A causal municipal solid waste management model for sustainable cities in Vietnam under uncertainty: A comparison

Resources, Conservation & Recycling 154 (2020) 104599

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A causal municipal solid waste management model for sustainable cities in Vietnam under uncertainty: A comparison

T

Feng Ming Tsaia, Tat-Dat Buia, Ming-Lang Tsengb,c,*, Kuo-Jui Wud a

Department of Shipping and Transportation Management, National Taiwan Ocean University, Taiwan Institute of Innovation and Circular Economy, Asia University, Taiwan c Department of Medical Research, China Medical University Hospital, Taiwan d School of Business, Dalian University of Technology, China b

A R T I C LE I N FO

A B S T R A C T

Keywords: Municipal solid waste management Exploratory factor analysis Fuzzy decision-making trial and evaluation laboratory Cities comparison

There are existing inadequate and ineffective practices that are not only common in Vietnam but also explicit in each municipal area. This study compares the municipal solid waste management attributes of cities in Vietnam under uncertainty. The uncertainties include the interrelationships among the attributes, linguistic preferences and qualitative information on the attributes. This study applies exploratory factor analysis to test the validity and reliability of the proposed attributes. Fuzzy set theory is used to translate the linguistic references into the qualitative attributes of municipal solid waste management. The decision-making trial and evaluation laboratory is used to address the interrelationships among the attributes. This study identifies the causal interrelationships among attributes using qualitative information, and a set of 14 attributes is defined and found to be valid and reliable for measurement. The results show that technical integration and social acceptability are the aspects that drive municipal solid waste management. Treatment innovations, safety and health, economic benefits, and technology functionality and appropriateness are determined to be the linkage criteria. The distinctions between cities are identified, Hanoi focuses on the institutional and organizational administration framework, whereas resource efficiency is an aspect of specific concern in Danang, and Ho Chi Minh City prioritized financial and operational requirements and facilities and infrastructure requirements. The implications for theory and practice are discussed.

1. Introduction Municipal solid waste (MSW) has been recognized as an important problem in recent decades worldwide (Asefi and Lim, 2017; Coban et al., 2018a, 2018b; Kharat et al., 2019). Developing countries, including Vietnam, are currently aiming to improve their waste collection service quality to reduce uncontrolled or illegal discarding (Brunner and Fellner, 2007; United Nations Environment Programme (UNEP, 2009). However, problems frequently occur due to a lack of ability within municipal authorities in terms of administration, financial resources, and weak handling of complexity and multidimensional systems (Diaz-Barriga-Fernandez et al., 2017; Tan et al., 2014). Municipal solid waste management (MSWM) is recognized not only as providing human health protection but also as playing an essential role in sustaining environmental, social, and economic (triple bottom line, TBL) wellbeing (Cervantes et al., 2018). Inadequate MSWM processes have negative effects on social wellbeing, local resources and the

environment (Yukalang et al., 2017). The MSW system in Vietnam, which is solely grounded in economic concerns, cannot be considered as having completely acceptable practices (Heidari et al., 2019). Moreover, each geographical area offers different evaluation requirements for waste generation and its disposal terminus that are consistent with its development goals and policy aims (Cervantes et al., 2018). Thus, there is a need to pay special attention to both the immediate and longterm effects of MSWM not only overall but also for the specific context of each municipal area. Prior studies have been undertaken to determine the attributes influencing MSWM (Guerrero et al., 2013; Soltani et al., 2015; Singh and Basak, 2018). Soltani et al. (2015) emphasized MSWM as a complex procedure that includes multiple ecological and sociocultural attributes. Mirdar Harijani et al. (2017) provided a framework that is capable of balancing the TBL perspectives on sustainability with a focus on recycling and disposal utilization processes. Erkut et al. (2008) investigated environmental problems for a regional comparison and

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Corresponding author. E-mail addresses: [email protected] (F.M. Tsai), [email protected] (T.-D. Bui), [email protected] (M.-L. Tseng), [email protected] (K.-J. Wu). https://doi.org/10.1016/j.resconrec.2019.104599 Received 24 June 2019; Received in revised form 8 October 2019; Accepted 15 November 2019 0921-3449/ © 2019 Elsevier B.V. All rights reserved.

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discusses the study’s implications, and limitations and future studies are discussed in the last section.

contraction to approach sustainable development in the MSWM context. Singh and Basak (2018) virtually compared MSW with multi-solutions for prevailing production plant processes to avoid economic and environmental problems. The MSWM attributes investigated mainly adopt TBL perspectives (Diaz-Barriga-Fernandez et al., 2017; Mohammadi et al., 2019; Su et al., 2007). There are fundamental challenges in sustainability approaches that address the inconsistency of TBL (Heidari et al., 2019). Kharat et al. (2019) argued that integrating social objects into environmental and economic targets in an MSWM system requires the incorporation of additional modeling techniques. Cervantes et al. (2018) adopted the TBL and associated it with technical aspects related to MSWM to deliver management performance. The technical integration of municipal waste streams considering the TBL helps to propel MSWM towards sustainability. Marshall and Farahbakhsh (2013) argued that extensive multiplicity of social groups or ethnic communities significantly affects municipalities’ ability to execute MSWM strategies. An integrated model is needed to include multidimensional qualitative features and strategic characteristics (Kharat et al., 2019). However, few studies have accounted for this crucial subject in their interpretations. Guerrero et al. (2013) suggested that decision-makers should be required to report upon the situation in cities and make positive alterations, developing integrated waste management strategies adjusted to citizens’ demands. Cervantes et al. (2018) observes that a geographical region offers unique information to facilitate integration that makes MSW beneficial, consistent and applicable in different areas. In this context, it is important to understand MSWM in each geographic area to obtain generalizability. A comparison study with deeper recognition of local issues is necessary. Hence, this study aims to compare such MSWM strategies among the major cities of Vietnam, including Hanoi, Danang and Ho Chi Minh City. Further complexity is linked to practical difficulties in MSWM often characterized as a high volume of uncertain factors accompanied by conflicting expenses, benefits, and value assurances for influential stakeholders (Marshall and Farahbakhsh, 2013; Yadav et al., 2017). Soltani et al. (2015) confirm that decision-makers need decision support frameworks to determine the relevant attributes and find appropriate solutions. Arıkan et al. (2017) stated that MSWM contains a combination of multiple qualitative and quantitative attributes, which results in unreliable decision-making (Gambella et al., 2019). It is challenging to accurately perceive the complex problem of MSWM (Seng et al., 2011). As noted above, linguistic references have been neglected in the decision-making process, which fail to address the interrelationships among the proposed attributes. This study adopts the fuzzy decision-making trial and evaluation laboratory (DEMATEL) to identify such MSWM strategies by going beyond experts’ linguistic references. The qualitative information is converted into crisp values for visual analysis, and the causal relationships among attributes are examined (Wu et al., 2015; Tseng et al., 2017a, 2017b). Additionally, an exploratory factor analysis (EFA) is conducted to confirm the construct validity and reliability of the created hierarchical model (Tseng and Bui, 2017). The study objectives are as follows:

2. Literature review This section discusses the MSWM and technical integration literature as well as measurement attributes and proposed methods. 2.1. Municipal solid waste management Prior study describes MSWM as a complex procedure comprising waste gathering procedures, transfer station positions, treatment approaches, energy recovery, and treatment plant locations (Dewi et al., 2010). The goal is to balance waste management activities with the TBL to include environmental effectiveness, social acceptability, and economic affordability (Morrissey and Browne, 2004). Sharholy et al. (2008) claimed that efficient MSWM requires support from both the authorities and citizens, with the latter being individuals with evolving community awareness and societal interest. Guerrero et al. (2013) showed that an effective system should recognize environmental, sociocultural, and economic bonds to facilitate facilitate effective MSW for the entire system. Yu and Solvang (2017) showed that addressing environmental goals based on the proportion of treated MSW and number of residents exposes room to tighten MSW with environmentally friendly and sustainable solutions. Meanwhile, abandoned or incorrect MSWM leads to serious problems, including harm to social welfare, ecosystem damage, and biodiversity loss, in addition to economic consequences (Sisto et al., 2017). Poor MSWM performance creates serious threats to the environment and residents’ wellbeing, particularly when waste is inappropriately deposited near highly populated areas, water supplies, and sewage systems (Coban et al., 2018a, 2018b). Solid waste volume is growing due to population growth, economic development, urbanization and industrialization, which have been increasing consumption rates, resulting in MSW generation (United Nations Environment Programme (UNEP, 2009; Henry et al., 2006). MSW refers to waste in a solid form as produced in daily activities by households and industrial, commercial, and institutional establishments, for example, waste from hotels, offices, stores, schools, institutions and supermarkets and from public services such as hospitals, markets, yards, entertainment venues, and street cleaning (Ngoc and Schnitzer, 2009; Yukalang et al., 2017). Su et al. (2007) argued that because the consequences of MSW are becoming more complicated, MSWM presents an escalating problem, as it is challenging for municipal authorities to guarantee effective and sustainable waste management. Guerrero (2013) noted that governments’ capabilities are limited in managing waste, contributing routinely inefficient and insufficient MSW. There is a need to involve the strategies that have been able to achieve the goals of MSWM: human health, environmental protection, economic improvement, and social welfare satisfaction (Soltani et al., 2015). A sustainable MSWM system needs to be implemented that comprehensively considers the TBL perspectives to avoid short- and longterm negative impacts on the ecosystem and public health (Tan et al., 2014). Morrissey and Browne (2004) suggested that the system should not only be environmentally efficient and economically reasonable but also socially adequate. Pires et al. (2011) stated that sustainable MSWM is essential to all stages of the system from planning to design, procedure and decommission to retain current environmental quality and to meet future sustainability goals. However, because MSWM is complex and unified, it involves multiple TBL perspectives. To confront such challenges in practice, municipalities need fast reactions and effective instruments for appropriate decision-making that satisfies the current circumstances (Coban et al., 2018a, 2018b). An integrated system is necessary to address the development of MSWM by supporting the many operating, functioning and management decisions around waste

