KR20080101588A - Operation and design method of membrane filtration water treatment device - Google Patents

Abstract

The present invention relates to a membrane filtration water treatment device, and more particularly, to optimize the membrane filtration water purification device based on the quality of raw water flowing into the membrane filtration water treatment plant or to install a new membrane filtration water treatment plant. Provides a method for designing a filtered water treatment system and a raw water quality monitoring system.

Apparatus for the operation and design method of the membrane filtration purified water treatment device through the raw water quality monitoring according to the present invention, in the membrane filtration water treatment plant, at least one raw water quality measuring device installed in the river to collect the raw water, raw water inlet pipe and A main inlet pressure gauge installed in an inlet pipe connected with a plurality of filtration membranes, a circulating pressure gauge installed in a duct pipe connected to the plurality of filtration membranes communicating with the inlet pipe, and a plurality of filtration membranes, and an outflow communicating with the treated water outlet pipe. A main inlet pressure gauge installed in the main pipe, a sub inlet pressure gauge installed in the inlet pipe where each filtration membrane is in communication, and a sub inlet pressure gauge installed in the outlet pipe where each filtration membrane is in communication, a pH meter installed on the raw water inlet pipe and the treated water outlet pipe, A measuring unit comprising a temperature measuring instrument and a turbidity measuring instrument as a water quality measuring instrument; An operation unit including a control valve installed at the inlet pipe and controlling a flow of raw water supplied to each inlet pipe, and a pressure pump installed at the inlet pipe to control pressure of raw water supplied to each inlet pipe; A backwashing means connected to said outlet pipe and including a tank, a pump and a control valve for supplying a washing liquid; Receiving the water quality and hydraulic pressure-related data input from the measuring unit and characterized in that it comprises a control unit for operating the operation unit and the back washing means in accordance with the operating program.

Description

Operation and Design Method of Membrane Filtration Treatment System and Device for It {Automatic Contro Method and Device for Membrane Filtering System}

1 is a conceptual diagram showing a raw water quality monitoring system,

Figure 2 is a schematic diagram showing a membrane filtration water treatment apparatus according to the present invention,

3 is a schematic diagram showing a membrane filtration system according to the present invention.

4 is a configuration diagram of an experimental apparatus for derivation of operating factors;

5 and 6 are graphs showing the experimental results,

7 is a schematic configuration diagram of a raw water quality monitoring system according to the present invention;

8 is a flow chart showing a design method of a membrane filtration sewage treatment plant according to the present invention.

The present invention relates to a membrane filtration water treatment device, and more particularly, to optimize the membrane filtration water purification device based on the quality of raw water flowing into the membrane filtration water treatment plant or to install a new membrane filtration water treatment plant. It is to provide a method for designing a filtered water treatment system and a raw water quality monitoring system.

As the quality of life continues, the amount of water used is rapidly increasing while the quality of raw water is getting worse. In particular, algae propagation resulted in more backwashing than the usual operation of the filter paper in the water purification plant, which causes many difficulties in the supply of tap water.

Accordingly, an advanced water treatment plant is required, and the advanced water treatment plant is installed in addition to the existing process or replaces the entire existing process in order to remove materials not removed from the existing process. The most well known are advanced oxidation method, ozone oxidation method, activated carbon filtration method, membrane separation method and the like.

In particular, the membrane separation process can reliably control substances and microorganisms larger than the membrane separation process regardless of the raw water quality or process operating conditions. Therefore, a membrane process that continuously obtains safe water quality against sucrose and pathogenic microorganisms is applied to the water treatment process.

Water purification process using membrane separation replaces the existing processes of flocculation, precipitation and filtration with one process. Therefore, since the process itself is more compact and simpler than the conventional treatment process, the processing time is short and the required area of the site is small. And because it does not involve phase change, the energy consumption is small. However, the operation of the membrane separation method requires proper operation depending on the membrane or raw water. In addition, when a new membrane separation process is to be added or newly established, an appropriate scale must be designed based on the operation factors of the membrane separation process to provide stable and economical tap water supply.

The membrane filtration process control method can be classified into pressurized and submerged membrane filtration process control, and the membrane filtration process control method using the dead end method and the membrane flow filtering method using the cross flow method There are process control method and general immersion membrane filtration process control method.

Existing pressure membrane filtration process control method is based on the TMP of the membrane based on the real-time pressure fluctuation values collected from the main inlet pressure gauge installed in the inlet of SKLD consisting of membrane modules, the main inlet pressure gauge installed in the outlet, and the circulating pressure gauge installed in the circulation pipe. When the TMP reaches a value higher than the set value, the filtration process is stopped, the back washing process is performed for a predetermined time, and then the filtration process is performed again.

