JP3961835B2 - Sewage treatment plant water quality controller - Google Patents

Description

【００７９】
Ｐ_CN：時刻ｔにおけるＣ／Ｎ比
Ｃ_TOC：流入水ＴＯＣ濃度、Ｃ_TN：流入水全窒素濃度
上記式（１．１）により演算されたＣ／Ｎ比は、信号線６ａを介して制御部８へ入力される。
【００８０】
一方、基準Ｃ／Ｎ比設定器７によって、基準Ｃ／Ｎ比が設定される。
【００８１】
制御部８では、Ｃ／Ｎ比演算部６により演算されたＣ／Ｎ比と基準Ｃ／Ｎ比との偏差に基づき、炭素源注入量目標値が、例えば下記の式（１．２）式に示すような式によって演算され、炭素源注入量目標値となるように、炭素源注入量が調整される。
【００８２】
【数２】

【００８３】
ＳＶＱ_carbon,t：時刻ｔにおける炭素源注入量目標値
Ｐ_CN,t：時刻ｔにおけるＣ／Ｎ比
Ｐ_Cnbase：効率的窒素除去を行なうための基準Ｃ／Ｎ比
Ｑ_in：下水処理場流入流量
Ｃ_carbonTOC：炭素源のＴＯＣ濃度
Ｃ_T-Nin,t：流入水のＴ−Ｎ濃度
一方、基準Ｃ／Ｎ比設定器７によって設定される基準Ｃ／Ｎ比Ｐ_Cnbaseの値は、対象となる下水処理場によって異なるが、効率的な窒素除去を行なうためには、ＢＯＤ／ｔ−Ｎ比として３〜４を確保することが必要であるということから、ＢＯＤ／ＴＯＣ比を加味して、４〜６程度の値を設定することが好ましい。
【００８４】
炭素源のＴＯＣ濃度Ｃ_carbonTOCは、使用する炭素源（メタノール、エタノール、酢酸、廃酢酸、グルコースｅｔｃ）と溶液の濃度が既知であれば、容易に求めることができる。
【００８５】
上記式（１．２）式により演算された炭素源注入量目標値に応じて、炭素源注入量が調整される。
【００８６】
本下水処理場水質制御装置によって、Ｃ／Ｎ比が低下した場合、すなわち効率的窒素除去に必要とされる有機物量が不足した時にのみ、必要量の炭素源を注入することができ、炭素源の過剰注入のない効率的な窒素除去を行なうことができる。
【００８７】
上述したように、本実施の形態による下水処理場水質制御装置では、以下のような効果を得ることができる。
【００８８】
（ａ）制御対象として、炭素源注入ポンプ１９を使用するようにしているため、注入量に応じたＣ／Ｎ比を容易に演算することができ、過剰な炭素源の注入を行なうことなく、効率的窒素除去を行なうために必要とされるＣ／Ｎ比以上の値に保つことが可能となる。
【００８９】
（ｂ）有機物成分を計測するセンサとしてＴＯＣ計４を、窒素成分を計測するセンサとして全窒素計５を使用するようにしているため、正味の有機物、窒素比を演算することが可能となる。
【００９０】
（ｃ）基準Ｃ／Ｎ比設定器７により、基準Ｃ／Ｎ比Ｐ_Cnbaseを設定しさえすれば、全てのパラメータを演算することが可能であるため、パラメータ調整の必要がない。
【００９１】
（ｄ）全窒素計５、ＴＯＣ計４を最初沈殿池２通過後の水配管５１に配しているため、水配管５０に配した場合に比べて、汚れによるセンサ値異常の可能性が少なくなり、また曝気槽に流入する正味のＣ／Ｎ比を演算することが可能となる。
【００９２】
（変形例１）
図１の窒素成分濃度計５、および有機物成分濃度計４の取付位置としては、水配管５０に取り付けるようにしてもよい。
【００９３】
また、最初沈殿池２や流入渠、沈砂池、ポンプ井等、曝気槽の前段部であれば、いずれの位置でも使用することができる。
【００９４】
（変形例２）
図１の有機物成分濃度計４としては、ＴＯＣ計でなくても、ＢＯＤ計、ＣＯＤ計のいずれを使用するようにしてもよい。
【００９５】
また、窒素成分濃度計５としては、全窒素計でなくても、下水処理場に流入する流入水１の窒素成分のほとんどはアンモニア性窒素であることから、アンモニア性窒素濃度計を使用するようにしてもよい。
【００９６】
（変形例３）
図１の窒素成分濃度計５としては、無酸素槽１１内に取り付けられた硝酸性窒素計を使用するようにしてもよい。
【００９７】
（変形例４）
炭素源としては、メタノール、エタノール、酢酸、廃酢酸、グルコース等がある。
【００９８】
また、図１の最初沈殿池２の引抜汚泥、およびそれを発酵させたものを使用するようにしてもよい。
【００９９】
（変形例５）
図１の制御部８によって演算される操作量８ａとしては、炭素源注入量以外に、循環流量、返送流量、曝気風量、炭素源注入量、余剰汚泥流量、返流水流量、初沈バイパス弁のいずれであってもよい。
【０１００】
例えば、制御部８によって演算される操作量８ａが循環流量である場合には、例えば下記の式（１．３）に示されるような演算式によって、目標値が演算される。
【０１０１】
【数３】

【０１０２】
ＳＶＱ_cir,t：時刻ｔにおける炭素源注入量目標値
Ｐ_CN,t：時刻ｔにおけるＣ／Ｎ比
Ｐ_Cnbase：効率的窒素除去を行なうためのＣ／Ｎ比
Ｑ０：定数
Ｋ：比例定数
Ｑ０の定数は、一定流量、もしくは流入流量に対する比率制御の目標値であってもよい。
【０１０３】
これにより、Ｃ／Ｎ比が不足している時には循環流量が増加する方向に、Ｃ／Ｎ比が十分な時には循環流量が減少する方向にそれぞれ制御され、窒素除去を効率的に行なうことができる。
【０１０４】
（変形例６）
図１の制御部８によって演算される操作量８ａとしては、上記記載のもの一つだけを制御するものでなく、複数のものを制御するようにしてもよい。
【０１０５】
例えば、制御部８によって演算される操作量８ａとして、上記炭素源注入量および返流水流量を選択した場合には、Ｃ／Ｎ比が基準Ｃ／Ｎ比設定器７によって設定された値よりも大きい場合には、下記の式（１．４）に示すような形で返流水流量が制御され、またＣ／Ｎ比が基準Ｃ／Ｎ比設定器７によって設定された値よりも小さい場合には、炭素源注入量が前記式（１．２）に示されるような形で制御される。
【０１０６】
このように組み合わせて、切り替え制御するようにしてもよい。
【０１０７】
すなわち、汚泥貯留槽２０から返流される返流水は、下水管から流れてくる流入水に比べて、窒素負荷が高くＣ／Ｎ比が小さいため、返流水量を増加させると、Ｃ／Ｎ比を下げる方向に作用する。
【０１０８】
Ｃ／Ｎ比が大きい場合には、返流水量が多くなる方に制御目標値の演算が行なわれる。
【０１０９】
また、Ｃ／Ｎ比が小さくなってくると、返流水量が少なくなる方に制御目標値の演算を行なう。
【０１１０】
【数４】

【０１１１】
ＳＶＱ_cir,t：時刻ｔにおける炭素源注入量目標値
Ｐ_CN：時刻ｔにおけるＣ／Ｎ比
Ｐ_Cnbase：基準Ｃ／Ｎ比
Ｔ_I ：積分時間
Ｑ０：定数
Ｋ：比例定数
Ｃ／Ｎ比が、基準Ｃ／Ｎ比設定器７によって設定された値よりも小さく、炭素源が不足した場合には、返流水量はゼロの方向に向かい、Ｐ_CN,t＜Ｐ_Cnbaseではゼロとなる。
【０１１２】
一方で、Ｐ_CN,t＜Ｐ_Cnbaseの時は、炭素源注入量は上記のように増加の方向に向かう。
【０１１３】
また、上記のような切り替え制御でなく、同時に二つ以上の操作量を制御するものでもよい。
【０１１４】
（変形例７）
対象プロセスとしては、以下に示すような水処理プロセスのいずれに適用するようにしてもよい。
【０１１５】
標準活性汚泥法
Ａ₂ Ｏ法（嫌気−無酸素−好気法）
ＡＯ法（嫌気−好気法）
硝化内生脱窒法
循環式硝化脱窒法
ＯＤ法
ステップ注入法
回分式活性汚泥法
間欠曝気法
担体投入型活性汚泥法
担体投入Ａ₂ Ｏ法
担体投入ＡＯ法
担体投入硝化内生脱窒法
担体投入循環式硝化脱窒法
担体投入ＯＤ法
担体投入ステップ注入法
担体投入回分式活性汚泥法
担体投入間欠曝気法
凝集剤注入型活性汚泥法
凝集剤注入Ａ₂ Ｏ法
凝集剤注入ＡＯ法
凝集剤注入硝化内生脱窒法
凝集剤注入循環式硝化脱窒法
凝集剤注入ＯＤ法
凝集剤注入ステップ注入法
凝集剤注入回分式活性汚泥法
凝集剤注入間欠曝気法
膜分離型活性汚泥法
膜分離型Ａ₂ Ｏ法
膜分離型ＡＯ法
膜分離型硝化内生脱窒法
膜分離型循環式硝化脱窒法
膜分離型ＯＤ法
膜分離型ステップ注入法
膜分離型回分式活性汚泥法
膜分離型間欠曝気法
なお、上記の他に、担体投入、凝集剤併用型のプロセス、またはＡＯＡＯ法等、各種Ａ₂ Ｏ法の変法のいずれに用いるようにしてもよい。
【０１１６】
（変形例８）
図１の制御部８によって演算される操作量８ａとしては、下水処理場に流入する流入水１のＣ／Ｎ比が演算される時点と曝気槽に流入するまでのタイムラグを考慮した、下記の式（１．５）に示すようなものとしてもよい。
【０１１７】
【数５】

【０１１８】
ＳＶＱ_carbon,t：時刻ｔにおける炭素源注入量目標値
Ｐ_CN：時刻ｔにおけるＣ／Ｎ比
Ｐ_Cnbase：基準Ｃ／Ｎ比
Ｑ_{in,t- Δ t}：時刻ｔ−Δｔにおける下水処理場流入流量
Ｃ_carbonTOC：炭素源のＴＯＣ濃度
Ｃ_T-Nin,t：時刻ｔ−Δｔにおける流入水全窒素濃度
（変形例９）
下水処理場に流入する流入水１の有機物成分濃度を直接計測したものでなくても、紫外線（ＵＶ）強度を計測するＵＶ計により計測された紫外線（ＵＶ）強度と有機物成分濃度との相関関係から、下水処理場に流入する流入水１の有機物成分濃度を求めた換算値を使用するようにしてもよい。
【０１１９】
例えば、化学的酸素要求量（ＣＯＤ）値は、ＵＶ値と一般に高い相関関係にあると言われており、下記の式（１．６）に示すような式によって、ＣＯＤ値を推定することができる。
【０１２０】
【数６】

【０１２１】
Ｃ_COD：ＣＯＤ推定値
Ｃ_UV：ＵＶ計測値
ａ，ｂ：定数
これにより、ＣＯＤ計等の有機物成分濃度計が設置されていないような下水処理場においても、処理対象水の汚れ等の影響を受け難い、より安定的なセンサであるＵＶ計の計測値を利用して、制御を行なうことができる。
【０１２２】
（変形例１０）
図１の制御部８によって演算される操作量８ａ出力としては、偏差（Ｐ_CN,t−Ｐ_CNbase）に一次比例するものでなくとも、偏差に基づいたものであればどのようなものでもよい。
【０１２３】
例えば、偏差の対数ｌｏｇ（Ｐ_CN,t−Ｐ_CNbase）に比例したもの、指数関数ｅｘｐ（Ｐ_CN,t−Ｐ_CNbase）、べき乗（Ｐ_CN,t−Ｐ_CNbase）ⁿ に比例したもの等や、それらを複合したものでもよい。
【０１２４】
（変形例１１）
Ｃ／Ｎ比としては、有機物成分濃度計４および窒素成分濃度計５の各計測値から演算されたものでなくとも、過去の流入水質パターンを利用して予測された予測値を用いて演算されたものであってもよい。
【０１２５】
（変形例１２）
下水処理場に流入する流入水１の流入流量に対する流量比率制御の比率を補正するものや、ＤＯ制御の制御目標値を補正するものであってもよい。
【０１２６】
（変形例１３）
図１のＣ／Ｎ比演算部６に加えて、Ｃ／Ｐ比演算部を備え、これらによって演算されたＣ／Ｎ比、Ｃ／Ｐ比に基づいて、循環流量、返送流量、曝気風量、炭素源注入量、凝集剤注入量、余剰汚泥流量、返流水流量のうちの少なくとも一つのものを調節するようにしてもよい。
【０１２７】
（変形例１４）
図１の好気槽１２の後段部、水配管５２、最終沈殿池１３、水配管６０等、生物学的水処理がほぼ完了している部分に取り付けられた水質センサを用いたフィードバック（ＦＢ）制御により、制御量を補正するようにしてもよい。
【０１２８】
（第２の実施の形態）
図２は、本実施の形態による下水処理場水質制御装置の構成例を示すブロック図であり、図７と同一部分には同一符号を付してその説明を省略し、ここでは異なる部分についてのみ述べる。
【０１２９】
すなわち、本実施の形態による下水処理場水質制御装置は、図２に示すように、前記図７に、有機物成分濃度計測手段であるＴＯＣ計４と、リン成分濃度計測手段である全リン濃度計２５と、Ｃ／Ｐ比演算部６′と、基準Ｃ／Ｐ比設定器７′と、制御部８とを付加した構成としている。
【０１３０】
なお、前記図７における弁２４、水配管５９、初沈バイパス弁２３については、図２ではその図示を省略している。
【０１３１】
ＴＯＣ計４は、前記水配管５１に設置しており、下水処理場に流入する流入水１の有機物成分濃度である全有機炭素量（ＴＯＣ）４ａを計測する。
【０１３２】
全リン濃度計２５は、同水配管５１に設置しており、下水処理場に流入する流入水１のリン成分濃度である全リン濃度２５ａを計測する。
【０１３３】
Ｃ／Ｐ比演算部６′は、ＴＯＣ計４および全リン濃度計２５により計測された全有機炭素量４ａおよび全リン濃度２５ａに基づいて、下水処理場に流入する流入水１のリン成分と有機物成分との比（Ｃ／Ｐ比）６′ａを演算する。
【０１３４】
基準Ｃ／Ｐ比設定器７′は、基準となる基準Ｃ／Ｐ比７′ａを設定する。
【０１３５】
制御部８は、基準Ｃ／Ｐ比設定器７′により設定された基準Ｃ／Ｐ比７′ａとＣ／Ｐ比演算部６′により演算されたＣ／Ｐ比６′ａとの差分に基づいて、下水処理場におけるＰＡＣ注入ポンプ１６の流量を調節する操作量８ａを出力する。
【０１３６】
次に、以上のように構成した本実施の形態による下水処理場水質制御装置の作用について説明する。
【０１３７】
図２において、最初沈殿池２から曝気槽に流入する水配管５１上に取り付けられたＴＯＣ計４の計測値である全有機炭素量（ＴＯＣ）４ａと、全リン計２５の計測値である全リン濃度２５ａは、信号線４ａ，２５ａを介して、Ｃ／Ｐ比演算部６′に入力され、これらを基にＣ／Ｐ比が演算される。
【０１３８】
この場合の演算式としては、例えば下記のような式（２．１）で表わされる。
【０１３９】
【数７】

