US EPA

4967189 

Journal Article 

Porosity, Flow, and Filtration Characteristics of Frustum-Shaped Ceramic Water Filters 

Yakub, I; Plappally, A; Leftwich, M; Malatesta, K; Friedman, KC; Obwoya, Sam; Nyongesa, F; Maiga, AH; Soboyejo, ABO; Logothetis, S; Soboyejo, W 

2013 

Yes 

Journal of Environmental Engineering
ISSN: 0733-9372
EISSN: 1943-7870 

139 

7 

986-994 

10.1061/(ASCE)EE.1943-7870.0000669 

WOS:000322537100008 

This paper presents the results of an experimental study of the effects of porosity on the flow rate and Escherichia coli (E. coli) filtration characteristics of porous ceramic water filters (CWFs) prepared without a coating of silver. Clay-based CWFs were fabricated by sintering composites of redart clay and fine woodchips (sawdust) in three different proportions by volume, viz: , , and . Sintering the greenware below 1,000 degrees C produced reddish colored pot of three different degrees of porosity and micro- and nanoscale pores, which are the key to efficient filtration. The porosities and pore size distribution frequencies of the sintered clay ceramics were characterized using mercury intrusion porosimetry (MIP). The porosity of the CWFs ranged from to and increased with increasing sawdust content in a linear fashion, and the pore size varied from to . The volume flow rates of water through the CWFs were investigated by measuring the cumulative amount of water flow as a function of time. The flow rate was found to increase with increasing porosity of the CWFs. The effective intrinsic permeabilities of the CWFs were then obtained from Darcy fits to the flow rate data. These were compared with values obtained using the Katz-Thompson method. Both approaches gave comparable results of permeability between to . The tortuosity of the CWFs was found from Hager's equation to range from to . In general, while the permeability of the CWFs decreased with increasing clay content, tortuosity increased with increasing clay content. The CWFs removed E. coli from aqueous suspension very efficiently with average log reduction values between 5.7-6.4. The implications and limitations of the results are discussed for the effective filtration of water in the developing world. (C) 2013 American Society of Civil Engineers. 

Filters; Flow rates; Permeability; Filtration; Porosity; Ceramic water filters; Porosimetry; Flow rate; Intrinsic permeability; Tortuosity; E; coli filtration