Urban Sustainability in Construction: A Comparative Review of Waste Management Practices in Developed Nations

Abstract

The development of the construction industry in Hong Kong and the UK has long played a vital role in economic development, advanced or otherwise, but has also brought formidable environmental challenges, particularly in terms of the huge volume of waste generated. This review paper puts under scrutiny the environmental management practices and green materials and technologies adoption in the construction industries of two developed regions, Hong Kong and the UK, the main objective being to compare their approaches to construction waste management and assess the level to which they have adopted sustainable practices. This review recognizes construction waste as a major contributor to environmental degradation and indicates the on-site waste reduction according to waste hierarchy as adopted by both regions. Major findings are that effective environmental management practices, such as resource optimization, waste minimization, and pollution prevention, are also enforced through legislation and fiscal policies. The use of eco-concrete, plastic wood, and recycled steel, together with high-tech roofs and solar panels, shows a move toward sustainable and energy-saving building that is taking root more and more. This paper highlights the need for policies and innovation in promoting sustainable building. Future studies should look into the green techs’ long-term performance, cross-area policy spread, and how digital tools help maximize waste and create sustainably.

1. Introduction

The construction industry has a major reputation for its important input to the global economy growth of any nation. As far as economics is concerned, precedent research revealed a positive relationship between building sector growth and the GDP of the nation, which is a typical measure of the output of the country used to describe its economic status [1,2,3]. Reports state that on average 5–7% of the GDP accounts for the building sector in the majority of the countries [4]. Development wise, the building sector puts up fundamental structures housing property, public and private infrastructures, and transport infrastructure, which are important to social economic development and the well-being of states. With a role in driving modern civilization, the size of the global building market has been steadily increasing, with more than double the building development expected to take place by the year 2030 compared to 2020 [1].

Meanwhile, the resurgence in the growth of the construction industry is destined to have a substantial impact on the environment. According to [5], the building sector is responsible for 50% of landfilled solid waste, 50% of climate change, 40% of freshwater contamination, and 23% of air pollution. The construction industry has also been claimed to extract more than 400 million tons of raw materials per year, which directly correlates to the production of bulk construction waste [6]. Indeed, the environmental effect of the construction industry extends throughout the life cycle of construction activities, from initial off-site construction materials production to on-site activity during the construction period, as well as the building use-phase until the ultimate dismantling stage [7].

For instance, while physical facilities are being built on-site, heavy machinery and trucks cause traffic problems and emit dust. Stormwater also pollutes water when it runs over loose soil on the building site, but the most significant issue is the production of construction waste [8]. Additionally, the fabrication of building materials and components (off-site construction) requires a significant quantity of virgin non-renewable material inputs as well as energy consumption throughout the production processes. Furthermore, demolition becomes necessary after the constructed structure’s lifespan is over. As a result, a significant quantity of construction waste, both inert and non-inert, is produced during the demolition stage [9,10]. Because the majority of building waste is treated and deposited at landfills, it occupies precious land space [8]. For non-inert construction waste, the other alternatives for treatment include incineration and biological treatment [6]. The problems with biological treatment and incineration involve the management of secondary waste products and the possible concerns of harmful gas emissions. All these direct impacts from construction operations could have an extended impact on the population and its environment.

Since the wave of environmental problems, such as global warming and resource depletion, has prevailed over the previous decade, mounting pressure now faces the construction industry. Commitment to better environmental performance by the construction industry in its operations and products serves to define an investment in the environment [11]. Due to general increased environmental concerns, environmental management strategies are very high in monitoring construction activities [12]. Environmental management practices, in general, relate to the interventions used by organizations to mitigate the environmental implications of their activities. Environmental management methods are founded on the principles of effective use of natural resources, waste reduction, energy and water efficiency, and pollution prevention and mitigation measures [7,13]. Process-based or product-based environmental management methods are possible [11]. The former is concerned with reducing the environmental effect of operations, such as noise control and contaminated water treatment. The latter focuses on greener materials, such as the use of recycled and recovered materials in buildings.

Indeed, the government sector exerts the most effective pressure through the execution of laws and regulations [6,12,13,14]. The Environmental Protection Agency (EPA) has delegated power to states to execute specific statutory provisions; thus, a construction developer must check with federal, state, and local authorities before beginning a building project. Otherwise, a breach may result in a civil penalty, which may include a fine and imprisonment. In addition to regulatory requirements, there are also sponsored programs for the construction sector to adopt as a voluntary code of conduct. The Building Research Establishment Environmental Assessment Method (BREEAM) and the Civil Engineering Environmental Quality Assessment and Award Scheme (CEEQUAL) are two examples of voluntary codes that serve as rating systems for building environmental performance. Projects or construction organizations that subscribe to and receive awards under these schemes may boost the reputation of the firm and assist in its long-term development [6].

In addition, within corporate strategies, green materials and green technology are factors that are gaining more and more momentum. Green building, green construction, and sustainable building describe the built environment using green materials and green technology. This idea refers to both the physical structure and the use of resource- and environment-friendly procedures throughout the life cycle of the building, starting from the stages of planning up to the design, construction, operation, maintenance, renovation, and demolition [15]. Since the promotion of the Sustainable Development Goals (SDGs), green building concepts have already been developed in the global construction industry. It is already in the developed countries where there is development in green material technologies to produce building elements or projects more environmentally sound [6,16]. One of the forces is the increasing money put by business angels into green technology, looking at the profit and growth of businesses connected with alternative energy sources like wind and solar power, as well as low-carbon technologies [17].

The growing market for green building technology is also being observed in many developed nations as a result of financial institutions’ support for green buildings. Given the prospects in the green building market and the alignment with legislative trends, banks are becoming more committed to providing companies pursuing environmentally friendly projects with easier access to financing [17]. For a project to be referred to as a “green building”, a third-party certification from an accredited organization that verifies the green features is required. In the US, the Building Environmental Standards (BESt) verified by the US Green Building Council is the dominant system, while the Building Owners and Managers Association is the dominant system in Canada [15]. With financial assistance, building firms are more engaged in using green technology techniques to supplement or enhance their projects. This, in turn, contributes to environmentally conscious practices in the construction industry, which stimulates innovation that offsets implementation costs and improves the competitiveness of contractors in terms of developing sustainable strategies to adapt to an unpredictable competitive environment [17].

