A study on construction and demolition wastes from buildings in Seberang Perai Faridah A.H.Asaari 1, Hasmanie Bt Abdul Halim 2, M Hasnain Isa 1 1 School Of Civil Engineering, Engineering Campus, Universiti Sains Malaysia,14300,Nibong Tebal, Penang. 2 Faculty of Civil Engineering and Natural Resources, College University of Engineering and Technology Malaysia (KUKTM), 25000, Kuantan, Pahang ABSTRACT: Construction and demolition (C&D) waste is defined as solid, bulky, largely inert waste resulting from the construction, renovation or demolition of buildings structures. As a whole, C&D wastes are considered to be composed of inert materials that will not leach into the groundwater. Even though C&D waste present a lower risk to human health and the environment compared to municipal solid waste, the bulky waste definitely consume a lot of space at landfills. C&D waste will increase from time to time in proportion to the development of a town and country. Thus, the necessity of finding appropriate solution to C&D waste destination must be clear. Hence, a study on the C&D waste generated has been conducted aiming to establish data on material composition, cost of handling and disposal, and the extent of waste recovery and type of disposal. A survey of 30 construction and demolition projects throughout the Seberang Perai area was made between August 2001 and January 2003. In addition, in order to get the representative data of C&D waste, public and private authorities were interviewed, and field study at Pulau Burung Sanitary Landfill was carried out. Key words: Construction and demolition (C&D) waste, material composition, landfill disposal, recovery, recycling. 1 INTRODUCTION The purpose of this study is to characterize building related C&D waste generated based on 30 Seberang Perai area consists of three districts which selected construction sites in Seberang Perai. A better understanding of the composition of C&D waste include Seberang Perai Utara, Seberang Perai Tengah, and Seberang Perai Selatan. The total population in 2001 is about 736,306 and its population can be gained by examining its various components. C&D waste can be classified based on two sources: growth rate is 1.8 percent (Penang Town Planning new constructions and demolitions. While the types Department, 2002). This means that Seberang Perai of waste generated from these two sources are similar, the amount of each material produced is differ- will be facing a steady increase in population growth that will definitely demand the development of new ent. Furthermore, C&D waste can be classified into residential areas as well as commercial and institutional buildings (Hasmanie, 2003). An increase of materials that could be recycled, reused and inert landfill materials. Generally, the generation and development projects will consequently increase the composition of C&D waste is site specific and depends on design, location and previous use of the amount of construction and demolition (C&D) waste generated. site. C&D waste composes of solid, bulky, largely inert waste resulting from the construction, renovation or demolition of buildings structures. However, it 2 METHODOLOGY has been very difficult to obtain records and data on In order to get representative data of C&D waste, this kind of waste since C&D waste are dumped about 30 construction sites (operated between August 2001 until January 2003) were selected and both legally and illegally, and in different places such as near road sides, illegal dumpsites from time questionnaires were sent out to site responsible personnels. In addition, related information from Majlis to time in proportion to the development of the state. Reducing, reusing and recycling of C&D waste appear to be possible alternatives that will increase the Perbandaran Seberang Perai (MPSP) concerning C&D waste and data from Pulau Burung Sanitary lifetime of landfills and reduce exploration of natural resources (Woolley, 2000). AWAM-2004 4E05 1
Landfill (January 2002 January 2003) database were also collected. The questionnaire was developed based on the types of project, project period and area, types and quantity of waste generated, and method of waste disposal. Besides the sent questionnaire, information for this study was also partly collected from detailed interviews held with the public and private authorities in the Seberang Perai area. The face to face interviews were conducted in the early stage of the study in order to get the necessary data and information about construction and demolition waste generated and a general view of their waste management in this study area. The interviews were designed to provide overall information on; i) Materials: quantities, types and composition of wastes generated. ii) Transport and handling: waste separation techniques, transport network and cost, disposal methods and charges. iii) Possibility of waste minimization: reduce, reuse and recycling. C&D waste is