JPH11698A - Sludge concentration treatment method - Google Patents

Abstract

(57) [Summary] PROBLEM TO BE SOLVED: Applicable to small-scale equipment, easy operation management and stable concentration performance are obtained, and sludge concentration that does not adversely affect water treatment performance. Provide a processing method. SOLUTION: In a sewage treatment facility for subjecting wastewater such as sewage to biological treatment using activated sludge in an aeration tank 2 and concentrating and reducing excess sludge D, excess waste is directly discharged from the aeration tank 2 during the operation time of the aerator 7. Pull out the sludge D and guide it to the mechanical concentrator
It is characterized in that the operation time of the sludge concentrating device 5 is set and operated according to the integrated amount of treated water per day to the water treatment facility.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sludge concentration treatment which can be widely used as a pretreatment means for excess sludge generated in a sewage treatment facility for biologically treating sewage or other sewage with activated sludge. It is about the method.

[0002]

2. Description of the Related Art Conventionally, gravity type thickening tanks have been widely used for pretreatment of sludge in a sewage treatment facility using activated sludge such as a standard method or an oxidation ditch method.

[0003]

In the above-mentioned conventional method for concentrating sludge, the sludge condensing property is deteriorated due to a change in the properties of the generated sludge due to the separation of sewer pipes and changes in eating habits. The problem is that the smaller the equipment, the smaller the throughput, but the pipes cannot be made very thin due to the blockage of the pump, etc. There was a point. The present invention solves the above-mentioned problems of the conventional sludge concentration treatment method, can be applied to small-scale facilities, and can achieve stable concentration performance with easy operation management and water treatment performance. It is an object of the present invention to provide a sludge concentration treatment method which does not adversely affect the sludge.

[0004]

Means for Solving the Problems To achieve the above object, the method for concentrating sludge of the present invention uses an aerator to stabilize the concentration of sludge supplied to a concentrating apparatus and secure stable concentrating performance. During operation and during the time when the inside of the tank is sufficiently agitated and mixed, it is withdrawn from the aeration tank by a quantitative pump, and mechanical concentration is performed. Since the flow rate is proportional, a flow meter for measuring the amount of inflow water is provided, and the concentrator is operated for a time proportional to the integrated treated water amount per day calculated from the measured value of the flow meter.

In the sludge concentration treatment method of the present invention having the above-mentioned structure, the concentration of the sludge mixture (MLSS) in the aeration tank is stabilized because excess sludge is concentrated in accordance with the amount of generated sludge. As a result, the daily fluctuation of the concentration of sludge supplied to the concentrator becomes small, so that the water treatment performance and the concentration treatment performance are stabilized regardless of the load fluctuation from the start of operation to the time when the planned inflow water amount is reached.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the sludge concentration treatment method of the present invention will be described below with reference to the drawings. FIG. 1 shows a processing flow of a sewage treatment facility to which the present invention is applied. In the figure, reference numeral 1 denotes a pretreatment device, and 2 denotes an aeration tank connected to the pretreatment device 1 via an inflow pipe 8. Aeration tank 2
Is provided with a partition plate 21 in the central longitudinal direction in the shape of an oval to form a circulation channel 22 and one or more aerators 7 are disposed in the circulation channel 22.

Reference numeral 3 denotes a sedimentation tank, which is connected to the aeration tank 2 via an outflow pipe 9 and also has a sludge pipe 13 returned from the sedimentation tank 3 to the aeration tank 2. Reference numeral 4 denotes a disinfecting tank arranged to guide supernatant water flowing out of the sedimentation tank 3.
A flow meter 11 is provided at the subsequent stage, and the flow meter 11
The control unit 10 is electrically connected to the control unit 10, and the detection value of the water meter 11 is applied to the control unit 10 to control the sludge concentrator 5.
Since the amount of sludge generated in the small-scale treatment equipment is almost proportional to the amount of inflow water, a flow meter for measuring the amount of inflow water is separately provided, and is proportional to the integrated amount of inflow water per day calculated from the measured value of the flow meter. The control is performed so that the sludge concentration device 5 is operated only for a certain time.

The sludge concentration apparatus 5 is provided with a sludge pipe 14 so as to supply surplus sludge from the aeration tank 2 via a pump 12. To keep the concentration of sludge supplied to the sludge concentrator 5 constant and secure stable dehydration performance, excess sludge is directly drawn from the aeration tank, and a sludge storage tank 6 is connected to the sludge concentrator 5.

Accordingly, the organic wastewater sludge A such as sewage flows into the aeration tank 2 through the pretreatment device 1. In this embodiment, the aeration tank 2 shows an oxidation ditch provided with the screw type aerator 7, but the shape of the aeration tank and the aeration apparatus are not particularly limited. The sludge mixture in the aeration tank 2 overflows, flows into the sedimentation tank 3 and the sludge settles, and then returns to the aeration tank as returned sludge C. The supernatant water overflows and is sterilized in the disinfection tank 4. After that, it is discharged out of the system as discharge water B.