The general formula of the membrane TMP is as follows.

Membrane TMP = [2 / (inlet pressure + circulation pressure)]-outlet pressure

In the pressurized membrane filtration system, in order to measure the inflow pressure and the outflow pressure required for TMP calculation, a pressure gauge is generally installed at the inlet and main outlet pressure pipes, and a circulating pressure device is installed on the circulation pipe to receive real-time pressure fluctuations. As in the above formula, the range of the pressure fluctuation value is set and filtration or backwashing is performed according to the value.

At this time, the operation reference pressure value of the TMP controls the filtration or backwashing process based on the membrane reference pressure value and the rate of change of the main inflow and outflow pressure based on the midpoint of the SKID module when the installation type of the SKID is installed vertically. In the method of setting the reference pressure value, when the inlet main body is located below the SKID, the elevation of the inlet main body and the intermediate point of the SKID are measured, and the distance is converted into pressure by the distance and set as the SKID reference pressure value.

On the other hand, in the above case, the pressure change in the pressure-conducting pipe through which the incompressible fluid flows is as shown in the following equation.

은 유체의 단위 체적에 의한 중량, V1은 유입주관의 유속, V2는 유출주관의 유속, g는 중력가속도이다.Where P1 is the inlet main pressure, P2 is the outlet main pressure,

Silver is the weight by the unit volume of fluid, V1 is the flow rate of the inlet pipe, V2 is the flow rate of the outlet pipe, and g is the gravitational acceleration.

Therefore, the volume flow rate of the fluid passing through the unit time per unit area of the main inlet and outlet pipes is expressed by the following equation.

Where A is the unit area of the main inlet and B is the unit area of the outlet main.

Substituting the above [Equation 1] and [Equation 2] again as follows.

[Equation 3] is the case of the ideal fluid. Actually, the difference occurs due to the change of the viscosity due to the viscous fluctuation of the fluid, the axial flow condition or the plugging degree between the modules composed of SKID. It is expressed by the following formula.

Therefore, in order to accurately measure the fluctuation pressure between the hydrostatic pressure values measured from the pressure gauges installed at the inlet and outlet pipes and the SKID modules due to the blockage of the membrane itself on the actual pipe, branch pressure devices are installed to provide pressure fluctuations between the main pipe and the branch pipe. By analyzing the factors, it is possible to calculate the average TMP and the maximum and minimum TMP between each SKID group, which enables the automatic control of algorithms by calculating the optimal filtration and backwash operation time between each SKID.

In addition, the determination of the backwashing time of the conventional membrane process control method is determined by the filtration duration, which can reduce the chemical consumption and the power consumption by reducing the backwashing process more than necessary if the accurate calculation of the TPM requiring the actual backwashing is possible. have.

 The present invention provides the ease of maintenance and maintenance of the water treatment system using membrane filtration and provides the operation manager with accurate membrane filtration operation information, and the characteristics of membrane filtration inflow water quality based on the water quality data and the physical change characteristics of the membrane due to continuous filtration. Automatic control method and device for hemofiltration process to operate stable and efficient membrane filtration process by continually guaranteeing the durability of membrane, reducing chemical usage, electricity cost and recovery rate by operating the membrane. To provide.

To this end, the present invention is the main inflow and outflow by on-site data collection device for continuously monitoring the water quality of the raw water flowing into the membrane and to store, manage, and analyze the data, and by interlocking analysis of the physical fluctuation characteristics of the membrane according to the membrane operation In addition, a pressure gauge and a flow meter are installed in the backwash pipe, and a pressure gauge is also installed at branch branches flowing into and out of each membrane, and the operation data collected through this is linked to a higher analysis computer or an operation management computer system, It includes membrane filtration field data collection and control for automatic control with a programmed operating algorithm.

