CN105347440A - Backwashing system and process for cleaning filter membrane - Google Patents

Abstract

The invention provides a backwashing system and a backwashing process for cleaning a filter membrane, and belongs to the technical field of water treatment. The invention provides a backwashing system for cleaning a filter membrane, which comprises a backwashing water pump, a backwashing water tank for storing used backwashing water and an adder. The water inlet of the backwashing water pump is communicated with a crude salt water tank in the reverse osmosis system through a pipeline and a valve, and the water outlet of the backwashing water pump is communicated with an ultrafiltration membrane group in the ultrafiltration system through a pipeline and a valve. The adder is used for adding an indicator for indicating whether the filter membrane in the ultrafiltration membrane group is cleaned or not, and is communicated with a pipeline for connecting the backwashing water pump and the ultrafiltration module through the pipeline. The backwashing system provided by the invention is skillfully arranged in the primary demineralized water preparation system, utilizes the byproduct water of the primary demineralized water preparation to be prepared as backwashing water, cleans and backwashes the filter membrane of the ultrafiltration membrane group, has good matching and convenient arrangement, and improves the utilization rate of water resources.

Description

Backwashing system and process for cleaning filter membrane

technical field

The invention relates to the technical field of water treatment, in particular to a backwashing system for cleaning a filter membrane and a process thereof.

Background technique

With the increasing shortage of water resources and the increasing water consumption of industrial production, water recycling technology has always been a key research direction. In recent years, many water treatment technologies have come out, such as microbial treatment, membrane technology treatment, reverse osmosis treatment, ion exchange treatment, etc., but there is a lack of personalized treatment solutions for specific water quality in specific areas, so the treatment effect is not satisfactory.

Water quality varies greatly depending on the region and time. On the basis of the development of existing water treatment technologies, it is a topic worth exploring to find a combined treatment process that can meet the local water quality conditions and obtain qualified industrial water. .

General industrial water, especially the water used in the petrochemical field, needs water quality to meet the needs of first-class desalinated water. Most enterprises use fresh groundwater to obtain first-class desalinated water after treatment. This method has a great demand for natural water and requires further treatment, which wastes a lot of manpower and material resources. The preparation of primary demineralized water from domestic sewage is a low-cost method for industrial water sources. However, in this process, due to the large amount of impurities in domestic sewage, each treatment module needs to be cleaned regularly to maintain the original treatment efficiency. Backwashing the module, especially the ultrafiltration module, is an effective cleaning method. In the existing system for preparing first-level desalinated water, the cleaning of the membrane group is not perfect, and whether the filter membrane is cleaned cannot be judged in time, and the cleaning system cannot be used with the entire system.

Contents of the invention

The problem to be solved by the present invention is that in the existing system for preparing the first-stage desalinated water, the cleaning of the membrane group is not perfect, the cleaning of the filter membrane cannot be judged in time, and the matching system cannot be used.

The first object of the present invention is to provide a backwashing system for cleaning the filter membrane installed in the first-stage desalinated water system, which can cooperate with the existing one-stage desalinated water system, and use the water in the system as the backwash water to device for backwashing or other treatment.

The backwashing system for cleaning the filter membrane is respectively connected with the ultrafiltration system and the reverse osmosis system, including a backwashing water pump, a backwashing water tank for storing used backwashing water, and an adder. The water inlet of the backwash water pump is connected with the crude brine pool in the reverse osmosis system through pipelines and valves, and the water outlet of the backwash water pump is connected with the ultrafiltration membrane group in the ultrafiltration system through pipelines and valves. The backwash pool is connected with the ultrafiltration membrane group. The adder is used to add an indicator indicating whether the ultrafiltration membrane group is cleaned, and it communicates with the pipeline connecting the backwash water pump and the ultrafiltration membrane group through a pipeline.

Further, the water inlet of the backwash water pump is also communicated with the ultrafiltration produced water pool in the ultrafiltration system through pipelines and valves.

Preferably, the water outlet of the backwash water pump is also connected to the multimedia filter in the ultrafiltration system through pipelines and valves, and the backwash water pool is connected to the multimedia filter through pipelines and valves.

