Nano and Bio-Based Technologies for Wastewater Treatment

Prediction and Control Tools for the Dispersion of Pollutants in the Environment

Elvis Fosso-Kankeu

• Publisher: Wiley-Scrivener
• Year: 2019
• Print ISBN: 9781119577096
• eBook ISBN: 9781119577058
• Edition: 1
• Topic: Physical Sciences
• Subtopic: Organic Chemistry

Presents recent challenges related to new forms of pollution from industries and discusses adequate state-of-the-art technologies capable to remediate such forms of pollution.

Over the past few decades the boom in the industrial sector has contributed to the release in the environment of pollutants that have no regulatory status and which may have significant impact on the health of humans and animals. These pollutants also referred to as "emerging pollutants", are mostly aromatic compounds which derive from excretion of pharmaceutical, industrial effluents and municipal discharge. It is recurrent these days to find water treatment plants which no longer produce water that fits the purpose of domestic consumption based on newly established guidelines. This situation has prompted water authorities and researchers to develop tools for proper prediction and control of the dispersion of pollutants in the environment to ensure that appropriate measures are taken to prevent the occurrence of outbreaks due to sudden load of these pollutants in the water system.

The chapters in this book cover a wide range of nano and bio-based techniques that have been designed for the real time detection of emerging contaminants in environmental water sources, geochemical models that are continuously improved for the prediction of inorganic contaminants migration from the mine solid wastes into ground and surface waters. Remediation strategies are also discussed and include effective techniques based on nanotechnology, advanced membrane filtration, oxidative and bio-degradation processes using various types of nanocatalysts, biocatalysts or supporting polymer matrices which are under advanced investigations for their implementation at large scale for the removal of recalcitrant pollutants from polluted water.

Nano and Bio-Based Technologies for Wastewater Treatment: Prediction and Control Tools for the Dispersion of Pollutants in the Environment is divided is two sections. The first section covers the occurrence of emerging pollutants in environmental water while the second section covers state-of-the-art research on the removal of emerging pollutants from water using sustainable technologies. A total of 13 chapters addressing various topics related to the two sections are essentially based on recent developments in the respective field which could have a significant impact on the enhancement of the performance of wastewater treatment plants around the world, and especially in developing countries where access to clean and safe water remains a daily challenge.

Part 1
OCCURRENCE OF EMERGING POLLUTANTS IN WATER AND POSSIBLE RISKS

Chapter 1
Geochemical Prediction of Metal Dispersion in Surface and Groundwater Systems

Martin Mkandawire

Chemistry Department, Cape Breton University, Sydney, Nova Scotia, Canada

Email: [email protected]

Abstract

Dispersion of contaminants in an aquatic system refers to a process by which dissolved phase concentrations are reduced by the spreading of the plume and hydrodynamic through mixing with cleaner, surrounding water. Thus, metal dispersion in the environment is very distinct and environment dependent but dictated by physical–chemical processes that influence sorption and redox reactions. The reduction in plume concentrations of metal contaminants by dispersion, for instance in groundwater flowing in aquifer sands and gravel, is a very weak process compared to the turbulent mixing processes that occur in the open channel flow of surface water systems like streams. In a nutshell, effective geochemical predictions of metal dispersion cannot ignore the geochemical, geotechnical background including the bedrock and material composition and properties, physical features like topography and the hydrological regime, as well as contaminant transport dynamics. Further, the climatic factors play a crucial role in the overall predictions. Prediction of metal dispersion is necessary in pollution-prone environments, like mining sites, for establishing early warning systems when the contaminants would reach receiving environments of interest, as well as designing preventive and remediation strategies. This chapter discusses fundamentals in designing effective predictions of metal dispersion in both surface and groundwater.

Keywords: Phreatic process, geochemical modelling, plume migration, advective transport, oxygen ingress, stored acidity, finite element

1.1 Introduction

The dwindling availability of potable water resources has resulted in increased measures to protect water sources, especially from pollution. However, the legacy of industrial development has negatively manifested through the increased content of metal in the environment. The mere presence of high levels of metals in the environment is not a concern unless there is a reasonable risk of exposure to humans or degradation of the environment where the metals are located is likely to occur. Therefore, the dissolution of metals from contaminant sources and dispersion into receiving water sources, where they become exposure pathways is an issue. Consequently, monitoring and predicting metal contaminant dispersion into the environment is an important component in both water management and pollution control.

Classic procedures for monitoring and predicting metal contamination dispersion are conducted through regular sampling for water quality analysis. For surface water, it involves setting representative sampling stations, usually in a gradient, on the water bodies of interest; it is more complex for groundwater because it also involves the monitoring of wells. The data from hydrochemical monitoring can indicate the potential enrichment of metals into a system from the metals’ sources. However, this information is temporal and spatial since it does not indicate metal dispersion in real time. Pertaining to the issues of complexity and time involved, it is often not possible to conduct sufficiently realistic sampling and laboratory experiments to predict the long-term behavior of the metal, especially of dispersion into the water systems [1, 2]. Geochemical models can be used to interpret and predict processes that may take place over timescales that are not directly achievable in sample analysis and experiments. Consequently, there has been a growth in the development of geochemical models which predict pollutant and metal dispersions into the environment. This development has generally gone hand-in-hand with advances in numerical techniques for solving complex mathematical problems as well as improvements in calculation speed and capability, and the general accessibility of computers [3, 4].

The accuracy in predicting metal dispersion into surface and groundwater systems has significant implications in water resource management, pollution control, and it can greatly impact the reasonability and scientific significance of pollution control strategies [5]. Developing effective geochemical prediction tools for metal dispersion requires a sound understanding of the prevailing hydrogeochemical processes and the behavior of the metal in the aquatic system. Metal dispersion depends solely on their inherent chemical properties vis-a-vis chemical form and speciation in the water, as facilitated by the prevailing hydrogeochemical processes. For instance, the complex nature of sediment–soil–water interactions in different hydrodynamic zones can produce a manifold of effects, including mobilization, concentration, and dispersion of metals at both short and long timescales [6]. Chemical erosion due to variations in natural climate and hydrodynamic conditions significantly influences the concentration of metals dissolved in water. Depending on their dissolved form and redox status, some metals form free or complex cations when dissolved in water while others, including some metalloids, are present as anions in their dissolved form [7]. Differences between groups of metals have important consequences for the partitioning of the metals among several dissolved and particulate phases, which are generally described by sorption of particulates, precipitation in minerals, and complexation in s...

Table of contents

• Cover
• Title Page
• Copyright
• Preface
• Part 1: Occurrence of Emerging Pollutants in Water and Possible Risks
• Part 2: Nano and Bio-Based Technologies for Wastewater Treatment
• Index
• End User License Agreement