| This paper aims at South-to-north Water Diversion Project water source area scattered across different towns, difficulty to collect centralized sewage treatment and the gap between large of effluent standards and water quality. Tourism and catering industry is developing rapidly in water source area, but economic development of small towns is still lagging, drainage and sewage treatment facilities are not up to the standard, resulting in a large number of domestic sewage and garbage being disposed of directly into the river. This has posed threat to the water sources, quality and safety of water.This paper relies on policies presented in "twelfth Five-Year Plan" water pollution control technology by taking major projects such as Water security Hubei Han Ku catchment basin using key technology research and demonstration topics (2012ZX07205-002) and selected water source area of Bai-er River of Sheng-ding River upstream as case studies. These two cases involve native ecosystems, as well as ecological system. This paper will then launch small scale test and demonstration project for effective treatment of sewage and ecological restoration of river in water sources area.On small scale test, The farmhouse waste water was treated by the bacteria-algae biofilm system, which covered over combined packing and elastic packing. The results show that, two kinds of bacteria-algae biofilm system had a good removal efficiency of COD, NH3-N, TN and TP. The bacteria-algae biofilm system of combined packing for COD removal was more significant, the highest removal efficiency was 94.8%. The algae-bacterium bio-film system of elastic packing for NH3-N, TN and TP removal had more prominent, the highest removal efficiency was 94.7%、93.6% and 91.3%. After comprehensive consideration, the bacteria-algae biofilm system of elastic packing had certain advantage in treatment local farmhouse wastewater, and the treatment effect is stable.The experiment of treating the towns wastewater in pilot-scale demonstration project shows that, the COD, NH3-N, TN and TP average removal rates of constructed rapid infiltration were 47.54%,49.89%,48.77% and 60.11%. When the HRT is 6.3 hours, the COD, NH3-N, TN and TP average removal rates of horizontal subsurface flow wetland were 42.66%,41.19%,40.97% and 50.15%; When the HRT is 12.6 hours, the COD, NH3-N, TN and TP average removal rates of horizontal subsurface flow wetland were 46.91%, 43.41%,43.85% and 51.77%. When the HRT is 9 hours, the COD, NH3-N, TN and TP average removal rates of surface flow constructed wetland were 45.97%,38.01%,28.56% and 27.36%; When the HRT is 18 hours, the COD, NH3-N, TN and TP average removal rates of surface flow constructed wetland were 48.11%,39.81%,30.19% and 29.67%. When the HRT is 22.5 hours, the COD, NH3-N, TN and TP average removal rates of ecological floating island were 46.32%,28.59%,19.53% and 23.99%; When the HRT is 45 hours, the COD, NH3-N, TN and TP average removal rates of ecological floating island were 48.11%,39.81%,30.19% and 29.67%. When the HRT is 18 hours, the COD, NH3-N, TN and TP average removal rates of the super-micro bubble aeration-bacteria-algae biofilm system of elastic packing were 51.54%,41.49%,33.51% and 18.03%; When the HRT is 36 hours, the COD, NH3-N, TN and TP average removal rates of the supermicro bubble aeration-bacteria-algae biofilm system of combined packing were 56.25%,41.95%, 36.88% and 23.00%.Even though there was influent concentration of fluctuations, it has a good removal of COD, TN, NH3-N, TP; Indicate intensifying iron, zeolite, other reaction packings, and layered cloth type set had a good removal of COD, NH3-N, TP. Among them wood chips such as sustained that releases carbon plays a significant role of improving TN the removal rate and denitrification.Horizontal subsurface flow constructed wetland,for the removal of COD, TN, NH3-N, TP, the HRT is 6.3 hours better than HRT is 12.6 hours; Surface flow wetland relative to horizontal subsurface flow constructed, it does not have good removal to pollutant. In general analysis the HRT is 9 hours better than HRT which is 18 hours; Ecological floating island has a good removal to COD, but the general removal of N and P.The super-micro bubble aeration- bacteria-algae biofilm system has a good removal of COD, TN, NH3-N, TP. The water of COD and TN reach four class of "system Surface Water Quality Standards" (GB 3838--2002), the water of NH3-N and TP reach three class of "system Surface Water Quality Standards" (GB 3838--2002).From the analysis the influencing factors of super-micro bubble aeration-bacteria-algae biofilm system, it shows that temperature has some effect on TN, This can be explained that metabolism of microbial biofilms related to temperature, after lowering the water temperature, microbial growth is inhibited, decomposition slows the absorption of pollutants, and then make the removal of N of bacteria-algae biofilm system decreased.To elastic packing, the bacteria-algae biofilm system of combined packing for COD removal had more significant, but the bacteria-algae biofilm system of elastic packing for TN, TP removal better than bacteria-algae biofilm system of combined packing. With the HRT more increase,the better effect of TN, TP, this show, to high nitrogen of wastewater, bacteria-algae biofilm system has a good effect of increase HRT.To ensure that the sewage flows into the river to reach South-to-north Water, there have to be some requirements for diversion Project water source area quality. Research shows that multiple artificial strengthening ecological buffer zone pollution reduction technology, also important significance for water safety. |
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