JP3922920B2

JP3922920B2 - Biological deodorization equipment

Info

Publication number: JP3922920B2
Application number: JP2001384549A
Authority: JP
Inventors: 敏男塚本; 茂樹山下; 克之片岡; 俊博田中; 孝幸加太
Original assignee: Ebara Corp
Current assignee: Ebara Corp
Priority date: 2001-12-18
Filing date: 2001-12-18
Publication date: 2007-05-30
Anticipated expiration: 2021-12-18
Also published as: JP2003181240A

Description

【０００１】
【発明の属する技術分野】
本発明は、悪臭ガスの生物学的脱臭に係り、特に、下水処理場、し尿処理場、各種工場等から発生する臭気ガスを生物学的に脱臭するための生物脱臭装置に関する。
【０００２】
【従来の技術】
微生物を付着させた担体を充填した充填層に、臭気ガスを通気して生物学的に脱臭する充填塔式生物脱臭法は、維持管理が容易で低コストな利点が注目され、今や、下水処理場等の脱臭対策における中心的役割を担っている。このような生物脱臭装置の充填材には、軽量であること積層しても圧密しないだけの圧縮強度があること、耐久性があること、安価であることなどが要求されるため、これらの条件を満たす合成樹脂性の充填材が汎用されてきた。しかし、圧縮強度が大きい合成樹脂の多くは、疎水性が強く、吸水性が低いため、微生物の付着性や保水性が悪く、その結果、悪臭物質の高効率除去を実現することは困難であった。
【０００３】
一方、悪臭物質の高効率除去が可能な充填材として、天然繊維状有機物（ビート）や、吸水性合成繊維等が従来から用いられている。ビートは、比表面積、空隙率、保水性、親水性、微生物付着性の面において、生物脱臭用充填材として優れた特性を有する反面、材質の強度に欠けると共に、生物分解性があるため長期間原形を維持することが困難である欠点があった。また、吸水性合成繊維は、重量、比表面積、空隙率、保水性、親水性、微生物付着性の面において優れた特性を有するばかりでなく、耐生物分解性や耐薬品性のある優れた素材である。しかし、ビートと同様に、材質自体の強度に欠けると共に、吸水すると膨潤・軟化するため、充填層が圧密化し、圧力損失の上昇が生じ易い問題があった。
【０００４】
このような材質強度上の欠点を補うために、少なくとも５０重量％以上の耐水性合成繊維を含有する繊維とバインダーよりなる板状繊維集合体に、水溶性ポリマーを架橋剤で架橋して非水溶性化したポリマーを含有する保水剤を塗布してなる脱臭装置用板状繊維集合体によって、充填層の圧密化、圧力損失の上昇を防止できると共に、優れた微生物付着性能を実現できることが知られている。しかし、このような繊維集合体は、三次元方向に強度を持たせることが難しいため、鉛直方向には圧密し難い配置をとっても、水平方向に充填層が圧密、変形し、ガスの短絡を生じる問題があった。また、三次元的に強度を持たせるために、繊維密度を高めると、余剰汚泥の排出や、スムースなガスの流れ及び散水された水の排出を実現することが困難になる問題があった。さらに、このような樹脂成型体は、加工が煩雑なため、高価であるといった問題があった。
【０００５】
【発明が解決しようとする課題】
本発明は、上記の問題点を解決し、圧縮強度の大きい合成樹脂製充填材（以下、保形性充填材）を用いた場合と同等の保形性及び良好な通気性を有し、かつ、吸水性合成樹脂製充填材（以下、吸水性充填材）を用いた場合と同等の保水性、微生物保持性能を有する充填層を用いて、効率よく脱臭することが可能な生物脱臭装置を提供することを課題とする。
【０００６】
【課題を解決するための手段】
上記課題を解決するために、本発明では、充填材を充填した充填層に、悪臭ガスを通気して脱臭を行う生物脱臭装置において、該充填層には、粒状の吸水性合成樹脂製充填材と、該吸水性合成樹脂製充填材よりも圧縮強度が大きい粒状の保形性充填材とが混合して充填されていることを特徴とする生物脱臭装置としたものである。
前記生物脱臭装置において、吸水性合成樹脂製充填材と、該吸水性合成樹脂製充填材よりも圧縮強度が大きい保形性充填材との混合割合は、吸水性合成樹脂製充填材が１体積に対して、該吸水性合成樹脂製充填材よりも圧縮強度が大きい充填材０．１〜１０体積とするのがよい。
【０００７】
【発明の実施の形態】
