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1、环境科学专业英语翻译专业:环境科学班级:0224121学号:022412111姓名:魏亚南3、Resultsanddiscussion3、结果与讨论3.1Flowvelocitydistributioninoxidationditch。Changeofflowvelocityhasacertainimpactonnitrogenremovalprocessoftheoxidationditch,withitsplug-floweffectandflowvelocityasthevariablestocontroltotalnitroge
2、nremovalefficiency[11].Flowvelocitycouldnotonlyaffectthesludgedeposition,butalsoaffectthehydrauliccycletimeoftheoxidationditch,theproportionoftheresidencetimeofaerobicandanoxicenvironment,dissolvedoxygen,organicmatter,andthedistributionofsludgeconcentrationdirectly.Inadd
3、ition,flowvelocitywasalsoadirectreflectionoftheextentofdisturbanceinthetrench,playinganimportantroleintheshapeandsizeofsludgeflocdirectly,whichwasthekeyfactoroftheoccurrenceofSNDprocessintheoxidationditch。3.1:氧化沟中的流速分布(SND:同步硝化反硝化)流速的变化对氧化沟的脱氮过程有一定的影响。在控制总氮的去除效率过程中,氧化沟中的
4、活塞流效率和流速是变量。流速不仅直接的影响污泥沉积,也直接影响氧化沟的水力循环时间,好氧和缺氧环境下停留时间的比例,溶解氧,有机物和污泥浓度分布,另外,流速也是氧化沟干扰程度的直接反映,在形成的污泥絮体的形状和大小上扮演重要的角色。污泥絮体在硝化和反硝化过程中是关键因素。AscanbeseenfromFig.3,flowvelocityoftheoxidationditchwasaffectedbytheaerationandthechangesofspatiallocationsignificantly,withtheaveragev
5、elocity(0.140m/s)inthetrenchofoperatingCondition2(openingfouraerationwheels)beinghigherthanthemeanvelocity(0.124m/s)inCondition1(withthreeaerationwheelsinoperation).Thevelocityvariationsinthehorizontalandverticaldirectionswerealsoobvious,withtheaveragevelocityatthebottom
6、,middle,upperpartbeing0.172,0.122and0.127m/s,whichweresignificantlyhigherthanthevalues(0.150,0.106and0.115m/s)underCondition1.Inthetwokindsofoperatingconditions,theflowvelocityinthefirstcornerandinsideofthecrosssection11waslowandthereshowedtheevidenceofsludgedeposition.O
7、verall,theflowvelocityinmostoftheregionsinthetwooperatingconditionsoftheoxidationditchwasintherangeof0.1−0.2m/s,withtheflowvelocityinmostofthebottomareagenerallymeetingtherequirementsofno-depositionflowvelocity(0.15m/s[12]).Thepowerdensity(18.87W/m3)inoperatingCondition1
8、wassmallerthanthatinoperatingCondition2(24.38W/m3)withlessenergyconsumption。从图3中可以看出,氧化沟中的流速明显受曝气和空间位置变