Bioremediation of polluted soils via bioslurry reactors is an interesting option among those available nowadays, especially when recalcitrant pollutants are present. Vortexing unbaffled stirred tanks may be a valuable choice to this purpose as they were recently found to be more efficient than baffled vessels for solid suspension processes where mixing time is not a controlling factor. When operated at sufficiently high agitation speeds, the central vortex bottom reaches the impeller and air bubbles start to be distributed throughout the system, thus avoiding any sparger and related clogging issues. In the present work, a vortexing unbaffled stirred tank with solid loadings ranging from 2.5% w/w (weight of the solid/weight of the liquid) up to the very high 160% w/w was studied. Different turbine types including Rushton turbine, up- and down-pumping pitched blade turbines, and A310 were investigated. The minimum impeller speeds for complete particles’ suspension (N_js) and system aeration (N_cr) along with the relevant power (P_js, P_cr) and specific power (per mass unit) consumptions (ε_js, ε_cr) were assessed, in order to identify the geometrical configuration and operating condition providing the lowest power consumption. Results showed that the Rushton turbine and a solid concentration B of about 30% may be the most economically convenient arrangement to achieve system aeration and complete particles’ suspension at the same time inside the reactor.

中文翻译：

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涡旋非折流生物浆反应器中的能耗降低

通过生物泥浆反应器对污染土壤进行生物修复是当今可用的一种有趣的选择，尤其是在存在顽固污染物的情况下。为此，涡旋无挡板搅拌罐可能是一个有价值的选择，因为最近发现对于混合时间不是控制因素的固体悬浮工艺，它们比挡板罐更有效。当以足够高的搅拌速度运行时，中心涡旋底部到达叶轮，气泡开始在整个系统中分布，从而避免了任何喷头和相关的堵塞问题。在目前的工作中，研究了一种涡旋无挡板搅拌槽，其固含量为2.5％w / w（固体重量/液体重量）至非常高的160％w / w。不同类型的涡轮机，包括Rushton涡轮机，上，下泵距变桨叶涡轮和A310进行了研究。完整颗粒悬浮的最小叶轮速度（N _js）和系统通气（N _cr）以及相关功率（P _js ，P _cr）和比功率（每质量单位）消耗（_εjs，_εcr）进行了评估，以识别几何结构和运行条件提供最低的功耗。结果表明，Rushton涡轮机和固含量B约为30％可能是在系统内同时实现系统通气和完整颗粒悬浮的最经济方便的安排。