本発明者らは、生物脱臭用充填材として、良好な通気性を有する保形性充填材と、保水性・微生物保持性能を有する吸水性充填材とを混合して充填した充填層を形成したことによって、双方の充填材の利点が活かされると共に、双方の充填材の問題点が解消され、このような充填層を用いた生物脱臭装置が、長期間にわたって良好な通気性、悪臭物質除去性能を発揮できることを見出し、本発明を完成した。
本発明は、良好な通気性を有する反面、保水性・微生物保持性能に劣る保形性充填材と、保水性・微生物保持性能に優れる反面、保形性・通気性に劣る吸水性充填材とを混合して充填することによって、双方の充填材の利点を生かしつつ欠点を補うことが目的である。
【０００８】
通常、このような混合充填では、双方の充填材のもつ欠点はある程度相殺されるものの、利点も相殺されてしまうものであるが、本発明者らは、種々の検討の結果、保形性充填材と吸水性充填材とを混合して充填すると、次の機構によって、一種類の充填材を単独で充填する場合に生ずる欠点のみが解消され、利点はそのまま活かされることを見出した。
（１）保形性・通気性：保形性充填材が混合充填されることによって、圧縮強度の高い骨格構造を形成する。この骨格の間に吸水性充填材が存在する形態をとることから、吸水性充填材自体が吸水して膨潤・軟化・重量化しても、圧縮強度の高い骨格構造に保護されるため、充填層が圧密することは無く、保形性充填材を単独で充填した場合と同等に充填層が保形され、良好な通気性が維持できる。
【０００９】
（２）悪臭物質除去性能：保形性充填材を単独で充填した場合は、材質が疎水性・非吸水性であることが多いために、散水された水が偏流して充填層全体に行き渡らない。その結果として、悪臭物質除去に寄与することができない部分が発生するため、高い悪臭物質除去性能を得ることは難しい。一方、吸水性充填材を単体で充填した場合は、充填層全体に散水された水が行き渡り、かつ、大量の微生物を保持できるのであるが、徐々に充填層が圧密することにより、通気性が悪くなるばかりでなく、有効比表面積の減少や、水やガスの偏流が生じるため、長期間にわたって高い悪臭物質除去性能を維持することは難しい。これらに対して、本発明では、前記（１）記載のとおり、保水性及び微生物保持性能の高い吸水性充填材を圧密させることなく、充填層全体を悪臭物質除去に有効に利用できる。その結果として、吸水性充填材を単独で充填する場合よりも、充填層全体に保持される微生物を保持量は少ないにもかかわらず、高い悪臭物質除去性能を発揮できるのである。
【００１０】
本発明の保形性充填材と吸水性充填材の混合方法は、上記のような機構を実現できる方法であれば何ら制限はないが、粒状の充填材同士をランダムに混合する方法が、容易であり、また既存の安価な充填材を活用できる点で現実的である。ただし、保形性を持たせる意味で、保形性充填材同士が少なくとも一個所で接触していることが望ましく、かつ、散水された水を偏流させない意味で、吸水性充填材同士が少なくとも一箇所で接触し、吸水性充填材を介して充填層全体に液絡を形成していることが望ましいため、双方の充填材が偏ることなく均一に混合されることが必要である。
保形性充填材と吸水性充填材の混合割合は、保形性充填材の割合が低過ぎると、充填層の保形性が悪くなり、逆に、吸水性充填材の割合が低過ぎると、微生物付着性が悪くなると共に、散水された水が偏流するため悪臭物質除去性能が低下することから、吸水性充填材１体積に対して保形性合成樹脂０．１〜１０体積が好ましく、さらに好ましくは、吸水性充填材１体積に対して、保形性充填材０．５〜５体積である。
【００１１】
保形性充填材と吸水性充填材の粒径比は、保形性充填材の粒径が吸水性充填材の粒径に比して小さ過ぎると、保形性が悪くなり、逆に、吸水性充填材の粒径が保形性充填材の粒径に比して小さ過ぎると、保形性充填材の形成した骨格構造の空隙を吸水性充填材が完全に埋めてしまい充填層が閉塞するため、吸水性充填材１に対して保形性充填材０．１〜１０が好ましく、吸水性充填材１に対して、保形性充填材０．５〜５がさらに好ましい。
本発明の保形性充填材（乾燥状態）は、軽量、保形性、耐久性のある材質であれば、親水性、微生物付着性、吸水性等に制限はなく、具体的には、かさ比重が０．８以下のものであり、かつ、圧縮強度（２５％変形）が、１００ＫＰａ以上のものが望ましい。材質の例としては、ポリウレタン、ポリプロピレン、ポリエチレン、ポリ塩化ビニル、ポリ塩化ビニリデン、ポリエチレンテレフタレート、ポリビニルホルマール等が挙げられる。充填材の形状は、粉粒体、繊維集合体、二次元的形状、三次元的形状のいずれであってもよく、例えば、粒状、ペレット状、球状、他面体（サイコロ状）、ハニカム状、シート状、ブロック状、短冊状、中空円筒状、サドル状、スポンジ状などの形状を有しているものが挙げられる。充填材のサイズ１は特に限定されず、通常、平均径として、１〜５０ｍｍ、好ましくは３〜４０ｍｍ、さらに好ましくは５〜２０ｍｍである。
