JPH04243598A - Controlling method for active sludge treatment - Google Patents

Abstract

PURPOSE:To achieve high performance in the treatment of an active sludge by estimating a F/M ratio (organic substance/active sludge in waste water) which is operated on the basis of estimated values with respect to a water inflow, an ORP, a MLSS and an ATU-Rr (arylthiourea respiratory ratio) and an ATP (adenosine-3-phosphate) in an aeration tank. CONSTITUTION:A CODCR.ATP load is estimated with an ORP meter 5 (oxidation-reduction potentiometer) and a first determined data operating apparatus 3a. An ATP value then is estimated with an ATU-Rr meter 6, said CODCR.ATP load estimated value and a second determined data operating apparatus 3b. Furthermore, at an estimation part 4, a CODCR.MLSS load, a CODCR volume load, a CODCR of an inflowing water and a CODCR of a water to be treated are estimated by using said ATP estimated value, said CODCR.ATP load estimated value, a MLSS meter 8 (sludge concentration meter), an inflowing water meter 7 and a third determined data operating apparatus 3c, to produce an estimated F/M ratio. As the result, high performance can be achieved in the treatment of an active sludge.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an activated sludge treatment control method that is effective for use in activated sludge treatment of sewage, etc.

0002

BACKGROUND OF THE INVENTION In recent years, research on automation and optimization of sewage activated sludge treatment systems has progressed and has been put into practical use. The targets are mainly divided into oxygen consumption control and sludge level control. The former is control using the amount of air blown as an operating factor, and the latter is control using the amount of surplus sludge or the amount of returned sludge as an operating factor.

DO meters (dissolved oxygen concentration meters), MLSS meters (mixed liquid suspended solids concentration meters), and the like are generally used as water quality sensors for performing these controls. Furthermore, recently, an Rr meter (respirometer) and an ATU-Rr meter (allylthiourea respirator) have been developed as sensors for measuring oxygen consumption. The ATU-Rr meter measures the oxygen consumption rate (respiration rate), which is related only to the oxidation of organic substrates, by adding ATU (allylic lithiourea) to inhibit the activity of nitrifying bacteria and suppressing nitrification.

On the other hand, ATP (adenomine-
A technique for measuring 3-phosphate (3-phosphate) using a bioluminescence method has been developed, and reports have been published discussing the correlation with other water quality factors. Although a decrease in ATP is associated with a decrease in the processing performance of the aeration tank, the usefulness of ATP as a water quality indicator is not yet recognized.

[0005]

[Problem to be solved by the invention] In activated sludge treatment of sewage, controlling the ratio of activated sludge (microorganisms M) to organic matter (food F) in wastewater, that is, the F/M ratio, within a certain range stabilizes the quality of treated water. This is necessary to make the world a better place. Currently, the typical expression method for F/M ratio is MLS as microbial concentration.
S, organic matter concentration has BOD/MLSS loading using BOD. However, since it takes a long time to measure BOD, it is inconvenient to use for activated sludge treatment control.

[0006] In SRT control, which is currently in practical use as an F/M ratio control method, SRT (sludge retention time) depends on the F/M ratio in a steady state. is controlled. However, for short-term fluctuations in influent water quality and flow rate, SRT
It is difficult to control the F/M ratio by control. Further, until now, there is no known sensor that can directly measure the F/M ratio quickly and with high precision.

Although it is possible to measure the F/M ratio using the correlation between Rr and ATU-Rr and the organic volume load (BOD volume load, COD volume load), the respiration rate is determined by the F/M ratio. In addition, it is affected by factors such as temperature, and the estimation accuracy is not very high, so it cannot be said to be a highly useful F/M ratio estimation method. Furthermore, although the inflow water quality can be estimated from the F/M ratio, there is no known method for estimating the treated water quality as well.

