JPH0377460B2 - - Google Patents
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- Publication number
- JPH0377460B2 JPH0377460B2 JP20984382A JP20984382A JPH0377460B2 JP H0377460 B2 JPH0377460 B2 JP H0377460B2 JP 20984382 A JP20984382 A JP 20984382A JP 20984382 A JP20984382 A JP 20984382A JP H0377460 B2 JPH0377460 B2 JP H0377460B2
- Authority
- JP
- Japan
- Prior art keywords
- bod
- dissolved oxygen
- concentration
- measurement
- oxygen concentration
- 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.)
- Expired
Links
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 41
- 239000001301 oxygen Substances 0.000 claims description 41
- 229910052760 oxygen Inorganic materials 0.000 claims description 41
- 238000005259 measurement Methods 0.000 claims description 38
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 36
- 238000012360 testing method Methods 0.000 claims description 12
- 230000029058 respiratory gaseous exchange Effects 0.000 claims description 11
- 239000000725 suspension Substances 0.000 claims description 9
- 238000007254 oxidation reaction Methods 0.000 claims description 7
- 239000000126 substance Substances 0.000 claims description 6
- 238000000691 measurement method Methods 0.000 claims description 4
- 238000003756 stirring Methods 0.000 claims description 3
- 239000003344 environmental pollutant Substances 0.000 claims 1
- 231100000719 pollutant Toxicity 0.000 claims 1
- 239000010802 sludge Substances 0.000 description 25
- 238000000034 method Methods 0.000 description 20
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 15
- 238000005273 aeration Methods 0.000 description 12
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 5
- 238000001514 detection method Methods 0.000 description 5
- 238000012937 correction Methods 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 238000012546 transfer Methods 0.000 description 4
- WHUUTDBJXJRKMK-UHFFFAOYSA-N Glutamic acid Natural products OC(=O)C(N)CCC(O)=O WHUUTDBJXJRKMK-UHFFFAOYSA-N 0.000 description 3
- 238000004140 cleaning Methods 0.000 description 3
- 238000007796 conventional method Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 235000013922 glutamic acid Nutrition 0.000 description 3
- 239000004220 glutamic acid Substances 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 230000002123 temporal effect Effects 0.000 description 3
- WQZGKKKJIJFFOK-GASJEMHNSA-N Glucose Natural products OC[C@H]1OC(O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-GASJEMHNSA-N 0.000 description 2
- WHUUTDBJXJRKMK-VKHMYHEASA-N L-glutamic acid Chemical compound OC(=O)[C@@H](N)CCC(O)=O WHUUTDBJXJRKMK-VKHMYHEASA-N 0.000 description 2
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 2
- WQZGKKKJIJFFOK-VFUOTHLCSA-N beta-D-glucose Chemical compound OC[C@H]1O[C@@H](O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-VFUOTHLCSA-N 0.000 description 2
- 239000008103 glucose Substances 0.000 description 2