In addition, the apparatus for the operation and design method of the membrane filtration purified water treatment apparatus through the raw water quality monitoring according to the present invention, in the membrane filtration water treatment plant, at least one raw water quality measuring device installed in the river to collect the raw water, and raw water inflow The main inlet pressure gauge installed in the inlet main pipe connected to the pipe and communicating with the plurality of filtration membranes, the circulating pressure gauge installed in the duct pipe connected to the plurality of filtration membranes in communication with the inlet main pipe, and the plurality of filtration membranes and communicating with the treated water outlet pipe. A main inlet pressure gauge installed in the outlet main pipe, a sub inlet pressure gauge installed in the inlet pipe where each filtration membrane is in communication, and a sub inlet pressure gauge installed in the outlet pipe where each filtration membrane is in communication, a pH installed on the raw water inlet pipe and the treated water outlet pipe A measuring unit comprising a measuring instrument, a temperature measuring instrument and a turbidity measuring instrument as a water quality measuring instrument; An operation unit including a control valve installed at the inlet pipe and controlling a flow of raw water supplied to each inlet pipe, and a pressure pump installed at the inlet pipe to control pressure of raw water supplied to each inlet pipe; A backwashing means connected to said outlet pipe and including a tank, a pump and a control valve for supplying a washing liquid; Receiving the water quality and hydraulic pressure-related data input from the measuring unit and characterized in that it comprises a control unit for operating the operation unit and the back washing means in accordance with the operating program.

Operation and design method of the membrane filtration purified water treatment device according to the present invention includes the steps of checking the conditions of selection, such as water source selection, water purification plant size, material to remove; Extracting a configuration of the selectable water treatment system capable of satisfying the examination condition; Selecting an optimum water purification system by analyzing and evaluating the processability, maintenance, construction cost, and required land through an expert system; It characterized in that it comprises a step of designing the number and configuration of the filtration membrane module to satisfy the conditions of the optimum water purification system.

In general, the transmembrane characteristics are affected by the raw water used. In membrane separation, the chemical properties of raw water and the type and content of suspended solids are important. Raw water chemistry is related to the solvent resistance and durability of the membrane. In addition, trace amounts of suspended substances such as fine particles contained in raw water adversely affect the permeation flux of the membrane. That is, it is because of the blockage of membrane pores by SS (Suspended Solids) such as fine particles, colloidal substances, bacteria, and algae contained in raw water. The cleanliness of raw water containing such fine particles is generally expressed in turbidity. Turbidity is suitable for indicating the quality of raw or membrane treated water.

Filtration pressure affects the permeation flow rate of raw water (medium), the blocking rate (or permeability) of the solute or the total filtrate amount (throughput). That is, at high filtration pressures, the particles block the membrane pores more strongly. Therefore, it is difficult to wash by backwashing. For this reason, in the case of filtering raw water containing a suspended substance, the filtration initial stage is filtered at low pressure, and after depositing a low-consolidated cake layer on the membrane surface to some extent, the pressure is gradually increased or low pressure filtration is performed from the beginning with small permeate flux. In order to reduce the frequency of washing to increase the membrane life, operation is required.

In general, the permeate flux increases as the circulation flow rate (membrane flow rate) increases. That is, the permeate flux increases by flowing or stirring the liquid near the membrane surface. Methods of increasing the membrane surface velocity include crossflow, agitation by means of a rotating plate or agitating blades, installation of a sama plate, and rotation of the membrane. However, depending on the filtration conditions, the permeate flux sometimes decreases as the membrane velocity increases. For example, when the suspended particles are filtered, the deposited state of the cake deposited on the membrane surface is affected by the flow state of the root surface, and a dense cake with a higher resistivity of the case may be formed at the flow rate of the membrane surface.

Membrane separation performance of gas, dissolved and suspended substances in all membrane modules is due to the interaction of the membrane with co-existent substances in feed gas or raw water. Substances that cause a decrease in membrane performance are generally called fouling inducing agents. In general, when raw water contains a substance that reacts with the separator, the membrane is deteriorated, and the membrane is dissolved, cracks are generated, and the hydrophilicity of the membrane is generated. As a countermeasure in such a case, the impurity gas is removed by resistance to these impurity gases, selection of a certain membrane or washing of the feed gas by scribing, use of an adsorbent such as activated carbon and a catalyst.

In order to satisfy the requirements as described above, the present invention installs one or more raw water quality measuring devices on the river intake of raw water. The raw water quality measuring device measures the number of algae individuals as well as BOD, COD, DO, pH, turbidity, and the like. The measured data is transmitted to the server through the internet network.

In addition, in the prior art, the main inlet pressure gauge for measuring the pressure of inlet water and the main inlet pressure gauge for measuring the pressure of the inlet water are installed in the inlet and outlet pipes with a plurality of filtration membranes installed in the present invention. A sub inlet pressure gauge for measuring the pressure of the influent and a sub outlet pressure gauge for measuring the pressure of the outlet is installed on the outlet side. This makes it possible to measure the permeate plus of each filtration membrane. Then, a ring pressure gauge for measuring the pressure of the circulating water is provided in the flue pipe.

