JP3607353B2 - Organic aminocarboxylic acid degrading bacteria and method for treating waste liquid using the same - Google Patents

Description

【００３７】
【表２】

【００３８】
【表３】

【００３９】
本発明によれば、各種有機アミノカルボン酸類を分解することができる。分解の対照となる有機アミノカルボン酸類としては、有機アミノカルボン酸の遊離酸若しくはその塩（例えば、ナトリウム、カリウム等のアルカリ金属やアンモニウム、アルカノールアミンとの塩）やその金属錯体、例えば、鉄、銅、カルシウム、マグネシウム、コバルト、マンガン、金などとの金属錯体が挙げられる。
有機アミノカルボン酸（遊離酸）若しくはその塩としては次のものが、代表例としてあげられる。
Ｂ−１ エチレンジアミン四酢酸（ＥＤＴＡ）
Ｂ−２ ジエチレントリアミン五酢酸
Ｂ−３ １，２−ジアミノプロパン四酢酸
Ｂ−４ １，３−ジアミノプロパン四酢酸（ＰＤＴＡ）
Ｂ−５ ブチレンジアミン四酢酸（ＢＤＴＡ）
Ｂ−６ エチルエーテルジアミン四酢酸
Ｂ−７ グリコールエーテルジアミン四酢酸
Ｂ−８ エチレンジアミン四プロピオン酸
Ｂ−９ エチレンジアミン二酢酸二プロピオン酸
Ｂ−１０ エチレンジアミン二酢酸
Ｂ−１１ エチレンジアミン二プロピオン酸
Ｂ−１２ エチレンジアミン−Ｎ−（β−ヒドロキシエチル）−Ｎ，Ｎ′，Ｎ′−三酢酸
【００４０】
Ｂ−１３ エチレンジアミンジオルトヒドロキシフェニル酢酸
Ｂ−１４ ヒドロキシエチルエチレンジアミン三酢酸
Ｂ−１５ １，２−ジアミノシクロヘキサン四酢酸
Ｂ−１６ メタフェニレンジアミン四酢酸
Ｂ−１７ メタキシリ−レンジアミン四酢酸
Ｂ−１８ トリエチレンテトラミン六酢酸
Ｂ−１９ ニトリロ三酢酸
Ｂ−２０ ニトリロ三プロピオン酸
Ｂ−２１ ニトリロジ酢酸モノプロピオン酸
Ｂ−２２ ニトリロジ酢酸モノヒドロキシプロピオン酸
Ｂ−２３ ニトリロモノ酢酸２プロピオン酸
Ｂ−２４ ニトリロモノ酢酸ジヒドロキシプロピオン酸
Ｂ−２５ イミノジ酢酸
【００４１】
Ｂ−２６ ジヒドロキシエチルグリシン
Ｂ−２７ Ｎ，Ｎ−ビス（２−ヒドロキシエチル）グリシン
Ｂ−２８ アニシジンブルー
Ｂ−２９ クロマズロールＳ
Ｂ−３０ フルオキシン
Ｂ−３１ メチルチモールブルー
Ｂ−３２ メチルキシレノールブルー
Ｂ−３３ サーコシンクレゾールレッド
Ｂ−３４ スチルベンフルオブルーＳ
【００４２】
【化１】

【００４３】
【化２】

【００４４】
【化３】

【００４５】
【化４】

【００４６】
【化５】

【００４７】
さらに、次ぎのものもあげられる。
Ｂ−５４ Ｎ−（２−アセトアミド）イミノ二酢酸
Ｂ−５５ メチルイミノ二酢酸
Ｂ−５６ ヒドロキシエチルイミノ二酢酸
Ｂ−５７ エチレンジアミン−Ｎ，Ｎ′−ジ（２−アセトアミド）二酢酸
Ｂ−５８ ｔｒａｎｓ−１，２−シクロヘキサンジアミン−Ｎ，Ｎ′−ジ（２−アセトアミド）二酢酸
Ｂ−５９ ｏ−キシレンジアミン四酢酸
Ｂ−６０ １，３−プロピレンジアミン−Ｎ−（２−カルボキシフェニル）−Ｎ，Ｎ′，Ｎ′−三酢酸
Ｂ−６１ エチレンジアミン−Ｎ，Ｎ′−ジマロン酸
Ｂ−６２ １，３−プロピレンジアミン−Ｎ，Ｎ′−ジマロン酸
Ｂ−６３ エチレンジアミン−Ｎ，Ｎ′，Ｎ′−三酢酸−Ｎ−モノプロピオン酸
Ｂ−６４ １，３−プロピレンジアミン−Ｎ，Ｎ′，Ｎ′−三酢酸−Ｎ−モノプロピオン酸
Ｂ−６５ ２−｛［１−（カルボキシエチル）−カルボキシメチルアミノ］エチル｝− カルボキシメチルアミノ安息香酸
【００４８】
Ｂ−６６ ２−（１−カルボキシ−２−フェニル−エチルアミノ）−コハク酸
Ｂ−６７ ２−［１−カルボキシ−２−（１Ｈ−イミダゾール−４−イル−エチルアミノフェニル−エチルアミノ］−コハク酸
Ｂ−６８ ２−［（カルボキシ−フェニル−メチル）−アミノ］−コハク酸
Ｂ−６９ ２−（１−カルボキシ−エチルアミノ）−コハク酸
Ｂ−７０ ２−（１−カルボキシ−プロピルアミノ）−コハク酸
Ｂ−７１ ２−（ビス−カルボキシメチル−アミノ）−プロピオン酸
Ｂ−７２ イミノ二コハク酸
本発明のＥＤＴＡ分解菌による生物処理方法は、好ましくは可溶性鉄の存在下で行うのが好ましく、特に可溶性鉄１０〜３０００ｐｐｍ の存在下で行うのがよい。可溶性鉄としては、硫酸第一鉄、塩化第二鉄、硝酸第二鉄等があげられる。
【００４９】
【発明の効果】
本発明の有機アミノカルボン酸類分解菌は、高い塩濃度の廃液中で生存可能であり、有機アミノカルボン酸のナトリウム塩やマグネシウム塩を効果的に分解できる。このうち、Ｂａｃｉｌｌｕｓ ｅｄｉｔａｂｉｄｕｓ −Ｍ１は塩濃度１〜５重量％で増殖が顕著であるが、Ｂａｃｉｌｌｕｓ ｅｄｉｔａｂｉｄｕｓ −Ｍ２は、塩濃度１〜１３重量％で増殖が顕著であり、又Ｍｅｓｏｐｈｉｌｏｂａｃｔｅｒ ｅｄｉｔａｂｉｄｕｓ−Ｍ３も塩濃度１〜１１重量％で増殖が顕著であるので、特にＭ２及びＭ３が有機アミノカルボン酸類を含有する高い塩濃度の廃液の処理に好適である。又、本発明の有機アミノカルボン酸類分解菌は、可溶性鉄が存在しなくとも有機アミノカルボン酸のナトリウム塩やマグネシウム塩を効果的に分解できる。
次ぎに実施例により本発明を説明する。
【実施例】
実施例１
ＥＤＴＡ−塩類を含む下記培養液１５０ｍｌを１２０℃で２０分間オートクレーブにて殺菌後、この培地を５０ｍｌずつの３部に分け、各々にバチルス・エディタビダスＭ−１（ Ｂａｃｉｌｌｕｓ ｅｄｉｔａｂｉｄｕｓ Ｍ−１ ） 、バチルス・エディタビダスＭ−２（ Ｂａｃｉｌｌｕｓ ｅｄｉｔａｂｉｄｕｓ Ｍ−２ ）、およびメソフィロバクター・エディタビダスＭ−３（ Ｍｅｓｏｐｈｉｂｂａｃｔｅｒ ｅｄｉｔａｂｉｄｕｓ Ｍ−３）を接種し、３０℃で１４日間静置培養を行なった。特に遮光しなかった。
培養液組成
ポリペプトン ０．５％
酵母エキス ０．１
ＥＤＴＡ−Ｆｅ ０．０２
人工海水（Ｊａｍａｒｉｎ Ｓ：ジャマリンラボラトリー製）
尚、ＥＤＴＡ−Ｆｅはエチレンジアミン四酢酸アンモニウム２水塩の形で上記濃度になるように添加したものである。
バチルス・エディタビダスＭ−１は、岩手県大槌湾の海泥から分離した。すなわちＥＤＴＡを含む培地を試験管に分注し、滅菌後、海泥を添加し、２７℃で振盪培養した。その後寒天培地を用いて本菌体を得た。
バチルス・エディタビダスＭ−２は岩手県大槌湾の海藻から分離した。海藻を乳鉢にてすりつぶした後、上記Ｍ−１を分離した海泥と同様の操作により本菌体を得た。
メソフィロバクター・エディタビダスＭ−３は神奈川県油壺湾から採取したウニから分離した。ウニを乳鉢にてすりつぶした後上記Ｍ−２と同様にして本菌体を得た。
静置培養後ＥＤＴＡ−Ｆｅの残存度をイオンクロマト法により求めた。
結果を表−１に示す。（ ）内は分解率である。

実施例２
培養条件を振盪条件にて行なった以外は実施例１と同様にして行なった。
結果を表−２に示す。

【００５０】
実施例３
有機アミノポリカルボン酸を含む下記培養液３００ｍｌを１２０°で２０分間オートクレーブにて殺菌後１００ｍｌずつの３部に分け、この培地各々に本発明のＥＤＴＡ分解菌バチルス・エディタビダスＭ−１、バチルス・エディタビダスＭ−２、又はメソフィロバクター・エディタビダスＭ−３を接種し、２７℃で１０日間振盪培養（時々振とう）を行った。特に遮光しなかった。
培養液組成
ポリペプトン ０．５％
酵母エキス ０．１
ＰＤＴＡ−Ｆｅ ０．０１
人工海水（ジャマリンＳ） ３００ｍｌ
尚、ＰＤＴＡ−Ｆｅ は、１，３−ジアミノプロパン四酢酸第二鉄アンモウム塩の形で上記濃度になるように添加したものである。
又、ＰＤＴＡ−Ｆｅ をＢＤＴＡ−Ｆｅ およびＥＤＤＳ−Ｆｅに代えた培養液についても同様に培養を行った。尚、ＢＤＴＡ−Ｆｅ は、ブチレンジアミン四酢酸、塩化第二鉄及びアンモニア（各当モルずつ）の形で上記濃度になるように添加したものである。又、ＥＤＤＳ−Ｆｅは、エチレンジアミンコハク酸、塩化第二鉄及びアンモニア（各当モルずつ）の形で上記濃度になるように添加したものである。ＰＤＴＡ−Ｆｅ 、ＢＤＴＡ−Ｆｅ 及びＥＤＤＳ−Ｆｅについての分解率を実施例１と同様にして評価した（イオンクロマト法）。結果を表−３に示す。

