The importance of lean production in the optimization of operational processes is underscored by Reis and Figueiredo (1995, p. 40) when they warn that "waste from overproduction refers to the manufacture of lots in a quantity exceeding immediate market demand, forming not only stocks, but also concealing losses with defective units, delays and errors". Elias and Magalhães (2003, p 2) also contribute when defining:

Waste means any activity, which absorbs resources but creates no value. Value means the ability to offer a product/service at the right time at an appropriate price, as defined by the customer. The basis of lean production is once waste was disposed, it reduces production costs and maximizes customer satisfaction, in other words, the added value.

The goal of reducing waste visualized by lean production should be aligned with the objectives developed by the practices of environmental management, since this reduction contributes significantly to minimize the environmental impacts of industrial operations.

For Ritzman, Krajewski and Malhotra (2009, p. 288):

The Just-in-time (JIT) philosophy is simple but effective - eliminates waste by reducing excess capacity or inventory and removing activities that do not add value. The goals are to create products and services when needed and continually increase the benefits of the added value of operations.

Thus, the JIT is not characterized only as a technical operations management, or as a work philosophy, that integrates concepts and practices of material management, quality management, process management, delimitation of physical arrangement, the management of the supply chain and human resources. Before, it has as main objectives the quality and flexibility by applying continuous improvement practices and relentless pursuit of reducing waste in the production process (CORRÊA & CORRÊA, 2005).

In the view of Ballestero-Alvarez (2010, p. 255) "the ultimate goal of JIT is to provide fast answers to customers while minimizing inventories." Authors such as Slack et al. (2010, p. 355) conceptualize JIT as a way to "produce goods and services just when they are needed - neither before so they do not become stock, nor after so customers do not have to wait." So, it aims to meet the demand instantaneously, without compromising the quality and further reduce waste the most, by reducing the size of lots of shopping, and acting in a continuous evolution of processes and learning of employees (LIKER & MEIER, 2007).

According Abreu, Alves and Moreira (2017, p. 4) the Lean-Green management, includes “lean indicators, green performance indicators and green intentions indicators, for a benchmarking repository”. The authors use it to benchmarking for lean and green practices of a consortium of companies in order to target a improve operation results.

In this way, the adoption of lean manufacturing practices to reduce waste and maximize the resources used in production could be consider as the starting point for raising efficiency and minimizing the environmental impacts caused by industrial production (SALVADOR, PIEKARSKI & FRANCISCO, 2017).

Companies seek profit and profitability as a top reason for its existence and finds in meeting the needs of customers, the main way to achieve this profit. In the current business world, society exacts the organizations a policy of environmental management in order to enhance the use of environmentally friendly products, in other words, products and services designed to cause the least possible impact on the environment.

According to Barry and Rondinelli (1998, p 38), the world entered a new Industrial Revolution and, due to the pressure from the market, organizations need to act proactively on the management of the environment and natural resources. "Environmental sustainability is a new value that should be adopted by multinationals so that they can become more competitive and successful."

In enterprise management, the term sustainability is constantly refer to as the perpetuation of conditions favorable to the organization. Furthermore, this concept is incorporate, through systemic view, into the social and ecological dimensions, so that they form a broader knowledge about the economic goals of these companies and the need of customers.

In Barbieri’s concept (2007, p. 25), environmental management is formed in "guidelines and administrative and operational activities, such as, planning, direction, control, resource allocation, and others performed with the aim to achieve positive effects by human actions, or preventing them from arising."

For Yang, Hong and Modi (2011, p. 252) “Environmental management practices refer to programs to improve environmental performance of process and products in the form of eco-design, recycling, waste management and life-cycle analysis”.

This new "environmental conscience" of society has driven the search for organizations by methods and techniques of production operations that preserve the natural and/or reduce the impact generated by its production process, in order to improve its competitive advantage and image related to its products and services (Almeida, 2009; Nascimento, Lemos and Mello, 2008).

From the same perspective, Sanches (2000, p. 77) highlights that "industrial companies seeking to maintain competitive increasingly realize that, given the environmental issues, new positions are required, in a continuous renewal process." In this sense, environmental management can interpreted as the science that seeks to identify, assess and control the reduction of environmental impacts and develop strategies for the conservation of natural resources. Similarly, the concept of Green Supply Chain seeks to ensure the minimization of environmental impacts in the supply chain acting directly on the suppliers that adopt good environmental practices as assert Nascimento, Lemos and Mello (2008).

