JP2000167580A - Operation control of effluent type waste water treatment plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the quality deterioration of treated water by providing a flowmeter only to the water channel of the treated water discharged from a purifying treatment apparatus to detect the discharge amt. of the treated water by the flowmeter and detecting the abnormal inflow of raw water on the basis of the supply amt. of raw water to the purifying treatment apparatus to take correspondence. SOLUTION: In an operation control method of an effluent type waste water treatment plant wherein the raw water flowing in a raw water pit 1 is supplied to a purifying treatment apparatus 5 through pumps P1, P1' to be subjected to purifying treatment and treated water is discharged from the purifying treatment apparatus, an outlet flowmeter 12 detecting the discharge amt. of the discharged treated water to output a detection value and an operator 9 receiving the output of the outlet flowmeter to totalize the discharge amt. of the treated water and inputting the operation time of the pumps P1, P1' supplying the raw water flowing in the raw water pit to the purifying treatment apparatus are provided, and the supply amt. of the raw water supplied to the purifying treatment apparatus is operated on the basis of the discharge amt. of the discharged treated water and the operation time of the pumps P1, P1' by an operator to be calculated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a process for purifying raw water (sewage) flowing into a raw water pit from a sewage pipe by supplying the raw water (sewage) to a purifying apparatus by pumps P ₁ and P ₁ ′ in the raw water pit.
Drainage type wastewater treatment plant that discharges and discharges treated water from the purification treatment device to the amount of raw water supplied to the purification treatment device, typically the activated sludge method or the oxidation ditch method (OD method). Operation of the wastewater treatment plant
An outlet-side flow meter for detecting the discharge flow rate of the treated water to be discharged, and a pump P ₁ for supplying raw water from the raw water pit to the purification treatment device,
The present invention relates to a method for controlling the operation of a run-down type wastewater treatment plant controlled by P ₁ ′.

[0002]

2. Description of the Related Art FIG. 2 shows a population of about 700 to 800, 200
This is a general flow sheet of a wastewater treatment plant by the activated sludge method for settlement wastewater treatment in a village or the like where biological wastewater of about a house is biologically purified. aquarium, or raw water that has flowed into the final manhole provided in the sewer pipe (collectively the raw water tank and the final manhole referred to as raw water pit 1.) the conventional pump P ₁ one in raw water pit, one It is pumped into the flow control tank 2 by the preliminary pump P ₁ ′. Raw water is pumped from the flow control tank to the measuring tank 4 by the pumps P ₂ and P ₂ ′ in the tank, and from the measuring tank, the processing tank 5 of the purification treatment device (in this case, an aeration tank using a blower B).
The wastewater is measured and supplied, and the biological sludge and biological film are used for biological treatment in a treatment tank to purify the wastewater. The water treated in the treatment tank is introduced into the sedimentation tank 6 of the purification treatment apparatus in a falling manner to the supply amount of raw water supplied from the measuring tank to the treatment tank, and is separated into supernatant water and sludge, and the supernatant water is sterilized. It is introduced into the tank 7 for disinfection and treated water. Before the supernatant water flows into the sterilization tank, the COD is measured by a COD measuring instrument 10 such as a COD meter or a UV meter.
D is measured. Next, the disinfected treated water is introduced into the discharge tank 8 from the sterilization tank, and is pumped and discharged by the pumps P ₃ and P ₃ ′. A part of the sludge generated in the settling tank is returned to the processing tank.

[0003] As shown in FIG.
The capacity between -L is 10 to 1 of the maximum inflow (Qmax) over time.
About 5 minutes (about 45 minutes of daily average inflow Q), Q = 2
40m ³ / day, Qmax = 28.9m ³ / sometimes 4.
In 8m ³ ~7.2m ^3, here, the 5.0m ^3. On the other hand, the capacity between the water level HL of the flow control tank 2 is 6 hours or more of the daily average inflow, generally 6 to 9 hours, and Q = 24.
0 m ³ / day, here, 60 m ³ as 6 hours. The raw water pit, the discharge amount of the inflow wastewater can short time pumping the gel, accurate and regular capable pumping the gel maximum inflow (Qmax) time, a water pump P ₁ of the two pre-P ₁ 'is provided. The flow control tank 2 is provided with two regular pumps or one regular pump and one spare submersible pump P ₂ , P ₂ ′. The discharge amount of the service pump P ₂ and the preliminary pump P ₂ ′ of the flow rate adjusting tank 2 is greater than the daily average amount of sewage because a small amount of raw water is supplied to the processing tank via the measuring tank and the load on the processing tank is not rapidly increased. In general, in the case of settlement drainage treatment, when there are two service pumps, the discharge amount of one service pump P ₂ is the service pump P of the raw water pit.
₁ 1/6, when conventional pumps of one its discharge amount is 1/3 of the conventional pump of the raw water pit.

