| In order to solve the problems encountered in the treatment of in municipal wastewater in south China, this study developed a novel continuous-flow integrated biological reactor (CIBR). To simplify the wastewater treatment process, CITR utilized the spatiotemporal sequencing relation of A2/O and conventional SBR and firstly used three-phase separator to achieve the simultaneous removal of nitrogen and phosphate in a single tank. Since the reaction zone and settling zone were integrated in CITR, the continuous water flow can be maintained at constant level, the energy consumption for sludge return was reduced, the problem of incomplete separation of solid and liquid was solved and the discharged water quality was improved. The main conclusions are drawn as follows.(1) The removal efficiency by facultative treatment in CIBR was greatly influenced by water temperature. When water temperature was below 12 oC, the removal efficiency declined sharply and the flowing out of sludge was great. When CITB was run in chemical assistant facultative mode at low temperature, the sludge settling can be improved to some extent, but the nitrification and denitrification efficiency can not be increased. When the water temperature was low or the NH3-N concentration was high, it was difficult to run CIBR in facultative mode or in chemical assistant facultative mode to attain the requirement. So, it was necessary to change the running mode to improve treatment efficiency.(2) Optimal conditions in CIBR were obtained as HRT of 12 h, MLSS of 3000 mg/L and SRT of 15 d. The treatment efficiency was influenced by the ratio of aeration, agitation, and settling time, the aeration ratio, the aerating power, the carbon source, the sludge load (Ns) and the average energy consumption. Though the influent COD concentration was low, a good simultaneous removal of nitrogen and phosphate could be achieved by the continuous influent and sufficient nitrification and denitrification. Somewhat synergistic effect on the removal of nitrogen and phosphate was obtained when CIBR was assisted by chemical intermittent aeration. The addition of coagulant attributed to nitrification and NH3-N removal.(3) The spatiotemporal distribution of nitrogen species, MLSS, COD/MLSS, COD/NOx-N, COD, NH3-N, NO3--N, NO2--N, TN and TP under the three typical working conditions in the intermittent aeration working mode of CIBR indicated that the whole reactor was in completely mixed flow in aeration and agitation phases and in plug flow in the settling phase. The sufficient aerating and anoxic agitating ensured the efficient denitrification. The continuous influent not only decreased the restraint of heterotrophic bacteria to the nitrobacteria under the aerobic phase, but also eased the negative effect of low influent C/N ratio on denitrification by supplying the carbon source for denitrification inthe anoxic phase. Efficient simultaneous removal of nitrogen and phosphorus in CIBR could be achieved under the intermittent aeration working mode.(4) The variation of parameters in CIBR were different from that in SBR due to the continuous influent. Three points for organic compounds degradation and nitrogen and phosphate removal can be obtained from the curves of DO/ORP/pH, dORP/dt and dpH/dt. They are the complete of organic compound degradation and the start of nitrification (point A), the end or pause of nitrification (point B), and the end of denitrification and the start of anaerobic phosphorus release (point C).(5) During the alternation of intermittent aeration and facultative biochemical process, nitrification and denitrification efficiency decreased, phosphorus release increased and effluent quality was often unstable. The chemical assistant intermittent aeration could accelerate the resumption of the phosphorus removal, but could not resume the removal of COD, NH3-N and TN in a short time. In CIBR under different working conditions with intermittent aeration, the average removal of COD, NH3-N, TN and TP were 76.40%, 82.33% 66.24% and 70.18%, respectively. In order to improve the treatment efficiency and to reduce the running energy consumption, the combined process of CIBR and wavy flow subsurface constructed wetland was developed to treat municipal wastewater. According to the, High efficiency and low energy consumption can be attained by adjusting the working condition of CIBR according to the seasonal variation of influent quality and the removal efficiency of ecological units. The optimal working conditions of CIBR process in each season were condition II(2-1-1), condition V(2-0-2), condition VIII(3-1-2) and condition VII(3-2-1), respectively. The effluent quality can stably reach standards of municipal wastewater treatment (GB18918-2002).(6) In order to reveal the mechanism for energy reduction in CIBR process, the energy balance black box model and exergy balance grey box model were established. The structure of energy consumption and energy efficiency in CIBR process were investigated. The distributing coefficient (λ) of exergy was used for the first time. The ratio of excess sludge and dissipation exergy can be conditioned to reduce the energy consumption based on the the requirement of sludge treatment unit of the municipal wastewater treatment plant. The specific exergy consumption conception was proposed. The aim of saving energy was to reduce the specific exergy consumption and to decrease the outside devoted exergy. The specific exergy consumption was more accurate and precise than the specific energy consumption, thermal efficiency, enthalpy efficiency and aim exergy efficiency. By the analysis of the specific exergy consumption and energy consumption, it can be concluded that the exergy consumption of the combined process was much less. Compared with A2/O process and Bardenpho process, the combined process could reduce 37.59% and 57.84% energy consumption, respectively. The high energy efficiency of the combined process was stem from the low energy consumption for the removal of nitrogen and phosphorus in ecological unit and the run of varied working conditions in CIBR.
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