by Anisa Pinatih
With construction waste piling up at an alarming rate in Southeast Asian countries, effective management and minimisation programmes are imperative. Resources recovery such as reuse and recycling should be coupled with prevention of waste generation that reduce virgin material extraction. The use of sustainable materials and advanced technology are among the most promising solutions. High-income countries such as Hong Kong and Singapore take the lead in the region. Indonesia and Malaysia have also adopted similar sustainable practices, despite facing some challenges.
CONSTRUCTION AND DEMOLITION WASTE
Construction and demotion (C&D) waste is made up of components such as concrete, stonework, wood scraps, metallic waste like cables and pipes, asbestos, brick, tiles, ceramics, gypsum, tar and coal tar, plastics and many others. These are by-products of construction, demolition or renovation of buildings that continue to pollute the environment.
Report by the World Bank in 2012 says that annual global solid waste generation is 1.3 tonnes and this is predicted to soar to 2.2 tonnes per year by 2025. Building materials account for 50 per cent of this annual global solid waste. The World Bank 2018 report confirms that the waste is reaching 2.01 tonnes per year, with 33 per cent not being managed properly.
Construction industry extracts a large amount of virgin material and produces a high level of C&D waste.
Real measures should be taken to reduce and to mitigate the negative impacts, but waste treatment worldwide is poor. The World Bank report in 2018 further states that the most common ways to dispose waste are in open dumps and unspecified (most probably uncontrolled) landfills. Recycling waste takes up only 13.5 per cent; and other more sustainable methods i.e., sanitary landfills, composting and controlled landfills occur at only 7.7, 5.5 and 4 per cent respectively.
In addition, the construction industry also consumes high energy and extracts raw materials on a large scale. UN Environment’s Global Status Report 2017 states that the industry uses 36 per cent of the total world’s energy. The Global Material Resources Outlook 2060 predicts that minerals’ extraction will continue to rise, especially for construction in developing economies, including the Southeast Asian countries. The extraction of sand, gravel and crushed rock will reach 55 giga tonnes by 2060; while metal, coal, limestone and wood will also double.
With the circular economy agenda being promulgated worldwide, these extraction and utilisation processes should be coupled with sustainable waste management. The recycling industry, as argued by the World Circular Economy Forum, is indeed growing and will be more competitive, but the scale is too small compared to the mining sector (making up only one tenth of global GDP share).
WASTE MANAGEMENT HIERARCHY: WHERE DOES IT START?
Needless to say, C&D waste has detrimental impacts on the environment as well as other aspects, including health and economy. As the world becomes increasingly concerned about climate change, both developed and developing nations are urged to manage C&D waste properly. Countries in Southeast Asia imposes stricter law; for example, Malaysia drafted RM5 million (S$1.6 million) for environmental offences.
The most common ways to reduce C&D waste is by reusing and recycling, but these do not discourage the generation of waste—only solving the problem and not preventing it. C&D waste can also be generated by faulty design processes, ineffective planning, miscalculations, or by mishandling the materials. If the design and site practices are improved, waste should also be minimised from the outset.
The first order in the hierarchy of waste management should be reducing, so discarding will be the last option. When materials do get discarded, it is then recovered by repurposing, reusing or recycling. Image 2 illustrates a waste management hierarchy proposed for developing nations in Asia.
Waste segregation plays an important role in many Asian countries, especially by the informal sectors. This could be improved by providing facilities and safe environments for waste pickers. Secondary materials industry is growing rapidly because of increasing demand. However, the high labour and technology costs in secondary materials production, as reported by OECD Global Material Outlook 2060, means that this industry will not outpace the primary material industry anytime soon.
Waste Management in Southeast Asia: Snapshots from Hong Kong, Malaysia & Singapore
Treating construction waste, or just waste in general, needs strong budgeting and this is where the trouble lies. Finance remains a challenge in most Southeast Asian countries, both for initial investments and operational procedures that include collecting, transporting, sorting, treating, and ultimately distributing the produced recycled materials and discarding the ultimate waste.
Sustainable waste management is indeed closely related to a country’s economy. Low-income countries spend significantly less on waste management than high-income countries, because the take-on is labour intensive and costly. Many international organisations provide funding to assist solid waste management, such as the World Bank that has given more than $4.7 billion to over 340 initiatives around the world.
