INTRODUCTION TO ENVIRONMENTAL ENGINEERING BOOK
CHAPTER 1 INTRODUCTION TO ENVIRONMENTAL ENGINEERING 1 OBJECTIVES The followings are the objectives of this chapter: 9 Ability to describe. Editorial Reviews. About the Author. October No school address or affiliation. Highlight, take notes, and search in the book; In this edition, page numbers are just like the physical edition; Create digital flashcards instantly; Use X-Ray to. myavr.info: Introduction to Environmental Engineering (): Mackenzie L Davis: Books.
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Ordered the international version because why pay $ when you can get the exact same book in black and white for $ This book is the exact same as the. Building on the first principles of environmental chemistry, engineering, and ecology, this volume fills the need for an advanced textbook. Introduction to Environmental Engineering book. Read 7 reviews from the world's largest community for readers. Introduction to Environmental Engineering.
The atmosphere , a mixture of gases extending outward from the surface of the earth, evolved from the elements of the earth that were gasified during its formation and metamorphosis.
The hydrosphere consists of oceans, lakes, streams, and shallow groundwater bodies that interflow with surface water.
The lithosphere is the soil mantle that wraps the core of the earth. The biosphere, a thin shell that encapsulates the earth, is made of the atmosphere and lithosphere adjacent to the surface of the earth, together with the hydrosphere. It is within the biosphere that the life forms of earth, including humans, live. It brings along a need for more food, fuel, water, and goods and services. As such, it is vital to discuss on the interaction of the aspects of demographic and environment.
Population growth means more demand for good lifestyle. Above all, it creates a requirement for more investment to be committed to meet all these needs.
Consequently there bounds to be a rise in economic activities, a direct impact on a lot more people, and an increasing burden on the ecosystem. However, this should not be a case for an argument to be made against population growth.
If the environmental, economic and social carrying capacities of the system can cope with the demands, then it will be well and good. It must be emphasised that the purpose of an economy is to provide sufficient supplies of goods and services for the people and not to create more problems.
However, there is one vital caveat: In moving towards an era in which environmental stability is a prime factor in economic and social survival, similar observations with the earlier transition from the agricultural age to that of the industrial one can be inferred. That transition became possible only when agricultural production was sufficient to support not only those living on the agricultural land, but also the new industrial population.
Take one example: An ecologically satisfactory solution may be pursued in three ways: If the first route is emphasised then this may well imply that we should move away from our present technologically oriented society and go for a simpler lifestyle. The problem is that it would have to be much simpler, and at a population density far lower and not to resort to draconian measures.
It would also entail a very long period of adaptation. If the second route is chosen as the main solution, then policy makers must be fully committed to the cause. To deal with problems of waste through the wider application of technology, we will need large capital investments. In order to create this we will, in turn, need a level of industrial output that exceeds both consumption and economic requirements so that there will be enough money available for the investment in the necessary technologies.
The snag here is that the higher the levels of industrial output required, the higher will be the generated waste. Thus we have the twin feedback loops to address in every system: Therefore, these are the concerns of those involved in demographic questions. Taking Malaysia as a case in point, her per capita generation rate of solid waste has been reported to be around 0. This generation rate of solid waste is rather alarming. Serious effort should be made to overcome or to prevent this generation rate so that it will not exceed the capacity available to treat it.
An integrated approach should be taken in the decision making process and local authorities will have to gear up their plans to deal with the associated problems as they arise. In Johor Bahru for example, the population was rapidly increasing and subsequently posing a serious problem, like the piles and piles of solid wastes that are deposited.
As a possible impact, the population within this region will increase rapidly, and so will the amount of waste generation. It was not until approximately years ago that a concrete proof of disease transmission through water was established. In Malaysia for example a few rivers have been identified as highly polluted. Examples are Sungai Skudai and Sungai Juru. Assessments have shown that the impact of industrial area was the main contribution factor to this problem.
So, in this regard, it is going to be a tough time for environmental engineers to ensure the attainment of sustainable development. For many years, the major consideration was to produce adequate supplies that were hygienically safe. However, the water sources have become increasingly polluted due to the increased industrial and agriculture activities.
Pesticides used in agriculture pose the main threat to water sources. The public has been more precise in the demand for clean and healthy water as time passes by. As such environmental engineers are expected to produce acceptable treated water and maintain cleaner water resources.
