[...]... main types of suspended particles found in natural waters are as follows: • Inorganic • Organic, including macromolecules • Living and dead organisms Inorganic particles result mainly from natural weathering processes and include clays, such as kaolinite and montmorillonite; oxides, including various iron oxides; and silica, calcite, and many other minerals Particles in water 2 Organic material mainly... Microorganisms such as viruses and bacteria may be pathogenic (disease-causing) and so the water would be hazardous to human health Some pathogens may attach to other particles, such as clays, and this could “shield” them from disinfectants used in water treatment processes For various reasons, particles are undesirable in drinking water, and the main aim of most common water treatment processes is particle... is widely used Since the early days of colloid science, colloids in water have been divided into two distinct groups—hydrophilic and hydrophobic ( water loving” and water hating”) For nonaqueous colloids, the corresponding terms are lyophilic and lyophobic (“liquid-loving” and “liquid-hating”) We are only concerned here with aqueous colloids Hydrophilic colloids are essentially water- soluble macromolecules,... describing the fate of particles in the aquatic environment and in water and wastewater treatment plants Particles in water 20 2.3 Particle transport Particles in water may be transported in various ways, the most significant of which are as follows: • Convection • Diffusion • Sedimentation Convection is simply the movement of the particles as a result of flow, whereas diffusion and sedimentation cause particles. .. liquid in which they were suspended In fact, the theoretical treatment of this problem by Einstein and Smoluchowski and the agreement with experimental observations provided the first definitive proof of the long-conjectured existence of atoms and molecules The kinetic energy of water molecules means that they are in continuous chaotic motion, and particles suspended in water are constantly being bombarded... organisms in natural waters, and, in order of increasing size, they are classified as viruses (although these are not strictly cells), bacteria, algae (including diatoms), and protozoa Many of these may exist in water either as single cells or as much larger colonies Some examples of particles in natural waters are shown as micrographs in Figure 1.1 It is clear from this figure that aquatic particles. .. processes, but the basic principles apply to solid-liquid separation in a wide range of industries, including biotechnology, mineral processing, papermaking, and others Further reading Tadros, Th.F and Gregory, J., (Eds.), Colloids in the Aquatic Environment, Elsevier Applied Science, London (Special issue of Colloids and Surfaces A 73, 1993.) Wotton, R.S The Biology of Particles in Aquatic Systems, CRC... States), Karlsruhe (Germany), and Perth (Australia) Professor Gregory has about 40 years of experience in teaching and research in the areas of water pollution and water treatment His research work has f ocused mainly on physicochemical treatment processes, especially flocculation and filtration, and he has authored more than 100 publications in these and related areas He is internationally known for his... fraction of particles with In (size) in the range In x−ln x+d(ln x) It follows that when xf(x) is plotted against In x, the familiar bell-shaped gaussian curve is obtained, as in Figure 2.4 However, when f(x) is plotted against x, a distinct positive skew is apparent, especially for fairly high values of the logarithmic standard deviation (In fact, the distribution in Figure 2.1 is log-normal) The log-normal... flocculants, colloidal interactions, and monitoring techniques He introduced the well-known “electrostatic patch” model for flocculation by polyelectrolytes in 1973 During the 1980s, he was involved in the development of a simple monitoring technique for particles and aggregates in flowing suspensions, which has been commercialized and is widely used around the world He has been invited to lecture on . class="bi x0 y0 w0 h0" alt="" Particles in Water Properties and Processes Particles in Water Properties and Processes John Gregory University College London England Taylor & Francis. 0-2 0 3-6 214 8-4 (OEB Format) International Standard Book Number-10: 1-5 871 6-0 8 5-4 (Print Edition) (Hardcover) International Standard Book Number-13: 97 8-1 -5 871 6-0 8 5-1 (Print Edition) (Hardcover) Library. trademarks, and are used only for identification and explanation without intent to infringe. Library of Congress Cataloging -in- Publication Data Gregory, J. (John), 1938– Particles in water: properties