**1. Introduction**

Sustainability and sustainable development as concepts have gone through different development stages since their introduction. The historical development of the concept has been carried out at various conferences and within organizations and institutions, which are currently concerned with the implementation of the principles, targets, and objectives of sustainable development [1]. The concept of sustainable development has encounter over time different criticisms and interpretations, being accepted in different fields of activity. The concept of sustainable development, throughout its evolution, has adapted to environmental and technological requirements, but the heart, principles, directions, and objectives have been preserved and are still present. Due to the fact that the environment is dynamic and new aspects come in, some sustainable development goals have been updated. The objectives of sustainable development are contained in the 2030 Agenda. At the same time, the objectives of this agenda contribute to the survival on the planet and to the increase of the standard of living [1,2].

If sustainable development initially focused more on the environmental dimension, gradually, obligations regarding the social and economic dimension have been added. The concept of sustainable

development has become one appreciated by organizations due to the identification of organizational benefits and advantages [2–5].

The social and economic aspects are addressed and appreciated by the organizations involved in sustainable development [6]. Five decades ago, society was characterized by consumerism, economic growth, polluted living space, and unorganized ways of living [2–7]. The exploitation of some natural resources contributes to the entrenchment of the right to a decent living for the next generations. The needs of the population are inversely proportional to those of the organizations.

Imbalances in the environment contribute to the generation of negative effects for future generations. Pollution is a major environmental problem. Among the sources of pollution are: (1) the development of the economic environment (economic growth, traffic intensification, traffic improvement, increasing the number of inhabitants, increased tourism, etc.), (2) natural hazards (earthquakes, severe rain, volcanic eruptions, droughts, wind, etc.), and (3) technology (different networks built, new concepts, intensification of the use of information technology, construction of different attractive products for users, waste management, etc.) [8–11]. These factors contribute to the occurrence of consequences, some severe, which concern ecological problems, ecosystem instability, global climate change, natural disasters, hunger and poverty, lower quality of life, etc. [10].

The global scenario of depletion of natural resources and environmental, economic, and social imbalance motivates organizations and individuals to adopt sustainability practices in organizational processes. Sustainability was born many years ago, but few guidelines are available for its practical implementation and evaluation [8–11]. The research [3] states a considerable impact of sustainability on the environment. This research presents the impact of greenhouse gases and waste on the environment. Reference is made to the wood industry, energy, and heat generation. The researches [4,5] states that sustainability is achieved in the field of transport and adjacent industries and emphasizes the reduction of environmental impact. Previous research [6] presents sustainability studies in the airline field, and the automotive industry must be evaluated and analyzed in future research. Other research [7] presents the impact of sustainability in the fashion industry. Further research [8] presents the impact of sustainable development in the foam and chemical industry, presenting different visions. It is specified that the automotive industry has a considerable impact in the field of sustainability, without specifying these impacts. The research by Amui et al. [9] has various implications for the food industry. From the analysis of the different definitions discussed in several studies [3–9], it was observed that the approach on sustainability in manufacturing is not yet concretely developed. Sustainable development improves the conditions of companies, thus contributing to their competitiveness. Sustainable development is a voluntary approach, but it is increasingly adopted by companies. Stakeholders are interested in this concept as long as they get improved financial results (increased profit). The first direction was the one of environmental sustainability, with major implications for national and international authorities and organizations [5]. However, sustainability is now defined by three dimensions—environmental, social, and economic [10]. Pervious research [5,6] addressed sustainability in land and air transport industries. It emphasizes the importance of addressing sustainability in this industry as a result of generating a large amount of greenhouse gases. The results published in reference [7] highlight the impact of sustainability in the fashion industry and the impact it has social impact by producing the articles used by the final customer who is in the society. The importance of occupational safety and health in this industry is also mentioned. This industry focuses on re-manufacturing, reconditioning of items, use for other purposes, reuse of other people's items, recycling materials by implementing buy-back (in various stores), reducing the impact on the environment by using natural materials (bio-cotton, wool, etc.), repair and recovery of items to meet basic needs, redesign of the manufacturing process by including automatic lines, and reconditioning items to be used until the end of their life cycle. Other research [8] presents studies in the foam and chemical industry and emphasizes the importance of renewable energy sources. In the same direction as the fashion industry, the food industry is one that addresses the end customer, and the functions of sustainability are addressed. One study [9] concerning the food industry refers to the 9Rs (remanufacturing, reconditioning, reuse, recycling, reduce, repair,

recover, redesign, and reconditioning). The importance of the 9Rs in the entire manufacturing process is underlined.