In water science for example, the management of groundwater is very important compared to others like precipitation.
Environmental engineers will have to ensure that groundwater sources are free from pollutants. In Bangladesh for example, their sources of groundwater were heavily contaminated by arsenic. Therefore we have to look at and ensure the management system of groundwater sources is properly carried out.
Today, water engineers are expected to produce treated waters that are free of colour, turbidity, taste, odour, nitrate, harmful metal ions, and a wide variety of organic chemicals such as pesticides and chlorinated solvents. At present, more than 85 scheduled chemicals are listed in the U.
Health problems associated with some of these chemicals include cancer, birth defects, central nervous system disorders, disruption of the endocrine system and heart disease. As population increases, the demand for water also increases at a much more rapid rate if the unchecked population growth is accompanied by improved living standards. Thus the combination of these factors is placing greater and greater stress on finding adequate sources of clean and healthy water.
It is expected that this condition will continue and grow more complicated as the population and industrial development keep on growing. With the development of urban areas, it has become necessary, from the aspects of public health and aesthetic considerations, to provide drainage or sewer systems to transport such wastes away from these areas.
The normal repository was usually the nearest watercourse. It soon became apparent that rivers and other receiving bodies of water have a limited ability to handle waste materials without creating nuisance. This led to the development of purification or treatment facilities where chemists, biologists, and engineers have played important roles.
Water quality managers are concerned with the controlling of pollution arising from human activities to ensure that water produced is suitable for its intended uses.
Water quality management is crucial in handling water supply to the community. It is very important to know what level of waste is intolerable for a particular water body. To know how much waste can be tolerated by a water body, water quality managers must understand the type of pollutants discharged and the manner in which they affect water quality.
Therefore a good knowledge on good water quality sources like the ones found in Sungai Kejor in Belum, Perak and Sungai Sedim Kulim, Kedah is important. Originally, the intent of water quality management was to protect the intended uses of a water body while using water as an economic means of waste disposal within the constraints of its assimilative capacity.
Water is a natural resource and plays a significant role in human civilization. It has been long known that all natural bodies of water have the ability to oxidize organic matters without the resulting nuisance conditions, provided that the organic and nitrogen primarily ammonia loading are kept within the limits of the oxygen resources of the water.
It is also known that certain levels of dissolved oxygen must be maintained at all times if certain forms of aquatic life are to be preserved. Many research works have been conducted to establish these limits. Such works require the combined efforts of biologists, chemists, and engineers to realise their values. Apart of that, they have to develop effective technologies to meet the demand of sustainable treatment techniques.
The great variety of wastes produced from the industries and the introduction of wastes from new processes demand the knowledge of chemistry on the part of environmental engineers to find solutions to most of these problems. The problems associated with managing hazardous wastes are particularly complex.
Over millions tonnes of hazardous wastes are generated each year in the United States. The U. S Environmental Protection Agency has placed well over sites that are contaminated with hazardous chemicals on the National Priority or superfund list because of their potential threat to human health and the environment.
The Sungai Gatom case is a good example where hazardous wastes had been treated in an improper manner. Aluminium dros which are very harmful had been dumped illegally in this river and that posed a serious danger to public health. As a result the government had to fork out RM1.
However, the vehicles on the road keep on increasing, worsening situation further. The intensity of most air pollution problems is usually related to the amount of particulate matter emitted into the atmosphere. In general, visible particulate matter can be controlled by enforcing relevant regulations.
However the present regulations should be standardised to international standards as they lack certain aspects to meet the demand of current solutions to this environmental problem.
These regulations must be updated if they are to be more relevant to the present environmental conditions. The most serious situation develops when local conditions favour atmospheric inversions and the products of combustion and of industrial processing that are contained within a confined air mass. In cases where atmospheric inversions occur over metropolitan areas under cloudless skies, haze commonly called smog is produced in the atmosphere.
Under such conditions the atmosphere is often highly irritating to the eyes and to the respiratory tract and is far too intense to be accounted for by the materials emitted to the atmosphere from the varying and separate sources. Research on this field has been extensive. Many theories are postulated with regard to this problem, but the consensus is that it is the photochemical action between oxides of nitrogen and unsaturated hydrocarbons from automobile exhaust gases combined with several products of health concern such as ozone, formaldehyde, and organic compounds of nitrogen that give rise to the condition.
