JP3732630B2

JP3732630B2 - Waste water catalytic oxidation

Info

Publication number: JP3732630B2
Application number: JP26033497A
Authority: JP
Inventors: 哲夫片岡; 信岸田
Original assignee: NGK Insulators Ltd
Current assignee: NGK Insulators Ltd
Priority date: 1997-05-13
Filing date: 1997-09-25
Publication date: 2006-01-05
Anticipated expiration: 2017-09-25
Also published as: JPH1128486A

Description

【０００１】
【発明の属する技術分野】
本発明は、し尿、下水等の廃水を、接触材が充填された接触酸化槽内で好気性下で生物処理する廃水の接触酸化法に関するものである。
【０００２】
【従来の技術】
接触酸化法は、接触酸化槽内に充填され浸漬された接触材の表面に、微生物を含んだ生物膜を付着させて、好気性下で廃水と接触させて生物処理する処理法であり、し尿処理や下水処理の分野で広く利用されている。
従来の接触酸化法（従来法）は図８に示したように、最初沈澱槽（21）で初沈汚泥と固液分離された廃水は、接触材（28）を備えた接触酸化槽（22）に流入し、接触材（28）の表面に付着した生物膜により接触酸化処理（生物処理）され、初沈汚泥は初沈汚泥貯留槽（24）に貯留された後、重力濃縮槽、浮上濃縮槽、遠心濃縮機等の汚泥濃縮設備（25）に供給される。
通常運転時には、この生物処理により生成した生物膜が所定の厚み以上になると少しづつ自然に剥離し、自然剥離した剥離汚泥の一部は微細フロックとなり接触酸化槽（22）に浮遊し、剥離汚泥の残部は接触酸化槽（22）の底部に沈澱する。
【０００３】
従来法（接触材に固定された固定微生物による接触酸化法）の通常運転時には、接触酸化槽（22）の流出水は全て沈澱槽（23）に供給され固液分離される。
通常運転時の流出水の浮遊物濃度は、たとえば２０〜１００ｍｇ／ｌ（リットル）であり、沈澱槽（23）で固液分離された処理水は、通常は処理水水質（浮遊物濃度、濁度、透視度等）を満足するが、流出水の微細フロックは容易に沈澱せずに、そのまま処理水に同伴して、処理水水質を悪化させることもあった。
沈澱槽（23）で固液分離された処理水は沈澱槽（23）の上部から流出し、汚泥は下部へ沈澱して余剰汚泥となる。
通常運転時に接触材（28）の表面に付着した生物膜が所定厚み以上に達すると、生物膜が少しづつ自然剥離するが、その時期は廃水の性状や処理量により変動する。生物膜の自然剥離が一時的に多量に起ると、接触酸化槽（22）からの流出水の浮遊物濃度が高くなり、沈澱槽（23）において完全に固液分離されずに、処理水の水質をさらに悪化させることもあった。
【０００４】
接触酸化法は接触酸化槽（22）内に接触材（28）を設け、接触材（28）の表面に生物膜を形成させて接触酸化処理を行うものであるから、接触材（28）の表面に生物膜が成長して、接触材（28）と接触材（28）との間隙を埋める。
接触酸化処理の経過時間が長くなるに従って廃水の流路の閉塞が起り、廃水は接触材相互の水路の全域を均等に流れずに、特定の流路のみを流れるので、全体として廃水と生物膜との接触が不十分になると共に、酸素の供給も不十分となるので、廃水を所定時間内に充分に生物処理出来なくなることがあった。
上記のような廃水の接触酸化槽（22）の流路の閉塞を解消するために逆洗洗浄が行われる。逆洗洗浄時に底部に沈澱した剥離汚泥の上部に設けられた接触材（28）の直下から、逆洗空気が５〜２０分間噴射されると、接触材（28）から生物膜が強制剥離されて、剥離汚泥の一部は接触酸化槽（22）内に浮遊して、流出水に同伴して流出し、残部は接触酸化槽（22）の底部に剥離汚泥として沈澱する。
【０００５】
通常運転時には一般的に接触酸化槽（22）の底部からの自然剥離汚泥の引き抜きを行わないので、通常運転を継続した後の接触酸化槽（22）の底部には浮遊物濃度が高い自然剥離汚泥が沈澱している。逆洗頻度や接触酸化槽（22）の槽数により異なるが、逆洗洗浄時には接触酸化槽（22）の生物膜が多量に強制剥離されて、浮遊物濃度が数千〜２万ｍｇ／ｌに達する。
接触酸化槽（22）の上部の剥離汚泥を同伴する流出水の浮遊物濃度は、時間経過と共に次第に低下するので、これを汚泥濃縮設備（25）に供給することを継続すると、浮遊物濃度が低い流出水が汚泥濃縮設備（25）に供給されることになり、汚泥濃縮設備（25）の規模を大きくすることが必要となり問題であった。
【０００６】
従来法の逆洗洗浄時において、逆洗洗浄開始後の早い時期においては、浮遊物濃度が高いので剥離汚泥を汚泥濃縮設備（25）に供給しても問題はない。
しかし、接触酸化槽（22）の底部からの剥離汚泥のポンプによる引き抜きを継続すると、剥離汚泥の浮遊物濃度が次第に低下し、浮遊物濃度が低い剥離汚泥が汚泥濃縮設備（25）に供給されるので、汚泥濃縮設備（25）の規模を大きくすることが必要となり問題であった。
このため早い時期に流出水や剥離汚泥を汚泥濃縮設備（25）に供給するのを止めて、沈澱槽（23）に供給すると、剥離汚泥の浮遊物濃度の変動により、浮遊物濃度が高い流出水や剥離汚泥が供給されることになり、沈澱槽（23）の固液分離能力を越えてしまい、処理水の水質（浮遊物濃度、濁度、等）を悪化させると言う問題があった。
【０００７】
単独の接触酸化槽（22）においては、逆洗洗浄後の時間経過による流出水の浮遊物濃度の変化を推定することがある程度出来るが、複数の接触酸化槽（22）が直列に設けられている場合には、廃水は上流側の接触酸化槽（22）から下流側の接触酸化槽（22）へ流れるため、より上流側の接触酸化槽（22）で逆洗洗浄を行う程、剥離汚泥が流出水により希釈されるので、沈澱槽（23）に供給される流出水の浮遊物濃度は、逆洗洗浄後の時間経過と共に、最初の内は低く、剥離汚泥の影響により次第に高くなり、また低くなる。また、引き抜かれる剥離汚泥の浮遊物濃度も、時間経過と共に最初の内は高いが次第に低くなる。
従って、どの位置の接触酸化槽（22）を逆洗洗浄をするかによって、逆洗洗浄により発生した剥離汚泥が流出水に混入する程度は変動してしまうから、どの程度の時間経過後に、流出水の浮遊物濃度をどのように変動するかについて予測するのは、複数の接触酸化槽（22）が直列に設けられている場合には特に難しかった。
【０００８】
すなわち、従来法は逆洗洗浄後に接触酸化槽（22）の上部からの流出する流出水や、接触酸化槽（22）の下部からの引き抜かれる剥離汚泥の浮遊物濃度と流量とを総合した沈澱槽（23）への水面積負荷が、どの程度であるのかを考慮して、流出水や剥離汚泥を沈澱槽（23）へ供給するような制御をしておらずに、担当者が流出水や剥離汚泥の浮遊物濃度を見て、経験により沈澱槽（23）か汚泥濃縮設備（25）へ供給している。
従って、上記のように、浮遊物濃度の高い流出水や剥離汚泥を沈澱槽（23）へ供給する場合には、沈澱槽（23）の固液分離能力を越えてしまい、処理水の水質（浮遊物濃度、濁度、透視度等）を悪化させ、また、浮遊物濃度の低い流出水や剥離汚泥を汚泥濃縮設備（25）に供給する場合には、汚泥濃縮設備（25）を過大な設備にさせる問題があった。
従来法のように、沈澱槽（23）への水面積負荷が、どの程度であるのかを考慮せずに、流出水や剥離汚泥を、担当者の目視に基づく判断により、沈澱槽（23）や汚泥濃縮設備（25）に振り分けていては、沈澱槽（23）と汚泥濃縮設備（25）の処理能力を有効に活用することが出来難い。
【０００９】
し尿処理場や下水処理場に接触酸化装置が建設された場合には、廃水の有機性汚濁物質濃度（たとえば、ＢＯＤ、ＣＯＤ、ＴＯＣ濃度、紫外線吸光度等）と流量の積である有機性汚濁物質の負荷量（たとえば、ＢＯＤ濃度と流量の積であればＢＯＤ負荷量）に合わせて、それを接触酸化処理するのに必要な接触材（28）が充填され、接触材（28）に固定された生物膜の固定微生物により生物処理が行れる。
しかし、上記のような接触酸化装置を建設した後に、水量やＢＯＤ負荷量が当初の計画よりも大幅に増加すると、固定微生物が不足し生物処理は困難となるから増設が必要であるが、その増設用地の確保は都市部では困難であるので深刻な問題となっている。
このため、既存装置を改造して処理能力を増加させることや、新設装置をコンパクト化することにより、建設用地を少なくすることが求められている。
【００１０】
従来法においては、接触酸化槽（22）の流出水に凝集剤を添加していない場合には、沈澱槽（23）で微細フロックが容易に沈澱せず、そのまま処理水に同伴して、処理水の水質を悪化させることがあった。
また、凝集剤を添加する場合においても、添加量を固定していたり、担当者の判断で適当に添加していたので、最適な添加がなされずに、必要充分な固液分離がなされなかったり、凝集剤コストの増大を招くものであり、より適切な凝集剤の添加法が求められていた。
【００１１】
【発明が解決しようとする課題】
本発明はかかる事情を背景としてなされたものであって、廃水の接触酸化法において、浮遊物濃度の高い流出水や剥離汚泥が沈澱槽に供給されて、処理水の水質が悪化するのを防止するとともに、浮遊物濃度の低い流出水や剥離汚泥が汚泥濃縮設備に供給されて、汚泥濃縮設備が増大するのを防止することにより、沈澱槽の有効活用と汚泥濃縮設備規模の縮小を図ることを課題とする。
また、接触酸化装置をコンパクトにし、処理能力を増加させることも課題とするものである。
さらに、適量の凝集剤を添加されることにより、微細フロックや浮遊物を除去して処理水の水質をより向上することを課題とするものである。
【００１２】
【課題を解決する手段】
本発明の第１の発明は、廃水を接触材が充填された接触酸化槽で接触酸化処理した後の流出水を、沈澱槽で固液分離して処理水とする廃水の接触酸化法において、接触酸化槽の流出水の浮遊物濃度と沈澱槽の水面積負荷との関係式である下記の１式の係数ｋ，ａ，ｂ，ｃを予備試験により求めると共に、流出水の水温、ＳＶＩ、および水面積負荷の測定値を、１式に代入することにより得られた流出水の浮遊物濃度の計算値と、前記流出水の浮遊物濃度の測定値とを比較し、前記測定値が前記計算値以下の場合には、前記接触酸化槽の流出水を沈澱槽に供給して固液分離し、前記測定値が、前記計算値を越える場合には、前記接触酸化槽の流出水を汚泥濃縮設備に供給して濃縮することを特徴とする廃水の接触酸化法である。

