巻号一覧
36 巻 (2000)
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36 巻, 1 号
選択された号の論文の6件中1～6を表示しています
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SHIGERU TAKEDA, SETSUKO KITAHARA, KEISUKE IWAHORI2000 年 36 巻 1 号 p. 1-7
発行日: 2000/03/15
公開日: 2010/02/26
ジャーナル フリーAn experimental investigation was carried out on removal characteristics of Verotoxin-free Escherichia coli O157: H7 in a batch culture of activated sludge and stored sludge, and then its profiles in a domestic wastewater treatment facility was discussed.
Domestic wastewater containing about 104CFU/ml of E. coli O157: H7 was treated by activated sludge (MLSS concentration was about 2, 500 mg/l) at 25°C. E. coli O157: H7 was almost completely removed from the supernatant after 8 hrs, and fecal coliforms and total coliforms were reduced considerably. Although the bacteria in the activated sludge mixed liquor decreased with aeration time, E. coli O157: H7 still survived after 24hrs. E. coli O157: H7 was almost all removed from the stored sludge after 30 days while for fecal coliforms and total coliforms it took up to 150 days for removal.
We proposed a case study model for E. coli O157: H7 removal in a middle-scale domestic wastewater treatment facility using the extended aeration process where the bacterial contamination occurs at the level of 104-105CFU/ml. The number of E. coli O157: H7 bacteria declines in the aeration tank during the 24 hr aeration period and is almost completely removed from the resulting biologically treated water. If 0.5% of influent is taken from the sedimentation tank as excess sludge, E. coli O157: H7 survives in this sludge at the level of 102-103CFU/ml. The bacteria in the sedimentary sludge increases by thickening but is almost completely removed during storage over a month.抄録全体を表示PDF形式でダウンロード (895K) -
SHUN'ICHI HONDA, NAOYUKI MIYATA, KEISUKE IWAHORI2000 年 36 巻 1 号 p. 9-14
発行日: 2000/03/15
公開日: 2010/02/26
ジャーナル フリーCellulose profiles in actual wastewater treatment plants were surveyed as a first step to use cellulose containing raw wastewater and sludge. Cellulose in primary sludge of separate sewer system was estimated to be contained more than that of combined sewer system, resulting in about 17w/w% per SS. Sludge sampling from primary sedimentation tank of separate sewer system was concluded to be most effective for recovery of cellulose. As a result of calculation, recovery amount of cellulose from wastewater treatment plants in Japan was estimated at about 400, 000 t in year. Therefore, potential biomass resources and energy were suggested to be contained in sludge of wastewater treatment plants in Japan.抄録全体を表示PDF形式でダウンロード (3044K) -
庄司 成敬, 井上 充, 西村 修, 稲森 悠平2000 年 36 巻 1 号 p. 15-23
発行日: 2000/03/15
公開日: 2010/02/26
ジャーナル フリーTo achieve stable removal of BOD, nitrogen and phosphorus, UF membrane process was combined with intermittent aeration sequencing batch activated sludge process (SBR process) . The effect of a hybrid system was studied comparing with that of a SBR system using bench scale plants.
Removal efficiencies of BOD and T-N in a hybrid system were higher than those in a SBR system, whereas removal efficiency of T-P was similar in both systems. In order to diminish UF membrane facility in size, a quadruple reactor type hybrid system was developed and it was successfully applied. A hybrid system was able to keep high removal efficiencies when the bulking of activated sludge occured. The flux of UF membrane was recovered by washing with 0.1N NaOH and 10% H2O2 solutions.抄録全体を表示PDF形式でダウンロード (1028K) -
横山 勝一, エルフィトリアナ , 白石 有里佳, 上村 芳三, 幡手 泰雄2000 年 36 巻 1 号 p. 25-31
発行日: 2000/03/15
公開日: 2010/02/26
ジャーナル フリーConcentrations of nitrate and nitrite in groundwater are increasing year after year because of permeation of fertilizers and livestock drain into the ground. These nitrogen species may cause methemoglobinemia, whose characteristic symptom is cyanosis. In this study, an immobilized denitrifying bacterium was used to remove such nitrogen species from water. Ion-exchange resin, reverse osmosis membrane, electrodialysis and biological processes are the representative denitrification methods. These methods except for biological treatment cause trouble with the drain water. In biological treatment, there are two choices; autotrophic and heterotrophic denitrification. In both cases, nitrate is reduced to nitrogen gas by the bacteria. Heterotrophic bacterium requires organic carbon as the nutrient. Existence of organic carbon is not acceptable for treating drink water. In this study an autotrophic bacterium was, therefore, chosen to avoid using organic carbon.
In this study, batch and continuous denitrifying experiments were carried out using Paracoccus denitrificans. The batch experiment was conducted in a 200ml-Erlemeyer flask containing 100ml of treating water and free or immobilized cells. The continuous experiment was carried out using a fixed bed bioreactor of 4.6cm internal diameter. In continuous denitrification, a packed bed of alginate-immobilized cells was used. In the continuous experiment, denitrification was successfully carried out for four hundred hours.抄録全体を表示PDF形式でダウンロード (887K) -
NORIO SUGIURA, OSAMU NISHIMURA, YUHEI INAMORI, NORIO IWAMI, RYUICHI SU ...2000 年 36 巻 1 号 p. 33-39
発行日: 2000/03/15
公開日: 2010/02/26
ジャーナル フリーIn this study, potential of biodegradation of musty odor producing Phormidium tenue by biofilm was examined. The biofilm was scraped from a honeycomb-like tube settled in the biological treatment facility of Kasumigaura Waterworks and P. tenue which produces 2-methylisoborneol (MIB) was isolated from Lake Kasumigaura. P. tenue of 80 mgl-1 and 103μgl-1 of the mllsty odor compound, MIB were degraded by the biofilm within 8 days. It was found that several protozoa such as Monas guttula, Holostica sp., Tetrahymena sp., and Stylonychia sp. in the biofilm actively predated on the P. tenue, subsequently the eluted MIB from the strains was perfectly assimilated by bacteria in the biofilm.抄録全体を表示PDF形式でダウンロード (2467K) -
河野 哲郎, 森 一博2000 年 36 巻 1 号 p. 41-46
発行日: 2000/03/15
公開日: 2010/02/26
ジャーナル フリーThe dark contrast microscopy, in which a dark image can be seen against somewhat bright background, is especially suited for examining details of biological specimens. However, objective lenses recently made in Japan for this purpose are designed at rather small values of transmission factor so as to obtain a sharp image especially with extremely thin specimens like animal cells. This caused another problem: the deterioration of phase contrast image with specimens which have rather thick optical path but can be clearly contrasted with short-barrel objective lenses once supplied. In this study, the authors tried to improve such image by mounting specimens with a liquid medium having refractive index larger than water so as to reduce the phase difference between specimens and the medium. Among various hydrophilic substances examined using Type 021N filaments as specimens, PVA was found to be most suited for this purpose. When filamentous bacteria in activated sludge are of concern, PVA solutions at different concentrations around 5%w/w to 15%w/w can be recommended on the basis of fact that the objective lens employed in this study has fairly a small value of transmission factor, and at the same time, there exist few filaments that have cells dimension greater than those of Type 021N in activated sludge.抄録全体を表示PDF形式でダウンロード (7795K)
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