[0008] As a method of expressing the F/M ratio in activated sludge treatment, it is conceivable to use CODcr/ATP load as an alternative to the conventional BOD/MLSS load. This is the CO flowing in per day per ATP equivalent number in the aeration tank.
Dcr is expressed in kg, but CODcr and ATP cannot be measured online automatically at present and it takes 2 to 3 hours to measure, so it is still a practical F/
It cannot be said to be an M-ratio expression method.

[0009] In addition, as a first method, CODcr・A, which is one of the expression methods of F/M ratio in activated sludge treatment, is used.
Possible methods include a method of estimating the F/M ratio from the TP load and the ATU-Rr and ATP concentration of the aeration tank, and a method of estimating the inflow water CODcr and the treated water CODcr. This method is based on correlation analysis of experimental data.
ODcr/ATP load and CODcr removal rate/AT
This method utilizes the correlation recognized between the three P.

[0010] Also, as a second method, ORP of the aeration tank
There is a method of estimating CODcr/ATP load from (oxidation-reduction potential) and a method of estimating inflow water CODcr and treated water CODcr by measuring ATP concentration. This method is based on correlation analysis of experimental data.
It utilizes the correlation found between P load and CODcr removal rate/ATP.

[0011] The first and second methods described above have the advantage that they not only enable highly reliable F/M ratio estimation over a relatively wide temperature range, but also enable estimation of treated water CODcr. ing. However, in order to estimate the F/M ratio or estimate the inflow water CODcr and treated water CODcr,
It is necessary to measure the ATP concentration in the aeration tank. Also, ATP
To date, no online automatic measuring device has been developed for measuring this, so we have to rely on manual analysis, which has the disadvantage of taking about an hour to complete. Another problem that cannot be ignored is that the reagents for measurement are quite expensive, chemically unstable, and cannot be stored for long periods of time if made into a solution, so they must be handled with care.

[0012] Under constant SRT conditions, ATP does not undergo rapid changes unless there is an influx of toxic substances.
If the measurement is performed at a frequency of about once a day, it can be used as calculation data for the F/M ratio estimation system. however,
If ATP changes rapidly, it becomes impossible to estimate the F/M ratio or estimate the inflow water CODcr and treated water CODcr. Therefore, if it is possible to omit the measurement of ATP and estimate the F/M ratio and the inflow water CODcr and treated water CODcr using the measurement data from an online automatic measuring device, the F/M ratio estimation will be more effective. It becomes a system.

The present invention was made in view of the above-mentioned problems, and its purpose is to improve the amount of water flowing into the aeration tank, the ORP value, MLSS value, ATU-Rr value, and ATU-Rr value in the aeration tank.
It is an object of the present invention to provide a high-performance activated sludge treatment control method by calculating and estimating the F/M ratio based on the TP estimated value.

[0014]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides ORP, which is the oxidation-reduction potential in the aeration tank.
The CODcr/ATP load is estimated by calculation based on the CODcr/ATP load, and the CODcr/ATP load is calculated based on this CODcr/ATP load estimate and the ATU-Rr value which is the allylthiourea respiration rate in the aeration tank. While estimating a certain ATP value, the ATP value, the value of ATU-Rr which is the allylthiourea respiration rate in the aeration tank, the inflow amount of inflow water flowing into the aeration tank, and M which is the activated sludge concentration
Calculate the CODcr volumetric load, COD based on the LSS value.
cr・MLSS load, inflow water CODcr which is oxygen consumption amount due to potassium dichromate oxide in inflow water, and treated water C
Estimate ODcr.

[0015]

[Action] OR in the aeration tank in sewage activated sludge treatment
P (redox potential) is measured, and CODcr/ATP load is calculated using the correlation with CODcr/ATP load, which is one of the expression methods of F/M ratio, and ATU-Rr in the aeration tank is measured. , ATU-Rr/ATP and C
ATP is calculated using the correlation between ODcr and ATP load. The inflow water CODcr is calculated based on the CODcr/ATP load and the estimated ATP value. Next, the correlation between CODcr removal rate/ATP and CODcr/ATP load and AT
The CODcr removal rate is calculated based on the P estimated value, and the treated water CODcr is calculated from the inflow water CODcr estimated value and the CODcr removal rate estimated value. In this way, ORP
The F/M ratio is estimated by calculating CODcr/ATP load, inflow water CODcr, and treated water CODcr from the ATU-Rr measurement value.