On the other hand, the pH measuring instrument, the temperature measuring instrument and turbidity measuring instrument installed on the raw water inlet pipe and the treated water outlet pipe is provided with a measurement unit consisting of a water quality meter. And an operation unit including a control valve installed at the inlet main pipe to control the flow of raw water supplied to each inlet main body, and a pressure pump installed at the inlet main pipe to control the pressure of the raw water supplied to each inlet main pipe. . In addition, there is provided a backwashing means connected to the outlet pipe and including a tank, a pump and a control valve for supplying a washing liquid.

Subsequently, the control unit receives water quality and hydraulic pressure-related data input from the measurement unit and operates the operation unit and the back washing means according to an operation program. The control unit is connected to the monitor server and the field computer. Therefore, the control unit controls the pressure of the inflow water by controlling the pressure pump according to the water quality of the raw water and the operating state of the filtration membrane measured through the measurement unit, controlling each control valve and selectively operating the washing means to prevent contamination of the filtration membrane. It also prevents and maintains an optimal operating condition.

Hereinafter, an experimental example for deriving an optimal operating factor for the design of the water treatment system according to the present invention. In this experiment, two membrane modules were connected in series to obtain basic permeate flux data, and the permeate flow rate and water quality of the treated water were measured while varying the operating pressure and the membrane surface velocity.

As shown in Figure 4, in this experimental device, the raw water is attached to the concentration tank by the amount of water passed through the treated water in the state pressurized by the position head by attaching a float valve at the end of the inlet of the raw water. Next, the raw water in the concentration tank is pressurized by the pressure pump to be pressurized and supplied to the membrane separation device. The pressurized raw water enters the pressure-resistant module and the treated water exits the surface of the membrane and enters the treatment tank. At the outlet of the separator, the raw water, which has a higher concentration than the inlet, is introduced again into the concentration tank through the circulation water line. The concentrated circulating water is then mixed with the raw water introduced as much as the treated water which has passed out, and then supplied to the inside of the separator. In the concentration tank, the concentration continuously increases in proportion to the amount of permeated water. For this reason, it is understood that the concept of the concentration tank rather than the raw water tank, and the feed water coming out from the concentration tank and supplied to the membrane is called concentrated water.

In this experiment, the recovery was fixed at 98% to maintain the concentration of the concentrated water. The operation method adopts the cross flow method which is mainly used in the tubular separator. In this experiment, the experiment was performed while varying the pressure and membrane velocity to derive the optimal operating factors. And a chemical cleaning line for chemical cleaning was installed. In this way, the filtration pressure and membrane surface velocity of various conditions were changed while washing the membrane, and the rate of condensation and the amount of filtered water were observed to analyze the progress of membrane contamination and the effect of membrane contamination on membrane performance. The results were analyzed to determine the most appropriate filtration pressure and membrane flow velocity among the target water.

As shown in FIG. 5 and FIG. 6, as a result of the experiment, the tubular ultrafiltration membrane obtained the following results. Filtration pressure 2kgf / ㎠ Membrane flow velocity 3m /, with the permeate flux 150ℓ / ㎡ · hr corrected to filtration pressure 2kgf / ㎠ by operating under filtration pressure 0.35 ~ 0.47kgf / ㎠ and membrane surface velocity 2.04m / s. As a result of operating s as a driving factor, a permeate flux of 70 L / m 2 · hr was obtained.

In addition, the higher the flow velocity, the longer the operating time. This is because the membrane flow velocity suppresses the contamination of the membrane by inhibiting the deposition of contaminants on the membrane surface by the flow velocity passing through the membrane surface. At the operating pressure of 0.35 ~ 0.47kgf / ㎠ and the membrane flow velocity 2.04m / s, the permeation flow rate decreased continuously until the operation accumulation time was 1000 hours.The operating pressure was 2kgf / ㎠ and the membrane flow velocity was 3m. In the case of / s, when the operation time reached 1000 hours, the flux was increased or maintained.

Therefore, the driving factors were determined as follows. In case of water treatment using tubular ultrafiltration membrane, permeate flux is suitable about 70ℓ / ㎡ · hr ~ 80ℓ / ㎡ · hr and the operating pressure is 1.5kgf / ㎠ ~ 2.0kgf / ㎠ Membrane flow rate is about 2.5m / s ~ 3.0m / s. In order to solve the problem of euro occlusion, it is necessary to maintain a certain level of membrane flow velocity. And in order to solve the economic problem, a certain amount of transmission flux must be secured.