• To develop a set of MSWM attributes those are valid and reliable. • To identify the attributes of cities in Vietnam under uncertainty. • To present practical criteria for each city and offer a comparison. The contributions of this study are (1) examining and structuring an extended MSWM model; (2) presenting a set of attributes to assist practitioners by enhancing the decision-making process ;and (3) providing suitable practical guidelines to help communities and government agencies achieve sustainability. The rest of this study comprises five sections. Section 2 addresses MSWM, the technical integration literature, measurement attributes and proposed methods. The following two sections present the case background of three cities, including the methods, detailed analysis steps, and the study results. Section 5 2

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treatment and discarded components, the selection of waste treatment technology and waste stream allocation for disposal facilities and landfills (Asefi and Lim, 2017).

Table 1 Attributes. Criteria

2.2. Technical integration for MSWM By technical integration, this study refers to an integrated solid waste management system, which requires the selection and application of suitable engineering, technology and administration agendas to achieve management objectives (Kemirtlek, 2010). An integrated system provides solutions through systematic enquiry that reflects the need to address problems from different MSWM perspectives (Arıkan et al., 2017). Zaman (2014) integrated MSWM is used to analyze performance and make comparisons between municipalities or technologies to support decisions that deliver beneficial environmental, social, economic, and political impacts in practice. Asefi and Lim (2017) found that complete systems are necessary for waste minimization, collection, decomposition, recycling and disposal to solve the growing challenges of MSWM because there is increasing complexity driven by a growing number of related factors. In other words, MSWM is a complex task that requires suitable technical clarification, adequate managerial capability, and cooperation among stakeholders to ensure sustainable development (Zarate et al., 2008). At the municipal level, solid waste management is more rigorous in addressing technical issues and entails more information on costs, workforce, performance, the variety of waste types, and ecological education and training (Cervante et al., 2018). The municipality is one of the most frequently evaluated levels in MSWM (Cervante et al., 2018). Robins (2008) noted that MSWM is achieved through social, economic and institutional dimensions and through technical capacity, including adequate infrastructure, achieved through implementation by municipal authorities. Marino et al. (2018) linked the TBL to the technical dimensions for enhancing MSWM administrative capacity. Pires et al. (2011) claimed that there is a need to enable technical integration to handle the complexity of multiple goals, risks and uncertainties for decision-making. Hence, technical integration is implemented in this study to incorporate the interrelated procedures in the waste management chain (Marshall and Farahbakhsh, 2013).

References

C1

Community concerns

C2 C3 C4

Legislation and policies Stakeholders' involvement Institutional and organizational administration framework Occupational safety and health Resources efficiency Pollution standardization. Environmental mitigation Financial and operational requirements City parameters Economics benefit Facilities and infrastructure requirement Waste treatment innovative capacity Technology functionality and appropriateness

C5 C6 C7 C8 C9 C10 C11 C12 C13 C14

Henry et al., 2006; Marshall and Farahbakhsh, 2013; Coffey and Coad, 2010 Marino et al., 2018 Zurbruegg, 2003; Marshall and Farahbakhsh, 2013. Alli, 2008; Cervantes et al., 2018 Deus et al., 2019; Zaman, 2014 Shekdar, 2009 Ikhlayel, 2018 Cobbinah et al., 2017 Guerrero et al., 2013 Ikhlayel, 2018 Guerrero et al., 2013 Fernando, 2019 Deus et al., 2019

et al., 2018). The hybrid method of EFA and fuzzy DEMATEL method is appropriate for measuring the MSWM framework and constructing correlations between the aspects and criteria of MSWM in this study. 2.4. Proposed measures MSWM has become a major topic because it influences economic development as well as environmental protection and public health (Soltani et al., 2015). Marshall and Farahbakhsh (2013), a sustainable MSWM system requires the three TBL perspectives to be balanced. However, to overcome problems in practice, a more comprehensive assessment should be considered. This study proposes a set of attributes that consist of 4 aspects, including social acceptability, environmental benefits, economic sufficiency and technical integration, and 14 criteria (listed in Table 1). The criteria presented within social acceptability comprise community concerns, legislation and policies, stakeholders' involvement, institutional and organizational administration frameworks, and occupational safety and health (Marshall and Farahbakhsh, 2013; Cervantes et al., 2018). Community concerns (C1) refer to people’s awareness, willingness to pay for waste management services, protection of proposed waste facility locations, waste utilization methods, and opinions regarding the success or failure of MSWM (Marshall and Farahbakhsh, 2013; Henry et al., 2006). Legislation and policies (C2) are essential for MSW practices, aiming for regulatory execution of an appropriate MSWM strategy with a straightforward, clear outline, active assessment and applicable processes (Coffey and Coad, 2010). Stakeholders’ involvement (C3) reflects the accomplishment of activities such as providing waste management knowledge, contractual problems, regulatory implementation, recreational tasks, fundraising associated with developing the system for an effective sustainable economy and the social management and control of the entire process (Marino et al., 2018). Last, the institutional and organizational administration framework (C4) describes the decentralization level, distribution of authority, and responsibilities of the municipalities (Zurbruegg, 2003). These social criteria are responsible for how MSWM authorities cooperate with others, such as the private sector and community groups, and for the administrative processes of scheduling and supervision as related to current and future legislation (Marshall and Farahbakhsh, 2013). Occupational safety and health (C5) is described as safety controls that in the workplace to protect waste workers’ health and wellbeing, as they are highly exposed to heavy workloads, hazardous materials and even potentially contagious materials that could infect the surrounding communities and the environment (Alli, 2008; Cervantes et al., 2018).

2.3. Proposed method This study applies the fuzzy DEMATEL method to assess experts’ linguistic references in the context of MSWM. MSWM is a complicated and integrated process involving complex quantitative and qualitative problems, and this method provides the necessary support for including relevant attributes and their weights in the applicable decision-making activities (Coban et al., 2018a, 2018b). In particular, fuzzy set theory has been applied to quantify the qualitative perceptions stemming from human linguistic judgments with uncertainty, while the DEMATEL method aims to analyze the structure of causal interrelationships among complex attributes (Wu and Lee, 2007). Wu et al. (2017) adopt fuzzy DEMATEL to investigate causal interrelationships among attributes for optical examinations. Tseng et al. (2018) revised the qualitative linguistic descriptions provided by experts to create a causal illustration of interdependent attributes by applying fuzzy DEMATEL. The attributes’ distribution is identified based on the driving and dependent powers among them. However, only a few studies have addressed the disadvantages of construct validity, the reliability of the proposed hierarchical framework and the qualitative data (Tseng et al., 2017a, 2017b). To address these problems, an EFA technique is proposed to investigate the direct or indirect interrelationships among attributes and to construct a valid and reliable hierarchical framework (Su et al., 2015, Tseng et al., 2015). This technique is used to group the criteria into a multilevel framework obtained from important evaluations of observed criteria that are assume to have linear relations to the proposed aspects (Tseng 3

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country generates over 15.6 million tons of solid waste annually, and this amount has been increasing by 10–16 % annually. In municipal areas, considering total waste, the ratio of solid waste for landfills is approximately 34 %, waste minimized or recycled at a treatment plant is approximately 42 % and the remaining solid waste represents improperly disposed waste from the disposal process and accounts for approximately 24 %. General waste treatment methods are popular, such as landfilling, composting and burning. However, these methods cannot be considered to be suitable treatment techniques for solid waste due to their unpredictable environmental consequences. The environmental problems caused by solid waste often result from improper management of solid waste from the source of origin to the final disposal site. A well-organized, operating and effective MSWM municipal system that reduces costs and limits environmental problems is required. Municipal authorities urgently need appropriate MSWM strategies to support their decision-making framework. The amount of MSW generated depends on the size of the urban population and has different characteristics depending on the geographical area and socioeconomic features. MSWM strategies must distinguish critical features to protect human health and the environment and conserve resources. Further, each municipal level will have unique requests for the waste treatment process to fit with municipal and policy goals. The priority given to MSW problems varies widely based on the living standard of the focal area (Cervantes et al., 2018). This study intends to investigate these differences by comparing the MSWM strategies of three major cities in Vietnam: Hanoi, Danang and Ho Chi Minh City. These cities are located in three different regions and have dissimilar socioeconomic characteristics. Specifically, Hanoi and Ho Chi Minh City are special because the first is Vietnam’s capital and is located in the north, and the second is the largest city in Vietnam and is located in the south. Danang city represents a third type of city and is located on the central coast of Vietnam. The geographic characteristics of the three cities are shown in Table 2.