[0016]

Embodiments An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 shows an F/M ratio estimation system for carrying out the activated sludge treatment control method according to an embodiment of the present invention. In FIG. 1, 1 is an aeration tank, 2 is a settling tank, and 3 is a calculation unit. , 4 is an estimation processing unit.

According to the system shown in FIG. 1, inflow water is led to an aeration tank 1, aerated in the aeration tank 1, and then led to a settling tank 2. In the sedimentation tank 2, the sludge is settled and then discharged to a subsequent stage as treated water. The precipitated sludge is returned to the aeration tank 1 as return sludge and is also discharged as surplus sludge.

The arithmetic unit 3 calculates OR which is the flow rate value of the inflow water before it flows into the aeration tank 1 and the oxidation-reduction potential in the aeration tank 1.
P value, ATU-Rr (allylthiourea respiration rate) value and MLSS (activated sludge concentration) value, and AT of excess sludge
A predetermined calculation is performed using the P value as an input, and the estimation processing unit 4 performs the necessary estimation based on the calculation result.

That is, as shown in FIG.
are a first measurement data calculation unit 3a that receives the measurement data of the ORP meter 5, a second measurement data calculation unit 3b that receives the measurement data of the ATU-Rr meter 6, measurement data of the inflow water meter 7, The third input is the measurement data of 8 MLSSs.
The estimation processing section 4 consists of a first measurement data calculation section 3c.
CODcr based on the calculation data of the measurement data calculation section 3a.
- The first estimation processing unit 4a that estimates the ATP load, and the AT
Measurement data of the U-Rr meter 6 and C of the first estimation processing section 4a
A third estimation processing unit 4b that estimates ATP based on the calculation result by the second measurement data calculation unit 3b based on the estimation result of the ODcr/ATP load, the measurement data of the inflow water meter 7, and the measurement of the MLSS total 8 Data and second estimation processing unit 4
Estimated result ATP of a and second measurement data calculation unit 3b
CODcr volumetric load, CODcr/MLSS load, inflow water CODcr
and a third estimation processing section 4c that estimates the treated water CODcr.

In a continuous indoor experiment using artificial sewage for activated sludge treatment, influent water CODcr and treated water CODc were measured under constant SRT (sludge retention time) control conditions (4 days and 10 days).
r, the results of measuring ATP and ORP in the aeration tank,
A correlation was found between ORP, CODcr/ATP load, and CODcr removal rate/ATP, and the relational expression (
1) to (3) were obtained.

[0022]ORP=-427.52CODcr・AT
P load +182.6...(1) Here, correlation coefficient r = -0.8977, water temperature is 15 to 17 degrees Celsius, SRT is 4 days and 10 days, ATU-Rr/A
TP=19.65CODcr・ATP load-0.62...
...(2) Here, r=0.9927, water temperature is 15 to 17℃, S
RT is 4 days, 10 days, CODcr removal rate/ATP = 0
．． 7704×CODcr・ATP load+0.016…(
3) Here, r=+0.9927, water temperature is 15 to 17℃,
SRT is 4th and 10th.

Furthermore, the arithmetic unit 3 measures the ORP and calculates the CODcr/ATP load from equation (1). Next, from the CODcr/ATP load and ATU-Rr measurement values (
2) Calculate ATP concentration using the formula.

Next, CODcr/ATP load, aeration tank A
Based on the TP concentration and the amount of inflow water, the inflow water CODc is calculated by equation (4).
r is calculated.

[0025] Influent water CODcr (mg/l) = {COD
cr・ATP load (kg・CODcr/m・mole・
days) x aeration tank ATP concentration (m・mole/m3) x aeration tank capacity (m3)}/{inflow water amount per day x 10-3 (
m3/day)} ...(4) Treated water CODcr is CODcr/ATP load and aeration tank A
The estimated value of TP concentration is substituted into equation (3) to calculate the CODcr removal rate, and the estimated value of CODcr removal rate and the influent CO
It is calculated by substituting Dcr into equation (5).