According Srivastava (2007, p. 54), Green Supply Chain Management (GSCM) is a “integrating environmental thinking into supply chain management, including product design, material sourcing and selection, manufacturing processes, delivery of the final product to the consumer as well as end-of-life management of the product after its useful life”.

The pursuit of improvement in environmental performance in organizations, done by reducing waste and air emissions, or a better mix of inputs, will represent a gain of energy or materials within the production process. So that these companies can transform the expenses coming from this reduction process in positive financial results, either by reducing costs of production or reusing waste and increasing recycling possibilities of these materials (Donaire, 1995).

For King and Lenox (2001, p. 246):

“Environmental management systems (EMS) share many characteristics with lean production. Most EMSS emphasize formal monitoring and improvement of facility waste streams. Like lean production systems they often include opportunities for collaborative problem solving and continuous improvement”.

The environmental management strategies that have their goals aligned to those developed by lean production, and seek the joint use of methods and techniques of different prominent environmental strategies, can help to raise the level of effectiveness of lean production. This is achieved through systemic view that organizations have, thus, contributing to reduce waste and increase productivity.

Similarly, authors such as Simons and Mason (2003) argue that the reduction of waste and emissions can be cause by the use of lean production in the production process of industrial organizations. Therefore, it can assumed that modern organizations are able to use tools of lean manufacturing to enhance the development of environmental management in their production processes (LEWIS, 2000).

Organizational systems are composed of subsystems of internal processes that are interrelated. Thus, the different areas of the company perform specific activities, but all are acting together in pursuit of achieving the strategic goals set by senior management. This systemic relationship is essential to the achievement of results and the control of the operation of organizational processes, since the entire organization must be engaged in meeting the expectations of stakeholders and achieving better economic development.

Dhingra, Kress and Upreti (2014, p. 2) agree:

“Manufacturers that are already on the lean production path are beginning to realize that lean to green is a natural progression, and that monetary savings can be realized not just by the implementation of lean practices but by implementing cleaner production methods as well.”

The systemic approach allows the examination of a number of interrelationships, by crossing the boundaries of functional departments, and can be faithfully represent by the concept of environment.

For Yang, Hong and Modi (2011, p. 253):

“Lean manufacturing creates, within an organization, the orientation to increase employee responsibility and involve employees in waste reduction effort. Such lean orientation may also help firms to adopt environmental management practices which aim at reducing wastes and pollutants reduction”.

Simpson, Power and Samson (2007) agree suppliers of a supply chain if the show more engaged when their clients have a higher requirement on environmental indicators, thus raising the level of relationship and improving environmental performance. They also suggest that the conditions in the relationship with these suppliers run of environmental performance requirements (investments, contracts and monitoring routine) adopted by customers, encouraging environmental commitment and responsibility.

The systemic approach of the companies can still make use of different production strategies to achieve better operating results when associating the best practices of different strategic models in key areas of the organization. Thus, the combined use of techniques of lean production and environmental management can contribute in a systematic way to achieve better business results and enhance the care of customer needs (Johanson and Sundin, 2014; Yang, Hong and Modi, 2011; Rothenberg, Pil and Mawell, 2001).

According to Abreu, Alves and Moreira (2017, p. 1):

“Lean is a strategy that encompasses a wide variety of management practices, in an integrated system, to streamline business processes, minimize waste and improve financial performance. When lean and green are associated in the called Lean-Green link, many of those savings also result in environmental benefits.

Elias and Magalhães (2003) emphasize that the tools developed by lean production contribute to the achievement of environmental, technological and economic benefits, as they minimize the need for resources, energy and raw materials.

Saurin, Ribeiro and Marodin (2010) also reinforce that the emphasis of lean production in waste reduction helps to reduce the environmental impact of production systems providing opportunities for the integration of lean efforts and environmental management.

In this scenario, we seek to identify the Lean Manufacturing (Lean) as an example of competitive advantage, reducing waste in the production process and Environmental Management (Green) as a competitive strategy for reducing the environmental impact caused by production operations in organizations. Thus, environmental management has a strong interaction with the objectives of operations in organizations as "efforts to reduce pollution and efforts to maximize profits share the same basic principles, including the efficient use of inputs, materials substitution and minimization activities unnecessary" (Porter and Linde, 1995, p 122).

