ABSTRACT
Methods for Maintaining Winter Highway Safety ........................................................ 163 Antiskid Materials .......................................................................................................... 163 Chemical De-icers .......................................................................................................... 164 De-icer Components and Their Potential Environmental Effects ................................. 165
6.5 Drinking Water Treatment .................................................................................................... 166 Water Sources................................................................................................................. 167 Water Treatment ............................................................................................................. 167 Basic Drinking Water Treatment ................................................................................... 168 Disinfection Byproducts and Disinfection Residuals.................................................... 170 Strategies for Controlling Disinfection Byproducts ...................................................... 170 Chlorine Disinfection Treatment.................................................................................... 171 Drawbacks to Use of Chlorine: Disinfection Byproducts (DBPs) ............................... 174 Chloramines.................................................................................................................... 176 Chlorine Dioxide Disinfection Treatment ..................................................................... 176 Ozone Disinfection Treatment ....................................................................................... 177 Potassium Permanganate................................................................................................ 178 Peroxone (Ozone + Hydrogen Peroxide) ...................................................................... 179 Ultraviolet (UV) Disinfection Treatment....................................................................... 179 Membrane Filtration Water Treatment........................................................................... 180
6.6 Ion Exchange ........................................................................................................................ 182 Why Do Solids in Nature Carry a Surface Charge? ..................................................... 183 Cation and Anion Exchange Capacity (CEC and AEC) ............................................... 183 Exchangeable Bases: Percent Base Saturation .............................................................. 184 CEC in Clays and Organic Matter................................................................................. 186 Rates of Cation Exchange.............................................................................................. 186
6.7 Indicators of Fecal Contamination: Coliform and Streptococci Bacteria ........................... 187 Background..................................................................................................................... 187 Total Coliforms............................................................................................................... 187 Fecal Coliforms .............................................................................................................. 188
E. coli
............................................................................................................................. 188 Fecal Streptococci .......................................................................................................... 188 Enterococci ..................................................................................................................... 188
6.8 Municipal Wastewater Reuse: The Movement and Fate of Microbial Pathogens...............189 Pathogens in Treated Wastewater..................................................................................189 Transport and Inactivation of Viruses in Soils and Groundwater ................................190
6.9 Odors of Biological Origin in Water ....................................................................................191 Environmental Chemistry of Hydrogen Sulfide ...........................................................191 Chemical Control of Odors...........................................................................................192
