1 CAN S-PAC CONTROL/REDUCE FOULING IN CERAMIC MF MEMBRANE?: PRE-COAT Approach J. Z. Hamad, M.D. Kennedy, S.G.J Heijman, B.S. Hofs, G.L. Amy and J.C. Schippers. 20 November 2009

2 Ceramic Membranes: Strengths & Weakness  High Flux Operation– 150 – 210L/m 2.h  Resistant to High Temperature and Chemicals (400 0 C & pH 1-14)  Long Life (15 years) – (Polymeric 5-7 years)  BW Flux – 1,700L/m 2.h  Can easily break (brittle)

3 Limitations of Ceramic membranes  Cost almost double to polymeric  Virus, NOM & SOCs - not removed without Pre-treatment  Fouling (Particulate/Colloidal, Organic) –

4 Pretreatment  In-line coagulation (Panglish et al 2007) – PACl (1- 3.5mg/l) – Ruhr River (Average DOC 2.4mg/l) – with 1.5mg/l of Al dosage - 35% of DOC removal observed – Flux -200L/m 2 h  Adsorption with PAC (Zhao et. al 2005) – PAC (20g/l) + MF Ceramic – high Doc River water (20mg/l) - Removal of DOC was 70%. – Flux -167L/m 2.h  PACl & O 3 (Lehman and Li 2009) – PACL (1mg/l) + Ozone (4mg/l) – Source of water is secondary effluent with average TOC of 5mg/l. Average Removal of TOC was 30% - Flux was 170L/m 2.h

5 Previous Works Done Comparison of the efficient of S-PAC & N- PAC on NOM removal Removal of micro-pollutants with S-PAC pre-coats + Ceramic membrane Virus Removal

6 GOAL and OBJECTIVES Goal:  To minimise/control fouling in Ceramic membrane  Objectives  Minimising the irreversible fouling in Ceramic membrane  UV & DOC Removal  Determination of the fractions of NOM removed – (LC-OCD)

7 What is S-PAC? 10 N-PAC: d 10 =3-5; d 50 = 10μm S-PAC: d 10 =0.3; d 50 =0.8 µm N-PAC was pulverized in ball Mill for 15hrs to produce S- PAC

8 MATERIAL AND METHODS Water Source = Pre-filtered Canal Water + Tap Water 1:1 PARAMETERValue Turbidity (NTU)0.5 DOC (mg/l)5 – 5.5 UV (cm-1) To remove the Turbidity and Suspended particles Canal water was pre-filtered with 1μm

9 Membrane Characteristics DescriptionParameter Size (Diameter) 30mm (L=1 m) Pore size 0.1μm Surface Area (Blocked) 0.065m 2 Filter MaterialAluminium Oxide (α-Al 2 O 3 ) Filtration mode Dead end mode

10 Data Logger: Q, t, P &T PILOT PLANT

11 METHODOLOGY Blocking the membrane channels (46 channels out of 55) – this reduced the use of water from 60L/h to 10L/h. Pre-filtration of Delft canal water using 1µm filter (current DOC level is about 9 mg/l). Mixing the pre-filtered with tap water by ratio of 1:1 - (Raw water) Filtration of Raw water with S-PAC pre-coats (40 layers) with BW intervals of 1, 2, 3 and 4 hours (CIP was done before starting new experiment in order to restore the membrane permeability) – Average Flux of 155L/m 2 h was used Sampling for DOC,UV and LC-OCD measurements

12 OPERATIONAL PROCESSES OF THE PILOT PLANT FILTRATION CYCLE Filtration Cycle is hours. Flux = 155L/m 2.h BACKWASHING (BW)BW Flux = 1,350L/m 2.h Duration 20 seconds. AIR FLUSHING (AF)AF = Compressed Air (5 bar). Duration 30 seconds FORWARD FLUSHING (FF) FF = Feed Water at high Flux of 350L/m 2.h for 1 minute. Purpose – To remove entrapped air S-PAC Dosing in Ceramic Dosing rate 6.7L/h. S-PAC concentration = 7.5g/l. Dosing time = 30 seconds. CIP – Citric Acid (3%) membrane is soaked for 6 hrs followed by NaOCl (3,000ppm) 6 hrs

