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Environmental Studies The Hong Kong Polytechnic University Recommended Reference Books 1. Introduction to Environmental Engineering and Science , 2nd edition Author: Gilbert M. Masters Publisher: Prentice Hall 2. Introduction to Environmental Engineering , 3rd edition
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Recommended Reference Books 1.Introduction to Environmental Engineering and Science, 2nd edition Author: Gilbert M. Masters Publisher: Prentice Hall 2.Introduction to Environmental Engineering, 3rd edition Author: Davis, Cornwell Publisher: McGraw-Hill International 3. Environment Hong Kong
Environmental System 1. Definitions Environmentis the physical and biotic habitat which surrounds us; that we can see, hear, touch, smell and taste. Pollution can be defined as an undesirable change in the physical chemical, or biological characteristics of the air, water or land that can harmfully affect the health, survival or activities of humans or other living organisms.
Environmental System 2. Environmental systems Environmental systems can be classified into 3 categories: • Water resource management system • Air resource management system • Solid management system
Environmental System Water Resource Management System Water supply subsystem The nature of the water resource commonly determines the planning, design, and operation of the collection, purification, transmission, and distribution works. The 2 major sources used to supply community and industrial needs are referred to as: • Surface water i.e. stream, lakes and rivers
Environmental System • Groundwater i.e. water pumped from wells 3. Interaction of systems A number of different environmental problems are associated with water, air or land systems. Many of these problems will apply only within one of these systems, justifying the breakdown into these categories.
Environmental System Such a classification is also useful for easier comprehension of related problems within one system. Moreover, it is sensible because, for managerial and administrative reasons, such subfields as air pollution, water supply, wastewater disposal and solid waste disposal are often dealt with separately by governmental agencies. Unfortunately, many important environmental problems are not confined to an air, water or land system but involve interactions between systems.
Environmental System A current example is the acid rain problem stemming from the emission of sulfur dioxide and nitrogen oxide gases into the atmosphere from the emission of sulfur dioxide and nitrogen oxide gases into the atmosphere from the sacks of generating stations, smelters, and automobile exhausts. These gases are then transported by air current over wide regions. Rainfall “washes them out”, creating acid rain which is harmful to aquatic life, forest and agricultural crops.
Environmental System While many environmental problems are local or regional, others must be viewed from an overall water-air-land interaction standpoint on a national, continental, or global basis. A simple illustration of this interaction is shown in following figure and hips to explain how an insecticide like DDT is now ubiquitous. 4. Environmental problems Environmental problems are always interrelated . Sometimes a solution to one problem actually creates another problem.
Environmental System For example, when people are sick and dying from disease, it is natural to want to improve human health. The health is improved and infant mortality is reduced, a pollution explosion may results. To feed this growing pollution, natural habitats are often converted into farmland. In turn, the destruction of natural habitats eliminates the native wild plants, predatory animals, and parasites. But when natural predators and parasites are killed, outbreaks of insect pests become more common. When farmers use pesticides to control the pests and protect the crops, they also pollute the environments.
Environmental System The development of this entire cycle in itself consumes irreplaceable fossil fuel supplies and when fuel are burn, air pollutants are generated.
Environmental System To make the task a bit more manageable, we can divide environmental descriptions into 5 main types. (1) Overpopulation The human population has risen very rapidly in recent years. This increase has led people to ask whether the earth has become overpopulated. Overpopulation may be defined as the presence in a given area of more people than can be supported adequately by the resources available in that area.
Environmental System It is important first because overpopulation is major case of all other environmental problems. Fewer people would need less food, chop down fewer trees, burn less oil, and discharge less sewage into rivers. Second, remedies for overpopulation and the starvation that accompanies it are generally higher on our list of priorities than other environmental concerns.
Environmental System (2) Pollution Pollution is a reduction in the quality of the environment by the introduction of impurities. There are 2 distinctly different types of pollution. A. Concentration of natural wastes Before modern civilization, most organic wastes did not accumulate in the environment, because they were dispersed sufficiently so that decay organisms could consume and recycle them.
Environmental System Thus, the quality of the environment was not impaired. In modern times, the organic wastes are often produced in such a concentrated manner that natural decomposition cannot clean the environment rapidly enough. For example, a city may house several million people in a small area of land.
Environmental System Organic wastes from such a city are not spread evenly about the countryside but instead are concentrated in a few locations sewage that is dumped into a river decays naturally but the process takes time. If the volume or the concentration of sewage is high, the water may not become purified by the time it reaches the next site downstream where pure drinking water is needed.
