Basic Environmental Technology Water Supply Waste Management and
Basic Environmental Technology Water Supply, Waste Management, and Pollution Control SIXTH EDITION CHAPTER 6 Drinking Water Purification Basic Environmental Technology, Sixth Edition Jerry A. Nathanson | Richard A. Schneider Copyright © 2015 by Pearson Education, Inc. All Rights Reserved
FIGURE 6 -1 A flow diagram of a typical surface water treatment plant. Screens keep fish and debris out of the plant; low-pressure pumps lift the water to the flash-mix tank; coagulation, sedimentation, and filtration remove turbidity and clarify the water; disinfection destroys pathogenic organisms; high-pressure pumps deliver potable water to the consumers. Basic Environmental Technology, Sixth Edition Jerry A. Nathanson | Richard A. Schneider Copyright © 2015 by Pearson Education, Inc. All Rights Reserved
TABLE 6 -1 Selected Primary Standard MCLs and MCLGs for Organic Chemicals Basic Environmental Technology, Sixth Edition Jerry A. Nathanson | Richard A. Schneider Copyright © 2015 by Pearson Education, Inc. All Rights Reserved
TABLE 6 -2 Selected Primary Standard MCLs for Inorganic Chemicals Basic Environmental Technology, Sixth Edition Jerry A. Nathanson | Richard A. Schneider Copyright © 2015 by Pearson Education, Inc. All Rights Reserved
TABLE 6 -3 National Secondary Drinking Water Standards Basic Environmental Technology, Sixth Edition Jerry A. Nathanson | Richard A. Schneider Copyright © 2015 by Pearson Education, Inc. All Rights Reserved
FIGURE 6 -2 A typical MCL violation notice that would appear in local newspapers. (Reprinted from Safe Drinking Water Act Self-Study Handbook, by permission. Copyright © 1978, The American Water Works Association. ) Basic Environmental Technology, Sixth Edition Jerry A. Nathanson | Richard A. Schneider Copyright © 2015 by Pearson Education, Inc. All Rights Reserved
FIGURE 6 -3 Schematic view of the sedimentation process. Basic Environmental Technology, Sixth Edition Jerry A. Nathanson | Richard A. Schneider Copyright © 2015 by Pearson Education, Inc. All Rights Reserved
FIGURE 6 -4 Simplified section view of a rectangular sedimentation tank. A slowly moving endless-chain scraper mechanism pushes sludge into a hopper for removal. Basic Environmental Technology, Sixth Edition Jerry A. Nathanson | Richard A. Schneider Copyright © 2015 by Pearson Education, Inc. All Rights Reserved
FIGURE 6 -5 In a circular sedimentation tank, the influent enters at the center of the tank and clarified water is skimmed from the surface as it flows over the effluent weir situated around the tank periphery. Basic Environmental Technology, Sixth Edition Jerry A. Nathanson | Richard A. Schneider Copyright © 2015 by Pearson Education, Inc. All Rights Reserved
FIGURE 6 -6 The shallow tank has a lower overflow rate than tank. Basic Environmental Technology, Sixth Edition Jerry A. Nathanson | Richard A. Schneider Copyright © 2015 by Pearson Education, Inc. All Rights Reserved
FIGURE 6 -7 A series of inclined tube settlers increases the effective surface area of a settling tank. Settleable solids are quickly entrapped in the downward-flowing sludge in each tube, whereas the clarified water flows upward. Basic Environmental Technology, Sixth Edition Jerry A. Nathanson | Richard A. Schneider Copyright © 2015 by Pearson Education, Inc. All Rights Reserved
FIGURE 6 -8 Plate settlers can be installed in new or in existing sedimentation tanks to improve suspended solids removal efficiency. (Courtesy of Jim Myers & Sons, Inc. Charlotte, NC. ) Basic Environmental Technology, Sixth Edition Jerry A. Nathanson | Richard A. Schneider Copyright © 2015 by Pearson Education, Inc. All Rights Reserved
FIGURE 6 -9 A stirring apparatus for the jar test, which is used to determine optimum coagulant dosage. (Courtesy of Phipps & Bird Inc. ) Basic Environmental Technology, Sixth Edition Jerry A. Nathanson | Richard A. Schneider Copyright © 2015 by Pearson Education, Inc. All Rights Reserved
FIGURE 6 -10 Schematic diagram of the filtration process. Basic Environmental Technology, Sixth Edition Jerry A. Nathanson | Richard A. Schneider Copyright © 2015 by Pearson Education, Inc. All Rights Reserved
FIGURE 6 -11 Schematic diagram of the backwash or cleaning cycle of a rapid filter. Basic Environmental Technology, Sixth Edition Jerry A. Nathanson | Richard A. Schneider Copyright © 2015 by Pearson Education, Inc. All Rights Reserved
FIGURE 6 -12 a Typical gradation of a rapid sand filter bed. Solids removal occurs primarily by straining action at the top of the sand bed. Basic Environmental Technology, Sixth Edition Jerry A. Nathanson | Richard A. Schneider Copyright © 2015 by Pearson Education, Inc. All Rights Reserved
FIGURE 6 -12 b Typical coarse-to-fine gradation in a mixed-media filter. It is preferable to the sand because it provides in-depth filtration. Basic Environmental Technology, Sixth Edition Jerry A. Nathanson | Richard A. Schneider Copyright © 2015 by Pearson Education, Inc. All Rights Reserved
FIGURE 6 -13 Schematic diagrams of a rapid filter in the (a) filtering cycle and (b) backwash cycle of operation. Valves A, B, C, D, and E control the flow. Valve E is opened briefly when filtering starts. Basic Environmental Technology, Sixth Edition Jerry A. Nathanson | Richard A. Schneider Copyright © 2015 by Pearson Education, Inc. All Rights Reserved
FIGURE 6 -14 Breakpoint chlorination curve. Basic Environmental Technology, Sixth Edition Jerry A. Nathanson | Richard A. Schneider Copyright © 2015 by Pearson Education, Inc. All Rights Reserved
FIGURE 6 -15 Typical hypochlorinator installation. (Courtesy of J. L. Wingert Co. ) Basic Environmental Technology, Sixth Edition Jerry A. Nathanson | Richard A. Schneider Copyright © 2015 by Pearson Education, Inc. All Rights Reserved
FIGURE 6 -16 (a) An ion-exchange column used for water softening; (b) the column may be regenerated and used again after washing with a strong salt solution. Basic Environmental Technology, Sixth Edition Jerry A. Nathanson | Richard A. Schneider Copyright © 2015 by Pearson Education, Inc. All Rights Reserved
FIGURE 6 -17 An assembly of spiral-wound RO tubes. (Henry. Ho/Shutterstock. ) Basic Environmental Technology, Sixth Edition Jerry A. Nathanson | Richard A. Schneider Copyright © 2015 by Pearson Education, Inc. All Rights Reserved
- Slides: 22