Urban Water Security Research Alliance Removal of organic matter and micro- pollutants using the ozone/BAC process for recycled water production Dr Julien Reungoat M.J. Farré, M. Rattier, F.X. Argaud, W. Gernjak, J. Keller - AWMC B.I. Escher, M. Macova - Entox Enhanced Treatment Project Science Forum, 19-20 June 2012
Effluent organic matter in secondary effluent Nutrient Removal WWTP NOM Micropollutants Effluent Effluent DBPs organic matter organic matter AOC precursors Taste Odour Colour
Effluent organic matter in secondary effluent Nutrient Removal Membrane filtration WWTP Riverbank filtration Oxidation Aquifer recharge Adsorption NOM Micropollutants Effluent Effluent DBPs organic matter organic matter AOC precursors Taste Odour Colour Indirect Non-potable Irrigation potable reuse reuse
Ozone/BAC O 3 Effluent organic matter BAC O 3
BNR WWTP The plants studied 40,000 EP - 8,000 m 3 /day BNR WWTP Pre-ozonation BNR WWTP 11,000 EP - 900m 3 /day 10,000 EP - 2,000 m 3 /day (~0.10 mg O3 /mg DOC ) Plant C Dissolved air flotation Plant A Plant B Rapid sand filtration Rapid sand filtration and sand filtration Ozonation Ozonation Ozonation (0.4-0.5 mg O3 /mg DOC ) (0.2-0.3 mg O3 /mg DOC ) (0.6-0.8 mg O3 /mg DOC ) BAC BAC BAC (45 min) (9 min) (18 min) Commissioned in 1999 Commissioned in 2003 Commissioned in 2002 ≈ MF membranes Replaced in March 2008 Ozone disinfection 300,000 bed volumes Half replaced in 2009 UV disinfection ≈ ½ ≈ (0.2 µm) (~0.30 mg O3 50,000 bed volumes /mg DOC ) 95,000 bed volumes ½ ≈ 13,000 bed volumes UV disinfection
Water quality before ozonation Plant A Plant B Plant C T ( ° C) 22.0 22.6 ‐ 28.5 ‐ pH 6.6 ‐ 6.7 6.7 ‐ 7.1 6.7 ‐ 6.9 Conductivity (µS) 879 ‐ 910 392 ‐ 507 519 ‐ 563 DOC (mg L ‐ 1 ) 6.5 ‐ 8.1 5.8 ‐ 6.6 4.2 ‐ 5.8 ≤ PO 4 3 ‐ ‐ P (mg L ‐ 1 ) 0.02 0.22 ‐ 2.00 < 0.02 ‐ N (mg L ‐ 1 ) NH 4 < 0.03 0.22 ‐ 0.45 0.18 ‐ 1.36 ‐ N (mg L ‐ 1 ) NO 2 < 0.02 0.03 ‐ 0.06 <0.02 ‐ 0.04 ‐ N (mg L ‐ 1 ) NO 3 < 0.02 ‐ 0.95 0.18 ‐ 0.47 0.39 ‐ 1.14
Removal of DOC Plant A Plant B Plant C T ( ° C) 22.0 22.6 ‐ 28.5 ‐ pH 6.6 ‐ 6.7 6.7 ‐ 7.1 6.7 ‐ 6.9 Conductivity (µS) 879 ‐ 910 392 ‐ 507 519 ‐ 563 DOC (mg L ‐ 1 ) 6.5 ‐ 8.1 5.8 ‐ 6.6 4.2 ‐ 5.8 ≤ PO 4 3 ‐ ‐ P (mg L ‐ 1 ) 0.02 0.22 ‐ 2.00 < 0.02 ‐ N (mg L ‐ 1 ) NH 4 < 0.03 0.22 ‐ 0.45 0.18 ‐ 1.36 ‐ N (mg L ‐ 1 ) NO 2 < 0.02 0.03 ‐ 0.06 <0.02 ‐ 0.04 ‐ N (mg L ‐ 1 ) NO 3 < 0.02 ‐ 0.95 0.18 ‐ 0.47 0.39 ‐ 1.14
Micropollutants 41 targeted compounds: Mainly PPCPs and a few pesticides. Wide range of physico-chemical properties. Some known to be easily removed in WWTP, others not.
