Abstract Groundwater circulation wells provide an alternative source of geothermal energy to more commonly used shallow open two-well systems. Their efficiency and impacts on groundwater chemistry and microbiology have not previously been investigated. We have monitored newly installed and pre-existing systems over a two-year period. Monthly hydrochemical measurements and microbial qPCR analyses of circulated water showed no changes in the groundwater composition, at least as long as no oxygen entered. None of the systems showed any clogging or precipitation, even where the groundwater had a high ferrous iron concentration, which has previously been considered to be unsuitable for open geothermal systems.

中文翻译：

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地热利用地下水循环井及其对地下水水质的影响

摘要 地下水循环井为更常用的浅层开放式双井系统提供了替代地热能源。它们的效率和对地下水化学和微生物学的影响以前没有被研究过。我们在两年的时间里对新安装的和预先存在的系统进行了监控。循环水的月度水化学测量和微生物 qPCR 分析显示地下水成分没有变化，至少只要没有氧气进入。没有一个系统显示出任何堵塞或沉淀，即使地下水的亚铁浓度很高，这在以前被认为不适合开放式地热系统。