CN103663820B - Air flotation membrane filtration purification system and control method thereof - Google Patents

Abstract

The invention discloses a water treatment structure relating to a water purification plant, in particular to an air-floating membrane filtration purification system; the air-flotation membrane filtration purification system is divided into a water inlet buffer area, a water distribution area, an air-flotation contact area and an air-flotation separation and membrane filtration water outlet area, a micro-bubble generating device is connected with a dissolved air water conveying pipeline and arranged in the air-flotation contact area, the air-flotation separation area and membrane filtration water outlet area is provided with a conical hopper, a supporting beam and an immersed membrane assembly from bottom to top, a residue scraping machine travels on a track arranged on the side wall of the tank, and a residue discharging groove is arranged on the side wall opposite to a water inlet of the tank; the invention has the advantages of organically combining the air flotation and ultrafiltration membrane filtration processes, being capable of treating low turbid or high algae-laden water, small occupied area, simple structure, low civil engineering cost, high load resistance, low self-water consumption rate, low operation cost and simple automatic control.

Description

Air flotation membrane filtration purification system and control method thereof

technical field

The invention relates to a water quality treatment device for a water purification treatment plant and a reclaimed water reuse plant, and in particular provides an air flotation membrane filtration purification system.

Background technique

At present, when the turbidity of the water source of the water purification plant is low or the algae is high, the technology of air flotation and filtration is often used. Existing water plants often build separate air flotation tanks, using the partial reflux dissolved air flotation method. The bottom of the air flotation separation zone of the air flotation tank is equipped with a perforated water collection pipe to collect water, and the upper part is an empty tank, which is a serious waste of space. The filtration process after air flotation often adopts sand filter or ultrafiltration membrane filtration. The civil structure of the sand filter is relatively complex and occupies a large area. The filter must be backwashed regularly, which consumes a lot of water and high operating costs. As a new type of technology, ultrafiltration membrane water purification treatment technology is more and more widely used in the field of water treatment, and can directly replace sand filters as the final treatment system. The traditional ultrafiltration membrane filtration technology has too many pipelines and valves, complicated control, troublesome maintenance, easy leakage of the system, and a large footprint. Now the submerged membrane filtration technology is gradually developed and applied. The ultrafiltration membrane is made into several components and placed in a pool, but there is a small load resistance capacity. High disadvantage.

Contents of the invention

Aiming at the above technical problems, the present invention proposes an air flotation membrane filter for treating low-turbidity or high-algae water with small footprint, simple structure, low civil construction cost, high load resistance capacity, low self-water rate, and simple control. purification system.

In order to achieve the above purpose, it is realized through the following technical solutions:

The air flotation membrane filtration purification system includes: the filter tank body surrounded by the outer wall, the dissolved air flotation device and the submerged membrane filter device installed inside the filter tank body;

The interior of the filter body is divided into water inlet buffer zone, water inlet water distribution area, air flotation contact area, air flotation separation area and membrane filter water outlet area by the partition wall;

The middle interval between the inlet buffer zone and the inlet water distribution area is the inlet water distribution weir;

The outer wall of the filter body is provided with a water inlet pipe for communicating with the water inlet buffer zone;

The water inlet distribution area and the air flotation contact area are connected through the water inlet distribution hole arranged in the partition wall between the water inlet water distribution area and the air flotation contact area;

The dissolved air flotation device includes: a dissolved air pump or a dissolved air tank for outputting dissolved air water, a dissolved air water delivery pipeline for guiding dissolved air water, and a microbubble generating device for generating microbubbles;

The dissolved air water delivery pipeline is fixed on the partition wall processed with water inlet and distribution holes, and one end is fixed to the output end of the dissolved air pump or dissolved air tank, and the other end extends into the air flotation contact area;

The micro-bubble generating device is fixed on the dissolved air water delivery pipeline and extends into the end of the air flotation contact area;

The air flotation separation area of the filter body and the membrane filtration water outlet area are processed with a number of conical mud buckets with a downwardly convex cross section; the lower end of the conical mud bucket is provided with a mud discharge pipe;

The submerged membrane filtration device includes: the submerged membrane module, the submerged membrane outlet main pipe and the submerged membrane backwash inlet main pipe arranged in the air flotation separation area of the filter body and the membrane filtration water outlet area through a stainless steel frame;

The submerged membrane outlet main pipe is also used as the submerged membrane water inlet main pipe, and one end is connected with each submerged membrane outlet branch pipe of the submerged membrane module, and the other end is connected with the suction pump;

One end of the submerged membrane backwash inlet main pipe is connected to each submerged membrane backwash inlet branch pipe of the submerged membrane module, and the other end is connected to the blower;

The main body of the filter tank is provided with a chemical washing main pipe that communicates with each submerged membrane outlet branch pipe of the submerged membrane module through pipelines;

