Fabrication of porous ceramic pot filters for adsorptive removal of pollutants in tannery wastewater

Abstract

The use of porous ceramic pot filters for wastewater treatment is considered a cost-effective technology however presence of appropriate pore size to trap pollutants and microorganisms from industrial wastewater remain a challenge. In this study, naturally available kaolin was first characterized and porous ceramic pot filters from different ratios of the kaolin to sawdust which served as combustible material and fired at 910 °C were produced. Ten different filters were fabricated with different mixing ratios of kaolin and sawdust. The clay materials were characterized for their chemical compositions, morphology and thermal stability using different analytical instruments. The performance of the regular and scrubbed ceramic water filters from the different proportions at different the flow rate, their porosities and removal efficiencies of some pollutants in tannery wastewater were evaluated The chemical compositions of the raw material (kaolin) contained oxides of silicon (51.03%) and aluminium (33.75%), respectively. Physicochemical and microbial analysis of the tannery wastewater were carried out using standard methods and the results of the analysis showed significant differences in the removal efficiencies of the pollutants by the various ceramic pot filters. The least porous filter pots coded (T8) containing 67% kaolin and 33% sawdust with flexural strength (55.53 MPa) was found most effective for the removal of COD (78.37%), BOD (91.66%), chloride (88.77%), nitrate (49.07%), sulphate (82.97%), TDS (86.84%), TSS (78.70%), TH (70.00 %) and TA (86.26%) compared to other fabricated pot filters (T1-T7, T9 and T10). All the ceramic filters exhibited excellent antimicrobial removal efficiency towards Fusarium chlamydosporium, Bacillus subtilis and Bacillus megaterium in tannery wastewater. From the results, it was concluded that regular ceramic pot filters performed better than the scrubbed filters due to the clogging effect of the former than the latter. Finally, the degree of porosity affects the performance and removal efficiency of the fabricated kaolin based filters.