【００１２】
本発明の吸水性充填材は、軽量、耐久性、親水性で微生物付着性が良好であり、かつ、吸水性の高い材質であれば保形性に制限はなく、具体的には、かさ比重（乾燥状態）が０．８以下のものであり、かつ、公定水分率２％以上のものが望ましい。ナイロン、ビニロン、ビスコースレーヨン、キュプラ、アセテート、アクリル、親水性ポリウレタン等が挙げられる。充填材の形状は、粉粒体、繊維集合体、二次元的形状、三次元的形状のいずれであってもよく、例えば、粒状、ペレット状、球状、他面体（サイコロ状）、ハニカム状、シート状、ブロック状、短冊状、中空円筒状、サドル状、スポンジ状などの形状を有しているものが挙げられる。充填材のサイズは特に限定されず、通常、平均径として、１〜５０ｍｍ、好ましくは３〜４０ｍｍ、さらに好ましくは５〜２０ｍｍである。
本発明では、保形性充填材が、主に充填層の保形と通気性確保の役割を担い、吸水性充填材が主に微生物付着担体及び散水された水の偏流を防止する役割を担うのであるが、保形性充填材であっても比較的親水性、吸水性の高いもの、また、吸水性充填材であっても比較的保形性の高いもの同士を混合充填するのがさらに好適である。
【００１３】
以下に、本発明を図面を参照して詳細に説明する。
図１は、本発明の生物脱臭装置の一例を示す断面構成図である。
図１において、充填塔３は、保形性充填材５及び吸水性充填材６を充填した充填層４と、充填層４に散水用水７を散水するための散水部８と、散水した後の水を排水するための配水管９を備える。
散水部８から充填層４に対して散水すると共に、臭気ガス１を充填塔３に導入し、臭気ガス１中に含まれる悪臭物質を除去し、処理ガス２として排出する。
【００１４】
【実施例】
以下、本発明を実施例により具体的に説明する。
実施例１
保形性充填材としてポリプロピレン粒状体を、吸水性充填材として親水性ポリウレタンフォームを、容積比１：１で十分に混合して、図１に示す生物脱臭装置の充填層に充填し、下水処理施設の汚泥処理工程から発生する臭気を原ガスとして、脱臭処理した。運転条件は次のとおりである。
原ガス性状硫化水素濃度：３２ｐｐｍ
メチルメルカプタン濃度：２．０ｐｐｍ
硫化メチル濃度：０．２１ｐｐｍ
二硫化メチル濃度：０．０１０ｐｐｍ
温度：２４℃
【００１５】
空塔速度：３６０ｈｒ^-1
空塔線速度：０．２ｍ／ｓｅｃ
散水頻度：１時間に２分間
散水時の液ガス比（単位処理ガス量あたりの散水量）：３Ｌ／ｍ³
脱臭処理開始から３ヶ月経過後、処理ガスの悪臭物質濃度は、硫化水素０．００１ｐｐｍ以下、メチルメルカプタン０．００１ｐｐｍ以下、硫化メチル０．００１ｐｐｍ以下、二硫化メチル０．００１ｐｐｍ以下となった。以後、長期にわたって安定した悪臭物質除去性能を示し、充填層の圧力損失も１１０Ｐａ程度の低い値で安定した。脱臭処理開始から３ヶ月経過後の脱臭成績を表１に示す。
【００１６】
実施例２
充填層に、保形性充填材として疎水性ポリウレタンフォームを、吸水性充填材として親水性ポリウレタンフォームを、容積比１：１で十分に混合したものを充填した以外、実施例１と同じ条件で脱臭処理した。
脱臭処理開始から３ヶ月経過後、処理ガスの悪臭物質濃度は、硫化水素０．００１ｐｐｍ以下、メチルメルカプタン０．００１ｐｐｍ以下、硫化メチル０．００１ｐｐｍ以下、二硫化メチル０．００１ｐｐｍ以下となった。以後、長期にわたって安定した悪臭物質除去性能を示し、充填層の圧力損失も９５Ｐａ程度の低い値で安定した。脱臭処理開始から３ヶ月経過後の脱臭成績を表１に示す。
【００１７】
実施例３
充填層に、保形性充填材としてポリビニルホルマールの高ホルマール化物を、吸水性充填材としてポリビニルホルマールの低ホルマール化物を、容積比１：１で十分に混合したものを充填した以外、実施例１と同じ条件で脱臭処理した。
脱臭処理開始から３ヶ月経過後、処理ガスの悪臭物質濃度は、硫化水素０．００１ｐｐｍ以下、メチルメルカプタン０．００１ｐｐｍ以下、硫化メチル０．００１ｐｐｍ以下、二硫化メチル０．００１ｐｐｍ以下となった。以後、長期にわたって安定した悪臭物質除去性能を示し、充填層の圧力損失も１４５Ｐａ程度の低い値で安定した。脱臭処理開始から３ヶ月経過後の脱臭成績を表１に示す。
【００１８】
比較例１
充填層に、ポリプロピレン粒状体を単独で充填した以外、実施例１と同じ条件で脱臭処理した。
脱臭処理開始から３ヶ月経過後、処理ガスの悪臭物質濃度は、硫化水素０．００１ｐｐｍ以下、メチルメルカプタン０．０２１ｐｐｍ、硫化メチル０．１７ｐｐｍ、二硫化メチル０．３３ｐｐｍであり、実施例１に比べて悪臭物質除去性能は低かった。以後、長期にわたって脱臭運転を継続しても、実施例１の悪臭物質除去性能には到達しなかった。充填層の圧力損失は、長期間９０Ｐａ程度の低
