Factors Of Waste Generation Environmental Sciences Essay

As a development country, the economic keep on growing and a lot of construction project will be carry out. Since this construction project is kept on increases, it will face a major problem on waste management. It is no longer strange or new for the construction waste and pollution produced in the sites which affect the environment issue.

Reuse and recycling of construction waste is now a big recommendation for nowadays construction industry. There is a waste management which conducts a different management process in all over the world. Malaysia is using the “Site Waste Management Plan” to control the waste in our country. However, there are not much contractor follow the “Site Waste Management Plan” and just simply dump the construction wastes anywhere.

The aim of this study is to learn the ways of recycling and reuse of construction waste management in a construction. Basically this study focus on what type of waste recycle to be use, which construction waste can be recycle or cannot be recycle, and the successful demolition of waste and issue of waste. With the study of waste management in Malaysia, I can know how the contractor did the waste management and how much level of awareness about waste minimization by contractor.

1.2 Introduction

Construction waste is no longer a new issue or topic for a construction industry. Some waste is unavoidable even the design is perfect in a construction industry. Construction projects are required to make sure that it give impulse to the economy, improve the standard of living and provide opportunity for jobs. The overall construction industry make profit to the country however it is not an environmentally-friendly industry as it will cause air, water, noise and land pollution which all can be linked to the construction industry (Mohd Nizam Bin Yusoff, 2010).

It is to be said that the construction industry creates chances and injects money into a nation’s economy by giving an opportunity for foreign and local investment (M. Agung, 2009). However, despite these contributions, the construction industry has also been linked to global warming, environmental pollution and degradation (Jones & Greenwood, 2009). As we all know that not only construction can generates a huge amount of pollutants, including solid waste, noise, dust and water, other industries also will generate but in a small amount as compare to construction industries (Ball, 2002; Morledge & Jackson, 2001).

To start construction activities, construction cannot start if no any other direct influence industries. There are many direct influences on many other industries which define as both purchasing the inputs from other industries and providing products to almost all other industries, eliminating or reducing waste will produce a great amount of cost savings to society (Polat & Ballard, 2004).

Although Material Storage Management (MSM), the new concept for minimizing the waste in the construction industry is recognize, but contractor is not fully participate for this new concept. As the cost of labour is expensive than building materials cost, contractor rather allow construction material waste than put more human resources in managing the waste materials (Yau and Wong, 1997; Wong, 2000). Since foreign country are advance in controlling the construction waste strategies, Malaysia as a developer country should also consider about the problem occur in construction waste management.

Recycling of construction waste will help the communities to reach the goal by preserve valuable space in their local landfills (Schlauder and Brickner, 1993). Nowadays many reuse and recycle method for construction waste which will lead to minimization of construction waste. Contractors will have to participate on such recycle method to overcome construction waste management problems.

1.3 Problem Statement

Construction waste has affected the environmental problems especially for many large and developing cities. About 38% of the construction waste is generated from construction, which is among 6,408 tonnes of waste per annum are produced from construction activities. The amount wastes generate from construction industries is high as compare to other industry. This problem will affect the cost to expel the construction and demolition waste rising rapidly as it is becoming more and more expensive. The construction and demolition waste (C&D) is the most critical waste in the whole world.

According to Malaysia Environmental Quality Report 2005, the total quantity of wastes in a year is 548,916.11 metric tonnes. This is a huge amount of wastes that we need to be considered and find out a way to control this situation. As from the Malaysia Environment Quality Report 2005, the oil and hydrocarbon waste has the highest percentage 22.4 while phenol/ Adhesive/ Resin waste has the lowest percentage of 0.3. On the other hand, for the type of industry, electronic waste is the highest with percentage of 23.7 while printing and packaging waste is the lowest with percentage of 0.5.

Construction industry is a huge consumer of non-renewable resources and a massive producer of waste and the operation of the buildings are responsible for about half of the toal CO2 emissions (K. A. M. Kamar, Z. A. Hamid 2011).