- 239000010842 industrial wastewater Substances 0.000 description 2
- 150000002894 organic compounds Chemical class 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 230000035484 reaction time Effects 0.000 description 2
- 239000010865 sewage Substances 0.000 description 2
- 239000002351 wastewater Substances 0.000 description 2
- 238000004065 wastewater treatment Methods 0.000 description 2
- DWAQJAXMDSEUJJ-UHFFFAOYSA-M Sodium bisulfite Chemical compound [Na+].OS([O-])=O DWAQJAXMDSEUJJ-UHFFFAOYSA-M 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000003869 coulometry Methods 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000005416 organic matter Substances 0.000 description 1
- 238000010979 pH adjustment Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 229940079827 sodium hydrogen sulfite Drugs 0.000 description 1
- 235000010267 sodium hydrogen sulphite Nutrition 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000010561 standard procedure Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/18—Water
- G01N33/1806—Biological oxygen demand [BOD] or chemical oxygen demand [COD]
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Food Science & Technology (AREA)
- Analytical Chemistry (AREA)
- Molecular Biology (AREA)
- Biomedical Technology (AREA)
- Biodiversity & Conservation Biology (AREA)
- Medicinal Chemistry (AREA)
- Physics & Mathematics (AREA)
- Emergency Medicine (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Activated Sludge Processes (AREA)
Description
本発明は、産業廃水その他の被処理排水の生物
化学的酸素要求量（BOD）を迅速に測定する方
法及びその装置に関するものである。
活性汚泥法による排水処理においては、BOD
は重要な管理指標であつて、その測定は適正かつ
迅速な処理を行うのに不可欠である。
このBODを測定する標準的方法においては、
初期の溶存酸素量の40〜70％が利用されるので、
それに見合つた低いBODの検水にはそのまま適
用できるが、そのBOD測定範囲があまりにも狭
く、高いBOD検水を測定するには、水で希釈す
ることが必要である。また、BODの測定範囲を
広くするための対策として、再曝気法、検圧方
式、体積補償方式などが知られているが、いずれ
もその測定に約５日間もの長時間を必要とし、そ
の測定値と５日経過後の全BODとの関係も変動
して適正かつ効率のよい汚水処理を行うことがで
きないという欠陥があつた。またBODの測定を
短期間に行うために、クーロメトリー方式によ
り、酸素摂取率の変曲点を記録紙上より求める方
法が提案されたが、この方法でも測定結果が得ら
れるまでに0.2〜２日間を要し、自動制御用出力
として利用するには不適である。連続的に排出さ
れる産業廃水などを適正かつ迅速に浄化処理し、
特に自動制御によりこれを行うには、ネツクであ
つた上記のようなBODの測定期間を大幅に短縮
し、迅速かつ正確に測定しうる方法を見出すこと
であり、そのような測定装置を開発することであ
つた。
本発明者らは、このような社会的要望に沿つて
BODを極めて迅速に測定しうる方法について鋭
意研究を重ねた結果、10〜30分程度の短時間で精
度よくBODを測定する望ましい方法及び装置を
見出し、本発明をなすに至つた。
すなわち、本発明は、測定しようとする検水中
の有機物質（BOD成分）によく馴致した活性汚
泥の懸濁液を測定容器に入れ、一定速度でかきま
ぜながら懸濁液中の溶存酸素濃度を連続的に計測
し、内性呼吸による溶存酸素濃度がほとんど
0ppmにあることを確認したのち、この中に検水
の一定量を添加して一定条件で曝気し、検水添加
時点から溶存酸素濃度が急激に増加しはじめるま
での生物化学的酸化所要時間を自動計測し、あら
かじめ作成されたBOD量とその生物化学的酸化
所要時間との関係からBOD濃度を求めることを
特徴とする迅速にBODを測定する方法及びその
測定に好適な装置として、曝気装置及びかきまぜ
機を備えたBOD測定槽、PH自動調節装置、該測
定装置内に位置する端子と並列に連結された溶存
酸素濃度自動測定装置、活性汚泥濃度自動測定装
置及びタイマを介して連結された演算部、検水添
加装置、活性汚泥供給装置から成り、上記演算部
には溶存酸素移動効率、活性汚泥内性呼吸量及び
JIS測定値換算補正係数があらかじめ挿入され、
演算結果を電送して表示、記録するための記録部
が連接された迅速BOD測定装置を提供するもの
である。
本発明の装置及びこれを用いるBOD測定方法
によれば検水の採取から、測定結果の表示まで、
すべて自動化され、測定誤差も20％以内であり、
設定された時間毎に、連続的かつ自動的に測定を
繰返し行うことができる。
本発明による迅速BOD測定結果に基いて、同
様な排水処理装置に適用し、この出力により各部
を自動制御することにより、常に浄化された処理
水が得られ、環境保全に貢献し得るものである。
