Waste Management for Sustainability in the Built Environment

Abstract

Wastes are unwanted, undesirable, or unusable materials. Waste is any substance discarded after primary use or may be worthless, defective, and regarded as having little or no use. A by-product and, by contrast, a joint product of relatively minor economic value. Waste management or waste disposal includes the processes and actions required to manage waste, namely preservation, recycling, and reuse from its collection point to its final disposal. Waste generated from construction sites is not supposed to constitute problems for the built environment. Sustainable construction waste management is becoming a reality because of increased awareness and education to reduce/recycle/reuse wastes, provision of collection and recycling points, and improved techniques for reusing construction materials. This chapter will focus on reducing, reusing, recycling, and recovery efforts or the 4R waste management approach for a sustainable built environment. This chapter also describes waste management practices, their benefits, and the effect of prefabricated constructions and mass customization design approaches on waste reduction or control.

1. Introduction

1.1 Construction waste management

Waste generation in the construction industry is considered to be one of the major contributors to total waste production, generating around 36% of the total solid waste, resulting in 2.5–3.5 billion tonnes each year around the world [1]. The enormous generation of Construction Waste (CW) presents a significant challenge to the sustainability of the construction industry, the country’s economy at large, and environmental sustainability worldwide. Waste in construction is identified in different ways in the literature. For instance, [2] defined waste as a material that should be moved from where it was generated to another location due to damage, excess, and non-use. These materials may not be used specifically due to non-compliance with given specifications or simply because they are by-products of the construction process. This definition is limited to waste materials that are generated during the construction process [3]. However, it provides a more detailed definition including waste that can be generated from other construction stages/phases. They stated that construction site waste comes in the form of building debris, rubble, earth, concrete, steel, timber, and mixed site clearance materials, which may be various construction activities such as land excavation, site clearing, demolition exercises, and building renovation activities. This simply means that waste materials are made of inert and organic materials. Notably, these definitions refer only to material waste; however, [4] defined construction waste as material, labor, and machinery waste, which may lead to loss of time, cost, and quality. The definitions above prove that construction projects have different types of waste. One of the purpose of this paper is to identify construction waste components and to know which type is going to be focused upon and why.

Various types of waste are generated throughout the construction project. The amount and classification of these wastes depend on different issues, such as the nature and the stage of the construction project and the methods of construction. Solid waste from construction projects often comprises a mixture of inert and non-inert materials. These inert materials such as such as concrete, bricks, ceramics, plaster, asphalt, aggregate, rock or rubble, and soil, are components that rarely participate in chemical reactions under normal circumstances. The ferrous and non-ferrous metal, timber, plastic, glass, paper, cardboard, wallboard, and other organic materials are examples of non-inert materials that readily engage in chemical reactions.

2. The 4R approaches to improving construction waste management practices

The construction industry is flourishing worldwide at a great pace, driven by population growth, urbanization, and increased need for dwellings, business sites, and commercial spaces. The built environment, which is also a major component of the construction industry, is not left out in this trend. The resultant effect means that there is a serious challenge to implement sustainable waste management in the construction industry. Waste management, according to [5], comprises all the activities involved in collecting, transporting, processing, managing, monitoring, and disposing of various waste materials. Observing sustainability is very crucial in waste disposal so that the waste materials can be managed in an efficient manner instead of dumping them in landfills. It also entails curtailing the generation and disposal of materials in a way that averts adverse environmental effects [6]. The authors further explained that waste can be reduced, and if generated, possible reuse and recycling are engaged while disposal comes as a last option.

Sustainable waste management comprises collecting waste materials, transporting waste materials, valorization, and disposal of various waste materials in a manner that does not harm the environment or affect human health negatively or future generations [7]. Sustainable waste management includes all processes involved in the organization of waste management, from production to the final treatment. It also involves the transition from the traditional make-use-dispose traditional practices to a more circular economy. In a circular economy, waste returns to the production cycle, either as new raw materials, energy, or a new product [8]. The major goal of sustainable waste management is to reduce the amount of natural resources consumed, reuse the materials taken from nature as much as possible, and create as minimal waste as possible. It is not only the duty of waste management contractors and companies to ensure sustainable collection and management of construction wastes responsibly but also individuals doing their own DIY projects at home. It is also the responsibility of all building stakeholders to maintain sustainability for the benefit of the built environment as well as future generations [9]. Without a concerted effort to collect, recycle, and dispose of waste properly, there is a real danger to the environment that will eventually spill over to people, vegetation, and wildlife. Ecological and environmental conditions around cities are put under pressure as there is an increase in transportation distances, and protection and quality of life diminish, which results in a decline of sustainable commitment and behavior of users. Rondinel-Oviedo [2] noted that resource reduction strategies and integrated waste management in close collaboration with construction stakeholders, urban planners, and infrastructure developers are the basis for achieving environmental improvement in the built environment.

