Urban Wastewater

by Professor Poul Harremoes Environmental engineering has been a discipline dominated by empirical approaches to engineering. Historically speaking, the development of urban drainage structures was very successful on the basis of pure empiricism. Just think of the impressive structures built by the Romans long before the discipline of hydraulics came into being. The fact is that the Romans did not know much about the theories of hydraulics, which were discovered as late as the mid-1800s. However, with the Renaissance came a new era. Astronomy (Galileos) and basic physics (Newton) started the scientific revolution and in the mid-1800s Navier and Stokes developed the application of Newtons laws to hydrodynamics, and later, St. Venant the first basic physics description of the motion of water in open channels. The combination of basic physical understanding of the phenomena involved in the flow of water in pipes and the experience gained by "trial and error", the engineering approach to urban drainage improved the design and performance of the engineering drainage infrastructure. However, due to the mathematical complications of the basic equations, solutions were available only to quite simple cases of practical significance until the introduction of new principles of calculation made possible by computers and their ability to crunch numbers. Now even intricate hydraulic phenomena can be simulated with a reasonable degree of confidence that the simulations are in agreement with performance in practice, if the models are adequately calibrated with sample performance data.

This volume offers a detailed overview of currently applied and tested wastewater treatment technologies and the integration of advanced processes to remove trace organic contaminants and microorganisms. It discusses the potential of enhanced biological treatment to produce effluent suitable for reuse, new processes for urban wastewater disinfection and the reduction of antibiotic resistant bacteria, as well as the effect of advanced oxidation processes on wastewater microbiome and chemical contaminants. It also presents membrane bioreactors, moving bed bioreactors, light and solar driven technologies, ozonation and immobilised heterogeneous photocatalysis and provides an evaluation of the potential of constructed wetlands integrated with advanced oxidation technologies to produce wastewater safe for reuse. Furthermore, the volume discusses water reuse issues and standards, the status of membrane bioreactors applications, and the treatment of reverse osmosis concentrate for enhanced water recovery during wastewater treatment. Finally, it presents recent developments in potable water reuse and addresses various important issues in this framework, like the proper protection of public health, reliability and monitoring. This volume is of interest to experts, scientists and practitioners from various fields of research, including analytical and environmental chemistry, toxicology and environmental and sanitary engineering, as well as treatment plant operators and policymakers.

Farming communities in water-scarce regions increasingly practice the use of urban wastewater in agriculture. Untreated urban wastewater is generally considered unacceptable for direct use because of potential health risks. However, in many parts of the world, poor farmers in peri-urban areas use untreated wastewater. This situation is considered likely to continue even in the foreseeable future due to the high investment cost associated with the installation of treatment facilities.

Water pollution caused by wastewater persists despite three decades of effort to clean up European surface waters and despite the requirements of the Urban Waste Water Treatment Directive (UWWTD). Several EU Member States have yet to satisfy the requirements of the directive. A European Commission report released in 2004 noted that several countries had failed to designate sensitive areas and were behind schedule in establishing the capacity of sewage treatment as required by the directive deadlines in 1998 and 2000. As the next deadline is approaching at the end of 2005, for extending sewage treatment to urban areas with more than 2000 inhabitants, the EEA has acknowledged the need to improve our understanding of the inherent implementation problem. This pilot study examines the water quality situation and objectives of 6 Member States of the EU, including, Denmark, France, The Netherlands, Spain, Estonia and Poland, with a comparative analysis and conclusions.

This book presents a conceptual and practical tool for those involved directly or indirectly in the planning and management of basic provision of water supply, wastewater and stormwater services in metropolitan regions by offering insights into governance paradigms and institutional arrangements for urban wastewater reuse in agriculture from Australia and India. Instead of focusing on the technical aspects of designing and building infrastructure, it provides a better understanding of the institutional and governance challenges of managing urban wastewater, particularly for reuse in agriculture. As water supplies fall and water stress increases in many areas, the potential of wastewater as a resource is being widely recognized. Today, wastewater (re)use has become an attractive option for conserving and expanding available water supplies. While wastewater (re)use can have many applications, its use in agriculture is the most established, and the one with the longest tradition. Given the growing competition for freshwater from industry and cities, without doubt there is going to be a rapid increase in the global use of treated wastewater, making improved wastewater use in agriculture an emerging priority. Even though it is a vast resource if we reclaim it properly, often most wastewater is wasted. Therefore, in order to realize the full potential of this resource, decision support in policy design and implementation (Institutions and Governance) is key. Institutions and governance frameworks need to provide for the rights of access, rights of ownership, rights to manage source and treated water and the obligations of final use of recycling operations.

More than 1 million hectares of urban land in India could be irrigated for crops if wastewater was made safe for use. Lack of systematic data collection by municipalities makes it difficult to accurately assess the wastewater generation or estimate the total amount of urban area under wastewater irrigation, so the potential of urban and peri-urban farming could be even greater. This study attempted to analyze the current status of wastewater generation, its uses and livelihood benefits especially in agriculture, based on national data and case studies from Ahmedabad, New Delhi, Hyderabad, Kanpur and Kolkata.

Pharmaceutical wastewater is now a major concern due to the improper legislation around the globe and the poor implementation of existing laws. This book covers the various aspects of pharmaceutical sources, treatment technologies, and the harmful effect on the natural environment. The book will also highlight the concept of the 3Rs (reduce, reuse and recycle) as applied to the treatment and resource recovery systems for pharmaceutical treatment. The different innovative technologies will deal with reducing the energy requirements, the physical space requirements and impacts of treatment plants . Some case studies are included in order to fully understand the practical aspects of the treatment and modelling.

From a river-basin perspective, wastewater irrigation is an important form of water and nutrient reuse; however, there are important water quality, environmental, and public health considerations. This report explores the advantages and risks of urban wastewater reuse for crop production in the water-short Guanajuato river-basin in west-central Mexico, and then by a selective literature review demonstrates how common this practice is worldwide. It also evaluates several alternative water-management scenarios through application of the Interactive River Aquifer Simulation (IRAS) model, developed by Cornell University and Resource Planning Associates.