Generally, safety involves the decision-making procedure for consumption and disposal behavior. This study aims to identify environmental benefits to favorable MSWM that help achieve a sustainable system (Zurbrügg et al., 2012). Sustainability may always be a challenge because the community continues to create more waste due to population expansion and the need to achieve modern advancements (Ikhlayel, 2018). Environmental processes may lead to sustainable utilization, in which resource efficiency (C6) reflects the quantity of resources that are recuperated from waste streams and used as a substitute for new materials, which contributes to the alternatives to water, energy, and emissions in MSWM systems (Deus et al., 2019; Zaman, 2014). Pollution standardization (C7) is confirmed to minimize the environmental pollution of the links in the MSW chainand improve reclaimed site usage (Shekdar, 2009). As a result, environmental impact mitigation (C8) is achieved (Ikhlayel, 2018). Mitigation minimizes environmental consequences by highlighting deterrence, reuse, recycling, and recovery over landfills (Cobbinah et al., 2017). Economic sufficiency has drawn attention to MSWM (Henry et al., 2006; Arıkan et al., 2017). City parameters (C9) refer to the factors of municipal infrastructure, environment interest, local knowledge, and cooperation and coordination between services providers and their clients, leading to the efficiency of municipal management (Guerrero et al., 2013). In addition, substantial spending is required to deliver the service (Sharholy et al., 2008). Financial and operational requirements (C10) in terms of capital and recurrent costs are taken from public revenues, and cost recovery is necessary from households and institutions paying for waste management services (Cobbinah et al., 2017). In contrast, economic benefits (C11) are an essential component of the integrated level, which mainly concentrates on reducing cost and generating more revenue to create business and employment opportunities. Nevertheless, a deficiency of sponsorship, limited resources, the reluctance of service users to pay and the absence of appropriate economic direction have weakened the MSWM system (Ikhlayel, 2018). The criteria must be considered to identify MSWM strategies. Prior studies have proposed that there are technical issues influencing the system related to facilities and infrastructure, capacity for innovative waste treatment, and the functionality and appropriateness of provided technology (Deus et al., 2019; Guerrero et al., 2013). These criteria represent drivers towards the archetype of integrated MSWM. The facilities and infrastructure requirement (C12) is necessary for waste collection, allocation and transport, and enhancing these has positive effects on system efficiency (Guerrero et al., 2013). Capacity for waste treatment innovation (C13) is described as acquiring the methods needed to achieve a sustainable MSW treatment process and encourage MSWM regulatory accomplishments (Fernando, 2019). Furthermore, providing technological functionality and appropriateness (C14) advances inter-municipal waste management coordination, advocates benchmarks for active analysis and fosters an appraisal record that encompasses incidental practical and functioning occupations and competences (Deus et al., 2019). There is a need for decision-makers to be aware of the municipal situation to make beneficial adjustments and improve MSW technical integration strategies to adapt to the citizens’ demand.

3.2. Exploratory factor analysis EFA is a statistical reduction method that is used to identify variables (calls aspects in this study) that describe a tendency towards correlation in a group of observed variables (criteria) and rearranges these variables into a more relevant set (Adabre and Chan, 2019). The Kaiser-Meyer-Olkin (KMO) value and Bartlett’s test of sphericity are obtained to identify the construct’s appropriateness. While the KMO compares the partial correlation coefficient size to determine the sample adequacy, Bartlett’s test of sphericity checks for the presence of correlation within the set of variables (Kaiser, 1974). The factor loading calculated is to ensure that the EFA reaches a level of practical significance. In addition, the internal consistency of the value construct is tested using Cronbach’s alpha; when the Cronbach’s alpha exceeds 0.7, it indicates that the set of variables has acceptable reliability. Therefore, EFA procedures precisely measure the reliability and validity of each aspect when representing multiple criteria in the analytical process (Amerioun et al., 2018; Tseng et al., 2017a, 2017b). This study applies this technique to confirm the hierarchical framework’s reliability and Table 2 Cities’ geographic characteristics. Sources: Vietnam environmental monitoring portal (2019), General statistics office of Vietnam (2019)

3. Method This section presents the MSWM in Vietnam and discusses the EFA and fuzzy DEMATEL. In addition, the steps for the evaluation process are proposed.

2

Area (km ) Population (millions of people) Population density (people/km2) Amount of MSW/year (tons) Collection rate MSW increasing rate/year

3.1. Case background The volume of MSW is increasing rapidly in proportion with population growth and socioeconomic development. According to the Vietnam Center for Environmental Monitoring portal (2019), the 4

Hanoi

Da Nang

Ho Chi Minh City

3 324.92 8.215 2 505 2 737 500 87 % 15 %

1 285 1.064 828 365 000 82 - 85 % 8- 9 %

2 061.04 8.859 4 097.2 3 175 500 100 % 7-8 %

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validity.

matrix by applying the following equations.

3.3. Fuzzy DEMATEL

γ= [∑ wij]n×n = [wi]n×1

n

(7)

i−1

The fuzzy DEMATEL translates human judgments into fuzzy linguistic scales. Crisp values are converted from fuzzy numbers using the defuzzification method from fuzzy set theory. The fuzzy minimum and maximum numbers transform the fuzzy data into crisp values to calculate the left and right numbers (Opricovic and Tzeng, 2004). Next, k ∼k ∼k e kij = (∼ e 1ij , e 2ij, e 3ij) is utilized the mean weight of the fuzzy affiliation ∼ to summarize the weighted values. Then, the total direct relation matrix is adjusted from the crisp value. A visual diagram is generated by DEMATEL to present the analytical results, and the problems are simplified by categorizing the attributes into a final diagram that describes their interrelationships and the influential effects among them. These groups provide a better structure for evaluating the interrelationships among the attributes. The DEMATEL is used to solve complex interrelationship problems (Gabus and Fontela, 1972; Wang and Chuu, 2004). The interrelationships between attributes are generated by the DEMATEL. If a system is collected for a set of attributes, F= {f1, f2, f3, ⋯, fn} , specific pairwise interrelations are adopted to classify the mathematical relationship. The comparison scale is into five linguistic references: VL (very low influence), L (low influence), M (moderate influence), HI (high influence) and VHI (very high influence) (see Table 2) to calculate the fuzzy direct relation matrix between attributes. Assume that there are k members included in the decision e kij , which denotes the fuzzy weight of the group performing valuation ∼ ith attribute affecting the jth attribute assessed by the kth expert. The corresponding fuzzy numbers are normalized:

n

δ= [∑ wij]n×n = [w]j 1 ×n A causal interrelationship diagram is obtained by locating the attributes with (γ+ δ), (γ− δ) . [(γ+ δ), (γ− δ)] , in turn, represent the horizontal and vertical axes, and a cause-and-effect diagram is drawn. (γ+ δ) addresses the importance of attributes, and a higher value of (γ+ δ) indicates that the attribute has a more important function than the others. For the aspect, (γ− δ) enables grouping the attributes into cause-and-effect groups by considering (γ− δ) as positive or negative. γ is the summary value of rows, and δ presents the summary value of columns. If ( γ− δ ) is positive, the aspects are characterized as cause groups; otherwise, they are effect groups. For the criteria, a visual diagram is mapped based on the driving and dependent powers. The arrangement is mapped onto four quadrants, defined as an autonomous quadrant with weak driving and dependent power, a dependent quadrant with weak driving power but strong dependent power, an independent quadrant with weak dependent power but strong driving power, and a linkage quadrant with both a strong driving and a strong dependent power (Tseng et al., 2018) 3.4. Proposed steps This study implements the following steps of the hybrid method for examining MSWM attributes and conducts the analysis. Step 1. The MSWM are collected from the literatures, and a group of 36 experts with more than 8 years of experience in the field of MSWM from academic, institutional, and practical operations, including 12 experts from Hanoi, 12 experts from Danang and 12 experts from Ho Chi Minh city, are consulted to verify the attributes and study framework. The questionnaires are provided for the experts to address their linguistic preference towards the attributes. Step 2. The linguistic data are translated into TFNs. Next, these numbers are converted into comparable values, and the fuzzy valuations are defuzzified using Eqs. (1)–(3). Step 3. EFA is applied to assemble the criteria into a hierarchical framework and test the validity and reliability of the framework structure. The decision matrix is computed using Eq. (4). The data is analyzed using SPSS 25.0 software. Step 4. The crisp values are utilized to generate the total DEMATEL relation matrix with Eqs. (5)–(8). The causal effect diagram is obtained (Table 3).