A well-functioning sustainable waste management system should incorporate feedback loops, focus on processes, embody adaptability, and divert wastes from the disposal. Sustainable waste management, therefore, helps improve the air and water quality by creating jobs and improving waste management methods, which lessen the impact of human activities on the environment. It also helps to improve overall human life by reducing food wastage keeping environmental costs at a minimum while preventing poor human health conditions. The role of education can also bring about a positive behavioral change toward sustainable waste management, especially in the built environment.

More than half of the world’s population have little or no access to good waste collection and disposal systems. Illegal waste dump grounds are over 40% of global waste [10]. The lack of waste facilities is not the only major challenge, as inadequate information contributes to sustainable waste collection and safe disposal. It starts with proper education of people on waste reduction, reusing, recycling, and waste recovery efforts, which can be simply known as the 4R approach. Through proper education and information campaigns, people will respond to changes in behavior and attitudes toward waste management. This will enhance awareness of the benefits of waste reduction, segregation, collection, reusing, and recycling, thus becoming a collective and conscious effort.

Reducing simply means efforts made to decrease or lessen the amount of waste produced within the built environment. Waste reduction, according to [4], is using less material and energy to minimize waste generation and preserve natural resources. Waste reduction includes reusing products such as plastic and glass containers and purchasing more durable products. Eyeglasses, clothing, and other used materials can be donated to help reduce the amount of material manufactured overall. Pollution as well as waste can also be reduced by purchasing products that replace hazardous materials with biodegradable ingredients [11]. Waste reduction can lead to several environmental benefits, greater efficiency in manufacturing and utilization of goods, leading to less energy consumption. More natural resources are preserved, less solid waste ends up in landfills, while products using less hazardous materials are reused due to waste reduction. Waste reduction also contributes to economic savings because fewer materials and less energy are used when adopting waste-reduction processes. Instead of engaging in the traditional cradle-to-grave procedure, a cradle-to-cradle approach is incorporated where products are not used for a finite time. Instead of disposing of materials or the components of material after a single use, these materials can be converted to other useful purposes [12]. This can also be known as a flow of materials from one phase or use to another. Such an approach can also be adopted in the construction industry or between organizations that may or may not be related cooperatively. For instance, a cotton manufacturer can send some unwanted scraps to an upholsterer, who uses the scraps as stuffing in chairs. When the life span of the chair is reached, the materials can be returned to the manufacturer, who reuses the parts with endurance. The damaged upholstery, created initially using non-hazardous materials, is sold to a local farmer who composts it. This way, waste-disposal costs are reduced as fewer materials end up as waste, while money is also saved through reduced purchasing. Several ways of practicing waste reduction in the construction environment include reusing products.

Waste reusing is the practice of using a waste material over and over again in its current form. Waste reusing entails taking old or unwanted items that one might otherwise have thrown away and finding a new use for them [13]. Waste reuse, according to [11], is the action or practice of using a waste item to fulfill a different function such as reusing file folders instead of disposing of them after one use or reusing water bottles for storing other liquids after using them to store water. Another example of waste reuse includes using both sides of paper in photocopying to minimize waste and giving out materials that may seem useless, but that another party may find valuable. Waste reuse ensures that waste does not have to be further treated or processed before it is put to good use while recycling/composting requires processing to take place to turn waste material into usable resources. The essence of reuse is to preserve some or all of the energy and materials that went into making such items [3]. Construction stakeholders should embrace the practice of reuse by finding alternate uses for waste items rather than disposing of them. Some common examples of waste reuse include donating used household items like books, magazines, clothing, kitchen wares, etc., to people who may use them for other services. It may also include using empty food containers to store leftovers or reusing plastic grocery sacks as trash containers. Another example is a chair manufacturer who may have no internal use for the scrap upholstery left over after recycling, and this simply means that there will be more durable parts of the used chairs. A good arrangement between the carpenter and the local farmer will allow the scraps to be used once again, benefiting the farmer by adding to his compost.

