JPH11169887A - Flocculant injection control method in water treatment process and device therefor - Google Patents

Flocculant injection control method in water treatment process and device therefor

Info

Publication number
JPH11169887A
JPH11169887A JP34104497A JP34104497A JPH11169887A JP H11169887 A JPH11169887 A JP H11169887A JP 34104497 A JP34104497 A JP 34104497A JP 34104497 A JP34104497 A JP 34104497A JP H11169887 A JPH11169887 A JP H11169887A
Authority
JP
Japan
Prior art keywords
phosphorus
water
coagulant
tank
flocculant
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP34104497A
Other languages
Japanese (ja)
Inventor
Naoki Hara
直樹 原
Fumitomo Kimura
文智 木村
Shoji Watanabe
昭二 渡辺
Toshiro Hayasaka
敏郎 早坂
Akio Kimura
章夫 木村
Yoshiaki Tashiro
義昭 田代
Yoshiyuki Osawa
義行 大沢
Saburo Ando
三郎 安藤
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi Ltd filed Critical Hitachi Ltd
Priority to JP34104497A priority Critical patent/JPH11169887A/en
Publication of JPH11169887A publication Critical patent/JPH11169887A/en
Pending legal-status Critical Current

Links

Abstract

PROBLEM TO BE SOLVED: To provide an injection control system of flocculant properly complementing phosphorus removing ability in a sewerage activated sludge process without depending on the continuous measurment of dissolved phosphorus. SOLUTION: A flocculant injection device 150 for removing phoshorus is installed near the outlet of a biological reaction vessel composed of an anaerobic vessel 20 and an aerobic vessel 21. The dissolved oxygen concentration (DO) 200 is measured by a DO meter provided at the flowing-in sewerage inlet of the anaerobic vessel 20 and transmitted to a flocculant injection control device 300. A phosphorus removal judging part 301 calculates the phosphorus removing ratio after the retention time based on a fixed relation (inverse proportion) between the flowing-in water DO and the phosphorus removing ratio in the biological reaction layer and judges that the removal of phosphorus is bad in the case that the resultant value is <= the threshold 302 of judgement. Receiving the judgement that the removal of phosphorus is poor, the flocculant injection control part 310 decides the injecting quantity based on the standard flocculant quantity 311 per unit treating water flow rate and a treating water (Qi+Qr) and the flocculant is injected after the retention time in the biological reaction vessel by controlling the flocculant injection device 150.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【0001】[0001]

【発明の属する技術分野】本発明は、都市下水や産業排
水あるいは水道原水を生物学的に処理するシステムに係
わり、特に、流入水中のリンを安定に除去するリン除去
方法及び装置に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for biologically treating municipal sewage, industrial effluent or tap water, and more particularly to a method and an apparatus for stably removing phosphorus in influent water.

【0002】[0002]

【従来の技術】近年、湖沼や湾などへ流入する下水の窒
素やリンによって、これら閉鎖性水域での富栄養化が進
行している。下水処理場では、生活排水や工場排水など
の流入下水に対して、活性汚泥法と呼ばれる微生物処理
で主に下水中の有機物を除去している。下水中にはこの
他にも、主にオルトリン酸(PO4‐P)やアンモニア
性窒素として流入する窒素やリンが含まれ、これらが下
水処理場で除去できずに放流されると、これを栄養源と
する藻類が異常繁殖して水質汚濁の原因となる。したが
って、有機物に加えてリンや窒素も除去可能な方式を導
入する下水処理場が増加している。
2. Description of the Related Art In recent years, eutrophication in closed water bodies has been progressing due to nitrogen and phosphorus in sewage flowing into lakes and marshes. In sewage treatment plants, organic matter in sewage is mainly removed from incoming sewage such as domestic wastewater and industrial wastewater by a microbial treatment called an activated sludge method. In addition to this, sewage mainly contains orthophosphoric acid (PO 4 -P) and nitrogen and phosphorus which flow in as ammoniacal nitrogen. If these are discharged without being removed at the sewage treatment plant, they are discharged. Algae as a nutrient source grow abnormally and cause water pollution. Therefore, the number of sewage treatment plants that introduce a method capable of removing phosphorus and nitrogen in addition to organic matter is increasing.

【0003】リン除去の物理化学的な方法として凝集法
がある。凝集法は原水または沈殿水に凝集剤を添加して
リンを凝集沈殿させる方式で、効率のよいリン除去が可
能である。しかし、従来の活性汚泥設備とは別に凝集沈
殿設備を新たに導入しなければならず、建設コストや敷
地の確保、凝集剤の連続注入によるランニングコストな
ど、実運用には問題が多い。
A coagulation method is a physicochemical method for removing phosphorus. The coagulation method is a method in which a coagulant is added to raw water or settling water to coagulate and precipitate phosphorus, and efficient phosphorus removal is possible. However, a coagulation sedimentation facility must be newly introduced in addition to the conventional activated sludge facility, and there are many problems in actual operation, such as construction costs, securing a site, and running costs due to continuous injection of a coagulant.

【0004】一方、凝集剤を用いないリン除去方法とし
て、活性汚泥プロセスの一施設である嫌気槽を好気領域
と嫌気領域に改造し、これらの領域を有効に組み合わせ
た微生物反応槽の作用によってリンを除去する生物学的
リン除去法がある。これによれば、酸素のない嫌気状態
では活性汚泥が菌体内に蓄積しているポリリン酸をオル
トリン酸として放出し、好気状態では活性汚泥が前段で
放出した以上のオルトリン酸を摂取し菌体内にポリリン
酸として蓄積する。このため、リンは流入水よりも好気
槽出口で減少する。
On the other hand, as a method for removing phosphorus without using a flocculant, an anaerobic tank, which is a facility of the activated sludge process, is remodeled into an aerobic area and an anaerobic area, and the action of a microbial reactor effectively combining these areas is performed. There are biological phosphorus removal methods that remove phosphorus. According to this, in an anaerobic state without oxygen, activated sludge releases polyphosphoric acid accumulated in the cells as orthophosphoric acid, and in an aerobic state, the activated sludge ingests more orthophosphoric acid than released in the previous stage, and the cells in the bacterium are ingested. Accumulates as polyphosphoric acid. For this reason, phosphorus is reduced at the aerobic tank outlet rather than at the influent.

【0005】この生物学的リン除去法には嫌気‐好気法
(AO法)、嫌気‐無酸素‐好気法(A2O法)などが
あるが、嫌気状態でリンを放出する反応と、好気状態で
リンを摂取する反応との2工程を経由しなければならな
い。したがって、嫌気槽でオルトリン酸を良好に活性汚
泥から放出させ、好気槽でオルトリン酸を効率よく摂取
させる必要がある。
[0005] The biological phosphorus removal method includes an anaerobic-aerobic method (AO method) and an anaerobic-anoxic-aerobic method (A2O method). It must go through two steps: the reaction of taking phosphorus in the air. Therefore, it is necessary to properly release orthophosphoric acid from activated sludge in an anaerobic tank and to efficiently ingest orthophosphoric acid in an aerobic tank.

