Development of Effective and Fast-Flow Ceramic Porous Media for Point-of-Use Water Treatment: Effect of Pore Size Distribution

Ceramic filters are widely used for sustainable point- of-use water treatment in developing countries. It has remained a great challenge, however, for ceramic filters to simultaneously achieve high flow rate and effective bacterial removal. In this work, we reported the use of recycled paper fiber (greenfiber) as combustible material for the development of effective and fast- flow ceramic filters and compared their performance to filters that were fabricated using starch and rice husk, two common combustible materials used in previous studies. The clean ceramic filters made using 15% greenfiber achieved >4 log removal of bacteria (>99.99% removal) and an equivalent flow rate of 5.9 L/h 37.5 L/m(2)-h); the filters made using 20% greenfiber exhibited a fast flow rate of 13.9 L/h (87.1 L/m(2)-h) while maintaining a log microbial removal efficiency of >2 (>99% removal of bacterial cells). The two flow rates were similar to 100% and >300% higher than the flow rates of mainline ceramic filters currently in use. The filters were characterized using mercury intrusion porosimetry, scanning electron microscopy, X-ray fluorescence analysis, and Fourier transform infrared spectroscopy. Our results suggested that the pore size distribution pattern played critical roles in the microbial removal efficiency. A mathematical framework was developed to provide a semiquantitative analysis of the relationship between filter bacterial removal efficiency and pore size distribution.