Thermosolutal transport in reservoirs generated by release and leaching of salinity and nutrients from anaerobic bed

在富营养化的水库中，在严重的厌氧条件下，高浓度的营养物质和离子物质从床上释放出来。由于浸出过程在床上产生高盐度或重水团，它在倾斜的床上重力产生倾斜的羽流，并将热量和质量输送到底层。这一过程可能会给底水带来严重的富营养化。为了预测由于热溶质输送而产生的热通量和质量通量，并设计相应的对策，本文对以下几个方面进行了研究。(1)针对厌氧底水的热盐度平衡，对某富营养化水库的水质进行了测量。(2)在试验模型中考察了从水库中采集的床料装入厌氧水后，床中盐分的释放通量。(3)利用微泡曝气系统进行了现场净水实验。(4)模型试验和a…为了研究浮力和流场，对倾斜的羽流进行了进一步的分析。主要发现如下。热溶对流是造成水库底水异常稠化、咸化的主要原因。由于盐度分层非常稳定，蓄水在过去许多年里从未被倾覆过。这会使底层水变得更加富营养化。是暖水从浅层到底层的羽流对流导致了底层的逆温层结。用羽流理论计算热流和质量流，并用实验数据进行了验证。将通量定律成功地应用于野外观测的热、盐平衡计算。研究发现，微泡曝气系统对促进垂直混合和底层曝气非常有用。开始曝气后，重的厌氧底层水团完全消失，水库完全被淹没，下一步需要开发一种考虑热溶解对流过程的水质预测工具。我们还应继续进行净水实验，以改进该系统，使其便于用户使用。较少

In eutrophic reservoirs, high concentration of nutrients and ionic matters are released from the bed under badly anaerobic condition. Since the leaching process produces high salinity or heavy water mass on the bed, it gravitationally generates an inclined plume on the sloping bed and transport heat and mass to the bottom layer. This process may bring serious eutrophication of bottom water.In order to predict heat and mass flux due to the thermosolutal transport and device a countermeasure against this, the following were examined. (1)Focusing on heat and salinity balance in the anaerobic bottom water, a water quality measurement was performed in a eutrophic reservoir. (2)Release flux of salinity from the bed was examined in an experimental model in which the bed materials sampled from the reservoir were installed in a tank and filled with anaerobic water. (3)Using a micro-bubble aerator system, an in-situ experiment of water purification was carried out. (4)A model experiment and an a … More nalysis on the inclined plume were performed in order to investigate buoyancy and flow fields.The main findings are as follows. The thermosolutal convection is the main reason of making the reservoir bottom water to be extraordinary heavy and salty. Because of its very stable salinity stratification, the impounded water has never been overturned in the last many years. It makes the bottom water to be more seriously eutrophicated. It is the plume convection of warm water from the shallow layer to the bottom layer that is responsible for producing an inverse temperature stratification in the bottom layer. The heat and mass flux can be computed by the plume theory which was verified with the experimental data. The flux law was successfully applied for computing heat and salinity balance observed in the field survey. The micro-bubble aeration system was found to be very useful for promoting vertical mixing and aerating the bottom layer. After starting the aeration, the heavy and anaerobic bottom water mass was completely disappeared and the reservoir was fully overturned.The next step we should take is to develop a prediction tool of water quality by considering the thermosolutal convection process. We should also continue the water purification experiment for improving the system to be of user-convenience. Less