COMPUTER SIMULATION OF A TWO-STAGE ANAEROBIC SEQUENCING BATCH REACTOR SYSTEM FOR ANIMALWASTEWATER TREATMENT

Abstract

The temperature-phased anaerobic digestion system is a newly developed biotechnology for organic wastewater treatment. A thermophilic-mesophilic two-stage anaerobic sequencing batch reactor (ASBR) system has been found to be a promising animal waste treatment system for energy recovery, odor control, and fecal bacteria destruction. A dual-substrate computer simulation model was developed in this study to predict the performance of a temperature-phased ASBR system for dairy wastewater treatment under different operating conditions. The model was calibrated and validated using the experimental data obtained from three laboratory-scale two-stage ASBR systems. It was predicted that with 1 :4 first- to second-stage volume ratio, the methane produced per unit reactor volume in the first-stage reactors of the temperature-phased ASBR systems is about twice as much as the methane produced in the second-stage reactors. This pointed out the potential for modifying the volume ratios between the two stages to optimize the system design. The two-stage ASBR model can be used for further evaluation of different multistage ASBR system systems to optimize the system performance and economics.