Cleaning the microbe way

Even the tiniest microbes could help spruce up our foul environment when let loose on domestic waste. Researchers in Delhi are now advocating the use of this miniscule life form to solve the huge problem of urban waste. These tiny do-gooders do not just clean up the garbage but convert it into useful products

Published: Wednesday 31 January 1996

Dumping waste or wealth A CLEANER and healthier world may not be a distant dream if we, as its citizens, learn to use its resources to the maximum. For achieving this, conserving energy through means like recycling waste and bio-degradable matter would make all the difference. The department of microbiology under the School of Life Sciences, Jawaharlal Nehru University (JNU), has developed just such waste-eating microbes.

Microbes offer long-term, sustainable solutions that protect the environment apart from generating employment oppurtunities. Biomass, comprising substances like dead leaves, household vegetable and fruit wastes, and hedge trimmings could be made to decompose with the use of microorganisms which the JNLT researchers have developed.

As of now, large pockets of urban India, in particular, are submerged in rather unhygienic conditions. In capital Delhi, the disposal of the carcasses of animals at various dumping sites presents a formidable health hazard. The perenially choked open drainage system and the mounds of garbage do not seem to move the city's builders, architects, private estate agents or the Delhi Development Authority, On an average the Municipal Corporation of Delhi (MCD) lifts about 4,300 metric tonnes of the city's garbage everyday with its 430 strong fleet of trucks. But ironically, most of these trucks spew black fumes (unspent fuel containing toxic gases). All such eye sores could easily be converted into useful products were we to employ these friendly microbes.

The decomposed organic material could serve as a nutrient-rich compost. The quality of the compost so produced is far superior to the commercially available khad and chemical fertilisers. The compost also proves to be more immune to pathogenic organisms and pests (termites). For instance, straws from various agricultural crops like rice, wheat and barley could be used for mushroom cultivation. Normally fungi are used to produce certain enzymes which break down complex polymers into glucose and other simpler chemicals. However, this is time-consuming and delays the production of edible mushrooms. Instead, if waste straws could be pre-treated with microbes and then sprayed on the mushroom seeds, there could be a considerable reduction in production time. Also, more cycles of cultivation could be achieved, to enhance the cultivation of mushrooms, reaping greater profits for the cultivators.

Other industrially useful chemicals could be produced from cellulose, a major component of most organic matter. Cellulose could be reduced to simple sugars (glucose). In practice the glucose could be utilised by bacteria, both aerobic and anaerobic, for the production of biogas (methane) and densified fuel briquettes.

Agro-wastes may also be converted into a perfect substitute for wood. Available in panels, it may be ideal for all kinds of wood work replacing ply, board and wood. Tomato and potato peels could be used to make adhesives and replace synthetic fevicol and other chemical glues.

With appropriate microbial management, the organic biomass could be composted in each locality itself and can be distributed to local residents at a nominal cost. Builders and town planners should develop compost pits in each residential area.

One such programme was devised by Ajit Varma of the School of Life Sciences, JNU, in collaboration with K Chandra Of DLF Universal, Gurgaon, Haryana. The waste organic biomass was spread into compost pits and sprinkled with a mixture of specially developed microbes (bacteria and yeast). This was layered with thin films of animal dung, slurry and lime (serving as a deodarant) followed by native soils. These layers were repeated several times till the compost pits were totally covered. The required moisture content for effective microbial fermentation was maintained by the sprinkling of unfiltered ground water or waste water at regular intervals. Within 90 days, the biomass was completely composted and served as fertiliser for agricultural, horticultural and floricultural purposes.

If such a technology were to be developed on a commercial scale, even businesses could benefit from the same while contributing to environmental protection and sustainability.

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