Preferably, the water outlet of the backwash water pump is also connected to the feed inlet of the security filter in the reverse osmosis system through pipelines and valves.

The second object of the present invention is to provide a preparative primary desalination system comprising the above-mentioned backwashing system. The preparation of the primary desalinated water system includes the above-mentioned backwashing system for cleaning the filter membrane, and also includes an ultrafiltration system, a reverse osmosis system and an ion exchange system connected in sequence, and the backwashing system is connected with the ultrafiltration system and the reverse osmosis system respectively. The osmotic system is connected.

The ultrafiltration system includes the following equipment connected in sequence: sump, sump lift pump, regulating pool, multi-media feed pump, multi-media filter, self-cleaning filter, ultrafiltration membrane group, and ultrafiltration water production pool. The reverse osmosis system includes a reverse osmosis booster pump, a security filter, a high-pressure pump, a reverse osmosis membrane group, and a reverse osmosis production tank connected in sequence. The reverse osmosis booster pump communicates with the ultrafiltration water production pool.

The backwash system includes a backwash water pump, a backwash water tank for storing used backwash water, and an adder for adding an indicator indicating whether the ultrafiltration membrane group is cleaned. The water inlet of the backwash water pump is connected with the crude brine pool through pipelines and valves, the water outlet of the backwash water pump is connected with the ultrafiltration membrane group through pipelines and valves, and the water in the backwash water pump is in the ultrafiltration membrane group The direction of flow in the middle is opposite to the flow direction of water in the ultrafiltration system. The backwash water tank is connected with the ultrafiltration membrane group to collect and store the used backwash water. The adder communicates with the pipeline connecting the backwash water pump and the ultrafiltration membrane group through pipelines.

Preferably, the water inlet of the backwash water pump is also communicated with the ultrafiltration produced water pool through pipelines and valves.

Preferably, the water outlet of the backwash water pump is also connected to the feed port of the security filter and the multimedia filter through pipelines and valves, and the backwash water tank is connected to the multimedia filter through pipelines and valves.

Further, the ultrafiltration membrane group is provided with an ultrafiltration cross-flow pipeline, and its water outlet communicates with the regulating tank through pipelines and valves.

The third object of the present invention is to provide a backwashing process for cleaning the filter membrane, which is arranged in the entire process for preparing primary desalinated water. In the backwashing process, the crude brine obtained in the reverse osmosis process and a part of the ultrafiltration water in the ultrafiltration process are used as backwashing water, and an indicator is added to the backwashing water to backwash the filter membrane of the ultrafiltration module.

The indicator is acid or alkali, and the flow direction of the backwash water in the ultrafiltration membrane group is opposite to the flow direction of water in the ultrafiltration process.

The fourth object of the present invention is to provide a process for preparing primary desalinated water. In the process for preparing the primary desalinated water, the raw water is sequentially treated by an ultrafiltration process, a reverse osmosis process and an ion exchange process to obtain the primary desalinated water.

In the ultrafiltration process, the raw water is subjected to multi-media filtration and self-cleaning filtration after pH adjustment, and then ultrafiltration is performed in an ultrafiltration membrane group to obtain ultrafiltration water. The ultrafiltration membrane group is also provided with an ultrafiltration cross-flow pipeline, and the ultrafiltration cross-flow water is mixed with the raw water for pH adjustment.

In the reverse osmosis process, the ultrafiltration water is pressurized and then filtered for security, and then continues to be pressurized and enters the reverse osmosis membrane group for reverse osmosis treatment to obtain coarse brine and reverse osmosis water respectively. Reverse osmosis water is treated by ion exchange process to obtain primary desalinated water.

While the raw water is treated by the above-mentioned three-stage process, it is also treated by the backwash process. In the backwashing process, coarse brine and a part of ultrafiltration water are used as backwashing water. A part of the backwash water is added with an indicator to process the ultrafiltration membrane group, and the indicator is acid or alkali. Part of the backwash water cleans the multimedia filter device. Part of the backwash water is added to the reverse osmosis treatment as a reverse osmosis agent after adding antiscalant and reducing agent.

