| According to the reactor theory, our research team applied the characteristic of spiral up-flow to the wastewater treatment technique and conducted a new reactor for wastewater treatment —–spiral up-flow reactor (SUFR). The dissertation carried out a research on the treatment of municipal wastewater using SUFR system. The conclusion was as follows:(1) The SUFR-A/O biological phosphorus removal system could obtain high removal efficiency of phosphorus and COD. When the influent concentration of COD and total phosphorus (TP) was in the range of 212~498mg/L and 3.62~8.64mg/L respectively, the effluent concentration of COD and TP was below 40mg/L and 0.5mg/L respectively, and the removal efficiencies of COD and TP were kept over 95% and 96% respectively. This SUFR-A/O system had characteristics of simple configuration, high and stable efficiency, and was very applicable to the treatment of wastewater that was not strict for the TN concentration.(2) The SUFR biological nitrogen and phosphorus removal system could obtain high removal efficiency of nitrogen, phosphorus and COD. The SUFR biological nitrogen and phosphorus removal system could ensure the effluent concentration of COD, TN and TP was in the range of 8~31mg/L, 2.3～9.3mg/L and 0.07～0.49mg/L respectively, and the removal efficiency of COD, TN and TP was kept over 94%, 86% and 96% respectively. According to the experimental results, the optimizing parameters of the SUFR biological nitrogen and phosphorus removal system were: (a) The ratio of the volume among the anaerobic, anoxic and aerobic reactor was 1:1.5~2.5:3~3.5, the ratio of the sludge in the aerobic reactor among the total sludge was over 47%, the ratio between the height and the diameter of every reactor was 4~6. (b) The hydraulic retention time (HRT) was 8~10 hours, the sludge retention time (SRT) was 15~22 days, the dissolved oxygen (DO) in the downside of the aerobic reactor was remained as 0.5~0.95 mg/L, in the middle and upside of the aerobic reactor was 3.0~3.5 mg/L. (c) The recycled sludge from clarifier to anoxic reactor was 40%~60% of the influent rate, the internal recycled mixed liquor from aerobic to anoxic reactor was from 250% to 300% of the influent rate, and the recycled mixed liquor from anoxic to anaerobic reactor was 100%~150% of the influent rate.(3) The characteristic of spiral up-flow could form a higher variety of ecological niches available for bacteria with different growth requirements, thus the diversity of microorganism population in the SUFR system was complex, which made the SUFR system had a higher ability of self-instauration and resisting outsider interference. The characteristic of spiral-flow could make it easy to form granular sludge, and benefited to produce the interlaced area with different tiny environmental conditions, which was beneficial to the existence of denitrifying phosphorous removal bacteria and made it easy to realize the current difficult engineering process of denitrifying dephosphatation. At the same time, the formation of granular sludge would benefit simultaneous nitrification and denitrification in the aerobic reactor. Therefore, using the SUFR system could achieve high removal efficiency of phosphorus and nitrogen under relatively lower C/(N+P) ratio, and solved the limited organic substrate problem existed in conventional wastewater treatment of biological phosphorus and nitrogen removal process. The characteristic of spiral up-flow was favorable to enhance gradient distributing of the substrate, prolong the retention time of the substrate in the reactor, and made the SUFR be similar to plug-flow reactor and could increase the capacity utilization of the reactor.(4) The special shearing force of the spiral up-flow could destroy the detained membrane around the bubble, decrease the thickness of the water membrane, and thus decreased the resistance of transference; furthermore, the centrifugal inertial effect of the spiral up-flow could make the activated sludge and the organic matter move radically, so had a retardant force for...
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