[0026] Treated water CODcr (mg/l) = inflow water C
ODcr (mg/l) - {CODcr removal rate (kg・
CODcr/m3/day) x aeration tank capacity (m3)/{inflow water amount x 10-3 (m3/1 day}...(5) Also, from the MLSS measurement value and inflow water CODcr, CO
Dcr volumetric load and CODcr/MLSS load are (6),
Calculated using equation (7).

[0027] CODcr volumetric load (kg・CODcr/
m3/day) = {Inflow water CODcr (mg/l) x Inflow water amount x 10-3 (m3/day)/Aeration tank volume (m3)...(6
) CODcr/MLSS load (kg/CODcr/kg
・MLSS・day)={Inflow water CODcr (mg/l)×
Inflow water amount (m3/day)}/{Aeration tank MLSS (mg/l
)×Aeration tank volume×10-3 (m3)}...(7) As described above, the CODcr/ATP load is first calculated in the first measurement data calculation section 3a from the ORP measurement value. Next, ATP is calculated from the CODcr/ATP load and ATU-Rr value in the second measurement data calculation section 3b, and the inflow water amount, MLSS value, ATP value and ATP
Based on the estimation result, the third measurement data calculation unit 3c calculates CO
Dcr volumetric load, CODcr/MLSS load, inflow water C
ODcr and treated water CODcr are calculated and estimated by the third estimation processing section 4c.

[0028] There is no need to measure the ATP concentration in the aeration tank, and the F/M ratio, inflow water CODcr, and treated water CODcr can be measured over a relatively wide temperature range using existing online automatic measuring devices called ORP meter and ATU-Rr meter. It can be estimated within It also has the advantage of being able to respond relatively quickly to changes in the amount of inflow water within a short period of time. Furthermore, there are clear advantages in that running costs such as reagent prices are low and complicated manual analysis operations in ATP measurement are omitted. Furthermore, it has the feature that it is possible to estimate the CODcr of treated water in addition to estimating the F/M ratio. Also BOD and COD
By using the correlation, BOD volume load, BOD・ML
It is also possible to estimate SS load, inflow water BOD, and treated water BOD.

[0029]

Effects of the Invention The present invention is as described above, and the flow rate value of the inflow water flowing into the aeration tank, the ATU-Rr in the aeration tank,
Since the F/M ratio is estimated by performing arithmetic processing based on the value and the ORP value, high-performance activated sludge treatment can be performed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram for implementing an activated sludge treatment control method according to an embodiment of the present invention.

FIG. 2 is an explanatory block diagram of the activated sludge treatment method shown in FIG. 1.

[Explanation of symbols]

1...Aeration tank 2...Sedimentation pond 3...Arithmetic device 3a...first measurement data calculation section 3b...Second measurement data calculation section 3c...Third measurement data calculation section 4... Estimation processing section 4a...first estimator 4b...Second estimator 4c...Third estimation part

Claims (1)

[Claims] [Claim 1] O which is the oxidation-reduction potential in the aeration tank
The CODcr/ATP load is estimated by calculating based on the RP value, and the CODcr/ATP load is calculated based on this CODcr/ATP load estimate and the ATU-Rr value, which is the allylthiourea respiration rate in the aeration tank. In addition to estimating the value of ATP, which is the ATP value, the value of ATU-Rr, which is the allylthiourea respiration rate in the aeration tank, the amount of inflow water flowing into the aeration tank, and the MLSS, which is the activated sludge concentration. Calculate the CODcr volumetric load, C based on the value.
An activated sludge treatment control method characterized by estimating the ODcr/MLSS load, the inflow water CODcr and the treated water CODcr, which are oxygen consumption amounts due to potassium dichromate oxide in the inflow water.