The studies of Saurin, Ribeiro and Marodin (2010) therefore argue that adopting lean practices influences environmental proactivity on business, or the more widespread lean production in these organizations, the less waste and costs at the end of the process productive. Therefore, the implementation of a policy of lean production in organizations, aiming at the reduction of waste, tends to influence in any way the development of environmental management practices by promoting growth of this area of performance in organizations.

Bergmiller and McWright (2009) suggest that in turn modern industrial organizations are adopting the goals of lean and green in their business models in a more incisive and yet transcending the Cleaner Production (CP) as a natural evolution culture of waste reduction continuously integrating its programs to minimize the environmental impacts of its productive operations.

King and Lenox (2001) propose that lean production is complementary to environmental performance and the adopt practices of lean on companies contribute to minimize pollution and waste. While Yang, Hong and Modi (2011) agree that as an organizations uses lean manufacturing practices to reduce wastes and could reduce the environmental impact.

Rothenberg, Pil and Maxwell (2001) agree that lean manufacturing contributes to improving environmental performance, but other features as are necessary: the participation of stakeholders includes top management support and engagement of suppliers in order to have greater efficiency these results.

The three researched companies and respondents of the research showed the following characteristics:

After the compilation of data obtained, it was proceeded the triangulation of sources of evidence, starting for the individual characterization of each of the researched companies. For a better visualization of the results is present a joint analysis of the cases, as illustrated in Table 1, to enable the features, observed by the collected information in the research instruments, to be exposed in a comparative manner, facilitating the analysis together.

Table 1
“Cross-Case” Analysis / The autors (2012)

In the profile of the researched companies was identified that the three are large, based on the classification of Brazilian Institute of Geography and Statistics - IBGE (2012), according to which are well regarded companies that have from 500 employees in its staff. Regarding the scope of their operations, two (Power and Steel) work both in the national and international territories and the other (Industry) is only national.

The diversification of economic sectors where the companies operate was also an evidenced characteristic by the diversity of the respondent’s profile who are mostly male, young (about 27 years old) and working in the company for at least six years. These professionals play the roles of managers, engineers, analysts and assistants and mostly have college degrees (50%), with 25% of those taking postgraduate courses and 25% having incomplete higher education.

As for the standard-setting instruments that guide the actions of the researched companies, it can be noticed in Table 1 that even acting in different economic sectors, the three companies seek to develop a well-structured system of quality because, besides ISO 14001, they also have other quality certifications (ISO 14064, ISO 9001, ISO 9002), suggesting thereby that compliance with the minimum requirements of these sectors in the use of these policies are adopted. This fact can be confirmed by the executive advisor of "Steel":

There is a sector of EMS (Environmental Management System) in each unit of the group that gives support to all areas of the process and in this sector these principles are considered. Every employee was trained in EMS to meet possible demands.

In Lean-Green perspective, the workforce's commitment to processes and the policy of waste reduction is one of the pillars for improving efficiency. This benefit must be respect for all organization to improve result of lean-green performance (ABREU; ALVES; MOREIRA, 2017).

According to the logistics assessor of "Steel", the main objective of its environmental management system is to "ensure all the monitoring process, from the use of raw materials, through manufacturing and distribution of products to the correct destination of products that were created in the process". Reinforcing the arguments of the respondent, the environmental policy of the company values ​​mainly for the protection and preservation of the health and safety of its employees, the environment and quality of products and services (Steel web site, 2012).

In the search to use the differentiation strategy, effective control of productive activities is essential as an indispensable condition for any company to compete on equal terms with its competitors in today's business world. Without this control and without the ability to evaluate the performance of its activities and intervene quickly to correct failures and improve processes, the company will be at a disadvantage in the face of more efficient competition.

Similarly, the annual sustainability report (2010) of the company "Electric Power" identified strategic direction with regard to three main factors: environmental (regarding environmental preservation and responsible consumption), social (standard of living, personal and professional development) and economic development (the commitment to value creation and profitability, based on sustainable growth), as well as the high level of annual investment in social projects and environmental management.

This environmental concern is evidenced by the search company "Electric Power" in raising environmental awareness in its employees and partners, as outlined in its annual sustainability report (2010, p.172).

In the "Industry" environmental policy, the major focus is on the prevention of pollution, reduction of environmental impacts of the manufacturing process, the search for the well-being of the community of employees, the optimization of natural resources and compliance with laws and other requirements apply to its environmental aspects ("Industry" website, 2012).