The advantages and positive effects of the present invention are: (1) The backwashing system provided by the present invention is cleverly arranged in the system for preparing the first-stage desalinated water, and the by-product water used for preparing the first-stage desalinated water is prepared as backwashing water, Cleaning and backwashing the devices in the first-level desalinated water system are well coordinated, easy to set up, and improve the utilization rate of water resources. (2) in the backwashing system provided by the present invention, adder is provided with, is used for adding indicator, when making backwash water cleans ultrafiltration membrane group, judges whether to clean ultrafiltration membrane group according to whether to produce precipitation, has improved Backwash efficiency. (3) In the backwash system provided by the present invention, the backwash water can also clean the multi-media filter in the ultrafiltration system, and also can enter the reverse osmosis system as a solvent of the reverse osmosis agent, further improving the efficiency of by-product water. utilization rate.

Description of drawings

Fig. 1 is a schematic diagram of the first-stage desalinated water system in the present invention.

detailed description

In order to better understand the present invention, the present invention will be further described below in conjunction with specific embodiments and accompanying drawings.

As shown in Figure 1, a system for preparing primary desalinated water includes a backwashing system for cleaning the filter membrane, an ultrafiltration system, a reverse osmosis system, and an ion exchange system connected in sequence, and the backwashing system is connected to the ultrafiltration system and the reverse osmosis system respectively. The osmotic system is connected.

The ultrafiltration system includes the following equipment connected in sequence: sump, sump lift pump, regulating pool, multi-media feed pump, multi-media filter, self-cleaning filter, ultrafiltration membrane group, and ultrafiltration water production pool. The ultrafiltration membrane group is equipped with an ultrafiltration cross-flow pipeline, and its water outlet is connected to the regulating tank through pipelines and valves, which reduces the discharge of water and saves water resources. Self-cleaning filter is a kind of filter that directly intercepts impurities in water, removes suspended solids and particulate matter in water, reduces turbidity, purifies water quality, reduces system dirt, bacteria and algae, rust, etc., to purify water quality and protect other equipment in the system. Working precision equipment.

The reverse osmosis system includes a reverse osmosis booster pump, a security filter, a high-pressure pump, a reverse osmosis membrane group, and a reverse osmosis production tank connected in sequence. The reverse osmosis booster pump is connected with the ultrafiltration water production tank. The function of the security filter is to intercept the particles larger than 5 μm from the leakage of the pre-product water or from the outside to prevent them from entering the reverse osmosis system. Such particles may break through the reverse osmosis membrane components after being accelerated by the high-pressure pump, causing a large amount of leakage. Salt situation while scratching the impeller of the high pressure pump.

The ion exchange system includes the following equipment connected in sequence: ion exchange feedwater pump, cation bed, weak yin bed, yin bed, desalinated water tank, and the ion exchange feed water pump is connected with the reverse osmosis production water tank. The primary desalted water obtained from the desalinated water pool is supplied to users through external pumps.

The backwash system includes a backwash water pump, a backwash water tank for storing used backwash water, and an adder for adding an indicator indicating whether the ultrafiltration membrane group is cleaned.

The water inlet of the backwash water pump is respectively connected with the crude brine pool and the ultrafiltration water production pool through pipelines and valves, and the water outlet of the backwash water pump is respectively connected with the ultrafiltration membrane group, multi-media filter and security filter through pipelines and valves. The feed port is connected. The flow direction of the water in the backwash water pump in the ultrafiltration membrane group is opposite to the flow direction of the water in the ultrafiltration system. The backwash pool is connected with the ultrafiltration membrane group. The adder communicates with the pipeline connecting the backwash water pump and the ultrafiltration membrane group through pipelines.

A process for preparing primary desalinated water. Raw water is sequentially treated by an ultrafiltration process, a reverse osmosis process and an ion exchange process to obtain a primary desalinated water.

In the ultrafiltration process, the raw water is subjected to multi-media filtration and self-cleaning filtration after pH adjustment, and then ultrafiltration is performed in the ultrafiltration membrane group to obtain ultrafiltered water. The ultrafiltration membrane group is also provided with an ultrafiltration cross-flow pipeline, and the ultrafiltration cross-flow water is mixed with the raw water for pH adjustment.

