Research On Combined Technique Of Water-lifting Aeration And Bio-contact Oxidation Proeess For Water Quality Improvement

At present, the focus of research and application is the water quality improvement and water in situ bioremediation technology. It sets purifying facilities by water’s own space, and the water gradually purified facilities under the action of natural push flow, mkes it purify and improve. This kind of technology investment provinces, and low energy consumption.The combined technique of water-lifting aeration and bio-contact oxidation proeess is a new type of water quality in situ repair improvement techniques, have energy-saving, cleaning, quick effect, etc. It is in allusion to natural micro-polluted water, water quality improvement high dissolved oxygen low oxygen demand, with the characteristics of pulse aeration increase water dissolved oxygen and mixed water circulating water, promote the continuous reforming with smaller for gas source, generate short-term pulse aeration, not only guarantees biological contact oxidation of oxygen, and provides the needed in the short inside produce larger aeration strength, security hydraulic hybrid conditions, meet the slightly polluted water conditions for biological contact oxidation of dissolved conditions and hydraulic conditions, save the energy.This paper firstly to pulse aeration biological contact oxidation method for the water quality improvement and the feasibility of research, optimize the operation parameters. Then, based on the water-lifting aeration produce pulse aeration, and biological contact oxidation combination, develop shallow water conditions importance aeration and biological contact oxidation combined device, and by mesocosm experiments verify the micro-polluted water quality improvement device effect. The main research results are as follows:1)The experiment proved that pulse aeration biological contact oxidation treatment micro pollution source water is feasible, in the protection of water dissolved to premise no less than4mg/L, pulse aeration biological contact oxidation treatment effect and continuous aeration biological contact oxidation quite. In pulse aeration strength and continuous aeration strength of the same case, the pulse aeration biological contact oxidation uses average oxygen can reduce80%, and save60%～80%air volume than that of continuous aeration.2) The study use Yangzhuang River of YangZhou as the object, actual measured the water treatment effect under different parameters conditions of ratio of without aeration time to aeration time、pulse period、hydraulic retention time and Bio-media,ect. As a result, pulse aeration biological contact oxidation applicable design parameters is aeration intensity4m3/(m2-h), ratio of without aeration time6:4～8:2, pulse period lmin-2min, process-time2h, uses combination packing. the the average removal rate of NH4+-N and CODMn achieved73.09%～93.58%and21.12%～24.29%, respectively,.3)According to the theory technology and experimental research, we determined the operation mode of the combined technique of water-lifting aeration and bio-contact oxidation proeess. The Bio-media is upside, and the water-lifting aeration is downside. The whole process system consists of water-lifting aeration, gas collection room, gas distribution system, bio-media, packing stents and buoy. Gas pipe and Bio-media around the center water-lifting aeration with a radiation shape. Some gas into water-lifting aeration produced gas-bullet, to push the water provide cyclic flow, make the far away micro pollution water pump and distribution to packing area, and another part gas produced pulse aeration to supply packing area needed for biological contact oxidation, and make packing area of perturbation, promote biofilm already so fall update, makes full use of the gas chamber the space, also can assure water treatment effect.4) We do this experiment at lotus pond park in YangZhou, the experiment show that biological contact oxidation and water-lifting aeration technology is feasible and efficient. Combining with engineering needs, determine the design parameters of the portfolio device used combination packing, perforated aeration way, aeration intensity 4m3/(m2-h), ratio of without aeration time9:1, pulse period30s, mesocosm area of about350m2, within mesocosm about2m, water volume depth about700m, packing area of47.1m2, packing highly1.4m, packing area65.94m3volume. During the experimental test, the water temperature is11.8℃～18℃, dissolved oxygen is outside the mesocosm2.14～4.92mg/L, dissolved oxygen within the mesocosm is2.97～6.56mg/L, and water dissolved oxygen within the mesocosm under the action of the portfolio device rise gradually over time, and tend to stable, fluctuation water mixing, meet the needs of the biological contact oxidation, the closer water-lifting aeration position, the higher the dissolved oxygen.5) The portfolio device static experiment played a good effect when water temperature under the conditions of15℃. Each test points after24h、48h、72h、96h the averageremovalrate of NH4+-N achieved24.70%,69.65%,76.07%,80.72%, respectively. The average removal rate of CODMn achieved14.84%,9.04%,9.3%,2.45%, espectively, and the average removal rate of TN achieved12.84%,18.70%,21.92%,29.40%, respectively, with the time pasted, water treatment effect also gradually getting better, after reaching limits to moderate.6) The portfolio device dynamic experiment shows that, water temperature below15℃, hydraulic retention time is about1.88h, the portfolio device average removal rate of NH3-N can still achieved55.31%, even best78.44%. Tests later become stable in basic maintain removal is around45%, the average removal rate of CODMn achieved9.98%, and average removal rate of TN achieved17.95%, water treatment effect is good.