Micropollutants 41 targeted compounds: Mainly PPCPs and a few pesticides. Wide range of physico-chemical properties. Some known to be easily removed in WWTP, others not. Plant A Plant B Plant C Quantified 35 38 36 < LOQ 3 1 5 Not quantifiable 3 2 0 Concentrations ranged from a few ng/L to more than 1 µg/L. For a given compound, the concentration remained in the same order of magnitude regardless of sampling date and plant sampled.
Removal of micropollutants: ozonation Low reactivity compounds O 3 reactive compounds
Removal of micropollutants: BAC <20% <20% >80% 20 - 80% >80% 20 - 80% Onesios et al., 2009 in Biodegradation, 20(4), 441-466
Removal of micropollutants: O 3 +BAC Plant A Plant C Plant B 100 80 Removal (%) 60 40 20 0 D n l e e m n c n e n e l e n l n l n l e n e e l r m e n o i o i o o y z a r e n n o o n i d d e e i n i n l n i - l a c l p o l c o d p i r o o o o 4 n x r h i i n r i i i f i i i a y y e p m m z o t d l z a x r o o p u r n r y n a , p i e o f p m m b a a a 2 f e z p d i m l i r o r n e f f a e r a t r c o D o p a a i i i x f a z o o p n t h t o f h e n o i a l s r r a n u l y m o r W A C a i l t a a i p e t r a r D c o t r h T l e r i x b e h o h h n m m e o t N S T i e R r M P i o m D I e t r t t C u P r y G i e a a o D P x V F i r l m t b r o E h e T r R c a c a o A h C r p d l y u H S
Bioanalytical tools Microtox: non-specific toxicity takes into account all micropollutants, by-products,… expressed as baseline-TEQ (mg/L) E-screen: estrogenicity expressed as estradiol equivalent concentration (EEQ) limit of quantification = 0.01 ng/L Plant A Plant B Plant C Baseline-TEQ (mg/L) 1.83 - 2.72 1.50 - 2.01 1.10 - 1.84 EEQ (ng/L) 0.98 - 1.73 1.13 - 1.44 0.57 - 1.53
Toxicity removal Effect of ozonation similar in the three plants Effectiveness of BAC increased from 9 to 18 minutes EBCT but not further
Toxicity removal Ozonation very effective (estrogenic moieties are very reactive with molecular ozone) Effectiveness of BAC difficult to assess due to low levels
Disinfection by-products precursors Formation potential (µg/L) Chloroform 224±21 FP reduction (%) Bromodichloromethane 53±6 THMs Dibromochloromethane 11±2 O 3 80 Bromoform < 1 60 Total THMs 289±26 Monochloroacetic acid < 10 40 Dichloroacetic acid 154±32 Trichloroacetic acid 143±17 20 Bromochloroacetic acid 30±6 HAAs 0 Monobromoacetic acetic < 5 THMs HAAs NDMA Dibromoacetic acid < 5 Total HAAs 327±53 NDMA (ng/L) 327±22
Disinfection by-products precursors Formation potential (µg/L) Chloroform 224±21 FP reduction (%) Bromodichloromethane 53±6 THMs Dibromochloromethane 11±2 O 3 80 O 3 +BAC Bromoform < 1 60 Total THMs 289±26 Monochloroacetic acid < 10 40 Dichloroacetic acid 154±32 Trichloroacetic acid 143±17 20 Bromochloroacetic acid 30±6 HAAs 0 Monobromoacetic acetic < 5 THMs HAAs NDMA Dibromoacetic acid < 5 Total HAAs 327±53 NDMA 327±22
Take home messages Ozonation: removal of OMPs depends on compound and ozone dose reduction of non-specific toxicity > 90% reduction of estrogenicity removal of NDMA precursors Biological activated carbon: removes OMPs reduces non-specific toxicity / removes O 3 by-products removal of THMs and HAAs precursors Combination: > 90% removal of OMPs up to 70% reduction of non-specific toxicity > 90% reduction of estrogenicty (<0.01 ng/L EEQ) removal of DBPs precursors
Acknowledgements Beate Escher Miroslava Macova Wolfgang Gernjak François Xavier Argaud Maria Jose Farré Maxime Rattier Jurg Keller Jelena Radjenovic Beatrice Keller Yvan Poussade
Urban Water Security Research Alliance THANK YOU www.urbanwateralliance.org.au
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