In the reverse osmosis process, the ultra-filtered water is pressurized and then subjected to security filtration, and then continues to be pressurized and enters the reverse osmosis membrane group for reverse osmosis treatment to obtain coarse brine and reverse osmosis water respectively. Reverse osmosis water undergoes ion exchange treatment to obtain primary desalinated water.

While the raw water undergoes the above-mentioned three-stage treatment, it is also subjected to backwashing process. In the backwashing process, coarse brine and a part of ultrafiltration water are used as backwashing water. A part of the backwash water is added with an indicator to treat the ultrafiltration membrane group, and the indicator is acid or alkali. Part of the backwash water cleans the multimedia filter device. Part of the backwash water is added to the reverse osmosis treatment as a reverse osmosis agent after adding antiscalant and reducing agent.

Specifically, the raw water enters the sump, passes through the sump lifting pump, lifts to the regulating pool, adjusts to a suitable pH value, and then enters the multi-media feed water pump. Through the action of the feed water pump, it enters the multi-media filter to filter out 80% of the Suspended impurities, then enter the self-cleaning filter, and then enter the ultrafiltration membrane group to obtain ultrafiltered water. The ultrafiltration cross-flow water is recycled into the regulating tank for reuse.

The ultrafiltration water enters the ultrafiltration water production pool, then passes through the reverse osmosis booster pump, enters the security filter, is pressurized by the high pressure pump, enters the reverse osmosis membrane group, and obtains reverse osmosis water.

The reverse osmosis water enters the reverse osmosis water production tank, and after being pressurized by the ion feed water pump, it enters the cation bed, weak yin bed, and yin bed respectively to remove anions and cations in the water to obtain first-level desalinated water, enters the desalinated water pool, and then passes through the external The supply pump is supplied to the user. The positive bed, weak shade bed, and shade bed are respectively provided with regeneration pools, and the produced water is regenerated and reused.

In the reverse osmosis treatment, the reverse osmosis treated water is obtained and concentrated brine is produced by-product, which enters the concentrated brine pool. The concentrated brine in the concentrated brine tank and the ultrafiltered water in the ultrafiltration water production tank are connected to the water inlet of the backwash water pump through the control of pipelines and valves. The valve can adjust the ratio of the two, and the outlet of the backwash water pump can be backwashed water.

Part of the backwash water is used as a solvent for the reverse osmosis agent, and after adding antiscalant and reducing agent, it enters the security filter. Part of the backwash water can also be used as cleaning water for the multi-media filter. A part of the backwash water is added with the indicator to backwash the filter membrane of the ultrafiltration membrane group. The indicator is acid or alkali, and the indicator reacts with the remaining impurities on the filter membrane to form a precipitate. Therefore, it can be judged whether the filter membrane of the ultrafiltration membrane group is cleaned by observing whether there is precipitation in the backwash water flowing out of the ultrafiltration membrane group. The judgment method is simple and fast, which saves the amount of backwash water and saves backwash time.

The embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention, and cannot be considered as limiting the implementation scope of the present invention. All equivalent changes and improvements made according to the scope of the present invention should still belong to the scope of this patent.

Claims (10)