Another feature that needs to be taken into consideration for comparative analysis is that the three companies already use Lean Production System (SPE) for over five years and agree that the process is the area that is identified more in reducing waste, followed by logistics and supplies, and then by quality management.

These characteristics are in line with the arguments of Gonzáles-Benito and Gonzáles-Benito (2006), who point out that organizations have increasingly applied techniques to minimize the environmental impacts caused by their productive activity as a way to meet customer requirements, which have intensified the search for products that do not degrade the environment, as well as due to regulation which has also been developed in order to increase the control and taxation of companies, in order to raise the level of government control over these operations.

As shown in Table 1, reducing costs and waste is the main reason for the implementation of the Lean Production System by companies "Electric Power" and "Steel", which also make use of performance indicators and mapping of processes to perform benchmarking these systems. On the other hand, even identifying customer demand as the main motivation for the adoption of the SPE, the company "Industry’’ uses the tools of this system (Kanban and Pokayoke) in order to improve the operation of their activities.

Besides that, the company "Electric Power" uses performance indicators to measure the reduction of air emissions through a monitoring sample, as shown by its annual sustainability report (2010, p 172.): "In its environmental monitoring plan, the company sets the systematic control and performance indicators in order to ensure compliance with the conditions of licensing and legal requirements".

Meeting the pressures imposed by environmental legislation and customer requirements and the need to improve the image of the company are the motivating factors that led the three firms to adopt EMS, being characterized that all the companies adopt environmental criteria for the selection of their suppliers, which shows an alignment to the principles of Green Supply Chain Management as a way to ensure the minimization of environmental impacts in the supply chain. These findings correspond to the arguments put forward by Nascimento, Lemos & Mello (2008) on sustainable supply chain.

Concerning the relationship with suppliers, the company "Electric Power" wants to select this segment prioritizing those that are aligned to its social and environmental objectives, still concentrating its purchases of materials in local suppliers, thus having possibility to develop and monitor way more effective these partners, and thus obtain a differentiation of price and quality in their products. As described in its annual sustainability report (2010, p 110.): "The company seeks to extend the positive impact intended for their domestic audience, as care involving ergonomics, training, education, and healthy work environment for all its business chain".

In the company "Industry", the quality objectives and the development of new processes to seek continuous improvement, innovation and development of new technologies, such as machinery and management systems. And the use of various inspection points in the supply chain (storage, furnaces, molding, blasting, machining and shipping), as a way to reduce the rate of process failures , the incidence of defective parts and waste materials with the incidence of rework ("Industry" web site, 2012).

Still in "Industry", it was found that its quality policy is the provision of security products and services are responsible to ensure customer satisfaction and integrity of the user at the lowest possible price, in the development of its employees through an ongoing process of awareness, recovery and training, and improving the integrated management system through continuous improvement (‘’Industry’’ website, 2012).

Environmental management strategies that have their objectives aligned with those develop by lean production and seek the joint use of methods and techniques of different environmental strategies can contribute to raise the level of effectiveness of lean production. This is done through the systemic vision that the organizations have, thus contributing to the reduction of waste and the increase of productivity (COELHO et al., 2008).

Regarding the contribution of Lean Production practices to reduce environmental impacts caused by the production process, the majority of the researched respondents in the three companies (about 75%) identified a positive contribution of these practices. It was also considered that the principles of environmental management are applied to the activities of the Lean Production System (about 60%). According to the analyst of the company "Electric Power": "with the implementation of Lean Production technologies, it automatically reduces all indicators of environmental impacts and the environmental management becomes cheaper and more efficient".

Reverse logistics is recognized by all companies as a tool of lean production that contributes significantly to the reduction of environmental impacts and reducing operating costs. These findings suggest that reverse logistics also contributes to Lean and Green, as a part of the reduction of industrial waste is being held in these companies through the reuse of surplus production (scrap). In the companies "Industry" and "Steel", this activity is directly linked to the production process and operation of supply of materials from suppliers, while in the company "Electric Power", reverse logistics is applied to the maintenance of equipment in production, in power distribution to customers and in the promotion of environmental projects for recycling and reuse of materials in the community.

Reverse logistics is still treated as a logistics area that plans, operates and controls the flow and corresponding logistics information, acting in the area of ​​the return of post-sale and post-consumer goods to the business cycle or the production cycle. This process takes place through the reverse distribution channels, adding them values ​​of diverse natures: economic, service provision, ecological, legal, logistic, corporate image, among others (LEITE, 2010).

