Global industry is undergoing major transformations with the genesis of a new paradigm known as the Internet of Things (IoT) with its underlying technologies. Many company leaders are investing more effort and money in transforming their services to capitalize on the benefits provided by the IoT. Thereby, the decision makers in public waste management do not want to be outdone, and it is challenging to provide an efficient and real-time waste management system. This paper proposes a solution (hardware, software, and communications) that aims to optimize waste management and include a citizen in the process. The system follows an IoT-based approach where the discarded waste from the smart bin is continuously monitored by sensors that inform the filling level of each compartment, in real-time. These data are stored and processed in an IoT middleware providing information for collection with optimized routes and generating important statistical data for monitoring the waste collection accurately in terms of resource management and the provided services for the community. Citizens can easily access information about the public waste bins through the Web or a mobile application. The creation of the real prototype of the smart container, the development of the waste management application and a real-scale experiment use case for evaluation, demonstration, and validation show that the proposed system can efficiently change the way people deal with their garbage and optimize economic and material resources.
The latest developments in the Internet, with its underlying technologies, smart sensors and communication technologies, provide the possibility of connecting machines, devices, software, and objects communicating among them without human intervention, thereby paving the way for a new paradigm called the Internet of Things (IoT).
One of the main definitions of IoT from researchers, practitioners and businessmen is that IoT is a dynamic and global network infrastructure, in which intelligent things, subsystems and individual physical and virtual entities are identifiable, autonomous, and self-configurable [1].
Several efforts and research works have been dedicated to IoT technologies, such as Radio-Frequency Identification (RFID) technologies, sensors and actuators, wireless mobile communication technologies, embedded systems and cloud computing technologies. These advances allow IoT technologies to bridge the gap between ubiquitous network-based devices and technologies that monitor and collect information from physical world observations and provide new services and applications used to improve the living conditions of people in many areas. Thus, the IoT can deliver significant savings, improve utilization of a city’s assets, increase process efficiency, and add productivity by directly linking low-cost technologies. Some examples of these applications are smart cities, homes and offices, logistics and distribution systems, healthcare, surveillance and security, the supply chain, manufacturing industry, etc. [2,3,4,5].
In smart cities, the efficient management of waste is a crucial challenge for the environment that IoT tends to address [6]. Waste management covers all the activities necessary for monitoring the waste generated in a city, from its beginning, when citizens produce their waste, through collection, transportation, and arrival at its final accommodation, which can be the landfill, incineration, or recycling. It has been a significant challenge for cities around the world [7]. Thus, in the absence of an effective and efficient solid waste management program, waste generated by urban activities, both industrial and domestic, can result in health risks and harm the environment [8]. Understanding of the waste generated, the availability of resources and the environmental conditions of a given society is essential for the development of an appropriate waste management system. Solid waste is defined as materials that no longer interest the original owner and are discarded. Good examples are organic waste (including kitchen waste and leftovers from garden pruning), paper, glass, metals, plastics, fabrics, and wood. Solid waste management is associated not only with generation control but also with the disposal of solid waste in a way that follows the best principles of health, economy and other considerations as to the environmental attitudes developed by citizens.
Compared with developed countries, citizens of underdeveloped countries suffer most severely from the impact of unsustainably managed waste, In Brazil, for example, 80 thousand tons of solid waste are disposed of inadequately every day, according to the United Nations (UN) [9]. In these countries, garbage is often disposed of inappropriately in rivers, streets or even in open incineration; these practices have severe consequences for human health, safety and the environment. Improperly managed waste can serve as a rich source of disease and contribute to global climate change through the generation of greenhouse gases, and even promotes urban violence with the degradation of urban environments. Proper waste management is essential for the construction of sustainable and habitable cities but remains a challenge for many developing countries and cities. Effective waste management often becomes costly, compromising municipal budgets. Operating this essential municipal service requires an integrated system that is efficient and sustainable [10].
This work proposes an efficient and real-time waste management model for cities, focused on a citizen perspective. The proposed system includes sensor technologies where waste information is collected from the smart bin (things), in real-time, and then transmitted, through the Internet, to an online platform where citizens can access and check the availability of the compartments scattered around a city. A real prototype of the smart container was created, evaluated, demonstrated, and validated, and is ready-mapped in a real solution. The main contributions of this paper are the following:
The remainder of this paper is organized as follows. Section 2 presents related work on waste management, showing the most relevant solutions available in the literature. Section 3 describes the proposal of this study (a solution that aims to optimize the waste management process), including the creation of hardware, software, and integrated communication. The results of the performance study of the proposed system through a real prototype deployment are analyzed in Section 4. Finally, the conclusion and future works are identified in Section 5.