【００１３】
第２の発明は、廃水を接触材が充填された接触酸化槽で接触酸化処理した後の流出水を、沈澱槽で固液分離して処理水とする廃水の接触酸化法において、接触酸化槽の流出水の浮遊物濃度と沈澱槽の水面積負荷との関係式である下記の１式の係数ｋ，ａ，ｂ，ｃを予備試験により求めると共に、流出水の水温、ＳＶＩ、、および浮遊物濃度の測定値を、１式に代入することにより得られた流出水の水面積負荷の計算値と、前記流出水の水面積負荷の測定値とを比較し、前記測定値が前記計算値以下の場合には、前記接触酸化槽の流出水を沈澱槽に供給して固液分離し、前記測定値が前記計算値を越える場合には、前記接触酸化槽の流出水を汚泥濃縮設備に供給して濃縮することを特徴とする廃水の接触酸化法である。

【００１４】
第３の発明は、第１または２の発明において、異なる浮遊物濃度の流出水に凝集剤を添加して固液分離する際に、処理水の浮遊物濃度を目標値以下に維持し得る凝集剤添加量と流出水の浮遊物濃度との検量線を予備試験により求め、この検量線を利用して流出水の浮遊物濃度に応じて凝集剤を添加した後、沈澱槽で固液分離することを特徴とする廃水の接触酸化法である。
【００１５】
第４の発明は、廃水を接触材が充填された接触酸化槽で接触酸化処理した後の流出水を、沈澱槽で固液分離して処理水とする廃水の接触酸化法において、接触酸化槽の剥離汚泥の浮遊物濃度と沈澱槽の水面積負荷との関係式である下記の１式の係数ｋ，ａ，ｂ，ｃを予備試験により求めると共に、剥離汚泥の水温、ＳＶＩ、および水面積負荷の測定値を、１式に代入することにより得られた剥離汚泥の浮遊物濃度の計算値と、前記剥離汚泥の浮遊物濃度の測定値とを比較し、前記測定値が前記計算値以下の場合には、前記接触酸化槽の剥離汚泥を沈澱槽に供給して固液分離し、前記測定値が、前記計算値を越える場合には、前記接触酸化槽の剥離汚泥を汚泥濃縮設備に供給して濃縮することを特徴とする廃水の接触酸化法である。

【００１６】
第５の発明は、廃水を接触材が充填された接触酸化槽で接触酸化処理した後の流出水を、沈澱槽で固液分離して処理水とする廃水の接触酸化法において、接触酸化槽の剥離汚泥の浮遊物濃度と沈澱槽の水面積負荷との関係式である下記の１式の係数ｋ，ａ，ｂ，ｃを予備試験により求めると共に、剥離汚泥の水温、ＳＶＩ、および浮遊物濃度の測定値を、１式に代入することにより得られた剥離汚泥の水面積負荷の計算値と、前記剥離汚泥の水面積負荷の測定値とを比較し、前記測定値が前記計算値以下の場合には、前記接触酸化槽の剥離汚泥を沈澱槽に供給して固液分離し、前記測定値が前記計算値を越える場合には、前記接触酸化槽の剥離汚泥を汚泥濃縮設備に供給して濃縮することを特徴とする廃水の接触酸化法である。

【００１７】
第６の発明は、第４または５の発明において、異なる浮遊物濃度の剥離汚泥に凝集剤を添加して固液分離する際に、処理水の浮遊物濃度を目標値以下に維持し得る凝集剤添加量と剥離汚泥の浮遊物濃度との検量線を予備試験により求め、この検量線を利用して剥離汚泥の浮遊物濃度に応じて凝集剤を添加した後、沈澱槽で固液分離することを特徴とする廃水の接触酸化法である。
【００１８】
第７の発明は、沈澱槽で固液分離された汚泥の一部を、返送汚泥として接触酸化槽に返送することを特徴とする第１〜６のいずれかの発明に記載の廃水の接触酸化法である。
【００１９】
【発明の実施の形態】
本発明の実施の形態を、図１に示した第１の実施例（接触材に固定された固定微生物による接触酸化法）について説明する。
通常運転時において、最初沈澱槽（１）で固液分離された後に流出する廃水は、接触材（８）が充填された接触酸化槽（２）に供給され、最初沈澱槽（１）の下部に沈澱した初沈汚泥は初沈汚泥貯留槽（４）に貯留された後、汚泥濃縮設備（５）に供給される。
接触材（８）が充填された接触酸化槽（２）に流入した廃水は、接触材（８）の表面に付着した生物膜の働きにより生物処理される。
生物処理により次第に成長した生物膜は、所定の厚さになると接触材（８）から自然に剥離し、剥離汚泥として接触酸化槽（２）の底部に沈澱し、一部は微細フロックとなり槽内に浮遊し、やがて流出水に同伴して沈澱槽（３）へ流出する。なお、接触酸化槽（２）には、ひも状接触材、たとえば、日本産業機械製のリングレース（登録商標）、網状接触材、たとえば、新光ナイロン製のヘチマロン（登録商標）、東レ製のバイオコーム（登録商標）等の接触材の内部に多くの空隙を有する接触材（８）が充填されている。
【００２０】
第１の実施例の通常運転時には、流出水の浮遊物濃度は、たとえば２０〜１００ｍｇ／ｌ（リットル）と比較的低く、その変動幅も小さいので、微細フロックの流出が多少あるものの水質上のトラブルは少ない。
しかし、逆洗洗浄時には、逆洗洗浄する接触酸化槽（２）の位置や逆洗洗浄の頻度等により、逆洗洗浄時の流出水や剥離汚泥の浮遊物濃度がかなり変動するので、流出水や剥離汚泥を担当者が目視することにより、担当者が適当に沈澱槽へ供給したり、汚泥濃縮設備に供給したりするので、トラブルが起き易い。
本発明は、接触酸化槽（２）の流出水や剥離汚泥の浮遊物濃度と水面積負荷（ｍ³／ｍ²／日）の関係を示す１式を利用して、流出水や剥離汚泥を沈澱槽（３）に供給するか、汚泥濃縮設備に供給するかを、沈澱槽（３）への負荷量により選択することを特徴とするものであり、特に逆洗洗浄時に有効な方法である。
【００２１】
以下に、第１の実施例に基づいて本発明の方法の説明をする。
なお、水面積負荷（ｍ³／ｍ²／日）とは、沈澱槽に供給される流量（ｍ³／日）を、沈澱槽の有効な表面積（ｍ²）で割ったものである。沈澱槽における浮遊物の除去率は、沈澱槽の表面積と汚泥粒子の沈降速度に比例し、廃水の流量に反比例する。
従って、廃水の流量を沈澱槽の表面積をで割った水面積負荷は、沈澱槽の浮遊物の除去率を決定する上で重要な設計仕様である。
沈澱槽で滞留時間内に固液分離されるためには、沈澱槽の水面積負荷（流出水の上昇流速）を、汚泥粒子の沈降速度よりも小さくする必要があると共に、汚泥粒子は相対的な沈降速度差で沈降して、滞留時間内に沈澱槽の底に到着する必要がある。この両者から必要な水面積負荷が決定される。
試験データを非線型回帰分析法（パウエル法）により解析することにより、水面積負荷は、水温、浮遊物濃度およびＳＶＩの関数として表すことが出来る。
Ｍ＝ｋ・Ｔ^a・Ｎ^-b・（ＳＶＩ）^-c ・・・・・・・１式
ここで、係数ｋ、ａ，ｂ，ｃは廃水の性状や汚泥の性状により、変動する係数であり、予備試験により決定される。
たとえば、下水処理における活性汚泥に対して、係数ｋ、ａ，ｂ，ｃは下記の２式で定義される。