【００５１】
実施例４（担体に付着固定したＥＤＴＡ分解菌によるＥＤＴＡの分解）
３００ｍｌ三角フラスコ中に入れたＥＤＴＡ一塩類を含む下記培養液１００ｍｌと珪藻土１０ｇを１２０°で２０分間オートクレーブにて殺菌後、この培地に本発明のＥＤＴＡ分解菌バチルス・エディタビダスＭ−２を接種し、３０℃で１０日間振盪培養を行った。特に遮光しなかった。
培養液組成
ポリペプトン ０．５％
酵母エキス ０．１
ＥＤＴＡ−Ｆｅ ０．０１
人工海水（ジャマリンＳ） １００ｍｌ
振盪培養後、ＥＤＴＡ−Ｆｅ の残存度及び分解率をイオンクロマト法により求めた。結果を担体がない場合も含めて表−４に示す。
【００５２】

このように、ＥＤＴＡ分解菌を用いた本発明の方法によれば、ＥＤＴＡを優れた分解率で生分解することができる。
また、ＥＤＴＡ分解菌を担体に付着固定させた方がＥＤＴＡの分解能が向上することがわかる。
同様にしてバチルス・エディタビダスＭ−１、メソフィロバクター・エディタビダスＭ−３を担体を用い作用させたところＥＤＴＡの分解率が向上した。
【００５３】
実施例５
ボイラの酸洗浄廃液（モデル液）中のＥＤＴＡの処理
ボイラの酸洗浄廃液がボイラ廃水に混入することを想定してボイラ廃水モデル液を調製した。このモデル液中にはＥＤＴＡ・Ｎａ０．８ｇ／リットル、クエン酸アンモニウム０．３５ｇ／リットルを含み、ＣＯＤ９００ｐｐｍ であった。
前処理（生物処理）：モデル液をアンスラサイトを充填し、好気的に維持した生物濾過塔を通過させることにより、クエン酸を処理した。ＨＲＴ５時間で処理後のＣＯＤは７００ｐｐｍ であった。
ＥＤＴＡ分解菌処理：上記の処理で得られた液を、本発明のＥＤＴＡ分解菌バチルス・エディタズダスＭ−１を付着固定させた粒状活性炭（東洋カルゴン（株）活性炭Ｆ４００）を充填した処理塔に循環させて１サイクル３日の回分式処理を行なった。処理塔内部は散気管からの曝気により好気的に保たれており、１サイクル毎の放流量は処理槽内液の８割とした。処理後液中のＥＤＴＡはかなりの部分が分解されＣＯＤは２０ｐｐｍ であった。
同様にしてバチルス・エディタビダスＭ−２、メソフィロバクター・エディタビダスＭ−３を用いたところＣＯＤはそれぞ３５ｐｐｍ 、２４ｐｐｍ となった。
このように、本発明による方法により種々の廃液中のＥＤＴＡの分解をＥＤＴＡ以外の成分を除くための前処理と組み合わせることによりなしとげることができる。
【００５４】
実施例６
写真処理廃液（銀回収系廃液と現像液系廃液の混合１０倍希釈液）中のＥＤＴＡの処理
銀回収系廃液（カラー写真処理ＣＮ−１６用定着液、ＣＮ−１６Ｑ用漂白液と定着液の混合液、ＣＰ−２０用漂白定着液、ＣＰ−２３用漂白定着液、および黒白写真処理定着液富士Ｆ、ＧＲ−Ｆ１の廃液および水を各々４、１、３、２、７、３、２の比で混合した後銀回収処理を施したもの）と現像液系廃液（カラー写真処理ＣＮ−１６、ＣＮ−１６Ｑ、ＣＰ−２０、ＣＰ−２３各々の発色現像液および黒白写真処理現像液ＲＤ３、ＧＲ−Ｄ１の廃液および水を各々４、１、３、２，７、３、２の比で混合したもの）とを体積比で１対１で混合した。この溶液は無機塩濃度が１２％と高く、通常の活性汚泥処理に適しないため水道水にて１０倍に希釈した。この溶液にリンをリン酸一水素二カリウムの形でＣＯＤ値（約４７００ｐｐｍ）の約２％に相当する量を添加した。更にカルシウムイオンとマグネシウムイオンを各々１０ｐｐｍ 、２ｐｐｍ 添加した。このように調製された廃液のｐＨは８．５であった。
上記した各液についてアンダーラインを付した記号のものはいずれも富士写真フイルム（株）の処理液の商品名である。
【００５５】
先に調製した廃液を以下に示す工程により生物処理を施した。
活性汚泥処理：まず初めにこの廃液をイオウ酸化菌を含む活性汚泥（ＭＬＳＳ４５００ｐｐｍ）にて連続処理を行なった。イオウ酸化菌を含む活性汚泥としては、銀回収系廃液１０倍希釈液（ＣＯＤ約４５００ｐｐｍ）を連続的に滞留時間２日で１ケ月与えることにより馴養したものを用いた。滞留時間は２日であった。
生成する硫酸を１０％水酸化ナトリウム水溶液で中和し、ばっ気槽内の液がｐＨ６．６以下にならないように保った。ｐＨ調節にはｐＨコントローラ（東京理化製ＦＣ−１０型）を用いた。
【００５６】
この処理によりＣＯＤ８３０ｐｐｍ の液が得られた。処理温度は室温であり、以下の実施例においても同様である。
硝化：上述の工程を経た廃液中のアンモニウムイオン（約１０００ｐｐｍ）を、ひも状担体（ＴＢＲ（株）バイオコード）を硝化菌の固定床とした硝化槽を用いて硝酸イオンに変換した。硝化は、硝化槽のｐＨを約７．５に調節しながら、１サイクル２日の回分式処理で行なった。処理槽からの処理液の１サイクル毎の放流量は全量の７割とした。
嫌気処理：上述の工程で得られた硝化液を、粒状活性炭（東洋カルゴン（株）活性炭Ｆ４００）を担体とした嫌気性の流動床を用い１サイクル４日の回分式処理で処理した。処理槽からの処理液の１サイクル毎の放流量は全量の８割とした。処理液のＣＯＤは約２００ｐｐｍ であり、イオンクロマトグラフィーによる分析の結果、含まれる有機成分のほとんどがＥＤＴＡであった。
【００５７】
ＥＤＴＡ分解菌処理：このようにして得られた、ＥＤＴＡを主成分とする溶液を、本発明のＥＤＴＡ分解菌バチルス・エディタビダスＭ−１を付着固定させた多孔性セラミクス担体（東名実業（株）ＣＢ濾材）を処理塔容積の６０ｖｏｌ／ｖｏｌ ％充填した処理塔に循環させて１サイクル２．５日の回分式処理で処理した。処理塔底部に設けた散気管から常時空気を送り込み処理塔内を好気的に保った。
処理槽からの処理液の１サイクル毎の放流量は全部の８割とした。ＥＤＴＡ分解菌を用いた処理により液中のＥＤＴＡはほとんど分解され、処理後のＣＯＤは１２ｐｐｍ であった。同様の実験をバチルス・エディタビダスＭ−２、メソフィロバクター・エディタビダスＭ−３について行なったところ処理後のＣＯＤはそれぞれ１８ｐｐｍ 、１１ｐｐｍ となった。
【００５８】
脱窒：以上の処理により得られた液中の硝酸イオン（ＮＯ_３ −Ｎとして７７０ｐｐｍ ）を、アンスラサイトを担体として充填した固定床式生物脱窒塔に通液することにより、脱窒を行なった。脱窒に必要な有機物としてメタノールをＴＯＣとして１８５０ｐｐｍ（ＴＯＣ／ＮＯ_３ −Ｎ≒２．４／１）になるように添加した。脱窒処理後の液を好気的に保っ生物濾過塔に通液させることにより、残存する有機物を除去した。滞留時間は脱窒塔、好気生物濾過の各々において１２時間、４時間であった。得られた液のＣＯＤは１０ｐｐｍ であった。
鉄除去：以上の工程で得られた液に水酸化ナトリウム１０％水溶液を加えてｐＨ８にした後１５分間攪拌した。凝集剤（大日本インキ（株）リューフロックＡ−５００）を加えて３０分間攪拌した後、生じた赤色沈澱を濾過で除いた。得られた液のＣＯＤは９ｐｐｍ であった。
【００５９】
実施例７
ＥＤＴＡ分解菌（バチルス・エディタビダスＭ−１）を包括固定化して用いた実施例６の処理
実施例６のＥＤＴＡ分解菌処理工程においてＥＤＴＡ分解菌を固定化した担体として多孔性セラミクスの代わりにＥＤＴＡ分解菌（バチルス・エディタビダスＭ−１）を包括固定化したアクリルアミドゲルペレットを用いた。該アクリルアミドゲルは「微生物固定化法による排水処理」須藤隆一編著（産業用水調査会）１９６〜１９９頁に記載の方法で調製した。１片約３ｍｍの立方体に成形した該アクリルアミドゲルを曝気槽容量の約１０％添加し曝気槽内に浮遊流動させて用いた。処理方式は１サイクル２日の回分式処理で、処理槽からの処理液の１サイクル毎の放流量は全量の８割とした。
この処理により液中のＥＤＴＡはほとんど分解され処理後のＣＯＤは１１ｐｐｍ であった。後続の脱窒、鉄除去を実施例６と同様に行なった結果、各々の処理後のＣＯＤは各々９ｐｐｍ 、９ｐｐｍ であった。
またバチルス・エディタビダスＭ−１をバチルス・エディタビダスＭ−２、メソフィロバクター・エディタビダスＭ−３にかえて実験したところ、全く同様の結果が得られた。
【００６０】
実施例８
ＥＤＴＡ分解菌（バチルス・エディタビダスＭ−１）が付着する担体として活性炭を用いた実施例６の処理
実施例６のＥＤＴＡ分解菌処理工程においてＥＤＴＡ分解菌（バチルス・エディタビダスＭ−１）を付着固定化した担体として多孔性セラミクスの代わりに粒状活性炭（東洋カルゴン（株）活性炭Ｆ４００）を処理塔容積６０ｖｏｌ／ｖｏｌ ％用いて処理時間を変えた以外は同様の条件で処理を行なった。
回分式処理を１サイクル１日で行なった結果、液中のＥＤＴＡはほとんど分解され処理後のＣＯＤは４ｐｐｍ であった。
後続の脱窒、鉄除去を実施例６と同様に行なった結果、各々の処理後のＣＯＤは各々３ｐｐｍ 、３ｐｐｍ であった。
実施例６，７，８の結果をまとめて表−５に示す。
【００６１】