As shown in FIG. 3, two or one regular pump P ₂ of the above-mentioned flow rate adjusting tank and a spare pump P ₂ ′
Is usually controlled by the level switch LS2 provided in the tank, conventional pump P ₂ starts operating and the water level becomes M of 1 m, and stops when the water level drops to L of 0 m, the preliminary pump P
₂ 'starts operation when the water level rises to 3.5m HH, and stops when the water level falls to 3m H. The service pump P ₁ and the backup pump P ₁ ′ of the raw water pit are also controlled by the level switch LS 1 provided in the pit, and the service pump P ₁ starts operating when the water level reaches 2.0 m H, and the L level when the water level is 0 m. It stops when it goes down. Raw water pit small volume as mentioned above, and since the discharge amount of the pump is large, conventional pump P ₁ is frequently repeats ON, means OFF. The preliminary pump P ₁ ′ of the raw water pit starts operating when the water level rises to 2.5 mHH, and stops when the water level falls to 2.0 mH.
ANN in which each level switch LS1, LS2 issues an alarm
The water level is 4.5 m in the flow control tank and 3.0 m in the raw water pit.

According to Japanese Patent Application No. 7-70476 (Japanese Unexamined Patent Application Publication No. 8-243439), the applicant of the present invention has shown a flow control tank 2 from raw water pit 1 using pumps P ₁ and P ₁ ′ as shown in FIG. An electromagnetic-type inlet-side flow indicator integrating recorder 11 (also referred to as an inlet-side flow meter) is provided in a pipe for pumping raw water, and a COD meter is provided in a channel for guiding supernatant water from the sedimentation tank 6 to the sterilization tank 7.
A COD measuring device 10 such as a UV meter, and an electromagnetic outlet-side flow-indicating integrating recorder (outlet-side flow meter) are connected to a pipe that is pumped by pumps P ₃ and P ₃ ′ to discharge treated water from the discharge tank 8. ), And the raw water supplied from the raw water pit 1 output from the inlet flow meter 11 to the flow control tank 2, for example, the water supply amount every 10 minutes, the daily water supply amount, and the outlet flow amount. Hourly discharge of treated water output by the total 12;
And the total discharge amount for one day, 1 output by the COD measuring device 10
Control COD value (mg / litre) of treated water for each time
It has been disclosed that an arithmetic unit 9 such as a personal computer or a sequencer that receives the data via the computer is provided.

The calculator 9 calculates the total amount of COD discharged per day (kgCOD / day) from the input of the outlet flow meter 12 and the input of the COD measuring device 10, and stores, records and records it. It became possible to do. CO of treated water
Reason for determining the daily total emissions of D is, by region, treated water day 50 m ³ or more, in facilities such as factories discharged, tolerance emissions per day COD per facility is defined, Because it is required to prove that COD emissions per day are below the allowable value,
COD ≒ BOD × 1.6 to 2.0, and BOD can be estimated by calculation, whereas COD cannot be measured continuously.
In addition, since it cannot be obtained without manual analysis,
To estimate COD by BOD instead of OD and check the processing status, and adjust the amount of air for aeration and the amount of returned sludge according to the value of COD to maintain a good and normal operating condition. And so on.

Also, raw water (sewage) flowing into the raw water pit 1
The average daily inflow (Q) is about 24
At 0 m ³ , as shown by the solid line in FIG. 4, the inflow is almost 0 from midnight to early 5 am, and the peak of inflow is 10 am from 7 am
Until the hour and twice from 6:00 to 8:00 in the evening, there is a small peak after lunch in the valley of the morning and evening peaks in the daytime, but it flows in at other times. This normal inflow pattern is repeated every day unless water increases due to abnormal weather such as torrential rain.