い値を維持した。脱臭処理開始から３ヶ月経過後の脱臭成績を表１に示す。
【００１９】
比較例２
充填材に、親水性ポリウレタンフォームを単独で充填した以外、実施例１と同じ条件で脱臭処理した。
脱臭処理開始から１ヶ月経過後、処理ガスの悪臭物質濃度は、硫化水素０．００１ｐｐｍ以下、メチルメルカプタン０、００１ｐｐｍ以下、硫化メチル０．００１ｐｐｍ以下、二硫化メチル０．００１ｐｐｍ以下であり、実施例１と同等の悪臭物質除去性能を示した。しかし、充填層の圧密が顕著であり、圧密に伴って充填層の圧力損失は徐々に上昇した。圧力損失は、１ヶ月日で８００Ｐａ、３ヶ月日で２０００Ｐａを示し通気量が低下した。なお、この時点では、散水された水が充填層内で偏流しており、処理ガスの悪臭物質濃度は、硫化水素０．１２ｐｐｍ、メチルメルカプタン０．１８ｐｐｍ、硫化メチル０．１８ｐｐｍ、二硫化メチル０．１２ｐｐｍであり、脱臭処理開始から１ヶ月経過時に比べて悪臭物質除去性能は低下した。脱臭処理開始から３ヶ月経過後の脱臭成績を表１に示す。
【００２０】
比較例３
充填層に、疎水性ポリウレタンフォームを単独で充填した以外、実施例１と同じ条件で脱臭処理した。
脱臭処理開始から３ヶ月経過後、処理ガスの悪臭物質濃度は、硫化水素０．０９ｐｐｍ、メチルメルカプタン０．２１ｐｐｍ、硫化メチル０．１６ｐｐｍ、二硫化メチル０．２３ｐｐｍであり、実施例１に比べて悪臭物質除去性能は低かった。以後、長期にわたって脱臭運転を継続しても実施例１の悪臭物質除去性能には到達しなかった。充填層の圧力損失は、長期間４０Ｐａ程度の低い値を維持した。脱臭処理開始から３ヶ月経過後の脱臭成績を表１に示す。
【００２１】
比較例４
充填層に、ポリビニルホルマールの高ホルマール化物を単独で充填した以外、実施例１と同じ条件で脱臭処理した。
脱臭処理開始から３ヶ月経過後、処理ガスの悪臭物質濃度は、硫化水素０．０３ｐｐｍ、メチルメルカプタン０．１５ｐｐｍ、硫化メチル０．１１ｐｐｍ、二硫化メチル０．０８ｐｐｍであり、実施例１に比べて悪臭物質除去性能は低かった。以後、長期にわたって脱臭運転を継続しても実施例１の悪臭物質除去性能には到達しなかった。充填層の圧力損失は、長期間１１０Ｐａ程度の低い値を維持した。脱臭処理開始から３ヶ月経過後の脱臭成績を表１に示す。
【００２２】
比較例５
充填材に、ポリビニルホルマールの低ホルマール化物を単独で充填した以外、実施例１と同じ条件で脱臭処理した。
脱臭処理開始から１ヶ月経過後、処理ガスの悪臭物質濃度は、硫化水素０．００１ｐｐｍ以下、メチルメルカプタン０．００１ｐｐｍ以下、硫化メチル０．００１ｐｐｍ以下、二硫化メチル０．００１ｐｐｍ以下であり、実施例１と同等の悪臭物質除去性能を示した。しかし、充填層の圧密が顕著であり、圧密に伴って充填層の圧力損失は徐々に上昇した。圧力損失は、１ヶ月日で５５０Ｐａ、３ヶ月目で１４０００Ｐａを示し通気量が低下した。なお、この時点では、散水された水が充填層内で偏流しており、処理ガスの悪臭物質濃度は、硫化水素０．００１ｐｐｍ以下、メチルメルカプタン０．００８ｐｐｍ、硫化メチル０．０１４ｐｐｍ、二硫化メチル０．０６２ｐｐｍであり、脱臭処理開始から１ヶ月経過時に比べて悪臭物質除去性能は低下した。脱臭処理開始から３ヶ月経過後の脱臭成績を表１に示す。
【００２３】
【表１】

【００２４】
【発明の効果】
本発明では、充填材を充填した充填層に、悪臭ガスを通気して脱臭を行う生物脱臭装置において、該充填層に、吸水性合成樹脂製充填材と、該吸水性合成樹脂製充填材よりも圧縮強度が大きい充填材とを混合して充填することで、充填層の圧力損失の上昇をまねくことなく、高い悪臭物質除去性能を得ることができる。
【図面の簡単な説明】
【図１】本発明の生物脱臭装置の一例を示す断面構成図。
【符号の説明】
１：臭気ガス、２：処理ガス、３：充填塔、４：充填層、５：保形性充填材、６：吸水性充填材、７：散水用水、８：散水部、９：配水管[0001]
BACKGROUND OF THE INVENTION
The present invention relates to biological deodorization of malodorous gas, and more particularly to a biological deodorization apparatus for biologically deodorizing odorous gas generated from sewage treatment plants, human waste treatment plants, various factories and the like.