またバチルス・エディタビダスＭ−１をバチルス・エディタビダスＭ−２、メソフィロバクター・エディタビダスＭ−３にかえて実験したが、同様の結果が得られた。
表−５に示す実施例６、７及び８の結果からわかるように、ＥＤＴＡ分解菌の固定担体、固定法として色々な種類を用いることが可能である。
本発明による方法により、写真処理廃液を生物処理した後その中のＥＤＴＡの分解を短時間でなしとげることができる。
【００６２】
実施例９
銀回収系廃液中のＥＤＴＡの処理（懸濁液ＭＦ膜濾過法）
実施例６で用いた銀回収系廃液を水で８倍に希釈した。この溶液（ＣＯＤ５８００ｐｐｍ）に実施例６と同様な割合でリン、カルシウムイオン、マグネシウムイオンを添加した後、実施例６と同様にイオウ酸化菌を含む活性汚泥を用いて生物処理を行なった。処理後のＣＯＤは８００ｐｐｍ であった。液中に残存する有機成分のほとんどがＥＤＴＡとＰＤＴＡであった。
ＥＤＴＡ分解菌処理：上記処理で得られた溶液を本発明のＥＤＴＡ分解菌バチルス・エディタビダスＭ−１を液中に懸濁した状態で処理を行なった。ＥＤＴＡ分解菌と処理液との固液分離は、ＭＦ膜（三菱レーヨン（株）ステラポアＳＴＮＭ４２４）を用いて行なった。曝気槽中にこのＭＦ膜でできた中空糸ユニットを沈め、接続したポンプでゆるい吸引を行なうことで清澄な処理液が得られた。懸濁液のＭＬＳＳ（活性汚泥浮遊物）は約７５００ｐｐｍ であった。ＨＲＴ（水理学的滞留時間）３日の連続式処理の結果、液中のＥＤＴＡとＰＤＴＡのかなりの部分が分解されて処理後のＣＯＤは３０ｐｐｍ であった。
【００６３】
懸濁液からの固液分離に沈降槽を用いた場合、ＭＬＳＳは約３０００ｐｐｍ であった。その他の条件をＭＦ膜と同様にして処理した結果、処理後のＣＯＤは８０ｐｐｍ であった。結果を下記表−６に示した。
硝化：ＭＦ膜を用いた処理により得られた処理液を水で２倍に希釈した。この液中に含まれるアンモニウムイオン（約１０００ｐｐｍ）を、実施例６の硝化工程と同様な処理により硝酸イオン（約３４００ｐｐｍ）に変換した。
更に、脱窒と鉄除去を実施例６と同様に行なった結果、各々の処理後のＣＯＤは各々３２ｐｐｍ 、２９ｐｐｍ であった。
一方、本実験に用いたバチルス・エディタビダスＭ−１をバチルス・エディタビダスＭ−２、メソフィロバクター・エディタビダスＭ−３に代えて行なったところ、同様な結果が得られた。
【００６４】
【表９】

表−６に示す結果からわかるようにＥＤＴＡ分解菌を懸濁状態で用いた場合、ＭＦ膜で固液分離することにより、懸濁液の菌体濃度が増加し、かつ処理能が向上する。本発明による方法により、写真処理により排出される銀回収系廃液を生物処理した後、その中のＥＤＴＡの分解を短時間でなしとげることができる。
【００６５】
実施例１０
銀回収系廃液２倍希釈液中のＥＤＴＡの処理（懸濁液限外濾過法）
実施例６で用いた銀回収系廃液を海水で１．８倍に希釈した（塩濃度 約１２％）。この溶液（ＣＯＤ ２５５００ｐｐｍ ）にリンをリン酸一水素二カリウムの形でＣＯＤ値の約１％に相当する量を添加した。このようにして調製した廃液に以下に示す工程により生物処理を施した。
活性汚泥処理：第２７回衛生工学研究討論会論文集（１９９１年）１８３〜１９３頁に記載されている膜分離高濃度活性汚泥法を用いて処理した。すなわち、高濃度の海洋性活性汚泥を用いて処理した後、懸濁物と処理液との固液分離をＵＦ膜を用いて行った。海洋性活性汚泥は銀回収廃液を海水で１０倍に希釈した液を暴気することにより液中で増殖した細菌を用い調製した。前述の調製した廃液中に海洋性活性汚泥を懸濁した状態で処理した。処理はｐＨコントローラーで懸濁液のｐＨが７．５以下にならないように調節した以外は、上記論文集に記載の方法と同様にして行った。懸濁液のＭＬＳＳは約３７０００ｐｐｍ であった。ＨＲＴ７日の連続処理の結果、処理後のＣＯＤは４２００ｐｐｍ であった。液中に残存する有機成分のほとんどがＥＤＴＡとＰＤＴＡであった。
ＥＤＴＡ分解菌処理：上記処理により得られた溶液にＥＤＴＡ分解菌バチルス・エディタビダスＭ−１を懸濁した状態で、実施例９に記載の方法と同様にして処理を行った。
懸濁液のＭＬＳＳは約１５０００ｐｐｍ であった。ＨＲＴ２日の連続式処理の結果、液中のＥＤＴＡとＰＤＴＡのかなりの部分が分解されて処理後のＣＯＤは１１０ｐｐｍ であった。
また、バチルス・エディタビダスＭ−２、メソフィロバクター・エディタビダスＭ−３を用い処理したところ、Ｍ−１より処理率は低下したがいずれも処理後のＣＯＤは１４０ｐｐｍ 以下と良好であった。
このように、本発明のバチルス・エディタビダスＭ−１、バチルス・エディタビダスＭ−２、メソフィロバクター・エディタビダスＭ−３は、高塩濃度の廃液中にも適用可能であり、希釈水とスペースを節約でき処理コストの低減が可能となる。
実施例１１
実施例３の有機アミノポリカルボン酸をＥＤＴＡ・２ＮａおよびＥＤＴＡ−Ｍｇにそれぞれ換えた培養液を調製し、更に食塩を加えることで塩濃度を１０％とした。これらの液に実施例３と同様にしてＥＤＴＡ分解菌を接種し、２７℃で１０日間振盪培養を行なった。分解率は実施例１と同様にして求めた。結果を表−７に示す。
【表１０】

