Evaluating the Use of Ozone For Disinfection of Drinking Water, Case Study: Tehran Pars Water Treatment Plant Iran

During recent years , surface water resourcessupplying tehran's potable water - karaj, lar andjajr ood rivers - are contaminated with differen tmicroorgani sms due to popul at ion growt h.additionally, the amount of organic materi alsgeneratin g odor, taste and color in the surfacewater has increased sharp ly. by considering thetrih alometh ane (thm) production potential ofdissolved chlorine in reaction with innocuoushumic substa nces, future use of chlorine as adisinfectant in tehran's drinking wate r is cloudedin uncert ainty . accordingly, the use of ozone asanother alternative was taken in to cons idera tionfor disinfect ion of drinkin g water in this megacity. in order to evaluate advantages anddisadvantages of water ozonat ion a pilot with agenerat ing cal?acity of 4 gr ozone per hour wasdesigned. this study was performed betweenapril and september 2005 and tehran pars wate rtreatment plant in the northeas t of tehran waschosen for the case study. bacteria removal wasconsidered to be at highest leve l in all monthl ysamples. different ozone contact times anddosages were tested in the deactivation ofnematodes and the result s showe d the perfectremoval in spec ified periods. although the initia linvestment for const ruction and implement ation ofthe required apparatuses is relative ly high, sincethe raw matenal for ozone generation is air, theuse of ozone is fina ncia lly justifiable duri ng thepredi cted time ofoperation.moreover, the transferand storage of ozone is much easier in compariso nwith chlorine which is curre ntly in use. unlikechlorine, the use of ozone as a disinfectant doesnot have the potential ofthms genera tion. on theother hand , ozone must be generated on site and isinstable in water. therefore, a continuous andprecise monitoring and mai ntenance process mustbe take n in to considera tion. furthermore, due tohigh corrosive potent ial of ozone, specia l res istantmateri als must be used in the applied instruments.