Therefore, the arithmetic unit 9 normally has an inflow pattern.
Of raw water from raw water pit 1 to flow control tank 2
The supply amount for every 10 minutes of time is stored, and the arithmetic unit is
The actual supply amount input by the inlet flowmeter 11 and the
Calculate the memory supply amount at the same time, and store the actual water supply amount.
When the supply amount exceeds a predetermined amount for a predetermined time (for example, 30 minutes),
The calculator calculates the amount of raw water supplied from the raw water pit to the flow control tank.
It becomes a monitoring system to monitor the increase and decrease, and the actual supply amount is stored and stored.
The amount is further increased by a predetermined amount for a predetermined time (for example, 2 hours)
The arithmetic unit determines that water will increase, and
Tomo service pump P _TwoTo the tank water level (level switch LS2
 ) Regardless of the operation, the raw water in the flow control tank is transferred to the treatment tank.
Pump the water and flow forward before the rising water flows into the raw water pit.
Lower the water level in the volume adjustment tank, and the increased water flows from the raw water pit
Enter the flow control tank beyond the adjustment capacity of the flow control tank and process
The treated water whose quality has deteriorated has overflowed from the treatment tank
Or the water level in the flow control tank reaches the ANN level and an alarm is issued.
To avoid being overwhelmed by the response.

The inlet flow meter also outputs the actual supply amount to the computing unit when flowing in the normal inflow pattern. However, since the computing unit has a small difference from the stored supply amount at that time, the pump P ₂ , P ₂ ′ are not controlled. Therefore, during the normal inflow pattern, the operation of the pumps P ₁ and P ₁ ′ is controlled by the limit switch LS1 of the raw water pit, and the operation of the pumps P ₂ and P ₂ ′ is controlled by the limit switch LS2 of the flow control tank.

[0010]

In the above-mentioned conventional apparatus, a COD measuring device 10 and a flow-rate indication integrating recorder 12 are installed at the outlet side in order to know the COD load of the treated water to be discharged. Install the inlet-side flow-indicating integrated recorder 11 to know the supply amount of raw water that flows into the plant and supplied to the purification treatment device, and to prevent the deterioration of the quality of treated water that is discharged in the event of abnormally high water levels such as concentrated torrential rain. However, since the flow rate indicating and integrating recorder is an extremely expensive device, the installation of two units causes an increase in the installation cost of the runoff type wastewater treatment plant.

Further, the flow meter on the inlet side is always in contact with the dirty raw water, so that the dirt adheres, and the adhered dirt feeds the raw water from the raw water pit to the flow rate regulating tank, and eventually to the drainage type wastewater treatment plant. There is a possibility that the amount of inflowing raw water may not be correctly output to the control panel 3 and the computing unit 9, whereby the control panel and the computing unit determine that the abnormal inflow has occurred even though the raw water flows normally as usual. In other words, there is a possibility that the monitoring system may be grasped, or conversely, it may be determined that the inflow has occurred as usual even though the abnormal inflow has occurred, and the monitoring system may not be grasped.

[0012]

SUMMARY OF THE INVENTION The present invention has been developed in order to solve the above-mentioned problems, and the raw water flowing into the raw water pit from the sewer pipe is supplied to the raw water pit pump P ₁ ,
Through a P ₁ ′, the water is supplied to the purification treatment device for purification treatment, and the water treated by the purification treatment device is drained, discharged, and discharged to the supply amount of the raw water supplied to the purification treatment device. In the operation control method, an outlet flowmeter that detects and outputs a discharge flow rate of the treated water discharged, and collects the discharge flow rate of the treated water discharged and received by the output of the outlet flowmeter, and stores the raw water pit in the raw water pit. A computing unit is provided for inputting the operation time of the pumps P ₁ and P ₁ ′ for supplying the inflowing raw water to the purification treatment device, and the operation time of the pumps P ₁ and P ₁ ′ is determined by the discharge flow rate of the discharged treated water and the operation time of the pumps P ₁ and P ₁ ′. The supply amount of raw water to be supplied to the purification treatment device is calculated by the computing unit.

[0013]

FIG. 1 shows an embodiment of the present invention, in which the same elements as those of the prior art shown in FIG. 2 are denoted by the same reference numerals. In the present invention, the flow rate indicator integrating recorder (flow meter) 12 is provided only on the outlet side for discharging treated water. In FIG. 1A, as in FIG.
Is released the pump P ₃ which operates from discharge tank 8 by the limit switch LS3, it is provided in 'discharge path 8 for discharge by pumping the treated water by' P _3, but sterile tank as shown in FIG. 1 (B) If the treated water disinfected from 7 can be discharged under the natural flow through the discharge tank 8, the discharge pumps P ₃ and P ₃ ′ are omitted, and the discharge pipe 7 ′ for discharging the treated water from the sterilization tank 7 to the discharge tank 8.
The outlet-side flow meter 12 may be attached inside of the device to make it a diving type.