試験開始時において、都合により予備試験が出来ない場合には、下水の処理なら、暫定的に上記の係数を用いて処理し、対象とする流出水の試験データが蓄積された時点で、より妥当な係数ｋ、ａ，ｂ，ｃに変更れば良い。
流出水の水温、ＳＶＩ，流量、水面積負荷、浮遊物濃度、等はその都度の測定値を利用することが好ましいが、それぞれの値を既存データに基づいて設定することも出来る。
２式において、係数ｋ、ａ，ｂ，ｃ、廃水の水温、および、ＳＶＩを代入すると、水面積負荷は廃水の浮遊物濃度の関数として表されるから、水面積負荷の数値を与えると、水面積負荷に対応する廃水の浮遊物濃度が計算により得られる。
なお、ＳＶＩ（汚泥容量指標）は、容器内に汚泥を３０分間静置させた時の１ｇの汚泥が占める容積をｍｌで表したもので、汚泥の沈降性の良否を示す指標であり、一般的には時間の単位で変動する因子ではないため、直近の測定値で代用することも可能である。
流出水のＳＶＩが１００である場合に比較して、ＳＶＩが１２０である時の方が、固液分離がし難いので、沈澱槽に供給できる浮遊物濃度は低いことを示す。
【００２２】
ここで予備試験により係数ｋ、ａ，ｂ，ｃが求められ、２式のような関係式が得られた際に、流出水の水温が２０℃、ＳＶＩが１２０であった場合に、流出水を沈澱槽に供給するか、汚泥濃縮設備に供給するかの選択方法について説明する。下水の接触酸化槽の流出水について予備試験により得られた２式に、流出水のＳＶＩ＝１２０と水温＝２０℃を代入し、さらに沈澱槽に供給される流量（ｍ³／日）を、沈澱槽の有効な表面積（ｍ²）で割った水面積負荷M2を代入して計算すると、水面積負荷M2に対応する流出水の浮遊物濃度の計算値N2が求められ、これから座標点Ｑ（M2,N2)が決まり、このような計算を行うと、図６に示すような曲線が描かれる。
ここで、測定により得られた選別すべき流出水の水温＝２０℃、ＳＶＩ＝１２０、水面積負荷＝M2、浮遊物濃度＝N1であったとすると、図６上に点P (M2,N1) として表されるが、水面積負荷＝M2に対する流出水の浮遊物濃度の測定値N1は計算値N2よりも小さく、点Ｐは曲線ＳＶＩ＝１２０の下側領域にあるので、沈澱槽（３）において固液分離が可能と判断され、流出水は沈澱槽（３）に供給される。一方、測定により得られた選別すべき流出水の水温＝２０℃、ＳＶＩ＝１２０、水面積負荷＝M2、浮遊物濃度の測定値＝N3であったとすると、点Ｒ(M2,N3) として表されるが、水面積負荷＝M2に対する流出水の浮遊物濃度の測定値N3は計算値N2よりも大きく、点Ｒは曲線ＳＶＩ＝１２０の上側領域にあるので、沈澱槽（３）において固液分離が不可能と判断され、流出水は汚泥濃縮設備（５）に供給される。
なお、剥離汚泥についても、逆洗洗浄時の流出水と同様に予備試験を実施し、同様な方法により処理することが出来るが、両者が性状的には類似している場合には、予備試験結果を準用することも出来る。
【００２３】
上記のように、流出水の浮遊物濃度と水面積負荷との関係を示す曲線の下側領域にある場合には、流出水は沈澱槽（３）で安定的に固液分離される。
なお、流出水に凝集剤を添加する場合には、沈澱槽（３）での固液分離能力が向上するので、沈澱槽（３）で処理できる流出水の流量が増加する。
従って、沈澱槽（３）の固液分離能力が有効に活用されると共に、汚泥濃縮設備（５）の規模を縮小することが出来る。
一方、流出水の浮遊物濃度と水面積負荷との関係を示す曲線の上側領域にある場合には、汚泥濃縮設備（５）へ供給され、必要に応じて濃縮されて、汚泥処理設備に送られる。
【００２４】
運転当初は暫定的に設定された係数ｋ、ａ，ｂ，ｃにより計算された関係式により上記のような選別を行うが、このような選別を行った後に沈澱槽（３）からの処理水の水質を測定し、水質が基準値を満足しているか、否かを調査することが必要である。
このような調査を年間を通じて継続すると、データが蓄積されるので、蓄積されたデータをフィードバックして、新しい係数ｋ、ａ，ｂ，ｃを設定することよりより良い制御を行うことができる。
逆洗洗浄する接触酸化槽（22）の位置や逆洗洗浄の頻度等により変動する剥離汚泥を含有する流出水を、担当者が目視することにより、経験的に適宜に時間を決めて、剥離汚泥の引き抜きを行ない、沈澱槽（23）または汚泥濃縮設備（25）を選択して供給した従来法に比較して、本発明法は流出水や剥離汚泥の浮遊物濃度（ｍｇ／ｌ）と沈澱槽（３）の水面積負荷（ｍ³／ｍ²／日）の関係を利用して、流出水や剥離汚泥を沈澱槽（３）に供給するか、汚泥濃縮設備（５）に供給するかを選択するので、たとえ流出水や剥離汚泥の浮遊物濃度が変動したとしても的確で安定的な処理ができる。
上記の例では水面積負荷や浮遊物濃度を指標にして、沈澱槽（３）の固液分離の能力をオーバーした場合には、全量を汚泥濃縮設備（５）に供給したが、流出水や剥離汚泥を、沈澱槽（３）と汚泥濃縮設備（５）とに分配することも出来る。すなわち、流出水の一部を沈澱槽（３）で固液分離可能な分を沈澱槽（３）に供給し、固液分離能力をオーバーする前部を汚泥濃縮設備（５）に供給する方法である。この方法は、制御が若干複雑になるが、沈澱槽（３）がより有効に利用できると言う利点がある。
なお、本発明において、処理方法を変更する浮遊物濃度や水面積負荷を、所定数値以下の場合と越える場合とに区分したが、所定数値未満の場合と以上の場合とに区分することと実質同一であり、これも本発明に含まれるものである。
【００２５】
上記の例では、先に水面積負荷を代入して、浮遊物濃度により流出水を沈澱槽（３）に供給するか、汚泥濃縮設備（５）に供給するかのいずれか選択をしたが、別の方法として、先に浮遊物濃度を代入して、水面積負荷により流出水を沈澱槽（３）に供給するか、汚泥濃縮設備（５）に供給するかの選択をすることもできる。
制御方法としては、、測定により得られた選別すべき流出水の水温＝２０℃、ＳＶＩ＝１２０、水面積負荷＝M1、浮遊物濃度＝N2であったとすると、図６上に点Ｓ(M1,N2) として表されるが、浮遊物濃度＝N2に対する流出水の水面積負荷の測定値M1は計算値M2よりも小さく、点Ｓは曲線ＳＶＩ＝１２０の下側領域にあるので、沈澱槽（３）において固液分離が可能と判断され、流出水は沈澱槽に供給される。
一方、測定により得られた選別すべき流出水の水温＝２０℃、ＳＶＩ＝１２０、水面積負荷＝M4、浮遊物濃度の測定値＝N2であった；すると、図６上に点Ｔ(M4,N2) として表されるが、浮遊物濃度＝N2に対する流出水の水面積負荷の測定値M4は計算値M2よりも大きく、点Ｔは曲線ＳＶＩ＝１２０の上側領域にあるので、沈澱槽（３）において固液分離が不可能と判断され、流出水は汚泥濃縮設備（５）に供給される。
なお、水面積負荷（ｍ³／ｍ²／日）とは、沈澱槽に供給される流量（ｍ³／日）を、固定値である沈澱槽の有効な表面積（ｍ²）で割ったものであるから、水面積負荷により選択することは、流量により選択することと実質的に同一であり、流量により流出水を沈澱槽（３）に供給するか、汚泥濃縮設備（５）に供給するかの選択をすることも出来る。
【００２６】
第１の実施例（接触材に固定された固定微生物による接触酸化法）について説明して来たが、接触酸化槽（２）内に充填される接触材（８）の充填量は、設計条件に応じた量が充填され、接触材（８）の比表面積は固定されているから、接触材（８）に固定される微生物量は自ずと限定されて、容積当たりの処理能力は固定されている。従って、廃水の性状変動や流量変動による有機性汚濁物質の負荷量の変動があると容易に対応することが出来ない。
このため、接触材に固定された固定微生物と返送汚泥による浮遊微生物とを併用した接触酸化法を開発した。
微生物量を増加させたこの方法によれば、装置サイズを変更せずに負荷量の増加および変動に容易に対応出来るから、装置サイズをコンパクトにすることが可能になる。
この本発明の第２の実施例（接触材に固定された固定微生物と返送汚泥による浮遊微生物とによる接触酸化法）について、以下に説明する。
【００２７】
第２の実施例の接触酸化法は、図７に示すように、第１の実施例の接触酸化法において、接触材（８）が充填された接触酸化槽（２）に返送汚泥を、必要な微生物濃度に応じてたとえば、２０〜５０％返送する工程を付加したものである。
廃水の有機性汚濁物質濃度は廃水の流入側である上流に行く程高いので、接触材（８）相互間の目詰りは上流側に行く程起り易い傾向にある。
返送汚泥の返送位置は、微生物量が満足されるならば、微生物濃度が高い最前段に返送汚泥を返送せずに、微生物濃度が不足し微生物濃度が低い後段（たとえば、第３段）に返送汚泥を分配して返送して微生物濃度を増加させることが好ましい。
返送汚泥を返送する第２の実施例においては、接触酸化槽（２）の流出水の浮遊物濃度は、たとえば、１０００〜２０００ｍｇ／ｌと高くなり、逆洗洗浄時には、この値がプラスされるから、流出水の浮遊物濃度や水面積負荷に応じて、沈澱槽（３）に供給するか、汚泥濃縮設備（５）に供給するかの選択をすることは重要である。
なお、接触酸化槽（２）の目詰りの有無は、一般に取り出し可能な試験片の生物膜の厚みを目視観察することや槽内に黒色味を帯びた嫌気性の浮遊汚泥が増加し、嫌気臭がしているか、否かを目視観察すること等により判断する。
【００２８】
第２の実施例の接触酸化法は、接触材に固定された固定微生物と返送汚泥による浮遊微生物とにより生物処理する方法であり、接触酸化槽（２）内の接触材に固定された固定微生物のみにより生物処理する第１の実施例の接触酸化法と比較すると、接触酸化槽内の微生物量を増加させることが出来るので、同一の装置サイズならば負荷量を増加させることが出来るし、同一負荷量ならば装置サイズをコンパクトにすることが出来る方法であるので、新設や増設の際に必要な用地面積を減少させることが出来るので好ましい。
【００２９】
第１の実施例の接触酸化法においては、生物膜から自然に剥離した剥離汚泥の一部は、数十μｍ以下の微細フロックとしてそのまま流出水に同伴して沈澱槽に流入し、そこで除去されずに処理水質を悪化させることがあった。
第２の実施例の接触酸化法においては、返送汚泥を返送しているので、接触酸化槽（２）内の微細フロックは好気性菌を主体とする浮遊微生物の吸着作用によりほとんど吸着されて、沈降し易い数百μｍの大きなフロックとなるので、沈澱槽で容易に沈澱し固液分離される。
微細フロックを除去するために流出水に凝集剤を添加すが必要でなくなるか、凝集剤を添加するにしても、凝集剤の添加量を大幅に減少させることが出来るとの利点がある。
【００３０】
逆洗洗浄時に、沈澱槽（３）に供給された流出水は、より固液分離され易くするため、別の予備試験により求めた、図４に示す逆洗洗浄時の処理水の浮遊物濃度と凝集剤添加量の関係や、図５に示す逆洗洗浄時の流出水の浮遊物濃度と凝集剤添加量の関係を利用して、流出水に凝集剤が添加された後、沈澱槽（３）に供給されることが好ましい。
次に、流出水や剥離汚泥に凝集剤を添加する場合の添加方法を説明する。
第１の実施例の通常運転時に、接触酸化槽（２）の流出水に添加される凝集剤の添加量を決定するには、たとえば図２に示すように、浮遊物濃度の異なる下水を接触酸化した各種の浮遊物濃度の流出水に凝集剤（たとえば無機凝集剤ＰＡＣ）を添加し、沈澱処理後の処理水の浮遊物濃度と凝集剤添加量との関係を示す図を作成する。
【００３１】
図２は浮遊物濃度が１８〜５２ｍｇ／ｌの下水の接触酸化槽（２）の流出水に、凝集剤を２０〜４０ｍｇ／ｌ添加した後に沈澱させると、処理水の浮遊物濃度はより低下することを示している。
流出水の浮遊物濃度に応じて、凝集剤の添加量を増減すれば、効果的、経済的に処理水の水質目標を満足することが出来る。
本発明において、通常運転時に微細フロックを含有する接触酸化槽（２）の流出水は、浮遊物濃度および流量が測定され、測定された浮遊物濃度および流量から流出水の乾燥固形物量が演算制御器（６）により演算され、この乾燥固形物量に応じて、演算制御器（６）からの信号に基づいて、予備試験により設定された処理水の浮遊物濃度を所定の目標値以下に維持し得る凝集剤添加量と流出水の浮遊物濃度との検量線を予備試験により求め、この検量線により所定量の凝集剤が、凝集剤供給機（７）により添加される。
所定量の凝集剤が添加された後の流出水は沈澱槽（３）に流入され、沈澱槽（３）で処理水と汚泥（余剰汚泥）とに固液分離される。本発明法の廃水の接触酸化方法においては、凝集剤が添加されているため、微細フロックは略完全に固液分離される。
上記のデ−タから、たとえば、処理水の浮遊物濃度の目標値を１０ｍｇ／ｌ以下にするなら、図３に示すような流出水の浮遊物濃度と凝集剤の添加量との関係を示す検量線を作成し、この検量線により流出水の浮遊物濃度に対する凝集剤添加量が決定される。
【００３２】
沈澱槽（３）で沈澱された後の処理水の浮遊物濃度が演算制御器（６）により連続的または断続的に測定される。測定された処理水の浮遊物濃度がフィードバックされて、予備試験により得られた流出水の浮遊物濃度と凝集剤添加量と処理水の浮遊物濃度の関係が補正され、より適正な凝集剤添加量が新たに設定されることになる。し尿処理場や下水処理場においては、常時運転が行われているので、このようなデ−タを蓄積することにより、より正確に制御することが出来る。
なお、接触酸化槽（２）の流出水の浮遊物濃度と濁度との間には、相関関係があるので、浮遊物濃度の代わりに濁度を利用して同様な制御を行うことも出来る。接触酸化槽（２）の流出水の浮遊物濃度に応じて凝集剤が添加されているので、従来法のように凝集剤を添加しない場合に比較して、微細フロックが固液分離され易く、沈澱槽（３）から流出する処理水の水質は大幅に向上する。
沈澱槽（３）の底部に沈澱した汚泥は汚泥濃縮設備（５）に供給されて、そこで濃縮された後、たとえば、真空脱水機、汚泥焼却炉等の汚泥処理設備に供給されて処理される。
【００３３】
逆洗洗浄時に、剥離汚泥を多量に含有する接触酸化槽（２）の流出水に添加される凝集剤の添加量の決定は、通常運転時と略同様に決定することが出来る。
たとえば図４に示すように、下水を接触酸化した接触酸化槽（２）の浮遊物濃度の異なる流出水に、凝集剤（たとえば、無機凝集剤ＰＡＣ）を添加し、沈澱処理後の処理水の浮遊物濃度と凝集剤添加量との関係を示す図を作成する。
図４は浮遊物濃度が２０００〜４０００ｍｇ／ｌの下水の接触酸化槽（２）の流出水に、凝集剤を７０〜１５０ｍｇ／ｌ添加した後に沈澱させると、処理水の浮遊物濃度はより低下することを示している。
流出水の浮遊物濃度に応じて、凝集剤添加量を増減すれば、処理水の目標濃度が変更されても対応できる。
【００３４】
接触酸化槽（２）の流出水の浮遊物濃度は、演算制御器（６）により連続的または断続的に測定される。測定された浮遊物濃度、浮遊物濃度平均値等に応じて、浮遊物濃度と凝集剤添加量との関係を利用して、処理水の浮遊物濃度の目標濃度を満足する凝集剤添加量が演算され、その信号に基づいて演算された所定量の凝集剤が凝集剤供給機（７）により添加される。
接触酸化槽（２）の流出水に凝集剤が添加され、沈澱槽（３）で沈澱された後の処理水の浮遊物濃度が演算制御器（６）により連続的または断続的に測定されるが、これらの浮遊物濃度が所期の濃度でない場合には、この結果をフィードバックして、予備試験により得られた流出水の浮遊物濃度と凝集剤添加量と処理水の浮遊物濃度の関係が補正され、より適正な添加量が設定されることが好ましい。剥離汚泥の制御方法についても、流出水の場合と同様にすることが出来る。
【００３５】
【発明の効果】
▲１▼本発明は、水面積負荷と流出水の浮遊物濃度の関係を示す１式を利用して、流出水を沈澱槽に供給するか、汚泥濃縮設備に供給するか選択して処理するので、浮遊物濃度の高い流出水が沈澱槽に供給されて、処理水の水質を悪化させることがなく、しかも沈澱槽が有効活用される。
また、浮遊物濃度の低い流出水が汚泥濃縮設備に供給されることがないので、汚泥濃縮設備規模の縮小を図り、汚泥濃縮設備の有効活用を図ることが出来る。
▲２▼本発明は、逆洗洗浄時に水面積負荷と剥離汚泥の浮遊物濃度の関係を示す１式を利用して、剥離汚泥を沈澱槽（23）に供給するか、汚泥濃縮設備に供給するか選択して処理するので、浮遊物濃度の高い剥離汚泥が沈澱槽に供給されて、処理水の水質を悪化させることがなく、しかも沈澱槽が有効活用される。
また、浮遊物濃度の低い流出水が汚泥濃縮設備に供給されることがないので、汚泥濃縮設備規模の縮小を図り、汚泥濃縮設備の有効活用を図ることが出来る。
▲３▼通常運転時や逆洗洗浄時において、接触酸化槽の流出水や剥離汚泥の浮遊物濃度に応じて、予備試験結果に基づいて流出水や剥離汚泥に凝集剤を添加した後、固液分離することにより、流出水中の微細フロックを沈澱させて、処理水の水質の向上を図ることが出来ると共に、沈澱槽が有効活用される。
▲４▼本発明において、返送汚泥による浮遊微生物と接触材に固定された固定微生物とにより生物処理する場合には、既存装置を改造して処理能力を増加させることにより、廃水の性状変動や流量変動による有機性汚濁物質の負荷量の変動があっても容易に対応することが出来る。
また、装置を処理能力を増加させることが出来るので、新設装置をコンパクト化することが出来るから、建設用地を少なくすることが出来る。
▲５▼浮遊微生物の吸着力により微細フロックや浮遊物を吸着し、処理水水質の向上を図ることが出来るので、水質を向上することが出来ると共に、凝集剤の添加を必要なくするか、凝集剤の添加量を減少させることも出来る。
【図面の簡単な説明】
【図１】本発明のフローシート（第１の実施例）である。
【図２】通常運転時の接触酸化槽の流出水に凝集剤を添加した場合の、処理水の浮遊物濃度と凝集剤添加量の関係を示す図である。
【図３】通常運転時の接触酸化槽の流出水に凝集剤を添加した場合の、流出水の浮遊物濃度と凝集剤添加量の関係を示す図である。
【図４】逆洗洗浄時の接触酸化槽の流出水に凝集剤を添加した場合の、処理水の浮遊物濃度と凝集剤添加量の関係を示す図である。
【図５】逆洗洗浄時の接触酸化槽の流出水に凝集剤を添加した場合の、流出水の浮遊物濃度と凝集剤添加量の関係を示す図である。
【図６】流出水の浮遊物濃度と水面積負荷の関係を示す図である。
【図７】本発明のフローシート（第２の実施例）である。
【図８】従来法のフローシートである。
【符号の説明】
１本発明の最初沈澱槽 21 従来法の最初沈澱槽
２〃接触酸化槽 22 〃接触酸化槽
３〃沈澱槽 23 〃沈澱槽
４〃初沈汚泥貯留槽 24 〃初沈汚泥貯留槽
５〃汚泥濃縮設備 25 〃汚泥濃縮設備
６〃演算制御器 28 〃接触材
７〃凝集剤供給機
８〃接触材
９〃返送汚泥経路[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a method for catalytic oxidation of wastewater in which wastewater such as human waste and sewage is biologically treated in an aerobic environment in a contact oxidation tank filled with a contact material.
[0002]
[Prior art]
The contact oxidation method is a treatment method in which a biofilm containing microorganisms is attached to the surface of a contact material filled and immersed in a contact oxidation tank, and is contacted with wastewater under aerobic conditions to perform biological treatment. Widely used in the field of wastewater treatment and sewage treatment.
As shown in FIG. 8, in the conventional catalytic oxidation method (conventional method), the waste water separated from the first settling sludge in the first precipitation tank (21) is separated into the contact oxidation tank (22) provided with the contact material (28). ), And contact oxidation (biological treatment) is performed by the biofilm attached to the surface of the contact material (28), and the first settling sludge is stored in the first settling sludge storage tank (24), and then the gravity concentration tank and levitation Supplied to sludge concentration equipment (25) such as concentration tank and centrifugal concentrator.
During normal operation, when the biofilm produced by this biological treatment exceeds the specified thickness, it will be peeled off little by little, and part of the peeled sludge that has been naturally peeled becomes fine flocs and floats in the contact oxidation tank (22). The remainder of the precipitate settles at the bottom of the catalytic oxidation tank (22).
[0003]
During normal operation of the conventional method (contact oxidation method using fixed microorganisms fixed to the contact material), all the effluent water from the contact oxidation tank (22) is supplied to the precipitation tank (23) and separated into solid and liquid.
The suspended matter concentration of the effluent during normal operation is, for example, 20 to 100 mg / l (liter), and the treated water separated into solid and liquid in the sedimentation tank (23) is usually treated water quality (suspended matter concentration, turbidity). However, the fine flocs of the effluent are not easily settled and are accompanied by the treated water as they are, which may deteriorate the quality of the treated water.
The treated water that has been solid-liquid separated in the settling tank (23) flows out from the upper part of the settling tank (23), and the sludge settles to the lower part to become excess sludge.