In spite of the increasing literature on green building and environmental management, not much comparative analysis has been undertaken to see the specific operationalization results of how these concepts are implemented by the policies of developed countries and the adoption of technology in real construction practices. This review article focuses on Hong Kong (HK) and the UK due to their distinct yet complementary approaches to urban sustainability and construction waste management. Where the UK has a rather matured and well regulated market with established circular economic principles, stringent waste reduction requirements, and high levels of policy innovation in sustainable construction, all rooted strongly within its extensive legislative framework, HK provides the antithesis as a high-density Asian city with space constraints on landfill areas where intense environmental imperatives have had to play upon a rapid building development scenario working to pressurize and hence drive its waste strategies towards the technological and adaptive. By comparing these two urban centers, which are different in terms of geography and culture, this review tries to find the best practices that can be applied, policy innovations, and implementation challenges. These would help make the efforts toward sustainable construction and waste reduction more effective in urban areas, when applied globally.

2. Methodology

A systematic review of the literature was carried out, using major academic data sources, on environmental management practice and the adoption of green materials and technologies within the construction industry of developed economies. Emphases were placed on the examination of these issues in the contexts of the UK and Hong Kong. The databases and repositories searched were Scopus, Web of Science, ScienceDirect, and SpringerLink, supplemented by Google Scholar. The search was confined to literature published between 2010 and 2024 to ensure the capture of both the development and the current state of implementations. Boolean operators and keywords used for this search were as follows: “construction industry” and “environmental management practices”, “green materials” or “sustainable materials” and “construction”, “Hong Kong” or “UK” and “waste management in construction”, “sustainable construction” and “policy” or “regulations”, “green technology” and “developed countries”, “EMS” or “environmental management system” and “construction projects”. Articles and reports were included if they discussed the following: environmental management practices or green material utilization in the construction sector, developed countries (with a focus on Hong Kong and the UK), content based on regulations, implementation strategies, barriers, or case studies regarding environmental management in construction. The source had to be from peer-reviewed journal articles, government reports, conference proceedings, magazines, or institutional white papers published in English. Literature was excluded based on the following: articles focused solely on developing countries without reference to developed nations, publications that did not address environmental sustainability in construction, duplicate articles across databases, and studies lacking empirical data or practical insights. The initial search provided over 250 articles. Titles and abstracts were reviewed for relevance, following which 115 articles were retained. After a full-text review based on the inclusion and exclusion criteria, 64 articles and reports constituted the final set that was selected for detailed analysis (Figure 1).

3. Environmental Management Practices in Construction Industry

Consistent with the growing awareness of the need for environmental protection, environmental management practices are increasingly incorporated in most industries, including the construction sector. These practices are implemented due to regulatory compliance pressure, the expense of environmental technology, and client or stakeholder aspirations for environmental performance [12,18,19,20,21]. The subsequent subsections of this chapter examine the status and environmental issues of the construction sector in Hong Kong and the UK, as well as the management practices used to address these challenges.

Environmental management practices are divided into three categories based on the mode or level of practice: operational, tactical, and strategic. Operational level practices relate to daily organizational decisions and actions, such as waste reduction, resource reduction, and resource allocation mechanisms on the building site. Tactical level practices, on the other hand, are inherently tied to supply chain management, design and development, and environmental performance recognition, with decisions made on these elements affecting intermediate deployment. Furthermore, strategic level practices encompass policies, programs, and environmental awareness, where strategic choices may have a long-term impact on an organization’s path [18,19].

In the long term, they will help an enterprise be more environmentally compliant, become more operationally efficient, and build strength against future risks. It will also enhance corporate images and stake-holder trust, leading to competitive advantages in the market that calls for more sustainability. While the up-front costs of investment in environmental technologies and systems could be high, cost–benefit analyses have demonstrated that the long-term savings are much more often substantially greater than the initial costs of material usage and waste disposal and energy consumed and probable government fines as well. Moreover, proactive adoption of the environmental initiative will trigger corresponding innovations for enrolling for green finance or government subsidies.

3.1. Status, Policy, and Environmental Management Practices in Hong Kong

3.1.1. Status and Issues in the Construction Sector of Hong Kong

HK has seen large growth in infrastructure, especially with new railways and old district areas. The major impetus for growth in the construction industry is private housing and public infrastructure; real value quadrupled in private housing and doubled in public infrastructure from 2009 to 2019. This marks a return from the 9.2% drop in 2020 due to COVID-19, spurred on by more than USD 100 billion government investment in homes, railways, roads, and hospitals. This industry accounts for about 10% of the total working population in HK, providing employment to over 300,000 people [22,23,24,25]. The building sector produces the largest portion of solid waste, it is high in energy consumption, and it depletes natural resources. The major environmental challenge is at the level of waste produced by construction. In 2000 the daily generation was 37,690 tons, and by 2020 it stood at 56,622 tons/day, which was a 17% rise from 2019. This is mostly inert material, at about 80%, and 20% non-inert waste-like plastic, wood, and packaging [8,22,26,27].

Construction waste in HK goes through management by way of landfilling, direct reuse, or the provision to public fill reception facilities. Non-inert waste delivered to landfills is categorized as construction and demolition (C&D) waste. This was the sector that, in 2001, contributed 38% to total landfill waste; the value dropped to 26% by 2010 and further to 3418 tons/day in 2020 due to increased disposal charges and government incentives promoting waste reduction [19,20,27,28,29]. There are three landfills, namely South-East New Territories (SENT), North-East New Territories (NENT), and West New Territories (WENT), that receive construction and demolition waste, with the highest volume per day going to SENT. The growth has mainly been in construction waste, which until recently was disposed of in landfills, but a shift has been seen to reduce landfill disposal and increase reuse and deliveries to fill facilities. However, the overall growth in construction waste emphasizes the urgency of much stronger preventive measures and continually more sustainable practices [18,28].