The outlet side flow meter 12 inputs the flow rate of the treated water to the arithmetic unit 9 via the control panel 3 in the same manner as in the conventional example of FIG.
Therefore, when knowing the COD load of the treated water, the COD load of the supernatant water before sterilization from the sedimentation tank 6 as in the conventional example of FIG.
Is measured with a COD measuring instrument 10 such as a COD meter and a UV meter,
The output is input to a computing device 9 such as a personal computer or a sequencer via the control panel 3, and the computing device 9 calculates the value of the treated water 1 from the integration of the input and the discharged flow rate of the treated water input from the outlet flow meter 12. Calculate and store total COD emissions per day,
Can be recorded.

Water level HL of raw water pit 1 and flow control tank 2
The inter-volume is as shown in the aforementioned paragraph 0003, and the operation of the service pump P ₁ and the spare pump P ₁ ′ of the raw water pit and the service pump P ₂ and the spare pump P ₂ ′ of the flow rate adjusting tank are performed in the respective pits 1 and 2. The control is performed by the level switches LS1 and LS2 provided in the tank 2 as described in paragraph 0004. In addition, regular use of the raw water pit 1 and preliminary pumps P ₁ , P
₁ ′, the normal use of the flow control tank 2 and the preliminary pumps P ₂ , P
₂ 'is connected to the control panel 3 to input the operation status to the computing unit. The level switches LS1 and LS2 of the raw water pit and the flow control tank are also connected to the control panel 3, and the pit 1 and the tank 2 Water level (level switch L, M, H, HH, AN
(Positions such as N) are also input to the arithmetic unit 9.

In the present invention, the raw water pit 1 is normally used and is
Pump P₁, P₁′ Controls the operation status (operating time)
3 and input to the arithmetic unit 9. Because of this, the pump
P₁, P ₁′, Connect an operating hour meter to each
The data may be input to a computing unit via a control panel using a running hour meter. or,
The outlet flow meter 12 controls the instantaneous discharge flow rate of the treated water discharged.
The data is input to the arithmetic unit 9 via the control panel 3. Arithmetic unit is on the outlet side
Receiving the input of the meter 12, processing every hour for 24 hours a day
Calculate the discharge rate of water and calculate the total discharge rate Qe of treated water per day
m^ThreeCalculate / day. Qe = q¹+ Q^Two＋ ・ ・ ・ ・ ・ ・ ＋ q^{twenty four}・ ・ ・ ・ ・ ・ ・ (1) q¹: 1 hour discharge of treated water from 0:00 to 1:00
[M^Three/ Hour] q^Two： Discharge of treated water for 1 hour from 1:00 to 2:00
[M^Three/ Hour] ∫ q^{twenty four}: Discharge of treated water for 1 hour from 23:00 to 24:00
Flow rate [m^Three/time〕

The computing unit calculates the daily operating time of each of the pumps P ₁ , P ₁ ′ based on the inputs of the ordinary and spare submersible pumps P ₁ , P ₁ ′ of the raw water pit 1. TP ₁ = t ₁ P ₁ + t ₂ P ₁ +... + T ₂₄ P ₁ ... (2) TP ₁ : Operating time per day of the service pump P ₁ [hour /
Day] t ₁ P ₁ : One-hour operation time of pump P ₁ from 0:00 to 1:00 t ₂ P ₁ : One-hour operation time of pump P ₁ from 1:00 to 2:00 ｔ t ₂₄ P ₁ : ₁ from 23:00 to 24:00 of pump P 1
Time operating time TP ₁ ′ = t ₁ P ₁ ′ + t ₂ P ₁ ′ +... + T ₂₄ P ₁ ′... (3) TP ₁ ′: Preparatory pump P ₁ ′ Operating time per day [hour / day] t ₁ P ₁ ′: ₁ from 0:00 to 1:00 of pump P ₁ ′
Operating time t ₂ P ₁ ′: ₁ from 1: 00 to 2:00 of the pump P ₁ ′
Hours operating time ∫t ₂₄ P ₁ ′: _One hour operating time of pump P ₁ ′ from 23:00 to 24:00

When raw water flows in the normal flow pattern shown by the solid line in FIG.
Since the treated water is dripped and discharged from the purification treatment device, the discharged water Qem ³ / day per day coincides with the inflow Qim ³ / day of raw water per day. Qi = Qe ········· (4) per day of pumping of conventional pump P ₁ of raw water pit QP
₁ , the pumping amount per day of the spare pump P ₁ ′ is Q
Assuming that P ₁ ′, Qi = QP ₁ + QP ₁ ′ (5) QP ₁ = TP ₁ · Q _AV P ₁ (6) QP ₁ ′ = TP ₁ '· Q _AV P ₁ ' (7) QP ₁ : Pumping amount of pump P ₁ per day [m ³ / day] Q _AV P ₁ : Average pumping amount of pump P ₁ per hour [M ³
/ Hour] QP ₁ ′: Pumping amount of pump P ₁ per day [m ³ / day] Q _AV P ₁ ′: Average pumping amount of pump P ₁ ′ per hour [m ³ / hour]

