Evaluating the technical performance and social acceptability of keg-shaped ceramic water filters in Northern Ghana

Abstract

The Kosim Water Keg (KWK) is a new ceramic water filter designed have faster filtration rates and integrate better with consumers' water habits. The design seals together two ceramic pot filters (CPFs) to form a keg shape. The keg is submerged in raw water stored in any water vessel, and water is cleaned as it filters into the keg interior, and a siphon extracts the filtered water. The purpose of this thesis is to construct prototype KWKs and test them for bacterial removal, turbidity removal, filtration rate, and siphoning rate. A preliminary consumer study is also included. Eight KWKs were constructed and tested in Tamale, Ghana in January 2011. From January 18 th to 2 5 th, the KWKs were tested using dugout water, a common surface water source in Northern Ghana. The KWKs constructed from Ceramica Tamakloe (CT) filters removed 91.9% of total coliforms and 96.0% of E. coli colonies. The control CT CPFs removed 98.5% of total coliforms and 99.4% of E. coli colonies. KWK turbidity removal averaged 58%, which was lower than the 78% removal achieved by the CPFs. Filtration rates for the KWKs were 9 to 11 liters in the first hour compared to 2 to 3 liters for the CPFs. Water siphons out of the KWKs at 0.59 liters per minute for the first 3 liters, whereas the CPF's spigot averaged 1.42 liters per minute for the first three liters. Five households tried KWKs in their homes, and responses were positive, with households particularly liking that the KWK provided clean water, kept filtered water cool, and worked inside their existing water vessels. They disliked the slow speed of the siphon mechanism. The KWK is a promising product that merits further research. Longer term testing should 1) evaluate product durability; 2) develop a filter cleaning regime; and 3) conduct a more thorough household study. The existing construction design works, but further improvements could be made to the sealant method, the siphon removal mechanism, and the restraint system used to install the KWK.