# A Distributed Architecture for Smart Recycling Using Machine Learning
## 1 Introduction  
According to the 2018 Revision of World Urbanization Prospects produced by the Population Division of the UN Department of Economic and Social Affairs (UN DESA) today 55% of the world's population lives in urban areas, a proportion that is expected to increase to 68% by 2050 [1]. One of the biggest problems of urbanization and industrialization is the extraordinary rise in the generation of municipal solid waste (MSW) all over the world [2]. According to the World Bank's review report [1], in 2012, the global MSW generation levels were around 1.3 billion tons per year. This figure is expected to reach 2.2 billion tons per year by 2025. It is a global issue in terms of environmental contamination, social inclusion, and economic sustainability [3], which requires integrated assessments and holistic approaches for its solution [4]. Except this degradation in the environment we should also highlight the differences between developing big cities and rural areas, where management issues have a great variety, regarding the amount of waste generated and the SW management (SWM) facilities available [5]. While MSW itself may have a negative influence on the economic development, recycling of MSW has the prospect of achieving economic and environmental benefits [6]. In general, gross domestic product (GDP), population, and income are major factors. In recent years, some researchers have shown that goods consumption level is an important factor affecting the MSW volume [7]. Solid waste management is inevitably linked to environmental impacts on the planet and their consecutive economic consequences [8]. Globally, solid waste contributes to climate change and constitutes one of the largest sources of pollution in oceans. In low- and many middle-income countries, inadequate waste collection and uncontrolled dumping or burning of solid waste are still anunfortunate reality, polluting the air, water, and soil. When waste is burned, the resulting toxins and particulate matter in the air can cause respiratory and neurological diseases, among others [8]. For a sustainable future, it is vital to develop an effective recycling system. Recycling plays an important role in environmental and economical aspects of our planet. In developing countries, MSW recycling relies on household separation via scavengers and collectors who trade the recyclables for profit [9; 10] and the communities are more active in recycling program [11]. Choosing the proper management of MSW provide s sustainable environment and reduce direct and indirect health risks for humans [12]. Nowadays, researchers suggest to manage MSW a sustainable recycling method and waste reusing is required [13; 14]. Using these methods, we reduce the amount of produced waste which causes multiple problems to the environment and at the same time they help the municipals or the waste managers to save significant financial, natural and energy resources [15]. There are many different techniques, such as mechanical and chemical sorting, available in developed countries for automatic waste sorting [16]. Nonetheless, there are many opportunities to improve the procedure of waste recycling mostly in developed countries, utilizing cutting-edge technologies. Moreover, a noteworthy metric is that the municipal recycling rates both in the USA and in the European Union are around 34% and 46,4%, respectively, which are significantly lower than the proposed recycling rate of 75% [17; 18]. In the developing countries, the number of recycling rates are really low. For example, in Nepal about 5% of MSW are recycled [19] and according to the publication of Asian Development Bank [20] only six municipalities out of 58, use sanitary landfill sites for final disposal, and 45 are practicing open dumping, including riverside and roadside. Furthermore, having a lack of public awareness, and poor management by municipalities the environmental problems have intensified in towns in Nepal, including unsanitary waste management and disposal.