Effects Of Organic Loading Rate On The Substrate Degradation Along The Compartments And Energy Recovery Efficiency In An ABR

Anaerobic biological treatment technology is widely applied and studied due to its advantage of treating high loading wasterwater as well as recovering biogas. Howerver, several shortage was found such as long starting time and lack of stability. Based on the theory of bio phase-separation, anaerobic baffled reactor(ABR) was developed to provide appropriate circumstance for anaerobic microbial population, which promoted the degradation and transformation of organic compounds by a form of food-chain system improving the efficiency and stability substantially. But the understanding of inner connection about substrate degradation along the compartments on ABR and bio phase-separation characteristics is still not deep enough.The optimization of process control conditions, based on energy recovery, are also rarely studied. For regulate and control operation of ABR, in this paper the effects of organic loading rate(O LR) on the treatment efficiency and energy recovery were studied. And COD degradation kinetics was analyzed along ABR by Andrews dynamics model, which was further applied to reveal the correlation of treatment efficiency and energy recovery rate. These results can provide a basis and guidance for the optimal control of ABR and comprehensive efficiency improvement.During the operation period, the influent CO D concentration was maintained at 4000 mg·L-1. When HRT shortened from 48 h to 16 h, the average CO D removal efficiency of the system was maintain about 90%. When HRT was 48 h, the influent COD was mostly removed in the first chamber, while HRT shorting to 16 h the COD removal was in the four chambers. Through the analysis of methane content of biogas and CO D removal effic iency, the increase of O LR by the HRT shorten enhanced the bio-phase separation and stability of ABR. During HRT 40 h, energy recovery efficiency of the system was reached a maximum of 60.5%.The effct of O LR on the bio-phase separation and treatment efficiency of ABR was studied with increased CO D in stages and constant HRT 40 h. When the influent COD increased from 2000 mg·L-1 to 8000mg·L-1, the CO D removal rate increased to 87.7% from 96.4%. The fermentation intermediate VFA was mainly generated in the first chamber and subsequent stepwise transformed and consumed along the ABR. The degradation of butyric acid and propionic acid degradation occurred mainly in the second and third grid chamber, respective ly. And biogas production significantly increased from 13.1 L·d-1to 63.8 L·d-1. The biogas yield in the first two chambers occupied 80% of the total gas yield, while the methane content decreased gradually with the increase in load. The energy recovery efficiency decreased, when the influent COD increased.Andrews degradation kinetics model can be applied to simulate the substrate degradation process along the compartments. The obtained kinetics parameters k, Ks and K i was used to analyze the comprehensive characterization of bio-phase separation in ABR. The simulation results suggested that acidogens was dominate in the first chamber, while acetogens and methanogens was dominate in the second and third chamber. The fourth chamber was a redundant systems, which allows the system to run at a higher organic load and help protect the water quality in the effluent.