title: Practical removal of radioactivity from soil in Fukushima using immobilized photosynthetic bacteria combined with anaerobic digestion and lactic acid fermentation as pre-treatment.
abstract: Practical removal of radioactivity from polluted soil in Fukushima, Japan was done using a photosynthetic bacterium, Rhodobacter sphaeroides SSI, immobilized in alginate beads. The beads were put in a mesh bag and soaked in which soil was suspended (5 kg of soil/10 L of tap water). The radioactivity of the broth decreased by 31% after 15 d of aerobic treatment. When lactic acid bacterial culture broth was added to the suspend broth, about 50% of the radioactivity was transferred to a suspend broth fraction consisting of small particles from the soil after 3 d of fermentation and 20 s of sedimentation. The results suggest that organic matter in the soil was decomposed by anaerobic digestion and lactic acid fermentation simultaneously, and was then transferred into the liquid as small particles. With combined treatment by anaerobic digestion and lactic acid fermentation for 5 d and immobilized bead aerobic treatment for an additional 19 d, the radioactivity of suspend broth decreased by 66%. The radioactivity of the original soil (10.56 µSv/h) ultimately decreased by 67% (3.52 µSv/h) after the combined treatment.
authors.affiliation: Materials Science and Engineering, Graduate School of Engineering, Hiroshima Kokusai Gakuin University, 6-20-1 Nakano, Hiroshima 739-0321, Japan. sasaki@hkg.ac.jp
authors.forename: Ken
authors.initials: K
authors.lastname: Sasaki
authors.forename: Hiroyo
authors.initials: H
authors.lastname: Morikawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Kishibe
authors.forename: Kenji
authors.initials: K
authors.lastname: Takeno
authors.forename: Ayaka
authors.initials: A
authors.lastname: Mikami
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Harada
authors.forename: Masahiro
authors.initials: M
authors.lastname: Ohta
mesh_terms: D000332:Aerobiosis; D000464:Alginates / Q000737:chemistry; D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D018914:Cells, Immobilized / Q000737:chemistry / Q000378:metabolism; D002588:Cesium Radioisotopes / Q000302:isolation & purification* / Q000378:metabolism; D005285:Fermentation; D062406:Fukushima Nuclear Accident; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000378:metabolism*; D007777:Lactobacillaceae / Q000378:metabolism*; D008863:Microspheres; D010788:Photosynthesis; D012242:Rhodobacter sphaeroides / Q000737:chemistry* / Q000378:metabolism; D012987:Soil / Q000737:chemistry; D012990:Soil Pollutants, Radioactive / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D000464:Alginates; D002588:Cesium Radioisotopes; D006603:Hexuronic Acids; D012987:Soil; D012990:Soil Pollutants, Radioactive; D019344:Lactic Acid; D020723:Glucuronic Acid