JPS62262797A - Controlling method for biological nitrification process - Google Patents
Controlling method for biological nitrification processInfo
- Publication number
- JPS62262797A JPS62262797A JP61107137A JP10713786A JPS62262797A JP S62262797 A JPS62262797 A JP S62262797A JP 61107137 A JP61107137 A JP 61107137A JP 10713786 A JP10713786 A JP 10713786A JP S62262797 A JPS62262797 A JP S62262797A
- Authority
- JP
- Japan
- Prior art keywords
- nitrogen
- concentration
- nitrification
- activated sludge
- control
- 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
Links
- 238000000034 method Methods 0.000 title claims abstract description 65
- 230000008569 process Effects 0.000 title claims abstract description 12
- 239000010802 sludge Substances 0.000 claims abstract description 63
- 238000005273 aeration Methods 0.000 claims abstract description 35
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 17
- 239000002351 wastewater Substances 0.000 claims abstract description 11
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 10
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 9
- 239000001301 oxygen Substances 0.000 claims abstract description 9
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 9
- 238000009499 grossing Methods 0.000 claims abstract description 3
- JVMRPSJZNHXORP-UHFFFAOYSA-N ON=O.ON=O.ON=O.N Chemical compound ON=O.ON=O.ON=O.N JVMRPSJZNHXORP-UHFFFAOYSA-N 0.000 claims abstract 2
- MMDJDBSEMBIJBB-UHFFFAOYSA-N [O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[NH6+3] Chemical compound [O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[NH6+3] MMDJDBSEMBIJBB-UHFFFAOYSA-N 0.000 claims abstract 2
- 238000000605 extraction Methods 0.000 claims description 9
- XKMRRTOUMJRJIA-UHFFFAOYSA-N ammonia nh3 Chemical compound N.N XKMRRTOUMJRJIA-UHFFFAOYSA-N 0.000 claims description 4
- 125000001477 organic nitrogen group Chemical group 0.000 claims description 3
- 230000001590 oxidative effect Effects 0.000 claims description 2
- 241000894006 Bacteria Species 0.000 abstract description 31
- 230000001546 nitrifying effect Effects 0.000 abstract description 27
- 230000000694 effects Effects 0.000 abstract description 18
- 229940095054 ammoniac Drugs 0.000 abstract 3
- 238000007599 discharging Methods 0.000 abstract 1
- 230000003647 oxidation Effects 0.000 abstract 1
- 238000007254 oxidation reaction Methods 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 11
- 230000009471 action Effects 0.000 description 6
- 230000007423 decrease Effects 0.000 description 5
- 229910017464 nitrogen compound Inorganic materials 0.000 description 5
- 150000002830 nitrogen compounds Chemical class 0.000 description 5
- 239000007789 gas Substances 0.000 description 4
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 239000005416 organic matter Substances 0.000 description 3
- 239000010865 sewage Substances 0.000 description 3
- 239000010800 human waste Substances 0.000 description 2
- 230000029058 respiratory gaseous exchange Effects 0.000 description 2
- 238000004065 wastewater treatment Methods 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- 241000196324 Embryophyta Species 0.000 description 1
- IOVCWXUNBOPUCH-UHFFFAOYSA-M Nitrite anion Chemical compound [O-]N=O IOVCWXUNBOPUCH-UHFFFAOYSA-M 0.000 description 1
- 241000233855 Orchidaceae Species 0.000 description 1
- 235000010724 Wisteria floribunda Nutrition 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000001580 bacterial effect Effects 0.000 description 1
- 235000021167 banquet Nutrition 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 238000012851 eutrophication Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- BHEPBYXIRTUNPN-UHFFFAOYSA-N hydridophosphorus(.) (triplet) Chemical class [PH] BHEPBYXIRTUNPN-UHFFFAOYSA-N 0.000 description 1
- 239000010842 industrial wastewater Substances 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 235000015097 nutrients Nutrition 0.000 description 1
- 230000033116 oxidation-reduction process Effects 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 239000002957 persistent organic pollutant Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/10—Biological treatment of water, waste water, or sewage
Landscapes
- Activated Sludge Processes (AREA)
Abstract
Description
【発明の詳細な説明】
〔発明の属する技術分野〕
本発明は、下水、し尿、その他産業廃水などの溶存窒素
化合物を含む廃水を生物学的に浄化処理する方法、特に
、活性汚泥中の硝化菌を利用して溶存窒素化合物を酸化
態窒素に酸化することを包含する廃水の生物学的硝化プ
ロセスの制御方法に関する。DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a method for biologically purifying wastewater containing dissolved nitrogen compounds such as sewage, human waste, and other industrial wastewater, particularly for nitrification in activated sludge. The present invention relates to a method for controlling the biological nitrification process of wastewater, which involves using bacteria to oxidize dissolved nitrogen compounds to oxidized nitrogen.
