Start-Ups Of UASB Reactors And Characters Of Anaerobic Granular Sludge

The start-up process and dynamics of Up-flow Anaerobic Sludge Bed (UASB) Reactors were discussed in this thesis. The effects of various factors on the product gas activity and the oxygen tolerance of anaerobic granular sludge (AGS) were also discussed.When the HRT rate change from 60 h to 20h, the gas production of UASB reactor would obviously increase (the rate is 100%). It took less time to start-up a UASB reactor by only using the remainder sludge of anaerobic digestion and activated sludge as seed than by using flocculent sludge of UASB reactor. Inert materials, such as activated carbon and sand crystal, could start the formation of anaerobic granular sludge when they are adding in UASB reactors during the start-up. It took 40d to start-up a 13L UASB reactor with 500g remainder sludge of anaerobic digestion and 7.5L activated sludge as seed, 10h~20h HRT and sand crystal as inert carrier. The time was 15d shorter than a similar technology, which treat the same synthetic wastewater. As far as a stably running reactor is concerned, there is a certain relative among the influent volume and the concentration of influent and effluent and the gas production. The relative is affected by the condition of performance and environment.To the product gas activity (PGA) of the AGS used in the experiment, 34. 5 was the optimal treatment temperature. Storage under 4 and dewatering rate of 29.5% was favorable to remaining of the PGA. The PGA of sludge could be enhanced by the following conditions: 1.86mM (SO42-) and 5.49mM K\ 4.50mMMg2+, 2.50mM Ca2+, 2.14mM Fe2+, 2.15mM Zn2+. In addition , these values were the optimums. However, Cu2+ would hold up the sludge to product gas.The special composition and structure of the AGS cause the sludge has some oxygen tolerance, which is affected by various factors. The AGS would tolerance 0.5h aerates without obvious activity loses. When environment pH was neutral, the oxygen tolerance was the highest. 0.0067g/mL Sodium glutamate and 0.0033g/mL KIwould improve the oxygen tolerance of the AGS, while 0.0033g/mL Na2S and 0.0067g/mL vitamin C and 0.0033g/mL NaHSO3 would restrain the oxygen tolerance of the AGS. Storage under 4 and dewatering rate of 37.6% would lower the lose of the oxygen tolerance. The oxygen tolerance of sludge could be improved by metabolism of some microorganisms. Furthermore, some metabolites of those microorganisms also have the ability to enhance the oxygen tolerance.