JP2005013937A - Organic waste water treatment method - Google Patents
Organic waste water treatment method Download PDFInfo
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- JP2005013937A JP2005013937A JP2003184926A JP2003184926A JP2005013937A JP 2005013937 A JP2005013937 A JP 2005013937A JP 2003184926 A JP2003184926 A JP 2003184926A JP 2003184926 A JP2003184926 A JP 2003184926A JP 2005013937 A JP2005013937 A JP 2005013937A
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- 238000004065 wastewater treatment Methods 0.000 title claims abstract description 17
- 239000010815 organic waste Substances 0.000 title abstract description 7
- 239000010802 sludge Substances 0.000 claims abstract description 105
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 65
- 238000011282 treatment Methods 0.000 claims abstract description 64
- 238000000926 separation method Methods 0.000 claims abstract description 40
- 238000000034 method Methods 0.000 claims abstract description 36
- 239000007788 liquid Substances 0.000 claims abstract description 11
- 238000001914 filtration Methods 0.000 claims abstract description 5
- 239000002351 wastewater Substances 0.000 claims description 43
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- 238000009434 installation Methods 0.000 abstract description 5
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- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 239000000945 filler Substances 0.000 description 2
- 239000010800 human waste Substances 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
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- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 229920006317 cationic polymer Polymers 0.000 description 1
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- 238000010586 diagram Methods 0.000 description 1
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- 239000010840 domestic wastewater Substances 0.000 description 1
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/10—Biological treatment of water, waste water, or sewage
Abstract
Description
【0001】
【発明の属する技術分野】
本発明は有機廃水の処理方法に関し、更に詳しくは主に生物化学的酸素要求量(以下、BODという)及び化学的酸素要求量(以下、CODという)の活性汚泥処理方法に関する。
【0002】