Waste recycling involves recovering and reprocessing waste materials for use in new products. It includes collecting waste materials, processing or manufacturing into new products, and purchasing those products [1]. Waste materials that can be recycled are usually made from iron and steel scrap, aluminum cans, glass bottles, paper, wood, and plastics. Most waste products can be recycled and reused as substitutes for raw materials from scarce natural resources such as fossil fuel, natural gas, coal, trees, and other mineral ores. Recycling can help to reduce the rate at which solid wastes are deposited in landfills. Recycling also reduces the amount of air, water, and land pollution resulting from waste disposal.

Waste recovery is the extraction of waste materials or energy from waste for further use or processing, including, but not limited to, making materials into compost [13]. Waste recovery, according to [12], is the process of using wastes as an input material to create valuable products as new outputs. Waste recovery is an operation where some waste materials serve some useful purpose by replacing other materials that would otherwise have been used to fulfill a particular function. The benefit of waste recovery is that it reduces the amount of waste generated in the built environment, thus reducing the need for landfill space, and also helps to optimize the values created from waste. Waste recovery often delays the process of using raw materials to produce new materials. Materials obtained from municipal solid waste, construction, demolition, commercial, and industrial waste are often used to recover resources for producing new materials. For instance, plastic, paper, aluminum, glass, and metal can be found in waste and retrieved for use and other purposes.

Waste recovery is part of a circular economy in which the extraction of both natural resources and waste generation is reduced to the barest minimum. It also involves waste materials and products being redesigned more sustainably for durability, reuse, reparability, remanufacturing, and recycling. Lifecycle analysis (LCA) can be used to compare the resource recovery potential of different treatment technologies [3]. Resource recovery can be employed in the process of sanitation, which includes processes and activities of recovering resources trapped in wastewater and human excreta (urine and feces). The term “toilet resources” has come into use recently, which may include organic matter, energy and water, and nutrients such as nitrogen and phosphorus [14]. This concept is also referred to as ecological sanitation. Separation of liquid wastes such as keeping urine separate from feces (as in urine diversion toilets) and keeping greywater and blackwater separate can help make resource recovery simpler. A sustainable waste management plan should always include recovery as a priority strategy for its treatment. However, sometimes it may not be feasible to recover and recycle discarded materials, which are considered non-recoverable waste, and they mostly end up in dumpsites and landfills. It is imperative for countries to introduce regulations on these types of waste, which will require companies to supervise disposal operations by adopting the necessary measures to protect human health and the built environment (Figure 1).

Figure 1.

The 4R approaches to waste management hierarchy.

2.1 Sustainable waste management practices in the built environment: economic and social benefits

Man-made structures, features, and facilities are collectively known as the built environment. Built environment, according to [9], are man-made surroundings that provide settings for human activities, which ranges from buildings, parks, green space, and neighborhoods. The built environment includes the buildings, the distribution systems that provide water, electricity, and the roads, and it also consists of the bridges and the transportation systems that people use to get from place to place [1]. The construction and the use of facilities within the built environment by the people tend to generate a lot of waste materials. The provision of skip bins, collection containers, and recycling centers dramatically influences how much people and their communities recycle and reuse or dispose of construction waste properly. Finding a sustainable way to manage or dispose of these wastes is paramount to maintaining a healthy environment.

This is why contractors and recycling specialists must put their heads together to minimize construction waste. However, the authors [7] noted that the general awareness of reducing dumping has recently increased as about 35% of construction and demolition waste (CDW) goes to dumpsites and landfills. Construction wastes comprise many toxic materials such as lead, asbestos, and other dangerous substances that can find their way into the soil, groundwater, and the air we breathe. Also, in recent times, stakeholders in the construction industry have recognized that reusing building components and materials in the making or erecting structures is sustainable, which can save costs, too. Most construction materials consist of wood, sticks, steel, concrete, and rubble, which can be compacted and reused for construction purposes. Demolition is carefully considered if renovation can be carried out. Sustainable waste management is a set of practices and strategies used to reduce the negative environmental impacts of waste disposal. It includes reducing waste generated, reusing and recycling materials, and composting organic waste. Sustainable waste management practices can help the built environment to create economic and social benefits through the following ways.

2.1.1 Reducing expenditure

One of the main benefits of sustainable waste management is the reduction of expenditure. Money-saving opportunities arise from reducing the waste created and reusing or recycling materials. Firms, companies, and business owners can save money by reducing the amount of packaging they use and recycling materials like cardboard and plastic. Companies can also save money on maintenance and operating costs using fewer resources, such as energy and water.

2.1.2 Improvement of environmental health

Reducing pollution and dangerous chemicals is one of the major aims of sustainable waste management. Reusing materials can reduce the need for new resources, which helps protect the environment from the impacts of resource extraction. Sustainable waste management can also improve air and water quality, improving communities’ health.