Therefore, it is needed to find out the solution and way to conduct waste control to minimize the construction waste. This must be start from now on and being practice by all construction industry to avoid pollution of environment and reduce the construction waste.

1.4 Scope of Study

Construction waste management is too wide for carrying out a research as waste is classified into two types, waste of material and waste of manpower. In this situation, I will narrow down the scope of study for construction waste management in order to get my work done smoothly. In this case, I specify my scope of work by focusing on several aspects on construction waste management.

Main focus of my research is on the Kuala Lumpur construction company’s waste management practices in Malaysia. I will mainly focus on type of construction waste material which are metal and also concern about metal industry. This is because metal is considers as the middle waste produce in the construction industry and it is a common waste. Metal is always being used by construction industry and almost all the metal waste are not reuse or recycle in a proper ways.

Besides, I will also focus on how the contractor reuse, recycle and remove other construction waste material from site. As for different construction industry, they will practice different ways of settling the construction waste and this will be interesting to be known.

1.5 Aim and Objectives

Aims:

To study the ways of recycling and reuse of construction waste management in a construction.

Objectives:

2.2 To investigate the issue of waste generate by construction industry.

2.3 To determine the several factors lead to the waste generation and the success for recycling and demolition of construction waste.

2.4 To determine which construction waste can be recycling and which construction waste cannot be recycle.

1.6 Research Methodology

Literature Review

I will carry out my research by conducting literature review to further understand and be more familiar on the title and scope of research that I had chosen. I will try to read ad much information as I can about my topic which mainly obtains from internet, journal, books, newspapers, magazine and reference books. My literature review focus on the ways to recycle construction waste material, cause an effect of construction waste material and construction waste material pollution issue. As an overall picture, I carry out literature review to furnish myself on the construction waste management scope in our country.

Questionnaire

As for this research on construction waste in Malaysia, I will conduct questionnaire which mainly focus on main contractor, developer and sub-contractor. I will give out my questionnaire to about 70 construction firm to help me complete my survey question. I expected that I will receive about 30 respondents to enable me to analyze on the result and continue carry out my research study. The survey questions are design based on the aim and objectives that is stated earlier.

Interview

Interview will be conduct with main contractor or site agent to further understand their ways to remove construction waste in the site. Throughout interview, I can find out the difficulties of handling construction waste. Contractor can share some experience on how to reduce the waste or how to remove the waste on construction site to me and I think this might be helpful for me to do my research.

Chapter 2: Literature Review

2.1 Definition of waste

Nowadays the amount of construction waste contribute in a development country is extremely high. As compare to other waste produce by other industries, the construction waste is the highest generation of waste. Waste can be simply define or describe as the material which is produce by human or from industry which does not has residual value ( Serpell and Alarcon, 1998). There are a lot of definitions to describe waste as show below:

Waste can be defined as “that which can be throw away or dispose without reducing customer value”.

(Polat and Ballard, 2004)

The loss or damage of whatever kind of resources is considered as waste. The waste on materials, time (labour and equipment), and capital is mainly conducted by activities that generate direct or indirect costs but do not increase any value to the last product from the point of view of the customer.

(Formoso et al., 2002)

Any substances or objects that are mainly for disposed or intended to be disposed or are needed to be disposed off by the provisions of national laws are defined as waste.

(The Basal Convention, 1989)

The by-product which is generated or remove from a construction work, renovation work and demolition work or sites of building and civil engineering structure is consider as waste.

(Cheung, 1993)

For any substances or article which are need to be disposed of as being broken, worn out, contaminated or otherwise spoiled is consider as waste.

(Section 75 of U.K. Environmental Protection Act (EPA), 1990)

Table 2.1 Definitions of waste

There are many waste generate everyday in a construction site such as construction waste, material waste and solid waste.

Construction waste:

Construction wastes are the wastes that are generated from the various activities carry out from the construction which is relatively clean and heterogeneous building material (Tchobanaglous et al., 1993). It is also define as the waste which includes the delay in time consuming, unsafely, rework, unnecessary transportation journeys, far distances, improper management of programme and poor constructability (Lee, et al., 1999). Besides that, (Peavy et al., 1985) indicated construction waste as the waste which is conducted from building works, demolition works and refurbishment works for individual housing, commercial building or other structures.