Introduction to Environmental Engineering , Third Edition
These substances can condense on particulate matter in the atmosphere to form fog. Knowledge of chemistry helps very much in finding the root cause of this matter. Motor vehicles, factories, and power plants are the main contributors to air pollution.
Such pollutants can cause cancer or other serious health effects, such as reproductive or birth defects, damage to the immune system, and respiratory problems, or they may cause adverse effects to the environment itself. The Clean Air amendments list toxic air pollutants that the U. S Environmental Protection Agency is required to regulate. These include particulate matter; halogen compounds such as tetrachloroethene, dichloromethane, and dioxin; heavy metals such as mercury, cadmium, and lead; volatile organic compounds such as benzene and toluene; and other hazardous compounds such as asbestos.
Building materials and furnishings are likely to include toxic chemicals that may be slowly released. Asbestos and radon, products used for household cleaning and maintenance, personal care, or hobbies often contain volatile can also cause serious harm. Usually the impact of human activities significantly cause problem in environmental quality.
Apparently, the human activities in one region have a significant impact and affected the quality of air at a much further region. This was true in the case of the radioactive fallout. Current concerns are on global warming and stratospheric ozone depletion. It is very important to grasp well the chemical principles involved to help us understand how these problems arise and how they could be solved. Because of this impact, chlorofluorocarbons are being banned from use globally and as such, replacement compounds are being sought.
This reaction led to the phenomenon known as greenhouse gases. Since they do trap heat trying to escape from the earth, they have potential for warming the earth, a process sometimes called global warming. Although there is a consensus on the reasons for increase on the concentrations of these gases, there is still an argument as to whether this will lead to a general increase in temperature.
Much remains to be learned here, and the expanding knowledge on environmental engineering will enhance and contribute to a better understanding of this problem.
It comprises legal matters on air, water, land and their impact on the environment. Aspect and impact factors are very important and play a vital role in protecting our environment.
It must be realised that human activities will somehow impinge on the surroundings. Activities in factories for instance, are directly associated with the pollution of the environment. Factories producing paints discharge a lot of toxic substances and they will have to be dealt with properly to avoid the resultant negative impact to surroundings.
Understanding of aspect and impact factors is a must for environmental engineers to meet the demand of sustainable development. As a result, we need clear guidelines to be closely followed in order to make sure our activities do not breach the existing laws and regulations. The Environmental Quality Act allows the Ministry of Natural Resources and Environment after consultation with the Environmental Quality Council to define objectionable noise and to prescribe standards for tolerable noise.
However, regulations with numerical limits of permissible noise are currently not available. Approval of such EIA and the projects usually include maximum permissible noise limits at the affected areas that must be complied with during the construction phase of a project, and upon operations of the projects plants, highway, etc. EIA also requires us to measure the existing environment before a project starts. These include water quality, air quality, and the existing land condition.
Therefore Environmental Quality Act is very important to be referred to before the development can commence. Legal compliance is very important when we implement a particular project and apply for certification. On chemical disposal for instance, there are clear guidelines on how to manage toxic wastes based on the relevant regulations. Industrial areas located near to water intake points must be strictly considered in accordance to the law and should comply with Standard A set out in the EQA Those factories situated away from water intake points must comply with the stipulated Standard B.
This is a clear message requiring us to control our water bodies based on the specified law and regulations. This act enables us to regulate open burning that gives rise to a serious problem in the form of haze to the environment.
The most important thing that one has to understand is that open burning activities are prohibited by the law. Environmental Quality Scheduled Wastes Regulations, Environmental Quality Clean Air Regulations, International Tropical Timber Agreement, , Geneva. Ability to describe the basic concept of noise pollution and solve basic calculations relating to it. Ability to describe the related legislation on Environmental Quality Act Many of us are exposed to high levels of noise while at work, travelling, shopping, and where there can be intrusive noise from traffic, domestic appliances, and especially if you are living in badly constructed apartments or terraced homes, from your neighbours.
In general, noise can be defined as unwanted signals. To be more specific, noise is defined as unwanted sound.
Therefore, noise can be considered as wrong sound at a wrong place and at a wrong time. Some people may find it tolerable, while others might find it annoying.
Involuntary noise is noise that can be avoided. An example of involuntary noise is noise produced in a crowded area like a packed stadium. Voluntary noise is the noise which can be tolerated and the sufferer is normally being compensated. For example, those who work at an airport have to tolerate aircraft noise. As such they are usually compensated with higher wages. In industrialized countries, noise is increasingly an environmental nuisance.
