Flocculation in Natural and Engineered Environmental Systems (PDF)

Gary G.Leppard is an environmental biochemist and microbiologist who studies the roles of natural and engineered aquatic aggregates (flocs, biofilms) in the transport and fate of contaminants. In concert with these activities, he develops electronoptical means to analyze the colloidal structure of natural dispersing agents and the flocs of water treatment tanks. He joined the staff of the National Water Research Institute of Environment Canada at Burlington (ON) in 1975, as a research scientist. While also holding a professorship at McMaster University and membership in the Brockhouse Institute for Materials Research (Hamilton, ON), he is a Fellow of the International Union of Pure and Applied Chemistry and a Consulting Fellow of the World Innovation Foundation. In sequence, he was an invited scientist at the University of Paris (France), the University of Milan (Italy), Laval University (Quebec City), the National Research Council of Canada (Ottawa), the University of Geneva (Switzerland), the University of Vienna (Austria), and the Rudjer Boskovic Institute (Croatia). Dr. Leppard received degrees in several fields of biology and biological chemistry from the University of Saskatchewan (Saskatoon, SK) and from Yale University (New Haven, CT, United States). A Ph.D. in cell biology, with a specialization in electron-optical methods, was received from Yale in 1968. Research interests then extended into biogeochemistry, wastewater treatment, materials science, and the activities of natural microbial consortia. His interdisciplinary research has led to awards from the North Atlantic Treaty Organization, the Commission of the European Communities, and the RITE innovative technology organization in Japan, as well as a role on the editorial board of the Encyclopedia of Analytical Science. Current scientific interests focus on the control, by nanoscale phenomena, of macroscale effects in aquatic environments. These interests are coupled to the development of technology for commercial use, and include environmental projects for synchrotron laboratories.

Steven N. Liss is a professor of applied microbiology in the Department of Chemistry and Biology at Ryerson University and is the Associate Dean (Research, Development and Science Programs) for the Faculty of Engineering and Applied Science. Dr. Liss holds adjunct professorships at the University of Toronto in the Departments of Chemical Engineering and Applied Chemistry and Civil Engineering. Dr. Liss holds an under graduate degree in microbiology and immunology from the University of Western Ontario (1980) and graduate degrees in applied microbiology from the University of Saskatchewan (M.Sc, 1983; Ph.D., 1987). Dr. Liss currently leads research projects on the microbiology of wastewater treatment, waterwells, and environmental biotechnology. His research is supported by awards from the Natural Sciences and Engineering Research Council of Canada, the National Centres of Excellence, Ontario Centres of Excellence, Environment Canada, Canada Foundation for Innovation (CFI), and a wide range of industry partners. Specific research activities include microbial floc architecture in engineered and natural systems, microbialecology, water quality, filamentous microorganisms and bulking problems, bio fouling and microbial-based tools for studying, and monitoring biological treatment systems including DNA microarrays. His laboratory has developed expertise related to the physicochemical properties of microbial structures, their composition and structure, and the application of advanced optical microscopy in studying microbial structures and physiology. His research in waste water microbiology led to the Ryerson Distinguished Research Award in 1998. Dr. Liss has supervised 32 graduate students at the masters and Ph.D. levels. He is the author and co-author of over 100 peer-reviewed journal publications, book chapters, conference presentations and technical reports.

Timothy G. Milligan is a researcher with the Marine Environmental Sciences Division, Fisheries and Oceans Canada. As head of the Particle Dynamics Laboratory at the Bedford Institute of Oceanography he leads the group's research into the behavior of fine particulate material in aquatic environments. He received his B.Sc in geology and M.Sc in oceanography from Dalhousie University and has been involved with flocs for over 30 years. While his initial contact was in pulp mill effluent, it was the time spent with the late Dr. Kate Kranck, a pioneer in flocculation studies in the marine environment, that gave him his love of mud. Areas of interest include the mechanisms governing the loss of sediment from river plumes, the effect of flocculation on the transport and fate of contaminants, and environmental impacts of offshore oil and gas and aquaculture. Mr. Milligan has led research projects in a wide range of geographical areas, from the Amazon to the Canadian Arctic. While his work concentrates mainly on the marine environment, the fate of terrestrially derived sediments and associated contaminants has led him into the study of fluvial transport as well. Mr. Milligan has been involved in many international ventures, several of which have received funding from the U.S. Office of Naval Research. His work combines in situ techniques with process-based parameterization of the size distributions of the component grains in suspended and bottom sediment to better understand the fate of mud in both marine and fresh water systems. Over 80 peer-reviewed primary publications, book chapters and technical reports have been produced from this work.