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Volume 43 (2007)
- Issue 4 Pages 169-
- Issue 3 Pages 121-
- Issue 2 Pages 63-
- Issue 1 Pages 1-
Volume 43, Issue 4
Displaying 1-6 of 6 articles from this issue
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ORIGINALS
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ZHENYA ZHANG, ZHIYIN ZHANG, ZHONGFANG LEI, NORIO SUGIURAArticle type: ORIGINALS
2007 Volume 43 Issue 4 Pages 169-179
Published: 2007
Released on J-STAGE: March 10, 2018
JOURNAL FREE ACCESSSoil infiltration treatment (SIT) system commonly exhibited effective chemical oxygen demand (COD) removal, but few researches were focused on COD removal models. In shallow soil infiltration treatment (SSIT) systems, COD removal could be simulated by an integrated COD removal model with the effects of influent COD concentration (S0), water temperature (T) and nondegradable COD portion (Sn) on COD removal being incorporated into Eckenfelder Model. The results showed that the deviations could be within 5 mg l?1 for 95% of the data obtained from simulation and experiment when the integrated COD removal model being applied. This model can be used in the evaluation, analysis, prediction and management of COD removal in SSIT systems within the model application limits.View full abstractDownload PDF (787K) -
NOBUYUKI TANAKA, YUKO KUNIYASU, YUHEI INAMORI, TOMOAKI ITAYAMAArticle type: ORIGINALS
2007 Volume 43 Issue 4 Pages 181-188
Published: 2007
Released on J-STAGE: March 10, 2018
JOURNAL FREE ACCESSIn this study, ciliated protozoa Colpidium sp. and bacterium Enterobacter ludwigii isolated from a Johkaso were used to demonstrate the effect of protozoa for degradation of dissolved organic carbon in the biological wastewater treatment system. We examined changes of total organic carbon (TOC), dissolved organic carbon (DOC) and particulate organic carbon (POC) in concentration between the monoculture (E. ludwigii) and the mixed culture (E. ludwigii and Colpidium sp.) using modified Taub’s culture medium including peptone (200mg・l－1). In the monoculture system, 22.3mg－C・l－1 of DOC decreased for 2 days from the beginning of the culture. In this period, the average cell density of E. ludwigii was 3.9×108 CFU・ml－1. On the other hand, in the mixed culture system, 32.7mg－C・l－1 of DOC decreased in 2 days from the beginning of the culture. In this period, the average density of E. ludwigii was 2.9×108 CFU・ml－1. Consequently, the larger amount of DOC decreased in the mixed culture system than the monoculture system, though the cell density of bacteria in the mixed culture system is lower than that in monoculture system. Moreover, it was estimated that the rate in decrease of DOC per POC in the mixed culture system was 130 times of the rate in the monoculture system. From these results, it was strongly suggested that protozoa enhanced the activity of DOC degradation in the microbial ecosystem in the biological wastewater treatment system.View full abstractDownload PDF (978K) -
MAHMUDUL KABIR, MASAFUMI SUZUKI, NOBORU YOSHIMURAArticle type: ORIGINALS
2007 Volume 43 Issue 4 Pages 189-197
Published: 2007
Released on J-STAGE: March 10, 2018
JOURNAL FREE ACCESSIn this paper, we have reported the effect of magneto-ferrite treatment on the reduction of excess activated sludge in the laboratory scale. This magneto-ferrite treatment is a new approach for reduction of excess sludge by using ferrite particles and permanent magnets. First, we determined the parameters for this method and then with the parameters, we observed the effect of this new method on activated sludge with the running method of Conventional Activated Sludge (CAS) of a Waste Water Treatment Plant (WWTP). Two miniature WWTPs were used at the laboratory, which one was run with magneto-ferrite treatment while another was run without any treatment. The observations showed good results in reduction of excess sludge growth. The growth of excess sludge was controlled at 42% comparing to that of non-treatment system running WWTPs with CAS. The results showed good possibilities of reducing sludge in the arena of biological waste water treatment.View full abstractDownload PDF (6792K) -