The upper end of the filter tank body is provided with a scum scraping mechanism for scraping off surface scum;

The filter tank body is located at the end of the stroke of the slag-scraping walking mechanism, and a slag discharge groove is arranged;

The connection between the slag discharge tank and the air flotation separation area and membrane filtration water area is separated by a slag discharge weir;

The air flotation separation area of the filter body and the membrane filtration water outlet area are equipped with support beams for strengthening the stainless steel frame of the submerged membrane module;

The slag-scraping walking mechanism is assembled on the track arranged on the side wall of the filter tank body and driven by a motor; the slag discharge tank is set at the opposite end of the filter tank body water inlet;

The slag discharge tank is provided with a flushing water pipe for flushing the slag discharge tank;

As a preference, the submerged membrane module adopts ultrafiltration membrane or microporous filtration membrane according to the requirements of effluent water quality;

As a preference, the submerged membrane module injects sodium hypochlorite solution through the chemical washing main pipe for chemical washing;

As a preference, the submerged water depth of the submerged membrane module is 1-2 meters;

As a preference, each mud discharge pipe is connected in series, and an automatic control valve and a manual valve are installed on the mud discharge pipe;

When the amount of treated water is large, the filter body is a concrete pouring structure; when the amount of treated water is small, the filter body is made into a small water purification treatment equipment with a shell made of metal or plastic;

The present invention adopting the above-mentioned technical solution needs to assemble a control cabinet in advance, and the control cabinet is provided with a programmable logic controller (abbreviated as PLC) to complete the storage and execution of the fixed program, and is assembled on the surface of the control cabinet for manual setting of parameters and operation Human-machine interface HMI;

The control method of the air flotation membrane filtration purification system comprises the following steps:

Step 1. During the co-injection of filtered water and dissolved air water, detect the water level in the air flotation separation area and the membrane filtration water outlet area, and when the water level reaches the specified height, start the submerged membrane water outlet main pipe outlet pump to discharge the filtered water;

Before the above operation steps, it is necessary to assemble the water inlet electric control valve on the water inlet pipe, the outlet end of the submerged membrane outlet main pipe is connected with the rotor pump, and the liquid level gauge is set to monitor the water level in the air flotation separation area and the membrane filtration water outlet area, and enter Water electric control valves, rotor pumps and liquid level gauges are all connected to the control cabinet through circuits;

Dissolved air water intake can be realized through some equipment such as automatic air compressor and return pump, and this part of equipment can also be completely realized through a dissolved air pump equipment, and all of them are connected to the control cabinet through the circuit;

For specific control, firstly, the human-machine interface HMI sets the liquid level gauge to monitor the specified liquid level height. When the liquid level height is lower than the specified liquid level height, the liquid level gauge sends a low liquid level signal to the programmable logic controller (PLC for short). Compare, and then issue a low liquid level execution command to control the dissolved air water inlet equipment and the water inlet electric control valve to inject dissolved air water and water to be filtered. When the liquid level gauge monitors the liquid level to reach the specified height, the liquid level The meter sends a normal working signal to the programmable logic controller (abbreviated as PLC) for comparison and then sends out a normal operation execution command to control the dissolved air water inlet equipment and water inlet electric control valve to control the total injection volume of dissolved air water and water to be filtered , and at the same time control and start the rotor pump to suck out the filtered water, the overall liquid level is monitored in real time by the liquid level gauge, and controlled and regulated by the programmable logic controller (PLC for short);

Step 2, slag discharge. After the air flotation membrane filtration purification system has been running for a certain period of time, scrape and drain the surface scum of the filter tank of the air flotation membrane filtration purification system; The surface liquid level of the filter tank of the floating membrane filtration purification system is high, and then the scraping mechanism is started to scrape the slag; the scum is scraped and discharged into the slag discharge tank, and then washed and discharged through the flushing water pipe; after the slag discharge process is completed, the air flotation membrane filtration purification system resume normal operation;

The slag-scraping walking mechanism can be that the rollers of the traveling trolley are directly driven by the motor to walk on the track arranged on the side wall of the filter tank body, and the motor and the control cabinet are connected through a circuit;

Slag discharge is a timing execution process, and the length of timing is determined by the formation rate of dross on the entire liquid surface. First, a scraping timer is set inside the control cabinet, and a timing value is set through the man-machine interface HMI. When the timing value is reached, the scraping time is reached. The slag timer sends a slag scraping signal to the programmable logic controller (referred to as PLC), and then the programmable controller (abbreviated as PLC) simultaneously outputs control to increase the total injection volume of dissolved air water and water to be filtered, and reduce the water output to improve Then control and start the slag scraping mechanism to drive the motor. When the slag scraping mechanism reaches the slag discharge end of the air flotation separation area and membrane filtration water outlet area, it is necessary to unfold the slag discharge plate at the lower end of the slag scraping mechanism at a certain angle, and then continue The slag is discharged by walking, and the slag is scraped and discharged into the slag discharge tank, and then washed and discharged through the flushing water pipe; after the slag discharge is completed, the programmable logic controller (PLC) controls the total injection volume and water output of dissolved air water and filtered water, The liquid level is generally restored, and the system continues to operate normally;