次に、添付図面により本発明をさらに詳細に説
明する。
第１図は、一定量の活性汚泥を曝気しながら検
水を加えた場合のBOD濃度及び溶存酸素（DO）
濃度と経過時間との相関々係を示すグラフで、実
線はDO濃度（ppm）の時間的変化及び点線は
BOD濃度の時間的変化を示している。また図中
のＡ点は、検水の一定量を活性汚泥に注加した時
点、Ｂ点は溶存酸素濃度が実質的に最小となつた
時点、またＣ点は曝気処理において有機物の生物
処理が完了した時点で酸素の消費がなく溶存酸素
の濃度は急激に増大しはじめ、BOD濃度は最小
となつて保持される時点を指示している。
図においては、例えばある一定量の活性汚泥懸
濁液を測定装置に入れ、これを例えば0.5／
minの一定通気量で曝気しながら検水一定量を加
え（Ａ点）、曝気処理を継続する。検水添加以前
においては、曝気による溶存酸素の供給と活性汚
泥の内性呼吸による溶存酸素の消費速度との関係
から、溶存酸素濃度は３〜7ppmの範囲内のある
値で一定となる。もしこの範囲外の場合には、活
性汚泥濃度又は通気量を調節することが好まし
い。懸濁液が添加されると、BODの生物処理の
ため溶存酸素は消費され、ほとんど0ppmとなる。
一方BOD濃度はＡ点より一定速度で減少し、添
加されたBODの生物処理が完了した約３時間後
にはBOD濃度が最小となり（Ｃ点）、その最小値
に保たれるとともにDO濃度は急激に増大しはじ
める。このような操作においては、Ａ点からＣ点
までのBOD濃度は一定速度で減少し、BOD添加
量の寡多はＢ点よりＣ点までの処理時間に比例す
る。従つて一定条件下の生物化学的酸化所要時間
は検水のBOD濃度と直線関係にあり、この関係
をあらかじめ求めておけば、所要時間から容易に
BODを測定することができる。本発明はこの特
定の現象を有効に利用するものであり、検水の
BOD濃度を希薄化して時間を短縮できる。
しかし、この方法においては、例えば第１図の
グラフにみられるように、検水添加時の活性汚で
い懸濁液中の溶存酸素濃度は約6.5ppmであり、
又、測定終了時点のそれは0ppmであるので、測
定槽容量を5Lとすると、この中に含まれる溶存
酸素量は33mg（５Kg、x6.5ppm）にも達するが、
BOD物質としてメタノールを例にとり、この溶
存酸素によつて酸化されるメタノールのBOD値
を、0.98gBOD／ｇメタノールとして計算する
と、そのBOD量は約33mgに相当する。この時の
検水量を100mLと仮定すると、最終的に測定さ
れるBOD濃度の値は、後述の演算式を用いて計
算すると、約330ppm［（30mg、x0.98）／100mL
x1000mL］にも達することになり、これは、検
水量の減少に伴つてBOD測定値の負の誤差を飛
躍的に増大させる欠点を有するものである。
本件発明では、以上の問題点の克服のために、
活性汚でいの有する内性呼吸作用を利用して、反
応容器中の溶存酸素濃度をあらかじめ消費させて
0ppmとし、その時点からのばつきによつて進行
した酸化反応時間を計測することにより、反応容
器中に元々存在した溶存酸素によつてのみ進行し
た酸化反応時間部分を消去した。これにより、本
件発明は、測定誤差をほとんど含まない理想的な
方法であることは明かである。
尚、本件発明におけるBOD反応の開始及び終
了点の検出は、各々その時点での溶存酸素濃度の
値を検出することにより行われる。すなわち、開
始点の検出は、溶存酸素濃度が内生呼吸レベルか
ら0ppmとなり、ばつきが開始された時点であり、
又、終了点の検出は、溶存酸素濃度が0ppmから
内生呼吸レベルに向かつて増大した時点、例え
ば、その値が0.5ppmとなつた時点で各々好適に
行われる。
また、第２図は、本発明の測定方法を実施する
ための装置の構成を示す系統図で、BOD測定槽
１にはかきまぜ機２、及び各種検出端３，４が取
り付けられ、底部には曝気装置５から送られる空
気を放出する多数の小穴を有する部材が設置さ
れ、測定槽１は恒温槽６中に配置されている。ま
た、PH自動調節装置７は上記検出端４に連結さ
れ、他の検出端３は溶存酸素濃度測定装置８、活
性汚泥濃度計９及びタイマー１０にパラレルに連
結されて、これら８，９及び１０はさらに演算部
１１に連結されている。また検水添加装置１２、
活性汚泥採取装置１３及び測定槽洗浄装置１４
は、測定装置１内に開放口を有する管に連結さ
れ、測定装置への活性汚泥懸濁液、検水、洗浄水
の供給がこの管で行いうるように設計されてい
る。
演算部１１には、酸素移動効率、活性汚泥内性
呼吸量、測定槽容量、検水採取量、本測定値を
JIS測定値に換算するための補正係数などがあら
かじめ人為的に入力されていて、演算部は下記式
により演算を行い、得られたBODはデジタル表
示装置１５及び記録計１６に表示され記録され
る。
演算式は次のとおりである。
｛（Ｔ×Ｄ）−（Ｔ×SW×Ｂ）｝×Ｆ／Ｓ
＝BOD（ppm）
Ｔ；BOD添加より処理完了迄の時間（秒）
Ｄ；酸素移動効率（mgO2／sec）
SW；活性汚泥量（ｇ）
Ｂ；活性汚泥1gが１秒間に消費する溶存酸素
量（mgO2／sec／MLSS−ｇ）
Ｆ；本測定値をJIS測定値に換算するための補
正係数
Ｓ；検水採取量（Kg）
次に、このような構成の測定装置を用いて検水
のBODを測定する方法の概要を説明する。
内容５の測定槽１に、活性汚泥の約3000ppm
懸濁液５を検水添加装置１２で自動採取し、採
取量はレベル計にて感知し、撹拌機２（例えば新
東化学、スリーワン、モーター、600G）、溶存酸
素濃度測定装置３，８（DKK−7610型）、PH自動
調節装置４，７（DKK−6040型）、活性汚泥濃度
計３，９（DKK−SSD−20）、曝気装置５（世晃
産業、MD−30）を附設して、20℃±１℃に自動
調節された恒温水槽６（クールニツクス、CTR
−３型）中に固定する。PH、DO、活性汚泥濃
度の各測定値は、演算部１１に電送される。10ml
〜１の検水添加装置１２で検水添加と同時に曝
気工程となり、タイマー１０（オムロン、デジタ
ル、115A−4D）が稼動する。添加されたBOD源
が生物処理されると、溶存酸素濃度が増加する。
設定値（第１図、Ｃ点）に達すると、タイマー及
び曝気工程は停止し、この時間（秒）が演算回路
に電送され、上記演算式によりBODが換算され、
デジタル表示１５及び記録計１６に記録される。
続いて、洗浄装置１４により測定槽が洗浄され、
一工程は終る。
次に、上記のような構成の本発明の装置を用い
た実施例により本発明をさらに詳細に説明する。
実施例 １
各種設定条件として、BOD測定の温度は、JIS
−Ｋ−0102工場排水試験方法に準じ、20℃の恒温
水槽中で実験した。また、測定槽の容量は５と
し、活性汚泥濃度は2000ppm以下においては、測
