A laboratory study of upward flow water filters for use in rural households.

Drinking water in most rural areas in developing countries is obtained mainly from surface sources which are invariably vulnerable to pollution. Water related disease such as cholera,dysentry, poliomyelites hepatitis and schistosomiasis etc. have been very frequent in these areas because of pollution. As a result water from these sources need treatment so as to make it potable and acceptable to the users as well as the project proponents. Water treatment for domestic purposes is in most cases lacking in rural areas and also it is becoming increasingly costly even for large towns and cities due to among other reasons (i) the escalating prices of both chemical s and treatment plant equipment (ii) the lack of trained personel and most importantly (ii i) both foreign exchange and capital the lack of In an attempt to find a solution to the treatment of surface waters for domestic use, a study of upward flow water filters was carried out. The filter media selected for the study included fine grained sand, coarse quartz sand, charcoal and a multilered arrangement of the above media. Five experimental filtermodels were considered; Filter A with fine sand as medium; B with charcoal ;c with fine sand; D with charcoal and coarse sand and E with fine sifted sand, charcoal and fine unsifted sand. Filters A, B, c and D were of perspex plastic pipes and E was of cement mortar. The aim of the study was to verify the efficiency of the filters with respect to turbidity removal , reduction of pathogenic organisms and their effects on the pH. Filters A and c media material scan be used as individual filtermaterials but filters D and E with turbidity removal efficiencies of 98.5% can be much better. Filters,A, B, C and D had no effects on the pH values but E increased them by an average of 10%. Feacal coliforms reduction efficiencies for A, C,D and E averaged 50% but filter B recorded an increase for most of the runs . In conclusion, (i) filters A,C,D and E can be used in household filtration of waters that are slightly polluted but not B . (i i) The untreated water tank can be used as a slow and filter so as to improve the backteria reduction afficiencies of A, C, D and E, and (iii) clay jars may be used instead of cement mortar jars to minimize the increase in pH.