Study Of CIBR-Constructed Wetland For Wastewater Reuse

As the conventional wastewater treatment has weak adaptive ability to the seasonal variation of water flow rate and quality, a biological / ecological self-responding combined technological process system, which is mainly composed of a biological reactor and an Wavy Subsurface Flow Constructed Wetland are combined, was proposed in this study. The updated and past research result of the biological reactor and ecological water treatment technology field has been considered into the design of this system. The biological reactor of this system is a continuous-flow integrated self-responding reactor, which integrates the traditional facultative biochemical techniques, intermittent aeration processes and the physico-chemical strengthen processes organically. This reactor can adjust the running mode based on the raw water quality, discharge standard and external environmental condition to low energy consumption and heighten the effect of the treatment as possible on the condition that the system must operated stably.This paper mainly studies the removal of COD, TN,ammonia nitrogen and TP in the reactor with different operation modes(2+2 mode and 2+1 mode) and in the Wavy Subsurface Flow Constructed Wetland, as well as their related removal load of the combinational wastewater treatment system. Moreover, the majior factors affecting the performance of the combined system have also been researched. We have to study an operating matrix too, based on the past research results.The major conclusions are summarized as follows:(1) The average removal efficiencies of COD,TN,ammonia nitrogen and TP under the first conditions were 86.56,88.76,92.27 and 74.72%, respectively. The average COD,TN,ammonia nitrogen and TP concentration of effluent under this condition were 14.73,3.79,2.01 and 0.94 mg/L, respectively. The average removal efficiencies of COD,TN,ammonia nitrogen and TP under the second conditions were 84.81,82.38,92.61 and 88.20%;The average COD,TN,ammonia nitrogen and TP concentration of effluent under this condition were 24.77,4.63,2.69 and 0.43 mg/L. The treatment performance of the tow combined system was good, and the effluence of them can attain the request of the national Water Quality Standard for Urban Miscellaneous Water Consumpution ( GB/T 18920-2002).(2) Concerning removal load of COD, ammonia nitrogen and TN, the reactor plays a more important role than the constructed wetland in the combined system, but as to the removal load of TP, the constructed wetland contributes more. After changing the packing of the constructed wetland, the average removal efficiencies of TP raised from 74.72% to 88.20%. The average TP concentration of effluent can meet the stringent regulations on effluent discharges (the first rank-A standard of GB18918-2002).(3) The major factors affecting the performance of the combined system were: the hydraulic retention time(HRT) of the reactor,the hydraulic loading rate(HLR) of the constructed wetland,water temperature,packing,concentration of inffluent, et al.(4) Based on the municipal wastewater characteristics in Wuhan City, we got the operating matrix of the combined system by adjusting the operating condition of CIBR. The effluent can reach the class I-A criteria specified in Discharge Standards of Pollutants for Municipal Wastewater Treatment Plants (GB18918-2002). The treatment energy consumption can be saved by 20. 77% and 40. 12%,respectively compared with A/A/O process and Bardenpho process.