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PDF | On Jun 6, , Abdullah Al-Muyeed and others published Water and Water and Environmental Engineering. Book · June with 90, Reads. No part of this ebook may be reproduced in any form, by photostat, microfilm, Environmental engineering is one of the most popular, complex and fast growing . CHAPTER 1 INTRODUCTION TO ENVIRONMENTAL ENGINEERING 1 OBJECTIVES The followings are the objectives of this chapter: 9 Ability to describe.
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Hit a particularly tricky question? Bookmark it to easily review again before an exam. Tchobanoglous et al. For example, ferrous items which are of a large size may be too heavy to be separated by a magnetic belt or drum system. The size of waste components can be determined using one the following equations: It is a critical measure because water in excess of field capacity will form letéléchargemente, and letéléchargemente can be a major problem in landfills.
Permeability depends on the other properties of the solid material including pore size distribution, surface area and porosity. This is especially important where wastes are burned for energy recovery, in which case the four most important properties are proximate analysis, fusing point of ash, elemental analysis, and energy content.
Elemental analysis is also important in determining nutrient availability. Some typical values are shown in Table Because of concern about halogens these are also often determined as well. The results of this analysis are used to characterise the composition of the organic matter in wastes. Typical values are shown in Table The energy content will be looked at later when discussing on incineration.
Of most importance are the major nutrients in their various forms - nitrogen as nitrates, ammonium N phosphorus and potassium.
Example Using the data given in Table The most important biological characteristic of the organic fraction of MSW is that almost all the organic components can be converted biologically to gases and relatively inert organic and inorganic solids.
The production of odours and the generation of flies are also related to the putrescible nature of the organic materials.
These will be discussed when talking about landfill processes. Solid wastes can be transformed by physical, chemical and biological means Table It can include such things as magnetic separation. The usual materials recovered include separation of recyclables, the removal of hazardous wastes, and the recovery of energy products.
Volume reduction refers to the processes whereby waste volumes are reduced, usually by force or pressure. Collection vehicles frequently have compaction mechanisms - or compaction can take place at a transfer station. The baling of plastics, paper, and aluminium is another means of volume reduction, as is the compaction that takes place in landfills.
Pressure can be used, e.
Size reduction is used to reduce the size of wastes. It usually involves some form of shredding, grinding or milling. The main processes are combustion, pyrolysis, and gasification. Combustion is the chemical reaction with oxygen of organic materials accompanied by the emission of light and heat. The process can be represented as: These processes will be examined in more detail later in the course. When carried out anaerobically methane is produced - a typical component of landfill gas.
This will be examined in more detail later. Typically waste transformations are used: The different types of systems mentioned, not only for waste collection but also for the collection of recyclable materials is varied and governed by many factors some of which have nothing to do with waste management. It meant choosing the most appropriate trucks, designing collection routes, and then administering the collection.
With present day emphasis on recycling and composting the need to segregate materials has become most important. It can mean different vehicles collecting different material and taking it to different locations. As a result, the collection of wastes has become more complex and more expensive. To meet current needs there is a call for the development of an 'integrated collection strategy' which incorporates the following: Collection frequency may have to be altered because of weather conditions which can pose health and odour problems.
Increasing collection frequency has considerable cost implications and could lead to doubling of labour costs. Bins are placed near the curb side thus allowing the use of one-person vehicles with extending arms to collect the bins. In some locations, e.
This means extra crews are required with extra labour costs. In some locations the crew actually come into the house yard often around the back to collect the bin. This obviously slows collection times and increases costs. The use of centralised systems, such as apartment blocks, will accelerate collection times by reducing travelling distances and times.
Each type has advantages and disadvantages and must also be related to the set out location. For instance, large wheelie bins will be impractical in narrow urban areas with on-street parking. In New Zealand there is another advantage with bags in that in some districts a special sticker is required to be placed on the bag for costing purposes. Stickers can be easily seen by collection crews.
The use of paper bags can provide advantages in composting in that they are easily shredded. The disadvantages of wheelie bin are one of size - most people put out more rubbish to fill the bin. They also require mechanical lifting arms for health and safety reasons, and cost more initially.
Interestingly, most wheelie bins are made out of recycled plastic. The set out location, size of area to be served, method of collection and costs of vehicles and operators are the major concerns. In most instances, curb side pickup is the most convenient, and the trend in recycling is towards some form of curb side pickup.
Drop-off and download-back centre are not as convenient. Typically, a programme using such centre will have lower participation rates. Most communities and hauling companies face a dilemma in deciding how best to collect recycled materials, especially those with fleets of refuse vehicles. The prospect of replacing a fleet of refuse trucks with an equally expensive fleet of vehicles designed for recycling is normally not economically feasible, at least at first.
As a result, most recycling programmes try to use existing refuse equipment to collect recycled materials. Many innovative ideas have been used to convert refuse trucks to all-purpose refuse collection and recycling vehicles. For example, the city of Madison, Wisconsin, designed a newspaper rack welded to the frame of refuse trucks for the purpose of collecting bundled newspaper.
This low cost adaptation was first designed by city engineers in and is still in use today. The split-bin system in use in Byron Bay is a high-cost method, necessitation new bins and new collection vehicles. In the UK in Luton, a system using cuphooks attached to bins was tried unsuccessfully.
