文档介绍：9
Physical Water
and Wastewater
Treatment Processes
Screens
Bar Screens • Coarse Screens • Comminutors and In-Line
Grinders • Fine Screens • Microscreens • Orifice Walls
Chemical Reactors
Hydraulic Retention Time • Reaction Order • Effect of Tank
Configuration on Removal Efficiency
Mixers and Mixing
Mixing Devices • Power Dissipation • Blending • Particle
Suspension
Rapid Mixing and ulation
Rapid Mixing • ulation
Sedimentation
Kinds of Sedimentation • Kinds of Settling Tanks • Floc
Properties • Free Settling • Design of Rectangular Clarifiers •
Design of Circular Tanks • Design of High-Rate, Tube, or Tray
Clarifiers • Clarifier Inlets • Outlets • Sludge Zone • Freeboard •
Hindered Settling • Thickener Design
Filtration
Granular Media Filters • Water Treatment • Wastewater
Treatment
Activated Carbon
Preparation and Regeneration • Characteristics • Uses •
Robert M. Sykes Equilibria • ics • Empirical Column Tests • Application
The Ohio State University Aeration and Gas Exchange
Equilibria and ics of Unreactive Gases • Oxygen Transfer •
Harold W. Walker Absorption of Reactive Gases • Air Stripping of anic
The Ohio State University Substances
Screens
The important kinds of screening devices are bar screens, coarse screens, comminutors and in-line
grinders, fine screens, and microscreens (Pankratz, 1988).
Bar Screens
Bar screens may be subdivided into (1) trash racks, (2) mechanically cleaned bar screens, and (3) manually
cleaned bar screens.
© 2003 by CRC Press LLC
9-2 The Civil Engineering Handbook, Second Edition
Trash Racks
Trash racks are frequently installed in surface water treatment plant intakes to protect course screens
from impacts by large debris and to prevent large debris from bined/storm water sewerage
systems. Typical openings are 1 to 4 in. The bars are made of steel, and their shape and size depend on
the expected structural loads, which are both s