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Dear Sarah,
High iron can come from two possible sources: 1) The aquifer 2) Corrosion of IM2 riser pipes and rods
IM2 pumps that use galvanised iron (GI) riser pipes and rods are prone to corrosion in aggressive groundwater conditions (where the pH is below 6.5). The corrosive action of the groundwater causes pipes to rapidly rust resulting in release of iron into the water, formation of leaks in the pipes and joint failure. The high iron is unpleasant to users and although there is no direct health impact, it can cause users to abandon sources and seek alternative (often less safe) options. It also causes rapid pump failure.
It is possible to trace the origin of the iron by using a Palintest colour comparitor kit with Iron MR1 and MR2 reagents. You take a sample at the beginning of pumping (very early in the morning) and take samples every 30 min of continuous pumping for 2 hours. If you see iron concentrations reduce over that time it is coming from materials in the pump. If you see iron concentrations remain constant at a high level for the duration of pumping it is most likely coming from the aquifer.
The corrosion issue has been known about since the 1980s but because implementers generally tend to install pumps and walk away without any followup with communities it has gone unchecked for a long time. There is sometimes an assumption that the iron comes from the aquifer so some implementers have installed iron treatment plants onto the end of pumps to remove the iron. This seems ironic since it was possibly them who introduced the iron into the borehole in the first place.
If the problem is identified as emanating from the GI rods and riser pipes an alternative is to use stainless steel riser pipes and rods (of the right grade). These can be procured from some of the big pump manufacturers in India (APEX, Ajay etc).
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No.2 Revision
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Dear Sarah,
High iron can come from two possible
sources:
sources:
1) The
aquifer
aquifer
2) Corrosion of IM2 riser pipes and rods
IM2 pumps that use galvanised iron (GI) riser pipes and rods are prone to corrosion in aggressive groundwater conditions (where the pH is below 6.5). The corrosive action of the groundwater causes pipes to rapidly rust resulting in release of iron into the water, formation of leaks in the pipes and joint failure. The high iron is unpleasant to users and although there is no direct health impact, it can cause users to abandon sources and seek alternative (often less safe) options. It also causes rapid pump failure.
It is possible to trace the origin of the iron by using a Palintest colour
comparitor
comparator
kit with Iron MR1 and MR2 reagents. You take a sample at the beginning of pumping (very early in the
morning) and take samples every 30 min of continuous pumping for 2 hours. If you see iron
concentrations reduce over that time it is coming from materials in the pump. If you see iron
concentrations remain constant at a high level for the duration of pumping it is most likely coming
from the aquifer.
The corrosion issue has been known about since the 1980s but because implementers generally tend to install pumps and walk away without any followup with communities it has gone unchecked for a long time. There is sometimes an assumption that the iron comes from the aquifer so some implementers have installed iron treatment plants onto the end of pumps to remove the iron. This seems ironic since it was possibly them who introduced the iron into the borehole in the first place.
If the problem is identified as emanating from the GI rods and riser pipes an alternative is to use
stainless steel riser pipes and rods (of the right grade). These can be procured from some of the
big pump manufacturers in India (APEX, Ajay
etc).
etc.).
Vinny