Reported by [8], the HK government is spending HKD 200 annually on waste disposal. Not only does this incur a hefty expense for landfill disposal, but it also consumes about 3500 m³ of important landfill space every day. Because HK is a small territory with limited land and a very big population, there is no room for additional landfills to accommodate the growing waste loads. In HK, the landfills were constructed in the key development areas of the New Territories Landfills located in residential neighborhoods. The landfill space will be fully utilized within a few years and has been on the plans. Land-filling is not only consuming precious land resources, but it is also generating contaminated leachate, which is hazardous to the environment. Furthermore, the incinerators in HK are primarily used for treating non-inert waste; hazardous pollutants are an emission that has gained significant concern [8]. In return, construction waste, specifically inert materials, was used to fill reclamation sites. This means that the control which can be exerted is towards making landfills receive less solid waste.

3.1.2. Governmental Policy of Hong Kong

The development sector plays a core function in the fast growth of cities in HK. However, it also leads to a key part of environmental damage especially through waste within construction wastage. The government of HK has set several environmental policies in order to manage these issues. These included the Ordinance of Environmental Waste alongside an Ordinance of Control in Air Pollution and an Ordinance of Impact Assessment in Environment—all under the management of the Protection Department Environment. To help solve the problems resulting from waste within construction, the government has developed several policies which are listed in

Table 1. Chronology of government policy for construction waste management in Hong Kong.

Regulation	Year	Policy	Ref.
Waste Disposal Ordinance	1980	Legislation waste generation in construction sites. Framework for managing onsite waste from generation to disposal. Prohibit use of any premises as waste disposal area unless permitted by Director of Environmental Protection. Amendment in 2003 to accommodate construction waste disposal charging scheme and waste crime.	[11]
10-Year Plan	1989	Aim to minimize construction waste and other environmental pollution issues.	[11]
Green Manager Scheme	1994	Appoint Green Managers from all governmental departments to look after green-housekeeping-related matters. Focus on water and energy saving.	[11]
Waste Disposal Regulations	1995	Introduced charge payment for disposal of wastes (chemical waste and construction solid waste) at landfills.	[11]
Waste Disposal (Designated Waste Disposal Facility) Regulation	1996	Ensure the upkeep of orderly conduct within places used for waste disposal activities. Prevent the evasion of service charges of waste disposal.	[11]
Waste Reduction Framework Plan	1998	Reduce, reuse, and recycling aspects (materials management).Milestones include extend landfill useful life, reduce quantity of waste, conserve non-renewable materials, increase recycling practices, persuade the public on the true cost of waste management, and encourage efficient on-site and off-site waste management operation.	[11]
Landfill Charging Scheme	1999	Based on principles of “Polluter Pays” and “User Pays”.	[11]
“Construct for Excellence” report	2001	Responsible for implementation: Construction industry Review Committee and the Departments of Buildings, Lands, and Planning. Promote the use of recycled and green building materials in the design and construction operation to reduce construction waste.	[19]
Joint Practice Note (JPN)	2001	JPN1 (2001) and JPN2 (2007) were published on reducing construction waste. They provide exemption of site coverage or gross floor area (GFA) calculation for builders to increase the use rate of prefabricated external walls. The 2011 revision introduce an overall cap of 10% GFA exemptions for qualified features.	[19]
Practical Note on Recycled Aggregate	2003	To eliminate the uncertainty of using recycled aggregates under the guidelines for recycling construction waste, the use of reusable aggregates should be promoted and standards and guidelines for their use should be developed. Technical guidelines apply to concrete for both prescribed and planned mixes.	[19]
Waste Management Plan and Pay for Safety and Environment Scheme	2003	This is highlighted in the circular “Construction Site Waste Management” from the Environment, Transport and Labour Office.	[19]
Recycling Pilot Plant	2004	Established in Tuen Mun, inert waste is processed into recycled aggregates for road construction and as raw materials for the production of asphalt and small concrete structures. Between 2004 and 2006, public projects began using recycled aggregates.	[19]
Trip Ticket System (TTS)	2004	The system was introduced in 1999 and expanded in 2004 to combat illegal waste disposal. Destinations and routes are tracked and monitored.	[19]
Construction Waste Disposal Charging Scheme	2005	Promote the sorting, reduction, and resource utilization of construction waste. Two external sorting facilities (Tuen Mun and Tseung Kwan O) have been set up.	[19]
Best Practice Guide	2009	Published by the Hong Kong Construction Association for reference by frontline management teams when dealing with environmental issues (including site waste management).	[19]

.

A major initiative has been the Waste Management Plan (WMP), which has been made a mandatory requirement for all construction projects since 2003. Even though some of the industry players had earlier criticized the WMP due to its vague requirements and the way it was encumbering productivity, other parties acknowledged its value in reducing environmental harm. Challenges included limited space for on-site recycling and additional demands for monthly monitoring [20,21]. To reduce landfill waste, the government introduced a landfill charging scheme based on the “Polluter Pays Principle”, requiring them to pay increasing fees for landfill use. Additionally, a two-tier strategy was implemented: administrative measures limit C&D waste landfilling to no more than 20% inert material, and economic incentives encourage people to sort and reuse their waste [21,22]. Inert construction waste accounts for about 80% of all generated wastes and is sent to public fill sites for land reclamation; the non-inert type goes to the landfills. This preserves natural resources and has an overall positive effect on the landfill life extension. The composition of mixed wastes leads to inefficient separation and ultimately more waste being disposed of in the landfills. The green building is further supported by government through reduced land rental cost. The “Ecopark” offers to plant the recyclers with affordable land and facilities, hence providing opportunities for innovation and circular economy practices within the sector [10,22].

3.1.3. Environmental Management Practices in Hong Kong

Figure 2 illustrates the typical construction waste management practices in HK, which can be categorized into seven key areas: legislative controls, public filling, landfill area control, on-site sorting, environmental management system (EMS) implementation, the Waste Reduction Framework Plan (WRFP), and recycling schemes. Effective management of such construction requires on-site sorting of material, prescribed in the policy for Waste Management on Construction Sites. Contractors are required to make provisions for sorting waste on these sites into categories such as metals, plastics, paper, chemicals, and excavated materials before disposal. Among them, the facility at Tseung Kwan O also assists in sorting [8,10,12,19,20,22,23,29]. In addition to other things, it makes provisions for waste disposal to have a legislative framework for the regulation of construction waste from its generation to where it should be disposed of. This entails prohibition of unauthorized disposal of waste as well as conditions to be met by waste treatment facilities. Inert waste, like concrete, sand, and earth, goes to the public fill sites that the Civil Engineering Department runs, with 29,220 tons delivered in 1999. Non-inert waste—wood, packaging, and organic material—goes to the specified dumps.

