水環境学会誌
Online ISSN : 1881-3690
Print ISSN : 0916-8958
ISSN-L : 0916-8958
27 巻, 4 号
選択された号の論文の6件中1~6を表示しています
原著論文
  • 新田見 匡, 山崎 恵美, 佐藤 弘泰, 味埜 俊, 伊藤 公夫, 三木 理
    2004 年 27 巻 4 号 p. 249-254
    発行日: 2004/04/10
    公開日: 2008/01/22
    ジャーナル フリー
    We analyzed denitrifying bacterial population dynamics in two wastewater treatment plants. For analyzing the population dynamics, we applied the PCR-DGGE method for targeting nirS genes, which code cytchrome cd1-type nitrite reductase. One plant treats Coke-oven wastewater (CW) and the other treats synthetic wastewater (SW) such as CW. The CW and SW mainly contained phenol, thiocyanic ion (SCN-) and thiosulfuric acid (S2O3-), and the 2 plants were configured with anoxic and aerobic tanks, respectively. Bacteria in the plants could denitrify using phenol, SCN- and S2O3- as electron acceptors. By analyzing nirS genes in the plants for a few months, we determined the partial denitrifying bacterial population in the plant and deduced bacteria that actually denitrify using phenol, SCN- and S2O3-. As far as we know, this is the first study on the analysis of the bacterial community in a CW treatment plant.
  • 庄司 仁, 佐藤 弘泰, 味埜 俊
    2004 年 27 巻 4 号 p. 255-260
    発行日: 2004/04/10
    公開日: 2008/01/22
    ジャーナル フリー
    Denitrifying polyphosphate-accumulating organisms (DN-PAOs) in the biological phosphorus removal process treating municipal wastewater were studied. On the basis of the ratio of anoxic phosphate uptake rate (PUR) to aerobic PUR, it was suggested that the minimized aeration for mixing the anaerobic tank is fatal to DN-PAOs even if the dissolved oxygen concentration was nearly equal to zero. The results also suggested that DN-PAOs preferred the anoxic followed by anaerobic conditions although they could be significantly observed in the processes without anoxic conditions. Moreover, the ratio serves as one of the parameters of the activated sludge model No.2d (ASM2d). From the sensitive analysis of the parameter in an A2O process, we could conclude that the phosphorus removal ability depended on the ratio of DN-PAOs. On the other hand, it did not affect the nitrogen removal ability (both nitrification and denitrification) very much. The parameter observed in the present experiments showed that we had to calibrate or measure it in each plant for the valid simulation of simultaneous nitrogen and phosphorus removal systems based on the ASM2d.
  • 小野(伊津) 恭子, 山本 和夫, 中島 典之
    2004 年 27 巻 4 号 p. 261-266
    発行日: 2004/04/10
    公開日: 2008/01/22
    ジャーナル フリー
    Sixteen different operational conditions of a photobioreactor for both organic wastewater treatment and material recovery were examined to determine the optimal condition(s) for the proliferation of purple nonsulfur bacteria (PnSB). Bacterial community changes were analyzed by denaturing gradient gel electrophoresis (DGGE) and fluorescence in situ hybridization (FISH). FISH was applied to detect PnSB and quantify their population. FISH results revealed that a high PnSB ratio was obtained under the conditions that deprivation of dissolved oxygen and restraint of oxygenic phototrophs were required. An infrared filter effectively suppressed oxygenic phototrophs and enhanced PnSB. Higher PnSB ratio was obtained at a low light intensity (260 lux and 650 lux) than at a high light intensity (5800 lux). Both DGGE and FISH results consistently showed that Rhodopseudomonas palustris, which may originate from spiked activated sludge, is more competitive to chemoheterotrophs than Rhodobacter sphaeroides precultivated as pure culture.
調査報告
  • 矢口 久美子, 鈴木 俊也, 五十嵐 剛, 安田 和男
    2004 年 27 巻 4 号 p. 267-272
    発行日: 2004/04/10
    公開日: 2008/01/22
    ジャーナル フリー
    An analytical method for methyl tertiary butyl ether (MTBE), which is added to gasoline as an oxygenate, by purge and trap gas chromatography - mass spectrometry was tested. The standard method for volatile organic chemicals (23 VOCs), which is used for determining the Japanese drinking-water criteria, was used for its analysis. The quantitative limit for MTBE by the selective ion monitoring mode was 0.01 μg·l-1, and the coefficient of variation at 0.01 μg·l-1 was 9.2 %. The recovery of spiked groundwater (0.01 μg·l-1) was 101±8.6 %. We found that it was possible to determine MTBE and the 23 VOCs simultaneously by this method. MTBE in groundwater was investigated in 246 wells at the Tama district in Tokyo. MTBE was detected from 26.5% of shallow wells and 19.7% of deep wells. The detected concentrations ranged from 0.01-47.7 μg·l-1, and the medians of the MTBE detected were 0.04 μg·l-1 (shallow wells) and 0.03 μg·l-1 (deep wells). We then periodically monitored samples from two wells where high levels of MTBE were detected. The MTBE concentrations of these groundwaters decreased to less than 1μg·l-1 after 6-12 months. This suggests that groundwater pollution by MTBE disappears rapidly.
  • 長南 学, 熊田 英峰, 村上 陽子, 藤原 祺多夫
    2004 年 27 巻 4 号 p. 273-279
    発行日: 2004/04/10
    公開日: 2008/01/22
    ジャーナル フリー
    The abiotic removal (i. e., flocculation and photolysis) of alkylphenols (i. e., nonylphenol (NP) and octylphenol (OP)) from the estuarine environment was studied by investigating the environmental distributions of these compounds in the Tamagawa river, Japan and the photoinduced decrease in their concentration in water and on the tidal flat. The concentrations of NP and OP in the dissolved from (<0.7μm) as well as in the ‘total’ (dissolved and particulate form) form decreased by 50% in the upper part of the inter tidal zone (salinity : 0-7‰). The ‘mixing experiment’ in which river water (salinity : 0‰) was mixed with seawater (salinity : 31.3‰) at various rates revealed an almost linear inverse relationship between total-NP and -OP concentrations and water salinity. These results suggest that alkylphenols are removed from the water column through a process other than flocculation. Irradiated for 8 hours using a solar simulator, the concentration of NP and OP dissolved in 1 mg·l-1 humic acid solution decreased significantly (-50%), whereas those in distilled water behaved more conservatively, this suggests that the photolytic decomposition of NP and OP can occur in natural waters. Although small, but significant amounts of alkylphenols were removed from a river sediment after a 6-hour exposure to sunlight, the anoxic production of NP and OP from their precursors in the sediment was revealed to be a far more important process than the photolytic decomposition.
  • 細谷 裕士, 横井 績, 富田 友幸, 矢永 純一, 梶原 義範
    2004 年 27 巻 4 号 p. 281-286
    発行日: 2004/04/10
    公開日: 2008/01/22
    ジャーナル フリー
    Seawater introduction to the reservoir of the Isahaya Bay Reclamation Project was carried out from April 24 to May 20, 2002. Seawater intake caused halocline and thermocline in the reservoir, and oxygen depression was temporarily observed in the vicinity of the drainage gates of the sea dike. Reductions in SS (suspended solids), COD (chemical oxygen demand), T-N (total nitrogen) and T-P (total phosphorus) in the reservoir, which were identified during the seawater intake, can be attributed to the dilution effect. In contrast, effluent loads into the coastal area outside the sea dike increased during seawater introduction periods due to the increase in drainage discharge from the reservoir.
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