∼k , fe ∼k , fe ∼k ) F= (fe 1ij 2ij 3ij k k k k k k ⎡ (e1ij − mind1ij) (e2ij − mine2ij) (e3ij − mine3ij) ⎤ , , =⎢ ⎥ Δ Δ Δ ⎣ ⎦

k maxe3ij

(1)

k mine1ij

− where Δ = Next, the left (lv) and right (rv) are transformed into normalized values (Eq. 2) to generate the total normalized crisp values (Eq. 3): k k (fe2ij fe3ij ⎤ ⎡ , (lv nij , rv nij) = ⎢ k k k k ⎥ (1 fe fe ) (1 fe fe ) + − + − 2ij 1ij 3ij 2ij ⎦ ⎣

cv kij =

(2)

[lv kij (1 − lv kij) + (rv kij)2] (1 − lv kij + rv kij)

(3)

Next, this study adopts the synthetic value representation to gather the individual judgment of k experts.

(cv 1ij + cv 2ij + cv 3ij+⋯+cv 3ij) ∼ e kij = k

4. Results (4) The EFA and fuzzy DEMATEL results are reported in this section. In addition, the MSWM differences between cities are described.

The initial direct relation matrix (IM) is a n× n matrix obtained by e kij signifies the level to which pairwise comparisons. In this matrix, ∼ ∼k ] . attribute i affects attribute j, which is modified as IM= [e ij n×n The normalized direct relation matrix (U) is created.

τ=

4.1. EFA result

U=τ⊗IM 1 max 1 ≤i≤k

e kij ∑ j= 1 ∼

Bartlett's test is significant (p < 0.05), and the KMO value exceeds

k

Table 3 TFNs linguistic scale.

(5)

The total interrelationship matrix (W) is obtain from the normalized direct relation matrix with assistance from the equation below.

W= U(I− U)−1

(8)

j−1

(6)

where W refers to [wij]n×n i, j= 1,2, ⋯n Finally, the driving power (γ) and dependent power (δ) are gathered from the total for the rows and column values in the total relation 5

Scale

Linguistic variable

Corresponding triangular fuzzy number (TFNs)

VL L M H VH

Very low influence Low influence Moderate influence High influence Very high influence

(0.0, (0.1, (0.3, (0.5, (0.7,

0.1, 0.3, 0.5, 0.7, 0.9,

0.3) 0.5) 0.7) 0.9) 1.0)

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(γ− δ ) values. Fig. 2 shows that there are differences between cities in terms of environmental benefits (A2) and economic sufficiency (A3), which are emphasized in Hanoi and underestimated in Danang and Ho Chi Minh city. By contrast, economic sufficiency (A3) is emphasized in Hanoi city but has not been a focus in the other two cities. Specifically, Danang city shows a dramatic gap, as economic sufficiency (A3) is low driving and important power. In both cases, technical integration (A4) is indicated as the strongest cause aspect in MSWM The cause-and-effect interrelationships among the criteria are presented in Table 9 by repeating the analytical procedure. The generated driving and dependent power diagram is shown in Fig. 3. The diagram divides the criteria into four quadrants, as described above. Specifically, the autonomous quadrant includes criteria that are rather disconnected from the system, in that they show a very limited effect on others. The dependent quadrant includes criteria that have less effect on the system and that are easily influenced by other criteria. The criteria in the independent quadrant are similar; even though they display considerable driving power, they are still less related to the framework. The last quadrant presents the linkage criteria, which substantially affect other criteria and have continuing effects within the framework and response effects by enhancing other criteria. The criteria belonging to the linkage quadrants are counted as the most urgent criteria requiring focus. These criteria are distinct between cities. The linkage criteria for Hanoi city include the institutional and organizational administration framework (C4), occupational safety and health (C5), economic benefits (C11), and technology functionality and appropriateness (C14). Danang city has the criteria of occupational safety and health (C5), resource efficiency (C6), waste treatment innovation capacity (C13) and technology functionality and appropriateness (C14) linking the MSWM together. For Ho Chi Minh City, the linkage groups are financial and operational requirements (C9), economic benefits (C11), facilities and infrastructure requirements (C12), and waste treatment innovation capacity (C13). In general, occupational safety and health (C5), economic benefits (C11), waste treatment innovation capacity (C13), and technology functionality and appropriateness (C14) are the most important criteria for improving the overall MSWM system. The criteria differences between cities are presented in Fig. 4. The graph shows that concerns for practicing MSWM in Danang and Ho Chi Minh are similar because the series of criteria in each city is practically parallel. However, there are points that should be further investigated. The financial and operational requirements (C9), city parameters (C10) and economic benefits receive excessive focus by Danang and Ho Chi Minh City authorities despite these criteria receiving less focus from Hanoi municipalities. Ho Chi Minh City shows weakness in legislation and policies (C2). The results additionally provide information on a level of considerations cities give the MSWM system of each municipality. Ho Chi Minh City has the greatest strategic concern with MSWM

Table 4 KMO and Bartlett's Test. Kaiser-Meyer-Olkin Measure of Sampling Adequacy

0.659

Bartlett's Test of Sphericity

Approximate Chi-Square Degree of freedom Significant

481.113 91 0

0.5, which confirms that the crisp value used to convert experts’ linguistic references is appropriate for the factor analysis (Kaiser, 1974) (see Table 4). Factor loading higher than 0.5 is regarded as significant and indicate the validity of the criteria (Li et al., 2011). Next, the reliability of each aspect group is confirmed with Cronbach’s alpha values, which exceed 0.7, including social acceptability (α= 0.957 ), environmental benefits (α= 0.854 ), economic sufficiency (α= 0.907 ) and technical integration (α= 0.934 ). These results indicate that the study hierarchical framework is valid and reliable (Table 5). 4.2. Fuzzy DEMATEL results The experts’ linguistic reference to the aspects’ interrelationships is converted into TFNs based on the linguistic scale from very low influence to very high influence, as shown in Table 6. The TFNs are normalized as crisp values (see Table 7) with incomparable and incomputable features, which require a synthetic value notation to obtain the exact crisp value (see example in Table 7). These values are placed into an interrelationship matrix and aspect grouping to inspect the interrelationships as well as the driving and dependent powers through a cause-and-effect diagram. This matrix is transformed into causal interrelationships, as shown in Table 8. A cause-and-effect diagram is mapped beyond the dataset of [(γ+ δ), (γ− δ)]. The results show that there are differences in the causeand-effect aspects between cities (see Fig. 1). For Hanoi city, social acceptability (A1), economic sufficiency (A3), and technical integration (A4) are the causal aspects that have impacts on environmental benefits (A2) in the effect groups. For Danang city, the cause group includes social acceptability (A1) and technical integration (A4), and the effect group includes environmental benefits (A2) and economic sufficiency (A3). For Ho Chi Minh City, economic sufficiency (A3) and technical integration (A4) are causal aspects, while social acceptability (A1) and environmental benefits (A2) are the affected aspects. Overall, social acceptability (A1) and technical integration (A4) are categorized in the cause group, and environmental benefits (A2) and economic sufficiency (A3) belong to the effect group. In particular, technical integration (A4) shows the strongest effect level for the interrelationships among the aspects. A graph comparing aspects of the cities is drawn from the (γ+ δ) and Table 5 Exploratory factor analysis and reliability test. Aspects

Criteria

A1

Social acceptability

A2

Environmental benefits

A3

Economic sufficiency

A4

Technical integration

C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 C13 C14

Community concerns Legislation and policies Stakeholders' involvement Institutional and organizational administration framework Occupational safety and health Resources efficiency Pollution standardization. Environmental mitigation Financial and operational requirements City parameters Economics benefit Facilities and infrastructure requirement Waste treatment innovative capacity Technology functionality and appropriateness

6

Factor loading

Cronbach alpha (α )

0.959 0.949 0.945 0.959 0.950 0.952 0.659 0.982 0.973 0.917 0.863 0.942 0.958 0.922

0.957

0.854

0.907

0.934

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Table 6 Transferred TFNs for aspects. A1 A1 A2 A3 A4

[1.000 [0.700 [0.300 [0.700

1.000 0.900 0.500 0.900

A2 1.000] 1.000] 0.700] 1.000]

[0.500 [1.000 [0.500 [0.300

A3

0.700 1.000 0.700 0.500

0.900] 1.000] 0.900] 0.700]

A1 A2 A3 A4

A2

A3

A4

0.695 0.508 0.523 0.574

0.592 0.678 0.503 0.602

0.533 0.491 0.690 0.515

0.515 0.528 0.517 0.751

0.900 0.700 1.000 0.700

1.000] 0.900] 1.000] 0.900]