When the biofilm attached to the surface of the contact material (28) reaches a predetermined thickness or more during normal operation, the biofilm is spontaneously peeled off little by little, but the timing varies depending on the properties of the wastewater and the treatment amount. When a large amount of natural detachment of the biofilm occurs temporarily, the suspended matter concentration of the effluent from the contact oxidation tank (22) becomes high, and the treated water is not completely separated in the precipitation tank (23). In some cases, the water quality was further deteriorated.
[0004]
In the contact oxidation method, a contact material (28) is provided in the contact oxidation tank (22), and a biofilm is formed on the surface of the contact material (28) to perform contact oxidation treatment. A biofilm grows on the surface, filling the gap between the contact material (28) and the contact material (28).
As the elapsed time of the contact oxidation treatment becomes longer, the wastewater flow path becomes clogged, and the wastewater does not flow evenly across the entire waterway between the contact materials, but flows only through specific flow paths. Insufficient contact with water and insufficient oxygen supply may result in insufficient biological treatment of wastewater within a predetermined time.
In order to eliminate the blockage of the flow path of the waste water contact oxidation tank (22) as described above, backwashing is performed. When backwash air is sprayed for 5 to 20 minutes from directly under the contact material (28) provided on the top of the exfoliated sludge that has settled on the bottom during backwash cleaning, the biofilm is forcibly separated from the contact material (28). Thus, a part of the exfoliated sludge floats in the contact oxidation tank (22) and flows out along with the effluent water, and the remaining part is deposited as exfoliation sludge at the bottom of the contact oxidation tank (22).
[0005]
During normal operation, natural exfoliation sludge is generally not extracted from the bottom of the contact oxidation tank (22), so natural exfoliation with a high suspended solids concentration at the bottom of the contact oxidation tank (22) after continuing normal operation. Sludge is settled. Although it depends on the frequency of backwashing and the number of tanks in the contact oxidation tank (22), a large amount of the biofilm in the contact oxidation tank (22) is forcibly separated during backwashing, and the suspended matter concentration is in the range of several thousand to 20,000 mg / l. To reach.
The concentration of suspended matter in the effluent accompanying the exfoliated sludge in the upper part of the contact oxidation tank (22) gradually decreases with time. If this is continuously supplied to the sludge concentration facility (25), the suspended matter concentration will increase. Low effluent water was supplied to the sludge concentration facility (25), and it was necessary to increase the scale of the sludge concentration facility (25).
[0006]
At the time of backwashing by the conventional method, there is no problem even if the exfoliated sludge is supplied to the sludge concentration facility (25) because the suspended matter concentration is high at an early stage after the start of backwashing.
However, if the exfoliation sludge from the bottom of the contact oxidation tank (22) continues to be pulled out by the pump, the exfoliation sludge concentration in the exfoliation sludge gradually decreases, and exfoliation sludge with a low flotation concentration is supplied to the sludge concentration facility (25). Therefore, it was necessary to increase the scale of the sludge concentration facility (25), which was a problem.
For this reason, if the supply of effluent water or exfoliated sludge to the sludge concentrating facility (25) is stopped early and then supplied to the sedimentation tank (23), the effluent with a high suspended matter concentration will be caused by fluctuations in the floating sludge concentration of the exfoliated sludge. Water and exfoliated sludge will be supplied, exceeding the solid-liquid separation capacity of the sedimentation tank (23), which has the problem of deteriorating the quality of the treated water (floating matter concentration, turbidity, etc.) .
[0007]
In a single contact oxidation tank (22), it is possible to estimate the change in suspended solids concentration over time after backwashing to some extent, but multiple contact oxidation tanks (22) are provided in series. If so, the wastewater flows from the upstream contact oxidation tank (22) to the downstream contact oxidation tank (22). Since the effluent is diluted with the effluent, the concentration of suspended matter in the effluent supplied to the sedimentation tank (23) is low at the beginning with the passage of time after backwashing, and gradually increases due to the influence of the exfoliated sludge. Moreover, it becomes low. Moreover, the suspended solid concentration of the exfoliated sludge to be extracted also becomes high with the passage of time but gradually becomes low.
Therefore, depending on which position the contact oxidation tank (22) is backwashed, the degree to which the exfoliated sludge mixed in the backwashing is mixed will vary. It was particularly difficult to predict how the suspended matter concentration of water would fluctuate when multiple contact oxidation tanks (22) were provided in series.
[0008]
In other words, in the conventional method, sedimentation that combines the flow rate and flow rate of the effluent that flows out from the upper part of the contact oxidation tank (22) after backwashing and the separated sludge drawn from the lower part of the contact oxidation tank (22). Considering the level of water area load on the tank (23), the person in charge does not control the supply of spilled water or exfoliated sludge to the sedimentation tank (23). Based on experience, the suspended solid concentration in the sludge is supplied to the sedimentation tank (23) or sludge concentration facility (25).
Therefore, as described above, when effluent with high suspended solids concentration or exfoliated sludge is supplied to the sedimentation tank (23), the solid-liquid separation capacity of the sedimentation tank (23) is exceeded, and the quality of the treated water ( When sludge concentration equipment (25) is deteriorated, or when effluent or flakes with low suspended matter concentration are supplied to sludge concentration equipment (25), sludge concentration equipment (25) is excessively large. There was a problem with the equipment.
Without considering the water area load on the sedimentation tank (23) as in the conventional method, the sedimentation tank (23) is determined based on the visual inspection of the person in charge of the effluent and exfoliated sludge. And the sludge concentration facility (25), it is difficult to effectively utilize the processing capacity of the sedimentation tank (23) and sludge concentration facility (25).
[0009]
When a contact oxidizer is constructed at a human waste treatment plant or a sewage treatment plant, the organic pollutant is the product of the organic pollutant concentration of wastewater (eg BOD, COD, TOC concentration, UV absorbance, etc.) and the flow rate. The contact material (28) necessary for the contact oxidation treatment is filled in accordance with the load amount (for example, the BOD load amount in the case of the product of BOD concentration and flow rate), and fixed to the contact material (28). Biological treatment can be carried out by the fixed microorganisms of the biofilm.
However, after the construction of the above-mentioned catalytic oxidizer, if the amount of water and BOD load increase significantly compared to the original plan, the number of fixed microorganisms becomes insufficient and biological treatment becomes difficult. Securing additional land is a serious problem because it is difficult in urban areas.
For this reason, it is required to reduce the construction site by modifying the existing equipment to increase the processing capacity or downsizing the new equipment.
[0010]
In the conventional method, when flocculant is not added to the effluent of the contact oxidation tank (22), fine flocs do not easily settle in the precipitation tank (23), and are directly accompanied by treated water. The water quality could be deteriorated.
In addition, even when adding the flocculant, the addition amount is fixed, or it was added appropriately at the judgment of the person in charge, so the optimum addition was not made and the necessary and sufficient solid-liquid separation could not be made. Therefore, the cost of the flocculant is increased, and a more appropriate method for adding the flocculant has been demanded.
[0011]
[Problems to be solved by the invention]
The present invention has been made against the background of the above circumstances, and in the wastewater catalytic oxidation method, it is possible to prevent the quality of the treated water from deteriorating due to the supply of effluent or exfoliated sludge having a high suspended solids concentration to the settling tank. At the same time, the effluent water with low suspended solids concentration and exfoliated sludge are supplied to the sludge concentrating equipment, and the sludge concentrating equipment is prevented from increasing, thereby effectively utilizing the sedimentation tank and reducing the scale of the sludge concentrating equipment. Is an issue.
Another object is to make the catalytic oxidation apparatus compact and increase the processing capacity.
Furthermore, it is an object to further improve the quality of treated water by removing fine flocs and suspended solids by adding an appropriate amount of flocculant.
[0012]
[Means for solving the problems]
The first invention of the present invention is a contact oxidation method for wastewater, which is obtained by subjecting effluent after contact oxidation in a contact oxidation tank filled with a contact material to solid-liquid separation in a precipitation tank to be treated. The coefficient k, a, b, c of the following equation (1), which is a relational expression between the suspended water concentration of the contact oxidation tank and the water area load of the sedimentation tank, is obtained by a preliminary test, and the effluent water temperature, SVI, And the calculated value of the suspended matter suspended matter concentration obtained by substituting the measured value of the water area load into the formula 1, and the measured value of the suspended matter suspended matter concentration, the measured value is If the calculated value is less than or equal to the calculated value, the effluent from the contact oxidation tank is supplied to the sedimentation tank for solid-liquid separation, and if the measured value exceeds the calculated value, the effluent from the contact oxidation tank is sludged. This is a catalytic oxidation method for wastewater, which is supplied to a concentrating facility and concentrated.