From the above equations (4), (5), (6) and (7)
Qe = Qi = QP₁+ QP₁'= TP₁・ Q_AVP₁+ TP₁'・ Q_AVP₁'... (8) Here, the common pump P is generally used.₁And backup pump P₁′ Is the same
Use the same model from one manufacturer under the same conditions. Therefore Q_AVP₁= Q_AVP₁'... (9) Then, Qe = (TP₁+ TP₁') ・ Q_AVP₁ Q_AVP₁= (Qe) / (TP₁+ TP₁') (= Q_AVP
₁') ・ ・ ・ ・ (10) and the regular pump P for raw water pit 1
₁And the spare pump P₁′_AVP₁, Q _AVP₁′
And the discharge amount Qe of the treated water input by the outlet side flow meter 12;
Pump P₁, P ₁′ Can be obtained from the operating time
You.

The above items will be specifically described. Regular pump P in raw water pit in case of normal inflow pattern (solid line) in FIG.
The movement of ₁ is shown in FIG. Here, the discharge rate per pump for the regular and spare pumps in the raw water pit is 50 m ³ / hour (H)
And the amount of water retained between the water levels H and L in the raw water pit is described in paragraph 0.
5m ³ as shown in FIG. From 5:00 to 6:00, regular pump P for raw water pit with 50 m ³ / H capacity
₁ operated 6 minutes x 2 times = 12 minutes. Pumping volume is 50m ³
/ H × １ ／ H = 10 m ³ / hour. Similarly, from 7:00 to 8:00, 50 m ³ / H × 2 / 5H = 20 m ³
Becomes The process proceeds in the same manner.

The amount pumped conventional pump P ₁ of raw water pit in the normal inflow pattern by the above is as follows in each time period. ^{0: 00~ 1:00 0m 3 1:} 00~ 2:00 0m 3 2: 00~ 3:00 0m 3 3: 00~ 4:00 0m 3 4: 00~ 5:00 0m 3 5: 00~ 6 0:00 50 m ³ / H × (6/60 × 2 times) H = 10 m ³ 6: 0 to 7:00 50 m ³ / H × (6/60 × 2 times) H = 10 m ³ 7: 0 to 8:00 50 m ³ / H × (6/60 × 4 times) H = 20 m ³ 8:00 to 9:00 50 m ³ / H × (6/60 × 6 times) H = 30 m ³ 9:00 to 10:00 50 m ³ / H × (6/60 × 8 times) H = 40 m ³ 10:00 to 11:00 50 m ³ / H × (6/60 × 2 times) H = 10 m ³ 11:00 to 12:00 50 m ³ / H × (6/60 × 1 ^{time) H = 5m 3 12: 00~13} : 00 50m 3 / H × (6/60 × 1 ^{time) H = 5m 3 13: 00~14} : 00 50m 3 / H (6/60 × 2 ^{times) H = 10m 3 14: 00~15} : 00 50m 3 / H × (6/60 × 1 ^{time) H = 5m 3 15: 00~16} : 00 50m 3 / H × (6 / 60 × 1 ^{time) H = 5m 3 16: 00~17} : 00 50m 3 / H × (6/60 × 1 ^{time) H = 5m 3 17: 00~18} : 00 50m 3 / H × (6/60 × 1 time) H = 5 m ³ 18:00 to 19:00 50 m ³ / H × (6/60 × 4 times) H = 20 m ³ 19:00 to 20:00 50 m ³ / H × (6/60 × 6 Times) H = 30 m ³ 20:00 to 21:00 50 m ³ / H × (6/60 × 2 times) H = 10 m ³ 21:00 to 22:00 50 m ³ / H × (6/60 × 2 times) H = 10 m ³ 22:00 to 23:00 50 m ³ / H × (6/60 × 2 times) H = 10 m ³ 23:00 to 24:00 0 m ³ Thereby, from 0:00 to 2 The total pumping amount until 4:00 is 240 m ³ / day.