【０１４０】
Ｐ_CP,t：時刻ｔにおけるＣ／Ｐ比
Ｃ_TOC：流入水ＴＯＣ濃度、
Ｃ_TP：流入水全リン濃度
上記式（２．１）により演算されたＣ／Ｐ比は、信号線６ａ′を介して制御部８へ入力される。
【０１４１】
一方、基準Ｃ／Ｐ比設定器７′によって、基準Ｃ／Ｐ比が設定される。
【０１４２】
制御部８では、Ｃ／Ｐ比演算部６′により演算されたＣ／Ｐ比と基準Ｃ／Ｐ比との偏差に基づき、ＰＡＣ注入量目標値が、例えば下記の式（２．２）式に示すような式によって演算され、ＰＡＣ注入量目標値となるように、ＰＡＣ流量が調整される。
【０１４３】
【数８】

【０１４４】
ＳＶＱ_PAC,t：時刻ｔにおけるＰＡＣ注入量目標値
Ｐ_CP：時刻ｔにおけるＣ／Ｐ比
Ｐ_Cnbase：基準Ｃ／Ｐ比
Ｑ０：定数
Ｋ：比例定数
なお、Ｑ０の定数は、一定流量、もしくは流入流量に対する比率制御の目標値でもよい。
【０１４５】
基準Ｃ／Ｐ比設定器７′によって設定される基準Ｃ／Ｐ比Ｐ_CPbaseの値は、対象となる下水処理場によって異なるが、効率的なリン窒素の同時除去を行なうためには、ＢＯＤ／Ｔ−Ｐ比として２５程度を確保することが必要であるということから、ＢＯＤ／ＴＯＣ比を加味して、３０〜４５程度の値を設定することが好ましい。
【０１４６】
本下水処理場水質制御装置によって、Ｃ／Ｐ比が小さい場合には、生物学的リン除去の効率が低下するため、ＰＡＣの注入量が増大する方向に向かい、逆にＣ／Ｐ比が大きい場合には、ＰＡＣの注入量が減少する方向に向かう。
【０１４７】
上述したように、本実施の形態による下水処理場水質制御装置では、以下のような効果を得ることができる。
【０１４８】
（ａ）制御対象として、ＰＡＣ注入ポンプ１６を使用するようにしているため、Ｃ／Ｐ比が低く生物学的リン除去が困難な場合でも、放流水質のリン濃度を悪化させることなくリン除去を行なうことが可能となる。
【０１４９】
（ｂ）有機物成分を計測するセンサとしてＴＯＣ計４を、リン成分を計測するセンサとして全リン計２５を使用するようにしているため、正味の有機物、リン比を演算することが可能となる。
【０１５０】
（ｃ）基準Ｃ／Ｐ比設定器７′により基準Ｃ／Ｐ比Ｐ_CPbaseを設定しさえすれば、パラメータはＫとＱ０の二つと少なく、パラメータ調整を比較的容易に行なうことが可能となる。
【０１５１】
（ｄ）全リン計２５、ＴＯＣ計４を最初沈殿池２通過後の水配管５１に配しているため、水配管５０に配した場合に比べて、汚れによるセンサ値異常の可能性が少なくなり、また曝気槽に流入する正味のＣ／Ｐ比を演算することが可能となる。
【０１５２】
（変形例１）
図２のリン成分濃度計２５、および有機物成分濃度計４の取付位置としては、水配管５０に取り付けるようにしてもよい。
【０１５３】
また、最初沈殿池２や流入渠、沈砂池、ポンプ井等、曝気槽の前段部であれば、いずれの位置でも使用することができる。
【０１５４】
（変形例２）
図２の有機物成分濃度計４としては、ＴＯＣ計でなくても、ＢＯＤ計、ＣＯＤ計のいずれを使用するようにしてもよい。
【０１５５】
また、リン成分濃度計２５としては、全リン計でなくても、下水処理場に流入する流入水１のリン成分のほとんどはリン酸性リンであることから、リン酸性リン濃度計を使用するようにしてもよい。
【０１５６】
（変形例３）
図２の全リン計２５としては、嫌気槽１０内に取り付けられたリン酸性リン計を使用するようにしてもよい。
【０１５７】
（変形例４）
図２の制御部８によって演算される操作量８ａとしては、ＰＡＣ（凝集剤）注入量以外に、返送流量、曝気風量、炭素源注入量、余剰汚泥流量、返流水流量のいずれであってもよい。
【０１５８】
（変形例５）
図２の制御部８によって演算される操作量８ａとしては、上記記載のもの一つだけを制御するものでなく、複数のものを制御するようにしてもよい。
【０１５９】
（変形例６）
対象プロセスとしては、前述したような水処理プロセスのいずれに適用するようにしてもよい。
【０１６０】
また、担体投入、凝集剤併用型のプロセス、またはＡＯＡＯ法等、各種Ａ₂ Ｏ法の変法のいずれに用いるようにしてもよい。
【０１６１】
（変形例７）
図２の制御部８によって演算される操作量８ａとしては、下水処理場に流入する流入水１のＣ／Ｐ比が演算される時点と曝気槽に流入するまでのタイムラグを考慮したものとしてもよい。
【０１６２】
（変形例８）
下水処理場に流入する流入水１の有機物成分濃度を直接計測したものでなくても、紫外線（ＵＶ）強度を計測するＵＶ計により計測された紫外線（ＵＶ）強度と有機物成分濃度との相関関係から、下水処理場に流入する流入水１の有機物成分濃度を求めた換算値を使用するようにしてもよい。
【０１６３】
（変形例９）
Ｃ／Ｐ比は、有機物成分濃度計と窒素成分濃度計の計測値から演算されたものでなくとも、後述するような手法で予測された予測値を用いたものであっても良い。（請求項１０の発明）
（変形例１０）
図２の制御部８によって演算される操作量８ａ出力としては、偏差（Ｐ_CN,t−Ｐ_CNbase））に一次比例するものでなくとも、偏差に基づいたものであればどのようなものでもよい。
【０１６４】
例えば、偏差の対数ｌｏｇ（Ｐ_CN,t−Ｐ_CNbase）に比例したもの、指数関数ｅｘｐ（Ｐ_CN,t−Ｐ_CNbase）、べき乗（Ｐ_CN,t−Ｐ_CNbase）ⁿ に比例したもの等や、それらを複合したものでもよい。
【０１６５】
（変形例１１）
Ｃ／Ｐ比としては、有機物成分濃度計４およびリン成分濃度計２５の各計測値から演算されたものでなくとも、過去の流入水質パターン等を利用して予測された予測値を用いて演算されたものであっても良い。
【０１６６】
（変形例１２）
下水処理場に流入する流入水１の流入流量に対する流量比率制御の比率を補正するものや、ＤＯ制御の制御目標値を補正するものであってもよい。
【０１６７】
（変形例１３）
図２のＣ／Ｐ比演算部６′に加えて、Ｃ／Ｎ比演算部を備え、これらによって演算されたＣ／Ｎ比、Ｃ／Ｐ比に基づいて、循環流量、返送流量、曝気風量、炭素源注入量、凝集剤注入量、余剰汚泥流量、返流水流量のうちの少なくとも一つのものを調節するようにしてもよい。
【０１６８】
（変形例１４）
図２の好気槽１２の後段部、水配管５２、最終沈殿池１３、水配管６０等、生物学的水処理がほぼ完了している部分にとりつけられた水質センサを用いたフィードバック（ＦＢ）制御により、制御量を補正するようにしてもよい。
【０１６９】
（第３の実施の形態）
図３は、本実施の形態による下水処理場水質制御装置の構成例を示すブロック図であり、図４と同一部分には同一符号を付してその説明を省略し、ここでは異なる部分についてのみ述べる。
【０１７０】
すなわち、本実施の形態による下水処理場水質制御装置は、図３に示すように、前記図４に、紫外線計測手段であるＵＶ計３０と、流量計測手段である流量計３１と、ＮＨ₄ 計３２と、窒素成分濃度計測手段であるＴ−Ｎ計３３と、リン成分濃度計測手段であるＴ−Ｐ計３４と、流入水質データベース２６と、気象情報予測部２７と、流入水質パターンデータベース２８と、流入水質予測部２９と、基準Ｃ／Ｎ比Ｃ／Ｐ比設定器７″と、ＵＶ→ＢＯＤ換算器３７と、Ｃ／Ｎ比Ｃ／Ｐ比演算部６″と、流入比率設定器３８と、制御部８と、処理水質判定部３６と、制御補正部３５とを付加した構成としている。
【０１７１】
なお、前記図７における弁２４、水配管５９、初沈バイパス弁２３、炭素源貯留槽２１、炭素源注入ポンプ１９、水配管５７については、図３ではその図示を省略している。
【０１７２】
ＵＶ計３０は、前記水配管５１に設置しており、下水処理場に流入する流入水１の紫外線（ＵＶ）強度を計測する。
【０１７３】
流量計３１は、同水配管５１に設置しており、下水処理場に流入する流入水１の流量を計測する。
【０１７４】
ＮＨ₄ 計３２は、前記好気槽１２に設置しており、好気槽１２内のアンモニア濃度を計測する。
【０１７５】
Ｔ−Ｎ計３３は、前記水配管６１に設置しており、処理水３の全窒素濃度を計測する。
【０１７６】
Ｔ−Ｐ計３４は、同水配管６１に設置しており、処理水３の全リン濃度を計測する。
【０１７７】
流入水質データベース２６は、ＵＶ計３０により計測された紫外線（ＵＶ）強度、ＮＨ₄ 計３２により計測されたアンモニア濃度、Ｔ−Ｎ計３３により計測された全窒素濃度、Ｔ−Ｐ計３４により計測された全リン濃度、流量計３１により計測された流量、および日常の水質試験である手分析による水質試験結果の各時系列データを蓄える。
【０１７８】
気象情報予測部２７は、気象情報を予測する。
【０１７９】
流入水質パターンデータベース２８は、流入水質データベース２６に蓄積されたデータに基づいて、流入水質パターンを作成し記憶する。
【０１８０】
流入水質予測部２９は、流入水質パターンデータベース２８に蓄えられたＴ−Ｎの水質パターンと、気象情報予測部２７二より予測された気象情報とに基づいて、下水処理場に流入する流入水の窒素成分濃度、リン成分濃度、有機物成分濃度のうちの少なくとも一つを予測する。
【０１８１】
基準Ｃ／Ｎ比Ｃ／Ｐ比設定器７″は、基準Ｃ／Ｎ比、および基準Ｃ／Ｐ比を設定する。
【０１８２】
ＵＶ→ＢＯＤ換算器３７は、ＵＶ計３０により計測された紫外線（ＵＶ）強度を、生物化学的酸素要求量（ＢＯＤ）に換算する。
【０１８３】
Ｃ／Ｎ比Ｃ／Ｐ比演算部６″は、流入水質予測部２９により予測された窒素成分濃度、リン成分濃度、有機物成分濃度と、Ｎ比Ｃ／Ｐ比基準設定器７″により設定された基準Ｃ／Ｎ比、基準Ｃ／Ｐ比と、ＵＶ→ＢＯＤ換算器３７により換算されたＢＯＤとに基づいて、Ｃ／Ｎ比、Ｃ／Ｐ比を演算する。
【０１８４】
流入比率設定器３８は、下水処理場に流入する流入水１の流量に対する曝気風量、循環流量、ＰＡＣ注入流量の比率を設定する。
【０１８５】
制御部８は、Ｃ／Ｎ比Ｃ／Ｐ比演算部６″により演算されたＣ／Ｎ比、Ｃ／Ｐ比とＣ／Ｎ比Ｃ／Ｐ比基準設定器７″により設定された基準Ｃ／Ｎ比、基準Ｃ／Ｐ比それぞれの偏差に基づいて、曝気装置９、循環ポンプ１４、ＰＡＣ注入ポンプ１６を調節するの操作量を出力する。
【０１８６】
処理水質判定部３６は、ＮＨ₄ 計３２により計測されたアンモニア濃度と、Ｔ−Ｎ計３３により計測された全窒素濃度と、Ｔ−Ｐ計３４により計測された全リン濃度とに基づいて、処理水３の水質状態を判定する。
【０１８７】
制御補正部３５は、処理水質判定部３６により判定された処理水３の水質状態と、あらかじめ設定された水質成分の目標値との差分に基づいて、制御部８から出力される曝気装置９、循環ポンプ１４、ＰＡＣ注入ポンプ１６に対する操作量を補正する。
【０１８８】
次に、以上のように構成した本実施の形態による下水処理場水質制御装置の作用について、図４乃至図６に示す関係図を用いて説明する。
【０１８９】
図３において、最初沈殿池２から嫌気槽１０に接続される水配管５１上に取り付けられたＵＶ計３０の計測値である紫外線強度が、ＵＶ→ＢＯＤ換算器３７によってＢＯＤ値に換算され、信号線を介して、Ｃ／Ｎ比Ｃ／Ｐ比演算部６″に入力される。
【０１９０】
下水処理場に流入する流入水１の流入水質である窒素成分濃度、およびリン成分濃度は、下記に示すような方法で予測される。
【０１９１】
流入水質データベース２６には、日常の水質試験により測定された水質の時系列データと流量計３１による流量計測値、およびＵＶ計３０によるＵＶ計測値の時系列データが保持されている。
【０１９２】
【表１】