Reverse logistics is recognized by all companies as a lean production tool that contributes significantly to reducing environmental impacts and reducing operating costs. These findings suggest that reverse logistics also contributes to lean and green.

The company "Steel" develops, in its operation, a set of "best practices" that aims to meet environmental requirements, which are defined by the law or by its environmental management system ("Steel" web site, 2012), expansion and maintenance of green areas with native species, water reuse, waste, recycling of ferrous materials among others. According to the executive advisor of "Steel", recycling is an important process to the waste management of the company in which almost 80% of the waste generated by the business process is reuse, with a strict control over its implementation.

Another important discovery identified by most respondents (75%) was that the three companies make use of criteria and standards (ISO 14001 and OHSAS 18001) of Environmental sustainability in selecting their suppliers, in order to guarantee a reduction of the environmental impacts of all their supply chains (green supply chain management).

Gavronski, Balbinotti e Ferrer (2005) defend the importance of implementing the ISO 14001 standard and also point out the need to meet the requirements of stakeholders; improving the company image; legal requirements and the improvement of operational performance, as the main motivational factors that lead Brazilian organizations to adopt this certification.

When verifying how the practices of Lean and Green are considered in the strategic planning of the companies, it was found out that two, "Electric Power" and "Steel", consider the results obtained with the application of lean production and environmental management system within their annual strategic planning. They also define targets and indicators to measure these outcomes and evaluate the contribution of these tools for improving organizational productivity.

In a comprehensive overview of the sample, the respondents of the company "Industry" asserted that they realize the complementary concepts of "Lean" and "Green" and the benefits brought about by the reduction of waste. However, these results aren’t used in defining their strategic planning. They understand that the driver factor of their organizational strategies is identifying and meeting the requirements set by customers.

Most respondents agree that the implementation of Lean Production System contributes to the reduction of waste and to the minimization of costs and environmental impacts caused by the production process, as well as it uses the main tools (Kanban, Pokayoke, Cell Production and Visual Control) of this model in their operations in order to ensure better operational results and market differentiation.

Even in the "Industry", which reported that the questionnaire does not identify the applicability of lean in its production process, it was found that it uses this philosophy to the process control and waste reduction.

In the company "Industry’’, it was only identified environmental projects recycling and selective collection, as well as social projects with a focus on professional development of its employees, financial support for sporting activities and participation in annual profits.

For Godinho Filho and Fernandes (2004, pp. 15-16) "Lean Manufacturing is not a solution to all evils; its application will depend on the strategic objectives of the company in question, "however, it consists of a methodology that assists in the reduction of waste and with this, promotes the reduction of costs and the elevation of quality in the industrial processes. Even so, it needs a "maturation period", that is, the consolidation of the model, so that the cultural and financial results of its implementation can be identified”.

According to the results coming from the research and in the management reports of the three companies investigated, it was found that they all have mature and well-developed processes for improving EMS; they seek to improve quality of life of their employees and the community through environmental training programs and professional development; act on reducing environmental impacts, project-selective collection and recycling, and encourage the efficient use of natural resources.

Still, the findings obtained by the research identified the existence of complementarity between the concepts of "Lean" and "Green" though that does not allow systematic way to assess the degree of their contributions in reducing waste. These interactions in productive business environment are perceived by the researched subjects that highlight the benefits arising out of this relationship.

Therefore, the actions in this direction was presented as evidence, that the investigated companies seek to minimize the environmental impacts generated by their production processes in two of the three companies. In addition, companies ("Electric Power" and "Steel") take into consideration the results obtained by this synergy in their annual strategic planning and formulation of productivity goals.

From the results analyzed in the questionnaires applied, and in the managerial reports of the three companies researched, it was verified that all have a mature EMS and with well-developed improvement processes; seek to improve the quality of life of its employees and the community, through programs of environmental training and professional development; reduce the environmental impacts; use selective collection and recycling projects, as well as encouraging the efficient use of natural resources.

Still, the results found by the research identified the existence of complementarity between the concepts of "lean" and "green" although in a non-systematized way that allowed to evaluate the degree of their contributions in the reduction of waste. These interactions in the productive environment of the companies are perceived by the researched individuals that highlight the benefits derived from this relationship.