The History Of Construction Waste Minimization Environmental Sciences Essay

The History Of Construction Waste Minimization Environmental Sciences Essay Chapter two is a review of contemporary literature related to the topic. It will explain how authors perceive Construction waste recycling method for waste minimization purposes. The literature review will also discuss about the underpinning theory, what is known and unknown about the topic. It will also discuss about what various researchers have done in the past, especially in the area of construction waste recycling method for waste minimization purposes. 2.2 BACKGROUND Much of the waste stream going to landfill consists of solid waste from the construction and demolition of buildings. Waste minimisation strategies have been popular for some time in the construction industry. This paper considers the effect of these strategies on one case study. Sourcing materials with recycled content in terms of embodied energy and cost is suggested as the next phase of environmental management in construction. Many studies measure waste from construction sites on the basis of either volume or mass, to gauge the effect on disposal costs (Johnston and Minks, 1995; Graham and Smithers, 1996; Faniran and Caban, 1998). This does not give the best appreciation of the problem in terms of the environment. The savings from using materials with recycled content can be best measured in terms of the environment by considering their embodied energy (Thormark, 2000). Embodied energy represents 10-40 times the annual operational energy of most Australian residential buildings, depending upon building design, climate construction systems, equipment type, fuel sources and building usage patterns. Each year in Australia, the embodied energy used in construction is approximately equal to the annual operational energy of the built stock, and together they make up 30-40 per cent of national energy use and greenhouse gas emissions. There are several problems with existing embodied energy analysis methods, which include process analysis, input-output analysis and hybrid analysis. Process analysis, while accurate for particular processes, often ignores a large number of small to medium processes. Input-output analysis, despite its many inherent errors, is used because of its unique property of systemic completeness. Errors for process analysis data are approximately 10 per cent (Boustead and Hancock, 1979), and for input-output data errors are approximately 50 per cent (Miller and Blair, 1985). Hybrid analysis methods attempt to reduce the errors inherent in each of the two previous methods. There are two types: one based on the process analysis framework and the other based on the input-output framework. For the hybrid analysis methods, errors vary between these rates, depending upon the mix of process and input-output data. 2.3 Construction Waste Construction waste can be divided into three principal categories namely material, labour, and machinery waste. However, material wastage is given more concern because most of the raw materials used in construction industry come from non-renewable resources (Ekanayake and Offori, 2000). construction waste is defined as: the difference between the value of those materials delivered and accepted on site and those used properly as specified and accurately measured in the work, after deducting the cost saving of substituted materials and those transferred elsewhere (Peng and Tan, 1998). Similarly, the Building Research Establishment (BRE) has defined building waste as the difference between materials ordered and those placed for fixing on building projects (Skoyles and Skoyles, 1987). Recently, for the purpose of evaluation of the construction material waste sources, Ekanayake and Offori (2000) have given a broader definition of the construction waste as: any material, apart from earth materials, which need to be transported elsewhere from the construction site or used within the construction site itself for the purpose of land filling, incineration, recycling, reusing or composting, other than the intended specific purpose of the project due to material damage, excess, non-use, or non-compliance with the specifications or being a by-product of the construction process. 2.3.1 Definition of construction waste Construction waste is anything generated as a result of construction and then abandoned, regardless of whether it has been processed or stockpiled. It comprises surplus materials from site clearance, excavation, construction, refurbishment, renovation, demolition and road works. There are two types of construction waste: Inert construction waste Non-inert construction waste Non-inert construction waste is around 20% of the total and usually comprises bamboo, timber, vegetation, packaging waste and other organic materials. Some of these can be recycled while others are disposed of at landfills. In contrast, inert waste otherwise known as public fill mainly includes construction debris, rubble, earth, bitumen and concrete, which can be used for land formation. Materials like concrete and asphalt can also be recovered for construction use. Wastes can be defined as all wastes in solid form which are discarded as useless or unwanted and in general arise from human activities. Construction wastes are wastes generated from building, demolition and refurbishment works for individual housing, commercial building or other structures. (Peavy et al., 1985) 2.4 Construction waste minimization Waste minimization is a waste management approach that focuses on reducing the amount and toxicity of hazardous waste that is generated. In addition to hazardous wasted regulated under RCRA, the EPA encourages waste minimization techniques that focus on preventing waste from ever being created, (source reduction) and recycling. there are three general methods of waste minimization: source reduction, recycling, and treatment. 