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Environmental assessment of construction and demolition waste recycling in Bolivia: Focus on transportation distances and selective collection rates
Abstract
Construction and demolition waste (CDW) management in developing countries is a global concern. The analysis of scenarios and the implementation of life cycle assessment (LCA) support decision-makers in introducing integrated CDW management systems. This paper introduces the application of an LCA in La Paz (Bolivia), where CDW is mainly dumped in open areas. The aim of the research is to evaluate the benefits of inert CDW recycling in function of the selective collection rate, defined as the amount of
waste (%wt.) sorted at the source in relation to the total waste amount produced, and the distances from the CDW generation to the material recycling facility. The outcomes of the research suggest that increasing the selective collection rates (5% to 99%) spread the
importance of transportation distances planning since it affects the magnitude of the environmental impacts (1.05 tCO2-eq to 20.7 tCO2-eq per km traveled). Transportation limits have been found to be lower than about 40 km in order to make recycling beneficial
for all environmental impacts and for all selective collection rate, with the eutrophication potential as the limiting indicator. The theoretical analysis suggests implementing LCA with primary data and involving statistics related to the transportation of virgin
materials avoided thanks to recycling. The outcomes of the research support the implementation of CDW recycling in developing countries since it has been found that material recovery is always beneficial.
... During the demolition process, a significant emission of GHG and dust is produced in addition to large amounts of diesel that are consumed by the machinery, especially during traditional demolition (Martínez, Nuñez, and Sobaberas 2013). However, the majority of research papers highlight the transportation stage as the one with the highest negative impact on the environment (Penteado and Rosado 2016;Borghi, Pantini, and Rigamonti 2018;Ferronato et al. 2021). This is because, with the increase in transportation distances, both the GHG emissions and the consumption of fossil fuels increase. ...
... Additionally, recycling remained more beneficial to the environment than disposal as long as the transportation distances from a demolition site to a recycling facility were below 30 km (Penteado and Rosado 2016). Using the same indicators, Ferronato et al. (2021) evaluated the environmental impacts of possible CDW management in La Paz, Bolivia. Selective CDW collection and transport distances related to recycling were the focus of the study. ...
... Selective CDW collection and transport distances related to recycling were the focus of the study. The environmental impacts of transport were estimated in the range of 1.05-20.7 t CO2-eq per km, suggesting the transportation limit should be set at 40 km to make CDW recycling environmentally feasible (Ferronato et al. 2021). ...
In an effort to tackle climate change and decrease the consumption of natural resources, more and more industries worldwide are adopting circular economy principles. The construction industry is no exception; however, the implementation of these principles is beyond satisfactory levels. As a consumer of more than half of the extracted materials and a contributor to more than a third of waste, the construction industry hides great circular economy potential. In recent years, the scientific community has devoted a great effort to investigate different aspects of construction and demolition waste (CDW) management. The assessment of key aspects of sustainability, such as the economic, environmental and social aspects, were particularly studied, mainly to find the optimal management alternative that would be the least detrimental to the environment and the society. However, the available studies rarely included all three pillars of sustainability. Moreover, management alternatives that were assessed included only recycling, backfilling and disposal in most cases, leaving the treatment options that support circular economy principles such as reuse and high-quality recycling unexplored. Additionally, most of the studies performed sustainability assessments on statistical data of CDW quantities that are often unreliable and may significantly underestimate the sustainability performance. The main objective of this research was to propose a new model for the sustainability assessment of CDW management and the selection of the optimal CDW management alternative. To achieve this objective, the following specific goals were addressed: 1) setting up a unique material stock database that includes the types and quantities of materials embedded in buildings; 2) proposing possible CDW management alternatives; 3) proposing a model for estimating future quantities and composition of CDW; 4) proposing a model for assessing the sustainability performance of the proposed alternatives; 5) comparing and ranking of CDW management alternatives; 6) analysis of the ranking results and selecting the optimal CDW alternative. The model was tested in a case study for the management of CDW from residential buildings in Serbia. In this case study, three alternatives: the current CDW management (BAU), the alternative that aims to achieve the EU average CDW recovery rates (EU28(2018)) and the alternative that implements circular economy principles in CDW management practices (CE) were evaluated and ranked. Each alternative was ranked against four different decision-makers scenarios: economic, environmental, social and holistic. The model includes the integration of the existing and widely used methods: bottom-up inventory analysis and dynamic stock modelling for the estimation of the material stock and CDW quantities and composition, Cost-Benefit Analysis for sustainability assessment and Multi-Criteria Decision-Making Analysis (Analytical Hierarchy Process - AHP) for ranking of the CDW alternatives and choosing the optimal CDW management alternative. The implementation of the model in the case study for CDW management in Serbia yielded three sets of results. The first set of results was related to the creation of a unique material stock database that included the list of materials embedded in residential buildings built between 1946 and 1990 with detailed specifics (geometry and physical characteristics). Based on this, viii the total weight and the composition of the materials embedded in these buildings were calculated. The total weight of material embedded was estimated to be 714.6 million tonnes, out of which 601.1 million tonnes were embedded in single-family house (SFH) buildings and 113.5 million tonnes of materials were embedded in multi-family house (MFH) buildings. The materials with a share of over 80% belong to the mineral fraction (concrete, bricks, tiles, ceramics). The second set of results included the potential waste quantities and composition when these buildings in Serbia are renovated or demolished. Depending on the renovation alternative, the total amount of waste in the period 2021—2046 ranged between 40.2 and 41.1 million tonnes, with an average annual contribution between 1.5 and 1.6 million tonnes. The sensitivity analysis of the waste quantities showed that these quantities might range between 0.89 and 2.5 million tonnes if the demolition rate changes up to 30%, while the renovation rates do not bring significant changes to the amount of waste. The highest share of the waste stream (67%) is made up of clay and concrete-based materials. Consequently, the waste composition (waste streams) and the possible treatments of these waste streams determine the sustainability performance of three proposed CDW management alternatives for Serbia. The third set of results was related to the sustainability performance and the ranking of CDW management alternatives. The direct outputs of the Cost-Benefit Analysis (financial and economic net present value) identified cash flow balance and potential economic, environmental and social benefits to the waste operators and the society for each alternative for Serbia. The current CDW management alternative in Serbia was the worst option. The financial and the economic net present values were negative in this alternative, which implies that managing waste under this alternative will not benefit the waste operator or society. On the other hand, the CE alternative was identified as the best option, with both of these indicators positive. The ranking of alternatives with the Multi-Criteria Decision-Making Analysis resulted in the optimal CDW management alternative under different decision-making preferences. In the environmental and holistic decision-making scenarios, the CE alternative was ranked as the optimal, while the current waste management alternative was ranked as the optimal solution under the economic and social preferences. In addition, the sensitivity analysis applied to the sustainability performance revealed several critical variables such as the demolition rate, discount rates, capital and operational costs and unit prices of recovered bricks and aggregates. These are the variables that should be carefully considered when waste management strategies are planned. The case study showed that efficient CDW management practice depends on active participation and partnership of all stakeholders, from policymakers to researchers and practitioners. All these stakeholders may find the proposed model useful from different management aspects. The policymakers may use this model to evaluate the effects of the stricter implementation of the existing regulations and the promotion of new regulations such as the carbon and landfill taxes or even landfill bans for recyclable waste fractions. More advanced instruments would include reusing and recycling subsidies and the implementation of green procurement provisions in public contracts. And finally, in lack of financing for better waste management practices, carefully planned and contracted public-private partnerships may be the right answer that will, in the end, benefit all partners, the environment and the society.
Full dissertation available at: https://grafar.grf.bg.ac.rs/handle/123456789/2712
... Results showed that landfilling of wastes has a preference over the recycling option despite the economic benefits that can be gained from the recycling scenario. Ferronato et al. (2022) investigated the environmental viability of CDW recycling in Bolivia. The recycling scenario is compared to waste disposal. ...
... The possibility of this variation is confirmed by Ram et al. (2020) who reviewed many studies and indicated the different values of energy consumption, whether for diesel or electricity. However, it is worth noting that this variation has no effect on the sensitivity analysis since the relationship between these parameters and the environmental impact is linear (Ferronato et al. 2022;Pantini and Rigamonti 2020 the assumption of the range used for the sensitivity analysis yields the same conclusion (Ram et al. 2020). ...
Construction, demolition, and renovation activities generate a significant amount of waste, posing serious environmental risks. The scarcity of recycling facilities makes it difficult to implement the new legislation, which calls for producing recycled aggregates. Moreover, the lack of studies on the environmental feasibility of recycling construction and demolition waste in regions with plentiful natural resources of aggregates is a contributing factor to this scarcity. Therefore, this paper studies the environmental feasibility of establishing a construction and demolition waste (CDW) recycling plant. A case study approach compares the CDW recycling process against the traditional quarrying process for generating aggregates. The lifecycle assessment method is used for evaluating both scenarios. Contribution analysis is performed to infer the factors influencing the viability of the recycling process. Thereafter, a sensitivity analysis is conducted to determine the suitability of the proposed location for the recycling facility. As revealed by the single score, the recycling alternative has a 23% more negative environmental impact than quarrying. Nevertheless, there is a chance that the recycling process could be environmentally advantageous. Findings indicated that a total travel distance of 70 km between the demolition site and the construction site is recommended to guarantee environmental feasibility. The transportation distance is found to be the most critical element influencing the environmental feasibility of recycling CDW. The findings of this study help the decision-makers in environmental affairs to consider the influencing factors when constructing a CDW recycling plant.