It can interfere with human communication and sleep. Noise can also reduce the value of properties, e. Noise can also result in both physiological and psychological effects.
Extremely loud and sudden noises cause pain to the ears and may cause temporary deafness or permanent damage to our hearing. High noise level of sufficient duration can result in temporary or permanent loss of hearing.
Prolonged exposure to noises which are not extremely loud can also affect hearing to a certain extent. Dangerous levels of noise come from industrial activities. Environmental noise intrusions such as traffic noise can interfere with communications, sleep disturbance and interfere with the ability to perform complex tasks. If the noise starts to spread out from air, it is called air-borne.
If the sound starts from vibration between structures, it is caused structure-borne.
The structure-borne noise occurs when building elements are in direct contact with the noise source. Sound waves are characterized by their frequencies, amplitudes and phases. The quality of a sound is determined by its frequency. For people with good hearing, the audible range of frequencies is normally between 20 Hz and 20, Hz.
In most practical noise control problems, however, it is possible to consider a rather narrower range of frequency, say 50 Hz to 10, Hz. Sound with frequency less than 20 Hz is called infrasound and sound over 20, Hz is called ultrasound.
However, most sound are not pure sinusoidal waves. They vary both in frequency and amplitude over time. To quantify their magnitude over the measured time T, the r.
Power, W, radiated by any acoustic source can be written as: For a point source, the noise is non-directional, and can be assumed as a spherical sound source.
For a spherical sound source, the sound intensities at all points on the imaginary sphere surface are equal. The acoustic intensity at a distance r m from the acoustic centre of a spherical sound source is: The maximum sound intensities at all points on an imaginary cylindrical surface sound source, is given by as: In an environment in which there are no reflecting surface, the r.
Therefore, sound pressure of linear scale is an inconvenient way to represent these quantities is to use logarithmic scale. An appropriate reference quantity is required. As sound level is expressed in logarithm scale, they cannot be added directly. For quick estimation, table or figure can be used for addition of sound level.
The Leq is a single value rating which has the same energy content as the varying sound level. As an example, sound pressure level cannot be used as an indication of loudness because the frequency of sound has quite a bit to do with how loud is the sound. For this reason, it is important for us to know the frequency of the noise we are measuring.
This contributes to the weighting networks. Weighting networks are electronic filtering circuit built into the meter to attenuate certain frequencies. They permit the sound level meter to respond more to some frequencies than to, something prejudicial like that of the human ear. The main different between these 3 networks are a very low frequencies are filtered quite severely by the A network, moderately by the B network, and hardly at all by the C network.
Therefore, if the measured sound level of a noise is much higher on C weighting than on A weighting, much of the noise is probably of low frequency. When the weighting network is used, the sound level meter electronically subtracts or adds the number of the decibels shown on each frequency from or to the actual sound pressure level at that reading.
American National Standards Institute Example 2. What is the corresponding SPL in dB? Example 2. Addition of Sound Level Four sounds from different sources are to be combined to obtain a total sound pressure level SPL.
What is the total SPL. By using Table 2.
Introduction to Environmental Engineering
Calculation of Leq Consider the case where a noise level of 90 dBA exists for 10 minutes and it followed by a reduced noise level of 70 dBA for 30 minutes. What is the equivalent continuous equal energy level for the 40 minutes period? Assume 5 minute sampling interval. Calculation of Leq An employee in a timber mill uses a saw to cut timber into different length.
While the saw is idle, it produces a level of 90 dBA at his work position. When it cuts into timber, it produces a level of 95 dBA.
An exposure of 8 hours per day is assumed. It carries both the sound pressure level and frequency. This follows from the variation in sensitivity of the ear with frequency. For this reason, measurement of SPL in dB is not a very accurate measure of loudness. The ear is not equally sensitive to all frequencies. Sound entering the ear is continuously frequency-analyzed along the cochlear partition, acting as a number of narrow band filters.
The ear is most sensitive from Hz to Hz. The units used to label the equal- loudness are called phons. Since the ear is most sensitive to frequencies in the range 1 to 5 Hz, sound at these frequencies would be rate much louder than one at the same SPL at other frequencies. The A weighting network is the most important network.