【０１９３】
流入水質パターンデータベース２８には、天候、降雨量、降雨継続時間、降雨強度、気温等の気象情報、季節、平日、日曜等、日イベント毎に流入水質パターンが記憶されている。
【０１９４】
これは、流入水質データベース２６に蓄積されたデータより作成されるものであるが、この流入水質パターンは、下水処理場のオペレータが自由に変更することができる。
【０１９５】
例えば、図４は、平日、夏、晴れの日の流入Ｔ−Ｎ変動パターンを示す図である。
【０１９６】
Ｔ−Ｎの水質パターンは、図４に示すように午前中にピークがある。
【０１９７】
Ｔ−Ｐの水質パターンも、同様に午前中にピークがある。
【０１９８】
なお、図４中、○印は、流入水質データベース２６に蓄えられたデータである。
【０１９９】
流入水質予測部２９では、その日の日イベントと気象情報予測部２７によって予測された気象情報を基に類似日を選び出し、その日のＴ−Ｎの水質パターンが水質パターンデータベース２８から選び出される。
【０２００】
この場合、もし、その日のある時刻にＴ−Ｎが測定され、その値が流入水質データベース２６に入力されれば、そのデータを基に、例えば図５に示すように、異なるＴ−Ｎの水質パターンが選定され、日変動パターンが補正される。
【０２０１】
また、流量計３１の計測値、ＵＶ計３０による計測値等、流入水質データベース２６に蓄積されてくるデータにより、類似日を再検索して、日変動パターンが随時更新される。
【０２０２】
この流入水質予測部２９で予測されたＴ−Ｎ濃度、Ｔ−Ｐ濃度は、信号線を介してＣ／Ｎ比Ｃ／Ｐ比演算部６″に入力される。
【０２０３】
Ｃ／Ｎ比Ｃ／Ｐ比演算部６″では、下記の式（３．１）、式（３．２）に基づき、Ｃ／Ｎ比、Ｃ／Ｐ比が、それぞれ演算される。
【０２０４】
【数９】

【０２０５】
Ｐ_CN,t：時刻ｔにおけるＣ／Ｎ比
Ｃ_BOD：流入水ＢＯＤ濃度換算値、
Ｃ_TN：流入水全窒素濃度予測値
【数１０】

【０２０６】
Ｐ_CP,t：時刻ｔにおけるＣ／Ｐ比
Ｃ_BOD：流入水ＢＯＤ濃度換算値、
Ｃ_TP：流入水全リン濃度予測値
一方、流入比率設定部３８によって、流入流量に対する曝気風量、循環流量、ＰＡＣ注入流量の比率Ｒblow，Ｒcir，Ｒpacが、それぞれ設定される。
【０２０７】
そして、このＣ／Ｎ比Ｃ／Ｐ比演算部６″により演算されたＣ／Ｎ比、Ｃ／Ｐ比と、基準Ｃ／Ｎ比Ｃ／Ｐ比設定器７″により設定された基準Ｃ／Ｎ比、基準Ｃ／Ｐ比とのそれぞれの偏差に基づいて、循環流量とＰＡＣ注入量の流入流量に対する比率が補正される。
【０２０８】
【数１１】

【０２０９】
ＳＶＱ_blow,t：曝気風量目標値
ＳＶＱ_cir,t：循環流量目標値
ＳＶＱ_pac,t：ＰＡＣ流量目標値
Ｑ_in,t：時刻ｔにおける流入流量
Ｐ_CNbase：基準Ｃ／Ｎ比
Ｐ_CPbase：基準Ｃ／Ｐ比
Ｓblow，Ｓcir，Ｓpac：制御補正量
Ｋ１，Ｋ２：定数
【０２１０】
【数１２】