The companies use EMS with performance auditing, life cycle assessment, and product standards. The EMS comprises five main components: policy, planning, implementation, inspection, and review. The construction waste hierarchy has it at the base in the attempt to conserve landfill space, decrease health hazards, and decrease project cost [8,19]. This is the waste-wise hierarchy that treats recycling concrete into the processing of new material technologies. The practice of sorting and recycling on-site has been established on very few building sites because it is expensive and there is no place and time demand for it. Generally, the site management team focuses on the financial and quality objectives of the project and may overlook the environmental concerns of the project. Such recycling would most probably be carried out with high-value metals and not with low-value packaging materials [8,29,30,31].

Figure 2. Construction waste management in Hong Kong ([7,32,33]; Icon from Flaticon Basic License CC3.0 (Creative Commons)).

Figure 2. Construction waste management in Hong Kong ([7,32,33]; Icon from Flaticon Basic License CC3.0 (Creative Commons)).

In addition to the challenges, the Demonstration Scheme (DEMOS) was launched by the government to promote new recycling technologies. Incentives are provided for setting up recycling plants. Intermediate sorting facilities have also been established. These can play an important role in increasing recycling potential and reducing landfill disposal [19,30]. Environmental management practices depend on professionalism and awareness. Since 1996, the ISO 14000 EMS standard has been in place as a voluntary tool that gives impetus to companies willing to enhance their environmental performance. The Education Bureau Hong Kong Productivity Council and Hong Kong Quality Assurance Agency respond to the need for education and, jointly with other professional bodies, offer training courses for top-level construction personnel [8,19].

This section illustrates case studies for the recycling of construction and demolition (C&D) waste in Hong Kong. Two off-site sorting facilities are available. The first is Tseung Kwan O Area 137, sorting C&D waste and receiving waste if more than 50% is inert. The construction waste is charged at HKD 175 per ton under the Construction Waste Disposal Charging Scheme. Upon arrival, the waste is weighed first to begin preliminary sorting to eliminate bulk non-inert materials like metal and wood. Then, more advanced sorting technologies will further separate the materials wherein inert waste material will be crushed and used in fillings. Material which is non-inert is disposed of in a landfill. The off-site sorting is very important. It is particularly important for the urban construction site because of the inadequate space available for sorting. On-site recycling is more feasible for civil projects like tunnels and roads due to larger site areas. The on-site recycling systems are fully included in the Kai Tak Airport redevelopment and Tseung Kwan O–Lam Tin Tunnel projects. For example, large rocks from tunneling were crushed for backfilling. Aggregates are the main recycled product, but they must meet size requirements to avoid ground settlement issues. Despite increasing landfill fees encouraging on-site recycling, many contractors still prefer off-site disposal due to space constraints, even at higher costs [10,12,19,29].

3.2. Status, Policy and Environmental Management Practices in the UK

3.2.1. Status and Issues in the Construction Sector of the UK

The construction industry in the UK is one of the fastest developing industries, accounting for 8.2% of the country’s GDP and employing around 2.1 million people [6]. Its critical contribution to social and economic development affected 70% of the produced wealth in the UK [21]. The construction industry, on the other hand, makes some of the biggest environmental problems worse, such as using a lot resources and producing a lot of waste [6,21]. According to the Department for Environment, Food, and Rural Affairs (DEFRA), around 380 million tons of resources are extracted for the construction industry annually [31]. The construction waste management status in the UK has not been very encouraging. In 2004, construction waste accounted for around 32% of all waste produced. In contrast to the most current statistics, data from 2010 to 2018, the construction industry remains the leading contributor to total UK waste and its share has increased to 62% [26,32]. A similar trend was observed in the case of England. Hobbs [31] reported that construction waste, including demolition and renovation waste, contributed around 33% of all waste generated. Recent statistical data in year 2010–2018 indicated the share of construction waste has increased to 64%, with mineral waste from C&D and soil aggregates accounting for the most [31].

According to the Building Research Establishment (BRE), the majority of construction and demolition (C&D) waste in the UK is composed of concrete (59%) along with inert materials (21%), metals (10%), wood (7%), plasterboard (1%), and insulation (1%). Further, C&D waste contains hazardous waste, with hazardous waste accounting for 32% of all construction waste in England and Wales [31]. Because they must be disposed of in specifically approved landfills with incineration being the only alternative option, the disposal of these hazardous waste products presents a particular difficulty [8]. Concern also arises due to the limited storage options and most hazardous waste disposal facilities being situated far away, which results in rising waste disposal costs and a direct contribution to carbon impact. Besides that, C&D waste has been identified as the primary component of fly-tipped waste. According to Hobbs [31], there have been almost 60,000 reported instances of waste crime involving wastes from construction projects since 2007, costing the government a great deal of money to clean up. Moreover, construction is responsible for 47% of CO₂ emissions [22]. Improving the environmental performance of the construction sector is therefore essential for sustainable development since it is one of the critical industries that drives economic growth.

3.2.2. Governmental Policy of the UK

The Strategy for Sustainable Construction of the UK government promotes improved sustainability in the procurement, design, and operation of built assets. A key objective has been to eliminate construction waste sent to landfills, supported by interim targets aimed at significantly reducing landfilled construction waste. This, therefore, implies that the Construction Resources and Waste (CRW) Roadmap reinforced a reduction in material use and waste generation under construction, renovation, and deconstruction activities, which aligned with the Waste Strategy for England, focusing on halving both non-aggregate waste production and the amount of landfilled waste produced through reuse and recycling [28,32].

The UK uses laws, economic tools, and willing codes to help meet sustainability goals. Waste rules must follow the EU waste order. This means waste prevention comes first, then reuse, recycling, and last of all landfills [14]. Big policies include Site Waste Management Plans, the Landfill Tax, and others like them too. The Landfill Tax falls under the ‘Polluter Pays’ principles and is more of a financial penalty that discourages waste disposal. Even though the tax escalator has been implemented to reduce landfill usage, its unintended consequence has been the escalation of illegal dumping, popularly known as fly-tipping. The government has to come up with a huge annual allocation to be able to address this issue. A law has been passed granting local authorities’ power to monitor as well as report illegal dumpers through a centralized database. More legal measures mean heavy fines and even imprisonment of the offenders. Introduced in 2002, the Aggregates Levy charges a payment on all extracted and imported aggregates. The increase is meant to contribute to recycling and to reduce the environmental impacts of quarrying. From 1.6 GBP/ton it rose to 2 GBP/ton in 2009. Even though aggregate use per construction unit dropped by 40% between 2002 and 2010, it again increased by 2% between 2010 and 2018, which shows the long-term impact of the levy.

