Application of a Dye-Decolorizing Pseudomonas aeruginosa Strain ZM130 for Remediation of Textile Wastewaters in Aerobic/Anaerobic Sequential Batch Bioreactor and Soil Columns

Abstract

In this study, a pre-isolated dye-decolorizing bacterium, Pseudomonas aeruginosa ZM130, was tested to explore its potential for the treatment of synthetic and real textile wastewaters in aerobic and anaerobic bench-scale sequencing batch bioreactors (SBRs) as well as in constructed soil columns. The decolorizing ability of strain ZM130 against reactive black-5 (RB5) was optimized following a response surface methodology (RSM)-based approach, and this strain was observed to effectively decolorize RB5 even in presence of a substantial quantity of NaCl salt along multi-metal mixture including Cr6+, Pb2+, Cd2+, and Zn2+. In the SBR containing the immobilized cells of the strain ZM130, more than 80% of the RB5, hexavalent chromium [Cr(VI)], and chemical oxygen demand (COD) were removed from the textile wastewater under partially anaerobic condition using yeast extract as an additional carbon co-substrate. Furthermore, while studying the bioremediating ability of strain ZM130 in constructed soil columns, the maximum color removal (> 90%), Cr(VI) removal (> 95%), and COD removal (> 90%) were achieved in the soil columns bioaugmented with ZM130 together with either sludge or yeast extract. Interestingly, it was further noticed that soil columns augmented with P. aeruginosa ZM130 also showed maximum color removal from real textile wastewater in vertical columns filled with sterilized (> 87%) and non-sterilized soil (> 91%). Based on the results of the present research work, it can be concluded that P. aeruginosa ZM130 can serve as an excellent potential candidate for treatment of textile wastewaters in bioreactors as well as in soils.