... This cluster is concerned with investigating the environmental implications of CDW, which helps authorities and stakeholders make decisions about the collection, treatment, and disposal plans [89]. It incorporates sustainability, environment, waste management, and disposal keywords. ...
... From an environmental standpoint, recycled aggregates have been claimed to be sustainable in areas where natural resources are few or large distances for the transportation of virgin materials are required. As a result, it is crucial to undertake and support environmentally sound decisions for CDW management [89]. ...
Construction and demolition waste treatment has become an increasingly pressing economic, social, and environmental concern across the world. This study employs a science mapping approach to provide a thorough and systematic examination of the literature on waste management research. This study identifies the most significant journals, authors, publications, keywords, and active countries using bibliometric and scientometric analysis. The search retrieved 895 publications from the Scopus database between 2001 and 2021. The findings reveal that the annual number of publications has risen from less than 15 in 2006 to more than 100 in 2020 and 2021. The results
declare that the papers originated in 80 countries and were published in 213 journals. Review, urbanization, resource recovery, waste recycling, and environmental assessment are the top five keywords. Estimation and quantification, comprehensive analysis and assessment, environmental impacts, performance and behavior tests, management plan, diversion practices, and emerging technologies
are the key emerging research topics. To identify research gaps and propose a framework for future research studies, an in-depth qualitative analysis is performed. This study serves as a multi disciplinary reference for researchers and practitioners to relate current study areas to future trends by presenting a broad picture of the latest research in this field.
... This paper is the result of two previous studies: the first, an LCA related to the formal MSW management system of La Paz (Ferronato et al. 2021b), and the second, focused on the evaluation of the environmental benefits obtained thanks to CDW recycling (Ferronato et al. 2021a). The research reported on this article sums up the outcomes of both investigations, comparing and critically assessing the priorities that should be considered for reducing the environmental anthropic pressure, and quantifying the environmental benefits due to recycling for both waste fractions. ...
... In particular, construction materials, fuel consumption of the transportation trucks, and the impacts of the landfill gas and leachate emission as well as the avoided impacts due to recycling were obtained by the software, which refers to the Ecoinvent 2.1 database. The complete inventory of the research related to the MSW management systems is published and available in Ferronato et al. (2021b), while the inventory related to the CDW management system is published in Ferronato et al. (2021a). Therefore, the current paper does not provide the inventory analysis conducted within the research, whereas it is focused on the comparison of two studies carried out within the same context. ...
Construction and demolition waste (CDW) and municipal solid waste (MSW) are the waste flows mostly generated at a global level. In developing countries, most of these waste streams are disposed of in open dumps. Policy-makers should be informed in which priorities should be established in order to improve the quality of the environment. The current research compares the environmental impacts generated by the MSW and CDW management system of La Paz (Bolivia). The aim is to evaluate (1) which environmental impact indicators are more important per waste flow and (2) if recycling can be considered a good option for mitigating such environmental footprint. A life cycle assessment (LCA) of the formal MSW management and the CDW mismanagement (i.e., open dumping) were conducted. The analysis of the management system (2019) is compared with future developments in recycling that counts with the support of an international cooperative project financed by the Italian cooperation. Results reported that, at a municipal level, CDW mismanagement contributes more than 60% to the freshwater aquatic ecotoxicity, which represents the most relevant impact generated by this waste stream. Recycling allows achieving avoided impacts higher than the ones produced for three of six environmental impacts, suggesting MSW and CDW recovery as an important option for preventing environmental degradation. The research is the first attempt to highlight the importance of organizing appropriate CDW management systems into an integrated waste management scheme for mitigating environmental impacts in developing cities.
... In developing countries, more than 90% of waste is either dumped illegally or burned. Moreover, unauthorised disposal of CDW is creating social, economic, and environmental issues [6,7]. Construction and demolition waste management (CDWM) is a complex and challenging task all over the world because of its nature, composition, volume, and complexity [4]. ...
Construction and demolition waste (CDW) comprises the major portion of solid waste and it is becoming a global concern due to rapid urbanisation. Construction and demolition waste management (CDWM) and circular economy (CE) are interconnected as both focus on waste prevention and resource conservation. However, without having an efficient CDWM system, CE establishment is not possible. Policies are the leverage for any national or local level action. Although there are policies and regulations on CDW, inadequate enforcement and challenges faced during implementation have made the policies dormant or unsuccessful. Hence, there is a dire need to understand various aspects and challenges involved in CDWM to develop effective polices. This study explains political, market, environmental, economic, social, local, and technical aspects of CDWM and how different regions are striving to implement CE. Best practices, pioneers in CE, major challenges faced during CE establishment, and how policies could be used to overcome the issues are discussed. A continuous improvement framework to establish CE in construction sector and a robust action plan to implement the framework at the regional level have been proposed in this study. This study will guide policy maker to develop policies that are inclusive, flexible, and dynamic to enable gradual circular transition.
Graphical Abstract
... Concerning experts' opinion, the travel distance for all materials was 50 km. Such distance relies on the studies available in the technical literature [113,114]. ...
The incorporation of waste materials in concrete is currently a practical solution to solve certain environmental concerns. Because of the property degradation of the produced concrete owing to the addition of waste materials, using pozzolans in the concrete mix can help improve the mechanical performance of recycled concrete. Therefore, in this research, the mechanical specifications of recycled concrete were evaluated at different volume fractions of recycled fine aggregates (RFA) replacing natural fine aggregates (NFA). In addition, the impact of adding colloidal nano-silica particles on the performance of conventional and recycled concretes was investigated. Various parameters comprising compressive strength, pulse velocity, splitting tensile strength, flexural strength, elastic modulus, and water absorption were carefully examined. The attained experimental results reveal that the mechanical and physical characteristics of concrete degrade with increasing the volume fraction of RFA replacing NFA. Also, increasing the weight percentage of nano-silica replacing cement up to 6% in conventional concrete and that containing RFA improves the mechanical and physical properties, the optimum percentage of which was determined as 4.5%. Furthermore, relationships were recommended for predicting the compressive, splitting tensile, and flexural strengths as well as the elastic modulus of concrete mixes by including the RFA and nano-silica replacement levels, which are in acceptable accordance with the experiments in the present study and those available in the technical literature. Finally, to investigate the environmental effects of recycled concrete with different RFA substitution levels and colloidal nano-silica incorporation, the problem-based CML 2000 and the damage-based IMPACT2002 + methods were applied using SimaPro9 software. Thus, environmental parameters such as acidification, global warming potential (GWP), eutrophication, natural resources, ecosystem quality, and human health were inspected. Subsequently, the GWP results were compared and presented using the CML 2000 and the Intergovernmental Panel on Climate Change (IPCC) approaches. To verify the estimates, all the attained results were examined against those captured from the Building for Environmental and Economic Sustainability (BEES) method. Findings show that despite the implementation of different unit measurements in different methods, the environmental effects in the CML 2000 and BEES meth-odologies are almost the same, suggesting that nano-silica is a raw material with the greatest environmental impact. Additionally, based on the life cycle comparison results of manufacturing one cubic meter of concrete with different mix designs using the damage evaluation approach, IMPACT 2002+, concrete with the RF0NS6 mix design triggered the highest damage extent in natural resource, climate change, ecosystem, and human health categories, respectively. This study fills a significant research gap from an environmental perspective by comprehensively investigating the durability and mechanical specifications of concrete containing RFA and nano-silica pozzolan. The findings presented in this research provide valuable insights into the realm of sustainable construction practices, paving the way for novel advancements in concrete technology.
... On the other hand, the environmental benefits of OFMSW treatment with BSFL can be affected by some parameters that can reduce the advantages obtained from the valorization of BSF products. First, transportation distances of the final products can increase the environmental impacts of the system (Ferronato et al. 2022). Longways for transporting BSF bioproducts can increase the environmental impacts, affecting the positive environmental results related to the impacts avoided thanks to the process. ...
Biowaste treatment with Black Soldier Fly (BSF) larvae is an alternative option for organic waste valorization. Its environmental impacts should be assessed and compared with conventional treatment options. The research aims to evaluate the treatment of organic fraction of municipal solid waste (OFMSW) with BSF larvae through a life cycle assessment (LCA). This study employed data inventories from literature and aimed to provide a wide range of production parameter values to identify the potentialities of BSF treatment in the best-case and worst-case scenarios. The SimaPro9, the database Ecoinvent3.5, and the impact assessment method IMPACT 2002+ have been employed for the analysis. A sensitivity analysis of relevant parameters was conducted, considering the avoided impacts that can be obtained thanks to the exploitation of larvae proteins for bioplastics or fishmeal production. Research findings highlight six main environmental impact indicators: respiratory inorganics (kg PM2.5-eq), ozone layer depletion (kg CFC-11-eq), terrestrial ecotoxicity (kg TEG soil), land occupation (m² organic arable), global warming (kg CO2-eq), and non-renewable energy (MJ primary). The most relevant process generating impacts is BSF breeding, followed by boiling, storage, and OFMSW treatment. The environmental performance is better when the conventional fishmeal substituted, thanks to BSF larvae production, is made from areas 10,000 km far, implementing a 100% renewable energy scenario, reducing the energy consumption by 50%, increasing the lifespan of the equipment to 15 years, and products are employed locally. The current study represents the first attempt to evaluate the global higher or lower environmental impact scenario related to OFMSW treatment through BSF larvae.