bulky, cannot be compacted and will take up permanent space in the landfill. As noted in Figure 1, the industrial waste represented the largest portion (78.21 percent) of solid waste that was disposed of, followed by domestic waste which was 14.75 percent of the total solid wastes. This is because Seberang Perai is the most developed industrial area in the northern region of Peninsular Malaysia. Commercial waste contributed only 3.68 percent of total solid waste disposed and followed by other wastes at 2.8 percent. Other Waste 2.80% C&D Waste 0.40% Commercial Waste 3.68% Domestic Waste 14.75% Garden Waste 0.17% Industrial Waste 78.21% Figure 1. Waste disposal at Pulau Burung Landfill (% by weight) 2.1 Field Study at Pulau Burung Sanitary Landfill Data for the C&D waste that has been disposed in Pulau Burung Sanitary Landfill (PBSL) was collected based on daily records from August 2001 up to January 2003. It was quantified based on their weight. In order to get the data on waste composition, wastes from three randomly selected C&D waste lorries were analysed. Firstly, the waste from each lorry was sorted into four categories which were: i) concrete and bricks, ii) steels and aluminiums, iii) woods, and iv) others (glass, electrical and plumbing fixtures, tiles etc.). Secondly, the weight for each category of waste material was determined to obtain the percentage of waste composition. 3 RESULT AND DISCUSSION Discussions of results will be according to the following subtopics: 3.1 Data From Pulau Burung Sanitary Landfill Figure 1 shows that C&D waste accounted for 585.4 tonnes or 0.4 percent of the total solid waste disposed at Pulau Burung Sanitary Landfill within the 9 months study period. Although C&D wastes was the second smallest portion of the total solid waste disposed, consideration of effective and efficient management is required to reduce or minimize it because Figure 2 displays the average composition of C&D waste materials disposed at the Pulau Burung Sanitary landfill. This C&D waste composition was generally based on the average of three loadsamples, which were sorted and weighed at the landfill site. Concrete & Bricks 60% The percentage of concrete and bricks is considerably higher, as may be expected as the structure of buildings are mostly based on concrete and bricks. Wood component included stumps, plywood, laminates and scraps, which contributed about 20 percent of C&D waste disposed. Metal components included pipes, reinforced bar, steel, aluminum, copper, brass and stainless steel. Metal components contributed about 15 percent of the C&D waste composition and were followed by the other C&D wastes, which were about 5 percent. Other C&D waste comprised of glass, drywall, fixtures and ceramic tiles. AWAM-2004 4E05 2 Other 5% Metals 15% Figure 2. C&D composition at PBSL (% by weight) Wood 20%
3.2 Data From Questionnaires And Survey For analysis purposes, building C&D waste is divided into five categories, which include residential, commercial and institutional constructions, and commercial and institutional demolition projects. Institutional buildings include schools, university and government offices, and commercial buildings consist of public and private commercial buildings such as shop lots, food courts and public markets. Table 1 shows the C&D waste generated from the five different project categories. From the survey, 70.46 percent of wastes were generated from fifteen institutional construction sites representing the largest waste generation in the stream. Residential building construction contributes about 17.43 percent of waste generated from eight sites, followed by commercial construction at 5.06 percent. In this study, only two demolition projects have been gathered and analyzed due to the lack of building s being demolished compared to the new building construction in Seberang Perai area. These two demolition projects represented about 7.04 percent of the total C&D waste generation. Table 1. &D waste generation by individual sectors from questionnaires Construction/Demolition Projects Number of Projects Contribution to Total C&D Waste Generated (% of total amount) Residential Construction 8 17.43 Commercial Construction 5 5.06 Commercial Demolition 1 2.76 Institutional/Government 15 70.46 Construction Institutional/government 1 4.28 Demolition TOTAL 30 100 3.3 Waste from Construction Projects Estimation of construction waste generation for this analysis have been done by reviewing the number of construction sites, then estimating the amount of C&D waste material produced by each type of building construction. Although the building construction and demolition samples are very limited in this study, selection of the common types and size of projects can be useful for making early estimates of C&D waste generation for certain types of construction projects. Table 2 shows the amount of construction waste generated from fifteen institutional/educational project