Another study [10] specifies the imperatives of Industry 4.0 and its importance in the current economic development. Therefore, five important reasons can be systematized. Sustainable manufacturing is one of the most important issues to address for the following five important reasons [5–10]:


Organizations implement various strategies, in accordance with the interests of their stakeholders and good practices to make their processes environmentally efficient and sufficiently socially and economically viable. Therefore, it is suggested that manufacturing integrate production processes that pursue sustainable manufacturing practices. It is imperative that a study should include all aspects of sustainability related to stakeholder involvement, the entire logistics chain, and strategies up to the end of product life [6].

The practices, methods, and tools used for sustainability assessment in the manufacturing industry are based on a pioneering roadmap for applying the imperatives of the circular economy in the context of Industry 4.0. The results of this research refer to the presentation of the relationship between circular economy and Industry 4.0, as well as the improvement of the ReSOLVE (Regenerate, Share, Optimise, Loop, Virtualise, Exchange—a framework with six action areas for businesses) framework [11]. It is an approach based on specialized literature and qualitative evaluation. Another model [12] aims to integrate technologies from Industry 4.0 integrated with circular economy (EC) practices to provide a business model. This business model is based on the reuse and recycling of ferrous materials and waste. It is based on qualitative evaluation. A study of 600 German companies claims that the opportunities of digital networks are used to a limited extent, especially for streamlining production processes [13]. This study does not present an improvement framework, but only an evaluation of the results obtained from the market research. Other research offers a synergistic and integrative circular economy-digital technologies framework based on the empirical literature [14]. The research results state that the research directions of the circular economy have been submitted, but the research and applicability of the digital technologies that allow an EC are still in the basic form. Another study presents "X" production systems (XPS) and the importance of lean manufacturing and continuous improvement principles [15]. It presents the situation of a company that has better aligned its XPS with the sustainability objectives. Following that research, the indicator panel and the evaluation framework are completed. Other research [16] takes into account the life cycle of the product, stakeholders, employees and customers, and end-of-life strategies, but also includes environmental, social, and economic aspects in a single comprehensive review on the aforementioned directions. The results highlight an integrated approach based on various research in this direction.

In summary, other research is based on sustainable value stream mapping [17], use of multi-criteria decision making [18], assessment questionnaires [17–19], indicator-based assessment [19–21], rating system [20], scoring tools [21], software tools [20], mathematical modeling [20–23] life cycle analysis [24–26], product service systems [27], and a sustainability index [27,28]. By evaluating these approaches, it can be seen that the research covers the evaluation of the sustainability via the measurement of performance taking into account certain practices and indicators. Therefore, an integrated framework for sustainability assessment, including product life cycle engineering, stakeholder interests, supplier and supply chain management, employees and customers, and end-of-life strategies is impetuous to develop. These approaches [17–28] are applied on specific business typologies without taking into account the opportunities and requirements of Industry 4.0. The framework that this research seeks to develop takes into account the behavior of different companies in the manufacturing industry and the characteristics of the Industry 4.0. Previous studies do not take into account the characteristics of Romanian manufacturing industry. This research does not use as a research method, discussions on the results obtained with experts in the field.

This paper is structured in two main directions: researching the characteristics of Industry 4.0 and of the indicators that evaluate the organizational sustainability. Finally, the hierarchical framework for sustainability assessment of manufacturing industry is pre-tested and validated. This research presents a new evaluation framework, which integrates the goals of sustainable development and those of Industry 4.0. To develop this framework, market research was conducted to identify the current needs and implications in Industry 4.0. This research was validated following discussions with manufacturers in the manufacturing industry. These debates were based on the Delphi method. Finally, a hierarchical framework was developed based on the needs identified and validated through the Delphi method. This framework is used to evaluate and improve the involvement of companies in the manufacturing in sustainable development and reduce the negative impact on the environment.

#### **2. Research Methodology**

The research methodology comprises three research directions—market research by means of a questionnaire applied to 100 manufacturing industry experts, the Delphi method involving one facilitator and 40 experts, and the author's empirical experience. All the phases of the research are progressively completed, and finally, the proposed framework is pre-tested and validated.

#### *2.1. The Questionnaire*

Marketing research helps to identify the needs and desires of the clients [29]. There are a number of tools, but a questionnaire survey is a facile, cheap, and easy to apply method. The questionnaire provides an easy to apply way to contact a number of individuals [29–35]. Various questions may be asked depending on the type of information that is to be obtained. A questionnaire can feature open-ended questions (completely unstructured, structured, describing an image), closed questions with predetermined answers (with different scales—Stapel, semantic differential, constant amount appreciation attribute), or mixed questions. If the goal is to collect motivations and opinions regarding the creativity and innovation of the respondent, then open questions will be used. If all the answer variants can be anticipated, then closed questions will be used. In other situations, mixed questions can be used [31].

