Kinetic study of the effect of bisphenol A on the rates of organic matter removal, decay and biomass generation in a membrane bioreactor

Abstract

This study analyzed the effect of bisphenol A (BPA) on the kinetic behavior of the heterotrophic biomass of a membrane bioreactor (MBR) treating municipal wastewater in order to determine possible variations in the rates of organic matter removal, decay and biomass generation. Four operation phases were analyzed in the steady state at different values of hydraulic retention time (6–10h), mixed liquor suspended solids (4000–7000mgL−1), temperature (12.1–31.1°C), and sludge retention time (9.81–21.67day). A respirometric procedure was used to model the kinetic behavior of heterotrophic biomass contained in the MBR in absence and presence of BPA, and a multivariable statistical analysis was applied to determine the effect of the variables on the substrate degradation rate for organic matter removal (rsu,H), decay coefficient for heterotrophic biomass (bH), and net heterotrophic biomass growth rate (ŕx,H). The results showed that there was no inhibitory effect of BPA on heterotrophic biomass, with higher values of rsu,H and ŕx,H, and lower values of bH in presence of BPA. Heterotrophic biomass from phase 2 showed the highest values of rsu,H (190.22mgO2L−1h−1), bH (0.1304day−1) and ŕx,H (170.68mgVSSL−1h−1) in presence of BPA due to its higher temperature (31.1°C).