Treatment of Swimming Pool Water with UV Followed by Ozone

Transcription

1 Downloaded from orbit.dtu.dk on: Dec 0, 017 Treatment of Swimming Pool Water with UV Followed by Ozone Cheema, Waqas Akram; Kaarsholm, Kamilla Marie Speht; Andersen, Henrik Rasmus Publication date: 016 Document Version Publisher's PDF, also known as Version of record Link back to DTU Orbit Citation (APA): Cheema, W. A., Kaarsholm, K. M. S., & Andersen, H. R. (016). Treatment of Swimming Pool Water with UV Followed by Ozone. Abstract from International Ozone Association Pan American Group, Las Vegas, United States. General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. Users may download and print one copy of any publication from the public portal for the purpose of private study or research. You may not further distribute the material or use it for any profit-making activity or commercial gain You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.

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3 Treatment of swimming pool water with UV followed by ozone W.A. Cheema, K.M.S. Hansen, H.R. Andersen International Ozone Association (PAG-IOA) Conference 8 31 August, 016 Las Vegas, Nevada

4 Swimming pool Filling water Equalisation tank Dissolved matters Pre-filter Coagulant Chlorine ph Sand filter Particles Sweat Urine Lotion Shampoo Make-up Hair Skin cells Bacteria and virus

5 Disinfection byproducts (DBPs) Chlorine + Dissolved matter Byproducts Trihalomethanes Combined chlorine Haloacetonitriles Haloacetic acids Trichloramine Potential health risk

6 Ozone in pools Oxidation of pollutants I. Direct reaction DOC + O 3 DOC selectively oxidized Fast consumption of ozone Decrease chlorine reactivity of pollutants Low ozone life time no reaction with bromide II. Radical reaction H O + O 3 O + HO DOC + HO DOC radical oxidized Slow consumption of ozone Ozone converts to hydroxyl radicals with time Radical attack of inactive carbon increased chlorine reactivity Long ozone life time oxidation of bromide to bromate

7 Systems: DIN (German standard) Equalization basin mg/l free chlorine ph flocculant Filtration Chlorine addition Nominal ozone addition 0.8 mg/l Residence time > 3 min Activated carbon /sand filter

8 Systems: Slip-stream (USA) DEL Ozone proprietary drawing

9 Lab-scale experiments O 3 /O mg O 3 /L O time (min) O 3 collection bottle

10 Chlorination of the ozonated samples Chlorine: 4 h at 5 C Chlorine residual Aim: 1-3 mg/l Trihalomethane by purge&trap GC/MS &

11 Repeated ozonation ozone lifetime C/C 0 (%) 50 Tap water 100 1st nd 75 3rd C/C 0 (%) Pool water 100 1st nd 75 3rd 4th time (min) Fast removal of 1 st ozone dose ozone reactive material nd and 3 rd no ozone reactive material time (min) Little difference no ozone reactive material in the water

12 Chlorine consumption.0 Tap water Pool water Cl -consumption (mg/l) I II II I. Direct oxidation by ozone II. Radical mechanism st nd 3rd 0 1st nd 3rd 4th 5th Ozone dose mg/l Different chlorine consumption for tap water and swimming pool water

13 Formation of total trihalomethane TTHM formation (µmol/l) Tap water I II 6 % 37 % 13 % 10 % II 6. % pool water 4.3 % 3.3 % 3.6 % DOC 4. % 4. % TTHM Incorporated Br I. Direct oxidation by ozone II. Radical mechanism st nd 3rd 0 1st nd 3rd 4th 5th Ozone dose mg/l Ozonation of tap water decreased THM Ozonation of pool water increased THM

14 Range finding for the effect of UV activation on chlorine reaction 10 Chlorine Consumption 0.5 TTHM Cl -consumption (mg/l) Concentration ( mmol/l) % 5% 5.5% 5.3% 5.% 1% 0 Control,Cl UV ½d,Cl UV 1d,Cl,Cl UV 4d,Cl UV 10d,Cl 0.0 Control,Cl UV ½d,Cl UV 1d,Cl,Cl UV 4d,Cl UV 10d,Cl

15 Ozone kinetics and chlorine consumption 100 kinetics 8 7 Chlorine consumption O 3 UV UV,O 3 C/C0 (%) Control, ppm O 3,ppm O 3 Cl consumption (mg/l) Time (min) 0 Control,Cl 1ppm O 3,Cl ppm O 3,Cl 4ppm O 3,Cl,Cl,1ppm O 3,Cl,ppm O 3,Cl,4ppm O 3,Cl,7ppm O 3,Cl,10ppm O 3,Cl

16 Dissolved organic carbon at different experimental treatment.5.0 TOC O 3 UV UV,O 3 TOC (mg/l) Control,Cl 1ppm O 3,Cl ppm O 3,Cl 4ppm O 3,Cl,Cl,1ppm O 3,Cl,ppm O 3,Cl,4ppm O 3,Cl,7ppm O 3,Cl,10ppm O 3,Cl

