E.L. Batsari 1, A.K. Tolkou 1, A.I. Zouboulis 1, P.K. Gkotsis 1, E.N. Peleka May 2015, President Hotel, Athens

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1 21-23 May 2015, President Hotel, Athens International Conference Industrial Waste & Wastewater Treatment & Valorisation Fouling control in MBR systems: comparison of several commercially applied coagulants E.L. Batsari 1, A.K. Tolkou 1, A.I. Zouboulis 1, P.K. Gkotsis 1, E.N. Peleka 1 1 Laboratory of General and Inorganic Chemical Technology, Chemical Technology and Industrial Chemistry Section, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki, Greece

2 Presentation topics Membrane bioreactor technology Membrane fouling-membrane fouling control Coagulation-Flocculation in MBR systems Lab-scale MBR system Results Conclusions 2

3 Membrane Bioreactor (MBR) technology Organic biodegradation in an aeration tank with membrane filtration Sedimentation 3

4 Membrane Bioreactor (MBR) technology Biomass Separation MBR Submerged/Immersed MBR Side-stream/External MBR 4

5 Membranes in MBR Separation range Microfiltration (MF) Ultrafiltration (UF) Nanofiltration (NF) Reverse Osmosis (RO) Material A) Organic polymers Polypropylene - PP Polyethylene - PE Polysulphones - PSU Polyvinylidenefluoride - PVDF etc B) Ceramic/Inorganic (e.g. Al 2 O 3, TiO 2, ZrO 2 etc) 5

6 Membranes in MBR Membranes in MBR Configuration A) Flat sheet B) Hollow fiber C) Tubular 6

7 Membrane fouling FOULING A process by which a variety of species present in the water increase the membrane resistance by: (1) adsorption onto the pore surfaces within the bulk membrane material (pore restriction) (2) complete pore-blocking (3) depositing onto its surface 7

8 Membrane fouling EPS (mainly proteins and polysaccharides bound EPS soluble EPS or lbeps tbeps SMP 8

9 Common methods applied for fouling mitigation A.Optimal operation of MBR process 1.Permeate flux reduction 2.Aeration increase - Gas/liquid flow to achieve shear rates at the surface - Partly intermittent & coupled with filtration breaks B. Physical cleaning 1.Filtration breaks Periodical discontinuity of filtration (e.g. every 10 min for 1 min) 2. Backflushing Periodically with permeate (e.g. every 3-10 min for s) C. Chemical cleaning (NaClO, C 6 H 8 O 7 etc) 9

10 Primary objective PRIMARY OBJECTIVE The development of an integrated technology for fouling control in MBRs by the: Addition of specific chemicals that! will enhance the coagulation & flocculation of compounds, which are responsible for fouling 10

11 Lab-scale MBR system

12 Membrane characteristics Zenon Membrane, ZW-1 Membrane specifications Model Configuration Operation Material Pore size Surface area Maximum TMP Typical operating TMP Operating ph range Maximum cleaning temperature ZW-1, submersible module Hollow Fibre Dead-end, Outside/In Polyvinylidene fluoride (PVDF) 0.04 μm m 2 62 kpa (0.62 bar) kpa ( bar) o C 12

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15 Preliminary experiments under constant Q P (presence of biomass in the system) TS = mg/l VSS = 6770 mg/l NVSS = 1570 mg/l VTS = 7910 mg/l ph = 7.34 Biomass characterization Daily measurements (in the Mixed Liquor): A) SS = 5000 mg/l B) SVI = ml/g 15

16 Synthetic municipal wastewater Synthetic wastewater composition Synthetic wastewater characterization Substance Concentration (mg/l) Peptone 480 Meat extract 330 Urea 90 K 2 HPO 4 84 NaCl 21 CaCl 2 2H 2 O 12 BOD = 300 mg/l COD = 650 mg/l Tot-N = 70 mg/l NH 4+ -N = 7 mg/l NO 3- -N = 1,5 mg/l ph = 7,4 TOC =200 mg/l Conductivity = 1,2 ms/cm UV 254 absorbance = 0,6 MgSO 4 7H 2 O 6 (OECD, Technical report, 2010) 16

17 Commercially applied coagulants Indicative commercial available coagulants used Type Description Inorganic Pre-polymerized PAC A9-M 0.1 M 4.5 Al% + polyamine FeCl 3 6H 2 O Fe salt 0.1 M Organic CPE-cationic FO4350SSH polyelectrolyte 0.01% w/w 17

18 Bench-scale experiments Time to filter (TTF) test equipment (APHA 1992) (Reversible fouling) P = 510 mbar V filt = 100 ml 18

19 Bench-scale experiments SMP (Soluble microbial product) (Irreversible fouling) Phenol-Sulfuric Acid Method (Dubois Method) Colorimetric method for the determination of carbohydrate at UV 490 nm Phenol H 2 SO 4 Vortex 30 s Stay for 10 min Stay for 30 min UV 490 nm 19

20 Filterability tests Effect of different coagulants on sludge filterability Membrane fouling results 20

21 Membrane fouling results TMP progress TMP progress before and after the addition of PAC-A9-M (100 mg Al/L) 21

22 TMP progress Membrane fouling results TMP progress before and after the addition of CPE FO4350SSH (10 mg/l) 22

23 TMP progress Changes of TMP by FeCl 3 6H 2 O addition100 mg Fe/L Membrane fouling results 23

24 SMP residual concentration Membrane fouling results SMP residual concentration after the addition of CPE FO4350SSH, PAC-A9-M and FeCl 3 6H 2 O, in the labscale MBR 24

25 Lab-scale MBR efficiency Organic removal efficiency in the lab-scale MBR 25

26 Lab-scale MBR efficiency Ammonium removal efficiency in the lab-scale MBR TOC Turbidity, NTU determination 26

27 Conclusions A) Membrane fouling assessment Coagulant addition clearly enhanced sludge filterability and reduced significantly SMP concentration FeCl 3 6H 2 O (100 mg/l) B) MBR operation & removal efficiency The lab-scale MBR operated successfully with a medium strength synthetic municipal wastewater Remarkable behaviour was observed in terms of most physical/chemical parameters. 27

28 Acknowledgements The financial support through the co-financed by the European Union and the Greek State programme EPAN-II/ ESPA: 'SYNERGASIA II' Project FOUL-MEM, (11SYN ) is gratefully appreciated. THANK YOU FOR YOUR ATTENTION