IntroductionpH value or range is of immense importance for any chemical reaction. A chemical shall be highlyeffective at a particular pH. Chemical coagulation, disinfection, water softening and corrosion control aregoverned by pH adjustment. In anaerobic treatment below pH 5.0, acids accumulate and the process is severelyaffected. Shifting of pH beyond 5 to 10 upsets the aerobic treatment of the wastewater. Dewatering of sludges,oxidation of cyanides and reduction of hexavalent chromium need a favorable pH range. High values of pHhasten the scale formation and reduce germicidal potential of chlorine.