sites. A total of 3,702 tonnes of waste were produced. The main components of construction waste include concrete, metals, bricks, plastics, woods, and other waste such as drywall, tiles, glass, and trim pieces of roofing materials. Wood represents a major portion of C&D waste components with the amount of 2,558 tonnes or 69.1 percent of total C&D waste generation from institutional construction projects. The majority of wood component are from plywood and engineering wood, which were used as formwork during building construction works. Table 2. C&D Waste Generation from Institutional / Educational Construction Activity from Questionnaires Concrete 456 12.32 Metals 356 9.62 Bricks 242 6.54 Plastics 16 0.43 Woods 2,558 69.10 Others 74 2.00 TOTAL 3,702 100 Concrete and metals make up to 12.32 and 9.62 percent respectively, followed by bricks at 6.54 percent. Other waste and plastics, contribute about 2.00 and 0.43 percent of the total C&D waste respectively. Table 3 shows the breakdown, in percent of total, of material composition for residential construction waste generation. Table 3. C&D Waste Generation from Residential Structures by Construction Activity fom Questionnaires Concrete 230 25.11 Metals 92 10.04 Bricks 126 13.76 Plastics 17 1.86 Woods 436 47.60 Others 15 1.64 TOTAL 916 100 Again, wood is the major contributor of waste composition at about 47.60 percent, followed by concrete and bricks at 25.11 and 13.76 percent, respectively. Plastics and other wastes contribute a small portion of waste generated at residential construction site with only 1.86 and 1.64 percent, respectively. Table 4. C&D Waste Generation from Commercial Structures by Construction Activity From Questionnaires Concrete 68.4 25.74 Metals 27.0 10.16 Bricks 34.3 12.91 Plastics 4.2 1.58 Woods 124.0 46.67 Others 7.8 2.94 TOTAL 265.7 100 AWAM-2004 4E05 3
Table 4 shows the similar component of construction waste. There are about 265.7 tonnes of total construction waste generated from five commercial construction sites. Similar to the C&D waste generated from institutional and residential construction projects, wood material also become the major component of waste generated from the commercial construction projects. 3.4 Waste from Demolition Projects Table 5 shows the details of waste quantities and composition generated from institutional demolition activities. Table 5: Material Composition from Institutional/ Educational Demolition Project from Questionnaires Concrete 50 22.32 Metals 40 17.86 Bricks 80 35.71 Plastics 5 2.23 Glass 5 2.23 Woods 40 17.86 Others 4 1.79 TOTAL 224 100 Demolition wastes included a wide range of materials such as concrete, metals, bricks, plastics, glass, woods and other products generally used in the building industry. Actually, this was an old school block demolition project. It has been estimated that this building demolition accounts for approximately 224 tonnes or 4.48 percent of total C&D waste generation from thirty sites. The structure of this building was mostly based on concrete and bricks. Basically, the concrete was from building structures such as column, beam and floor, whereas bricks were from demolished walls. Wood and metals were the second major component of demolition waste generated. The metals were from reinforcement bar, door and window grill, and electrical and plumbing pipe or conduit, which were recovered and sorted during demolition work. Plastics, glass and other materials were found as a minor component of waste generated from demolished building. Bricks and concrete represented as the two largest components of waste generated at 35.71 and 22.32 percent respectively followed by woods and metals both at 17.86 percent. However, plastics, glass and other waste materials contributed a small portion of waste generation at 2.23 and 1.79 percent, respectively. Table 6 shows the C&D waste generated from commercial demolition project. Table 6. Material Composition of Commercial Demolition Project from Questionnaires Material Percentage of Total Concrete 45 31.03 Metals 70 48.28 Bricks 5 3.45 Plastics 5 3.45 Glass 5 3.45 Woods 5 3.45 Others 10 6.90 TOTAL 145 100 This data resulted from a demolition project, which involved a demolished food court building. The contribution of C&D waste, made by this demolition project is estimated about 145 tonnes or 2.76 percent of total C&D waste generated in this study. In this case, metals were the largest portion of C&D waste due to the major metal-based structure such as steel, aluminum, and reinforcement bar from the tear down of reinforced concrete structure. Therefore, the C&D waste generation and composition of demolition projects depend on the design, types and size of building. In addition, the demolition method also affected the quantities of C&D waste generation. Since this is a one level building, therefore, the conventional method was used for demolishing the structures. The usual demolition method involved demolishing all