Graphical Abstract
... In Bolivia, construction and demolition waste (CDW) is disposed of in open dumping areas (Ferronato et al. 2021a). This is a typical issue in the whole Latin American region: in Brazil, performance indicators in relation to CDW management are well below those found in developed countries, although waste open dumping is banned since more than 15 years (Nunes and Mahler 2020); in Perú, there is no legislation that encourages the use of recycled concrete and final disposal is most of the time informal (Rondinel-Oviedo 2021). ...
In Bolivia, construction and demolition waste (CDW) is unmanaged. The current research implemented a CDW flow analysis and a cost assessment in the city of La Paz, aiming to compare future recycling scenarios. Lack of data is challenging; therefore, a review of 31 international studies has been conducted. Results report that the waste generation rate (WGR) of concrete residential buildings can be of about 91.9–113.3 kg m⁻² for construction and about 867.2–1064.8 kg m⁻² for demolition. In addition, positive correlation was found in national WGR with number of inhabitants and the GDP. By these results, it was estimated that about 271,051–349,418 tonnes of CDW are potentially generated yearly in La Paz, about two times more than the CDW projected by local authorities. By the scenarios analysis, it was estimated that 56.1–71.1% of the inert aggregates can be recycled. The cost of the system is estimated between 7.8 and 31.1 USD tCDW⁻¹, for a total annual cost (20 years horizon) of about 2.3–9 million USD y⁻¹ depending on the management scenario. In the best scenario, an average fee of less than 1% of the current costs of a flat in La Paz can be required, potentially affordable for the local economy. The most attractive scenario involves the source separation of recyclable materials and the hybrid organization of stationary and mobile recycling facilities. Results show that a CDW management can be implemented in La Paz to foster a circular economy in developing cities.
... Transportation distance was regarded as 50 km for all the materials. This distance was based on a survey that other researchers had also taken into account [62,63]. ...
Employing pozzolanic materials like nanosilica and silica fume as replacements for cement to produce high-strength concrete (HSC) has made investigating the mechanical features of the produced HSC and assessing impacts that producing these materials have on the environment a necessity. Therefore, this paper aimed to assess the mechanical properties, environmental impacts and life cycle of HSC containing silica fume and nanosilica where its compressive performance and microstructure were evaluated and a comparison between the effects of pozzolanic materials were compared with those of ordinary cement on environmental indices. Concrete specimens were made using seven mix designs, and different parameters, namely compressive capacity, toughness, strain at peak stress, relative energy absorption, and stress–strain relationship were evaluated. Afterward, some empirical relationships were proposed to capture concrete mechanical features. Here, silica fume at contents of 0, 8, 10, and 12 % and nanosilica at contents of 0, 1, 2, and 3 % were used as a weight replacement of cement. Further, using the atomic force microscopy (AFM) images, the microstructure of the concrete without the pozzolans and concretes with silica fume and nanosilica was studied. In addition, to investigate the environmental impacts of the concretes containing silica fume and nanosilica and conventional concrete, two methods of problem-oriented CML 2000 and damage-oriented IMPACT 2002+ were employed in SimaPro8.1 program. In this procedure, environmental parameters including acidification, eutrophication, global warming potential (GWP), human health, and ecosystem quality, and natural resources were investigated. Finally, for validation, all the obtained results were compared with those obtained using the building for environmental and economic sustainability (BEES) approach. It was found that the best weight percentages of silica fume and nanosilica replacing cement were 12 and 2 %, respectively, which led to improvement in the performance of the HSC under compression. Moreover, the proposed prediction models for the compressive performance of the HSC using empirical formulations developed for the mechanical features correlate well with the test results. Based on the CML 2000 method, the concrete containing 12 % silica fume has the greatest environmental damage in the acidification, human toxicity, and eutrophication categories, for which the corresponding indices were 6.6, 2.4, and 4.3 times those of the reference concrete. Further, by employing the damage assessment method IMPACT 2002+, the HSC with 12 % silica fume was found to have the highest damage in human health, ecosystem quality, and natural resources, for which the corresponding indices were respectively 4.7, 3.5, and 4.6 times those of the reference concrete. All the environmental indices of the HSC without the pozzolans were lower in comparison with the other concretes except for the climate change index which was higher for the HSC without the pozzolans than the other specimens.
... The outcomes of the research suggest that increasing the selective collection rates (5% to 99%) spread the importance of transportation distances: transportation limits should be lower than about 40 km in order to make recycling beneficial for all environmental impacts for all selective collection rates. It represents the current situation since the current MRF has been located about 25-30 km away from the farthest point of generation [34]. ...
This paper introduces the preliminary results of a development project focused on waste
recycling and recovery in La Paz (Bolivia). The aim is to share best practices and to present real-world challenges when implementing appropriate waste management systems in developing countries. Environmental pollution, social inequality, lack of resources, and economic discrepancies are challenges still present in the 21st century, and a global call-for-action is needed to support sustainable development. The project “LaPazRecicla”, financed by the Italian Agency for Development Cooperation, provides perspectives that are potentially useful for policy-makers, waste management practitioners, and circular economy visionaries. The article aims to present the effective contribution of the practical actions to the local municipality, and to introduce the reason for why theoretical methods were employed to support the project. The outcomes provided two main indications: on one hand, cooperation among interdisciplinary actors and financial support can give the chance of improvement, suggesting international donors should continue in this direction; on the other, political instability, lack of local technical knowledge, and the absence of planning for a long-term period makes these actions unsuitable for tangible change. Global reflections are required in order to measure the potential benefits of small-scale projects, evaluating the time needed to move towards a sustainable future in low-income countries.
... The only category that performs worst in the best-case scenario compared to landfilling scenario is freshwater ecotoxicity. Other studies evaluating the recycling of C&DW compared to other options such as waste to energy and landfilling found that recycling is a better option compared to landfilling [27,[74][75][76][77][78][79] even if it is dependent on the transport distances [25,36,80]. ...
In this study, our aim was to explore the potential energy savings obtainable from the recycling of 1 tonne of Construction and Demolition Waste (C&DW) generated in the Metropolitan City of Naples. The main fraction composing the functional unit are mixed C&DW, soil and stones, concrete, iron, steel and aluminium. The results evidence that the recycling option for the C&DW is better than landfilling as well as that the production of recycled aggregates is environmentally sustainable since the induced energy and environmental impacts are lower than the avoided energy and environmental impacts in the life cycle of recycled aggregates. This LCA study shows that the transition to the Circular Economy offers many opportunities for improving the energy and environmental performances of the construction sector in the life cycle of construction materials by means of internal recycling strategies (recycling C&DW into recycled aggregates, recycled steel, iron and aluminum) as well as external recycling by using input of other sectors (agri-food by-products) for the manufacturing of construction materials. In this way, the C&D sector also contributes to realizing the energy and bioeconomy transition by disentangling itself from fossil fuel dependence.
A novel process for the production of angular-shaped high strength fly ash aggregates from an energetic, and environmental perspective is presented in this paper and compared with the production of natural aggregates. This study is significant because there is an increasing demand for aggregates and no published research addressing the environmental impact assessment of fly ash aggregate manufacturing. For the fly ash aggregate production, all technical, energetic, and financial aspects of the production process were evaluated at the pilot-scale production plant. Whereas, for the natural aggregate production process, site-specific data is used. The environmental impacts of aggregate production processes were assessed using SimaPro and the impact analysis methodology IMPACT 2002 + from the “cradle to gate.” The results demonstrate that the production of fly ash aggregates is more desirable than natural aggregates for all environmental impact categories. Using fly ash for aggregate production avoids the impacts due to inert landfilling and extraction of basalt. The findings show that diesel and electricity are the primary sources of energy used to produce aggregates and they are principally answerable for the detrimental effects on respiratory inorganics, global warming, and non-renewable energy. A sensitivity analysis recommends that fly ash aggregate is preferable for all impact categories if the distance between the lime source and the production plant is less than 350 km. The comprehensive life cycle inventory and impact analysis aid in the decision-making process for further improvement in the production procedure of fly ash aggregates and similar life cycle assessment studies.
The concepts of circular economy and sustainability have received a lot of attention in waste management sector. Advanced technologies provide significant opportunities to improve the challenging issues in waste management process. This study highlights the most recent literature on the integration of circularity in smart waste management. It investigates the relationships between digital technologies, circular economy, and waste treatment activities. For comprehensive topic analysis, a literature review methodology was integrated with bibliometric analysis. A collection of 78 publications were reviewed and analyzed. The examination of these articles allowed the evaluation of a proposed framework based on digital solution for waste collection, segregation, leachate reuse, waste recycle, water and biogas production. It proposes a roadmap framework that incorporates machine-learning techniques for circular, sustainable and smart waste operations. The study is significant for scholars and practitioners since it presents a conceptual framework for incorporating circularity in smart waste management for developing countries to overcome traditional waste management issues.