The Site Waste Management Plan (SWMP) Regulations were introduced to further divert waste from landfills. Initially launched as a voluntary initiative by the Department for Business, Enterprise and Regulatory Reform (BERR), the SWMP later became mandatory for construction projects exceeding a specified value. It supports a range of UK and EU environmental policies, including the Environmental Protection Act and the Waste Management (Duty of Care) Regulations. Early planning to address waste issues, as outlined in the SWMPs, must be documented in the project scope, value, and responsible personnel. Normally, contractors are responsible for developing the SWMP. However, it may be undertaken by the subcontractors or specialist waste contractors. The SWMP promotes documentation, tracking, and revision as needed. Improving waste categorization, it reduces fly-tipping incidents. Aiding the plan, Building Research Establishment (BRE) created SMART waste, a tool which helps the contractors by recording data on the type and volume of waste. These digital tools will help in monitoring compliance as well as to create audits and baselines for future projects [14,33].

Table 2. Construction waste management tools such as the device for onsite waste planning, forecasting, and tracking.

Construction Waste Management Tool	Developer Description	Ref.
SMARTWaste	Collects and organizes data on the types and quantities of waste generated on construction sites. Helps create site-specific waste management plans that can inform future waste control strategies.	[31]
Net Waste Tool	Estimates the amount of waste that will be generated during construction activities, aiding in planning and management.	[31]
BreMap	Assists waste producers and users in finding the nearest recycling centers, reclamation facilities, and landfill sites, and it sources for locally reclaimed and recycled materials.	[14]
Webfill	An online marketplace designed to promote the reuse of construction waste by facilitating the exchange of surplus materials.	[14]
SWMP Tracker	A digital tool for compiling and analyzing data from Site Waste Management Plans (SWMPs).	[34]
ConstructCLEAR	Integrates and simplifies processes for managing SWMPs, carbon reporting, waste procurement, and ensuring regulatory compliance.	[34]

shows other tools for waste management within the UK construction industry, beginning with on-site sorting to digital tracking systems.

Some construction wastes are hazardous and, therefore, must be accordingly disposed of under EU regulations, they should be segregated from other waste streams. The preference is recycling, then landfill, and, lastly, incineration. A waste treatment facility was constructed on Teesside at the Middlesbrough Works of ICI to handle hazardous liquid waste—preventing environmental pollution [6]. The UK government has put in place economic measures alongside waste regulations to try to achieve a closed-loop production chain. It encourages waste reduction programs that will cost the business 4% of their annual revenue, though the potential savings are 1% as compared with paying landfill taxes. In the years 2005–2008, such sums as GBP 284 million were allocated to the organizations that took part in the Business Resource Efficiency and Waste (BREW) program—more than 65% of funds for waste management. The UK government supports sustainability with rating and labeling systems, also for BREEAM and CEEQUAL (

Table 3. Information about the Building Research Establishment Environmental Assessment Method (BREEAM) and the Civil Engineering Environmental Quality Assessment and Award Scheme (CEEQUAL) certification scheme developed by BRE.

Building Research Establishment Environmental Assessment Method (BREEAM)	Civil Engineering Environmental Quality Assessment and Award Scheme (CEEQUAL)	Ref.
Certification scheme for environmental assessment of building (local spatial planning projects and infrastructure projects)	Improvement of sustainability in public works and civil engineering projects via self-evaluation and rewards.	[36,37,38,39]
Often used building sustainability performance measures in the UK since its introduction in 1990.	Launched in 2015 with the support of industry organizations.	[36,37]
Ten categories of environmental criteria for sustainability assessment.	Twelve categories of environmental criteria for sustainability assessment.	[36,38]
A range of schemes for assessment that cover different requirements of building types.	A range of awards for projects involved in assessment: whole project award, client and design award, construction only award, etc.	[36,38]
The total score is a sum of various category scores that are weighted to achieve a pass (30%), good (45%), very good (55%), excellent (70%), and exceptional (85%) rating.	Pass (30%), good (40%), very good (60%), and excellent (75%) are the grades of reward. Give incentives to clients or developers to improve upon best practices.	[36,39]
Assessment is conducted independently and credible by government.	Assessment and award process involves project assessor and a verifier.	[36,38]

) [35]. Since 2008, BREEAM has certified the environmental performance of new buildings. Since 2015, CEEQUAL has certified the environmental performance of civil engineering projects. This helps evaluate sustainability in other sectors as a certification program meeting regulation on different levels while decreasing the environmental impact and improving compliance with regulations [6,34]. Legislation and regulation applied in the UK and/or England for construction waste management is shown in

Table 4. Legislation and regulation applied in the UK and/or England for construction waste management.

