CN213171909U

CN213171909U - Wastewater treatment system

Info

Publication number: CN213171909U
Application number: CN202021258848.1U
Authority: CN
Inventors: 陈智根; 张勇; 翟君锋
Original assignee: Chengdu Hongrun Technology Co ltd
Current assignee: Chengdu Hongrun Technology Co ltd
Priority date: 2020-06-30
Filing date: 2020-06-30
Publication date: 2021-05-11
Anticipated expiration: 2030-06-30

Abstract

The utility model discloses a wastewater treatment system, which comprises a primary filtering device, a membrane clarification unit, a membrane separation device and a membrane concentration unit which are connected in sequence; the membrane concentration unit comprises a concentration desalting device for intercepting most of inorganic salts and a fine desalting device for further intercepting the inorganic salts, which are connected in sequence. The utility model also discloses a wastewater treatment method. Therefore, the wastewater treatment system of the utility model solves the problem that the membrane concentration desalination process does not output liquid, and also solves the technical problem that the effluent salt content exceeds the standard and can not be reused for production. The optimal comprehensive treatment cost is obtained, and the purposes of energy conservation and consumption reduction are achieved.

Description

Wastewater treatment system

Technical Field

The utility model relates to a waste water technical field particularly, relates to a wastewater treatment system.

Background

The industrial wastewater with high salt content, excessive COD and large discharge amount causes no small environmental protection pressure for enterprises. In the prior art, the evaporation and the reuse are carried out by adopting a decompression concentration mode, the one-time investment of equipment is large, and the operation cost is high. In addition, some types of production wastewater have high COD content, and the organic matters in the solution change in electrolyte environment and temperature in the operation process of evaporation equipment, so that protein in the solution is denatured and precipitated, the viscosity of the solution is increased, scaling is avoided to cause poor heat exchange effect, the operation cost is increased, and a thermal concentration circulating pipeline is blocked to interrupt operation or even damage the equipment. In addition, due to the increase of the viscosity of the solution, foams are easy to generate and enter a clear liquid system together, and the quality of the distillate is seriously influenced.

Therefore, a waste water treatment system with lower comprehensive treatment cost and less energy consumption is needed.

SUMMERY OF THE UTILITY MODEL

The utility model discloses a main aim at provides a wastewater treatment system to it is with high costs to solve among the prior art wastewater integrated treatment, the problem that the energy consumption is big.

In order to achieve the above object, according to an aspect of the present invention, there is provided a wastewater treatment method including the steps of:

(a) primarily filtering the wastewater stock solution to intercept large solid particle impurities to obtain primary filtrate, introducing the primary filtrate into a membrane clarification unit to intercept solid suspended matters and macromolecular impurities to obtain membrane clarified filtrate;

(b) intercepting the membrane clarified filtrate by a membrane separation device to obtain membrane separation liquid, then sequentially intercepting most of inorganic salt by the membrane separation liquid through a concentration desalting device in a membrane concentration unit, further intercepting the inorganic salt by a fine desalting device to obtain clear liquid reaching the standard, returning the concentrated liquid intercepted by the fine desalting device to the concentration desalting device, wherein the operating pressure of the concentration desalting device is more than or equal to 2.5MPa, and the operating pressure of the fine desalting device is less than 2.5 MPa.

Further, when the wastewater stock solution is a high-salt protein solution:

adjusting the pH value of the wastewater stock solution before the primary filtration in the step (a), and monitoring the pH value of the wastewater stock solution to ensure that the protein in the wastewater stock solution entering the primary filtration is zero;

and (c) before the membrane separation liquid in the step (b) enters the membrane concentration unit, introducing the membrane separation liquid into an organic separation unit for organic separation, removing most macromolecular organic matters in the organic separation unit through a separation device, further intercepting the organic matters in the device through an interception device to obtain organic separation liquid, and then introducing the organic separation liquid into the membrane concentration unit.

Furthermore, a first intermediate tank is arranged between the separation device and the interception device, and a concentrated liquid outlet of the membrane separation device is connected with the first intermediate tank;

a second intermediate tank is arranged between the membrane separation device and the concentration desalting device, and a concentrated solution outlet of the fine filtering device is connected with the second intermediate tank;

a third intermediate tank is arranged between the concentration desalting device and the fine desalting device;

and a fourth intermediate tank is arranged between the interception device and the membrane separation device.