【0006】しかし、生物学的リン除去法は凝集沈殿法
に比べると、リン除去能力が変動して回復には時間がか
かるため安定性に欠ける。このため、好気槽出口に凝集
剤注入設備を付加し、生物学的リン除去能力が低下した
場合は、凝集剤を注入してリンを除去している。このよ
うな生物学的方法と物理化学的方法を併用したリン除去
方法として、流入水中のリン濃度に基づいて凝集剤量を
決定する方法(引用例1:特開昭63-242392号)、放流
水中のリン濃度に基づいて凝集剤量を制御する方法(引
用例2:特開平3-89993号)、微生物反応槽の酸化還元
電位(ORP)に基づいて凝集剤を添加する方法(引用
例3:特開平3-278896号)などが提案されている。
[0006] However, the biological phosphorus removal method is less stable than the coagulation sedimentation method because the phosphorus removal ability fluctuates and recovery takes time. For this reason, a coagulant injection facility is added to the outlet of the aerobic tank, and when the ability to remove biological phosphorus decreases, a coagulant is injected to remove phosphorus. As a method of removing phosphorus by using such a biological method and a physicochemical method together, a method of determining the amount of a flocculant based on the concentration of phosphorus in the influent water (Citation 1: JP-A-63-242392), A method of controlling the amount of coagulant based on the concentration of phosphorus in water (Cited Example 2: JP-A-3-89993), a method of adding a coagulant based on the oxidation-reduction potential (ORP) of a microbial reaction tank (Cited Example 3) : JP-A-3-278896).

【0007】[0007]

【発明が解決しようとする課題】引用例1,2に提案さ
れている流入水または方流水のリン濃度を計測して、凝
集剤の添加量を制御する方式は、流入水、放流水のリン
を連続計測してモニタリングする装置が高価(約800
万円/台)で、かつ連続使用期間に匹敵するようなメン
テナンス期間を必要とするため、実用化されていないの
が現状である。
The method proposed in References 1 and 2 for controlling the amount of coagulant added by measuring the phosphorus concentration of inflow water or sidestream water is based on the method of controlling the phosphorus content of inflow water and discharge water. Is expensive (approximately 800
It has not been put into practical use because it requires a maintenance period equivalent to a continuous use period.

【0008】また、生物状態が正常であれば流入水のリ
ン濃度が高くてもある程度までは除去が可能であるが、
生物状態が不正常であれば通常、処理可能なリン濃度で
も除去できなくなる。このように、微生物の状態によっ
てリン除去能力が変動するので、流入水のリン濃度から
生物処理後の放流水のリン濃度を予測し、凝集剤の要否
の判断や添加量を決定することは難しい。
In addition, if the biological condition is normal, it can be removed to some extent even if the concentration of phosphorus in the inflow water is high.
If the biological state is unusual, it will usually not be possible to remove even the processable phosphorus concentration. As described above, since the phosphorus removal ability varies depending on the state of microorganisms, it is not possible to predict the phosphorus concentration of the discharge water after biological treatment from the phosphorus concentration of the influent water, to determine the necessity of the flocculant, and to determine the amount of addition. difficult.

【0009】また、放流水リンを一定値以下に保つよう
に制御した場合、放流水リンが基準値を超えて凝集剤注
入を開始するまでに沈殿池滞留時間(2〜3時間)に相
当する遅れが生じる。凝集剤注入停止についても同様
で、嫌気槽と好気槽の滞留時間による数時間の遅れが出
る。滞留時間の長い生物反応槽では、放流水のリン濃度
で凝集剤をフィードバック制御しても適正な注入は困難
になる。また、凝集剤注入時、その一部はプロセスを循
環しているため、放流水のリン濃度から生物学的なリン
除去能力の回復を把握することが難しい。従って、凝集
剤注入停止のタイミングを的確に把握することも困難に
なる。
When the discharge water phosphorus is controlled to be kept below a certain value, it corresponds to the sedimentation tank residence time (2 to 3 hours) until the discharge water phosphorus exceeds the reference value and the coagulant is injected. There is a delay. The same applies to the stoppage of coagulant injection, with a delay of several hours due to the residence time of the anaerobic tank and the aerobic tank. In a biological reaction tank having a long residence time, even if the flocculant is feedback-controlled by the phosphorus concentration of the discharge water, it becomes difficult to properly inject the coagulant. In addition, when the coagulant is injected, part of the coagulant is circulating in the process, so it is difficult to grasp the recovery of the biological phosphorus removal ability from the phosphorus concentration of the effluent. Therefore, it is also difficult to accurately grasp the timing of stopping the coagulant injection.

【0010】引用例3に提案されている嫌気槽のORP
に基づく方式は原理的に問題がある。本発明者等の実験
的検証によれば、好気槽での酸化反応の程度を示す好気
度の理論値とORPの計測値(正の電位)とは良い相関
が認められた。しかし、嫌気槽のORPの計測値(負の
電位)は近接配置した複数の電極間においても一定せ
ず、還元反応を示す嫌気度の定量的把握が困難であっ
た。このように、嫌気状態でのORPの計測値は不定で
あり、これを基に放流水のリン濃度を予測して凝集剤の
添加制御を行なうことは不可能と思われる。
ORP of anaerobic tank proposed in Reference 3
There is a problem in principle with the method based on. According to the experimental verification by the present inventors, a good correlation was observed between the theoretical value of aerobicity indicating the degree of the oxidation reaction in the aerobic tank and the measured value of ORP (positive potential). However, the measured value (negative potential) of the ORP in the anaerobic tank was not constant even between a plurality of electrodes arranged in close proximity, and it was difficult to quantitatively grasp the anaerobic degree indicating the reduction reaction. As described above, the measured value of the ORP in the anaerobic state is indefinite, and it is considered impossible to predict the phosphorus concentration of the effluent and control the addition of the flocculant based on the measured value.

【0011】凝集剤はコスト高の上、活性汚泥の生物に
影響を与え正常な生物状態を悪化させる可能性があるの
で、凝集剤の添加は生物によるリン除去能力の低下時の
み補完的に、最小限に行なわれるのが望ましい。しか
し、リン除去能力を把握して凝集剤を適正に注入する方
法は実現されていなかった。
[0011] Since the flocculant has a high cost and may affect the activated sludge organisms to deteriorate the normal biological condition, the addition of the flocculant complements only when the ability of the organisms to remove phosphorus decreases. It is desirable that this be done to a minimum. However, a method of grasping the phosphorus removal ability and injecting the coagulant properly has not been realized.

【0012】本発明の目的は、上記した従来技術の状況
に鑑み、リン濃度の連続計測を使用することなく、生物
学的リン除去能力をリアルタイムに予測して、その低下
時のみ補完的に、さらには最小限に凝集剤を注入できる
水処理プロセスのリン除去方法および装置を提供するこ
とにある。
SUMMARY OF THE INVENTION In view of the state of the prior art described above, an object of the present invention is to predict biological phosphorus removal ability in real time without using continuous measurement of phosphorus concentration, and complementarily only when the ability is reduced, Another object of the present invention is to provide a method and an apparatus for removing phosphorus in a water treatment process, which can inject a flocculant to a minimum.

【0013】[0013]

【課題を解決するための手段】本発明者らは、流入水中
の溶存酸素濃度(DO)と生物反応槽のリン除去能力を
示すリン除去率の間に、密接な関係があることを実験的
に見いだし、以下の本発明に至った。
The present inventors have experimentally determined that there is a close relationship between the dissolved oxygen concentration (DO) in the influent water and the phosphorus removal rate, which is indicative of the phosphorus removal capacity of the biological reactor. Have led to the present invention described below.

【0014】上記目的を達成する本発明は、微生物を嫌
気状態、次いで好気状態とする生物反応槽の水処理プロ
セスで、流入水中の溶解性リンを過剰摂取して放流水の
リンを除去する方法において、流入水中の溶存酸素濃度
(DO)と生物学的リン除去能力を示すリン除去率の所
定関係に基づいて、サンプリングタイミング毎に計測し
た流入水のDOからリン除去率を求め、この除去率が一
定値以下となる場合にこの除去率が一定値以下となる場
合に凝集剤を注入する間欠制御を行なうことを特徴とす
る。
[0014] The present invention to achieve the above object is to remove phosphorus in effluent water by excessively taking in soluble phosphorus in influent water in a water treatment process of a biological reaction tank in which microorganisms are placed in an anaerobic state and then in an aerobic state. In the method, based on a predetermined relationship between a dissolved oxygen concentration (DO) in an inflow water and a phosphorus removal rate indicating a biological phosphorus removal ability, a phosphorus removal rate is obtained from the inflow water DO measured at each sampling timing, and the removal is determined. When the rate is equal to or less than a certain value, the intermittent control for injecting the coagulant is performed when the removal rate is equal to or less than a certain value.