次にＥＤＴＡ・２Ｎａを各種金属（Ｃａ、Ｃｕ、Ｚｎ、Ｐｂ、Ｍｎ、Ｎｉ）のＥＤＴＡキレートに換え、同様に分解率を求めたところ、本発明の３種の菌はいずれも６０％以上の分解率を示した。
従来公知の土壌菌である有機アミノカルボン酸分解菌を用いた場合、有機アミノカルボン酸のＮａ塩やＭｇ塩の分解が見られないのに対し、本発明の海洋細菌であるＥＤＴＡ分解菌はそれらを効率良く分解できることがわかる。[0001]
[Industrial application fields]
The present invention relates to bacteria that degrade organic aminocarboxylic acids (for example, ethylenediaminetetraacetic acid (hereinafter referred to as EDTA)) that are used in large quantities in various industries, and harmless waste liquid containing organic aminocarboxylic acids using the same. The present invention relates to a processing method.
[0002]
[Prior art]
Organic aminocarboxylic acids such as EDTA are mainly used for paper (bleaching), fiber (dyeing aid), detergents such as soap synthetic detergents, cleaning agents for cleaning boilers, machine metal surfaces, glass surfaces, etc., plating, photographs and their Used in various fields such as treatment liquids, cosmetics, food (stabilizer), chemicals (stabilizer), synthetic rubber (polymerizer), vinyl chloride resin (heat stabilizer). Etc. cannot be discharged into nature as they are, and some sort of waste liquid detoxification treatment is applied.
Examples of waste liquid detoxification treatment include biological methods using microorganisms such as activated sludge method, solid removal by filtration, aggregation, sedimentation, floating foam, flotation, aeration, cooling, freezing, distillation, adsorption, Physicochemical treatments such as removal of dissolved components by ion exchange, electrodialysis, reverse osmosis, neutralization, oxidation-reduction, precipitation formation and the like are known.
In view of equipment costs and operating costs for waste liquid treatment, the biological method is the most advantageous among the above methods. However, organic aminocarboxylic acids such as EDTA are generally hardly biodegradable, and waste liquids containing them cannot be completely detoxified only by a normal activated sludge method.
[0003]
As a technique for biodegrading EDTA, a method using the genus Pseudomonas or Alkaligenes described in JP-A-58-43782, Applied And Environmental Microbiology vol. 56, p. 3346-3353 (1990), a method using the species of the genus Agrobacterium, Applied And Environmental Microbiology vol. 58, no. 2, Feb. 1992, p. A method using Gram-negative isolate described in 671-676 has been proposed. However, the methods described in these documents cannot biodegrade organic aminocarboxylic acids stably and with high decomposition efficiency.
Japanese Patent Application Laid-Open No. 6-261717 discloses a method using an organic aminocarboxylic acid-degrading bacterium, Bacillus editor Vidas, which is a new bacterial species. The disclosed new bacterial species has a salt concentration of 10% by weight. There is a problem that it cannot survive in the above aqueous solution and the sodium salt or magnesium salt of EDTA cannot be decomposed satisfactorily. Japanese Patent Application Laid-Open No. 6-335384 discloses a method using an organic aminocarboxylic acid-degrading bacterium Pseudomonas editorbidus, which also survives in an aqueous solution having a salt concentration of 9% by weight or more. However, there is a problem that the sodium salt or magnesium salt of EDTA cannot be decomposed satisfactorily as in the case of the bacterium disclosed in JP-A-6-261717.
[0004]
[Problems to be solved by the invention]
An object of the present invention is to provide a novel organic aminocarboxylic acid-degrading bacterium that can survive even in an aqueous solution having a salt concentration of 10% by weight or more and that can satisfactorily degrade EDTA sodium and magnesium salts.
Another object of the present invention is to provide a method for decomposing a waste liquid having a salt concentration of 10% by weight or more and containing a sodium salt or magnesium salt of EDTA.
[0005]
[Means for Solving the Problems]
The present invention has been made based on the knowledge that marine bacteria capable of degrading organic aminocarboxylic acids can effectively degrade EDTA sodium and magnesium salts in waste liquids having a salt concentration of 10% by weight or more.
That is, the present invention provides organic aminocarboxylic acid-degrading bacteria Bacillus editavidus and Mesophylobacter editidadus that can survive in an aqueous solution having a salt concentration of 10% by weight. This organic aminocarboxylic acid-degrading bacterium, Bacillus editavidus, is a species to which Bacillus editibidus-M1 (Makuken Kenyaku No. 14868) and Bacillus edititadus-M2 (Mikken Kenyaku No. 14869) belong. . In addition, the organic aminocarboxylic acid-degrading bacterium Mesophylobacter editidadus is a species to which Mesophyllobacter editidas-M3 (Mikoken Bacterium No. 14870) belongs.
[0006]
The present invention also provides a method for treating a waste liquid containing organic aminocarboxylic acids, wherein the organic aminocarboxylic acid-degrading bacterium is mixed with or contacted with a waste liquid containing organic aminocarboxylic acids.
In the present invention, marine bacteria that degrade organic aminocarboxylic acids are mixed or brought into contact with a waste liquid having an inorganic salt concentration of 2% by weight or more and containing sodium and / or magnesium salts of organic aminocarboxylic acids. A method for treating a waste liquid containing organic aminocarboxylic acids is provided.
Organic aminocarboxylic acid-degrading bacteria Bacillus editavidus and Mesophylobacter editidadus that are viable in an aqueous solution having a sodium chloride concentration of 10% by weight used in the present invention are new species, and Bacillus edititadus-M1. (Microtechnological Bacteria No. 14868), Bacillus edititadus-M2 (Microtechnological Bacteria Yoko No. 14869) and Mesophyllobacter dietibusus-M3 (Microtechnological Laboratories No. 14870) are as follows. is there.
[0007]
Bacillus edititadus -Mycological properties of M1
I. Morphological properties
1) Fungus form: Neisseria gonorrhoeae
2) Size: 0.5-0.9 × 1.3-4.1 μm
(Cultivation in nutrient agar at 25 ° C for 48 hours)
3) Spore shape: ellipsoid
4) Spore position: near the end
5) Mobility: Yes
6) Gram staining: Gram positive
II. Culture properties
1) Ordinary agar medium using seawater: good growth, round and translucent glossy orange colony formed, convex at the periphery and flat
[0008]
III. Physiological properties
1) Oxidase test: +
2) Catalase: +
3) O / F test: oxidation
4) Growth temperature: grow even at 45 ° C
5) Growth salt concentration: 0 to 11%
6) Growth under pH 5.7: −
7) Anaerobic growth: +
8) pH in VP broth: 5.2
9) Dye production: +
10) Nitrate: reduction
11) ONPG test:-
12) Esculin hydrolysis: −
13) Decomposition of alginic acid: −
14) Casein degradation: +
15) DNA degradation: +
16) Degradation of gelatin: +
17) Starch decomposition: +
18) Decomposition of Tween 80: +
19) Degradation of tyrosine:-
[0009]
20) Acid production from glucose: +
21) Production of gas from glucose: −
22) Utilizing carbon sources: glycerin, ribose, D-glucose, D-fructose, mannitol, N-acetylglucosamine, esculin, maltose, sucrose, trehalose, starch, glycogen, β-gentibiose
Based on the above bacteriological properties, this strain was identified as a strain belonging to the genus Bacillus by Bergey's Manual of Systematic Bacteriology (Volume 2). Among the genus Bacillus, the most similar to this strain is Bacillus farmus. Among the above properties, nitrate reduction, anaerobic growth, growth at 10% salt concentration, pH in VP broth In addition to being different, it is clearly distinguished from the spread form of the spore that was observed separately. No other Bacillus species were similar to this strain, and thus were identified as new species.
[0010]
Bacillus edititadus -Mycological properties of M2
I. Morphological properties
1) Fungus form: Neisseria gonorrhoeae
2) Size: 0.6 to 1.0 × 1.1 to 4.0 μm
(Cultivation in nutrient agar at 25 ° C for 48 hours)
3) Spore shape: ellipsoid
4) Spore position: from center to near end
5) Mobility: Yes
6) Gram staining: Gram positive
II. Culture properties
1) Ordinary agar medium using seawater: good growth, round and glossy orange colony, flat periphery and convexity
[0011]
III. Physiological properties
1) Oxidase test: +
2) Catalase: +
3) O / F test: oxidation
4) Growth temperature: grow even at 45 ° C
5) Growth salt concentration: 0-15%
6) Growth under pH 5.7: −
7) Anaerobic growth: +
8) pH in VP broth: 5.2
9) Dye production: +
10) Nitrate: reduction
11) ONPG test: +
12) Esculin hydrolysis: −
13) Decomposition of alginic acid: −
14) Casein degradation: +
15) DNA degradation: +
16) Degradation of gelatin: +
17) Starch decomposition: +
18) Decomposition of Tween 80: +
19) Degradation of tyrosine:-
[0012]
20) Acid production from glucose: +
21) Production of gas from glucose: −
22) Carbon sources to be assimilated: glycerin, ribose, D-glucose, D-fructose, mannitol, N-acetylglucosamine, esculin, maltose, sucrose, trehalose, starch, glycogen, β-gentibiose
Based on the above bacteriological properties, this strain was identified as a strain belonging to the genus Bacillus by Bergey's Manual of Systematic Bacteriology (Volume 2). This strain is very similar to M-1, but in the above properties, the ONPG test results are different in addition to the location of the spore and the nature of the colonies on the normal agar medium. This strain was confirmed to be a new strain as well as M-1.
[0013]
Mesophilobacter edititadus -Mycological properties of M3
I. Morphological properties
1) Fungus form: Short bacillus
2) Size: 0.4-0.6 × 0.9-2.0 μm
(Cultured on seawater agar at 25 ° C for 24 hours)
3) Mobility: None
4) Gram staining: Gram negative
II. Culture properties
1) Ordinary agar medium using seawater: good growth, round and glossy yellow colonies, the peripheral part is flat and the convexity is low
[0014]
III. Physiological properties
1) Oxidase test: +
2) Catalase: +
3) O / F test: oxidation, generation of strong acid
4) Growth temperature: Not growing even at 45 ° C
5) Growth salt concentration: 0-12%
6) Penicillin sensitivity:-
7) pH in VP broth: 5.2
8) Production of indole:-
9) Nitrate: Reduction
10) Oxidation of cytochrome: +
11) Esculin hydrolysis: +
12) Decomposition of alginic acid: −
13) Decomposition of urea:
14) Degradation of galactose:-
15) Degradation of gelatin: +
16) Decomposition of starch (seawater):-
17) Decomposition of Tween 80 (seawater):-
18) Degradation of DNA (seawater): +
19) Acid production +: glucose, fructose, mannitol, cellobiose
[0015]
20) Utilizing carbon sources: glucose, mannose, mannitol, N-acetylglucosamine, maltose, gluconate, malate, citrate,
As a result of a literature survey based on the above bacteriological properties, this strain is similar to a strain belonging to the genus Vibrio, but has different motility and viability in a TCBS selective medium. On the other hand, the properties of the new strain of Mesophylobacter genus Marinus described in International Journal of Systemic Bacteriology Vol. 39, No. 4, pp. 378-381 (1989) are very similar, and this strain belongs to Mesophilac. It was judged. However, it is clearly distinguished from marinus because of the above properties, indole production and urea decomposition are different. Therefore, this strain was certified as a new strain.
[0016]
As is apparent from the above mycological properties, the organic aminocarboxylic acid-degrading bacteria Bacillus editorvidus and Mesophyllobacter editorvidus used in the present invention are more effective than the conventional organic aminocarboxylic acid-degrading bacteria. Can grow and be active at a high salt concentration, particularly 10% by weight. This shows the possibility that it can be treated with this bacterium without diluting a waste liquid with a high salt concentration, such as photographic processing waste liquid, and is very preferable for the purpose of the present invention. I can say that.
The bacterium of the present invention is remarkably improved by acclimatization as compared with conventionally known EDTA-degrading bacteria, and can be expected to be decomposed in a shorter period of time than shown in the examples described later.
[0017]
The method for culturing organic aminocarboxylic acid degrading bacteria used in the present invention is described below.
The composition of the medium used for culturing this strain is from a suitable carbon source, nitrogen source, or organic nutrient source inorganic salt, etc., in order for the strain to be used to grow well and to smoothly decompose organic aminocarboxylic acids such as EDTA. Become. As the carbon source, an organic aminocarboxylic acid metal complex (for example, EDTA · Fe or EDTA · Na 3) can be used. Examples of the nitrogen source or organic nutrient source include polypeptone, yeast extract, meat extract and the like. It is preferable to use about 0.1 to 1% of the organic nutrient source. Moreover, various phosphates, magnesium sulfate, etc. can be used as an inorganic salt. Furthermore, although a trace amount of heavy metals are used, a medium containing a natural product does not necessarily require addition. As a preferred medium, Fuji No. 3 medium (polypeptone 0.5%, yeast extract 0.1%, EDTA iron ammonium salt 0.1%, agar 2.0%, artificial seawater (Jamarine S: sold by Jamarin Laboratory Co., Ltd.)).
The culture may be performed by sterilizing the medium by heating or the like, inoculating the bacteria, and allowing to stand at 25 to 39 ° C. for 3 to 10 days, shaking or agitating. The pH is preferably about 6-8.
Confirmation of decomposition of EDTA can be performed by ion chromatography. That is, a solution obtained by filtering the cultured solution with a 0.45 μm Millipore filter is appropriately diluted and subjected to ion chromatography to observe the residual rate.
[0018]
In the present invention, the organic aminocarboxylic acid-degrading bacterium is brought into contact with the organic aminocarboxylic acids to decompose them. In addition, marine bacteria that degrade organic aminocarboxylic acids other than the above-mentioned organic aminocarboxylic acid-degrading bacteria can also be used. Therefore, the method of the present invention can be effectively used as a treatment method for detoxifying waste water containing organic aminocarboxylic acids such as EDTA. These organic aminocarboxylic acids such as EDTA are mainly used for paper (bleaching), fiber (dyeing), detergent, plating, food, photography, cosmetics, medicine, agricultural chemicals, synthetic rubber (polymerizing agent), vinyl chloride resin (heat stabilizer). ), Etc., and EDTA etc. are contained in these factory wastewater and waste liquid. There are strict regulations on factory wastewater and liquid waste. In the photographic processing solution, an organic aminocarboxylic acid such as EDTA or a salt thereof is used as a chelating agent, and ferric complex salt of EDTA or ferric iron of 1,3-propylenediaminetetraacetic acid (hereinafter referred to as PDTA). Complex salts are used as bleaching and reducing agents. Further, an organic aminocarboxylic acid such as EDTA or a salt thereof may be contained as a hard water softener in the photosensitive lithographic processing solution.
In general, it is known that EDTA is the least biodegradable among organic aminocarboxylic acids. Therefore, the present invention will be described below by taking an example of a treatment method for EDTA-containing waste liquid.
[0019]
In the present invention, organic aminocarboxylic acids are biodegraded using a bacterium that decomposes the above organic aminocarboxylic acids (hereinafter referred to as EDTA-degrading bacteria), and the following method is preferable as the biodegradation treatment at that time. Among these, (2) or (3) is more preferable because the decomposition efficiency is greatly improved.
