KR102110441B1 - The control method for ammonia removal system - Google Patents

Abstract

Disclosed is a control method for an ammonia removal system. According to the present invention, the control method for an ammonia removal system comprises the steps of: (a) if an initial ammonia concentration of incoming water stored in a flow storage tank and supplied to a membrane contactor is equal to or less than a set value, releasing the incoming water stored in the flow storage tank to the outside; (b) if the initial ammonia concentration is greater than the set value, circulating the incoming water and an absorbent solution in the membrane contactor to remove ammonia from the incoming water by means of a hydrophobic separator inside the membrane contactor, measuring an ammonia concentration of treatment water released from the membrane contactor after a predetermined time, and if the ammonia concentration of the treatment water is equal to or less than the set value, releasing the treatment water to the outside; (c) if the ammonia concentration of the treatment water measured after a predetermined time is greater than the set value, calculating an initial mass transfer coefficient of the hydrophobic separator from the ammonia concentration of the treatment water; (d) from the calculated initial mass transfer coefficient, calculating an initial estimated time for the ammonia concentration of the treatment water released from the membrane contactor to reach a set value; and (e) if the ammonia concentration of the treatment water released from the membrane contactor is equal to or less than the set value at the calculated initial estimated time, releasing the treatment water to the outside.

Description

Control method of ammonia removal system {THE CONTROL METHOD FOR AMMONIA REMOVAL SYSTEM}

The present invention relates to a control method of an ammonia removal system, and more particularly, to a control method of an ammonia removal system that can reduce operating costs.

Ammonia is produced in large quantities in wastewater from various fields such as industrial and food and livestock waste.

It is common for wastewater containing high concentration ammonia to be treated using a physicochemical reaction, and wastewater containing low concentration ammonia to be treated using a biological nitrification-denitrification reaction.

The ammonia removal system using a physicochemical reaction may include a membrane contactor to adjust the ammonia concentration to a target concentration. When the ammonia removal system includes a membrane contactor, the size and required equipment of the ammonia removal system is reduced compared to the system including the ammonia adsorption tower, which is advantageous in designing and operating the system.

However, even when using the conventional ammonia removal system using a membrane contactor, considering the ammonia concentration, temperature, flow rate, pH of the raw water flowing into the membrane contactor and the mass transfer coefficient (k _m ) of the hydrophobic separator used in the membrane contactor Since the system is operated, excessive facilities are required according to the system operation, and there is a problem in that operating costs such as an increase in equipment cost due to excessive equipment and power usage due to power consumption due to equipment operation are increased.

Republic of Korea Patent Registration No. 10-1997846 (2019.07.08.announcement)

Therefore, the technical problem to be solved by the present invention is to calculate the estimated time required to process raw water containing ammonia from the mass transfer coefficient of the hydrophobic separator, and measure the ammonia concentration of the treated water in accordance with the expected time to measure the amount of ammonia in the treated water. It is to provide a control method of the ammonia removal system that can determine whether the concentration has reached the set value, thereby minimizing excessive equipment operation and thus reducing operating costs associated with equipment operation.

According to an aspect of the present invention, (a) when the initial ammonia concentration of the inflow water stored in the flow rate storage tank and supplied to the membrane contactor is less than a set value, discharging the inflow water stored in the flow rate storage tank to the outside; (b) When the initial ammonia concentration is greater than the set value, the ammonia contained in the influent is removed by using a hydrophobic separation membrane in the membrane contactor by circulating the influent and the absorption solution to the membrane contactor, but after a predetermined time has elapsed Measuring the ammonia concentration of the treated water discharged from the apparatus and discharging the treated water to the outside when the ammonia concentration of the treated water is equal to or less than a set value; (c) calculating an initial mass transfer coefficient of the hydrophobic separation membrane from the ammonia concentration of the treated water when the ammonia concentration of the treated water measured after a predetermined period of time is greater than a set value; (d) calculating an initial estimated arrival time for the ammonia concentration of the treated water discharged from the membrane contactor from the calculated initial mass transfer coefficient to reach a set value; And (e) discharging the treated water to the outside when the ammonia concentration of the treated water discharged from the membrane contactor is less than or equal to a set value at the calculated initial expected arrival time. have.

In the step (c), (c-1) determining whether the hydrophobic separator is contaminated according to the film wetting phenomenon from the calculated initial mass transfer coefficient, and stopping the alarm or system operation according to the degree of contamination of the hydrophobic separator. It may further include.

The step (c-1) may include stopping the system operation when the calculated initial mass transfer coefficient is equal to or less than the shutdown mass transfer coefficient of the hydrophobic separator; Generating a threshold efficiency reaching alarm indicating that the hydrophobic separator has reached a limit when the calculated initial mass transfer coefficient is equal to or less than the threshold mass transfer coefficient of the hydrophobic separator; And when the calculated initial mass transfer coefficient is equal to or less than an intermediate value between the mass transfer coefficient and the limit mass transfer coefficient before use of the hydrophobic separator, generating a washing recommendation alarm indicating that the hydrophobic separator needs to be cleaned. have.

(f) When the ammonia concentration of the treated water discharged from the membrane contactor is greater than a set value at the calculated initial expected arrival time, the hydrophobicity is calculated from the ammonia concentration of the treated water discharged from the membrane contactor at the initial expected arrival time. Recalculating the mass transfer coefficient of the separator; (g) recalculating the estimated arrival time for the ammonia concentration of the treated water discharged from the membrane contactor from the recalculated mass transfer coefficient to reach a set value; And (h) discharging the treated water to the outside when the ammonia concentration of the treated water discharged from the membrane contactor is less than or equal to the set value at the estimated recalculated arrival time.

The step (f) is (f-1) determining whether the hydrophobic separator is contaminated according to the film wetting phenomenon from the recalculated material transfer coefficient, and stopping the alarm or system operation according to the degree of contamination of the hydrophobic separator. It may further include.

