xiv Contents
8.2.2.3 Disease Transmission by Protozoa
in Recreational Water Through
Non-fecal Material.................... .......................... 207
8.2.2.4 Disease Transmission by Fungi in Recreational
Water Through Non-fecal Material:
Trichophyton spp. and Epidermophyton
floccosum................................. ........................... 208
8.3 Disease Transmission Through Shellfish Growing in Fecally
Contaminated Water ........................................................................ 208
8.3.1 Description of Shellfish ..................................................... 208
8.3.2 Monitoring the Aquatic Environment
of Shellfish Growth ............................................................ 209
8.3.2.1 Procedure for Monitoring Shellfish Growing
Areas in the US................... ................................ 210
8.4 Recent Developments Regarding Knowledge of Pathogens
in Drinking Water ............................................................................ 211
References ................................................................................................... 213
9 Municipal Purification of Water .............................................................. 215
9.1 The Need for Water Purification ...................................................... 215
9.2 The Quality of the Raw Water to Be Purified .................................. 216
9.3 Processes for the Municipal Purification of Water .......................... 217
9.3.1 Pretreatments ..................................................................... 217
9.3.2 Storage and Sedimentation Without Coagulation .............. 218
9.3.3 Aeration ............................................................................. 218
9.3.4 Coagulation and Flocculation ............................................ 219
9.3.5 Sedimentation .................................................................... 220
9.3.6 Filtration ............................................................................ 220
9.3.7 Chlorination (and Other Methods of) Disinfection ........... 221
9.3.7.1 Reactions of Chlorine with Chemicals
Found in Water......................... ........................... 222
9.3.7.2 The Present Practice of Water Chlorination ....... 224
9.3.7.3 Mode of Action of Chlorine Disinfection ........... 225
9.3.7.4 Factors Affecting the Efficacy of Disinfection
in Water by Chlorine (and the other Halogens) .. 225
9.3.7.5 Tests for Chlorine in Water ................................. 226
9.3.7.6 Alternative Methods of Disinfection Besides
Chlorine and Other Halogens ............................. 227
9.3.7.7 Ozone .................................................................. 227
9.3.8 Ultraviolet Light ................................................................ 229
9.3.8.1 Mode of Action and Use of UV .......................... 229
9.3.9 Iron and Manganese Control ............................................. 229
9.3.10 Softening of Water ............................................................. 230
9.3.11 Fluoridation ........................................................................ 230
9.3.12 Algae Control (and Control of Taste and Odors) ............... 231
9.3.12.1 Methods for the Control of Algae and Taste
and Odor............................................ ................ 231
9.3.13 Color and Turbidity Removal ............................................ 231