Japanese Journal of Water Treatment Biology
Online ISSN : 1881-0438
Print ISSN : 0910-6758
ISSN-L : 0910-6758
Volume 46, Issue 2
Displaying 1-5 of 5 articles from this issue
ORIGINALS
  • YOSHINOBU YAMAGIWA, WATARU TAKATSUJI, MOTONOBU NAKAOKA, KENJI FURUKAWA
    Article type: ORIGINALS
    2010 Volume 46 Issue 2 Pages 71-79
    Published: 2010
    Released on J-STAGE: March 10, 2018
    JOURNAL FREE ACCESS
    Wastewater from the dye industry contains high level of organic nitrogen derived from urea. Thus, an effective nitrogen removal process is needed to reduce effluent nitrogen concentration. We have developed a new nitrogen removal process using non-woven biomass carriers. In this study, we used pile fabrics, which are products of the local industry in the Wakayama prefecture, instead of non-woven materials as biomass carriers to improve nitrification rates. Several pile fabrics were then used for nitrification and continuous nitrification/denitrification experiments. The specific NOx-N production rate using an acrylic pile fabric was 3.4 times higher than that of non-woven carriers. About 75% nitrification efficiencies were obtained under a T-N loading rate of 0.5 kg-N/m3/day and a HRT of 10 hours during continuous nitrification using acrylic pile fabrics. Furthermore, continuous nitrification/denitrification experiments were carried out using acrylic pile fabrics in a base cloth with a mesh structure to improve the diffusion rates. Little biomass accumulated on the pile fabric surfaces so a high diffusion rate through the pile was maintained for long periods. Denitrification efficiencies of 56 and 77 % were achieved at HRTs of 12 and 19 hours, respectively, with influent concentrations of 200 mg/l T-N and 450 mg/l TOC.
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  • HLWAN MOE ZAW, SATOSHI FUKUSHIMA, HIROMI KOBORI
    Article type: ORIGINALS
    2010 Volume 46 Issue 2 Pages 81-90
    Published: 2010
    Released on J-STAGE: March 10, 2018
    JOURNAL FREE ACCESS
    This study was carried out to clarify the effects of residual chlorine in two rivers on epilithic algal communities. The two rivers of this study are the Onda River and the Itachi River in Yokohama City, receiving the chlorinated sewage effluent. The epilithic algal and water quality were investigated at three sites in both rivers. The number of species of epilithic algal communities was 7 in winter and 5 in summer at the site of high TRC concentration (0.5mg/l) by the sewage effluent, and those was fewer than the number, more than 20, obtained at the site of low TRC concentration (lower than 0.1mg/l). In addition, Chlamydomonas sp. and Monoraphidium fontinale, green algae and tolerant species for chlorine, predominated at the site of high TRC concentration. However, at the site where has the low TRC concentration than 0.1mg/l down from the site of high TRC concentration, diatoms appeared predominantly and the number of species was more than 20 therefore it is confirmed that epilithic algal communities could be recovered.In order to estimate the effects of chlorine on algal growth, artificial clay tiles were placed at each study site. The number of species of epilithic algal communities on artificial clay tiles at the site of high TRC concentration was fewer than 6 species on an average all through the two months investigation period. In addition, by removing artificial clay tiles to the site of high TRC concentration from the site of low TRC concentration, the number of species of algae was decreased, and the structure of communities was replaced the predominant species at the site of high TRC concentration. These results indicated that TRC effects on epilithic algal communities in the river.