The step (f-1) may include stopping the operation of the system when the recalculated mass transfer coefficient is equal to or less than the shutdown mass transfer coefficient of the hydrophobic separator; Generating a limit efficiency reaching alarm informing that the hydrophobic separator has reached a limit when the recalculated material transfer coefficient is equal to or less than the limit material transfer coefficient of the hydrophobic separator; And when the recalculated material transfer coefficient is less than or equal to an intermediate value between the material transfer coefficient and the limit material transfer coefficient before use of the hydrophobic separator, generating a washing recommendation alarm indicating that the hydrophobic separator needs to be cleaned. have.

(a-1) Before the step (a), a pretreatment step of removing foreign substances contained in the inflow water supplied to the membrane contactor may be further included.

(a-1) Before the step (a), the step of adjusting the temperature and pH of the influent supplied to the membrane contactor may be further included.

(a-2) The step (a) may further include the step of constantly adjusting the temperature and pH of the absorption solution supplied to the membrane contactor.

The embodiment of the present invention calculates the estimated time required to process raw water containing ammonia from the mass transfer coefficient of the hydrophobic membrane, and measures the ammonia concentration of the treated water at the expected time to reach the ammonia concentration of the treated water at a set value. Since it can be determined whether or not it has been reached, it is possible to minimize excessive equipment operation in operating the system, thereby reducing operating costs associated with operating the equipment.

In addition, the embodiment of the present invention can grasp the film wetting phenomenon of the hydrophobic separator from the mass transfer coefficient of the hydrophobic separator, so that the system can be stably operated in response to the film wetting phenomenon of the hydrophobic separator.

1 is a view showing an ammonia removal system according to the present invention.
Figure 2 is a flow chart showing a control method of the ammonia removal system according to the present invention.
3 is a flow chart showing a method for determining whether or not contamination of a hydrophobic separator according to an initial mass transfer coefficient (k _{m_ini} ) according to the present invention.
Figure 4 is a flow chart showing a method for determining whether the hydrophobic separation membrane according to the recalculated mass transfer coefficient (k _{m_t1} ) according to the present invention.

In order to fully understand the present invention, the operational advantages of the present invention, and the objects achieved by the practice of the present invention, reference should be made to the accompanying drawings and the contents described in the accompanying drawings, which illustrate preferred embodiments of the present invention.

Hereinafter, the present invention will be described in detail by explaining preferred embodiments of the present invention with reference to the accompanying drawings. The same reference numerals in each drawing denote the same members.

1 is a view showing an ammonia removal system according to the present invention.

Referring to FIG. 1, the ammonia removal system 100 according to the present invention is supplied with raw water storage tank 10 for storing raw water, pretreatment unit 20 for removing foreign substances contained in raw water, and pretreated raw water. A flow rate adjustment tank 30, a membrane contactor 40 for removing ammonia contained in the inflow water supplied from the flow rate adjustment tank 30 using a hydrophobic separation membrane 45, and a control unit for controlling the overall operation of the system (not shown) Poetry).

In this embodiment, the control unit measures and controls the ammonia concentration and flow rate and temperature and pH of the influent water, measures and controls the concentration and flow rate and temperature and pH of the absorption solution, and of the treated water processed by the membrane contactor 40. It is determined whether the ammonia concentration has reached the set value, calculates the mass transfer coefficient of the hydrophobic separation membrane 45, determines whether the hydrophobic separation membrane 45 is contaminated from the calculated mass transfer coefficient, and calculates the mass transfer coefficient from the calculated mass transfer coefficient. The overall ammonia removal system 100 is controlled, such as calculating the estimated time to reach the ammonia concentration of the treated water treated by the membrane contactor 40 to reach a set value.

The raw water storage tank 10 stores raw water containing contaminants such as ammonia and various organic and inorganic substances. That is, the raw water may be wastewater, sludge, fresh water, brackish water, seawater, and reverse osmosis process concentrated water containing contaminants.

In addition, the pre-treatment unit 20 serves to remove foreign substances contained in raw water.

In FIG. 1, the pre-treatment unit 20 is disposed at the rear of the raw water storage tank 10 and is shown to remove foreign substances contained in raw water supplied from the raw water storage tank 10, but is disposed in front of the raw water storage tank 10 to store the raw water storage tank. The foreign material contained in the raw water supplied to (10) may be pre-treated.

Meanwhile, in FIG. 1, one pre-treatment unit 20 is illustrated, but is not limited thereto, and a plurality of pre-treatment units 20 may be continuously installed depending on the flow rate of raw water, the scale of the membrane contactor 40, and the use environment. .

In addition, in Figure 1, the pre-treatment unit 20 is shown in the form of a storage tank, but the form is not specified. For example, the pre-treatment unit 20 may be inserted into the inside of the pipe connected to the raw water storage tank 10 and the membrane contactor 40, or may be in the form of a device installed outside the pipe.

On the other hand, the pre-treatment unit 20 is mainly a device for controlling foreign substances that may occur in the process, such as particles, microorganisms, organic substances, inorganic substances. Particularly, control may be necessary because particles, organic substances, and microorganisms can be combined with inorganic substances in a complex manner.

To this end, the pre-treatment unit 20 performs any one or more of an inorganic ion control process, an organic material control process, a microbial control process, and a particle control process.

More specifically, the pretreatment unit 20 is agglomeration, sedimentation, filtration (sand filtration, dual media filtration, multi-media filtration, cartridge filter, microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), reverse osmosis (RO) ), MD (membrane distillation), FO (Forward osmosis) membrane, sterilization (HOCl, NaOCl, UV irradiation), microbial process, ion exchange, softening, chemical treatment (acid, base, disinfectant, detergent, Anti-scalant), adsorption (active carbons, filter absorbers, resins, etc.).

In addition, the flow adjustment tank 30 may be provided at the rear of the pre-treatment unit 20 and the raw water storage tank 10 separately from the pre-treatment unit 20. The flow adjustment tank 30 is connected to the pre-treatment unit 20 to receive and store pre-processed raw water, and the raw water stored in the flow adjustment tank 30 is supplied to a membrane contactor 40 to be described later, and the membrane contactor 40 The treated water discharged from the inlet flows back into the flow adjustment tank 30 and is stored.

