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      Natural-Based Solutions for Bioremediation in Water Environment

       Pascal Breil1, Marie-Noëlle Pons2, Gilles Armani1, Ranya Amer3, Harrison Pienaar4, Paul Oberholster5 and Philippe Namour1*

       ¹ INRAE, Centre Lyon Grenoble, Auvergne Rhône-Alpes, rue de la Doua, Villeurbanne, France

       ² CNRS-Université de Lorraine, Laboratoire Réactions et Génie des Procédés, rue Grandville, Nancy Cedex, France

       ³ City of Scientific Research and Technology Applications (SRTA-City), Department of Environmental Biotechnology, New Borg El Arab, Alexandria, Egypt

       ⁴ Council for Scientific and Industrial Research (CSIR), Smart Places, Pretoria, South Africa

       ⁵ University of the Free State, Centre for Environmental Management Faculty, Natural and Agricultural Sciences, Bloemfontein, Republic of South Africa, Hebei University of Engineering, Handan, People's Republic of China

       Abstract

The search for effective and sustainable techniques for the decontamination of polluted water bodies has led to significant progress over the last two decades with the emergence of the concept of bioremediation, i.e., the use of nature-based solutions (NBSs) to eliminate pollution. The sustainability of these processes is based on the availability of low-cost resources and community-wide acceptance of NBSs. The chapter begins presenting (1) the basic concepts of bioremediation in freshwater ecosystems, based on NBSs, and (2) the details about aquatic bioremediation structures used. It discusses (3) the different techniques and plants used, with published results in phycoremediation (4) and phytoremediation (5), followed by improvement of bioremediation (6), with physical-chemical and microbial activity stimulation techniques, and the development of electro- bioremediation based on a passive redox control of microorganisms. Then, it deals with the maintenance and biodiversity of constructed wetlands (CWs), (7 and 8) and the possible nuisances to be controlled. Finally, it deals with monitoring (9) and modeling of CWs (10). The chapter ends with the social acceptance of the installations in the landscape and the concepts used to integrate them at catchment scale (12). Case studies of applications in the field are used to illustrate the various points of the topic. The conclusion summarizes the important points and traces the directions for future progress. A bibliography, mostly published over the last 20 years but not exhaustive, completes the chapter.

      Keywords: Self-purification, eco-hydrology, constructed wetland, phytoremediation, bank filtration

1.1 Introduction

      Modern global lifestyle contaminates almost all compartments of the water cycle, both surface and groundwater, with organic matter (OM), nutrients, metals, as well as synthetic chemicals. Domestic and industrial wastewater discharges many endocrine disruptors as well as metals and pharmaceutical residues. Thus, minerals and organic components from domestic, agricultural, or industrial activities pollute water bodies. At the end of the 20th century, environmental degradation due to human activities led to awareness about the existence of societal benefits derived from ecosystems: ecosystem services. The impacts on ecological services could be ignored as long as the resilience of the ecosystems allowed it. However, the ecological footprint of human activity continues to grow. Local and reversible impacts have become global and difficult to reverse, revealing the limits of ecological systems to support human activity, with negative cascading effects, when alteration on one ecosystem service has negative consequences on one or more other services. A well-known example is that of water resources and their pollution. The European Water Framework Directive 2000/60/EC was a first level of response aimed at reducing the ecological footprint (WFD, 2000).

      In order to face these socio-environmental challenges, without aggravating the situation through the introduction of disruptive technologies, the European Commission promotes the use of management methods inspired by natural processes: nature-based solutions (NBS). The European Commission defines NBS as: “Solutions that are inspired and supported by nature, which are cost-effective, simultaneously provide environmental, social, and economic benefits and help build resilience” (Faivre et al., 2017). The chapter focuses mainly on publications from the last 20 years devoted to the NBS implementation in bioremediation in water environment.

1.2 Basic Principles

      1.2.1 Bioremediation

      Strictly speaking, the term bioremediation encompasses a set of remediation technologies based on the use of living organisms to degrade or extract pollutants from the waterbodies. Bioremediation technologies stimulate the natural processes of biodegradation (self-purification) and clean the polluted environment. They can be applied directly on site in the case of in-situ bioremediation, treating the contaminant on site, or remotely in the case of ex-situ bioremediation, where the contaminated soil or water is extracted for treatment at a facility near the polluted site, or elsewhere after transportation (EPA, 2013). Bioremediation techniques are sustained by natural processes of a physical-chemical and/or biological character by exploiting the natural purification capacities of living systems: NBSs, applied separately or in synergetic way (Daghio et al., 2017; Lofrano et al., 2017).

      Whether they are physical-chemical, microbial-