Suitable types and constituent ratios for clay-pot water filters to improve the physical and bacteriological quality of drinking water

This study aimed to investigate suitable types and ratios of materials for making clay-pots, and their performance to improve the physical and bacteriological quality of drinking water. Synthetic water was prepared and used to select suitable types and ratios for clay-pot water filters. The clay-pots were prepared by combining clay with sand, coconut-shell charcoal, and rice-husk charcoal, at various ratios. The results indicated that all types and ratios could remove 100% of coliform bacteria and Escherichia coli, and were thus suitable for treating drinking water. However, for practical use, the system should have real-world application. Therefore, filtration rate/inner surface area/time was used as a criterion to determine suitable types and ratios. Different types of clay-plot water filter yielded significantly different filtration rates (p<0.01). Clay with coconut-shell charcoal generated the maximum filtration rate of 0.44 ± 0.11 mL/cm²/hr. Different ratios of clay-pot water filter did not yield significantly different filtration rates (p>0.01). A ratio with a maximal filtration rate of 60:40(0.38 ± 0.28 mL/cm²/hr) was found to be suitable. The quality of filtered water was acceptable in terms of turbidity, coliform bacteria level, and Escherichia coli, according to WHO drinking-water quality guidelines.