定槽中の溶存酸素濃度を0ppmに保つことが困難
であり、また、5000ppm以上では内性呼吸による
ブランク値が高くなるため、約3000ppmとした。
PHは、7.0〜7.5の範囲に自動中和した。内性呼吸
量の測定は、内容２の密閉容器を用い常法によ
り測定した。実験結果は、10〜20mgO2／Hr・活
性汚泥1gの範囲にあつた。酸素移動効率の測定
は、亜硫酸水素ナトリウムの一定量を用いて行
い、PH７〜7.5、水温20℃測定槽容量5L、通気速
度0.5L／minの条件下では、その効率は0.09〜
0.11mgO2／secの値であつた。
用いた活性汚泥は都市下水処理場の返送汚泥を
各槽に分取し、BOD基質として酢酸、メタノー
ル、フエノール、グルコース、グルタミン酸の
各々１％溶液をそれぞれ別の水槽に添加し溶存酸
素濃度を連続計測し、BODの生物処理完了にと
もなう溶存酸素濃度の増加後、さらに追加して約
１か月間馴致したものである。
各有機化合物及びグルタミン酸とグルコースと
の等量混合物のそれぞれ１％水溶液についての
BOD測結果を次表にまとめて示す。
The present invention relates to a method and apparatus for rapidly measuring the biochemical oxygen demand (BOD) of industrial wastewater and other wastewater to be treated. In wastewater treatment using activated sludge method, BOD
is an important management indicator, and its measurement is essential for proper and prompt processing. In the standard method of measuring this BOD,
Since 40-70% of the initial amount of dissolved oxygen is utilized,
Although it can be applied as is to water samples with an appropriately low BOD, its BOD measurement range is too narrow, and it is necessary to dilute it with water to measure water with a high BOD. In addition, the reaeration method, pressure detection method, and volume compensation method are known as measures to widen the measurement range of BOD, but all of them require a long time of about 5 days to measure. The relationship between the value and the total BOD after 5 days also fluctuated, making it impossible to perform proper and efficient sewage treatment. In addition, in order to measure BOD in a short period of time, a method was proposed in which the inflection point of the oxygen uptake rate was determined from a recording paper using the coulometry method, but even with this method, it took 0.2 to 2 days to obtain the measurement results. Therefore, it is not suitable for use as an output for automatic control. Properly and quickly purify industrial wastewater that is continuously discharged,
In particular, in order to do this through automatic control, it is necessary to find a method that can significantly shorten the conventional BOD measurement period as described above and measure quickly and accurately, and to develop such a measuring device. It happened. In line with such social demands, the present inventors
As a result of intensive research on a method that can measure BOD extremely quickly, we have discovered a desirable method and device that can accurately measure BOD in a short period of about 10 to 30 minutes, and have accomplished the present invention. That is, in the present invention, a suspension of activated sludge that is well adapted to the organic substances (BOD components) in the sample water to be measured is placed in a measurement container, and the dissolved oxygen concentration in the suspension is continuously measured while stirring at a constant speed. The dissolved oxygen concentration is mostly due to internal respiration.