2.1.3 Economic growth

Sustainable waste management can create economic growth comprising more waste management opportunities, increased tax revenue for local governments, and support for local businesses. Companies focusing on waste reduction, reuse, and recycling can create more jobs in their communities, and local governments can receive more tax revenue from businesses reducing their waste. Businesses that adopt sustainable waste management practices can support local businesses by buying locally produced and recycled products.

2.1.4 Better community collaboration

Sustainable waste management practices can also increase community engagement. Communities can become more engaged with waste management practices by providing better access to recycling and composting resources, educating citizens about sustainable practices, and encouraging participation in green initiatives.

2.1.5 Improved resource efficiency

Reusing and re-purposing materials through sustainable waste management practices can help to reduce the need for new resources and also help conserve materials. Recycling materials like paper, plastic, and metal can also help save resources including reducing the need for new resources or raw materials.

2.1.6 Promotes better health and safety

Sustainable waste management can also improve health and safety. Reducing the number of toxic chemicals in the environment can help reduce the risks of health problems. Lowering the amount of waste generated will also reduce the number of pests and disease-carrying organisms. Improving air and water quality could also lead to improved health and safety of people within the built environment.

2.1.7 Promotes positive social impacts

Sustainable waste management can also have positive social impacts. These impacts include increased civic pride, improved quality of life, and more equal distribution of resources. Improving air and water quality can improve the quality of life for citizens. More efficient use of resources would lead to more equal distribution of resources, which can help reduce poverty.

2.1.8 Economic rewards

Sustainable waste management practices within the built environment can also lead to financial benefits. These benefits include tax breaks and incentives, increased access to grants, and reduced insurance premiums. Businesses that reduce their waste can qualify for tax breaks and incentives from local governments. Also, businesses that focus on sustainable waste management can access grants to help cover the costs of sustainable practices (Figure 2).

Figure 2.

Economic and social benefits of sustainable waste management.

2.2 Constraints to an effective construction waste management

Construction waste management is considered the most important item for all construction stakeholders worldwide. Creating novel solutions and understanding different sustainable approaches will be required to attain effective and sustainable construction waste management. Increasing the recycling rate for non-hazardous waste materials can be an ambitious target in certain countries, which could contribute to the improvement in the economic and environmental sectors. Sharing best practices, techniques, and barriers among decision-makers and stakeholders is paramount for developing new policy and strategic frameworks for sustainable waste management. There are so many barriers that hinder the effective implementation of waste management in construction projects, and some of them include the following:

2.2.1 Weak institutional framework

In most countries, several institutions are involved in waste management, often leading to many institutions reneging on their responsibility for waste management, thinking that another institution would tackle the problem, as there is usually confusion about who is responsible. A weak institutional framework is particularly a major challenge to effective, sustainable waste management in most developing countries, where the institutional arrangements for waste management are weak.

2.2.2 Poor law enforcement

Most developed countries have a good history of safeguarding the environment by ensuring proper construction of waste management systems with appropriate legislation. However, enacting and enforcing waste management legislation is still a major challenge, especially in developing countries including Nigeria. The non-enforcement and non-compliance with laws governing construction waste management have significantly contributed to poor construction waste management in many developing countries of the world.

2.2.3 Weak regulation

The regulation of the environment, including construction waste management, is essential to ensuring good environmental governance. However, weak enforcement of environmental regulations in many countries allows construction firms to flout regulations on construction waste management without sanctions.

2.2.4 Weak technological advancement

When concentrations for greenhouse gas reduction, landfill minimization, and land reclamation are involved, construction waste management technology choices in many countries are increasingly becoming very complicated. This is also partly because the construction waste management sector is evolving into a specialized industry with high technological standards. Thus, engagement with the sector will require in-depth experience, thorough research, and engineering expertise.

2.2.5 Poor human resources

Human resource is essential for effective waste management, especially the daily operations of construction waste management. Many countries do not have the human resources with the requisite expertise required to function in a construction waste management system effectively.

2.2.6 Insufficient attention paid to construction waste management

Stakeholders in the construction industry usually focus more on completing the project within budget, expected time, and to the desired quality, to the detriment of the waste that emanates from the construction activities. This has given a bad image to the construction industry, as the improper disposal of construction waste results in far-reaching environmental consequences.

2.2.7 Lack of fundamental data on construction waste management

Sound waste management requires reliable data on generation rates and composition of the waste. In many developing countries like Nigeria, there is no fundamental data on construction waste management that will inform effective planning for sustainable construction waste management. However, in most developed countries, the available data on construction waste management are woefully inadequate to help in any construction waste planning or management.