【0015】前記流入水のDOとリン除去率の所定関係
はほぼ逆比例となる。また、前記凝集剤の所定量は、当
該処理プロセスにおける放流水のリン濃度の実績値に基
づいて決定され、リン濃度を目標値以下に維持できる基
準凝集剤量と、前記生物反応槽の処理水量の計測値から
求める。なお、凝集剤の注入必要時に放流水のリン濃度
を測定し、目標値との差分から注入量を決定することも
できる。
The predetermined relationship between the inflow water DO and the phosphorus removal rate is substantially inversely proportional. Further, the predetermined amount of the coagulant is determined based on the actual value of the phosphorus concentration of the effluent in the treatment process, a reference coagulant amount capable of maintaining the phosphorus concentration at or below the target value, and a treated water amount of the biological reaction tank. From the measured value of When the coagulant needs to be injected, the phosphorus concentration of the discharged water can be measured, and the injection amount can be determined from the difference from the target value.

【0016】また、前記凝集剤の注入は当該DOの測定
から所定時間後に実行され、この所定時間は前記生物反
応槽の滞留時間を目安として予め設定されることを特徴
とする。
Further, the injection of the flocculant is performed after a predetermined time from the measurement of the DO, and the predetermined time is set in advance based on a residence time of the biological reaction tank.

【0017】さらに、上記目的を達成する本発明は、上
流側から嫌気槽と好気槽を有する生物反応槽と、その下
流の沈殿池と、前記好気槽にリン除去用の凝集剤注入装
置とを備える水処理システムにおいて、流入水の溶存酸
素(DO)計測手段と、該計測手段で計測したDOから
前記生物反応槽のリン除去能力の良否を判定するリン除
去判定手段と、該判定手段で能力不良と判定された場合
に前記凝集剤注入装置に凝集剤の注入指示を与える凝集
剤注入制御手段を設けたことを特徴とする。
Further, the present invention, which achieves the above object, comprises a biological reaction tank having an anaerobic tank and an aerobic tank from the upstream side, a sedimentation tank downstream thereof, and a coagulant injection device for removing phosphorus into the aerobic tank. A water treatment system comprising: a dissolved oxygen (DO) measuring means for influent water; a phosphorus removing judging means for judging the quality of the phosphorus removing ability of the biological reaction tank from DO measured by the measuring means; Wherein the coagulant injection device is provided with a coagulant injection control means for instructing the coagulant injection device to instruct an injection of the coagulant when it is determined that the coagulant is defective.

【0018】本発明の作用を説明する。嫌気槽における
リン放出を阻害する要因として、流入下水中の溶存酸素
や硝酸性窒素の上昇、有機物の低下がある。特に、降雨
時には流入下水の溶存酸素の上昇と同時に有機物も低下
するので、嫌気槽のリン放出が発生せず、好気槽におけ
るリンの過剰摂取も発生しない。
The operation of the present invention will be described. Factors inhibiting phosphorus release in the anaerobic tank include an increase in dissolved oxygen and nitrate nitrogen in the inflow sewage and a decrease in organic matter. In particular, at the time of rainfall, the dissolved matter in the incoming sewage rises, and at the same time, the amount of organic matter also decreases, so that phosphorus is not released from the anaerobic tank, and excessive intake of phosphorus in the aerobic tank does not occur.

【0019】図2に、実験データによる流入水DOと嫌
気槽のリン放出量の関係を示す。嫌気槽のリン放出量
は、流入水DOと共に測定した嫌気槽の入口リン濃度P
inと、出口リン濃度Poutから求めたリン濃度の増加分
である。リン放出量はDOの増加と共に急激に低下し、
リン放出量が小さくなると好気槽20での過剰摂取も進
行せず、リン除去率が低下する。
FIG. 2 shows the relationship between the inflow water DO and the amount of phosphorus released from the anaerobic tank based on experimental data. The amount of phosphorus released from the anaerobic tank is determined by the phosphorus concentration P at the inlet of the anaerobic tank measured together with the inflow water DO.
In and the increase in the phosphorus concentration obtained from the outlet phosphorus concentration Pout. Phosphorous release decreases rapidly with increasing DO,
When the amount of released phosphorus becomes small, excessive intake in the aerobic tank 20 does not progress, and the phosphorus removal rate decreases.

【0020】図3に、流入下水DOとリン除去率の関係
を示す。リン除去率は数1で求められる。
FIG. 3 shows the relationship between the inflow sewage DO and the phosphorus removal rate. The phosphorus removal rate is obtained by Equation 1.

【0021】[0021]

【数1】リン除去率=(流入水リン濃度−放流水リン濃
度)/流入水リン濃度 ここで、流入水リン濃度は流入水DOと同時刻の計測
値、放流水リン濃度はその流入水が生物反応槽を伝搬し
て好気槽出口に達する時刻(生物反応槽の滞留時間)の
計測値である。図示のように、リン除去率は流入下水D
Oの増加と共にほぼ直線的に低下している。
## EQU1 ## Phosphorus removal rate = (influent phosphorus concentration-effluent phosphorus concentration) / influent phosphorus concentration Here, the influent phosphorus concentration is a measured value at the same time as the influent DO, and the effluent phosphorus concentration is the influent water. Is the measured value of the time (residence time of the biological reaction tank) at which the sample propagates through the biological reaction tank and reaches the aerobic tank outlet. As shown in the figure, the phosphorus removal rate is
It decreases almost linearly with the increase of O.

【0022】図4に、リン除去率と嫌気槽のリン放出量
の関係を示す。図4の関係は、図2と図3から得られ
る。リン放出量が高いときにはリン除去率が高く約90
%に安定している。しかし、リン放出量が小さくなるに
従ってリン除去率は直線的に低下する。
FIG. 4 shows the relationship between the phosphorus removal rate and the amount of phosphorus released from the anaerobic tank. The relationship of FIG. 4 can be obtained from FIGS. 2 and 3. When the phosphorus release is high, the phosphorus removal rate is high and about 90%.
% Stable. However, as the amount of released phosphorus decreases, the phosphorus removal rate decreases linearly.

【0023】以上の実験結果から、生物反応槽のリン除
去能力は嫌気槽のリン放出量に依存し、リン放出量は流
入水DOに依存し、そして、リン除去能力を示すリン除
去率は流入水DOとほぼ逆比例の関係にあることが認め
られる。これより、所定のリン除去率、例えば80%を
しきい値として、それ以下となるときは生物反応槽のリ
ン除去能力を不良と判定し、凝集剤の注入を決定する。
From the above experimental results, the phosphorus removal capacity of the biological reaction tank depends on the amount of phosphorus released from the anaerobic tank, the phosphorus release quantity depends on the influent DO, and the phosphorus removal rate indicating the phosphorus removal capacity is the inflow rate. It is recognized that there is a substantially inverse relationship with water DO. From this, a predetermined phosphorus removal rate, for example, 80% is set as a threshold value, and when it is lower than the threshold value, the phosphorus removal ability of the biological reaction tank is determined to be poor, and injection of the flocculant is determined.

