KR20110068727A - Tornado style automatic aeration method and device in sub-merged membrane system - Google Patents

Abstract

PURPOSE: An automatic air cleaning method of a submerged separation membrane filtration apparatus, and the submerged separation membrane filtration apparatus are provided to reduce the generation of the uneven membrane pollution during a separation membrane filtration process. CONSTITUTION: An automatic air cleaning method of a submerged separation membrane filtration apparatus comprises the following steps: calculating the flux J value using the temperature, the transmembrane pressure, and the filtering flux value during a membrane filtration process; calculating data for forming a graph of the filter membrane resistance value R using the flux J value; obtaining the filter membrane resistance value Rn for operating an air cleaning process of a separation membrane, by discharging air through a nozzle of a diffuser; and stopping the air cleaning process and returning to the membrane filtration process.

Description

Automatic Air Cleaning Method of Submerged Membrane Filtration and Submerged Membrane System with Tornado Automatic Air Cleaning Function {Tornado Style Automatic Aeration Method and Device in Sub-merged Membrane System}

The present invention relates to a water treatment technology using filtration of a membrane, and specifically, in a filtration apparatus using an immersion type membrane, the membrane contamination of the membrane is measured and timely air membrane removal is performed to remove membrane contamination. The air cleaning is carried out in a tornado manner, but the air injection is concentrated on both edges of the membrane module where membrane contamination is concentrated, thereby improving the efficiency of membrane cleaning and reducing energy consumption. The present invention relates to an air cleaning method of a membrane filtration device and an immersion type membrane filtration device having a tornado air cleaning function.

As the air cleaning method for the conventional immersion membrane in the water treatment apparatus, the Cyclic Aeration method and the Automatic Aeration Filtration (AAF) method are known. These conventional methods are all developed as a method for minimizing membrane contamination and increasing energy efficiency. However, in the case of the Cyclic Aeration method, there is a disadvantage in that the water quality fluctuations are not efficient for raw water conditions. On the other hand, the AAF method is a technology for changing the aeration method by membrane inflow turbidity and membrane contamination index and controlling the aeration intensity.It can respond to changes in raw water quality and can be linked with automatic control, Has a disadvantage that the optimal aeration intensity formula for the membrane fouling index must be derived again.

The present invention was developed to overcome the problems and limitations of the conventional immersion membrane cleaning method as described above, by considering the membrane fouling characteristics for the horizontal immersion membrane, so that the membrane can be cleaned more efficiently and economically It is the ultimate goal.

Specifically, regardless of seasonal changes in raw water quality, the purpose is to grasp the membrane fouling level of the membrane and to clean the membrane by air cleaning as needed, and to perform intensive cleaning on the part where membrane fouling occurs largely. It is done.

In the present invention, in order to achieve the above object, in the immersion type membrane filtration device, the membrane filtration resistance value (Membrane) of the membrane by measuring the transmembrane pressure, the filtered water temperature, the membrane flux (Flux), etc. in real time Resistance), and when the calculated membrane filtration resistance is increased above a predetermined set value, the air cleaning of the separator is necessary, and thus the method of automatically cleaning the air and the automatic cleaning function of the separator by such a method are performed. An immersion type membrane filtration device having a is provided.

In addition, in the present invention, the cleaning of the separation membrane by the injection of air, the air cleaning of the immersion membrane filter apparatus that effectively reduces the cake layer formed on the surface of the separation membrane by injecting air to the portion where the membrane contamination is concentrated in a tornado method A method and an immersion separator filtration apparatus with tornado air cleaning are provided.

According to the present invention, in the immersion type membrane filtration apparatus, it is possible to overcome the occurrence of heterogeneous membrane contamination generated in the membrane filtration process by concentrating the air cleaning amount to the portion where the membrane fouling degree of the membrane is severely generated.

In addition, by using the physical quantity measured in real time by the measuring device to determine the degree of membrane contamination in real time and automatically control the cleaning time of the membrane based on this, it is possible to maintain the filtration performance of the membrane in the best state, This enables safe and reliable water treatment.

In particular, by configuring the measuring device to enable on-line measurement, it is possible to remotely control the above-described calculation of the membrane filtration resistance value and the air cleaning through the diffuser, and to display the data on the air cleaning of the separator to the operator. This allows the operator to efficiently control the cleaning and operating processes of the membrane filter based on quantified data on air cleaning of the submerged membrane filter.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. The present invention has been described with reference to the embodiments shown in the drawings, which are described as one embodiment by which the technical spirit of the present invention and its core configuration and operation are not limited.

1 is a schematic view showing the configuration of a horizontal immersion membrane filter device as an example of a water treatment device to which the air cleaning method of the immersion membrane according to the present invention is applied.

