Development of Hybrid Arsenic Removal Filter Using Iron

1. 铁细菌除砷特性：假设孟加拉国地下水的化学成分，利用合成地下水进行实验，铁细菌将亚铁氧化为三铁，提高了对砷的去除效率（III）。另一方面，砷（III）直接氧化为砷(V)也没有得到证实。由于在孟加拉国的井水过滤器中检测到铁细菌，因此建议采用铁细菌除砷方法在孟加拉国适用。混合式除砷工艺建议：虽然考察了金属铁柱除砷，但在过滤初期性能下降，亚铁从金属铁中洗脱出来。为此，研究了铁细菌柱与金属铁柱连接的系统除砷性能。按铁菌+金属铁的顺序，除砷效果较好，但有亚铁向出水流出。另一方面，以金属铁+铁菌为序，可以阻止亚铁的流出，具有较好的除砷效果。一种除砷过滤器的适用性检验：为了推荐合适的铁混合型除砷剂，对已引进孟加拉国农村的现有过滤器的状况和存在的问题进行了调查。有必要引进可在当地制造和修理的廉价的简单过滤器，同时开展社会发展活动。

1. Arsenic removal characteristics by iron bacteria : Iron bacteria oxidized ferrous iron to ferric iron and increased the removal efficiency of arsenic(III) in the experiment using synthesized groundwater supposing the chemical ingredient of the groundwater in Bangladesh. On the other hand, the direct oxidization of arsenic(III) to arsenic(V) was not confirmed. Because iron bacteria were detected in the filter of well water in Bangladesh, it was suggested that the arsenic removal method using iron bacteria was applicable in Bangladesh.2. Proposal of hybrid type arsenic removal process : Although the arsenic removal by a metal iron column was checked, the performance decreased at the early stage of the filtration and ferrous iron was eluted from the metal iron. Therefore the arsenic removal performance was examined in the system to which the iron bacteria column and the metal iron column were connected. In order of iron bacteria + metal iron, although removal of arsenic was good, the outflow of ferrous iron to effluent water was detected. On the other hand, in order of metal iron + iron bacteria, the outflow of ferrous iron was stopped with a good performance of arsenic removal.3. Examination of the applicability of an arsenic removal filter : In order to recommend suitable iron hybrid type arsenic removal, the condition and the issues of the existing filter which had been introduced into the farm villages in Bangladesh were investigated. It was necessary, to introduce the inexpensive simple filter that could be manufactured and repaired there accompanied with the introduction of social development activities.