【0024】このように、嫌気槽でのリン放出が不十分
な場合に、好気槽出口で凝集剤を注入してリン除去作用
を補完することで、放流水のリンを安定して除去でき
る。本発明によれば、生物学的リン除去能力の低下した
ときにのみ、凝集剤を間欠注入するので、ランニングコ
ストが低く活性汚泥に対する悪影響も少ない。
As described above, when the release of phosphorus from the anaerobic tank is insufficient, the coagulant is injected at the outlet of the aerobic tank to supplement the phosphorus removing action, whereby the phosphorus in the discharged water can be removed stably. . According to the present invention, since the coagulant is intermittently injected only when the biological phosphorus removal ability is reduced, the running cost is low and the adverse effect on the activated sludge is small.

【0025】また、流入水の計測DOに基づくリン除去
率は、その流入水が生物反応槽を伝搬して出口から放流
される時の予測値である。従って、制御の遅れが無く、
凝集剤注入停止のタイミングも的確に把握できる。か
つ、処理水のリン濃度を連続計測してモニタリングする
装置が不要で、既存の下水道設備等への適用が容易にな
る。
The phosphorus removal rate based on the measured DO of the inflow water is a predicted value when the inflow water propagates through the biological reaction tank and is discharged from the outlet. Therefore, there is no control delay,
The timing of stopping the coagulant injection can also be accurately grasped. In addition, there is no need for a device for continuously measuring and monitoring the phosphorus concentration of the treated water, and application to existing sewerage facilities and the like is facilitated.

【0026】[0026]

【発明の実施の形態】以下、本発明の一実施例を図面を
参照しながら詳細に説明する。図1は、生物反応槽を持
つ下水処理設備に、本発明のリン除去方式を適用したシ
ステムの構成図である。下水処理設備は最初沈殿池1
5、嫌気槽20、好気槽21、最終沈殿池30、送風用
ブロワ110などから構成されている。
An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a configuration diagram of a system in which the phosphorus removal method of the present invention is applied to a sewage treatment facility having a biological reaction tank. First sewage treatment facility settling basin 1
5, the anaerobic tank 20, the aerobic tank 21, the final sedimentation basin 30, the blower 110 for blowing, and the like.

【0027】家庭や工場から排出された流入下水10は
最初沈殿池15で粗大なゴミ、砂などを除去され、嫌気
槽21に導かれる。嫌気槽20には活性汚泥と呼ばれる
微生物群が、最終沈殿池30から汚泥返送管70を介し
て返送汚泥として供給され、機械撹拌設備41でにより
流入下水と撹拌混合される。嫌気槽21には曝気用の空
気を送給せずに無酸素の嫌気状態とする。
The inflow sewage 10 discharged from homes and factories is first subjected to a sedimentation basin 15 to remove coarse dust, sand, etc., and then led to an anaerobic tank 21. Microorganisms called activated sludge are supplied to the anaerobic tank 20 as return sludge from the final sedimentation basin 30 via the sludge return pipe 70 and are stirred and mixed with the inflow sewage by the mechanical stirring equipment 41. The anaerobic tank 21 is brought into an oxygen-free anaerobic state without supplying air for aeration.

【0028】嫌気状態において、活性汚泥は体内に蓄積
していたポリリン酸を加水分解しオルトリン酸(PO4
‐P)として下水中に放出する。また、活性汚泥はオル
トリン酸放出と同時に有機物を吸着し菌体内に蓄積す
る。この生物反応によって、嫌気槽21ではリンが増加
し有機物が減少する。
In an anaerobic condition, activated sludge hydrolyzes polyphosphoric acid accumulated in the body to form orthophosphoric acid (PO 4
-P) into sewage. Activated sludge adsorbs organic substances and accumulates in the cells simultaneously with the release of orthophosphoric acid. Due to this biological reaction, phosphorus increases in the anaerobic tank 21 and organic matter decreases.

【0029】嫌気槽20からの流出水は好気槽21に導
かれる。好気槽21の底部には散気管40が設置され、
ブロワ110から空気管130を介して送給された空気
が散気し、好気槽21内の下水と活性汚泥からなる混合
液を撹拌するとともに酸素を供給する。
The effluent from the anaerobic tank 20 is led to the aerobic tank 21. A diffuser 40 is provided at the bottom of the aerobic tank 21,
The air sent from the blower 110 via the air pipe 130 diffuses, agitates the mixture of sewage and activated sludge in the aerobic tank 21 and supplies oxygen.

【0030】活性汚泥は微生物の凝集した粒径0.1〜1.0
mm前後の塊(フロック)で、数十種の微生物を含む。
好気槽21内の混合液の汚濁物質は、酸素供給により活
発化した活性汚泥の働きによって処理される。例えば、
活性汚泥は有機物を吸着し、供給された空気中の酸素を
吸収して有機物を酸化分解して炭酸ガスと水にする。ま
た、活性汚泥は下水中のオルトリン酸を摂取し、ポリリ
ン酸として菌体内に蓄積する。また、アンモニア性窒素
(NH4‐N)は硝酸性(NO3‐N)あるいは亜硝酸性
窒素(NO2‐N)に酸化される。これら有機物、リ
ン、アンモニア性窒素などの汚濁物質の一部は、活性汚
泥の増殖にも利用される。
The activated sludge has an aggregated particle size of microorganisms of 0.1 to 1.0.
It is a block (flock) of about mm and contains several tens of microorganisms.
The pollutants of the mixed liquid in the aerobic tank 21 are treated by activated sludge activated by the supply of oxygen. For example,
Activated sludge adsorbs organic matter, absorbs oxygen in the supplied air, and oxidizes and decomposes the organic matter to carbon dioxide and water. Activated sludge also ingests orthophosphoric acid in sewage and accumulates in cells as polyphosphoric acid. In addition, ammonia nitrogen (NH 4 -N) is oxidized to nitrate (NO 3 -N) or nitrite nitrogen (NO 2 -N). Some of these pollutants, such as organic matter, phosphorus and ammoniacal nitrogen, are also used for growing activated sludge.

【0031】活性汚泥と下水の混合液は最終沈殿池30
に導かれ、活性汚泥が重力沈降する。最終沈殿池30の
上澄液は通常、塩素殺菌処理した後に、河川や海に放流
される。一方、沈殿した高濃度の活性汚泥は、その大部
分が汚泥返送設備60により、返送汚泥として嫌気槽2
0に返送され、微生物増殖分に相当する一部の活性汚泥
が余剰汚泥として汚泥排出設備90で系外に排出され、
脱水や焼却等の汚泥処理工程を経て処理される。
The mixed liquid of the activated sludge and the sewage is supplied to the final sedimentation basin 30.
Activated sludge is settled by gravity. The supernatant of the final sedimentation basin 30 is usually discharged into a river or sea after chlorine sterilization. On the other hand, most of the precipitated high-concentration activated sludge is returned to the anaerobic tank 2 by the sludge return equipment 60 as returned sludge.
0, and part of the activated sludge corresponding to the microbial growth is discharged out of the system as excess sludge by the sludge discharge equipment 90,
Processed through a sludge treatment process such as dehydration and incineration.

【0032】この活性汚泥プロセスにおいて、最終沈殿
池30からの放流水は、放流水域の溶存酸素を消費する
ことがなく、また汚染を進行させない水質を目標として
いる。この水質確保のためには有機汚濁物質を除去し、
栄養塩類であるリンを除去することが重要である。
In the activated sludge process, the effluent from the final sedimentation basin 30 aims at a water quality that does not consume dissolved oxygen in the effluent area and does not cause pollution. To ensure this water quality, remove organic pollutants,
It is important to remove phosphorus, which is a nutrient.

