The goal of this project was to understand the formation and decay of selected DBPs in full-scale distribution systems focusing on the four THMs and the nine HAAs, as well as individual THM and HAA species. Because of its critical nature, NDMA was also included. The project objectives were: evaluate the critical factors that affect THM and HAA behavior in distribution systems; determine the fate and behavior of NDMA in distribution systems; evaluate the effect of pipe material and diameter on the fate of DBPs in distribution systems; examine the effect of storage reservoirs / tanks and booster chlorination stations on THM, HAA and NDMA concentrations; evaluate the changes in DBP concentrations and speciation when a system seasonally switches from chloramines to free chlorine to limit potential nitrification episodes....

There are two groups of specialists involved in the development and application of water quality models, each of which have a different perspective on the use of models: Academics and scientists - chemistry specialists and microbiologists who develop the models. Practitioners - modelers and distribution engineers who use them to solve problems. There are limitations and constraints in the characterization of the underlying processes and the practical application of models to distribution networks, which require further research. The objectives of the research were to characterize the current state of predictive distribution system water quality models and to identify critical research needs for their improvement. The project reviewed both the development and application of models. The report is intended to both steer future research and to act as a general reference on water quality modeling. The report combines a literature review with the practical experience of the project team. The content of a draft report was discussed at an international workshop attended by academics, engineers, scientists, and hydraulic modelers with the objective of agreeing on specific research needs necessary to improve predictive modeling for water quality in distribution systems. The conclusions of the report are derived from the workshop and form the basis of 11 specific research briefs that have been submitted to AwwaRF for consideration of funding. Researchers often focus on modeling the individual processes that control water quality rather than fully modeling water quality throughout distribution systems. For these "process models" to be applied to real distribution networks, they need to be extended to take in account the physical characteristics of the system?the special and temporal variations in flow, velocity and water age, and the effects of mixing water that has traveled along different flow paths.

Developing an improved understanding of emerging flood risk management and urban water management was the goal set for research presented at the 6th International Conference on Flood and Urban Water Management, held in A Coruña, Spain. The published papers look to solve various challenges in this field by drawing on the expertise of numerous disciplines and considering a range of responses. Flooding is a global phenomenon that claims numerous lives worldwide each year. When flooding occurs in urban areas, it can cause substantial damage to property as well as threaten human life. In addition, many more people must endure the homelessness, upset and disruption that are left in the wake of floods. The increased frequency of flooding in the last few years, coupled with climate change predictions and urban development, suggest that these impacts are set to worsen in the future. How we respond and importantly, adapt to these challenges is key to developing our long-term resilience at the property, community and city scale. Apart from the physical damage to buildings, contents and loss of life, which are the most obvious, impacts of floods upon households, other more indirect losses are often overlooked. These indirect and intangible impacts are generally associated with disruption to normal life as well as long-term health issues including community displacements and stress-related illnesses. Flooding represents a major barrier to the alleviation of poverty in many parts of the developing world, where vulnerable communities are often exposed to sudden and life-threatening events. As our cities continue to expand, their urban infrastructures need to be re-evaluated and adapted to new requirements related to the increase in population and the growing areas under urbanization. The papers contained in this book consider these problems and deals with two main urban water topics: water supply systems and urban drainage.

Provides guidelines for developing a water quality monitoring program specific to the distribution system of a water utility. The report identifies monitoring objectives, addresses common program design issues, and develops protocols for monitoring programs. Topics include nitrification, booster chl

The report of multi-disciplinary team of engineers and practitioners from a research project commissioned by the Association to create a resource to help water utilities operate and maintain water distributions systems to prevent water quality from deteriorating. They look at prevention programs, qu

During the past decade many countries in the world have experienced droughts, with severe impacts on water urban supply systems. Because droughts are natural phenomena, water utilities must design and implement drought management plans. This topic was selected for the International Course on Drought Management Planning in Water Supply Systems, which took place in Valencia, Spain, on 9-12 December 1997, and was hosted by the Universidad Internacional Menéndez y Pelayo (UIMP). The contributions in this book have been carefully selected and presented in four sections: Introduction Water Supply Systems Modernization Drought Management in an Urban Context Practical Cases (Israel, USA, Italy, Spain) To achieve a well-balanced approach, authors were invited from academia as well as from consultancies and water utilities, and have wide experience in the subject. The book is mainly aimed at water supply engineers, working in utilities and consultancies.

Maintaining chlorine and chloramine residual is a key factor that determines potability of distributed water. Decay of these disinfectants is affected by various water quality and infrastructure related factors. Understanding the decay of residuals in the distribution system is critical with respect to safe delivery of drinking water and in developing water quality models that can be used by utilities for the operation of potable water delivery systems. In order to comply with microbial and disinfection byproduct (M/DBP) regulations, water suppliers are continually investing in treatment processes for achieving greater levels of inactivation and DBP precursor removal. As a result of these changes in water quality, maintaining a disinfectant residual in the distribution system can be challenging Bench-scale testing has been used to determine the effect of advanced treatment (enhanced coagulation, granular activated carbon adsorption, ozonation, biofiltration, and ultraviolet irradiation) on chlorine and chloramine decay. Additional studies examine the effects of disinfectant dose, temperature, pH, blending, and rechlorination. The effects of water quality on pipe-wall demand were evaluated using the distribution system simulator at the U.S. Environmental Protection Agency's Test and Evaluation Center. Several models are developed regarding disinfectant decay, making it easier to predict chlorine demand after changes in treatment. The multi-species water quality analysis and network path analysis extensions to EPANET will make the modeling package more robust and will allow utilities to predict chlorine residual at any point in their distribution system with greater confidence.