After confirming that the concentration is 0 ppm, a certain amount of test water is added to this and aerated under certain conditions, and the time required for biochemical oxidation from the time the test water is added until the dissolved oxygen concentration begins to increase rapidly A quick BOD measurement method characterized by automatically measuring and determining the BOD concentration from the relationship between the BOD amount prepared in advance and the time required for biochemical oxidation, and an aeration device and a suitable device for the measurement. A BOD measurement tank equipped with a stirring machine, an automatic PH adjustment device, an automatic dissolved oxygen concentration measurement device connected in parallel with the terminal located in the measurement device, an automatic activated sludge concentration measurement device, and a calculation connected via a timer. It consists of a test water addition unit, an activated sludge supply unit, and the above calculation unit calculates dissolved oxygen transfer efficiency, activated sludge internal respiration rate, and
The JIS measurement value conversion correction coefficient is pre-inserted,
The present invention provides a rapid BOD measuring device connected to a recording section for electronically transmitting, displaying, and recording calculation results. According to the device of the present invention and the BOD measurement method using the same, from collecting the sample water to displaying the measurement results,
Everything is automated and the measurement error is within 20%.
Measurements can be repeated continuously and automatically at set time intervals. By applying the rapid BOD measurement results obtained by the present invention to similar wastewater treatment equipment and automatically controlling each part using this output, purified treated water can be obtained at all times, contributing to environmental conservation. . Next, the present invention will be explained in more detail with reference to the accompanying drawings. Figure 1 shows the BOD concentration and dissolved oxygen (DO) when a certain amount of activated sludge is aerated and sample water is added.
This is a graph showing the correlation between concentration and elapsed time, where the solid line shows the temporal change in DO concentration (ppm) and the dotted line shows the temporal change in DO concentration (ppm).
It shows the temporal change in BOD concentration. In addition, point A in the figure is the point when a certain amount of sample water is poured into activated sludge, point B is the point when the dissolved oxygen concentration has reached a substantially minimum, and point C is the point when the biological treatment of organic matter is completed in the aeration process. When the process is completed, no oxygen is consumed and the dissolved oxygen concentration begins to increase rapidly, indicating the point at which the BOD concentration reaches a minimum and is maintained. In the figure, for example, a certain amount of activated sludge suspension is put into the measuring device, and this is
While aerating at a constant aeration rate of min, a certain amount of test water is added (point A) and the aeration process is continued. Before the sample water is added, the dissolved oxygen concentration is constant at a certain value within the range of 3 to 7 ppm due to the relationship between the supply of dissolved oxygen by aeration and the rate of consumption of dissolved oxygen by endogenous respiration of activated sludge. If it is outside this range, it is preferable to adjust the activated sludge concentration or aeration amount. When the suspension is added, dissolved oxygen is consumed due to biological treatment of BOD and becomes almost 0 ppm.
On the other hand, the BOD concentration decreases at a constant rate from point A, and approximately 3 hours after the biological treatment of added BOD is completed, the BOD concentration reaches its minimum (point C), and is maintained at that minimum value while the DO concentration rapidly decreases. It begins to increase. In such an operation, the BOD concentration from point A to point C decreases at a constant rate, and the amount of BOD added is proportional to the processing time from point B to point C. Therefore, the time required for biochemical oxidation under certain conditions has a linear relationship with the BOD concentration of the sample water, and if this relationship is determined in advance, it can be easily calculated from the required time.