[0013]
According to a second invention, in the contact oxidation method of waste water, the effluent after the waste water is subjected to the contact oxidation treatment in the contact oxidation tank filled with the contact material is separated into solid and liquid in the precipitation tank to be treated water. The coefficient k, a, b, c of the following equation (1), which is a relational expression between the suspended matter concentration of the effluent and the load on the sedimentation tank, is obtained through preliminary tests, and the effluent water temperature, SVI, and floating The calculated value of the effluent water area load obtained by substituting the measured value of the substance concentration into the set is compared with the measured value of the effluent water area load, and the measured value is the calculated value. In the following cases, the effluent from the contact oxidation tank is supplied to a precipitation tank for solid-liquid separation, and when the measured value exceeds the calculated value, the effluent from the contact oxidation tank is sent to a sludge concentrating facility. It is a catalytic oxidation method of wastewater characterized by supplying and concentrating.

[0014]
In a third invention, in the first or second invention, when the flocculant is added to the effluent water having a different floating substance concentration and solid-liquid separation is performed, the floating substance concentration of the treated water can be maintained below the target value. A calibration curve between the amount of added agent and the suspended solids concentration is obtained by a preliminary test. Using this calibration curve, a flocculant is added according to the suspended matter concentration in the effluent, and then solid-liquid separation is performed in the sedimentation tank. This is a catalytic oxidation method for wastewater.
[0015]
4th invention is the contact oxidation tank in the waste water contact oxidation method which uses solid-liquid separation of the effluent after carrying out contact oxidation treatment of the wastewater in the contact oxidation tank filled with the contact material as a treated water. The coefficient k, a, b, c of the following equation (1), which is a relational expression between the suspended sludge concentration of the exfoliated sludge and the water area load of the sedimentation tank, is obtained by preliminary tests, and the water temperature, SVI, and water area of the exfoliated sludge Compare the measured value of the floating sludge concentration of the exfoliated sludge obtained by substituting the measured value of the load into the set, and the measured value of the floating sludge concentration of the exfoliated sludge. In this case, the separation sludge from the contact oxidation tank is supplied to a sedimentation tank for solid-liquid separation, and when the measured value exceeds the calculated value, the separation sludge from the contact oxidation tank is supplied to a sludge concentration facility. It is a catalytic oxidation method of wastewater characterized by supplying and concentrating.

[0016]
5th invention is the contact oxidation tank in the waste water contact oxidation method which uses solid-liquid separation of the effluent after carrying out contact oxidation treatment of the wastewater in the contact oxidation tank filled with the contact material as a treated water The coefficient k, a, b, c of the following equation (1), which is the relational expression between the concentration of suspended sludge in the sludge and the water area load of the sedimentation tank, is obtained by preliminary tests, and the water temperature, SVI, and suspended solids of the separated sludge Comparing the measured value of the peeled sludge water area load obtained by substituting the measured value of the concentration into the formula, and the measured value of the peeled sludge water area load, the measured value is less than the calculated value In this case, the separation sludge from the contact oxidation tank is supplied to the sedimentation tank for solid-liquid separation. If the measured value exceeds the calculated value, the separation sludge from the contact oxidation tank is supplied to the sludge concentration equipment. It is a catalytic oxidation method of wastewater characterized by being concentrated.

