Guest▼Comment In honor of Charles R. O’Melia: Researcher, scholar, engineer, and educator
352A ■ ENVIRONMENTAL SCIENCE & TECHNOLOGY / SEPTEMBER 1, 2005
successfully applied to the description of particle transport in subsurface porous media and the colloid-facilitated transport of contaminants. O’Melia’s advances to our basic understanding of the mechanisms controlling particle deposition to solid surfaces have been very useful for depicting the deposition and transport of microbes in aquatic systems. Papers in this special tribute address bacterial deposition/adhesion (Morrow et al. and Walker et al.) and transport of viruses and Cryptosporidium oocysts in porous media (Abudalo et al.). As with particle deposition/filtration, the attachment of microbes to solid surfaces is dramatically affected by the charge characteristics of the microbes and solid surfaces. O’Melia has also been an influential contributor to our understanding of the significant role of natural organic matter (NOM) in engineered and natural aquatic systems. A group of papers—Lin et al., Pommerenk and Schafran, Duval et al., Weber et al., and Holbrook et al.— describe the influence of NOM on precipitation kinetics and particle removal, the electrokinetic characterization of NOM macromolecules, the formation of disinfection byproducts by fulvic components of NOM, and the impact of wastewater-derived organic macromolecules on the organic composition of receiving surface waters. Subsequent papers—Wang et al., Xu and Chellam, Lee et al., and Olufemi Abitoye et al.—explore particle/microbial deposition onto membrane surfaces, membrane fouling, and membrane performance. O’Melia and his students have more recently been engaged in membrane research, and the general framework developed by the group to describe particle deposition and aggregation has proved useful in explaining the accumulation of colloids and microbial particles at the membrane–water interface. Papers by Park and Dempsey, Boccelli et al., Cumbal and SenGupta, Ahn et al., and Nguyen et al. conclude PECK STUDIOS
I
n this special issue of ES&T, we pay tribute to Charles R. O’Melia—the Abel Wolman Professor of Environmental Engineering at Johns Hopkins University—for his many contributions to research and education in environmental engineering and science. O’Melia’s groundbreaking research on filtration, coagulation, and the behavior of colloidal particles in aquatic systems is the cornerstone of our current knowledge of these areas. His work has inspired scientists and engineers worldwide and has made a profound impact on the design and operation of water treatment plants. The 24 papers in this special tribute—contributed by a diverse group of scientists, colleagues, and former students— cover several key areas that O’Melia has helped to define and advance during his remarkable academic career. The first three papers—Lawler and Nason, Brant et al., and Taboada-Serrano et al.—deal with coagulation in water treatment and particle/surface characterization, which are the subjects of many of O’Melia’s early contributions. The first paper addresses the role of hydrodynamic and surface interactions and their implications for coagulation and the modeling of water treatment plant performance. The subsequent two papers describe the characterization of charge and charge heterogeneity of particles and solid surfaces; charge characteristics of particles and surfaces have a profound effect on particle coagulation and deposition processes. The next set of papers—Kulkarni et al., Salerno et al., Grolimund and Borkovec, and Ren and Packman—examine the processes of particle deposition and colloidfacilitated transport of contaminants. O’Melia has made seminal contributions in the area of particle deposition and transport in porous media. He was among the first to isolate the effects of physical and chemical interactions on particle deposition and filtration. The filtration theories developed by O’Melia have been widely and
© 2005 American Chemical Society
the tribute issue. These articles investigate reactions and sorption phenomena at the solid–water interface, examining surfaces comprised of metal oxides and organic solids and chemical species that include inorganic as well as organic contaminants. In his early work on coagulation, O’Melia recognized the importance of chemical reactions at the particle–water interface and the marked influence of such surface reactions on colloidal stability and coagulation. We thank the contributors to this special tribute for their prompt submission and revision of articles and the reviewers for their expert and timely responses. We are most grateful to Associate Editor Janet Hering and her editorial assistant, Sheila Miyazaki, for their able guid-
ance and help in processing manuscripts. We also acknowledge the special editors—Jim Edzwald and Joe Ryan—for their dedication and care in handling the reviews of several papers. It is our hope that this collection of papers will enable the reader to appreciate the central importance of aquatic particles and interfaces in environmental processes in natural and engineered systems and will inspire and aid further research in this area. William P. Ball Johns Hopkins University Menachem Elimelech Yale University John E. Tobiason
Guest editors for the Charles R. O’Melia tribute issue Five editors selected manuscripts for consideration and managed the review process for the papers that appear in the tribute section of this issue of ES&T.
Menachem Elimelech Yale University Tribute Issue Editor
William P. Ball Johns Hopkins University
James Edzwald University of Massachusetts, Amherst
Joseph Ryan University of Colorado, Boulder
John E. Tobiason University of Massachusetts, Amherst
SEP TEMBER 1, 2005 / ENVIRONMENTAL SCIENCE & TECHNOLOGY ■ 353A