(1) The EDTA-degrading bacterium is mixed or brought into contact with a waste liquid containing organic aminocarboxylic acids.
(2) EDTA-decomposing bacteria are used in a state suspended in a waste liquid containing organic aminocarboxylic acids, and solid-liquid separation is performed using a separation membrane such as an MF membrane or a UF membrane instead of the conventional solid-liquid separation by sedimentation. .
(3) The EDTA-degrading bacterium immobilized in the treatment (1) is used.
[0020]
In (3) of the present invention, the EDTA-degrading bacterium is immobilized and brought into contact with the waste liquid. As a method for immobilizing microorganisms, any method can be applied as long as it is a method for immobilizing EDTA-degrading bacteria from the treatment tank so as not to flow out.
As specific immobilization methods, for example, an attached biofilm method using a carrier on which microorganisms adhere to form a biofilm, a comprehensive immobilization method in which microorganisms are confined in a gel, or the like can be used.
The feature of the attached microbial membrane method is that the concentration of microorganisms can be increased and the processing efficiency can be improved. In addition, in the suspension method, bacteria having a slow growth rate that are washed out of the system can be retained in the system. It is also characterized by its easy maintenance and low sludge generation.
[0021]
Examples of the carrier in the attached biofilm method include porous ceramics, activated carbon, sponge, chitosan, string carrier, plastic, honeycomb carrier, corrugated carrier, mesh carrier, anthracite, gravel, sand, pumice, diatomaceous earth, etc. 1 type (s) or 2 or more types can be used.
The carrier used in the attached biofilm method varies depending on the manufacturer, and any type can be used as long as microorganisms adhere to form a biofilm.
Examples of the porous ceramics include foamed brick, various filter media (for example, CB filter media of Tomei Jigyo Co., Ltd.), Scholax made by Schott Klaske, zeolite, and the like.
The activated carbon may be granular activated carbon, powder activated carbon or fibrous activated carbon. Toyo Calgon F400, Kuraray Chemical Kuraray Coal KW, Kureha Chemical Industries BAC, Toho Rayon FX-300 Can be mentioned.
Examples of the string-like carrier include Toyo Thermy Co., Ltd. Biomall, TBR Co., Ltd. Biocode, and the like.
[0022]
The feature of the entrapping immobilization method is that the bacterial cells can be maintained at a high concentration, so that the treatment efficiency can be improved and the slow-growing bacteria can be immobilized. Moreover, the tolerance with respect to change of conditions, such as pH and temperature, is wide, and it can endure high load operation. Another feature is that the amount of sludge generated is small.
As the comprehensive immobilization method, acrylamide method, agar-acrylamide method, PVA-boric acid method, PVA-freezing method, photo-curing resin method, acrylic synthetic polymer resin method, sodium polyacrylate method, sodium alginate method, Any type of K-carrageenan method or the like can be used as long as it can confine microorganisms and has high physical strength and can withstand long-time use while maintaining the activity of the microorganisms in the treatment tank.
[0023]
As a representative example of the entrapping immobilization method, a method for preparing a microorganism-immobilized gel in the case of the acrylamide method will be described. The immobilization gel suspends an acrylamide monomer solution containing a cross-linking agent (for example, N, N′-methylenebisacrylamide) and activated sludge (concentrated sludge having a MLSS of about 20,000 ppm) to suspend the polymerization accelerator (for example, N , N, N ′, N′-tetramethylethylenediamine) and a polymerization initiator (for example, potassium persulfate) are added to a molded shape such as a 3 mm diameter vinyl chloride tube and polymerized at 20 ° C. to complete the polymerization. After that, it is obtained by extruding from a mold and cutting it into a certain length.
Since the pores on the surface of the immobilized gel are smaller than the bacteria, the entrapped and immobilized bacteria are unlikely to leak, grow inside and self-decompose. Only dissolved components in the wastewater enter the gel through the pores and are treated by the bacteria inside.
[0024]
For more specific methods of these immobilization methods, "Wastewater treatment by microbial immobilization method" written by Ryuichi Sudo (Industrial Water Research Committee), Kohei Inamori "Trends in advanced and efficient wastewater treatment by biofilm method" , Water pollution research, vol. 13, no. 9, 1990, p. 563-574, “The trend / problem / prospect of advanced water treatment technology development” by Satoru Inamori, water and wastewater, vol. 34, no. 10, 1992, p. 829-835.
For treatment using organic aminocarboxylic acid-degrading bacteria, the above-mentioned carrier, immobilized gel, etc. may be suspended and flowed in the treatment tank, or the biological filtration method, the immersion filter bed method, the fluid bed method, the rotation You may use as support | carriers, such as a disk method and a sprinkling filter bed method.
[0025]
In the treatment method of (2) above, in a state where EDTA-degrading bacteria are suspended, they are mixed with an organic aminocarboxylic acid-containing waste liquid for biological treatment. Specifically, there can be mentioned a method in which a large amount of cultured cells are suspended and mixed with waste liquid. In this method, solid-liquid separation is performed using a UF membrane or an MF membrane while mixing and biological treatment or after the biological treatment. This method is characterized in that the sludge concentration (MLSS) in the treatment tank can be maintained high (several thousands to 30,000 ppm) as compared with a solid-liquid separation method using a normal sedimentation tank. UF membranes and MF membranes are characterized in that processing facilities can be made compact and bulking does not occur.
These membrane materials include polyacrylonitrile, polysulfone, cellulose acetate, polyethersulfone, polyolefin, polyimide, and fluorine.
[0026]
As the UF membrane, polysulfone-based membrane materials are available from Asahi Kasei Corporation, Kuraray Co., Ltd., Mitsubishi Rayon Co., Ltd., Nitto Denko Co., Ltd., Sumitomo Bakelite Co., Ltd., Romicon, Amicon, Millipore, etc. Fluorine-based membrane materials are Rhone-Poulenc, Millipore, etc., polyolefin-based membrane materials are from Nitto Denko Corporation, polyimide-based membrane materials are from Nitto Denko Corporation, and PAN-based membrane materials. Are sold by Asahi Kasei Co., Ltd., Daicel Chemical Co., Ltd., Mitsubishi Rayon Co., Ltd., Rhone-Poulenc and others.
Regarding the separation method of treated water using UF membrane, "27th Sanitary Engineering Research Conference Proceedings" (1991), pages 183 to 193, "3rd Water Recycling System Research and Development Results Preliminary Proceedings" ( (1991) 1-19 pages.
Commercially available MF membranes include various Yumicron membranes manufactured by Yuasa Co., Ltd., Millipore filters manufactured by Millipore (for example, Millipore AA, DA, HA, PH, GS, FG, UC, UM, US, GU, HP, etc.) ), Kuraray microfiltration filters (SF-301, SF-101, SF-401), Gore-Tex membranes manufactured by Gore-Tex Corporation, hollow fiber single membrane MF membranes (for example, Kuraray Co., Ltd.) SF filter (material polyvinyl alcohol) pore size 0.1 μm, Asahi Kasei SR-205 (material polyolefin) pore size 0.1 μm, Nitto Denko E202AE (material fluororesin) pore size 0.2 μm, Mitsubishi Rayon Co., Ltd. Sterapore STNM424 (polyethylene) For example, a pore diameter of 0.1 μm).
[0027]
Performing the biological treatment in the above method (2) or (3) in the presence of activated carbon is a preferred embodiment because its decomposition activity is increased. For improving the degradation activity by microorganisms by using activated carbon, Wataru Nishijima et al., “Degradation and removal of low-concentration organic compounds by biological activated carbon”, Journal of Water Environment Society, vol. 15, no. 10, 1992, p. 683-689 can be referred to.
[0028]
Although the contact time and treatment temperature with the EDTA-degrading bacterium in the biological treatment in the above method (2) or (3) can be set arbitrarily, a desired degradation rate can be obtained at a suitable treatment temperature of the EDTA-degrading bacterium. It is better to contact for a certain amount of time. Usually, an aqueous solution at 25 to 39 ° C. containing 0.01 to 9% of organic aminocarboxylic acids is preferably contacted with EDTA-degrading bacteria for about 12 to 240 hours. The pH at this time is preferably 5 to 9, and more preferably 6 to 8. Further, it is preferable to use a waste liquid having a salt concentration of 2 to 20% by weight, preferably 3 to 15% by weight, and most preferably 10 to 12% by weight. Organic aminocarboxylic acids can be used even in the presence of a sodium salt and / or a magnesium salt. Decomposes well.
[0029]
The waste liquid contains various substances other than EDTAs. In the present invention, the EDTA-containing wastewater is preferably subjected to a pretreatment for removing components other than EDTAs before the treatment using EDTA-degrading bacteria. The pretreatment varies depending on the substance contained in the waste liquid and is preferably subjected to a treatment suitable for the waste liquid. Examples of these pretreatments include treatment for decomposing components that can be decomposed by normal biological treatment, physicochemical treatment, and the like.
Examples of the treatment for decomposing components that can be decomposed by normal biological treatment include, for example, an activated sludge method, an anaerobic digestion method or a sponge carrier method, a microorganism suspension method, a biological filtration method, a submerged filter bed method, a fluidized bed method, A biofilm method such as a rotating disk method or a trickling filter method, or a self-granulating method can be used. These treatments may be continuous or batchwise. Moreover, either aerobic and anaerobic may be sufficient, or those combinations may be sufficient.
The activated sludge method is also disclosed in Japanese Patent Publication Nos. 55-49559 and 51-12943.
[0030]
The nitrification and denitrification will be explained.
When the waste water contains inorganic nitrogen compounds such as ammonia, nitrous acid and nitric acid, nitrogen removal can be performed biologically. Nitrous acid and nitric acid are removed as nitrogen by denitrifying bacteria under anaerobic conditions. In the case of ammonia, nitrification is required first, and nitrification is divided into nitritation and nitrification. Nitrite is performed by Nitromonas, and nitrification is performed by Nitrobacter. Nitrite bacteria and nitrate bacteria are collectively called nitrifying bacteria. Since nitrifying bacteria have a low growth rate, it is necessary to prevent the outflow of nitrifying bacteria in order to increase the cell concentration in the treatment tank. For this purpose, for example, a treatment tank using pellets in which the SRT (sludge retention time) in the activated sludge method is maintained for a long time, nitrifying bacteria are attached to the carrier and fixed, or nitrifying bacteria are comprehensively fixed. A method of increasing the concentration of nitrifying bacteria in the inside is mentioned.
Conditions for growing nitrifying bacteria include water temperature, pH, dissolved oxygen, BOD load, alkalinity, nitrogen load, and the like. Particularly important factors are pH, and pH of 6.5 to 8.5 is preferable.
[0031]
In order to denitrify nitric acid and nitrous acid by denitrifying bacteria under anaerobic conditions, an organic compound (organic carbon source) as a hydrogen donor is required. Although organic substances in the raw water can be used as the organic carbon source, methanol, acetic acid, etc. are added if insufficient. In the case of methanol, it is practically nitrate nitrogen (NO₃-N) About 3 times the amount of methanol in terms of BOD is required for 1 kg.
For more specific methods for these biological treatments, see “Biological Water Treatment Technology and Equipment” edited by the Chemical Engineering Association (Baifukan), “Microbiology for Environmental Purification” edited by Ryuichi Sudo (Kodansha Scientific), “ Wastewater treatment process, design theory and experimental method "W. W. Ekkenfelder, D.C. L. It is described in Ford (Gihodo). In addition, when the component decomposed | disassembled by biological treatment other than EDTA is not included, these pre-biological treatments are unnecessary.
[0032]
Physicochemical treatment includes solids removal by filtration, aggregation, sedimentation, floating foam or flotation, aeration, cooling, freezing, distillation, adsorption, ion exchange, electrodialysis, reverse osmosis, neutralization, oxidation (ozone, Chlorine, air, electrolysis, etc.), removal of dissolved components by reduction or precipitation, and the like.
The electrolytic oxidation method is disclosed in JP-A-48-84462, JP-A-49-119458, JP-B-53-43478, JP-A-49-119457, and the ion exchange method is described in JP-B-51-37704 and 53. No. -383, 53-43271, and reverse osmosis methods include JP-A-50-22463.
[0033]
It can be combined with other waste liquid treatment methods for the purpose of placing no burden on the treatment process with EDTA-degrading bacteria. That is, when a chemical treatment method such as Fenton oxidation method using hydrogen peroxide as an oxidizing agent or an electrolysis method is used for the pretreatment, the components to be decomposed in the waste liquid have been decomposed to a certain extent. The purpose can be achieved by performing biological treatment and further treatment with EDTA-degrading bacteria. The chemical oxidation method and the electrolysis method are also described in detail in JP-A-4-16289, 4-18986, 4-197487, 4-235787, and the like, respectively.
[0034]
On the other hand, depending on the component content of the waste liquid, EDTA or the like may be treated with EDTA-degrading bacteria, and then difficult-to-decompose components may be degraded by other means. First, after treatment with EDTA-degrading bacteria, as shown above Examples include biological treatment or chemical oxidation method, electrolysis method, adsorption (by activated carbon or the like), ion exchange method or the like.
In addition, it is preferable to perform the removal process of an iron component, the removal process of nitrogen, and phosphorus as needed after the above processing process. As for iron removal, a method in which the treatment liquid is made alkaline to insolubilize and remove iron ions, or at a pH of 4 to 7.5, iron ions are precipitated and removed as a complex salt with phosphate and / or other inorganic salt / acid. These are described in detail in JP-A-4-235787. Nitrogen and phosphorus removal is described in detail in "New activated sludge method" (Industrial Water Research Committee).
[0035]
A typical flow of the waste liquid treatment of the present invention is shown below. In addition, the process of the said method (2) and (3) is combined and shown as EDTA degradation bacteria process. In the case of a photographic processing waste liquid, the following processing methods 5, 6, 7 and 10-13 are preferred.
[0036]
[Table 1]

