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.
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: to place the material in the most economical form for transport, or to meet buyer specifications. 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 buyer 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. 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. Purchase 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. 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 leachate 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 leachate 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 are common. 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. 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. 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 leachate levels within the site, thus reducing the gas volume and increasing gas pressure. Example 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.
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 leachate. Some inorganic materials will still be solubilised into the leachate 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 leachate composition reflecting the three stages. Second stage decomposition takes several years or perhaps decades to complete. Landfill leachate 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 leachate is shown in Table With regard to public health and environmental protection, a properly designed and operated landfill will offer advantages in the following areas: aesthetics, especially litter; decomposition gases and leachate; birds; fires and odours pests; rats; and injury from scavenging. 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, Methods are available to control both gas and leachate, and will be discussed in detail in later.
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.
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 leachate 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. 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. US EPA under subtitle C declared that waste is considered as hazardous if: i Waste is declared hazardous by its generators ii Material exhibit following characteristics; ignitable, corrosive, reactive or toxic.
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: i Show any characteristics of hazardous waste.
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. Examples of toxic wastes: i polychlorinated biphenyls PCB — non-flammable insulting material used by big electrical network.
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.
The followings are some examples of corrosive wastes: i An aqueous material which has pH lower or equal to 2 or pH 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: i Environmental Quality Scheduled Wastes Regulations 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: i Part 1 — Schedule Wastes from non specific sources, i. 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. 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. 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 Source: DoE, Figure Source: DoE, 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, 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. 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. Example Determining the volume, temperature and pressure relationship.
Calculate the volume occupied by 4 mol of gas at Solution: 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: i Bronchial asthma — form of airway resistance that results from allergy. 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 epidermis, the mesophyll and the vascular bundle veins.
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. When the CFCs are introduced into the upper atmosphere, ozone is destroyed. Figure shows ozone destruction by chlorofluorocarbons. The estimated amount of time this product will be on the market is based on a number of factors, including faculty input to instructional design and the prior revision cycle and updates to academic research-which typically results in a revision cycle ranging from every two to four years for this product.
Pricing subject to change at any time. Mackenzie L. Davis, Ph. He received all his degrees from the University of Illinois. From to he served as a Captain in the U. Army Medical Service Corps. During his military service he conducted air pollution surveys at Army ammunition plants. Army Construction Engineering Research Laboratory. His responsibilities included supervision of research on air, noise, and water pollution control and solid waste management for Army facilities.
In , he joined the faculty at Michigan State University. He has taught and conducted research in the areas of air pollution control and hazardous waste management.
In , he received the Lyman A. Melting ice Given: 2 kg of ice, W electric heater Solution: a. The specific heat of water from Table is 4. The temperatures in K are: Qriver T — From Eqn. This is an energy balance of the form of Eqn. Because of the differential this problem must be solved stepwise rather than in one 7 day stage b. The energy balance diagram is Energy in. Note that the lagoon is completely mixed and the temperature of the lagoon is the same as the temperature of the wastewater leaving the lagoon d.
Solving for T T. Heating a pump house Given: Dimensions 2m X 3 m X 2. This is an application of Eqn Begin by computing the surface area of the pump house. For wood walls H 1 2 0. For glass-wool H 1 2 0. Note: Solve in two steps. Then calculate the time to release all the enthalpy of fusion. Area of lagoon m 3 m 2 3m d. Enthalpy change due to aerator mixing A. Time to freeze 1,,,kJ 86, The efficiency is of the form W 2.
Limestone rock dissolving Given: limestone rock at bottom of Lake Michigan is dissolving Solution: The system is at steady state. Benzene in a pond Given: can of benzene has spilled into a small pond. What data are required to calculate the concentration of benzene in the water leaving the pond. Solution: The approach to answer this question is to write a mass-balance equation for the system and use it to identify the data required for solution. In simplified terms, assume steady state and no sorption to the bottom of the pond.
The mass that flows downstream may be estimated from the concentration and the flow rate of the stream.
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