In this embodiment, the flow adjustment tank 30 constitutes a closed loop with the membrane contactor 40, and is discharged from the raw water and the membrane contactor 40 stored in the flow adjustment tank 30 through the pre-treatment unit 20, and the flow adjustment tank ( All the treated water introduced into 30) forms influent supplied to the membrane contactor 40.

In this embodiment, the ammonia contained in the inflow water is sequentially removed while the inflow water is circulated between the flow adjustment tank 30 and the membrane contactor 40.

As described above, the membrane contactor 40 serves to remove ammonia contained in the inflow water supplied from the flow adjustment tank 30.

The membrane contactor 40 includes a hydrophobic separation membrane 45 provided between the influent chamber 41 through which the influent flows, the absorption liquid chamber 43 through which the absorption solution flows, and the influent chamber 41 and the absorption liquid chamber 43. ).

Sulfuric acid may be used as the absorption solution flowing into the absorption solution chamber 43, but is not limited thereto, and may be changed according to processes such as phosphoric acid, which is an acid family. The absorbing solution is stored in the absorbing solution storage tank 50 connected to the membrane contactor 40, and acid-based chemicals such as sulfuric acid may be mixed in the absorbing solution storage tank 50.

In this embodiment, the hydrophobic separation membrane 45 is shown as a flat membrane, but the hydrophobic separation membrane 45 is also applicable to a hollow fiber membrane, a tube shape, and the like.

And the hydrophobic membrane 45 is polytetrafluoroethylene (Polytetrafluoroethylene, PTFE), polyvinylidene fluoride (PVDF), polysulfone (polysulfone, PSF), polyether sulfone (Polyether sulfone, PES), polyetherimide (Polyether lmide, PEI), polyimide (Polyimide, PI), polyethylene (Polyethylene, PE), polypropylene (Polypropylene, PP) and polyamide (Polyamide, PA) can be made of any one.

Membrane contactor 40 according to the present embodiment is due to the partial pressure difference of the ammonia between the inflow water chamber 41 and the absorption solution chamber 43 bordering the hydrophobic separation membrane 45, the solutions on both sides cannot pass each other and are volatile. Only ammonia gas is selectively moved through the hydrophobic membrane 45. That is, after the ammonia in the influent chamber 41 diffuses and moves to the boundary surface of the hydrophobic separator 45, it is volatilized with ammonia gas at the contact surface with the hydrophobic separator 45, passes through the hydrophobic separator 45, and then absorbs the solution chamber ( Upon contact with the sulfuric acid solution in 43), it is dissolved again in the form of ammonium sulfate.

In addition, the treated water from which the ammonia has been removed from the influent chamber 41 is supplied from the influent chamber 41 to the flow adjusting tank 30 and then supplied to the influent chamber 41 again between the influent chamber 41 and the flow adjusting tank 30. Is circulated in. Meanwhile, ammonium sulfate dissolved in the absorption solution is stored in a separate compound storage tank 60 connected to the absorption solution storage tank 50.

As described above, the ammonia-containing influent water is circulated between the flow adjustment tank 30 and the influent chamber 41, and the ammonia contained in the influent water is moved to the absorption solution side through the hydrophobic separator 45 and is removed.

On the other hand, when the process of removing the ammonia contained in the influent by using the hydrophobic separator 45 for a long time, the hydrophobic separator 45 is exposed to the influent containing contaminants such as organic and inorganic substances, and the hydrophobic separator 45 In some cases, membrane contamination, especially wetting, may occur.

When wetting is a phenomenon in which hydrophilic contaminants (for example, Ca-based crystals) are formed inside the pores of the hydrophobic separation membrane 45 and become hydrophilic, the contaminated water in the influent chamber 41 is formed in the hydrophobic separation membrane 45. It refers to being passed directly to the absorption solution chamber (43).

When the film wetting phenomenon occurs, the mass transfer coefficient (k _m ) of the hydrophobic separation membrane 45 is lowered, and thus the ammonia removal efficiency is lowered, so that the target ammonia removal efficiency cannot be achieved. In addition, when the film wetting phenomenon is intensified, contaminated water may pass through the hydrophobic separator 45 and pass to the absorption solution chamber 43 side.

When the film wetting phenomenon occurs, since the contaminated water permeates into the absorption solution chamber 43, ammonia removal efficiency using the hydrophobic separation membrane 45 is significantly reduced. Therefore, when the film wetting phenomenon occurs, the hydrophobic separator 45 must be cleaned or replaced.

Conventionally, the film wetting phenomenon was observed by measuring the electrical conductivity, but this had a problem in that the film wetting phenomenon could be confirmed after the inflow water was moved to the absorption solution chamber 43. In addition, the conventional method has a problem that is unpredictable when the membrane contamination occurs partially or when the hydrophobic separator 45 is partially damaged or heterogeneous and appears only in a part of the hydrophobic separator 45.

Accordingly, in this embodiment, the initial ammonia concentration of the influent water and the ammonia concentration of the treated water discharged from the membrane contactor 40 after a predetermined period of time are measured to transfer the material of the hydrophobic separation membrane 45 from the following equations (1) and (2). After calculating the coefficient, the membrane wetting phenomenon of the hydrophobic separator 45 is determined from the calculated mass transfer coefficient (k _m ) of the hydrophobic separator 45.

---- 식(1)

---- Expression (1)

---- 식(2)

---- Expression (2)

Here, C _o [mg / l] is the initial ammonia concentration of the influent, C _t [mg / l] is the ammonia concentration of the treated water discharged from the membrane contactor 40 at the reaction time t [h], k _m [ m / h] is the ammonia mass transfer coefficient of the hydrophobic separator 45, A [m ² ] is the surface of the hydrophobic separator 45, V _o [m ³ ] is the volume of the influent chamber 41, FA is The fraction of free ammonia in the influent, and pH is the pH of the influent.

