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Coconut to Take Care of Waste Water
|by V. K. Joshi (Bijji)|
An old belief says, 'the amount of wastes produced is an indication of the level of cultural development and the aesthetic sense of people'. Go to any major city of India and you find the heaps of waste. Majority of the people take it as a routine or rather destiny. The solid waste is visible. The liquid waste on the other hand flushed down the toilets travels through sewage pipes to major sewers which invariably end up in a river. The condition of the rivers is well known. Earlier, during a train journey through western U.P. one could tell from the whiff of sulphurous odor in the air that a sugar mill is approaching. As the track went past the mill the stench became almost unbearable. Now those nose covering journeys are a thing of the past, because often the foul smelling, untreated sugar mill waste Is piped through sub-surface to a nearby drain or stream.
The problem of liquid waste is still more hazardous as it pollutes not only the surface water bodies but also quite a part of obnoxious matter travels through the pores of the soil to reach the ground water reservoirs. At this juncture it is pertinent to reproduce a table depicting per capita waste generated in some of the important municipal areas from a book 'Saket Environmental handbook by J.N. Vyas and R. Parthasarthy (2001):
It is also worth pointing out that though in terms of population Lucknow is not dense compared to cities like Delhi and Bangalore, yet the quantum of waste generated is maximum. Lucknow is a developing Capital. Mind you the figures are of 2001. In seven years the situation has not improved but deteriorated.
Everywhere the reply of the Municipal authorities is same, 'financial crunch'. It appears as citizens we are bent upon producing more waste than the municipalities can safely dispose off with the funds available to them!
Bio-filtration is a new concept being researched by the waste water experts in India too. A. Praveen of Department of Civil Engineering in Rajiv Gandhi Institute of Technology, Kottayam, lead author of a paper in the September 2008 issue of Current Science, has described a cheap and effective bio-filtration technique which should motivate the 'poor' municipalities for a within reach treatment of waste water.
Any naturally available fibrous material rich in organic material serves the purpose of a bio-filter. The fibrous material increases the area available for effective filtration. The pollutant rich fluid as it passes through the filter medium comes in contact with the micro-organisms attached to the fibers of the filter. The micro-organisms in turn thrive on the organic molecules of the pollutants. Thus pollutant is actually food for other organisms. A sudden rush of pollutants sometimes shocks the micro-organisms devouring the nuclei and leads to a 'shock'. The waste experts use peat and bog in addition to the bio-filters to tackle the shock.
These filters use polymer fiber based filters. Which are costly. Thus, while looking for an alternative, Praveen and his co-workers zeroed down on coir, a hard and tough organic fiber extracted from the husk of coconut. It is cheap, rich in cellulose and lignin. The fibers give it a much higher specific area and wetting ability, which is essential for bacteria to remain adhered and take the onslaught of polluted effluents.
Coir is being extensively used as a geo-textile for large-scale application in checking erosion, soil-engineering and resources water management. Seeing the utility of coir geo-textiles over other natural fibers to check soil erosion and improving vegetation cover, Praveen and colleagues decided to use fiber-packed conduits to find out the impact on biodegradation of fluid waste matter as it flows through them. In order to evaluate scientifically the efficiency, they selected geo-textiles of specific weight of 0.9-1.7 kg/meter square for systematic experimentation. In their experiment the length and diameter of the pipes, packing densities of fiber filters and even the waste water to flow through them were all tailor made so as to establish the best combination for optimum results.
It was found that microbial activity increased in low density filters under lower organic loads. A continuous supply of polluted effluents affected the microbial activity in the entire length of the pipe. Thus the authors claim that coir geo-textile-packed conduits with well graded fibre density along their length would be reliable and consistent in the removal of biodegradable matter from wastewater. It was also found that in low density filters, in case the drain pipe was not used for long, the reuse did not lead to reduction in microbial activity or clogging. However, a high density filter needed to be cleaned.
The system explored by Praveen and colleagues is significant as it uses a cost effective technique and provides acceptable level of performance. In small residential drains carrying waste water from the kitchens and bathrooms to larger drains and finally to a stream and also uncontrollable discharge from industries to nearby streams, coir geo-textile based treatment can be effectively used with the help of properly designed techniques.
Yet another problem commonly found in urban drains is decaying organic matter. The problem is more acute in the urban centers of north India, where the residents invariably dump their biodegradable household waste in the drains across their residence. These drains are in reality storm water drains on both sides of the road. They are not meant to carry solid waste. Very often these drains are also used as open toilets. Therefore the drain water also carries the night soil. The problem gets compounded if the drinking water supply pipe line cutting obliquely across such drain begins to leak. During low pressure the contaminated drain water enters drinking water supply-one of the root causes of stomach ailments in India. Praveen says the problem can be tackled with the help of bio-drains, i.e. segments of the drain packed with coir-bio-filters. These filters will remove the obnoxious matter through the process of microbial action and treat the drain water to an extent that it does not remain a hazard.
Such innovative technologies are required to be used all over the country for the health of the people and the health of the rivers. It is needless to emphasize that the long range effect of treated water reaching the rivers is on marine biota as well. The day is not far when it would be possible to treat the household wastewater with the help of coir-bio-filters and recycle it. Need for recycling of water is already pressing because large tracts of country are facing the drought.
The simple coconut may finally provide us relief against so many problems!
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