Rapid growth of cities and industries in China is having  a dramatic impact on the environment. To counteract further decrease of water quality of rivers, lakes and groundwater bodies, an ambitious environmental remediation programme needs to be designed and brought into action. Intensive research and development activity are required to provide tailored solutions. The articles compiled in the book describe the current situation in China with respect to surface water quality and wastewater treatment, and provide results of specific research projects, leading the way to a China-specific up-to-date water treatment technology. Discussed are lessons to be learnt from the experience made in other countries, particularly with respect to regulations and management practices

The papers in this volume were originally presented at the 18th European Junior Scientists Workshop (EJSW), Portugal, on 8-11 November 2003 and at the 1st Asian Junior Scientists Workshop (AJSW), Malaysia, on 7-10 February 2004. The workshops were organised by the SS&PWG (Sewer Systems and Processes Working Group) of the IWA/IAHR Joint Committee on Urban Drainage. The two separate workshops were convened under the general themes of "Sewer Processes, Networks and Urban Drainage" and specific topics covered included integrated modelling of urban water systems; modelling of pollutant loads; calibration of models; bed-load transport; sewer pipe roughness; advection in sewers; anoxic processes; infiltration and exfiltration; runoff source control; pollutant loads; ventilation and oxygen uptake. From the 37 full papers presented at the two workshops, 16 papers have been selected by independent reviewers from the SS&PWG for publication in Sewer Networks and Processes within Urban Water Systems. They reflect rather well the variety of topics presented during both workshops, and bring the high-quality work of these junior authors to the wider audience it merits.

This book represents the outcome of the Second IWA Leading-Edge Conference held in Sydney, Australia in November 2004. Sustainability is a paradoxical concept. We know we want to protect the environment from human-induced change, yet ecosystems are dynamic, constantly changing and adapting in response to a multitude of factors, the combined effect and subtleties of which are probably well beyond human calculation. Furthermore, our conscious desire to protect the environment - which forces us to think of humans as sitting outside ecosystems - conflicts with the unavoidable fact that we are an unconscious actor within those ecosystems. We must also recognise that the goal of "protecting the environment" is not a clear-cut objective. Perhaps, because of its complexity and propensity to change, we cannot know what the fully protected environment would look like. Individual preferences too make the conceptualisation of an ideal state impossible; do we strive for an ecosystem in which we play a minor part - barely influencing natural outcomes - or one that is more actively managed and provides for our needs or wants? Neither this volume, nor the conference from which it draws, resolve the paradoxes described above. The papers presented here do, however, provide insight into the innovative thinking and practical projects undertaken across the globe that move us from patently unsustainable conditions to those in which our economic activity, impact on ecosystems and desire for positive social outcomes are in better balance.

Wastewater and drinking water treatment are essential elements of urban infrastructure. In the course of the last century there has been enormous technical development, so successful that for the general public in industrialized countries this infrastructure is hardly noticed. Nevertheless there is ongoing activity to further improve the existing processes. The IWA Leading Edge Technology conference held in Prague helped to stimulate this development and this book helps disseminate the results. A selection of presentations from the conference are included in this volume. Wastewater and drinking-water treatment are normally considered as two separate fields due to the very different boundary conditions that apply. Nevertheless several issues such as membrane processes, removal of micropollutants and water reuse are of crucial importance to both. This potential for cross-fertilization further enhances the value of this collection of high-quality articles that delineate the leading edge of research and development in water and wastewater treatment.

Aerobic Granular Sludge has recently received growing attention by researchers and technology developers, worldwide. Laboratory studies and preliminary field tests led to the conclusion that granular activated sludge can be readily established and profitably used in activated sludge plants, provided 'correct' process conditions are chosen. But what makes process conditions 'correct'? And what makes granules different from activated sludge flocs? Answers to these question are offered in Aerobic Granular Sludge. Major topics covered in this book include: Reasons and mechanism of aerobic granule formation       Structure of the microbial population of aerobic granules       Role, composition and physical properties of EPS       Diffuse limitation and microbial activity within granules       Physio-chemical characteristics       Operation and application of granule reactors       Scale-up aspects of granular sludge reactors, and case studies Aerobic Granular Sludge provides up-to-date information about a rapidly emerging new technology of biological treatment.