[0002]
[Prior art]
The packed tower type biological deodorization method, in which odorous gas is passed through a packed bed filled with a carrier on which microorganisms are attached, is biologically deodorized. Its advantages are easy to maintain and low cost. It plays a central role in deodorizing countermeasures for places. Such a biodeodorizing device is required to have a lightweight, compressive strength that does not compress even when laminated, durability, and low cost. Synthetic resin fillers satisfying the requirements have been widely used. However, many synthetic resins with high compressive strength have strong hydrophobicity and low water absorption, so that adhesion of microorganisms and water retention are poor, and as a result, it is difficult to achieve high-efficiency removal of malodorous substances. It was.
[0003]
On the other hand, natural fibrous organic substances (beets), water-absorbing synthetic fibers, and the like have been conventionally used as fillers capable of removing malodorous substances with high efficiency. Beet has excellent properties as a biodeodorant filler in terms of specific surface area, porosity, water retention, hydrophilicity, and microbial adhesion, but it lacks the strength of the material and is biodegradable for a long time. There was a drawback that it was difficult to maintain the original shape. In addition, water-absorbing synthetic fibers not only have excellent properties in terms of weight, specific surface area, porosity, water retention, hydrophilicity, and microbial adhesion, but also are excellent materials with biodegradation resistance and chemical resistance. It is. However, like the beet, the material itself lacks strength, and when it absorbs water, it swells and softens. Therefore, there is a problem that the packed layer is consolidated and pressure loss is likely to increase.
[0004]
In order to make up for such defects in material strength, a water-soluble polymer is cross-linked with a cross-linking agent to a plate-like fiber assembly composed of a fiber containing at least 50% by weight of a water-resistant synthetic fiber and a binder, thereby making it non-water-soluble. It is known that a plate-like fiber assembly for a deodorization device formed by applying a water retaining agent containing a polymerized polymer can prevent consolidation of the packed bed and increase in pressure loss, and can realize excellent microbial adhesion performance. ing. However, since it is difficult to give such a fiber assembly strength in the three-dimensional direction, even if it is difficult to consolidate in the vertical direction, the packed bed is consolidated and deformed in the horizontal direction, causing a gas short circuit. There was a problem. Further, when the fiber density is increased in order to give strength in three dimensions, there is a problem that it becomes difficult to realize discharge of excess sludge, smooth gas flow, and sprinkled water. Further, such a resin molded body has a problem that it is expensive due to complicated processing.
[0005]
[Problems to be solved by the invention]
The present invention solves the above-mentioned problems, has shape retention and good air permeability equivalent to the case where a synthetic resin filler (hereinafter referred to as shape retention filler) having a high compressive strength is used, and A biological deodorization device that can efficiently deodorize using a packed bed having water retention and microbial retention performance equivalent to the case of using a water absorbent synthetic resin filler (hereinafter referred to as a water absorbent filler). The task is to do.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, in the present invention, in a biological deodorization apparatus that performs deodorization by aeration of malodorous gas through a packed bed filled with a filler, the packed bed is made of a granular water-absorbing synthetic resin filler. And a granular shape-retaining filler having a compressive strength larger than that of the water-absorbent synthetic resin filler.
In the biological deodorization apparatus, the mixing ratio of the water absorbent synthetic resin filler and the shape-retaining filler having a compressive strength larger than that of the water absorbent synthetic resin filler is 1 volume of the water absorbent synthetic resin filler. On the other hand, it is good to set it as 0.1-10 volume of fillers whose compressive strength is larger than this water absorbent synthetic resin filler.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The present inventors formed a packed bed filled with a mixture of a shape-retaining filler having good air permeability and a water-absorbing filler having water retention / microbe retention performance as a filler for biodeodorization. As a result, the advantages of both fillers can be utilized, the problems of both fillers can be solved, and the biological deodorization device using such a packed bed has good air permeability and bad odor substance removal performance over a long period of time. The present invention has been completed.
While the present invention has good air permeability, the shape-retaining filler is inferior in water retention / microorganism retention performance, and the water-absorbent filler is inferior in water retention / microorganism retention performance but inferior in shape retention / breathability. The purpose of this is to make up for the disadvantages while taking advantage of both fillers.
[0008]
Usually, in such mixed filling, the disadvantages of both fillers are offset to some extent, but also the advantages are offset. It has been found that when the material and the water-absorbing filler are mixed and filled, the following mechanism eliminates only the drawbacks caused when filling one kind of filler alone, and the advantage is utilized as it is.