Some companies which haul waste from commercial accounts generating high volumes of office paper or cardboard make no attempt to separate the material. Instead, they substitute back- end sorting and processing for separation before collection, separating recyclables out of the waste stream at a processing centre in what is known as "dump and pick" operation.
Some of these operations have proved successful, although contamination of recycled materials from mixing with other waste can be a problem.
Other communities use refuse trucks in concert with pickup trucks. The pickup follows the large vehicle and collects recycled materials on the same day as normal refuse pick-up. By requiring the use of clear plastic bags for recycled materials - and perhaps supplying them - the mixing of recycled materials with other refuse can be minimised.
In still other communities, recyclables are collected on a different day. As long as public education is continuous, and the pick-up schedule is highly reliable, the public seems willing to follow whatever schedule is established for collecting recyclables. The vehicle use for collection will generally have as many compartments as are required for the different types, usually 3 or 4.
These are sorted by the crew at collection and obviously this involves more labour costs. This system can be varied, e. Sometimes this can also involve a preliminary sorting, e.
A disadvantage is the problem of contamination, especially in a single compartment system. A further disadvantage is that compaction cannot be carried out as well with a loss in efficiency. This is obviously a labour intensive operation, though some materials, e. Already, many communities and waste-service companies use compartmentalised trucks or trailers on collection routes.
There are a variety of vehicle designs on the market, all of which provide efficient and easy loading and unloading of both recovered materials and solid waste. Some communities using special recycling vehicles have enhanced participation rates and collecting efficiency by supplying recycling boxes to homeowners. Similar programmes exist in cities such as Santa Rosa, California, and St. Louis Park, Minnesota, where residents have received stacking plastic containers for paper, glass, and cans from the city or contractor.
Mobile download-back operations are also increasing in number, especially for service of rural areas - which may not produce enough volume to support a private recycling operation. Mobile download-back units often pay for some materials and accept for free other materials. Here it is separated, processed, and stored until enough material has been collected to create a full load for transport to a market.
Material usually must be processed to meet the specifications of downloaders. The centre must be designed to efficiently move the material from the tipping floor or drop-off point through the system to the storage area. Many technologies are available for efficient processing, materials handling, and storage. The choice of equipment and systems must take into account: Glass, which is impervious to weather, can be stored outside; this would require the construction of revetments or concrete storage containers, which is relatively cheap.
Collected glass can be dumped into the revetment compartment or removed by a small tractor. A barrier is often placed at the front of the revetment to ensure that injuries to employees or others do not occur from accidental spillage. Some materials, such as newsprint, cannot be stored outside in the weather indefinitely; to achieve a competitive price for newsprint, one must prevent decomposition. Storage indoors of newspaper and other items can create problems for a poorly designed centre, as there can be a constant struggle between space needed for processing and operations and space requirements for materials storage.
What's more, storage problems can result when either the volume of recycled materials expected is significantly underestimated or the demand for materials already on hand is significantly overestimated. The amount of processing which will be necessary at the recycling centre will depend to a large degree on how the material is collected.
So-called "dump and pick" operations require significant manual labour for extraction of recycled materials from the bulk of the refuse. While some of these operations have workers hand-sort material, hand-sorting can be dangerous for workers, exposing them to hazardous materials and sharp objects contained in the waste.
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Some operations utilise sophisticated sorting technology, including trommels, air classifiers, and conveyers to mechanically separate the waste.
Where waste volumes collected are large, mechanical separation systems may be economic. Even with these systems, some hand-separation is usually needed to ensure recovered materials are free of contamination. Material that enters the recycling centre already separated is much easier to handle.
Processing is generally performed for one of two reasons: Equipment is normally needed only to move material from one processing station to another or from processing to storage. It can be used to place recovered materials newsprint, cardboard, plastic, and aluminium in large agglomerations which can be easily moved and are stackable.
Since paper, cardboard, and plastic bottles can comprise a high percentage of a municipal waste stream, most recycling operations will need a baler to process this material. Baler types should be carefully investigated.
Operations providing bulk newsprint to paper recycling markets may choose a baler which makes bales of approximately 1, pounds each. On the other hand, a centre selling shredded newsprint for animal bedding to local farmers will need a hay baler, which makes small 70 pound bales.
For maximum flexibility, perhaps both types of balers should be utilised, if sufficient space is available. The question of what type of baler will be best for an operation is just one example of the need to do some homework before getting started.
Other processing equipment may be needed to satisfy downloader specifications and provide sufficient compaction to allow for cost-effective transport. A centre may use shredders, shears, grinders, and crushers. Each piece performs a different function but all have the objective of reducing waste volume.
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For example, there are a variety of shredders available, which will shred paper, cans and even automobiles. Glass crushers reduce bottles into a mixture called cullet, which is the form most attractive to glass recycling markets.
Solid waste is an abrasive and caustic material, which makes proper maintenance of waste processing equipment very important. Moreover, operating this equipment can be dangerous; special training and safety precautions may be required. Power needs can also be high. Consequently, processing's potential benefits must be carefully weighed against its cost and operational considerations. Recycling centres may not require drive-on scales, if volumes received are small or the need to move and process material quickly is not great.