Policy	Remark	Effect	Ref.
Producer Responsibility Obligations (Packaging Waste) Regulations	For construction industry with GBP 2 million or more of turnover and handle 50 tons of packaging waste per year. Companies obliged to recover packaging waste.	The company collaborates with product manufacturers and supply chains to implement recyclable/returnable packaging as a means to reduce waste.	[13,23,31]
Landfill tax	Tax for active waste is 32 GBP/ton (2008) increased to 48 GBP/ton (2010). Tax for inactive waste is 2.5 GBP/ton (2008).	Impose considerable costs for industry that produce waste and use waste management contractors. Develop the culture of recycling and recovering onsite waste.	[13,23,31]
Aggregates Levy	1.95 GBP/ton (2008).	Improved financial incentive for secondary and recycled aggregates. More purchase consideration and increased on-site reuse. A higher standard of supply for secondary and recycled aggregates used in high-value projects.	[13,23,31]
Hazardous Waste (England and Wales) Regulations 2005	Requirement for identification and classification of hazardous waste. Pre-treatment of hazardous waste before landfill, particularly in situ treatment. Company needs to register site with Environment Agency if the activities producing 200 kg or more of hazardous waste per year.	An increase in the cost of hazardous waste disposal from C&D waste.	[13,23,31]
Waste Strategy for England 2007 by Defra	A vision to reduce waste production across the supply chain, promote close loop industry through reuse and recycling, and improve economics of reuse and recycling industry. Mission to halve landfilled construction wastes (including excavation component), requirement of construction client to include strategy is contractual for measurement and improvement in construction project in value GBP 1 million by 2009 and achieve waste-neutral construction.	Culture of joint working between government and industry. Client emphasizes enhanced resource efficiency. The market for reclaimed and recycled materials expanded.	[13,23,31]
Sustainable Construction Strategy 2007 by BERR	Aim to establish a joint government and industry strategy towards sustainable industry Consultation of the targets for England Waste Strategy. Targets to zero net waste at construction site level by 2015, zero waste to landfill by 2020, and halve onsite construction waste quantity.	Manufacturers consider resource efficiency within lifecycles. Tackle waste through integrated supply chains. Specification of resource efficiency by designers or architects.	[13,23,31]
Site Waste Management Plans (SWMPs)	Compulsory from April 2008 for projects over GBP 300,000.	Effective management of on-site waste through appropriate planning and monitoring. Observed ongoing reduction in fly-tipping incidents.	[13,23,31]
Code for Sustainable Homes (CSH)	For house builders to meet environmental standards. Rating for all new homes commenced from May 2008. Voluntary codes.		[13,23,31]

.

3.2.3. Environmental Management Practices in the UK

In line with the 2030 Agenda for Sustainable Development, recycling and carbon emission targets are immensely ambitious for the UK government, particularly for the construction industry. Because of the environmental pressures of C&D waste, waste management practices derive guidance from the EU waste hierarchy with respect to waste prevention. The waste management guidelines of WRAP are centered around design approaches such as reuse and recovery, off-site construction, material optimization, waste-effective procurement, and flexible demolition [23]. Among other forces, the SMART-Waste online platform was created to raise knowledge levels and set benchmarks for construction waste management [13]. Results find that the current efforts have been more geared to manage the existing waste through recycling, reuse, and recovery than waste prevention. Most of the recycling waste from construction and demolition in the UK is recycled, and the remaining is disposed to landfill sites [40]. The overall reprocessing rate of demolition waste is noted at 85% to 95% [39], showing good trends but indicating the need for more waste prevention, as per the waste hierarchy. Environmental performance is evaluated through sustainability ratings like BREEAM and CEEQUAL in various areas ranging from carbon emissions to materials and waste and waste reusability among others, thus pushing for more sustainable building practices in other ways. But the focus of the industry is over cost rather than sustainability and intractable supply chains work as additional obstacles [13,21,41]. The state of research challenges of sustainable construction strategies is shown in Figure 3.

The design–build project delivery system offers an alternative to the traditional approach, where the designer and contractor are separate entities. In the design–build method, all project team members collaborate from the start, addressing cost, scheduling, and constructability challenges. Relevant stakeholders, including contractors, contribute insights during the design phase, providing innovative ideas before finalizing the design [42,43,44]. Research by [42,43,44,45,46,47] found that design–build projects lead to greener construction through energy and resource savings, driven by reduced coordination gaps and improved communication between parties.

3.2.4. Proposing Environmental Management Practice

To sum up the previous discussions, environmental management practices in the construction industry of the two studied developed nations fall into two categories: mandatory and voluntary. The mandatory category comprises obligatory management and assessments of construction activities such as the EIA Ordinance in HK and SWMP Regulation in the UK. On the other hand, the voluntary category may commonly be coupled with market-oriented incentives, such as CEEQUAL, implemented by the construction industry in the UK and the EMS certification system implemented by the construction industry in Hong Kong. Government policy deems to have an important role to play in influencing voluntary actions and legislating mandatory requirements.

Although a range of management techniques and skills have been developed in the past to aid in improving environmental performance from the implementation of construction projects, these techniques do not appear to be being implemented effectively as a result of fragmentation and a lack of coordination among various construction participants [13,21]. This is realistic where different project stakeholders, such as clients, consultants, contractors, and subcontractors, have varying degrees of involvement in different project phases. Typically, individuals’ parties concentrate on their respective professions. As a suggestion, a previous study [48] stated that framework for a sustainability performance checklist was put forward in response to this issue to assist practitioners adopting sustainable building practices at different project implementation phases. All stakeholders may use the sustainable performance checklist as a tool to evaluate the sustainability of the projects they are involved in at various phases, including conception, design, construction, operation, and destruction. By doing this, project stakeholders may access similar knowledge and information on the sustainability performance of the project and collaborate to improve project performance [49].

4. Green Materials for Construction

Some of the green building materials prevalent in developed countries are discussed in the sections that follow in this chapter. In this paper, “green materials” are defined as those that meet at least one of the following criteria: (1) a long shelf life; (2) non-toxicity; (3) recycled content; (4) resource conservation; and (5) production from locally available renewable resources.

4.1. Recycled Plastic Lumber

Recycled plastic lumber, developed since the 1980s, is a sustainable building material made from plastic scrap and post-consumer plastic waste. Pioneering research by the Federal University of Rio de Janeiro’s Institution of Macromolecules contributed to its development. Plastic lumber comes in two forms: composite plastic lumber (a mix of polymers and natural fibers) and wood-like plastic lumber (made solely from plastics) [10,49]. Common materials for plastic lumber include high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), and low-density polyethylene (LDPE), often sourced from plastic bottles and cartons. The manufacturing process involves cleaning, shredding, grounding, melting, and adding UV stabilizers and pigments. The plastic is then molded into various shapes, including decks, benches, and parking stops [10,49].

Plastic lumber offers several advantages over wood, including resistance to water, weathering, mold, and pests, with a longer lifespan. Although initial costs can be higher, it requires low maintenance and replacement. Wood–plastic composites combine plastic with sawdust to reduce raw material costs. Additionally, fiber-reinforced plastic lumber, made with glass fibers, offers stronger characteristics but at a higher cost [10]. Recycled plastic lumber is an environmentally friendly alternative to traditional wood, reducing plastic waste and mitigating deforestation, contributing to sustainability and climate change prevention.