River Basin Restoration and Management is the result of two workshops that took place at the 4th IWA World Water Congress: The Restoration of Degraded River Basins and River Basin Management Using Machine Learning. The Restoration of Degraded River Basins set out to share experience in the institutional, policy, and public participation elements of restoration programmes, the 'soft' issues surrounding restoration of a degraded river basin and the development of the river basin plan. The resulting papers include a number of case studies from a variety of river basins in Israel, South Africa, United Kingdom, Australia and Central Europe. The River Basin Management Using Machine Learning workshop highlighted and compared the two different approaches to watershed management: the physically based modelling approach relying on the system physics versus the data driven modelling approach based on exploring the system 'data behaviour'. The workshop was motivated by the recent rapid advance in information processing systems. These have pushed the hydrological research community to explore the possibilities of using intelligent systems aimed at automatically-evolving models of natural phenomena. This is the discipline of machine learning (ML), the study of computer algorithms that improve automatically through experience.

As part of IWA's role to promote networking and career development opportunities for young researchers and professionals, IWA established the Young Researchers Conference (YRC) in 2002 as a biennial international forum for young water professionals to discuss current and future environmental concerns and network with peers from different research institutions, disciplines and countries. The selection of papers in this special issue of WEMS represents papers that were presented at the 3rd Young Researchers Conference (YRC06) held on the 24-26 May 2006 at Nanyang Technological University, Singapore. The 58 papers from 23 countries were selected from 238 submissions and illustrate various aspects of water and wastewater engineering, technology and management including chapters on: Wastewater Treatment Water Policy and Management Sludge Management and Waste Treatment Monitoring and Data Analysis Modelling Water Quality and Wastewater Treatment Wastewater Biotechnology

Rapid growth of cities and industries in China is having  a dramatic impact on the environment. To counteract further decrease of water quality of rivers, lakes and groundwater bodies, an ambitious environmental remediation programme needs to be designed and brought into action. Intensive research and development activity are required to provide tailored solutions. The articles compiled in the book describe the current situation in China with respect to surface water quality and wastewater treatment, and provide results of specific research projects, leading the way to a China-specific up-to-date water treatment technology. Discussed are lessons to be learnt from the experience made in other countries, particularly with respect to regulations and management practices

The papers in this volume were originally presented at the 18th European Junior Scientists Workshop (EJSW), Portugal, on 8-11 November 2003 and at the 1st Asian Junior Scientists Workshop (AJSW), Malaysia, on 7-10 February 2004. The workshops were organised by the SS&PWG (Sewer Systems and Processes Working Group) of the IWA/IAHR Joint Committee on Urban Drainage. The two separate workshops were convened under the general themes of "Sewer Processes, Networks and Urban Drainage" and specific topics covered included integrated modelling of urban water systems; modelling of pollutant loads; calibration of models; bed-load transport; sewer pipe roughness; advection in sewers; anoxic processes; infiltration and exfiltration; runoff source control; pollutant loads; ventilation and oxygen uptake. From the 37 full papers presented at the two workshops, 16 papers have been selected by independent reviewers from the SS&PWG for publication in Sewer Networks and Processes within Urban Water Systems. They reflect rather well the variety of topics presented during both workshops, and bring the high-quality work of these junior authors to the wider audience it merits.