[0.700 [0.700 [0.700 [1.000

0.900 0.900 0.900 1.000

1.000] 1.000] 1.000] 1.000]

suitable for municipal conditions, simultaneously building infrastructure for solid waste sorting, collection, transportation, treatment and recycling activities to boost and promote the efficiency of MSWM. Good technical integration can foster socioeconomic development and environmental protection. Social acceptability (A1) is recognized as one of the cause aspects of MSWM, confirming that the participation of the community, NGOs, government partners and local businesses responsible for public service duties is necessary, as cooperation and shared contributions are required to ensure sustainability. This aspect requires active support from both the municipal agency and citizens, and community awareness and societal interest should be encouraged to evolve for operational efficiency (Sharholy et al., 2008). Problems arise from both the community and the municipal authorities. In areas with a high population, in particular, low awareness of MSWM and public sanitation means that people still think that waste management is the responsibility of only the authorities. For this reason, it is urgent to increase awareness and the capacity of the community to understand their rights and obligations in waste management. Often, the participation of the local community and community-based organizations is combined to organize and operate MSWM systems, educate the public about consumption and disposal behavior and engage in decision-making processes to support solid waste minimization. Economic sufficiency (A3) is an essential aspect of MSWM. Given the economic advantages, the municipal authorities can condense the system of waste causes, materials, and treatment solutions, forecast market trends, and increase flexibility to decrease environmental influences while driving costs down, continually expanding recovery areas; developing contracts; completing regulations; and raising funds for effective MSWM sustainability (Marino et al., 2018). Economic sufficiency is inferred to be the use of economic tools to simultaneously form and develop all types of markets for goods and services using recycled products by considering waste as a commodity that is exploited to generate revenue and profit for related organizations. Economic sufficiency will help balance the benefits with the costs, ensuring the goal of waste management with the lowest cost to society. This aspect plays a critical role in financial support for developing recycling infrastructure, concerns about recycling in rural areas, transportation, collection centers and organizations (Henry et al., 2006; Sharholy et al., 2008). Economic sufficiency can create financial savings for businesses, citizens and the government; it helps to reduce resource use and the cost of waste disposal and to form an MSWM system that brings environmental benefits, positive social impacts and enhances the sustainable performance of municipal areas. This study supports the sustainable development of urban regions based on a dialectical interrelationship between MSWM aspects to

Table 7 Crisp values for aspects. A1

[0.700 [0.500 [1.000 [0.500

A4

among the cities, followed by Hanoi, whereas Danang city gives the least attention to MSWM. 5. Implications The theoretical and practical implications are discussed in this section. The differences between cities are explained, and the proposed for practical MSWM operation is presented. 5.1. Theoretical implication This study has contributed to the literature by confirming a hierarchical framework that emphasizes the significant role of TBL perspectives in enhancing MSWM sustainability and confirms the influence of technical integration on MSWM in practice. In detail, technical integration (A4) and social acceptability (A1) are the two aspects that drive the MSWM, as they are the most frequently appraised (Cervantes et al., 2018). Likewise, although economic sufficiency (A3) is considered to be one of the affected groups in the overall scenario (Fig. 4), it still must be noted that it is a critical aspect beyond the city’s control (Figs. 1 and 3). These aspects should receive special attention due to their role in the framework. The results show that technical integration (A4) is the most important aspect because it drives the TBL and has a strong effect on environmental benefits. This aspect is confirmed as an efficient solution for solving the inconsistent TBL perspectives and moving towards sustainability (Heidari et al., 2019). Correlating technical integration with the TBL can enhance MSWM administrative capacity and enforce positive environmental, economic, social and political effects in practice (Marino et al., 2018; Zaman, 2014). However, inappropriate technical integration might lead to environmental pollution, and public health impacts determine unsustainable MSWM. The municipal level deals more intimately with the technical aspects and entails more specific expenses, performances requirements, workforce needs, ecological requirements, or various waste issues (Cervantes et al., 2018). Therefore, it is important for municipalities to select and develop technical plans Table 8 Interrelationship matrix and cause-and-effect interrelationship among aspects. Hanoi

A1 A2 A3 A4

Da Nang

HCMC

Overall

γ

δ

γ+ δ

γ− δ

γ

δ

γ+ δ

γ− δ

γ

δ

γ+ δ

γ− δ

γ

δ

γ+ δ

γ− δ

17.930 15.821 17.417 18.453

16.277 17.250 16.273 17.105

34.207 33.070 33.689 35.558

1.653 (1.429) 1.144 1.348

17.509 16.812 15.236 18.010

16.277 17.250 16.273 17.105

33.786 34.061 31.509 35.115

1.231 (0.438) (1.036) 0.905

15.551 15.305 15.937 17.042

15.937 16.174 15.332 16.392

31.487 31.480 31.269 33.434

(0.386) (0.869) 0.605 0.650

17.000 16.015 16.235 17.861

16.277 17.250 16.273 17.105

33.277 33.265 32.508 34.966

0.722 (1.234) (0.038) 0.756

7

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Fig. 1. Cause-and-effect diagram for cities and overall benchmark.

Fig. 2. Aspects comparison among cities.

affecting the surrounding environment. Hence, improving waste treatment innovative capacity (C13) is an urgent goal for cities that must be quickly achieved to minimize environmental pollution. However, the application of the relevant technology requires high investment, which is the biggest barrier driving municipal authority to lose interest in investing in this field. With the current quality of solid waste, all economic sectors participates in improving waste treatment innovative capacity are required to select treatment technology that can ensure investment profits and environmental efficiency. Change is needed in designing and constructing the MSWM control mechanism to attract investment resources for waste treatment projects with high technological applications. The government is encouraged to amended the regulations that make it difficult for other stakeholders (private contractor, NGOs, communities) to join in MSWM. A transparent and public invitation is recommended to select investors with advanced technology for waste treatment. The municipalities affirmed that the relevant departments and agencies are instructed to propose

generate gradual improvements towards building a complete waste management system. As a result, the MSWM becomes more efficient in terms of both waste generated and how waste is treated. 5.2. Practical implications The actual conditions for improving the efficiency of practices will be discussed in this subsection. Generalizing the overall scenario for MSWM confirms that occupational waste treatment innovative capacity (C13), safety and health (C5), economic benefit (C11), and technology functionality and appropriateness (C14) are the linkage criteria that act as strategic factors with strong connections to improve the performance of the whole system. MSW volume is dramatically increasing, causing many difficulties in treatment and thereby creating hard-to-avoid consequences, such as stench, air pollution, and high levels of vermin. This has revealed many limitations with the current methods of waste management that are 8

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Table 9 Interrelationship matrix and cause-and-effect interrelationship among criteria. Hanoi

C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 C13 C14

Da Nang

HCMC

Overall

γ

δ

γ+ δ

γ− δ

γ

δ

γ+ δ

γ− δ

γ

δ

γ+ δ

γ− δ

γ

δ

γ+ δ

γ− δ

13.359 13.771 12.769 14.440 14.423 12.933 13.475 13.078 12.052 13.726 14.264 13.874 14.756 14.405

13.352 13.130 13.386 13.775 14.264 13.850 12.799 14.296 13.481 14.440 13.080 12.692 15.016 13.765

26.711 26.901 26.155 28.215 28.687 26.783 26.274 27.374 25.533 28.166 27.344 26.566 29.772 28.170

0.007 0.641 (0.617) 0.665 0.160 (0.916) 0.676 (1.218) (1.429) (0.713) 1.184 1.181 (0.260) 0.641

10.136 11.155 10.953 11.035 11.755 10.999 9.852 10.065 10.853 10.869 10.904 10.454 11.992 11.662

9.555 11.248 10.486 11.057 11.416 10.867 10.914 10.607 11.409 10.771 11.256 10.613 11.471 11.014

19.690 22.404 21.440 22.092 23.171 21.866 20.766 20.672 22.262 21.640 22.159 21.067 23.463 22.675

0.581 (0.093) 0.467 (0.022) 0.339 0.132 (1.061) (0.543) (0.556) 0.098 (0.352) (0.159) 0.520 0.648

14.820 13.764 14.946 14.758 14.869 14.108 14.171 13.994 15.065 14.957 15.031 15.119 15.784 14.409

15.147 14.934 14.186 16.019 15.084 15.259 13.208 15.525 14.975 13.648 14.770 14.668 14.705 13.667

29.967 28.698 29.132 30.777 29.953 29.367 27.379 29.520 30.040 28.605 29.800 29.786 30.489 28.076

(0.326) (1.170) 0.760 (1.261) (0.215) (1.151) 0.963 (1.531) 0.089 1.308 0.261 0.451 1.079 0.742

12.413 12.659 12.620 13.090 13.424 12.435 12.135 12.057 12.409 12.878 13.070 12.797 13.880 13.256

12.267 12.845 12.379 13.268 13.290 13.000 12.105 13.109 13.026 12.671 12.783 12.368 13.443 12.569