To illustrate how waste management is practiced in countries with different income levels in Southeast Asia, we could look at Hong Kong, Malaysia and Singapore. By considering the GNP per capita and populations, Hong Kong is considered as a high-income economy, whereas Malaysia is considered as an upper-middle income economy (World Bank, 2020). Research by faculty members of Universiti Teknologi MARA, Malaysia, that compares the practices in Hong Kong and Malaysia concludes that Hong Kong’s practices have a more positive outlook because of the legal instruments and treatment methods in place. Part of the findings is presented below. I added data about Singapore for the sole purpose of this commentary.
The legal act in Hong Kong covers more areas. It reuses materials and abandons incineration. Inert material is sent to public filling that is subsequently used for reclamation; and decomposable organic waste is taken into the main waste disposal stream. Meanwhile, Malaysia has a recycling scheme, but it is not a priority practice, with rates falling back at merely 5 per cent.
However, this might change soon as Malaysia’s economy is growing rapidly and the government is taking more progressive actions to improve their country’s sustainability such as launching Green programmes like Penang2030 and strengthen their legal instruments.
Recycling and reuse should be coupled with reduction of virgin material extraction, which can be achieved by the use of advanced technology.
As for Singapore, legal act is more comprehensive covering not only the environment but also the public health, sea pollution, transboundary haze pollution and even radiation risks. Similar to Hong Kong, incineration is banned. This is even earlier since 1999. Singapore is leading in sustainability practice because the focus is no longer on managing, but minimising the waste.
Waste minimisation, as defined by the UK Department of Environment, Food and Rural Affairs means reducing waste by preventive measures, which means using less materials in design and manufacture; keeping products for longer use; and using less hazardous materials. Similarly, construction waste minimisation is a systematic waste reduction at source, by avoiding and reducing waste before the physical generation, coupled with reuse, recycling and recovery.
How do sustainable materials help minimise construction waste?
Even in a high-income economy like Hong Kong, sustainability practices still centre around resource recovery. Optimality is still far from reach if waste management is not coupled with waste minimisation practices. And in construction, this means minimising virgin material extraction and utilisation.
Aside from the application of Green design, the use of sustainable materials should become a priority. For example, bamboo is a good resource as it is abundant in Asia and highly sustainable. The FAO report in 2007 says that 65 per cent of the world’s bamboo comes from Asia, with the majority being concentrated in China and the rest spread across Southeast Asia. Research showed that the mechanical properties of engineered bamboo products are comparable with or even surpass those of timber or engineered timber products. However, construction on a large scale cannot rely solely on bamboo because procurement is still difficult and innovation is still lacking.
It is also important to note that C&D waste is not just about solids, but also in terms of carbon footprint. Bamboo may seem a viable option, but processing it needs substantial energy expenditure, resulting in more carbon emissions. Advancement in technology might eventually solve this limitation. Until then, we still need common materials like cement, but this has to be combined with other elements to reduce virgin material extraction. Research by the Indian Institute of Science in 2009 proposes the following building materials and techniques.
Blended cements: Combining cement and complementary materials such as coal fly ash, granulated slag, silica fume and reactive rice-husk ash results in lesser C02 emissions. It was reported that substitution can go up to 40 per cent.
Stabilised mud blocks: These are made of compacted mixture of soil, sand and stabiliser. Major advantages include not involving burning, unlike the production of clay bricks; can be produced on-site and by using solid waste. The absence of burning alone should reduce energy by 70 per cent as opposed to the production of clay bricks.
Compacted fly ash blocks: These are a mixture of lime, dust, and fly ash being compacted into a high-density block. A plus point of this method is that it uses phosphor-gypsum as additives, which is an industrial waste product.
Rammed earth walls: These solid walls are made by compacting processed soil in progressive layers. From an aesthetics point of view, the finished products offer a variety of textures and finishes. Thickness and strength can also be adjusted. Environmentally speaking, these walls production also requires low energy and utilises waste material.
Secondary materials should be used to minimise waste. The list above presents just a few examples of the many alternatives. What should be noted is that the substitution must not have higher energy consumption and carbon footprint than the use of virgin material.
Also read: Sustainable Material and Waste Management
Building Information Modelling
The argument thus far is that recycling and reusing are not enough; and that there has to be a way to avoid waste generation. Another way to achieve this is by the use of technology that aids construction from early stage so that errors, miscalculations and the mishandling of materials can be prevented.
Building Information Modelling (BIM) may be the most promising solution as it is capable of generating and managing data that supports pre-construction phase, design phase, construction phase and post-construction phase. Because BIM can simulate construction before the actual physical construction, it can reduce uncertainty and minimise errors. In terms of waste minimisation, materials can be procured and delivered in a timely manner so that waste can be avoided.
