved inorganic solids, etc. For tertiary treatment, methods, such as chlorination, evaporation, and exchange absorption may be employed. These depend upon the required quality of the final treatment.
Apart from the above, you should also adopt the following practices:
(i) Waste food material, paper, decaying vegetables and plastics should not be thrown into open drains.
(ii) Effluents from distilleries, and solid wastes containing organic matter should be sent to biogas plants for generation of energy.
(iii) Oil slicks should be skimmed off from the surface with suction device. Sawdust may be spread over oil slicks to absorb the oil components.
E. Soil erosion and its prevention: Soil erosion by water, wind and tillage affects both agriculture and the natural environment. Soil loss, and its associated impacts, is one of the most important (yet probably the least well-known) of today’s environmental problems. It is mostly due to poor land use practices, which include deforestation, overgrazing, unmanaged construction activity and road or trail building.
Soil is a complex mixture of living and non-living materials. It provides anchorage and sustenance to plants. Natural agents like water and wind, constantly tend to remove the top soil and cause erosion. Rain falling upon the unprotected top soil, washes it down into the streams. Due to the absence of plant covering, eroded soil cannot hold water. Water rushes into the rivers and overflows as flood. Dust storm also causes soil erosion. The particles of top soil are picked up in such quantities that they form clouds of dust. Human beings also cause soil erosion. The growing human habitation and expansion of urban areas lead to removal of vegetation. Once vegetation is removed, the naked soil gets exposed to wind and water. Improper tillage is another cause of soil erosion. Farmers often loosen the top soil for removing weeds and preparing seed beds. They also leave agricultural fields lying fallow for long time. These practices expose the top soil to the wind and cause erosion.
Soil erosion is always a result of mankind’s unwise actions, such as overgrazing or unsuitable cultivation practices. These leave the land unprotected and vulnerable. Accelerated soil erosion by water or wind may affect both agricultural areas and the natural environment, and is one of the most widespread of today’s environmental problems. Soil erosion is just one form of soil degradation. Other kinds of soil degradation include salinisation, nutrient loss, and compaction.
Prevention of soil erosion – Plants provide protective cover on the land and prevent soil erosion for the reasons:
(a) plants slow down water as it flows over the land (runoff) and this allows much of the rain to soak into the ground;
(b) plant roots hold the soil in position and prevent it from being washed away;
(c) plants break the impact of a raindrop before it hits the soil, thus reducing its ability to erode;
(d) plants in wetlands and on the banks of rivers are of particular importance as they slow down the flow of the water and their roots bind the soil, thus preventing erosion.
Preventing soil erosion requires technical changes to adopt. Aspects of technical changes include:
(i) use of contour ploughing and wind breaks;
(ii) leaving unploughed grass strips between ploughed land;
(iii) making sure that there are always plants growing on the soil, and that the soil is rich in humus (decaying plant and animal remains). This organic matter is the “glue” that binds the soil particles together and plays an important part in preventing erosion;
(iv) avoiding overgrazing and the over-use of crop lands;
(v) allowing indigenous plants to grow along the river banks instead of ploughing and planting crops right up to the water’s edge;
(vi) encouraging biological diversity by planting several different types of plants together;
(vii) conservation of wetlands.
We can check soil erosion by adopting the following additional practices:
1. Intensive cropping and use of proper drainage canals.
2. Terracing on the sloping fields. This retards the speed of the flowing water.
3. Planting trees and sowing grasses.
4. Extensive aforestation practices to be carried out.
[ For more refer Soil Erosion Combating is Essential ]
F. Mitigation of Noise pollution: Reducing noise pollution by muffling the sounds at the source is one of the best methods in industry and for urban living. Protective equipment is generally mandatory when noise levels exceed 85 dB(A) in industry. Creation of green cover adjacent to municipal roads and in mines is the way to mitigate noise pollution. It has been observed that noise level reduces by 10 decibels per every 10m wide green belt development. Apart, redesigning industrial equipment, shock mounting assemblies and physical barriers in the workplace are also for reduction and exposure of unwanted industrial noise.
High way noise pollution can be mitigated by constructing noise barriers. Artificial noise barriers are solid obstructions built between the highway and the residential areas along a highway. They block major portion of noise produced by passing vehicles on a highway. Effective noise barriers typically reduce noise levels by as much as half or more. The construction of noise barrier may be built in the form of earth mounds, vertical wall along the highways for creation of blockage of sound generated by heavy vehicles. Creation of greenbelt in the space between the residences and highways also reduces the noise nuisance.
G. Conservation and protection of environment: By now, all of us have realized how important it is to protect the environment for our own survival. The term ‘conservation’ of environment relates to activities which can provide individual or commercial benefits, but at the same time, prevent excessive use leading to environmental damage. Conservation may be distinguished from preservation, which is considered to be “maintaining of nature as it is, or might have been before the intervention of either human beings or natural forces.” We know that natural resources are getting depleted and environmental problems are increasing. It is, therefore, necessary to conserve and protect our environment. Following practices help in protecting our environment.
1. Rotation of crops.
2. Judicious use of fertilisers, intensive cropping, proper drainage and irrigation.
3. Treatment of sewage, so that it does not pollute the rivers and other water bodies.
4. Composting organic solid waste for use as manure.
5. Planting trees in place of those removed for various purposes.
6. National parks and conservation forests should be established by the government.
7. Harvesting of rain water.
Some action points to protect or improve the environment –
(i) Dispose the waste after separating them into biodegradable and non-biodegradable waste material.
(ii) Start a compost heap or use a compost bin. This can be used to recycle waste food and other biodegradable materials.
(iii) Avoid unnecessary or wasteful packaging of products.
(iv) Reuse carry bags.
(v) Plant trees. They will help to absorb excess carbon dioxide.
(vi) Observe World Environment Day on 5th June.
(vii) Never put any left over chemicals, used oils down the drain, toilet or dump them on the ground or in water or burn them in the garden. If you do so, it will cause pollution.
(viii) Don’t burn any waste, especially plastics, for the smoke may contain polluting gases.
(ix) Use unleaded petrol and alternate sources of energy, and keep the engine properly tuned and serviced and the tyres inflated to the right pressure, so that vehicle runs efficiently.
(x) Avoid fast starts and sudden braking of automobiles.
(xi) Walk or cycle where it is safe to do so – walking is free; cycling can help to keep you fit.
(xii) Use public transport wherever you can, or form a car pool for everyday travel.
(xiii) Send your waste oil, old batteries and used tyres to a garage for recycling or safe disposal; all these can cause serious pollution.