Keywords

1 Introduction

The intense activity of the construction sector in the European Union, in recent years and specifically in Spain, is giving rise to the generation of huge volumes of Construction and Demolition Waste (CDW). Specifically, in 2020, 4.8 tons of construction and demolition waste per EU inhabitant, from out of which 39.2% of the waste was recycled and 32.2% were deposited in landfills [1]. Therefore, new initiatives are emerging in Europe to transition to a more efficient circular model that shifts toward the minimization, recycling, and reusing of CDW. In this regard, developing new regulations and policies, decreasing the exploitation of natural resources, optimising production processes, establishing commercial competitiveness for recovered and recycled building materials, and diminishing the generation of CDW throughout the construction process are actions aligned with circular economy that must be considered by government agencies and private companies active in the construction sector to implement and accomplish best practices. Furthermore, the EU member states have been drafting specific regulations for several years to establish a legal framework for the production and handling of CDW and boost the circular economy in the construction industry [2–5]. Among all the measures required in Spain, it should be highlighted that two written reports are needed. One is presented during the design phase of the project (Waste management report (WMR)) and the second during the planning of the construction works (Waste management plan (WMP)).

In addition, it is increasingly common that current projects are designed considering the criteria of environmental certificates which are currently on the market such a BREEAM, LEED, VERDE, etc. However, other environmental certificates which are more especial and consider particular issues for waste prevention and circular economy are still scarce [6]. For this reason, large construction companies are implementing Environmental Management Systems (EMS), seeking the implementation of best environmental practices in their work [7]. However, the vast majority of construction companies (small and medium companies) are still very far from adopting measures to promote CDW minimization and implement circular economy criteria. In this sense, the development of tools for CDW estimation which help to plan an adequate CDW management and of a specific section in the EMS of the construction companies, incorporating best practices for CDW management–, are essential to achieve construction works with zero waste generation.

This situation has been of great interest to researchers in the field that have paid special attention to CDW management and minimisation in recent years, specially during the design stage [7]. Best practices during the design can be clustered into five strategies: design for deconstruction; design for adaptability and flexibility; design to standardise; design recycled materials; and design for waste prevention.

  • Designing for deconstruction includes strategies [8], such as: Develop and design a deconstruction plan already in the design process, allowing, when possible, parallel disassembly; Use mechanical joints instead of other types of joints; and Avoid the use of binders, adhesive, resin, and secondary finishes.

  • Design for adaptability and flexibility; by using open spaces and regular shapes.

  • Design to standardize, using simple, modular designs, avoiding complex shapes and also the use of prefabricated materials [9].

  • Desing recycled materials: Use of materials with high recycled content [10] or reuse materials within construction work. Detecting activities that can incorporate reusable materials from the site itself.

  • Desing for waste prevention, including a wide range of specific strategies such as:

  • The use of waste management plan templates [11];

  • Waste prediction tools [12,13,14];

  • Promote construction systems that generate less waste [9, 15];

  • Development of detailed projects to minimize design changes and errors.

  • Increase coordination and communication → using BIM tools [16, 17].

  • Planning waste management—by implementing onsite best practices.

One of the key strategies for preventing CDW generation is planning waste management during the execution of the work, incorporating best practices such as:

  • CDW estimation and follow-up (type and quantity) [18, 19].

  • Purchase of bulk materials to reduce packaging [20].

  • Source separation [21]

  • Set the time of the materials’ reception, according to the construction site.

  • Follow the manufacturer's instructions on the transportation and storage of materials.

  • Using small containers in work areas [22].

  • CDW training [23]

  • Control and follow-up [24].

Finally, although there are numerous guides and manuals of best practices for CDW management, no references have been found implementing these measures in the Environmental Management System of construction companies. Furthermore, even though best practices regarding CDW management have been suggested and studied, specifying these practices according to the type of construction and the different waste categories generated remains a research to be performed. Therefore, this work aims to improve current Integrated Quality Management Systems (IQMS) by determining a specific CDW management system (CDWMS) for construction sites, providing consistent measures to prevent CDW generation in order to achieve circular construction projects.

2 Methods

Despite the CDWMS should include the entire building lifecycle—from the design stage until deconstruction—the scope of the CDWMS developed here has been limited to the building construction stage. However, a procedure to develop the CDW Management Report, written in the design phase—is also considered, as it has a direct connection with the document CDW Management Plan. Moreover, CDWMS should be a useful and operational tool for the construction agents of the company. To do so, the proposed CDWMS follows the same format and structure as commonly used IQMS [18]. The content and structure of each procedure were established after analyzing the IQMS procedures of several Spanish construction companies.

Finally, a procedure was chosen to be implemented in a real construction company. First, several meetings with the construction company were established in order to choose the procedure to be implemented and the reasons that led to his selection. After two years of implementation, an interview was carried out with the Head of Quality and Environment of the Company and the technician responsible for carrying out the procedure, in order to know the advantages and drawbacks encountered after its implementation and to identify potential areas for improvement. Throughout the interview, the agents answered the following questions: In how many construction sites has the procedure been implemented? What advantages/drawbacks were found after implementing the procedure? These advantages/drawbacks were found in all the construction sites? Can you suggest areas for improvement? and Based on your opinion, which procedure will be the next to be implemented? Why?