近年、湖沼の富栄養化や海湾での赤潮が問題となってお
り、そのため下水やし尿などの処理では、従来からの廃
水中の有機物や浮遊物の処理に加えて、窒素化合物やり
ん化合物のような栄養塩類の除去が重要な課題となって
きた。このうちで窒素化合物の除去方法については、生
物学的除去法、アンモニアストリッピング法、イオン交
換法などが知られているが、現在では生物学的除去法が
最も有望と考えられており、次第に実用化されつつある
。In recent years, eutrophication of lakes and red tide in sea bays have become a problem, and for this reason, in the treatment of sewage and human waste, in addition to the conventional treatment of organic matter and suspended matter in wastewater, it is necessary to remove nitrogen compounds and phosphorous compounds. Removal of such nutrient salts has become an important issue. Among these methods, biological removal methods, ammonia stripping methods, ion exchange methods, etc. are known as methods for removing nitrogen compounds, but biological removal methods are currently considered to be the most promising and are gradually becoming more popular. It is being put into practical use.
この生物学的除去法は、廃水中のアンモニア態窒素（以
下ＮＨａ−Ｎとする）を硝化菌の作用により酸化態窒素
（以下Ｎｏ、−Ｎとする）に酸化する硝化工程と、該工
程により作られたＮｏ、−Ｎを脱窒菌の作用により窒素
ガスに還元する脱窒工程とにより構成された脱窒法であ
って、具体的には活性汚泥法、流動床法、回転円板法な
どの処理プロセスに組み込まれて実施されており、特に
活性汚泥法による脱窒は今後の脱窒法の主流と考えられ
ている。This biological removal method consists of a nitrification process in which ammonia nitrogen (hereinafter referred to as NHa-N) in wastewater is oxidized to oxidized nitrogen (hereinafter referred to as No, -N) by the action of nitrifying bacteria; This denitrification method consists of a denitrification process in which the produced No and -N are reduced to nitrogen gas by the action of denitrifying bacteria, and specifically, activated sludge method, fluidized bed method, rotating disk method, etc. Denitrification using activated sludge is considered to be the mainstream denitrification method in the future.
前述のように、生物学的読窒法は、硝化及び脱窒の二工
程によって構成されている。したがって、脱窒を良好に
行うためには前段の硝化を確実に行う必要がある。従来
、活性汚泥法による硝化では、このための方法として、
エアレーションタンクの溶存酸素濃度（以下Ｄｏとする
）を一定に制御した上で、水質に応じて活性汚泥濃度を
調節する方法が一般に用いられてきた。即ち、この方法
では、Ｄｏ一定制御の条件下において、エアレーション
タンクへのＮＨ，−Ｎ負荷が最大となる時刻におけるタ
ンク内のＮＨ，−Ｎ濃度を測定し、タンク全長の約３７
４の地点のＮＨ４−Ｎ濃度が１ｆｌｖ／ｌ程度となるよ
うに活性汚泥濃度を調節する。この方法は、ＮＨ４−Ｎ
負荷が安定している場合又は周期的変動を繰り返す場合
には効果的であるが、負荷変動が不規則な場合には確実
な硝化を達成できないという問題があった。また、ＮＨ
，−Ｎ負荷が低いときには、タンク前半部で硝化が終了
してしまうためエアレーション動力の浪費を招くという
欠点があった。As mentioned above, the biological nitrogen reading method consists of two steps: nitrification and denitrification. Therefore, in order to perform denitrification well, it is necessary to perform the nitrification in the first stage reliably. Conventionally, in nitrification using activated sludge method, as a method for this purpose,
A method has generally been used in which the dissolved oxygen concentration (hereinafter referred to as Do) in an aeration tank is controlled at a constant level, and then the activated sludge concentration is adjusted depending on the water quality. That is, in this method, under the condition of constant Do control, the NH and -N concentrations in the tank are measured at the time when the NH and -N loads to the aeration tank reach the maximum, and the
The activated sludge concentration is adjusted so that the NH4-N concentration at point 4 is about 1 flv/l. This method uses NH4-N
Although it is effective when the load is stable or when periodic fluctuations are repeated, there is a problem that reliable nitrification cannot be achieved when the load fluctuation is irregular. Also, NH
, -N When the load is low, nitrification ends in the front half of the tank, resulting in a waste of aeration power.
これと異なる方法として、本発明者らの提案による曝気
排ガスを利用する方法がある（特開昭６０−１２２０９
９号）。この方法は、エアレーションタンク出口付近の
曝気排ガス中のＣＯ２：ａ度及びｏ２濃度をそれぞれ空
気中のＣＯ□濃度及び０□濃度を基準として分析し、そ
れぞれの差である△ＣＯｔ及び△０□を求めた上で、そ
れぞれの商又は差を算出し、その算出結果からエアレー
ションタンク内の硝化の状況を判定し、その判定結果に
基づいてｐＨ，Ｄｏ、活性汚泥濃度などを制御するもの
である。この方法は負荷変動に追従し易い制御法である
が、サンプルガス捕集器付近のｐＨ変動が小さいという
前提条件があるため、ｐＨが変動し易いプロセスでは排
ガス中のＣｏ２濃度が不安定となり、制御が困難となる
という欠点があった。As a method different from this, there is a method using aeration exhaust gas proposed by the present inventors (Japanese Unexamined Patent Publication No. 12209-1989).
