Determining the optimum Fe-o ratio for sustainable granular Fe-o/sand water filters

作者：Bratkeu K B D; Olvera Vargas H; Tchatchueng J B; Noubactep C^*; Care S

来源：Chemical Engineering Journal, 2014, 247: 265-274.

DOI：10.1016/j.cej.2014.03.008

• Fe-o/sand filters
• Particle cementation
• Permeability loss
• Water treatment
• Zerovalent iron

Packed beds of metallic iron (Fe-o) and sand are tested for their efficiency at discoloring an aqueous methylene blue (MB) solution (2.0 mg L-1) in gravity driven systems for up to 95 days. The aim was to determine the optimal Fe-o/sand ratio for sustainable filters. Six different Fe-o/sand volumetric ratios were explored: 0/100, 20/80, 30/70, 40/60, 60/40 and 100/0. The columns were characterized by (i) the time-dependant extent of MB discoloration and (ii) the evolution of the hydraulic conductivity (permeability). Results clearly showed increased permeability loss with increasing Fe-o ratio. The Fe-o/sand ratio dependent extent of MB discoloration was not monotone. These observations corroborated the working hypothesis that properly designing a Fe-o/sand filter is finding a compromise between: (i) increased sustainability by lowering Fe-o ratios and (ii) decreased efficiency by lowering Fe-o ratios. This work provided the first experimental evidence for an optimal Fe-o/sand volumetric ratio of 25/75. This result will accelerate efforts for nonsite-specific system design.

• 出版日期2014-7-1