【０２１１】
Ｃ_NH4,t：時刻ｔにおけるアンモニア性窒素濃度
Ｃ_T-N,t：時刻ｔにおける全窒素濃度
Ｃ_T-P,t：時刻ｔにおける全リン濃度
Ｋ３，Ｋ４，Ｋ５：定数
上記式（３．３）〜式（３．５）により、Ｃ／Ｎ比が不足した場合には、循環流量が増加し、Ｃ／Ｐ比が不足した場合には、ＰＡＣ注入量が増加する。
【０２１２】
制御補正量（Ｓblow，Ｓcir，Ｓpac）は、下記の式（３．６）〜式（３．８）によって、それぞれ演算される。
【０２１３】
最終沈殿池１３通過後の配管６０に取り付けられたＴ−Ｎ計３３の計数値、Ｔ−Ｐ計３４の計数値、およびＮＨ₄ 計３２の計数値を基に、処理水３の水質状態を判定する処理水質判定部３６により、Ｔ−Ｎ，Ｔ−Ｐの処理が悪化傾向にあると判定された場合に、補正がかけられる。
【０２１４】
すなわち、例えば図６（ａ）〜（ｃ）に示すように、（１）Ｔ−Ｎ計３３，Ｔ−Ｐ計３４の計測値が連続的に上昇している場合（図６（ａ））、（２）Ｔ−Ｎ計３３，Ｔ−Ｐ計３４の計測値が処理悪化判定値以上になり一定時間経った場合（図６（ｂ））、（３）Ｔ−Ｎ計３３，Ｔ−Ｐ計３４の計測値がある一定の時間幅の中で急激な濃度上昇があった場合（図６（ｃ））等に、処理水３の水質が悪化したと判定される。
【０２１５】
このようなことから、処理水質判定部３６で処理水の悪化が判定された場合には、次のようなロジックによって制御量が補正される。
【０２１６】
（１）処理水Ｔ−Ｎが悪化し、好気槽１２内のＮＨ₄ 計３２による計測値が、ある一定の基準値よりも高い場合には、例えば上記式（３．６）によって曝気風量に補正がかけられる。
【０２１７】
（２）処理水Ｔ−Ｎが悪化し、処理水Ｔ−Ｎ計３３の計測値と好気槽１２内のＮＨ₄ 計３２による計測値との差がある一定以上である場合には、脱窒処理が不良と判定し、例えば上記式（３．７）によって循環流量に補正がかけられる。
【０２１８】
（３）処理水Ｔ−Ｐが悪化した場合には、例えば上記式（３．８）によってＰＡＣ流量に補正がかけられる。
【０２１９】
上述したように、本実施の形態による下水処理場水質制御装置では、以下のような効果を得ることができる。
【０２２０】
（ａ）下水処理場に流入する流入水１の窒素成分濃度、リン成分濃度としては、予測値を用いるようにしているため、窒素成分濃度計、リン成分濃度計が取り付けられないような機場でも、適用することが可能となる。
【０２２１】
（ｂ）有機物成分濃度計の代わりに、比較的高精度で連続測定が可能なＵＶ計３０を利用して、有機物成分濃度を測定するようにしているため、より一層効果的な制御を実施することが可能となる。
【０２２２】
（ｃ）放流水質の全窒素、全リン計の計測値を用いて、フィードバック（ＦＢ）制御により操作量を補正するようにしているため、処理水３の水質を悪化させることがなく制御を行なうことが可能となる。
【０２２３】
（ｄ）好気槽１２に取り付けられたアンモニア計３２によって、処理水３の全窒素の悪化が硝化不良によるものなのか脱窒不良によるものなのかを判定して、曝気風量、循環流量を制御するようにしているため、より一層効率的な窒素除去を行なうことが可能となる。
【０２２４】
（変形例１）
図３の流量計３１、およびＵＶ計３０の取付位置としては、水配管５０に取り付けるようにしてもよい。
【０２２５】
また、最初沈殿池２や流入渠、沈砂池、ポンプ井等、曝気槽の前段部であれば、いずれの位置でも使用することができる。
【０２２６】
さらに、流量計３１の代わりに、ポンプ井に設置される水位計の計測値から、Ｑ−Ｈカーブで流量を演算したものを使用することもできる。
【０２２７】
（変形例２）
紫外線（ＵＶ）強度ではなく、有機物成分を直接測定する濃度計の計測値を有機物成分濃度として用いるようにしてもよい。
【０２２８】
（変形例３）
下水処理場に流入する流入水１のリン成分濃度および窒素成分濃度としては、水配管５０，５１、最初沈殿池２や流入渠、沈砂池、ポンプ井等、曝気槽の前段部に取り付けられたＴ−Ｐ計、ＰＯ₄ 計およびＴ−Ｎ計、ＮＨ₄ 計の計測値を利用するようにしてもよい。
【０２２９】
（変形例４）
水配管５０，５１、最初沈殿池２や流入渠、沈砂池、ポンプ井等、曝気槽の前段部にＴ−Ｐ計、ＰＯ₄ 計およびＴ−Ｎ計、ＮＨ₄ 計が取り付けられているような下水処理場においても、流入水質パターン予測により予測された値を用いて、制御を行なうようにしてもよい。
【０２３０】
（変形例５）
図１の制御部８によって演算される操作量８ａとしては、循環流量、返送流量、曝気風量、炭素源注入量、凝集剤注入量、余剰汚泥流量、返流水流量、初沈バイパス弁のうちの少なくともいずれか一つであってもよい。
【０２３１】
（変形例６）
図３の処理水３のＴ−Ｎ計３３、およびＴ−Ｐ計３４の取付位置としては、水配管６０の位置でなくとも、好気槽１２の後段部、水配管５２、最終沈殿池１３等、生物学的水処理がほぼ完了している部分であればいずれの位置であってもよい。
【０２３２】
（変形例７）
制御補正用に処理水３の窒素成分を計測する窒素成分濃度計５としては、Ｔ−Ｎ計３３でなくとも、アンモニア性窒素濃度、硝酸性窒素濃度、亜硝酸性窒素濃度のうちいずれであってもよく、また一つでなく複数を用いて補正を行なうようにしてもよい。
【０２３３】
（変形例８）
制御補正用に処理水３のリン成分を計測するリン成分濃度計としては、Ｔ−Ｐ計３４でなくとも、リン酸性リン濃度であってもよく、また一つでなく複数を用いて補正を行なうようにしてもよい。
【０２３４】
（変形例９）
制御補正は、好気槽１２の後段部、水配管５２、最終沈殿池１３、水配管６０等、生物学的水処理がほぼ完了している部分に取り付けられたＤＯ計、ＯＲＰ計、ｐＨ計、ＳＳ計、ＭＬＳＳ計、ＵＶ計等の水質センサ等、いずれを用いて行なうようにしてもよい。
【０２３５】
（変形例１０）
図３の制御部８によって演算される操作量出力としては、上記に示すような偏差に一次比例するものでなくとも、偏差に基づいたものであればどのようなものでもよい。
【０２３６】
例えば、偏差の対数に比例したもの、指数関数、べき乗に比例したもの等や、それらを複合したものでもよい。
【０２３７】
（変形例１１）
制御補正部３５よる出力としては、偏差に一次比例するものでなくとも、偏差に基づいたものであればどのようなものでもよい。
【０２３８】
例えば、偏差の対数に比例したもの、指数関数、べき乗に比例したもの等や、それらを複合したものでもよい。
【０２３９】
（その他の実施の形態）
尚、本発明は、上記各実施の形態に限定されるものではなく、実施段階ではその要旨を逸脱しない範囲で、種々に変形して実施することが可能である。
例えば、上記各実施の形態では、嫌気槽と無酸素槽と好気槽との組み合わせから構成される曝気槽を備えた下水処理場に本発明を適用した場合について説明したが、これに限らず、無酸素槽と好気槽との組み合わせから構成される曝気槽を備えた下水処理場についても、本発明を前述と同様に適用して同様の作用効果を得ることができる。
【０２４０】
また、各実施の形態は可能な限り適宜組合わせて実施してもよく、その場合には組合わせた作用効果を得ることができる。
さらに、上記各実施の形態には種々の段階の発明が含まれており、開示される複数の構成要件における適宜な組合わせにより、種々の発明を抽出することができる。
例えば、実施の形態に示される全構成要件から幾つかの構成要件が削除されても、発明が解決しようとする課題の欄で述べた課題（の少なくとも一つ）が解決でき、発明の効果の欄で述べられている効果（の少なくとも一つ）が得られる場合には、この構成要件が削除された構成を発明として抽出することができる。
【０２４１】
【発明の効果】
以上説明したように、本発明の下水処理場水質制御装置によれば、流入水の窒素成分と有機物成分とのＣ／Ｎ比、または／およびリン成分と有機物成分とのＣ／Ｐ比を用いて、下水処理場における循環流量、返送流量、曝気風量、炭素源注入量、余剰汚泥流量、返流水流量、初沈バイパス弁のうちの少なくとも一つを制御するようにしているので、下水処理場に流入する流入水の窒素成分と有機物成分とのＣ／Ｎ比、リン成分と有機物成分とのＣ／Ｐ比等の水質バランスが悪化したような場合においても、下水処理場から放流される処理水の窒素、リンの水質を常に良好に維持して、窒素、リン除去を行なうことが可能となる。
【図面の簡単な説明】
【図１】本発明による下水処理場水質制御装置の第１の実施の形態を示すブロック図。
【図２】本発明による下水処理場水質制御装置の第２の実施の形態を示すブロック図。
【図３】本発明による下水処理場水質制御装置の第３の実施の形態を示すブロック図。
【図４】同第３の実施の形態による下水処理場水質制御装置における作用を説明するための関係図。
【図５】同第３の実施の形態による下水処理場水質制御装置における作用を説明するための関係図。
【図６】同第３の実施の形態による下水処理場水質制御装置における作用を説明するための関係図。
【図７】凝集剤注入型嫌気−無酸素−好気法（凝集剤注入Ａ₂ Ｏ法）のプロセスから構成される曝気槽を備えた下水処理場の構成例を示すフロー図。
【図８】従来の下水処理場水質制御装置の一構成例を示すブロック図。
【符号の説明】
１…流入水
２…最初沈殿池
３…処理水
４…ＴＯＣ計
５…Ｔ−Ｎ計
６…Ｃ／Ｎ比演算部
６′…Ｃ／Ｐ比演算部
６″…Ｃ／Ｎ比、Ｃ／Ｐ比演算部
７…基準Ｃ／Ｎ比設定器
７′…基準Ｃ／Ｐ比設定器
７″…基準Ｃ／Ｎ比、Ｃ／Ｐ比設定器
８…制御部
９…曝気装置
１０…嫌気槽
１１…無酸素槽
１２…好気槽
１３…最終沈殿池
１４…循環ポンプ
１５…返送ポンプ
１６…ＰＡＣ注入ポンプ
１７…余剰ポンプ
１８…初沈引抜ポンプ
１９…炭素源注入ポンプ
２０…汚泥貯留槽
２１…炭素源貯留槽
２２…凝集剤貯留槽
２３…初沈バイパス弁
２４…弁
２５…Ｔ−Ｐ計
２６…流入水質データベース
２７…気象情報予測部
２８…水質パターンデータベース
２９…流入水質予測部
３０…ＵＶ計
３１…流量計
３２…ＮＨ₄ 計
３３…Ｔ−Ｎ計
３４…Ｔ−Ｐ計
３５…制御補正部
３６…処理水質判定部
３７…ＵＶ→ＢＯＤ換算器
３８…流入比率設定器
５０〜６０…水配管。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sewage treatment plant water quality control device for controlling the quality of treated water discharged from a sewage treatment plant equipped with an aeration tank, and in particular, a ratio of nitrogen components and organic components of influent water flowing into the sewage treatment plant. (C / N ratio), even if the water quality balance such as the ratio of phosphorus component to organic component (C / P ratio) deteriorates, the quality of nitrogen and phosphorus in the treated water discharged from the sewage treatment plant The present invention relates to a water quality control device for a sewage treatment plant that can always be maintained well.
[0002]
[Prior art]
In recent years, eutrophication has progressed in closed water areas such as lakes and bays, and it is necessary to suppress the outflow of these causative substances from nitrogen and phosphorus sewage treatment plants to closed water areas.
[0003]
For this reason, in conventional sewage treatment plants, organic substances have been removed by a process called activated sludge process, but recently, due to the progress of eutrophication in closed water areas such as lakes and bays, nitrogen has been removed. There is an increasing demand for advanced treatments that also remove phosphorus.
[0004]
And, as a sewage treatment plant to meet such demands, influent water flowing into the sewage treatment plant using biological nitrification denitrification reaction, biological dephosphorization reaction, dephosphorization reaction by adding flocculant, etc. Sewage treatment plants with aeration tanks that remove nitrogen or phosphorus have been realized.
[0005]
FIG. 7 shows a coagulant injection type anaerobic-anoxic-aerobic method (coagulant injection A) which is one of the advanced treatment processes for denitrification and dephosphorization among the various water treatment processes described above.₂It is a flowchart which shows the structural example of the sewage treatment plant provided with the aeration tank comprised from the process called O method.
[0006]
In FIG. 7, one of the inflow water 1 flowing into the sewage treatment plant flows into the first sedimentation basin 2 through the water pipe 50 and the valve 24, and the anaerobic tank 10 and the anoxic tank through the water pipe 51. 11 and an aerobic tank 12 provided with an aeration device 9 flows into the anaerobic tank 10 of the aeration tank.
[0007]
The other is that after flowing into the anaerobic tank 10 through the water pipe 50, the water pipe 59, and the initial settling bypass valve 23, the water pipe 52, the final settling tank 13, and the water pipe 60 are connected after being processed by the aeration tank. Then, it is discharged as treated water 3.
[0008]
On the other hand, the carbon source is injected from the carbon source storage tank 21 into the anaerobic tank 10 via the carbon source injection pump 19 and the water pipe 57.
[0009]
Further, the flocculant is injected into the aerobic tank 12 from the flocculant storage tank 22 via the PAC injection pump 16 and the water pipe 56.
[0010]
On the other hand, the non-treated water in the aerobic tank 12 is returned to the anoxic tank 11 through the water pipe 53 and the circulation pump 14.
[0011]
Further, the precipitated water in the final settling tank 13 is returned to the anaerobic tank 10 via the water pipe 54 and the return pump 15.
[0012]
Furthermore, the final sludge water in the final sedimentation basin 13 is discharged into the sludge storage tank 20 via the water pipe 55 and the surplus pump 17.
[0013]
Furthermore, the first settling sludge water in the first settling basin 2 is discharged to the sludge storage tank 20 via the first settling / pumping pump 18 and the water pipe 58.
[0014]
In the sewage treatment plant equipped with the aeration tank as described above, first, nitrogen removal is performed as follows.
[0015]
In the aerobic tank 12, ammoniacal nitrogen (NH_Four-N) is nitrite nitrogen (NO) by the action of nitrifying bacteria.₂-N), nitrate nitrogen (NO_ThreeOxidized to -N).
[0016]
Nitrite nitrogen (NO) fed into the anoxic tank 11 by the circulation pump 14₂-N), nitrate nitrogen (NO_Three-N) is nitrogen gas (N) due to nitrate respiration or nitrite respiration by denitrifying bacteria using organic matter as a nutrient source under anoxic conditions.₂) To be removed from the system.
[0017]
At this time, good nitrogen removal is not performed unless the organic matter necessary for the denitrification reaction is sufficient.
[0018]
As means for replenishing this organic matter, by opening the primary sedimentation bypass valve 23 and closing the valve 24, by bypassing the primary sedimentation basin 2 and securing the organic matter, methanol stored in the carbon source storage tank 21, There are a method of injecting a carbon source such as ethanol, acetic acid, waste acetic acid, glucose and the like, and a method of introducing the extracted sludge generated in the first sedimentation tank 2 into an aeration tank.
[0019]
Next, phosphorus removal is performed by the following mechanism.
[0020]
In the anaerobic tank 10 arranged in the front stage of the aeration tank, phosphorus accumulating bacteria in the activated sludge accumulate organic acids such as acetic acid in the body, and phosphoric acid (PO_Four) Is released.
[0021]
This excessively released phosphorous phosphorus is in the aerobic tank 12 arranged at the rear stage of the aeration tank, using the phosphorus excessive intake action of the phosphorus accumulating bacteria, more than the phosphate state released in the anaerobic tank 10. Phosphorus removal is performed by absorbing activated phosphorus in activated sludge.
[0022]
That is, in order to proceed such a reaction, an organic acid such as acetic acid is required as a hydrogen donor.
[0023]
At the time of rainwater inflow, the organic acid concentration becomes thin and the organic matter that can be used by phosphorus accumulating bacteria decreases, so that sufficient phosphorus exhalation reaction will not be performed, and the subsequent excessive intake reaction of phosphorus will also be insufficient .
[0024]
Therefore, in order to make up for this, a carbon source necessary for phosphorus removal is secured by means similar to the case of nitrogen removal, or polyaluminum chloride, aluminum sulfate, iron sulfate stored in the flocculant storage tank 22 By injecting a flocculant such as aluminum phosphate and precipitating a phosphorus component in the form of aluminum phosphate or iron phosphate, phosphorus is removed.
[0025]
FIG. 8 is a block diagram showing a configuration example of a conventional sewage treatment plant water quality control device.
[0026]
In FIG. 8, the inflow water 1 flowing into the sewage treatment plant is an anaerobic tank of an aeration tank configured by a combination of an anaerobic tank 100 and an aerobic tank 101 provided with an aeration device 103 via a water pipe 120. After flowing into 100 and processing in the aeration tank, it is discharged as treated water 3 through the water pipe 121, the final sedimentation basin 102, and the water pipe 122.
[0027]
On the other hand, the untreated water in the aerobic tank 101 is returned to the anoxic tank 100 via the circulation pump 104.
[0028]
Further, the precipitated water in the final settling basin 102 is returned to the anoxic tank 100 via the water pipe 123 and the return pump 105.
[0029]
On the other hand, the aerobic tank 101 is provided with an ammonia nitrogen concentration meter 106 for measuring the ammonia nitrogen concentration, and the measured value 106a is output.
[0030]
Further, the control target value setter 108 sets a control target value 108a.
[0031]
Further, in the control unit 107, an operation amount 107 a for adjusting the aeration apparatus 103 based on a deviation between the measured value 106 a from the ammonia nitrogen concentration meter 106 and the control target value 108 a set by the control unit 107 is obtained. Obtained and given to the aeration apparatus 103.
[0032]
Thereby, control is performed so as to keep the ammonia concentration in the aeration tank constant.
[0033]
[Problems to be solved by the invention]
(A) However, as shown in FIG. 8, in the control in which the aeration air volume of the aeration apparatus 103 is adjusted by feedback (FB) control based on the ammonia nitrogen concentration after nitrification in the aerobic tank 101, In spite of large fluctuations in the amount of inflow water flowing into the sewage treatment plant, the water quality reaction by microorganisms in the aeration tank is relatively slow. Therefore, with such feedback control alone, the response of the water quality reaction to the change in the manipulated variable 107a is not achieved. There is a problem that it is slow and it is difficult to keep the quality of the treated water good.
[0034]
(B) Further, only by controlling the nitrification reaction, nitrite nitrogen and nitrate nitrogen remain, and a decrease in pH of discharged water and N resulting from denitrification reaction in the final sedimentation basin₂There is a problem of sludge levitation associated with gas generation.
[0035]
In the denitrification, the nitrification liquid is circulated in the anoxic tank 100 using the circulation pump 104 to perform denitrification. Conventionally, the circulation flow rate is a constant amount or a ratio control with respect to the inflow flow rate. However, there is a need for control for better denitrification.
[0036]
On the other hand, in order to perform denitrification satisfactorily, it is necessary to secure a carbon source. There is a problem that decreases.
[0037]
(C) Furthermore, ammonia component concentration meters such as ammonia nitrogen concentration meters, nitrate nitrogen concentration meters and total nitrogen concentration meters installed in sewage treatment plants, and phosphorus component concentration meters such as phosphoric acid concentration meters and total phosphorus meters Are likely to be contaminated by suspended components in sewage and often show abnormal values, so they are unstable, low-precision and difficult to use as control sensors.
[0038]
Further, even if the densitometer samples and filters, there is a problem in maintenance such as clogging of the sampling tube.
[0039]
(D) When the ratio of phosphorus component to organic component (C / P ratio) is secured to some extent, it is possible to remove phosphorus to some extent by biological dephosphorization alone, but the C / P ratio is small and phosphorus If the amount of organic matter that can be used by accumulating bacteria becomes smaller than the inflowing phosphorus, it will be difficult to remove phosphorus unless the carbon source is secured by some means or a flocculant such as polyaluminum chloride is injected. ing.
[0040]
At this time, how much the carbon source is injected is empirically performed, the cost due to the excessive injection of the flocculant, the outflow of polyaluminum chloride into the treated water, and the like are problems.
[0041]
The object of the present invention is to deteriorate the water quality balance such as the ratio (C / N ratio) of the nitrogen component and the organic substance component of the inflow water flowing into the sewage treatment plant and the ratio (C / P ratio) of the phosphorus component and the organic substance component. In such a case, it is an object of the present invention to provide a sewage treatment plant water quality control apparatus capable of always maintaining good quality of nitrogen and phosphorus in treated water discharged from the sewage treatment plant.
[0042]
[Means for Solving the Problems]
  To achieve the above objective,The present invention takes the following means.
[0044]
  ContractClaim1Departure corresponding toTomorrow,In a sewage treatment plant water quality control device that controls the quality of treated water discharged from a sewage treatment plant equipped with an aeration tank including an anaerobic tank and an aerobic tank,Phosphorus component concentration measuring means for measuring the phosphorus component concentration of the inflow water flowing into the sewage treatment plant, organic substance concentration measuring means for measuring the organic component concentration of the inflow water flowing into the sewage treatment plant, phosphorus component concentration measuring means, and C / P ratio for calculating the ratio (C / P ratio) between the phosphorus component and the organic component of the inflow water flowing into the sewage treatment plant based on the phosphorus component concentration and the organic component concentration measured by the organic component concentration measuring means A calculation means, a C / P ratio setting means for setting a reference C / P ratio as a reference, a reference C / P ratio set by the C / P ratio setting means, and a C calculated by the C / P ratio calculation means Based on the difference with the / P ratio,Precipitation water returned from the final sedimentation tank to the aeration tankReturn flow rate,Return water flow rate of return water returned from the sludge storage tank to the aeration tank,Aeration air volume, carbon source injection volume, coagulant injection volume, excess sludge flow rateFirstControl means for outputting an operation amount for controlling at least one of the sinking bypass valves.
[0045]
  Therefore, the claims1In the sewage treatment plant water quality control apparatus according to the invention, the C / P ratio of the inflow water flowing into the sewage treatment plant is calculated, and the return flow rate in the sewage treatment plant is calculated based on the difference from the reference C / P ratio. C / P ratio of inflow water flowing into sewage treatment plant by controlling at least one of aeration air volume, carbon source injection volume, coagulant injection volume, surplus sludge flow rate, return water flow rate, and primary sedimentation bypass valve Even when the water quality balance is deteriorated, it is possible to remove phosphorus by always maintaining good quality of phosphorus in the treated water discharged from the sewage treatment plant.
[0050]
  Claims2Departure corresponding toTomorrowSewage treatment plant water quality control that controls the quality of treated water discharged from a sewage treatment plant equipped with an anaerobic tank and an aerobic tank, or an aeration tank comprising a combination of an anaerobic tank, an anaerobic tank and an aerobic tank In the apparatus, the phosphorus component concentration measuring means for measuring the phosphorus component concentration in the anaerobic tank, the organic component concentration measuring means for measuring the organic component concentration of the inflow water flowing into the anaerobic tank, the phosphorus component concentration measuring means, and the organic component concentration C / P ratio calculating means for calculating a ratio (C / P ratio) between the phosphorus component and the organic substance component based on the phosphorus component concentration and the organic substance component concentration measured by the measuring means, and a reference C / P ratio as a reference Based on the difference between the C / P ratio setting means for setting, the reference C / P ratio set by the C / P ratio setting means and the C / P ratio calculated by the C / P ratio calculation means,Return flow rate of sediment water returned from the final sedimentation tank to the aeration tank, return water flow rate of return water returned from the sludge storage tank to the aeration tank,Aeration air volume, carbon source injection volume, excess sludge flow rateFirstControl means for outputting an operation amount for controlling at least one of the sinking bypass valves.
[0051]
  Therefore, the claims2In the sewage treatment plant water quality control device according to the invention, the C / P ratio between the phosphorus component and the organic matter component is calculated based on the phosphorus component concentration in the anaerobic tank and the organic component concentration of the inflow water flowing into the anaerobic tank. Calculate and control at least one of the return flow rate, aeration air flow rate, carbon source injection rate, surplus sludge flow rate, return water flow rate, and primary sediment bypass valve at the sewage treatment plant based on the difference from the standard C / P ratio. By doing so, even when the water quality balance of the C / P ratio of the inflow water flowing into the sewage treatment plant is deteriorated, the quality of phosphorus in the treated water discharged from the sewage treatment plant is always maintained well, Phosphorus removal can be performed. It can also be applied to cases where phosphorus component concentration measuring means and organic component concentration measuring means are not installed in the inflow part of the sewage treatment plant, and by controlling the concentration in the aeration tank part, controllability can be improved. It can be made even better.
[0056]
  Claims3Departure corresponding toTomorrowThe above claims1 orClaim2In any one itemCorresponding inventionIn the sewage treatment plant water quality control device, a concentration meter that measures either phosphoric acid phosphorus concentration or total phosphorus concentration is used as the phosphorus component concentration measuring means, and biochemical oxygen demand ( BOD), chemical oxygen demand (CODMn, CODcr), and a total organic carbon content (TOC) are measured.
[0057]
  Therefore, the claims3In the sewage treatment plant water quality control device according to the invention, the phosphorous component concentration measuring means uses a concentration meter that measures phosphoric acid phosphorus concentration and total phosphorus concentration, and the organic component concentration measuring means uses biochemical oxygen demand. The net C / P ratio can be calculated by using a densitometer that measures quantity (BOD), chemical oxygen demand (CODMn, CODcr), and total organic carbon (TOC).
[0060]
  Meanwhile, claims4In the invention corresponding to the above, the above claims 1 to3In the sewage treatment plant water quality control device of the invention corresponding to any one of the above, the flow rate of the inflow water flowing into the sewage treatment plant,Component concentration measurement meansandHands measuring organic component concentrationIn stepsBased on the inflow water quality database that stores the time series data of the water quality component measurement values and the water quality test results by manual analysis, and the inflow water phosphorus flowing into the sewage treatment plant based on the time series data stored in the inflow water quality database. Component concentration,as well asOrganic component concentrationDegreeInflow water quality prediction means for predicting the inflow water quality.TariComponent concentration, organic component concentration, CThe / P ratio is calculated.
[0061]
  Therefore, the claims4In the sewage treatment plant water quality control device corresponding to the Inflow water flowing intoNoComponent concentration,as well asOrganic component concentrationDegreePredict and use the predicted value, CBy calculating the / P ratio,If it is difficult to install organic component concentration measuring means or organic component concentration measuring meansIsEven when the component concentration measuring means and the organic component concentration measuring means fail, the control can be sufficiently performed.
[0062]
  Claims5In the invention corresponding to the above, the above claims 1 to4In the sewage treatment plant water quality control device according to any one of the inventions,Nitrogen component concentration measuring means for measuring the nitrogen component concentration of inflow water flowing into the sewage treatment plant, organic substance concentration measuring means for measuring the organic component concentration of inflow water flowing into the sewage treatment plant, nitrogen component concentration measuring means, C / N ratio for calculating the ratio (C / N ratio) between the nitrogen component and the organic component of the inflow water flowing into the sewage treatment plant based on the nitrogen component concentration and the organic component concentration measured by the organic component concentration measuring means. Calculation means, reference C / N ratio setting means for setting a reference C / N ratio as a reference,Flow rate measuring means for measuring the flow rate of inflow water flowing into the sewage treatment plantWhenThefurtherThe control means includes a flow rate value measured by the flow rate measurement means, a reference C / N ratio set by the reference C / N ratio setting means, and a C / N ratio calculated by the C / N ratio calculation means. Based on the difference and the difference between the reference C / P ratio set by the C / P ratio setting means and the C / P ratio calculated by the C / P ratio calculation means,Circulation flow rate of non-treated water circulated in the aeration tank, return flow rate of sediment water returned from the final sedimentation tank to the aeration tank, return water flow rate of return water returned from the sludge storage tank to the aeration tank,Aeration air volume, carbon source injection volume, excess sludge flow rateFirstAn operation amount for controlling at least one of the sinking bypass valves is output.
[0063]
  Therefore, the claims5In the sewage treatment plant water quality control device according to the invention, the flow rate measuring means for measuring the flow rate of the inflow water flowing into the sewage treatment plant is used, and the flow rate measurement value by the flow rate measurement means, the reference C / N ratio and C / Based on the difference between the N ratio and the difference between the reference C / P ratio and the C / P ratio, the circulation flow rate, return flow rate, aeration air amount, carbon source injection amount, surplus sludge flow rate, return water flow rate in the sewage treatment plant, By controlling at least one of the primary sedimentation bypass valves, the controllability is always improved even when the quality of the treated water changes due to the size of the influent water flowing into the sewage treatment plant. Can be maintained.
[0066]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0067]
(First embodiment)
FIG. 1 is a block diagram showing a configuration example of a sewage treatment plant water quality control apparatus according to the present embodiment. The same parts as those in FIG. State.
[0068]
That is, as shown in FIG. 1, the sewage treatment plant water quality control device according to the present embodiment includes a TOC meter 4 as an organic component concentration measuring means and an ammonia concentration meter 5 as a nitrogen component concentration measuring means as shown in FIG. A C / N ratio calculation unit 6, a reference C / N ratio setting unit 7, and a control unit 8 are added.
[0069]
Note that the valve 24, the water pipe 59, and the initial settling bypass valve 23 in FIG. 7 are not shown in FIG.
[0070]
The TOC meter 4 is installed in the water pipe 51, and measures the total organic carbon amount (TOC) 4a that is the organic component concentration of the inflow water 1 flowing into the sewage treatment plant.
[0071]
The ammonia concentration meter 5 is installed in the same water pipe 51 and measures the total nitrogen concentration 5a which is the nitrogen component concentration of the inflow water 1 flowing into the sewage treatment plant.
[0072]
The C / N ratio calculation unit 6 is configured to calculate the nitrogen component and the organic component of the influent 1 flowing into the sewage treatment plant based on the total organic carbon amount 4a and the total nitrogen concentration 5a measured by the TOC meter 4 and the ammonia concentration meter 5. The ratio (C / N ratio) 6a is calculated.
[0073]
The reference C / N ratio setting unit 7 sets a reference C / N ratio 7a as a reference.
[0074]
Based on the difference between the reference C / N ratio 7a set by the reference C / N ratio setter 7 and the C / N ratio 6a calculated by the C / N ratio calculation unit 6, the control unit 8 The operation amount 8a for adjusting the flow rate of the carbon injection pump 19 is output.
[0075]
Next, the operation of the sewage treatment plant water quality control apparatus according to this embodiment configured as described above will be described.
[0076]
In FIG. 1, the total organic carbon amount (TOC) 4 a that is a measured value of the TOC meter 4 mounted on the water pipe 51 that flows into the aeration tank from the first sedimentation tank 2 and the measured value of the total nitrogen meter 5. The total nitrogen concentration 5a is input to the C / N ratio calculation unit 6 via the signal lines 4a and 5a, and the C / N ratio is calculated based on these.
[0077]
An arithmetic expression in this case is expressed by, for example, the following expression (1.1).
[0078]
[Expression 1]