The waste management system currently used in cities still follows an old and outdated model that no longer meets the needs of municipalities. It is inefficient and practiced through large fleets of collection trucks that travel daily long distances, often by unnecessary routes, where others are discovered, and with daily or weekly service schedules. These aspects bring unnecessary costs, waste of time and, more significantly, environmental damage, not only by the emission of gases from the burning of fossil fuel, which contributes to the greenhouse effect, but mainly by the contamination of soil and water resources due to poor waste management.
This paper proposes a solution that comprises hardware, software, and communication integrated into a solution that aims to optimize the management of the waste produced in cities through an approach that generates saving of the public money, contributes with the environment, and also encourages citizenship.
In terms of research methodology, this study follows an approach based on a case study performed through a real deployment of the proposed solution. The created solution (a real prototype of the smart container and waste management app, integrated through the In.IoT middleware) is shown, demonstrated, and validated through real experimentation. The proposed solution is described below.
To standardize the IoT segment or vertical, being supported by a reference architecture model is very important. Therefore, in the future, these waste management devices, which are called objects in IoT, can be connected and, therefore, the interoperability challenge is solved.
An architecture for IoT-technology-based applications is necessary when addressing factors such as scalability, interoperability, reliability, quality of service (QoS), etc. According to the authors of [2], there are several models and reference architectures available for IoT. Each research group or company describes its own, which often causes conflicts of ideas and makes the task of standardization more complex.
Many project models focus on a typical architecture based on needs analysis or on some layers that form a basic model of a reference architecture. The most basic approach only considers a three-layer architecture composed of application, network, and perception layers [24]. Figure 1 illustrates the basic layered architecture of the proposed solution.
Figure 1. Layered architecture for the waste management system.
These layers alternate according to the proposed model.
The IoT architecture perception layer is similar to the physical layer of the open systems interconnection (OSI) model, because it is based on the hardware level and has the responsibility of collecting physical information, processing and transferring it to the upper layers through secure channels. It applies technologies for the detection of parameters of physical characteristics through specific sensors, such as weight, temperature, humidity, etc. In addition, it performs the collection of object identification data, such as quick response codes (QR codes) and RFID.
The network layer is responsible for transferring the measured information in the perception layer to the upper layers, where the processing systems are located, and uses ZigBee, Z-wire, GSM, UMTS, Wi-Fi, Infrared, 6LoWPAN. In addition to the basic assignments, the network layer also performs the cloud computing process and the data management process.
The middleware layer is a layer of software or even a set of sublayers that work to interconnect components of the IoT that would not be possible to communicate otherwise, that is, as an interpreter. In addition to providing concurrency so that the application layer can interact with the layer of perception and ensure effective communication, it plays an important role in the development of new technologies.
The application layer does not directly contribute to the construction of an IoT architecture, but it is in this layer where the various services are built that interface with users, that is, where the interpretation and availability of the information occurs.
The system includes an applied solution where the compartments are monitored continuously by sensors, which inform, in real-time, the filling level of each one. These data are transferred to a storage and processing unit to serve as information, so that competent authorities can stipulate priority collection areas and collection paths with optimized routes and generate statistical data so the resources are employed adequately in regions with the highest demand for service. However, the main focus of the solution is to provide citizenship for residential users. Citizens can identify the compartments close to their home and know their level of usage in advance, via the Web or a mobile app. If the system recognizes unavailability at the nearest collection point, the user will be directed to discard his/her garbage at another available point and will receive the collection forecast from the previous bin, which allows the user to choose between a possible disposal at another location not so close, or even preserve the garbage at home so the disposal takes place at another time, after the municipal collection.
The My Waste Management system considers three main blocks, as shown in Figure 2. The first describes the smart bin, the second considers the IoT middleware integration, and the last block presents the user’s application.
Figure 2. Illustration of the system architecture.
Below, the whole system (hardware, software, and communication technologies) will be described, and it will be demonstrated also how it can be used to efficiently optimize waste management in cities.
The waste bin includes a container with a lid, and its enclosure is equipped with sensors such as the HC-SR04 module, an ultrasonic sensor responsible for measuring the level of waste filling present inside the compartment. This is significant within the solution, because through its operation it is possible to avoid the overflow of waste or excessive garbage deposit. The solution also includes a load cell module (load sensor) that measures the weight of the residues present in the compartment. It is characterized by a great importance within the system, since many residues have a small volume and significant mass. The load sensor is coupled to a specific driver, such as HX711, which amplifies the signal emitted by the load cell in addition to providing interconnection with the microcontroller.
The competence of these two modules is an ai
