| Jal-TARA Water Filter- A Green Technology M ost of the water-related health problems in the world are a result of bacterial contamination. Water-borne diseases are mainly prevalent in semi-urban rural areas due to a dearth of proper sanitation facilities compounded with a lack of access to health care facilities. Water-borne diseases causing major public health concern include typhoid, caused by Salmonella typhi, and cholera, from Vibrio chlorae. The economic burden due to morbidity and mortality from these diseases is staggering and some of these old and newly identified diseases still present a grim situation in India, often in epidemic proportions.Apart from biological and physical contamination, turbidity is another area of concern, especially in rural community water supply systems. High erosion in streams, less stream flow depth, loose sandy aquifers are some of the primary causes for turbid waters. Therefore, there is an urgent need for cost effective, low to no carbon, maintenance free community level water treatment systems. Chlorination, reverse osmosis, UV treatment, Ozonation and resin treatment are commonly practiced techniques in eliminating biological contamination and turbidity. However, none of these systems is completely reliable; neither are they carbon neutral and cost effective for community water supply systems. Of all these techniques, the sand filtration technique offers a chemical free, low carbon, reliable and economical treatment.  Sand filters commonly used for water treatment are of two types - slow sand (2 to 6m3/m2/day) and rapid sand (100 to 150 m3/m2/day) filters. Though there are many other ways of treating water, no single process is as effective in simultaneously improving microbiological and physio chemical qualities of water as the slow sand filtration technique. It is for this reason that slow sand filters are popular in developing countries, where land and labour constraints are not pressing, and the ease of operation, maintenance and cost are more important. Development Alternatives (DA) developed a slow sand filter (Jal-TARA Filter) for community usage to prevent the incidence of water-borne diseases. DA is working in the area of environment management, research, development and dissemination of appropriate technologies, and institutional systems aimed at sustainable development. Jal-TARA Filter The Jal-TARA water treatment system is a revolutionary approach employing the technique of slow sand filtration. This ensures a simultaneous bacteriological, chemical and physical improvement in the water quality comparable to the natural percolation of water through underground strata. Jal-TARA filter is standardised in 1000-litre water tanks with the output water supply of 2500-3000 litres per day. The filter contains specialised media of different sizes. The system is provided with a synthetic fabric filter designed with an advanced technique of fabric protection. It can be fed under gravity flow or through conventional pumps or operated by solar photo-voltaic cells. It is replication of natural water seepage as in ground aquifers. However, the media here plays an important role in the filter’s efficiency. Large and fine particles of suspended matter are deposited on the surface of the filter bed by the action of mechanical straining and sedimentation, respectively. The colloidal and dissolved impurities are removed by adsorption, whilst the organic matter is converted into organic salts via purification mechanics. The filtered water is collected at the bottom through a pipe system. Most microbiological action takes place in the Schmutzdecke (Bio-film) formed in the fabric filter at the top of the filter and the top of the sand bed. Jal-TARA filter system is quite durable and has a relatively long life (approximately 15 years). The Jal-TARA water treatment system is capable of removing Faecal Coliform and Streptococci with an efficiency of 99 to 99.9%. The system removes pathogenic bacteria that cause cholera, typhoid, dysentery, amoebic dysentery, diarrhea, giardia enteritis, hepatitis, etc. The Jal-TARA water treatment system has certain salient features. • It can provide a minimum of 2500-3000 liters per day of safe drinking water to 500 people. Being modular, a combination of units can be used to service as many people as required • The system is capable of removing bacteria and turbidity with an efficiency up to 99.9% • The low cost maintenance of this filter requires neither chemicals nor power • It is easy to install at any site in rural, urban, semi-urban and remote areas • The maintenance does not require skilled labour q M Manoj Kumar
|