Study On Sludge Circulating Fluidized-pellet-bed Bioreactor For Wastewater Treatment

Fluidized-pellet-bed bioreactor is a sludge-granulation technique developed recently. This technique combin fluidized Pellet bed technique with granular sludge process perefctly. We change the supply method of oxygen and introduce sludge recycling into fluidized-pellet-bed bioreactor (FPB), and carry out a pilot test on municipal water treatment. This experiment studies effectiveness of Sludge Circulating fluidized-pellet-bed bioreactor for removing pollutants. The results show that:(1) Fluidized-pellet-bed bioreactor can create great granular sludge with high concentration, which is good for high-rate of solid/liquid separation.(2) The diameter of granular sludge is about 1-5mm, which have yellow exterior and black interior. As the height of FPB, the size of granular sludge become more and more smaller(3) Fluidized-pellet-bed bioreactor create ideal circumstance for microorganism, and the biomass of granular sludge can measure up 108/g; The biological phase of FPB is abundant.(4) The total HRT is lower than that of conventional activated sludge process, just 1.2h. And the removal rate of pollutants(COD,NH3-N,TP) is 79%,64%,59%.(5) The result of FISH show that:there are a lot of nitrifying bacteria and denitrifying bacteria in the Fluidized-pellet-bed bioreactor; the granular sludge can make simultaneous nitrification and denitrification.(6) Physicochemical processes also play a role in wastewater treatment as biological one; the concentrations of the DO,COD,NH3-N,TP are gradually reduced along the height of fluidized-pellet-bed bioreactor; The separation of TP is mainly a chemical process.(7) The result of pilot test on municipal water treatment is good, the removal rate of pollutants(COD,NH3-N,TP) is 77%,36%,62%. The fluidized-pellet-bed bioreactor can not only separate solid-liquid efficiently, but be able to remove nitrogen and phosphor from water as well...