Note that a recycling centre operated in conjunction with a landfill or transfer station might be able to use the disposal facility's scale. Where manual sorting is used, a conveyer system, often coupled with a magnet to collect ferrous, provides a good way to move material from the tipping floor to other processing stations. After processing, material is often stored in large cardboard boxes, known as "gaylords," or in other similar containers.
download of backup transport equipment should also be seriously considered. The inability to move material from processing to storage caused by a lack of backups could create a serious disruption in the recycling operation. In designing a recycling centre, sufficient aisle room is a must. Designers must allow for easy and efficient movement of transport devices. A convenient loading dock, readily accessible to large trucks, is important; it should provide protection from inclement weather.
Material storage areas must be located close to the loading dock. Employee facilities and an office for record keeping and centre operations should also be carefully planned. Local building codes likely will mandate these and other features of the recycling centre. Improper past disposal practices have caused environmental degradation, need for costly remedial actions, and public opposition to the siting of new facilities.
In some areas of the country, waste is being hauled hundreds of kilometres as communities search for disposal options. For example in California, the Napa Valley wastes are transferred by rail across three states to the landfill disposal site, a distance of km. Until recently, managing waste was primarily a local matter.
Now, both the federal and state governments are beginning to impose stricter regulations on design and operation of facilities that manage or dispose waste. Protecting the public from the potential environmental and health impacts of poor waste management practices has become a national mandate.
Improved technology for collecting, processing, and disposing waste is being demanded by the public. Unless the future proves that our society can manage waste better than in the past, public opposition will continue to grow, costs will continue to rise, and the call for tighter and tighter restrictions will grow louder. At the heart of the debate is the landfill. Because old landfills were developed more to provide cheap disposal alternatives than to protect the environment, many have leaked.
But newer landfills are designed to contain waste products and to protect the environment over the long term.
Although other methods of managing waste, including recycling, composting, and incineration, are being instituted by communities around the country, access to a landfill remains a necessity for everyone. With the emphasis on waste minimisation and full cost recovery of waste management, along with more rigorous environmental requirements many communities around the country will face for the first time the need to construct state-of-the-art landfills. This course will describe the basic principles involved in developing and operating a state-of-the-art landfill.
In a landfill, solid wastes are disposed of by spreading in thin layers, compacting to smallest practical volume, and covering each day, or periodically, with soil or suitable substitute material in a way that minimises environmental problems. A landfill's design life extends many years beyond the time when it is closed. Waste stabilisation begins shortly after it is placed in the landfill, but will not be completed until years after closure. Care must be exercised to ensure that an environmental problem does not develop during operation or after closure.
Careful design, construction, and operation can minimise the potential for problems arising at a landfill. Recently, many questions have been raised about the long-term impacts associated with land filling. Site selection and approval has proven very difficult due to neighbour and political concerns. Questions regarding the eventual disposition of the landfill materials had resulted in renewed interest in decomposition processes and biodegradability.
These special topics will be addressed later. In the trench method the excavation into which the landfill is placed is excavated specifically for the purpose of land filling. The soil is temporarily stockpiled.
The waste is placed on the ground surface or, more commonly, a landfill liner, spread in layers, and driven over with compaction equipment. Successive layers are built up until a depth of 3 to 4 m is achieved see Figure The cover material my be soil or a synthetic material and is usually placed at the end of each day's operation, or more frequently.
Possible exceptions to this procedure are when limited equipment availability at small sites results in less frequent covering, or when a large site operator continuously fills the area, in which case cover may not be required.
A completely covered compacted solid waste unit is called a cell. A cell's width depends on the number of vehicles unloading solid waste at a given time. The width of the working face can be increased to accommodate vehicles unloading side by side. However, if the working face is too wide, nuisance conditions may develop.
A good practice is to keep the working face as small as possible. A series of adjoining cells, all the same height, makes up a lift. The completed fill consists of several vertical lifts which may extend 20 to 50 m above the original ground surface.
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The final cover for the landfill will be about 1 m of soil or a combination of soil and synthetic materials. The function of the final cover is to limit the entry of water into the landfill. This results in reduced letéléchargemente generation, that is, the release of contaminated liquids from the base of the waste in the landfill. Limiting the entry of water, however, greatly slows decomposition; thereby extending the time period before the waste is finally stabilised and environmental monitoring of the site can cease.
The area method is shown in Figure This is used when the terrain or soil conditions are such that cells or trenches cannot be dug.
Site preparation can include the use of liners and letéléchargemente control systems. Figure The Area Method of Landfill The canyon method is similar to the trench method except natural depressions or canyons are used rather than digging trenches. It depends upon the area covered, the depth of the waste, and the ratio of waste to soil or synthetic cover. The air space within the landfill is the volume available into which solid waste and cover may be placed.
The tonnage of solid waste which can be land filled in a given air space will increase as the quantity of soil cover is reduced by better construction practices or the substitution of synthetic materials and the compaction of the solid waste is increased. Waste-to-soil ratios of 4: Probably the biggest advantage of sanitary landfills, when compared to open dumps, is the protection of public health and the environment.