Construction and demolition waste (CDW) is the main contributor to economic loss, environmental pollution, and health hazards if the current linear economy model of ‘take-make-consume-dispose’ is not replaced by a Circular Economy (CE) as a solution approach to maximize the use of resources and reduce waste. However, successful CE concept implementation involves strategies that trigger construction and demolition waste management (CDWM) throughout its life cycle, rather than end-of-life strategies, such as reuse and recycling. By meticulously reviewing the literature, nineteen factors that affect CDWM from CE concept implementation throughout six stages of preconstruction, procurement, construction, demolition, transportation, and end-of-life are initially identified. A hybrid fuzzy Multi-Criteria Decision-Making approach is then utilized in two main stages, including an Enhanced Fuzzy Delphi Method in stage one, to refine the identified factors according to Tehran's construction context, and a Cybernetic Parsimonious Fuzzy Analytic Hierarchy Process in stage two, to prioritize these factors. Three factors were identified during the first stage of the research methodology and added to the factors extracted from the literature. The results indicate that ‘on-site sorting, reusing, and recycling of waste materials’, ‘various procurement models’, and ‘precise implementation of waste management regulations and plans’ are the most important factors, respectively. A comprehensive list of the factors provided as part of the research findings has contributed to the body of knowledge to be used as a snapshot by researchers, while the ranking of the factors gives new insights to stakeholders on ways to manage CDW in projects.
Evidence suggests that the level of waste recycling largely depends on the effectiveness of waste recycling policy (WRP). As such, this study examined a rarely discussed, but significant perspective for promoting waste recycling, that is, the effects of residents' perceived policy effectiveness (PPE) on the effectiveness of WRP. In a quasi-experiment, residents living in Kunming central urban area served as subjects in three groups (n = 874). The primary outcome was that high level PPE could make a positive effect, while low level PPE hindered residents' recycling behavior. Subsequently, the mechanism, negative effects, and influencing factors of PPE were further explored. The main findings suggest that (i) PPE affects recycling behavior mainly through subjective norm and perceived behavioral control; (ii) PPE plays a moderating role in the trust relationship between the government and residents, and further affects the achievement of policy goal; and (iii) the perception of convenience is the important factor influencing residents’ PPE. This study made a comprehensive discussion on PPE and helped to understand the psychological causal mechanism of policy implementation and actual behavior at the micro level. In addition, it pointed out the significance of explaining the effectiveness of environmental policy from the perspective of citizens.
The planning stage plays a key role in the success of each construction project. It also pertains to projects implementedin the Natura 2000 areas that cover ca. 18% of the total land area in the EU. Permission for the realization of such a project is issued after an analysis of its environmental impact on the Natura 2000 area. An important part of the analysis undertaken as part of a habitat assessment should be the evaluation of proposed material solutions. The research has revealed that habitat assessments in Poland do not fulfill this postulation. The decision-making process is based on the legal qualification criteria, and the fundamental importance in it has a precautionary principle. Practical realization of this principle demonstrates, however, shortcomings in its methodology. The article presents the results of two research stages. In the first stage, the documentation of 292 construction projects was examined in order to prepare the principal components of a checklist. They are correlated to the legal qualification criteria. However, they are more precise and systematic. In the second stage of the research, a survey of 47 experts was performed, and the result of the research is an innovative module of the checklist for qualification of construction projects to the habitat assessment, including questions on materials solutions. The research has proved that introduction of this proposal to the checklist may improve the quality of habitat assessments, increase their trustworthiness and ensure full exploitation of the possibilities which are given by the use of uniform research methods.
The management of Construction and Demolition (C&D) waste remains an incessant problem. Traditional ways to minimize C&D wastes lacks flexibility and long-term reliability. There is increasing focus on sustainable waste management; so there is need of innovative and sophisticated waste management approaches that focus on processes and embodies adaptability. Life Cycle Assessment (LCA) is a globally standardized methodology for environmental assessment for any product or system and also helps in process of planning and decision making. With regards to sustainable management; LCA is one of the best tools. This study reviews the prior published literatures to reveal the state-of-the-art of LCA approaches employed in C&D waste management (CDWM), especially, literatures evaluating different scenarios. This study also discusses the LCA history, concepts and methodology. A content-based analysis of literatures published in the past two decades is done. It is found that almost 70% of LCA studies were done in European countries; this shows the deficiencies in research in this area in other countries, especially in developing countries like India. Limitations, recommendations and future scope with respect to LCA on various aspects of CDWM like collection, transportation, recycling and landfilling are enumerated. This consolidated study will be beneficial for researchers and practitioners as it provides insights into employment of LCA on CDWM and to develop well-balanced CDWM model.
The rapid urbanisation and infrastructure development projects have increased infinite property regeneration and construction projects in the developed countries. This study aims to examine the current construction waste management literature, including key authors, university networks, and relevant information systems, considering four selected countries, including Australia, Canada, the United Kingdom, and the United States. This paper uses a set of novel metrics, query-based search, and social network analysis techniques for evaluating a dataset of 2337 papers published in a decade by authors from different countries investigating the topic of recycling and reuse of construction and demolition waste in order to identify prominent researchers, influential universities, collaboration practices, and research trends. The dataset of publications is collected from Scopus and analysed using a set of network analysis techniques and statistical analysis. An additional dataset of keywords was collected from the Twitter pages of engineering firms and other relevant industry organisations to assess any possible connection between industry interests and research trends. In order to present a solid analysis of the current investigations in the field, a scientometric analysis along with a rigor statistical method was adopted to carefully identify trends, detailed sub-topics, and the materials investigated in the literature. A probit regression model for testing differences between countries in recycling practices was utilised in the STATA environment. The findings show a set of network analysis and clusters that can help scholars to set their future studies based on the current advances and limitations identified in the literature. Within the dataset, 42% of publications referred to concrete waste, whilst only 2.2% included glass, 2.5% included brick, 4.3% included steel and none included wood, which shows the most common building materials have not been fully covered in the literature. Only 48 publications, or 7.4% of the dataset, originated from the three selected concrete-focused journals. It was also found that information systems appeared in the database lately; however, there is less discussion in the literature on how the integration of Geographic Information System (GIS), Buidling Information Model (BIM), 3D Printing and geo-spatial data analysis can help waste management in the field of construction. The bibliographic analysis of the selected cases shows that universities in Canada and the US exhibit more evidence of domestic collaboration and industry partnerships than universities in Australia and the UK. Additionally, there is evidence to suggest that publications with at least one industry co-author are more likely to address the issue of regulation. The outcome of this paper enables academics, engineers, and regulators to predict research trends, improve industry collaborations and utilise information systems and assign more research resources to address the identified gaps in the literature.
Using a life cycle assessment (LCA) to evaluate municipal solid waste management (MSWM) systems is strongly recommended and the approach has been used in high-income contexts. However, stakeholders in low to middle-income countries are not aware of the potential of this approach, mainly due to a lack of financial resources and technical ability. The present work introduces a LCA of MSWM system scenarios into a developing city using an academic licence for the LCA software that is available for use exclusively by researchers. The MSWM system in place in 2018 in La Paz (Bolivia) was assessed according to seven scenarios. The novelty of the research is twofold: the use of LCA academic licensing in a low to middle-income region where LCA is unknown as planning tool; and discussing the potential of the approach in conjunction with local and international stakeholders with a view to starting MSWM projects. The results of the analysis allow for the consideration of energy recovery and materials recycling as the main methods by which the environmental impact of MSW can be reduced, as has also been reported by other LCA studies conducted with full licensing of the relevant software. Moreover, the research is the basis for cooperative development projects that will adopt the LCA approach as the main assessment tool. The study discusses the importance of cooperation between universities and local governments for implementing new strategies for MSWM assessment and planning. The research is a contribution towards improving technical knowledge in developing countries for boosting sustainable development.
Rapid industrial development, mega construction projects and increased immigration are some of the reasons that the State of Qatar has recently generated an unprecedented amount of construction and demolition (C&D) waste in the country. The State is racing towards the Fédération Internationale de Football Association World Cup 2022, a fact that requires additional construction, for which it is expected to increase its rate of waste generation. Compared to other regions, there are relatively few studies in the literature that report on the C&D waste management issues of Qatar. The present work begins to address this gap by providing insights into the current state of C&D waste management practices in Qatar and by providing a mini-review on the benefits of using recycled aggregates which have only recently been allowed locally by Qatar Construction Standards. A Strengths, Weaknesses, Opportunities, and Threats analysis has been implemented, using data and information from various sources including governmental reports, industries, local waste management companies, as well as reported interviews with relevant stakeholders. Finally, several strategies were proposed and developed that could potentially be implemented by stakeholders and decision-makers, so as to improve the current status by encouraging more sustainable and viable practices.
Environmental contamination due to solid waste mismanagement is a global issue. Open dumping and open burning are the main implemented waste treatment and final disposal systems, mainly visible in low-income countries. This paper reviews the main impacts due to waste mismanagement in developing countries, focusing on environmental contamination and social issues. The activity of the informal sector in developing cities was also reviewed, focusing on the main health risks due to waste scavenging. Results reported that the environmental impacts are pervasive worldwide: marine litter, air, soil and water contamination, and the direct interaction of waste pickers with hazardous waste are the most important issues. Many reviews were published in the scientific literature about specific waste streams, in order to quantify its effect on the environment. This narrative literature review assessed global issues due to different waste fractions showing how several sources of pollution are affecting the environment, population health, and sustainable development. The results and case studies presented can be of reference for scholars and stakeholders for quantifying the comprehensive impacts and for planning integrated solid waste collection and treatment systems, for improving sustainability at a global level.
