Influence of bisphenol A concentration on organic matter removal and nitrification in biological wastewater treatment

Microplastics and plastic additives have become ubiquitous in our environment, posing a major challenge to wastewater treatment processes. This study investigated the impact of Bisphenol A (BPA), a common plastic additive, on the efficiency of organic matter removal and nitrification in biological wastewater treatment. The obtained results indicated that a BPA concentration of 10 mg & sdot;L- 1 in the influent affected the Chemical Oxygen Demand (COD) in the effluent. In comparison, concentrations of 1 or 5 mg & sdot;L- 1 did not show such noticeable differences. Additionally, an increase in BPA load inhibited the nitrification process, resulting in a high concentration of nitrogen in its ammoniacal form in the effluent when the BPA concentration was increased to 10 mg & sdot;L- 1. In fact, the microbial community analysis revealed a considerable reduction of Nitrosomonas in the reactor fed with wastewater containing 10 mg & sdot;L- 1 of BPA. Despite compromising the nitrification process, this situation did not deprive the biomass of its ability to remove BPA from the system, as this component was not detected in the effluent once the microorganisms completed their adaptation process. 16 S rRNA gene sequencing showed that the predominant phyla across all samples were associated with Proteobacteria, Bacteroidota, Patescibacteria and Actinobacteriota, similar to previous studies.