Further, the membrane clarification unit comprises an inorganic membrane filtering device and an organic membrane filtering device; the cut-off molecular weight of the membrane filtration device is 5000 Da; 8000D; a 10000 Da; 30000 Da; 50000Da, 80000Da, 100000Da, 150000Da, 200000Da and 250000 Da.

Further, the liquid inlet of the membrane clarification unit is also provided with a primary filtering unit, the primary filtering unit comprises a cloth bag/plate frame filtering device, and a circulating tank is arranged between the primary filtering unit and the membrane clarification unit.

Further, the filtration precision of the cloth bag/plate frame filter device is one of 0.5 μm, 1 μm, 5 μm and 10 μm.

Further, the organic separation unit comprises a first roll-type ultrafiltration or nanofiltration membrane organic separation device and a second roll-type ultrafiltration or nanofiltration membrane organic separation device.

Further, the molecular weight cut-off of the first roll type ultrafiltration or nanofiltration membrane organic separation device is one of 10000Da, 8000Da, 5000Da, 3000Da, 2500Da and 1000Da, and the molecular weight cut-off of the second roll type ultrafiltration or nanofiltration membrane organic separation device is one of 2500Da, 1000Da,800Da, 600Da, 500Da,300Da and 150 Da.

Further, the membrane separation device comprises a roll-type, butterfly-type or plate-type membrane nanofiltration device.

Further, the reverse osmosis filtration unit comprises a first reverse osmosis membrane filtration device and a second reverse osmosis membrane filtration device.

Further, the cut-off molecular weight of the first reverse osmosis membrane filtration device is one of 300Da,150Da, 100Da, 50Da, 30Da and 10 Da.

Further, the filtering precision of the second reverse osmosis membrane filtering device is one of 300Da,150Da, 100Da, 50Da, 30Da and 10 Da.

According to one aspect of the utility model, a wastewater treatment system is provided, which comprises a primary filtering device, a membrane clarification unit, a membrane separation device and a membrane concentration unit which are connected in sequence;

the membrane concentration unit comprises a concentration desalting device for intercepting most of inorganic salts and a fine desalting device for further intercepting the inorganic salts, which are connected in sequence.

Further, be equipped with the flocculation basin before the primary filter device be equipped with the circulation jar between primary filter device and the membrane clarification unit, the flocculation basin even has first pH monitor, the circulation jar even has the second pH monitor, still be equipped with organic separating element between membrane clarification unit and the membrane concentration unit, organic separating element is including the separator of the separation macromolecule organic matter that connects gradually, the intercepting device of further interception organic matter.

Further, the membrane clarification unit comprises an inorganic membrane filtering device and an organic membrane filtering device; roll type membrane filtration device, disc type membrane filtration device, plate type membrane filtration device, hollow fiber membrane filtration device, tubular membrane filtration device, with molecular weight cutoff of 5000Da, 8000Da, 10000Da, 30000Da, 50000Da, 80000Da, 100000Da, 150000Da, 200000Da, 250000 Da.

Therefore, the wastewater treatment system of the utility model solves the problem that the membrane concentration desalination process does not produce liquid, and also solves the technical problem that the effluent salt content exceeds the standard and can not be reused for production. The optimal comprehensive treatment cost is obtained, and the purposes of energy conservation and consumption reduction are achieved.

The present invention will be further described with reference to the accompanying drawings and the detailed description. Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The accompanying drawings, which form a part of the disclosure, are included to assist in understanding the disclosure, and the description provided herein and the accompanying drawings, which are related thereto, are intended to explain the disclosure, but do not constitute an undue limitation on the disclosure.

In the drawings:

FIG. 1 is a schematic view of the equipment flow of the wastewater treatment system of the present invention.

Detailed Description

The present invention will be described more fully with reference to the accompanying drawings. Those of ordinary skill in the art will be able to implement the invention based on these descriptions. Before the present invention is described with reference to the accompanying drawings, it is to be noted that:

the technical solutions and features provided in the present invention in each part including the following description may be combined with each other without conflict.

Moreover, the embodiments of the invention described in the following description are generally only examples of a subset of the invention, and not all examples. Therefore, all other embodiments obtained by a person of ordinary skill in the art without creative efforts based on the embodiments of the present invention shall fall within the protection scope of the present invention.

With respect to the terms and units of the present invention. The terms "comprising," "having," and any variations thereof in the description and claims of this invention and the related sections are intended to cover non-exclusive inclusions.