[0079]
P_CN: C / N ratio at time t
C_TOC: TOC concentration of influent water, C_TN: Total nitrogen concentration of influent
The C / N ratio calculated by the above equation (1.1) is input to the control unit 8 through the signal line 6a.
[0080]
On the other hand, the reference C / N ratio setter 7 sets the reference C / N ratio.
[0081]
In the control unit 8, based on the deviation between the C / N ratio calculated by the C / N ratio calculation unit 6 and the reference C / N ratio, the carbon source injection amount target value is expressed by, for example, the following formula (1.2) The carbon source injection amount is adjusted so that the carbon source injection amount target value is obtained.
[0082]
[Expression 2]

[0083]
SVQ_{carbon, t}: Carbon source injection amount target value at time t
P_{CN, t}: C / N ratio at time t
P_Cnbase: Standard C / N ratio for efficient nitrogen removal
Q_in: Sewage treatment plant inflow rate
C_carbonTOC: TOC concentration of carbon source
C_{T-Nin, t}: TN concentration of influent
On the other hand, the reference C / N ratio P set by the reference C / N ratio setter 7_CnbaseThe value of varies depending on the target sewage treatment plant, but in order to efficiently remove nitrogen, it is necessary to secure 3 to 4 as the BOD / t-N ratio. It is preferable to set a value of about 4 to 6 in consideration of the ratio.
[0084]
Carbon source TOC concentration C_carbonTOCCan be easily determined if the carbon source used (methanol, ethanol, acetic acid, waste acetic acid, glucose etc) and the concentration of the solution are known.
[0085]
The carbon source injection amount is adjusted according to the carbon source injection amount target value calculated by the above equation (1.2).
[0086]
The present sewage treatment plant water quality control device can inject the required amount of carbon source only when the C / N ratio is lowered, that is, when the amount of organic matter required for efficient nitrogen removal is insufficient. Nitrogen removal without excessive injection of nitrogen can be performed.
[0087]
As described above, in the sewage treatment plant water quality control apparatus according to the present embodiment, the following effects can be obtained.
[0088]
(A) Since the carbon source injection pump 19 is used as a control target, the C / N ratio corresponding to the injection amount can be easily calculated, and without excessive carbon source injection, It becomes possible to maintain a value equal to or higher than the C / N ratio required for efficient nitrogen removal.
[0089]
(B) Since the TOC meter 4 is used as a sensor for measuring organic components and the total nitrogen meter 5 is used as a sensor for measuring nitrogen components, it is possible to calculate the net organic matter and nitrogen ratio.
[0090]
(C) The reference C / N ratio P is set by the reference C / N ratio setter 7._CnbaseSince all parameters can be calculated as long as is set, there is no need for parameter adjustment.
[0091]
(D) Since the total nitrogen meter 5 and the TOC meter 4 are arranged in the water pipe 51 after first passing through the settling basin 2, there is less possibility of sensor value abnormality due to dirt as compared with the case where it is arranged in the water pipe 50. In addition, the net C / N ratio flowing into the aeration tank can be calculated.
[0092]
(Modification 1)
The nitrogen component concentration meter 5 and the organic component concentration meter 4 in FIG. 1 may be attached to the water pipe 50 as attachment positions.
[0093]
Moreover, if it is a front | former stage part of an aeration tank, such as the first sedimentation tank 2, an inflow tank, a sand basin, a pump well, etc., it can be used in any position.
[0094]
(Modification 2)
As the organic component concentration meter 4 in FIG. 1, a BOD meter or a COD meter may be used instead of the TOC meter.
[0095]
Further, as the nitrogen concentration meter 5, even if it is not a total nitrogen meter, an ammonia nitrogen concentration meter is used because most of the nitrogen component of the influent 1 flowing into the sewage treatment plant is ammonia nitrogen. It may be.
[0096]
(Modification 3)
As the nitrogen component concentration meter 5 in FIG. 1, a nitrate nitrogen meter attached in the anoxic tank 11 may be used.
[0097]
(Modification 4)
Examples of the carbon source include methanol, ethanol, acetic acid, waste acetic acid, glucose and the like.
[0098]
Moreover, you may make it use the extraction sludge of the first sedimentation basin 2 of FIG. 1, and what fermented it.
[0099]
(Modification 5)
As the operation amount 8a calculated by the control unit 8 in FIG. 1, in addition to the carbon source injection amount, the circulation flow rate, the return flow rate, the aeration air amount, the carbon source injection amount, the surplus sludge flow rate, the return water flow rate, the initial sedimentation bypass valve Either may be sufficient.
[0100]
For example, when the operation amount 8a calculated by the control unit 8 is a circulation flow rate, the target value is calculated by an arithmetic expression as shown in the following expression (1.3), for example.
[0101]
[Equation 3]