The major objections to sanitary landfills are initial costs for design and construction, public opposition when siting, and increasingly, the concern for recovery of material instead of disposal.
Example 3. A community of 50, people uses a 12 hectare landfill site that can be filled to an average depth of 20 m. If MSW is generated at a rate of 2. Due to less than ideal conditions in a landfill, the observed gas yields are about cubic metres per tonnes of waste. Other 'bulk' components of landfill gas those gases measured at percentage levels include hydrogen, oxygen and nitrogen.
The relative proportion of these gases, together with key trace components often falls within a range that is characteristic of gases from different sources, and can help to identify the source of migrating gas. Table shows some typical values of landfill gas composition as well as some recorded maximum levels.
Heiss-Ziegler and Leachner, Both methane and hydrogen are flammable in the presence of oxygen and are therefore potentially explosive if ignition occurs within a confined environment. The exact values for the upper explosive limit U. L and lower explosive limit L. Methane is non-toxic, but through displacement of oxygen within the root-zone, may cause death of surface vegetation.
Where landfill gas migration has occurred, the migration pathway can often be followed by visual observation of the surface vegetation, including trees, which show withering at leaf margins, defoliation, and branch dieback. In extreme cases, surface heating of the soils can also be detected.
Whether these surface-heating effects are a result of heat transference from the warm gas or a consequence of biological methane oxidation is not clear. In the latter case, the methane oxidising bacteria utilise the methane for bacterial growth, releasing carbon dioxide as an end product and some consideration has been given to the use of such bacteria in landfill gas control systems. Carbon dioxide is an asphyxiate by virtue of oxygen displacement, and can cause deaths due to paralysis of the respiratory centres.
The threshold limit value for CO2 is 0. Oxygen and nitrogen are usually present in landfill gas due to mixing with atmospheric air. Nitrogen is essentially inert and will have little affect except to modify the explosive range for methane, and although oxygen deprivation will result at the levels normally found in landfill gas Table it is difficult to envisage a situation where anyone would find themselves in an environment of 'pure' landfill gas.
In many cases the level of oxygen within a gas collection system is used to monitor abstraction rates, and to control the rate of pumping.
In addition to the hazards associated with the major 'bulk' gases the minor trace components may also exert a deleterious impact upon the environment and upon human health. Many of the trace compounds in landfill gas are recognised toxicants when present in air at concentrations which exceed recognised toxicity threshold limit values TLV's or the Occupational Exposure Standards OESs set by the Health and Safety Executive.
Anyone coming into contact with landfill gas is therefore potentially at risk from the toxic nature of the minor components. For gas migration to occur there must either be a concentration gradient to allow diffusion in the gaseous phase diffusive flow , a pressure gradient viscous flow or a combination of both.
Gas diffusion is the process by which matter is transported from one part of a system to another as a result of random molecular movement, and the rate of gas diffusion is inversely proportional to the square root of its density. Thus a 'light' gas such as methane will migrate 1. The method of filling is the most important factor affecting within site gas migration. Thin layer techniques utilising good compaction and dally cover will tend to encourage lateral gas migration, especially where the cover materials are of low permeability.
Conversely, the construction of wells within the site will tend to favour vertical gas migration within and around these structures.
During landfill development, any gas produced will vent via the pathway of least resistance. Therefore prior to final capping and assuming that only permeable intermediate cover has been used, most gas produced will vent to atmosphere. However, after final capping, gas venting to the atmosphere will be limited according to the effectiveness of the cap. As a result, gas pressure will develop within the landfill creating a driving force for gas migration.
Under these conditions, the possibility of the lateral migration of gas increases and the rate and extent of migration will depend upon a number of factors including environmental, climatic and geophysical conditions. Environmental factors are essentially restricted to conditions within the waste and will affect the rate and extent of waste degradation and hence affect the rate and extent of landfill gas pressure build up.
Geophysical conditions will affect the gas migration pathways; faulted and fractured strata and strata of varying gas permeability will affect the direction and rate of gas movement and can be modified by hydro-geological factors such as water table levels. Gas may travel large distances through such strata and once at the 'surface' may enter surface structures resulting in a potentially explosive situation.
At sites lacking gas control measures, landfill gas has migrated to metres beyond the site and indicates that there is no safe distance from a landfill site. The gas may migrate through permeable strata, caves and cavities, fissures, mineshafts, sewers, drains, tunnels, and other features that create a path of least resistance to gas movement. Climatic conditions including atmospheric pressure and rainfall can also affect landfill gas migration; as atmospheric pressure falls, the surface pressures opposing gas migration decrease thus facilitating gas movement.
The pressure differential between the landfill gas and atmospheric pressure is therefore important, and an inverse relationship a between atmospheric pressure and gas migration measured as methane concentration at off-site monitoring points can be demonstrated at a number of landfill sites.
Rainfall can affect gas migration through its effects on surface sealing, by causing surface materials to swell and close surface cracks, thus reducing vertical migration pathways with a resultant increase in lateral gas migration. Water infiltration can also increase water table levels outside the landfill and letéléchargemente levels within the site, thus reducing the gas volume and increasing gas pressure. Estimate the theoretical total volume of gas of STP that will be generated in a sanitary landfill by anaerobic digestion of kg of MSW, given that the waste can be represented by the chemical formula C70 H O45 N.