On the other hand, FIG. 6 shows the operation of the ordinary pump and the spare pump in the raw water pit when the abnormal inflow pattern (dot-dash line) is from 0 o'clock to 7 o'clock in FIG. 1:00 o'clock 0, pumping destined 2:00 respectively ^{50m 3 / H × 1 / 10H} = 5m 3 from 1:00, 3 o'clock 2 ^{50m 3 / H × 1 / 5H} = 1
0m ³ pumps. From 3 o'clock to 4 o'clock, FIG.
As shown in FIG. 6, after 6 minutes from 3:06 to 3:12, the operation is continuous for 42 minutes from 3:18 to 4:00.
The pumping amount during this period is 50 m ³ / H × (6 + 42) / 6
0H = 40 m ³ .

This is shown below from 0:00 to 24:00. 0:00 to 1:00 50 m ³ / H × (6/60 × 1 time) H = 5 m ³ 1: 00 to 2:00 50 m ³ / H × (6/60 × 1 time) H = 5 m ³ 2: 00 to 3:00 50 m ³ / H × (6/60 × 2 times) H = 10 m ³ 3: 0 to 3:30 50 m ³ / H × (6/60 × 3 times) H = 15 m ³ 3:30 to ^{4:00 50m 3 / H × (30} /60 × 1 ^{time) H = 25m 3 4: 00~} 5:00 50m 3 / H × (60/60 + 6/60 × 6 times) H = 80m ³ 5: 00~ ^{6:00 50m 3 / H × (60} /60 + 10/60 × 2 ^{times) H = 60m 3 6: 00~} 7:00 50m 3 / H × (6/60 × 8 times) H = 40m ³ 7: 00~ ^{8:00 50m 3 / H × (6} /60 × 4 ^{times) H = 20m 3 8: 00~} 9:00 50m 3 / H × (6/60 × 6 ^{times) H = 30m 3 9: 00~10} : 00 50m ³ / H × (6/60 × 8 times) H = 40m ³ 10:00 to 11:00 50m ³ / H × (6/60 × 2 times) H = 10m ³ 11:00 to 12:00 50m ³ / H × (6/60 × 1 time) H = 5 m ³ 12:00 to 13:00 50 m ³ / H × (6/60 × 1 time) H = 5 m ³ 13:00 to 14:00 50 m ³ / H × (6/60 × 2 times) H = 10 m ³ 14:00 to 15:00 50 m ³ / H × (6/60 × 1 time) H = 5 m ³ 15:00 to 16:00 50 m ³ / H × ( 6/60 × 1 time) H = 5 m ³ 16:00 to 17:00 50 m ³ / H × (6/60 × 1 time) H = 5 m ³ 17:00 to 18:00 50 m ³ / H × (6/60 60 × 1 ^{time) H = 5m 3 18: 00~19} : 00 50m 3 / H × (6/60 × 4 ^{times) H = 20m 3 19: 00~20} : 00 50m 3 / H × (6 / 0 × 6 ^{times) H = 30m 3 20: 00~21} : 00 50m 3 / H × (6/60 × 2 ^{times) H = 10m 3 21: 00~22} : 00 50m 3 / H × (6/60 × 2 times) H = 10 m ³ 22:00 to 23:00 50 m ³ / H × (6/60 × 2 times) H = 10 m ³ 23:00 to 24:00 0 m ^{3 With} this, from 0:00 to 24:00 Total pumping amount is 460 m ³ / day.

The change in the water level of the flow control tank and the amount of water supplied from the flow control tank to the processing tank with respect to the operation state of the pump in the raw water pit during the normal inflow pattern and the abnormal inflow pattern are shown in FIGS. , 9. FIG. 7 is an example corresponding to a general control method, and FIGS. 8 and 9 are examples corresponding to an abnormal inflow pattern. FIGS. 7, 8, and 9 illustrate the case where the number of pumps in the flow rate adjusting tank is one regular and one spare. When there are three pumps in the flow rate adjusting tank, two pumps are used regularly and one pump is used as a spare. Further, in order to extend the service life of the pump, the two regular pumps are often switched over for a fixed period, for example, every two weeks. Assuming that the three submersible pumps are A, B, and C, the switching method is as follows: A and B are used for 2 weeks, C is reserved during that time, B and C are used for the next 2 weeks, A is reserved,
For the next two weeks, C and A are in regular use and B is in reserve.
In the case of three pumps, the capacity of each pump is the same, so that the pumping amount of one spare pump during operation is の of that of two regular pumps. Here, the case of a simple regular one and a spare one will be specifically described. FIG.
When the water level reaches M, one of the service pumps in the flow control tank operates and stops at L. This is a completely common control method in which when the water level reaches HH, two regular and spare units are operated, and at H, one regular unit is used. In this case, as shown in FIG. 7, at 5:30, the ANN (alarm level) is reached, and the raw water overflows to the next processing tank by 6:00 until 6:00. Until 10:20, two pumps in the flow control tank are used as usual and spare, and from 10:20, one pump is used as normal. One regular vehicle stops at 14:53 and runs again from 18:12 to 23:00. During this time, the water supply amounts of the regular and spare pumps are as shown in the upper part of FIG. 7, and the pumping amount is 450 m ³ . The overflow from the flow control tank to the processing tank is 10 m ³ , which is 460 m ³ / day in total. This indicates that an abnormal inflow pattern cannot be accommodated before the normal inflow pattern, and that 10 m ³ of raw water overflows from the flow control tank into the treatment tank, deteriorating the quality of the treated water discharged.