本発明の有機廃水処理方法は、従来、標準活性汚泥処理法や長時間曝気処理法に代表される活性汚泥で処理されてきた食品工場、屠場、畜産、塗装、水産加工、皮革、し尿等の有機廃水の処理に対して利用可能である。
【0003】
【従来の技術】
有機廃水を処理するためには、水中の微生物の活性を利用した方法が極めて有効であり、エアー曝気方式の活性汚泥処理法、散水ろ床法、回転円板法、接触曝気法等が知られている。これらの中でも標準活性汚泥法は下水処理や有機廃水を排出する多くの工場廃水処理に利用されている。活性汚泥を用いた生物処理法は水中での微生物の浄化作用を利用した処理方法であることから化学処理のように危険な薬品や難しい操作は必要ないため、比較的容易に採用が可能な反面、微生物の安定した処理能力の維持やそのための運転管理に熟練が必要とされている。
【0004】
本発明に関連した先行技術文献としては以下のものがあげられる。
【特許文献1】
特開2001−29952号公報
【特許文献2】
特開2001−87635号公報
【非特許文献1】
山本和夫 膜分離を用いた新しい排水処理技術(用水と廃水 Vol.41 NO.5(1999))
【0005】
【発明が解決しようとする課題】
活性汚泥を用いて有機廃水を処理する場合、有機物を処理した処理水と活性汚泥を固液分離する際には自然沈降を利用した沈殿槽が一般に用いられている。しかしながら、活性汚泥方式の処理法で処理される廃水には食品工場廃水のようにバルキング(汚泥の膨化現象)を起こし易い廃水が多く、この場合活性汚泥処理後の処理水と活性汚泥の沈殿槽における固液分離が不十分になり、活性汚泥が処理水とともに流出してしまうことがある。そのため処理性が悪化したり、活性汚泥処理槽の汚泥濃度維持が不能になったりして、廃水の処理に支障を来たすおそれがあり、廃水処理の運転維持管理が難しいという問題がある。
【0006】
また、食品工場からの廃水の場合には廃水の水質や水量の変動、季節的変動が多く、廃水処理装置で使用する微生物の能力や廃水処理装置の運転維持管理を考慮した場合、通常運転に際して、これらの変動に対応するために、BOD容積負荷を0.5〜1kg−BOD/m3・D以下で運転しなければならず、活性汚泥処理槽の容量及び設置スペースが大きくなるという問題がある。
【0007】
一方、活性汚泥処理では、槽内の活性汚泥濃度を高め、汚泥負荷を下げることによって高負荷運転する方法が取れるが、この場合には自然沈降を利用した沈殿槽では汚泥濃度が高いため固液分離が不可能となる。近年開発された高負荷型活性汚泥処理装置として、固定床式処理装置に代表される生物膜法による生物ろ過方式の活性汚泥処理があり、これらでは、2〜5kg−BOD/m3・Dの高BOD容積負荷で処理を行っている。これらは活性汚泥の濃度を高めるために、プラスチックスやセラミックス等の充填材(ろ材)を利用しているが、これらの活性汚泥処理には充填材(ろ材)を詰めることによる装置の複雑さ、ろ材箇所への汚泥の閉塞、閉塞による汚泥の嫌気化に基づく悪臭の発生等の問題が生じ、処理性が不安定になるとともに、運転管理が難しいという問題がある。
【0008】
最近採用されている膜分離法は、活性汚泥処理後の処理水と汚泥を分離する際に、従来の沈殿槽に代えて、膜による固液分離を行い、清澄な処理水を得る方法である。この膜分離法は、膜によって固液分離を行なうので、沈殿槽が必要なくなり、従って設置スペースが小さくて済み、沈降性の不良を心配する必要がないので、この膜分離法は比較的水質の安定しているし尿、生活排水、中水道を中心に普及している。しかし、この膜分離法は精密なろ過膜を用いるためその透過水量が 0.2m3/m2・D 以下という少量処理をせざるを得ず、多量の廃水の処理に対しては膜の枚数が多くなるばかりでなく、産業廃水のように多種多様な有機成分を含み、排出水量、水質の変動が激しい廃水に対しては透過水量不足や膜面閉塞等の問題があるため、採用が難しい廃水処理法とされている。特にカルシウム等のスケーリングの原因になる成分を含む廃水は処理対象水として避けられている。更に一般的な廃水でも凝集処理を前処理として用いる場合には、薬品取り扱いの安全性や価格から処理剤の一部として水酸化カルシウムを使用している場合が多く、このような場合にもカルシウムスケールが生成し、膜面を閉塞させる原因となる。従って、前記膜分離法は実用化の障害があり、特に産業廃水の処理技術としては十分でないのが現状である。
【0009】
従って、本発明の目的は、活性汚泥性状変化による処理性の不安定化や処理能力の低下、運転管理の困難さ、処理槽の容積及び設定スペースの増大等の問題を排除して有機廃水を効果的かつ効率的に処理する技術を提供することにある。
【0010】
【課題を解決するための手段】
本発明に従えば、有機廃水を活性汚泥処理するにあたり、廃水処理後の活性汚泥の濃縮又は固液分離に100〜300メッシュの網目スクリーンのろ過板と集水管を配してなる分離装置を用いることを特徴とする有機廃水の処理方法が提供される。
【0011】
【発明の実施の形態】
