Abstract
The well efficiency sometimes declines because of the damages of the riser pipes and/or screens, or the clogging of screens with scale. From the viewpoint of microbiology, this study is conducted to explain the troubles exemplifying the well located in Fukui plain.
The formation of Fukui plain mostly consists of alternating beds of clay and gravel, and the groundwater is collected from three aquifers. The groundwater samples obtained from different depths were analyzed. The suspended matters were observed by differential interference microscope and episcopic fluorescence microscope.
The coexistence of some iron bacteria suppresses clogging of screens and the propagation of specific species occurs corrosion of screen. The groundwater quality and the condition of iron bacteria propagation varies depending on their aquifers. It is clarified that symbiosis of iron bacteria and propagation of specific iron bacteria causes different types of well obstacles.
