Tag: corrosion

Addressing rapid handpump corrosion: the story of the Ghana Modified India Mark II

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

Corrosion de la pompe à main et qualité des matériaux : Un défi pour le Burkina Faso et le reste du monde

Au Burkina Faso, le nombre élevé de forages équipés d’une pompe à motricité humaine (PMH) qui dysfonctionnent ou qui nécessitent de grosses réparations quelques années seulement après leur construction est alarmant. Les audits techniques effectués en 2013 et 2014 au Burkina Faso sur des forages équipés de PMH ont révélé des situations préoccupantes en termes de qualité de l’eau, de matériel inadapté aux profondeurs des puits et de pompes non-conformes. Dans plus d’un tiers des cas, les forages équipés de PMH dysfonctionnent ou deviennent même totalement inutilisables en moins de quelques années. Entre 0.6 milliards de FCFA (0.9 million d’€) et 2.9 milliards de FCFA (4,5 millions d’€) d’investissements annuels seraient ainsi perdus du fait de l’installation de PMH de qualité médiocre et de diverses malfaçons lors des travaux de construction. Chaque année, plus de 130 000 personnes bénéficient d’un service d’approvisionnement en eau dont la pérennité n’est de ce fait pas assurée au-delà des premières années.

La corrosion des PMH est un phénomène connu depuis plus de 30 ans ; elle demeure pourtant un problème majeur au Burkina Faso car les gouvernements successifs et les agences d’aide au développement ont continué d’installer des pompes fabriquées à partir de matériaux inadaptés. Ces pratiques ont généré des coûts d’entretien élevés, de multiples pannes et le rejet de nombreux points d’eau par les communautés car l’eau y était de mauvaise qualité. La corrosion des PMH est un problème mondial majeur, dont le secteur EAH ne s’est jusqu’à présent toujours pas saisi à sa juste mesure, et qui risque d’empêcher la réalisation de l’Objectif du Développement Durable n°6 au Burkina Faso comme dans d’autres pays. Sur les forums de discussion en ligne du Réseau pour l’Approvisionnement Rural en Eau (RWSN), les experts internationaux font notamment remonter comme principales préoccupations à ce sujet : des matériaux et des pièces composantes de qualité inadaptée, un manque de contrôle qualité, des prix anormalement bas, et des pratiques d’achat et de commande problématiques.

Une enquête sur la qualité des composants des pompes manuelles au Burkina Faso a été lancé début 2017. Des échantillons de la conduite principale montante et de la tige de la pompe ont été achetés auprès de fournisseurs à Ouagadougou, et d’autres échantillons provenaient de pompes en service ou abandonnées. Tous les échantillons ont été testés pour leur composition chimique. En 2019 des tests de composition chimique ont été réalisés sur l’ensemble de ces échantillons. L’analyse des résultats de ces tests révèle que : cinq des six colonnes d’exhaure et deux des quatre tringles ne sont pas conformes aux normes internationales de composition de l’acier inoxydable du grade indiqué. La faible teneur en nickel de ces échantillons signifie notamment que les pièces analysées ont en réalité une résistance à la corrosion moindre que celle qu’elles devraient avoir si elles étaient effectivement du grade indiqué.

Les 13 pièces composantes qui ont été testées dans le cadre de cette étude forment un trop petit échantillon pour s’avérer statistiquement représentatives de la situation du Burkina Faso dans son ensemble.  Cet échantillon corrobore toutefois les inquiétudes du Gouvernement et des foreurs. Il y a quelque chose qui ne va pas avec certains composants disponibles sur le marché, malgré le fait qu’ils soient vendus comme étant de l’acier inoxydable. L’ampleur du problème reste inconnue à ce stade au Burkina Faso ou dans d’autres pays. Comme le montre ce rapport publié par la Fondation Skat, le constat est celui d’un échec du « marché » à fournir systématiquement des matériaux de haute qualité. Afin de rectifier cette situation, il est nécessaire de trouver des solutions à la fois au sein des pays d’importation, comme le Burkina Faso, et au niveau international.

Cette étude rapide a révélé pour le Burkina Faso et au-delà une série d’enjeux interconnectés:

  1. Il est nécessaire de poursuivre les recherches sur l’utilisation des pièces composantes en acier inoxydable afin d’éviter la corrosion des pièces de PMH immergées dans des eaux souterraines agressives.
  2. La norme indienne pour les modèles India Mark II et III comprend quelques erreurs, et aucune option n’est proposée pour les cas d’eaux souterraines agressives. Les normes internationales (notamment celles publiées par SKAT/ Le Réseau pour l’Approvisionnmenet Rural en Eau-RWSN) portant sur les matériaux des pièces de PMH adaptés aux eaux souterraines agressives pourraient être améliorées.
  3. De nombreuses entreprises en Inde vendent des PMH et des pièces de modèles India Mark II et III. Les prix de vente pratiqués par certaines de ces entreprises sont si bas qu’il semble impossible que la qualité de ces pompes et pièces soit conforme aux normes internationales.
  4. Il n’existe aucun organisme international chargé de contrôler systématiquement la qualité des matériaux de PMH, et le rôle et l’activité du Bureau de Normalisation International à ce sujet ne sont pas clairs ni évidents.
  5. Lorsque les PMH sont achetées dans le pays où elles doivent être installées, la longue chaîne d’approvisionnement (souvent anonyme de surcroît du fait de la multiplicité des intermédiaires) fait qu’il n’existe pas ou peu de lien entre les fabricants (situés majoritairement en Inde) et les installateurs des PMH en question. De plus, l’absence de compilation systématique des problèmes rencontrés préalablement signifie que les agences, les entreprises et les ménages s’engagent dans l’installation de PMH sans saisir l’ampleur de ces soucis de qualité et ne s’en rendent compte que trop tard.
  6. De nombreuses PMH utilisées en Afrique sont importées d’Inde (et visiblement du Nigéria également), donc les efforts menés pour résoudre cet enjeu de garantie de qualité doivent absolument inclure l’Inde ainsi que plusieurs pays africains.
  7. L’intérêt des financeurs pour l’équipement des PMH est probablement actuellement au plus bas depuis 30 ans, il s’avère donc très difficile de mobiliser à grande échelle pour développer un processus de certification internationale ou financer davantage de recherches à ce sujet. Une telle initiative nécessiterait d’une part des investissements supplémentaires et d’autre part des engagements de long terme de la part des principales agences et des gouvernements qui financent et mettent en œuvre des programmes d’installation et d’entretien de PMH.