3 Results and Discussion

The CDWMS proposed here follows one of the eight main principles of quality management, i.e., management based on Procedures. The procedures define the activities needed to achieve a proper CDW management and are normally structured one or more procedures in order to describe and facilitate the proper management of waste generated on site. Each procedure contains several forms, which are Word or Excel documents. The CDWMS proposed unfolds in eight procedures (Fig. 2.1).

Fig. 2.1
A process map of the C D W management system with design and construction phases includes the processes of development of the document C D M management report and plan, C D W organization, communication, staff training, C D W control, control of the documents, and evaluation of the system.

General structure of the Construction and Demolition Waste Management System (CDWMS)

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Procedure 1: Development of the CDW Management Report: This procedure is divided into eleven forms. The CDW management report will be defined once all the forms are completed:

  • Form PR1.1/0: Introduction. This form describes general issues of the construction site, the Company, and the different regulations.

  • Form PR1.1/1: Description of work. This form describes: type of construction (new/refurbish), construction site address, number of dwellings, total built area, etc.

  • Forms PR1.1/2 and PR1.1/3: CDW quantification. This form identifies and quantifies the amount of each waste category expected to be generated both in weight and volume, as described by RD 105/2008.

  • Form PR1-1/4: CDW management. This form describes the percentages of each waste category that will be allocated to each management option (reuse, recycling, recovery, or disposal).

  • Form PR1.1/5: Best-practise measures for CDW minimization. This form must define all the measures to be used for reducing the amount of CDW generated on site. This should be done to consider the possible waste to be generated in each activity of the work and prioritizing the waste to be generated in larger quantities.

  • Form PR1.1/6: Best-practise measures for CDW segregation. This section should define all the measures that will be used to separate different waste categories.

  • Form PR1-1/7: Drawing plans. This form allocates in the working site the installations and storage sites needed for a proper segregation of CDW.

  • Form PR1-1/8: Technical specifications. This form describes the Technical Specifications for Waste Management.

  • Form PR1-1/9: CDW management cost.

  • Form PR1-1/10: Approval of the CDW Management Report. This form must be approved by the Company’s Director of Environment and the project developer.

Procedure 2: Development of the CDW Management Plan: This document specifies the CDW Management Report document, which is more general, to a specific construction site. This procedure is also divided into eleven forms as in Procedure 1 numbered as Form PR1.2/0.

Procedure 3: CDW organization: This Procedure describes how to organise CDW management generated on site.

  • PR 3.1: Assigning responsibility. The people responsible for each action on waste management are designated in PR 3.1 by completing Annex ANX PR3.1/1.

  • PR 3.2: Relationship with suppliers and contractors. When contacting suppliers and contractors, procedure PR 3.2 will be followed, establishing the minimum requirements and best practices for suppliers and subcontractors by filling three annexes: ANX PR3.2/1: Environmental Responsibility Doc, ANX PR3.2/2: Clauses related with CDW and ANX PR3.2/3: Request for CDW management documentation.

  • PR 3.3: Implementation of segregation measures. By filling in and using labels in Annex ANX PR3.3/1: Tags to collect CDW when segregating waste.

  • PR 3.4: Inert and nonhazardous waste management and PR 3.5: hazardous waste management. In order to manage the waste generated, one of the two procedures will be followed, depending on the type of waste.

Procedure 4: Communication: consists of a single procedure which describes the methodology to communicate CDW Management issues between the different construction stakeholders.

Procedure 5: Staff training: consists of a single procedure which describes CDW training for construction workers and staff. The training activities planned are recorded in Annex ANX PR5.1/1 “Training programme for CDW management”. Subsequently, those responsible for the training activities will make a request, following Annex ANX PR5.1/3 “Request training”, to the Head of Human Resources stating the reasons for training, the proposed training activities, and the staff concerned. Finally, the Head of Human Resources will have a personal record of all training activities of the Company by completing Annex ANX PR5.1/2 “personal training table”.

Procedure 6: CDW control: Controlling CDWMS documents is essential to achieve correct CDW management [19]. Therefore, the CDWMS has a specific tracking procedure based on the development of traceable records by filling out the forms. The procedure contains four procedures in order to describe how to monitor and control the CDW management carried out on site.

  • PR 6.1: Tracking of CDW management. This procedure provides the methodology for monitoring and controlling various activities related to waste management. For this, the form 6.1/1 needs to be completed. The best practices anticipated in the CDW management plan will be scored and determined if they are being implemented or not.

  • PR 6.2: Management of nonconformities. This procedure describes how to identify non-conformities and implement corrective and preventive actions. To this end, the following three annexes need to be completed: ANX 6.2/1: Evidence Report; ANX 6.2/2: Report of non-conformities and ANX 6.2/3: List of reports of non-conformities.

  • PR 6.3: Assessment of staff towards CDW management. This procedure establishes the attitude of the process for assessing the staff and evaluates their commitment to the CDW environmental management policies.