【0033】嫌気槽20において、活性汚泥は嫌気状態
でオルトリン酸を放出するため、その入口よりも出口の
リン濃度が高くなる。しかし、好気槽21の好気状態下
で、活性汚泥は嫌気槽20によるリン放出量以上のオル
トリン酸を菌体内に摂取するので、その出口のオルトリ
ン酸が流入下水中より少なくなり、結果的に放流水のリ
ンが減少する。
In the anaerobic tank 20, the activated sludge releases orthophosphoric acid in an anaerobic state, so that the phosphorus concentration at the outlet is higher than that at the inlet. However, under the aerobic condition of the aerobic tank 21, the activated sludge ingests orthophosphoric acid into the cells more than the amount of phosphorus released by the anaerobic tank 20. The phosphorus in the effluent decreases.

【0034】このような活性汚泥のリンの放出と過剰摂
取による生物学的リン除去法は、嫌気槽20の嫌気状態
を維持してリン放出が正常になされていることを前提と
したプロセスであり、リン放出が不十分であるとリン過
剰摂取は進行せず、極端な場合には流入水より放流水の
リンが増加することもある。
[0034] The biological phosphorus removal method by releasing phosphorus and ingesting excessively the activated sludge is a process on the premise that the anaerobic condition of the anaerobic tank 20 is maintained and phosphorus is released normally. However, if the phosphorus release is insufficient, the excessive intake of phosphorus does not progress, and in extreme cases, the phosphorus in the discharged water may increase more than the inflow water.

【0035】本実施例では、このような生物学的リン除
去能力を補完するために、好気槽21の出口部に凝集剤
を注入する凝集剤注入ポンプ150、ポリ塩化アルミニ
ウム(PAC)などの金属塩凝集剤を貯える凝集剤タン
ク151、及び計算機で構成される凝集剤制御装置30
0を設け、DO計200による流入下水の計測値に基づ
いて凝集剤注入ポンプ150を制御する。生物反応槽で
除去できなかったリンは、凝集剤の金属陽イオンによっ
てオルトリン酸が不溶化されて、最終沈殿池30で沈降
除去される。
In this embodiment, in order to supplement such a biological phosphorus removing ability, a coagulant injection pump 150 for injecting the coagulant into the outlet of the aerobic tank 21 and a polyaluminum chloride (PAC) or the like are used. Coagulant tank 151 for storing metal salt coagulant, and coagulant control device 30 composed of a computer
0 is set, and the coagulant injection pump 150 is controlled based on the measured value of the inflow sewage measured by the DO meter 200. Phosphorus that could not be removed in the biological reaction tank is orthophosphoric acid insolubilized by the metal cation of the coagulant, and settled and removed in the final sedimentation basin 30.

【0036】DO計200は嫌気槽20の入口に設置
し、微生物反応前の流入水の溶存酸素(DO)を計測す
る。一般に、流入下水中のDOは0.1〜10.0 mg/l、嫌
気槽20では0.0〜1.0 mg/l、好気槽21では1.0 mg
/l以上を示す。
The DO meter 200 is installed at the entrance of the anaerobic tank 20, and measures the dissolved oxygen (DO) of the influent water before the microbial reaction. In general, DO in the incoming sewage is 0.1 to 10.0 mg / l, 0.0 to 1.0 mg / l in the anaerobic tank 20, and 1.0 mg in the aerobic tank 21.
Indicates / l or more.

【0037】凝集剤制御装置300は測定周期毎に、D
O計200から流入下水のDO計測値を入力し、リン除
去能力判定部301でDO値に対応するT1時間後のリ
ン除去率を演算して予測し、予め設定されている判定し
きい値302と比較する。なお、判定部301は流入水
のDOとリン除去率の線形関係を示す演算式またはデー
タテーブルを具備している。この結果、リン除去率がし
きい値以下であれば、生物反応槽のリン除去はT1時間
後には不良になると判定する。T1時間は、嫌気槽20
の入口に流入した下水が好気槽21の出口に達するまで
の滞留時間に相当する。
The coagulant control device 300 sets D
The DO measurement value of the inflow sewage is input from the O meter 200, and the phosphorus removal capability determination unit 301 calculates and predicts the phosphorus removal rate after T1 time corresponding to the DO value, and sets a predetermined determination threshold value 302. Compare with The determining unit 301 includes an arithmetic expression or a data table indicating a linear relationship between the DO of the inflow water and the phosphorus removal rate. As a result, if the phosphorus removal rate is equal to or less than the threshold value, it is determined that the phosphorus removal in the biological reaction tank becomes defective after the time T1. T1 time, anaerobic tank 20
Corresponds to a residence time until the sewage flowing into the inlet of the aerobic tank 21 reaches the outlet of the aerobic tank 21.

【0038】次に、凝集剤注入制御部310は、リン除
去能力判定部301からリン除去不良の判定結果を受け
取ると、予め設定されている処理水流量当たりの凝集剤
量311と、当該DOと同時測定した処理水流量、すな
わち流量計210による流入水量Qiと流量計220に
よる返送汚泥流量Qrの和とから、凝集剤の注入量を算
出する。そして、およそT1時間後に、算出した所定注
入量となるように凝集剤注入ポンプ150を制御する。
Next, the coagulant injection control section 310, upon receiving the determination result of the phosphorus removal failure from the phosphorus removal ability determination section 301, sets a predetermined amount of coagulant 311 per treated water flow rate, The coagulant injection amount is calculated from the simultaneously measured flow rate of the treated water, that is, the sum of the inflow water amount Qi by the flow meter 210 and the return sludge flow amount Qr by the flow meter 220. Then, approximately T1 hours later, the coagulant injection pump 150 is controlled so that the calculated predetermined injection amount is obtained.

【0039】凝集剤制御装置300は、複数台の凝集剤
注入ポンプ150の起動または停止を行なう台数制御に
よって所定注入量の凝集剤を注入する。あるいは、凝集
剤注入ポンプ150の回転数制御によって凝集剤注入量
を制御してもよい。
The coagulant control device 300 injects a predetermined amount of coagulant by controlling the number of coagulant injection pumps 150 to start or stop. Alternatively, the coagulant injection amount may be controlled by controlling the rotation speed of the coagulant injection pump 150.

【0040】また、凝集剤制御装置300は表示部32
0を有し、DOやリン除去率の数値を表示し、レベルに
よって表示色を変えたりアラームを出力してもよい。
The coagulant control device 300 is connected to the display unit 32
It may have a value of 0, display a numerical value of the DO or phosphorus removal rate, change the display color depending on the level, or output an alarm.

【0041】次に、本発明の他の実施例を説明する。図
5は、嫌気槽、無酸素槽、好気槽を用いたA2O法の下
水処理設備への一適用例を示す。図1と同等の要素には
同一の符号を付してある。
Next, another embodiment of the present invention will be described. FIG. 5 shows an example of application to an A2O sewage treatment facility using an anaerobic tank, an anoxic tank, and an aerobic tank. Elements equivalent to those in FIG. 1 are denoted by the same reference numerals.

【0042】本実施例は、好気槽21出口部の混合液を
循環ポンプ141で無酸素槽22に循環する。無酸素槽
22では嫌気槽20からの下水と返送汚泥の混合水、及
び好気槽21からの循環水を機械撹拌設備42で撹拌
し、曝気用の空気を送気せずに無酸素状態とすること
で、好気槽21で生成された硝酸性あるいは亜硝酸性窒
素を窒素ガスに還元して除去する。
In this embodiment, the mixture at the outlet of the aerobic tank 21 is circulated to the oxygen-free tank 22 by the circulation pump 141. In the anoxic tank 22, the mixed water of the sewage and the returned sludge from the anaerobic tank 20 and the circulating water from the aerobic tank 21 are stirred by the mechanical stirrer 42, and the anoxic state is achieved without sending air for aeration. As a result, the nitric or nitrite nitrogen generated in the aerobic tank 21 is reduced to nitrogen gas and removed.