The horizontal immersion membrane filtration apparatus includes a immersion membrane filtration tank (1), a horizontal immersion membrane module (2) comprising a membrane immersed in the immersion membrane filtration tank (1), and air for cleaning the membrane module. A diffuser 3 equipped with a tornado-jet nozzle 4, a suction pump 6 for filtration and backwashing, a water temperature of filtration water, a filtration pressure (intermembrane pressure), a filtration flow rate, etc. can be measured. The filtration flux (membrane permeation flow rate), the intermembrane differential pressure (TMP) and the water viscosity (Viscosity) using the measured data from the measuring device 7 and the online measuring device 7 (Membrane Resistance), a calculation control section 8 for controlling the air blowing from the diffuser 3 by calculating the change? Rt and? Rs values of the membrane filtration resistance value over time. In the figure, the member number 5 is an air generator 5 for supplying air for washing to the diffuser 3.

The measuring device 7 includes a thermometer 71 capable of measuring the water temperature of the filtered water, a pressure gauge 72 capable of measuring the filtration pressure (intermembrane pressure difference), and a flow meter 73 capable of measuring the filtration flow rate. It includes. The measuring device 7 is preferably configured as an online measuring device capable of transmitting measured values online.

Figure 2 is a graph showing the difference of the filtration flux (J) value according to the length of the membrane in the horizontal immersion membrane filter device (left graph of Figure 2), and the actual horizontal immersion membrane filter device It is a photograph substitute drawing of horizontal submerged membrane module.

2, the vertical axis is the value of the filtration flux, and the horizontal axis is the distance from the outlet. As can be seen in the graph of Figure 2, in the actual horizontal immersion membrane module in the photo of Figure 2 was shown that the largest membrane fouling load is generated about 20cm section of both ends of the membrane module. That is, membrane fouling occurs most severely at both ends of the membrane module.

Therefore, in the present invention, the nozzle 4 of the diffuser 3 is concentrated and disposed within 20 cm of both ends of the membrane module, and the air cleaning amount is concentrated at a position where the membrane fouling load is large to maximize membrane fouling suppression. FIG. 3 shows a schematic plan view of the diffuser 3 provided in the horizontal immersion membrane filtration apparatus according to the present invention. As shown in FIG. 3, the nozzle 4 in the diffuser 3 is a membrane. Both ends of the module, that is, the membrane module is formed intensively at both ends of the diffuser (3) arranged in parallel with the direction arranged horizontally. In particular, in the present invention, the film cleaning air injected from the nozzle 4 is sprayed in a tornado-shaped tornado method. As the air is injected in the tornado-type whirlwind method, the air cleaning efficiency of the membrane module is further increased. By adjusting the angle of the nozzle 4, the air for cleaning the membrane can be sprayed in a tornado type whirlwind method. That is, when the nozzle 4 is formed in an inclined shape, the air for cleaning the film may be injected in a tornado-type cyclone.

In the present invention, an efficient membrane filtration is achieved by adjusting the cleaning cycle of the immersion type membrane module 2 using the method described below, that is, the membrane filtration resistance value.

In Equation 1, J is a filtration flux indicating a unit time and a flow rate filtered per unit area of the membrane module, Q is a filtration flow rate, A is an area of the membrane module, and t is a filtration time.

As described above, the filtration flux J value is calculated by dividing the measured value of the flow meter 73 by the time and the area of the membrane module.

In Equation 2, R denotes a membrane filtration resistance value when the membrane is filtered, μ denotes a viscosity coefficient, and ΔP denotes an intermembrane differential pressure (TMP), and the intermembrane differential pressure is before and after the immersion membrane module (2). As the pressure difference of, the measured value of filtration pressure by the pressure gauge 72 provided at the rear end of the immersion type membrane module 2 becomes a TMP value.

In Equation 3, R ₁ and R ₂ represent film filtration resistance values at times t ₁ and t ₂ , respectively, and the difference between these values becomes ΔR.

ΔR _t in Equation 4 represents a difference in the film filtration resistance value generated between the times t ₁ and t _n . In Equation 5, ΔR _s is a difference between the membrane filtration resistance values at a predetermined unit time interval, that is, a difference between the membrane filtration resistance values during the unit filtration time occurred between the time t _n and t _{n -1} having the unit time interval. Indicates.

FIG. 4 is a graph showing the change of membrane filtration resistance during filtration using an immersion type membrane. In the graph of FIG. 4, the membrane filtration resistance is converted from a linear increase curve to a nonlinear increase curve. The membrane filtration resistance of is represented by R _n , the membrane filtration resistance value at the beginning of filtration is represented by R ₁ , and the difference between R _n and R ₁ is called ΔR _t . Further, the film shows a difference in the filtered resistance value as △ R _s in the unit time interval. In general, the more the membrane fouling proceeds as the filtration is performed using the immersion membrane, the ΔR _s value is greater than 0, and the membrane filtration resistance values are linear and nonlinear irregularities as shown in FIG. 4. Will form an upward growth curve.