[0037]
[Table 2]

[0038]
[Table 3]

[0039]
According to the present invention, various organic aminocarboxylic acids can be decomposed. Examples of organic aminocarboxylic acids to be decomposed include organic acid free acids or salts thereof (for example, salts with alkali metals such as sodium and potassium, ammonium and alkanolamine) and metal complexes thereof such as iron, Metal complexes with copper, calcium, magnesium, cobalt, manganese, gold and the like can be mentioned.
Typical examples of the organic aminocarboxylic acid (free acid) or a salt thereof are listed below.
B-1 Ethylenediaminetetraacetic acid (EDTA)
B-2 Diethylenetriaminepentaacetic acid
B-3 1,2-Diaminopropanetetraacetic acid
B-4 1,3-Diaminopropanetetraacetic acid (PDTA)
B-5 Butylene diamine tetraacetic acid (BDTA)
B-6 Ethyl ether diamine tetraacetic acid
B-7 Glycol ether diamine tetraacetic acid
B-8 Ethylenediaminetetrapropionic acid
B-9 Ethylenediaminediacetic acid dipropionic acid
B-10 Ethylenediaminediacetic acid
B-11 Ethylenediamine dipropionic acid
B-12 Ethylenediamine-N- (β-hydroxyethyl) -N, N ′, N′-triacetic acid
[0040]
B-13 Ethylenediaminediorthydroxyphenylacetic acid
B-14 Hydroxyethylethylenediaminetriacetic acid
B-15 1,2-Diaminocyclohexanetetraacetic acid
B-16 Metaphenylenediaminetetraacetic acid
B-17 Metaxylylenediamine tetraacetic acid
B-18 Triethylenetetramine hexaacetic acid
B-19 Nitrilotriacetic acid
B-20 nitrilotripropionic acid
B-21 Nitrilodiacetic acid monopropionic acid
B-22 nitrilodiacetic acid monohydroxypropionic acid
B-23 Nitrilomonoacetic acid 2-propionic acid
B-24 Nitrilomonoacetic acid dihydroxypropionic acid
B-25 Iminodiacetic acid
[0041]
B-26 Dihydroxyethylglycine
B-27 N, N-bis (2-hydroxyethyl) glycine
B-28 Anisidine Blue
B-29 Chromazurol S
B-30 Fluoxin
B-31 Methylthymol Blue
B-32 Methylxylenol Blue
B-33 Circosincresol Red
B-34 Stilbene Fluoro Blue S
[0042]
[Chemical 1]

[0043]
[Chemical 2]

[0044]
[Chemical 3]

[0045]
[Formula 4]

[0046]
[Chemical formula 5]

[0047]
In addition, the following are also included.
B-54 N- (2-acetamido) iminodiacetic acid
B-55 Methyliminodiacetic acid
B-56 Hydroxyethyliminodiacetic acid
B-57 Ethylenediamine-N, N'-di (2-acetamido) diacetic acid
B-58 trans-1,2-cyclohexanediamine-N, N'-di (2-acetamido) diacetic acid
B-59 o-xylenediaminetetraacetic acid
B-60 1,3-propylenediamine-N- (2-carboxyphenyl) -N, N ', N'-triacetic acid
B-61 Ethylenediamine-N, N'-dimalonic acid
B-62 1,3-propylenediamine-N, N′-dimalonic acid
B-63 Ethylenediamine-N, N ', N'-triacetic acid-N-monopropionic acid
B-64 1,3-propylenediamine-N, N ', N'-triacetic acid-N-monopropionic acid
B-65 2-{[1- (carboxyethyl) -carboxymethylamino] ethyl} -carboxymethylaminobenzoic acid
[0048]
B-66 2- (1-carboxy-2-phenyl-ethylamino) -succinic acid
B-67 2- [1-Carboxy-2- (1H-imidazol-4-yl-ethylaminophenyl-ethylamino] -succinic acid
B-68 2-[(Carboxy-phenyl-methyl) -amino] -succinic acid
B-69 2- (1-Carboxy-ethylamino) -succinic acid
B-70 2- (1-carboxy-propylamino) -succinic acid
B-71 2- (bis-carboxymethyl-amino) -propionic acid
B-72 Iminodisuccinic acid
The biological treatment method using an EDTA-degrading bacterium of the present invention is preferably performed in the presence of soluble iron, particularly in the presence of 10 to 3000 ppm of soluble iron. Examples of the soluble iron include ferrous sulfate, ferric chloride, and ferric nitrate.
[0049]
【The invention's effect】
The organic aminocarboxylic acid-degrading bacterium of the present invention can survive in a waste liquid with a high salt concentration, and can effectively decompose the sodium salt and magnesium salt of the organic aminocarboxylic acid. Among these, Bacillus editabidos-M1 is prominently proliferated at a salt concentration of 1 to 5% by weight, whereas Bacillus editabidus-M2 is prominently proliferated at a salt concentration of 1 to 13% by weight, and Mesophyllobacter dietidas-M3 is also a salt. Since the growth is remarkable at a concentration of 1 to 11% by weight, M2 and M3 are particularly suitable for the treatment of a waste solution having a high salt concentration containing organic aminocarboxylic acids. In addition, the organic aminocarboxylic acid-degrading bacterium of the present invention can effectively decompose the sodium salt or magnesium salt of organic aminocarboxylic acid without the presence of soluble iron.
Next, the present invention will be described with reference to examples.
【Example】
Example 1
After sterilizing the following culture solution containing EDTA-salts in an autoclave at 120 ° C. for 20 minutes in an autoclave, the medium was divided into three portions of 50 ml each, Bacillus editors Vidus M-1 (Bacillus editidas M-1), Bacillus Editor Vidas M-2 (Bacillus editabius M-2) and Mesophyllobacter editor Vidas M-3 (Mesophybacter editidas M-3) were inoculated, and static culture was performed at 30 ° C. for 14 days. In particular, it was not shaded.
Culture solution composition
Polypeptone 0.5%
Yeast extract 0.1
EDTA-Fe 0.02
Artificial seawater (Jamarin S: manufactured by Jamarin Laboratory)
In addition, EDTA-Fe is added so that it may become the said density | concentration in the form of ethylenediaminetetraacetic acid ammonium dihydrate.
Bacillus Editor Vidas M-1 was separated from the sea mud in Otsuchi Bay, Iwate Prefecture. That is, a medium containing EDTA was dispensed into a test tube, sterilized, sea mud was added, and cultured with shaking at 27 ° C. Thereafter, the cells were obtained using an agar medium.
Bacillus Editor Vidas M-2 was isolated from seaweed in Otsuchi Bay, Iwate Prefecture. After the seaweed was ground in a mortar, the cells were obtained by the same operation as the sea mud from which M-1 was separated.
Mesophylobacter / Editor Vidas M-3 was isolated from sea urchin collected from Aburatsubo Bay, Kanagawa Prefecture. After the sea urchin was ground in a mortar, the cells were obtained in the same manner as M-2.
After static culture, the residual level of EDTA-Fe was determined by ion chromatography.
The results are shown in Table-1. Figures in parentheses are decomposition rates.

