Production of Ammonia in a Packed-Bed, Anaerobic Upflow (ANFLOW) Bioreactor

摘要

The objective of this study was to monitor effluent ammonia concentrations and ammonia production rates within the ANFLOW bioreactor as influent soluble chemical oxygen demand (SCOD) concentrations and flow rates were varied. Correlations between influent organic loadings and effluent ammonia concentrations and ammonia formation were sought. Subsequent ammonia removal methods were proposed. A packed-bed, aerobic upflow bioreactor was tested for nitrification of effluent ammonia for the ANFLOW bioreactor. Removal rates of SCOD ranged from 87 to 95% within the ANFLOW bioreactor. The most efficient SCOD removal occurred at the highest organic loading rate (OLR). Profiles of SCOD and volatile acids concentrations showed distinct regions of complex organics breakdown and wastes stabilization. Hydraulic flow within the ANFLOW bioreactor behaved approximately as in a plug-flow reactor. The effluent ammonia concentration appeared to be a function of hydraulic loading rate (HLR). For a given OLR or influent SCOD, effluent ammonia concentrations were less at the higher flow rate. These results suggest that, at the shorter hydraulic residence time (HRT), there was less time for ammonia accumulation and that conversion of organic-nitrogen to ammonia-nitrogen could not be fully completed. However, overall ammonia-nitrogen formulation (in terms of grams produced per day) was found to be a linear function of OLR. The figures presented could be used for predicting ammonia formation for a given OLR or effluent ammonia concentration for a given OLR, HLR, or SCOD. It was demonstrated that the ammonia can be nitrified using a packed-bed aerobic upflow bioreactor with only 5% of the volume of the ANFLOW bioreactor and an HRT of only a few hours. A series of packed-bed bioreactors was recommended for carbon removal-waste stabilization, ammonia removal, and denitrification. (ERA citation 06:034428)