In the present invention, the immersion separation membrane is cleaned using the air cleaning method having the configuration described below, so that the difference ΔR _s of the membrane filtration resistance value at unit time intervals is set to 0 or less.

5 is a process flowchart for explaining each step of the air cleaning method according to the present invention.

First, the suction pump 6 is operated to perform membrane filtration through the immersion membrane module 2 immersed in the immersion membrane filtration tank 1 (S1). At this time, aeration is not performed at the beginning of membrane filtration. It includes a thermometer 71 capable of measuring the water temperature of the filtered water, a pressure gauge 72 capable of measuring the filtration pressure (intermembrane differential pressure), and a flow meter 73 capable of measuring the filtration flow rate while the membrane filtration is performed. The water temperature, the intermembrane differential pressure (TMP value), and the filtration flow rate are measured by the measuring device 7 (S2). The arithmetic and control unit 8 calculates the filtration flux J value according to Equation 1 described above by using the measured value by the measuring device 7 (S3).

The calculation controller 8 calculates the membrane filtration resistance value R at each measurement time in accordance with Equation 2 by using the intermembrane differential pressure TMP value, the calculated filtration flux J value, and the measured viscosity coefficient μ. As shown in FIG. 2, data for calculating a graph of the membrane filtration resistance value R according to the filtration time is formed. In addition, the calculation control unit 8 calculates the membrane filtration resistance value R as described above, and calculates the membrane filtration resistance value R _n at the inflection point at which the membrane filtration resistance value is converted from the linear increase curve to the nonlinear increase curve. Calculate the difference ΔR _t (that is, the value of R _n -R ₁ ) from the membrane filtration resistance value R ₁ (S4). The calculated? R _t value is compared with a predetermined set value (for example, 0) (S5). If the calculated value of ΔR _t is less than or equal to the predetermined value, membrane filtration is continued without aeration. If the calculated value of ΔR _t is greater than the value of the predetermined value, it is determined that air cleaning of the separator is necessary. Air is blown through the nozzle 4 of the diffuser 3 in a tornado manner to perform an air cleaning operation of the separator (S6).

The calculation control section 8 continuously calculates the membrane filtration resistance value and calculates the difference ΔR _s of the membrane filtration resistance value at a predetermined unit time interval by Equation 4, and the ΔR _s value is a predetermined reference value ( For example, it is determined whether or not a value of 0) (S7). If the calculated value of ΔR _s is less than or equal to the predetermined reference value, it is determined that the air cleaning of the separator is sufficiently performed, the air cleaning operation is terminated, and the membrane filtration process is continued. The membrane filtration and air cleaning data as described above are stored in a computer or the like and made into a database (S8).

As mentioned above, by configuring the measuring device 7 to enable online measurement, it is possible to remotely control the above-described calculation of the membrane filtration resistance value and the air cleaning through the diffuser 3 online.

In addition, the above data on the air cleaning of the membrane can be displayed to the operator, the operator can efficiently control the cleaning and operation process of the membrane filter based on the quantified data on the air cleaning of the immersion membrane filter You can do it.

1 is a schematic view showing the configuration of a horizontal immersion membrane filter device as an example of a water treatment device to which the air cleaning method of the immersion membrane according to the present invention is applied.

Figure 2 is a graph showing the difference in the filtration flux (J) value according to the length of the membrane in the horizontal immersion membrane filter device, and substitutes the drawing of the horizontal immersion membrane module provided in the actual horizontal immersion membrane filter device It is a photograph.

Figure 3 is a schematic plan view of the diffuser provided in the horizontal immersion membrane filter apparatus according to the present invention.

4 is a graph showing the change of membrane filtration resistance value during filtration using immersion membrane.

 5 is a process flowchart for explaining each step of the air cleaning method according to the present invention.

* Explanation of symbols for the main parts of the drawings

1: submerged membrane filtration tank

2: submerged membrane module

3: diffuser

4: nozzle

5: diffuser

6: pump

7: measuring device

8: operation control unit

Claims (3)

