Development of Ceramic Water Filter Clays Selection Criteria
By using well-established geosciences, environmental and geotechnical engineering methodologies, our study is the first to assess systematically how mineral compositions impact the microbiological removal on clayey materials and CWFs mineral composition have an impact on the performance and life span of CWFs. Compared to previous studies, our study showed similar trends when P. fluorescens were used on diverse materials; biofilm formation on Canadian clayey material containing kaolinite was higher than on Guinea-Bissau clayey material, which contained montmorillonite. Moreover, in Guatemalan clayey material, albite contained Na+, which can be exchanged with H+ in the culture medium to increase bacterial attachment on the positively charged mineral surface. Muscovite has a high bacterial adhesion, which promotes biofilm formation in Guatemalan and Canadian clayey materials. Montmorillonite decreases biofilm formation in Guinea-Bissau clayey material, but does not play a decisive role in Guatemalan clayey material. Heavy metals in sawdust ashes have the potential to lower biofilm formation on CWFs in general, when compared to initial materials—this is supported at least for Guatemalan and Canadian samples. Our data suggest that the presence of muscovite in the CWF material causes significant differences in biofilm coverage, as shown by pairwise analysis of (1) Guatemalan (+muscovite) and Guinea-Bissau (–muscovite) CWFs and (2) Canadian (+muscovite, +hematite) and Guinea-Bissau (–muscovite, +hematite) CWFs. However, the small observed differences of biofilm formation between clayey material and CWF of Guinea-Bissau cannot be fully explained by heavy metal loading through firing with ash incorporation or montmorillonite loss coupled to hematite ingrowth, due to initially lower biofilm coverage on related clayey material. In summary, our study has laid groundwork for a standardization process for clayey material selection criteria for ceramic filter factories around the world.
"Development of Ceramic Water Filter Clays Selection Criteria"
Dissertations and Master's Theses (Campus Access).