Study On Granulation In The Anaerobic Baffled Reactor With Inert Carrier Under Room Temperature

Two lab-scale Anaerobic Baffled Reactors are used in this study to culture granular sludge under room temperature(21℃～25℃). One of the two reactors (called reactor B) is put in inert carriers at the same time with anaerobic sludge, as the other one (called reactor A )is put in anaerobic sludge only acting as a control reactor. This study assesses the influence of the Polyacrylamide and Bentonite addition on granule formation and disposing effect of ABR reactor. The result indicates that:(1) Polyacrylamide and Bentonite addition accelerates the formation of granule of the ABR reactor.After 162 days, abundant granular sludge are obtained in each compartment of reactor B, but only in the initial compartment of reactor A. Granules bigger than 0.5 millimeter reach 57.6% to 72.7% in the four compartments of reactor B and only reach 67.3% in the first compartment of reactor A, this value is slightly lower than the first compartment of reactor B at the same period. Granules bigger than 0.5 millimeter reach 31.3% to 34.7% in the other three compartments of reactor A, which is almost half value to the corresponding compartments of reactor B.(2) Polyacrylamide and Bentonite addition improves the disposing efficiency of ABR reactor.①Reactor A and reactor B start-up at the same time with same volume load. According to the different increasing extent of volume load, the entire process of the two reactors is divide into different stages. Reactor B functions better than reactor A and the volume load increases faster. After 162 days, reactor B operates 7 stages, the final volume load (OLR) reach 4.15 kgCOD/m~3·d and the shortest hydraulic retention time (HRT) reach 12 hours. For reactor A, it just operates 5 stages after runing 162 days, the maximum load capacity is only 2.23 kgCOD/m~3·d and the shortest HRT is 24 hours. ②The required runing time to increace the volume load from the initial 0.5 kgCOD/m3·d to 2.23 kgCOD/m~3·d is 162 days for reactor A, but only 130 days for reactor B. After the reactor B operates 50 days, the COD removal efficiency can be maintained at more than 85%. The reactor A has to run 110 days to reach this level.③The VSS/SS value of the two reactors increase with the operate time, and the increase of organic contents are most significant in the first compartment of the two reactors. When the reactor B operates to 128 days, the VSS/SS value in every compartment is bigger than the corresponding compartments of reactor A. At the end of the experiment, the average value of VSS/SS is 0.787 and 0.862 respectively.