Submerged membrane filtration tank (1), the horizontal immersion membrane module (2) consisting of a membrane immersed in the immersion membrane filtration tank (1), and a nozzle (4) for blowing out the air for cleaning the membrane module The provided diffuser 3, the suction pump 6 for filtration and backwashing, the thermometer 71 for measuring the water temperature of the filtrate, and the pressure gauge 72 for measuring the TMP. ), A flow meter 73 capable of measuring the filtration flow rate, and an arithmetic control unit for determining the air cleaning time using the measured temperature, the filtration pressure, and the filtration flow rate value, and controlling the air blowing through the diffuser 3 ( 8) including; The operation control unit 8, Calculating the filtration flux J value according to Equation 1 using the temperature, the intermembrane pressure difference, and the filtration flow rate values measured during membrane filtration; Using the intermembrane differential pressure TMP value, the calculated filtration flux J value, and the viscosity coefficient μ, the membrane filtration resistance value R at each measurement time was calculated according to Equation 2 below to calculate the membrane filtration resistance value R according to the filtration time. Calculating data capable of forming a; After calculating the membrane filtration resistance value R _n at the inflection point at which the membrane filtration resistance value is converted from the linear increase curve to the nonlinear increase curve, the difference ΔR _t from the membrane filtration resistance value R _{1 at the} beginning of filtration is calculated and then calculated. △ R by the _t values with the pre-set value, or less, calculated △ R _t value of the setting value in the case, and continue to the membrane filtration to the non-aerated conditions, the calculated △ R _t value is greater than the set value, the diffusion pipe The air is blown out through the nozzle 4 of (3) to perform the air cleaning operation of the separation membrane, and the difference ΔR _s between the membrane filtration resistance values at unit time intervals is calculated and the ΔR _s value is a predetermined reference value. The submerged separation membrane filtration apparatus of the automatic air cleaning function, characterized in that the air cleaning operation of the membrane is terminated and the membrane filtration process is continued if the value of ΔR _s is less than or equal to the reference value. (Equation 1)

In Equation 1, J is a filtration flux representing a unit time and a flow rate filtered per unit area of the membrane module, Q is a filtration flow rate, A is an area of the membrane module, and t is a filtration time.) (Equation 2)

(In Equation 2 above, R is the membrane filtration resistance value when the membrane is filtered, ΔP is the transmembrane pressure (TMP), μ is the viscosity coefficient (Viscosity), J is the filtration flux (Flux) value.) The method of claim 1, The nozzle 4 of the diffuser 3 is disposed at both ends of the membrane module, and the air for cleaning the membrane sprayed from the nozzle 4 is sprayed in a tornado-shaped tornado method. Function submerged membrane filtration device. Submerged membrane filtration tank (1), the horizontal immersion membrane module (2) consisting of a membrane immersed in the immersion membrane filtration tank (1), and a nozzle (4) for blowing out the air for cleaning the membrane module The diffuser (3), the suction pump (6) for filtration and backwashing, a thermometer (71) capable of measuring the water temperature of the filtrate, a pressure gauge (72) capable of measuring the interlayer differential pressure, As an automatic air cleaning method of an immersion type membrane filtration apparatus comprising a flow meter (73) capable of measuring the filtration flow rate, and an arithmetic and control unit (8) for controlling the ejection of air through the diffuser (3), Calculating the filtration flux J value by using Equation 1 using the temperature, the intermembrane pressure difference (TMP) and the filtration flow rate values measured during membrane filtration; Using the calculated interlayer differential pressure TMP value, the filtration flux J value, and the known viscosity coefficient μ, the membrane filtration resistance value R at each measurement time was calculated according to Equation 2 below to calculate the membrane filtration resistance according to the filtration time. Calculating data capable of forming a graph of value R; And Calculate the membrane filtration resistance value R _n at the inflection point where the membrane filtration resistance value is converted from the linear increase curve to the nonlinear increase curve, and then calculate the difference △ R _t from the membrane filtration resistance value R _{1 at the} beginning of filtration. a △ R by the _t values with the pre-set value, or below the calculated △ R _t value of the setting value in the case where the and proceed to the membrane filtration to the non-aerated conditions, the calculated △ R _t value larger than the set value, the acid The air is blown out through the nozzle 4 of the engine 3 to perform the air cleaning operation of the separation membrane, and the difference ΔR _s of the membrane filtration resistance value at unit time intervals is calculated and the ΔR _s value is predetermined. Determining whether the reference value is equal to or less than the reference value, and when the ΔR _s value is equal to or lower than the reference value, terminating the air cleaning operation of the separation membrane and continuing the membrane filtration process, and starting and terminating the air cleaning by the operation control unit 8. Is determined Force-air cleaning method of the submerged membrane filtration apparatus, characterized in that to set. (Equation 1)

In Equation 1, J is a filtration flux representing a unit time and a flow rate filtered per unit area of the membrane module, Q is a filtration flow rate, A is an area of the membrane module, and t is a filtration time.) (Equation 2)

(In Equation 2 above, R is the membrane filtration resistance value when the membrane is filtered, ΔP is the transmembrane pressure (TMP), μ is the viscosity coefficient (Viscosity), J is the filtration flux (Flux) value.)

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