Field-scale assessment of soil, water, plant, and soil microbiome in and around Rania-Khan Chandpur Chromium contaminated site, India.

Rania-Khan Chandpur site, (Kanpur Dehat, Uttar Pradesh, India), one of the highly Chromium (Cr) contaminated sites in India due to Chromite Ore Processing Residue (COPR), has been investigated at the field-scale. We found that the area around the COPR dumps was hazardously contaminated with the Cr where its concentrations in the surface water and groundwater were > 40 mgL-1, its maximum contents in the COPRs and in the soils of the adjoining lands were 9.6 wt% and 3.83 wt%, respectively. By exploring the vegetation and microbial distribution across the site, we advocate the appropriateness of Cynodon dactylon, Chrysopogon zizanioides, Cyperus sp., and Typha angustifolia as the most suitable phytoremediation agent because their association with Cr remediating bacterial species (Pseudomonas sp., Clostridium sp. and Bacillus sp.) was strong. Using this remarkable information for the bioremediation projects, this site can be re-vegetated and bioaugmented to remediate Cr in soils, waterlogged ditches, surface water, and in groundwater systems.

Hybrid electrocoagulation and laccase mediated treatment for efficient decolorization of effluent generated from textile industries.

Enzymatic (laccase mediated) decolorization of dyes remains inefficient for recalcitrant dyes, which can be better handled by electrocoagulation (EC). However, EC is energy intensive and produce large amount of sludge. In light of the same, present study offers a promising solution for the treatment of textile effluent meeting surface discharge norms, using hybridization of enzymatic and electrocoagulation treatment. The findings revealed best color removal (90%) of undiluted (raw) textile effluent (4592 hazen) is achievable by employing EC using zinc-coated iron electrode at current density 25 mA cm-2 followed by partially purified laccase (LT) treatment, and activated carbon (AC) polishing at ambient conditions. Overall, the decolorization performance of Hybrid EC-LT integrated AC approach was 1.95 times better than only laccase treatment. Also, the sludge generation from Hybrid EC-LT integrated AC (0.7 g L-1) was 3.3 times lesser than EC alone (2.1 g L-1). Therefore, the present study recommends Hybrid EC-LT integrated AC could be potential approach to treat complex textile effluent sustainably with lower energy input and waste sludge generation.