[0102]
SVQ_{cir, t}: Carbon source injection amount target value at time t
P_{CN, t}: C / N ratio at time t
P_Cnbase: C / N ratio for efficient nitrogen removal
Q0: Constant
K: Proportional constant
The constant of Q0 may be a constant flow rate or a target value for ratio control with respect to the inflow flow rate.
[0103]
Thereby, when the C / N ratio is insufficient, the circulating flow rate is controlled to increase, and when the C / N ratio is sufficient, the circulating flow rate is controlled to decrease, so that nitrogen removal can be performed efficiently. .
[0104]
(Modification 6)
The operation amount 8a calculated by the control unit 8 of FIG. 1 is not limited to the one described above, but may be a plurality of operations.
[0105]
For example, when the carbon source injection amount and the return water flow rate are selected as the operation amount 8 a calculated by the control unit 8, the C / N ratio is higher than the value set by the reference C / N ratio setting unit 7. When it is large, the return water flow rate is controlled in the form as shown in the following formula (1.4), and when the C / N ratio is smaller than the value set by the reference C / N ratio setter 7 Is controlled such that the carbon source injection amount is as shown in the equation (1.2).
[0106]
In this way, switching control may be performed.
[0107]
That is, the return water returned from the sludge storage tank 20 has a higher nitrogen load and a lower C / N ratio than the inflow water flowing from the sewer pipe. Acts in the direction of decreasing the ratio.
[0108]
When the C / N ratio is large, the control target value is calculated so that the return water amount increases.
[0109]
Further, when the C / N ratio becomes smaller, the control target value is calculated so that the return water amount becomes smaller.
[0110]
[Expression 4]

[0111]
SVQ_{cir, t}: Carbon source injection amount target value at time t
P_CN: C / N ratio at time t
P_Cnbase: Standard C / N ratio
T_I: Integration time
Q0: Constant
K: Proportional constant
When the C / N ratio is smaller than the value set by the reference C / N ratio setting unit 7 and the carbon source is insufficient, the return water amount is directed toward zero and P_{CN, t}<P_CnbaseThen it becomes zero.
[0112]
On the other hand, P_{CN, t}<P_CnbaseIn this case, the carbon source injection amount tends to increase as described above.
[0113]
Further, instead of the switching control as described above, two or more operation amounts may be controlled simultaneously.
[0114]
(Modification 7)
The target process may be applied to any of the following water treatment processes.
[0115]
Standard activated sludge method
A₂O method (anaerobic-anoxic-aerobic method)
AO method (anaerobic-aerobic method)
Nitrification endogenous denitrification method
Circulating nitrification denitrification method
OD method
Step injection method
Batch activated sludge process
Intermittent aeration
Activated sludge method with carrier
Carrier input A₂O method
Carrier input AO method
Nitrification endogenous denitrification method
Circulating nitrification denitrification method with carrier
Carrier loading OD method
Carrier injection step injection method
Batch loading activated sludge method
Intermittent aeration method with carrier
Coagulant injection type activated sludge method
Flocculant injection A₂O method
Flocculant injection AO method
Flocculant injection nitrification endogenous denitrification method
Coagulant injection circulation nitrification denitrification method
Flocculant injection OD method
Flocculant injection step injection method
Coagulant injection batch activated sludge method
Flocculant injection intermittent aeration method
Membrane separation activated sludge method
Membrane separation type A₂O method
Membrane separation type AO method
Membrane separation type nitrification endogenous denitrification method
Membrane separation type circulation nitrification denitrification method
Membrane separation OD method
Membrane separation type step injection method
Membrane separation type batch activated sludge method
Membrane separation type intermittent aeration method
In addition to the above, various types of A, such as carrier loading, coagulant combined process, or AOAO method, etc.₂You may make it use for any modification of O method.
[0116]
(Modification 8)
The operation amount 8a calculated by the control unit 8 of FIG. 1 is as follows in consideration of the time lag until the C / N ratio of the influent water 1 flowing into the sewage treatment plant is calculated and the flow into the aeration tank. It is good also as what is shown to Formula (1.5).
[0117]
[Equation 5]

[0118]
SVQ_{carbon, t}: Carbon source injection amount target value at time t
P_CN: C / N ratio at time t
P_Cnbase: Standard C / N ratio
Q_{in, t- Δ t}: Sewage treatment plant inflow rate at time t-Δt
C_carbonTOC: TOC concentration of carbon source
C_{T-Nin, t}: Total nitrogen concentration of influent at time t-Δt
(Modification 9)
Correlation between the ultraviolet ray (UV) intensity measured by a UV meter that measures the ultraviolet ray (UV) intensity and the organic substance component concentration, even if the organic substance component concentration of the influent 1 flowing into the sewage treatment plant is not directly measured. Therefore, a conversion value obtained by obtaining the organic component concentration of the influent water 1 flowing into the sewage treatment plant may be used.
[0119]
For example, it is said that the chemical oxygen demand (COD) value is generally highly correlated with the UV value, and the COD value can be estimated by the following equation (1.6). it can.
[0120]
[Formula 6]

[0121]
C_COD: COD estimate
C_UV: UV measurement value
a, b: constant
As a result, even in a sewage treatment plant where an organic component concentration meter such as a COD meter is not installed, the measurement value of the UV meter, which is a more stable sensor, is less affected by contamination of the water to be treated. Thus, control can be performed.
[0122]
(Modification 10)
The operation amount 8a output calculated by the control unit 8 in FIG._{CN, t}-P_CNbase) As long as it is based on the deviation.
[0123]
For example, the logarithm log (P_{CN, t}-P_CNbase), An exponential function exp (P_{CN, t}-P_CNbase), Power (P_{CN, t}-P_CNbase)ⁿIt is also possible to use something that is proportional to or a combination of these.
[0124]
(Modification 11)
The C / N ratio is not calculated from the measured values of the organic component concentration meter 4 and the nitrogen component concentration meter 5, but is calculated using predicted values predicted using past inflow water quality patterns. It may be.
[0125]
(Modification 12)
What correct | amends the ratio of the flow rate ratio control with respect to the inflow flow rate of the inflowing water 1 which flows in into a sewage treatment plant, and correct | amends the control target value of DO control.
[0126]
(Modification 13)
In addition to the C / N ratio calculation unit 6 of FIG. 1, a C / P ratio calculation unit is provided, and based on the C / N ratio and C / P ratio calculated by these, the circulation flow rate, the return flow rate, the aeration air volume, At least one of the carbon source injection amount, the flocculant injection amount, the excess sludge flow rate, and the return water flow rate may be adjusted.
[0127]
(Modification 14)
Feedback (FB) using a water quality sensor attached to a part where biological water treatment is almost completed, such as the rear part of the aerobic tank 12 in FIG. 1, the water pipe 52, the final sedimentation tank 13, the water pipe 60, etc. The control amount may be corrected by the control.
[0128]
(Second Embodiment)
FIG. 2 is a block diagram showing an example of the configuration of the sewage treatment plant water quality control apparatus according to the present embodiment. The same parts as those in FIG. State.
[0129]
That is, as shown in FIG. 2, the sewage treatment plant water quality control apparatus according to the present embodiment includes a TOC meter 4 as an organic component concentration measuring means and a total phosphorus concentration meter as a phosphorus component concentration measuring means in FIG. 25, a C / P ratio calculation unit 6 ', a reference C / P ratio setter 7', and a control unit 8 are added.
[0130]
Note that the valve 24, the water pipe 59, and the initial sediment bypass valve 23 in FIG. 7 are not shown in FIG.
[0131]
The TOC meter 4 is installed in the water pipe 51, and measures the total organic carbon amount (TOC) 4a that is the organic component concentration of the inflow water 1 flowing into the sewage treatment plant.
[0132]
The total phosphorus concentration meter 25 is installed in the same water pipe 51 and measures the total phosphorus concentration 25a which is the phosphorus component concentration of the inflow water 1 flowing into the sewage treatment plant.
[0133]
The C / P ratio calculation unit 6 'calculates the phosphorus component of the influent 1 flowing into the sewage treatment plant based on the total organic carbon amount 4a and the total phosphorus concentration 25a measured by the TOC meter 4 and the total phosphorus concentration meter 25. The ratio (C / P ratio) 6′a with the organic component is calculated.
[0134]
The reference C / P ratio setting unit 7 'sets a reference C / P ratio 7'a as a reference.
[0135]
The control unit 8 determines the difference between the reference C / P ratio 7'a set by the reference C / P ratio setter 7 'and the C / P ratio 6'a calculated by the C / P ratio calculation unit 6'. Based on this, an operation amount 8a for adjusting the flow rate of the PAC injection pump 16 in the sewage treatment plant is output.
[0136]
Next, the operation of the sewage treatment plant water quality control apparatus according to this embodiment configured as described above will be described.
[0137]
In FIG. 2, the total organic carbon amount (TOC) 4 a that is a measurement value of the TOC meter 4 mounted on the water pipe 51 that flows into the aeration tank from the first settling basin 2 and the total measurement value of the total phosphorus meter 25. The phosphorus concentration 25a is input to the C / P ratio calculation unit 6 'via the signal lines 4a and 25a, and the C / P ratio is calculated based on these.
[0138]
An arithmetic expression in this case is expressed by, for example, the following expression (2.1).
[0139]
[Expression 7]

[0140]
P_{CP, t}: C / P ratio at time t
C_TOC: TOC concentration of influent water,
C_TP: Total phosphorus concentration of influent
The C / P ratio calculated by the above equation (2.1) is input to the control unit 8 through the signal line 6a ′.
[0141]
On the other hand, the reference C / P ratio is set by the reference C / P ratio setter 7 '.
[0142]
In the control unit 8, based on the deviation between the C / P ratio calculated by the C / P ratio calculation unit 6 ′ and the reference C / P ratio, the PAC injection amount target value is expressed by, for example, the following formula (2.2) The PAC flow rate is adjusted so that the PAC injection amount target value is obtained by the calculation shown in FIG.
[0143]
[Equation 8]

