The Study Of Mid-term Biological Pre-treatment For The Source Water Of Qingdian Lake

At the water intake ,the YDT elastic space Packing is used in Purify the eutrophic Qingdian Lake water of Shaoxing city.This study evaluates the effects of the kind of treatment process,in order to the feasibility study of the packing using in biological pre-treatment in actual project, and the most suitable applying conditions are certained by this study. The main results of study are bellow:(1) YDT elastic space Packing has all aspects effects on purifying the source water,When the 20℃-30℃ water temperature velocity is 4m/h, (a retention time of 1.75h),without aeration,The removal efficiencies are about 12.66%, -9.52%, 66.74% and 34.23% for COD_Mn, NH₄⁺-N, JTU for turbidit and degree for colority; under the aeration, the air-water ratio is 0.5:l,The removal efficiencies are 17.86%, 83.35%, 67.49%, 69.38 and 44.78%, for COD_Mn, NH₄⁺-N, Chla , JTU for turbidit and degree for colority.(2) The real effect the Hydraulic load does for the effect of water biological pre-treatment by elastic packing.depend on the different project. The removal of NH₄⁺-N is affected greatly, but the very little effect on turbidity. The analysis illustrates that there is unfavorable to high water quality when the hgdraulic load raising. According to the experiment, it is reasonable to assume 4m/h as the velocity.(3) Water tamperature has more influences to the removal efficiencies of COD_Mn, Chla. JUT for turbidity and degree for colority, but does little affect to the removal of NH₄⁺-N. As the water temperature raising, the removal of COD_Mn,Chla. > JTU for turbidity and degree for colority will be high.(4) By the observation and analysis for biological treatment, the main mechanism of removing algae by biological treatment is researched at first step.(5) It is can be decided by various requirements,whether or not the aeration will be taken. Under the aeration,the adviced suitable runing parameter as follows: Hydraulic retention time is selected 1.75h (conditions of a velocity is 4m/h),usually the air-water ratio is selected 0.5:1,in the winter it is selected 1:1.Innovative view points: To carry directly pretreatment in the water source's water intake, not taking the land, not increasing the pretreatment construction all has the application prospect in the technology and the economical aspect.