Step 3, mud discharge, after the air flotation membrane filtration purification system has been running for a certain period of time, the sediment deposited in the cone-shaped mud bucket by the air flotation membrane filtration purification system is then discharged through the mud discharge pipe, and the air flotation membrane filtration purification system The mud discharge frequency is determined by the deposition rate of the air flotation membrane filtration purification system;

The mud discharge is also a timing process, and the timing length is determined by the sludge formation rate of the cone-shaped mud bucket at the bottom of the filter body;

There are two kinds of mud discharge control: one is to manually control the discharge through the manual valve installed on the mud discharge pipe, or set a mud discharge timer inside the control cabinet, and set a timing value through the man-machine interface HMI. When the time is set, the mud discharge timer sends a mud discharge signal to the programmable logic controller (abbreviated as PLC), and then the programmable logic controller (abbreviated as PLC) outputs to control the opening of the automatic control valve on the mud discharge pipe to realize the mud discharge operation; The sludge discharge operation does not affect the operation of the filtration program;

Step 4, the backwashing process, the submerged membrane module needs to be backwashed after running for a period of time. During backwashing, the rotor pump at the outlet of the submerged membrane outlet main pipe will pump clean water into the submerged membrane, and will adhere to the pores and surface of the membrane. In order to ensure the effect of backwashing, the air blower connected to the submerged membrane backwashing intake main pipe is also used for air washing during water washing. After backwashing and standing still for a period of time, the pollutants in the water are deposited In the conical mud hopper at the bottom of the filter, it is discharged out of the pool through the mud discharge pipe. It is realized through the automatic control valve of the mud discharge pipe, which can be controlled remotely. The manual valve can be used when the automatic control valve needs to be overhauled. The submerged membrane module Medicine washing is also required every certain period. Medicine washing is to inject sodium hypochlorite solution into the submerged membrane outlet branch pipe through the medicine washing main pipe and distribute it to each submerged membrane module. After the medicine washing is completed, all the water in the pool is drained through the mud discharge pipe.

While the control cabinet completes the above control process, it monitors in real time, records the status of each electric equipment in the control cabinet at all times, and promptly controls the pre-configured sound and light alarm device to alarm in case of abnormality.

In summary, the present invention has the following advantages compared with traditional techniques:

First, the air flotation membrane filtration purification system organically combines the air flotation process and the membrane filtration process, and the air flotation separation and membrane filtration are completed in the same pool, which makes full use of the space in the separation area of the air flotation pool, and does not need to build another pool, saving the occupied area. Land area and cost; taking a 10,000-ton water plant with the same treatment capacity as an example, if the traditional air flotation and sand filter process is designed, the air flotation outlet is connected to the sand filter, and the design filtration rate is 7m/h, the net filtration area needs 60 square meters, plus the water inlet and outlet areas and structural walls before and after the sand filter, it is necessary to add at least about 100 square meters to the area of the air flotation membrane filter to build the filter; if the traditional air flotation plus super Membrane process design, using an ultrafiltration membrane with an outer diameter of 160mm, a single water production rate of 1t/h requires 670 membranes. The arrangement of these membranes and supporting pipelines requires an area based on the air flotation membrane filtration purification system. Increase the area by at least about 200 square meters.

Second, the air flotation membrane filtration purification system uses air flotation separation as the pretreatment of the membrane filtration treatment, which can improve the load resistance of the membrane filtration treatment, and at the same time, the microbubbles generated by the air flotation can frictionally clean the surface of the membrane filaments of the submerged membrane module The function can improve the anti-pollution of the membrane, and in turn, membrane filtration can replace the traditional water collection tank or perforated pipe water collection and discharge method of air flotation, and can greatly improve the effluent water quality of air flotation treatment; the air flotation membrane filtration purification system Membrane modules have high filtration precision and can ensure that the turbidity of the final effluent is below 0.2NTU. However, with the increase of the filtration time of the sand filter, if the backwashing is not timely, it is easy to have filter penetration, and the turbidity of the effluent cannot be guaranteed to be below 1NTU. , The effluent quality of the air flotation membrane filtration purification system is obviously better than that of the sand filter.

