Study On The Removal Of Bisphenol A In Synthetic Wastewater By A Sequencing Batch Reactor

This thesis emphasized on the operational parameters and the primary mechanism for the removal of bisphenol A (BPA) in synthetic wastewater in a sequencing batch reactor (SBR) with anaerobic - aerobic - anoxic running mode.The concentration of bisphenol A was measured by HPLC. Several operational parameters of SBR such as hydraulic retention time (HRT) , sludge retention time (SRT) and the ratio of aerobic to anoxic time were changed to investigate their effects on BPA removal efficiency. The results indicated that BPA can be effectively removed in SBR. Furthermore, it was observed that hydraulic retention time (HRT), the ratio of aerobic to anoxic time and sludge retention time (SRT) matter a lot on the degradation of BPA, and comparatively, long HRT, SRT and more ratio of anerobic time were beneficial to the removal of BPA. The optimum operation parameters for both nutrient and BPA removal are: HRT=480min, SRT=25d and the anaerobic, aerobic and anoxic times are 90min, 150min and 180min, respectively.Under the above optimum conditions, the BPA removal efficiency attained the level of 99%, of which anaerobic, aerobic and anoxic phases accounted for the BPA removal percentages of 66%, 32% and 1%, respectively; the removal efficiency of COD attained the level of 89%, of which anaerobic, aerobic and anoxic phases accounted for the COD removal percentages of 82%, 4% and 3%, respectively; the removal efficiency of TN attained the level of 69%, of which anaerobic, aerobic and anoxic phases accounted for the TN removal percentages of 50%, 9% and 10%, respectively; the removal efficiency of PO₄^3--P attained the level of 95%, of which anaerobic, aerobic and anoxic phases accounted for the PO₄^3--P removal percentages of 0%, 93% and 2%, respectively.It was found that BPA was removed because of adsorption, barely because of degradation in the anaerobic phase, and the removal efficiency by adsorption in the anaerobic phase attained the level of 60%; then in the aerobic phase, BPA was further removed by biological degradation, the extent of degradation in the aerobic phase was the most fundamental factor for the removal of BPA, which was closely related with the extent of cumulation of BPA in the residul activated sludge; the anoxic phasebarely influenced the removal of BPA.