| By analysising the characteristics of7-ACA integrated wastewater, which contains high COD, high ammonia, and poor wastewater biodegradability,"Magnesium ammonium phosphate-UASB-Biomembrance A/O-BAC" processes were used to treat it. The main results were shown as following:Magnesium ammonium phosphate (MAP) precipitation was used for the pretreatment of7-ACA integrated wastewater to remove high strength ammonia nitrogen. MgCl2·6H2O and H3PO4, were chosen as the precipitants, the optimal operational conditions were determined as the initial pH value of9.0, the molar ratio of Mg2+, PO3-4and NH+4of1.0:1.1:1.0and reaction time of20min. The results indicated that the ammonia nitrogen removal efficiency was higher than85.0%when ammonia nitrogen concentration of the influent ranged from1020to1190mg/L. The ammonia nitrogen and residual phosphorus of the effluent were lower than150.0mg/L and40.0mg/L, respectively.A UASB was used to treat7-ACA integrated wastewater. After53days, the bioreactor was start-up successfully. The inhibit effect of7-ACA integrated wastewater on anaerobic digestion was severe. After261days of start-up, the removal rate of COD was higher than75.0%when the COD and ammonia concentration of the influent concentrations were6000mg/L and120mg/L, the volume loading reached6.0kgCOD/(m3·d) and the HRT was24h. The COD of the effluent was lower than1500mg/LBiomembrance A/O and BAC were used to treat7-ACA integrated wastewater. The removal rate of COD, ammonia nitrogen and TN were96%,90%and90%, when the reflux ratio R=3, the COD, ammonia and TN concentration of the influent were1500mg/L,120mg/L and400mg/L"Magnesium ammonium phosphate-UASB-Biomembrance A/O-BAC" processes were used to treat the7-ACA integrated wastewater. The COD, ammonia nitrogen and TN concentration of the effluent were90mg/L,15mg/L and38mg/L, meeting the level of Table2in the Discharge Standards of Water Pollutants for Pharmaceutical Industry Fermentation Products Category (GB21908-2008). |
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