Thirdly, the air flotation membrane filtration purification system sets multiple conical mud hoppers at the bottom of the pool. The mud discharge pipe of the bucket is discharged out of the pool, without draining the water of the entire pool, which reduces the self-water rate of the water plant; fourth, the backwash cycle of the air flotation membrane filtration purification system is short, the time is short, and the water consumption is small. For a 10,000-ton water plant with the same processing capacity, the backwashing time of the air flotation membrane filtration purification system is one-tenth of that of the sand filter, the water consumption is one-seventh of the sand filter, and the backwashing cycle is shorter than that of the ultrafiltration membrane. The period is more than doubled.

Fifth, the membrane components of the air flotation membrane filtration purification system are easy to install and easy to maintain. For a 10,000-ton water plant with the same treatment capacity, the construction period is about 5 days shorter than that of ultrafiltration membranes, and the installation materials are 20% less than that of ultrafiltration membranes.

Sixth, the air flotation membrane filtration purification system only needs one pump to realize the functions of water production and backwashing, while the ultrafiltration membrane needs two pumps to realize it.

Seventh, the control device of the air flotation membrane filtration purification system automatically completes the process automatic operation of the air flotation membrane filtration purification system, which greatly reduces human operations and improves labor productivity.

The invention simplifies the production and management process of the air flotation filtration process, saves the occupied area, reduces the investment and operating expenses, and saves the cost.

The above description is only an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, it can be implemented according to the contents of the description, and in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable , the following preferred embodiments are specifically cited below, and are described in detail as follows in conjunction with the accompanying drawings.

Description of drawings

The present invention has 4 drawings in total, wherein:

Fig. 1 is a schematic view of the upper transverse cross-sectional structure of the present invention.

Fig. 2 is a schematic view of the lower transverse cross-sectional structure of the present invention.

Fig. 3 is a schematic diagram of a longitudinal section structure at the position of Fig. 1A-A.

Fig. 4 is a schematic diagram of the air flotation membrane filtration purification system and its control system of the present invention.

Detailed ways

The air flotation membrane filtration purification system shown in Fig. 1, Fig. 2, Fig. 3 and Fig. 4 includes: a filter tank body 27 surrounded by an outer wall, a dissolved air flotation device 28 and a filter tank body 27 inside The submerged membrane filtration device 29;

The interior of the filter body 27 is divided into a water inlet buffer zone 2, a water inlet distribution area 4, an air flotation contact area 6, an air flotation separation area and a membrane filtration water output area 7 by a partition wall;

The middle interval between the inlet buffer zone 2 and the inlet water distribution area 4 is the inlet water distribution weir 3;

The outer wall of the filter tank body 27 is provided with a water inlet pipe 1 for communicating with the water inlet buffer zone 2;

The water inlet distribution area 4 communicates with the air flotation contact area 6 through the water inlet distribution hole 5 arranged on the partition wall between the water inlet water distribution area 4 and the air flotation contact area 6;

The dissolved air flotation device 28 includes: a dissolved air pump or a dissolved air tank for outputting dissolved air water, a dissolved air water delivery pipeline 20 for guiding the dissolved air water and a microbubble generating device 21 for generating microbubbles;

The dissolved air water delivery pipeline 20 is fixed on the partition wall processed with the water inlet distribution hole 5, and one end is fixed to the output end of the dissolved air pump or the dissolved air tank, and the other end extends into the air flotation contact area 6;

The microbubble generating device 21 is fixed on the dissolved air water delivery pipeline 20 and extends into the end of the air flotation contact zone 6;

The air flotation separation area of the filter body 27 and the membrane filtration water outlet area 7 are processed with several conical mud buckets 22 with downwardly convex cross-sections; the lower end of the conical mud buckets 22 is provided with a mud discharge pipe 23;

The submerged membrane filtration device 29 includes: the submerged membrane module 9 arranged in the air flotation separation area of the filter body 27 and the membrane filtration water outlet area 7 through the stainless steel frame 8, the submerged membrane water outlet main pipe 12 and the submerged membrane backwashing air inlet Header 13;

The submerged membrane outlet main pipe 12 also serves as the submerged membrane water inlet main pipe, and one end communicates with each submerged membrane outlet branch pipe 10 of the submerged membrane module 9, and the other end communicates with the suction pump;

One end of the submerged membrane backwash air intake main pipe 13 communicates with each submerged membrane backwash intake branch pipe 11 of the submerged membrane module 9, and the other end communicates with the blower;

The filter tank body 27 is provided with a medicine washing main pipe 15 that communicates with each submerged membrane outlet branch pipe 10 of the submerged membrane module 9 through pipelines;

The upper end of the filter tank body 27 is provided with a scraper walking mechanism 19 for scraping off surface scum;

The filter tank body 27 is located at the end of the stroke of the slag-scraping walking mechanism 19 and is provided with a slag discharge tank 17;

The connection between the slag discharge tank 17 and the air flotation separation zone and membrane filtration effluent zone 7 is separated by a slag discharge weir 18;