4.2. Eco-Concrete

C&D waste is the construction industry’s largest environmental burden. Concrete can now be made from C&D waste or other recyclable materials, known as green concrete, which uses byproducts like fly ash from coal power plants to replace coarse aggregates. This substitution improves strength, durability, and permeability, reducing early failure risks [16]. The Holcim Group has successfully developed eco-concrete, made with washed copper slag to replace 70% of sand and recovered aggregates from demolition debris to replace natural coarse aggregates. eco-concrete is used in non-structural components like bike pathways and pedestrian walkways [10]. In terms of performance, Grade 30 eco-concrete has been shown to match conventional concrete in workability, slump loss, and strength. Holcim is partnering with the Housing and Development Board (HDB) on a pilot project to showcase eco-concrete’s strength and durability in real-world applications [8]. The green concrete market in Europe is growing due to government policies encouraging eco-friendly products and tax incentives. The European Commission’s 2011 Construction Products Regulation ensures accurate information on sustainable materials, while Dubai Municipality started a campaign in 2015 to require green concrete in new projects [16].

4.3. Recovered Steel

Steel is a primary structural material in construction, widely used in multi-story industrial applications and non-residential buildings, representing about 70% of the market. Steel plays a key role in the circular economy by reducing waste and enabling recycling without losing its properties. Structural components like beams, columns, and non-structural elements such as cladding panels and stairs can be recovered and reused with minimal processing [10]. Steel recycling and reuse rates in the UK were reported at 91% and 5%, respectively, in 2012. The high recycling rates are driven by favorable market conditions and financial incentives. Steel construction waste, including rebar, heavy structural sections, and light steels, shows high recycling potential, with steel scrap from concrete being used to fabricate reinforcing bars [44,50]. Although steel has high recycling and reuse rates, 4% of demolition steel, mainly piles, was not collected for recycling or reuse, often being landfilled. Further efforts are needed to increase steel reuse, which offers greater environmental benefits than recycling, particularly in reducing GHG emissions. Reusing steel lowers the energy required for processing recycled materials and reduces the need for virgin materials [10].

5. Green Materials Technologies

Along with increasing awareness of the environmental effect of human activities, sustainable development has always been stressed throughout sectors, with the construction industry being no exception. Green technology is becoming a more desirable component in every project development to make the built environment and operations more energy efficient and sustainable. The following sections examine numerous green material technologies present in the construction industry with more favourable environmental and carbon footprint impacts than their conventional counterparts.

Table 5. Brief information on the green roof system and Building Integrated Photovoltaic (BIPV) technology.

Technology	Green Roof	Building Integrated Photovoltaic (BIPV)	Ref.
Functionality	Minimize heat flow that enhances indoor thermal comfort, reducing the energy demand for space cooling in a building and achieving energy efficient design.	Develop building surfaces as active solar collectors to supply clean, safe, economical, and decentralized power.	[17,51,52,53,54,55]
Types	Extensive green roof Semi-Intensive green roof Intensive green roof	Two major types of solar cells that make up the array of interconnecting cells of BIPV: inorganic silicon semiconductors and inorganic nanocrystalline salts deposited as thin films on a substrate. Various types of building components for BIPV, like roofs, facades, and skylights.	[17,51,52,53,54,55]
Example Project	The Solaire, New York Villa Mairea, Finland Monastery of La Tourette, France Rockefeller Center in New York	Terrace in Battery Park City, New York AstroPower’s Headquarters, Newark Delaware The Solaire, New York	[17,51,52,53,54,55]
Pros (Main)	Rainfall runoff reduction. Aesthetic benefit. Reduce surface heat flux.	Energy production Weather protection Noise protection Material savings Thermal insulation Daylight modulation	[17,51,52,53,54,55]
Cons	Considerable cost to install and maintain the system.	Power efficiency. Design lack of standardization that restricts implementation in few countries.	[17,51,52,53,54,55]

provides an overview of the green material technologies in developed countries.

5.1. Green Roof

Green roof technology is the use of vegetation applied at the rooftop to increase thermal comfort and decrease energy consumption [56]. This technology was initially adopted in Germany. The U.S. is one of the countries that later embraced the technology. Buildings are the most common place to find evidence of this technology. It is set up over sturdy surfaces in the building, composed of vegetation, nutrient mediums, irrigation, and drainage layers. The types are extensive, semi-intensive, and intensive. These green roof systems reduce the energy demand for cooling by acting as a buffer for heat flow through the roof. A pilot study in Toronto has demonstrated reductions in summer heat transfer by 70% to 90% and in winter by 10% to 30%, and it also protected the roof membranes from thermal stress and ageing by 57% due to runoff water [57]. Previous studies confirmed the additional benefits that it offers, which include reduced surface heat, improved aesthetics, and stormwater control. Despite the high capital and maintenance costs that are involved, and which do vary with the type of roof, green roofs are able to offer long-term benefits for society, the environment, and the economy. As the consciousness of sustainability develops, green roofs are getting more and more acceptance as a future trend in building design [54,55,56]. The benefits of the green roof system are summarized in

Table 6. Benefits of green roof system.

Benefit	Description	Ref.
Environmental Benefit	Act as natural air filtration. Act as carbon sink and oxygen source. Control and reduce sound reflection. Reduce ambient temperature by 0.3–3 degrees C compared to conventional roof. Shield against acid rain and UV rays.	[55,58]
Economic Benefit	Reduce energy consumption by shade, insulation, evaporation, and an increase in thermal mass. Enhance the energy efficiency of structures. In response to a rise in temperature, a green roof is less susceptible to contraction than other construction materials. Provide thermal comfort by absorbing shortwave radiation and cooling the ambient temperature, therefore mitigating the urban heat island effect that is prevalent in cities and towns. The thermal insulation provided by a green roof against UV radiation oscillations and diurnal stress extends the roof’s lifespan.	[55,58]
Social Benefit	Places for recreation and rest. Great for human health and wellbeing (psychological impact) Enhance living environment. Offer environment for rare or imperiled species.	[55,58]

.