本発明に従えば、有機廃水を汚泥処理した処理水を透過する網目スクリーンを張ったろ過板及び集水管を内部に備えた分離装置(分離槽)を用いて有機廃水の活性汚泥処理後の活性汚泥の濃縮又は固液分離をする。即ち曝気によって有機廃水を混合攪拌された活性汚泥が分離装置のろ過板表面に活性汚泥フロックの均一な生物膜を形成し、その生物膜を介してろ過した透過水を活性汚泥処理水として集水管を経由して系外に排出する。なお、処理水を排出する方法には、大別して分離装置が活性汚泥処理槽中に浸漬されている場合と、分離装置が活性汚泥処理槽の外部に独立に設置されている場合とがあるが、分離装置の設置場所にかかわらず、曝気槽等の水位より、排水管の位置を下げて、水位差を利用して処理水を排出する方法によることができ、動力を必要としないで処理水を排出することができる。
【0012】
本発明に従えば、前記分離装置を用いることによって、活性汚泥処理槽又は分離槽内の活性汚泥を濃縮し、槽内の活性汚泥濃度を10,000〜20,000mg/リットル 又はそれ以上の高い濃度にすることができるので、汚泥負荷を抑え、BOD 容積負荷を高くして有機廃水を処理することができる。但し、本発明における活性汚泥濃度は上記濃度に限定するものではなく、10,000mg/リットル以下の低活性汚泥濃度においても有機廃水の汚泥処理水を透過することは十分可能であり、この状態で活性汚泥処理を行うこともできる。従って活性汚泥処理を行う際、容積負荷を抑え、汚泥消化領域(BOD汚泥負荷:0.1kg−BOD/kg−MLSS・D以下)で有機廃水を活性汚泥処理することにより、通常の有機物処理量の30〜50%余剰汚泥発生量に対して余剰汚泥発生量を数%以下に抑えることができる。
【0013】
本発明に従えば、前述のように、カルシウムなどの装置のスケーリングの原因となる成分を含む有機廃水の活性汚泥処理に際しても分離装置として比較的網目の粗い100〜300メッシュ、好ましくは190〜210メッシュの網目スクリーンを張ったろ過板を用いてろ過し、処理水を内部の集水管を経由してスムーズに固液分離することができる。なお、ここでメッシュは日本工業規格に基づくメッシュをいう。
【0014】
本発明に従えば、更に活性汚泥処理における固液分離の効率を向上させると共に、分離効率を安定化する手段として、活性汚泥フロック形成薬品、例えば従来から汎用されている高分子系等の汚泥凝集剤を分離装置(分離槽)に添加して、比較的大きく強固な汚泥フロックを形成せしめ、ろ過板上の生物膜を介して処理水を透過することでろ過板の処理水透過能力及び清澄化効果を向上させることができる。
このような活性汚泥凝集剤としては、例えばポリアクリルアミドを主成分とするカチオン系高分子凝集剤などがあげられる。
【0015】
本発明に従った有機廃水の処理方法に用いる汚泥処理は従前の標準活性汚泥法の技術をそのまま用いることができる。
【0016】
以下、添付図面を参照にしながら本発明を更に詳しく説明するが、本発明をこれらの図面の態様に限定するものでないことはいうまでもない。図1及び図2は本発明による有機廃水の活性汚泥処理方法を示す図面であり、図1は活性汚泥処理後の汚泥分離装置が有機廃水の活性汚泥処理槽内に浸漬されている場合を示す図面であり、図2は分離装置が活性汚泥処理槽の外部に設置されている場合を示す図面であり、図3A,B及びCはろ過板一例の詳細を示す図面である。
【0017】
本発明に従えば、処理すべき有機廃水1は、廃水供給ポンプ(図示せず)によりブロワー(図示せず)からのエアー2で曝気された活性汚泥処理槽3に流入させ、ここで有機廃水1中の有機物を分解する。活性汚泥処理水は、図1では分離装置4の網目スクリーン5を張ったろ過板6(図3参照)で活性汚泥フロックが適正な厚みをもったケーキ層となり、ケーキ層と網目スクリーン5を透過した処理水(清澄水)がろ過板6の内部に流入する。網目スクリーン5は、透過、逆洗の際、ろ過板6の内外に変形するのを防ぐためと均一なケーキ層を形成し、また均一な逆洗を行わせるために外側スペーサー7と内側スペーサー8に挟まれた形でろ過板6に固定されている。尚、ろ過板は内部集水パイプ分の厚みを持ち、表面側面と反対側面に網目スクリーンが張られており、それぞれの網目スクリーンが外部スペーサーと内部スペーサーに挟まれている構成をしている。
【0018】
網目スクリーン5を透過した処理水は水面とのヘッド差によりろ過板内集水管9を経て系外へ排出され、処理水槽10に流入する。尚、ヘッド差は100mm〜1000mmの間で任意に設定するのが好ましい。
【0019】
処理水は処理開始数分後にケーキ層が厚みを帯びるに従って透過水量が落ちるが、定期的に処理水を用いて逆洗を数秒〜数十秒間行う。このために逆洗ポンプ11から流入する逆洗水はろ過板内集水パイプ9に開いた孔より均一に流出し、網目スクリーン5に付着しすぎた余分なケーキを剥離する。これらの透過〜逆洗工程を1サイクルとして運転を行い、必要な処理量を得ることができる。
【0020】
また、図2のように分離装置4が活性汚泥処理槽の外部にある場合には、活性汚泥処理槽3の汚泥を汚泥移送ポンプ12で分離装置4へ移送し、同様の経路を経て、必要な処理水を得ることができる。一方、濃縮された汚泥は再び活性汚泥処理槽3へ返送して分離操作を繰り返す。
【0021】
【実施例】
以下、実施例によって本発明を更に説明するが、本発明の範囲をこれらの実施例に限定するものではないことは言うまでもない。