[0144]
SVQ_{PAC, t}: PAC injection target value at time t
P_CP: C / P ratio at time t
P_Cnbase: Standard C / P ratio
Q0: Constant
K: Proportional constant
The constant of Q0 may be a constant flow rate or a target value for ratio control with respect to the inflow flow rate.
[0145]
Reference C / P ratio P set by reference C / P ratio setter 7 '_CPbaseThe value of varies depending on the target sewage treatment plant, but in order to efficiently remove phosphorus nitrogen simultaneously, it is necessary to secure a BOD / TP ratio of about 25. Considering the / TOC ratio, it is preferable to set a value of about 30 to 45.
[0146]
When the C / P ratio is small by this sewage treatment plant water quality control device, the biological phosphorus removal efficiency decreases, so that the PAC injection amount increases and conversely the C / P ratio is large. In this case, the PAC injection amount is reduced.
[0147]
As described above, in the sewage treatment plant water quality control apparatus according to the present embodiment, the following effects can be obtained.
[0148]
(A) Since the PAC infusion pump 16 is used as a control target, even if the C / P ratio is low and biological phosphorus removal is difficult, phosphorus removal can be performed without deteriorating the phosphorus concentration of the discharged water quality. Can be performed.
[0149]
(B) Since the TOC meter 4 is used as the sensor for measuring the organic component and the total phosphorus meter 25 is used as the sensor for measuring the phosphorus component, the net organic matter and the phosphorus ratio can be calculated.
[0150]
(C) The reference C / P ratio P is set by the reference C / P ratio setter 7 '._CPbaseAs long as is set, there are only two parameters, K and Q0, and parameter adjustment can be performed relatively easily.
[0151]
(D) Since the total phosphorus meter 25 and the TOC meter 4 are arranged in the water pipe 51 after first passing through the settling basin 2, the possibility of abnormal sensor values due to dirt is less than in the case of arranging the water pipe 50. In addition, it is possible to calculate the net C / P ratio flowing into the aeration tank.
[0152]
(Modification 1)
The phosphorus component concentration meter 25 and the organic component concentration meter 4 in FIG. 2 may be attached to the water pipe 50 as attachment positions.
[0153]
Moreover, if it is a front | former stage part of an aeration tank, such as the first sedimentation tank 2, an inflow tank, a sand basin, a pump well, etc., it can be used in any position.
[0154]
(Modification 2)
As the organic component concentration meter 4 in FIG. 2, not only a TOC meter but also a BOD meter or a COD meter may be used.
[0155]
Further, even if the phosphorus component concentration meter 25 is not a total phosphorus meter, since most of the phosphorus component of the influent 1 flowing into the sewage treatment plant is phosphoric acid phosphorus, a phosphoric acid phosphorus concentration meter is used. It may be.
[0156]
(Modification 3)
As the total phosphorus meter 25 in FIG. 2, a phosphoric acid phosphorus meter attached in the anaerobic tank 10 may be used.
[0157]
(Modification 4)
The operation amount 8a calculated by the control unit 8 in FIG. 2 may be any one of a return flow rate, an aeration air amount, a carbon source injection amount, an excess sludge flow rate, and a return water flow rate in addition to the PAC (flocculant) injection amount. Good.
[0158]
(Modification 5)
The operation amount 8a calculated by the control unit 8 in FIG. 2 is not limited to controlling only one described above, but may be a plurality of operations.
[0159]
(Modification 6)
The target process may be applied to any of the water treatment processes as described above.
[0160]
Also, various types of A such as carrier loading, coagulant combined type process, AOAO method, etc.₂You may make it use for any modification of O method.
[0161]
(Modification 7)
As the operation amount 8a calculated by the control unit 8 in FIG. 2, the time point until the C / P ratio of the influent water 1 flowing into the sewage treatment plant is calculated and the time lag until it flows into the aeration tank may be considered. Good.
[0162]
(Modification 8)
Correlation between the ultraviolet ray (UV) intensity measured by a UV meter that measures the ultraviolet ray (UV) intensity and the organic substance component concentration, even if the organic substance component concentration of the influent 1 flowing into the sewage treatment plant is not directly measured. Therefore, a conversion value obtained by obtaining the organic component concentration of the influent water 1 flowing into the sewage treatment plant may be used.
[0163]
(Modification 9)
The C / P ratio may not be calculated from the measured values of the organic substance concentration meter and the nitrogen component concentration meter, but may be a prediction value predicted by a method described later. (Invention of Claim 10)
(Modification 10)
The output of the operation amount 8a calculated by the control unit 8 in FIG._{CN, t}-P_CNbaseEven if it is not linearly proportional to)), it may be anything based on deviation.
[0164]
For example, the logarithm log (P_{CN, t}-P_CNbase), An exponential function exp (P_{CN, t}-P_CNbase), Power (P_{CN, t}-P_CNbase)ⁿIt is also possible to use something that is proportional to or a combination of these.
[0165]
(Modification 11)
The C / P ratio is not calculated from the measured values of the organic substance concentration meter 4 and the phosphorus component concentration meter 25, but is calculated using a predicted value predicted using a past influent water quality pattern or the like. It may be what was done.
[0166]
(Modification 12)
What correct | amends the ratio of the flow rate ratio control with respect to the inflow flow rate of the inflowing water 1 which flows in into a sewage treatment plant, and correct | amends the control target value of DO control.
[0167]
(Modification 13)
In addition to the C / P ratio calculation unit 6 'of FIG. 2, a C / N ratio calculation unit is provided, and based on the C / N ratio and C / P ratio calculated by these, the circulation flow rate, the return flow rate, and the aeration air volume The carbon source injection amount, the flocculant injection amount, the excess sludge flow rate, and the return water flow rate may be adjusted.
[0168]
(Modification 14)
Feedback (FB) using a water quality sensor attached to a portion where biological water treatment is almost completed, such as the rear stage of the aerobic tank 12, the water pipe 52, the final sedimentation tank 13, the water pipe 60, etc. The control amount may be corrected by the control.
[0169]
(Third embodiment)
FIG. 3 is a block diagram showing a configuration example of the sewage treatment plant water quality control apparatus according to the present embodiment. The same parts as those in FIG. State.
[0170]
That is, as shown in FIG. 3, the sewage treatment plant water quality control apparatus according to the present embodiment includes, in FIG. 4, a UV meter 30 that is an ultraviolet ray measuring means, a flow meter 31 that is a flow rate measuring means, and an NH._FourTotal meter 32, TN meter 33 as nitrogen component concentration measuring means, TP meter 34 as phosphorus component concentration measuring means, influent water quality database 26, weather information prediction unit 27, influent water quality pattern database 28 An inflow water quality prediction unit 29, a reference C / N ratio C / P ratio setter 7 ″, a UV → BOD converter 37, a C / N ratio C / P ratio calculation unit 6 ″, and an inflow ratio setter. 38, a control unit 8, a treated water quality determination unit 36, and a control correction unit 35 are added.
[0171]
Note that the illustration of the valve 24, the water pipe 59, the initial sediment bypass valve 23, the carbon source storage tank 21, the carbon source injection pump 19, and the water pipe 57 in FIG. 7 is omitted in FIG.
[0172]
The UV meter 30 is installed in the water pipe 51 and measures the ultraviolet (UV) intensity of the inflow water 1 flowing into the sewage treatment plant.
[0173]
The flow meter 31 is installed in the same water pipe 51 and measures the flow rate of the influent water 1 flowing into the sewage treatment plant.
[0174]
NH_FourThe total 32 is installed in the aerobic tank 12 and measures the ammonia concentration in the aerobic tank 12.
[0175]
The TN meter 33 is installed in the water pipe 61 and measures the total nitrogen concentration of the treated water 3.
[0176]
The TP meter 34 is installed in the water pipe 61 and measures the total phosphorus concentration of the treated water 3.
[0177]
The influent water quality database 26 includes ultraviolet (UV) intensity measured by the UV meter 30, NH_FourAmmonia concentration measured by meter 32, total nitrogen concentration measured by TN meter 33, total phosphorus concentration measured by TP meter 34, flow rate measured by flow meter 31, and daily water quality test Each time series data of the water quality test result by a certain manual analysis is stored.
[0178]
The weather information prediction unit 27 predicts weather information.
[0179]
The inflow water quality pattern database 28 creates and stores an inflow water quality pattern based on the data accumulated in the inflow water quality database 26.
[0180]
The inflow water quality prediction unit 29 is based on the TN water quality pattern stored in the inflow water quality pattern database 28 and the meteorological information predicted by the meteorological information prediction unit 272, and the inflow water flowing into the sewage treatment plant. Predict at least one of nitrogen component concentration, phosphorus component concentration, and organic component concentration.
[0181]
The reference C / N ratio C / P ratio setter 7 ″ sets a reference C / N ratio and a reference C / P ratio.
[0182]
The UV → BOD converter 37 converts the ultraviolet (UV) intensity measured by the UV meter 30 into a biochemical oxygen demand (BOD).
[0183]
The C / N ratio C / P ratio calculation unit 6 ″ is set by the nitrogen component concentration, the phosphorus component concentration, the organic component concentration predicted by the influent water quality prediction unit 29, and the N ratio C / P ratio reference setting unit 7 ″. Based on the reference C / N ratio, the reference C / P ratio, and the BOD converted by the UV → BOD converter 37, the C / N ratio and the C / P ratio are calculated.
[0184]
The inflow rate setting unit 38 sets the ratio of the aeration air volume, the circulation flow rate, and the PAC injection flow rate with respect to the flow rate of the influent water 1 flowing into the sewage treatment plant.
[0185]
The control unit 8 includes the C / N ratio calculated by the C / N ratio C / P ratio calculation unit 6 ″, the reference C set by the C / P ratio and the C / N ratio C / P ratio reference setting unit 7 ″. Based on the deviations of the / N ratio and the reference C / P ratio, the operation amounts for adjusting the aeration apparatus 9, the circulation pump 14, and the PAC injection pump 16 are output.
[0186]
The treated water quality determination unit 36 is NH_FourBased on the ammonia concentration measured by the meter 32, the total nitrogen concentration measured by the TN meter 33, and the total phosphorus concentration measured by the TP meter 34, the water quality state of the treated water 3 is determined. .
[0187]
The control correction unit 35 is based on the difference between the water quality state of the treated water 3 determined by the treated water quality determination unit 36 and the preset target value of the water quality component, and the aeration apparatus 9 output from the control unit 8; The operation amounts for the circulation pump 14 and the PAC injection pump 16 are corrected.
[0188]
Next, the operation of the sewage treatment plant water quality control apparatus according to the present embodiment configured as described above will be described with reference to the relational diagrams shown in FIGS.
[0189]
In FIG. 3, the UV intensity, which is a measurement value of the UV meter 30 attached on the water pipe 51 connected to the anaerobic tank 10 from the first sedimentation basin 2, is converted into a BOD value by the UV → BOD converter 37, It is input to the C / N ratio C / P ratio calculation unit 6 ″ via a line.
[0190]
The nitrogen component concentration and the phosphorus component concentration, which are the influent quality of the influent 1 flowing into the sewage treatment plant, are predicted by the following method.
[0191]
The inflow water quality database 26 holds time-series data of water quality measured by daily water quality tests, flow rate measurement values by the flow meter 31, and time-series data of UV measurement values by the UV meter 30.
[0192]
[Table 1]

[0193]
Inflow water quality pattern database 28 stores inflow water quality patterns for each day event such as weather, rainfall, rainfall duration, rainfall intensity, temperature, weather information, season, weekdays, Sundays, and the like.
[0194]
This is created from data stored in the influent water quality database 26, but this influent water quality pattern can be freely changed by the operator of the sewage treatment plant.
[0195]
For example, FIG. 4 is a diagram illustrating an inflow TN fluctuation pattern on weekdays, summer, and sunny days.
[0196]
The water quality pattern of TN has a peak in the morning as shown in FIG.
[0197]
Similarly, the TP water quality pattern has a peak in the morning.
[0198]
In FIG. 4, the circles indicate data stored in the influent water quality database 26.
[0199]
The inflow water quality prediction unit 29 selects a similar day based on the day event of the day and the weather information predicted by the weather information prediction unit 27, and selects the TN water quality pattern of the day from the water quality pattern database 28.
[0200]
In this case, if TN is measured at a certain time of the day and the value is input to the influent water quality database 26, the water quality of different TN is obtained based on the data, for example, as shown in FIG. A pattern is selected and the daily fluctuation pattern is corrected.
[0201]
In addition, the daily variation pattern is updated from time to time by searching again for similar days based on data accumulated in the influent water quality database 26 such as measurement values of the flow meter 31 and measurement values of the UV meter 30.
[0202]
The TN concentration and the TP concentration predicted by the inflow water quality prediction unit 29 are input to the C / N ratio C / P ratio calculation unit 6 ″ via a signal line.
[0203]
The C / N ratio C / P ratio calculation unit 6 ″ calculates a C / N ratio and a C / P ratio based on the following formulas (3.1) and (3.2), respectively.
[0204]
[Equation 9]

[0205]
P_{CN, t}: C / N ratio at time t
C_BOD: Inflow water BOD concentration conversion value,
C_TN: Inflow water total nitrogen concentration predicted value
[Expression 10]

[0206]
P_{CP, t}: C / P ratio at time t
C_BOD: Inflow water BOD concentration conversion value,
C_TP: Predicted total phosphorus concentration in influent
On the other hand, the ratios Rblow, Rcir, and Rpac of the aeration air amount, the circulation flow rate, and the PAC injection flow rate with respect to the inflow rate are set by the inflow rate setting unit 38, respectively.
[0207]
Then, the C / N ratio and C / P ratio calculated by the C / N ratio C / P ratio calculating unit 6 ″ and the reference C / N ratio C / P ratio setter 7 ″ are set as the reference C / N ratio. Based on the respective deviations between the N ratio and the reference C / P ratio, the ratio of the circulation flow rate and the PAC injection amount to the inflow rate is corrected.
[0208]
## EQU11 ##

[0209]
SVQ_{blow, t}: Aeration air flow target value
SVQ_{cir, t}: Circulation flow target value
SVQ_{pac, t}: PAC flow rate target value
Q_{in, t}: Inflow flow rate at time t
P_CNbase: Standard C / N ratio
P_CPbase: Standard C / P ratio
Sblow, Scir, Spac: Control correction amount
K1, K2: Constant
[0210]
[Expression 12]

