OCCURRENCE AND FATE OF BENZOTRIAZOLES (BTRs) DURING WASTEWATER TREATMENT A.A. Mazioti1, A.G. Asimakopoulos2, N.S. Thomaidis1 and A.S. Stasinakis1 1 Department 2 Department of Environment, University of the Aegean, Greece of Chemistry, National and Kapodistrian University of Athens, Greece Uses of BTRs Metal finishing industry (Corrosion inhibitors) Brake fluids, cooling fluids, de-icing fluids Ultra-violent stabilization applications Photographic applications Dishwashing detergents 2 Chemical properties Soluble in water Slightly basic (pKa 8.2-8.8) Weak tendency to sorb onto organic matter 3 Detection in surface water- EU BTR MeBTR Loos et al. (2009) Environ Pollution 157, 561-568 4 Detection in treated wastewater- EU BTR MeBTR Loos et al. (2013) Water Res 47, 6475-6487 5 Some interesting questions…… Are they removed in a conventional STP ? If yes, which is the role of primary and secondary treatment on their removal ? Are they biodegraded ? To what extent? Which factors enhance their biodegradation? 6 Objectives of the study To investigate the occurrence and fate of selected BTRs in a Sewage Treatment Plant To study biodegradation potential of selected BTRs in activated sludge batch experiments 7 Sampling from STP of ATHENS (GREECE) Compounds Wastewater Sludge Benzotriazole, BTR 24h composite samples Grab samples Tolyltriazole, TTR 14 different days Xylytriazole, XTR Hydroxybenzotriazole, OHBTR 8 Analysis of BTRs Wastewater Sample: 50 mL Filtration Sludge Sample: 100 mg Filter Sonication pH adjustment : 3.0 ± 0.1 Solid Phase Extraction Conditioning : 10 mL CH3OH Equilibration : 10 mL acidified H2O Mixing : 10 mL CH3OH/ACN Sonication : 45 min (37 oC) Centrifugation : 10 min (4000 rpm) Washing : 2 × 5 mL acidified H2O Elution: 10 mL CH3OH/ACN Evaporation to dryness Reconstitution :1 mL CH3OH/ACN LC-MS Analysis Asimakopoulos et al. (2013) Science Total Environ 452-453, 163-171 9 RESULTS: occurrence and removal in STP Substance Influent Wastewater Effluent Wastewater Dewatered Sludge (ng L-1) (ng L-1) (ng g-1) (n=14) Frequency Mean (%) (n=14) Frequency Mean (%) Removal (%) (n =14) Frequency Mean (%) BTR 100 1175 ± 684 100 300 ± 187 60 100 114 ± 9 TTR 100 7270 ± 4324 100 3028 ± 2074 61 100 146 ± 5 OHBTR 100 240 ± 80 53 47 ± 55 88 0 < 7.6 XTR 64 11 ± 10 79 11 ± 10 16 43 4.0 ± 1 10 RESULTS: fate in STP Biodegradation/Biotransformation ? BTR: 58% TTR: 59% BTR: 40% TTR: 39% OHBTR: 12% XTR: 84% BTR: 1% TTR: 1% BTR: 1% TTR: 1% Stasinakis et al. (2013) Science Total Environ 463-464, 1067-1075 11 Activated sludge batch experiments Aerobic Aerobic + Substrate Anoxic Anoxic + Substrate Conditions Volume : 1 L BTRs: 30 μg L-1 ΜLSS: 3000 150 mg L-1 pH: 7.35 0.32 T (oC): 21.2 1.8 oC Aerobic Aerobic SRT: 8 days SRT: 20 days COD : 200 mg L-1 Abiotic NO3-N: 40 mg L-1 Duration: 72 hours Samples: 0, 4, 8, 24, 36, 48, 72 h Triplicates Activated sludge batch experiments Aerobic Aerobic + Substrate Anoxic Anoxic + Substrate Compounds Aerobic Aerobic SRT: 8 days SRT: 20 days Abiotic Benzotriazole, BTR 5-methy-1H-benzotriazole, 5-TTR 4-methyl-1H-benzotriazole, 4-TTR Xylytriazole, XTR 5-chlorobenzotriazole, CBTR 13 Analysis of BTRs Wastewater Sample: 50 mL Filtration Sludge Sample: 100 mg Filter Sonication pH adjustment : 3.0 ± 0.1 Solid Phase Extraction Conditioning : 10 mL CH3OH Equilibration : 10 mL acidified H2O Mixing : 10 mL CH3OH/ACN Sonication : 45 min (37 oC) Centrifugation : 10 min (4000 rpm) Washing : 2 × 5 mL acidified H2O Elution: 10 mL CH3OH/ACN Evaporation to dryness Reconstitution:1 mL H2O/CH3OH HPLC Analysis 14 RESULTS: Removal of target BTRs (after 72h ) Removal (%) 100 Activated sludge - Aerobic Conditions 80 60 40 20 0 BTR 4TTR 5TTR CBTR XTR -20 15 RESULTS: Partition between different phases Activated sludge - Aerobic Conditions Mass of BTR (μg) 30 25 20 dissolved 15 particulate 10 5 0 0 4 8 24 36 48 72 Time (hours) 16 RESULTS: Role of aerobic/anoxic conditions/ substrate BTR 1.0 abiotic Ct / Co 0.8 0.6 aerobic 0.4 anoxic Aerobic + substrate 0.2 Anoxic + substrate 0.0 0 20 40 60 80 Time (h) 17 RESULTS: Role of aerobic/anoxic conditions/ substrate CBTR abiotic Ct / Co 1.0 0.5 aerobic Aerobic + substrate Anoxic + substrate anoxic 0.0 0 20 40 60 80 Time (h) 18 RESULTS: Role of aerobic/anoxic conditions/ substrate XTR abiotic Ct / Co 1.0 0.5 Anoxic + substrate aerobic Aerobic + substrate anoxic 0.0 0 20 40 60 80 Time (h) 19 RESULTS: Role of SRT XTR BTR 1.0 1.0 0.6 Ct / Co Ct / Co 0.8 0.5 0.4 0.2 0.0 0.0 0 20 40 60 80 Time (h) 0 20 40 60 80 Time (h) CBTR 1.0 Ct / Co SRT : 8 days 0.5 SRT : 20 days 0.0 0 20 40 Time (h) 60 80 20 CONCLUSIONS (monitoring study) Concentrations in raw sewage: from some ng L-1 (XTR) to some μg L-1 (TTR) Concentrations in dewatered sludge: from few ng g-1 (XTR) to 150 ng g-1 (TTR) Partial removal during conventional wastewater treatment (16-88%) Minor removal due to primary and secondary sedimentation (<2%) 21 CONCLUSIONS (activated sludge experiments) BTR, CBTR and XTR are biotransformed under both aerobic and anoxic conditions No biodegradation for 4-TTR; low biodegradation for 5-TTR Biodegradation rate of studied BTRs was enhanced in the presence of substrate Higher SRT enhanced biotransformation of CBTR and XTR Half lives: XTR (14h) < CBTR (18h) < BTR (23h) (aerobic conditions + substrate) 22 FUNDING This research has been co-financed by the European Union and Greek national funds. WATERMICROPOL (www.aegean.gr/environment/watermicropol) 23 Thank you for your attention !!! 24 OCCURRENCE AND FATE OF BENZOTRIAZOLES (BTRs) DURING WASTEWATER TREATMENT A.A. Mazioti1, A.G. Asimakopoulos2, N.S. Thomaidis1 and A.S. Stasinakis1 1 Department 2 Department of Environment, University of the Aegean, Greece of Chemistry, National and Kapodistrian University of Athens, Greece
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