(1) Shape retention / breathability: A skeletal structure with high compressive strength is formed by mixing and filling shape retention fillers. Since the water-absorbing filler is present between the skeletons, even if the water-absorbing filler itself absorbs water and swells, softens, and weights, it is protected by a skeleton structure with high compressive strength. Is not consolidated, and the packed layer is retained in the same manner as when the shape-retaining filler is filled alone, so that good air permeability can be maintained.
[0009]
(2) Malodorous substance removal performance: When the shape-retaining filler is filled alone, the material is often hydrophobic and non-water-absorbing, so the sprinkled water drifts and spreads throughout the packed bed. Absent. As a result, portions that cannot contribute to the removal of malodorous substances are generated, and it is difficult to obtain high malodorous substance removal performance. On the other hand, when the water-absorbing filler is filled as a single substance, the water sprayed over the entire packed bed spreads and can retain a large amount of microorganisms. Not only does it worsen, but it also makes it difficult to maintain high odor substance removal performance over a long period of time because it reduces the effective specific surface area and causes drift of water and gas. In contrast, in the present invention, as described in (1) above, the entire packed bed can be effectively used for removing malodorous substances without compacting a water-absorbing filler having high water retention and microorganism retention performance. As a result, higher malodorous substance removal performance can be exhibited, although the amount of microorganisms retained in the entire packed bed is smaller than when the water-absorbing filler is filled alone.
[0010]
The method for mixing the shape-retaining filler and the water-absorbing filler of the present invention is not limited as long as it can realize the mechanism as described above, but the method of randomly mixing the granular fillers is easy. In addition, it is realistic in that existing inexpensive fillers can be used. However, it is desirable that the shape-retaining fillers are in contact with each other at least at one point in order to provide shape retention, and at least one of the water-absorbing fillers does not cause the scattered water to drift. Since it is desirable to make contact with each other and form a liquid junction in the entire packed bed through the water-absorbing filler, it is necessary that both fillers are uniformly mixed without being biased.
If the proportion of the shape-retaining filler and the water-absorbent filler is too low, the shape-retaining property of the packed layer becomes worse if the proportion of the shape-retaining filler is too low, and conversely if the proportion of the water-absorbent filler is too low. In addition, the adhesion of microorganisms is worsened, and the odorous substance removal performance is reduced because the sprinkled water drifts. Therefore, the shape-retaining synthetic resin is preferably 0.1 to 10 volumes with respect to 1 volume of the water-absorbing filler, More preferably, the shape-retaining filler is 0.5 to 5 volumes with respect to 1 volume of the water-absorbing filler.
[0011]
If the particle size ratio of the shape-retaining filler and the water-absorbent filler is too small compared to the particle size of the water-absorbent filler, the shape-retaining property becomes worse. If the water-absorbing filler particle size is too small compared to the shape-retaining filler particle size, the water-absorbing filler completely fills the voids of the skeletal structure formed by the shape-retaining filler material. For blockage, the shape-retaining filler 0.1 to 10 is preferable for the water-absorbing filler 1, and the shape-retaining filler 0.5 to 5 is more preferable for the water-absorbing filler 1.
The shape-retaining filler (dried state) of the present invention is not limited in terms of hydrophilicity, microbial adhesion, water absorption, etc., as long as it is a lightweight, shape-retaining and durable material. It is desirable that the specific gravity is 0.8 or less and the compressive strength (25% deformation) is 100 KPa or more. Examples of the material include polyurethane, polypropylene, polyethylene, polyvinyl chloride, polyvinylidene chloride, polyethylene terephthalate, and polyvinyl formal. The shape of the filler may be any of powder, fiber aggregate, two-dimensional shape, and three-dimensional shape. For example, granular, pellet-like, spherical, other-faced body (dice-like), honeycomb-like, Examples include a sheet shape, a block shape, a strip shape, a hollow cylindrical shape, a saddle shape, and a sponge shape. The size 1 of the filler is not particularly limited, and is usually 1 to 50 mm, preferably 3 to 40 mm, and more preferably 5 to 20 mm as an average diameter.
[0012]
The water-absorbing filler of the present invention is lightweight, durable, hydrophilic, has good adhesion to microorganisms, and has a high water-absorbing material. It is desirable that the (dried state) is 0.8 or less and the official moisture content is 2% or more. Examples include nylon, vinylon, viscose rayon, cupra, acetate, acrylic, and hydrophilic polyurethane. The shape of the filler may be any of powder, fiber aggregate, two-dimensional shape, and three-dimensional shape. For example, granular, pellet-like, spherical, other-faced body (dice-like), honeycomb-like, Examples include a sheet shape, a block shape, a strip shape, a hollow cylindrical shape, a saddle shape, and a sponge shape. The size of a filler is not specifically limited, Usually, it is 1-50 mm as an average diameter, Preferably it is 3-40 mm, More preferably, it is 5-20 mm.