[0211]
C_{NH4, t}: Ammonia nitrogen concentration at time t
C_{TN, t}: Total nitrogen concentration at time t
C_{TP, t}: Total phosphorus concentration at time t
K3, K4, K5: Constant
According to the above formulas (3.3) to (3.5), when the C / N ratio is insufficient, the circulation flow rate is increased, and when the C / P ratio is insufficient, the PAC injection amount is increased. .
[0212]
The control correction amounts (Sblow, Scir, Spac) are calculated by the following equations (3.6) to (3.8), respectively.
[0213]
Count value of TN meter 33 attached to pipe 60 after passing through final sedimentation tank 13, count value of TP meter 34, and NH_FourWhen the treated water quality determination unit 36 that determines the water quality state of the treated water 3 based on the count value of the total 32 determines that the treatment of TN and TP tends to deteriorate, correction is applied. .
[0214]
That is, for example, as shown in FIGS. 6A to 6C, (1) when the measured values of the TN meter 33 and the TP meter 34 are continuously increasing (FIG. 6A). (2) When the measured values of the TN meter 33 and the TP meter 34 are equal to or greater than the processing deterioration judgment value and a predetermined time has elapsed (FIG. 6B), (3) the TN meter 33, T- It is determined that the water quality of the treated water 3 has deteriorated, for example, when there is a sudden increase in concentration within a certain time width measured by the P meter 34 (FIG. 6C).
[0215]
For this reason, when the treated water quality determination unit 36 determines that the treated water has deteriorated, the control amount is corrected by the following logic.
[0216]
(1) The treated water TN deteriorates and NH in the aerobic tank 12_FourIf the measured value by the meter 32 is higher than a certain reference value, the aeration air volume is corrected by the above equation (3.6), for example.
[0217]
(2) The treated water TN deteriorates, the measured value of the treated water TN meter 33 and the NH in the aerobic tank 12_FourWhen the difference from the measured value by the total 32 is a certain value or more, it is determined that the denitrification process is defective, and the circulation flow rate is corrected by, for example, the above equation (3.7).
[0218]
(3) When the treated water TP deteriorates, the PAC flow rate is corrected by, for example, the above equation (3.8).
[0219]
As described above, in the sewage treatment plant water quality control apparatus according to the present embodiment, the following effects can be obtained.
[0220]
(A) Predicted values are used for the nitrogen component concentration and the phosphorus component concentration of the influent water 1 flowing into the sewage treatment plant. Therefore, even in a field where a nitrogen component concentration meter and a phosphorus component concentration meter cannot be attached. Can be applied.
[0221]
(B) Instead of the organic substance concentration meter, the UV meter 30 capable of continuous measurement with relatively high accuracy is used to measure the organic component concentration, so that more effective control is performed. It becomes possible.
[0222]
(C) Since the manipulated variable is corrected by feedback (FB) control using the measured values of the total nitrogen and total phosphorus meter of the discharged water quality, the control is performed without deteriorating the water quality of the treated water 3. It becomes possible.
[0223]
(D) By using the ammonia meter 32 attached to the aerobic tank 12, it is determined whether the deterioration of the total nitrogen in the treated water 3 is due to defective nitrification or defective denitrification, and the aeration air volume and circulation flow rate are controlled. Therefore, more efficient nitrogen removal can be performed.
[0224]
(Modification 1)
The flow meter 31 and the UV meter 30 in FIG. 3 may be attached to the water pipe 50 as attachment positions.
[0225]
Moreover, if it is a front | former stage part of an aeration tank, such as the first sedimentation tank 2, an inflow tank, a sand basin, a pump well, etc., it can be used in any position.
[0226]
Further, instead of the flow meter 31, a flow rate calculated by a QH curve from a measured value of a water level meter installed in a pump well can be used.
[0227]
(Modification 2)
You may make it use not the ultraviolet-ray (UV) intensity | strength but the measured value of the densitometer which measures an organic substance component directly as an organic substance component density | concentration.
[0228]
(Modification 3)
The phosphorus component concentration and nitrogen component concentration of the influent water 1 flowing into the sewage treatment plant were attached to the upstream part of the aeration tank, such as the water pipes 50 and 51, the first sedimentation basin 2, the inflow basin, the sand basin, and the pump well. TP meter, PO_FourMeter and TN meter, NH_FourYou may make it utilize the measured value of a meter.
[0229]
(Modification 4)
Water pipes 50 and 51, first sedimentation basin 2, inflow basin, sand basin, pump well, etc._FourMeter and TN meter, NH_FourEven in a sewage treatment plant where a meter is attached, control may be performed using a value predicted by inflow water quality pattern prediction.
[0230]
(Modification 5)
The operation amount 8a calculated by the control unit 8 in FIG. 1 includes a circulation flow rate, a return flow rate, an aeration air amount, a carbon source injection amount, a flocculant injection amount, an excess sludge flow rate, a return water flow rate, and a primary sedimentation bypass valve. It may be at least one of them.
[0231]
(Modification 6)
As a mounting position of the TN meter 33 and the TP meter 34 of the treated water 3 in FIG. 3, the rear stage portion of the aerobic tank 12, the water pipe 52, and the final sedimentation tank 13 are not necessarily located at the water pipe 60. Any position may be used as long as the biological water treatment is almost completed.
[0232]
(Modification 7)
The nitrogen component concentration meter 5 that measures the nitrogen component of the treated water 3 for control correction may be any one of ammonia nitrogen concentration, nitrate nitrogen concentration, and nitrite nitrogen concentration instead of the TN meter 33. Alternatively, the correction may be performed using a plurality instead of one.
[0233]
(Modification 8)
As a phosphorus component concentration meter for measuring the phosphorus component of the treated water 3 for control correction, the phosphoric acid phosphorus concentration may be used instead of the TP meter 34, and the correction may be made using a plurality instead of one. You may make it perform.
[0234]
(Modification 9)
The control correction is performed by a DO meter, an ORP meter, a pH meter attached to a part where biological water treatment is almost completed, such as the rear stage of the aerobic tank 12, the water pipe 52, the final sedimentation basin 13, the water pipe 60, etc. , SS quality meter, MLSS meter, water quality sensor such as UV meter, etc. may be used.
[0235]
(Modification 10)
The manipulated variable output calculated by the control unit 8 in FIG. 3 may be any output as long as it is based on the deviation, as long as it is not linearly proportional to the deviation as described above.
[0236]
For example, a value proportional to the logarithm of the deviation, an exponential function, a value proportional to a power, or a combination of these may be used.
[0237]
(Modification 11)
The output from the control correction unit 35 may be any output as long as it is based on the deviation, without being linearly proportional to the deviation.
[0238]
For example, a value proportional to the logarithm of the deviation, an exponential function, a value proportional to a power, or a combination of these may be used.
[0239]
(Other embodiments)
The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention at the stage of implementation.
For example, in each of the above-described embodiments, the case where the present invention is applied to a sewage treatment plant including an aeration tank including a combination of an anaerobic tank, an oxygen-free tank, and an aerobic tank is described. The same effect can be obtained by applying the present invention in the same manner as described above to a sewage treatment plant including an aeration tank constituted by a combination of an anaerobic tank and an aerobic tank.
[0240]
In addition, the embodiments may be implemented in appropriate combinations as much as possible, and in that case, combined effects can be obtained.
Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements.
For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem (at least one) described in the column of the problem to be solved by the invention can be solved, and the effect of the invention can be solved. When (at least one of) the effects described in the column can be obtained, a configuration in which this configuration requirement is deleted can be extracted as an invention.
[0241]
【The invention's effect】
As described above, according to the sewage treatment plant water quality control apparatus of the present invention, the C / N ratio between the nitrogen component and the organic component of the influent water or / and the C / P ratio between the phosphorus component and the organic component are used. Therefore, at least one of the circulation flow rate, return flow rate, aeration air flow rate, carbon source injection rate, surplus sludge flow rate, return water flow rate, and primary sedimentation bypass valve in the sewage treatment plant is controlled. Even if the water quality balance such as the C / N ratio between the nitrogen component and the organic component and the C / P ratio between the phosphorus component and the organic component deteriorates, the water discharged from the sewage treatment plant is discharged. It is possible to remove nitrogen and phosphorus while always maintaining good quality of water nitrogen and phosphorus.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a first embodiment of a sewage treatment plant water quality control apparatus according to the present invention.
FIG. 2 is a block diagram showing a second embodiment of a sewage treatment plant water quality control apparatus according to the present invention.
FIG. 3 is a block diagram showing a third embodiment of a sewage treatment plant water quality control apparatus according to the present invention.
FIG. 4 is a relationship diagram for explaining the operation of the sewage treatment plant water quality control apparatus according to the third embodiment.
FIG. 5 is a relationship diagram for explaining the operation of the sewage treatment plant water quality control apparatus according to the third embodiment.
FIG. 6 is a relationship diagram for explaining the operation of the sewage treatment plant water quality control apparatus according to the third embodiment.
FIG. 7: Coagulant injection type anaerobic-anoxic-aerobic method (coagulant injection A₂The flowchart which shows the structural example of the sewage treatment plant provided with the aeration tank comprised from the process of O method.
FIG. 8 is a block diagram showing a configuration example of a conventional sewage treatment plant water quality control apparatus.
[Explanation of symbols]
1 ... Influent water
2 ... First sedimentation pond
3 ... treated water
4 ... TOC meter
5 ... TN meter
6 ... C / N ratio calculation unit
6 '... C / P ratio calculation unit
6 ″… C / N ratio, C / P ratio calculation unit
7 ... Standard C / N ratio setting device
7 '... Standard C / P ratio setter
7 "... Standard C / N ratio, C / P ratio setter
8. Control unit
9 ... Aeration device
10 ... Anaerobic tank
11 ... Oxygen-free tank
12 ... Aerobic tank
13 ... Final sedimentation basin
14 ... circulation pump
15 ... Return pump
16 ... PAC infusion pump
17 ... Surplus pump
18 ... First withdrawal pump
19 ... Carbon source injection pump
20 ... Sludge storage tank
21 ... Carbon source storage tank
22 ... Flocculant storage tank
23 ... First-sink bypass valve
24 ... Valve
25 ... TP meter
26 ... Influent water quality database
27 ... Weather information prediction part
28 ... Water quality pattern database
29 ... Inflow water quality prediction section
30 ... UV meter
31 ... Flow meter
32 ... NH_FourTotal
33 ... TN meter
34 ... TP meter
35 ... Control correction unit
36 ... treated water quality determination unit
37 ... UV → BOD converter
38 ... Inflow ratio setting device
50-60 ... Water piping.

Claims (5)

In a sewage treatment plant water quality control device that controls the quality of treated water discharged from a sewage treatment plant equipped with an aeration tank including an anaerobic tank and an aerobic tank ,
Phosphorus component concentration measuring means for measuring the phosphorus component concentration of the inflow water flowing into the sewage treatment plant;
An organic component concentration measuring means for measuring an organic component concentration of the influent water flowing into the sewage treatment plant;
Based on the phosphorus component concentration and the organic substance component concentration measured by the phosphorus component concentration measuring means and the organic substance component concentration measuring means, the ratio of the phosphorus component and the organic substance component of the inflow water flowing into the sewage treatment plant (C / P ratio) C / P ratio calculating means for calculating
C / P ratio setting means for setting a reference C / P ratio as a reference;
Based on the difference between the reference C / P ratio set by the C / P ratio setting means and the C / P ratio calculated by the C / P ratio calculation means, it is returned from the final sedimentation tank to the aeration tank. return flow of precipitation water, flowing water flow return from the sludge storage tank of the flowing water return return flow Sareru the aeration tank, the aeration air quantity, the carbon source injection quantity, coagulant injection amount, excess sludge flow rate, at least one of the first precipitation bypass valve Control means for outputting an operation amount for controlling one;
A sewage treatment plant water quality control apparatus comprising: Sewage treatment plant water quality control device for controlling the quality of treated water discharged from a sewage treatment plant equipped with an anaerobic tank and an aerobic tank, or an aeration tank comprising a combination of an anaerobic tank, an anaerobic tank and an aerobic tank In
Phosphorus component concentration measuring means for measuring the phosphorus component concentration in the anaerobic tank;
Organic substance component concentration measuring means for measuring the organic substance component concentration of the inflow water flowing into the anaerobic tank,
C / P ratio calculating means for calculating a ratio (C / P ratio) between the phosphorus component and the organic component based on the phosphorus component concentration and the organic component concentration measured by the phosphorus component concentration measuring means and the organic substance concentration measuring means. When,
C / P ratio setting means for setting a reference C / P ratio as a reference;
Based on the difference between the reference C / P ratio set by the C / P ratio setting means and the C / P ratio calculated by the C / P ratio calculation means, it is returned from the final sedimentation tank to the aeration tank. return flow of precipitation water, return flow Sareru return water flow of return water flow rate from the sludge storage tank to the aeration tank, the aeration air quantity, the carbon source injection amount, excess sludge flow, to control at least one of the first precipitation bypass valve Control means for outputting an operation amount;
A sewage treatment plant water quality control apparatus comprising: In sewage treatment plant water quality control apparatus according to any one of claims 1 or claim 2,
As the phosphorus component concentration measuring means, a concentration meter that measures either phosphoric acid phosphorus concentration or total phosphorus concentration is used. As the organic component concentration measuring means, biochemical oxygen demand (BOD), chemical oxygen is used. A sewage treatment plant water quality control apparatus characterized by using a densitometer that measures either the required amount (CODMn, CODcr) or the total organic carbon amount (TOC). In the sewage treatment plant water quality control device according to any one of claims 1 to 3 ,
The flow rate of the inflow water flowing into the sewage treatment plant, an inlet water quality database for storing the time-series data of the re-emission component concentration measuring means and the measured value of the water component by organic component concentration measuring means, and the water quality test results manual analysis ,
Based on the time-series data stored in the inflow water quality database, the inflow water quality prediction means for predicting the phosphorus component concentration of the inflow water flowing into the sewage treatment plant, and the organic matter component concentration,
It said inlet phosphorus component concentration predicted by quality prediction means, using the organic component concentration, pre Symbol sewage water control apparatus is characterized in that so as to calculate the C / P ratio. In the sewage treatment plant water quality control device according to any one of claims 1 to 4 ,
Nitrogen component concentration measuring means for measuring the nitrogen component concentration of the influent water flowing into the sewage treatment plant;
An organic component concentration measuring means for measuring an organic component concentration of the influent water flowing into the sewage treatment plant;
Based on the nitrogen component concentration and the organic substance component concentration measured by the nitrogen component concentration measuring means and the organic substance component concentration measuring means, the ratio of the nitrogen component and the organic substance component of the inflow water flowing into the sewage treatment plant (C / N ratio) C / N ratio calculating means for calculating
Reference C / N ratio setting means for setting a reference C / N ratio as a reference;
Further comprising a <br/> the flow rate measuring means for measuring the flow rate of the inflow water flowing into the sewage treatment plant,
The control means includes a flow rate value measured by the flow rate measurement means, a reference C / N ratio set by the reference C / N ratio setting means, and a C / N ratio calculated by the C / N ratio calculation means. And the difference between the reference C / P ratio set by the C / P ratio setting means and the C / P ratio calculated by the C / P ratio calculation means , and circulates in the aeration tank. Circulating flow rate of untreated water, return flow rate of precipitated water returned from the final settling tank to the aeration tank, return water flow rate of return water returned from the sludge storage tank to the aeration tank, aeration air volume, carbon source injection volume, excess sludge flow, the sewage treatment plant water quality control apparatus is characterized in that so as to output an operation amount for controlling at least one of the first precipitation bypass valve.

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