17 Trihalomethanes TTHM 0.40 O 3 UV UV,O % 5.8% 6.6% 7.4% TTHM (mmol/l) %.8%.6% 5.6%.1% 0.5% Control,Cl 1ppm O 3,Cl ppm O 3,Cl 4ppm O 3,Cl,Cl,1ppm O 3,Cl,ppm O 3,Cl,4ppm O 3,Cl,7ppm O 3,Cl,10ppm O 3,Cl

18 Trihalomethanes TTHM 0.40 O 3 UV UV,O % 5.8% 6.6% 7.4% TTHM (mmol/l) %.8%.6% 5.6%.1% 0.5% Control,Cl 1ppm O 3,Cl ppm O 3,Cl 4ppm O 3,Cl,Cl,1ppm O 3,Cl,ppm O 3,Cl,4ppm O 3,Cl,7ppm O 3,Cl,10ppm O 3,Cl

19 Toxicity Concentration (µg/l) Trichloronitromethane O 3 UV UV,O Genotoxicity O 3 UV UV,O 3 Control,Cl 1ppm O 3,Cl ppm O 3,Cl 4ppm O 3,Cl,Cl,1ppm O 3,Cl,ppm O 3,Cl,4ppm O 3,Cl,7ppm O 3,Cl,10ppm O 3,Cl Control,Cl 1ppm O 3,Cl ppm O 3,Cl 4ppm O 3,Cl,Cl,1ppm O 3,Cl,ppm O 3,Cl,4ppm O 3,Cl,7ppm O 3,Cl,10ppm O 3,Cl

20 Toxicity Concentration (µg/l) Trichloronitromethane O 3 UV UV,O Genotoxicity O 3 UV UV,O 3 Control,Cl 1ppm O 3,Cl ppm O 3,Cl 4ppm O 3,Cl,Cl,1ppm O 3,Cl,ppm O 3,Cl,4ppm O 3,Cl,7ppm O 3,Cl,10ppm O 3,Cl Control,Cl 1ppm O 3,Cl ppm O 3,Cl 4ppm O 3,Cl,Cl,1ppm O 3,Cl,ppm O 3,Cl,4ppm O 3,Cl,7ppm O 3,Cl,10ppm O 3,Cl

21 Repeated treatment cycle Concentration (µmol/l) % 1.9% 1.6% TTHM 1 st nd 3 rd 3.7%.8% 1% 1.3% 1.4% 0.5% 1.% 1.5% Genotoxicity 1 st nd 3 rd 0.0 Initial Control,Cl,O 3,O 3,Cl,O 3,O 3,Cl,O 3,O 3,Cl 0 Initial Control,Cl,7ppm O 3,7ppm O 3,Cl,7ppm O 3,7ppm O 3,Cl,7ppm O 3,7ppm O 3,Cl

22 Repeated treatment cycle Concentration (µmol/l) % 1.9% 1.6% TTHM 1 st nd 3 rd 3.7%.8% 1% 1.3% 1.4% 0.5% 1.% 1.5% Genotoxicity 1 st nd 3 rd 0.0 Initial Control,Cl,O 3,O 3,Cl,O 3,O 3,Cl,O 3,O 3,Cl 0 Initial Control,Cl,7ppm O 3,7ppm O 3,Cl,7ppm O 3,7ppm O 3,Cl,7ppm O 3,7ppm O 3,Cl

23 Repeated treatment cycle Concentration (µmol/l) % 1.9% 1.6% TTHM 1 st nd 3 rd 3.7%.8% 1% 1.3% 1.4% 0.5% 1.% 1.5% Genotoxicity 1 st nd 3 rd 0.0 Initial Control,Cl,O 3,O 3,Cl,O 3,O 3,Cl,O 3,O 3,Cl 0 Initial Control,Cl,7ppm O 3,7ppm O 3,Cl,7ppm O 3,7ppm O 3,Cl,7ppm O 3,7ppm O 3,Cl

24 Effect of ozone and UV on the formation of DPB during chlorination DBP DBP formation during chlorination after treatment Effect on the DBPs themselves Increase Decrease Increase Decrease Dichloroacetonitrile UV, O 3 O 3 UV* O 3 Bromochloroacetonitrile UV, O 3 O 3 - UV Chloroform UV, O 3 O Bromodichloromethane UV, O 3 O 3 - UV Dibromochloromethane UV, O 3 O 3 - UV Dichloropropanone UV, O 3 O 3 UV* O 3 Trichloropropanone UV, O UV Trichloronitromethane UV, O UV * Confirmed in Spiliotopoulou et al. (015)

25 Summary UV treatment increased the reactivity of pool water to both chlorine and ozone Ozonation of UV-treated water decreased chlorine reaction and by-product formation Genotoxic trichloronitromethane formed by ozonation was removed with UV treatment Combined UV-ozone treatment decreases chlorine byproduct formation UV-ozone treatment is predicted to improve swimming pool water quality

26 Thanks for your attention! Waqas Cheema PhD Fellow