Removal of iron(II) from groundwater by aeration and rapid sand filtration (RSF) with the accompanying production of drinking water sludge in the preparation of drinking water from groundwater, and chemical well clogging by accumulation of hydrous ferric oxide (HFO) precipitates and biomass after mixing of oxygen containing and of iron(II) containing groundwater, are identical processes. Iron(II) may precipitate from (ground)water by homogeneous, heterogeneous and/or biological oxidation, where the contribution of these processes, and thus the characteristics of the corresponding HFO precipitates, is a function of pH and process-conditions. Under current conditions in drinking water treatment, homogeneous oxidation dominates above pH ≈ 7.75, and heterogeneous and biological oxidation below this value. In chemical well clogging, this transition occurs at pH ≈ 7.0. This information is relevant for the optimization of removal of iron(II) from groundwater by aeration and RSF and the corresponding quality of the produced drinking water sludge, and for the operation of wells clogging by accumulation of HFO precipitates and biomass.

通过曝气和快速砂滤（RSF）去除地下水中的铁（II），并伴随着饮用水污泥的产生，以从地下水中制备饮用水，以及由于含水三氧化二铁（HFO）沉淀物和生物质的积累而造成的化学井堵塞混合含氧地下水和含铁（II）的地下水后，是相同的过程。铁（II）可能通过均相，异质和/或生物氧化从（地下水）中沉淀出来，其中这些过程的贡献以及相应HFO沉淀物的特性是pH和过程条件的函数。在当前的饮用水处理条件下，高于pH≈7.75时，均相氧化起主导作用，低于此值时，异质和生物氧化起主导作用。在化学井堵塞中，这种转变发生在pH≈7.0时。此信息与通过曝气和RSF去除地下水中铁（II）的最优化以及所产生的饮用水污泥的相应质量以及因HFO沉淀物和生物质的积累而堵塞井的操作有关。