In this research, the questionnaire was used to identify the characteristics and imperatives of Industry 4.0 in Romania. This research tool has been applied to shareholders throughout Romania. The informants were 100 shareholders, directors, or managers. The confidence level is 95%, and *p*-value > α. These results emphasize that the null hypothesis is not rejected. The 100 companies were selected from the classification of companies based on turnover, net profit, and number of employees (top 100 companies). This classification was made on the basis of data from the Trade Register and National Institute of Statistics. The application of the questionnaire was done online and was specific to each previously identified respondent. The respondents were identified according to the activity field of the company. It was intended to cover all areas of activity in the manufacturing industry. All responses were valid. The Likert scale (1—least important and 5—most important), distribution of a set score (0—poorly implemented and 100—fully implemented), and open questions were used. The questionnaire was structured in four parts, Table 1: information about the company; Industry 4.0 interpretation, facilitators, and barriers; and Industry 4.0 maturity and national technology platform. The results obtained in this research are used to develop the hierarchical framework for sustainability assessment in the manufacturing industry.


**Table 1.** Sustainable development and Industry 4.0.

#### *2.2. Delphi Method*

The Delphi method is a forecast framework that includes the results of several rounds of questionnaires sent to a group of experts [15]. The results of a round are recorded, and then they are sent to the expert group, and the anonymous responses are aggregated and shared again to the expert group [15–18]. The process of applying this method is shown in the figure below. The Delphi technique is a method used to estimate the probability and outcome of future events [15]. The expert group exchanges opinions, and each expert personally provides estimates and assumptions based on their experience to a facilitator, who examines the data and develops a summary report [19–21]. Experts review the form of the report, and a new (second) report is issued. This process continues until all experts/participants agree with the developed report. This technique is an iterative one and is successfully applied in management and in different approaches to competitiveness [18]. In this area, sustainable development also has its place [32–35]. The Delphi method clarifies and extends problems to identify all areas and features that need modification [36]. In the present research, we used the Delphi method to identify all sustainable performance measures for improving organizational policies, people, processes and products. The following steps are presented in Figure 1. For the application of this method, a facilitator was identified from the automotive industry, being the manager of the processes and research-development department. The facilitator is characterized by over 30 years of experience in manufacturing, is the manager of a company with over 3000 employees, has personal involvement in sustainable development, is a good communicator, and has the capacity to analyze (as a result of the competences registered on the basis of certificates obtained at the international level).

The automotive industry has a significant percentage of manufacturing in Romania (it generates over 15% of gross domestic product [37–40]). Industries have their peculiarities and must be evaluated in a complex way [40–44]. The construction of the sample of respondents from different fields contributes to the achievement of an integrated framework for evaluating sustainable development [45–47]. Forty experts participated in the analysis rounds. Individuals with solid expertise and sustainability skills were selected. The database used for the selection of experts was the one from the application of the questionnaire (of the 100 respondents). There were six segments in the manufacturing industry identified based on the activity performed [38] in Romania. These segments, their percentages, and the targeted directions are presented in Table 2.

**Figure 1.** The stages of the Delphi method used in establishing the hierarchical framework for sustainability assessment of manufacturing industry.


**Table 2.** Sustainable development and Industry 4.0.

### *2.3. Empirical Experience*

The interest in sustainable development over the last 10 years and the multiple studies carried out on the subject (over 150 works) have contributed to the extension of the research toward this model of manufacturing. The research carried out [48–53] has contributed to the foundation of the concept and to the identification of measures and performance indicators. They are the pillars of the hierarchical framework for sustainability assessment. The author has contributed as the main author to the development of a series of studies that have advanced the field of sustainability (Table 3).


**Table 3.** Research by the author in the field of sustainability and innovation.

#### **3. National and International Situation in the Manufacturing Industry**

Manufacturing is the production of goods intended for use or sale with labor and machinery, instruments, processing, or chemical or biological formulation [36]. Finished products can be sold, through a distribution chain, to other producers for the production of more complex products or redistributed through the tertiary industry to final consumers [15–20]. In order to characterize manufacturing, a qualitative evaluation of the existing data series in the databases of the accredited institutes is performed. To characterize manufacturing, the following characteristics are taken into account: the number of employees, the amount of waste generated, the greenhouse gas emissions, and the level of innovation. These indicators are presented for the European Union (EU) and Romania [38–41,44,45].

The number of employed persons in the European Union decreased to 230,356,800 in the first quarter of 2019 from 231,342,700 in the fourth quarter of 2018. Of the EU employees over 15% are in the manufacturing industry.

