Ceramic 'Pot' Water Filters: Investigations into Manufacturing and Performance
'pot' water filters (CWF) are widely used to improve the microbiological quality of
drinking water at the point of use. CWFs are manufactured at >50 filter factories
worldwide by pressing a mixture of clay and a burn-out material into the filter shape,
which is then fired to a ceramic state. Silver is added during this process as a
bactericide. In 2011, the Ceramics Manufact... read moreuring Working Group (CMWG) developed
recommendations to, "provide guidance to assist filter factories in producing the
lowest-cost, most-effective ceramic filters possible". The focus of this dissertation
was to further this aim. Specifically, to: 1) investigate the effects of silver type,
silver concentration, and input materials on CWF performance; 2) evaluate filter
distribution programs; 3) develop a framework for evaluating manufacturing quality
control protocols; and 4) synthesize research findings through a systematic literature
review. Overall, results suggest that in households filtered water quality meets the
low-risk guideline and filter use has been associated with a reduction in diarrheal
disease. However, local context, including source water quality, time in use and supply
chain access, likely influence long-term filter use and can affect in situ technology
performance evaluation. Results from laboratory investigations and the systematic review
demonstrate filters can achieve ≥2 log reduction in bacteria; however, silver
should not be relied on as a principal treatment mechanism for long-term filter
performance. Thus, it is recommended that filters be tested for bacteria removal prior
to silver application. Burn-out material particle size and clay content (<2µm)
are associated with bacteria removal by the porous matrix. Lastly, with participation
from factories, a framework for evaluating quality control protocols was developed. CWFs
are widely manufactured, promoted and used; thus, there is a need to continue supporting
factories in manufacturing high-quality filters and to broadly disseminate research
Thesis (Ph.D.)--Tufts University, 2018.
Submitted to the Dept. of Civil Engineering.
Advisor: Daniele Lantagne.
Committee: David Gute, Derek Chitwood, and Kishore Pochampally.
Keyword: Environmental engineering.read less