The air flotation separation area and membrane filtration water outlet area 7 of the filter body 27 is internally provided with a support beam 26 for strengthening the stainless steel frame 8 supporting the submerged membrane module 9; that is, the stainless steel frame 8 is located in the air flotation separation area and membrane filtration water outlet area Support beam 26 in 7;

The slag-scraping walking mechanism 19 is assembled on the track arranged on the side wall of the filter tank body 27 and is driven by a motor; the running plane of the slag-scraping walking mechanism 19 is parallel to the plane of the upper end of the slag discharge tank 17 and is located above the upper end of the slag discharge tank 17;

The slag discharge tank 17 is arranged at the end opposite to the water inlet of the filter tank body 27;

The slag discharge tank 17 is provided with a flushing water pipe 16 for flushing the slag discharge tank 17;

Preferably, the submerged membrane module 9 adopts an ultrafiltration membrane or a microporous filtration membrane according to the requirements of the effluent water quality;

Preferably, the submerged membrane module 9 injects a sodium hypochlorite solution through the medicine washing main pipe 15 for medicine washing;

As preferably, the submerged water depth of the submerged membrane module 9 is 1-2 meters;

As preferably, each mud discharge pipe 23 is connected in series, and an automatically controllable valve and a manual valve are installed on the mud discharge pipe 23;

When the amount of treated water is large, the filter body 27 is a concrete pouring structure, and when the amount of treated water is small, the filter body 27 is made into a small-scale water purification treatment device whose shell material is metal or plastic;

When the present invention adopting the above-mentioned technical scheme is in normal operation, the raw water (water to be filtered) enters the buffer zone 2 from the water inlet pipe 1 and then evenly enters the air flotation contact zone 6 through the water distribution area 4 and the water inlet distribution hole 5, and the dissolved air water delivery pipeline 20 transports the dissolved air water, and releases the microbubbles through the microbubble generating device 21. The microbubbles and the suspended particles in the raw water are combined in the air flotation contact zone 6 and then enter the air flotation separation zone and submerged membrane filtration zone 7, and the suspended particles Bloated by the microbubbles and gathered in the upper part of the air flotation separation zone and submerged membrane filtration zone 7, it is regularly scraped by the slag scraping mechanism 19 to the slag discharge tank 17 to be discharged, and the submerged membrane module 9 sucks the water further through the suction pump. Produced after filtering.

The utility model adopting the above-mentioned technical solution needs to assemble a control cabinet 33 in advance, and a programmable logic controller (PLC) is provided in the control cabinet 33 to complete the storage and execution of the fixed program, and is assembled on the surface of the control cabinet 33 for manual operation. Man-machine interface HMI32 for parameter setting and operation;

A method for controlling a dissolved air flotation air membrane filter system, comprising the following steps:

Step 1. During the joint injection of filtered water and dissolved air water, detect the water level in the air flotation separation zone and the membrane filtration water outlet zone 7. When the water level reaches the specified height, start the submerged membrane water outlet main pipe 12 outlet pump to realize the filtered water discharge;

Before the above operation steps, it is necessary to assemble the water inlet electric control valve on the water inlet pipe 1, the outlet end of the submerged membrane outlet main pipe 12 is connected with the rotor pump, and the liquid level gauge 30 is set to monitor the water level in the air flotation separation area and the membrane filtration water outlet area 7 height, and the water inlet electric control valve, the rotor pump and the liquid level gauge 30 are all communicated with the control cabinet 33 through the circuit;

The water inflow of dissolved air water can be realized through some equipments such as automatic air compressor and return pump, and this part of equipment can also be realized completely through a dissolved air pump equipment, and all of them are connected with the control cabinet 33 through the circuit;

Concrete control, at first the man-machine interface HMI32 sets the liquid level meter 30 to monitor the specified liquid level height, when the liquid level height is lower than the specified liquid level height, the liquid level meter 30 sends a low liquid level signal to the programmable logic controller (abbreviated as PLC ) for comparison, and then issue a low liquid level execution command to control the work of the dissolved air water inlet equipment and the water inlet electric control valve to inject dissolved air water and water to be filtered. When the liquid level gauge 30 sends a normal operation signal to the programmable logic controller (abbreviated as PLC) for comparison and then sends a normal operation execution command to control the dissolved air water inlet equipment and the water inlet electric control valve to control the dissolved air water and the water to be filtered The total injection volume is controlled, and at the same time, the rotor pump is controlled to suck out the filtered water, and the overall liquid level is monitored in real time by the liquid level gauge 30, and controlled and regulated by a programmable logic controller (abbreviated as PLC);