【0043】凝集剤制御装置300は、図1の場合と同
様に、リン除去能力判定部301でDO値に対応するT
2時間(嫌気槽21、無酸素槽22及び好気槽21の滞
留時間)後のリン除去率を演算して予測し、予め設定さ
れている判定しきい値302と比較する。この結果、リ
ン除去率がしきい値以下であれば、生物反応槽のリン除
去はT2時間後には不良になると判定し、判定結果を凝
集剤注入制御部310に通知する。
In the coagulant control device 300, as in the case of FIG.
The phosphorus removal rate after two hours (residence time of the anaerobic tank 21, the anoxic tank 22, and the aerobic tank 21) is calculated and predicted, and is compared with a preset determination threshold value 302. As a result, if the phosphorus removal rate is equal to or less than the threshold value, it is determined that the phosphorus removal in the biological reaction tank becomes defective after T2 time, and the determination result is notified to the coagulant injection control unit 310.

【0044】凝集剤注入制御部310における凝集剤注
入量の決定は、図1の実施例の場合と同様に、予め設定
されている処理水流量当たりの凝集剤量と、処理水流量
に基づいて算出する。処理水流量は、流量計210によ
る流入水量Qi、流量計220による返送汚泥流量Qr
及び流量計230による循環水流量Qjの和となる。
The coagulant injection control unit 310 determines the coagulant injection amount based on the coagulant amount per treated water flow rate and the treated water flow rate, as in the embodiment of FIG. calculate. The treated water flow rate is the inflow water quantity Qi by the flow meter 210 and the return sludge flow rate Qr by the flow meter 220.
And the circulating water flow rate Qj by the flow meter 230.

【0045】本実施例によれば、窒素も同時に除去する
A2O法では、硝化阻害の要因となる凝集剤を必要量に
低減できるので、活性汚泥への悪影響を低減できる。
According to the present embodiment, in the A2O method in which nitrogen is also removed, the required amount of coagulant which causes nitrification inhibition can be reduced to a required amount, so that adverse effects on activated sludge can be reduced.

【0046】ところで、凝集剤注入量は放流水のリン濃
度と目標値の偏差から算出してもよい。図5に示すよう
に、凝集剤注入制御部310はリン除去不良の判定と処
理水流量Q(Qi+Qr+Qj)を受け取ると、生物反
応槽の滞留時間(T2)の経過後、沈殿池30の出口
(又は好気槽21の出口)に設けたリン濃度計240か
ら放流水のリン濃度計測値Poを取り込み、予め設定さ
れている放流水のリン濃度目標値Pmを上回る偏差分△
Pを求める。そして、処理水流量Qと偏差分△Pから、
放流水のリン濃度を目標値Pm以下に維持するのに必要
な凝集剤量を求め、凝集剤注入ポンプ150を制御す
る。これによれば、注入する凝集剤量を必要最小限に制
御できる。
Incidentally, the coagulant injection amount may be calculated from the deviation between the phosphorus concentration of the discharge water and the target value. As shown in FIG. 5, when the coagulant injection control unit 310 receives the determination of the phosphorus removal failure and receives the treated water flow rate Q (Qi + Qr + Qj), after the elapse of the residence time (T2) in the biological reaction tank, the outlet ( Alternatively, the measured value of the phosphorus concentration Po of the effluent is taken in from the phosphorus concentration meter 240 provided at the outlet of the aerobic tank 21), and the deviation amount exceeds a preset phosphorus concentration target value Pm of the effluent.
Find P. Then, from the treated water flow rate Q and the deviation ΔP,
The coagulant injection pump 150 is controlled by determining the amount of coagulant required to maintain the phosphorus concentration of the discharge water at or below the target value Pm. According to this, the amount of the coagulant to be injected can be controlled to a necessary minimum.

【0047】この場合、リン濃度計240はリン除去不
良の判定に対応する期間のみ計測し、かつ流入水DOの
計測周期より十分長い周期としてよい。これにより、連
続計測設備によらない計測器の使用を可能にする。
In this case, the phosphorus concentration meter 240 may measure only the period corresponding to the determination of the defective phosphorus removal, and may set the period sufficiently longer than the measurement period of the inflow water DO. This enables the use of a measuring instrument that does not depend on continuous measuring equipment.

【0048】[0048]

【発明の効果】本発明によれば、流入下水の溶存酸素
(DO)の計測値から水処理プラントの生物学的リン除
去能力の良否を予測できるので、リン除去能力の悪化を
補完する凝集剤の注入を適正に管理して、放流水の良好
な水質を維持する効果がある。
According to the present invention, the quality of the biological phosphorus removal capacity of a water treatment plant can be predicted from the measured value of the dissolved oxygen (DO) of the inflow sewage. This has the effect of properly managing the injection of effluent and maintaining good water quality of the effluent.

【0049】また、DOの推移から凝集剤の注入開始、
終了タイミングを把握できるので、凝集剤の注入時期を
適正に管理して必要最小限の注入量とし、運転コストと
活性汚泥への影響を低減できる効果がある。
Further, the injection of the flocculant was started based on the transition of DO,
Since the end timing can be grasped, there is an effect that the injection timing of the flocculant is appropriately controlled to the required minimum injection amount, and the operation cost and the influence on the activated sludge can be reduced.

【0050】さらに、比較的安価でメンテナンスの容易
なDO計を用いるので、既存の水処理プラントにも容易
に適用できる効果がある。
Furthermore, since the DO meter which is relatively inexpensive and easy to maintain is used, there is an effect that it can be easily applied to existing water treatment plants.

【図面の簡単な説明】[Brief description of the drawings]

【図1】本発明の一実施例を示す下水活性汚泥プロセス
の構成図。
FIG. 1 is a configuration diagram of a sewage activated sludge process showing one embodiment of the present invention.

【図2】流入水DOとリン放出量の関係を示す特性図。FIG. 2 is a characteristic diagram showing a relationship between inflow water DO and phosphorus release amount.

【図3】流入水DOとリン除去率の関係を示す特性図。FIG. 3 is a characteristic diagram showing a relationship between inflow water DO and a phosphorus removal rate.

【図4】リン放出量とリン除去率の関係を示す特性図。FIG. 4 is a characteristic diagram showing a relationship between a phosphorus release amount and a phosphorus removal rate.

【図5】本発明の他の実施例を示す下水活性汚泥プロセ
スの構成図。
FIG. 5 is a configuration diagram of a sewage activated sludge process showing another embodiment of the present invention.

【符号の説明】 15…最初沈殿池、20…嫌気槽、21…好気槽、22
…無酸素槽、30…最終沈殿池、40…散気管、41,
42…機械撹拌設備、60…返送汚泥設備、70…汚泥
返送管、80…汚泥排出管、90…余剰汚泥設備、11
0…ブロワ、130…空気管、140…循環水管、14
1…循環ポンプ、150…凝集剤注入ポンプ、151…
凝集剤タンク、200…DO計、210,220,23
0…流量計、300…凝集剤制御装置、301…リン除
去能力判定部、310…凝集剤注入制御部、320…表
示部。
[Description of Signs] 15: First sedimentation tank, 20: Anaerobic tank, 21: Aerobic tank, 22
... anoxic tank, 30 ... final sedimentation tank, 40 ... diffuser pipe, 41,
42 ... mechanical stirring equipment, 60 ... returned sludge equipment, 70 ... sludge return pipe, 80 ... sludge discharge pipe, 90 ... surplus sludge equipment, 11
0: blower, 130: air pipe, 140: circulating water pipe, 14
1. Circulating pump, 150 ... Coagulant injection pump, 151 ...
Flocculant tank, 200: DO meter, 210, 220, 23
0: flow meter, 300: flocculant control device, 301: phosphorus removal ability determination unit, 310: flocculant injection control unit, 320: display unit.

