DISINFECTIONHISTORYBroad Street PumpChlorinationSlide 5TheorySlide 7ChlorinatorsSlide 9Chlorine Contact TankOzonationChlorine DioxideUltraviolet (UV) LightADSORPTIONSlide 15Particle Size vs. Treatment AlternativesSlide 17Membrane TreatmentReverse OsmosisSlide 20Slide 21DISINFECTIONDISINFECTIONCE326 PRINCIPLES OF ENVIRONMENTAL ENGINEERINGCE326 PRINCIPLES OF ENVIRONMENTAL ENGINEERINGIowa State UniversityIowa State UniversityDepartment of Civil, Construction, and Environmental Engineering Department of Civil, Construction, and Environmental Engineering Tim Ellis, Associate ProfessorTim Ellis, Associate ProfessorMarch 14, 2008March 14, 2008HISTORYHISTORYJ_____ S____ and the Broad Street pump in 1854J_____ S____ and the Broad Street pump in 1854he was able to show that 59 of the 77 c________ he was able to show that 59 of the 77 c________ victims used the pump on Broad Streetvictims used the pump on Broad StreetThere was a w___________ in the vicinity where There was a w___________ in the vicinity where cholera was endemic but nobody at this cholera was endemic but nobody at this workhouse got cholera. workhouse got cholera. This particular workhouse had its own w_____. This particular workhouse had its own w_____. The cause of contamination turned out to be the The cause of contamination turned out to be the d________ of an infected person that was within d________ of an infected person that was within three feet of the well.three feet of the well.Broad Broad Street Street PumpPumpChlorinationChlorinationDisinfection of water supplies by c____________ Disinfection of water supplies by c____________ began in Chicago and New Jersey in 1908, began in Chicago and New Jersey in 1908, within 2 years chlorination of w_____ s________ within 2 years chlorination of w_____ s________ was practiced in N.Y., Montreal, Milwaukee, was practiced in N.Y., Montreal, Milwaukee, Cleveland, Nashville, Baltimore, and Cincinnati. Cleveland, Nashville, Baltimore, and Cincinnati. By 1918, over 1000 c_____ treating more than __ By 1918, over 1000 c_____ treating more than __ bgd were chlorinating their water supplies.bgd were chlorinating their water supplies.By 1923 the typhoid death rate had dropped more By 1923 the typhoid death rate had dropped more than 90%than 90%By the beginning of WWII, typhoid, cholera, By the beginning of WWII, typhoid, cholera, dysentery were practically eliminated in U.S.dysentery were practically eliminated in U.S.TheoryTheoryChick’s Law: Chick’s Law: rate, k, is a function of concentration and time (i.e., CT) and type of organismrate, k, is a function of concentration and time (i.e., CT) and type of organismTypical disinfectants:Typical disinfectants:–Chlorine:Chlorine:ClCl22 + H + H22O → HOCl + ClO → HOCl + Cl--–ChloraminesChloraminesNHNH33 + HOCl → NH + HOCl → NH22Cl + HCl + H2200NHNH22Cl + HOCl → NHClCl + HOCl → NHCl22 + H + H2200NHClNHCl22 + HOCl → NCl + HOCl → NCl33 + H + H2200d Nd tk N Pellet dropperTablet feederChlorinatorsChlorinatorsGas – 2,000 poundCourtesy Smith Group Consulting, LLCChlorinatorsChlorinatorsChlorine Contact TankChlorine Contact Tankwww.wsd.dst.il.us/tour/imgbig/contact_tk_1.jpgOzonationOzonationstrong o_________, strong o_________, but no residualbut no residualno THM f_________ no THM f_________ but other (non-but other (non-chlorinated) DBPs chlorinated) DBPs possiblepossibleoften used as a often used as a p__________ p__________ disinfectantdisinfectantChlorine DioxideChlorine Dioxidestrong oxidant, but not strong oxidant, but not a powerful as o_____a powerful as o_____dose limited to 1.0 dose limited to 1.0 mg/L due to health mg/L due to health concerns of chlorite concerns of chlorite and c_______and c_______residual is not long residual is not long l_______l_______Ultraviolet (UV) LightUltraviolet (UV) Lightuses thin layer of water and uses thin layer of water and mercury vapor arc l______ mercury vapor arc l______ emitting UV in the range of 0.2 emitting UV in the range of 0.2 to 0.29 micronto 0.29 microndepth of light p_________ depth of light p_________ limited to 50 - 80 mmlimited to 50 - 80 mmpowerful, but no residualpowerful, but no residualADSORPTIONADSORPTIONtakes advantage of takes advantage of physical/chemical bond of physical/chemical bond of pollutant with adsorbent (typically pollutant with adsorbent (typically g_________ activated carbon or g_________ activated carbon or p_________ activated carbon)p_________ activated carbon)one ounce of GAC has a surface one ounce of GAC has a surface area of _____ acresarea of _____ acresgood process for removal of good process for removal of –THMsTHMs–DBPsDBPs–SOCsSOCs–VOCsVOCsADSORPTIONADSORPTIONPAC dose is typically _____ mg/L can be as PAC dose is typically _____ mg/L can be as high as _____mg/Lhigh as _____mg/LGAC can be used instead of a________ in GAC can be used instead of a________ in dual media filters, dual media filters, –called filter adsorbers called filter adsorbers –must replace GAC every ____ yearsmust replace GAC every ____ yearsseparate stage adsorption unit (contactor separate stage adsorption unit (contactor unit) unit) –GAC must be replaced or regenerated every __ GAC must be replaced or regenerated every __ to ___ monthsto ___ monthsParticle Size vs. Treatment AlternativesParticle Size vs. Treatment AlternativesMacromolecules Smaller ParticlesLargeSuspended ParticlesMF UF NF RODivalent saltsMonovalent saltsWaterMicro filtration (MF) - bacteria, algae, clay, large MW humic acids Ultra filtration (UF) - humic acids, viruses, proteinNanofiltration (NF) – viruses, divalent saltsReverse Osmosis (RO) – monovalent saltsMembrane TreatmentMembrane TreatmentReverse OsmosisReverse Osmosis4-stage Reverse Osmosis Unit with Tank and Faucet4-stage Reverse Osmosis Unit with Tank and