Solving Grassroots - level problems

Solving Grassroots - level problems

5:02 AM, 12th December 2018
Dr. Robin Kumar Dutta, Professor, Department of Chemical Sciences, Tezpur University in Assam, India.
Dr. Robin Kumar Dutta, Professor, Department of Chemical Sciences, Tezpur University in Assam, India.

In an interview, Dr. Robin Kumar Dutta, Professor, Department of Chemical Sciences, Tezpur University in Assam, India, with Chemical Today Magazine brings a ray of hope to millions of people affected by arsenic contaminated water by developing a low-cost filter to remove arsenic & iron from drinking water.

Widespread calamities of arsenic contaminated drinking water in India.

Arsenic is a toxic chemical element, which is present in some groundwater, usually in the forms of arsenite and arsenate. Chronic arsenic poisoning through contamination of drinking water causes several health problems including cancer which is affecting a large population of India specially in the floodplains of the Ganges and the Brahmaputra. Crores of people in Assam, West Bengal and Bihar have been affected by groundwater arsenic. Other major arsenic affected states are UP and Punjab. Arsenic has also been detected in groundwater of some other states like Arunachal Pradesh, Tripura, Manipur, Nagaland, Jammu and Kashmir, etc.

A very high rate of occurrence of cancer in these states is suspected to be linked to arsenic. While drinking of water having arsenic concentration as low as 0.017 ppb or mg/L (parts per billion or microgram per liter) is reported to cause cancer, the WHO and BIS (Bureau of Indian Standards) recommend a maximum of 10 ppb because of difficulty in detecting and removing arsenic below that. Arsenic can affect and develop cancer in any tissue or organ. This is justified by the fact that arsenic replaces thiol groups in enzymes, which control all processes within our body. Arsenic also replaces phosphate groups in ATP depriving muscles of energy.

Chronic arsenic poisoning may lead to bronchitis, diabetes, bone marrow depression, high blood pressure, cardiovascular dieses, and enlargement of liver, kidney and spleen. Other common symptoms of arsenicosis are erosion of nails, white spots on skin (vitiligo), darkening of skin (melanosis), hardening of skins into nodules (Keratosis), swelling of hands and feet and dark spots on chest, back, limbs or gums, etc., which are prevalent in the affected areas of Assam, West Bengal and Bihar.

Developing low-cost filter to remove arsenic and iron from drinking water.

We have developed a very low-cost method, ArsironNilogon, which can remove both arsenic and iron simultaneously. Arsiron stands for Arsenic and iron while Nilogon means removal in Assamese. The clue for removal of arsenic and iron was taken from the nature. The presence or absence of arsenic and iron in groundwater depends on the pH and Eh (a measure of availability of oxygen) of water, and presence of adsorbent minerals in aquifers (sandy layers where water resides underground). An oxidizing and mild alkaline condition of the aquifer favors absence of dissolved arsenic and iron in the water. We create exactly the same condition in the water, taken in a container, for removing arsenic by successive additions of three common chemicals: cooking soda (sodium bicarbonate) forpH conditioning; potassium permanganate for supplying oxygen and ferric chloride for providing iron oxide adsorbents of arsenic. Any dissolved ferrous iron is also oxidized to insoluble ferric iron oxides. Manganese dioxide formed under such condition catalyzes oxidation of difficult-to-remove arsenite form of arsenic to easy-to-remove arsenate form, a rather slow reaction otherwise. The resulting arsenate ions are adsorbed by the coagulates of iron oxides and also by solid manganese dioxide and settle down.

Performance of water treatment methods sometimes depend on local conditions. We are addressing this issue and further simplification of the method. We have recently found that ArsironNilogon also removes heavy metals like manganese, lead, nickel, chromium, copper, etc., very well along with arsenic and iron.

Technology and process involved in developing the low-cost filter.

For making an ArsironNilogon filter we need two containers, preferably plastic: one for treatment of water and the other as a sand-gravel filter. The sizes can be as per requirement of water.

The doses of the chemicals are: 0.1 gram of cooking soda, 0.5 milligram of potassium permanganate and 25 milligram ferric chloride per liter of water containing only arsenic and no iron. For 20 liters, the doses are: 2 gram of cooking soda, 6 drops of 5% potassium permanganate and 2 milliliters of 25% ferric chloride.

More potassium permanganate has to be added until a purple color persists in the water if iron is also present in the water or if the arsenic concentration is very high. After dosing the water needs about 2 hours for the coagulates to settle down along with adsorbed arsenic. The supernatant water is filtered through the sand-gravel filter or any other filter to get arsenic-free water. 

