Advanced oxidative degradation of bisphenol A and bisphenol S

Abstract

In this study, the degradation of two emerging contaminants, bisphenol A (BPA) and bisphenol S (BPS), in spiked water and secondary treated waste water samples were investigated using four different oxidation methods: ultraviolet C (UVC) (254 nm), UVC/hydrogen peroxide (H2O2), ozone (O3) and ultraviolet A (UVA)/ozone (365 nm). Investigation of the effect of light intensity on the rate constants of UVC and UVC/hydrogen peroxide processes and identification of intermediates in the degradation process were conducted. The highest degradation rates were achieved for the UVA/ozone process with k values of 2·2 or 1·9 min−1 in secondary treated waste water (absorbance at 254 nm = 0·164 AU). Based on the results, the fate of BPA and BPS in municipal waste water as they move through the UV (254 nm) disinfection unit of a local waste water treatment plant in Calgary, Canada, was evaluated. It was concluded that in the UV disinfection unit, only 1% and 6% of BPA and BPS were degraded respectively. However, should 0·042 M hydrogen peroxide be added to the waste water stream entering the disinfection unit, 56% of BPA and 47% of BPS can be degraded. By implementation of ozone and UVA/ozone processes, degradation levels could exceed >95%.