Operation of fill-and-draw reactors fed with bisphenol A as sole carbon and energy source.

While there is ample evidence in the literature that many organic xenobiotics can be biodegraded as sole carbon and energy source by pure batch cultures of selected microorganisms, the same evidence is very limited for continuous or semi-continuous mixed-culture processes simulating biological wastewater treatment plants. This study investigates for the first time whether Bisphenol A (BPA) can be removed and used as sole carbon and energy source by mixed microbial cultures in a semi-continuous process. Four fill and draw bioreactors were inoculated with unacclimated soil and operated at various hydraulic retention times (HRT), in the range of 1.7-4.2 d, using a feed composed solely of BPA (115 mg/l), and mineral salts. At steady-state, the BPA removal in the four reactors varied in the range 7.5-19% and did not show a significant trend with the HRT. The maximum growth rate on BPA was measured in the range 0.29-1.54 d-1.