Example 2
This was carried out in the same manner as in Example 1 except that the culture was performed under shaking conditions.
The results are shown in Table-2.

[0050]
Example 3
300 ml of the following culture solution containing organic aminopolycarboxylic acid was sterilized at 120 ° for 20 minutes in an autoclave and then divided into three portions of 100 ml each. M-2 or Mesophylobacter editor Vidas M-3 was inoculated and cultured at 27 ° C. for 10 days with shaking (sometimes shaking). In particular, it was not shaded.
Culture solution composition
Polypeptone 0.5%
Yeast extract 0.1
PDTA-Fe 0.01
Artificial seawater (Jamarine S) 300ml
In addition, PDTA-Fe is added to the above concentration in the form of 1,3-diaminopropanetetraacetic acid ferric ammonium salt.
Further, the culture was performed in the same manner with respect to a culture solution in which PDTA-Fe was replaced with BDTA-Fe and EDDS-Fe. In addition, BDTA-Fe is added so that it may become the said density | concentration in the form of butylene diamine tetraacetic acid, ferric chloride, and ammonia (each equimolar amount). Moreover, EDDS-Fe is added so that it may become the said density | concentration in the form of ethylenediamine succinic acid, ferric chloride, and ammonia (each equimolar amount). The decomposition ratios for PDTA-Fe, BDTA-Fe and EDDS-Fe were evaluated in the same manner as in Example 1 (ion chromatography method). The results are shown in Table-3.

[0051]
Example 4 (Degradation of EDTA by EDTA-degrading bacteria adhered and immobilized on a carrier)
100 ml of the following culture solution containing EDTA monosalt contained in a 300 ml Erlenmeyer flask and 10 g of diatomaceous earth were sterilized in an autoclave at 120 ° for 20 minutes, and this medium was inoculated with the EDTA-degrading bacterium Bacillus editor Vidas M-2 of the present invention. The shaking culture was performed at 30 ° C. for 10 days. In particular, it was not shaded.
Culture solution composition
Polypeptone 0.5%
Yeast extract 0.1
EDTA-Fe 0.01
Artificial seawater (Jamarine S) 100ml
After shaking culture, the residual degree and decomposition rate of EDTA-Fe were determined by ion chromatography. The results are shown in Table 4 including the case where there was no carrier.
[0052]

Thus, according to the method of the present invention using EDTA-degrading bacteria, EDTA can be biodegraded with an excellent degradation rate.
It can also be seen that the resolution of EDTA is improved by attaching and fixing EDTA-degrading bacteria to the carrier.
Similarly, when Bacillus editor Vidas M-1 and Mesophylobacter editor Vidas M-3 were allowed to act using a carrier, the decomposition rate of EDTA was improved.
[0053]
Example 5
Treatment of EDTA in acid washing waste liquid (model liquid) of boiler
A boiler wastewater model liquid was prepared assuming that the acid cleaning wastewater of the boiler was mixed into the boiler wastewater. This model solution contained EDTA / Na 0.8 g / liter and ammonium citrate 0.35 g / liter, and the COD was 900 ppm.
Pretreatment (biological treatment): Citric acid was treated by passing the model solution through a biofiltration tower filled with anthracite and maintained aerobically. The COD after treatment at HRT for 5 hours was 700 ppm.
EDTA-decomposing bacteria treatment: The liquid obtained by the above-mentioned treatment is circulated to a treatment tower packed with granular activated carbon (Toyo Calgon Co., Ltd. activated carbon F400) to which the EDTA-degrading bacteria Bacillus editors das M-1 of the present invention is adhered and fixed. Then, batch processing was performed for 3 days per cycle. The inside of the treatment tower was kept aerobically by aeration from the diffuser, and the discharge flow rate per cycle was 80% of the liquid in the treatment tank. A considerable portion of EDTA in the solution after the treatment was decomposed, and the COD was 20 ppm.
Similarly, when Bacillus editor Vidas M-2 and Mesophylobacter editor Vidas M-3 were used, the CODs were 35 ppm and 24 ppm, respectively.
Thus, by the method according to the present invention, decomposition of EDTA in various waste liquids can be achieved by combining with pretreatment for removing components other than EDTA.
[0054]
Example 6
Treatment of EDTA in photographic processing waste liquid (10-fold diluted liquid of silver recovery liquid and developer liquid)
Silver recovery waste liquid (color photo processing)CN-16Fixing solution,CN-16QA mixture of bleaching solution and fixing solution,CP-20For bleach fixer,CP-23Bleach-fixing solution and black-and-white photographic processing fixing solutionFuji F,GR-F1Waste liquid and water mixed at a ratio of 4, 1, 3, 2, 7, 3, 2 respectively, and then silver recovery processing) and developer waste liquid (color photographic processing)CN-16,CN-16Q,CP-20,CP-23Each color developer and black and white photographic processing developerRD3,GR-D1The waste liquid and water were mixed at a ratio of 4, 1, 3, 2, 7, 3, 2 respectively) in a volume ratio of 1: 1. This solution had a high inorganic salt concentration of 12% and was not suitable for ordinary activated sludge treatment, so it was diluted 10 times with tap water. To this solution, phosphorus was added in the form of dipotassium monohydrogen phosphate corresponding to about 2% of the COD value (about 4700 ppm). Furthermore, 10 ppm and 2 ppm of calcium ion and magnesium ion were added, respectively. The pH of the waste liquid thus prepared was 8.5.
Each of the above-described symbols with an underline is a trade name of a processing solution of Fuji Photo Film Co., Ltd.
[0055]
The waste liquid prepared earlier was subjected to biological treatment by the following steps.
Activated sludge treatment: First, this waste liquid was continuously treated with activated sludge containing sulfur oxidizing bacteria (MLSS 4500 ppm). As the activated sludge containing sulfur-oxidizing bacteria, one that was acclimatized by continuously giving a silver recovery system waste liquid 10-fold diluted solution (COD of about 4500 ppm) for 1 month with a residence time of 2 days was used. The residence time was 2 days.
The sulfuric acid produced was neutralized with a 10% aqueous sodium hydroxide solution, and the liquid in the aeration tank was kept so as not to have a pH of 6.6 or lower. A pH controller (Tokyo Rika FC-10 type) was used for pH adjustment.
[0056]
By this treatment, a liquid having a COD of 830 ppm was obtained. The processing temperature is room temperature, and the same applies to the following examples.
Nitrification: Ammonium ions (about 1000 ppm) in the waste liquid that had undergone the above-described steps were converted into nitrate ions using a nitrification tank using a string carrier (TBR Co., Ltd. Biocode) as a fixed bed of nitrifying bacteria. Nitrification was carried out by batch processing for one cycle and two days while adjusting the pH of the nitrification tank to about 7.5. The discharge rate of the treatment liquid from the treatment tank per cycle was 70% of the total amount.
Anaerobic treatment: The nitrification liquid obtained in the above-mentioned process was treated by a batch treatment of 4 cycles per cycle using an anaerobic fluidized bed using granular activated carbon (Toyo Calgon Co., Ltd. activated carbon F400) as a carrier. The discharge flow rate for each cycle of the treatment liquid from the treatment tank was 80% of the total amount. The COD of the treatment liquid was about 200 ppm, and as a result of analysis by ion chromatography, most of the organic components contained were EDTA.
[0057]
EDTA-decomposing bacteria treatment: Porous ceramic carrier (Tomei Jitsugyo Co., Ltd. CB) in which the EDTA-decomposing bacteria Bacillus editor Vidas M-1 of the present invention is adhered and fixed to the solution obtained in this way as a main component. The filter medium was circulated through a treatment tower filled with 60 vol / vol% of the treatment tower volume, and was treated in a batch treatment for 2.5 days per cycle. Air was constantly sent from the air diffuser provided at the bottom of the processing tower to keep the inside of the processing tower aerobic.
The total discharge rate of the treatment liquid from the treatment tank per cycle was 80%. The EDTA in the solution was almost decomposed by the treatment using the EDTA-degrading bacteria, and the COD after the treatment was 12 ppm. A similar experiment was performed on Bacillus editor Vidas M-2 and Mesophylobacter editor Vidas M-3. The COD after the treatment was 18 ppm and 11 ppm, respectively.
[0058]
Denitrification: nitrate ions (NO in the liquid obtained by the above treatment)₃-N as 770 ppm) was passed through a fixed-bed biological denitrification tower packed with anthracite as a carrier to effect denitrification. Methanol as TOC as an organic substance necessary for denitrification 1850 ppm (TOC / NO₃-N≈2.4 / 1). The liquid after the denitrification treatment was kept aerobically and passed through a biological filtration tower to remove remaining organic substances. The residence time was 12 hours and 4 hours in each of the denitrification tower and aerobic organism filtration. The resulting liquid had a COD of 10 ppm.
Iron removal: A 10% aqueous solution of sodium hydroxide was added to the solution obtained in the above step to adjust the pH to 8, followed by stirring for 15 minutes. A flocculant (Dainippon Ink Co., Ltd., Leulock A-500) was added and stirred for 30 minutes, and the resulting red precipitate was removed by filtration. The liquid obtained had a COD of 9 ppm.
[0059]
Example 7
Treatment of Example 6 in which EDTA-degrading bacteria (Bacillus editor Vidas M-1) are comprehensively immobilized
An acrylamide gel pellet in which EDTA-degrading bacteria (Bacillus editor Vidas M-1) were comprehensively immobilized instead of porous ceramics was used as a carrier on which EDTA-degrading bacteria were immobilized in the EDTA-degrading bacteria treatment step of Example 6. The acrylamide gel was prepared according to the method described in pages 196 to 199 of “Wastewater treatment by microorganism immobilization method” edited by Ryuichi Sudo (Industrial Water Research Committee). The acrylamide gel formed into a cube of about 3 mm per piece was used by adding about 10% of the volume of the aeration tank and allowing it to float and flow in the aeration tank. The treatment method was a batch type treatment for 2 days per cycle, and the discharge rate of the treatment liquid from the treatment tank per cycle was 80% of the total amount.
By this treatment, most of the EDTA in the liquid was decomposed, and the COD after the treatment was 11 ppm. Subsequent denitrification and iron removal were carried out in the same manner as in Example 6. As a result, the COD after each treatment was 9 ppm and 9 ppm, respectively.
Further, when Bacillus editor Vidas M-1 was replaced with Bacillus editor Vidas M-2 and Mesophylobacter editor Vidas M-3, the same results were obtained.
[0060]
Example 8
Treatment of Example 6 using activated carbon as carrier to which EDTA-degrading bacteria (Bacillus editor Vidas M-1) adhere
A granular activated carbon (Toyo Calgon Co., Ltd. activated carbon F400) was used instead of porous ceramics as a carrier on which an EDTA-degrading bacterium (Bacillus editor Vidas M-1) was adhered and immobilized in the EDTA-degrading bacterium treatment step of Example 6, and a treatment tower volume of 60 vol. The treatment was performed under the same conditions except that the treatment time was changed using / vol%.
As a result of performing batch processing in one day per cycle, EDTA in the liquid was almost decomposed and the COD after the treatment was 4 ppm.
Subsequent denitrification and iron removal were carried out in the same manner as in Example 6. As a result, the COD after each treatment was 3 ppm and 3 ppm, respectively.
The results of Examples 6, 7, and 8 are collectively shown in Table-5.
[0061]

