Ceramic Water Filters: A Point-of-Use Water Treatment Technology to Remove Bacteria from Drinking Water in Longhai City, Fujian Province, China

Abstract

While provision of safe drinking water is considered a basic human right, there are major challenges in the developing world for its provision. The ability to deliver safe water using a cost-appropriate technology is a major aspect of the problem. One of the technologies that has the potential to contribute significantly is the ceramic water filter (CWF); however, as shown herein, there are significant differences between performance of CWFs in the laboratory and in field applications. The CWFs employed in this study (field and laboratory) have a pore fraction of 21.0 -22.4% and an average maximum pore diameter of 5.7 -15.2 μm. Field studies were completed in Longhai City, China, a rural community in southeastern China with red earth, high precipitation and intensive human/ domestic activities. During field trials, CWFs demonstrated an average removal efficiency of 94.7%, with values ranging from 75 -100%, whereas in laboratory studies, average removal efficiency was determined to be 99.5%, with values ranging from 97.7 -99.9%. Differences between the lab and field removal efficiencies are attributed to contamination of the filter element and receptacle by villagers during field utilization and cleaning. Effective technology transfer to the end-user is required to achieve the bacterial removal efficiency attainable by the technology itself.

Adopting a Preparatory Strategy to Respond to Water Security Issues Arising from Geo-Hazards

“…In field studies, as apparent from Figure 4, the E-coli removal efficiency associated with individual CWFs studied during field trials in Longhai, China. Farrow [27] reported field removal (i.e. by the villagers in Longhai), efficiencies of E.-coli ranging from 75-100% (as opposed to laboratory studies where removal efficiency was observed to range from 97.7-99.9%), with average E.-coli removal efficiencies in the field, and lab E-coli observed to be 94.7% and 99.5% respectively.…”

“…Training was identified as a factor contributing to the high usage of CWFs in both the Sri Lanka tsunami and Dominican Republic flooding interventions. Although the training was not extensive, and follow-up visits were not needed to ensure continued usage, some training at the outset on operation and maintenance of the CWFs was identified as "vital" [29,30,27]. It is necessary that all recipients be provided with all the materials necessary to use and maintain the CWFs including the filter element, plastic receptacle, brush for cleaning the element, etc.…”

“…These factors translate into the emergency context, and it is recommended that materials be developed specifically for the emergency context to assist organizations in conducting the training necessary to ensure project success [28]. Continued use of CWFs post-emergency as well as beyond, may occur (where villagers in Longhai specifically requested to be allowed to continue to use the CWFs [27].…”

Investigation of Maintenance Impacts on Flow Rates in Ceramic Disc Water Filters

“…Part of the reason for the widespread CWF adoption is that CWFs are low cost and are easily manufactured with minimal capital investment. The combination of these factors has enabled utilization of CWFs in many developing regions (van Halem et al, 2009;Murphy et al, 2010a, b;Ren and Smith et al, 2013;Mellor et al, 2014;Farrow et al, 2018).…”

“…Other persistent deficiencies of CWFs which must be considered as precautionary issues for CWF performance include relatively poor performance for removal of bacteria in the field (in contrast to laboratory studies) when there is contact by the CWF user with the exit side of a CWF (e.g., as with the clay pot) (Farrow et al, 2018). Further, the impact of silver impregnation on CWF bacterial removal efficacy is inconsistent (Fewtrell, 2014).…”