small scale electrochemical disinfection system with specially...
TRANSCRIPT
-
Small scale electrochemical disinfection system with specially coated electrodesC. Sousa, K.M. Śmiech, A. W. Jeremiasse, L.L.F. Agostinho
Athens, September 2016
1
-
Outlook
• Background: (Electrochemical) water disinfection
• Methods• Experimental setup• Results:
Disinfection efficiency Produced disinfectants Disinfection byproducts and heavy metals
• Summing up
2
-
Water disinfectionImportant for preventing the spreading of waterborne diseases
1Martinez-Huitle, C., & Brillas, E. (2008) Electrochemical alternatives for drinking water disinfection. Angewandte Chemie
International Edition 47 (11), 2-10
3
Methods1:
• Chemical e.g. Cl2, ClO, O3• Physical e.g. UV• Physical-chemical e.g. electrochemical
Electrochemical disinfection efficiency:• Electrolyte• Current (density)• Electrode material
• BDD• MMO
-
Methods
• 2 electrochemical cells• 2 MMO types (Ru, Ir, Ti)
ON2012 ON2038
• Total flowrate = 4 m3 h-1
• Cl- concentration = 49 mg L-1
• Disinfection efficiency for 3 bacteria and 1 virus E.coli S. epidermidis R. terrigena bacteriophage MS2
• Analysis for THM• Analysis for heavy metals
4
-
Experimental setup
5
-
6,19
0
6,22
0
6,16
0
6,01
0
6,19
0
6,39
0
6,22
0
6,43
0
6,36
00
2
4
6
8
10
12
14
16
18
20
IN OUT IN OUT IN OUT
Log
(CFU
/mL)
E. coli S. epidermidis R. terrigena30 min.60 min0 min 30 min
Disinfection efficiency
Bacteria*: > log 6 disinfection
6
Virus**: log 3 – log 5 disinfection
* Method: Heterotrophic plate count. Standard Methods for the Examination of Water and Wastewater (APHA).
** Method: ISO 10705-1:1995 Detection and enumeration of bacteriophages. Part 1: enumeration of F-specific RNA bacteriophages.
5,78
1,16
5,78
0,78
5,72
0,00
5,62
2,69
5,69
2,27
6,31
2,54
0
2
4
6
8
10
12
14
IN OUT IN OUT IN OUT
Log(
PFU
/mL)
MS2 cell 2038 MS2 cell 2012
0 min 30 min 60 min
-
Produced disinfectants
*Method: ISO 7393/1:1998 Water quality -- Determination of free chlorine and total chlorine -- Part 1: Titrimetric method using N,N-diethyl-1,4-phenylenediamine.
**Method: H. Bader & J. Hoigné (1981) Determination of ozone in water by the indigo method. Water Research 15(4), 449-456
7
IN OUT 2012 OUT 2038 range
Free Cl (mg L-1)* 0 0,37 1,38 0,5 – 3
O3 (mg L-1)** 0 0,33 0,36 0,1 – 0,8
Active chlorine production: > 90% Coulombic efficiency
-
Disinfection byproducts and heavy metals
• Total THM ~0,6 μg L-1 as AOX
•
-
Summing up• Small scale (2 x 2 m3 h-1) electrochemical disinfection system with specially
coated electrodes (MMO with Ru and Ir)
• Treatment of waters with low Cl- content (49 mg L-1) without salt addition
9
• Disinfection efficiency:
• bacteria: > log 6• virus: log3 – log 5
• Produced disinfectants included:
• Free Cl: 0,5 – 3 mg L-1
• O3: 0,1 – 0,8 mg L-1
• THM: ~0,6 μg L-1 as AOX, i.e.
-
Acknowledgements
10
-
Thank you very much!
Questions?
11