As shown in fig. 1:

a method for treating wastewater comprising the steps of:

a, introducing a wastewater stock solution into a membrane clarification unit 12 to intercept solid suspended matters and macromolecular impurities to obtain a first treatment solution;

b, introducing the first treatment liquid into an organic separation unit 2, removing most macromolecular organic matters through a separation device 2, and further intercepting the organic matters in the device through an interception device 22 to obtain second treatment liquid;

and c, introducing the second treatment liquid into a membrane concentration unit, removing micromolecular organic matters and part of divalent inorganic salts through a membrane separation device 3, sequentially intercepting most of the inorganic salts through a concentration desalting device 41 in a reverse osmosis filtration unit 4, and further intercepting the inorganic salts through a fine desalting device 42 to obtain standard-reaching clear liquid, wherein the operating pressure of the concentration desalting device 41 is more than or equal to 2.5MPa, and the operating pressure of the fine desalting device 42 is less than 2.5 MPa.

A first intermediate tank 5 is arranged between the separation device 21 and the interception device 22, and a concentrated solution outlet of the membrane separation device 3 is connected with the first intermediate tank 5;

a second intermediate tank 6 is arranged between the membrane separation device 3 and the concentration desalination device 41, and a concentrated solution outlet of the fine filtration device is connected with the second intermediate tank 6.

A third intermediate tank 7 is arranged between the concentration desalting device 41 and the fine desalting device 42.

The membrane clarification unit 12 comprises an inorganic membrane filtration device, an organic membrane filtration device, a roll-type membrane filtration device, a butterfly-type membrane filtration device, a plate-type membrane filtration device, a hollow fiber membrane filtration device, a tubular membrane filtration device, and has a molecular weight cutoff of one of 5000Da, 8000D, a 10000Da, 30000Da, 50000Da, 80000Da, 100000Da, 150000Da, 200000Da, 250000 Da.

The liquid inlet of the membrane clarification unit 12 is also provided with a primary filtering unit 11, the primary filtering unit 11 comprises a cloth bag/plate frame filtering device, and a circulating tank 8 is arranged between the primary filtering unit 11 and the membrane clarification unit 12.

The filtration precision of the cloth bag/plate frame filter device is one of 0.5 μm, 1 μm, 5 μm and 10 μm.

The organic separation unit 2 comprises a first roll type ultrafiltration or nanofiltration membrane organic separation device and a second roll type ultrafiltration or nanofiltration membrane organic separation device.

The cut-off molecular weight of the first roll type ultrafiltration or nanofiltration membrane organic separation device is one of 10000Da, 8000Da, 5000Da, 3000Da, 2500Da and 1000Da, and the cut-off molecular weight of the second roll type ultrafiltration or nanofiltration membrane organic separation device is one of 2500Da, 1000Da,800Da, 600Da, 500Da,300Da and 150 Da.

The membrane separation device 3 comprises a rolled type, butterfly type or plate type nanofiltration membrane device.

The reverse osmosis filtering unit 4 comprises a first reverse osmosis membrane filtering device and a second reverse osmosis membrane filtering device.

The first reverse osmosis membrane filtration device has a molecular weight cut-off of one of 1000Da,800Da,500Da,300Da,150Da, 100Da and 50Da, and the second reverse osmosis membrane filtration device has a filtration precision of one of 1000Da,800Da,500Da,300Da,150Da, 100Da and 50 Da.

The utility model relates to a wastewater treatment system, which comprises a primary filtering device 11, a membrane clarification unit 12, a membrane separation device 3 and a membrane concentration unit which are connected in sequence;

the membrane concentration unit comprises a concentration desalting device 41 for intercepting most of inorganic salts and a fine desalting device 42 for further intercepting the inorganic salts, which are connected in sequence.

Be equipped with before primary filter device 11 flocculation basin 13 be equipped with between primary filter device 11 and the membrane clarification unit 12 circulation jar 8, flocculation basin 13 even has first pH monitor 131, circulation jar 8 even has second pH monitor 81, still be equipped with organic separating element 2 between membrane clarification unit 12 and the membrane concentration unit, organic separating element 2 is including the separator 21 of the separation macromolecule organic matter that connects gradually, further interception intercepting organic matter intercepting device 22.

The membrane clarification unit 12 comprises an inorganic membrane filtration device and an organic membrane filtration device; the cut-off molecular weight of the membrane filtration device is 5000 Da; 8000D; a 10000 Da; 30000 Da; 50000Da, 80000Da, 100000Da, 150000Da, 200000Da and 250000 Da.