24.680 25.504 24.999 26.357 26.714 25.435 24.240 25.166 25.434 25.548 25.853 25.165 27.323 25.825

0.146 (0.186) 0.241 (0.178) 0.134 (0.564) 0.030 (1.052) (0.617) 0.207 0.287 0.429 0.438 0.686

Fig. 3. Driving and dependence power of the criteria for cities.

participation in the field of solid waste treatment. The results show that occupational safety and health (C5) is one of the main issues requiring high attention. Due to problems affecting the environment in municipal areas, such as leaked solid waste water, emissions from untreated landfills, environmental incidents and disease-causing insects, the municipal authority is necessary to create a unified, clear and standardized process for a safety and a healthy MSWM system. This study proposes to design a safety – health – environment management system as a strategic management program including protective equipment, guidelines for implementation, human resource development, and employee health care. Regular workers should receive health care training and education in coordination with the waste treatment enterprise and the urban environment agencies, which responsible for occupational safety. These agencies should improve environmental sanitation, equip staff with protective equipment,

periodic health care, and educational information. Additionally, communities should conduct waste separation at the source to separate MSW into biodegradable organic, recyclable and recyclable waste for safety collection processes. Economic benefits (C11) refer ways to treat waste so that it brings in profits and does not pollute the environment. This criterion considers waste as a valuable resource that is derives from one type of production and becomes the input material for another type of production. Improving economic efficiency through resource use, handling, and disposal and by creating a market for waste recycling can lead to the efficient production and consumption of products. However, this strategic criterion has not been achieved in practice because MSW has not been considered a valuable resource for secondary markets, such as the market for recycled products and energy. The confliction between economic benefits and environmental protection in localities has made 9

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Fig. 4. Criteria comparison among cities.

systems. Simultaneously, authorities should develop a management mechanism and policy to support the collection force and transform the operational model. It is necessary to speed up inspection and supervision, and after time has been spent guiding and reminding citizens. Applying sanctions on waste source owners, collectors and transporters who violate the regulations on waste separation becomes more necessary.

attempts to reduce pollution less effective than expected. Valuable waste materials should be directed to reuse to create new employment capabilities and business opportunities. The classification of solid waste brings many economic benefits by creating a clean material source for compost production, and recycled materials should be processed. For example, burning waste to become electricity or heat energy and processing organic waste into micro-organic fertilizer. Reducing or eliminating adverse impacts on the environment through reduction, reuse, recycling, and the exploitation of resources can provide not only improved environmental and social quality but also economic benefits. Technology functionality and appropriateness (C14) for MSWM is essential in terms of both cost and environmental issues. Choosing a waste treatment technology that is suitable for each locality is an urgent mission that not only contributes to environmental protection but also promotes socioeconomic development. Foreign technology is largely unsuitable due to different solid waste characteristics, weather and living habits, so Vietnam must to take the initiative to solve this problem. This driver of MSW has not been thoroughly resolved, and there are many shortcomings that must be improved to develop a new technology capable of being replicated. The urgent is that an appropriate technology need to be selected based on the features of waste to achieve sustainable MSWM. Vietnam has three main waste treatment technologies, all of which have high investment rates: technology for processing waste into organic fertilizer, fuel pellets or for burning. The burning technology has been evaluated and found to be workable and environmentally friendly. Nevertheless, solid waste cannot be burned by the traditional biomass burning method due to the mixture, high humidity and low heating components. The amount of waste burned accounts for only a small portion of the input fuel (mainly coal) required to turn the waste into energy. These technologies are not as effective as expected because waste has not been classified at the source, so that inputs are not satisfactory. For that reason, waste separation at the source is again the primary solution. Educating communities about waste separation is important. Awareness campaigns and training programs should be provided, especially targeting households and children, who have more influence on waste management

5.2.1. Hanoi city This study finds a distinction between cities. Apart from the abovementioned criteria, the cities still have different concerns regarding MSWM. Hanoi city focuses on its institutional and organizational administration framework (C4). The municipal authorities are responsible for planning and budgeting for MSWM programs to meet the development goals and are the owners of the infrastructure and facilities. Currently, the responsibility for planning and managing the MSW infrastructure has been decentralized and gradually equitized. With such fundamental institutional changes, it is unclear whether these authorities are capable of fulfilling their assigned roles and whether there are effective legal instruments to force them to continue. A number of policies have been issued, but implementation mechanisms and guiding documents are still lacking, leading to ineffective or inefficient implementation, reflected in a failure to meet the environmental targets. There are no appropriate sanctions to enforce socialization or privatization for the classification, collection, transportation and treatment of solid waste. This has led many local businesses to resist privatization, preferring instead to maintain the public utility companies and their monopoly in solid waste management. In a monopoly context, communities need to be protected by some form of independent regulation. Therefore, local policymakers should have reform programs to transfer responsibilities to decentralized management agencies. The current laws should regulate key issues for MSWM, including human resources, organizational structure, qualifications and technical guidelines. Encouraging the community to participate in MSWM and strengthening the role of the community in waste management is a necessary. The immediate challenge is to issue and 10

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tourism is becoming a key economic sector, creating an urgent need to improve MSWM. This study suggests that the city authorities should identify appropriate mechanisms to promote policies to develop solid waste treatment technology that could minimize waste burial, increase the recycling and reuse ratio, and encourage the proper application of MSW treatment technologies suitable to the local conditions. Further, they should strengthen and diversify their investment sources for waste management to ensure the operation and maintenance of built solid waste collection and treatment systems. It is necessary that they issue the necessary mechanisms, policies and solutions to promote the socialization of solid waste management and develop professional environmental organizations and businesses that operate in solid waste management. Authorities should pay special attention to decentralization and assignment of clear and specific responsibilities, specifically, strengthening the capacity of related management agencies. Last, they should strengthen the socialization of solid waste collection, transportation and treatment by mobilizing community, private and sociopolitical organizations to participate in MSWM activities to approach sustainability.

implement support mechanisms to give people the opportunity to participate in community-based waste management models. The city shows less focus on financial and operational requirements (C9), economic benefits (C11) or important evaluations of city parameters (C10) than the other cities. This is because Hanoi is not in a position to build transfer stations or waste collection and transfer points; local plans lack waste treatment zones to reduce the treatment load for the city’s solid waste treatment areas. This demonstrates that the MSWM in Hanoi is facing challenges such as planning waste collection close to residential areas, and unreasonable land clearance, compensation and dispute settlements. Although the city has selected recycling technology as its key technology, moving towards the complete reuse, recycle, recovery waste treatment model for the whole city; and although the city’s budget is available for MSWM, there is still disapproval from the communities on relocation and compensation that is hindering the transportation of waste into the treatment area. To solve these problems and improve operations, it is necessary for the ministries and central branches to continue to improve the mechanisms and policies around investment preferences, to plan adjusted arrangements and to publicize gathering places to transfer construction waste and waste soil in the locality. The city should strictly deal with cases of dumping waste and discarded soil anywhere other than the prescribed area, particularly dropping soil and waste on the road. The mechanization of garbage collection and transportation is necessary to ensure environmental sanitation. In addition, the municipal authorities need to speed up the approval process, prepare investment projects, and select potential investors to obtain modern and thorough waste treatment technology and a sustainable solution.

5.2.3. Ho Chi Minh City Financial and operational requirements (C9) and facilities and infrastructure requirement (C12) are among the priorities of Ho Chi Minh City. Financial and operational requirements (C9) are supported by central budget, local budgets, foreign donor capital, long-term loans and other capital sources (NGOs, communities’ sponsors). Although financial resources for solid waste management are quite diverse, there is still a serious and unbalanced gap between sectors. The budget allocation is largely devoted to waste collection and transportation, and the cost of waste treatment and disposal is currently very low. The basic investment costs of these facilities cannot be afforded without significant subsidies from the central government, official development assistance or both. The service charges that are collected from users are not even sufficient to cover operation and maintenance costs, much less meet construction or replacement costs. In addition, although it is considered one of the measures to reduce solid waste in solid waste, most composting plants (a popular activity in Vietnam) are facing operational difficulties. Grants from local authorities to operate the composting plants are lower than the allowances for landfills to meet the requirements, and financial measures to support operations are essential. While investment capital for the procurement of equipment and infrastructure for a solid waste management facility is very high, the time for capital recovery is long, especially for enterprises still facing challenges. In general, the fee for solid waste management services only covers a small portion of the total operating and maintenance costs of the management system. These issues suggest that although the budget for waste management has increased over the years, the lack of appropriate legislation and policies (C2) is a threat to the sustainability of investments. The related ministries and branches should coordinate and support financial investment, build preferential economic mechanisms to promote MSWM activities or collaborate to evaluate newly deployed waste treatment technology. The government should encourage all domestic and foreign organizations and individuals to invest and build solid waste treatment facilities and auxiliary works through preferential policies and investment support, such as the free use of money, land and support for site clearance and compensation expenses; a favorable tax exemption policy for importing equipment and raw materials to invest in facilities; and support for the research and development of recycling, reuse and treatment technologies based on domestic resources. Authorities should develop and issue a mechanism to ensure funding for the operating costs of MSWM. Although funding from projects and international cooperation programs is quite generous and diverse, it is not always effective. Some investment projects for solid waste treatment equipment and technology are not modern or suitable for municipal conditions. The