the beams, columns and floor slabs using backhoe, followed by grubbing up pile caps and unused drains. All the materials that may be reuse and recycled were collected and separated on site. The total of C&D wastes generated from these thirty sites is summarized in Table 7. Table 7: Quantities of Waste Material Composition from Construction and Demolition Activities from Questionnaires Material Construction Demolition % Total Percentage of Total Concrete 754.40 15.45 95 25.68 Metals 475.00 9.73 110 29.73 Bricks 402.30 8.24 85 22.97 Plastics 37.20 0.76 10 2.70 Glass 0.00 0.00 10 2.70 Woods 3,118.00 63.85 45 12.16 Others 96.80 1.98 15 4.05 TOTAL 4,883.70 100 370 100 3.5 Cost of C&D Waste Handling and Disposal Removal of C&D wastes from site will incur labour, storage and transportation costs, and landfill dumping fees as well. The cost of removal and disposal could be significant. AWAM-2004 4E05 4
Table 8 shows the average costs of total projects and waste handling, transport and disposal within those thirty projects, which were obtained from the questionnaire carried out. Table 8. Average cost of Total Projects and Waste Handling, Transport and Disposal from Questionnaires Cost of Total Project Nos. of Constr. /Demoli Projects Cost of Waste Handling, Transport and Disposal for Each Project Less than RM 1,000,000 2* RM 5,000 RM 10,000 RM 1,000,000 - RM 5,000,000 5 RM 3,000 - RM 10,000 RM 5,000,000 - RM 10,000,000 8 RM 5,000 - RM 15,000 RM 10,000,000 - RM 20,000,000 5 RM 10,000 - RM 30,000 RM 20,000,000 - RM 50,000,000 8 RM 20,000 - RM 50,000 RM 50,000,000 - RM 100,000,000 2 RM 50,000 - RM 70,000 *Demolition projects Cost of waste handling, transport and disposal mainly depended on the amount of waste generated on site or based on size of the project. From the questionnaire, the average cost of waste handling, transportation and disposal were about 0.1 to 0.3 percent of the total project cost. This involved cost of labour, transport, and landfill charges. For instance, at Pulau Burung Sanitary Landfill the charges are RM 32.00 per tonne for C&D waste. Trucking and transportation costs were estimated based on distance and time consumed per each trip. The construction industries were extremely concerned about time and costs. The responsibility for these outcomes rests with the project manager. It will be very impractical to consider waste reduction unless the time and effort spent in recycling and reducing waste improves the progress of the project. Figure 3 illustrates the average of C&D waste that have been recovered and disposed through landfilling, recycling and reusing, burning and burying on site for the thirty construction and demolition projects. There were about 45.51 percent of C&D waste generated being disposed -off at public and private landfill, and other places such as at road side, 35.95 percent have been recycled and reused for existing or other projects, 12.64 and 5.90 percent have been burned and buried on site, respectively. After completion of the project, contractors usually allow private companies to salvage materials or waste that could be recycled or reused from the site. For instance, after demolition activities, a lot of materials have been salvaged, and then resold and reused for constructing a new building of a new project. 4 CONCLUSION This study only concentrated on the C&D waste generated from building construction and demolition projects and excluded C&D waste generated from other civil engineering constructions, namely road and bridge projects. The overall amount of C&D waste arising in these thirty projects from construction activities composed of 63.85 percent by weight wood, 15.45 percent concrete, 9.73 percent metals, bricks and plastics at 8.24 and 0.96 percent respectively. However from demolition activities, C&D waste composed of 29.73 percent metals, 25.68 percent concrete, then, followed by bricks at 22.97 percent, plastics and glass at about 2.70 percent each, and 4.05 percent other waste. In order to minimize the amount of C&D waste generated, there is a need to identify the sources and factors that caused large amount of C&D waste generation. It largely depends on the parties involved in the construction industry including developers, contractors, engineers and architects. In addition, the government should enforce laws on the proper management of C&D wastes. 5 REFERENCES Recycling & Reusing 35.95% Burying 5.90% Burning 12.64% Landfilling 45.51% Figure 3. Average C&D Waste Material Recovery and Disposal Hasmanie Bt Abdul Halim (2003). A Study of Building Construction and Demolition Waste In Seberang Perai, MSc Thesis, Universiti Sains Malaysia. Penang Town Planning Department (2002). Penang Second Development Strategic Plan (2001-2010) Woolly G.R., Goumans J.J.J.M and Wainwright P.J., (2000). Waste Materials in Construction Science and Engineering of Recycling for Environmental Protection, Waste Management Series, Vol. 1, Pergamon. AWAM-2004 4E05 5