According to (Shen et al., 2004), Construction wastes are arising from the different types of construction activities including the excavation, civil and building construction, site clearance, demolition activities, roadwork and building renovation which result the wastes in the formation of building debris, rubble, earth, concrete, steel, timber and mixed site clearance materials.

For the new construction wastes, it is composed primarily of mixtures of unused or damaged raw materials as well as off cuts (discarded cut material) and packaging (Magdich, 1995).

Materials waste:

Materials waste is mean by “whatever material that are far away from earth materials which requires to be transported elsewhere from the construction site or used among the construction site itself for the objective of land filling, incineration, recycling, reuse or composting, other than the intended specific purpose of the project due to materials damage, excess, un-reuse, or non-compliance with the specifications or being a by-product of the construction process” (Ekanayake & Ofori, 2000). Material wastes are categorized by the activity which are over-ordering, overproduction, wrong progressing, unsatisfied storage, manufacturing defects and theft or vandalism by human ( Garas et al., 2001).

Solid waste:

Wastes generate from human and animal activities are called solid waste. Wastes establish by public authorities for final disposal, including hazardous waste, liquid-solid sludge from industry and water/waste water plants are within this definition (Kiely , 1997). Solid waste is also to be said as the waste which is in solid form that are unusable or unwanted generally conducted by human activities (Peavy et al., 1985).

2.2 Issue of Waste

When due to the issue of waste, the construction waste is or will subsequently become a serious environmental issue in many cities and countries all around the world (Chen et al., 2002; Ferguson et al., 1995; Shen et al., 2000, 2002; Smallwood, 2000; Wong and Tanner, 1997). (Faniran and Caban, 1988; Kibert, 1994; Ferguson et al., 1995; Graham and Smithers, 1996; Guthrie et al., 1999; Symonds, 1999; Lawson and Douglas, 2001.) Stated that waste management for construction and demolition activities has become the major environmental problems in many municipalities. Whenever there is a construction activities carry out, there will produce waste.

Waste from the construction industry will cause global warming, environmental pollution and degradation (Jones &Greenwood, 2009). Environmental problems in many big cities are also cause by the construction waste generated in construction activities (Begum et al., 2006; Chen et al., 2002; Teo & Loosemore, 2001). There are several construction materials which contribute the cause of wastes such as steel reinforcement, premixed concrete, cement, sand, lime and premixed mortar, bricks and blocks, ceramic tiles pipes and wires Formoso et al., (2002). Based on the analysis on sources of wastes concluded that a high amount of material wastes is generated due to the flow of activities like material delivery, inventories and internal transportation and handling, which are usually neglected by site management (Formoso et al., 2002). A research from Environmental Protection Department stated that a daily average of 37,690 tonnes of Construction and Demolition (C&D) wastes was conducted (EPD, 2000a).

Besides that, due to the development country which the construction industry activities increasing rapidly and shortage of sustainable landfill sites, the construction wastes are becoming a serious problem forcing the professionals and researchers to focus on the way to reuse the construction wastes (Masood et al, 2002). Globally estimate that many landfill sites around the world will receive 10-30% of construction and demolition (C&D) waste frequently (Fishbein, 1998) while (Magdich, 1995) stated that construction and demolition wastes to be throwing to the landfills will contribute 25 percent from all the wastes. There are about 1-10% of the purchased construction materials will be leave at the site for the residential projects as waste (Bossink and Brouwers, 1996). Recent research which carry out in UK stated that at least 10% of all raw materials delivered to the sites will be wasted in the case of damage, loss and over-ordering (Guthrie et al., 1998). In the year of 2005, our landfills will be fully dispose of waste and the construction industry will no longer depend on landfills to dispose waste (EPD, 2002a).

Other wastes are easy to be handled but for the construction waste, it is more difficult to be reuse or recycle due to the high levels of contamination and a huge degree of heterogeneity. (Bossink and Brouwers, 1996) say that construction waste also contains an extremely high amount of chemical wastes which is harmful and hard to be handling.

