| As for traditional subsurface flow constructed wetlands for wastewater treatment load is low, and the treatment effect influenced by the temperature, biological contact oxidation process and improvement of subsurface flow wetland combined process were adopted to treat with high concentration waste water in normal temperature and low concentration waste water in low temperature. Optimized to improve the constructed wetland hydraulic parameters, reported the characteristics and law of horizontal and vertical subsurface flow constructed wetlands to remove pollutants. In addition, researched the horizontal subsurface flow constructed wetland substrate at different depths within the distribution of pollutants and the reoxygenation effect of natural reoxygenation tank. Based on the construction of complex subsurface flow constructed wetlands, composite subsurface flow constructed wetlands with different water at room temperature and low temperature removal of pollutants were researched. Combined with the experiment results, reaction kinetics and hydraulic characteristics of complex subsurface flow wetland were discussed, and the kinetic parameters were calculated. According to the characteristics of biological oxidation and complex subsurface flow wetland, the wastewater treatment conditions for biological oxidation and complex sequence of different combinations of subsurface flow constructed wetlands was proposed and verified in the process of pilot test.Test of complex subsurface flow wetland showed that the optimal hydraulic retention time should not more than 96h, or the removal of pollutants will fall; complex subsurface flow constructed wetlands can effectively improve hydraulic loading rate of the wetlands. Normal temperature season could be increased 35%; low temperature season could be increased by 25%; increasing the volumetric loading rate can improve pollutant removal rate, when the COD, TP, TN and NH3-N volumetric loading rate are at the range of (5 ~ 70) g ? m-3 ? d-1, (0.05 ~ 0.65) g ? m-3 ? d-1, (0.5 ~ 7.5) g ? m-3 ? d-1 and (0.25 ~ 4.5) g ? m-3 ? d-1 respectively, the removal rate and the VLR show obvious took on linear relationship; Reflux has a obvious effect to improve pollutant removal efficiency of pollutants, but has a small impact of SS and TP. When R = 0.5, the removal efficiency of SS and TP could get the peak, the removal rate of COD, NH3-N and TN were relatively higher, which could get the peak when R = 1.0 If the corresponding reflux ratio continues to increase, then the removal rate started to decline; complex pollutant removal characteristics of the complex wetland showed that subsurface flow constructed wetland flow pattern close to plug-flow state.The test of bio-contact oxidation pre and post group technology which based on complex subsurface flow wetland showed, the pre-process can be used in the condition of high concentration of pollutants in the influent and effluent TN and NH3-N couldn't meet the criteria. The post-process is suitable for the condition of pollutant concentration is not high, but low temperature, the effluent TN and NH3-N could not meet the criteria. The two processes can solve the low efficiency problem when the nitrogen concentration was higher and wetlands at low temperature. In normal temperature and low temperature season, effluent data can meet the "Municipal Wastewater Treatment Plant Pollutant Emission Standards" (GB18918-2002) the 1st B emission standards; reflux ratio and the gas water ratio are the important hydraulic conditions which affect the post-process of bio-contact oxidation, the reflux ratio on the impact of the removal of pollutants was even more significant, recommended reflux ratio is R = 1.0; the gas water ratio on the removal of NH3-N has a significant effect, but with high energy consumption, recommended gas water ratio was 4:1; biological contact oxidation on the front have a higher COD removal rate, but cannot achieve full use of wetland function, resulting in high energy consumption; while biological contact oxidation post-process can achieve full use of the wetland function, only in low season on the NH3-N and TN removal were enhanced, low energy consumption.Productive experiments indicated that on the condition that the average temperature is 8.6℃, flooding water COD :(128-203) mg·L-1,NH3-N:(4.83~23.88 )mg·L-1,TP:(1.08~7.29) mg·L-1,SS:(89~106 )mg·L-1, retention time of biological contact oxidation combined process in hydraulic is 72h, hydraulic load is 150cm?d-1, reflux ratio of activating biological contact oxidation is 100%, activating chemical dephosphorization ,dosage of PAC is 10mg?L-1, effluent quality indexes can achieve the urban sewage treatment plants standards for pollutants discharge (GB18918-2002), 1st A standard.
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