This collection contains 49 papers presented at an Engineering Foundation Conference, held in Snowmass Village, Colorado, August 19-24, 2001.

This comprehensive book provides an up-to-date and international approach that addresses the Motivations, Technologies and Assessment of the Elimination and Recovery of Phosphorus from Wastewater. This book is part of the Integrated Environmental Technology Series.

Brian D. Clark PADC Environmental Impact Assessment and Planning Unit Project Director Events throughout the world substantiate the view that planning and decision-making systems need a better integration of environ mental, economic and social considerations. Many organizations are showing considerable interest in Environmental Impact Assessment (EIA) and its role in project planning and policy evaluation and as an aid to decision-making. Consequently, it was decided to hold a NATO Advanced Study Institute on EIA for the following reasons. First there is evidence of uncertainty, particularly amongst many scientists and decision-makers, as to the nature, scope and object ives of EIA. Secondly, there is much confusion over the objectives and utility of certain EIA methods. Third, there appears to be a gulf developing between decision-makers and what they require from EIA, and the ability of the scientist to provide information which is scientifically rigorous. Finally, there appears to be little concern as to the relationship between "impact prediction" and the actual consequences ofa development activity, suggesting that if EIA is not to become both politically and scientifically disreput able greater emphasis should be placed on prediction, monitoring and post-audit studies. As will be seen from the contents of this volume the ASI attempted to address all of the above topics and indeed many more. It was perhaps inevitable that the ASI raised more questions than were answered but this is indicative of the vigorous debate that is now taking place about the role and utility of EIA.

Slow sand filtration is typically cited as being the first "engineered" process in drinking-water treatment. Proven modifications to the conventional slow sand filtration process, the awareness of induced biological activity in riverbank filtration systems, and the growth of oxidant-induced biological removals in more rapid-rate filters (e.g. biological activated carbon) demonstrate the renaissance of biofiltration as a treatment process that remains viable for both small, rural communities and major cities. Biofiltration is expected to become even more common in the future as efforts intensify to decrease the presence of disease-causing microorganisms and disinfection by-products in drinking water, to minimize microbial regrowth potential in distribution systems, and where operator skill levels are emphasized. Recent Progress in Slow Sand and Alternative Biofiltration Processes provides a state-of-the-art assessment on a variety of biofiltration systems from studies conducted around the world. The authors collectively represent a perspective from 23 countries and include academics, biofiltration system users, designers, and manufacturers. It provides an up-to-date perspective on the physical, chemical, biological, and operational factors affecting the performance of slow sand filtration (SSF), riverbank filtration (RBF), soil-aquifer treatment (SAT), and biological activated carbon (BAC) processes. The main themes are: comparable overviews of biofiltration systems; slow sand filtration process behavior, treatment performance and process developments; and alternative biofiltration process behaviors, treatment performances, and process developments.