Poster made for the Legatum Seed Grant final presentation of my Nepal thesis and project work.

1. Kanchan TM Arsenic Filter
Nawalparasi, Nepal
Project Description: Providing safe & affordable water to rural communities
The Kanchan Arsenic FilterTM (KAF) was developed by the
Department of Civil and Environmental Engineering at MIT Claudia M Espinoza & Maclyn O Donnell
in collaboration with the Environmental and Public Health
Organization (ENPHO, Nepal) for the low-cost removal of Sampling Methodology: Arsenic Overview:
arsenic from drinking water in Nepal.
• Tested 101 filtered water and 77 groundwater
samples in 15 different villages.
Groundwater arsenic contamination is a recognized
500
problem in many areas of South Asia. However, the 450
Arsenic
Concentra?on
(μg/L)
400
uncertain performance of the KAF under various water 350
quality conditions has limited the distribution of the KAF
300
250
outside of Nepal. Our study focused on assessing the effect
200
150
of various groundwater chemical parameters on the
100
50
arsenic removal performance of the KAF.
0
1
11
21
31
41
51
61
71
81
91
101
Filter
Referance
Number
Ground
water
Filter
Outlet
Tested Parameters:
Figure 1: Overview of measured As. Error: +/-20% (As ≤100
Test Results: µg/L) and +/- 50 µg/L (As >100 µg/L).
• Arsenic
• Ferrous Iron
• pH
• Dissolved Oxygen
• Flow Rate
• Filter Age
• Phosphate, Silica, Dissolved Oxygen, Manganese, Conductivity, Flow, Age, and Location did
not affect KAF Performance
Findings:
The KAF will not perform well in groundwater conditions
• Phosphate
• Chloride
• Location
450
450
that do not promote iron corrosion.
• Electrical Conductivity
• User Survey
400
400
• Silica/Silicate
Filter
Arsenic
(μg/L)
Filter
Arsenic
(μg/L)
350
350
• Hardness (CaCO3)
• Manganese
300
300
250
250
Poor Performance Indicators:
• GW As > 200 ug/L
200
y
=
0.3662x
-­‐
18.268
200
y
=
-­‐37.155x
+
91.234
R²
=
0.1869
R²
=
0.085
• low GW Hardness
150
150
100
100
• Nail Fe(II) < 1.1 mg/L
Kathmand
50
• high GW pH
• GW Chloride < 7 mg/L
u Valley 50
0
0
50
100
150
200
250
300
350
400
450
500
0
0
0.5
1
1.5
2
2.5
Groundwater
Arsenic
(μg/L)
Ferrous
Iron
a+er
the
Nails
(mg/L)
Figure 2: As in the GW vs. FW. Error: +/-20% (As ≤100 µg/L)
and +/-50 µg/L (As >100 µg/L).
Figure 3: Fe(II) after nails vs. As in FW. Error: +/-20% (As
≤100 µg/L), +/-50 µg/L (As >100 µg/L), +/-0.03 mg/L (Fe ≤1
mg/L), and +/-20% (Fe >1mg/L).
Next Steps:
450
2.5
Incorporating local components into the KAF system to
increase iron corrosion (i.e. rock salt - NaCl) so that it
Ferrous
Iron
A+er
the
Nails
(mg/L)
400
2
can be promoted in areas with various groundwater
350
Filter
Arsenic
(μg/L)
y
=
0.0057x
-­‐
1.0882
R²
=
0.4228
300
conditions.
1.5
250
200
1
150
y
=
-­‐0.4358x
+
64.893
100
R²
=
0.0076
0.5
50
0
0
0
10
20
30
40
50
60
70
80
90
100
0
100
200
300
400
500
600
Groundwater
Chloride
(mg/L)
Hardness
in
the
Groundwater
(mg/L)
Figure 4: GW Cl vs. As in FW. Error: +/-20% (As ≤100 µg/L), Figure 5: GW hardness vs. Fe(II) after nails. Error: +/-0.03 mg/
+/-50 µg/L (As >100 µg/L), and +/-10% (Cl). L (Fe ≤1 mg/L), +/-20% (Fe >1mg/L) and +/-10% (hardness).
red solid line - Nepali arsenic drinking water standard (50 µg/L)
GW = groundwater
green dotted line - Shift from mostly well performing KAFs to both well and poor performing KAFs