2.4.1 Steps of waste minimization: Reduce consumption of resources by building smaller houses that are better designed for your needs. This is the most effective way to conserve precious resources for use by future generations and reduce waste. It also lowers costs. Re-use existing buildings and materials and reduce demand for resources, lower waste volumes and save money. Dont Demolish Deconstruct, give old buildings new lives. Recycle resources that are left over or have reached the end of their useful life. This will reduce demand for new materials and lower the volume of waste going to landfill. sending building material to landfill is like throwing money in the bin. Use renewable resources like sustainably managed forests. This creates a sustainable economy and helps conserve non-renewable resources use materials with high recycled content to create a market for recycled resources. It will raise the price paid by recyclers for recovered resources and increase the viability of recycling. 2.4.2 Landfill Our traditional means of waste disposal (landfill) is uneconomic. Costs to communities for operating and maintaining landfill sites are high and availability of suitable land is limited. Re-use options for landfill sites are extremely limited due to potential health hazards. Remedial action is often prohibitively expensive. Emissions and leachate from landfill sites can be highly toxic due to concentrations of heavy metals and toxic chemicals. These toxins find their way into the water table and/or waterways, often with disastrous consequences. We must reduce waste volumes going to landfill and remove toxic content from materials before disposal. Using other option then sending to landfill. . 2.4.3 Why prevent waste and recycle? 2.4.3.1 Reduce Costs Recycling, reusing salvaged building materials and minimizing materials and packaging reduces waste disposal costs and material expenses. 2.4.3.2 Marketing Opportunity The companyà ¢Ã¢â€š ¬Ã¢â€ž ¢s experience in waste prevention and recycling can be an essential marketing Tool to the growing number of potential clients interested in participating in the Leed and Build green building programs. 2.4.3.3 Tax Deduction When you hire a deconstruction service to remove reusable building materials, the client can Take a tax deduction when they donate the materials to a nonprofit organization. 2.5 Construction Waste Management Construction Waste Management is the practice of reducing the actual waste that go to the dump site. Waste reduction is best met by recycling and construction wastes do offer a lot of opportunities for recycling. In fact, 80% of the wastes found in construction trash heaps are recyclable, one way or another. Wood, asphalt, concrete, bricks, metals, glass and even paint do offer several options for recycling.There are three basic steps for construction waste management. They are Reduce, Reuse, and Recycle. Reduce is basically preventing waste from appearing. So it helps if those building materials come in with preplanned sizes. 2.5.1 Construction waste management strategies Four main construction waste management strategies were identified from the literature (Gavilan and Bernold, 1994; Peng et al., 1997; Faniran and Caban, 1998). They were: reuse; avoid or reduction; recycling; and disposal. Among these three strategies, avoiding waste which infers elimination or minimization of waste, has been given the highest priority as it requires the least resources other than planning and designing skills. Developing a waste minimization culture in the construction industry may be the initial process of a minimization strategy (Teo and Loosemore, 2001; McDonald and Smithers, 1998). Reuse refers to simply moving materials from one application to another. The third option is recycling and construction waste recycling is a process of separation and recycling of recoverable waste materials generated during construction and remodelling. Composting has also begun to emerge as a new application of an ancient technology, where organic land-clearing debris is processed to produce humus for soil treatment (Ekanayake, 2000). Further, incineration is another process of destroying waste material by burning it and, while once regarded as a practical method of disposing of hazardous waste materi als, it has of late, become controversial for many reasons such as the fact that it creates toxic gas and ash, which can harm local populations and pollute groundwater. Disposal or land filling is the lowest in the hierarchy. Since reduction was identified as the most effective strategy for waste management, several techniques used in construction can be recommended as waste reduction initiatives. Off-site construction technology (dry construction) was highlighted in the literature. For instance, using pre-cast elements one could eliminate 30 per cent to 40 per cent of wastage on building construction sites (Poon et al., 2004b). In addition, there are many advantages of pre-cast element manufacturing such as saving time and overall cost, due to enabling concurrent different production lines; increasing constructability and reducing congestion on site due to changing from an uncontrollable work environment on site to a controllable one in factories (Benjaoran and Dawood, 2004). Therefore, the present paper attempts to identify how effective the use of pre-cast elements in building projects are in construction to minimize construction waste. 2.5.2 Insufficient regulations The importance of complete governmental regulations for supporting construction and demolition waste management has been extensively investigated. For example, although the Hong Kong government has implemented various types of regulations to minimize construction and demolition waste production, it is found by Tam (2008a) that the mandatory system in implementing the waste management plan for all construction projects would significantly affect the productivity of companies. This is echoed by the study from Shen and Tam (2002), suggesting that legal measures are not effective for implementing environmental management in Hong Kong construction. In all the regulations in Bulgaria, construction and demolition waste is mentioned jointly with municipal waste and the majority of measures envisaged are aimed at the improvement of municipal waste management (Hadjieva-Zaharieva et al., 2003). It is also reported by Kartam et al. (2004) that clear regulations and rules from Kuwait Municipality are lacking for allowing and persuading contractors to use recycled products made from construction and demolition waste.