  • PR 6.4: Tracking CDW generation. This procedure provides the methodology for recording the quantities of waste generated on site, allowing one to identify, through the actual on-site data, the volume and the weight of the CDW generated daily at each construction site. For this, each time a waste container leaves the site Excel file of Annex ANX6.4/1: The generated CDW registration is completed, using the delivery notes corresponding to when the work containers left the site (service delivery), as well as the delivery notes issued by the waste manager once the heavy containers arrived at the recycling plant (receipt of admission).

Procedure 7: Document control. This procedure describes the process to ensure the identification, maintenance and storage of the different documents and files generated in the CDWMS.

Procedure 8: Evaluation of the system. Consists of a single procedure “PR 8.1: Audit” which describes how to evaluate the CDWMS developed in order to test if the system is effective and appropriate to achieve the goals and targets of the company.

3.1 Structure of the Procedures

It is important that the CDWMS developed here uses a standard structure for the different processes to facilitate the identification and understanding of the information contained in the CDWMS. To determine the structure of the procedures, various internal quality management systems from four construction companies were taken as examples. Based on the findings, the procedures developed in the CDWMS follow a standardised structure: Aim; Scope; References; Responsibilities; Description/Phases; Flowchart; Changes to the procedure; and Annexes.

3.2 Implementation of the Procedure

Procedure 6.4 “Tracking CDW generation” was chosen to be implemented in the company, because:

  • Particular CDW generation ratios are obtained after its implementation, which serve as the basis for calculations of Procedures 1 and 2 in order to develop the CDW Management Plans and Reports.

  • It can be immediately incorporated into the company organisation.

The company has implemented this procedure in all their construction works (a total of fifty), not only in residential building construction works but also in nonresidential projects. According to the benefits found during its implementation, the company highlighted that this procedure allows determining accurate CDW quantification ratios (amount CDW per m2 of built surface), in order to set particular and more reliable indicators. The establishment of these indicators helps to develop CDW Management Plans and Reports in order to achieve a higher adjustment in CDW management costs. Another advantage is that no construction agents had a high resistance or opposition to implement the method. However, the company highlighted that some construction teams were more involved than others. In fact, the company organises an annual award for the best construction team of the year. This award considers and evaluates, among other factors, the CDW management carried out on site.

The main drawbacks found during its implementation were focused on reorganization, as CDW management documents control—i.e., the delivery notes issued by the waste manager once the heavy containers arrived at the recycling plant (receipt of admission)—was relocated from the site to the central office. Initially, the delivery notes were received at each construction site and each construction team was responsible for completing ANX6.4/1 “CDW Registration”. After a trial period, the Company observed that there was a lack of coordination to complete and return to the central office the annexes. Therefore, to solve this, the company decided to centralise the procedure at the central office. To this end, admission receipts from all the works were received at the central office in order to improve the control and coordination of CDW data collection. However, this change in the company’s organization led to an increase in time and resource consumption, as the company had to assign an employee to fill out the ANX6.4/1 “CDW Registration” (ie the monthly CDW data generation) for each site. In this regard, the company considers it essential that waste managers provide CDW information in digital format (Excel file or similar) rather than sending them on paper.

Furthermore, the company considered that the completion of the Excel file containing Annex ANX6.4/1 should be simpler, so they developed a software application that automates the process. The computer tool shows a summary of the CDW containers generated to date (marked with a red arrow) and specific information about each CDW container. Finally, the information is automatically incorporated into the Excel file ANX6.4/1 “CDW registration”.

Today, the tool does not allow entering the construction work activities running at that time: structure, masonry, and finishings. This information is manually included, as planned in the original procedure. However, the company considers automating this information in the future. In short, the area of improvement proposed and developed by the company is geared towards automation of the process. Finally, the company considered that the next procedure to be implemented would be 5.1 “Staff training”, which they consider fundamental to achieving a proper CDW management on site.

4 Conclusions

A CDW management system for newly built residential building constructions has been developed, based on eight processes with their own procedures, formats, and annexes. This CDW management system can be implemented in the construction companies in order to help CDW management. In general, this CDW management system establishes control, preventive, and corrective measures on aspects that have previously been identified as the most significant for reducing potential problems.

The procedure ‘PR6.4 CDW generation” was chosen as the first procedure of the CDW Management System to be implemented in the company. This procedure allows to obtain rigorous CDW quantification ratios and also helps to achieve greater adjustments for their CDW management costs. Stablishing personal CDW ratios helps them with the development of CDW management plans and Reports. The area of improvement proposed and developed by the company focuses on automating the process, in order to obtain a complete tool that allows easier filling. Finally, procedure PR5.1 ‘Staff training’ can be the next procedure to be implemented, because the training on CDW is essential in order to achieve proper on-site CDW management.

Finally, the results obtained revealed that the CDW Management System developed allows to improve and optimise construction processes, favoring the control and savings of raw materials through reuse and minimization of waste, and giving CDW responsibilities to their employees and managers. Therefore, determining and implementing an on-site CDW Management System, integrated with the EMS and in turn with the QMS of the companies, will definitely improve existing management systems.