The unit is dBA. However, the dBA is a single figure rating. It does not provide information on the frequency content of a noise source. Noise meters are classified as follows: It is recommended that type I instruments be used for industrial measurements and for environmental measurements involving legislation. A new IEC will replace the above standards.
One major change is the abolishment of Type 3 noise meter. Fluctuations in level are common and sometimes the variations can be quite large. To accommodate this phenomenon the sound level meter is provided with 2 types of responses: It is most suitable for workers that move between many different environments during the working day.
Introduction to Environmental Engineering
If D is greater than 1, the exposure has exceeded the permissible limit. In this respect, regulations with numerical limits of maximum permissible noise are currently not available. Whilst regulations with prescribes noise limits are not legally defined the Department of Environmental had issued guidelines on permissible noise limits in its course of enforcement of the Environmental Quality Act.
The noise limits that are often used are tabulated in Table 2.
Sustainable Development of Algal Biofuels in the United States
The guidelines for Siting and Zoning of Industries also give daytime and night time noise limits based on maximum sound levels according to the category of the industries. This requirement must be strictly adhered to at noise sensitive areas such as hospitals and schools.
Approval of such EIA and the projects usually include maximum permissible noise limits at the affected areas that must be complied with during construction phase of the projects and upon operations of the projects i. Noise limits similar to that tabulated in Table 2. There are provisions in the Environmental Quality Act for the control of sound propagated to the environment, affecting the community.
The Department of Environmental is currently preparing guidelines for environmental noise control. These guidelines could then be enforced under the Environmental Quality Act and would be used in Environmental Impact Assessments, by the local authorities, and for planning proposes. Noise measurement and assessment procedures are to be also included.
Ability to describe basic concept of solid and hazardous waste and solve basic calculations on this area. For example, there were sites in ancient Rome which were pits where carcasses, animals and humans, were dumped. Cities from the Bronze Age such as Troy were actually raised in levels as garbage became unbearable. Clay layers were spread over the garbage, just as in modern tips.
Scavenging was one of the first forms of recycling and "rag and bone men" such as Steptoe and Son were just recyclers. The idea of scavenging was so bad to society that in the City of London outlawed the practice which is now an important part of the waste management industry.
Historically, links between wastes and health have been another important catalyst for change. A study in the mid 19th century demonstrated a link between sewage disposal in the Thames River and the incidence of cholera epidemics. This was 30 years before the cholera bacteria were even identified.
Some of the earliest waste disposal schemes were established in order to escape the health problems associated with the industrial revolution including the development of garbage collection, street cleaning, and sewage collection schemes.
Another early waste treatment which moved from Europe to USA was to stew garbage and dead animals in large vats. This produced grease and 'residuum' which was a black gooey material. The grease was used for the manufacture of candles, soap, lubricants etc, and the 'residuum' was used as plant fertiliser.
The other wastes from this process were runoff into streams. This process was stopped in Europe in the 's but continued in the USA until the 's. Incinerators were developed in the s in England, and with the industrial development incinerator technology improved. Waste management in Malaysia displays an array of problems, including low collection coverage on average due to the inaccessibility by vehicles of some areas, irregular collection services, inadequate equipment used for waste collection, crude open dumping and burning without air and water pollution control, inadequate legal provisions and resources constraints.
These problems are caused by various factors which have an impact on the development of effective waste management systems in Malaysia. Institutional constraints are among these problems. Even though several agencies like the State Department of the Environment and municipal councils are involved in waste management, they often have no clear functions in relation to waste management and there is no single agency designated to coordinate their projects and activities.
The lack of coordination among the relevant agencies often results in duplication of efforts in waste management, wasting of resources, and un-sustainability of overall waste management programmes. In the developing countries, waste management is becoming an acute problem as urbanization and economic development increase leading to larger quantities of waste materials requiring management in these countries.
In Asia, the management of waste materials requires immediate attention especially in countries such as China, South Korea and Malaysia which have been categorized as emerging industrialized countries. In , the urban areas of Asia produced about , tons of municipal solid waste MSW or approximately 2.
In , this figure is estimated to increase up to 1. Table 3. Countries with low incomes have the lowest waste generation rates, averaging 0. High income countries such as Korea, Hong Kong, Singapore and Japan, tend to have higher waste generation in comparison to other countries.
In Hong Kong, the generation rate is among the highest due to intense construction and demolition within the municipality WB, The amounts of waste in Japan and Singapore are lower but that is also due to the fact that the data do not include all municipal waste generated within these countries.
