成果報告書詳細
管理番号20100000001989
タイトル*平成21年度中間年報 「微生物群のデザイン化による高効率型環境バイオ処理技術開発/内生呼吸低減菌等の有用微生物群による高効率好気水処理技術の研究開発」
公開日2010/11/10
報告書年度2009 - 2009
委託先名株式会社日立プラントテクノロジー
プロジェクト番号P07024
部署名バイオテクノロジー・医療技術開発部
和文要約和文要約等以下本編抜粋:1. 研究開発の内容及び成果等 本研究開発では,活性汚泥を構成する微生物フローラに着目した。曝気による酸素供給のかなりの部分は環境汚染物質の分解に使われておらず,生命維持のための内性呼吸に使用されている。そこでフローラ菌種を人為的に限定し,内生呼吸低減菌などの菌群選定により内性呼吸量の低減を図り,曝気量に対する処理効率を向上させることを目的とする。 平成19年度-21年度では,内生呼吸低減菌の探索及びフローラの機能を安定化させるための包括固定化用高分子ゲルを設計する。この高分子ゲルを用いてフローラを包括固定化し,機能を向上させた固定化微生物担体を得る。
英文要約Annual report 2009: High efficiency wastewater treatment using “novel microorganisms” with low endogenous respiration
Hitachi Plant Technologies, Ltd. & Chuo University
The energy and cost expenses for aeration in an activated sludge plant are intensive and tremendous, of which fraction often exceeds a half of total cost expenses of the plant. As it has been long desired to reduce this heavy burden of expenses for aeration, we are pursuing to develop a cost- and energy-saving wastewater treatment system mainly by adopting a reliable technology of gel-immobilized activated sludge combined with an innovative technology for pre-fixing one or combination of several target microbes into the gel.
In fiscal year 2009, we isolated several strains with reduced endogenous respiration from activated sludge and gel carriers. In addition, alkaline-shock method was evaluated for the disinfection of contaminated microorganisms on gel carriers immobilized isolates. And finally, we constructed a wastewater treatment system for the test of partial nitritation treatment using the alkaline-shock method.
(1) Evaluation of endogenous respiration for selecting strains with high oxygen utilization efficiency.
Bacterial strains were isolated from activated sludge samples and gel-immobilized sludges. Oxygen consumption rates of isolates were determined with and without external addition of substrate; the former was regarded as exogenous respiration rates and the latter endogenous respiration rates. Oxygen utilization coefficient, R, was calculated as ratio of endogenous respiration rate and exogenous respiration rate of each strain. Among 33 strains examined, 6 strains had a high oxygen utilization efficiency, of which R was over 10.
If they are applied to wastewater treatment via such techniques as gel-immobilization, most of oxygen consumed would be utilized mainly toward oxidizing supplied BOD, as their endogenous respiration rates are quite small. Therefore, it can be expected that cost expenses for electricity for aeration should be saved by applying these strains
(2) Examining substrate utilization pattern for selecting strains with broader substrate utilization range.
Since a treatment plant receives wastewater carrying various types of substances, the strain would be required to be capable of utilizing a wider variety of substances, if one or combination of several of such strains as those with a high R value mentioned in the previous paragraph. Strains with a high R value were further characterized for the range of substrate utilization, and some which possessed a broader utilization range of substrates were found.
(3) Improvement of the operational stability of the immobilized isolates.
Gel carriers immobilized pure culture microorganisms are readily contaminated in sewage by other microorganisms. For this reason, an alkaline- shock method was evaluated for the disinfection of contaminated microorganisms on carries containing Stenotrophomonas rhizophila strain E1, Arthrobacter sp. strain B4 and Achromobacter sp. strain E7 , respectively. As a result, the isolates were not killed by the shock and kept up the growth activity. Therefore, it can be expected that low endogenous respiration should be kept in actual wastewater treatment.
(4) Design and construction of a pilot-scale wastewater treatment plant
We designed and constructed a wastewater treatment plant for the test of partial nitritation treatment using the alkaline-shock method.
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