In this embodiment, the temperature and pH of the influent are kept constant, and the free ammonia fraction increases under FA conditions.

The surface area A of the hydrophobic separator 45 used in the membrane contactor 40 and the volume V _o of the influent chamber 41 are determined according to the processing capacity of the membrane contactor 40, and the influent according to the pH of the influent from equation (2) Since the free ammonia fraction FA can be calculated, the control unit can be calculated from the initial ammonia concentration (C _o ) of the measured influent and the ammonia concentration (C _t ) of the treated water discharged from the membrane contactor 40 at the reaction time t. ) To calculate the ammonia mass transfer coefficient (k _{m_t} ) of the hydrophobic separator 45 at the reaction time t.

After calculating the response ammonia mass transfer coefficient (k _{m_t)} of the hydrophobic membrane (45) at time t as described above, the control ammonia mass transfer coefficient of the hydrophobic membrane 45 calculated by the response time t (k _{m_t)} is hydrophobic membrane to the intermediate value between the use of the hydrophobic membrane (45) before the mass transfer coefficient (k _{m_o)} and a hydrophobic membrane treatment at the maximum pollution load inlet of the 45 possible limits mass transfer coefficient (k _{m_2)} (k _{m_1)} or less (45) A washing recommendation alarm is generated to notify that cleaning is to be performed. Here, the mass transfer coefficient (k _{m_o} ) before the use of the hydrophobic separator 45 is a mass transfer coefficient in the specification of the hydrophobic separator 45 before removing ammonia contained in the influent using the hydrophobic separator 45.

In addition, the control unit _reaches the limit when the ammonia mass transfer coefficient (k _{m_t} ) of the hydrophobic separation membrane 45 calculated at the reaction time t is less than or equal to the limit mass transfer coefficient (k _{m_2} ) of the hydrophobic separation membrane 45. It generates an alarm to reach the limit efficiency.

In addition, the control unit has an ammonia mass transfer coefficient (k _{m_t} ) of the hydrophobic separation membrane 45 calculated at the reaction time t is less than or equal to a shutdown mass transfer coefficient (k _{m_3} ), where the hydrophobic separation membrane 45 is completely _wetted . In case the system is stopped.

As described above, the present embodiment can grasp the film wetting phenomenon of the hydrophobic separator 45 from the mass transfer coefficient (k _{m_t} ) of the hydrophobic separator 45 at the reaction time t, in response to the film wetting phenomenon of the hydrophobic separator 45 The system can be operated stably.

In addition, the control unit reaches the expected amount of ammonia concentration of the treated water discharged from the membrane contactor 40 from the ammonia mass transfer coefficient (k _{m_t} ) of the hydrophobic separation membrane 45 calculated at the reaction time t reaches the set value (C _f ). The time t _{f_t} can be calculated.

That is, assuming that the hydrophobic membrane 45 of the ammonia mass transfer coefficient (k _{m_t)} the estimated arrival time (t _{f_t)} ammonia mass transfer coefficient (k _{m_f)} of the hydrophobic membrane (45) in the calculation at a reaction time t, Hydrophobic separation membrane at the set value (C _f ) of the initial ammonia concentration (C _o ) of the influent measured in Equation (1) and the ammonia concentration of the treated water discharged from the membrane contactor (40) and the estimated time of arrival (t _{f_t} ) ( The estimated arrival time (t _f ) is calculated by substituting the ammonia mass transfer coefficient of 45) (k _{m_t} ), the surface area A of the hydrophobic membrane 45, the volume V _o of the influent chamber 41, and the free ammonia fraction FA in the influent. Can be.

Therefore, this embodiment measures whether the ammonia concentration of the treated water has reached the set value (C _f ) by measuring the ammonia concentration of the treated water discharged from the membrane contactor 40 at the estimated expected arrival time (t _f ). By doing so, it is possible to minimize the number of measurements of ammonia concentration in the treated water and also to minimize the excessive operation of the equipment in operating the system, thereby reducing the operating cost of operating the equipment.

In addition, the control unit may control to maintain a constant temperature and pH of the inflow water in the flow adjustment tank 30. In order to keep the temperature of the influent in the flow adjustment tank 30 constant, the temperature of the pre-treated raw water flowing in the flow adjustment tank 30 and the treated water discharged from the membrane contactor 40 may be controlled by a heat exchanger (not shown). Can be. In addition, in order to keep the pH of the influent in the flow adjustment tank 30 constant, the pH of the inflow water in the flow adjustment tank 30 may be measured, and a base chemical such as sodium hydroxide may be mixed in the flow adjustment tank 30.

In addition, the control unit controls the flow rate of the inflow water supplied to the inflow chamber 41 of the membrane contactor 40 to be kept constant. The flow rate of the influent water supplied to the influent chamber 41 is determined in consideration of the processing capacity of the membrane contactor 40, and the flow rate of the influent water supplied to the influent chamber 41 is controlled so that the maximum flow rate can be supplied.

In addition, the control unit may control to maintain a constant temperature and pH of the absorption solution in the absorption solution storage tank (50). In order to keep the temperature of the absorption solution in the absorption solution storage tank 50 constant, the temperature of the absorption solution introduced into the absorption solution storage tank 50 may be controlled by a heat exchanger (not shown). In addition, in order to keep the pH of the absorption solution in the absorption solution storage tank 50 constant, the pH of the absorption solution in the absorption solution storage tank 50 is measured and acid-based chemicals such as sulfuric acid can be mixed in the absorption solution storage tank 50. .

In addition, the control unit controls the flow rate of the absorption solution supplied to the absorption solution chamber 43 of the membrane contactor 40 to be kept constant. The flow rate of the absorption solution supplied to the absorption solution chamber 43 is determined in consideration of the processing capacity of the membrane contactor 40, and the flow rate of the absorption solution supplied to the absorption solution chamber 43 is controlled so that the maximum flow rate can be supplied. .

The control method of the ammonia removal system 100 according to the present invention configured as described above is as follows.

