Removal of twelve endocrine disrupting compounds from wastewater using two laboratory-scale batch-type bioreactors

Abstract

This study employed two batch-type bioreactors for the treatment of twelve environmental contaminants with the potential to disrupt the normal function of the endocrine system. The contaminants included bisphenol A, two alkylphenols, two hormones, six organochlorine pesticides and one organophosphate pesticide. Synthetic domestic wastewater was prepared daily in the laboratory and fed to the bioreactors. The bioreactors were operated at two different sludge retention times and the parameters used to evaluate their performance were chemical oxygen demand, ammonium, orthophosphate, pH, temperature, dissolved oxygen and mixed liquor suspended solids. Upon reaching optimum operational conditions, the analytes were spiked into the bioreactors and the removal efficiencies were calculated with respect to the influent concentration. Satisfactory removal efficiencies (> 88%) were recorded for all twelve analytes as validated by the decline in ammonium, chemical oxygen demand and orthophosphate amounts. Sludge samples from the two bioreactors were analyzed at the end of the study, but none of the analytes was detected according to the detection limit of the method. The simple and efficient bioreactor system reported in this study was successfully used to remove twelve different endocrine disrupting compounds from wastewater, and this can be easily replicated with low financial cost.