Studies On High Efficient Separation Biological Fluidized Reactor

High efficient separation biological fluidized reactor (HSBFR) is a kind of new biological reactor that is improved on inner circulation three phase biological fluidized bed. As there are some shortcomings in conventional double cylinders inner circulation three phase biological fluidized bed, honeycomb type cross section is adopted in HSBFR. There are aerobic zone and anoxic zone in one reactor, and biological fluidized bed is combined with dissolved air floatation. Total height and diameter ratio of HSBFR is reduced, volume of single reactor is increased, and removal effect of suspended solid is improved. In order to separate biological carrier particles from the effluent of reactor, maze typed carrier separator is designed. In order to reduce water and air ratio and energy consumption in HSBFR, light-weight and economical rubber carrier is adopted. By experiment study, relationship of gas holdup, liquid circulation velocity and oxygen transfer coefficient along with reactor structure and operation parameters are gained. By theory analysis, relationship of riser gas holdup and downcomer gas holdup in HSBFR reactor is deduced; superficial gas velocity, resistance parameters, downcomer and riser area ratio et al. main parameters that influence liquid circulation velocity are optimized. Conclusion that liquid circulation velocity is proportional to 0.5 mathematical power of reactor height is obtained. By measuring the distribution curve of retention time, using non-equal volume CSTR (continuous stirred tank reactor) series model, the results that HSBFR is equivalent with 1.6 CSTR series in experiment range show. According to the continuity equation, the momentum equation, and the energy equation for mixture, software Fluent is used to simulate flow regime in HSBFR reactor. Static pressure distribution and relationship of gas holdup and liquid circulation velocity in reactor riser, downcomer and local zones are obtained by simulation. Influence of height and diameter ratio, downcomer and riser area ratio, and reactor bottom gap height to reactor performance is analyzed, in addition, span of reactor bottom gap height is optimized. Competitive relationship of suspended microbe and attached microbe in HSBFR reactor is investigated, and conclusion is improving organic loading, reducing suspended microbe, reducing liquid circulation velocity and gas holdup can increase the amount of attached microbe. Removal volume loading of HSBFR can reach to the average value of 8.53 kgCOD/m3.d during the treatment of domestic wastewater, and nitrifying effect is improved when HRT is increased. Nitrifying effect is restricted factor for total nitrogen removal in aerobic-anoxic HSBFR reactor, and the SS concentration of effluent is lower than 20 mg/L. If chemical method for phosphorous removal is adopted in HSBFR, the total phosphorous concentration of effluent is lower than 1.0mg/L, and the cost for chemical phosphorous removal is 0.10-0.15 yuan/m3 wastewater.