Papers by Author: Hui Jia

Abstract: The characteristics of removing COD and nitrogen simultaneously in membrane aerated biofilm reactor (MABR) was investigated in different packing densities and circulation flow rates. The results show that better removal rates of COD and ammonia nitrogen are found under the packing density of 30%, which removal rates are 76% and 65% respectively. Observations through the electron microscopic and CCD camera reveal that the biofilm have a layered structure and the stable biofilm thickness is 1.652 mm. When the circulation flow rate is 7.62 L·min^-1, the highest removal rate of total nitrogen is 70%, meanwhile, the efficient mass transfer of the biofilm is ensured.

Abstract: Based on the characteristics of non-uniform distribution in the fouling of hollow-fiber membrane, the non-uniform distribution of local flux and redistribution with different fiber length (0.6 m、1.2 m、1.6 m) was investigated experimentally. Experiment was conducted under the condition of operating flux 20 L/m²h (20 LMH). The results indicated that the longer fiber length was, the greater difference in local pressure and the more non-uniform the local flux distributed. Under operating mode of critical flux, the flux distribution in the length of 1.6 m membrane fiber is the most non-uniform with the fastest fouling rate. In addition, the distribution of local flux is more uniform for 0.6 m fiber under the operating flux of 16 LMH, which also slow down membrane fouling significantly. Shorter membrane fiber generally exhibited higher uniformity in the local flux distribution and slower development rate of membrane fouling.

Abstract: Adopting standard k-ε turbulent model and mixture flow model, settling process and decant process was simulated using 3-d numerical simulation in M-ICAR(Mixture-Intermittently Cycle Aeration Reactor) process to analyze the changes of sludge phase volume fraction. The simulation results showed that the changes of feeding wastewater had great influence on sludge settle ability in decant process, and the position of decanter needed optimized; it had no influence on sludge settle ability in settling process. For considering the lowest hydraulic retention time, the research controlled maximum feeding wastewater for 1610m3/h. Internal recycle had no influence on sludge settle ability. Two methods were proposed: the first one, the water level of decanter was set 3.9m (sludge volume fraction of this suspended area was less than 0.05), feeding velocity was 0.07 m/s; the second, keep the water level of decanter 3.75 m, reduce feeding velocity (preliminary setting feeding velocity 0.06 m/s). The two methods had no influence on sludge settle ability.