Lack of reliable data is one of the most important constraints of solid waste management. We investigated generation rates of solid waste in Tehran and the factors affecting generation rates. Data were collected from the statistical center of Tehran Waste Management Organization (TWMO). The data analysis showed that the municipal solid waste (MSW) generation was increased from 2006 to 2012; however, because of a decline in gross domestic production (GDP) per capita, a decline of the MSW generation was observed between 2012 and 2014. The correlation coefficient between the total MSW and GDP was 0.91. Thus, the MSW generation rate in Tehran was highly correlated with the GDP per capita and the rate was predictable with a high confidence. The MSW per capita per day in Tehran was 0.96 kg and 76% of the MSW was landfilled. Construction and demolition (C&D) wastes per capita per day was 5.2 kg and 81% of them were landfilled. A low recycling rate indicated that the education programs and/or public participation for waste reduction and recycling in recent years have not been efficient and a revision should be made to the current program.
Concrete production causes significant environmental damage during its entire life cycle due to the large consumption of natural aggregate. The aim of this research was to use the Life Cycle Assessment (LCA) methodology to conduct a comparative analysis of four different concrete mixtures, i.e., construction and demolition waste (CDW), incinerator ashes, marble sludge, and blast furnace slag. The LCA study was implemented in the Campania Region of Italy. The main contribution of the study was that it proposed the use of "green" recycled aggregates in concrete production in order to assess the reduction of potential adverse impacts, from both environmental and energy perspectives. SimaPro© software was used to conduct the analysis. The main results of the research showed that the recycled aggregates that were analyzed were preferable to traditional concrete. In particular, the recycled aggregate that had the least adverse impact on the environment was blast furnace waste.
The revised EU Waste Framework Directive (WFD) includes a 70 % target for recovery of construction and demolition (C&D) waste. In order to study the potential change in the resource management of the main C&D waste fractions, as a consequence of fulfilling the WFD target, a Nordic project (ENCORT-CDW) has been performed. Waste fractions studied included asphalt, concrete, bricks, track ballast, gypsum-based construction materials and wood. Recovery scenarios were identified and estimations were made regarding expected savings of primary materials, impact on transport, and pollution and emissions. For wood waste, the main differences between re-use, material recycling and energy recovery were evaluated in a carbon footprint screening based on life cycle assessment methodology. The study concluded that the EU recovery target does not ensure a resource efficient and environmentally sustainable waste recovery in its present form since: It is very sensitive to how the legal definitions of waste and recovery are interpreted in the Member States. This means that certain construction material cycles might not count in the implementation reports while other, less efficient and environmentally safe, recovery processes of the same material will count.
It is weight-based and consequently favours large and heavy waste streams. The result is that smaller flows with equal or larger resource efficiency and environmental benefit will be insignificant for reaching the target.
It does not distinguish between the various recovery processes, meaning that resource efficient and environmentally safe recovery cannot be given priority.
Improved knowledge on C&D waste generation and handling, as well as on content and emissions of dangerous substances, is required to achieve a sustainable recovery.
Currently, the majority of the construction waste (CW) has been collected without classification and simply disposed in China. To quantify the environmental impacts and provide reasonable policy recommendations, this paper conducted an assessment for the life cycle carbon emissions (CEs) for CW based on a streamlined life cycle assessment method. Three typical CW management approaches in Shenzhen City were selected to perform the case study and comparative analysis. The results show that scenario I with low recycling rate generates the largest CEs amount by 542.56 kg for 1 ton CW, followed by scenarios II and scenario III that generate 538.61 and 483.85 kg, respectively. In addition, the results show the material embody impact is the largest contributor to CEs for CW examined, accounting for 78 % of the total amount in the overall life cycle. Analysis results also show that wood, steel and concrete wastes are the top three contributors within nine materials, with proportions of 25, 23 and 13 %, respectively. Therefore, the most effective way to decrease the CEs of CW is minimizing the generation of CW, since the CEs of the majority of waste are not sensitive to alteration of treatment methods or recycling rate.
Since the construction sector uses 50% of the Earth’s raw materials and produces 50% of its waste, the development of more durable and sustainable building materials is crucial. Today, Construction and Demolition Waste (CDW) is mainly used in low level applications, namely as unbound material for foundations, e.g., in road construction. Mineral demolition waste can be recycled as crushed aggregates for concrete, but these reduce the compressive strength and affect the workability due to higher values of water absorption. To advance the use of concrete rubble, Completely Recyclable Concrete (CRC) is designed for reincarnation within the cement production, following the Cradle-to-Cradle (C2C) principle. By the design, CRC becomes a resource for cement production because the chemical composition of CRC will be similar to that of cement raw materials. If CRC is used on a regular basis, a closed concrete-cement-concrete material cycle will arise, which is completely different from the current life cycle of traditional concrete. Within the research towards this CRC it is important to quantify the benefit for the environment and Life Cycle Assessment (LCA) needs to be performed, of which the results are presented in this paper. It was observed that CRC could significantly reduce the global warming potential of concrete.
Construction and demolition wastes (C&DW) are usually recognized as not dangerous, but their accumulation can generate serious environmental problems. In spite of C&DW high potential to be reused/recycled, the practical procedures need to be assessed in terms of environmental consequences. The objective of this study is to quantify the environmental impacts of C&DW recycling/reuse, specifically in the production of aggregate 0/30 mm, comparative to those generated during the natural inert processing, in terms of global impacts addressing the whole process and for each technological phase. The analysis was carried out using Life Cycle Assessment methodology, assisted by SimaPro software, and based on primary data collected directly from the Italian Emilia Romagna region. Three methods were used for impact quantification: Eco-Indicator 99, EDIP/UMIP and Cumulative Energy Demand. The analysis revealed that the environmental impacts generated by C&DW recycling/reuse accounting for about 40% of the impacts induced by natural inert processing.
The significant amount of waste generated from construction demolition has become a chronic problem in many developing countries. Using data obtained from demolition contractors and various other sources, this paper proposes a framework for proper handling of construction demolition waste (CDW) to serve as a decision support tool in countries suffering from the lack of national CDW management guidelines. The framework is then demonstrated through a case study in the city of Beirut, Lebanon, and a sensitivity analysis is carried out to examine the economic feasibility of developing a recycling facility. The analysis showed that in order for a facility to be feasible, a gate fee should be charged in the presence of a market for recycled aggregates. The results confirm the significance of instigating and implementing legislation to control illegal dumping, constructing, and managing engineered landfills, and establishing markets for recycled CDW.
In this article we have elaborated a consistent framework for the quantification and evaluation of eco-efficiency for scenarios for waste treatment of construction and demolition (C&D) waste. Such waste systems will play an increasingly important role in the future, as there has been for many years, and still is, a significant net increase in stock in the built environment. Consequently, there is a need to discuss future waste management strategies, both in terms of growing waste volumes, stricter regulations, and sectorial recycling ambitions, as well as a trend for higher competition and a need for professional and optimized operations within the C&D waste industry. It is within this framework that we develop and analyze models that we believe will be meaningful to the actors in the C&D industry. Here we have outlined a way to quantify future C&D waste generation and have developed realistic scenarios for waste handling based on today's actual practices. We then demonstrate how each scenario is examined with respect to specific and aggregated cost and environmental impact from different end-of-life treatment alternatives for major C&D waste fractions. From these results, we have been able to suggest which fractions to prioritize, in order to minimize cost and total environmental impact, as the most eco-efficient way to achieve an objective of overall system performance.
Recycling of construction and demolition waste contributes decisively to the saving of natural mineral resources. In Germany, processed mineral construction and demolition waste from structural engineering is used nearly exclusively in civil engineering (earthwork and road construction sector) as open-loop recycling. Due to the planned stricter limit values for the protection of soil and water, however, this recycling path in civil engineering may no longer be applicable in the future. According to some new guidelines and standards adopted recently, recycled aggregates may also be used for concrete production in the structural engineering sector (closed-loop recycling). Wastes from the structural engineering sector can thus be kept in a closed cycle, and their disposal on a landfill can be avoided. The present report focuses on the determination of maximum waste volumes that may be handled by this new recycling option. Potential adverse effects on the saving of resources and climate protection have been analysed. For this purpose, materials flow analysis and ecobalancing methods have been used.
The study compares life cycle environmental implications of two construction and demolition waste (C&DW) management alternatives, inert landfilling and integrated wet recycling, on many impact categories under several scenarios. Integrated wet-recycling valorizes coarse aggregates, sand, and soil, recovering over 95 percent of incoming C&DW waste. Using data from recycling plants operational in New Delhi complemented by the ecoinvent database, the study deploys SimaPro software and explores potential environmental implications of recycling compared to landfilling predominantly inert stony C&DW in urban India. Processes from the ecoinvent database were customized for Indian scenario using mix of primary and secondary data. ReCiPe method was used for impact assessment. Scenarios were developed to capture uncertainties in plant operational efficiencies, the share of carbon neutral electricity in overall generation mix, and avoided transport of natural materials. The results suggest that due to greater material recovery, integrated wet recycling is environmentally sound alternative compared to landfilling under most scenarios. Higher share of cleaner electricity lowered carbon emissions, but increased mineral scarcity and eutrophication among other impact categories, indicating environmental tradeoffs associated with energy intensive recycling process. Integrated recycling promises to lower environmental footprint of urban India while lowering requirement of virgin natural materials.