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If leakage does occur, an underlying groundwater aquifer may be contaminated. The extent of contamination will depend upon the permeability of the soil formation. Leakage into a porous formation may result in a large area being contaminated.
In the past, many landfills were not lined. Due to groundwater protection concerns, liners are being installed at the base of most new landfills to control and collect the letéléchargemente. Some inorganic materials will still be solubilised into the letéléchargemente by decomposition occurring during the second stage, so the fall in conductivity will not be as drastic as the fall in COD. After the readily degradable organic material has been broken down, methane production will decrease and more aerobic conditions may be established by incoming oxygenated water.
Actual landfills may vary considerably in the rates at which decomposition occurs. For example, the aerobic pH may last a few weeks or months with significant methane generation occurring within one to two years. Additionally, a single landfill may have different parts in different stages of decomposition, with the gas and letéléchargemente composition reflecting the three stages. Second stage decomposition takes several years or perhaps decades to complete.
Landfill letéléchargemente is comprised of the soluble components of waste and the soluble intermediates and products of waste degradation which enter water as it percolates through the waste body. The typical analysis of landfill letéléchargemente is shown in Table Heiss-Ziegler and Leachner, The amount of letéléchargemente generated is dependent upon a number of factors such as water availability, landfill surface conditions, refuse state and conditions in surrounding strata.
With regard to public health and environmental protection, a properly designed and operated landfill will offer advantages in the following areas: Making the site pleasing to look at, while largely cosmetic, is not frivolous. Aesthetics include screening of daily operations from roads or nearby residents by, planting, or other landscaping. They include an attractive entrance with good roads and easy-to-read signs. At the site, aesthetics means litter control, principally by the use of a fence to stop blowing paper and plastic, along with manual or mechanical pickup of the litter.
In addition, the site operator may require all trucks delivering waste to be covered with tarps. The NSW Guidelines state "Vehicles leaving it does not mention entering a landfill site must not distribute litter and site materials in surrounding streets.
Odours, dust, vermin, weeds and litter must be effectively controlled on-site" EPA, Even more important to the protection of public health and the environment than the steps described above is the control of gas generated by the decomposition of solid wastes; and of letéléchargemente formed as water migrates through the solid wastes, picking up a variety of biological and chemical contaminants.
Methods are available to control both gas and letéléchargemente, and will be discussed in detail in later.
These can be a nuisance or even cause problems with planes if the landfill is near an airport. In the USA, Federal Aviation Administration requirements prohibit the operation of a landfill within 10, feet of an airport and, under some circumstances, up to 5 miles. Several methods, including use of noise makers, and nets or wires suspended over the site, have been tried to discourage birds at landfills near airports.
Odours are best controlled by daily cover, as well as by adequate compaction. Daily cover also forms cells which are thought to reduce the ability of fires to spread throughout the landfill. Although the majority of these occurrence were associated with gas migration without serious incident. Drainage problems within the landfill maybe complicated by the presence of daily cover. The downward movement of water may be impeded by the intermediate soil layers and result in letéléchargemente seeping out of the side of the landfill.
It is recommended that daily cover be removed near the outer edges of the fill before subsequent lifts are added so that downward movement of water is facilitated. Flies and mosquitoes are best controlled by daily cover of the solid wastes along with the elimination of any open standing water. These can be a problem at open dumps, but the use of cover, insuring that all food wastes are buried, eliminates rat problems at a sanitary landfill.
While recycling may be desirable, the scavenging of material from a landfill is usually prohibited. Scavengers have been injured, sometimes fatally, while picking through the waste, and scavenging should not be allowed. To be more specific, waste is defined as a moveable object which has no direct use- unwanted material discarded permanently. This definition also refers to solid waste. Hazardous waste is a waste which include solids, sludge, liquids and containerized gases, except radioactive and infectious wastes, due to their chemical activity reactivity or toxicity, explosive, corrosive, or other characteristics, cause danger to health or environment, either it is stand alone or in contact with other wastes.
Hazardous wastes can be grouped into 2 categories; which are hazardous substance material which have some commercial value because they are usable and hazardous wastes material which had been used, spilled or no longer needed. For the classification of any material as a hazardous waste, the material itself must be considered as waste and meet one of the following criteria: It is usually produced during industrial, chemical and biological processes.
The household, office and commercial wastes also contain small quantities of toxic waste like batteries, old pesticides and containers. Since, it is can be in the variety of forms, it requires specific treatment. The followings are the general characteristics of toxic waste: Examples of toxic wastes: Also can be found in batteries and leaded gasoline.
Also found in medical applications such as in cancer therapy. The US government was the first to initiate legislation to regulate hazardous waste. Before that, the term hazardous waste was usually referred to special industrial waste or chemical waste. Beginning early s, hazardous waste became leading environmental issue to the society.
Along with the public concern on the toxic reaction, hazardous waste had dominated environmental issues. In Malaysia, the enforcement on the hazardous waste management only started in , with the introduction of the hazardous waste related act, i.