The membrane separation device 3 comprises a spiral wound membrane nanofiltration device.

The molecular weight cut-off of the first reverse osmosis membrane filtration device is one of 300Da,150Da, 100Da, 50Da, 30Da and 10 Da.

The filtering precision of the second reverse osmosis membrane filtering device is one of 300Da,150Da, 100Da, 50Da, 30Da and 10 Da.

Preliminary filtration of waste water and adjustment of pH

The wastewater at each process point enters a wastewater collection tank after most of large particles, solidified grease and strip-shaped impurities are intercepted by a primary filtering device 11. The wastewater of each process point is uniformly mixed in a wastewater collection tank and then enters a pH adjusting tank, the pH value of the mixed wastewater is about 8.5 and then enters an air floatation machine treatment process, the floating slag floating on the water surface is separated by a slag skimming barrel of the air floatation machine and then enters a precise filtration process, fine particles in the solution are filtered by a precise filter and then enter a flocculation process, and the flocculation process is subjected to flocculation treatment and the supernatant is settled and enters a membrane clarification process. Solid matters generated at the lower part of the sedimentation tank enter other working procedures for treatment.

To the waste water that does not contain high salt protein, the waste water of each technology production link enters into different collecting ponds after categorised, and after waste water subsided in the collecting pond, adopts sack/sheet frame filter equipment to filter most large granule impurity, under the condition that needs carry out pH regulation to waste water, can carry out pH value after and adjust, generally adopts to set up the pH equalizing basin behind the collecting pond, and the supernatant in the pH equalizing basin filters through sack/sheet frame.

Membrane clarification

The mixed wastewater after the precise filtration enters a membrane clarification process: a membrane clarification system is used for filtering and intercepting a small amount of grease, fine suspended solid and part of macromolecular impurities which cannot be pretreated in feed liquid at high precision, and clear liquid is formed and enters an organic separation process. The intercepted small amount of grease, fine solid suspended matters and part of macromolecular impurities form concentrated solution due to the reduction of volume, and the concentrated solution is conveyed to a flocculation process. The macromolecular impurities are aggregated, settled and layered by adding a flocculating agent. And the supernatant enters a membrane clarification process and enters a membrane clarification system after being subjected to security filtration. And the clear liquid enters an organic separation process to remove macromolecular protein organic matters. The concentrated solution enters a flocculation process, and clear solution after flocculation layering returns to membrane clarification treatment; the lower sediment of the flocculation is combined with other impurities for treatment.

The membrane clarification process has the functions of removing fine suspended solids and macromolecular impurities: on one hand, the feeding condition of the organic separation membrane is achieved; on the other hand, after part of macromolecular impurities are removed, the burden of subsequent procedures is lightened, and the method has the advantages that compared with flocculation after pretreatment of the traditional process and then membrane clarification: a. the volume of the wastewater to be flocculated is less than 10 percent of the original volume, the addition amount of the flocculating agent is greatly reduced, and the economy is good; b. the additive is greatly reduced, the subsequent environment-friendly treatment pressure is reduced, the pollution and blockage of a subsequent organic film are reduced, the running cost is low, and the process is stable; c. the concentrated solution after the membrane clarification has high impurity content, is more beneficial to the flocculation and sedimentation reaction process, and has more scientific and reasonable process design; d. the membrane clarification process belongs to precision control, and overcomes the process problem of effluent quality stability caused by flocculation sedimentation due to fluctuation of raw water quality and process conditions.

Membrane elements used in the membrane clarification device are classified according to materials: inorganic films and organic films; the method is divided into the following steps according to the filtering precision: microfiltration (MF), Ultrafiltration (UF), Nanofiltration (NF), and Reverse Osmosis (RO); the method is divided into the following steps according to different structural forms of the membrane: plate type, roll type, disc type, tubular membrane and hollow fiber membrane.

