Assam researchers invent low-cost technology to remove arsenic and iron from water

Researchers from Assam have invented a simple technology that together removes arsenic and iron from contaminated water at less than one paisa per litre.
The technique has recently been granted an Indian patent.
Christened ‘Arsiron Nilogon’, the filtration method uses three easily available low-cost chemicals to eliminate arsenic and iron.
The set up is simple. All it requires is two containers for two stages of the process. One for the chemical action on the contaminated water and the other for sand and gravel to extract clean water.
The capacity of the set-up can be customised according to community or household requirements.
“The word ‘arsiron’ was derived from arsenic and iron. ‘Nilogon’ is the Assamese equivalent of ‘removal’ in English. The recurring cost of the chemicals is less than Re 1 for 100 litres of water (less than 1 paisa per litre). The capital cost is the cost of the two containers, two plastic taps plus some sand and gravel,” Robin Kumar Dutta, professor, department of chemical sciences, Tezpur University, told IANS.
Besides Dutta, S Bordoloi, A J Bora, S Nath and Sweety Gogoi were involved in the development of the innovative technology.
In Arsiron Nilogon, specific quantities of baking soda, potassium permanganate and ferric chloride are added successively to a container and stirred mildly after each addition. This is followed by filtration using a sand-gravel filter, explained Dutta.
“Arsiron Nilogon removes iron too, if present along with arsenic, by adding potassium permanganate until the water turns purple from the chemical,” he said.
Currently, the procedure is being used by one Public Health Engineering Department water supply scheme, about 75 schools and several hundred households in Assam.
High level of arsenic contamination in almost entire northeastern states of India and in the plains along both the banks of the Brahmaputra in Assam came to light in 2004.
Arsenic above 50 mg per litre has been detected in groundwater in 23 out of 27 districts in Assam, six out of 13 districts in Arunachal Pradesh and two out of eight districts in Nagaland.