Chemistry 208 All QUIZ Essay

The Scientific Method Step 1: Performing Experiments Step 2: Making Observations Step 3: Proposing a Hypothesis Step 4: Confirming the Hypothesis Step 5: Proposing a Scientific Law Scientific Notation It is a mathematical expression in which a number is expressed as N x 10^n where N contains only one nonzero digit to the left of the decimal and n is an integer. Rules for Determining Significant Figures (digits) -All nonzero digits are significant figures -Counting begins from the left with the first nonzero number -Zeros between nonzero digits are counted as sig. Figures -Terminal zeros (zeros to the right of the right of a number) are always significant if the value contains a decimal point. Ex: 2. 3700 g: 5 significant figures 17. 50 mL: 4 significant figures Rule 1- In calculations involving measured values (with a certain # of sig. figs), the number of sig figs in the final answer depends on the operation performed. Rule 2- In multiplication and division of measured quantities, the final answer contains the same number of sig figs as are in the measurement with the least number of sig figs. Rule 3- In the final answer of a calculation involving exact numbers, unit conversion factors and constants, the number of significant figures is dictated by the measured quantity involved. Density = Mass/ Volume Matter: The term matter is used to describe things that occupy space and are perceivable by our senses. It can be classifies in terms of its physical state or chemical composition. Elements: composed of one type of atom. Classified as a metal, nonmetal or metalloid. Compound: a combination of elements in a definite proportion. Atoms of each individual elements are chemically combined to form the compound. A chemical change can break down a compound into its individual elements. Mixture: a non-pure substance made of 2 or more elements or compounds that can be separated by physical procedures. Protons have a positive charge, found in the nucleus. Neutrons have no charge, found in the nucleus. Electrons have a negative charge. The atomic number of an element is equal to the number of protons in the nucleus of its atoms. The mass number is equal to the number of protons and neutrons in the atom. To calculate the number of neutrons, subtract the atomic number from the mass number. Molecules are a combination of atoms in a definite proportion e. g. , molecule of water Ions are charged species formed by loss or gain of electron(s) from an atom. Loss of electron – cation (positively charged) Gain of electron – anion (negatively charged)

