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Volume 35 (1999)
- Issue 4 Pages 225-
- Issue 3 Pages 143-
- Issue 2 Pages 67-
- Issue 1 Pages 1-
Volume 35, Issue 1
Displaying 1-7 of 7 articles from this issue
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Kazuhiro Mori, Hiroyuki Igehara, Kazuya Yoshida, Atsuhiko Shinmyo, Mas ...1999 Volume 35 Issue 1 Pages 1-7
Published: March 15, 1999
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSPak-bung (Ipomoea aquatica) is a water plant which is useful to the water purification due to the high nutrient-removal capacity. An efficient plant regeneration method from septum segment of pak-bung were established. The septum calli were induced on the modified MS solid (MMS) medium supplemented with 1 mg/l of 1-naphthalene-acetic acid (NAA) and benzyladenine (BA) respectively. Shoots were regenerated from septum calli with various combinations of BA (0-10 mg/l) and NAA (0-1 mg/l) and the highest regeneration frequency (77%) were observed on the medium containing 5 mg/l of BA. Roots were induced successfully from all of the regenerated shoots applied to the rooting test and plantlets were reproduced. There was no morphological difference between regenerated plants and plants grew up from seeds. Using the culture conditions established in this study, the regenerated plant of pak-bung can be produced in a short period (4-6 weeks) .View full abstractDownload PDF (5684K) -
Yasuo Tanaka, Wendy T.M. Sanders, Grietje Zeeman1999 Volume 35 Issue 1 Pages 9-18
Published: March 15, 1999
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSBatchwise experiments were carried out to examine the effects of upflow velocity on mineralization and hydrolysis of waste activated sludge by a thermophilic acidifying UASB reactor. The waste activated sludge was filled in the reactor column (5 cm in diameter and 158 cm in height) and mineral nutrients solution was fed with different upflow velocity (0-0.5m/h) at 55°C for 4 days. Both the mineralization rate and the hydrolysis rate (sum of mineralization and solubilization rates) of the sludge changed significantly with the upflow velocity. A redox potential measured with Pt electrode and Ag/AgCl reference electrode increased markedly with the upflow velocity from about -300 mV to+150 mV. The redox potential seemed to be a useful index for regulating upflow velocity to maximize hydrolysis and mineralization rates of the sludge by the acidifying UASB reactor.View full abstractDownload PDF (876K) -
TERUHISA YOSHIDA, HIDEAKI HAMADA, MASANORI FUJITA1999 Volume 35 Issue 1 Pages 19-28
Published: March 15, 1999
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe OD (oxidation ditch) systems occasionally produce significant amounts of foam and scum.Then in this study, some OD plants were examined and the number of actinomycetes cells was assessed. The results obtained were as follows: Scumming was considered to be due to the growth of actinomycetes in the OD tank (aeration tank), which was largest in the OD process. In case of scumming, actinomycetes was found to be transferred from the MLSS to the scum and thickened. Then the multiple of thickening ranged from 1.5 to 5.8. The values of the specific growth rate calculated by the data of the three plants, were between 0.07 and 0.11 (1/day), which were about one half as large as that of the conventional activated sludge process. By comparison between the new scum and the old scum, actinomycetes was considered to increase not in the scum, but in the MLSS.View full abstractDownload PDF (940K) -
MASUO YAMAMOTO, SHIGERU OSHIMA, NOBUTADA NAKAMOTO1999 Volume 35 Issue 1 Pages 29-36
Published: March 15, 1999
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThis research was carried out to appreciate a slow sand filtration treatment by an investigation of suspended matter distribution in sand beds with covered of slow sand filter models (covered filter) . The core-sampler was inserted to take suspended matter in slow sand filter model beds during the filter operation when the filters were not easy to clog in summer. The following results were obtained.