In Romania, the number of employees in industry, construction, trade and other services in 2018 was 8,197,014, and in 2019, 8,249,779 employees. The employee is the person who exercises his activity on the basis of an employment contract in an economic or social unit—regardless of its form of ownership—or to private persons in exchange for a remuneration in the form of a salary, paid in money or nature, under commission form and others [38,39,54]. Figure 2 shows the main areas of activity and the number of employees for the period 2017–2019.

From the perspective of the quantity of waste generated, at the EU level, there were 2,116,310,000 tons in 2016 and 2,125,300,000 in 2017. From the perspective of the countries that generate these quantities, the situation is presented in Figure 3. The series is presented according to the reported data (some countries have not reported the amount of waste generated). Romania generated 176,742,421 tons of waste in 2017.

**Figure 3.** Amount of waste generated in the European Union (EU) for 2016–2017 (tons) [45].

Of the total amount of waste, at the EU level, 253,440,000 tons in 2016 and 258,890,000 tons in 2017 were generated by the manufacturing industry (Figure 3). The percentage of waste generated in manufacturing is over 10% of the total waste generated. For Romania, the quantity of waste generated by manufacturing was 6,727,021 tons in 2016 and 7,770,090 tons in 2017 (Figure 4.)

**Figure 4.** The quantity of waste generated by the manufacturing industry in EU countries for the period 2016–2017 (tons) [45].

From the perspective of the quantity of greenhouse gases emitted, the EU generated 4,461,685.11 tons in 2016 and 4,492,127.01 in 2017. Of this quantity, over 10% was generated by the manufacturing industry. Romania generated 115,150.66 tons in 2016 and 114,811.43 tons in 2017. The manufacturing industry in Romania generated 12,836.27 tons in 2016 and 13,105.39 tons in 2017. It can be seen that over 10% is generated by the manufacturing industry in Romania as well. The EU trend is also followed nationally.

Thus, it can be stated that the manufacturing industry is an important economic activity, with considerable contribution in EU and Romania, and this research approach is essential in this field.

#### **4. Characteristics of Industry 4.0**

Manufacturing processes are responsible for a significant portion of the consumption of natural resources and the generation of greenhouse gases. Manufacturing is defined as "the transformation of materials and information into tangible and intangible goods to satisfy the needs and desires of the buyers" [21,55–57]. The industry sector, including production, consumes almost half of the total energy delivered worldwide [15]. In the US, manufacturing absorbs more than 42% of total energy consumption [18,58]. Similarly, in China, the manufacturing sector absorbs 58% of total energy consumption [59,60]. As a result, numerous efforts have been made to reduce the environmental impact of different manufacturing processes, and several strategies have been implemented to monitor, improve, and control variables such as energy consumption [14–19], carbon emissions [15–18], the development of sustainable jobs [18–20,61], and the integration of innovative solutions [20–22,62].

Within this framework of sustainable development, Industry 4.0 appears as an industrial opportunity. The concept of Industry 4.0 began as a strategic framework for industrial production conceived and implemented by the German government in 2011 [10–24]. Industry 4.0 can be defined as a combination of technologies and value concepts applicable to organizational processes [16–18]. This is a general transformation using digital integration and intelligent engineering [26–28,61]. Industry 4.0 imperatives are in the following directions: the preparation of an intelligent, computerized, optimized manufacturing environment, which guarantees the flexibility and high efficiency of production and minimal impact on the environment [21–27,62]. Therefore, approaching Industry 4.0 in the context of sustainable development [63] is mandatory because the potential results obtained from this approach are productivity and resource efficiency [64]. For example, in previous studies [25–29], it is emphasized that Industry 4.0 encourages digitization by offering new efficient approaches to process control using the Internet of Things and integrating cyber-physical systems into manufacturing, which can improve resource and energy efficiency, and automated manufacturing concepts will increase the level of innovation and will reduce the amount of waste generated [30]. Industry 4.0 describes the progressive fusion of industrial production processes with the digital world of information technology.

Evaluating the two approaches—sustainable development and Industry 4.0 framework in the manufacturing industry—we can identify the following applications in manufacturing [22–36]. This analysis takes into account the 17 objectives and 169 goals of sustainable development (17 sustainable development goals—SDGs and 169 goals) and the definition of Industry 4.0. The entire analysis is based on studies published in the literature and are based on the needs of the manufacturing industry (see Table 4). For example, simulating different algorithms contributes to reducing poverty by proposing frameworks for improvement and identifying problems, improving living conditions, education through access to technology, identifying gaps for energy efficiency and improving conditions and outcomes for social responsibility.