They pose enough threat to deserve regulation as hazardous waste. Examples of such wastes include solvents, paint wastes and gasoline. Wastes as follows are considered as ignitable: The followings are some examples of corrosive wastes: Here, waste is unstable and reacts violently without detonating, reacts violently with water that causes fire splash, forms explosive mixture with water, generates toxic gases when mix with water, contains cyanide or sulphide and pH lower or equal to 2 or pH of A set of regulations dealing with hazardous waste management which regulate the storage, transport, treatment and disposal of hazardous wastes was enforced on May is as follows: In the regulations, it is specified that before the disposal, the scheduled waste should be rendered innocuous and waste generated should be reduced.
There are categories of schedules wastes, which group into 2 parts: In November , a hazardous waste treatment plant for processing chemical waste was opened in Bukit Nanas.
This plant model was based on Danish hazardous waste processing plant, Kommunekemi, Nyborg. This is the first plant for processing hazardous waste in Malaysia. The owners of Kualiti Alam hold the contract for treatment of all hazardous waste in Peninsular Malaysia for 15 years.
When the plant was being designed, Malaysia drew up legislation on hazardous waste as an addition to the above legislation. It is known as Environmental Quality scheduled Wastes Regulation The plant receives all types of hazardous waste except hospital and radioactive waste. Organic waste is burnt in the incineration plant.
Acidic and basic inorganic fluids are exposed to chemical treatment that neutralizes them and removes poisons such as chromium and cyanide. The residues from this treatment and solid inorganic waste are bound tightly with lime and cement before being deposited on a double membrane equipped landfill with room for waste residues for up to 20 years.
Between , an average of , tonnes of scheduled waste was generated per annum, mainly from metal finishing, electronics, textile, chemical and chemical-related industries, agricultural and domestic activities, and clinical waste from hospitals. Companies generating wastes are now required to inform the authorities about hazardous waste and whether there is a need for associated collection, storage and processing.
In addition, the companies have to pay for this service on the basis of the polluter pays principle. Ability to describe basic concept of air pollution and solve basic calculations in this area. Generally, air pollution occurs when there are impurities in the atmosphere that can cause bad effects or harm to the human health, animals, vegetations and materials. Below are some definitions taken from a number of sources: Air pollution is the presence in the outdoor atmosphere of one or more air contaminants i.
Rapid industrialisation, development and greater dependence on fossil fuels have contributed to the increment of harmful pollutants, making life more unpleasant and unhealthy. Air pollution disaster had been reported as early as in London but for the moment three major episodes will be discussed. In each of these cases, a persistent 3 -6 days inversion combined with significant industrial or, in London, domestic pollutant emissions resulted in high ground-level concentrations that caused acute illness.
In each case, the death is caused by existing respiratory cardiovascular disease. For London disaster, pneumonia was the primary cause of death. Table describes briefly the characterization of these episodes. Davis and Cornwell, The unhealthy air quality recorded in other parts of the country was mainly due to high levels of PM In , Malaysia experienced short periods of slight-to- moderate air pollution in the months of June, August, and September.
This was mainly due to south westerly winds that caused the deterioration of air quality in the west coast of Peninsular Malaysia. The fires in Kalimantan also contributed to the slight haze in the southern part of Sarawak. Apart from these haze episodes, there were no other serious incidences of air pollution in Particulate Matter PM and ground-level O3 remained the prevailing pollutants in the country.
The air quality status, based on APIs, in major Malaysian cities for are shown in Figures through DoE, Figure Source: Natural pollutants such as dust storms, forest fires and volcanoes may pose serious air quality problems when they are generated in significant quantities near human settlements.
However, natural air pollution has not been a major societal concern. Anthropogenic man-made air pollution such as mobile sources has been and continues to be a serious problem.
Its seriousness lies in the levels of pollutant produced in environments that harms human health and welfare. There are three main contributors to air pollution load in Malaysia reported for They are stationary sources, mobile sources and open burning sources.
Table indicates the distribution of industrial air pollution sources by states for From the table, Selangor contributes the highest number of stationary sources that is Figure shows the recent estimates of emissions in Malaysia. Mobile sources such as passenger cars, taxis, buses, motorcycles, vans and lorries are the main contributors to air pollution. Figure shows the distribution of air pollution emission load from mobile sources for From the figures, DoE, Figure Distribution of air pollution emission load in percentage from mobile sources, 2.
It was enacted in The main environmental regulatory agency in Malaysia at the federal level is the Department of Environment or DoE, which is currently part of the Ministry of Natural Resources and the Environment. Environmental management is conducted at the federal level by the DoE and headed by the Director-General of Environmental Quality, who is appointed by the Minister from among members of the public service.
Within each state, the state governments have corresponding authorities and officials in charge of environmental matters. Primary pollutants e. Secondary pollutant e. For examples, hydrocarbons are organic compounds containing only hydrogen and carbon while ketones and aldehydes contain oxygen, carbon and hydrogen. Particulate pollutants consist of finely divided solids and liquids including dust, fumes, smoke, fly ash, mist and spray. The particulates pollutants will settle out under proper condition.
Gaseous pollutant is the formless fluids that completely occupy the space, into which they are released, behave more like air and do not settle out. Gaseous pollutants include vapours of substances that are liquid or solid at normal temperatures and pressures. Particles can be classified from their mode of formation as dust, smoke, fumes, fly ash, mist, or spray.