No. 9). This method analyzes the CO2:a degree and o2 concentration in the aeration exhaust gas near the aeration tank outlet using the CO□ concentration and 0□ concentration in the air as standards, respectively, and calculates the respective differences △COt and △0□. Then, the quotient or difference is calculated, the nitrification status in the aeration tank is determined from the calculation result, and the pH, Do, activated sludge concentration, etc. are controlled based on the determination result. This method is a control method that can easily follow load fluctuations, but because there is a prerequisite that pH fluctuations near the sample gas collector are small, the Co2 concentration in the exhaust gas becomes unstable in processes where the pH easily fluctuates. The disadvantage is that it is difficult to control.
さらに異なる方法としては、エアレーションタンク出口
付近の酸化還元電位（以下ＯＲＰとする）を測定し、そ
の測定値から硝化等を算出し、硝化率が所定の値となる
ようにＤｏ、活性汚泥濃度などを制御する方法が提案さ
れている。しかし、この方法はＯＲＰから硝化率を求め
る点に大きな問題がある。即ち、タンク内のＯＲＰは、
ｐＨ，Ｄｏ。A further different method is to measure the oxidation-reduction potential (hereinafter referred to as ORP) near the aeration tank outlet, calculate nitrification, etc. from the measured value, and adjust Do, activated sludge concentration, etc. so that the nitrification rate becomes a predetermined value. A method for controlling this has been proposed. However, this method has a major problem in determining the nitrification rate from ORP. That is, the ORP in the tank is
pH, Do.
有機物濃度、Ｎｏｘ−Ｎ濃度、水温などによって決まる
ため、ＯＲＰの測定値からＮｏ、−Ｎ濃度を求め、これ
を硝化率に換算しても、その信鯨性は非常に低いものと
なる。したがって、この方法を実プラントに適用するこ
とは困難であった。Since it is determined by the organic matter concentration, Nox-N concentration, water temperature, etc., even if the No and -N concentrations are calculated from the ORP measurement values and converted to the nitrification rate, the reliability is very low. Therefore, it has been difficult to apply this method to actual plants.
本発明は、これら従来法の問題を一挙に解消し、エアレ
ーションタンク内の硝化状況を的確に把握し、状況に応
じて硝化菌の活性又は濃度を制御することにより、常に
安定した硝化を可能ならしめる、活性汚泥法による生物
学的硝化プロセスの制御方法を提供することを目的とす
る。The present invention solves the problems of these conventional methods at once, accurately grasps the nitrification situation in the aeration tank, and controls the activity or concentration of nitrifying bacteria according to the situation, thereby making stable nitrification possible at all times. The purpose of this study is to provide a method for controlling the biological nitrification process using the activated sludge method.
本発明は、活性汚泥法による生物学的硝化プロセスにお
いて、エアレーションタンク出口付近のＮＨ，−Ｎ濃度
を測定し、この値が所定の値となるようにＤｏを制御し
、かつ、ＤＯの平均値が所定の値となるように活性汚泥
濃度を制御することにより、硝化菌の活性、即ち単位硝
化菌濃度あたりの硝化能力を変えるか又は硝化菌の濃度
を変えて、常に安定した硝化を達成しようとするもので
ある。In the biological nitrification process using the activated sludge method, the present invention measures the NH, -N concentration near the aeration tank outlet, controls Do so that this value becomes a predetermined value, and controls the average value of DO. By controlling the activated sludge concentration so that is a predetermined value, we can change the activity of nitrifying bacteria, that is, the nitrification capacity per unit nitrifying bacteria concentration, or change the concentration of nitrifying bacteria to achieve stable nitrification at all times. That is.
活性汚泥法における硝化では、運転条件によってエアレ
ーションタンクの硝化能力が大きく変化する。これはタ
ンク内の硝化能力が硝化菌の活性及び濃度の２つの因子
に支配されているためである。したがって、硝化プロセ
スの制御とは、この２因子の制御が可能であると同時に
最小限のエネルギーで高い硝化率を達成できるものでな
ければならない。本発明者らは、前記の要件を満足する
制御方法を種々検討した結果、エアレーションタンク内
のＮＨ，−Ｎ濃度が所定の値となるようにＤｏを制御す
ることにより硝化菌の活性の制御が可能となり、またＤ
ｏの平均値が一定となるように活性汚泥濃度を制御する
ことにより硝化菌の濃度の制御が可能となり、安定な硝
化を行うことができることを見出し、本発明に至った。In nitrification using the activated sludge method, the nitrification capacity of the aeration tank changes greatly depending on the operating conditions. This is because the nitrification ability in the tank is controlled by two factors: the activity and concentration of nitrifying bacteria. Therefore, the control of the nitrification process must be able to control these two factors and at the same time achieve a high nitrification rate with the minimum amount of energy. As a result of examining various control methods that satisfy the above requirements, the present inventors found that the activity of nitrifying bacteria can be controlled by controlling Do so that the NH and -N concentrations in the aeration tank become predetermined values. It became possible and D
It was discovered that by controlling the activated sludge concentration so that the average value of o becomes constant, the concentration of nitrifying bacteria can be controlled and stable nitrification can be performed, leading to the present invention.