─────────────────────────────────────────────────────
────────────────────────────────────────────────── ───

【手続補正書】[Procedure amendment]

【提出日】平成10年1月19日[Submission date] January 19, 1998

【手続補正1】[Procedure amendment 1]

【補正対象書類名】明細書[Document name to be amended] Statement

【補正対象項目名】発明の名称[Correction target item name] Name of invention

【補正方法】変更[Correction method] Change

【補正内容】[Correction contents]

【発明の名称】 水処理プロセスにおける凝集剤注入制
御方法及び装置
[Title of the Invention] Coagulant injection system in water treatment process
Control method and device

【手続補正2】[Procedure amendment 2]

【補正対象書類名】明細書[Document name to be amended] Statement

【補正対象項目名】特許請求の範囲[Correction target item name] Claims

【補正方法】変更[Correction method] Change

【補正内容】[Correction contents]

【特許請求の範囲】[Claims]

【手続補正3】[Procedure amendment 3]

【補正対象書類名】明細書[Document name to be amended] Statement

【補正対象項目名】0001[Correction target item name] 0001

【補正方法】変更[Correction method] Change

【補正内容】[Correction contents]

【0001】[0001]

【発明の属する技術分野】本発明は、都市下水や産業排
水あるいは水道原水を生物学的に処理する水処理プロセ
に係わり、特に、流入水中のリンを安定に除去する
集剤注入制御方法及び装置に関する。
TECHNICAL FIELD The present invention relates to a water treatment process for biologically treating municipal sewage, industrial wastewater or tap water.
Relates to scan, in particular, coagulation stably remove phosphorus in the influent water
The present invention relates to a method and an apparatus for controlling injection of a drug .

【手続補正4】[Procedure amendment 4]

【補正対象書類名】明細書[Document name to be amended] Statement

【補正対象項目名】0012[Correction target item name] 0012

【補正方法】変更[Correction method] Change

【補正内容】[Correction contents]

【0012】本発明の目的は、上記した従来技術の状況
に鑑み、リン濃度の連続計測を使用することなく、生物
学的リン除去能力をリアルタイムに予測して、その低下
時のみ補完的に、さらには最小限に凝集剤を注入できる
水処理プロセスにおける凝集剤注入制御方法および装置
を提供することにある。
SUMMARY OF THE INVENTION In view of the state of the prior art described above, an object of the present invention is to predict biological phosphorus removal ability in real time without using continuous measurement of phosphorus concentration, and complementarily only when the ability is reduced, It is still another object of the present invention to provide a method and an apparatus for controlling the injection of a flocculant in a water treatment process capable of injecting the flocculant at a minimum.

【手続補正5】[Procedure amendment 5]

【補正対象書類名】明細書[Document name to be amended] Statement

【補正対象項目名】0014[Correction target item name] 0014

【補正方法】変更[Correction method] Change

【補正内容】[Correction contents]

【0014】上記目的を達成する本発明は、微生物を嫌
気状態、次いで好気状態とする生物反応槽の水処理プロ
セスで、流入水中の溶解性リンを過剰摂取して放流水の
リンを除去する方法において、流入水中の溶存酸素濃度
(DO)と生物学的リン除去能力を示すリン除去率の所
定関係に基づいて、サンプリングタイミング毎に計測し
た流入水のDOからリン除去率を求め、求めた除去率が
一定値以下となる場合に凝集剤を注入する間欠制御を行
なうことを特徴とする。
[0014] The present invention to achieve the above object is to remove phosphorus in effluent water by excessively taking in soluble phosphorus in influent water in a water treatment process of a biological reaction tank in which microorganisms are placed in an anaerobic state and then in an aerobic state. In the method, based on a predetermined relationship between the dissolved oxygen concentration (DO) in the inflow water and the phosphorus removal rate indicating the biological phosphorus removal ability, the phosphorus removal rate was determined from the inflow water DO measured at each sampling timing . An intermittent control for injecting a flocculant is performed when the removal rate is equal to or less than a certain value.

【手続補正6】[Procedure amendment 6]

【補正対象書類名】明細書[Document name to be amended] Statement

【補正対象項目名】0015[Correction target item name] 0015

【補正方法】変更[Correction method] Change

【補正内容】[Correction contents]

【0015】前記流入水のDOとリン除去率の所定関係
はほぼ逆比例となる。また、前記一定値以下の場合に注
入する凝集剤の量は、当該処理プロセスにおける放流水
のリン濃度の実績値に基づいて決定され、リン濃度を目
標値以下に維持できる基準凝集剤量と、前記生物反応槽
の処理水量の計測値から求める。なお、凝集剤の注入必
要時に放流水のリン濃度を測定し、目標値との差分から
注入量を決定することもできる。
The predetermined relationship between the inflow water DO and the phosphorus removal rate is substantially inversely proportional. In addition, note that
The amount of coagulant to be introduced is determined based on the actual value of the phosphorus concentration of the effluent in the treatment process, and the reference coagulant amount that can maintain the phosphorus concentration at or below the target value and the measurement of the amount of water treated in the biological reaction tank Calculate from the value. When the coagulant needs to be injected, the phosphorus concentration of the discharged water can be measured, and the injection amount can be determined from the difference from the target value.

【手続補正7】[Procedure amendment 7]

【補正対象書類名】明細書[Document name to be amended] Statement

【補正対象項目名】0017[Correction target item name] 0017

【補正方法】変更[Correction method] Change

【補正内容】[Correction contents]

【0017】さらに、上記目的を達成する本発明は、上
流側から嫌気槽と好気槽を有する生物反応槽と、その下
流の沈殿池と、前記好気槽にリン除去用の凝集剤注入装
置とを備える水処理プロセスにおいて、流入水の溶存酸
素(DO)計測手段と、該計測手段で計測したDOから
前記生物反応槽のリン除去能力の良否を判定するリン除
去判定手段と、該判定手段で能力不良と判定された場合
に前記凝集剤注入装置に凝集剤の注入指示を与える凝集
剤注入制御手段を設けたことを特徴とする。
Further, the present invention, which achieves the above object, comprises a biological reaction tank having an anaerobic tank and an aerobic tank from the upstream side, a sedimentation tank downstream thereof, and a coagulant injection device for removing phosphorus into the aerobic tank. In a water treatment process comprising: a dissolved oxygen (DO) measuring means for influent water; a phosphorus removing determining means for determining whether the phosphorus removing ability of the biological reaction tank is good from DO measured by the measuring means; Wherein the coagulant injection device is provided with a coagulant injection control means for instructing the coagulant injection device to instruct an injection of the coagulant when it is determined that the coagulant is defective.

