Arsenic Removal by Electrocoagulation- A Socially Sustainable Water Treatment Technology
The University of Oklahoma 2013 WaTER conference
North Maharashtra university, Jalgaon
CSIR-National Environmental Engineering Research Institute, NEERI, Nagpur
INDIA
23-25 September, 2013
ASMITA JADHAV
General Outline: Arsenic
Existing Treatment Technologies
Objectives
Electrocoagulation
Arsenic removal by Electrocoagulation
Results
Conclusion
SCHEME OF PRESENTATION
THE DISTRIBUTION OF ARSENIC OVER THE WORLD
• Adsorption and ion Exchangers
• Coagulation/Filtration
• Ion-exchange Resins
• Reverse Osmosis
• Membrane Filtration
• Electrocoagulation
EXISTING TREATMENT TECHNOLOGIES FOR ARSENIC REMOVAL
The objective of the research is
• Review of existing arsenic removal technologies for potable water supply
• To study and develop a treatment technology for the removal of arsenic from drinking water to meet the maximum contaminant level of Arsenic based on electro-coagulation using iron electrode
– Laboratory experiments for arsenic removal
– Experimental Parameters
• Current Intensity
• Initial Arsenic Concentration
• Iron concentration
• pH
OBJECTIVES OF THE RESEARCH
Electrocoagulation (EC) is an electrochemical technology for the treatment of water and wastewater.
ELECTROCOAGULATION
Fig. Schematic representation of Electrocoagulation-cell
Laboratory Scale Batch Electrocoagulation
• 15L Electrochemical Batch Reactor
• Iron Electrodes (99% purity, 2 mm thickness; effective area 180 cm2 on each side)
• The plates were placed 10mm apart in the batch cell.
• The mono-polar 3 electrodes connected in parallel were used in electrocoagulation cell for the experiments.
• A direct current (DC) supply (TESTRONIX 34C, 1 - 15V, 0 - 5 A, Digital Display)
ARSENIC REMOVAL BY ELECTROCOAGULATION
• Batch experiments were performed in the laboratory at ambient temperatures ranging from 27±1°C
• Experiments were conducted using 15L tap water spiked with Arsenic
• The water is continuously circulated using submersible water pump to ensure complete mixing
• Arsenic concentration was analyzed (using ICP-OES) at fixed time interval in the reactor for first 30 minutes when the current was supplied
BATCH-EXPERIMENTS OF ELECTROCOAGULATION
RESULTS Arsenic removal By Electrocoagulation:
Effect of pH on arsenic removal:
• It is observed that with initial concentration of 100µgL-1, took
less than 30 min for the dissolved concentration to drop below
10µgL-1, pH was 6.5 & current was 0.5A with current processing
time 20 min and kept back for settlement for approximately 60
to 90 minutes.
• At pH 3.5 and 9.5 it took more than 80 minutes to drop below
50µgL-1. Similarly experiments were carried out with different
initial concentration; 100, 150, 200µgL-1
0
50
100
150
200
0 10 20 30 40 50 60 70 80 90 100 110 120
Resi
du
al
Ars
en
ic c
on
cen
trati
on
(µg
L-1
)
Time (min)
75µgL-1
100µgL-1
150µgL-1
200µgL-1
0
50
100
150
200
0 10 20 30 40 50 60 70 80 90 100 110 120
Resi
du
al
Ars
en
ic c
on
cen
trati
on
(µg
L-1
)
Time(min)
75µgL-1
100µgL-1
150µgL-1
200µgL-1
Figure 1: Effect of initial arsenic concentration at pH 3.5 and 0.5 A
Figure 2: Effect of initial arsenic concentration at pH 3.5 and 1 A
RESULTS EFFECT OF PH ON ARSENIC REMOVAL :
0
50
100
150
200
250
0 10 20 30 40 50 60 70 80 90 100 110 120
Resi
du
al
Ars
en
ic c
on
cen
trati
on
(µg
L-1
)
Time(min)
75µgL-1
100µgL-1
150µgL-1
200µgL-1
0
50
100
150
200
250
0 10 20 30 40 50 60 70 80 90 100 110 120
Resi
du
al
Ars
en
ic c
on
cen
trati
on
(µg
L-1
)
Time(min)
75µgL-1
100µgL-1
150µgL-1
200µgL-1
Figure 3: Effect of initial arsenic concentration at pH 6.5 and 0.5 A
Figure 4: Effect of initial arsenic concentration at pH 6.5 and 1A
