**Author details**

*Sustainability Assessment at the 21st Century*

cities" as ultimate sustainability goals.

land reclamation, urbanization process, biodiversity loss, waste production, and plastic pollution are likely to increase to alarming levels. Both developed and

emerging economies must cope with effects of climate change, water shortage risks, industrial pollution, food security, demographic challenges, and socioeconomic inequalities. In this context, linear economy is clearly unsustainable in the medium and long terms, and shifting transition toward circular economy is quite necessary. This type of economy aims to cut as much as possible the natural resource depletion through reusing of secondary materials and closing the production and consumption loops by avoiding further waste generation and their disposal in landfills. In fact, waste management sector must be replaced by resource management (e.g., "end of waste"), and in this regard, a new paradigm is born such as "zero waste

The 3R policy (reduce-reuse-recycle) based on waste hierarchy concept (where

New digital technologies and Internet networks provide new tools for urban areas to increase their resource efficiency and reduce their ecological footprint that is becoming the so-called smart cities. A key aspect is to use the "Internet of things" (IoT) and big data to manage future megacities in a sustainable manner. According to Ellen McArthur foundation, "A circular economy is based on the principles of designing out waste and pollution, keeping products and materials in use, and regenerating natural systems" [9]. In other words, circular economy plays a key role in sustainability of cities and rural communities. EU policies recognize the key role of future circular economy in Europe by dedicating a special package document [10] . This will enforce waste reduction targets and high rates for packaging materials such as plastic, glass, paper and cardboard, wood, aluminum, and ferrous materials with specific deadlines for 2025 and 2030. The ultimate goal is to reach 70% of packaging materials by 2030 and recycling 65% of municipal waste stream by 2035 [11]. On the other side, many developing countries must upgrade their waste management infrastructure and increase the collection efficiency in the context of rapid urbanization and demographic explosion expected to happen in Africa and Asia. Developed countries must invest and expand their waste recovery and recycling facilities and stop the export of packaging waste or e-waste items into developing countries (e.g., Malaysia, Indonesia, Ghana, and so on). Urban mining, which focuses on recovery process of valuable materials from used items (e.g.,

landfill and waste incineration are regarded as the least favorable options) is supplemented by product life expansion alternatives (repair-recovery-refurbishrepurpose-remanufacture) and to rethink our consumption patterns and to refuse to buy nonrecyclable items. These actions are more suitable than material recycling where additional raw materials and energy are needed for making new products. However, secondary materials and renewable energy sources should feed the new circular economy system instead of raw materials and fossil fuels. Composting of biowaste fraction or anaerobic digestion must be used to produce organic fertilizers and biofuels instead to be landfilled. Upcycling or creative reuse and sharing economy are other mechanisms that lead to responsible consumption patterns. The circular economy is strongly related to SDG9, industry, innovation, and infrastructure; SDG11, sustainable cities and communities; and SDG12—responsible production and consumption. Also, circular economy is interconnected to green economy (promoting clean energy sources, sustainable waste management practices, organic agriculture, etc.) or blue economy (sustainable management of marine resources and conservation). Full access of the population (urban and rural) to improved sanitation, solid waste, and wastewater management practices is critical to fulfilling SDG3 (good health and well-being), SDG6 (clean water and sanitation), and SDG10 (reducing inequalities) and to be able to make transition from linear to

**6**

circular economy.

María José Bastante-Ceca1 \*, José Luis Fuentes-Bargues1 , Mihai Florin-Constantin2 , Corneliu Iatu3 and Levente Hufnagel4

1 GIDDP, Departamento de Proyectos de Ingeniería, Universitat Politècnica de València, Valencia, Spain

2 Department of Research, Faculty of Geography and Geology, "Alexandru Ioan Cuza" University, Iasi, Romania

3 Department of Geography, Faculty of Geography and Geology, "Alexandru Ioan Cuza" University, Iasi, Romania

4 Faculty of Agricultural and Environmental Sciences, Laboratory of Biometrics and Quantitative Ecology, Institute of Crop Production, Szent István University, Gödöllő, Hungary

\*Address all correspondence to: mabasce1@dpi.upv.es

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