以下、本発明の原理及び実施例について説明する。The principle and embodiments of the present invention will be described below.
第１図は、本発明に従う活性汚泥法による生物学的硝化
プロセスの制御方法を実施するのに用いられる具体的な
装置の構成図であって、これは処理の対象とする原水１
が流入するエアレーションタンク２、曝気処理された廃
水から活性汚泥を沈澱分離して処理水３として流出させ
る沈澱槽４、エアレーションタンク２に空気を送る散気
プロワ５、散気管６、汚泥（返送汚泥７）を返送するた
めの返送汚泥ポンプ８、余剰汚泥を抜き出すための汚泥
抜出ポンプ９、そしてエアレーションタンク２の出口付
近においてＮＨ，−Ｎ濃度を測定するＮＨ，−Ｎセンサ
ー１０、Ｄｏ濃度を測定するＤｏセンサ１１、センサの
信号に基づいて制御演算を行う制御装置１２、その信号
を受けて散気ブロワ５の回転数を調節するインバータＡ
１３、汚泥抜出ポンプ９の回転数を調節するインバータ
Ｂ１４より構成されている。FIG. 1 is a block diagram of a specific device used to carry out the method for controlling the biological nitrification process using the activated sludge method according to the present invention.
an aeration tank 2 into which activated sludge flows, a settling tank 4 where activated sludge is sedimented and separated from aerated wastewater and discharged as treated water 3, an aeration blower 5 which sends air to the aeration tank 2, an aeration pipe 6, and sludge (return sludge). 7) a return sludge pump 8 for returning sludge, a sludge extraction pump 9 for extracting excess sludge, an NH, -N sensor 10 for measuring the NH, -N concentration near the outlet of the aeration tank 2, and a Do concentration A Do sensor 11 that measures, a control device 12 that performs control calculations based on the sensor signal, and an inverter A that adjusts the rotation speed of the diffuser blower 5 in response to the signal.
13, an inverter B14 that adjusts the rotation speed of the sludge removal pump 9.
初めに、この実施例における廃水処理法を説明すると、
ＮＨ，−Ｎ又は有機態窒素のような窒素化合物と有機汚
濁物を含む原水１はエアレーションタンク２に流入し、
原水１に含まれている生物分解可能な有機物はこのエア
レーションタンク２において活性汚泥の大部分を占める
ＢＯＤ酸化菌の働きにより分解除去され、また原水１に
含まれていたＮＨ４−Ｎ及びＢＯＤ酸化蘭の働きにより
有機窒素から転換されたＮＨ，−Ｎも、このエアレーシ
ョンタンク２においても活性汚泥中に混在する硝化菌の
働きによりＮｏ、−Ｎに酸化される。First, to explain the wastewater treatment method in this example,
Raw water 1 containing nitrogen compounds such as NH, -N or organic nitrogen and organic pollutants flows into an aeration tank 2,
The biodegradable organic matter contained in the raw water 1 is decomposed and removed by the action of BOD oxidizing bacteria that make up the majority of the activated sludge in the aeration tank 2, and the NH4-N and BOD oxidized orchid contained in the raw water 1 are also decomposed and removed. NH and -N converted from organic nitrogen by the action of the activated sludge are also oxidized to No and -N in this aeration tank 2 by the action of nitrifying bacteria mixed in the activated sludge.
次にＮｏ、−Ｎを含む活性汚泥は沈澱槽４に流入し、こ
こで汚泥が重力沈降で分離され、処理水３が得られる。Next, the activated sludge containing No and -N flows into the settling tank 4, where the sludge is separated by gravity sedimentation to obtain treated water 3.
分離された汚泥は大部分が返送汚泥ポンプ８により返送
汚泥７としてエアレーションタンク２に返送されるが、
その一部が汚泥抜出ポンプ９を介して余剰汚泥１５とし
て系外に除去される。Most of the separated sludge is returned to the aeration tank 2 as return sludge 7 by return sludge pump 8.
A portion of the sludge is removed from the system as surplus sludge 15 via the sludge extraction pump 9.
硝化の制御は、ＮＨ，−Ｎセンサ１０により測定したエ
アレーションタンク出口付近におけるＮＨ，−Ｎ濃度が
所定の値（設定値ＮＨ，−Ｎ、）となるようにＤＯ及び
活性汚泥濃度を制御することによって行う。ＤＯの制御
は硝化菌の活性の制御を、そして活性汚泥濃度の制御は
硝化菌の濃度の制御を意味している。Nitrification control involves controlling DO and activated sludge concentration so that the NH, -N concentration near the aeration tank outlet measured by the NH, -N sensor 10 becomes a predetermined value (set value NH, -N). done by. Control of DO means control of the activity of nitrifying bacteria, and control of activated sludge concentration means control of the concentration of nitrifying bacteria.