In the present invention, the shape-retaining filler mainly plays the role of retaining the shape of the packed bed and ensuring air permeability, and the water-absorbing filler mainly plays the role of preventing the drift of the microorganism-adhering carrier and the sprinkled water. However, even a shape-retaining filler is relatively hydrophilic and has a high water-absorbing property, and even a water-absorbing filler having a relatively high shape-retaining property is mixed and filled. Is preferred.
[0013]
Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional configuration diagram showing an example of the biological deodorization apparatus of the present invention.
In FIG. 1, the packed tower 3 includes a packed bed 4 filled with a shape-retaining filler 5 and a water-absorbing filler 6, a sprinkler 8 for sprinkling water 7 for spraying the packed bed 4, A water distribution pipe 9 for draining water is provided.
Water is sprayed from the water sprinkling part 8 to the packed bed 4, the odor gas 1 is introduced into the packed tower 3, the malodorous substances contained in the odor gas 1 are removed, and the processed gas 2 is discharged.
[0014]
【Example】
Hereinafter, the present invention will be specifically described by way of examples.
Example 1
A polypropylene granule as a shape-retaining filler and a hydrophilic polyurethane foam as a water-absorbing filler are sufficiently mixed at a volume ratio of 1: 1 and filled in the packed bed of the biological deodorization apparatus shown in FIG. Deodorization treatment was performed using the odor generated from the sludge treatment process at the facility as the raw gas. The operating conditions are as follows.
Raw gas properties Hydrogen sulfide concentration: 32ppm
Methyl mercaptan concentration: 2.0ppm
Methyl sulfide concentration: 0.21 ppm
Methyl disulfide concentration: 0.010 ppm
Temperature: 24 ° C
[0015]
Superficial velocity: 360 hr ^-1
Empty line speed: 0.2m / sec
Sprinkling frequency: Liquid gas ratio at the time of watering for 2 minutes per hour (watering amount per unit processing gas amount): 3 L / m ³
After 3 months from the start of the deodorization treatment, the malodorous substance concentration of the treatment gas became 0.001 ppm or less of hydrogen sulfide, 0.001 ppm or less of methyl mercaptan, 0.001 ppm or less of methyl sulfide, and 0.001 ppm or less of methyl disulfide. Thereafter, stable odor substance removal performance was exhibited over a long period of time, and the pressure loss of the packed bed was stabilized at a low value of about 110 Pa. Table 1 shows the deodorization results after 3 months from the start of the deodorization treatment.
[0016]
Example 2
Under the same conditions as in Example 1, except that the packed layer was filled with a hydrophobic polyurethane foam as a shape-retaining filler and a hydrophilic polyurethane foam as a water-absorbing filler, which was sufficiently mixed at a volume ratio of 1: 1. Deodorized.
After 3 months from the start of the deodorization treatment, the malodorous substance concentration of the treatment gas became 0.001 ppm or less of hydrogen sulfide, 0.001 ppm or less of methyl mercaptan, 0.001 ppm or less of methyl sulfide, and 0.001 ppm or less of methyl disulfide. After that, stable odor substance removal performance was exhibited over a long period of time, and the pressure loss of the packed bed was stabilized at a low value of about 95 Pa. Table 1 shows the deodorization results after 3 months from the start of the deodorization treatment.
[0017]
Example 3
Example 1 except that the packed layer was filled with a highly formalized product of polyvinyl formal as a shape-retaining filler and a low-formalized product of polyvinyl formal as a water-absorbing filler, sufficiently mixed at a volume ratio of 1: 1. Was deodorized under the same conditions.
After 3 months from the start of the deodorization treatment, the malodorous substance concentration of the treatment gas became 0.001 ppm or less of hydrogen sulfide, 0.001 ppm or less of methyl mercaptan, 0.001 ppm or less of methyl sulfide, and 0.001 ppm or less of methyl disulfide. Thereafter, stable odor substance removal performance was exhibited over a long period of time, and the pressure loss of the packed bed was stabilized at a low value of about 145 Pa. Table 1 shows the deodorization results after 3 months from the start of the deodorization treatment.
[0018]
Comparative Example 1
Deodorizing treatment was performed under the same conditions as in Example 1 except that the packed layer was filled with polypropylene granules alone.
After 3 months from the start of the deodorizing treatment, the malodorous substance concentration of the treatment gas is 0.001 ppm or less of hydrogen sulfide, 0.021 ppm of methyl mercaptan, 0.17 ppm of methyl sulfide, and 0.33 ppm of methyl disulfide. The bad odor removal performance was low. Thereafter, even if the deodorizing operation was continued for a long time, the malodorous substance removing performance of Example 1 was not reached. The pressure loss of the packed bed maintained a low value of about 90 Pa for a long time. Table 1 shows the deodorization results after 3 months from the start of the deodorization treatment.
[0019]
Comparative Example 2
Deodorizing treatment was performed under the same conditions as in Example 1 except that the filler was filled with hydrophilic polyurethane foam alone.