Usually for the construction waste generate in construction activities will be dump to landfills and in recent days construction waste is recommended to be recycle to recognize its value and potentials of reusing them in future construction project (Trankler, et al., 1996; Peng et al., 1997). As for the total landfill’s wastes, construction and building activities takes 30% of the total volumes in the States while UK adds more than 50% and Australia takes 20%-30% (Teo and Loosemore, 2001). Research on the construction and demolition wastes has been done which indicate that about 15%-30% of all solid waste by weight and more than 90% of this waste is from landfill in the gulf region, especially in Kuwait (Kartam, et al. 2004).

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Figure 2.2 Hierarchy of construction and demolition waste (Peng et al., 1997).

There are limited practices among the construction sector on the waste minimization, reuse and recycling method because of the building materials which are at relatively low cost (Begun et al 2009). There is no forcing that the construction companies must practice sustainable resource and waste management which conclude that illegal dumping is still an issue for the authorities (Begun et al 2009).

As this figure 2.2.1 is concern, it specified that for the solid waste, it contribute the most among the other waste produce in a construction industry in Malaysia.

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Figure 2.2.1 Percentage of solid waste in 1994 by ¼ˆHassan et al.¼Œ1998).

2.3 Factors of waste generation

2.3.1 Classification of waste

There are classifications of wastes in the construction industry. Research from the pass indicated that the material waste will occur or appear throughout the construction project no matter in initial stage, design stage, construction stage or operation stage (Craven et. al., 1994; Faniran and Caban, 1998; Gavilian and Bernold, 1994; Spivey, 1974).

Basically for the building construction waste there will divide into two categories namely structure waste and finishing waste (Skoyles and Skoyles, 1987). Structure wastes are those wastes such as concrete fragment, reinforcement bars, abandoned timber plate and pieces. On the other hand, for finishing wastes, it included a wide range of waste materials which is generated during the finishing stage of the building (C.S.POON*, ANN T.W.YU and L.JAILLON 2003).

Furthermore, wastes are being arranged into specific categories like demolition materials, packaging materials, wood, concrete, asphalt, garbage and sanitary wastes, scrap metal, products, rubber, plastic and glass, and pesticides and pesticide containers (Spivey, 1974).

Singapore defined the classification of construction material waste into three major categories namely material waste, labor waste and machinery waste (Ekanayake and Ofori, 2000):

Material waste: Any kind of materials which is unused and rejected as worthless or unwanted.

Labor waste: Simply mean that the waste conducted by laborer such as concrete wasted due to unsatisfied workmanship, brick lay wrongly and broken of floor tiles.

Machinery waste: Machinery which is order to the site but did not carry out the construction activities.

Classification of solid waste is as below:

Municipal waste which the wastes are paper, plastics, food wastes, ashes, and special wastes include Street sweepings and dead animals.

Industrial waste which the wastes are timber, demolition and construction waste, treatment plant waste, hazardous waste.

Hazardous waste which the wastes are radioactive substances, chemicals, biological waste, flammable waste and explosives.

(Kiely , 1997).

2.3.2 Construction Industry Waste Generation

A study on the generation of construction waste in the construction industry is very important. Waste generates in many kind of situation and it is important to be identified to reduce and improve the waste management. Nowadays a lot of countries were developing well in construction industry and cause the generation of huge amount of construction waste. Demand for houses and major infrastructure projects make the amount of construction waste keep increasing rapidly which will cause environmental issue (Nasaruddin et. al., 2008; Siti and Noor, 2008). Construction and demolition wastes surpass the volume of municipal wastes in most of the countries. This simply means that construction activities generate and produce a large amount of waste (Sim Lee Gaik, 2005). (Graham and Smithers, 1996) stated that as long as a construction activities or project is concern, there are several factors which will lead to the production of waste.

