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Predecessor
Volume 30, Issue 1
Displaying 1-5 of 5 articles from this issue
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Notes
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Toshiya UCHIBORI, Kenji FUJITA, Takeshi FUJINO, Takashi ASAEDAArticle type: Note
2007 Volume 30 Issue 1 Pages 23-26
Published: 2007
Released on J-STAGE: January 09, 2010
JOURNAL FREE ACCESSA kaolin suspension with a turbidity of about 200 NTU was used to simulate raw retentate and electrolyzed using a newly designed cell consisting of a platinized titanium anode and a steel cathode covered with filter paper. After the electrolyzed suspension, which had a pH less than 4, was adjusted to pHs 5.5-7.0, the adjusted suspension was studied in terms of how its aggregation behavior related to mixing strength (40, 90 and 160 rpm), focusing on residual turbidity, sludge concentration and colloid charge shift. The electrolysis treatment decreased the residual turbidity after an about 50-h retention to one-third of that of the untreated suspension and did not affect the sludge concentration. The aggregation of the treated suspension was considered from the viewpoint of the colloid charge shift along with the increased aluminum ion concentration in the treated suspension.View full abstractDownload PDF (478K) -
Yaozong JIANG, Tomoatsu YANAGITA, Tomotaka YANAGITA, Tomoyo MITANIArticle type: Note
2007 Volume 30 Issue 1 Pages 27-31
Published: 2007
Released on J-STAGE: January 09, 2010
JOURNAL FREE ACCESSVolcanic ash soil heated with ferrous sulfate (VASHF) has a large specific surface area and is porous. VASHF particles have a rough surface and contain micropores with a diameter in the range of 0.003-100 μm. Pores having a diameter larger than 5 μm account for 41.6% of micropores. Moreover, VASHF also has a positive charge. The ability of VASHF to remove algae was examined in terms of the particle size of VASHF, line velocity and the thickness of VASHF. It was shown that VASHF can remove algae from water. The algal removal mechanism of VASHF is considered to be a result of the retention of algae due to the number of pores among particles, the irregularity of the surface and the micropores diameter of the particles, and also of the adsorption of algae due to the particles having a positive charge. Moreover, H2SO4 treatment is the most effective method of recycling used VASHF that contains adsorbed algae. This allows VASHF to be reused.View full abstractDownload PDF (821K)
Technical Reports
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Kenji OKINAKA, Tomoko OKITA, Koji KAKUYA, Masayuki UEGAMIArticle type: Technical Report
2007 Volume 30 Issue 1 Pages 33-37
Published: 2007
Released on J-STAGE: January 09, 2010
JOURNAL FREE ACCESSFrom the catalystic dechlorination rates of trichloroethylene with four types of iron particle determined by the static method, it was confirmed that the reaction rates of these particles can be expressed as a pseudo-first-order reaction and that α-Fe · Fe3O4 composite nanoparticles showed the highest reaction rate. As determined by static method, the “specific” reaction rate constants of iron nano- and microparticles tended to remain at certain values. Whereas they tended to decrease when the load of the particles increased. The reaction rate and “specific” reaction rate constants of iron nano- and microparticles decreased when the initial TCE concentration was high increased. The reaction rate constants of iron nanoparticles decreased markedly at a low pH and they increased at a high pH. However, the reaction rate constants of iron microparticles hardly depended on pH.View full abstractDownload PDF (447K) -
Asa MIURA, Eisaku SHIRATANI, Tadayoshi HITOMI, Ikuo YOSHINAGA, Kyoji T ...Article type: Technical Report
2007 Volume 30 Issue 1 Pages 39-44
Published: 2007
Released on J-STAGE: January 09, 2010
JOURNAL FREE ACCESSThe purpose of this study is to examine dissolved organic matter (DOM) removal using charcoal made from Japanese cedar wood (Cryptomeria japonica D. Don). We used three types of charcoals carbonized at 450, 650, and 1050°C to compare their DOM removal rate and removal volume. The removal rates of DOM contained in rice-straw water and the DOM-fraction distribution in treated water were studied in laboratory experiments. The results showed that the charcoal at 1050°C (C1050) markedly removed DOM from rice-straw water. C1050 removed of 70% DOM in 48 h. UV (260 nm) absorbance, which can be used for the index of recalcitrant DOM concentration, decreased to 30% with C1050 treatment. DOM fractionation in treated water in 48 h showed that C1050 removed 97% of the hydrophobic acid contained in recalcitrant DOM. The molecular weight distribution showed that C1050 removed high-molecular-weight compounds including humic substances.View full abstractDownload PDF (991K)
Survey Report
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Takayuki NAKAJIMA, Yoshimi FUJIWARA, Meiko WAKABAYASHI, Kunihiko YAMAZ ...Article type: Survey Report
2007 Volume 30 Issue 1 Pages 45-47
Published: 2007
Released on J-STAGE: January 09, 2010
JOURNAL FREE ACCESSThe concentrations of five metals (Zn, Cd, Cu, Ni, and Pb) in Tokyo Bay water were determined using inductively coupled plasma atomic emission spectrometry (ICP-AES). Eighteen stations were selected for the survey from the environmental standard points, and water samples in the surface, middle and bottom layers were collected from each station for metal concentration determination. The metal concentrations (μg · l-1) ranged from <2 to 73 for Zn, <0.1 to 1.8 for Cd, <2 to 20 for Cu, <20 to 44 for Ni, and <2 to 3.9 for Pb. Similarly to the PRTR data, Zn concentration was higher along the Tokyo and Kanagawa areas than along the Chiba area. Two water samples had a Zn concentration exceeding the water quality standard concentration for “aquatic life class A”. Thirteen water samples had a Zn concentration exceeding the water quality standard concentration for “aquatic life class special A”.View full abstractDownload PDF (350K)
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