Implementation of eco-costs per value ratio (EVR) on construction waste management in Shah Alam, Malaysia

The construction industry in Malaysia which is rapidly growing is indirectly contributing towards the economic influx to the country. However, the waste generation in construction is increasing proportionally with new construction developments. The current construction methods focus on minimal recycling process where most construction wastes are dumped at landfills because construction companies are required to set aside a higher preliminary cost for proper waste disposal. This study focuses on creating a more potential outcome in decreasing the construction waste by implementing eco-costing in development for the construction waste generated from the beginning stages of a project. Therefore, this study discusses the construction waste management using the eco-costing per value ratio (EVR) assessment. The EVR assessment for eco-costing were targeted to the construction waste products from Shah Alam. The analysis included 5 selected sample sites in Shah Alam conducted within the year 2013 to 2017. The findings indicated that EVR index ranged between 0.054-0.1225 for conventional and semi industrialised building system (IBS) method based on five-selected sample of sites. This range signify on current EVR index which will be compared with Malaysian EVR benchmarking in result and discussion. Furthermore this result is useful to evaluate EVR index between residential for construction waste management towards sustainable development.


Introduction
Construction industries consume a large number of raw materials [1]. The types of raw materials used in the industry include sand, aggregates, water, clay, rock, wood and manufacturing goods such as cement, timber, bricks, plaster cement, tiles, drywall, concrete, rebar, ceiling, and metal. As a result, the residual raw material from such a large amount of these resources results in a significant amount of construction waste, which impacts the environment. The total environmental impact of a construction product during its entire life cycle can be determined using the Life Cycle Analysis (LCA) method. EVR is an LCA based technique to analyse the utilisation designs, business procedures, and design outline choices regarding eco-effective esteem creations. According to Firman et al. [2], EVR is used to benchmark products and service systems. The EVR is a marker to sustainable and unsustainable utilization designs, where the eco-cost is an indicator for the natural contamination of products, while the esteem is the cost paid for the product in the market. The EVR ratios can be used to indicate the level of environmental pollution. As such, poor waste management leads to hazardous environmental impacts and financial losses as the companies eco-costs become greater [3] [4]. The EVR method was adopted in this study because the construction waste management at the selected project sites still has room for waste minimisation improvement. Hence, EVR can be used as a tool to reduce and monitor the construction waste throughout the contract period.
Based on the analyses, the selected five projects were not within the range of benchmarks. The EVR benchmark for the Malaysian construction industry is within 0.0024 -0.0028 for typical multistorey projects applying conventional or partial semi-IBS, and up to 0.0014 for projects utilizing full IBS system or projects with exceptionally good waste management awareness and practice [2].

Materials and method
Five project sites (Project A -Project E) in Shah Alam constructed from 2013 until 2017 were selected for the study, which mainly includes residential low rise. The construction involved a wide range of contractors employing conventional and sustainable building materials in their construction systems. The construction method in Malaysia has been based on the conventional timber formwork (including plywood) for many years. However, although the IBS system has started gaining acceptance and encouragement from the government, only a limited number of larger contractors have opted to use it [2]. Majority of IBS systems employed include metal formwork system (steel or aluminium), drywall panels and precast concrete system (for columns, beams, slabs, and wall) which relatively produce less waste. It is important to note that this study is focused on evaluating the ecocosts for waste generated during the construction phase only, and not the full life cycle.
The major construction materials which were taken into account include concrete, timber, reinforcement bars, bricks and blocks, tiles, and plaster. Whereby, waste generated during construction activities at superstructure phase or known the above groundwork was considered for this assessment because waste generated from substructure or below ground and during foundation works were considered minimum consisting mostly of soil. Moreover, the construction projects covered in the data collection process were from the low rise residential, conventional and the sustainable building material adopted systems within the Shah Alam area. The eco-costs considered in this study included; (i) the purchased cost and delivery cost, (ii) labour cost, (iii) wastage disposal cost, and (iv) landfill cost. Besides, cost waste generation rate (WGR), waste index (WI) and waste level (WL) were also identified in this analysis. Major data extracted included (i) Gross Floor Area (GFA), (ii) material order quantities, (iii) material work done quantities from Bills of Quantity (BQ), (iv) construction debris disposal trip record, (v) purchase and delivery costs, and (vi) costs associated with waste generation and total project cost (contract sum). This study assessed the eco-costs of produced wastes.
The first step in quantifying the carbon footprint is to determine the amount of wastage generated and wastage level for each specified material as described below: Wastage level,(W l ) = Total wastage,(T w ) x 100% [2] Total work order, (T wo ) Wastage level (W l ) = The percentage of wastage between projects Total wastage (T w ) = Total wastage amount (RM) during the contract period Total work order (T wo ) = Quantity (RM) material work order Meanwhile, the calculations for each cost are as in the following section.