まず初めに、ＤＯ制御について説明する。硝化菌の活性
制御はｐＨ，Ｄｏｓ温度などを変えることによって可能
であるが、Ｄｏ制御が実用的である。First, DO control will be explained. The activity of nitrifying bacteria can be controlled by changing pH, DoS temperature, etc., but Do control is practical.
ｐＨ制御を行うためにはアルカリの添加が必要となり、
これは下水のように大量の廃水を処理する場合コスト上
昇となり、望ましくない。また、廃水の温度を変えるこ
とは、通常はエネルギー的に実現不可能である。一方、
Ｄｏ制御はエアレーションタンクにおいて広（行われて
いる方法で、コストも他の２法と比べて安価である。Ｄ
Ｏ制御による硝化菌の活性（比増殖速度）制御の原理は
、硝化菌の活性が底ＤＯ域においてＤＯ律律速れること
にある。In order to control pH, it is necessary to add alkali.
This is undesirable because it increases costs when treating a large amount of wastewater such as sewage. Also, changing the temperature of wastewater is usually not energetically feasible. on the other hand,
Do control is a widely used method in aeration tanks and is cheaper than the other two methods.D
The principle of controlling the activity (specific growth rate) of nitrifying bacteria through O control is that the activity of nitrifying bacteria is rate-limited by DO in the bottom DO region.
第２図は、この硝化菌の活性とＤｏとの関係を示す図で
あって、代表的な硝化菌である亜硝酸菌の活性はＤ０２
■／ｌ以下においてＤＯ？ａ度に律速されることを示し
ている。したが、て、ＤＯをＯ〜２ Ｎ ／ Ｉ！に制
御することにより硝化菌の活性が制御可能である。Figure 2 is a diagram showing the relationship between the activity of nitrifying bacteria and Do, and the activity of nitrite bacteria, which is a typical nitrifying bacteria, is D02.
■ DO below /l? This shows that the rate is determined by a degree. However, the DO was O~2 N/I! The activity of nitrifying bacteria can be controlled by controlling the
以上の原理を応用した硝化プロセスの制御方法を第３図
の記載も含めて説明する。第３図は、エアレーションタ
ンク２内におけるＮＨ４−Ｎ？Ｍ度、Ｄ ＯｔＭ度の関
係を示す概念図である。エアレーションタンク出口付近
（人口より全長の約３／４の地点）を硝化終了点（制御
点）Ｐとし、ここにＮＨ，−Ｎセンサ１０、ＤＯセンサ
１１が設置されている。ＮＨ，−Ｈの設定値をＮＨ４−
Ｎ。A method for controlling the nitrification process applying the above principle will be explained, including the description in FIG. Figure 3 shows NH4-N? in the aeration tank 2. It is a conceptual diagram showing the relationship between M degree and D OtM degree. A nitrification end point (control point) P is set near the aeration tank exit (a point about 3/4 of the total length from the population), and an NH, -N sensor 10 and a DO sensor 11 are installed here. Change the setting value of NH, -H to NH4-
N.
（通常１■／１）測定値をＮＨ４−Ｎ、とする。(Usually 1/1) Let the measured value be NH4-N.
また、ＤＯの設定値をＤＯｓＩ（通常１〜２■／１）、
測定値をＤｏ、とする。制御方法は、カスケート制御で
あって、ＮＨ４−Ｈ，が設定値Ｎ Ｈａ−Ｎ、となるよ
うにＤｏの測定値Ｄｏ、、を調節し、ＤＯｌをＤＯ□に
制御する。個々のフィードバックループの制御動作はＰ
Ｉ動作とする。この制御方法の具体的な意味を第３図を
用いてさらに説明すると、今ＤＯ，＝１■／１でＤＯプ
ロフィールはｂであるとする。このＤＯプロフィールは
、エアレージ日ンタンク内にて一般的に観察されるタン
ク長さ方向へＤＯ分布であって、タンク入口付近では負
荷が高く、活性汚泥の呼吸速度も高いため低く、出口に
近づくにつれて処理が進むため高く傾向がある。特に、
硝化が終了する地点では、活性汚泥の呼吸速度が急減す
るためＤｏは急に高くなる性質がある。ここで、ＮＨ４
−Ｎの流入量が増加した場合を考えると、必要な操作は
空気流量を増加させてＤＯを上げ、硝化菌の活性を高め
て、ＮＨ４−Ｎの増加分も含めて硝化し、ＮＨ４−Ｎ、
を設定値ＮＨ，−Ｎ、に保つことである。Also, set the DO setting value to DOsI (usually 1 to 2 / 1),
Let the measured value be Do. The control method is cascade control, in which the measured value Do of Do is adjusted so that NH4-H becomes the set value N Ha-N, and DOl is controlled to be DO□. The control action of each feedback loop is P
I operation. To further explain the specific meaning of this control method using FIG. 3, it is assumed that DO,=1/1 and the DO profile is b. This DO profile is a DO distribution in the length direction of the tank that is generally observed in an aerage tank, and is low near the tank inlet due to the high load and high respiration rate of activated sludge, and as it approaches the outlet. It tends to be high as processing progresses. especially,
At the point where nitrification ends, the respiration rate of activated sludge suddenly decreases, so that Do suddenly increases. Here, NH4
- Considering the case where the inflow of N increases, the necessary operations are to increase the air flow rate to raise DO, increase the activity of nitrifying bacteria, and nitrify including the increased amount of NH4-N. ,
is maintained at the set value NH, -N.