On the other hand, pump P for raw water pit₁, P₁'of
Determining that abnormal inflow may occur depending on operating conditions
FIG. 8 and FIG. 9 show an example in which a corresponding action is taken. FIG.
Of 0:00 to 1:00 and 1:00 to 2:00 in FIG.
There was one operation of the service pump in each raw water pit
Judgment of the possibility of abnormalities in the event, abnormal in the next 2:30 operation
And the pump P of the flow control tank_TwoCommand start
You. In addition, regular pump P at 3:30₁From intermittent to continuous
When the pump becomes_Two′ To start
You. FIG. 9 shows the case of 0:00 to 1:00 and 1:00 to 2:00.
Regular pump P for raw water pit once each₁Driving
Judge that there may be an abnormal inflow in the next two:
It is judged that there is a possibility of abnormality in the operation from 00 to 3:00
After a predetermined time, for example, three hours,
Two pumps P for regular use and spare for volume adjustment tank_Two, P _TwoSame as ′
Sometimes command start.

As described above, correspondence 1 in FIG. 8 and correspondence 2 in FIG.
In both cases, unlike FIG. 7, the raw water can be supplied without overflowing from the flow control tank to the processing tank. As a result, as shown in FIG. 10, in the case of correspondences 1 and 2, the treated water satisfies the discharge reference value even if there is an abnormal inflow, but in the case of FIG. Water quality (BOD here) deteriorates rapidly. Once deteriorated, it does not return to the original water quality for half a day to 1.5 days.

Thus, the pumps P ₁ ,
It is determined whether or not there is an abnormal inflow according to the operation status of P ₁ ′, and when it is determined that there is an abnormal inflow, the computing unit controls the regular and spare submersible pumps P ₂ and P ₂ ′ of the flow regulating tank. The effect on the treated water is very different between the case where the pump is operated in conjunction with the water level (level switch) of the flow control tank without detecting whether there is an abnormal inflow or not at all. In the latter case, the quality of the treated water deteriorates.

It is a matter that must be observed when the water is discharged into the public water area to satisfy the discharge standard value of the area. However, as in the present invention, a flow meter is installed only on the discharge side, and the raw water is discharged. It is possible to know the amount of inflow based on the operating status of the pump in the pit and take measures in an abnormal inflow state. In addition, in the normal case, since the inflow water amount and the treated water amount are the same, it is assumed that the discharge amount of the raw water pump (= the treated water amount / the raw water pump operation time) is always checked, and the amount is corrected by a change with time. .

[0029] a conventional pump P ₁ of raw water pit as described in paragraph 0018, the preliminary pump P ₁ 'is using the same type of the same manufacturer under the same conditions, In addition, the pump P _1,
If there is a difference in performance in P ₁ ′, the pump coefficient is adjusted by giving it to equation (9). Also, the amount of treated water used for calculation,
And the operation time of the pumps P ₁ and P ₁ ′ is accumulated for a period of about one week (may be longer in some cases), and the average (operation average updated daily) is used. Is preferred.

[0030]