One month after the start of the deodorizing treatment, the malodorous substance concentration of the treatment gas is 0.001 ppm or less of hydrogen sulfide, 0, 001 ppm or less of methyl mercaptan, 0.001 ppm or less of methyl sulfide, 0.001 ppm or less of methyl disulfide, The malodorous substance removal performance equivalent to 1 was shown. However, the compaction of the packed bed was remarkable, and the pressure loss of the packed bed gradually increased with consolidation. The pressure loss was 800 Pa for 1 month and 2000 Pa for 3 months, and the air flow rate decreased. At this time, the sprinkled water is drifting in the packed bed, and the malodorous substance concentration of the processing gas is 0.12 ppm of hydrogen sulfide, 0.18 ppm of methyl mercaptan, 0.18 ppm of methyl sulfide, and 0 of methyl disulfide. It was .12 ppm, and the malodorous substance removal performance was lower than when 1 month had passed since the start of the deodorization treatment. Table 1 shows the deodorization results after 3 months from the start of the deodorization treatment.
[0020]
Comparative Example 3
Deodorizing treatment was performed under the same conditions as in Example 1 except that the packed layer was filled with a hydrophobic polyurethane foam alone.
After 3 months from the start of the deodorizing treatment, the malodorous substance concentration of the treatment gas is 0.09 ppm hydrogen sulfide, 0.21 ppm methyl mercaptan, 0.16 ppm methyl sulfide, and 0.23 ppm methyl disulfide. Malodorous substance removal performance was low. Thereafter, even if the deodorizing operation was continued for a long time, the malodorous substance removing performance of Example 1 was not reached. The pressure loss of the packed bed maintained a low value of about 40 Pa for a long time. Table 1 shows the deodorization results after 3 months from the start of the deodorization treatment.
[0021]
Comparative Example 4
Deodorizing treatment was performed under the same conditions as in Example 1 except that the highly formalized product of polyvinyl formal was filled alone in the packed layer.
After 3 months from the start of the deodorizing treatment, the malodorous substance concentration of the treatment gas is 0.03 ppm of hydrogen sulfide, 0.15 ppm of methyl mercaptan, 0.11 ppm of methyl sulfide, and 0.08 ppm of methyl disulfide. Malodorous substance removal performance was low. Thereafter, even if the deodorizing operation was continued for a long time, the malodorous substance removing performance of Example 1 was not reached. The pressure loss of the packed bed maintained a low value of about 110 Pa for a long time. Table 1 shows the deodorization results after 3 months from the start of the deodorization treatment.
[0022]
Comparative Example 5
Deodorizing treatment was performed under the same conditions as in Example 1 except that the filler was filled with a low-formalized product of polyvinyl formal alone.
After one month from the start of the deodorization treatment, the concentration of malodorous substances in the treatment gas is 0.001 ppm or less of hydrogen sulfide, 0.001 ppm or less of methyl mercaptan, 0.001 ppm or less of methyl sulfide, and 0.001 ppm or less of methyl disulfide. The malodorous substance removal performance equivalent to 1 was shown. However, the compaction of the packed bed was remarkable, and the pressure loss of the packed bed gradually increased with consolidation. The pressure loss was 550 Pa for the first month and 14,000 Pa for the third month, and the air flow rate was reduced. At this time, the sprinkled water is drifting in the packed bed, and the malodorous substance concentration of the processing gas is 0.001 ppm or less of hydrogen sulfide, 0.008 ppm of methyl mercaptan, 0.014 ppm of methyl sulfide, and methyl disulfide. It was 0.062 ppm, and the malodorous substance removal performance was lowered as compared to the time when one month passed from the start of the deodorizing treatment. Table 1 shows the deodorization results after 3 months from the start of the deodorization treatment.
[0023]
[Table 1]

[0024]
【The invention's effect】
In the present invention, in a biological deodorization apparatus that performs deodorization by ventilating malodorous gas in a packed bed filled with a filler, the packed bed comprises a water absorbent synthetic resin filler and the water absorbent synthetic resin filler. In addition, by mixing and filling a filler having a high compressive strength, high malodorous substance removal performance can be obtained without causing an increase in pressure loss of the packed bed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional configuration diagram showing an example of a biological deodorization apparatus of the present invention.
[Explanation of symbols]
1: Odor gas, 2: Treatment gas, 3: Packing tower, 4: Packing layer, 5: Shape-retaining filler, 6: Water-absorbing filler, 7: Sprinkling water, 8: Sprinkling section, 9: Water distribution pipe

Claims

In a biological deodorization apparatus that performs deodorization by ventilating malodorous gas in a packed layer filled with a filler, the packed layer has a granular water-absorbing synthetic resin filler, and the water-absorbing synthetic resin filler. A biological deodorizing apparatus characterized by being mixed and filled with a granular shape-retaining filler having a high compressive strength.

The mixing ratio of the water-absorbing synthetic resin filler and the shape-retaining filler having a compressive strength greater than that of the water-absorbing synthetic resin filler is such that the water-absorbing synthetic resin filler is 1 volume. The biological deodorization apparatus according to claim 1, wherein the filler having a compressive strength larger than that of the water absorbent synthetic resin filler is 0.1 to 10 volumes.