これは、Ｄｏ□を増加方向に調節し、ＤＯプロフィール
がａとなるようにＤＯ制御を行うことによって可能とな
る。逆に負荷が減少した場合には、ＤＯプロフィールを
Ｃとすればよい。このような制御が前述のカスケード制
御の具体的な動作であって、負荷変動に対応した制御方
法である。This is possible by adjusting Do□ in an increasing direction and controlling DO so that the DO profile becomes a. Conversely, if the load decreases, the DO profile may be set to C. Such control is a specific operation of the above-mentioned cascade control, and is a control method that responds to load fluctuations.
第１図において前述の制御方法を装置との関係で説明す
ると、ＮＨ，−Ｎ、はＮＨ，−Ｎセンサ１０、ＤＯｌは
Ｄｏセンサ１１を用いて測定され、測定値が制御装置１
２に入力される。ＮＨ４Ｎセンサ１０としてはアンモニ
ウムイオン選択性電極、ＤＯセンサ１１としてはＤｏ電
極を用いればよい。制御装置１２においては前述のカス
ケード制御による演算が行われ、その出力によってイン
バータＡ１３を介して散気ブロワ５の回転数が変えられ
、エアレーションタンク２への空気流量が調節される。To explain the above-mentioned control method in relation to the apparatus in FIG.
2 is input. An ammonium ion selective electrode may be used as the NH4N sensor 10, and a Do electrode may be used as the DO sensor 11. In the control device 12, the above-mentioned cascade control calculation is performed, and the rotation speed of the aeration blower 5 is changed via the inverter A13 based on the output thereof, and the air flow rate to the aeration tank 2 is adjusted.
か（して、Ｄ ＯＩＩ ’＋Ｂが行われ、Ｎ Ｈ４−Ｎ
濃度ＮＨ，−Ｎ、は設定値ＮＨａ−Ｎ、に保たれる。こ
の制御方法をブロック線図で示すと第４図のようになる
。第４図は、後述の余剰汚泥抜出流量制御も含めた本発
明の制御方法のブロック線図である。カスケード制御に
よる硝化制御が第４図の上段にようなブロック線図とな
ることは今までの説明より明らかである。(Then, D OII '+B is performed, and N H4-N
The concentration NH,-N is maintained at a set value NHa-N. This control method is shown in a block diagram as shown in FIG. FIG. 4 is a block diagram of the control method of the present invention, including excess sludge extraction flow rate control, which will be described later. It is clear from the above explanation that the nitrification control by cascade control has a block diagram as shown in the upper part of FIG. 4.
次に、硝化菌の濃度制御、即ち活性汚泥濃度制御につい
て説明する。余剰汚泥抜出装置をほぼ一定に保ち、前述
のＤＯ制御を長期間続けていると、水温が下がる冬期に
おいては低負荷でもＤｏび設定値ＤＯ３１が上昇し、高
ＤＯ運転となってしまう。Next, concentration control of nitrifying bacteria, that is, activated sludge concentration control will be explained. If the surplus sludge removal device is kept almost constant and the above-mentioned DO control is continued for a long period of time, the DO and set value DO31 will rise even under low load in the winter when the water temperature drops, resulting in high DO operation.
これは、水温の低下に帰因した硝化菌の活性低下により
高Ｄ○でなければ硝化が終了しない状態となったもので
あって、ＮＨ，−Ｎ負荷が高いときには一部のＮＨ，−
Ｎがエアレーションタンク２から流出することもある。This is because nitrification cannot be completed unless the D○ is high due to a decrease in the activity of nitrifying bacteria due to a decrease in water temperature, and when the NH, -N load is high, some NH, -
N may also flow out from the aeration tank 2.
一方、水温の高い夏期においては逆の状態となり、Ｄｏ
□が小さくなる。On the other hand, in the summer when the water temperature is high, the situation is reversed and Do
□ becomes smaller.
