Presentation given at SKYREC seminar, 2011

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Presentation given at SKYREC (2011) seminar describing results of activated carbon and UV treatment in organic material removal from deionized recovery boiler make-up water.

Transcript of Presentation given at SKYREC seminar, 2011

  • 1. Activated carbon and UV treatment in TOC removal field testsTero Luukkonen, 20.10.2011

2. Main participants in the project 3. Contents Active carbon tests TOC reductions Effects on conductivity of water Silica UV treatment tests TOC reductions Effects of number of UV lamps, wavelenght, H2O2 and TiO2 catalyst LC-OCD measurement results 4. Active carbon tests: experimental set-upWater treatment process of Stora Enso Oulu mill 5. Active carbon tests: experimental set-upTest scheme of pilot scale AC filters.demineralized waterTest scheme of full scale AC filters. 6. AC 1MBAC 2 7. Active carbon: TOC reductions Pilot scale AC filters Full scale AC filtersResidual TOC removal 38 57 % Residual TOC removal 40 65 % 8. Active carbon: LC-OCD results (after ~ 10 months in use) demineralized water: 155 ppb 529AC1: 62 ppb23182272031026MB: 125 ppb 1490AC2: 37 ppb3220 140 4917 030 5 9. AC vs. RO (LC-OCD) AC + MB + AC: 37 ppb 20 14RO (Ahlholmens Kraft): 42 ppb 17 3 0 5AC: 62 ppb32 1834 310 9030 2 10. Active carbon: conductivity Pilot scale AC filters and MB unit 0,090Full scale AC filter0,0700,3000,060 0,2500,050 0,040 0,030 0,020 0,010 0,000 AC117.5.11 MB31.7.11AC2Conductivity (mS/m)Conductivity mS/m0,0800,200 0,150 0,100 0,050 0,000 scale AC11.6.11 MB 11. Active carbon: conductivity, some remarks MB unit needed after AC to decrease conductivity Correlation between TOC removal efficiency and conductivity was a bit unclear (linear R2 only ~ 0,5) Conductivity rise at AC bed was due release of ionized compounds from AC itself not ionization of TOC AC bed was not operating as biological filter because of low nutrient content of water 12. Active carbon: silica0,250 0,200 Silica (g/l) Silica causes severe scale problems in water-steam cycle Measured on-line during full scale test New AC bed released silica for ~ 2 weeks Silica was removed with subsequent MB0,150 0,100 0,050 0,000 23.3.1112. 13. UV treatment: experimental set-up Influent waterUV champersDemineralized waterUVMB unit MB 14. UV treatment: results One chamber: max. 30 % TOC removal Four chambers: only 4 % increase in TOC removal Effect of TiO2 catalyst: negligible Effect of H2O2: ? (experimental set-up failed: plastic piping released organic compounds) Effect of wavelenght: Medium pressure lamp (wavelenght peaks at 254 nm and 185 nm): better (30 % TOC removal) Low pressures lamp (wavelengh peak sharply at 185 nm): not that effective 15. TiO2 catalyst TiO2 should enhance hydroxyl radical formation This type of catalyst (porous net) had no effect 16. UV treatment: H2O2 dosingH2O2 (35 %), elevated to ~ 40 m from dosing pointFlowmeter 17. Unknown peaks in LC-OCD chromatogram which are probably plastic additives 18. UV treatment: LC-OCD demineralized water: 155 ppb 529UV: 108 ppb 190 6 02272360 26UV + MB: 113 ppb 4 0477 0 1687 19. Conclusions: AC Active carbon can remove up to 40 - 60 % of residual organic material (TOC) AC bed lifetime before regeneration is at least 10 months Subsequent MB is needed to remove elevated conductivity and silica AC works fine in full scale 20. Conclusions: UV UV treatment was able to remove up to 30 % of residual TOC Removal efficiency did not improve with: Lower wave lenght (more energy) H2O2 (oxidant) TiO2 (catalyst) Number of UV chambers (contact time) Possible reason for this: water should be pretreated with e.g. RO (this is normal procedure in microelectronic or pharmaceutical industry water treatment)