Tackling arsenic contamination in India through mathematical modelling and engineering.

Oxford mathematicians collaboration with IIT Kharagpur seeks to address one of the world’s most pressing water quality challenges.

Arsenic is a naturally occurring element found in the rocks and earth’s crust, and is among one of the most hazardous contaminants in drinking water sources. Arsenic is embedded in geological sources and enters into the water supply as the rocks are eroded by the flow of water from rivers and rainwater. Further, use of manure containing phosphate, and other agricultural activities break down different rocks and release arsenic into natural water. Consequently, if not properly managed, the level of arsenic contamination will continue to rise because of human activity and agricultural growth. At present, more than 200 million people and over 70 countries in the world are affected by arsenic contamination. The WHO has declared 10μg/L as the safe limit of arsenic in drinking water in 2000.

To address this issue it is necessary to have a water-purification technology that: (i) meets the safe drinking water criteria; (ii) requires minimal energy; (iii) offers high throughput; (iv) is easy to scale up to cater for large populations; and (v) generates minimal waste. A novel strategy that achieves all five of these criteria has recently been discovered, using readily available laterite soil. Laterite is iron-rich and is able to remove arsenic through adsorption. Raw laterite can be treated chemically to enhance the surface area and increase adsorption capacity by several factors. Refining the granular laterite to produce laterite dust increases the surface area and improves adsorption capacity even further. Filters that use this laterite soil are currently providing potable water to more than 5000 people.

However, as with any other adsorption technique, such filters have a certain lifespan, beyond which the filter media becomes saturated with contaminant and the filtrate no longer meets the safe limit for drinking water. For example, a household Brita water filter should be replaced after around two months. Thus, for the design and successful implementation of an adsorption technology, it is vital to be able to predict the long-term behaviour of the filter. Such performance is influenced by the operating configuration, specifically, the input rate of the contaminated water, the mass of the adsorbent and the contaminant concentration level. To understand and predict this warrants the need of a suitable mathematical model to understand and characterise the operation and to predict the adsorption behaviour and filtration performance. Researchers Dr Ian Griffiths, at the University of Oxford’s Mathematical Institute, Dr Raka Mondal (formerly Oxford), Dr Sourav Mondal (formerly Oxford, now IIT Kharagpur) and Professor Sirshendu De (IIT Kharagpur) recently teamed up to tackle this challenge.

Together, they derived a mathematical model that characterises arsenic removal and circumvents the need for time-consuming experiments. The model couples fluid flow in a porous medium with the convective, diffusive and adsorption dynamics of the arsenic within the water as it passes through the filter medium. Using asymptotic analysis, they reduced the model to a system that may be described by a single dimensionless parameter, which they termed the filter rating, that encapsulates the entire filter behaviour. The resulting model was validated using laboratory-scale experiments conducted at IIK Kharagpur with contaminated water from the community before being used to make predictions on the lifetime of this filter in a specified role, such as on a domestic or community scale.

In October 2017 the results of the work were presented at a workshop in IIT Kharagpur to government officials and UNICEF representatives. 40 community scale filters are now planned to be deployed in 2018. The ultimate outcome of the model analysis is the generation of a performance–lifetime relationship for field implementation that provides a protocol for ensuring the sustainable operation of such filters.

The results of this work led to an MPLS Impact Award for the contribution made to the development of a maintenance protocol for water filters, enabling cost-effective deployment in India. The researchers are now developing their ideas for the removal of other contaminants from water with an ultimate objective of providing potable water for the world.

Policy perceptions and responsibility for the water service mandate across Kenya’s 47 county governments

DPhil student Johanna Koehler explores how Kenya’s devolution process has affected water service delivery.

Improving water services is a well-rehearsed political instrument to win public support against a backdrop of a wide range of hydro-political realities in Africa.

A new article, published in Geoforum as part of Johanna Koehler’s doctoral research, presents novel insights from Kenya’s devolution and water service reform, drawing on perceptions from all 47 devolved county water ministries.

The research asked all mandated policymakers of the first devolved county governments, following the introduction of Kenya’s 2010 Constitution, this question:

“Are you responsible for universal, safe, sufficient, affordable & equitable water services?”

The question elicited a broad range of responses, shaped by a host of political, socioclimatic and spatial factors, which influence the extent to which county policymakers assume responsibility for the water service mandate.

The paper seeks to unpack specific factors that influence decision-makers’ perception of their responsibility for water service delivery in their counties. Leveraging public choice theory, the research develops and tests a sociopolitical risk model, integrating information on election margin, climate risk, urbanisation, poverty levels, water budget and citizen satisfaction, to explain variations in the policymakers’ perceptions regarding their responsibilities.

Fig. 1 | Sociopolitical risk model (Koehler, 2018)

The study reveals that county water ministries recognise increased political responsibility for the poor outside current provision areas across water quantity, quality, accessibility and non-discrimination criteria. Affordability is the most contested criterion, with only a limited number of counties accepting responsibility. High socioclimatic risks and narrow election margins are likely to boost the devolved duty-bearers’ perception of responsibility for improved water service delivery. These variable factors demonstrate the interdependence of spatial and political dimensions during Kenya’s devolution process and promote the conclusion that independent and strong regulation is critical to realising the human right to water for the great majority of Kenyans living in rural areas and facing unpredictable climate risks.