【0022】
実施例1
本例では有機廃水として漬物製造工程廃水を用いた。この廃水の特徴は塩濃度が他の有機廃水に比較して極めて高濃度(2〜3%)であることがあげられる。廃水は前処理工程としてスクリーンで夾雑物を除去した後、有効容量1000リットルの活性汚泥処理装置(図1に示すような分離装置浸漬型)へ廃水をポンプで適量供給した。装置内ではエアー曝気によって混合攪拌された活性汚泥で廃水中の有機物を分解した。活性汚泥処理水の排出は装置内に浸漬した200メッシュ網目スクリーンを張ったろ過板及び内部の集水パイプを介して水位ヘッド差を500mmで透過時間5分間として得た。ろ過板へは処理水を透過するに従い、活性汚泥フロックが適正なケーキ層を形成して付着するが、付着形成されたろ過板面の生物膜は透過時間、透過水量によって厚みを増して透過水量が次第に減少するため、得られた処理水を用いて定期的に逆洗水を10秒間送水し、ろ過面の余分な生物膜を排除することで常に安定した透過水量を確保した。この透過に要する時間や逆洗時間の設定は本例に限定されるものではなく、運転状態によって任意に変えることができるが、通常透過時間は数分〜数十分間、逆洗時間は数秒〜数十秒間に設定して行う。従って必要な処理水量は、透過時間と逆洗時間を1サイクルとしてこれを繰り返し運転することで得る。
【0023】
このようにして得られた処理水のBOD濃度及びその除去性を確認するために、本例ではBOD濃度2,400mg/リットルの廃水に対して活性汚泥濃度20,000mg/リットル、BOD容積負荷0.6kg/m3・日で処理を行った。結果を表Iに示す。
【0024】
【表1】
【0025】
表Iに示すように、本発明の方法により、処理性は標準活性汚泥処理法に比較しても遜色なく、放流に十分な処理水が得られ、99%以上のBOD除去率が達成された。
【0026】
実施例2
本例では同様の食品工場廃水を用いて前処理工程としてスクリーンにより夾雑物を取り除いた後、有効容量1000リットルの活性汚泥処理装置(図1に示すような浸漬型分離装置)へ廃水をポンプで適量供給し、実施例1同様の処理を行った。実施例2では透過時間を5分間、逆洗時間を10秒間とした。
【0027】
このようにして得られた処理水のBOD濃度及び除去性を確認するために本例ではBOD濃度2,400mg/リットルの排水に対して活性汚泥濃度18,000mg/リットル、BOD容積負荷0.5〜3.3kg/m3・日まで廃水通水量を増やすことによりそれぞれの負荷に対して処理を行った。結果を表IIに示す。
【0028】
【表2】
【0029】
表IIに示すように本発明の方法により、処理性は標準活性汚泥処理法に比較して4〜5倍の負荷にもかかわらず安定した処理水が得られ、99%以上のBOD除去率が達成された。
【0030】
実施例3
本例では実施例2の運転方法に加え、処理を施しながらフロック凝集薬剤(富士化水工業(株)製FKフロックF102−K)を原水量に対して20ppm添加して運転を行った。運転結果を表III に示す。表3のように本発明のように添加前と添加後では透過水量が著しく増量している。これによりろ過板枚数を削減することができることから、設備コストの削減につながる。
【0031】
【表3】
【0032】
【発明の効果】
以上説明した通り、本発明に従って100〜300メッシュの網目スクリーンのろ過板と集水管を配してなる分離装置を用いることにより有機廃水の活性汚泥の処理性が向上かつ安定化し、そして運転管理が容易になり、スケーリングを起すことなく高負荷処理することができ、また余剰汚泥の発生を大幅に削減できる活性汚泥処理を行うことができ、同時にフロック形成剤を用いることでさらに設備コスト、設置スペースを軽減することができる。
【図面の簡単な説明】
【図1】本発明に係る有機廃水の活性汚泥処理方法において廃水処理後の活性汚泥の分離装置が活性汚泥処理槽に浸漬されている場合を示した図面である。
【図2】本装置に係る有機廃水の活性汚泥処理方法において廃水処理後の活性汚泥の分離装置が活性汚泥処理槽の外部に設置されている場合を示した図面である。
【図3】図3A,B及びCは図1及び図2に示したろ過板6の構造の詳細の一例を示す図面である。
【符号の説明】
1…有機廃水
2…曝気エアー
3…活性汚泥処理槽
4…分離装置
5…網目スクリーン
6…ろ過板
7…外側スペーサー
8…内側スペーサー
9…ろ過板内部集水パイプ
10…処理水槽
11…逆洗ポンプ
12…汚泥移送ポンプ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for treating organic wastewater, and more particularly to an activated sludge treatment method mainly for biochemical oxygen demand (hereinafter referred to as BOD) and chemical oxygen demand (hereinafter referred to as COD).
