<p> I would like to mention some of the changes and additions that have been included in the third edition of Wastewater Microbiology. In general, every chapter of the book has been revised (up to July 2004) to include the latest developments in the field, and I will highlight only the major ones. </p> <p> A review of the most important molecular techniques has been added to Chapter 1, while the most recent methodology for measuring microbial biomass in environmental samples is described in Chapter 2. New developments in enhanced biological phosphorus removal (EBPR) are covered in Chapter 3. Chapter 4 covers new findings on old and emerging (e.g., Helicobacter pylori, Cyclospora, Microsporidia) microbial pathogens and parasites. Much progress has been made concerning the detection of Cryptosporidium and Giardia in environmental samples, including wastewater. The improved methodology is also covered in Chapter 4. As regards disinfection of water and wastewater, research efforts are now focusing on UV disinfection in industrialized countries and on the use of solar radiation in developing countries (Chapter 6). </p> <p> Armed with new molecular tools and microsensor /microelectrode technology, investigators are making progress in understanding the microbial ecology and the surface properties of activated sludge floes. The methodology used is similar to that used in biofilms. These advances will help us to better understand the flocculation process in activated sludge (Chapter 8). Concerning bulking and foaming in activated sludge plants, most of the recent studies have focused on the characterization and phylogeny of filamentous microorganisms (Chapter 9). </p> <p> In the last few years we have witnessed an increased interest in biofilm microbiology. Biofilms develop on biological and nonbiological surfaces and are ubiquitous in natural aquatic environments and engineered systems (e.g., fixed-film bioreactors). Their beneficial role in fixed-film bioreactors has been known for years (chapter 10). </p>

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