This book sheds light on this global environmental issue and proposes solutions to reduce contamination through multi-disciplinary approaches. Water is considered a vital resource because it is necessary for all aspects of human and ecosystem survival. However, due to natural processes and anthropogenic activities, various pollutants have been added to the groundwater system. Among these, heavy metals are some of the most serious pollutants. Cd, a toxic heavy metal used in Ni-Cd batteries, the coloration of plastic and various discarded electronic products released into the water system causes serious health issues. The chronic exposure to Cd produces a wide variety of acute and chronic effects in humans.

The book addresses the entire water cycle. The focus is on new technologies/processes (especially in high performance biological treatment), energy recovery, water recycling and reuse. Recommendations with regard to the right technologies/processes for specific situations are provided and a wide range of case studies, especially in emerging markets. In addition, the most modern water terminology with more positive connotations is used. This is especially important in the field of direct and indirect potable reuse (DPR and IPR respectively).

Despite the strong economic growth of the last decades, our modern global society is facing the existential threat of climate change. It is now realized that the linear economic model is not sustainable in the long run and cannot sustain the life standards. The new circular economy approach that is already under discussion suggests the adjustment of our priorities and the re-orientation of the future infrastructure investments. In this context, we are looking for new, innovative and sustainable solutions to increase the resiliency of our societies, to protect and restore the ecosystems, and to maintain the necessary economic growth without further undermining the planet’s boundaries. The well-being of coming generations will depend on our ability to adapt our economies to this challenge. In particular, transforming today’s cities into sustainable cities is one of the main adaptations that will be necessary. A holistic approach looking at cities from a system’s perspective is neededto achieve this goal.

This contributed book, as a part of a series of CERES publications, provides a multi-regional and cross-sectoral analysis of the interlinkages, challenges, and emerging responses in the areas of water security, climate change, and food systems, especially in a context marked by severe implications of the COVID-19 pandemic, increased climate vulnerability of many regions already water stressed, and an ambitious global action aiming at curbing climate change and restoring ecosystem. In the first set of chapters, the water, food, and environmental/climate security nexus is explored theoretically and by reference to empirical research covering many regions and sectors. In another set of chapters, the impacts of climate change on water resources and water-stressed regions are identified along with their implications for food systems and security. Other chapters of the volume identify the emerging solutions to the nexus challenges, mainly adaptation and mitigation options, governance and management approaches, technological and economic solutions, innovative farming and water management practices, etc. Most chapters scheduled for publication address timely and future-oriented topics, are based on empirical research particularly done in water-constrained and climate vulnerable countries from Asia, Africa, and the MENA region, and provide policy-oriented inputs and recommendations to guide change processes at multiple scales.

Bioremediation is the use of biological interventions for mitigation of the noxious effects caused by pollutants in the environment including wastewater. It is very useful approach for a variety of applications in the area of environmental protection. It has become an attractive alternative to the conventional clean-up technologies that employ plants and their associated microorganisms to remove, contain, or render harmless environmental contaminants.