[0017]
6th invention is the 4th or 5th invention, the aggregation which can maintain the suspended solid density | concentration of a treated water below a target value, when adding a flocculant to the peeling sludge of different suspended solid density and carrying out solid-liquid separation. A calibration curve between the amount of added agent and the suspended sludge concentration in the sludge is obtained by a preliminary test. Using this calibration curve, a flocculant is added according to the suspended sludge concentration in the separated sludge, and then solid-liquid separation is performed in the precipitation tank. This is a catalytic oxidation method for wastewater.
[0018]
7th invention returns a part of sludge solid-liquid-separated by the precipitation tank to a contact oxidation tank as return sludge, The contact oxidation of the wastewater as described in any one of the 1st-6th invention characterized by the above-mentioned Is the law.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
The embodiment of the present invention will be described with respect to the first example shown in FIG. 1 (contact oxidation method using a fixed microorganism fixed to a contact material).
During normal operation, waste water flowing out after solid-liquid separation in the first sedimentation tank (1) is supplied to the contact oxidation tank (2) filled with the contact material (8), and the lower part of the first precipitation tank (1). The first settling sludge settled in the tank is stored in the first settling sludge storage tank (4) and then supplied to the sludge concentration facility (5).
The waste water that has flowed into the contact oxidation tank (2) filled with the contact material (8) is biologically treated by the action of the biofilm attached to the surface of the contact material (8).
The biofilm that gradually grows by biological treatment peels off naturally from the contact material (8) when it reaches a predetermined thickness, settles as a stripped sludge on the bottom of the contact oxidation tank (2), and a part of it becomes a fine floc in the tank It floats in the water and eventually flows into the sedimentation tank (3) along with the effluent water. In the contact oxidation tank (2), a string-like contact material, for example, a ring lace (registered trademark) manufactured by Japan Industrial Machinery Co., Ltd., a net-like contact material, for example, Hettimalon (registered trademark) made by Shinko Nylon, a bio-made by Toray A contact material (8) having many voids is filled in a contact material such as Comb (registered trademark).
[0020]
During normal operation of the first embodiment, the suspended matter concentration of the effluent water is relatively low, for example, 20 to 100 mg / l (liter), and its fluctuation range is also small. There are few troubles.
However, during backwashing, the concentration of effluent during backwashing and the concentration of suspended sludge in the backwashing varies considerably depending on the position of the contact oxidation tank (2) for backwashing and the frequency of backwashing. When the person in charge visually observes the sludge and the peeled sludge, the person in charge appropriately supplies it to the sedimentation tank or supplies it to the sludge concentrating equipment.
The present invention relates to the suspended matter concentration and water area load (m ^Three / M ² / Day) Using one set showing the relationship, select whether to supply effluent water or exfoliated sludge to the sedimentation tank (3) or to the sludge concentration facility, depending on the load on the sedimentation tank (3) In particular, this is an effective method for backwash cleaning.
[0021]
The method of the present invention will be described below based on the first embodiment.
Water area load (m ^Three / M ² / Day) is the flow rate (m ^Three / Day), the effective surface area of the precipitation tank (m ² ) Divided by. The removal rate of suspended solids in the sedimentation tank is proportional to the surface area of the sedimentation tank and the sedimentation rate of the sludge particles, and inversely proportional to the flow rate of the waste water.
Therefore, the water area load obtained by dividing the flow rate of waste water by the surface area of the precipitation tank is an important design specification for determining the removal rate of the suspended matter in the precipitation tank.
In order to perform solid-liquid separation within the residence time in the settling tank, it is necessary to make the water area load of the settling tank (the rising flow rate of the effluent water) smaller than the settling speed of the sludge particles, and the sludge particles are relatively It is necessary to settle at a different settling rate and arrive at the bottom of the settling tank within the residence time. The necessary water area load is determined from both.
By analyzing the test data by nonlinear regression analysis (Powell method), the water area load can be expressed as a function of water temperature, suspended solids concentration and SVI.
M = k · T ^a ・ N ^-b ・ (SVI) ^-c .... 1 set
Here, the coefficients k, a, b, and c are coefficients that vary depending on the properties of the waste water and the properties of the sludge, and are determined by a preliminary test.
For example, the coefficients k, a, b, and c are defined by the following two formulas for activated sludge in sewage treatment.