1. A backwash system for cleaning the filter membrane, which is arranged in the system for preparing the first-stage desalinated water, communicates with the ultrafiltration system and the reverse osmosis system, and is characterized in that: it includes a backwash water pump, stores used backwash water Backwash tanks and adders; The water inlet of the backwash water pump is communicated with the crude brine pool in the reverse osmosis system through pipelines and valves, and the water outlet of the backwash water pump is communicated with the ultrafiltration membrane group in the ultrafiltration system through pipelines and valves; The backwash pool is connected with the ultrafiltration membrane group; The adder is used to add an indicator indicating whether the filter membrane in the ultrafiltration membrane group is cleaned, and it communicates with the pipeline connecting the backwash water pump and the ultrafiltration module through a pipeline. 2. The backwashing system for cleaning the filter membrane according to claim 1, characterized in that: the water inlet of the backwashing water pump is also communicated with the ultrafiltration water production tank in the ultrafiltration system through pipelines and valves. 3. The backwashing system of cleaning filter membrane according to claim 2, is characterized in that: the water outlet of described backwashing water pump is also communicated with the multimedia filter in the ultrafiltration system through pipeline and valve, backwashing The pool communicates with the multimedia filter through pipelines and valves. 4. The backwash system for cleaning the filter membrane according to claim 2, characterized in that: the water outlet of the backwash water pump is also connected to the feed port of the security filter in the reverse osmosis system through pipelines and valves Pass. 5. A system for preparing primary desalinated water, comprising the backwashing system described in claims 1-4, characterized in that: it also includes an ultrafiltration system, a reverse osmosis system and an ion exchange system connected in sequence, the reverse osmosis system The washing system is respectively connected with the ultrafiltration system and the reverse osmosis system; The ultrafiltration system includes the following equipment connected in sequence: sump, sump lift pump, regulating pool, multi-media feed pump, multi-media filter, self-cleaning filter, ultrafiltration membrane group, ultrafiltration water production tank; The reverse osmosis system includes a reverse osmosis booster pump, a security filter, a high-pressure pump, a reverse osmosis membrane group, and a reverse osmosis production tank connected in sequence; The reverse osmosis booster pump is connected to the ultrafiltration water production tank; The backwashing system includes a backwashing water pump, a backwashing pool storing used backwashing water and an adder for adding an indicator indicating whether the ultrafiltration membrane group is cleaned; The water inlet of the backwash water pump is connected with the crude brine pool through pipelines and valves, and the water outlet of the backwash water pump is connected with the ultrafiltration membrane group through pipelines and valves; the water in the backwash water pump is in the ultrafiltration module The middle flow direction is opposite to the flow direction of water in the ultrafiltration system; the backwash pool is connected with the ultrafiltration membrane group; the adder is connected with the pipeline connecting the backwash water pump and the ultrafiltration module through pipelines. 6. The system for preparing primary desalinated water according to claim 5, characterized in that: the water inlet of the backwash water pump is also connected to the ultrafiltration water production pool through pipelines and valves. 7. The first-stage desalinated water system according to claim 5 or 6, characterized in that: the outlet of the backwash water pump is also connected to the feed port of the security filter and the multimedia filter respectively through pipelines and valves The backwash pool is connected with the multimedia filter through pipelines and valves. 8. The system for preparing a first-stage desalinated water according to claim 5, characterized in that: the ultrafiltration module is provided with an ultrafiltration cross-flow pipeline, and its water outlet is connected to the regulating tank through pipelines and valves . 9. A backwashing process for cleaning filter membrane, characterized in that: Utilize the thick brine obtained in the reverse osmosis process and the ultrafiltration water in a part of the ultrafiltration process as backwashing water, after adding indicator in the backwashing water to the ultrafiltration The filter membrane of the filter module is backwashed; The indicator is acid or alkali, and the flow direction of the backwash water in the ultrafiltration membrane group is opposite to the flow direction of water in the ultrafiltration process. 10. A process for preparing one-stage desalinated water, comprising the backwashing process described in claim 9, characterized in that: the raw water is sequentially treated by an ultrafiltration process, a reverse osmosis process and an ion exchange process to obtain a first-stage desalinated water; In the ultrafiltration process, the raw water is subjected to multi-media filtration and self-cleaning filtration after pH adjustment, and then ultrafiltration is performed in the ultrafiltration membrane group to obtain ultrafiltration water; the ultrafiltration module is also equipped with an ultrafiltration cross-flow pipe Road, ultra-filtered cross-flow water mixed with raw water for pH adjustment; In the reverse osmosis process, the ultrafiltration water is pressurized and then filtered for security, and then continues to be pressurized and enters the reverse osmosis module for reverse osmosis treatment to obtain crude brine and reverse osmosis water respectively; Demineralized water; While the raw water is treated by the above-mentioned three-stage process, it is also treated by the backwashing process; In the backwash process, crude brine and a part of ultrafiltration water are used as backwash water; part of the backwash water is added to the indicator to treat the ultrafiltration module, and the indicator is acid or alkali; part of the backwash water is used for multiple The medium filter device is cleaned; part of the backwash water is added with antiscalant and reducing agent and then added to the reverse osmosis treatment as a reverse osmosis agent.