The purchased cost and delivery cost
Purchased cost and delivery cost (%) = Total wastage cost, (T wc ) x 100% Purchased cost, (P c ) (2) where, Purchased cost and delivery cost (%) is calculated to justify the percentage between total wastage cost and purchased cost.

Purchased cost and delivery cost = Total wastage cost, (T wo ) x purchased cost, (P c ) [2] (3) where,
Total wastage cost, (T wc ) = Total wastage amount (RM) during the contract period Purchased cost, (P c ) = Total material purchased and delivery cost The price of materials used was obtained from the contract department of Setia Alam. However, the price for some materials that were not listed was obtained from various resources. The unit cost in the price list for each material was inclusive of the delivery unit cost.

The wastage disposal cost
Total waste generated by project (month's contract) m 3 (v x n) = w (5) where, Truck volume (m 3 ), (v) = the volume of waste bin Total number of loads for waste disposal, (n) = Total trip of disposal Total waste generated by project per month, (w) = the volume of waste bin x Total trip of disposal (t x c) = Total wastage disposal cost (6) where, Cost per trip, (c) = Cost per single trip Total Trip, (t) = Total trip of disposal

The waste index
Waste index is calculated to justify the index rate by total waste generated between projects divided with gross floor area of a project as shown below: Waste index, (W i ) = w /gross floor area (GFA) [5] where, Gross floor area (GFA) = Total built-up per unit x total units [2]  The cost per trip data provided for project A was manipulated to fit the other 4 project costs as it was assumed to be the same as project A following the range of length. This is because the cost per trip is relatively the same since the location of the dumping ground was within a specific range. However, the cost still depends on the size of the waste bin, falling within the range of RM 150-RM 250. Besides, data for the number of trips was extracted from the Environmental Waste Management (EMS 14001) index calculation.
Total waste volume can be calculated as pyramidal and rectangular shape as below if the construction waste material not placed at a designated area.

Total volume of waste, (vw)=(LxBxH)[6]
where, L = length B = width H = height Landfilling cost = Total waste volume x Cost per volume [2] This above-mentioned equation (9) was also used by [6] [7] in their studies to evaluate the volume of waste produced at site. Based on the data obtained from Perbadanan Pengurusan Sisa Pepejal and Pembersihan Awam (PPSPPA), the landfilling cost was assumed to be approximately RM 200 per m3 of waste [2]. The data for total waste volume was also extracted from the Environmental Waste Management (EMS 14001, 2015) index calculation. This total waste volume required to justify the overall construction waste produced by selected five project sites. Thus, EVR can be described as the total eco-costs divided by the total value of the project as seen below.

EVR ratio EVR = Eco-costs (RM) [2]
Total project cost (RM) (11)  Although this study did not fully include all attributes proposed by [4], it was expected that the costs considered in this study should represent the eco-costs for every project objectively. The attributes that were not included in the scope of the study are the cost of impacts, cost of emission from equipment, and cost of depreciation of equipment. Figure 1 illustrates the process of construction waste disposal at the selected project site. Waste quantity or volume obtained by truck trip.Based on the data collected, the waste classification and justification were only made for superstructures since substructure waste products were of low to moderate level. A total of nine types of waste materials were identified such as rebar, concrete, timber formwork, bricks, plaster cement, tiles, drywall, metal deck roofing, and ceiling. With the large consumption of materials at constructions currently, the implementation of EVR can help developers to keep the construction waste produced during the contract period under control. This would lead to sustainable construction which creates a sustainable building environment and human health through efficient use of resources. Table 1 summarises the spreadsheet on EVR calculation for the selected construction projects in this study.   Figure 2. EVR ratio between five projects.
Based on Figure 2, the EVR index for Project D (0.054) was identified as the lowest among the other projects. The calculated EVR index values can serve as a contributing factor to the betterment of the waste management at the project areas by its developers. Furthermore, the waste index tabulated in Table 1 for Project A to Project E ranges from 0.014% to 0.040%. These index values will aid in monitoring the total waste disposal cost during any stages of the construction period. Besides, the project developers will be able to establish a better resources management plan towards sustainable development.

Conclusion
Construction waste management is an important element in construction for a sustainable development. The intention of this study was to develop a sustainable waste eco-cost model based on case study approach during the construction stage. The detailed assessment of the waste disposal cost saving between the conventional and sustainable building materials was performed using EVR method. The project D that adopted semi industrialised building system (IBS) with combination of shear wall and conventional method obtained better EVR index of 0.054 compare to other projects. However, for overall assessment of EVR index there are few steps of calculation required as above. The assessment provides efficient solutions to handling construction wastes which leads to sustainable construction waste management. Poor waste management can lead to unsafe environmental impact along with financial losses, the increase of the eco-costs for any project [13]. The increase in total waste produced from each material will increase the eco-costs for a project with lower gross floor area (GFA), hence, elevates the EVR index. Therefore, to lower the EVR index, total waste produced should be reduced indefinitely. The lower the EVR index, the better it is for society.