Construction and demolition waste represents a significant waste flow, both in Brazil and in other countries. According to specific Brazilian legislation, since 2004 construction and demolition waste can no longer be disposed of in open dumps, municipal solid waste landfills, slopes, waterways and environmental protected areas. Construction and demolition waste should preferably be recycled, but just a small amount of it returns to the construction industry production chain in Brazil. This work aims both to present diagnoses of the construction and demolition waste management in Brazil, the European Union and the United States and to compare their results. It is concluded that Brazil presents performance indicators in relation to construction and demolition waste management well below those found for the other analysed countries. Furthermore, differences and similarities are identified and potentials for improvement in the current situation of construction and demolition waste in Brazil are discussed.
The analysis of municipal solid waste (MSW) selective collection (SC) scenarios is compulsory for planning future policies and actions towards circular economy. The use of geographic information system (GIS) is appropriated for obtaining reliable data about SC yields and management costs. However, in low-middle income countries, advanced assessments are difficult to introduce due to the lack of technical knowledge, financial support and the presence of the informal recycling sector. This research aims to assess the main potentialities of the introduction of SC systems in a Bolivian developing city taking into account the informal SC system in place. The study was conducted with QGIS3.8 software in order to evaluate the main advantages of the implementation of formal and informal recycling chains. Results reported that, comparing the implementation of formal SC of MSW with the scenario that considered the inclusion of the informal recycling, the activity of waste pickers allows reducing the expenses of about 10%, increasing the recycling rate of about 3.5%, and reducing the distances traveled with com-pactor trucks of about 7%. It means that, the annual path traveled by the collection trucks for gathering about 16,000ty À1 , is reduced by 2734kmy À1 , reducing the waste disposed to landfill of about 543.6ty À1 and the expenses of about €59,000 per year. The presentation of these results to policy-makers can support decision-making boosting the implementation of recycling activities including waste pickers. The study provided a contribution to the scientific literature assessing the main challenges and opportunities for implementing the circular economy in developing regions.
Increased stress on raw material and limited landfill space due to increasing rates of urbanization have encouraged efforts to divert Construction and Demolition Waste (C&DW) away from landfills toward sorting, recycling, and reusing. While these efforts have been successful in some countries (e.g., Germany, Netherlands), developing countries tend to suffer from illegal and haphazard dumping of C&DW. This study presents an optimization based decision support tool to select a cost and environmentally effective set of abandoned quarries to serve as C&DW landfills and processing facilities. The tool is composed of a GIS model and a mixed integer linear program that accounts for the complete waste management chain. A case study in Lebanon served as a testbed for the tool: A multi-criteria analysis was first used in GIS to evaluate the environmental suitability of candidate quarries based on five thematic groups: socio-economic, topography, geology, hydrology and infrastructure. The most suitable quarries were then inputted to the optimization model. Two out of 148 abandoned quarries in Mount Lebanon were deemed suitable for rehabilitation under the objectives set yielding a profit of 125 million US dollars over a 20 year span. Future challenges include enhancing the model by incorporating time and accounting for more recycling technologies.
This article presents a brief analysis of sustainable development in the context of contemporary productive forces and production relationships, as well as their contradictions regarding the limits of nature. For this particular evaluation, it was necessary to present a logical critique of ecological economics and environmental economics. To corroborate this inherent contradiction, certain data were included, such as surplus food production, the use of agrochemicals, the increasing average temperature of the planet due to the emission of greenhouse gases, and inequality in the distribution of income. Subsequently, an analysis of these data was performed. Finally, some general elements related to a new way of thinking about the productive forces and production relationships were proposed, which focus on a production dynamic directed toward basic human needs instead of market needs.
The aim of this study was to assess the economic and environmental advantages of implementing reverse logistics to recycle solid waste from construction companies. The adopted research method was based on a systematic literature review and two case studies. For the economic assessment, the return on investment, the internal rate of return, and the discounted payback factors were considered, while the material intensity factor was used for the environmental impact assessment. This study shows that there are economic and environmental advantages associated with the use of reverse logistics for solid waste treatment and recycling. In 2016, the purchase of recycled blocks resulted in a profit of over US$45,000 for one company, and another company earned almost US$250,000 in the same year by recycling solid waste from manufacturing blocks and selling iron, wood, paper, and plastics. Furthermore, the environmental impact was reduced. This paper contributes to the dissemination of knowledge regarding the advantages of adopting reverse logistics for recycling construction and demolition waste, and creates new opportunities for companies.
Construction and Demolition Waste (CDW) has been identified as a priority waste stream by the European Union due to its significant generation level and its high recycling potential. The purpose of the present study, which was supported by the local government of Lombardy Region (Italy), is to apply the Life Cycle Assessment (LCA) methodology to evaluate the environmental performance of the current regional management of CDW and to identify critical aspects and possible improving actions. The focus has been placed on the waste fraction mostly present in CDW that is the mixed non-hazardous waste (identified by the European Waste Code 170904). In the recycling plants, this is usually blended with cement, tiles and ceramics, and, to a lesser extent, with bituminous mixture and gypsum-based waste to obtain mixed recycled aggregates. These are mostly used in road construction works and in environmental fillings/restoration.
The LCA of the current CDW management system showed that the induced environmental impacts are in general higher than the benefits arising from recycling activities. At the same time the current system performs better than a scenario where all the CDW is sent to landfill. On the basis of several sensitivity and scenario analyses, a best-case scenario has been defined by optimizing all the main system parameters. Finally, recommendations were formulated to improve the environmental performances of the system.
India faces the daunting challenge of rapidly increasing municipal, industrial and agricultural waste generation due to several factors-population increase, urbanization, and economic growth. The result is significant air, soil and water pollution, as well as safety problems and health impacts upon both workers and nearby residents. Recycling and composting programs are unable to keep pace with the growth of waste, although small startup companies and non-governmental organizations are introducing new solutions ranging from high-tech waste processing to improved training and support for waste picker communities. For India to achieve continued economic growth, poverty alleviation, hunger elimination, human development, and environmental improvement, new transformative solutions are needed rather than incremental improvements. This paper proposes an integrated systems approach towards waste policies and practices, based on an understanding of the interdependence among economic, environmental, and social processes. Drawing upon the results of a conference on Waste Management Innovation held in Mumbai in April 2017, the paper examines the current status of waste management in India, provides examples of innovative practices and emerging technologies that can help to ameliorate the situation, and offers recommendations for a path forward.
Urgent solutions are needed in Europe to deal with construction and demolition waste (CDW). EU policy has contributed to significantly reducing the amount of CDW going to landfill, but most of the effort has been put in downcycling practices. Therefore, further policies are needed to stimulate high-quality recycling of CDW.
The present paper presents a combined life cycle assessment (LCA) and life cycle costing (LCC) methodologies to analyse the environmental and the economic drivers in four alternative CDW end-of-life scenarios in the region of Flanders, in Belgium. The four analysed alternatives are (i) landfilling, (ii) downcycling, (iii) advanced recycling and (iv) recycling after selective demolition.
LCA results show that landiflling is the scenario having the highest environmental impacts in terms of person equivalent (PE), followed by downcycling and recycling (-36%) and recycling after selective demolition (−59%). The decrease in environmental impacts is mostly due to the avoided landfilling of CDW and the recovery of materials from selective demolition. LCC results indicate that landfilling is the scenario bearing the highest total economic costs. This is due to the high landfill tax in Flanders. The recycling after selective demolition bears the second highest cost.
The increase of high-quality CDW recycling can significantly reduce the overall environmental impact of the system. Implementing a high landfill tax, increasing the gate fee to the recycling plant, and boosting the sales price of recycled aggregates are the most effective drivers to facilitate a transition towards a more sustainable CDW management system.
The paper demonstrates that the combined LCA and LCC results can highlight the environmental and economic drivers in CDW management. The results of the combined analysis can help policymakers to promote the aspects contributing to sustainability and to limit the ones creating a barrier.
The large amount of concrete waste (CW) generated during the construction and demolition stages and the improper management of it often results in considerable environmental impact.The main purpose of this study is to identify the most eco-efficiency scenario in CW management. The life cycle assessment (LCA) modelling is used to assess the environmental impact, GHG emissions and the life cycle cost (LCC) is used as an extension of LCA in the term of economic dimension. Decision making in waste management often come hand in hand with economic incentives. Aligning both LCA and LCC in environmental-cost effectiveness as the eco-efficiency analysis helps in measuring sustainability. Scenarios were built to access different CW options. Scenario 1 (S1) depicts the landfilling. Scenario 2, 3, and 4 (S2, S3, & S4) are the recycling scenario where CW is recycled into concrete aggregate (RCA) to substitute the natural aggregate (NA) in road construction and in recycled aggregate concrete (RAC) production. Results show that S3, recycling of CW to substitute NA in concrete production has the highest eco-efficiency of 1.72 while landfilling has the lowest eco-efficiency of 1.15. Higher eco-efficiency means lower environmental and cost impacts. CW is preferably uses as a substitution of the NA to reduce the need in mining of NA. This study also identified that transportation distances and mining activity are the main contributors to GHG emissions and cost impact. Sensitivity analysis evaluated the what-if scenario of building a mobile material recovery facilities (MRF) within 3 km from waste source site. The results show that the what-if scenario (S3' with 1.78 eco-efficiency) could possibly reduces 50.8% GHG emissions and 68.1% of cost saving as compared to landfilling scenario.