BOD can be measured. The present invention makes effective use of this specific phenomenon, and
The time can be shortened by diluting the BOD concentration. However, in this method, for example, as shown in the graph of Figure 1, the dissolved oxygen concentration in the activated soil suspension when sample water is added is approximately 6.5 ppm.
Also, since it is 0ppm at the end of the measurement, if the measurement tank capacity is 5L, the amount of dissolved oxygen contained in it will reach 33mg (5Kg, x 6.5ppm),
Taking methanol as an example of a BOD substance, if the BOD value of methanol oxidized by this dissolved oxygen is calculated as 0.98 g BOD/g methanol, the BOD amount corresponds to about 33 mg. Assuming that the sample water volume at this time is 100 mL, the final measured BOD concentration value is approximately 330 ppm [(30 mg, x 0.98)/100 mL when calculated using the formula described below.
x1000 mL], which has the disadvantage of dramatically increasing the negative error of BOD measurement values as the amount of sampled water decreases. In order to overcome the above problems, in the present invention,
The dissolved oxygen concentration in the reaction vessel is consumed in advance by utilizing the endogenous respiration effect of activated dirt.
By setting the temperature to 0 ppm and measuring the oxidation reaction time that progressed due to fluctuations from that point, the portion of the oxidation reaction time that progressed only due to the dissolved oxygen originally present in the reaction vessel was eliminated. From this, it is clear that the present invention is an ideal method with almost no measurement errors. In the present invention, the start and end points of the BOD reaction are detected by detecting the dissolved oxygen concentration at each point in time. In other words, the starting point is detected at the point when the dissolved oxygen concentration drops from the endogenous respiration level to 0 ppm and the fluttering starts.
The end point is preferably detected at the time when the dissolved oxygen concentration increases from 0 ppm toward the endogenous respiration level, for example, when the value reaches 0.5 ppm. Moreover, FIG. 2 is a system diagram showing the configuration of an apparatus for carrying out the measurement method of the present invention, in which a stirrer 2 and various detection ends 3 and 4 are attached to the BOD measurement tank 1, and the bottom A member having a large number of small holes for releasing air sent from the aeration device 5 is installed, and the measurement tank 1 is placed in a constant temperature tank 6. Further, the PH automatic adjustment device 7 is connected to the detection end 4, and the other detection end 3 is connected in parallel to the dissolved oxygen concentration measuring device 8, the activated sludge concentration meter 9, and the timer 10. is further connected to an arithmetic unit 11. In addition, the test water addition device 12,
Activated sludge collection device 13 and measurement tank cleaning device 14
is connected to a pipe having an open port inside the measuring device 1, and is designed so that activated sludge suspension, water testing, and washing water can be supplied to the measuring device through this pipe. The calculation unit 11 stores the oxygen transfer efficiency, activated sludge internal respiration rate, measurement tank capacity, sampled water amount, and actual measured values.
Correction coefficients etc. for conversion to JIS measurement values are artificially input in advance, and the calculation section performs calculations using the following formula, and the obtained BOD is displayed and recorded on the digital display device 15 and recorder 16. . The calculation formula is as follows. {(T×D)-(T×SW×B)}×F/S = BOD (ppm) T; Time from BOD addition to completion of treatment (seconds) D; Oxygen transfer efficiency (mgO 2 /sec) SW; Activated sludge amount (g) B: Dissolved oxygen amount consumed per second by 1 g of activated sludge (mgO 2 /sec/MLSS-g) F: Correction coefficient for converting this measured value to JIS measured value S: Test water Collected amount (Kg) Next, an outline of a method for measuring BOD of sample water using a measuring device with such a configuration will be explained. Approximately 3000 ppm of activated sludge is placed in measurement tank 1 of content 5.