Step 2, slag removal, after a dissolved air flotation membrane filter system has been running for a certain period of time, scrape and discharge the scum on the surface of the filter tank of a dissolved air flotation membrane filter system; firstly, control the increase Water inflow and water outflow are reduced to raise the liquid level on the surface of a dissolved air flotation air membrane filter system, and then start the scraping slag walking mechanism 19 to scrape slag; the slag is scraped and discharged into the slag discharge tank 17, and then Rinse and discharge through the flushing water pipe 16; after the slag discharge process is completed, a dissolved air flotation air membrane filter system resumes normal operation;

The slag scraping walking mechanism 19 can be, the trolley roller is directly driven by a motor to walk on the track arranged on the side wall of the filter tank body 27, and the motor is connected with the control cabinet 33 through a circuit;

The slag discharge is a timing execution process, and the timing length is determined by the dross formation rate of the entire liquid surface. First, a slag scraping timer is set inside the control cabinet 33, and a timing value is set through the man-machine interface HMI32. When the timing value is reached The slag scraping timer sends a slag scraping signal to the programmable logic controller (abbreviated as PLC), and then the programmable logic controller (abbreviated as PLC) simultaneously outputs control to increase the total injection volume of dissolved air water and water to be filtered, and reduce the water output to improve When the liquid level is high, then control and start the slag scraping mechanism 19 to drive the motor. When the slag scraping mechanism 19 reaches the slag discharge end of the air flotation separation area and membrane filtration water outlet area 7, it is necessary to unfold the slag discharge plate 31 at the lower end of the slag scraping mechanism 19 at a certain angle, and then continue to walk for slag discharge, the scum is scraped and discharged into the slag discharge tank 17, and then rinsed and discharged through the flushing water pipe 16; after the slag discharge is completed, the programmable logic controller (abbreviated as PLC) controls the dissolved air water and The total water injection volume and water output volume will restore the liquid level as a whole, and the system will continue to operate normally;

Step 3, mud discharge, after a certain period of operation of a dissolved air flotation membrane filter system, the sediment deposited in the cone-shaped mud hopper 22 by a dissolved air flotation membrane filter system is then discharged The mud pipe 23 is discharged, and the mud discharge frequency of a dissolved air flotation membrane filter system is determined by the deposition rate of a dissolved air flotation membrane filter system;

The mud discharge is also a timing execution process, and the timing time length is determined by the sludge formation rate of the conical mud bucket 22 at the bottom of the filter tank body 27;

There are two types of mud discharge control: one is to manually control the discharge through the manual valve installed on the mud discharge pipe 23, or set a mud discharge timer inside the control cabinet 33, and set a timing value through the man-machine interface HMI32, When reaching the timing value, the mud discharge timer sends a mud discharge signal to a programmable logic controller (abbreviated as PLC), and then the programmable logic controller (abbreviated as PLC) outputs an instruction to open the automatic control valve on the control mud discharge pipe 23 to realize Sludge discharge operation; the sludge discharge operation process does not affect the operation of the filtration program.

Step 4, the backwashing process, the submerged membrane module 9 needs to be backwashed after running for a period of time. During backwashing, the rotor pump at the outlet end of the submerged membrane water outlet main pipe 12 becomes the pump that pumps clean water into the submerged membrane, and will adhere to the pores of the membrane. and the pollutants on the surface are washed down. In order to ensure the backwashing effect, the blower blowing air connected to the submerged membrane backwashing intake manifold 13 is used for air washing while washing. The sediment is deposited into the conical mud bucket at the bottom of the filter, and then discharged out of the pool through the mud discharge pipe 23, which is realized by the automatic control valve of the mud discharge pipe 23, which can be controlled remotely, and the manual valve can be used when the automatic control valve needs to be overhauled , the submerged membrane module 9 needs to be washed every certain period. The medicine washing is to inject the sodium hypochlorite solution into the submerged membrane outlet branch pipe through the medicine washing main pipe 15 and distribute it to each submerged membrane module. After the medicine washing is completed, the water in the pool is drained The mud pipes are all drained.

While completing the above control process, the control cabinet 33 monitors in real time, records the status of each electric device in the control cabinet 33 at all times, and controls the pre-configured sound and light alarm device to alarm in time when abnormalities occur.

In summary, the present invention has the following advantages compared with traditional techniques:

First, the air flotation membrane filtration purification system organically combines the air flotation process and the membrane filtration process, and the air flotation separation and membrane filtration are completed in the same pool, which makes full use of the space in the separation area of the air flotation pool, and does not need to build another pool, saving the occupied area. Land area and cost; taking a 10,000-ton water plant with the same treatment capacity as an example, if the traditional air flotation and sand filter process is designed, the air flotation outlet is connected to the sand filter, and the design filtration rate is 7m/h, the net filtration area needs 60 square meters, plus the water inlet and outlet areas and structural walls before and after the sand filter, it is necessary to add at least about 100 square meters of area to the construction of the filter on the basis of the area occupied by the air flotation membrane filtration purification system; The ultrafiltration membrane process design uses an ultrafiltration membrane with an outer diameter of 160mm, and a single water production rate of 1t/h requires 670 membranes. To arrange these membranes and supporting pipelines, it needs to be based on the area occupied by the air flotation membrane filtration purification system. At least increase the area of about 200 square meters.