[0002]
The organic wastewater treatment method of the present invention is conventionally used in food factories, slaughterhouses, livestock, painting, marine processing, leather, human waste, etc. that have been treated with activated sludge represented by standard activated sludge treatment method and long-time aeration treatment method. It can be used for the treatment of organic wastewater.
[0003]
[Prior art]
In order to treat organic wastewater, methods utilizing the activity of microorganisms in the water are extremely effective, and the activated sludge treatment method using the air aeration method, the watering filter method, the rotating disk method, the contact aeration method, etc. are known. ing. Among these, the standard activated sludge method is used in many factory wastewater treatments that discharge sewage and organic wastewater. The biological treatment method using activated sludge is a treatment method that uses the purification action of microorganisms in water, so it does not require dangerous chemicals or difficult operations like chemical treatment, so it can be adopted relatively easily. Therefore, skill is required to maintain a stable treatment capacity of microorganisms and to manage operations for that purpose.
[0004]
Prior art documents related to the present invention include the following.
[Patent Document 1]
JP 2001-29952 A [Patent Document 2]
JP 2001-87635 A [Non-Patent Document 1]
Kazuo Yamamoto New wastewater treatment technology using membrane separation (water and wastewater Vol.41 NO.5 (1999))
[0005]
[Problems to be solved by the invention]
In the case of treating organic wastewater using activated sludge, a precipitation tank using natural sedimentation is generally used when the treated sludge treated with organic matter and the activated sludge are subjected to solid-liquid separation. However, wastewater treated by the activated sludge treatment method is likely to cause bulking (sludge expansion phenomenon) like food factory wastewater. In this case, the treated water and activated sludge settling tank after activated sludge treatment are used. In some cases, the solid-liquid separation becomes insufficient, and the activated sludge flows out together with the treated water. For this reason, there is a problem in that it is difficult to maintain and manage the wastewater treatment because the processability deteriorates or the sludge concentration in the activated sludge treatment tank cannot be maintained, which may impede the treatment of the wastewater.
[0006]
In addition, wastewater from food factories is subject to many fluctuations in water quality, water volume, and seasonal variations. Considering the ability of microorganisms used in wastewater treatment equipment and the operation and maintenance of wastewater treatment equipment, In order to cope with these fluctuations, the BOD volume load must be operated at 0.5 to 1 kg-BOD / m 3 · D or less, and the capacity and installation space of the activated sludge treatment tank are increased. is there.
[0007]
On the other hand, in activated sludge treatment, a method of high-load operation can be taken by increasing the activated sludge concentration in the tank and reducing the sludge load. In this case, the sedimentation tank using natural sedimentation has a high sludge concentration, Separation becomes impossible. As a high-load activated sludge treatment device developed in recent years, there is a biofiltration type activated sludge treatment by a biofilm method represented by a fixed bed type treatment device, and in these, 2-5 kg-BOD / m 3 · D Processing is performed with a high BOD volumetric load. These use fillers (filter media) such as plastics and ceramics to increase the concentration of activated sludge, but the complexity of the equipment by packing the filler (filter media) in these activated sludge treatments, There is a problem that sludge is blocked in the filter medium, and a bad odor is generated due to the anaerobic formation of sludge due to the blockage, resulting in unstable processability and difficult operation management.