The natural and mixed recycled aggregate production for use as road base and subbase have been compared through an attributional life cycle assessment. The primary data have been collected in a basalt natural aggregate production facility and in a recycling facility of mixed aggregate, both located in Southeast Brazil. The topic is important since there is a local increasing demand for aggregate use in road construction and there are no studies related to the environmental aspects of the production of natural and mixed recycled aggregate, and no suitable, site-specific data are available to develop a reliable life cycle investigation. The potential environmental impacts related to the two production processes have been estimated by using the Impact 2002þ methodology. The results show that the production of recycled aggregates is preferable to that of natural materials for the impact categories of "respiratory inorganics", "terrestrial ecotoxicity", "land occupation", "global warming" and "non-renewable energy". A specific sensitivity analysis suggests that the mixed recycled aggregate is a better option for all the environmentally impact categories if the distance of the recycling facility from the consumer is up to 20 tkm longer than the distance of the natural aggregate production facility from the consumer of this product. These results, and those of the detailed life cycle inventory and impact assessment, may support the decision making process in the same field as well as the development of similar life cycle assessment studies, provided that both be appropriately adapted to the specific conditions of the system under analysis.
This study provides an environmental impact assessment of the black copper smelting route for the processing and recovery of copper and other valuable metals such as gold and silver from waste printed circuit boards (PCB). Thermodynamic based analysis was conducted to simulate the recycling process and a life cycle assessment was carried out to estimate and compare the environmental impact of the two scenarios: (1) recycling of precious metal out of waste PCBs through secondary copper smelting (Electronic Waste Processing, EWP); and (2) secondary copper recycling without adding electronic waste to the feed (SCR). The results of the study revealed that environmental impacts of using e-waste along with low-grade copper scrap in existing smelters to recover precious metals are dependent on the distance the material feed travels to the smelter and the means of electricity supplying the smelter. It is also found that the impact of the EWP scenario for climate change, freshwater eutrophication, and fossil depletion is significantly higher than those obtained from the SCR scenario and it is mainly because the metal and oxide dust in former scenario needs to be further refined to recover metals such as nickel, zinc and lead. The results also confirm that 10% cut in electricity usage in EWP scenario, has the higher environmental benefit in almost all dominant categories.
The natural and mixed recycled aggregate production for use as road base and subbase have been compared through an attributional life cycle assessment. The primary data have been collected in a basalt natural aggregate production facility and in a recycling facility of mixed aggregate, both located in Southeast Brazil. The topic is important since there is a local increasing demand for aggregate use in road construction and there are no studies related to the environmental aspects of the production of natural and mixed recycled aggregate, and no suitable, site-specific data are available to develop a reliable life cycle investigation. The potential environmental impacts related to the two production processes have been estimated by using the Impact 2002+ methodology. The results show that the production of recycled aggregates is preferable to that of natural materials for the impact categories of “respiratory inorganics”, “terrestrial ecotoxicity”, “land occupation”, “global warming” and “non-renewable energy”. A specific sensitivity analysis suggests that the mixed recycled aggregate is a better option for all the environmentally impact categories if the distance of the recycling facility from the consumer is up to 20 tkm longer than the distance of the natural aggregate production facility from the consumer of this product. These results, and those of the detailed life cycle inventory and impact assessment, may support the decision making process in the same field as well as the development of similar life cycle assessment studies, provided that both be appropriately adapted to the specific conditions of the system under analysis.
A large amount of construction and demolition waste is being generated owing to rapid urbanisation in Indian cities. A reliable estimate of construction and demolition waste generation is essential to create awareness about this stream of solid waste among the government bodies in India. However, the required data to estimate construction and demolition waste generation in India are unavailable or not explicitly documented. This study proposed an approach to estimate construction and demolition waste generation using waste generation rates and demonstrated it by estimating construction and demolition waste generation in Chennai city. The demolition waste generation rates of primary materials were determined through regression analysis using waste generation data from 45 case studies. Materials, such as wood, electrical wires, doors, windows and reinforcement steel, were found to be salvaged and sold on the secondary market. Concrete and masonry debris were dumped in either landfills or unauthorised places. The total quantity of construction and demolition debris generated in Chennai city in 2013 was estimated to be 1.14 million tonnes. The proportion of masonry debris was found to be 76% of the total quantity of demolition debris. Construction and demolition debris forms about 36% of the total solid waste generated in Chennai city. A gross underestimation of construction and demolition waste generation in some earlier studies in India has also been shown. The methodology proposed could be utilised by government bodies, policymakers and researchers to generate reliable estimates of construction and demolition waste in other developing countries facing similar challenges of limited data availability.
This paper studies the potential environmental impact of recycled coarse aggregate (RCA) for concrete production in China. According to the cradle-to-cradle theory, a closed-loop life cycle assessment (LCA) on recycled aggregate concrete (RAC) utilization in China with entire local life cycle inventory (LCI) is performed, regarding the environmental influence of cement content, aggregate production, transportation and waste landfilling. Special attention is paid on the primary resource and energy conservation, as well as climate protection induced by RAC applications. Environmental impact between natural aggregate concrete (NAC) and RAC are also compared. It is shown that cement proportion and transportation are the top two contributors for carbon dioxide (CO2) emissions and energy consumption for both NAC and RAC. Sensitivity analysis also proves that long delivery distances for natural coarse aggregate (NCA) leave a possible opportunity for lowering environmental impact of RAC in China.
Construction and demolition (C&D) waste is a pressing issue not only in Malaysia, but it is also a worldwide concern including the developed countries as well. C&D waste should be managed throughout the construction cycle. The concept of circular economy (CE) is an emerging notion that has the potential to be utilized as waste minimization approach. This paper aims to assess the potentials of incorporating the CE concept as an approach to minimizing C&D wastes, by developing a CE-based theoretical framework for C&D waste management in Malaysia. In line with this objective, a systematic review has been conducted to determine how CE can be operationalised as a strategy to minimize wastes, while considering it as a key factor for mitigating the environmental impacts. Based on the literature review, a CE-based theoretical framework has been proposed using Malaysia as a case study. The framework has been developed following a three-layer approach namely micro-, meso-, and macro-levels. Waste minimization strategies have been identified for each level taking into account the main stages in the construction industry, i.e., planning, designing, procurement, construction, and demolition. The different stakeholders involved at each stage and their interactions in the stages have also been identified.
This paper provides a review of the literature that applies the life cycle assessment (LCA) methodology to the assessment of the environmental performance of the life cycle of construction and demolition waste (CDW) management systems. This article is focused on generating a general mapping of the literature and on identifying the best practices in compliance with LCA framework and proposing directions for future LCA studies in this field. The temporal evolution of the research in this field and the aim of the studies have grown in parallel with the legal framework related to waste and energy efficiency of buildings. Most studies have been published in Europe, followed by USA. Asia and Australia, being at an incipient application stage to the rest of the world. Topics related to "LCA of buildings, including their EoL" and "LCA of general CDW management strategies" are the most frequently analysed, followed by "LCA of EoL of construction elements" and "LCA of natural material vs recycled material". Regarding the strategies, recycling off-site and incineration, both combined with landfill for the rejected fractions, are the most commonly applied. Re-use or recycling on-site is the strategy least applied. The key aspect when LCA is applied to evaluate CDW management systems is the need to normalise which processes to include in the system boundary and the functional unit, the use of inventory data adapted to the context of the case study and the definition of a common set of appropriate impact assessment categories. Also, it is important to obtain results disaggregated by unit processes. This will allow the comparison between case studies.
Life cycle assessment (LCA) modelling of construction and demolition waste (C&DW) management was carried out. The functional unit was management of 1 Mg mineral, source separated C&DW, which is either utilised in road construction as a substitute for natural aggregates, or landfilled. The assessed environmental impacts included both non-toxic and toxic impact categories. The scenarios comprised all stages of the end-of-life management of C&DW, until final disposal of all residues. Leaching of inorganic contaminants was included, as was the production of natural aggregates, which was avoided because of the use of C&DW. Typical uncertainties related to contaminant leaching were addressed. For most impact categories, utilisation of C&DW in road construction was preferable to landfilling; however, for most categories, utilisation resulted in net environmental burdens. Transportation represented the most important contribution for most nontoxic impacts, accounting for 60-95 per cent of these impacts. Capital goods contributed with negligible impacts. Leaching played a critical role for the toxic categories, where landfilling had lower impacts than utilisation because of the lower levels of leachate per ton of C&DW reaching the groundwater over a 100-year perspective. Leaching of oxyanions (As, V and Sb) was critical with respect to leaching. Typical experimental uncertainties in leaching data did not have a pivotal influence on the results; however, accounting for Cr immobilisation in soils as part of the impact assessment was critical for modelling the leaching impacts. Compared with the overall life cycle of building and construction materials, leaching emissions were shown to be potentially significant for toxicity impacts, compared with contributions from production of the same materials, showing that end-of-life impacts and leaching should not be disregarded when assessing environmental impacts from construction products and materials. CO2 uptake in the C&DW corresponding to 15 per cent carbonation could out-balance global warming impacts from transportation; however, carbonation would also likely result in increased toxicity impacts due to higher leaching of oxyanions.
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The use of recycled concrete aggregates (RCA) in applications other than road sub-layers is limited by two factors: the high porosity of RCA in comparison with natural aggregates, and the restrictions set forth in standards and building codes. Research efforts aimed at alleviating these restrictions are focused on improving the quality of coarse RCAs by reducing the amount of adhered cement pastes, which is the weakest element in this system and influences the rheological behaviour.
