Use of natural bio-sorbent in removing dye, heavy metal and antibiotic-resistant bacteria from industrial wastewater

In this study, we evaluated the ability of waste shell powder (WSP) and moringa seed powder (MSP) individually or in combination to eliminate dye, heavy metal and resistant bacteria from the industrial wastewater (IWW). The presence of dyes, heavy metals, approximately 7.0 log CFU/ml of aerobic bacteria and 3.0–4.0 log CFU/ml of other pathogens including Escherichia coli, Pseudomonas aeruginosa, Citrobacter freundii, Serratia liquefaciens and Bacillus cereus was evident in IWW of both tannery and textile industries. In addition, depending on the type of bacterial species each bacterium was resistant to as high as 50 ppm of multi-metal (Cr6+, Cd2+ and Pb2+ or its combination) and even multi-drug resistant (amoxicillin, ampicillin, cefixime, ceftazidime, and tazobactam). Combined use of MSP (0.8 gm/100 ml IWW) and WSP (0.2 gm/100 ml IWW) treatment was able to discolor the IWW within 4 h and took 24 h to eliminate heavy metals and pathogenic bacteria to non-detectable level from the IWW, simultaneously. On the other hand, individual use of MSP or WSP was not found effective enough to remove or eliminate dye, heavy metal and bacteria simultaneously from the IWW. Similar experimental results were observed in the challenge test with laboratory-prepared effluent water containing 35.0 ppm Remazol Brilliant Blue R dye and maximum 50 ppm Cr6+. Thus, the combination of these two bio-sorbents could be applicable in IWW treatment before being discharged into the environment.