[0008]
The membrane separation method recently adopted is a method for obtaining clear treated water by separating solid-liquid separation with a membrane instead of a conventional sedimentation tank when separating treated water and sludge after activated sludge treatment. . Since this membrane separation method performs solid-liquid separation using a membrane, a sedimentation tank is not required, and therefore the installation space is small, and there is no need to worry about poor sedimentation. It is widely used mainly for stable human waste, domestic wastewater, and waterworks. However, since this membrane separation method uses a precise filtration membrane, the amount of permeated water must be treated in a small amount of 0.2 m 3 / m 2 · D or less. It is difficult to adopt for wastewater containing a wide variety of organic components such as industrial wastewater, and having a large amount of discharged water and water quality, such as insufficient permeate and membrane clogging. It is regarded as a wastewater treatment method. In particular, wastewater containing components that cause scaling such as calcium is avoided as water to be treated. Furthermore, when coagulation treatment is used as a pretreatment even for general wastewater, calcium hydroxide is often used as part of the treatment agent due to the safety and cost of chemical handling. Scales are generated and cause the membrane surface to be blocked. Therefore, the membrane separation method has an impediment to practical use, and is currently not sufficient as an industrial wastewater treatment technique.
[0009]
Accordingly, the object of the present invention is to eliminate organic wastewater by eliminating problems such as instability in treatment due to changes in activated sludge properties, reduction in treatment capacity, difficulty in operation management, increase in volume of the treatment tank and setting space, etc. The object is to provide a technique for effectively and efficiently processing.
[0010]
[Means for Solving the Problems]
According to the present invention, when the activated sludge is treated with the organic wastewater, a separation apparatus comprising a 100 to 300 mesh screen screen and a water collecting pipe is used for concentration or solid-liquid separation of the activated sludge after the wastewater treatment. An organic wastewater treatment method is provided.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
According to the present invention, the activity after the activated sludge treatment of the organic wastewater using the separation device (separation tank) provided with the filter plate with a mesh screen that passes the treated water obtained by sludge treatment of the organic wastewater and the water collecting pipe. Concentrate sludge or solid-liquid separation. That is, the activated sludge mixed and stirred with organic wastewater by aeration forms a uniform biofilm of activated sludge flocs on the filter plate surface of the separator, and the permeated water filtered through the biofilm is used as activated sludge treated water as a water collection pipe. It is discharged out of the system via In addition, the method of discharging treated water can be broadly divided into a case where the separation device is immersed in the activated sludge treatment tank and a case where the separation device is independently installed outside the activated sludge treatment tank. Regardless of the installation location of the separation device, it is possible to use a method that lowers the position of the drain pipe from the water level of the aeration tank, etc., and discharges the treated water using the difference in water level. Can be discharged.
[0012]
According to the present invention, by using the separation device, the activated sludge in the activated sludge treatment tank or the separation tank is concentrated, and the activated sludge concentration in the tank is high from 10,000 to 20,000 mg / liter or more. Since the concentration can be adjusted, the sludge load can be suppressed and the BOD volumetric load can be increased to treat organic wastewater. However, the activated sludge concentration in the present invention is not limited to the above concentration, and it is sufficiently possible to permeate the sludge treated water of organic waste water even at a low activated sludge concentration of 10,000 mg / liter or less. Activated sludge treatment can also be performed. Therefore, when performing activated sludge treatment, the volume load is suppressed, and organic wastewater is treated with activated sludge in the sludge digestion area (BOD sludge load: 0.1 kg-BOD / kg-MLSS · D or less), so that the normal organic matter treatment amount The surplus sludge generation amount can be suppressed to several percent or less with respect to 30 to 50% surplus sludge generation amount.
[0013]
According to the present invention, as described above, in the activated sludge treatment of organic wastewater containing components that cause the scaling of the device such as calcium, the separation device has a relatively coarse mesh of 100 to 300 mesh, preferably 190 to 210. Filtration is performed using a filter plate with a mesh screen, and the treated water can be smoothly separated into solid and liquid via an internal water collection pipe. Here, the mesh refers to a mesh based on Japanese Industrial Standard.