HIROKO TSUKATANI, YUSUKE KAJIHARA, YOSHITERU BABAArticle type: ORIGINALS
2007 Volume 43 Issue 4 Pages 199-207
Published: 2007
Released on J-STAGE: March 10, 2018
JOURNAL FREE ACCESSBiodegradation rate of polycyclic aromatic hydrocarbons (PAHs) was evaluated using river sediments sampled in Fukuoka Prefecture to assess their fate in the sediment environment. Three sediments (Nos. 1－3) with distinct properties were selected among 18 sediments, and Nos. 1, 2 and 3 were characterized as the samples with PAHs contamination at low, medium and high concentrations, respectively. Fifteen PAHs were spiked to the sediment samples, and they were kept at 20 ℃ in dark during 4 weeks for the biodegradation tests. Significant degradation of naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo(a)anthracene, and chrysene was observed in No.1 sediment, while Nos. 2 and 3 could degrade only naphthalene, acenaphthene, fluorene, and phenanthrene. The PAHs degradation proceeded most efficiently in No. 1 sediment with the half-lives of the above 9 PAHs of 3－36 days. Although No. 3 sediment was sampled the downstream of the area heavily polluted with PAHs, especially with extremely high level of naphthalene (19,000 μg/g－dry), it was less effective for the PAH degradation than No.1 sediment unexpectedly. The oxidation-reduction potential was measured before and after the degradation tests, and the results showed that No. 1 sediment was kept the most oxidative during the experimental period, suggesting efficient degradation of PAHs in the sediments can occur under oxidative conditions.View full abstractDownload PDF (1759K) -
MINZHE AN, YUEQIN TANG, SHIGERU MORIMURA, KENJI KIDAArticle type: ORIGINALS
2007 Volume 43 Issue 4 Pages 209-217
Published: 2007
Released on J-STAGE: March 10, 2018
JOURNAL FREE ACCESSDistillation wastewater from a continuous ethanol fermentation process using the acid hydrolysate of wood biomass was fed into a methane fermentation reactor and treated anaerobically. The maximum TOC volumetric loading rate was only 1.0 g/l/d without aeration, but improved to 3.0 g/l/d with micro-aeration to suppress H2S buildup. By supplying air equivalent to 9.0 vol% of the evolved biogas into the top of the fixed-bed reactor, H2S concentration decreased to less than 50 ppmv (ml/m3) and the efficiency of SO42– removal was more than 99.5%. The methane concentration in the biogas was maintained around 45% when micro-aeration was used. The effluent from the simultaneous methane fermentation and sulfur removal process was then subjected to biological denitrification-nitrification treatment by recirculating the effluent from the nitrification reactor. As a result, NH4+－N was reduced to less than 5.0 mg/l without the addition of electron donors such as methanol.View full abstractDownload PDF (830K) -
MASAHIRO KAWABATA, TOMONORI FUJII, TAKASHI KAMEYA, TAKESHI KOBAYASHIArticle type: ORIGINALS
2007 Volume 43 Issue 4 Pages 219-226
Published: 2007
Released on J-STAGE: March 10, 2018
JOURNAL FREE ACCESSA method based on the image analysis of the activity of Medaka (Oryzias latipes) was investigated for continuous water quality monitoring. The image dots of 5,760 were set in the monitor tank (39cmW×45cmL). The number of dots in which the image was changed in one second was continuously counted, and then standardized using their daily average value in order to evaluate the relative activity. The control of the circulation water speed in the monitor tank was important for the image analysis of the activity of moderately stable Medaka swimming. The change in temperature to lower than 15 ℃ or higher than 40 ℃ produced a severe drop in Medaka’s activity even without chemical contamination. The useful alarm for a water quality problem could become available by the classification of the relative activity within a few hours depending on the concentration of the chemicals.View full abstractDownload PDF (1052K)
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