5.2. Building Integrated Photovoltaic (BIPV)

Production of energy is the most emerging aspect of photovoltaic technology. It has been costly and not as developed, so there were not many applications in the past. The current state is such that recent technical leaps have broadened its applications [53]. Among these, Building Integrated Photovoltaic (BIPV) systems are major advances. Essentially, a BIPV system integrates photovoltaic technology with building materials, such as roofing and façade systems. This turns the surface of the building into an electricity-generating element. Giving decentralized clean energy, it also improves the aesthetic and functional values of a building [53]. The BIPV system may be composed of roof tiles interconnected to each other, with the major ones incorporating crystalline silicon or thin-film technologies. Crystalline silicon provides higher efficiency [59]. The choice of the type between these two major alternatives depends on the application, type of building, and demands of the customer. Owing to easy integration, less material consumption, and flexibility in design, the thin-film photovoltaic system is gaining acceptance among all new forms of markets. PV modules currently come with several newer options for architects—opaque or semi-transparent, flexible or rigid, and multicolor, among others. BIPV modules shall take over the role of conventional building components such as tiles, glazing, and skylights. They shall merge energy generation with insulation and also how it looks. The products range from solar tiles and foils to Building Applied Photovoltaics (BAPVs). This evolution places BIPV as a transformative approach to sustainable building design. Figure 4 displayed the wide array of BIPV technologies that are now in use on the market [60].

BIPV systems generate other building benefits outside energy production, which includes protection against weather and noise, daylight control, thermal insulation, and savings material. An example is thin-film PV panels that are integrated into transparent glazing at New York Stillwell Avenue Station to balance energy generation with daylighting and, at the same time, to offer shelter. This installation supported a 259 kWp solar power plant. The systems could be grid-tied or off-grid, where grid-tied systems are currently predominant because they can use the utility grid as a virtual battery storage system and support peak demand.

Table 7. Case studies of BIPV applications in a developed country.

Case Study	Residential Building in Battery Park City, New York.	AstroPower Headquarters—A Solar Cell Manufacturer in Newark, Delaware.	Ref.
BIPV Technology	Front façade equipped with an 11 kW_p BIPV solar system. A total of 11 rows of standard solar modules mounted horizontally and tilted towards the sun in front of the brick façade building. (Passive solar heating.) Semi-transparent canopy PV module at the entrance of the building. Landscaped flat roof.	A 30 kW_p BIP façade covering front face of building. A 310 kW PowerGuard system covering the roof of manufacturing plant of building. Insulated glass PV technology as sunshades in façade that create a large skylight above the entrance of lobby.	[52,54,61]
Functionality	BIPV façade supplying 5% of building base electricity consumption. Passive solar system contributes the dominant portion of green power supply for the building.	Supply the total electricity consumption of entire administrative offices. PowerGuard systems provide thermal insulation that help protect roofing membrane from harsh UV radiation. Blue tinted insulation glass window offers optimum light within a working climate.	[52,54,61]
Structural design	By using TEDLAR encapsulation technology, the PV laminates made into custom shape to adapt to building dimensions in standard glass. The modules integrated into cassette façade system, which is an external cladding system to provide a skin or layer that eases installation.	BIPV façade constructed from aluminum façade system with custom sized TEDLAR PV laminates (glass) mounted into supporting structure. Ballasted PowerGuard System that enables mechanical attachment to the structure without any penetration, enhancing roof warranties. Integrate the multi-crystalline solar cells into PV modules through glazing technology to form a uniform blue appearance.	[52,54,61]

shows two more buildings where the technology of BIPV systems was applied in the building design. The BIPV is functionally versatile. Its main limitation is efficiency. The BIPV module performance depends mainly on design and engineering. Major standardization of photovoltaic components was not available till now to meet international and national codes. In Europe, many custom-designed modules are certified under the International Electrotechnical Commission; however, these suffer at the time of U.S. adoption because first they have to pass a long term of domestic certification requirements [52]. This has held back wider implementation in the U.S., comparative to Europe. Major challenges have been experienced in the development and integration of BIPV as a multifunctional and sustainable building technology [54].

6. Future Policy Direction

To promote sustainable building practices, future policy should address the structural and operational gaps identified in the current environmental management systems (EMSs) of developed nations, such as Hong Kong and the UK. An enhancement recommendation in the form of mandatory performance-based regulations for the use of green technologies and recycled materials with standardized environmental performance indicators capable of benchmarking projects and companies across all borders will be most welcome. Because small- and medium-sized enterprises (SMEs) are more likely to be financially burdened in the implementation of greener technologies, government financial incentives and technical training education programs should be more specific and more direct in support for SMEs for the understanding and application of green construction materials, such as eco-concrete and recycled steel [62,63]. More importantly, the policy frameworks should require sharing data and technology innovation findings and best practices among the academic sector, government departments, non-government organizations, and industrial partners. This will build institutional capacity and set an environment that makes normal sustainable ways across the whole chain. Lastly, seeing and doing something about transparency and reporting should be made stronger through digital tech-like building information modeling (BIM) and material tracking systems that allow wastage and resource usage to be monitored in real time. Such digital integration makes traceability better and promotes a culture of always getting better [64].

7. Conclusions

This paper reviews the sustainable construction practices and technology adoption under the purview of green technology in two developed areas, i.e., Hong Kong and the UK, which have intense construction waste problems due to rapid urban development. This study uses Prisma, a qualitative comparative analysis by reviewing peer papers, policies, and case strategy documents to assess the strategies for waste management, Environmental Management Systems (EMSs), and integration of green building technologies. Results show that both regions prioritize on-site waste reduction through EMSs, adhering to the waste hierarchy and emphasizing resource efficiency, energy and water conservation, and pollution control. Environmental management has both mandatory regulations and voluntary industry-led schemes. Legislative measures, such as Members’ Bills and fiscal incentives, are seen to play a significant role in promotion. In addition, both contexts show increasing integration of recycled and eco-friendly materials such as recycled steel, eco-concrete, and plastic timber, and green infrastructure, such as green roofs and Building Integrated Photovoltaics (BIPVs). Policy implications suggest a need for enhanced collaboration among the stakeholders and a more regulated approach. Future policies should introduce financial incentives and technical training programs to improve green technology implementation, especially among small- and medium-sized enterprises (SMEs) lacking capacity and expertise. Therefore, future work can encompass the above and constrains this paper to reject quantitative data and performance indicators, laying out regional comparisons. Small businesses face socio-economic and policy constraints that are not addressed. Sustainable practices should be validated through empirical research using performance indicators and case-based evidence.