Ｄ Ｏ−＋が高い状態には、硝化能力の不足に加えて曝
気エネルギーの消費であり、底Ｄｏ□は処理水質の悪化
を招くため、年間を通じてＤｏ、、がほぼ一定であるこ
とが望ましい。これを実現するために余剰汚泥抜出流量
を操作して活性汚泥濃度制御を行う。この方法は、余剰
汚泥抜出流量を大きくすればエアレーションタンク２内
の活性汚泥の汚泥滞留時間（以下５ＲＴ）が長くなって
活性汚泥濃度、ひいては硝化菌濃度が増加し、逆に小さ
くすれば硝化菌濃度が減少することに基づいている。When D O-+ is high, in addition to insufficient nitrification capacity, aeration energy is consumed, and the bottom Do□ leads to deterioration of treated water quality, so it is desirable that Do is approximately constant throughout the year. To achieve this, the activated sludge concentration is controlled by manipulating the excess sludge extraction flow rate. In this method, if the excess sludge extraction flow rate is increased, the sludge residence time (hereinafter referred to as 5RT) of activated sludge in the aeration tank 2 will be lengthened, and the activated sludge concentration and eventually the nitrifying bacteria concentration will increase; It is based on a decrease in bacterial concentration.
この制御方法はフィードバック制御により、年間を通じ
て維持したいＤＯを設定値Ｄｏ、□（通常１〜１．５ｍ
ｇ／ ｌ ）とし、制御量としてＤＯ１，を平滑化した
値、例えばＤｏ□の移動平均Ｄｏ、ｖを用い、これら２
つの値の差を制御偏差としてＰＩ制御することにより余
剰汚泥抜出流量を操作する。This control method uses feedback control to set the DO that you want to maintain throughout the year to a set value Do, □ (usually 1 to 1.5 m
g/l), and using the smoothed value of DO1 as the control amount, for example, the moving average Do,v of Do□, these two
The surplus sludge extraction flow rate is controlled by performing PI control using the difference between the two values as a control deviation.
具体的には、Ｄ□、、＞ＤＯｓｚとなれば、抜出減量を
減じ、Ｄ Ｏａ ｖ ＞ Ｄ ＯＳ ｔとなれば、抜出
流量を増して、Ｄｏ□がＤＯ□に追従するような運転を
行えばよい。Specifically, if D□,, > DOsz, reduce the withdrawal loss, and if D Oav > DOS t, increase the withdrawal flow rate and operate so that Do□ follows DO□. All you have to do is
第１図において活性汚泥濃度制御を装置との関係で説明
すると、制御装置１２内部ではＤＯｓ＋の平滑化演算及
びＰＩ制御演算が行われ、その出力によってインバータ
Ｂ１４を介して汚泥抜出ポンプ９の回転数が変えられ、
余剰汚泥１５の抜出流量が調節される。かくして、活性
汚泥濃度制御、ひいては硝化菌濃度制御が行われ、Ｄｏ
設定値ＤＯ，ｌの平均値は一定に保たれ、安定した硝化
が可能となる。なお、以上は水温が変化した場合を例と
して説明したが、ＮＨ，−Ｎ負荷が長期的に変動する場
合にも、活性汚泥濃度制御は有効に機能する。第４図下
段には活性汚泥濃度制御のブロック線図を示し、上段と
１合せて本発明の制御方法のブロック線図とした。To explain activated sludge concentration control in relation to the device in FIG. 1, smoothing calculation of DOs+ and PI control calculation are performed inside the control device 12, and the output thereof is used to rotate the sludge extraction pump 9 via the inverter B14. The number can be changed,
The extraction flow rate of excess sludge 15 is adjusted. In this way, the concentration of activated sludge and, in turn, the concentration of nitrifying bacteria are controlled, and the Do
The average value of the set value DO,l is kept constant, allowing stable nitrification. In addition, although the case where the water temperature changes has been explained above as an example, the activated sludge concentration control functions effectively even when the NH, -N load fluctuates over a long period of time. The lower part of FIG. 4 shows a block diagram of activated sludge concentration control, which together with the upper part constitutes a block diagram of the control method of the present invention.
本発明によれば、エアレーションタンク出口付近にＮＨ
，−Ｎセンサ１０及びＤＯセンサ１１を設置してＮＨ，
−Ｎ濃度が所定の値となるようにＤＯ制御を行うことと
したので、硝化菌の活性制御が容易に可能となり、ＮＨ
，−Ｎ負荷が変動する場合にも安定した硝化を達成でき
る。また、Ｄｏの平均値が一定となるように活性汚泥濃
度制御を行うこととしたので、硝化菌の濃度制御が容易
に可能となり、長期的な水温、ＮＨ４−Ｎ負荷の変動に
対しても安定した硝化を達成できる。さらに、Ｄｏの平
均値を一定に制御することにより曝気動力の省エネ、処
理水質の安定化を図ることができる。According to the present invention, NH
, -N sensor 10 and DO sensor 11 are installed and NH,
- Since we decided to perform DO control so that the N concentration is at a predetermined value, it is possible to easily control the activity of nitrifying bacteria, and the NH
, -N stable nitrification can be achieved even when the N load fluctuates. In addition, since we decided to control the activated sludge concentration so that the average value of Do remains constant, the concentration of nitrifying bacteria can be easily controlled and is stable against long-term fluctuations in water temperature and NH4-N load. nitrification can be achieved. Furthermore, by controlling the average value of Do to a constant value, it is possible to save energy in aeration power and stabilize the quality of treated water.