Figure 2 is a flow chart showing a control method of the ammonia removal system according to the present invention, Figure 3 is a flow chart showing a method for determining whether the hydrophobic separation membrane according to the initial mass transfer coefficient (k _{m_ini} ) according to the present invention, 4 is a flow chart showing a method for determining whether or not contamination of the hydrophobic membrane according to the recalculated material transfer coefficient (k _{m_t1} ) according to the present invention.

2 to 4, the ammonia removal system 100 according to the present embodiment supplies the inflow water stored in the flow adjustment tank 30 to the inflow water chamber 41 and flows the treated water discharged from the inflow water chamber 41 It forms a closed circulation loop which is supplied to the adjustment tank 30 and stored, and then supplied to the influent chamber 41 again.

In addition, the ammonia removal system 100 according to the present embodiment supplies the absorption solution stored in the absorption solution storage tank 50 to the absorption solution chamber 43 and supplies the treated water discharged from the absorption solution chamber 43 to the absorption solution storage tank 50 ) To form a closed circulation loop that is supplied to the storage solution and then supplied to the absorption solution chamber 43 again.

And the ammonia removal system 100 according to the present embodiment is contained in the influent by using the ammonia partial pressure difference between the influent chamber 41 and the absorption solution chamber 43 at the boundary of the hydrophobic separator 45 of the membrane contactor 40. The removed ammonia is selectively moved to the absorption solution chamber 43 to remove it.

In the present embodiment, the operation of the ammonia removal system 100 is minimized, thereby reducing the operating costs associated with the operation of the facility, and stably operating the system by identifying the membrane wetting phenomenon of the hydrophobic separator 45 due to long-term operation. I want to.

For this, first, prior to supplying the influent to the influent chamber 41, the pretreatment unit 20 is disposed behind the raw water storage tank 10 to remove foreign substances contained in the raw water, or to the front of the raw water storage tank 10. By disposing the pretreatment unit 20, foreign substances contained in raw water supplied to the raw water storage tank 10 can be removed.

Then, the initial ammonia concentration (C _o ) and temperature and pH of the influent water stored in the flow rate adjustment tank 30 and supplied to the influent chamber 41 of the membrane contactor 40 are measured, and stored in the absorption solution storage tank 50 Measures the temperature and pH of the absorption solution supplied to the absorption solution chamber 43 of the membrane contactor 40, and supplies it to the influent chamber 41 of the membrane contactor 40 in consideration of the maximum processing capacity of the membrane contactor 40 The flow rate of the incoming water and the flow rate of the absorption solution supplied to the absorption solution chamber 43 are determined (S100).

On the other hand, prior to removing the ammonia contained in the influent using the membrane contactor 40, the initial ammonia concentration (C) of the influent that is first stored in the flow rate storage tank 30 and supplied to the influent chamber 41 of the membrane contactor 40 It is determined whether _o ) is less than or equal to the set value C _f (S200).

When the initial ammonia concentration (C _o ) is less than or equal to the set value (C _f ), the inflow water stored in the flow rate storage tank 30 is discharged to the outside.

On the other hand, when the initial ammonia concentration (C _o ) is greater than the set value (C _f ), a process of removing ammonia contained in the influent is performed using the membrane contactor 40.

The ammonia contained in the influent is removed using the hydrophobic separation membrane 45 by supplying the influent and the absorption solutions to the influent chamber 41 and the absorption solution chamber 43 of the membrane contactor 40, respectively. The discharged treated water is circulated and re-supplied to the influent chamber 41, and the absorbed solution discharged from the absorbing solution chamber 43 is circulated and re-supplied to the absorbing solution chamber 43.

That is, the inflow water stored in the flow adjustment tank 30 is supplied to the inflow chamber 41 and the treated water discharged from the inflow chamber 41 is supplied to the flow adjustment tank 30 and stored again, and then circulated back to the inflow chamber 41 After supplying, the absorbing solution stored in the absorbing solution storage tank 50 is supplied to the absorbing solution chamber 43 and the absorbing solution discharged from the absorbing solution chamber 43 is supplied back to the absorbing solution storage tank 50 and stored again. The ammonia contained in the influent water is removed using the hydrophobic separator 45 accommodated in the membrane contactor 40 by being supplied to the absorption solution chamber 43 in circulation.

In addition, when the inflow water is circulatedly supplied between the flow adjustment tank 30 and the inflow chamber 41, the heat exchanger is used to control the temperature of the inflow water to be kept constant, and the flow adjustment tank 30 is provided with a base chemical such as sodium hydroxide. Mixing is performed to control the pH of the influent to be kept constant.

In addition, when the inflow water is circulatedly supplied between the absorption solution storage tank 50 and the absorption solution chamber 43, the temperature of the absorption solution is controlled to be kept constant by using a heat exchanger, and acids such as sulfuric acid are added to the absorption solution storage tank 50. Mixing of series chemicals is controlled so that the pH of the absorption solution is kept constant.

Then, the ammonia concentration (C _ini ) of the treated water discharged from the influent chamber 41 after a predetermined period of time is measured (S300). The ammonia concentration C _ini of the treated water can be determined by measuring the ammonia concentration of the influent water stored in the flow rate adjustment tank 30 after passing through the membrane contactor 40.

Here, the predetermined time refers to the minimum time to ensure the reliability of the initial mass transfer coefficient (k _{m_ini} ) to be calculated from the ammonia concentration (C _ini ) of the treated water measured in the operating system, which is the initial mass transfer coefficient (k _{m_ini} ) To determine the initial expected arrival time (t _{f_ini} ) and the reliability of the film wetting process. In order to calculate a reliable initial mass transfer coefficient (k _{m_ini} ), the initial ammonia concentration (C _o ) and the ammonia concentration (C _ini ) to be measured after a certain time must be sufficiently distinguishable, so a predetermined time is 1 batch (flow adjustment tank ( 30) A series of processes necessary to treat the ammonia contained in the raw water stored in) It is desirable to be around 15-30% of the expected operating time. The predetermined time in this embodiment means 30 minutes after the system is started, but may vary depending on the characteristics of the system, the characteristics of the ammonia concentration detection device, the properties of the influent water, and the characteristics of the hydrophobic separator.

