Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
J Environ Sci (China). 2018 Nov;73:9-19. doi: 10.1016/j.jes.2017.12.021. Epub 2018 Jan 10.
Thermal stratification is a common phenomenon in lakes and reservoirs and has a significant influence on water quality dynamics. Heihe Reservoir is a canyon-shaped reservoir in Shaanxi Province with strong thermal stratification. Therefore, eight water-lifting aerators (WLAs) were installed in this reservoir, which could overcome thermal stratification and increase oxygenation with gas flows between 20 and 50m/hr, and oxygenate the hypolimnion with gas flows less than 20m/hr. To examine the destratification efficiency of the WLA system, we used a three-dimensional hydrodynamic module based on MIKE 3 to simulate the thermal structure of Heihe Reservoir and compared the simulations with measured data. Results showed that operation of the WLA system promoted water mixing and effectively oxygenated the hypolimnion. Through the established energy utilization assessment method, the energy utilization efficiency of the WLA system was between 5.36% and 7.30%, indicating the capability of the technique for destratification in such a large reservoir. When the surface water temperature dropped to the theoretical mixed water temperature calculated by the energy utilization assessment method, reducing gas flow could save energy. This would prevent anaerobic conditions from occurring in the bottom water and maintain good water quality in Heihe Reservoir.
热力分层是湖泊和水库中常见的现象，对水质动态有重大影响。黑河水库是陕西省的一个峡谷型水库，具有很强的热力分层。因此，在该水库中安装了 8 台水力提升曝气机（WLA），可以克服热力分层，通过 20-50m/hr 的气体流量增加氧气供应，并通过小于 20m/hr 的气体流量对低氧层进行增氧。为了检验 WLA 系统的分层消除效率，我们使用了基于 MIKE 3 的三维水动力模块来模拟黑河水库的热力结构，并将模拟结果与实测数据进行了比较。结果表明，WLA 系统的运行促进了水的混合，并有效地对低氧层进行了增氧。通过建立的能量利用评估方法，WLA 系统的能量利用效率在 5.36%-7.30%之间，表明该技术在如此大的水库中具有分层消除能力。当表层水温降至能量利用评估方法计算的理论混合水温时，降低气体流量可以节约能源。这可以防止底部水出现厌氧条件，并保持黑河水库的良好水质。