Normahzed head loss value was increased at covered filter than at open filter after about 25 days of filter run. From the depth distribution of the Suspended Solid (SS) and Total Organic Carbon (TOC), covered filter detained larger amount of suspended matter than open filter. And suspended matter was detained at the extremely surface layer of the sand column with covered filter. The depth distribution of the Chlorophyll α indicated nearly opposite profile as SS, TOC distribution.View full abstractDownload PDF (871K) -
TSUTOMU IMAOKA, KAZUNARI MORI, MOTOHIRO BOKU, MITSUYA FUJIKAWA, MICHIH ...1999 Volume 35 Issue 1 Pages 37-47
Published: March 15, 1999
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe new system for the purification of polluted river water was proposed and examined.The system is composed of zeolite as the soil material in the tank and a silicon rubber tube laid in zeolite as the supplying system of a hydrogen donor (methanol) for denitrification. First, it was cleared that the methanol permeation velocity could be controlled by the membrane thickness and the methanol concentration in a tube (CMe) . Then, the effects of the hydraulic retention time (HRT=φ·V/Q, φ: porosity) and CMe to the removal of nitrogen were investigated using a small-sized experimental apparatus at room temperature of 20°C. The nitrogen removal from artificial polluted river water of NO3-N=10mg/l was about 70% under the condition of HRT=2hr and CMe=20%. Although the removal efficiency of nitrogen reached above 90% in the case of HRT=2hr and CMe=25-50%, the nitrogen removal rate per unit tank volume was saturated at about 1.7g/m3/hr. The on-site purification experiment of actual river water was performed using a large-scale experimental tank (1×1×4.8 m) in winter season in 1997. As the results, it was confirmed that the NH4-N, NO3-N and T-N removals on the condition of HRT=2hr and CMe=25% were 100%, 64% and 69%, respectively, in spite of low water temperature below 10°C.View full abstractDownload PDF (1222K) -
T.H. LEE, M. YOSHIMI, M. IKE, M. FUJITA1999 Volume 35 Issue 1 Pages 49-58
Published: March 15, 1999
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSAn enrichment culture taken from a contaminated site could efficiently degrade tetrachloroethylene (PCE) under a sequential anaerobic/aerobic condition. Under an anaerobic condition using citrate as a carbon source and yeast extract as a nutritional requirement, the enrichment culture could transfer 60 μM of PCE nearly stoichiometrically to cis-1, 2-dichloroethylene (cis-DCE) via trichloroethylene (TCE) within 3 days. A solution of 19.6% H2O2 was added atfinal concentration of 1.0% (v/v) to change the anaerobic condition of medium to aerobic one. Under the aerobic condition, more than 80% of cis-DCE accumulated was co-metabolized by indigenous phenol degrading bacteria in the enrichment culture. During the co-oxidation in the aerobic condition, all of phenol (125 mg/liter) added were completely consumed and population of phenol degrading bacteria was increased. The degradation of cis-DCE was affected by H2O2 (0.1-2.0% (v/v) ) and phenol (0-250 mg/liter) concentrations, indicating that the optimum doses of H2O2 and phenol are very important to lead successful co-metabolisms of less chlorinated ethylenes under aerobic conditions. The results from this research suggested that the sequential anaerobic/aerobic biostimulation would be viable as a cost-effective and safe bioremediation technique for degradation of PCE and less chlorinated metabolites. But it should need thorough investigation of microbial populations and their interactions for degrading chlorinated ethylenes under anaerobic and aerobic environments of contaminated sites.View full abstractDownload PDF (1165K) -
ISAO KIMATA, MOTOHIRO ISEKI, TAKASHI MURAKAMI1999 Volume 35 Issue 1 Pages 59-66
Published: March 15, 1999
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe ability of an electrolytic bacteriostatic system (model ABE-75, Konica Corp., Tokyo) to remove and inactivate Cryptosporidium parvum oocysts in water was evaluated.The system is equipped with an electrolyzer with eight bipolar electrodes made of porous carbon graphite, and water is treated by continuous circulation through the electrolyzer. When microorganisms such as Escherichia coli come in contact with the anodes of the electrodes, their reproductive activity decreases because of the electrochemical reaction between the electrode and the cells.The graphite used in these three-dimensional electrodes may adsorb microorganisms onto its large surface area.
In this experiment, 5 liters of water, containing 0.01% NaCl, spiked with 4×107 or 1.4×108 oocysts of C. parvum was treated with the electrolyzer. More than 99.99999% (7 log) of the oocysts were removed within 5 hours by filtration with the porous carbon graphite.The infectivity toward mice of oocysts obtained from the carbon graphite electrodes was reduced to 4% within this time.
Removal and inactivation of C. parvum oocysts in water by this electrolyzer were successful, showing that this bacteriostatic system purifies water efficiently.View full abstractDownload PDF (3040K)
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