Diclofenac removal from the wastewater using activated sludge and analysis of multidrug resistant bacteria from the sludge

Diclofenac is an anti-inflammatory drug and has been frequently detected from the wastewater. In the present study, factors affecting diclofenac adsorption on sewage sludge was evaluated. At 1 mg/L initial diclofenac concentration, more than 80% diclofenac removal was achieved. Adsorption increased at higher concentration (100 mg/L concentration) and more than 99% diclofenac was adsorbed from the wastewater. Significant removal of diclofenac was observed after 5 min contact time. The adsorption efficacy was more than 98% after 50 and 60 min. Pseudo-first and second order kinetics revealed reasonable regression value (0.9) indicated that the model is best fitted. Diclofenac adsorption was extremely high at acidic pHs than alkaline range. The sludge samples showed the presence of multi drug resistant bacteria. Vancomycin-resistant entemcoccus stains were 27%, Methicillin-resistant Staphylococcus aureus positive strains were 16.5% and Extended-spectrum betal-lactamaseharbouring Entembacteriacea were 65.4% in the sludge. The drug resistance Entembacteriaceae revealed 14 Klebsiella pneumonia strains, 11 strains from E. coli and two from the genus Enterobacter. To conclude, the activated sludge could be effectively utilized for the removal of diclofenac from wastewater.

Automated summary

Factors affecting the adsorption of diclofenac on sewage sludge were evaluated in this study. Over 80% diclofenac was removed at an initial concentration of 1 mg/L. Adsorption increased at higher concentrations, and more than 99% of diclofenac was adsorbed at a concentration of 100 mg/L. Significant removal of diclofenac was observed after 5 minutes of contact time, and the adsorption efficacy was over 98% after 50 and 60 minutes. The results of pseudo-first and second order kinetics showed a reasonable regression value, indicating a good fit for the model. Diclofenac adsorption was more effective at acidic pH levels than alkaline levels. The sludge samples contained multi-drug resistant bacteria, including vancomycin-resistant entemcoccus stains, methicillin-resistant Staphylococcus aureus positive strains, and extended-spectrum betal-lactamaseharbouring Entembacteriacea. Klebsiella pneumoniae, E. coli, and Enterobacter were among the drug-resistant Entembacteriaceae strains found. In conclusion, activated sludge can effectively be used for the removal of diclofenac from wastewater.