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  • WATARU TAKATSUJI, YOSHINOBU YAMAGIWA, KENJI FURUKAWA
    Article type: ORIGINALS
    2010 Volume 46 Issue 2 Pages 91-97
    Published: 2010
    Released on J-STAGE: March 10, 2018
    JOURNAL FREE ACCESS
    BF–T9P, a nonwoven fiber material, can be used as an effective biomass carrier for yeast (UY7 strain) in the treatment of wastewater generated during the production of seasoned salty plums. However, the cost is a major problem in small and medium scale companies. We investigated the feasibility of using a pile fabric biomass carrier that can be produced at low cost with existing equipment. The TOC removal rate of E–pile, a polyester pile fabric, was as high as that of the nonwoven material under a volumetric loading rate of 4 to 15 kg–TOC/m3/d. A packing ratio of 0.17 m3–carrier/m3–reactor was sufficient for TOC removal if the volumetric loading rate was less than 8 kg–TOC/m3/d. In a system using a biomass carrier, the decrease in TOC removal caused by a temperature drop from 25 to 5℃ was slower and the increase in TOC removal upon raising the temperature to 10℃ was faster, compared with a system without a biomass carrier. These results may be attributed to the stable retention of yeast in the reactor by entrapment inside the biomass carrier.
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  • HIROSHI YAMAZAKI, RIE SUZUKI, YOSHITAKA EBIE, KAI QIN XU, YUHEI INAMOR ...
    Article type: ORIGINALS
    2010 Volume 46 Issue 2 Pages 99-107
    Published: 2010
    Released on J-STAGE: March 10, 2018
    JOURNAL FREE ACCESS
    Effect of anaerobic-aerobic circulation ratio and HRT on BOD and nitrogen removal efficiencies in simultaneous treatment of domestic wastewater and kitchen garbage disposer wastewater was investigated by using small scale Johkasou model reactors. The optimum circulation ratio and HRT were determined as 6 and 59.7 hrs to achieve target effluent water quality, BOD 10 mg l-1 and T-N 10 mg l-1. According to the results of this experiment, reactor volume of simultaneous treatment of domestic wastewater and disposer wastewater should be 1.21 times bigger than advanced domestic wastewater treatment Johkasou to attain the same performance. life cycle CO2 evaluation was conducted to compare the impacts of the following two scenarios. The first one is a present case in which kitchen garbage is incinerated with other domestic waste and domestic wastewater is treated in advanced Johkasou, and the second case is a simultaneous treatment of domestic wastewater and kitchen garbage in advanced Johkasou. In the second case, volume of the Johkasou was determined according to the results of above experiment. Potential contributions to CO2 emission in the processes of domestic waste treatment and domestic wastewater treatment were assessed by LCCO2 in these two cases, individually. Although CO2 emission in wastewater treatment process increased in a case of a simultaneous treatment of kitchen garbage and domestic wastewater, transportation amount of domestic waste was decreased and net CO2 emission was reduced by 4.2% (-25.6 kg-CO2 house-1 year-1).
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  • LAI MINH QUAN, TRAN THANH LIEM, DO PHUONG KHANH, KENJI FURUKAWA
    Article type: ORIGINALS
    2010 Volume 46 Issue 2 Pages 109-117
    Published: 2010
    Released on J-STAGE: March 10, 2018
    JOURNAL FREE ACCESS
    Appropriate biomass retention in the reactor is crucial to the operation of the anaerobic ammonium oxidation (anammox) process due to the extremely slow growth rate of the bacterial population. In the present work, anammox sludge, immobilized in a poly vinyl alcohol (PVA)/sodium alginate gel, was studied to improve anammox biomass retention in the reactor. 150 ml of concentrated anammox sludge (33.3 g suspended solids l–1) was entrapped into a PVA/alginate aqueous solution (15% w/v PVA and 2% w/v alginate) at a volumetric ratio of 1:1 that was then solidified in a solution containing 50% w/v NaNO3 and 2% w/v CaCl2. The anammox activity increased gradually and reached a maximum nitrogen loading rate of 9.9 kg–N m–3 d–1, with a removal efficiency of more than 80% even at a low hydraulic retention time of 2.67 h, after 250 days of operation when the bicarbonate concentration was increased to 1.0 g l–1 as KHCO3 from day 145. A porous structure in the PVA/alginate immobilized biomass beads was observed by scanning electron microscopic (SEM) analysis. This study shows the potential for the treatment of wastewaters containing high ammonium and low carbon, such as digester liquor, using PVA/alginate gels for whole cell entrapment of anammox sludge.
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