If a preliminary test cannot be performed at the start of the test due to circumstances, sewage should be treated tentatively using the above factors, and more appropriate when the test data of the target effluent is accumulated. The coefficients k, a, b, and c may be changed.
It is preferable to use measured values for each of the effluent water temperature, SVI, flow rate, water area load, suspended matter concentration, etc., but each value can also be set based on existing data.
Substituting the coefficients k, a, b, c, waste water temperature, and SVI in Equation 2, the water area load is expressed as a function of the suspended matter concentration of the waste water. The suspended solids concentration corresponding to the water area load can be obtained by calculation.
In addition, SVI (sludge capacity index) is an index that indicates the volume occupied by 1 g of sludge when the sludge is allowed to stand in a container for 30 minutes, and indicates the quality of sludge sedimentation. Since it is not a factor that fluctuates by the unit of time, the latest measured value can be substituted.
Compared with the case where the SVI of the effluent water is 100, when the SVI is 120, the solid-liquid separation is difficult, and thus the suspended matter concentration that can be supplied to the precipitation tank is lower.
[0022]
Here, when the coefficients k, a, b, and c are obtained by a preliminary test and a relational expression such as equation (2) is obtained, if the effluent water temperature is 20 ° C. and the SVI is 120, the effluent water A method for selecting whether to supply to a sedimentation tank or to a sludge concentration facility will be described. Substituting effluent SVI = 120 and water temperature = 20 ° C. into the two formulas obtained from the preliminary test for the effluent of the sewage contact oxidation tank, and the flow rate (m ^Three / Day), the effective surface area of the precipitation tank (m ² Substituting the water area load M2 divided by), the calculated value N2 of the suspended water suspended matter concentration corresponding to the water area load M2 is obtained, and from this, the coordinate point Q (M2, N2) is determined, like this When a simple calculation is performed, a curve as shown in FIG. 6 is drawn.
Here, assuming that the temperature of the effluent water to be sorted obtained by measurement = 20 ° C., SVI = 120, water area load = M2, and suspended matter concentration = N1, point P (M2, N1) on FIG. The measured value N1 of suspended water effluent concentration for water area load = M2 is smaller than the calculated value N2, and the point P is in the lower region of the curve SVI = 120, so the precipitation tank (3) It is determined that solid-liquid separation is possible in step (b), and the effluent is supplied to the settling tank (3). On the other hand, assuming that the temperature of the effluent water to be sorted obtained by measurement = 20 ° C., SVI = 120, water area load = M2, and the measured value of suspended solids = N3, it is represented as point R (M2, N3). However, since the measured value N3 of the suspended water concentration for the water area load = M2 is larger than the calculated value N2, and the point R is in the upper region of the curve SVI = 120, the solid liquid in the precipitation tank (3) It is judged that separation is impossible, and the effluent is supplied to the sludge concentration facility (5).
For exfoliated sludge, a preliminary test can be carried out in the same way as the effluent during backwashing and treated in the same way, but if both are similar in properties, the preliminary test The results can be applied mutatis mutandis.
[0023]
As mentioned above, when it exists in the lower area | region of the curve which shows the relationship between the suspended solid density | concentration of effluent water and a water area load, effluent water is stably solid-liquid-separated by a sedimentation tank (3).
In addition, when adding a flocculant to effluent, since the solid-liquid separation capability in a precipitation tank (3) improves, the flow volume of the effluent which can be processed with a precipitation tank (3) increases.
Therefore, the solid-liquid separation capability of the sedimentation tank (3) can be effectively utilized, and the scale of the sludge concentration facility (5) can be reduced.
On the other hand, when it is in the upper region of the curve showing the relationship between the suspended solid concentration and the water area load, it is supplied to the sludge concentration facility (5), concentrated as necessary, and sent to the sludge treatment facility. It is done.
[0024]
At the beginning of operation, the above sort is performed by the relational expression calculated by the provisionally set coefficients k, a, b, c. After such sort, the treated water from the settling tank (3) is used. It is necessary to measure the water quality of the water and investigate whether the water quality satisfies the standard value.
If such a survey is continued throughout the year, data is accumulated. Therefore, it is possible to perform better control than by feeding back the accumulated data and setting new coefficients k, a, b, and c.
The person in charge visually determines the effluent containing the exfoliated sludge that varies depending on the position of the contact oxidation tank (22) for backwashing and the frequency of backwashing, etc. Compared with the conventional method in which sludge is extracted and the sedimentation tank (23) or sludge concentrating equipment (25) is selected and supplied, the method of the present invention has a suspended matter concentration (mg / l) of effluent and exfoliated sludge. Water area load (m) of settling tank (3) ^Three / M ² / Day) to select whether to supply effluent water or exfoliated sludge to the sedimentation tank (3) or to supply sludge concentrating equipment (5). Even if the concentration fluctuates, accurate and stable processing can be performed.
In the above example, when the capacity of solid-liquid separation of the sedimentation tank (3) was exceeded using the water area load and suspended solids as an index, the entire amount was supplied to the sludge concentration facility (5). The exfoliated sludge can also be distributed to the settling tank (3) and the sludge concentration facility (5). That is, a method in which a part of the effluent water is supplied to the sedimentation tank (3) so that the solid-liquid separation can be performed in the precipitation tank (3), and the front part exceeding the solid-liquid separation capacity is supplied to the sludge concentration facility (5). It is. This method has the advantage that the sedimentation tank (3) can be used more effectively, although the control is slightly complicated.
In the present invention, the concentration of suspended solids and the water area load for changing the treatment method are classified into cases where it is less than a predetermined value and cases where it is exceeded. These are the same and are also included in the present invention.
[0025]
In the above example, the water area load was substituted first, and either the supply of the effluent water to the sedimentation tank (3) or the supply of the sludge concentration facility (5) by the suspended matter concentration was selected. As another method, it is also possible to select whether to supply the effluent water to the sedimentation tank (3) or to the sludge concentration facility (5) by substituting the suspended solid concentration first, depending on the water area load.
As a control method, if the water temperature of the effluent to be sorted obtained by measurement = 20 ° C., SVI = 120, water area load = M1, and suspended matter concentration = N2, the point S (M1 in FIG. , N2), but the measured value M1 of the effluent water area load for suspended matter concentration = N2 is smaller than the calculated value M2, and the point S is in the lower region of the curve SVI = 120, so the settling tank In (3), it is judged that solid-liquid separation is possible, and the effluent is supplied to the settling tank.
On the other hand, the water temperature of the effluent to be sorted obtained by the measurement = 20 ° C., SVI = 120, the water area load = M4, and the measured value of the suspended solids = N2; , N2), the measured value M4 of the effluent water area load for suspended matter concentration = N2 is greater than the calculated value M2, and the point T is in the upper region of the curve SVI = 120, so the settling tank ( In 3), it is judged that solid-liquid separation is impossible, and the effluent is supplied to the sludge concentration facility (5).
Water area load (m ^Three / M ² / Day) is the flow rate (m ^Three / Day) is the effective surface area of the precipitation tank (m ² Therefore, selecting by the water area load is substantially the same as selecting by the flow rate, and the effluent is supplied to the sedimentation tank (3) by the flow rate or the sludge concentration facility ( It is also possible to select whether to supply to 5).
[0026]
The first embodiment (contact oxidation method using immobilized microorganisms fixed to a contact material) has been described. The filling amount of the contact material (8) filled in the contact oxidation tank (2) is determined according to design conditions. Since the specific surface area of the contact material (8) is fixed, the amount of microorganisms fixed to the contact material (8) is naturally limited, and the processing capacity per volume is fixed. . Therefore, it cannot be easily dealt with if there is a change in the load of organic pollutant due to fluctuations in the properties or flow rate of wastewater.
For this reason, a catalytic oxidation method was developed, which uses both fixed microorganisms fixed to the contact material and suspended microorganisms by return sludge.
According to this method in which the amount of microorganisms is increased, it is possible to easily cope with the increase and fluctuation of the load without changing the size of the device, so that the size of the device can be made compact.
The second embodiment of the present invention (contact oxidation method using fixed microorganisms fixed to a contact material and suspended microorganisms by return sludge) will be described below.
[0027]
As shown in FIG. 7, the contact oxidation method of the second embodiment requires the return sludge in the contact oxidation tank (2) filled with the contact material (8) in the contact oxidation method of the first embodiment. For example, a step of returning 20 to 50% according to the microbial concentration is added.
Since the organic pollutant concentration in the wastewater is higher as it goes upstream, which is the inflow side of the wastewater, the clogging between the contact materials (8) tends to occur more easily as it goes upstream.
The return position of the return sludge is returned to the latter stage (for example, the third stage) where the microorganism concentration is insufficient and the microorganism concentration is low without returning the return sludge to the first stage where the microorganism concentration is high, if the amount of microorganisms is satisfied. It is preferred to distribute and return the sludge to increase the microbial concentration.
In the second embodiment in which the return sludge is returned, the suspended matter concentration of the effluent of the contact oxidation tank (2) is as high as 1000 to 2000 mg / l, for example, and this value is added during backwash cleaning. Therefore, it is important to select whether to supply to the sedimentation tank (3) or to the sludge concentration facility (5) according to the suspended matter concentration and water area load of the effluent.
In addition, the presence or absence of clogging of the contact oxidation tank (2) is generally determined by visually observing the thickness of the biofilm of the test piece that can be taken out, or by anaerobic floating sludge with a blackish taste in the tank. Judgment is made by visually observing whether or not there is an odor.
[0028]
The contact oxidation method of the second embodiment is a method of biological treatment with fixed microorganisms fixed to the contact material and suspended microorganisms by return sludge, and the fixed microorganism fixed to the contact material in the contact oxidation tank (2). Compared with the contact oxidation method of the first embodiment in which the biological treatment is carried out only by the amount of microorganisms, the amount of microorganisms in the contact oxidation tank can be increased. Since it is a method that can reduce the size of the apparatus if it is a load, it is preferable because it can reduce the land area required for new installation or expansion.
[0029]
In the contact oxidation method of the first embodiment, a part of the exfoliated sludge that naturally exfoliated from the biofilm flows into the sedimentation tank as it is accompanied by the effluent as fine flocs of several tens of μm or less, and is removed there. The treated water quality may be deteriorated.
In the contact oxidation method of the second embodiment, since the return sludge is returned, the fine floc in the contact oxidation tank (2) is almost adsorbed by the adsorbing action of floating microorganisms mainly composed of aerobic bacteria, Since it becomes a large floc of several hundreds of μm that easily settles, it is easily precipitated and separated into a solid and a liquid in a precipitation tank.
There is an advantage that it is not necessary to add a flocculant to the effluent to remove fine flocs, or even if a flocculant is added, the amount of flocculant added can be greatly reduced.
[0030]
In order to make it easier for solid-liquid separation of the effluent supplied to the settling tank (3) during backwashing, the suspended matter concentration of treated water during backwashing shown in FIG. 4 was determined by another preliminary test. The flocculant is added to the effluent using the relationship between the amount of flocculant added and the amount of suspended matter and the amount of flocculant added during backwashing washing shown in FIG. It is preferable to be supplied to 3).
Next, the addition method in the case of adding a flocculant to effluent water and exfoliation sludge is demonstrated.
In order to determine the amount of flocculant added to the effluent of the contact oxidation tank (2) during normal operation of the first embodiment, for example, as shown in FIG. A flocculant (for example, an inorganic flocculant PAC) is added to the effluent water having various concentrations of suspended solids, and a diagram showing the relationship between the suspended solid concentration of the treated water after the precipitation treatment and the amount of flocculant added.
[0031]
Fig. 2 shows that the suspended matter concentration of treated water is further reduced when 20-40 mg / l of flocculant is added to the effluent of the sewage contact oxidation tank (2) having a suspended matter concentration of 18-52 mg / l. It shows that
If the amount of flocculant added is increased or decreased according to the suspended matter concentration of the effluent water, the water quality target for treated water can be satisfied effectively and economically.
In the present invention, the effluent of the contact oxidation tank (2) containing fine flocs during normal operation is measured for the suspended matter concentration and flow rate, and the dry solids amount of the effluent is calculated and controlled from the measured suspended matter concentration and flow rate. The suspended matter concentration of the treated water set by the preliminary test is maintained below a predetermined target value based on the signal from the calculation controller (6). A calibration curve between the obtained amount of the flocculant added and the suspended solid concentration of the effluent water is obtained by a preliminary test, and a predetermined amount of the flocculant is added by the flocculant feeder (7).
The effluent water after the addition of a predetermined amount of the flocculant flows into the sedimentation tank (3), and is solid-liquid separated into treated water and sludge (excess sludge) in the sedimentation tank (3). In the method for catalytic oxidation of wastewater according to the present invention, since the flocculant is added, the fine floc is almost completely solid-liquid separated.
From the above data, for example, if the target value of the suspended matter concentration of the treated water is 10 mg / l or less, the relationship between the suspended matter concentration of the effluent and the added amount of the flocculant as shown in FIG. 3 is shown. A calibration curve is created, and the amount of flocculant added to the suspended matter concentration of the effluent is determined by this calibration curve.
[0032]
The suspended matter concentration of the treated water after being precipitated in the precipitation tank (3) is measured continuously or intermittently by the arithmetic and control unit (6). The measured suspended concentration of treated water is fed back, and the relationship between the suspended matter concentration of the effluent, the amount of flocculant added, and the suspended concentration of treated water obtained in the preliminary test is corrected, and more appropriate flocculant added. The amount will be set anew. Since the human waste treatment plant and the sewage treatment plant are always operated, it is possible to control more accurately by accumulating such data.
In addition, since there is a correlation between the suspended matter concentration and turbidity of the effluent of the contact oxidation tank (2), the same control can be performed using the turbidity instead of the suspended matter concentration. . Since flocculant is added according to the suspended matter concentration of the effluent of the contact oxidation tank (2), compared to the case where no flocculant is added as in the conventional method, the fine flocs are easily separated into solid and liquid, The quality of the treated water flowing out of the settling tank (3) is greatly improved.
The sludge precipitated at the bottom of the settling tank (3) is supplied to the sludge concentration facility (5), where it is concentrated and then supplied to a sludge treatment facility such as a vacuum dehydrator or a sludge incinerator for processing. .
[0033]
Determination of the amount of flocculant added to the effluent of the contact oxidation tank (2) containing a large amount of exfoliated sludge during backwashing can be determined in substantially the same manner as during normal operation.
For example, as shown in FIG. 4, a flocculant (for example, an inorganic flocculant PAC) is added to the effluent having different suspended matter concentrations in the contact oxidation tank (2) in which sewage is contact-oxidized, and the treated water after the precipitation treatment is added. A diagram showing the relationship between the suspended matter concentration and the amount of flocculant added is created.
Figure 4 shows that the suspended matter concentration of treated water is further reduced when the flocculant is precipitated after adding 70 to 150 mg / l of the effluent of the sewage contact oxidation tank (2) having a suspended matter concentration of 2000 to 4000 mg / l. It shows that
If the flocculant addition amount is increased or decreased according to the suspended matter concentration of the effluent water, it is possible to cope with changes in the target concentration of treated water.
[0034]
The suspended matter concentration of the effluent of the contact oxidation tank (2) is measured continuously or intermittently by the arithmetic controller (6). Depending on the measured suspended solid concentration, average suspended solid concentration, etc., the amount of flocculant added that satisfies the target concentration of suspended solids in the treated water is determined using the relationship between the suspended solid concentration and the added amount of flocculant. A predetermined amount of the flocculant calculated based on the signal is added by the flocculant supply machine (7).
The flocculant is added to the effluent of the contact oxidation tank (2), and the suspended matter concentration of the treated water after being precipitated in the precipitation tank (3) is measured continuously or intermittently by the arithmetic controller (6). However, if these suspended matter concentrations are not the desired concentration, this result is fed back and the relationship between the suspended matter concentration of the effluent, the amount of flocculant added, and the suspended matter concentration of the treated water obtained in the preliminary test is fed back. Is corrected and a more appropriate addition amount is preferably set. The method for controlling the exfoliated sludge can be the same as in the case of the outflow water.
[0035]
【The invention's effect】
(1) The present invention uses one set showing the relationship between the load on the water area and the suspended solids concentration to select whether to supply the effluent to the sedimentation tank or to the sludge concentration facility. Therefore, effluent with high suspended solids concentration is supplied to the sedimentation tank, and the quality of the treated water is not deteriorated, and the sedimentation tank is effectively used.
Moreover, since effluent with low suspended solids concentration is not supplied to the sludge concentration facility, the scale of the sludge concentration facility can be reduced, and the sludge concentration facility can be effectively utilized.
(2) The present invention uses one set showing the relationship between the water area load and the concentration of the suspended sludge suspended matter during backwashing to supply the separated sludge to the sedimentation tank (23) or to the sludge concentration facility. Since it is selected and processed, exfoliated sludge having a high suspended matter concentration is supplied to the sedimentation tank, so that the quality of the treated water is not deteriorated and the sedimentation tank is effectively utilized.
Moreover, since effluent with low suspended solids concentration is not supplied to the sludge concentration facility, the scale of the sludge concentration facility can be reduced, and the sludge concentration facility can be effectively utilized.
(3) During normal operation or backwashing, after adding flocculant to the effluent and the exfoliated sludge based on the preliminary test results according to the concentration of the effluent of the contact oxidation tank and exfoliated sludge, By separating the liquid, fine flocs in the effluent can be precipitated to improve the quality of the treated water, and the precipitation tank is effectively used.
(4) In the present invention, when biological treatment is carried out with suspended microorganisms by return sludge and fixed microorganisms fixed to the contact material, the existing equipment is modified to increase the treatment capacity, thereby changing the wastewater properties and flow rate. Even if the load of organic pollutants varies due to fluctuations, it can be easily handled.
Moreover, since the processing capacity of the apparatus can be increased, the new apparatus can be made compact, so that the construction site can be reduced.
(5) Adsorbing fine flocs and suspended solids by the adsorbing power of floating microorganisms and improving the quality of treated water can improve the water quality and eliminate the need for adding a flocculant or agglomeration The additive amount of the agent can also be reduced.
[Brief description of the drawings]
FIG. 1 is a flow sheet (first embodiment) of the present invention.
FIG. 2 is a graph showing the relationship between the suspended solids concentration of treated water and the amount of flocculant added when flocculant is added to the effluent of the contact oxidation tank during normal operation.
FIG. 3 is a graph showing the relationship between the suspended solid concentration of the effluent and the amount of flocculant added when the flocculant is added to the effluent of the contact oxidation tank during normal operation.
FIG. 4 is a diagram showing the relationship between the suspended solids concentration of treated water and the amount of flocculant added when flocculant is added to the effluent of the contact oxidation tank during backwashing.
FIG. 5 is a diagram showing the relationship between the suspended solid concentration of the effluent and the amount of flocculant added when the flocculant is added to the effluent of the contact oxidation tank during backwashing.
FIG. 6 is a diagram showing the relationship between the suspended matter concentration of effluent water and the water area load.
FIG. 7 is a flow sheet (second embodiment) according to the present invention.
FIG. 8 is a conventional flow sheet.
[Explanation of symbols]
1 First Precipitation Tank of the Present Invention 21 First Precipitation Tank of Conventional Method
2 接触 Contact oxidation tank 22 接触 Contact oxidation tank
3〃 Precipitation tank 23〃 Precipitation tank
4 初 First settling sludge storage tank 24 初 First settling sludge storage tank
5 〃 Sludge concentration equipment 25 〃 Sludge concentration equipment
6 演算 Arithmetic controller 28 接触 Contact material
7 〃 Flocculant supply machine
8 〃 Contact material
9 経路 Return sludge route

