Endocrine disrupter removal from wastewater using membrane bioreactor and nanofiltration technology

Endocrine disrupting compounds can affect hormone systems in organisms. However, conventional wastewater treatment plants are not able to remove these substances sufficiently before disposing effluent into the environment. Membrane technology, which is proving to be an effective barrier to these substances, is the subject of this research. The removal techniques under investigation are membrane bioreactors and nanofiltration. Initial results using wastewater from a dumpsite leachate plant indicate removal of more than 90% of nonylphenol (NP) and bisphenol (BPA). The mass balance indicates the membrane bioreactor is the most important process step in removal while the granulated activated carbon treatment, applied downstream, is a further polishing stage. Eleven different nanofiltration membranes were tested in the laboratory set-up. The observed retentions for NP and BPA ranged between 70% and 100%. The contact angle is an indicator for the hydrophobicity of a membrane, whose influence on the permeability and retention of NP was evident. Regarding the retention of BPA no dependency on the contact angle was observed.