Performance and cost comparison of a gravity-driven free-end membrane and other water filtration systems for household water treatment

Various types of gravity-driven membrane (GDM) systems have been developed to solve household water treatment problems. A gravity-driven free-end membrane (E-GDM) system was developed to mitigate the deposition of cake on the membrane more effectively than other commercialized GDM systems. The E-GDM system was manually operated with permeability of 12.94 and 1.75 L/m(2)/h/kPa for a kaolin suspension and a wastewater treatment plant influent sample, respectively, showing the highest average permeability and flow rate among all GDM systems. The GDM systems tested in this study met the daily minimum water requirement of a five-person family, except for a case in which wastewater treatment plant influent is filtered using a commercialized GDM system. According to permeability data from an accelerated cleaning test, the E-GDM system can be expected to guarantee 79,858 L of safe drinking water during its lifetime. The annual cost of the E-GDM system was assessed to be US$5.71 per household, which allows household water treatment in low- and middle-income countries.