Pollutant transport mechanisms and parameters in constructed subsurface flow wetlands. In recent years, there has been an increasing trend towards the application of constructed wetland wastewater treatment as a decentralized wastewater management solution. Small scale approaches for domestic wastewater treatment offer alternatives that adapt the different sustainability considerations including low cost design installation, operation and maintenance. The design of a constructed wetland should be not only environmentally sound but also economical. The research purpose is to gain an insight into its internal working with focus on the hydraulic regime. To achieve a better understanding of pollutant transport mechanisms and parameters in a sand bed, a physical horizontal sand column model and an experimental constructed subsurface flow wetland were developed. These studies provide new insights on the inner functioning of the constructed wetland and allowed to make recommendation for a constructed subsurface flow wetland design in the Mekong Delta.
Constructed Wetlands (CWs) are a wastewater treatment technology that inherits the purification potential of natural wetlands and optimizes it to comply with regulations for treated discharges. CWs have become an equally performing alternative to conventional wastewater treatment technologies of communities up to 2000PE, with lower energy and maintenance costs. Despite their potential, CWs lack reliability, which holds back their full deployment in the territory. This fact results from the lack of understanding on their internal functioning and because they are prone to clogging. The enormous diversity of CWs typologies and operation strategies, and the fact that they operate at the mercy of the environmental conditions, makes each CW unique on its kind, and experimental studies are usually only representative of the studied system. This fact makes mathematical models essential to study their functioning. Several models for CWs have proliferated in the last dozen years to provide supporting tools for their design and operation as well as more insight into the treatment processes. However, compared to models utilized in similar disciplines, CWs models are still in an embrionary stage. Accordingly, the objectives of the current work were to develop a CWs model able to describe the most common processes taking place within CWs, and to use this model to shed light on the internal functioning of these systems in the long-term. The model, named BIO_PORE, was built in COMSOL Multiphysics and can simulate subsurface flow and pollutants transport in porous media. It also implements the biokinetic model Constructed Wetlands Model number 1 (CWM1) to describe the fate of organic matter, nitrogen and sulphur and the growth of the bacterial groups found in CWs. The model was calibrated with experimental data of a year of operation of a pilot system. Two empirical parameters (Mcap and Mbio_max ) were used to improve the description of bacterial growth obtained with CWM1 and to include the effects of solids accumulation on bacterial communities. The effect of these two parameters was evaluated using local sensitivity analysis. The model was later used to unveil the dynamics of bacterial communities within CWs. In addition, a theory was derived from simulation results, which aimed at describing the most basic functioning patterns of CWs based on the interaction between bacterial communities and accumulated solids. At the end of the document a mathematical formulation is presented to describe bioclogging and a numerical experiment is carried out to showcase its impact on simulation results. The main outcome of the current work was the BIO_PORE model. This model was able to reproduce effluent pollutant concentrations measured during an entire year of operation of the pilot system. Parameters Mcap and Mbio_max proved essential to prevent unlimited bacterial growth predicted by CWM1 near the inlet sections of CWs. These two parameters were also responsible for the good fitting with experimental data. This was confirmed with the sensitivity analysis, which demonstrated that they have a major impact on the model predictions for effluent COD and ammonia and ammonium nitrogen. The theory derived from simulation results indicated that bacteria move towards the outlet with time, following the accumulation of inert solids from inlet to outlet. This result may prove that CWs life-span is limited, corresponding to the time after which bacterial communities are pushed as much towards the outlet that their total biomass is not able to provide effluents with acceptable quality. The inclusion of bioclogging was a requisite to reproduce the bacterial distribution and fluid flow and pollutants transport within CWs. More work on the BIO_PORE model is required and more experimental data is necessary to calibrate and validate its results.
This volume offers detailed information on the behaviour of various water pollutants, and on the principles and concepts of groundwater flow and transport. It will help readers to understand and execute the planning, supervision, and review of solute transport and groundwater modeling projects. The book also discusses the role and fate of elements that have been identified as major contaminants in surface and subsurface waters, and their adverse effects on ecology and human health. The book explores this theme throughout four sections – a. Understanding Soil-Water Systems, b. Fate and Transport of Pollutants, c. Physico-Chemical Treatment of Wastewater and d. Microbial Techniques Used to Decontaminate Soil-Water Systems. Introducing readers to a range of recent advances concerning the fundamentals of subsurface water treatment, it offers a valuable guide for teachers, researchers, policymakers, and undergraduate and graduate students of hydrology, environmental microbiology, biotechnology and the environmental sciences. It also provides field engineers and industrial practitioners with essential support in the effective remediation and management of polluted sites.
