微孔曝气作用下过饱和溶解气体的释放特性研究

Study on the Release Characteristics of Supersaturated Dissolved Gases Under Microporous Aeration

水温上升、光合作用、高坝泄流等过程均可能产生溶解气体过饱和问题,会影响河流和其他水体中鱼类的生物多样性。曝气技术已被证实能够显著促进过饱和TDG(total dissolved gas)、DO及DN等气体的释放,是一种减缓过饱水体影响的重要方法。使用针孔曝气盘和微孔曝气管进行了不同曝气量、曝气水深条件下的过饱和溶解气体释放试验,探究过饱和溶解气体释放规律。试验结果表明微孔曝气作用下过饱和TDG、DO及DN的释放过程符合一阶动力学方程,所有试验工况的过饱和DO能够释放到平衡状态,而过饱和DN的释放速率缓慢,且长时间无法达到平衡状态,呈现k_(DO)>k_(TDG)>k_(DN);过饱和TDG、DO及DN的释放系数随曝气量的增加而增加,随曝气水深的增加而减小,相同曝气量、曝气水深下使用微孔曝气管对过饱和TDG、DO及DN的释放效果是明显优于针孔曝气盘的。使用二元线性回归模型建立了微孔曝气作用下过饱和TDG、DO及DN的释放系数关系式,能较好地预测kTDG,相关系数R2达到0.958。研究揭示了微孔曝气作用下过饱和溶解气体的释放特性,为曝气技术减缓过饱和溶解气体影响提供一定的参考价值。

The processes of rising water temperature,photosynthesis,and high dam discharge may all cause the problem of supersaturated dissolved gas,which can affect the biodiversity of fish in rivers and other water bodies.Aeration technology has been proven to significantly promote the release of supersaturated TDG,DO,and DN,and is an important method for mitigating the impact of supersaturated water bod⁃ies.This article conducted experiments on the release of supersaturated dissolved gas under different aeration rates and water depths using pinhole aeration discs and microporous aeration pipes,exploring the release laws of supersaturated dissolved gas.The experimental results show that the release processes of supersaturated TDG,DO,and DN under the action of microporous aeration conforms to the first-order dy⁃namic equation.All supersaturated DO under experimental conditions can be released to an equilibrium state,while the release rate of super⁃saturated DN is slow and cannot reach an equilibrium state for a long time,showing k_(DO)>k_(TDG)>k_(DN);The release coefficients of supersaturated TDG,DO,and DN increase with the increase of aeration volume,but decrease with the increase of aeration depth.The release effect of su⁃persaturated TDG,DO,and DN using microporous aeration pipes is significantly better than that of pinhole aeration discs under the same aeration volume and aeration depth.A binary linear regression model was used to establish the release coefficient relationships of supersatu⁃rated TDG,DO,and DN under microporous aeration,which can effectively predict kTDG with the correlation coefficient of 0.958.This study reveals the release characteristics of supersaturated dissolved gases under microporous aeration,providing certain reference value for aera⁃tion technology to mitigate the impact of supersaturated dissolved gases.