───────────────────────────────────────────────────── フロントページの続き (72)発明者 渡辺 昭二 茨城県日立市大みか町七丁目1番1号 株 式会社日立製作所日立研究所内 (72)発明者 早坂 敏郎 東京都千代田区神田駿河台四丁目6番地 株式会社日立製作所内 (72)発明者 木村 章夫 東京都千代田区神田駿河台四丁目6番地 株式会社日立製作所内 (72)発明者 田代 義昭 東京都新宿区西新宿二丁目8番1号 (72)発明者 大沢 義行 東京都荒川区荒川八丁目25番1号 東京都 下水道局 三河島処理場内 (72)発明者 安藤 三郎 東京都足立区宮城二丁目1番14号 東京都 下水道局 小台処理場内 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shoji Watanabe 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside Hitachi, Ltd. Hitachi Research Laboratory, Ltd. (72) Inventor Toshiro Hayasaka 4-6 Kanda Surugadai, Chiyoda-ku, Tokyo Address Hitachi, Ltd. (72) Inventor Akio Kimura 4-6 Kanda Surugadai, Chiyoda-ku, Tokyo Hitachi, Ltd. (72) Yoshiaki Tashiro 2-1-1 Nishishinjuku, Shinjuku-ku, Tokyo (72) Inventor Yoshiyuki Osawa 8-25-1, Arakawa, Arakawa-ku, Tokyo Tokyo Metropolitan Sewerage Bureau Mikawashima Treatment Plant (72) Inventor Saburo Ando 2-1-1-14 Miyagi Adachi-ku Tokyo Metropolitan Government Tokyo Metropolitan Sewerage Bureau Kodai Treatment Plant

Claims (6)

【特許請求の範囲】[Claims] 【請求項1】 微生物を嫌気状態、次いで好気状態とす
る生物反応槽の水処理プロセスで、流入水中の溶解性リ
ンを過剰摂取して放流水のリンを除去する方法におい
て、 流入水中の溶存酸素濃度(DO)と生物学的リン除去能
力を示すリン除去率の所定関係に基づいて、サンプリン
グ時毎に計測した流入水のDOからリン除去率を求め、
この除去率が一定値以下となる場合に凝集剤を注入する
間欠制御を行なうことを特徴とする水処理プロセスのリ
ン除去方法。
1. A method for removing excessive phosphorus in effluent water by excessively taking in soluble phosphorus in influent water in a water treatment process of a biological reaction tank in which microorganisms are placed in an anaerobic state and then in an aerobic state. Based on a predetermined relationship between the oxygen concentration (DO) and the phosphorus removal rate indicating biological phosphorus removal ability, the phosphorus removal rate is obtained from the inflow water DO measured at each sampling time,
A method for removing phosphorus in a water treatment process, comprising: performing intermittent control of injecting a coagulant when the removal rate is equal to or less than a predetermined value.
【請求項2】 請求項1において、 前記流入水のDOとリン除去率の所定関係は、ほぼ逆比
例となることを特徴とする水処理プロセスのリン除去方
法。
2. The method for removing phosphorus in a water treatment process according to claim 1, wherein the predetermined relationship between the DO of the inflow water and the phosphorus removal rate is substantially inversely proportional.
【請求項3】 請求項1または2において、 前記凝集剤の所定量は、当該処理プロセスにおける放流
水のリン濃度の実績値に基づく基準凝集剤量と前記生物
反応槽の処理水量の計測値から求めることを特徴とする
水処理プロセスのリン除去方法。
3. The method according to claim 1, wherein the predetermined amount of the coagulant is determined from a reference coagulant amount based on the actual value of the phosphorus concentration of the effluent in the treatment process and a measured value of the treated water amount in the biological reaction tank. What is needed is a method for removing phosphorus in a water treatment process.
【請求項4】 請求項1、2または3において、 前記凝集剤の注入は当該DOの測定から所定時間後に実
行され、この所定時間は前記生物反応槽の滞留時間を目
安として予め設定されることを特徴とする水処理プロセ
スのリン除去方法。
4. The method according to claim 1, 2 or 3, wherein the injection of the flocculant is performed after a predetermined time from the measurement of the DO, and the predetermined time is set in advance based on a residence time of the biological reaction tank. A method for removing phosphorus in a water treatment process.
【請求項5】 上流側から嫌気槽と好気槽を有する生物
反応槽と、その下流の沈殿池と、前記好気槽にリン除去
用の凝集剤注入装置とを備える水処理システムにおい
て、 流入水の溶存酸素(DO)計測手段と、該計測手段で計
測したDOから前記生物反応槽のリン除去能力の良否を
判定するリン除去判定手段と、該判定手段で能力不良と
判定された場合に前記凝集剤注入装置に凝集剤の注入指
示を与える凝集剤注入制御手段を設けたことを特徴とす
る水処理システム。
5. A water treatment system comprising: a biological reaction tank having an anaerobic tank and an aerobic tank from an upstream side; a sedimentation tank downstream thereof; and a coagulant injection device for removing phosphorus in the aerobic tank. Water dissolved oxygen (DO) measuring means, phosphorus removal determining means for determining the quality of the phosphorus removing ability of the biological reaction tank from DO measured by the measuring means, and a case where the determining means determines that the capacity is poor. A water treatment system comprising a flocculant injection control unit for giving a flocculant injection instruction to the flocculant injection device.
【請求項6】 請求項5において、 前記リン除去判定手段は、前記リン除去率を求めるため
に流入水のDOとリン除去率との所定関係を演算式また
はテーブルで予め設定し、計測したDOから演算したリ
ン除去率が所定値よりも低い場合にリン除去不良と判定
することを特徴とする水処理システム。
6. The phosphorus removal determination means according to claim 5, wherein the phosphorus removal determination means sets a predetermined relationship between the inflow water DO and the phosphorus removal rate in advance by an arithmetic expression or a table to obtain the phosphorus removal rate, and measures the measured DO. A water treatment system comprising: determining a phosphorus removal failure when the phosphorus removal rate calculated from the above is lower than a predetermined value.
JP34104497A 1997-12-11 1997-12-11 Flocculant injection control method in water treatment process and device therefor Pending JPH11169887A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP34104497A JPH11169887A (en) 1997-12-11 1997-12-11 Flocculant injection control method in water treatment process and device therefor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP34104497A JPH11169887A (en) 1997-12-11 1997-12-11 Flocculant injection control method in water treatment process and device therefor

Publications (1)

Publication Number Publication Date
JPH11169887A true JPH11169887A (en) 1999-06-29

Family

ID=18342724

Family Applications (1)

Application Number Title Priority Date Filing Date
JP34104497A Pending JPH11169887A (en) 1997-12-11 1997-12-11 Flocculant injection control method in water treatment process and device therefor

Country Status (1)

Country Link
JP (1) JPH11169887A (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001353496A (en) * 2000-06-12 2001-12-25 Toshiba Corp Sewage disposal system and measuring system
JP2003190967A (en) * 2001-12-25 2003-07-08 Kurita Water Ind Ltd Crystallization and dephosphorization method and apparatus
JP2005125152A (en) * 2003-10-21 2005-05-19 Kurita Water Ind Ltd Water treatment method and water treatment apparatus
JP2007245146A (en) * 2007-03-12 2007-09-27 Toshiba Corp Sewage treatment system and measurement system
CN102153232A (en) * 2011-03-01 2011-08-17 哈尔滨工业大学 Side-flow circulation BAF (Biological Aerated Filter) intensified dephosphorization system and method for treating urban sewage with the dephosphorization system
JP2019171235A (en) * 2018-03-27 2019-10-10 株式会社九電工 Wastewater treatment apparatus

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001353496A (en) * 2000-06-12 2001-12-25 Toshiba Corp Sewage disposal system and measuring system
JP2003190967A (en) * 2001-12-25 2003-07-08 Kurita Water Ind Ltd Crystallization and dephosphorization method and apparatus
JP2005125152A (en) * 2003-10-21 2005-05-19 Kurita Water Ind Ltd Water treatment method and water treatment apparatus
JP4543656B2 (en) * 2003-10-21 2010-09-15 栗田工業株式会社 Water treatment method and water treatment apparatus
JP2007245146A (en) * 2007-03-12 2007-09-27 Toshiba Corp Sewage treatment system and measurement system
CN102153232A (en) * 2011-03-01 2011-08-17 哈尔滨工业大学 Side-flow circulation BAF (Biological Aerated Filter) intensified dephosphorization system and method for treating urban sewage with the dephosphorization system
JP2019171235A (en) * 2018-03-27 2019-10-10 株式会社九電工 Wastewater treatment apparatus

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