3. The effect of implementation of prefabricated constructions and mass customization design approach on waste reduction or control

Prefabrication is a construction process where the bulk of construction activities are shifted from the building site to a remote factory or workshop [15]. Prefabrication involves the process where housing components are manufactured off-site in a factory setting with precise specifications from the architect or engineer. These prefabricated components are then transported to the building site where they are quickly assembled into a cohesive structure. It is an efficient and eco-friendly method of building structures faster while still maintaining quality control because it creates buildings with superior structural integrity in a fraction of the time and cost of traditional building methods. Mass customization is the process of manufacturing customized and personalized building designs for a specific group of people [16]. Mass customization also involves designating adaptable personalized housing units for a specific group of people [17]. Mass customization entails offering housing units that meet the demands of individual customers but which still can be produced on an industrial and larger scale. Prefabrication construction and mass customization is a rapidly growing manufacturing process that has been embraced by architects, engineers, and construction managers in recent times. However, the continuous development of the construction industry has drastically increased the amount of waste, which not only causes enormous waste of resources but endangers the environment and well-being of building occupants. Thus, the reduction and treatment of construction waste have become a major topic of concern worldwide. Prefabricated constructions and mass customization design approaches can help in waste reduction or control through the following:

1. Adoption of deconstruction approaches while reducing the need for demolition: Prefabricated buildings and mass customization designs help to eliminate waste generated from demolition activities. Prefabricated housing units are good examples of recycling, re-purposing, and reusing building materials for different purposes in construction. They are flexible, adaptable, and essentially built to be un-built. Many prefabricated buildings are geared toward permanent construction, especially where many businesses still rely on the temporary use of housing units. Relocatable buildings are brought on-site when expansion space is needed quickly, or as swing space to house refugees, students, patients, or employees during a remodel or emergency situation. When extra space is no longer needed, the housing units are removed from the grounds and re-purposed for reuse. Unlike the traditional construction approach, the housing units are not demolished, and materials are not deposited at dumpsites or landfills after a single use. Instead, the used housing units are refreshed so they can be reworked and used in future projects, further decreasing the need for additional raw materials and energy to create something new from scratch.

2. Promotion of waste control through recycling approaches: Prefabricated constructions and mass customization design approaches boast impressive sustainability credentials due to their focus on recycling materials throughout their entire lifecycle. Some of these includes the sourcing of recycled steel frames and utilizing sustainable building practices during assembly processes such as rainwater harvesting and greywater reuse systems that reduce water waste on-site significantly compared to traditional builds. Also, many builders are reusing building materials for other purposes after a single use instead of disposing of them or discarding them completely as waste products. Without increasing project costs, many manufacturers are adopting the use of green roofs and living walls, which can provide additional insulation while simultaneously creating habitats for local wildlife all.

3. Promotion of less material waste of construction projects: With off-site construction, prefabricated and mass produced units are assembled in a controlled manufacturing environment. This reduces material waste associated with poor weather conditions and construction site theft. Also, excess materials from one project can be re-purposed or used on other buildings coming through the manufacturing plant instead of being discarded at the end of a project, as they may be on a conventional construction site. Following the off-site manufacturing process, the prefabricated units are delivered to the construction site up to 80 percent complete. Reducing on-site work significantly limits construction waste generated on the project site, where it is often difficult to gather, retain, protect, and re-purpose building materials.

4. Offering substantial savings over lifetime: Prefabricated buildings and mass customization units are mostly designed to be easily dismantled and reused at the end of their lifecycle, helping to reduce waste that may be sent to dumpsites and landfills. Thus, contributing to circular economies that promote long-term sustainability goals for the environment. The efficiency of prefabricated buildings and mass customization units can also offer substantial savings over their lifetime due to their net zero design principles. By adopting the use of renewable energy sources like solar power and geothermal heating/cooling systems, these buildings require less energy from outside sources, resulting in lower utility bills for building occupants over time.

4. Conclusion

Sustainable waste management practices in the built environment can provide a wide range of benefits to companies, businesses, and communities. These benefits include reducing expenditure, improving environmental health, economic growth, and so on. By adopting sustainable waste management practices in and around the built environment, private houses, homes, companies, businesses, and communities can save money, protect the environment, and create economic and social benefits. Adopting and implementing sustainable waste management practices can help ensure that all occupants of the built environment are more sustainable and resilient now and in the future.

Conflict of interest

The authors declare no conflict of interest.

Notes/thanks/other declarations

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