The sludge can be collected weekly or so in a small sand filter made of any ordinary container. The quantity of collected solid sludge is only about 0.5 gram from 20 litres of water. The sludge very well passes the TCLP test prescribed for arsenic by US-EPA for disposal at landfill and can be buried safely so that it cannot contaminate water or crops. The capital cost of a household filter of 20liter capacity is about INR 350 while the recurring cost is about INR 0.01 per liter. We have got an Indian patent and published some research papers on the method. It has also been technically evaluated by a third-party.

As per our research, the ArsironNilogon can remove arsenic from groundwater from any initial concentration to below 2 ppb or undetectable level. It can remove iron from any initial concentration to below 0.1 ppm or mg/L.

Comparing current method with other conventional methods.

We started with a scientific study of an indigenous method. When I was a child, I saw how my father used ash and charcoal with sand filter for removing iron from water. We kept on building up on that with more clues from nature and available literature and finally came up with ArsironNilogon.

Our method removes arsenic very efficiently and consistently to undetectable level at the minimum cost without leaving any residuals and produces a miniscule benign solid sludge. The filter can be homemade using easily available materials at the minimum cost and operated by a layman without needing electricity or maintenance.

Among other available filters and technologies, reverse osmosis (RO) rejects 60-85 percent water as liquid sludge in addition to depriving the users of essential minerals of water. The filter and maintenance cost high in addition to needing electricity. Filters using nanometarial and iron ore adsorbents produce large quantity of toxic liquid sludge during regeneration of the media and needs periodic replacement in addition to their high capital and maintenance cost.

ArsironNilogon needs 2-3 min for manual dosing for every batch of use. But it enables rural people in acquiring drinking water as before without being forced to buy it.

Taking ArsironNilogon to every house through product promotion & distribution.

People make ArsironNilogon filters themselves at home without looking for any support from Government. The recipe is as simple as making a cup of tea. With INR Rupee 1, they can purify 100 liters of water, enough for drinking for 5 days by a small family. We are only taking the message to the people through workshops and trainings with the help of a volunteers and NGO’s. It is gaining popularity in Assam and also reaching out to UP. Teachers of schools, colleges and some universities are also associated with us. The work has been supported by the Department of Science and Technology and some more Government agencies, NGOs and individuals.

Challenges faced in the research.

Aligning research with the society is not easy. In our set up, the peers want short term results and impact (factor). The experts in funding agencies, trained in conventional academic or corporate oriented research, may not have confidence on you and you may need to fund your research yourself at some crucial points of time. But it’s thrilling to face such challenges. We are trying hard to make ferric chloride available in rural markets but hope to be successful soon as the demand is rising. We face a peculiar situation during popularization of the method. The villagers take everyone approaching them as corrupt due to their long bitter experience. It often takes time to convince them and makes me feel stronger without government fund.

Patent for the low-cost filter.

The Indian Patent (No. 280737) on the method was granted in 2017. However, we have no commercial interest and have humbly turned down some proposals for commercialization. The technology is free to all for using.

Plans for future research.

We have developed another do-it-yourself technology for excess fluoride removal and got it patent. With a clue drawn from the way excess fluoride affects human, this method, Fluoride Nilogon, uses easily available low-cost crushed limestone with a tiny amount of edible phosphoric acid. It can remove fluoride from any initial level to undetectable. Fluoride Nilogon filters have been giving the consistent 0.7 ppm effluent fluoride right from the first batches for over 4500 batches or over five years with the same limestone bed without needing any maintenance. Capital cost for a home-made household filter is about INR 600 and the recurring cost is mere INR 0.005 per liter. Fluoride Nilogon is gaining popularity in Assam and Rajasthan.

However, limestones of some sources are found to be unsuitable. We are addressing this issue. We are working on scientific study and restoration of Sancipat manuscripts. Sancipat and Mahi were popular unique writing base and herbal ink of medieval Assam not found anywhere else in the world. We are also working on restoration of archaeological woodcarvings in traditional way. Recently, I have initiated a work on resource-oriented sanitation.

Advice for young researchers.

India’s grassroot problems have to be solved by Indians. Look for clues from the nature and try in a way as close as possible to the macroscopic real field conditions straight way. Ignore short-term gains and be prepared to face hardship. You can fight social evils side by side by blending science with humanity. There are ample scopes to strengthen cottage industries and small farming, and in resource-oriented rural waste management.

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