Figure shows the characteristics of particles and particle dispersoids. Below are the classifications of particles according to their formation: The size range from 1.
The size range from 0. Fumes are from sublimation, distillation, calcination or molten metal processes. Spray liquid particles formed by atomization of parent liquids e. Settleable particulates are washed out with rain or settles down as dry depositions and they are usually measured by dustfall bucket. Suspended particulates are usually measured by high volume sampler or portable mini volume sampler. It is a basic and inexpensive device consists of an open bucket containing water to trap and holds the particles.
It is exposed at suitable location such as building roof for 30 days. After 30 days of collection, the water is evaporated and the particulates are weighed. The inlets are designed to remove the larger particles before the sample reaches the filter. The filter is weighed before and after sampling, and the airflow rate, which gradually decreases as particulates accumulate on the filter, is accurately metered and recorded. For the ease of monitoring in site, portable mini volume sampler is designed so that it can be placed easily at the desired monitoring site.
Figure and shows the high volume sampler and portable mini volume sampler respectively. Micrograms per cubic meter and parts per million are a unit of measurement for concentration and they are used to indicate the concentration of gaseous pollutant. Formerly concentration of gaseous pollutants were usually reported in parts per million ppm , parts per hundred million pphm , or parts per billion ppb by volume. Determining the volume, temperature and pressure relationship.
Calculate the volume occupied by 4 mol of gas at To solve this problem, first of all, volume of NO2 need to be find. For that purpose, equation  will be used.
The major organs of RS are the nose, pharynx, larynx, trachea, bronchi and lungs. The nose, pharynx, larynx and trachea are called upper respiratory tract URT. The lower respiratory tract LRT consists of bronchi and lung which is composed of alveoli. These are: An asthma attack is the result of the narrowing of bronchioles. The small grape-like cluster become a large nonresilient ballon-like structure and the amount of surface area for gas exchange is reduced drastically.
The growth closes off the bronchioles and usually cause fatal. The formation of carboxyhemoglobin COHb effectively deprives the body of O2. At COHb levels of 2. The average concentration of CO inhaled in cigarette smoke is ppm. Asbestos, arsenic, benzene, coke oven emissions and radionuclides are carcinogen or cancer causing.
Berylium causes lung disease and also affects the liver, spleen, kidneys and lymph glands. Mercury attacks the brain, kidneys and bowels. It is inhaled and ingested in food and water. Early symptom of Pb poisoining is a mild anemia deficiency of red blood cells.
Chronic exposure to Pb may result in brain damage charecterized by seizures, mental incompetence, highly active aggressive behavior, weakness of extensor muscles on hands and feet or eventual paralysis. Atmosperic Pb occur as particle. The size range 0. At a lower concentration, it gives brownish yellow tint. Exposure to NO2 concentration above 5 ppm for 15 minutes will cause cough and irritation of respiratory tract. At 5 ppm NO2 has a pungent sweetish odor. The average NO2 concentration in tobacco smoke is approximately 5 ppm.
At a concentration of 0. Concentration above 0. Some investigations have pointed out that particles less than 2. Figure shows a cross section through the mature leaf consisting of 3 primary tissue systems: The opening in the underside of the leaf is called stoma plural of stoma is stomata. The mesophyll includes the palisade parenchyma and spongy parenchyma containing chloroplast that is the food center. The guard cells regulate the passage of gases and water vapour in and out of the leaf.
Ozone O3 injured the palisade cell. The chloroplast condenses and the cell walls collapse resulting in the formation of red-brown spots and white spots fleck. O3 injury occurs during midday on sunny days. The guard cells are more likely to be open and thus allow the pollutants to enter to the leaf. Nitrogen dioxide NO2 and sulfur dioxide SO2 can inhibit the growth of the plant at a low concentration and produce necrosis at higher concentration surface spotting due to loss of protoplasm or known as plasmolysis.
The reduction in surface area leaf results in less growth and small fruit. Fluoride deposition on plants will damage them. Grazing animals may accumulate an excess of flouride that mottles their teeth and causes them to fall out.
A small amount of UV gives you the summer tan skin but too much of the UV will cause skin cancer. Oxygen also absorbs the UV but only over a narrow band centred at a wavelength 0f 0. The photochemistry of these reactions is shown in figure The M refers to any third body usually N2.
Ozone in upper atmosphere is when oxygen reacts with the light energy hv: When the CFCs are introduced into the upper atmosphere, ozone is destroyed.
Figure shows ozone destruction by chlorofluorocarbons. First, the CFCs react with light energy to release chlorine atom. One form of CFC reacts as follows: Accelerating ozone-layer depletion will have serious impacts on most of living things on earth. This radiation can cause the change in genetic structure, alters the immune systems, damages crops, disrupts the marine food web, enhances greenhouse effect by affecting the carbon dioxide absorbing capacity of plankton in oceans and increases the incidence of skin cancer.