In addition, an experiment was performed by replacing Bacillus editor Vidas M-1 with Bacillus editor Vidas M-2 and Mesophyllobacter editor Vidas M-3, and similar results were obtained.
As can be seen from the results of Examples 6, 7, and 8 shown in Table-5, various kinds of EDTA-decomposing bacteria can be used as a fixing carrier and a fixing method.
According to the method of the present invention, EDTA can be decomposed in a short time after the photographic processing waste liquid is biologically processed.
[0062]
Example 9
Treatment of EDTA in silver recovery waste liquid (suspension MF membrane filtration method)
The silver recovery system waste liquid used in Example 6 was diluted 8 times with water. Phosphorus, calcium ions, and magnesium ions were added to this solution (COD 5800 ppm) in the same proportions as in Example 6, and then biological treatment was performed using activated sludge containing sulfur-oxidizing bacteria as in Example 6. The COD after the treatment was 800 ppm. Most of the organic components remaining in the liquid were EDTA and PDTA.
Treatment with EDTA-degrading bacteria: The solution obtained by the above-mentioned treatment was treated with the EDTA-degrading bacteria Bacillus editor Vidas M-1 of the present invention suspended in the liquid. Solid-liquid separation between the EDTA-degrading bacterium and the treatment liquid was performed using an MF membrane (Mitsubishi Rayon Co., Ltd. Sterapore STNM424). The hollow fiber unit made of this MF membrane was submerged in an aeration tank, and a clear treatment liquid was obtained by performing loose suction with a connected pump. The MLSS (activated sludge suspension) of the suspension was about 7500 ppm. As a result of continuous treatment by HRT (hydraulic residence time) for 3 days, a considerable part of EDTA and PDTA in the liquid was decomposed, and the COD after the treatment was 30 ppm.
[0063]
When a sedimentation tank was used for solid-liquid separation from the suspension, MLSS was about 3000 ppm. As a result of treating the other conditions in the same manner as the MF membrane, the COD after the treatment was 80 ppm. The results are shown in Table 6 below.
Nitrification: The treatment solution obtained by the treatment using the MF membrane was diluted twice with water. Ammonium ions (about 1000 ppm) contained in this liquid were converted to nitrate ions (about 3400 ppm) by the same treatment as in the nitrification step of Example 6.
Further, denitrification and iron removal were carried out in the same manner as in Example 6. As a result, the COD after each treatment was 32 ppm and 29 ppm, respectively.
On the other hand, when the Bacillus editor Vidas M-1 used in this experiment was replaced with the Bacillus editor Vidas M-2 and Mesophylobacter editor Vidas M-3, similar results were obtained.
[0064]
[Table 9]

As can be seen from the results shown in Table-6, when the EDTA-degrading bacterium is used in a suspended state, the microbial cell concentration of the suspension is increased and the treatment performance is improved by solid-liquid separation with the MF membrane. According to the method of the present invention, after the silver recovery waste liquid discharged by photographic processing is biologically processed, the decomposition of EDTA therein can be achieved in a short time.
[0065]
Example 10
Treatment of EDTA in 2-fold diluted silver recovery waste liquid (suspension ultrafiltration method)
The silver recovery system waste liquid used in Example 6 was diluted 1.8 times with seawater (salt concentration of about 12%). To this solution (COD 25500 ppm), phosphorus in the form of dipotassium monohydrogen phosphate was added in an amount corresponding to about 1% of the COD value. The waste liquid thus prepared was subjected to biological treatment by the following steps.
Activated sludge treatment: Treated using the membrane-separated high-concentration activated sludge method described in pp. 183 to 193 of the 27th Sanitary Engineering Research Conference (1991). That is, after processing using high-concentration marine activated sludge, solid-liquid separation between the suspension and the processing liquid was performed using a UF membrane. The marine activated sludge was prepared using bacteria grown in the liquid by ventilating a 10-fold diluted silver recovery waste liquid with seawater. It processed in the state which suspended marine activated sludge in the waste liquid prepared above. The treatment was carried out in the same manner as described in the above papers, except that the pH of the suspension was adjusted so as not to be 7.5 or less with a pH controller. The MLSS of the suspension was about 37000 ppm. As a result of continuous treatment for 7 days on HRT, the COD after the treatment was 4200 ppm. Most of the organic components remaining in the liquid were EDTA and PDTA.
Treatment with EDTA-degrading bacteria: The treatment was carried out in the same manner as in Example 9 with the EDTA-degrading bacteria Bacillus editor Vidas M-1 suspended in the solution obtained by the above treatment.
The MLSS of the suspension was about 15000 ppm. As a result of continuous treatment on the 2nd day of HRT, a considerable part of EDTA and PDTA in the liquid was decomposed, and the COD after the treatment was 110 ppm.
Moreover, when it processed using Bacillus editor Vidas M-2 and Mesophyllobacter editor Vidas M-3, although the processing rate fell from M-1, in all, COD after a process was as favorable as 140 ppm or less.
As described above, the Bacillus editor Vidas M-1, the Bacillus editor Vidas M-2, and the Mesophylobacter editor Vidas M-3 of the present invention can be applied to waste liquids having a high salt concentration to save dilution water and space. The processing cost can be reduced.
Example 11
A culture solution was prepared by replacing the organic aminopolycarboxylic acid of Example 3 with EDTA · 2Na and EDTA-Mg, respectively, and salt was added to make the salt concentration 10%. These solutions were inoculated with EDTA-degrading bacteria in the same manner as in Example 3, and cultured with shaking at 27 ° C. for 10 days. The decomposition rate was determined in the same manner as in Example 1. The results are shown in Table-7.
[Table 10]

Next, when EDTA · 2Na was replaced with EDTA chelates of various metals (Ca, Cu, Zn, Pb, Mn, Ni), and the decomposition rate was determined in the same manner, all of the three types of bacteria of the present invention were 60% or more. Degradation rate is shown.
When the organic aminocarboxylic acid-degrading bacteria, which are conventionally known soil bacteria, are used, the decomposition of the organic aminocarboxylic acid Na salt or Mg salt is not observed, whereas the marine bacterium EDTA-degrading bacteria of the present invention are those It can be seen that can be efficiently decomposed.

Claims (4)

Organic aminocarboxylic acid-degrading bacteria Bacillus editabidus and Mesophilobacter editabidus that can survive in an aqueous solution having a salt concentration of 10% by weight. An organic aminocarboxylic acid-degrading bacterium Bacillus editabidus is Bacillus editabidus- M1 (Maiken Kenkyu No. 14868) or Bacillus editabidus- M2 ( Maiken Kenkyu Yone 14869), Mesophyllobacter The organic aminocarboxylic acid-degrading bacterium according to claim 1 , wherein the editor Bidas ( Mesophilobacter editabidus) is Mesophilobacter editabidus- M3 (No. 14870, manufactured by MICROKEN) . A method for treating a waste liquid containing organic aminocarboxylic acids, comprising mixing or contacting the organic aminocarboxylic acid-degrading bacterium according to claim 1 or 2 with a waste liquid containing organic aminocarboxylic acids. The marine bacterium according to claim 1 or 2, which decomposes organic aminocarboxylic acids, is mixed or contacted with a waste liquid having an inorganic salt concentration of 2% by weight or more and containing sodium and / or magnesium salts of organic aminocarboxylic acids. A method for treating a waste liquid containing organic aminocarboxylic acids.