Chūō-ku, Japan
Chūō-ku, Japan

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Suzuki S.,Nippon Steel Kankyo Engineering Co. | Abe K.,Nagaoka University of Technology | Ohashi A.,Hiroshima University | Harada H.,Tohoku University | And 3 more authors.
International Journal of Environmental Research | Year: 2011

An airlift-type activated sludge reactor using a sponge support medium was fed with wastewater containing 500 mg-N/L of NH 4 +-N. In order to establish partial nitrification, the reactor was kept at 35°C. Moreover, the reactor was started up with the NaHCO 3 solution as an alkali agent to supply inorganic carbon for enhancement of partial nitrification. The partial nitrification was established during the period when NaHCO 3 was used as an alkali agent. However, soon after changing the alkali agent to a mixture of Na 2HPO 4 and NaOH, the production of NO 2 --N started to decrease. The change in pH inside the sponge medium revealed by the model simulation and microelectrode study showed relatively high free ammonium concentration inside the medium. Thus, partial nitrification was proved to be affected by inorganic carbon in the alkali agent. Furthermore, it was suggested that the establishment of partial nitrification in this study was due to the combination of high operating temperatures, addition of inorganic carbon, and the inhibition of NOB by the free ammonium concentration.

Sekikawa T.,University of Shizuoka | Kawasaki Y.,Ebara Jitsugyo Co. | Katayama Y.,Ebara Jitsugyo Co. | Iwahori K.,University of Shizuoka
New Biotechnology | Year: 2011

Detection of low amounts of Cryptosporidium oocysts in raw water sources is considered an important component in the management, prevention and control of Cryptosporidium in drinking water supplies as Cryptosporidium causes massive waterborne outbreaks worldwide. As Cryptosporidium has a robust oocyst that is extremely resistant to chlorine and other drinking water disinfectants, both the freeze-thaw method and DNA extraction kits have been commonly used for extracting and purifying DNA from the oocyst. However, the DNA extraction procedures are time consuming and costly. Therefore, a simple and low-cost method to extract and purify DNA from the robust oocyst has been required. In this study, we discussed a simple method for detecting Cryptosporidium DNA with the anionic surfactant, n-lauroylsarcosine sodium salt (LSS) using the loop-mediated isothermal amplification (LAMP) to eliminate the need for the freeze-thaw method and the DNA extraction kits. As a result, Bst DNA polymerase was inhibited by 0.1% LSS but not 0.01% LSS and 5% Triton X-100 or Tween 20. Although DNA was extracted from the oocysts by incubating with 0.1% LSS at 90°C for 15. min, Bst DNA polymerase was inhibited by 0.1% LSS. The inhibition by 0.1% LSS was suppressed by adding 5% of the nonionic surfactants, Triton X-100 or Tween 20. The concentration of LSS in a LAMP tube was 0.01% while that in an incubation tube was 0.1%, because LSS in an incubation tube was diluted by a factor of 10 at the DNA amplification process. Therefore, we found that ten oocysts of Cryptosporidium parvum could be detected by incubation with 0.1% LSS, without removing LSS or adding the nonionic surfactants in the LAMP method. © 2011 Elsevier B.V.

Arakawa K.,EBARA JITSUGYO CO. | Suyama T.,Ebara Corporation | Tanaka T.,EBARA JITSUGYO CO.
Ozone: Science and Engineering | Year: 2011

Since excess sludge is generated by the process of the biological treatment of waste water, the effect of ozonation on sludge reduction by ozonation is being noted. The mechanism of sludge reduction by ozonation is the process of applying the liquefaction of microbial cells by ozonation as described here. Sludge reduction by ozonation liquefies microbial cells in the sludge and consequently the organic matter, phosphorus and nitrogen, which consist of the cells dissolved into the liquid. When the dissolved matters are run through the biological treatment process, the organic matter and nitrogen are removed again by the activated sludge through the addition of oxygen. We took note of the fact that the major part of the exhaust gas from the ozone reactor is oxygen, and made the best use of this exhaust gas as an oxygen supply resource to develop a biological treatment process (Anaerobic-Anoxic-Oxic) by excess sludge reduction. We set up this plant and made evaluations of the process capability at the site of EXPO 2005 Aichi, Japan. In this paper we demonstrate the construction of the plant and the results of the operation. The main results are: (1) The gas issued from the ozone reactor contained sufficient oxygen for the reaction in the oxic tank; and, (2) The sludge generation of the ozonation process was reduced to 24% of the conventional process. The removal of COD and T-N also worked well. © 2011 International Ozone Association.

Matsuo K.,Kyushu Institute of Technology | Takatsuji Y.,Kyushu Institute of Technology | Takatsuji Y.,Japan Science and Technology Agency | Kohno M.,Tokyo Institute of Technology | And 5 more authors.
Electrochemistry | Year: 2015

Efficient generation of oxygen radicals and reactive oxygen was successfully performed at the dispersed-phasic interface between vapor-water and oxygen plasma in a reaction chamber having an internal atmosphere with a normal-pressure and temperature. In the space of the reactor chamber (radical vapor reactor [RVR]), the gas phase was strictly controlled in terms of vaporized water (small water mist), temperature, plasma conditions, and UV irradiation. According to spin-trapping electron spin resonance analysis, the RVR efficiently and quantitatively yielded two types of reactive oxygen species (1O2 and OH radical) with the atmosphere of the RVR chamber. This is the report of the efficient, quantitative production of reactive oxygen in an atmosphere. The reactivity of the produced 1O2 and OH radical may be applicable for various chemical processes, such as oxidation and electron absorption. © 2015 The Electrochemical Society of Japan, All rights reserved.

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