Basically, it is often that the construction wastes are come from the result of human error in design, procurement method, material handling, residues of raw materials and unexpected change in building design (Bossink and Brouwers, 1996). Generally about 10% of the materials delivered to construction site will become wastes at the end of the construction activities (Magdich, 1995). A study contribute that the largest waste generated materials or component is woody (Goetz, 1998).

As for other countries, waste generation is show as below:

Hong Kong generated the major solid waste in construction industry and in the year of 1998, it generated approximately 32,710 tons of construction and demolition (C&D) wastes per day (Poon et al., (2001).

Greece surpasses 3.9 million tons of construction and demolition wastes for the year of 2002 which will continue increase the amount of waste subsequently (Fatta et al., 2003).

Australian landfills have 20% to 30% of construction waste out of all wastes are being dispose (Craven et al., 1994).

Brazil is to be saying that the amount of construction waste generated will be 20% of all materials delivered to site (Formoso et al., 2002).

United States Environmental Protection Agency (USEPA) mention that the amount of 124 million metric tons of building-related construction and demolition wastes or 1.2kg per person per day were produced in the year of 1996 (Weber et al., 2002).

India has the total generation of construction waste about 14.7 million tons per year as stated in Central Pollution Control Board India (Pappu, 2006).

Country

C&D Wastes (percentages %)

The Netherlands

26

Australia

20-30

United States

20, 23, 24, 29

Germany

10

Finland

13-15

Table 2.3.2 C&D Wastes as Percentage of All Solid Wastes Entering Landfills in

Various Countries (Source: Bossink and Brouwers, 1996)

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Chart 2.3.2 C&D Waste Generation in Million Tons

Waste generate in

Percentage

Tourist Hotel and Industrial Projects

19%

Commercial Projects

16%

Low Rise Building

13%

Government Projects

11%

Tunnel and Infrastructure

8%

High Rise Building

33%

Table 2.3.2.1 Cumulative Percentages of Projects Generating Construction Waste in Egypt

(Mohd Firdaus Bin Mustaffa Kamal, 2009)

The involvements of waste generation are divided into five sections such as design, procurement, materials handling, construction/ renovation and demolition. The table below shows the different type of project phase which cause waste generated: (Graham and Sniithers., 1996)

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Table 2.3.2.2 Causes of waste in different project phase

The construction and demolition wastes generate rubbish, wood/ related products and miscellaneous wastes where their percentage of waste generation is as follow:

Rubbish 40%-50% such as concrete, asphalt, bricks, blocks and dirt.

Woods and related products 20%-30% such as pallets, stumps, branches, forming and framing lumber, treated lumber and shingles.

Miscellaneous wastes such as painted or contaminated lumber, metals, tar-based products, plaster, glass, white goods, asbestos and other insulation materials, and plumbing, heating and electrical parts.

Tchobanoglous et al. (1993)

2.3.3 Wastes in Malaysia

Malaysia, a developing country wishing to achieve status by 2020 is facing a big problem and challenge of decoupling economic growth and waste generation (National Economic Advisory Council, 2010). Construction waste generating in Malaysia is becoming more and more pressing issue (Begum et. al, 2007; Begum et. al., 2010). (Recycling Today, 16 March 2004) indicated that Malaysia has a subsequently high waste generator from the construction industry. It can be said that Malaysia’s construction waste is one of the largest waste rate and yet despite a number of government policy initiatives to address this problem, suitable resource and waste management on site remains a low priority for the majority of the contractors (Begum, 2009).

Due to the rapid development and urbanization happen in Malaysia, our country produces about 25,600 tonnes of waste daily (Fazleena Aziz, 2010). There are five states in Malaysia which produce 70% of the total amount of waste in the country and there are Kuala Lumpur, Selangor, Pahang, Terengganu and Kelantan (Grant, 2001). 30 construction sites are conducted in a study which identified six types of waste materials namely concrete (12.32%), metals (9.62%), bricks (6.54%), plastics (0.43%), woods (69.10%) and others waste (2%). Among these wastes, woods contribute the most in our country (Faridah et. al., 2004). 28% of municipal solid waste and construction waste been generated in the central and southern regions of Malaysia (Mohd Nasir et Al., 1998). Overall summary of 16,000 tons of domestic waste is produced per day by local communities and the amounts per capita change from 0.45 to 1.44 kg per day which very much depending on the economic status of the areas concerned. This simply mean that waste generate about 1kg per capita per day (GAIA Global Meeting, 2003). Based on a research from Alam Flora Sdn. Bhd., there are only 76% of solid wastes are able to be collect back in Malaysia and only about 5% being recycle, with the rest of 95% disposed at the country’s 112 landfills (Alam Flora Sdn. Bhd., 2007). For our country Malaysia, it is quite surprise to say that the Government spends RM400 million per year on waste disposal and the waste is only refers to municipal solid waste which is a huge amount of money (The Star, 2005).

