Treatment of refractory organics in secondary biological treated post tanning wastewater using bacterial cell immobilized fluidized reactor

Abstract

The major problems encountered in conventional biological treatment are the microbial cultures were insensitive to degrade the refractory organics in wastewater. The biological treatment system must contain robust microbial consortia to adapt the environment and to treat the refractory organics in wastewater. In the present investigation, the efficient microbial consortium was isolated and immobilized onto carbon-silica matrix (CSM) at the density of 3.31 ± 0.2 × 107 cells gm−1 of CSM and the same was used in the fluidized reactor to remove the refractory organics in wastewater. The bacterial cell immobilized fluidized reactor (CIFR) exhibited the performance that CODtot and CODdis were removed by 43 ± 2.8% and 42 ± 3.3% respectively in 24 h under batch mode of operation. The mineralization of refractory organics from wastewater under batch study was confirmed using UV–Visible and FT-IR spectroscopic studies. The CODtot and CODdis were removed by 43 ± 8.4% and 50 ± 8.4% respectively with remaining of CODtot, 625 ± 86 mg/L and CODdis, 502 ± 91 mg/L in the treated post tanning wastewater under continuous mode of operation using CIFR with the organic loading rate of 1.0 ± 0.1 kg COD/m3/d. The phylum Proteobacteria showed the relative abundance by 53.53% in the total bacterial community and played the major role in the degradation of refractory organics in wastewater.