Nous espérons que cette courte étude attirera l’attention des gouvernements, des organismes de recherche et des agences internationales d’aide au développement et les incitera à travailler sur la résolution des problèmes pressants que sont la corrosion et la mauvaise qualité des pièces composantes des PMH. Si rien n’est fait la communauté mondiale de l’approvisionnement en eau, par négligence ou désintérêt, prive de fait les populations rurales du Burkina Faso et d’ailleurs des bénéfices d’un approvisionnement en eau élémentaire et fiable.

L’étude complète peut être téléchargée ici : Qualité et corrosion des pièces composantes des Pompes à Motricité Humaine au Burkina Faso et au-delà (anglais et français)

Crédit photo: Colonnes montantes corrodées photographiées au Burkina Faso dans le cadre de l’audit d’équipements d’approvisionnement en eau in situ. (Kerstin Danert)

 

 

Handpump corrosion and material quality: A challenge for Burkina Faso and globally

In Burkina Faso, concerns have been raised regarding the high number of handpump boreholes that have failed, or need to be rehabilitated within a relatively short time of their initial construction. Physical audits of handpump boreholes in 2013 and 2014 raise concerns over water quality, inappropriate handpump for deep water and non-conformant pumps. In more than one third of cases, the handpump boreholes will function poorly, or cease to function completely within a few years. It is estimated that investments of between FCFA 0.6 billion (€0.9 million) and FCFA 2.9 billion (€4.5 million) per year are lost due to the installation of poor quality handpumps and other aspects of the construction. In one year, over 130,000 people were provided a water supply service that is likely to break down within a few years.

Despite knowledge of handpump corrosion for over 30 years, it remains a problem in Burkina Faso, as governments and aid agencies have continued to install pumps manufactured with unsuitable materials, leading to high maintenance costs, pump failure and rejection of water sources due to poor water quality. Handpump corrosion is a major global problem which the WASH sector has so far, systemically failed to address, and which will impede the realisation of Sustainable Development Goal 6. Concerns cited by experts from a range of countries on the Rural Water Supply Network (RWSN) online discussion platforms include the following: inadequate quality of materials and components, lack of quality control, unrealistic (low) prices and problematic purchasing practices.

A renewed call to investigate the quality of handpump components in Burkina Faso was raised in early 2017. Samples of the rising main and pump rod were purchased from suppliers in Ouagadougou, and additional samples were from pumps in use or abandoned. All samples were tested for their chemical composition. Analysis showed that of the samples, five of six riser pipes, and two of four pump rods did not conform to international standards for the composition of stainless steel of the specified grade. In particular, the low nickel content means that the components have less corrosion resistance than they would if they were of the specified grade.

The small sample size of 13 components tested in this study is not a statistically representative of the situation in Burkina Faso as a whole but it verifies concerns raised by the Government and drillers themselves. Something is not right with some components available on the market, despite the fact that they are being sold as stainless steel. What we do not know is the extent of the problem, in Burkina Faso, or other countries. What is being witnessed, as documented in the new study published by Skat Foundation, is a failure of “the market” to guarantee high quality materials. Addressing this failure requires solutions from within importing countries, such as Burkina Faso, but also internationally.

This short study has shed light on a number of interconnected issues for Burkina Faso and beyond including:

  1. There is no international body systematically controlling handpump material quality.
  2. The need for further research on the use of stainless steel components to prevent the corrosion in aggressive groundwater is needed.
  3. Many of the handpumps used in Africa are imported from India (and apparently Nigeria too). There is often no connection between manufacture (primarily in India) and installation of the pump (in African countries). Agencies, companies or households installing handpumps are not aware of the extent, and scale of quality problems until it is too late.
  4. Donor interest in handpump hardware is arguably at its lowest in 30 years, and so galvanising interest to develop an international certification process or fund research is extremely difficult. Such an initiative would require not only investment, but also long-term commitment from the large agencies and governments that fund and implement programmes installing handpumps and their maintenance.

It is hoped that this short study will trigger interest by governments, and by research organisations, and international development agencies to explore ways to solve the problems of corrosion and poor quality handpump components. If this is not done, by inadvertent neglect, the global water supply community is arguably preventing rural populations in Burkina Faso and beyond from the benefits of a reliable, basic drinking water supply.

The full study is available for download here: Concerns about corrosion and the quality of handpump components in Burkina Faso and beyond (English and French).

Photo credit: Corroded rising mains being photographed as part of a physical audit of water facilitiesin Burkina Faso (Kerstin Danert).