13 Duration of Filtration Cycles & Equivalent Doses Number of Layers = 40 FILTRATION CYCLE (Hours) Equivalent Dose S-PAC (mg/l)

14 RESULTS & DISCUSSIONS  Fouling Experiments  UV & DOC Removal

15 TMP increase – Blank vs 40 layers S-PAC at Ave. J = 155L/m 2.h and 1 hr filtration cycle on MF Ceramic No fouling!

16 TMP increase – Blank vs 40 layers S-PAC at Ave. J = 155L/m 2.h and 2 hrs filtration cycle on MF Ceramic 42% Fouling Reduction

17 TMP increase – 40 layers S-PAC at Ave. J = 155L/m 2.h & 3 hrs filtration cycle on MF Ceramic 30% Fouling Reduction

18 TMP increase – 40 layers S-PAC at Ave. J = 155L/m 2.h & 4 hrs filtration cycle on MF Ceramic 10% Fouling Reduction

19 DOC Removal 60% DOC Removal

20 UV Removal 70% UV Removal

21 Observations/Conclusions 40 layers of S-PAC pre-coats renewed after every 1 hour (eq. dose 40mg/l) can control both reversible and irreversible fouling (minimize the use of chemicals!). 40 layers of S-PAC pre-coats renewed after every 2 hrs (eq. dose 20mg/l) reduced irreversible fouling by 42%. 40 layers of S-PAC pre-coats used for 3 hrs filtration cycle (eq. dose 13.5mg/l) reduced irreversible fouling by 30%. 40 layers of S-PAC pre-coats applied for 4 hrs filtration cycle (eq. dose 10mg/l) reduced irreversible fouling by 10%. DOC and UV Removal of 60% and 70% was achieved respectively from surface water (DOC = 5mg/l & UV = 0.16) when 40 layers of S-PAC were used over ceramic membrane at a Flux of 155L/m 2 h and filtration cycle of 1 hour. With 2,3 and 4 hours filtration cycles DOC Removal of 32%, 26% and 23% were observed respectively while UV Removal was 45%, 39% and 34% respectively

22 Recomendations Longer Fouling experiments with higher Fluxes (170 – 210 L/m 2 h)

23 Ongoing Works LC-OCD measurements EEM measurements

24 ACKNOWLEDGEMENT EU Techneau – Funding KWR – Pilot Plant MetaWater - membranes

.

26 OPERATION: 1.) Filtration – (valve 1 & 3 open) BW vessel – valves 1,3,4 & 8 open 2.) BW–valves 10,2,4,9 open 3.) Air Flushing – valves 2,7,10 open 4.) Forward flushing–valves 1& 6 open Filtration cycle – 1 hour Backwashing –16 seconds (3liters) Air Flushing – 30 seconds (5 bars) Forward Flushing – 1 min. (150l/h) PILOT PLANT- CERAMIC MEMBRANE FILTRATION FILLING BW BW AF FF 2 ND CYCLE

27

28 Pre-treatment prior to Ceramic Membrane  Adsorption (Mixing Chambers & Static mixing) + In-line coagulation (Matsui et. al 2005) )– Low DOC water (about 1.5mg/l DOC) L/m 2.h 1.) S-PAC (1-10mg/l) + Poly Aluminium Chloride (PACl 1mg/l) 2.) N-PAC (5-40mg/l) + PACl (1mg/l)  Adsorption without Coagulation RAW 5mg/l(S- PAC) + 1mg/l(PAC l) 20mg/l(N- PAC) + 1mg/l(PAC l TOC (mg/l) Removal 71%50% RAW 5mg/l(S- PAC) 20mg/l(N- PAC) TOC (mg/l) Removal 33%8%

29 SELECTION OF PRE-TREATMENT METHOD Why PAC?Why S-PAC?Why Pre-coat? PAC can well remove both NOM and micro-pollutants by adsorption Average PAC dose of 10mg/l was recommended by CRISTAL Process for removal of pesticides on Reservoir water Fast kinetics due to smaller particles 5mg/l of S-PAC worked better than 20mg/l of N-PAC in NOM removal (Matsui et al. 2005) No pre-loading a new layer of S-PAC is introduced when a new filtration cycle starts Exhausted layer is removed by Backwashing Form a very thinly layer on the membrane channels so contact time is < 1 second – recirculation is not needed R