This paper presents an analysis of the environmental impacts of the recent mechanical and thermo-mechanical processing techniques which produce high performance RCA by reducing the volume of adhered cement paste. Based on published data, processing scenarios were established. These scenarios permit making rough estimates of energy consumption, CO2 emissions, fines generation and product quality. Using these data and the available emission factors from several countries, an objective comparison was made between these innovating processes and conventional recycling.
The production of fines increases from 40% up to as much as 70% as the volume of adhered cement paste on the RCA is reduced. Fuel fed thermo-mechanical process energy consumption, per tonne of recycled aggregate, varies between 36 and 62 times higher than conventional recycling processes. Mechanical processing, combined with microwave heating, increases energy consumption from 3 to a little more than 4 times conventional recycling. Consequently, CO2 emissions released by conventional coarse aggregate production go from 1.5 to 4.5 kgCO2/t, to around 200 kgCO2/t, for that of fossil fuel fed thermo-mechanical treatments.
Mechanical and mechanical/microwave treatments appear to have the greatest environmental potential. Notwithstanding, the further development of markets for fines is crucial for reducing environmental loads.
The continuously increasing solid waste generation worldwide calls for management strategies that integrate concerns for environmental sustainability. By quantifying environmental impacts of systems, life cycle assessment (LCA) is a tool, which can contribute to answer that call. But how, where and to which extent has it been applied to solid waste management systems (SWMSs) until now, and which lessons can be learnt from the findings of these LCA applications? To address these questions, we performed a critical review of 222 published LCA studies of SWMS. We first analysed the geographic distribution and found that the published studies have primarily been concentrated in Europe with little application in developing countries. In terms of technological coverage, they have largely overlooked application of LCA to waste prevention activities and to relevant waste types apart from household waste, e.g. construction and demolition waste. Waste management practitioners are thus encouraged to abridge these gaps in future applications of LCA. In addition to this contextual analysis, we also evaluated the findings of selected studies of good quality and found that there is little agreement in the conclusions among them. The strong dependence of each SWMS on local conditions, such as waste composition or energy system, prevents a meaningful generalisation of the LCA results as we find it in the waste hierarchy. We therefore recommend stakeholders in solid waste management to regard LCA as a tool, which, by its ability of capturing the local specific conditions in the modelling of environmental impacts and benefits of a SWMS, allows identifying critical problems and proposing improvement options adapted to the local specificities.
This work is a part of a wider study involving the economic and environmental implications of managing construction and demolition waste (CDW), focused on the operation of a large scale CDW recycling plant. This plant, to be operated in the Lisbon Metropolitan Area (including the Setúbal peninsula), is analysed for a 60 year period, using primary energy consumption and CO2eq emission impact factors as environmental impact performance indicators.Simplified estimation methods are used to calculate industrial equipment incorporated, and the operation and transport related impacts. Material recycling – sorted materials sent to other industries, to act as input – is taken into account by discounting the impacts related to industrial processes no longer needed.This first part focuses on calculating the selected impact factors for a base case scenario (with a 350 tonnes/h installed capacity), while a sensitivity analysis is provided in part two. Overall, a 60 year global primary energy consumption of 71.4 thousand toe (tonne of oil equivalent) and a total CO2eq emission of 135.4 thousand tonnes are expected. Under this operating regime, around 563 thousand toe and 1465 thousand tonnes CO2eq could be prevented by replacing raw materials in several construction materials industries (e.g.: ferrous and non-ferrous metals, plastics, paper and cardboard).
The ever increasing quantity of construction and demolition waste (C&DW) in Italy is presently challenging public administrators, which strive to ensure that collection and recycling are sustainably managed and need to understand whether and to what extent recycled aggregates can complement natural aggregates in a sustainable supply mix (SSM) for the construction industry. The paper presents a research aimed at analysing energy and environmental implications of the C&DW recycling chain in the administrative territory of Provincia di Torino in Northern Italy, with 2.25 million inhabitants and yearly generation of 1.8 million tons of C&DW. A combined Geographical Information System (GIS) and Life Cycle Assessment (LCA) model was developed using site-specific data and paying particular attention to land use, transportation and avoided landfill: crucial issues for sustainable planning and management. A GIS was used to handle data and information about 89 recycling plants, including technological features, output and physical–mechanical characteristics of recycled aggregate. The LCA methodology was used to identify and quantify energy and environmental loads, under different assumptions relevant to delivery distances, quality of recycled aggregates, local availability of natural aggregates and geographical coverage of market demand. The C&DW recycling chain was proved to be eco-efficient, as avoided impacts were found to be higher than the induced impacts for 13 out of 14 environmental indicators. It was also estimated that the transportation distance of recycled aggregate should increase 2–3 times before the induced impacts outweigh the avoided impacts.
Part I of this study deals with the primary energy consumption and CO(2)eq emissions of a 350tonnes/h construction and demolition waste (CDW) recycling facility, taking into account incorporated, operation and transportation impacts. It concludes that the generated impacts are mostly concentrated in operation and transportation, and that the impacts prevented through material recycling can be up to one order of magnitude greater than those generated. However, the conditions considered for the plant's operation and related transportation system may, and very likely will, vary in the near future, which will affect its environmental performance. This performance is particularly affected by the plant's installed capacity, transportation fuel and input CDW mass. In spite of the variations in overall primary energy and CO(2)eq balances, the prevented impacts are always higher than the generated impacts, at least by a factor of three and maybe even as high as 16times in particular conditions. The analysis indicates environmental performance for variations in single parameters, except for the plant's capacity, which was considered to vary simultaneously with all the others. Extreme best and worst scenarios were also generated to fit the results into extreme limits.
Building demolition waste constitutes a major component of municipal solid waste in Kuwait. Over 90% of this waste is currently land-filled, causing extreme pressure on the available land-fill sites. At the same time, the sources of natural aggregates are almost depleted, and there is an increasing demand because of the increased construction and maintenance activities. This article presents the results of a technical feasibility study into meeting this need by recycling the aggregates obtained from building demolition waste for asphalt concrete. The Marshall test, the immersion compression test, the loss of stability test, and the wheel track test were performed to evaluate the asphalt concrete made with recycled aggregate. The results showed that the asphalt concrete produced using an aggregate of demolition waste met all the requirements of local specifications.
Constant and rapid increase in construction and demolition (C&D) waste generation and consumption of natural aggregate for concrete production became one of the biggest environmental problems in the construction industry. Recycling of C&D waste represents one way to convert a waste product into a resource but the environment benefits through energy consumption, emissions and fallouts reductions are not certain. The main purpose of this study is to determine the potentials of recycled aggregate concrete (concrete made with recycled concrete aggregate) for structural applications and to compare the environmental impact of the production of two types of ready-mixed concrete: natural aggregate concrete (NAC) made entirely with river aggregate and recycled aggregate concrete (RAC) made with natural fine and recycled coarse aggregate. Based on the analysis of up-to-date experimental evidence, including own tests results, it is concluded that utilization of RAC for low-to-middle strength structural concrete and non-aggressive exposure conditions is technically feasible. The Life Cycle Assessment (LCA) is performed for raw material extraction and material production part of the concrete life cycle including transport. Assessment is based on local LCI data and on typical conditions in Serbia. Results of this specific case study show that impacts of aggregate and cement production phases are slightly larger for RAC than for NAC but the total environmental impacts depend on the natural and recycled aggregates transport distances and on transport types. Limit natural aggregate transport distances above which the environmental impacts of RAC can be equal or even lower than the impacts of NAC are calculated for the specific case study.
This life cycle assessment study analyses material and energy recovery within integrated municipal solid waste (MSW) management systems, and, in particular, the recovery of the source-separated materials (packaging and organic waste) and the energy recovery from the residual waste. The recovery of materials and energy are analysed together, with the final aim to evaluate possible optimum levels of source-separated collection that lead to the most favourable energetic and environmental results; this method allows identification of an optimum configuration of the MSW management system. The results show that the optimum level of source-separated collection is about 60%, when all the materials are recovered with high efficiency; it decreases to about 50%, when the 60% level is reached as a result of a very high recovery efficiency for organic fractions at the expense of the packaging materials, or when this implies an appreciable reduction of the quality of collected materials. The optimum MSW management system is thus characterized by source-separated collection levels as included in the above indicated range, with subsequent recycling of the separated materials and energy recovery of the residual waste in a large-scale incinerator operating in combined heat and power mode.
This paper presents an application of the ELECTRE III decision-aid method in the context of choosing a sustainable demolition waste management strategy for a case study in the city of Lyon, France. This choice of waste management strategy takes into consideration the sustainable development objectives, i.e. economic aspects, environmental consequences, and social issues. Nine alternatives for demolition waste management were compared with the aid of eight criteria, taking into account energy consumption, depletion of abiotic resources, global warming, dispersion of dangerous substances in the environment, economic activity, employment, and quality of life of the local population. The case study concerned the demolition of 25 buildings of an old military camp. Each alternative was illustrated with different waste treatments, such as material recovery, recycling, landfilling, and energy recovery. The recommended solution for sustainable demolition waste management for the case study is a selective deconstruction of each building with local material recovery in road engineering of inert wastes, local energy recovery of wood wastes, and specific treatments for hazardous wastes.
United Nation Environment Programme
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