Then, it is determined whether the ammonia concentration C _ini of the treated water is equal to or less than the set value C _f (S400). When the ammonia concentration C _ini of the treated water is equal to or less than the set value C _f , the treated water stored in the flow rate storage tank 30 is discharged to the outside through the membrane contactor 40.

On the other hand, when the ammonia concentration (C _ini ) of the treated water is greater than the set value (C _f ), the initial mass transfer coefficient (k _{m_ini} ) of the hydrophobic separator 45 is calculated from the ammonia concentration (C _ini ) of the treated water ( S500). The initial mass transfer coefficient (k _{m_ini} ) is the initial ammonia concentration (C _o ) of the influent and the ammonia concentration (C _ini ) of the treated water discharged from the influent chamber (41) in equations (1) and (2) mentioned above. It can be calculated by substituting the surface area A of the hydrophobic separator 45, the volume V _o of the influent chamber 41, and the free ammonia fraction FA in the influent.

Then, it is determined whether the hydrophobic separator 45 is contaminated according to the wetting phenomenon from the calculated initial mass transfer coefficient (k _{m_ini} ) (S600). In addition, the control unit stops the alarm or system operation according to the degree of contamination of the hydrophobic separator 45.

Specifically, as illustrated in FIG. 3, it is determined whether or not the calculated initial mass transfer coefficient (k _{m_ini} ) is less than or equal to the shutdown mass transfer coefficient (k _{m_3} ), where the hydrophobic separation membrane 45 is completely wetted and should be stopped. (S610). When the initial mass transfer coefficient (k _{m_ini} ) is less than or equal to the shutdown mass transfer coefficient (k _{m_3} ), the system is stopped (S620).

On the other hand, if the initial mass transfer coefficient (k _{m_ini} ) is greater than the shutdown mass transfer coefficient (k _{m_3} ), the initial mass transfer coefficient (k _{m_ini} ) is a _limitable mass transfer that can be handled when the maximum contamination load of the hydrophobic separation membrane 45 is introduced. It is determined whether the coefficient (k _{m_2} ) or less (S630). Initial mass transfer coefficient (k _{m_ini)} limits the mass transfer coefficient (k _{m_2)} to thereby the hydrophobic membrane (45) is generating an alarm informing that it has reached the limit efficiency reached its limit or less (S640).

On the other hand, when the initial mass transfer coefficient (k _{m_ini)} greater than the limit, the mass transfer coefficient (k _{m_2),} initial mass transfer coefficient (k _{m_ini)} the use of a hydrophobic membrane (45) before the mass transfer coefficient (k _{m_o)} and It is determined whether or not it is less than or equal to the median (k _{m_1} ) between the limiting mass transfer coefficients (k _{m_2} ) (S650). When the initial mass transfer coefficient (k _{m_ini} ) is less than or equal to the median value (k _{m_1} ), a washing recommendation alarm is generated informing that the hydrophobic separator 45 should be cleaned (S660). On the other hand, if the initial mass transfer coefficient (k _{m_ini} ) is greater than the median value (k _{m_1} ), no alarm is generated.

As such, according to the degree of contamination of the hydrophobic separator 45, a system operation interruption and a limit efficiency reaching alarm and a washing recommendation alarm are generated. Therefore, it is possible to grasp the film wetting phenomenon of the hydrophobic separator 45 from the mass transfer coefficient of the hydrophobic separator 45, so that the system can be stably operated in response to the film wetting phenomenon of the hydrophobic separator 45.

And after grasping the degree of contamination of the hydrophobic separator 45, the initial estimate of the ammonia concentration of the treated water discharged from the influent chamber 41 from the calculated initial mass transfer coefficient (k _{m_ini} ) is reached to reach the set value (C _f ) The arrival time t _{f_ini} is calculated (S700).

Initial estimated reaching time (t _{f_ini)} will be assumed that the mass transfer coefficient (k _{m_ini)} the mass transfer coefficient (k _{m_f)} of the hydrophobic membrane (45) in the expected time of arrival (t _{f_ini)} calculation of the hydrophobic membrane (45) At this time, in equation (1), the initial ammonia concentration (C _o ) of the influent water and the set value (C _f ) of the ammonia concentration of the treated water discharged from the influent chamber 41 and the initial mass transfer coefficient (k) of the hydrophobic separator 45 _{m_ini} ) and the hydrophobic membrane 45, the surface area A, the volume V _o of the influent chamber 41, and the free ammonia fraction FA in the influent can be calculated by substituting it.

Then, the circulating influent flows between the flow adjustment tank 30 and the inflow chamber 41 until the initial estimated arrival time t _{f_ini} is reached, and the absorption liquid circulated between the absorption liquid storage tank 50 and the absorption liquid chamber 43. Ammonia contained in the influent is removed.

Then, the ammonia concentration (C _t1 ) of the treated water discharged from the influent chamber 41 is _measured at the initial estimated arrival time (t _{f_ini} ) (S800).

Then, it is determined whether the ammonia concentration C _t1 of the treated water discharged from the influent chamber 41 is equal to or less than the set value C _f (S900). When the ammonia concentration (C _t1 ) of the treated water discharged from the influent chamber 41 at the initial estimated arrival time (t _{f_ini} ) is less than or equal to the set value (C _f ), it is stored in the flow storage tank 30 through the membrane contactor 40. Discharge the treated water to the outside.

On the other hand, when the ammonia concentration (C _t1 ) of the treated water discharged from the influent chamber 41 in the initial estimated arrival time (t _{f_ini} ) is greater than the set value (C _f ), it is measured at the initial expected arrival time (t _{f_ini} ). The mass transfer coefficient (k _{m_t1} ) of the hydrophobic separation membrane 45 is recalculated from the ammonia concentration (C _t1 ) of the treated water discharged from the influent chamber 41 (S1000).