Claims

廃水を接触材が充填された接触酸化槽で接触酸化処理した後の流出水を、沈澱槽で固液分離して処理水とする廃水の接触酸化法において、前記接触酸化槽の流出水の浮遊物濃度と沈澱槽の水面積負荷との関係式である下記の１式の係数ｋ，ａ，ｂ，ｃを予備試験により求めると共に、流出水の水温、ＳＶＩ、および水面積負荷の測定値を、１式に代入することにより得られた流出水の浮遊物濃度の計算値と、前記流出水の浮遊物濃度の測定値とを比較し、前記測定値が前記計算値以下の場合には、前記接触酸化槽の流出水を沈澱槽に供給して固液分離し、前記測定値が、前記計算値を越える場合には、前記接触酸化槽の流出水を汚泥濃縮設備に供給して濃縮することを特徴とする廃水の接触酸化法。

In the contact oxidation method of waste water, which is obtained by subjecting waste water to contact oxidation in a contact oxidation tank filled with a contact material, solid-liquid separation in a sedimentation tank to obtain treated water, floating of the outflow water from the contact oxidation tank The coefficients k, a, b, and c of the following equation (1), which is a relational expression between the concentration of substances and the water area load of the settling tank, are obtained through preliminary tests, and the measured values of the effluent water temperature, SVI, and water area load are calculated. Comparing the calculated value of the suspended water suspended matter concentration obtained by substituting into the formula 1 with the measured value of the suspended water suspended matter concentration, and if the measured value is less than or equal to the calculated value, The effluent from the contact oxidation tank is supplied to a precipitation tank for solid-liquid separation, and if the measured value exceeds the calculated value, the effluent from the contact oxidation tank is supplied to a sludge concentrating facility for concentration. A catalytic oxidation method for wastewater.

廃水を接触材が充填された接触酸化槽で接触酸化処理した後の流出水を、沈澱槽で固液分離して処理水とする廃水の接触酸化法において、前記接触酸化槽の流出水の浮遊物濃度と沈澱槽の水面積負荷との関係式である下記の１式の係数ｋ，ａ，ｂ，ｃを予備試験により求めると共に、流出水の水温、ＳＶＩ、および浮遊物濃度の測定値を、１式に代入することにより得られた流出水の水面積負荷の計算値と、前記流出水の水面積負荷の測定値とを比較し、前記測定値が前記計算値以下の場合には、前記接触酸化槽の流出水を沈澱槽に供給して固液分離し、前記測定値が前記計算値を越える場合には、前記接触酸化槽の流出水を汚泥濃縮設備に供給して濃縮することを特徴とする廃水の接触酸化法。

In the contact oxidation method of waste water, which is obtained by subjecting waste water to contact oxidation in a contact oxidation tank filled with a contact material, solid-liquid separation in a sedimentation tank to obtain treated water, floating of the outflow water from the contact oxidation tank The coefficients k, a, b, and c of the following equation (1), which is a relational expression between the concentration of matter and the water load on the settling tank, are obtained through preliminary tests, and the measured values of the effluent water temperature, SVI, and suspended matter concentration are obtained. Compare the calculated value of the water area load of the effluent water obtained by substituting into the formula, and the measured value of the water area load of the effluent water, if the measured value is less than or equal to the calculated value, Supply the effluent from the contact oxidation tank to a sedimentation tank for solid-liquid separation, and if the measured value exceeds the calculated value, supply the effluent from the contact oxidation tank to a sludge concentrating facility for concentration. A catalytic oxidation method for wastewater.

請求項１または２記載の廃水の接触酸化法において、異なる浮遊物濃度の流出水に凝集剤を添加して固液分離する際に、処理水の浮遊物濃度を目標値以下に維持し得る凝集剤添加量と流出水の浮遊物濃度との検量線を予備試験により求め、この検量線を利用して流出水の浮遊物濃度に応じて凝集剤を添加した後、沈澱槽で固液分離することを特徴とする廃水の接触酸化法。In the method of catalytic oxidation of wastewater according to claim 1 or 2, when the flocculant is added to the effluent of different suspended matter concentration and solid-liquid separation is performed, the suspended matter concentration of the treated water can be maintained below the target value. A calibration curve between the amount of added agent and the suspended solids concentration is obtained by a preliminary test. Using this calibration curve, a flocculant is added according to the suspended matter concentration in the effluent, and then solid-liquid separation is performed in the sedimentation tank. A catalytic oxidation method for wastewater.

廃水を接触材が充填された接触酸化槽で接触酸化処理した後の流出水を、沈澱槽で固液分離して処理水とする廃水の接触酸化法において、前記接触酸化槽の剥離汚泥の浮遊物濃度と沈澱槽の水面積負荷との関係式である下記の１式の係数ｋ，ａ，ｂ，ｃを予備試験により求めると共に、剥離汚泥の水温、ＳＶＩ、および水面積負荷の測定値を、１式に代入することにより得られた剥離汚泥の浮遊物濃度の計算値と、前記剥離汚泥の浮遊物濃度の測定値とを比較し、前記測定値が前記計算値以下の場合には、前記接触酸化槽の剥離汚泥を沈澱槽に供給して固液分離し、前記測定値が、前記計算値を越える場合には、前記接触酸化槽の剥離汚泥を汚泥濃縮設備に供給して濃縮することを特徴とする廃水の接触酸化法。

In the waste water contact oxidation method in which waste water is subjected to contact oxidation treatment in a contact oxidation tank filled with a contact material and solid-liquid separated in a sedimentation tank to obtain treated water, floating sludge is separated from the contact oxidation tank. The coefficient k, a, b, c of the following equation 1 which is a relational expression between the concentration of substances and the water area load of the settling tank is obtained by a preliminary test, and measured values of the water temperature, SVI, and water area load of the exfoliated sludge are obtained. Compare the calculated value of the floating sludge concentration of the exfoliated sludge obtained by substituting into the formula 1, and the measured value of the floating sludge concentration of the exfoliated sludge, and if the measured value is less than the calculated value, The separation sludge from the contact oxidation tank is supplied to a sedimentation tank for solid-liquid separation, and if the measured value exceeds the calculated value, the separation sludge from the contact oxidation tank is supplied to a sludge concentration facility and concentrated. A catalytic oxidation method for wastewater.

廃水を接触材が充填された接触酸化槽で接触酸化処理した後の流出水を、沈澱槽で固液分離して処理水とする廃水の接触酸化法において、前記接触酸化槽の剥離汚泥の浮遊物濃度と沈澱槽の水面積負荷との関係式である下記の１式の係数ｋ，ａ，ｂ，ｃを予備試験により求めると共に、剥離汚泥の水温、ＳＶＩ、および浮遊物濃度の測定値を、１式に代入することにより得られた剥離汚泥の水面積負荷の計算値と、前記剥離汚泥の水面積負荷の測定値とを比較し、前記測定値が前記計算値以下の場合には、前記接触酸化槽の剥離汚泥を沈澱槽に供給して固液分離し、前記測定値が前記計算値を越える場合には、前記接触酸化槽の剥離汚泥を汚泥濃縮設備に供給して濃縮することを特徴とする廃水の接触酸化法。

In the waste water contact oxidation method in which waste water is subjected to contact oxidation treatment in a contact oxidation tank filled with a contact material and solid-liquid separated in a sedimentation tank to obtain treated water, floating sludge is separated from the contact oxidation tank. The coefficient k, a, b, c of the following equation (1), which is a relational expression between the concentration of substances and the water load on the settling tank, is obtained by a preliminary test, and measured values of exfoliated sludge water temperature, SVI, and suspended solids concentration are obtained. Compare the calculated value of the water area load of the exfoliated sludge obtained by substituting into the formula, and the measured value of the water area load of the exfoliated sludge, and if the measured value is below the calculated value, The separation sludge from the contact oxidation tank is supplied to a sedimentation tank for solid-liquid separation. If the measured value exceeds the calculated value, the separation sludge from the contact oxidation tank is supplied to a sludge concentration facility and concentrated. A catalytic oxidation method for wastewater.

請求項４または５記載の廃水の接触酸化法において、異なる浮遊物濃度の剥離汚泥に凝集剤を添加して固液分離する際に、処理水の浮遊物濃度を目標値以下に維持し得る凝集剤添加量と剥離汚泥の浮遊物濃度との検量線を予備試験により求め、この検量線を利用して剥離汚泥の浮遊物濃度に応じて凝集剤を添加した後、沈澱槽で固液分離することを特徴とする廃水の接触酸化法。6. The contact oxidation method of waste water according to claim 4 or 5, wherein the flocculent concentration of the treated water can be maintained below the target value when the flocculant is added to the exfoliated sludge having a different float concentration to perform solid-liquid separation. A calibration curve between the amount of added agent and the suspended sludge concentration in the sludge is obtained by a preliminary test. Using this calibration curve, a flocculant is added according to the suspended sludge concentration in the separated sludge, and then solid-liquid separation is performed in the precipitation tank. A catalytic oxidation method for wastewater.

沈澱槽で固液分離された汚泥の一部を、返送汚泥として接触酸化槽に返送することを特徴とする請求項１〜６のいずれかに記載の廃水の接触酸化法。The wastewater contact oxidation method according to any one of claims 1 to 6, wherein a part of the sludge separated into solid and liquid in the settling tank is returned to the contact oxidation tank as return sludge.