The suspension 5 is automatically sampled using the test water addition device 12, and the sampled amount is detected using a level meter. DKK-7610 model), PH automatic regulator 4, 7 (DKK-6040 model), activated sludge concentration meter 3, 9 (DKK-SSD-20), and aeration device 5 (Seiko Sangyo, MD-30) are attached. A constant temperature water bath 6 (Coolnics, CTR) automatically adjusted to 20℃±1℃
-3 type). The measured values of PH, DO, and activated sludge concentration are electronically transmitted to the calculation unit 11. 10ml
The aeration process starts simultaneously with the addition of test water in the test water addition device 12 of 1 to 1, and the timer 10 (Omron, Digital, 115A-4D) is activated. When the added BOD source is biologically treated, the dissolved oxygen concentration increases.
When the set value (Figure 1, point C) is reached, the timer and aeration process are stopped, this time (seconds) is sent to the calculation circuit, and the BOD is converted using the above calculation formula.
It is recorded on the digital display 15 and recorder 16.
Subsequently, the measurement tank is cleaned by the cleaning device 14,
One process is completed. Next, the present invention will be explained in more detail with reference to an example using the apparatus of the present invention configured as described above. Example 1 As various setting conditions, the temperature of BOD measurement is JIS
The experiment was conducted in a constant temperature water tank at 20°C according to the -K-0102 factory wastewater test method. In addition, the capacity of the measurement tank is 5, and when the activated sludge concentration is below 2000ppm, it is difficult to maintain the dissolved oxygen concentration in the measurement tank at 0ppm, and when it is above 5000ppm, the blank value due to endogenous respiration becomes high. Therefore, it was set at approximately 3000ppm.
PH auto-neutralized to a range of 7.0-7.5. The internal respiration rate was measured by a conventional method using a sealed container of Content 2. The experimental results were in the range of 10 to 20 mgO 2 /Hr/1 g of activated sludge. The oxygen transfer efficiency was measured using a certain amount of sodium hydrogen sulfite, and under the conditions of pH 7 to 7.5, water temperature of 20°C, measurement tank capacity of 5 L, and aeration rate of 0.5 L/min, the efficiency was 0.09 to 7.5.
The value was 0.11 mgO 2 /sec. The activated sludge used was return sludge from a municipal sewage treatment plant, which was separated into each tank, and 1% solutions each of acetic acid, methanol, phenol, glucose, and glutamic acid were added to separate water tanks as BOD substrates to continuously measure the dissolved oxygen concentration. After measuring and increasing the dissolved oxygen concentration due to the completion of biological treatment of BOD, the water was allowed to acclimate for an additional month. For each 1% aqueous solution of each organic compound and a mixture of equal amounts of glutamic acid and glucose,
The BOD measurement results are summarized in the table below.
【表】
この表には、有機化合物のBODを、本発明の
方法で測定し、文献などで公表されている従来法
と対比して示してある。容易に生物分解される酢
酸・メタノールは、従来法に近い測定値が得られ
たがグルタミン酸等は、低い測定値が得られた。
しかし、これらの化合物も再現性あり、補正する
ことにより真のBODに近い測定値が短時間に得
られることが理解されよう。[Table] This table shows the BOD of organic compounds measured by the method of the present invention in comparison with conventional methods published in literature. For acetic acid and methanol, which are easily biodegradable, measurement values close to those obtained using conventional methods were obtained, but for glutamic acid and other substances, lower measurement values were obtained.
However, it will be understood that these compounds are also reproducible, and by correction, measurements close to the true BOD can be obtained in a short time.
第１図は、BOD濃度と溶存酸素濃度と処理時
間との相関々係を示すものであり、図中Ａは検水
添加点であり、Ｂは生物処理開始点であり、Ｃは
BOD生物処理完了点を示す。第２図は、迅速
BOD測定装置の構成を示す系統図である。図中
の符号は１……測定槽、２……撹拌機、３，４…
…各種検出端、５……曝気装置、６……恒温水
槽、７…PH自動調節装置、８……溶存酸素濃度測
定装置、９……活性汚泥濃度計、１０……タイマ
ー、１１……演算部、１２……検水添加装置、１
３……活性汚泥採取装置、１４……測定槽洗浄装
置、１５……デジタル表示装置、１６……記録計
である。
Figure 1 shows the correlation between BOD concentration, dissolved oxygen concentration, and treatment time. In the figure, A is the sample water addition point, B is the biological treatment start point, and C is the biological treatment start point.
Indicates the completion point of BOD biological treatment. Figure 2 shows the rapid
FIG. 2 is a system diagram showing the configuration of a BOD measuring device. The symbols in the diagram are 1...Measurement tank, 2...Stirrer, 3, 4...