Another issue happen in Malaysia is illegal dumping. Seberang Perai of Pulau Pinang stated that there are illegal dump site near along the road which is a very irresponsibility way of clearing the construction wastes (Faridah et. al., 2004). Besides Seberang Perai, the issue of illegal dumping is happening rapidly all over Malaysia (Yahaya and Larsen, 2008). Another study done in Johor which conclude that there are 42%-46% of illegal dumping sites are of construction waste (Rahmat and Ibrahim, 2007). Recent news indicated that almost 30 tons of construction waste was found to be dump illegally in tropical mangrove swamp near Bandar Hilir, Malacca and construction debris problem near roadside at Section 17, Petaling Jaya, Selangor (The Star, 2011; The Star, 2012). Those irresponsibility actions of illegal dumping will cause risk to human health and environmental problem (Faridah et. al., 2004; Rahmat and Ibrahim, 2007).

The “National Strategic Plan for Solid Waste Management” was form in 2005 which mainly focus on solid waste management in peninsular Malaysia and the duration is until 2020 providing the foundation for the subsequent years (United Nations Development Programme, 2008).

2.3.4 Purpose of Waste Management

The main purpose of conducting waste management is to reduce/ remove the amount of waste produced and in the same time reducing disposal costs and the environmental impact (Pitt et al., 2002). Waste need to be carries out by using recycle and reusing method so that it will not affect the environment factors and improve our future life. According to (Woolley, 2000), with the help of waste management in term of reducing, reusing and recycling of C&D waste, it will help to increase the lifetime of landfills and reduce exploration of natural resources.

One of the strategies to reduce waste is by recycling as it contributes to three main advantages (Edwards, 1999):

Reduce demand for new resources

Reduce transport and production energy costs

Use the waste which would otherwise he lost to landfill sites.

It is important to carry out waste management from now on although a very small amount of construction and demolition wastes is now recovered by waste management, for sure there will be greater amount of wastes to be recycle in the future in such a way that higher tipping fees, mandatory landfill diversion legislation and the success of entrepreneurs in processing both source-separated and mixed wastes (Tchobanoglous et al., 1993). As by using the recycling method for construction waste, it can help to decrease the demand on land for disposing the waste and also help to conserve natural materials and to reduce the cost of waste treatment prior to disposal (Poon, 2002). Waste management is used for a sustainable development which meets the needs of the present without compromising the ability of future generations to meet their own needs (Brundtland, 1987).

2.3.5 Waste Management

It is a major problem suffered worldwide about the management of construction waste (Adam, 2004). Recycling of construction wastes simply mean that the separation and recycling of recoverable waste which are form during the construction and remodeling stage (Mohd Nizam Bin Yusoff, 2010). Research indicated that 90% of the construction wastes can be recyclable to be reused (Mohd Nizam Bin Yusoff, 2010). The main point of view that will cause the waste generation is by design stage. Design stage will taken into control of materials waste on construction sites as it is taking a central role to help minimizing waste produced (Shen, et al., 2004). To manage the construction wastes well, the method of managing is very important as it should be part of the project management functions and involve employees’ participation (Shen and Tam, 2002).