The flow meter 11 is provided at the subsequent stage of the disinfecting tank 4 and measures the discharge flow rate of the disinfecting tank. However, depending on the type and conditions of the flow meter, an inflow pipe, an inflow portion to the disinfecting tank, etc.
It is also possible to provide it at another position.

The excess sludge D is drawn directly from the aeration tank,
The mud is fed to the mechanical sludge concentrator 5 by the mud feed pump 12. In addition, the mud feed pump 12 is not limited to the tank outer shape as shown in the figure, and may be a submersible pump. However, it is necessary to use a pump having a small capacity and good flow rate stability.

A control device 10 for giving an operation instruction of the dehydrator has a function of acquiring measurement data of the flow meter 11 and an arithmetic function. The mud feed pump 12 is usually controlled by a dedicated control panel incorporated in the concentrating device 5, but it is also possible to incorporate all the functions of this dedicated control panel into the control device 10 and eliminate the dedicated panel attached to the concentrating device. It is possible. The treated concentrated sludge E is temporarily stored in the sludge storage tank 6 for a predetermined period, and then carried out of the site.

Next, the operation of the present invention will be described. For small-scale sewage, especially sewage, it takes at least one year for the inflow to reach the planned value. To maintain stable treatment performance, change the operation time as appropriate according to the inflow. It is necessary to go. In the present invention, the amount of water changing over time is measured by the flow meter 11 and input to the control device 10. In the arithmetic unit provided in the control device, the total of the daily flow rates is integrated, and a ratio r (= q / Q) of the integrated flow amount q and the planned inflow water amount Q is obtained. Next, this r
, The operating time of the concentrator per day is calculated. Note that the concentration conditions are determined in advance and set so that the processing amount per unit time is constant.

Next, assuming that the required operation time of the concentrator at the planned inflow water amount is T based on the concentration of the inflow water and the operating conditions of the water treatment, the operation time t of the concentrator at the integrated flow rate q is t.
Becomes t = r · T. However, actually, since q gradually increases while having a certain range of variation, it is not necessary to change the setting of t for q that changes daily, so that it is about one week to one month. It is preferable to obtain the average value of q in the period, and to change the setting of t in the next period based on this value.

The time of the timer can be set by manually calculating the above calculation based on the value of the flow meter having the integrating function, or by calculating t by an arithmetic unit in the control device, and then manually setting the timer. Good, but more desirably a device that can automatically change the timer built into the control device.

The type of the sludge concentrator is not particularly limited, but it can be operated automatically as long as at least a signal for starting and stopping the operation is given, and is stable even in a small-scale low-concentration sludge mixture (MISS). It is necessary to use a device that can provide processing performance. Further, since it is necessary to supply a surplus sludge having a stable concentration in order to obtain a stable concentration performance, it is performed during a time period when the aeration tank is sufficiently stirred and mixed by the aerator. Therefore, in the equipment that intermittently operates the aerator, the operation time T of the sludge concentrator at the time of the planned inflow water amount is compared with the aeration time per cycle. It is necessary to divide the operation so that all operations are performed during the aeration period.

[0017]

According to the sludge concentration treatment method of the present invention,
Excess sludge is withdrawn from the aeration tank where the sludge concentration is stable, the inflow is measured, and the enrichment treatment is performed for a time proportional to the amount of water.Thus, the sludge corresponding to the amount of generated sludge is extracted as surplus sludge, and stable. Since the concentration performance can be maintained and the MLSS concentration in the aeration tank is stabilized,
Even during the period from the start of operation to the planned inflow water amount, stable water treatment performance can be obtained regardless of load fluctuation.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a first embodiment of a sludge concentration treatment method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pre-processing apparatus 2 Aeration tank 22 Circulation channel 3 Sedimentation tank 4 Disinfection tank 5 Sludge concentrator 6 Sludge storage tank 7 Aerator 8 Inflow pipe 9 Outflow pipe 10 Controller 11 Flow meter 12 Sludge pump 13 Return sludge pipe 14 Pipe A Organic wastewater sludge B Discharge water C Return sludge D Excess sludge E Condensed sludge

Claims (1)

[Claims] Claims: 1. In a sewage treatment facility for subjecting wastewater such as sewage to biological treatment with activated sludge in an aeration tank and concentrating and reducing excess sludge, the excess sludge is drawn directly from the aeration tank during the operation time of the aerator. Characterized in that the sludge concentrator is operated by setting the operation time of the sludge concentrator according to the integrated amount of treated water per day to the water treatment facility.