Environmental System Natural wastes can be inorganic as well as organic. Inorganic wastes would include compounds of elements such as lead, cadmium and arsenic. These elements exist naturally in the soil and rock all around us and are also present in small concentration in our bodies. As a trace elements, some are harmless, and many are even essential to bodily functions. However, even moderate doses of most inorganic compounds are poisonous.
Environmental System Such substances are often concentrated during mining and smelting operations. B. Introduction of synthetic chemicals into the environment People have recently learned to make new chemical compounds, called synthetic chemicals. In 1985, 70,000 different synthetic chemicals were produced in quantity for common use and about 2000 new compounds have been entering the environment every year since then.
Environmental System They are present in paints, dyes, food additives, drugs, pesticides, fertilisers, fire retardants, building materials, clothes, cleaning supplies, cosmetics, plastics and so on. Some of the synthetic chemicals are drugs that save millions of lives every year and other are poisons. But because most of them are new to the environment, the traditional patterns of decay and recycling do not necessarily apply.
Environmental System A material that decomposes in the environment as a result of biological action is said to be biodegradable. Most natural organic wastes are biodegradable many synthetic chemicals are not. For example, plastics remain in the environment for a long time because organisms that feed on them and bread them down are rare. Plastic shampoo bottles may produce unsightly litter, but they are not biologically active.
Environmental System However, many other chemical compounds not only are persistent but also are poisonous. Therefore, represent a significant threat to the environment. (3) Depletion of resources Resources of fuels, minerals, water, soil, and timber can be depleted or used up as it becomes less available for its intended function. Materials can become depleted in three different ways.
Environmental System 1) A substance can be destroyed, that is converted into somethings else. Fuels are destroyed when they are used. Coal is converted to ashes and gas. Uranium is converted to radioactive waste products. The ashes or waste products are no longer fuels.
Environmental System 2) A substance can be lost by being diluted, by being displaced to some location from which it cannot easily be recovered. If you open a helium-filled balloon, the gas escapes to the atmosphere. Not only atom of helium is destroyed, but the gas is lost because it would be impossible, as practical matter, to recover it.
Environmental System 3) A substance can be rendered unfit for use by being polluted. In this way, pollution and depletion are related each other. If industrial or agricultural wastes are discharged into a stream or if they percolate down through soil and porous rock to reach a supply of groundwater, these water resources become less fit for drinking or in the case of the stream, for recreation or for the support of aquatic life.
Environmental System (4) Changes in the global condition a.Climate Over the past 150 years or so a more instant in geological time-humans have significantly altered the chemistry of our environment. Today many scientists believe that these changes might affect the life support systems of the earth.
Environmental System For example, when fossil fuels are burned, carbon dioxide is released. In turn, the excess atmosphere carbon dioxide could possibly cause a general warming of the entire earth. Deforestation could affect global rates of photosynthesis and the composition of the atmosphere. Aerosol sprays and aircraft exhaust may be destroying the ozone layer in the atmosphere that filters out ultraviolet radiation.
Environmental System b. Extinction of species Throughout mush of the world, forests, shrublands and other natural systems are being converted to farmland. When habitats are destroyed, many organisms cannot survive. Therefore, hundreds of thousands of species of plants and animals are faced with extinction. People often do not know precisely what has been convinced that endangered species of plants or animals should be saved to preserve the genetic diversity of our planet.
Environmental System Some of these species are especially important, because they may produce lifesaving drugs or may be essential in breeding valuable crops or domestic animals. (5) War In many wars, war is a combination of all environmental problems rather than a separated category. In modern times, war ad the preparation for war have led to pollution and depletion of resources far more extreme than any single peacetime activity.
Environmental System People are killed, cities and farms are ruined and forested regions are destroyed. But even in the absence of actual conflict, the cost of maintaining armaments and standing armies is enormous. Finally, the potential for a nuclear war places the global systems of the Earth, human civilization and even the human species itself at risk.
Environmental System In many jurisdictions, regulatory are now focused on the generation of pollutants rather than on the capture and disposal of pollutants. The primary objective is to prevent or reduce pollution at its source. If pollutants cannot be prevented or reduced, they should be reused or recycled in an environmentally acceptable manner.
Environmental System If pollutants cannot be prevented, reduced or recycled, then they should be controlled or treated to reduce their harmful effects on humans and the environment. Disposal of untreated pollutants should be used only as a last resort. The idea is to analyze the production, use and ultimate disposal of the product to avoid creating pollution.