Second, the air flotation membrane filtration purification system uses air flotation separation as the pretreatment of the membrane filtration treatment, which can improve the load resistance of the membrane filtration treatment, and at the same time, the microbubbles generated by the air flotation can frictionally clean the surface of the membrane filaments of the submerged membrane module The function can improve the anti-pollution of the membrane, and in turn, membrane filtration can replace the traditional water collection tank or perforated pipe water collection and discharge method of air flotation, and can greatly improve the effluent water quality of air flotation treatment; the air flotation membrane filtration purification system Membrane modules have high filtration precision and can ensure that the turbidity of the final effluent is below 0.2NTU. However, with the increase of the filtration time of the sand filter, if the backwashing is not timely, it is easy to have filter penetration, and the turbidity of the effluent cannot be guaranteed to be below 1NTU. , The effluent quality of the air flotation membrane filtration purification system is obviously better than that of the sand filter.

Third, the air flotation membrane filtration purification system sets multiple conical mud hoppers at the bottom of the pool. The mud discharge pipe of the bucket is discharged out of the pool, so that the water in the whole pool does not need to be drained, which reduces the self-water rate of the water plant; Fourth, the backwash cycle of the air flotation membrane filtration purification system is short, the time is short, and the water consumption is small. For a 10,000-ton water plant with the same processing capacity, the backwashing time of the air flotation membrane filtration purification system is one-tenth of that of the sand filter, the water consumption is one-seventh of the sand filter, and the backwashing cycle is shorter than that of the ultrafiltration membrane. The period is more than doubled.

Fifth, the membrane components of the air flotation membrane filtration purification system are easy to install and easy to maintain. For a 10,000-ton water plant with the same treatment capacity, the construction period is about 5 days shorter than that of ultrafiltration membranes, and the installation materials are 20% less than that of ultrafiltration membranes.

Sixth, the air flotation membrane filtration purification system only needs one pump to realize the functions of water production and backwashing, while the ultrafiltration membrane needs two pumps to realize it.

Seventh, the control device of the air flotation membrane filtration purification system automatically completes the process automatic operation of the air flotation membrane filtration purification system, which greatly reduces human operations and improves labor productivity.

The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this field Without departing from the scope of the technical solution of the present invention, the skilled person can use the technical content disclosed in the appeal to make some changes or modify it into an equivalent embodiment with equivalent changes, but any content that does not depart from the technical solution of the present invention, according to the present invention Any simple modifications, equivalent changes and modifications made to the above embodiments still fall within the scope of the technical solutions of the present invention.

Claims (10)

1. air supporting membrane filtration purification system, it is characterized in that: comprise, the filtering basin body (27) surrounded by exterior wall, dissolved air flotation device (28) and be arranged at the inner submerged membrane filtration unit (29) of filtering basin body (27);

Filtering basin body (27) interior pond is divided into into water buffer zone (2) by partition wall by described filtering basin body (27) inside, water inlet water distributing area (4), contact zone of dissolved air flotation (6), hold concurrently film filtration effluent district (7) in flotation separation zone;

Described water inlet buffer zone (2) and water inlet water distributing area (4) midfeather are the water distribution weir (3) that intakes;

Described filtering basin body (27) outer wall is provided with the water inlet pipe (1) for being communicated with water inlet buffer zone (2);

Described water inlet water distributing area (4) is communicated with into water water distributing area (4) with the water inlet distributing hole (5) of the division wall of contact zone of dissolved air flotation (6) by being arranged at contact zone of dissolved air flotation (6);

Described dissolved air flotation device (28) comprising: for exporting air dissolved pump or the dissolving of dissolved air water, the dissolved air water transport pipe (20) for the dissolved air water that leads and the micro bubble generation device (21) for generation of microbubble;

Described dissolved air water transport pipe (20) is fixed on and is processed with on the partition wall of water distributing hole (5), and the output terminal of one end and air dissolved pump or dissolving is fixed, and it is inner that the other end is inserted into contact zone of dissolved air flotation (6);

Described micro bubble generation device (21) is fixed on dissolved air water transport pipe (20) and is inserted into contact zone of dissolved air flotation (6) end;

Holding concurrently and to be processed with some cross sections at the bottom of film filtration effluent district (7) pond in the flotation separation zone of described filtering basin body (27) is taper bucket (22) to lower convexity; Described taper bucket (22) lower end is provided with shore pipe (23);