BIM connects all parties, from owner and developer to the design and construction team. Easy access to and constant exchanges of information allow for early detection of errors. With real-time testing, reviewing and revising designs, as well as enhanced collaboration, construction will be more efficient, resources are reduced, and so are energy and waste products.
BIM’s critical success factors & challenges
A survey by National Building Specification in the UK in 2016 shows BIM adoption is the highest in developed countries: Denmark at 78 per cent, Canada 67, Britain 48, Japan 46 and Czech Republic 25. In Southeast Asia, the major players are Singapore and Hong Kong. Indonesia has implemented BIM too, but not effectively, with awareness among practitioners being high at 70 per cent, but implementation in the industry was as low as 38 per cent (reported in 2016 by Indonesian Environment Researcher Association).
In Singapore, firms such as Arup Singapore and WSP have adopted BIM successfully. In Hong Kong, Aedas Limited and LWK & Partners are some of the firms that use BIM in their project design and drawing production. According to research by National University of Singapore in 2017, the critical success factors of BIM implementation in Singapore include accuracy of models, training from the management, as well as advantages and support of implementation.
Meanwhile, in a country where BIM adoption is more recent such as Indonesia, there are still many challenges. The latest research by Universitas Diponegoro in 2019 identifies some of the factors that hinder the nation to successfully implement BIM. First, it is the reluctance to adopt new system, especially from Indonesian bureaucrats, because BIM is deemed to be complex and difficult to implement. Then, competence is low in the industry, which leads to poor operations. Finally, many companies claim that they cannot bear the costs because BIM adoption requires software installation and maintenance, staff training, and overall changes in their operational systems.
From the examples above, it can be concluded that the adoption of technology to minimise construction waste also depends on financing, just like how waste treatment is determined by how much budget is available. Aid from international organisations might help developing nations practise sustainability, but the ultimate solution is for the nations themselves to increase the income level and the economy in general.
Governments play a crucial role in the policy making. For example, Singapore requires projects larger than 5,000 square metres to register their BIM e-submissions. The Hong Kong SAR government supports waste management practices with legal instruments that the construction industry must adhere to.
As for the lack of expertise, education and training are needed to increase the competence of industry players. University graduates should also be equipped with sufficient knowledge about sustainability by making it an integral part of the curriculum.
All in all, C&D waste management and minimisation is not just the responsibility of architects, engineers and constructors, but also the governments and the society at large. It is more than an environmental issue because of how deeply connected the issue is with other sectors, so tackling it requires intensive collaboration.
 World Development Report 2012, The World Bank
 What a Waste 2.0: A Global Snapshot of Waste Management to 2050, World Bank Group
 Global Status Report 2017: towards zero-emission, efficient, resilient building and construction sectors
 Released by Economic Drivers and Environmental Consequences (OECD)
 The Straight Times, 2019
 Source: International Solid Waste Association (as prepared by Environmental Management LLP)
 What a Waste 2.0 – Global Snapshot of Solid Waste Management to 2050 by the World Bank
 The World Bank Press Release NO: 2018/037/SURR
 Wahi, N., Joseph, C., Tawie, R. and Ikau, R. (2016). Critical Review on Construction Waste Control Practices: Legislative and Waste Management Perspective. Procedia – Social and Behavioral Sciences, 224, pp.276-283.
 Moh, Yiing Chiee and Abd Manaf, Latifah (2014) Overview of household solid waste recycling policy status and challenges in Malaysia. Resources, Conservation and Recycling, 82. pp. 50-61. ISSN 0921-3449; ESSN: 1879-0658
 Guidance on Applying the Waste Hierarchy, 2011
 Sharma, B., Gatóo, A., Bock, M. and Ramage, M. (2015). Engineered bamboo for structural applications. Construction and Building Materials, 81, pp.66-73.
 Venkatarama Reddy, B. (2009). Sustainable materials for low carbon buildings. International Journal of Low-Carbon Technologies, 4(3), pp.175-181.
 Conference Proceeding of Temu Ilmiah IPLBI 2016
 Liao, L. and Teo, E. (2017). Critical Success Factors for Enhancing the Building Information Modelling implementation in Building Projects in Singapore. Journal of Civil Engineering and Management, 23(8), pp.1029-1044
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 Singapore BIM Guide version 2 published by Building and Construction Authority 2013
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