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In nature, the waste product of one organism is the food of another. That’s the reason why in the wild or in the non-humanized world, we find little abandoned or accumulated waste. Human organic waste, too, is largely degradable in nature.

Problems arise when heavy metals like lead, mercury, arsenic, chromium, etc., as rejects from our industrial activities, are let loose into the environment (soil, water and air) in the form of industrial effluents or there is an overburden of unutilized chemical pesticides, insecticides and fertilizers running off during rains from our farms to enter and pollute water bodies (ponds, lakes, rivers and oceans).

Petroleum products from oil spills in seas or land add a toxic burden to our natural environment. Leachates from landfills holding contaminants are another source of pollution.

On their own or in combination, these are serious health hazards and the cause of many cancers. Toxic chemicals are now increasingly originating even from our residences in the form of polluted wash water, including detergent run-off, cosmetics, plastics, paints, electronic waste and poisons from pest control measures, etc.

Frequent mixing of sewage and industrial effluents in common drains (many of which were originally stormwater drains) frustrate municipal and industrial cleaning systems like sewage treatment plants (STPs) and effluent treatment plants (ETPs), turning them ineffective as their respective technologies are not equipped for the toxic cocktail that they often receive.

But in the past few years, a technology popularly known as bioremediation has come to the rescue.

Bioremediation is to create enabling conditions in which the naturally occurring microorganism or their enzymes (bio-molecules) are encouraged to tackle toxic elements present in our environment by either consuming the latter as food or by isolating them for easy separation from the polluted soil, air or water. In the words of M. Vidali, a well-known expert, “Bioremediation is an option that offers the possibility of destroying or rendering harmless various contaminants using natural biological activity."

The 20th century saw not only an overwhelming pollution of the planet’s natural environment through runaway industrialization and an introduction all over of intensive farming practices, but also engendered way back in 1900 the first human efforts at bioremediation to treat organics derived from human or animal waste.

The later half of the century saw investigations into bioremediation of synthetic chemicals present in waste water and with rising instances of oil spills in the seas, spurred its application to hydrocarbon contamination and cleaning of petroleum in ground water. Since then, bioremediation has been tried with varying degrees of success in different parts of the world.

In India, bioremediation offers a viable option in waste water treatment, sanitization of existing landfills and cleaning of ground water.

India has traditionally used plants like grass, sedge, hemp and canna to clean waste water. Even water hyacinth, otherwise an invasive species in any lake system, is found useful in the removal of arsenic from waste water. This in modern terminology is called phyto-remediation, where some plants (estimates suggest a list in excess of 300) have the natural ability to degrade and eliminate from waste water common pollutants like metals and pesticides.

While bioremediation is catching on and additional research is adding value to its effectiveness, it would be premature to assume that mankind has found the proverbial silver bullet to end its increasing problem of environmental pollution. It is because experts cite both advantages and disadvantages.

Being a natural process is its greatest asset. Clean-up costs in comparison with other methods are much less. Residues from the process are usually products like gases (mainly carbon dioxide), water and cell biomass. It can also tackle a wide variety of contaminants and destroy them completely. It could be carried out in situ (on the site) thereby discounting costs and hassles associated with land purchase or acquisition and in preventing transportation costs and risks.

But everything has its disadvantages and bioremediation is no different. Although natural, it still remains an introduction by man of a microorganism that could prove disruptive or harmful to other organisms present in the same environment and hence, while solving one problem could result in the creation of one or more with impacts which might be long-term and could sometimes prove far more damaging than the pollution it started with.

The process being highly specific is also not universally applicable and is labour-intensive and time consuming. Lab-to-field transfers of research technologies and findings have also presented challenges and the upscaling of pilot projects have not always worked as planned. Often toxic cocktails (encountered in Indian conditions) of contaminants found together and even in varied forms (solid, liquid and gas) could prove frustrating.

Thus, clearly while there is an interesting and exciting pollution abatement option now in hand with the authorities, they would be well advised to not rush headlong into their adoption without mustering all due caution. There might also be issues of a legal nature, where an existing law might be inhibiting or a new one required.

Man, by trying to ape nature, does not become god. Let us not forget that it is nature alone that knows best its own complexities and processes.

Hence, the longer we desist from compromising natural processes like flowing rivers (with a huge capacity to self-rejuvenate), we can hope to have a healthy natural environment for us and our future generations at little or no cost to us.

Manoj Misra is convenor of Yamuna Jiye Abhiyaan, a civil society campaign for a rejuvenated Yamuna. He is also a forestry and wildlife expert who formerly served with the Indian Forest Service for 22 years.

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