Flowrate is used as a predictor of ceramic pot filter (CPF) disinfection effectiveness, and the relationship between flowrate and porosity has been examined in several studies. However, hydraulic conductivity, not porosity, is the constant of proportionality that describes flow through porous media. Equations have been developed to estimate the hydraulic conductivity of CPF side walls and bottom as well an effective overall hydraulic conductivity. The equations are intended to be used with falling head data that may be collected in the field. The results of flowrate testing and open porosity testing using experimental CPFs provide preliminary indication that hydraulic conductivity is a better predictor of flowrate relative to open porosity. The results of the preliminary testing suggest that the shape and orientation of open pore space may have significant impact on filter flowrates, and that filter researchers and producers may want to evaluate the material used to form the pores as well as the impact of the filter formation process on any spatial orientation of open pore space. A better understanding of hydraulic conductivity may improve the production efficiency of filter factories which could make lower cost filters available to a greater number of households in developing areas.
Keywords: ceramic pot filters, drinking water, flowrate, hydraulic conductivity, porosity