American Literature Essay

?American literature is any written work of art that is created in the United States. American literature is like all literature, it has literary experiences and contextual history of America. It depicts how America has changed is still changing today. American literature has changed over time just like most canons of literary works. The uniqueness of American literature is that America from its beginning had a special philosophy of life and freedom. The special philosophy of life and freedom that made American literature so unique was reflected in its writings. Americans believed and had faith that God was and is the given of all our rights and freedom. We as Americans had faith in ourselves that we could succeed in anything that we try doing. The literature that we Americans wrote made life worth living because it was displayed for the world to read and understand that life was what we made it. Also by Americans having the ability to spring back from diversity made life worth living and George Washington was a perfect example of this. Literary canon is basically a suggested list of readings that belongs to a country or a certain period in time. Literary canon contains literary works that is mainly by authors who are accepted as an authority in their field and their writings constituting a serious body of literature in any given language. The works that are collected that is included in a literary canon is approved largely by cultural and academic institutions and is observed as literature of that language. Literary work’s popularity is not based only on the quality, but on the relevance of what matters to the context historically, socially, and artistically. Literary canon relate very well to what is going on in society because of what is most important at that time work is being written. The context of the society, whether it is historical, social, or artistic, that is basically the topic. Ethnic writers express the special challenges of realism, naturalism, and regionalism within the American literary experiences. Realism labels a movement in English, European, and American literature that gathered force from the 1930s to the end of the century. Realism attempted to record life as it was lived rather than life as it ought to be lived or had been lived in times past. William Dean Howells stated that realism â€Å"is nothing more and nothing less than the truthful treatment of material. † Present-day literary theorists are probably more aware of what may be called â€Å"the crisis of representation†-the difference between representation and the thing represented-than were these realists of the late nineteenth and early twentieth century. Naturalism is understood by some as an extension or intensification of realism. It introduces characters from the fringes and depths of society whose fates are determined by degenerate heredity, a sordid environment, and/or a good deal of bad luck. Regionalism writing, another expression of the realist impulse, resulted from the desire both to preserve a record of distinctive ways of life before industrialization dispersed or homogenized them and to come to terms with the harsh realities that seemed to be replacing these early and allegedly happier times. By the end of the twentieth century, every region of the country had a â€Å"local colorist† to immortalize its natural, social, and linguistic features. Ethnic writers define literature as literature that is written by people of a different culture, language, religion, or race. It differs from the canon of traditional American literature because literary canon is a list of work from American instead of from a different race or religion. The historical, socio-political, and cultural topics that might be covered by ethnic writers would be slavery and how the slaves were treated during that time. Slavery is a topic that can be covered under all three. Government issues are a topic that could be covered under socio-political. The debate against government issues such as health care and taxes could be something that ethnic writers could write about. It does not differ from the canon of traditional American literature because the writings have to be by authors who are accepted as an authority in their field and their writings of literature in any given language.

Cave Hyena Facts and Figures

Name: Cave Hyena; also known as Crocuta crocuta spelaea Habitat: Plains of Eurasia Historical Period: Pleistocene-Modern (2 million-10,000 years ago) Size and Weight: About five feet long and 200-250 pounds Diet: Meat Distinguishing Characteristics: Long hind legs; strong jaws with sharp teeth About the Cave Hyena (Crocuta crocuta spelaea) Its not quite as well known as the Cave Bear or the Cave Lion, but the Cave Hyena (Crocuta crocuta spelaea) must have been a common sight in Pleistocene Europe and Asia, to judge by this megafauna mammals numerous fossil remains. As you can guess from its name, this hyena liked to drag its kill (or, more often, the kill of other predators) back to its den, for which purpose it was equipped with longer, more muscular hind legs than contemporary hyenas (of which the Cave Hyena is now classified as a subspecies, rather than a separate species as had previously been thought). One network of caves in Europe has yielded tantalizing evidence about the Cave Hyenas favorite prey animals, with Przewalskis Horse and the Woolly Rhino ranking high up on the dinner menu. Like most opportunistic predators of the Pleistocene epoch, Cave Hyenas occasionally preyed on early humans and hominids, and they werent shy about stealing the hard-earned kill of packs of Neanderthals (which might well doom them to starvation). Where Crocuta crocuta spelaea and the ancestors of modern humans really mixed it up was in the competition for habitable space: paleontologists have identified caves that bear evidence of alternating populations of Cave Hyenas and Neanderthals, a pattern that evidently repeated itself over thousands of years. In fact, the Cave Hyena may have been doomed by the encroachment of early humans on its rapidly dwindling caves, which grew even scarcer after the last Ice Age, about 12,000 years ago. Like many other animals with which our ancestors shared their hard-won territory, the Cave Hyena has been immortalized in primitive cave paintings. One cartoon-like representation can be found in the Chauvet Cave in France, dating to about 20,000 years ago, and a small sculpture (carved from the ivory of a Woolly Mammoth!) was created a few thousand years after that. Its likely that both early humans and Neanderthals memorialized the Cave Hyena as a kind of demigod, and also painted it on the walls of their caves in order to capture its essence and facilitate success in the hunt. (Its unlikely that early Homo sapiens targeted the Cave Hyena for its stringy meat, but its pelt would have been valuable in winter, and anyway it was a good idea to eliminate the competition!).