[0014]
According to the present invention, as a means for further improving the efficiency of solid-liquid separation in activated sludge treatment and stabilizing the separation efficiency, activated sludge floc-forming chemicals, for example, sludge agglomeration of conventionally used polymer systems, etc. Add the agent to the separator (separation tank) to form a relatively large and strong sludge floc, and pass the treated water through the biofilm on the filter plate to clarify the treated water permeation capacity and clarification of the filter plate. The effect can be improved.
Examples of such activated sludge flocculants include cationic polymer flocculants mainly composed of polyacrylamide.
[0015]
The sludge treatment used in the organic wastewater treatment method according to the present invention can use the conventional standard activated sludge technique as it is.
[0016]
Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. However, it is needless to say that the present invention is not limited to the embodiments of these drawings. 1 and 2 are drawings showing an activated sludge treatment method for organic wastewater according to the present invention, and FIG. 1 shows a case where the sludge separation apparatus after activated sludge treatment is immersed in an activated sludge treatment tank for organic wastewater. FIG. 2 is a drawing showing a case where the separation device is installed outside the activated sludge treatment tank, and FIGS. 3A, 3B and 3C are drawings showing details of an example of the filter plate.
[0017]
According to the present invention,
[0018]
The treated water that has passed through the
[0019]
Although the amount of permeated water decreases as the cake layer becomes thicker after several minutes from the start of treatment, the treated water is periodically backwashed with treated water for several seconds to several tens of seconds. For this reason, the backwash water flowing in from the
[0020]
Further, when the separation device 4 is outside the activated sludge treatment tank as shown in FIG. 2, the sludge in the activated
[0021]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention further, it cannot be overemphasized that the scope of the present invention is not limited to these Examples.
[0022]
Example 1
In this example, pickle manufacturing process wastewater was used as organic wastewater. A feature of this wastewater is that the salt concentration is extremely high (2 to 3%) compared to other organic wastewaters. Waste water was removed by a screen as a pretreatment process, and then an appropriate amount of waste water was supplied to an activated sludge treatment apparatus (separator immersion type as shown in FIG. 1) having an effective capacity of 1000 liters by a pump. In the apparatus, the organic matter in the wastewater was decomposed with activated sludge mixed and stirred by air aeration. The activated sludge treated water was discharged through a filter plate with a 200-mesh mesh screen immersed in the apparatus and an internal water collecting pipe with a water level head difference of 500 mm and a permeation time of 5 minutes. Activated sludge flocs adhere to the filter plate by forming an appropriate cake layer as the treated water permeates, but the attached biofilm on the surface of the filter plate increases in thickness depending on the permeation time and the amount of permeate. Therefore, the backwash water was periodically sent for 10 seconds using the treated water thus obtained, and an excess biofilm on the filtration surface was eliminated to always ensure a stable amount of permeated water. The time required for the permeation and the setting of the backwash time are not limited to this example, and can be arbitrarily changed depending on the operating state. Usually, the permeation time is several minutes to several tens of minutes, and the backwash time is several seconds. ~ Set for several tens of seconds. Therefore, the necessary amount of treated water can be obtained by repeating this operation with the permeation time and backwash time as one cycle.
[0023]
In order to confirm the BOD concentration of the treated water thus obtained and its removability, in this example, an activated sludge concentration of 20,000 mg / liter and a BOD volume load of 0 for waste water with a BOD concentration of 2,400 mg / liter. The treatment was carried out at 6 kg / m 3 · day. The results are shown in Table I.
[0024]
[Table 1]
[0025]
As shown in Table I, by the method of the present invention, the treatment performance is inferior to that of the standard activated sludge treatment method, sufficient treated water for discharge is obtained, and a BOD removal rate of 99% or more is achieved. .
[0026]
Example 2
In this example, after removing impurities with a screen as a pretreatment process using the same waste water from a food factory, the wastewater is pumped to an activated sludge treatment apparatus (an immersion type separation apparatus as shown in FIG. 1) having an effective capacity of 1000 liters. An appropriate amount was supplied, and the same treatment as in Example 1 was performed. In Example 2, the permeation time was 5 minutes and the backwash time was 10 seconds.