5.2.2. Danang city Resource efficiency (C6) is a specific concern in Danang city. This criterion aims for waste, rather than being discarded, wasted and polluting the environment, to be recovered in the form of different resources and once again utilized in the production and use as a valuable resource bringing economic value to the development of the country. However, the economic efficiency target from waste resources is difficult to achieve. There are no strong secondary markets to buy or sell recycled products. Energy recovery trading markets have not yet been developed; and the authorities have not yet generated sufficient revenue from waste through management policies. To increase the resource efficiency of MSWM, building a circular economy that attempts to promote partnerships in new product design to achieve efficiency and facilitate waste reuse can help reduce the risk of scarcity of future resources, solve environmental problems and generate appropriate revenue to contribute to the municipal budget. Promoting the development of a community awareness strategy, in particular, conducting communication activities around waste separation at the source, and mobilizing community around preventing, refusing, reducing, reusing, recycling, and replacing are suggested. Innovations in MSWM are recommended to advance sustainability by developing products that avoid waste and increase efficiency. Proposals include strictly managing the import of waste as a raw material for production and recycling, resolutely supervising violations, working with the private sector to recycle waste, and encouraging public-private cooperation to improve the standard of living and find the most efficient solutions. This study found that MSWM performance in Danang city is weaker than that in the other two cities. This could be explained by its smaller area, population and density. The MSW collection, transportation and treatment in the city is not well managed, the collection price is low, the state authority is not responsible, and although private contractors collect waste, they discharge it in illegal sites. In addition, construction and demolition waste are collected together with MSW to transport to landfills, and large-sized garbage is not systematically collected, creating ineffective MSWM. Furthermore, policies and municipal communities are not coordinated, the infrastructure has not been completed and education is still limited. The goal of developing services and 11

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facilities and infrastructure (C12) are required urgently. Facilities and infrastructure are still limited, do not meet technical standards and are not guaranteed. The transportation system does not meet the demand for daily MSWM operations, causing waste retention in residential areas resulted in environmental pollution and human health problems. In addition, old machines and equipment are still imported and obsolete technology is transferred due to the lack of specific technical standard document regulations. To replicate this activity, it is necessary to synchronously develop infrastructure such as waste sorting equipment, collection and transit locations, and infrastructure for recycling and reuse. The technological principles and technical features of each cluster of equipment in the processing line, treatment efficiency, solutions for secondary waste treatment, degree of mechanization, automation, transportation convenience and maintenance should be suitable; waste components should be adapted to climate conditions, abrasion resistance, economic and technical conditions and urban scale. The import of used vehicles, machinery, equipment, and technological lines with low use efficiency, a short life cycle, and environmental pollution needs to be forbidden. The municipal authorities should provide a policy including an import tax exception for equipment and materials to invest in solid waste treatment facilities and should prioritize choosing a domestic technology capable of thoroughly handling local MSW with high effectiveness.

MSWM performance and city development. However, there are some limitations to this study. The proposed attributes are collected from the literature, and so the framework might not cover the whole MSWM process. Future studies should extend the framework to a more comprehensive context. Furthermore, even though the validity and reliability of the hierarchical framework are confirmed, the number of respondents should be increased in future studies to ensure consistency and avoid bias. To enrich the literature, investigating another country or providing a comparison between academic findings and practice or between countries and between cities in different countries are encouraged in the future, as this study focuses only on comparisons of cities in Vietnam.

6. Conclusions

Adabre, M.A., Chan, A.P., 2019. Critical success factors (CSFs) for sustainable affordable housing. Build. Environ. 156, 203–214. Alli, B.O., 2008. Fundamental Principles of Occupational Health and Safety, second edition. International Labour Office, Geneva, Switzerland. Amerioun, A., Alidadi, A., Zaboli, R., Sepandi, M., 2018. The data on exploratory factor analysis of factors influencing employees effectiveness for responding to crisis in Iran military hospitals. Data Brief 19, 1522–1529. Arıkan, E., Şimşit-Kalender, Z.T., Vayvay, Ö., 2017. Solid waste disposal methodology selection using multi-criteria decision making methods and an application in Turkey. J. Clean. Prod. 142, 403–412. Asefi, H., Lim, S., 2017. A novel multi-dimensional modeling approach to integrated municipal solid waste management. J. Clean. Prod. 166, 1131–1143. Brunner, P.H., Fellner, J., 2007. Setting priorities for waste management strategies in developing countries. Waste Manage. Res. 25 (3), 234–240. Cervantes, D.E.T., Martínez, A.L., Hernández, M.C., de Cortázar, A.L.G., 2018. Using indicators as a tool to evaluate municipal solid waste management: a critical review. Waste Manage. 80, 51–63. Coban, A., Ertis, I.F., Cavdaroglu, N.A., 2018a. Municipal solid waste management via multi-criteria decision making methods: a case study in Istanbul, Turkey. J. Clean. Prod. 180, 159–167. Coban, A., Ertis, I.F., Cavdaroglu, N.A., 2018b. Municipal solid waste management via multi-criteria decision making methods: a case study in Istanbul, Turkey. J. Clean. Prod. 180, 159–167. Cobbinah, P.B., Addaney, M., Agyeman, K.O., 2017. Locating the role of urbanites in solid waste management in Ghana. Environ. Dev. 24, 9–21. Coffey, M., Coad, A., 2010. Collection of Municipal Solid Waste in Developing Countries. UN-HABITAT, Malta. Deus, R.M., Bezerra, B.S., Battistelle, R.A.G., 2019. Solid waste indicators and their implications for management practice. Int. J. Environ. Sci. Technol. 16 (2), 1129–1144. Dewi, O.C., Koerner, I., Harjoko, T.Y., 2010. A review on decision support models for regional sustainable waste management. November. The International Solid Waste Association World Conference. Diaz-Barriga-Fernandez, A.D., Santibañez-Aguilar, J.E., Radwan, N., Nápoles-Rivera, F., El-Halwagi, M.M., Ponce-Ortega, J.M., 2017. Strategic planning for managing municipal solid wastes with consideration of multiple stakeholders. ACS Sustain. Chem. Eng. 5 (11), 10744–10762. Erkut, E., Karagiannidis, A., Perkoulidis, G., Tjandra, S.A., 2008. A multicriteria facility location model for municipal solid waste management in North Greece. Eur. J. Oper. Res. 187 (3), 1402–1421. Fernando, R.L.S., 2019. Solid waste management of local governments in the Western Province of Sri Lanka: an implementation analysis. Waste Manage. 84, 194–203. Gabus, A., Fontela, E., 1972. World Problems, an Invitation to Further Thought Within the Framework of DEMATEL. Battelle Geneva Research Center, Geneva, Switzerland, pp. 1–8. Gambella, C., Maggioni, F., Vigo, D., 2019. A stochastic programming model for a tactical solid waste management problem. Eur. J. Oper. Res. 273 (2), 684–694. General statistics office of Vietnam, 2019. Area, Population and Population Density by Province. Retrieved June 15, 2019 from. https://www.gso.gov.vn/default_en.aspx? tabid=774. Guerrero, L.A., Maas, G., Hogland, W., 2013. Solid waste management challenges for cities in developing countries. Waste Manage. 33 (1), 220–232. Heidari, R., Yazdanparast, R., Jabbarzadeh, A., 2019. Sustainable design of a municipal solid waste management system considering waste separators: a real-world application. Sustain. Cities Soc., 101457.

