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Volume 40 (2004)
- Issue 4 Pages 125-
- Issue 3 Pages 77-
- Issue 2 Pages 37-
- Issue 1 Pages 1-
Volume 40, Issue 4
Displaying 1-5 of 5 articles from this issue
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HIDEKI TATSUMOTO, YUICHI ISHII, MOTOI MACHIDA, MASAMI AIKAWA, YOKO FUJ ...2004 Volume 40 Issue 4 Pages 125-135
Published: December 15, 2004
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSMacroalgae, Ulva sp., seawater and sediments in Yatsu tidal flat, Japan were examined to clarify the characteristic distributions of heavy metals and their interactions within these compartments of the ecosystem. The heavy metal concentrations were higher in fall than summer for Fe, Cu and Zn, but were constant with respect to season for Pb and Cd. The distribution of heavy metals in Ulva sp. harvested from Yatsu tidal flat was close to in Ulva sp. grown in other parts of the world with the following decreasing order of concentration of Fe>>Zn>Cu≥Pb>>Cd, but differed from that of other. Ulva spp. was considered to have an inherent characteristic ratio of heavy metals. In the sediments, heavy metal content was higher in the muddy area of the tidal flat than sandy area, while the compositions were similar for the two areas. The difference in heavy metal content would be attributed to the difference in organic matter and sediment particle size. The major heavy metal in the suspended particulate matter (SPM) in seawater was determined to be Fe followed by Zn, Pb, Cu and Cd, which exhibited a similar composition as those in the sediments. SPM was considered to be derived by tidal shear forces. Absorption of heavy metals into Ulva sp. did not depend on the seawater concentrations, but on the absorbability inherent in Ulva sp. In comparisons of Concentration Factors for heavy metals in Ulva sp., essential elements as Fe, Cu and Zn were preferentially absorbed compared to nonessential metals as Pb or Cd.View full abstractDownload PDF (1458K) -
TATSUHIKO HOSHINO, HIDENOBU HIROSAWA, TADAFUMI MATSUKAWA, TOMOYUKI OGA ...2004 Volume 40 Issue 4 Pages 137-142
Published: December 15, 2004
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSWastewater containing high nitrogen and high salinity is discharged from the processes of recovering precious metals from industrial waste. Because high salinity inhibits metabolic activity of microorganisms, biological nitrogen removal from such a wastewater has a lot of difficulties. The purpose of this study is to develop an effective nitrification denitrification process for industrial saline-wastewater. At first, nitrogen removal from this wastewater was attempted using a normal suspended nitrifying sludge system. In consequence of estimating tolerance of such a sludge system to salinity, nitrification progressed up to 5% of salt concentration. However, keeping MLSS at 5, 000 g/m3 is necessary to achieve practical nitrification rate. Therefore, nitrifying granules resulting from an aerobic upflow fluidized bed reactor for inorganic wastewater containing high concentration of NH4-N were applied to this industrial saline-wastewater. In consequence of operating nitrification reactor at various salt concentrations, MLSS was kept at 12000g/m3 throughout the operation, and sufficient nitrogen removal rate was achieved. Finally, the nitrifying granules were applied to an aerobic reactor in the aerobic-anaerobic nitrogen removal system. As a result, nitrogen in the saline wastewater was completely removed for 150 days. Through these experiments, it is demonstrated that nitrifying granules are effectively applied to nitrogen removal from industrial saline-wastewater.View full abstractDownload PDF (666K) -
HIROSHI OGAWA, AYAKO HOJO, NAOYUKI MIYATA, KEISUKE IWAHORI2004 Volume 40 Issue 4 Pages 143-151
Published: December 15, 2004
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe inflow and discharge of estrogens and endocrine disrupting chemicals (EDCs) in actual condition were examined for the domestic wastewater treatment facilities over one year. The contents of EDCs in effluents were as fbllows : 17β-estradiol (E2), N.D. (not detected) -0.0078μg/l; bisphenol A (BPA), 0.10-1.55μg/l; nonylphenol (NP), 3.52-34.6μg/l; di- (2-ethylhexyl) phthalate (DEHP), N.D.-0.15, μg/l; di-n-butyl phthalate (DBP), N.D. The removals of the EDCs were more than 80%. When the mass balance of EDCs were calculated, it became clear that 50% and more of the amounts of inflow EDCs were being adsorbed by sludges in anaerobic filter tank, and effect on the decrease in the EDCs by anaerobic filter tank was suggested.View full abstractDownload PDF (1150K) -
YUKI IKEDA, YOSHIHIKO KURAHASHI, KOHJI NAKAMURA, TADAAKI MORI, TOSHINO ...2004 Volume 40 Issue 4 Pages 153-160
Published: December 15, 2004
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe heat pretreatment conditions of food refuse such as leftover food collected from restaurants were examined to improve the gas production efficiency in the mesophilic methane fermentation. In the bench-scale continuous experiment of the mesophilic methane fermentation at the VS loading rate of 2.5kg-VS/m3/day and the HRT of 29 days, the VS removal was improved and the gas production per influent VS increased by 19% with the heat pretreatment. The methane content of produced gas was 68% and there was no difference from that obtained from the control test using non-heat-treated waste.The methane yield per removed VS and the efficiency of carbon conversion to methane were also improved significantly with the heat pretreatment. The measured gas production yield and methane content with the heat pretreatment were notably greater than the theoretically calculated value estimated by the approximate molecular formula and the stoichiometric equation reported to agree well with the experimental results in thermophilic methane fermentation on organic matters in municipal solid waste. The trial calculation results of the energy balance showed that the amount of power generation and available thermal energy can be increased even after compensating the heat required for the pretreatment of waste.View full abstractDownload PDF (1044K) -
SHIGEKI YAMAMURA, SACHIKO TERASHI, MICHIHIKO IKE, MITSUO YAMASHITA, MA ...2004 Volume 40 Issue 4 Pages 161-168
Published: December 15, 2004
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSA gram-positive and facultative anaerobic bacterium, Bacillus sp. SF-1, which was isolated from selenium-polluted sediment, can grow on lactate as an electron donor and selenate, arsenate or nitrate as an alternate electron acceptor in the absence of oxygen. This strain seems to be a promising agent for bioremediation of selenium/arsenic. In an effort to characterize the reductase systems in strain SF-1, arsenate, selenate and nitrate reduction activities were investigated with washed-cell suspensions and crude cell extracts from cells grown on arsenate, selenate and nitrate. These reductase activities were induced individually by the respective electron acceptors. Tungstate, which is a typical inhibitory antagonist of molybdenum-containing dissimilatory reductases, strongly inhibited reduction of arsenate, selenate and nitrate in the anaerobic growth cultures. These results suggested that strain SF-1 catalyzes the reduction of arsenate, selenate and nitrate by distinct terminal reductases containing molybdenum as a cofactor. This may be an advantage to utilize SF-1 in the bioremediation precesses where contaminants exist in mixture.View full abstractDownload PDF (1112K)
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