[0027]
In order to confirm the BOD concentration and removability of the treated water thus obtained, in this example, the activated sludge concentration was 18,000 mg / liter and the BOD volume load was 0.5 with respect to the wastewater having a BOD concentration of 2,400 mg / liter. Each load was treated by increasing the wastewater flow rate to ~ 3.3 kg / m 3 · day. The results are shown in Table II.
[0028]
[Table 2]
[0029]
As shown in Table II, according to the method of the present invention, a treated water having a treatability of 4 to 5 times that of the standard activated sludge treatment method can be obtained, and a BOD removal rate of 99% or more is obtained. Achieved.
[0030]
Example 3
In this example, in addition to the operation method of Example 2, operation was performed by adding 20 ppm of floc-flocculating agent (FK floc F102-K manufactured by Fujikasui Industry Co., Ltd.) to the raw water amount while performing the treatment. The operation results are shown in Table III. As shown in Table 3, the amount of permeated water is remarkably increased before and after the addition as in the present invention. As a result, the number of filter plates can be reduced, leading to a reduction in equipment costs.
[0031]
[Table 3]
[0032]
【The invention's effect】
As described above, according to the present invention, the use of a separator comprising a 100-300 mesh screen screen filter plate and a water collecting pipe improves and stabilizes the treatment efficiency of the activated sludge of organic wastewater, and enables operation management. It becomes easy, can process high loads without causing scaling, and can perform activated sludge treatment that can significantly reduce the generation of excess sludge. At the same time, the use of a floc forming agent further increases equipment costs and installation space. Can be reduced.
[Brief description of the drawings]
FIG. 1 is a drawing showing a case where an activated sludge separation apparatus after waste water treatment is immersed in an activated sludge treatment tank in an activated sludge treatment method for organic waste water according to the present invention.
FIG. 2 is a view showing a case where an apparatus for separating activated sludge after wastewater treatment is installed outside an activated sludge treatment tank in an organic sludge activated sludge treatment method according to the present apparatus.
FIGS. 3A, 3B and 3C are diagrams showing an example of the detailed structure of the
[Explanation of symbols]
DESCRIPTION OF
Claims (3)
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Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
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WO2010055776A1 (en) * | 2008-11-11 | 2010-05-20 | 株式会社神鋼環境ソリューション | Water treatment device and water treatment method |
JP2010137216A (en) * | 2008-11-11 | 2010-06-24 | Kobelco Eco-Solutions Co Ltd | Membrane separation activated sludge treatment apparatus and membrane separation activated sludge treatment method |
JP2010207752A (en) * | 2009-03-11 | 2010-09-24 | Kobelco Eco-Solutions Co Ltd | Water treatment device and water treatment method |
JP2010207751A (en) * | 2009-03-11 | 2010-09-24 | Kobelco Eco-Solutions Co Ltd | Water treatment device and water treatment method |
JP2011025187A (en) * | 2009-07-28 | 2011-02-10 | Kobelco Eco-Solutions Co Ltd | Method and apparatus for treating wastewater |
JP2014121692A (en) * | 2012-12-21 | 2014-07-03 | Kubota Kankyo Service Kk | Method for treating organic effluent by using activated sludge |
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2003
- 2003-06-27 JP JP2003184926A patent/JP2005013937A/en active Pending
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
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WO2010055776A1 (en) * | 2008-11-11 | 2010-05-20 | 株式会社神鋼環境ソリューション | Water treatment device and water treatment method |
JP2010137216A (en) * | 2008-11-11 | 2010-06-24 | Kobelco Eco-Solutions Co Ltd | Membrane separation activated sludge treatment apparatus and membrane separation activated sludge treatment method |
JP2010207752A (en) * | 2009-03-11 | 2010-09-24 | Kobelco Eco-Solutions Co Ltd | Water treatment device and water treatment method |
JP2010207751A (en) * | 2009-03-11 | 2010-09-24 | Kobelco Eco-Solutions Co Ltd | Water treatment device and water treatment method |
JP2011025187A (en) * | 2009-07-28 | 2011-02-10 | Kobelco Eco-Solutions Co Ltd | Method and apparatus for treating wastewater |
JP2014121692A (en) * | 2012-12-21 | 2014-07-03 | Kubota Kankyo Service Kk | Method for treating organic effluent by using activated sludge |
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