Fig. 2 | Map of Kenya showing Election Margin 2013 and Water Responsibility Index (Koehler, 2018)

The research highlights a number of key implications from Kenya that ought to be considered when formulating and implementing future policy, and which may also be relevant to other countries in sub-Saharan Africa undergoing institutional transformations in the form of decentralisation:

First, the allocation of adequate financial resources appears to be the strongest limiting factor for the recognition of responsibilities and their translation into actual water service delivery. Major investments are being made in new infrastructure development for water services. However, without a higher priority on monitoring and maintenance provision, the sustainability of this infrastructure is questionable and SDG (Sustainable Development Goal) 6.1 is unlikely to be met in the long term.

Second, the wide variance in the decision-makers’ perceived responsibility for the water service mandate needs to be addressed across the human rights criteria so that regional disparities do not grow and transformative development is sustained, especially in rural, marginalised areas. This highlights the importance of spatial concepts of central–lregional, interregional and urban-rural relations for political decision-making and the crucial role of regulation at the national level for universal coverage.

Third, it appears that a healthy level of democratic competition in the gubernatorial elections drives the water service agenda and the fulfilment of constitutional obligations. At the start of Kenya’s second term under devolution, with 47 county governments in charge of the provision of services in sectors such as water and health, this study observes that devolved duty-bearers have generally adopted a target-oriented approach towards the implementation of the constitution so as to achieve progressive realisation of the human right to water during the first phase of Kenya’s devolution process. Their perceived responsibility appears to focus on the poor in underserved areas. While inequalities remain, devolution has spurred progress towards target 6.1 of the 2030 Agenda for Sustainable Development .

Finally, responsibilities across the human rights criteria are driven by a number of political and socioclimatic factors. Countries do not respond uniformly, especially if they have a devolved system of government. Globally, the question as to whether the targets of the 2030 Agenda for Sustainable Development will be achieved begins with the acknowledgement and uptake of the mandate by duty-bearers, before actual progress can be measured, and depends on each country and its subnational institutions’ sociopolitical and geographical realities.

If you would like to learn more or cite this research, please refer to the journal article: Koehler, J. 2018. Exploring policy perceptions and responsibility of devolved decision-making for water service delivery in Kenya’s 47 county governments. Geoforum 92: 68-80.

Funding acknowledgment
Johanna Koehler is a DPhil scholar in the Smith School of Enterprise and the Environment supported by the Oxford University Clarendon Fund. This research was also supported with funding from the UK Natural Environment Research Council, the UK Economic and Social Research Council and the UK Department for International Development for the UPGro programme on ‘Groundwater Risk Management for Growth and Development’, the UK Economic and Social Research Council for the ‘Mobile payment systems to reduce rural water risks in Africa’ project, and the UK Department for International Development for the ‘REACH: Improving water security for the poor’ programme. 


How can water research have more impact?

How the Oxford-led REACH programme is working to achieve impact.

Research impact is increasingly important for academic institutions. Ideas of ‘research for research’s sake’ are fading as impact now counts for 25% of a university’s REF2021 assessment up from 20% in previous rounds.

Oxford University is leading a 7-year, DfID funded water research project called REACH to improve water security for 5 million poor people in Africa and Asia. In a problem-focused, policy-driven project such as this, it is necessary to consider what research impact is and how it can be achieved and measured.

Last week, Dr Catherine Fallon Grasham, a human geographer and postdoctoral researcher for REACH, presented at Making a Difference: an impact conference for the social sciences, held at St Anne’s College in Oxford. Stakeholder engagement emerged as a critical component of achieving research impact. There was also a shared consensus that social science has an image problem. It is too often regarded as a ‘soft science’, less rigorous and relevant than the physical sciences. Social scientists must find more convincing ways of communicating the importance of their research findings.

Research impact takes multiple forms. It is essentially about finding avenues for research to have some influence in shaping the world that we live in. Specifically for REACH, it is about identifying and engaging with decision-makers to ensure that the research is driven by local needs, embedded within existing processes of change and that there is local ownership of resulting interventions.

REACH is designed to build science-practitioner partnerships and works closely with UNICEF across Bangladesh, Ethiopia and Kenya.

“Successful relationships with partners and stakeholders, such as government bodies, private companies and NGOs, have been absolutely crucial for REACH to have impact,” said Dr Grasham.

The Rural Water Supply Network and the International Water Association are also part of the REACH consortium and have strong roles to play in disseminating research findings to their networks.

Water researchers commonly work within interdisciplinary teams and REACH works across the social and physical sciences. Understanding the socio-political processes that shape access to water is critical for finding ways to improve water security which means that there is a lot of space for social science in the project. Dr Grasham went on to say:

“We are all working together towards a common goal of improving water security for 5 million people which makes it easier for us to work across disciplines.”

Next month, Dr Grasham will be travelling to Semera in the Awash river basin, Ethiopia to engage with stakeholders about her social research on the inequality of water access and to identify the most tangible ways that REACH research can have impact.