As is apparent from the above description, the amount of inflow of raw water into the purification treatment device in the conventional run-down type wastewater treatment device,
In order to know the flow rate of the treated water from the purification treatment device, a very expensive flow indicator integrating recorder is installed at each of the inlet and outlet of the purification treatment device and connected to the control panel. In the present invention, the discharge flow rate of the treated water can be known with one flow rate indicator integrated recorder installed at the exit side of the purification treatment apparatus, and the regular and spare water pits can be used. The amount of raw water flowing into the purification treatment device can be known from the operation status (the number of times of operation) of the submersible pump, and the quality of treated water can be prevented from deteriorating in response to an abnormal flow pattern. That is, if the number of times of operation of the pumps P ₁ and P ₁ ′ of the raw water pit is known, it is possible to easily determine whether the raw water normally flows or abnormally flows without performing sophisticated pattern recognition.
In addition, only one expensive flowmeter can be used, and installation cost and maintenance cost of the meter can be reduced to one. Furthermore, since this flow meter comes into contact with treated and purified treated water instead of dirty raw water, the flow meter is kept cleaner than when it comes into contact with raw water, and is less contaminated, so that it is easier to maintain and manage. Does not work. And it can respond quickly to the abnormal inflow of raw water. In other words, it is possible to quickly know the abnormal state and take measures to prevent the occurrence of an abnormal situation, and to take quick action to respond to the abnormal inflow automatically, thereby preventing deterioration of the quality of treated water.

[Brief description of the drawings]

FIG. 1 (A) is an explanatory view of an embodiment of an activated sludge run-down type wastewater treatment plant operated according to the present invention, and FIG. 1 (B) is another embodiment of a run-down type wastewater treatment plant operated according to the present invention. Explanatory drawing of the principal part of a form.

FIG. 2 is an explanatory view of a conventional activated sludge run-off type wastewater treatment plant.

FIG. 3 is a cross-sectional view of a part of a raw water pit, a flow tank, and a treatment tank of FIG. 1;

4A is a diagram showing a normal inflow pattern of raw water in a raw water pit for a day and an abnormal inflow pattern, and FIG. 4B is an enlarged view of a part of the abnormal inflow pattern of the same.

FIG. 5 is an explanatory diagram of an operation state of a pump of a raw water pit in the normal inflow pattern of FIG. 4;

FIG. 6 is an explanatory diagram in which the operation state of the pump of the raw water pit in the abnormal inflow pattern of FIG. 4 is superimposed on the operation state of the pump of the raw water pit in the normal inflow pattern of FIG.

FIG. 7 is an explanatory diagram of a supply state of raw water from a flow rate adjustment tank to a treatment tank in a normal inflow pattern and an abnormal inflow pattern in FIG. 4;

8A is a diagram showing an example of the supply amount of raw water from a flow rate adjustment tank to a treatment tank corresponding to the abnormal inflow pattern of FIG. 4 by the pumps P ₂ and P ₂ ′, and FIG. The figure which shows the fluctuation | variation of the water level in an adjustment tank (the number in a parenthesis represents a water level, and the number outside a parenthesis shows a water quantity).

9A is a diagram showing the supply amount of raw water from the flow rate adjustment tank to the treatment tank of another example corresponding to the abnormal inflow pattern of FIG. 4 by the pumps P ₂ and P ₂ ′, and FIG. Figure showing the fluctuation of the water level in the flow control tank in (The figures in parentheses indicate the water level,
The numbers outside the parentheses indicate the amount of water).

FIG. 10 is a diagram showing a change in the quality of treated water when the abnormal water flow pattern does not correspond to the abnormal inflow pattern.

[Explanation of symbols]

1 Raw water pit P ₁ Regular pump for raw water pit P ₁ ′ Reserve pump for raw water pit 2 Flow regulating tank P ₂ Regular pump for flow regulating tank P ₂ ′ Reserve pump for flow regulating tank 3 Control panel 4 Measuring tank 5 Purification treatment device ( Processing tank) 6 sedimentation tank 7 sterilization tank for disinfection 8 discharge tank 9 computing device (PC, sequencer) 10 COD measuring device (COD meter, UV meter, etc.) 12 flow meter at outlet side (electromagnetic flow indication integrated flow meter) 21 Sewer pipeline

Claims (1)

[Claims] 1. Raw water flowing into a raw water pit from a sewer pipe is supplied to a purification treatment device via pumps P ₁ , P ₁ ′ in the raw water pit for purification treatment, and the supply amount of raw water supplied to the purification treatment device In an operation control method of a run-down type wastewater treatment plant that discharges and discharges treated water from a purification treatment device, an outlet-side flow meter that detects and outputs a discharge amount of treated water that is released, and the outlet-side flow meter The pumps P ₁ and P ₂ supply the raw water that has flowed into the raw water pit to the purification treatment device, while summing up the discharge flow of the treated water that has been discharged in response to the output of
An arithmetic unit for inputting the operation time of P ₁ ′ is provided, and the supply amount of the raw water to be supplied to the purification processing device is determined by the discharge flow rate of the discharged treated water and the operation time of the pumps P ₁ and P ₁ ′. An operation control method for a run-down type wastewater treatment plant, wherein the operation control method is obtained by calculating in (1).