Described submerged membrane filtration unit (29) comprising: hold concurrently the inner immersion type membrane component (9) in film filtration effluent district (7), submerged membrane outfall sewer (12) and submerged membrane backwash inlet manifold (13) in the flotation separation zone being arranged at filtering basin body (27) by stainless steel frame (8);

Described submerged membrane outfall sewer (12) is double does submerged membrane water inlet manifold, and one end is communicated with each submerged membrane exit branch (10) of immersion type membrane component (9), and the other end is communicated with suction pump;

Described submerged membrane backwash inlet manifold (13) one end is communicated with immersion type membrane component (9) each submerged membrane backwash air intake branch (11), and the other end is communicated with gas blower;

Described filtering basin body (27) is provided with the medicine that each submerged membrane exit branch (10) of pipeline and immersion type membrane component (9) is communicated with and washes house steward (15);

Described filtering basin body (27) upper end is provided with scrapes slag travel mechanism (19) for scraper surface scum silica frost;

Described filtering basin body (27) is positioned at scrapes slag travel mechanism (19) end of travel and is provided with ash pit (17);

Described ash pit (17) and flotation separation zone film filtration effluent district (7) junction of holding concurrently is separated by deslagging weir (18).

2. air supporting membrane filtration purification system according to claim 1, is characterized in that: film filtration effluent district (7) inside of holding concurrently, the flotation separation zone of described filtering basin body (27) is provided with supporting beam (26) for strengthening the stainless steel frame (8) supporting immersion type membrane component (9).

3. air supporting membrane filtration purification system according to claim 1, is characterized in that: described in scrape slag travel mechanism (19) be assemblied in filtering basin body (27) sidewall arrange track on walk, and by motor drive walking; Described ash pit (17) is arranged at and filtering basin body (27) water-in opposite end.

4. air supporting membrane filtration purification system according to claim 1, is characterized in that: described immersion type membrane component (9), according to the requirement of effluent quality, adopts ultra-filtration membrane, or micropore filtering film.

5. air supporting membrane filtration purification system according to claim 1, is characterized in that: described immersion type membrane component (9) is washed house steward (15) by medicine and injected chlorine bleach liquor and carry out medicine and wash.

6. air supporting membrane filtration purification system according to claim 1, is characterized in that: the upper depth of the water submerging 1-2 rice of described immersion type membrane component (9).

7. air supporting membrane filtration purification system according to claim 1, is characterized in that: described ash pit (17) is provided with the wash tub pipe (16) for washing away ash pit (17).

8. air supporting membrane filtration purification system according to claim 1, is characterized in that: the connection of described each shore pipe (23) is cascaded, and be provided with on shore pipe (23) can autocontrol valve and manually-operated gate.

9. air supporting membrane filtration purification system according to claim 1, it is characterized in that: when processing the water yield and being large, filtering basin body (27) is concrete pouring structure, when processing the water yield and being less, filtering basin body (27) makes the small-sized water purification apparatus that a kind of enclosure material is metal or plastics.

10. air supporting membrane filtration purification system control method according to claim 1, is characterized in that: comprise the following steps,

Step one, needing in filtered water and the common injection process of dissolved air water, detect flotation separation zone to hold concurrently film filtration effluent district (7) water level, start submerged membrane outfall sewer (12) and go out water pump when water level arrives specified altitude assignment and realize filtered water and discharge;

Step 2, deslagging, after air supporting membrane filtration purification system runs the regular hour, strikes off surface, air supporting membrane filtration purification system filter tank dregs, drains; First control to strengthen flooding quantity, reduce aquifer yield and raise air supporting membrane filtration purification system filter tank surface level height, then startup is scraped slag travel mechanism (19) walking and is scraped slag; Dregs strike off and drain in ash pit (17), are then rinsed by wash tub pipe (16) and discharge; Tapping process terminates rear air supporting membrane filtration purification system and recovers normal operation;

Step 3, spoil disposal, after air supporting membrane filtration purification system runs the regular hour, air supporting membrane filtration purification system is deposited on to the settling of taper bucket (22), then discharged by shore pipe (23), the spoil disposal frequency of air supporting membrane filtration purification system is determined by air supporting membrane filtration purification system deposition;

Step 4, backwash, after immersion type membrane component (9) runs the regular hour, air supporting membrane filtration purification system is stopped to run, then the outbound course of suction pump changes submerged membrane outfall sewer (12) and becomes submerged membrane water inlet manifold, wash house steward (15) injection cleaning agent by medicine simultaneously and enter immersion type membrane component (9) through submerged membrane exit branch (10), wind is directed through submerged membrane backwash air intake branch (11) by submerged membrane backwash inlet manifold (13) and enters immersion type membrane component (9) assisted backwash by meanwhile gas blower work, backwash formation is directly fallen within taper bucket (22) and is then discharged by shore pipe (23), after backwash terminates, air supporting membrane filtration purification system recovers normal operation.