The recalculated mass transfer coefficient (k _{m_t1} ) is the initial ammonia concentration (C _o ) of the influent and the ammonia concentration (C _t1 ) of the treated water discharged from the influent chamber (41) in equations (1) and (2) mentioned above. ) Can be calculated by substituting the surface area A of the hydrophobic membrane 45, the volume V _o of the influent chamber 41, and the free ammonia fraction FA in the influent.

Then, it is determined whether or not the hydrophobic separation membrane 45 is contaminated according to the wetting phenomenon from the _recalculated material transfer coefficient (k _{m_t1} ) (S1100). In addition, the control unit stops the alarm or system operation according to the degree of contamination of the hydrophobic separator 45.

As specifically shown in Figure 4, the material of the mass transfer coefficient calculated (k _{m_t1)} a hydrophobic membrane (45) is fully film wetting determines whether or less shut down the mass transfer coefficient (k _{m_3)} to cease the operation (S1110). When the recalculated mass transfer coefficient (k _{m_t1} ) is less than or equal to the shutdown mass transfer coefficient (k _{m_3} ), the system is stopped (S1120).

On the other hand, the re-calculated mass transfer coefficient (k _{m_t1)} shuts down the mass transfer coefficient processed with maximum pollution load inlet of the case is greater than (k _{m_3),} the re-calculated mass transfer coefficient (k _{m_t1)} a hydrophobic membrane (45) It is determined whether or not the possible limit mass transfer coefficient (k _{m_2} ) or less (S1130). Generates an indicating material hayeoteum hydrophobic membrane (45) it reaches the limit, if not more than the calculated mass transfer coefficient (k _{m_t1)} limits the mass transfer coefficient (k _{m_2)} alarm limits efficiency reached (S1140).

On the other hand, re-calculating the mass transfer coefficient (k _{m_t1)} limits the mass transfer coefficient (k _{m_2)} using precursors of the to greater than, the re-calculated mass transfer coefficient (k _{m_t1)} hydrophobic membrane 45, the transmission coefficient ( _{m_o} k) and limits the mass transfer coefficient (it is determined whether or not more than the median (k _{m_1)} between _{m_2} k) (S1150). When the recalculated material transfer coefficient (k _{m_t1} ) is less than or equal to the median (k _{m_1} ), a washing recommendation alarm is generated informing that the hydrophobic separator 45 should be cleaned (S1160). On the other hand, if the recalculated mass transfer coefficient (k _{m_t1} ) is greater than the median value (k _{m_1} ), no alarm is generated.

As such, according to the degree of contamination of the hydrophobic separator 45, a system operation interruption and a limit efficiency reaching alarm and a washing recommendation alarm are generated. Therefore, it is possible to grasp the film wetting phenomenon of the hydrophobic separator 45 from the mass transfer coefficient of the hydrophobic separator 45, so that the system can be stably operated in response to the film wetting phenomenon of the hydrophobic separator 45.

Then, after grasping the degree of contamination of the hydrophobic separation membrane 45, it is expected to reach the ammonia concentration of the treated water discharged from the influent chamber 41 from the _recalculated mass transfer coefficient (k _{m_t1} ) to reach the set value (C _f ). The time t _{f_t1} is recalculated (S1200).

Estimated arrival time (t _{f_t1)} will be assumed that the mass transfer coefficient (k _{m_f)} of the hydrophobic membrane (45) in the mass transfer coefficient (k _{m_t1)} the estimated arrival time (t _{f_t1)} recalculated in the hydrophobic membrane (45) At this time, in equation (1), the initial ammonia concentration (C _o ) of the influent water and the set value (C _f ) of the ammonia concentration of the treated water discharged from the influent chamber 41 and the recalculated mass transfer coefficient of the hydrophobic separator 45 It can be calculated by substituting (k _{m_t1} ), the surface area A of the hydrophobic separator 45, the volume V _o of the influent chamber 41, and the free ammonia fraction FA in the influent.

Then, the inflow water is circulated between the flow rate adjustment tank 30 and the inflow chamber 41 until the expected arrival time t _{f_t1} is reached, and the absorption solution is circulated between the absorption solution storage tank 50 and the absorption solution chamber 43. Ammonia contained in is removed.

Then, the ammonia concentration C _t2 of the treated water discharged from the influent chamber 41 is _measured at the expected arrival time t _{f_t1} (S1300).

Then, it is determined whether the ammonia concentration C _t2 of the treated water discharged from the influent chamber 41 is equal to or less than the set value C _f (S1400). When the ammonia concentration (C _t2 ) of the treated water discharged from the influent chamber 41 at the expected arrival time (t _{f_t1} ) is less than or equal to the set value (C _f ), the treatment stored in the flow reservoir 30 through the membrane contactor 40 Discharge the water to the outside.

On the other hand, if the ammonia concentration (C _t2 ) of the treated water discharged from the influent chamber 41 at the estimated recalculated arrival time (t _{f_t1} ) is greater than the set value (C _f ), the above-described operations of S1000 to S1400 are repeated. To remove ammonia contained in the treated water.

Specifically, ammonia of the treated water discharged from the influent chamber 41 measured at the estimated arrival time t _{f_t1} recalculated by recirculating the treated water discharged from the influent chamber 41 and resupplying it to the influent chamber 41 The mass transfer coefficient (k _{m_t2} ) of the hydrophobic separator 45 is recalculated from the concentration (C _t2 ) (S1000).

Then, it is determined whether or not the hydrophobic separation membrane 45 is contaminated according to the wetting phenomenon from the _recalculated material transfer coefficient (k _{m_t2} ) (S1100). As shown in FIG. 4, the control unit stops the alarm or system operation according to the degree of contamination of the hydrophobic separator 45.

Then, after grasping the degree of contamination of the hydrophobic separator 45, the expected reach of the ammonia concentration of the treated water discharged from the influent chamber 41 from the _recalculated mass transfer coefficient (k _{m_t2} ) reaches the set value (C _f ) The time t _{f_t2} is recalculated (S1200).

