VIJAYA NAMBIARSHAHANA HUSSAIN2018-05-242018-05-241993http://krishikosh.egranth.ac.in/handle/1/5810047420Water used for drinking has to be subjected tosome kind of treatment before consumption due to the presence of many undesirable impurities. One of the useful conventional methods of domestic purification of water, is to clean it through the use of domestic water filter candles. Most of the commercially marketed filters are not within the economic reach of majority of the rural population. Hence the production of cheap water filter candles using low cost, indigenous raw materials for production of filters is a necessity. This study was therefore taken up with the following objectives. l. To identify raw materials to mix with clay in the preparation of a low cost water filter candle. 2. To examine the comparative efficiency of different water filter candles. Filter candles were made with all possible combinations of coal and clay and rice bran and clay as these raw materials are inexpensive and easily available in rural areas. All the candles were tested by subjecting thewater filtering through them, to multitube dilution test. Five trials were conducted with each candle, using fresh water for each trial, to determine its efficiency. In order to compare the efficiency of newly developed candles with those already developed, a commercial water filter candle and a low cost clay—sand mix candle were selected. The filteration rate and efficiency of candles in terms of microbial quality of filtered water were studied. It was observed that the candle made with 80 percent clay and 20 per cent coal worked out better than all the other proportions tested, as it was effiCient in filtering out the bacteria that was introduced, but for a limited period only, after which the quality of the candle started deteriorating. None of the candles made with rice bran and claywere found to be effective in filtering bacteria—free water. The candle made with 60 per cent sand and 40 per cent clay was also found to be defective with several drawbacks, as such unable to filter bacteria free water for even a single trial. This is contrary to an earlier study done by Rama (1986), in which it was found that clay sand mix candle was 100 per cent efficient in the removal of bacteria. This is apparently due to the absence of a mechanised procedure in preparing the clay-sand mix candle and no standardised procedure in mixing the raw materials which may give room for human error due to which the filter in question proved inefficient. The commercial candle was found to be workingefficiently filtering cent per cent bacteria free water. It was filtering water uniformally at a desirable rate, throughout the experiment. In case of both the candles C and clay—sand mix candle, the rate of filteration was found to be gradually decreasing obviously due to the fact that the candle pores were getting clogged very easily. The study revealed that the commercial water filter candle, filters water most optimally and candle C , although efficient in trapping bacteria for three tria 5 had a life span which was limited, and therefore its use can be recommended only after further research has been done on this particular candle mix to improve its durability and efficiency.ennullThesis