0
50
100
150
200
0 10 20 30 40 50 60 70 80 90 100 110 120
Co
nce
ntr
ati
on
of
Ars
en
ic(µ
gL
-1)
Time(min)
75µgL-1
100µgL-1
150µgL-1
200µgL-1
0
50
100
150
200
0 10 20 30 40 50 60 70 80 90 100 110 120
Co
nce
ntr
ati
on
of
Ars
en
ic(µ
gL
-1)
Time(min)
75µgL-1
100µgL-1
150µgL-1
200µgL-1
Figure 5: Effect of initial arsenic concentration at pH 9.5 and 0.5 A
Figure 6: Effect of initial arsenic concentration at pH 9.5 and 1 A
VARIATION OF PH WITH TIME
0
1
2
3
4
5
6
7
8
9
10
0 10 20 30 40 50 60 70 80 90 100 110 120
pH
Time (min)
3.5
6.5
9.5
0
1
2
3
4
5
6
7
8
9
10
0 10 20 30 40 50 60 70 80 90 100 110 120
pH
Time (min)
3.5
6.5
9.5
Figure 7: Variation of pH with Time at 0.5A
Figure 8: Variation of pH with Time at 1A
EFFECT OF INITIAL ARSENIC CONCENTRATION
80.00
85.00
90.00
95.00
0 100 200 300% R
em
ov
al
Eff
icie
ncy
Initial Concentration(µgL-1)
% Removal efficiency
Figure 9: Removal Efficiency (%) of Arsenic at pH 6.5 and 0.5A
85
90
95
100
0 100 200 300
% R
em
ov
al
Eff
icie
ncy
Initial Concentration(µgL-1)
% Removal efficiency
Figure 10: Removal Efficiency (%) of Arsenic at pH 6.5 and 1A
Range 75-200µgL-1
EFFECT OF CURRENT INTENSITY
0
50
100
150
0 10 20 30 40 50 60 70 80 90 100 110 120
Re
sid
ual
Ars
en
ic c
on
cen
trat
ion
(µgL
-1)
Time(min)
DC:0.5A at 3.5pH
DC: 1 At 3.5pH
DC:0.5A At 6.5pH
DC: 1 A At 6.5pH
DC:0.5A At 9.5pH
DC: 1 A At 9.5pH
Figure 12: Effect of current intensity on Arsenic removal in 100µgL-1.
CONCLUSION
Based on present work following conclusions are drawn:
pH 6.5 was found to be most appropriate for treating the drinking water for arsenic removal by Electrocoagulation.
In electrocoagulation increase in pH is observed but the increase is within safety limit prescribed by WHO ( as per the limit it is safe to drink water upto pH of 8.5).
The electrocoagulation process was able to decrease the residual arsenic concentration to 10µgL-1 and meet the drinking water standard (Bureau of Indian Standard (BIS) IS: 10500: 2012) with iron electrode.
Electrocoagulation is an effective community based chemical mitigation technique when combined with solar power as an electricity generation source.
REFERENCES
1. A. M. Haque, H. M. Thwe, H.P.W. Jayasuriya, M. Z. Hossian, M. Rahman, M
Harun-ur-Rashid and K. Matsumura (2007), Groundwater Arsenic
Contamination: Food Safety and Human Health Hazard in Banaladesh, CMU.J.
Nat. Sci, vol.6 (2), 333.
2. Ahmed. F., Jalil, M.A., Ali, M.A., Hossain, M.D. and Badruzzaman, A.B.M.(
2000), An overview of arsenic removal technologies in BUET, In Bangladesh
Environment-M. F. Ahmed (Ed.), Bangladesh Poribesh Andolon, p.no.177-188.
3. Alan H. Welch, Kenneth G. Stollenwerk,(2003) Arsenic in ground water, by
Kluwer Acedemic Publishers,(U.S).
4. Badal Kumar Mandal, Kazoo T. Suzuki (2002), Arsenic round the world: a
review, Talanta, vol.58, p. no.201-235.
5. Balasubramanian, N., Madhavan, K. (2001), Arsenic removal from industrial
effluent through electrocoagulation. Chem. Eng. Technol. vol.24 (5), p. no. 519–
521.
6. Bart Van der Bruggen, Carlo Vandecasteele,(2003), Removal of pollutants from
surface water and groundwater by nanofiltration: overview of possible
applications in drinking water industry, Environmental pollution, vol.122 p. no.
435-445.
ACKNOWLEDGEMENT
CSIR-National Environmental Engineering Research Institute, Nagpur , India-440020
• Dr. Pawan Labhasetwar • Er. Subhash Andey • Piyush Mahore • Dr. Pranav Nagarnaik • Prashant Deshmukh
North Maharashtra University, Jalgaon, India-425001 • Dr. S.T. Ingale • Dr. Nilesh Wagh
The University of Oklahoma & The WaTER Center • Dr.David Sabatini • Dr. Jim Chamberlain
THANK YOU.....
