Study On Oxygen Filling Experimental Of Sewage Land Biological Filtration Treatment System

With the speeding up of urbanization in our country, a suitable measures to localconditions of the sewage treatment is urgently needed，which can improve waterenvironment of the small towns. Traditional sewage land treatment system possessesmany advantages, such as: convenient maintenance management, good puriifcationeffect and low construction and operating cost, moreover, it can realize the wastewaterreuse which could produce remarkable ecological environment beneift. So，it isespecially suitable for small towns that lack of drainage pipe networks and sewagetreatment systems. Moreover, the aerobic sewage land biological ifltration treatmentsystem is applied more and more widely, because it can overcome many defects oftraditional technology, such as, jamming easily and the internal hypoxia environmentmakes the poor denitriifcation effect as lacking of oxygen iflling system. Therefore，the further study on oxygen iflling technology is particularly important.The topic simulated aeration system of aerobic sewage land biological ifltrationtechnology, and the oxygen iflling test has been carried out with two kinds of aerators,A and B in the case of clear water by adopting blast aeration. It respectively studiedthe oxygen transfer rules and oxygenation performance of aeration equipment underthe absence of ifller and gravel packing conditions. By changing gas lfow，waterdepth and temperature, the experiment studied the inlfuence of oriifce distribution, airvelocity, aspect ratio and temperature on oxygenation performance. Then，the testfocused on investigating the following four indicators: the residence time of the air inthe water, oxygen transfer coeiffcient, oxygenation capacity and oxygen transferefifciency，and concluded the optimum running parameters of aeration equipment,which provided the theory basis for the practical application of this oxygen ifllingtechnology in small towns sewage land biological ifltration treatment system.The results show that: the residence time of the air in the water decreases withincreasing gas lfow and decreasing aspect ratio (the ratio of water depth and aerationequipment’s effective width). In the range of2.83~12m~3/h，with the increase oforiifce’s air velocity, oxygen transfer coefifcient and oxygenation capacity also increase, but they are not the simple linear relationship. When there is gravel packing,oxygen transfer efifciency of aerator A，B increases respectively before the vertex of6m~3/h,9m~3/h and decreases subsequently with rising air velocity. However, the trendis not obvious without packing, the oxygen transfer eiffciency decreases ifrstly, thenincreases slightly and decreases again at the turning point of9m~3/h. Within the scopeof0.75~1.25(1.5~2.5m water depth), with the increase of aspect ratio, oxygen transfercoefifcient declines, but oxygenation capacity and oxygen transfer efifciency increasegradually. When water temperature ranges from4°Cto25.2。C，oxygen transfercoefficient increases gradually, while the saturated dissolved oxygen decreases. At thesame time, with the rise of temperature, oxygenation capacity and oxygen transfereiffciency increase ifrstly, then decrease at the vertex of12°C.In addition, due to gravel packing’s functions of blocking，shearing and breakingbubble, oxygenation performance of the aeration equipment can be improved to agreat extent. When it comes to the inlfuence of oriifce air velocity on oxygenationperformance, the ampliifcation of aerators’ oxygenation capacity are71.8%~165.2%，43.2%~168.6%respectively compared with the packless, and the oxygen transferefficienc’ys relative increase are73.0%~166.6%，44.1%~169.5%. By studying theinlfuence of aspect ratio on oxygenation performance, it concludes that aerators’ Noincrease by150.5%~177.9%，162.5%~208.5%and E increase by151.1%~177.8%，162.3%~207.0%relative to packless.The optimal operating parameters of the aeration equipment are following: thegas lfow of9m~3/h，the aspect ratio of1.25(water depth is2.5m)，the water temperatureof11~13。C and the selection of aerator B. In this case，the higher oxygen transfercoefifcient, oxygenation ability and oxygen transfer eiffciency can be obtained.