The real magic beans

Drumstick seeds can clarify water up to 99.5 per cent

By Bharat Lal Seth
Published: Saturday 15 May 2010

the drumstick tree grows in any kind of soil and requires very little care. People have many uses for the flowers, beans and twigs of the Moringa oleifera, or the horseradish tree as it is also referred to. The beans, in fact, are almost magical. They may not lead to a hen that lays golden eggs like the magical beans did for Jack in the fairy tale but they can be used to extract oil, provide nutrition when tossed into culinary preparations and prepare medicines. Quite recently, Moringa attracted the fancies of the research community as the seeds also have an inherent ability to purify water; the dried beans when ground to a powder work as natural flocculation agents.

Flocculation is the first step in water purification and the plant’s seeds provide an alternative to the commonly used alum salts, iron salts and synthetic polymers. These chemicals harm both environment and health. Alum salts have been linked to Alzheimer’s disease.

While extract of the seeds is an efficient coagulating agent, it is not clear how the proteins work at a molecular level.

In a recent paper published in the February 2010 issue of Langmuir, researchers from Uppsala University in Sweden provided technical assistance to the University of Botswana in demonstrating how small amounts of protein from these seeds bind with the impurities which include both micro-organisms and other particles. The seeds have been part of Botswana’s traditional method of water purification for years. The bound particles then form larger particles (flocs) and settle down. This means the drumstick seeds can also reduce bacterial count.

“Understanding the mechanism of flocculation is crucial to the search and possible use of other natural proteins in similar applications,” wrote the authors. “For this reason we have been looking at the amount of material and structure of the seed protein that bind to mineral surfaces,” said Adrian Rennie, one of the researchers and professor at the department of physics and astronomy at Uppsala University.

Inducted into the hall of research

The tree is native to India and there is interest in locally available, alternative means to provide clean, safe drinking water. The Department of Drinking Water Supply in India compiled a two-volume compendium of rural water supply and sanitation research projects.

One of the sanctioned studies tested the efficacy of drumstick seeds as a purification agent in villages of Tamil Nadu between 1999 and 2002. Conducted by Coimbatore’s Avinashilingam Institute for Home Science and Higher Education for Women, three villages along the river Bhavani were selected as they were drinking the river’s low quality water.

“Drumstick seed powder significantly reduced the water’s turbidity and bacterial count,” said G P Jayanthi, lead scientist for the Coimbatore study. But it is not the complete solution, she warned. This is in tune with an online protocol iterating drumstick seed usage cannot guarantee potable water and additional treatment is recommended.

In February 2010 the use of drumstick seeds was inducted into the C urrent Protocols in Microbiology which is the largest collection of online research techniques with over 11,500 protocols for scientists worldwide. It is recommended for water treatment where rural people living in poverty have little choice but to drink contaminated water. According to the paper the water treatment method is an effective clarification agent; it reduces turbidity of a fluid 80 per cent to 99.5 per cent accompanied by above 90 per cent bacterial reduction. The paper also issued a support protocol: village jar tests must be conducted with seed powder in 100, 200 and 400 milligrammes per litre of water. The jar should be stirred vigorously for a minute, followed by a gentle stirring. The sample is allowed to settle for 60 minutes. The lowest and best clarification dose is chosen by the village health workers.

There are numerous villages in India such as those along the Bhavani river which have no safe source of drinking water. Protocols on the use of drumstick seeds must be disseminated in such areas, said Jayanthi. It has been eight years since her team completed the study but there has been no follow-up owing to lack of funds.

The government is not enthused. “We do not formally approve of the technology. It has been compiled as an available option,” said D Rajasekhar, deputy advisor in the drinking water supply department. “It is left to the state to identify them as viable low-cost alternatives,” he added.

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