... Various detection terminals, 5 ... Aeration device, 6 ... Constant temperature water tank, 7 ... PH automatic adjustment device, 8 ... Dissolved oxygen concentration measuring device, 9 ... Activated sludge concentration meter, 10 ... Timer, 11 ... Calculation Part, 12... Test water addition device, 1
3...Activated sludge collection device, 14...Measurement tank cleaning device, 15...Digital display device, 16...Recorder.
Claims (1)
質によく馴致した活性汚でいの懸濁液を測定容器
に入れ、一定流量下でばつきしてその中の溶存酸
素濃度が内生呼吸のレベルにまで増大して一定値
を維持していることを確認後にばらつきを停止
し、それと同時に一定速度下の撹はんのみによつ
て溶存酸素供給量を減少させて活性汚でいの内生
呼吸作用を利用してその容器中の溶存酸素濃度を
ほとんどOppmまで低下させ、次に、この中に検
水の一定量を添加すると共に一定流量下でばつき
を開始し、この時点から溶存酸素濃度が急激に増
加しはじめるまでの時間を、生物学的酸化反応の
所要時間として溶存酸素電極とタイマーを用いて
自動計測することが可能な一連の工程を含む測定
装置を用いて、あらかじめこれを用いて作成され
た有機物質のBOD濃度とその生物学的酸化反応
の所要時間との関係からBOD濃度を推定するこ
とを特徴とする迅速BOD測定法。1. A suspension of activated dirt that is well adapted to the organic BOD substances in the sample water to be measured is placed in a measurement container, and the dissolved oxygen concentration in the suspension is adjusted to the level of endogenous respiration by fluttering under a constant flow rate. After confirming that the amount of dissolved oxygen has increased to a certain level and maintained a constant value, the fluctuation is stopped, and at the same time, the amount of dissolved oxygen supplied is reduced by stirring only at a constant speed, and endogenous respiration of the activated pollutant is achieved. Using this action, the dissolved oxygen concentration in the container is reduced to almost Oppm.Next, a certain amount of test water is added to the container, and fluctuation is started under a constant flow rate.From this point, the dissolved oxygen concentration is reduced. Using a measuring device that includes a series of steps that can automatically measure the time required for the biological oxidation reaction to begin to rapidly increase, using a dissolved oxygen electrode and a timer, A rapid BOD measurement method characterized by estimating the BOD concentration from the relationship between the BOD concentration of an organic substance created by organic substances and the time required for its biological oxidation reaction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20984382A JPS5999353A (en) | 1982-11-30 | 1982-11-30 | Method and apparatus for measuring bod |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20984382A JPS5999353A (en) | 1982-11-30 | 1982-11-30 | Method and apparatus for measuring bod |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5999353A JPS5999353A (en) | 1984-06-08 |
| JPH0377460B2 true JPH0377460B2 (en) | 1991-12-10 |
Family
ID=16579534
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20984382A Granted JPS5999353A (en) | 1982-11-30 | 1982-11-30 | Method and apparatus for measuring bod |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5999353A (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03111759A (en) * | 1989-09-27 | 1991-05-13 | Agency Of Ind Science & Technol | Method and apparatus for measuring bod |
| US5702951A (en) * | 1990-07-04 | 1997-12-30 | Commonwealth Scientific And Industrial Research Organisation | Continuous RBCOD measurement |
| US6106718A (en) * | 1998-07-01 | 2000-08-22 | Biochem Technology, Inc. | Enhanced denitrification process by monitoring and controlling carbonaceous nutrient addition |
| US6143246A (en) | 1998-08-18 | 2000-11-07 | Biochem Technology, Inc. | Apparatus for measuring ammonia in biochemical processes |
| US5976888A (en) * | 1998-12-07 | 1999-11-02 | Biochem Technology, Inc. | Method for measuring NOx in biochemical processes |
| KR100437662B1 (en) * | 2001-10-24 | 2004-06-30 | 조승호 | System, having multiple functions, for agitating, measuring and analyzing solution |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4953896A (en) * | 1972-09-25 | 1974-05-25 |
-
1982
- 1982-11-30 JP JP20984382A patent/JPS5999353A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5999353A (en) | 1984-06-08 |
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