This book represents the outcome of the Second IWA Leading-Edge Conference held in Sydney, Australia in November 2004. Sustainability is a paradoxical concept. We know we want to protect the environment from human-induced change, yet ecosystems are dynamic, constantly changing and adapting in response to a multitude of factors, the combined effect and subtleties of which are probably well beyond human calculation. Furthermore, our conscious desire to protect the environment - which forces us to think of humans as sitting outside ecosystems - conflicts with the unavoidable fact that we are an unconscious actor within those ecosystems. We must also recognise that the goal of "protecting the environment" is not a clear-cut objective. Perhaps, because of its complexity and propensity to change, we cannot know what the fully protected environment would look like. Individual preferences too make the conceptualisation of an ideal state impossible; do we strive for an ecosystem in which we play a minor part - barely influencing natural outcomes - or one that is more actively managed and provides for our needs or wants? Neither this volume, nor the conference from which it draws, resolve the paradoxes described above. The papers presented here do, however, provide insight into the innovative thinking and practical projects undertaken across the globe that move us from patently unsustainable conditions to those in which our economic activity, impact on ecosystems and desire for positive social outcomes are in better balance.

Wastewater and drinking water treatment are essential elements of urban infrastructure. In the course of the last century there has been enormous technical development, so successful that for the general public in industrialized countries this infrastructure is hardly noticed. Nevertheless there is ongoing activity to further improve the existing processes. The IWA Leading Edge Technology conference held in Prague helped to stimulate this development and this book helps disseminate the results. A selection of presentations from the conference are included in this volume. Wastewater and drinking-water treatment are normally considered as two separate fields due to the very different boundary conditions that apply. Nevertheless several issues such as membrane processes, removal of micropollutants and water reuse are of crucial importance to both. This potential for cross-fertilization further enhances the value of this collection of high-quality articles that delineate the leading edge of research and development in water and wastewater treatment.

Aerobic Granular Sludge has recently received growing attention by researchers and technology developers, worldwide. Laboratory studies and preliminary field tests led to the conclusion that granular activated sludge can be readily established and profitably used in activated sludge plants, provided 'correct' process conditions are chosen. But what makes process conditions 'correct'? And what makes granules different from activated sludge flocs? Answers to these question are offered in Aerobic Granular Sludge. Major topics covered in this book include: Reasons and mechanism of aerobic granule formation       Structure of the microbial population of aerobic granules       Role, composition and physical properties of EPS       Diffuse limitation and microbial activity within granules       Physio-chemical characteristics       Operation and application of granule reactors       Scale-up aspects of granular sludge reactors, and case studies Aerobic Granular Sludge provides up-to-date information about a rapidly emerging new technology of biological treatment.

River Basin Restoration and Management is the result of two workshops that took place at the 4th IWA World Water Congress: The Restoration of Degraded River Basins and River Basin Management Using Machine Learning. The Restoration of Degraded River Basins set out to share experience in the institutional, policy, and public participation elements of restoration programmes, the 'soft' issues surrounding restoration of a degraded river basin and the development of the river basin plan. The resulting papers include a number of case studies from a variety of river basins in Israel, South Africa, United Kingdom, Australia and Central Europe. The River Basin Management Using Machine Learning workshop highlighted and compared the two different approaches to watershed management: the physically based modelling approach relying on the system physics versus the data driven modelling approach based on exploring the system 'data behaviour'. The workshop was motivated by the recent rapid advance in information processing systems. These have pushed the hydrological research community to explore the possibilities of using intelligent systems aimed at automatically-evolving models of natural phenomena. This is the discipline of machine learning (ML), the study of computer algorithms that improve automatically through experience.

As part of IWA's role to promote networking and career development opportunities for young researchers and professionals, IWA established the Young Researchers Conference (YRC) in 2002 as a biennial international forum for young water professionals to discuss current and future environmental concerns and network with peers from different research institutions, disciplines and countries. The selection of papers in this special issue of WEMS represents papers that were presented at the 3rd Young Researchers Conference (YRC06) held on the 24-26 May 2006 at Nanyang Technological University, Singapore. The 58 papers from 23 countries were selected from 238 submissions and illustrate various aspects of water and wastewater engineering, technology and management including chapters on: Wastewater Treatment Water Policy and Management Sludge Management and Waste Treatment Monitoring and Data Analysis Modelling Water Quality and Wastewater Treatment Wastewater Biotechnology