A lot of various management methods have been applied and discuss from previous research in order to improve the control on construction wastes (Sim Lee Gaik, 2005) and (Koskela, 1992; Alarcon, 1997) mention that many methods have been drawn up and developed such as in the way of policy and programmes to help to reduce the construction waste. Construction management plan is introduce to improve materials resource efficiency by carry out reuse, recovery and recycling as well as to minimize the issue of illegal dumping by properly introduce the waste removal processes (Defra, 2009).

As for a successful waste management, the construction waste should not be directly disposed but it needs to pass through several processes before being disposed. The method to treat the proper waste management is to follow the waste management hierarchy (Peng et. al., 1997). By following the concept of waste management hierarchy it will give advantages to the environmental and economy problem to a country (Tchobanoglous and Keith, 2002).

Figure 2.3.5 Waste Management Hierarchy (Source: Peng et. al., 1997)

Another waste management methodologies in the form of hierarchy in descending order from reducing waste, reusing waste, recycling waste till disposing waste where the first three options are not possible (Faniran and Caban, 1998).

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Figure 2.3.5.1 Waste Management Hierarchy

Besides that, there is a method of controlling waste on building sites which concentrate on the procedures as part of the project management on a convention basis (Formoso et al., 1999). A type of waste management namely Site Waste Management Plan (SWMP) will help to provide a guideline to a contractor or project manager to estimate and record down the amount and type of construction waste which will likely be produced in a construction project. It will also help to set up an appropriate management action that will reduce the amount of waste to be sent to landfill (WRAP, 2007).

Furthermore, (Tchobanoglous et al., 1993) introduce Material Recovery Facilities (MRF) is a waste management which used for commingled construction and demolition wastes. The brief procedure of using this kind of waste management is as below:

It is carrying out on the site where the wastes are spread out on an open area and all the wood is removed manually. The wood is then taken to a huge wood grinder where this machine is to convert the wood into wood chips. Next, the waste will be picking up with a front-end loader and discharged onto a two stage vibrating screen. As for the first screen, it is used to remove large pieces of concrete, roots and similar materials while for the second screen, it is located immediately below the first screen which is used to remove finer pieces of broken concrete and other smaller-sized contaminants. Then the fine material will be transmitting to a second vibrating screen where additional fine contaminants are removed. Lastly, the final product will be comparatively clean the dirt to stockpiled for sale. For the material removed by the screens will be stockpile and throw to the landfill for disposal (Tchobanoglous et al., 1993).

Moreover, Lifecycle Assessment (LCA) is introduce as a method to assess the environmental effects of the overall system from the extraction of raw materials from manufacturing processes, product use and final disposal (Powers and Williamson, 2004). In the past few years where the Lifecycle Assessment (LCA) has been enlarge to cover larger processes and services for example waste management but this LCA application is limited in the construction sites (Craighill and Powell, 1999). A lifecycle inventory for another strategy for waste management is constructed by (Craighill and Powell, 1999). These results are translated into environmental and social impacts for example global warming, road congestion and employment. These impacts will then further analyze by using economic evaluation and multi criteria evaluation techniques. After being analyze, both produce the same results which stated that the reuse of demolition waste has the overall impact followed by a combination of reuse and recycle with landfill the least desirable option. As a conclusion, by using the lifecycle assessment, the construction industry could become more sustainable by strategically replacing primary materials with recovered materials. With the help of lifecycle assessment model, it will help the industry make waste management decisions that favor the environment. Below are the lifecycle of construction wastes:

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Figure 2.3.5.2 Lifecycle of Construction Wastes (Source: Craighill and Powell, 1999)

There is also a waste management on concrete is recommended where if the appropriate waste management is carry out correctly by recycling and reuse of concrete at work site. It will be more economical and easy to be handled. An overall system for recycling for example identification of source, gathering of construction waste and aggregate preparation, therefore has to be developed followed by mix design, suitable construction techniques and design methods to form a strong and durable concrete structure (Masood et al., 2002).

To make sure that the construction wastes is being reduced; the best way is to carry out a waste audit which includes tracking the wastes generated and the disposal costs. Meanwhile in the beginning stage, design phase and careful control of purchasing and inventory could prevent the waste of raw materials which will help to reduce construction waste generation (Magdich, 1995).