第１図は本発明に従う廃水処理系の実施例の構成図であ
り、第２図は硝化菌の活性とＤＯの関係を示すグラフで
あり、第３図はエアレーションタンク内におけるＮＨ４
−Ｎ濃度とＤＯ濃度との関係を示す概念図であり、第４
図は本発明に従う制御系のブロック線図である。
１・・・原水、２・・・エアレーションタンク、１０・
・・ＮＨ４−Ｎセンサ、１１・・・ＤＯセンサ、１２・
・・制御装置、１５・・・余剰汚泥
特許出願人 富士電機株式会社
箋Ｚ目
ノフ０ （７１１１７１）
宴３０Fig. 1 is a block diagram of an embodiment of the wastewater treatment system according to the present invention, Fig. 2 is a graph showing the relationship between the activity of nitrifying bacteria and DO, and Fig. 3 is a graph showing the relationship between nitrifying bacteria activity and DO.
- FIG. 4 is a conceptual diagram showing the relationship between N concentration and DO concentration;
The figure is a block diagram of a control system according to the present invention. 1... Raw water, 2... Aeration tank, 10.
・・NH4-N sensor, 11・DO sensor, 12・
...control device, 15...surplus sludge patent applicant Fuji Electric Co., Ltd. paper Z-nofu 0 (711171) banquet 30
Claims (1)
窒素である亜硝酸態窒素又は硝酸態窒素に酸化すること
を包含する活性汚泥法による廃水の生物学的硝化法にお
いて、エアレーションタンク内又は処理水中のアンモニ
ア態窒素濃度及び溶存酸素濃度を測定し、アンモニア態
窒素濃度が所定の値となるように空気流量を操作して溶
存酸素濃度を制御し、該溶存酸素濃度又は溶存酸素濃度
設定値の平滑化信号が所定の値となるように余剰汚泥抜
出流量を操作して活性汚泥濃度を制御することを特徴と
する生物学的硝化プロセスの制御方法。1) In the biological nitrification method of wastewater using the activated sludge method, which involves oxidizing ammonia nitrogen and organic nitrogen in wastewater to nitrite nitrogen or nitrate nitrogen, which is an oxidized nitrogen, in an aeration tank or The ammonia nitrogen concentration and dissolved oxygen concentration in the treated water are measured, and the dissolved oxygen concentration is controlled by manipulating the air flow rate so that the ammonia nitrogen concentration becomes a predetermined value, and the dissolved oxygen concentration or dissolved oxygen concentration set value is determined. 1. A method for controlling a biological nitrification process, comprising controlling an activated sludge concentration by manipulating a surplus sludge extraction flow rate so that a smoothing signal of the sludge reaches a predetermined value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61107137A JPS62262797A (en) | 1986-05-10 | 1986-05-10 | Controlling method for biological nitrification process |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61107137A JPS62262797A (en) | 1986-05-10 | 1986-05-10 | Controlling method for biological nitrification process |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS62262797A true JPS62262797A (en) | 1987-11-14 |
Family
ID=14451447
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61107137A Pending JPS62262797A (en) | 1986-05-10 | 1986-05-10 | Controlling method for biological nitrification process |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62262797A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006192382A (en) * | 2005-01-14 | 2006-07-27 | Mitsubishi Electric Corp | Water treatment system |
| JP2008501500A (en) * | 2004-06-02 | 2008-01-24 | オテヴェ・ソシエテ・アノニム | Water treatment method using bioreactor and corresponding apparatus in which the speed of the air continuously injected into the reactor is adjusted |
| JP2011092942A (en) * | 2011-02-17 | 2011-05-12 | Kurita Water Ind Ltd | Nitrogen-containing wastewater treatment method and treatment apparatus |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5992096A (en) * | 1982-11-19 | 1984-05-28 | Fuji Electric Co Ltd | Biological nitrification of waste water |
-
1986
- 1986-05-10 JP JP61107137A patent/JPS62262797A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5992096A (en) * | 1982-11-19 | 1984-05-28 | Fuji Electric Co Ltd | Biological nitrification of waste water |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008501500A (en) * | 2004-06-02 | 2008-01-24 | オテヴェ・ソシエテ・アノニム | Water treatment method using bioreactor and corresponding apparatus in which the speed of the air continuously injected into the reactor is adjusted |
| JP2006192382A (en) * | 2005-01-14 | 2006-07-27 | Mitsubishi Electric Corp | Water treatment system |
| JP2011092942A (en) * | 2011-02-17 | 2011-05-12 | Kurita Water Ind Ltd | Nitrogen-containing wastewater treatment method and treatment apparatus |
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