Wastewater Treatment by Reverse Osmosis Process provides a one-stop-shop for reverse osmosis (RO), outlining its scope and limitations for the removal of organic compounds from wastewater. This book covers the state-of-the-art on RO processes and describes ten RO process models of different features and complexities. It also covers the advanced model-based techniques for RO process operations, including various rigorous methods for process modelling, simulation, and optimization at the lowest energy cost, as well as advanced tools such as genetic algorithms for achieving the same. • Highlights different types of physico–chemical and biological wastewater treatment methods including hybrid systems • Provides an overview of membrane processes, focuses on different types of membrane processes for water treatment and explains characteristics of membrane modules • Introduces the importance and challenges of process modelling for simulation, design, and optimization and offers examples across various industries •Describes the concept of different types of genetic algorithms for process optimisation and provides the state-of-the art of the GA method in terms of its application in water desalination and wastewater treatment •Emphasizes economic aspects of RO processes for wastewater treatment With its focus on the challenges posed by an increasing demand for fresh water and the urgent need to recycle wastewater at minimum cost, this work is an invaluable resource for engineers and scientists working within the field of wastewater treatment.
A groundbreaking book on the application of the economic and environmentally effective treatment of industrial wastewater Constructed Wetlands for Industrial Wastewater Treatment contains a review of the state-of-the-art applications of constructed wetland technology for industrial wastewater treatment. This green technology offers many economic, environmental, and societal advantages. The text examines the many unique uses and the effectiveness of constructed wetlands for the treatment of complex and heavily polluted wastewater from various industrial sources. The editor — a noted expert in the field — and the international author team (93 authors from 22 countries) present vivid examples of the current state of constructed wetlands in the industrial sector. The text is filled with international case studies and research outcomes and covers a wide range of applications of these sustainable systems including facilities such as the oil and gas industry, agro-industries, paper mills, pharmaceutical industry, textile industry, winery, brewery, sludge treatment and much more. The book reviews the many system setups, examines the different removal and/or transformational processes of the various pollutants and explores the overall effectiveness of this burgeoning technology. This important resource: Offers the first, groundbreaking text on constructed wetlands use for industrial wastewater treatment Provides a single reference with summarized information and the state-of-the-art knowledge of the use of Constructed Wetlands in the industrial sector through case studies, research outcomes and review chapters Covers a range of industrial applications such as hydrocarbons/oil and gas industry, food and beverage, wood and leather processing, agro-industries, pharmaceuticals and many others Includes best practices drawn by a collection of international case studies Presents the latest technological developments in the industry Written for civil and environmental engineers, sustainable wastewater/water managers in industry and government, Constructed Wetlands for Industrial Wastewater Treatment is the first book to offer a comprehensive review of the set-up and effectiveness of constructed wetlands for a wide range of industrial applications to highlight the diverse economic and environmental benefits this technology brings to the industry.
Wetlands have been used for uncontrolled wastewater disposal for centuries. However, the change in attitude towards wetlands during the 1950s and 1960s caused the minimization of the use of natural wetlands for wastewater treatment (at least in developed countries). Constructed wetlands have been used for wastewater treatment for about forty years. Constructed wetland treatment systems are engineered systems that have been designed and constructed to utilize the natural processes for removal of pollutants. They are designed to take advantage of many of the same processes that occur in natural wetlands, but do so within a more controlled environment. The aim of this book is to summarize the knowledge on horizontal s- surface flow constructed wetlands (HF CWs) and objectively evaluate their treatment efficiency under various conditions. The information on this type of wastewater treatment technology is scattered in many publications but a comprehensive summary based on world-wide experience has been lacking. The book provides an extensive overview of this treatment technology around the world, including examples from more than 50 countries and examples of various types of wastewater treated in HF CWs.
Vertical flow constructed wetlands for wastewater and sludge treatment represent a relatively new and still growing technology. Vertical Flow Constructed Wetlands is the first book to present the state-of-the-art knowledge regarding vertical flow constructed wetlands theory and applications. In this book, you will learn about vertical flow systems with information about application and performance. Vertical Flow Constructed Wetlands also includes information on how different countries are applying the technology, with design guidelines to illustrate best practices worldwide. A focus on water conservation through reuse of treated water showcases the benefit of vertical flow construction, which has greatly increased the attractiveness of the technology in recent years. - All state-of-the-art knowledge regarding vertical flow constructed wetlands gathered in one book - A review of various constructed wetland approaches, including information about applications and performance, helps clarify what is currently known about constructed wetland principles and design - Discussion of how to manage the treated wastewater leaving the vertical flow for increasing biodiversity, providing food and habitat for birds, and producing harvestable biomass or crops - Includes case studies of constructed wetlands in developing countries
Constructed Wetlands for Water Quality Improvement is a virtual encyclopedia of state-of-the-art information on the use of constructed wetlands for improving water quality. Well-organized and easy-to-use, this book features contributions from prominent scientists and provides important case studies. It is ideal for anyone involved in the application of constructed wetlands in treating municipal and industrial wastewater, mine drainage, and non-point source pollution. Constructed Wetlands for Water Quality Improvement is a "must" for industrial and municipal water treatment professionals, consulting engineers, federal and state regulators, wetland scientists and professionals, ecologists, environmental health professionals, planners, and industrial environmental managers.