Sources of Funding This study is partially funded by MOST 107-2410-H-468-026, Taiwan. Declaration of Competing Interest None. References

MSWM has been recognized as playing an important role not only in environmental protection but also in sustainable municipal development. Nevertheless, in Vietnam, there exist insufficient and inefficient strategies to enable MSWM to approach its goals for public health, ecological improvement and social satisfaction. A set of attributes that consist of 4 aspects, including social acceptability, environmental benefits, economic sufficiency and technical integration, and 14 criteria are with validity and reliability. First, a hierarchical framework for MSWM is developed by adopting EFA. Then, fuzzy DEMATEL is employed to identify the MSWM strategies of cities by considering the causal interrelationships among attributes and technical integration in linguistic references. In addition, because each municipal region has different strategies for developing its MSWM system, a comparison is implemented to present the difference practices of Hanoi, Danang, and Ho Chi Minh City. The findings are technical integration and social acceptability are common to all cities and that control MSWM and economic sufficiency is found to be one of the most common causes for Ho Chi Minh City system, and treatment innovative capacity, safety and health, economic benefit, and technology functionality and appropriateness are confirmed to be the linkage criteria. Moreover, the distinctions between cities are addressed. In addition, Hanoi focuses on the institutional and organizational administration framework, whereas resource efficiency is an aspect of specific concern in Danang, and Ho Chi Minh City prioritized financial and operational requirements and facilities and infrastructure requirements. In the context of MSWM, Danang’s performance is weaker than the other 2 cities. These are the main issues that the practitioner must recognize to achieve higher performance of sustainability. This study contributes to both theoretical and managerial understandings of MSWM by confirming the hierarchical framework and identifying the major attributes that have an essential effect on the sustainable performance of waste management systems. Technical integration and social acceptability are identified as the most important aspects affecting the framework. In addition, treatment innovative capacity, safety and health, economic benefit, technology functionality and appropriateness deserve special concern in Vietnam MSWM. The differences between the compared cities are clear. The guideline action plans are provided for practitioners as a useful reference to provide better decision-making processes and assess sustainability in both 12

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Conserv. Recycl. 51 (2), 418–434. Tan, S.T., Lee, C.T., Hashim, H., Ho, W.S., Lim, J.S., 2014. Optimal process network for municipal solid waste management in Iskandar Malaysia. J. Clean. Prod. 71, 48–58. Tseng, M.L., Bui, T.D., 2017. Identifying eco-innovation in industrial symbiosis under linguistic preferences: a novel hierarchical approach. J. Clean. Prod. 140, 1376–1389. Tseng, M.L., Wu, K.J., Lee, C.H., Lim, M.K., Bui, T.D., Chen, C.C., 2018. Assessing sustainable tourism in Vietnam: a hierarchical structure approach. J. Clean. Prod. 195, 406–417. Tseng, M.L., Wu, K.J., Ma, L., Kuo, T.C., Sai, F., 2017a. A hierarchical framework for assessing corporate sustainability performance using a hybrid fuzzy synthetic method-DEMATEL. Technol. Forecast. Soc. Change. Tseng, M.L., Wu, K.J., Ma, L., Kuo, T.C., Sai, F., 2017b. A hierarchical framework for assessing corporate sustainability performance using a hybrid fuzzy synthetic method-DEMATEL. Technol. Forecast. Soc. Change. Tseng, M., Lim, M., Wong, W.P., 2015. Sustainable supply chain management: a closedloop network hierarchical approach. Ind. Manage. Data Syst. 115 (3), 436–461. United Nations Environment Programme (UNEP), 2009. Developing Integrated Solid Waste Management Plan, Trainning Manual Vol. 3. Targets and Issues of Concern for ISWM, United Nations Environment Programme, Osaka, Japan, pp. 48. Vietnam Center for Environmental Monitoring Portal, 2019. Chuong 2: Chat Thai Ran. Retrieved June 5. 2019 from Jan 5). http://cem.gov.vn/Portals/0/bao%20cao %20moi%20truong/chuong2.pdf?ver=2019-01-05-154220-543. Wang, R.C., Chuu, S.J., 2004. Group decision-making using a fuzzy linguistic approach for evaluating the flexibility in a manufacturing system. Eur. J. Oper. Res. 154 (3), 563–572. Wu, K.J., Liao, C.J., Tseng, M.L., Chou, P.J., 2015. Understanding innovation for sustainable business management capabilities and competencies under uncertainty. Sustainability 7 (10), 13726–13760. Wu, K.J., Liao, C.J., Tseng, M.L., Lim, M.K., Hu, J., Tan, K., 2017. Toward sustainability: using big data to explore the decisive attributes of supply chain risks and uncertainties. J. Clean. Prod. 142, 663–676. Wu, W.W., Lee, Y.T., 2007. Developing global managers’ competencies using the fuzzy DEMATEL method. Expert Syst. Appl. 32 (2), 499–507. Yadav, V., Bhurjee, A.K., Karmakar, S., Dikshit, A.K., 2017. A facility location model for municipal solid waste management system under uncertain environment. Sci. Total Environ. 603, 760–771. Yu, H., Solvang, W.D., 2017. A multi-objective location-allocation optimization for sustainable management of municipal solid waste. Environ. Syst. Decis. 37 (3), 289–308. Yukalang, N., Clarke, B., Ross, K., 2017. Barriers to effective municipal solid waste management in a rapidly urbanizing area in Thailand. Int. J. Environ. Res. Public Health 14 (9), 1013. Zaman, A.U., 2014. Identification of key assessment indicators of the zero waste management systems. Ecol. Indic. 36, 682–693. Zarate, M.A., Slotnick, J., Ramos, M., 2008. Capacity building in rural Guatemala by implementing a solid waste management program. Waste Manage. 28 (12), 2542–2551. Zurbruegg, C., 2003. Solid Waste Management in Developing Countries: A Sourcebook for Policy Makers and Practitioners. EAWAG. SANDEC report. Zurbrügg, C., Gfrerer, M., Ashadi, H., Brenner, W., Küper, D., 2012. Determinants of sustainability in solid waste management–the Gianyar Waste Recovery Project in Indonesia. Waste Manage. 32 (11), 2126–2133.

Henry, R.K., Yongsheng, Z., Jun, D., 2006. Municipal solid waste management challenges in developing countries–Kenyan case study. Waste Manage. 26 (1), 92–100. Ikhlayel, M., 2018. Indicators for establishing and assessing waste management systems in developing countries: a holistic approach to sustainability and business opportunities. Bus. Strategy Dev. 1 (1), 31–42. Kaiser, H.F., 1974. An index of factorial simplicity. Psychometrika 39 (1), 31–36. Kemirtlek, A., 2010. Integrated Solid Waste Management. Istanbul Environmental Management Industry and Trade Co. Ltd., pp. 1–15. Kharat, M.G., Murthy, S., Kamble, S.J., Raut, R.D., Kamble, S.S., Kharat, M.G., 2019. Fuzzy multi-criteria decision analysis for environmentally conscious solid waste treatment and disposal technology selection. Technol. Soc. 57, 20–29. Li, Y.Y., Chen, P.H., Chew, D.A.S., Teo, C.C., Ding, R.G., 2011. Critical project management factors of AEC firms for delivering green building projects in Singapore. J. Constr. Eng. Manage. 137 (12), 1153–1163. Marino, A.L., Chaves, G.D.L.D., dos Santos Junior, J.L., 2018. Do Brazilian municipalities have the technical capacity to implement solid waste management at the local level? J. Clean. Prod. 188, 378–386. Marshall, R.E., Farahbakhsh, K., 2013. Systems approaches to integrated solid waste management in developing countries. Waste Manage. 33 (4), 988–1003. Mirdar Harijani, A., Mansour, S., Karimi, B., 2017. A multi-objective model for sustainable recycling of municipal solid waste. Waste Manage. Res. 35 (4), 387–399. Mohammadi, M., Jämsä-Jounela, S.L., Harjunkoski, I., 2019. Optimal planning of municipal solid waste management systems in an integrated supply chain network. Comput. Chem. Eng. 123, 155–169. Morrissey, A.J., Browne, J., 2004. Waste management models and their application to sustainable waste management. Waste Manage. 24 (3), 297–308. Ngoc, U.N., Schnitzer, H., 2009. Sustainable solutions for solid waste management in Southeast Asian countries. Waste Manage. 29 (6), 1982–1995. Opricovic, S., Tzeng, G.H., 2004. Compromise solution by MCDM methods: a comparative analysis of VIKOR and TOPSIS. Eur. J. Oper. Res. 156 (2), 445–455. Pires, A., Martinho, G., Chang, N.B., 2011. Solid waste management in European countries: a review of systems analysis techniques. J. Environ. Manage. 92 (4), 1033–1050. Robins, L., 2008. Making capacity building meaningful: a framework for strategic action. Environ. Manage. 42 (5), 833–846. Seng, B., Kaneko, H., Hirayama, K., Katayama-Hirayama, K., 2011. Municipal solid waste management in Phnom Penh, capital city of Cambodia. Waste Manage. Res. 29 (5), 491–500. Shekdar, A.V., 2009. Sustainable solid waste management: an integrated approach for Asian countries. Waste Manage. 29 (4), 1438–1448. Singh, A., Basak, P., 2018. Economic and environmental evaluation of municipal solid waste management system using industrial ecology approach: evidence from India. J. Clean. Prod. 195, 10–20. Sisto, R., Sica, E., Lombardi, M., Prosperi, M., 2017. Organic fraction of municipal solid waste valorisation in southern Italy: the stakeholders’ contribution to a long-term strategy definition. J. Clean. Prod. 168, 302–310. Soltani, A., Hewage, K., Reza, B., Sadiq, R., 2015. Multiple stakeholders in multi-criteria decision-making in the context of municipal solid waste management: a review. Waste Manage. 35, 318–328. Su, J.P., Chiueh, P.T., Hung, M.L., Ma, H.W., 2007. Analyzing policy impact potential for municipal solid waste management decision-making: a case study of Taiwan. Resour.

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