Prevalence of antibiotic resistant genes in selected activated sludge processes in Isfahan Province, Iran

In this study, degradation of p-chlorophenol (p-CP) was evaluated using persulfate (PS) activated zerovalent iron (ZVI) based ultraviolet (UV) in a bench scale photoreactor. The effect of operational parameters such as solution pH (3, 7, and 11), reaction time (0-60 minutes), ZVI dosage (0.15, 1.25, 0.5, 1, and 1.5 mM), PS concentration (0.5, 1.5, 2, 2.5, 3, and 4 mM), and initial p-CP concentration (0.22, 0.44, 0.88, 1.32, and 1.76 mM) were examined on the degradation of p-CP in batch experiments. The experimental results indicated that the p-CP removal rate significantly depends on operational parameters. The highest p-CP removal rate was achieved after 45 minutes (> 0.99%) in pH = 3, ZVI = 1 mM, and PS = 3 mM, and with initial p-CP concentration = 0.44 mM. The results revealed that excess amount of PS and ZVI could reversely affect p-CP removal efficiency. In addition, an increase in p-CP initial concentration from 0.22 to 1.76 mM significantly decreased its removal rate. This study indicated that PS activated ZVI based UV process is practically feasible for the effective degradation of p-CP in aqueous solution.

Keywords:

Activated sludge , Antibiotic resistance genes (ARGs) , wastewater , A-B process , Extended aeration