Strategies for water purification and the removal of heavy metals

Water was once considered an abundant, almost unlimited resource. But nowadays, population growth, drought and shortages are straining our finite water supplies. Furthermore, water quality and quantity concerns are one of the largest environmental issue facing the world in the 21st century.

Developing strategies for the purification of water is now a global issue that demands the attention of the science and engineering communities. Despite the urgency for the development and optimization of effective water purification techniques, this area is lacking in any detailed mathematical analysis, with current approaches heavily reliant on experimental observations and empirical ideas. For such a pressing global issue, the necessity for the development of mathematical models to optimize these processes is clear, with the results of such analysis leading to new, experimentally testable hypotheses and approaches.

We are currently working on a large-scale initiative to remove arsenic from water, in collaboration with researchers at IIT Kharagpur. This has been termed the largest mass poisoning of a population in history by the World Health Organisation (WHO) and has arisen due to human activity, principally agriculture, which has resulted in natural arsenic embedded in the rocks being released into the hydro-geological layers. The resulting contamination propagates upward into the food chain and disrupts the ecological balance. A solution to this problem involves the use of naturally occurring laterite soil, whose iron-rich composition adsorbs arsenic from the water (rather like a Brita carbon filter purifies your tap water). Our task is to understand how we can best use the laterite soil to maximize the rate at which clean water can be produced, and maximize the lifetime of the filter. We use a combination of mathematical modelling, asymptotic analysis, and computational fluid dynamics in Oxford, with experiments conducted on samples and real water by our collaborators in IIT Kharagpur.

filter2 filter1

The typical filter set-up and a computational fluid dynamics simulation of the filtration process.




water_team

Our water research team. Left panel (left to right) The IIT Kharagpur team: Mrinmoy Mondal, Professor Sirshendu De, Dr Raka Mondal and Krishnasri Kurada. Right panel (left to right) the Oxford team: Dr Sourav Mondal, Dr Ian Griffiths, Dr Raka Mondal.




To find out more about this project click on the links below.

Unifying scientific disciplines to solve emerging membrane-filtration challenges
Oxford Water, 10 April 2017.

Using mathematics to realise the potential of a novel soil-based filter
ECMI Node, 19 October 2016.

Oxford mathematicians in Indian arsenic collaboration
Oxford Water, 1 August 2016.

How mathematics can help to solve the current water crisis
ECMI Node, 26 October 2015.