Figure shows how the increased UV-B radiation and change in climate caused by depleted ozone will affect life on earth. Environmental reduced crop effects: Crop and yields, forest damage stunted plant growth Aquatic: Increase Increases lower fish harvest in infectious incidence of diseases, less cataracts and effective vaccination blindness Human health effects: Khan, In October , a working group of the Montreal Protocol on Substances that deplete the Ozone Layer established four 4 review panels to implement Article 6 of the protocol.
They covered the scientific, environmental, technical and economic aspects of ozone layer depletion. The main conclusions reached by the panels were published and distributed in by the United Nations Environment Programme UNEP , which acts a secretariat to the protocol.
At least one year assessment, the Parties shall convene appropriate panels of experts qualified in the fields mentioned and determine the composition and terms of reference of any such panels. Within one year of being convened, the panel shall reports their conclusions, through the Secretariat, to the Parties Article 6, Montreal Protocol Source: Khan, In the spring of , eighty countries met at Helsinki, Finland to access the new information.
Phase out production and consumption of ozone-depleting CFCs no later than Phase out production and consumption as soon as feasible of halons and such chemicals as carbon tetrachloride and methyl chloroform that also contribute to ozone depletion. Commit themselves to accelerated development of environmentally acceptable alternative chemicals and technologies.
Make relevant scientific information, research results, and training available to developing countries. The implementation of the Montreal Protocol appears to be working. This is because of the carbon dioxide in atmosphere reacts with the rain water by these reactions: Atmospheric substances from volcanic eruptions, forest fires and other similar natural phenomena also contribute to the natural sources of acidity in rain but not acidic enough to destroy plants and animals.
Acid rain has been associated with sulphur oxides SOx ; principally sulphur dioxides SO2 and to a lesser extent, sulphur trioxide SO3 and nitrogen oxides NOx principally nitrogen oxide NO and nitrogen dioxide NO2 combining with oxygen to form sulphur dioxide and nitrogen oxides. These gases react with water to form sulphuric and nitric acids which are soluble and fall with the rain.
Acid rain major sources are from human sources, such as industrial and power generating plants, transportation vehicles and farming industries ammonia for fertilizer. The gases can be carried hundred of miles in the atmosphere before they are converted to acids and deposited. Industrial acid rain is a major problem in China, Eastern Europe, Russia and areas down winded from them. These areas also burn coal containing sulphur to generate heat and electricity.
In the gas phase sulphur dioxide is oxidized by reaction with hydroxyl radical via a tri- molecular reaction: Lower pH values may affect fish directly by interfering with their reproductive cycles or by releasing otherwise insoluble aluminium Al , which is toxic. At pH lower than 5, most fish eggs will not hatch and lower pH can kill adult fish.
As lakes become more acidic biodiversity is reduced. Acid rain also leaches calcium Ca and magnesium Mg from the soil thus lower the molar ratio of Ca to Al which in turn, favours the uptake of Al by fine roots that ultimately leads to their deterioration.
Acid rain can also damage certain building materials and historical monuments due to chemical reactions between sulphuric acid and calcium compounds in the stones limestone, sand stone, marble and granite to create gypsum that flakes off. The toxic released due to acid rain forms the greatest threat to human. In ,the US Congress authorized a 10 year study to assess the causes and effects of acidic deposition. In September, NAPAP released an interim report that indicated that acidic precipitation appeared to have no measurable and consistent effects on crops, tree seedlings, or human health, and that a small percentage of lakes across the US were experiencing pH value lower than 5.
In , NAPAP reported to Congress that there remained no evidence of widespread decline of forest tree species causes by acidic deposition.
Earth atmophere can be divided into four major layers refer Figure The temperature decreases with altitude. Pollutant that migrate into this layer can stay for many years. This layer has a high ozone concentration. Air pollution problem occurs in the troposhere.
Pollutants in the troposphere whether produced naturally or emitted from human activities are moved by air currents that we call wind.
Wind not only moves the pollutants horizontally, but causes the pollutants to disperse, reducing the concentration of the pollutants a distance away from the source. Lapse rate is the change of air temperature with height. It is used as indicator as the stability condition of the atmosphere. There are 3 stability categories that are: The lapse rate for a neutral atmosphere is defined by the rate of temperature increase or decrease experienced by the parcel of air that expands or contracts adiabatically without addition or loss of heat as it raised through the atmosphere.
Mathematically, atmospheric stability can be determined as: Air stability determines whether clouds form when air is uplifted, and the type of cloud. Whether or not this air packet continues to rise will depend upon how the temperature in the surrounding air changes with altitude.In Malaysia, the enforcement on the hazardous waste management only started in , with the introduction of the hazardous waste related act, i.
Fluoride deposition on plants will damage them. Storage indoors of newspaper and other items can create problems for a poorly designed centre, as there can be a constant struggle between space needed for processing and operations and space requirements for materials storage. The A weighting network is the most important network. Therefore prior to final capping and assuming that only permeable intermediate cover has been used, most gas produced will vent to atmosphere.
Early symptom of Pb poisoining is a mild anemia deficiency of red blood cells. Air pollution is the presence in the outdoor atmosphere of one or more air contaminants i.
Thus a 'light' gas such as methane will migrate 1. It is recommended that daily cover be removed near the outer edges of the fill before subsequent lifts are added so that downward movement of water is facilitated.