7 is a schematic configuration diagram of a raw water quality monitoring system according to the present invention, and FIG. 8 is a flowchart showing a design method of a membrane filtration sewage treatment plant using the same. As shown, the present invention is an automatic design expert system consisting of an application server, an expert system (artificial intelligence / Clips) engine, a natural language interpreter (Lawgic), a rule (knowledge base), and a rule manager. The expert system can optimally program the knowledge of experts in a certain field, and it is designed to derive accurate answers toward the accumulation of knowledge by learning functions.

The present invention is a basic information input step, the step of converting according to the expert system engine based on the input information, natural language analysis step, rule search step, passing the inferred optimal solution to the design engine / server, the target site It consists of extracting geographic information from GIS DB and outputting design diagram.

The present invention implements a system capable of a comprehensive consulting service function in which all the information is provided from one site (site) from the related legal review to the filtration membrane module design, the feasibility review, and the feasibility review based on the quality of raw water as described above. In addition, by implementing the program so that anyone, not only experts but also the general public, can easily use it, it is possible to implement a popularization service of consulting that users can self-diagnose themselves.

As described above, the present invention accurately analyzes and checks the exact operating state of the membrane by interlocking the membrane filtration process equipment such as a pump valve by accurately analyzing the physical change factors of the membrane fluctuated according to the fluctuation of the membrane inflow water and the continuous membrane filtration operation. It is possible to improve the durability of the membrane and to reduce chemical consumption and power consumption by ensuring a stable recovery rate and correct and proper operation considering the physical structure of the membrane.

Claims (3)

In membrane filtration water treatment plant, One or more raw water quality measuring devices installed in the intake of the raw water, the main inlet pressure gauge installed in the inlet pipe which is connected with the raw water inlet pipe, and the plurality of filtration membranes, and the effluent which is connected with the plurality of filtration membranes and in communication with the treated water outlet pipe. The main outlet pressure gauge installed in the main pipe, the circulation pressure gauge installed in the flue pipe connected to the plurality of filtration membranes in communication with the inlet pipe, the sub inlet pressure gauge installed in the inlet pipe through which each filtration membrane is connected, and the outlet pipe through which each filtration membrane is connected. A measuring unit comprising a sub inlet pressure gauge, a pH meter, a temperature meter, and a turbidity meter installed on the raw water inlet pipe and the treated water outlet pipe; An operation unit including a control valve installed at the inlet pipe and controlling a flow of raw water supplied to each inlet pipe, and a pressure pump installed at the inlet pipe to control pressure of raw water supplied to each inlet pipe; A backwashing means connected to said outlet pipe and including a tank, a pump and a control valve for supplying a washing liquid; Apparatus for operating and designing a membrane filtration water treatment apparatus comprising a control unit for receiving the water quality and hydraulic pressure-related data input from the measuring unit and operating the operation unit and the back washing means according to an operation program. . In membrane filtration water treatment plant, One or more raw water quality measuring devices installed in the intake of the raw water, the main inlet pressure gauge installed in the inlet pipe which is connected with the raw water inlet pipe, and the plurality of filtration membranes, and the effluent which is connected with the plurality of filtration membranes and in communication with the treated water outlet pipe. The main outlet pressure gauge installed in the main pipe, the circulation pressure gauge installed in the flue pipe connected to the plurality of filtration membranes in communication with the inlet pipe, the sub inlet pressure gauge installed in the inlet pipe through which each filtration membrane is connected, and the outlet pipe through which each filtration membrane is connected. A measuring unit comprising a sub inlet pressure gauge, a pH meter, a temperature meter, and a turbidity meter installed on the raw water inlet pipe and the treated water outlet pipe; An operation unit including a control valve installed at the inlet pipe and controlling a flow of raw water supplied to each inlet pipe, and a pressure pump installed at the inlet pipe to control pressure of raw water supplied to each inlet pipe; A backwashing means connected to said outlet pipe and including a tank, a pump and a control valve for supplying a washing liquid; Operation of the membrane filtration purified water treatment device through the raw water quality monitoring, characterized in that it comprises a control unit for receiving the water quality and hydraulic pressure-related data input from the measuring unit and operating the operation unit and the back washing means in accordance with the operating program and Design method. The method of claim 2, Confirming review conditions such as selection of water source, water purification plant size, material to be removed; Extracting a configuration of the selectable water treatment system capable of satisfying the examination condition; Selecting an optimum water purification system by analyzing and evaluating the processability, maintenance, construction cost, and required land through an expert system; And designing the number and configuration of the filtration membrane modules so as to satisfy the conditions of the optimum water purification system.

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