Then, the influent is circulated between the flow adjustment tank 30 and the influent chamber 41 until the expected arrival time t _{f_t2} is reached, and the absorption solution is circulated between the absorption solution storage tank 50 and the absorption solution chamber 43 to influent water. Ammonia contained in is removed.

Then, the ammonia concentration C _t3 of the treated water discharged from the influent chamber 41 is _measured at the expected arrival time t _{f_t2} (S1300).

Then, it is determined whether the ammonia concentration C _t3 of the treated water discharged from the influent chamber 41 is equal to or less than the set value C _f (S1400). When the ammonia concentration (C _t3 ) of the treated water discharged from the influent chamber 41 at the expected arrival time (t _{f_t2} ) is equal to or less than the set value (C _f ), the treatment stored in the flow reservoir 30 through the membrane contactor 40 Discharge the water to the outside.

As described above, this embodiment removes ammonia contained in the treated water by repeating the above-described operations of S1000 to S1400, thereby minimizing equipment operation in the operation of the ammonia removal system 100, thereby reducing operating costs. .

As described above, the present invention is not limited to the described embodiments, and it is obvious to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the present invention. Therefore, such modifications or variations will have to belong to the claims of the present invention.

100: ammonia removal system 10: raw water storage tank
20: pre-treatment unit 30: flow adjustment tank
40: membrane contactor 41: influent chamber
43: absorption solution chamber 45: hydrophobic separator
50: absorption solution storage tank 60: compound storage tank

Claims (9)

(A) when the initial ammonia concentration of the inlet water stored in the flow rate storage tank and supplied to the membrane contactor is less than a set value, discharging the inflow water stored in the flow rate storage tank to the outside;
(b) When the initial ammonia concentration is greater than the set value, the ammonia contained in the influent is removed by using a hydrophobic separation membrane in the membrane contactor by circulating the influent and the absorption solution to the membrane contactor, but after a predetermined time has elapsed Measuring the ammonia concentration of the treated water discharged from the apparatus and discharging the treated water to the outside when the ammonia concentration of the treated water is equal to or less than a set value;
(c) calculating an initial mass transfer coefficient of the hydrophobic separation membrane from the ammonia concentration of the treated water when the ammonia concentration of the treated water measured after a predetermined period of time is greater than a set value;
(d) calculating an initial estimated arrival time for the ammonia concentration of the treated water discharged from the membrane contactor from the calculated initial mass transfer coefficient to reach a set value; And
(E) control method of the ammonia removal system comprising the step of discharging the treated water to the outside when the ammonia concentration of the treated water discharged from the membrane contactor at the calculated initial estimated arrival time is less than or equal to a set value. According to claim 1,
Step (c) is,
(c-1) Ammonia removal further comprising the step of determining whether the hydrophobic separation membrane is contaminated according to the membrane wetting phenomenon from the calculated initial mass transfer coefficient, and stopping the alarm or system operation according to the degree of contamination of the hydrophobic separation membrane. How to control the system. According to claim 2,
Step (c-1) is,
Stopping the operation of the system when the calculated initial mass transfer coefficient is equal to or less than the shutdown mass transfer coefficient of the hydrophobic separator;
Generating a threshold efficiency reaching alarm indicating that the hydrophobic separator has reached a limit when the calculated initial mass transfer coefficient is equal to or less than the threshold mass transfer coefficient of the hydrophobic separator; And
Ammonia removal comprising the step of generating a washing recommendation alarm informing that the hydrophobic separator should be cleaned when the calculated initial mass transfer coefficient is equal to or less than an intermediate value between the mass transfer coefficient and the limit mass transfer coefficient before use of the hydrophobic separator. How to control the system. According to claim 1,
(f) When the ammonia concentration of the treated water discharged from the membrane contactor is greater than a set value at the calculated initial expected arrival time, the hydrophobicity is calculated from the ammonia concentration of the treated water discharged from the membrane contactor at the initial expected arrival time. Recalculating the mass transfer coefficient of the separator;
(g) recalculating the estimated arrival time for the ammonia concentration of the treated water discharged from the membrane contactor from the recalculated mass transfer coefficient to reach a set value; And
(h) The control method of the ammonia removal system further comprising the step of discharging the treated water to the outside when the ammonia concentration of the treated water discharged from the membrane contactor is equal to or less than a set value at the estimated re-calculated arrival time. The method of claim 4,
Step (f) is,
(f-1) Ammonia removal further comprising the step of determining whether the hydrophobic separation membrane is contaminated according to the film wetting phenomenon from the recalculated material transfer coefficient, and stopping the alarm or system operation according to the degree of contamination of the hydrophobic separation membrane. How to control the system. The method of claim 5,
Step (f-1) is,
Stopping the system operation when the recalculated mass transfer coefficient is equal to or less than the shutdown mass transfer coefficient of the hydrophobic separator;
Generating a limit efficiency reaching alarm informing that the hydrophobic separator has reached a limit when the recalculated material transfer coefficient is equal to or less than the limit material transfer coefficient of the hydrophobic separator; And
And removing the ammonia comprising the step of generating a cleaning recommendation alarm indicating that the hydrophobic separation membrane should be cleaned when the recalculated mass transfer coefficient is equal to or lower than an intermediate value between the mass transfer coefficient and the limit mass transfer coefficient before use of the hydrophobic separation membrane. How to control the system. According to claim 1,
(a-1) The control method of the ammonia removal system further comprising a pre-treatment step of removing foreign substances contained in the inflow water supplied to the membrane contactor before the step (a). According to claim 1,
(a-1) The control method of the ammonia removal system further comprising the step of constantly adjusting the temperature and pH of the influent water supplied to the membrane contactor before the step (a). According to claim 1,
(a-2) The control method of the ammonia removal system further comprising the step of constantly adjusting the temperature and pH of the absorption solution supplied to the membrane contactor in the step (a).

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