Environmental System Wastewater disposal subsystem Safe disposal of all human wastes is necessary to protect the health of the individual, the family, and the community, and also to prevent the occurrence of certain nuisances. To accomplish satisfactory results, human wastes must be disposed of so that: • They will not contaminate any drinking water supply. • They will not give rise to a public health hazard by being accessible to insects, rodents, or other possible carriers that may come into contact with food or drinking water.
Environmental System • They will not give rise to public health hazard by being accessible to children. • They will not cause violation of laws or regulations governing water pollution or sewage disposal. • They will not pollute or contaminate the waters of any bathing beach, shellfish breeding ground, or stream used for public or domestic water-supply purposes, or for recreational purposes. • They will not give rise to a nuisance due to odour or unsightly appearance.
Environmental System Wastewater Management Subsystem. (Source:R.K. Linsley and J.B. Fanzini, Water Resources Engineering, New York: McGraw-Hill, 1979. Reprinted by permission.)
Environmental System Air Resource Management System Our air resource differs from our water resource in 2 important aspects. • The first is in regard to quantity. Whereas engineering structures are required to provide an adequate water supply. Air is delivered free of charge in whatever quantity we desire. • The second aspect is in regard to quality. Unlike water, which can be treated before we use it, it is impractical to go about with a gas mask on to treat impure air and with ear plugs in to keep out the noise.
Environmental System The balance of cost and benefit to obtain a desired quality of air is termed air resource management. Cost-benefit analyses can be problematic for at least 2 reasons. • The question of what is desired air quality. The basic objective is, of course, to protect the health and welfare of people. But how much air pollution can we stand: We know the tolerable varies from person and person.
Environmental System • The question of cost versus benefit. We know that we don‘t want to spend the entire Gross National Product to ensure that no individual’s health or welfare is impaired, but we do know that we want to spend some amount. Although the cost of control can be reasonably determined by standard engineering and economic means, the cost of pollution is still far from being quantitatively assessed.
Environmental System Solid Waste Management Generally, solid waste is considered a problem to be solved as cheaply as possible rather than a resource to be recovered. A simplified block diagram of a solid waste management system is shown in following figure.
Environmental System A simplified block diagram of a solid waste management system. (Source: G. Tchobanoglous, H. Theisen, and R. Eliassen, Solid Wastes, New York: McGraw-Hill, 1977. Reprinted by permission.)
Environmental System Environmental Awareness • Human activity affects the environment • Sustainable development - urban, industrial environmental consideration & awareness Environmental Protection depends on • Attitude - Government, Citizen, Industrialist
Environmental System Role of government in environmental protection 1. Environmental education in schools and colleges. 2.Public awareness promotion: informal teaching by publicity in media; drawing attention to health hazards and propagranda or programs to improve the environmental condition. 3.Release of information on affairs and policies of environmental concern, information on regulatory control, standards and enforcement procedures.
Environmental System 4.Education of the industrialists in providing guidelines, training, regulation information, self-esteemed motivation, and information on complaint procedures. 5.Provide incentive for pollution control practice for the polluters 6.Administrative control: good town and landuse planning, pollution control zone, frequent inspection on potential polluting industries, and enforcement of the pollution control legislation. 7.Legislation on pollution prevention, laws and ordinance on environmental protection. Government should show their own compliance on the regulations for government development projects as an example to industries.
Environmental System Role of environmental education in the enhancement of environmental protection 1. Government attitude on environmental education and its impact on secondary school students influences on the present and future attitude on environmental protection for the younger generation. 2. Tertiary and technical institute‘s environmental education programs and courses on the training of the technical and professional personnel for government and industrial sector on environment management and pollution control.
Environmental System 3. Environmental education on the public through government, mass media, broadcasters, press and their impact on the citizens and society. 4. Educaiton of the industrial sector through government persuasion, public awareness programs and mass media exposure and promotion of pollution control practice. 5. Education through social awareness programs and the promotion of environment friendly products.
Environmental System Public participation 1. District board: Industrial / Urban development 2. Environmental Protection COMmittee (EPCOM) • nominate prominent citizens, environmental group, industry, government departmental representative EPD • Advisory committee on environment-related policy matter 3. Environmental groups
Environmental System Public Participationare important as different interests in the development are balanced through • Familiarization of the project by the public • Problems identified: EIA (Environmental Impact Assessment) • Interest identified • Public review of the project • Conflicts resolved: sustainable development
Environmental System Public participation will ensure that all interests are balanced and the parties concerned will include environmental consideration in the planning, design, constructional and operational stages and that steps are taken to minimize the adverse impacts on the environment to the satisfaction of society.
