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Purifying water with apple and tomato peels

30 July 2013

Ramakrishna (left) and Assoc Prof Valiyaveettil with a bottle of clean water after purification

According to a 2013 progress update on sanitation and drinking water by UNICEF and the World Health Organization, there were still 768 million people who did not use an improved source for drinking water in 2011, including 185 million who relied on surface water to meet their daily drinking needs. Among them were many rural dwellers and the poor who often missed out on improvements to drinking water and sanitation. Addressing the need for clean water, PhD student Ramakrishna Mallampati of the Department of Chemistry developed a novel purification method using apple and tomato peels for water treatment. 

Giving the context to water purification challenges, Ramakrishna explained that water pollution is caused by various pollutants such as dyes, pesticides, anions, toxic metals, bacteria and particles. To get rid of such impurities in contaminated water, several steps are required, some of which are expensive and difficult to set up. 

“The research objective is to remove all pollutants simultaneously using a single adsorbent,” said Ramakrishna whose work was supervised by Associate Professor Suresh Valiyaveettil, also from the Department of Chemistry.

On the novel use of tomato and apple peels, Ramakrishna said that they are easily available around the world through all seasons. He added: “The peels are low cost, affordable or cultivated, and easy to handle. They are also non-toxic, biodegradable and have fast adsorption. In addition, the different functional groups of the peels help to interact with a range of pollutants.”

For a rough measure, the peels from eight tomatoes can remove heavy metal ions from one litre of water in an hour. The researchers felt that this easy purification technique caters best for economically and technologically disadvantaged farmers residing in remote villages with little electricity or resources to set up a water purification plant.

Moving forward, Ramakrishna and Assoc Prof Valiyaveettil are collaborating with Singapore’s national water agency, PUB to scale-up the purification technology and effort. At the international level, they hope to work with non-governmental organisations to transfer their research findings and knowledge to benefit rural dwellers.