The characteristics of MSW vary from one country to another and the solid wastes of rural towns in Asia are significantly different from those of large cities, having more organics but few plastics from packaging or food wastes UNEP, There are also varying legal definitions of waste leading to differences in what is considered to be waste. In general, waste is defined as any material which is unwanted by the holder and intentionally thrown away for disposal.
This does not exclude that certain wastes may eventually become resources valuable to others once they are removed from waste stream WB, Malaysia, with a population of 24 million, is facing an increase of the generation and accumulation of waste. This development is causing social, economic and environmental problems at a significant level.
Individuals, industries, municipals, state and federal governments are concerned because improper waste management leads to health problems for local communities. Moreover, poor visual appearance has negative impacts on official visits and tourism. These problems are particularly serious in areas where intensive urbanization and population concentration lead to an increase of solid wastes and to a decrease of available land suitable for disposal. World Bank. What a Waste: Solid Waste Management in Asia.
May Malaysia, like most of the developing countries, is facing an increase in the generation of waste and of accompanying problems with the disposal of this waste. Overall, the local communities generate 16, tons of domestic waste per day and the amounts per capita vary from 0. On average, waste generation is about 1 kg per capita per day GAIA, Waste is grouped into three different categories in respect of disposal —solid waste, medical waste and hazardous waste.
According to a study by E. Roundtable on Urban Solid Waste Management. Incinerators were redesigned to allow more efficient energy production. At the same time there was an increasing awareness of environmental problems with a consequent upsurge in environmentally friendly practices including waste minimisation, waste recycling, and control of hazardous waste discharges.
One view of waste management is shown in the Figure The problem with this diagram is that it does not include waste minimisation or risk assessment procedures. These impinge on all the processes shown.
This diagram also provides a framework for much of the material we will cover in Waste Technology. Tchobanoglous, This refers to an arrangement or ranking of waste management actions which can usually be carried out in the community. At its simplest level you are probably familiar with "Reduce Reuse Recycle" This is a ranking of actions - we should reduce the amount of wastes produced as the first option. The next option is to reuse what wastes are produced, e. The third option is to recycle material, e.
This is depicted in Figure For example Figure shows a waste management strategy or hierarchy in which there has been a change from lower technology landfill disposal to higher technology recycling etc. This has also led to an increase in waste minimisation. Tchobanoglous, There are other similar strategies. Source reduction ii. Recycling reuse and recycling wastes iii.
Treatment - destroying, detoxifying or neutralising wastes iv. Disposal - discharging wastes. Other schemes utilise the 3 R's; Reduce, Reuse, Recycle. It can be seen that there is some overlap in these ideas - some common features, but they are very sketchy plans.
When trying to plan waste management we are dealing with people, and planning any human activity is a complex process. That is why we need to have relevant legislation.
The term municipal solid waste MSW is often found in the literature. It generally implies all the wastes generated in a community with the exception of industrial process wastes and agricultural solid wastes.
Waste composition is used to describe the individual components that make up a solid waste stream and their relative distribution, usually based on percentage by weight. This is usually determined by a waste composition study. Waste composition is likely to change because of changes in lifestyle, increased recycling, education programmes, and changes in collection systems. Wastes are classified based on their composition.
The National Waste Database Classification scheme should be used to ensure a standard approach. It does not include food processing wastes from canneries, slaughterhouses etc. Garbage originates mostly from domestic kitchens, stores, markets, restaurants etc Rubbish consists of combustible and non-combustible solid wastes from homes, stores and institutions but does not include garbage. The term trash is often used in the same way but is probably more a subset of rubbish.
The combustibles consist of paper, rags, wood, tree branches etc. Residential and commercial solid wastes, excluding special and hazardous wastes, consist of organic and inorganic solid wastes from residential areas and commercial establishments.
Typically the organic wastes include food waste also known as garbage , paper, cardboard, plastics, textiles, wood, yard wastes etc. The inorganic fraction includes glass, metals - ferrous and non ferrous e.
If the waste components are mixed, then it's referred to as commingled MSW. Wastes that decompose fairly quickly, e. Non-industrial refineries, chemical plants, wastes including food wastes, power stations, demolition etc rubbish, ashes, demolition and construction wastes, special wastes, hazardous wastes Agricultural Crops, orchards, dairies, Spoiled food wastes, agricultural feedlots, piggeries, farms etc wastes, rubbish, hazardous wastes Source: If we know how much waste is generated, we can then design management strategies to handle reduce, reuse, recycle etc those wastes.
