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Global praise for IIT-ians' design on waste disposal

Last updated on: July 22, 2003 16:38 IST

Two Indian Institute of Technology-Madras students -- Abhishek Jain and Suman Dutta -- have received an honourable mention from the United States-based Health Care Without Harm for designing a medical waste disposal system.

The 2 IIT-ians innovative design has bagged them the commendation in an international contest conducted by HCWH for developing non-burn technologies to dispose the medical waste.

Dutta is a final year Integrated M Tech student, while Jain completed his B Tech course and now works with Bharat Heavy Electricals Ltd.

HCWH, a global forum of 350 organisations spread across 38 countries, in its campaign for environmentally responsible health care, had conducted a global search, inviting new healthy environmental designs from all over the world.

The theme of the contest was to develop a process other than incineration.

The designs had to be low-cost, energy-saving, simple, made of locally available materials, and capable of being replicated in rural areas in the developing countries around the world.

Innovative designs were received from students, researchers, and medical personnel in 38 nations.

The first three prizes went to the teams from Australia, the United Kingdom and the United States.

Announcing the winners, Gary Cohen, director, HCWH, said: "These technologies provide a solution to the problem faced by many poor rural communities, which are burning medical waste and polluting the air with dioxin, mercury and other toxins because they lack access to affordable alternative technologies that are available in the industrialised countries."

It was by sheer accident that Jain and Dutta saw the pamphlet calling for innovative project entries by HCWH.

"We found the theme of the contest quite exciting," Dutta recollects.

With guidance from Professor Swaminathan of the department of chemical engineering at the IIT, and 'lots of inputs' from their friends, the two designed a model that can be simply termed as a mix of a mixer-grinder used in the kitchen and a washing machine that works on the hydroclave principle.

Hydroclave is a commercial system developed and sold by Canada's Hydroclave Systems Corporation. The hydroclave is a double-walled (jacketed) cylindrical, pressurised vessel, horizontally mounted, and with either two doors or a single door for loading and unloading. Steam is introduced in the vessel jacket allowing heat to be transmitted to the waste, which in turn produces steam.

"Hydroclave is a very good method to treat medical waste, and it causes minimal pollution. But the existing hydroclave systems have lots of defects and they are not so simple. More than that, prices are also high," Dutta says.

The waste disposal system works in three stages; the first being collection of waste and then segregation, treatment and disposal. The medical waste is first segregated into metallic waste and 'sharps,' glass waste, plastics and biodegradable items like cloth, pathological waste, paper, cotton, et cetera.

Hospital staff could sort it into separate bins at the time of collection itself. Sharp metal pieces like needles are destroyed by simple shearing gear, cutting them up into small harmless pieces.

The students designed a double-walled, stand-mountable and top-loading cylindrical pressurised vessel that works on the hydroclave principle. Each type of waste has to be loaded in a separate batch.

A motor driven shaft is fitted to the vessel, attached to powerful shredding and crushing blades. These reduce the size and volume of the waste. The blades are designed in such a way that they act as a shredder with sharp edges (for biological waste) when rotated in one direction, and as a crusher (for glass) in the other. The direction of rotation is chosen depending on the type of waste being treated.

Water in the jacket is boiled using a heating coil, raising the temperature of the waste which then generates its own steam.

For non-moist waste, a little water is added. The vessel is pressurised and the superheated steam disinfects the waste at the same time, as it is being shredded or crushed into small pieces.

The liquid components are steamed out of the vessel, re-condensed and drained out. The remaining waste is taken out after reducing the pressure and disposed of as solid waste. It can also be recycled.

"We knew our design was good, but what we designed was based on a survey of the hospitals and their surrounding areas in Chennai. We found that the situation is miserable in our cities too. So, the design was made with our city hospitals in mind. That put us in a quandary because the contest specifically mentioned that the design has to be applicable in the rural areas. Otherwise, we knew that our design was simple, flexible, cost effective and can be easily fabricated with locally available materials," Dutta says.

While their innovative design can be built using local materials and operated with little or no electricity and do not require highly skilled labour, the prize winning designs used no electricity at all. They used only solar power.

That might have tilted the prize in their favour, Swaminathan feels.

"When we designed, what we had in mind was the fact that all hospitals would have electrical power supply," he adds.

The total cost of a system for a 10-bed hospital is estimated to be around Rs 50,000, which is applicable to a city like Chennai and it may come down when applied to the rural areas.

Though the intellectual property right lies with HCWH, Swaminathan does not see any problem in supplying the design to hospitals in India where disposal of medical waste is a major problem. A private firm has already approached him to commercialise the design.

"As the organisers want to encourage alternative methods of incineration and spread the message throughout the world, I don't see any problem in commercailsing the design. But we will first have to check with them," he says.

The disposal system has been built only on a lab-scale. Now, Swaminathan and Dutta want to fabricate the machine as early as possible on an industrial scale and first test it at the IIT hospital itself before giving it out to others.

"I am first of all curious to know how effective it practically is. Theoretically, it is effective. First, I want to fabricate the equipment in our workshop and then test it from the waste from our own hospital," Dutta says.

They hope to complete the fabrication and further trials by the end of this year.

Shobha Warrier in Chennai