In 1983, I moved to live and work in Ghana – some 40 years ago now. Back then, I was the regional supervisor on the 3000 Well Maintenance Unit in Southern and Central Ghana which was funded by the German Development Service under the Rural Water Supply programme. The project was a pioneer of its time, and included drilling boreholes alongside the installation and testing of handpumps in six of Ghana’s regions, as well as the Nanumba district, Northern Region.
We initially installed India Mark II and Moyno pumps, before dropping the Moyno due to technical problems. However, we soon realised that the India Mark II pumps faced corrosion issues. Investigation and testing (as documented by Langennegger, 1989 and Langenegger, 1994) found that the Galvanised Iron components (rods and riser pipes), when installed in water with low pH, had a propensity to rapidly corrode – leading to discolouration of the water and affecting taste, but also causing the pumps to fail prematurely as the rods broke and riser pipes developed cracks and holes and even fell into the borehole. The envisaged idea of maintenance by communities, with assistance from mechanics who could reach villages by motorcycle, was simply not feasible with such installations. Another significant issue related to corrosion of hand pump parts was the water contamination and bad taste of the water. As a result, the water coloured the food and therefore caused the population to stop using the borehole water and forced them to go back to unsafe water sources
We, therefore, had to seek alternatives. This involved field testing and collaborating with the Materials Testing Institute of the University of Darmstadt.
We looked into replacing the galvanised iron components with stainless steel. To ensure the pipes were light, we considered using 3 – 3.5 mm thick pipes, and used a threading that at the time was used in the drilling industry , known as the “rope thread”. Although Atlas Copco had patented this threading type at the time, it was later manufactured in India after the Atlas Copco design period (patent) ended.
Figure 1: Rope thread (Claus Riexinger)
The pump rods presented some challenges as well, since the AISI Stainless Steel grade 316 that we were using was subject to breakage, including the threaded parts. In collaboration with our partners at the University of Darmstadt, we were able to find ways to make this grade of stainless steel more elastic by adding 2-3 % Molybdenum. Other issues with the rods related to the use of rolled thread, which we learned was more durable than cut thread. Incorporating these materials and techniques, we were able to reduce the rod diameter from 12 mm down to 10.8mm, resulting in lighter rods which did not corrode. The only drawback was that the threads could not be cut in the field, but this was not such an issue, as there was no need to cut them when they were installed, or upon maintenance.
Figure 2: Pump installation (Claus Riexinger)
After switching to stainless steel riser pipes, we encountered another issue: -galvanic corrosion between the pipe and the water tank. This type of corrosion occurs when two dissimilar materials come into contact in solution. It was yet another challenge! Fortunately, we were able to solve this problem by replacing the existing flange with a new one made of stainless steel with an insulating gasket, into which the riser pipe could be screwed and prevent any further galvanic corrosion.
Figure 3: Ghana Modified India Mark II Handpump – water tank, spout and flange
After conducting extensive testing and collaborating with the University of Darmstadt over a period of around 4 years, we managed to solve the problem of rapid corrosion of handpumps in Ghana. The improved pump design came to be known as the Ghana Modified India Mark II, and was officially adopted by the Government of Ghana in the 1990s. Its specifications can be downloaded here.
Designing and publishing the specifications for a new pump is one thing, but the other is ensuring that these are adhered to. A series of meetings with government, donors, and NGOs working in the water sector in the 1990s, led to the agreement to no longer use Galvanised Iron. All stakeholders were on board with the change.
Of particular importance was the tremendous support and buy-in of the major donor at the time – KfW (Germany). They agreed to pay for the increased costs of the Ghana Modified Pump on new installations, which at the time was about three times more expensive than the version using Galvanised Iron. KfW also supported the rehabilitation and replacement of the pumps that had previously been installed using Galvanised Iron. As a result, we were able to remove and replace the corroded installations systematically, rather than addressing the issue in a piecemeal manner.
It is estimated that over 4,500 Ghana Modified India Mark II handpumps had been installed in Ghana by the time I left the 3000 Well Maintenance Unit in 1992. Anecdotally, I would say that 90% were working, and of the 10% out of use, they were down for maintenance/repair.
KfW took this design to Cameroon, while Danida took it to Burkina Faso and Zambia. I am not fully aware of what happened next, but I do know that ensuring the quality of stainless steel was a problem in Burkina Faso.
I am very pleased to see that Ghana Modified India Mark II handpumps are now available through the Rural Water Supply Network (RWSN), and hope that these can be of use to other countries that are struggling to overcome the rapid handpump corrosion problem.
Figure 4: Example factory inspection Modified India MKII (Claus Riexinger)
However, I have a work of caution too. Although specifications, standards, and clear procurement documents are essential, they are rendered meaningless in the absence of inspection. During my time with the 3000 Well Maintenance Unit and later as an independent consultant, I traveled to India and other places for pre-shipment inspections. I also oversaw the rejection of consignments from India and Europe due to poor quality or manufacturing mistakes. And so, I urge all of you involved in handpump procurement and installation to make sure that you ensure the quality, especially through inspection and material testing.
Ghana Modified India Mark II Drawings and Specifications
More information about Ghana Modified India Mark II (external website)
About the author: Claus Riexinger is a rural WASH expert and freelance consultant with over forty years of experience in development cooperation with Government organisations, private companies, and development agencies mainly in Botswana, Lesotho, Malawi, Germany, India, Tanzania, and Ghana.
Photo credits: Claus Riexinger
2 thoughts on “Addressing rapid handpump corrosion: the story of the Ghana Modified India Mark II”
Please send me the email address for Claus Riexinger, the author of the above article on Ghana Modified India Mark II hand pump. I want to follow up on this as the pump was introduced in Zambia for a short time. I want to learn more on this and see how this can be carried forward.
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