This sounds very good in principal, but the problem is we do not have very good figures on amounts of wastes being generated. The actual composition of the wastes generated is another problem of definition. Figure shows the composition of the Malaysia domestic waste stream. Hassan, There are also variations depending on the source of the wastes - residential versus commercial wastes.
For example, the recent waste audit in Muar showed that food wastes made up There are also variations over time as waste management has changed. Another important aspect of waste composition is the composition of recyclable material in MSW. Most of you are familiar with recyclable materials such as plastics, glass, metals etc. Substantial recycling is taking place in Malaysia which marks the future changes in waste composition. This requires some sort of classification system. Classification is usually into hazardous and non hazardous classes, but could be extended to include recyclable versus non recyclable.
Of the 12 tonnes of raw produce,10 tonnes become products,1. Stored separately, the damaged cans are recycled. Assume the materials separated for recycling and disposals are collected daily. Prepare a material balance for the cannery on this day and a material flow diagram accounting for all of the materials. Also determine the amount of waste per tonnes of product. Step 1: On the given day, the cannery receives the following: Step 2: As a result of internal activity: Step 3: Determine the amount of waste per tonne of product: These are important for the management of waste disposal and for the recovery of a range of materials, including energy.
It is important to note this information is distinctly important to determine the method of MSW disposal such as composting, landfills, recycling etc. The important physical properties of MSW include density sometimes referred to as specific weight , moisture content, particle size and distribution, field capacity, and porosity.
Density varies because of the large variety of waste constituents, the degree of compaction, the state of decomposition, and in landfills because of the amount of daily cover and the total depth of waste.
Inert wastes such as construction and demolition materials may have higher densities, and density can change as in landfills where the formation of landfill gas and decomposition may bring about significant mass loss. Density is important because it is needed to assess the total mass and volume of waste which must be managed.
The density of MSW is often referred to as loose, as found in containers, un-compacted, compacted etc. Density varies not only because of the type of treatment it gets collection vs. Some typical density values are presented in the Table Agumuthu, Moisture content is important in regards to density as above , compaction, the role moisture plays in decomposition processes, the flushing of inorganic components, and the use of MSW in incinerators.
Pre-treatment of waste to ensure uniform moisture content can be carried out prior to landfill disposal. The wet weight moisture content can be determined using the following equation: 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 leachate, and leachate 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 buy-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 buy-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 buy-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 buyers. 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.
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 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. To see what your friends thought of this book, please sign up. To ask other readers questions about Introduction to Environmental Engineering , please sign up.
Can I read it online? See 2 questions about Introduction to Environmental Engineering…. Lists with This Book. This book is not yet featured on Listopia. Community Reviews. Showing Rating details. More filters. Sort order. Jul 16, Sunny Koundal rated it it was amazing. This review has been hidden because it contains spoilers. To view it, click here. Nov 07, Husamhammad added it. Loved the book, hated my class and teacher. View 1 comment. Zach Newman rated it liked it Jan 10, Rexel Marie rated it it was amazing Oct 13, Mohammedelasim Ahmed rated it did not like it Feb 03, Dienfitri rated it it was ok Oct 20, Peter rated it it was amazing Oct 17, Victoria rated it really liked it Jan 05, J Fidel rated it it was amazing Apr 17, Si Joh rated it it was amazing Feb 28, Arjun rated it liked it Nov 14, Shahzaibjutt rated it it was amazing Mar 26, Dec 11, Simrat Shergill jeji is currently reading it.
Jennifer rated it it was amazing Jan 15, Jessica Theola rated it really liked it Sep 01, Kavisha rated it really liked it Sep 08, Naqibullah rated it it was amazing Jan 04, Prakash rated it did not like it May 08, Yudili rated it it was amazing Jan 13, Pantuvo Tsoke rated it really liked it Dec 17, Eliza rated it it was ok Sep 23, This refers to an arrangement or ranking of waste management actions which can usually be carried out in the community.
In designing a recycling centre, sufficient aisle room is a must. Begin by determining lapse rate: Ian rated it it was amazing Feb 08, If the noise starts to spread out from air, it is called air-borne. For a point source, the noise is non-directional, and can be assumed as a spherical sound source. Line III represent an isothermal lapse rate i.
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