The operation indexes are as follows:

organic separation step

The process comprises the following steps:

after a small amount of grease, fine suspended solid and part of macromolecular impurities are intercepted by a membrane clarification process, the quality of the mixed wastewater reaches the feeding requirement of an organic separation membrane; meanwhile, after the organic macromolecules are clarified and intercepted by the membrane, the load of the subsequent process is also reduced. The mixed wastewater enters an organic separation process, and a 2500Da filter precision membrane is adopted to cut most of macromolecular organic impurities (organic separation section): the concentrated solution is conveyed to other processes to recover protein; the clear solution permeating the membrane still contains a large amount of organic matters, so that the filtration is carried out again by adopting a membrane with the filtration precision of 1000 Da: organic matters penetrating through the 2500Da filtering precision membrane in the organic separation clear liquid are intercepted to form concentrated liquid, and the concentrated liquid returns to the 2500Da filtering precision membrane inlet to be mixed with feed liquid clarified by the membrane and then enters the 2500Da filtering precision membrane; the pure liquid passing through the membrane with the filtration precision of 1000Da is taken as clear liquid and enters a concentration procedure for further treatment.

The utility model discloses a utility model conceives and lies in:

by adopting a membrane clarification and organic separation double-membrane process, the organic separation feeding is not influenced by process fluctuation, and the process is stable; two or more sections of membranes with different filtering precisions are connected in series, namely, the organic separation adopts a mode of high molecular interception and low molecular interception, so that the membrane has uniform load distribution, stable flux, low energy consumption and small membrane pollution degree.

The organic separation process has the functions of: removing organic macromolecular impurities, on one hand, recovering and purifying protein in the wastewater to be sold as a product; the other is to reduce the load of the subsequent concentration step.

Its advantage compared with prior art lies in: compared with the prior art that organic matters are separated by a single filtration precision membrane, the membrane flux attenuation of the first single filtration precision membrane concentrated material is very fast, the membrane flux can be maintained only by simply increasing the pressure, the energy consumption is high, and the membrane pollution condition is serious; the second point is that the concentration of the membrane surface of the single filtration precision membrane concentrated material is high, the content of organic matters in the clear solution permeating the membrane is high, and great filtration pressure is caused to the subsequent concentration process or the technical standard is difficult to reach; and the third point adopts the combined use of two membranes with filtering precision in a separation section and an interception section, the membrane load distribution is uniform, the membrane flux is stable, and the low-pressure operation is economic and reasonable. And the fourth point adopts the combined use of two membranes with filtering precision of a separation section and an interception section, thereby not only ensuring the high content of concentrated solution, but also ensuring that clear solution reaches the technical standard, and the process design is scientific and reasonable. And the fifth point adopts the combined use of two membranes with filtering precision of a separation section and an interception section, the membrane load is distributed uniformly, the membrane surface concentration is low, the membrane pollution degree is low, and the service life of the membrane is greatly prolonged.

Membrane elements used in the organic separation process: the method is divided into the following steps according to materials: inorganic films and organic films; the method is divided into the following steps according to the filtering precision: microfiltration (MF), Ultrafiltration (UF), Nanofiltration (NF), and Reverse Osmosis (RO); the method is divided into the following steps according to different structural forms of the membrane: plate type, roll type, disc type, tubular membrane and hollow fiber membrane. According to different membrane operating pressures, the method can be divided into the following steps: low pressure film (less than 2.5MPa) and high pressure film (more than or equal to 2.5 MPa).

Organic separation performance index:

concentration stage

The process comprises the following steps:

clear liquid after tiny molecular protein is intercepted by the organic separation intercepting section, the content of organic matters is greatly reduced, and most of the residual components in the wastewater are inorganic salt. The clear liquid enters a pre-filtering section of a concentration procedure to remove small molecular organic matters and part of divalent inorganic salt: intercepting micromolecular organic matters and divalent inorganic salts to form concentrated solution, returning the concentrated solution to the organic separation interception segment, mixing the concentrated solution with clear liquid from the organic separation segment, and entering an organic separation interception segment membrane separation system; the mixed wastewater intercepted with the micromolecular organic matter and the divalent inorganic matter passes through a concentration prefiltering membrane to form clear liquid and enters a high-pressure concentration section of a concentration process.

The high-pressure concentration section intercepts most of inorganic salt and fine molecular organic matters: intercepting fine molecular organic matters and most of inorganic salts to form concentrated solution, discharging the concentrated solution out of a system, and performing thermal concentration and drying to obtain solids; the mixed wastewater forms clear liquid by intercepting the permeation film of fine molecular organic matters and most of inorganic salts. Because the concentration of the membrane surface of the concentration section is very high, the clear liquid also contains part of inorganic salt which can not reach the technical standard. The clear liquid is discharged through the high-pressure concentration section of the concentration process, and can reach the expected technical standard only through the low-pressure fine filtration of the concentration process.

The low-pressure fine filtration section has low membrane surface concentration, so that the clear liquid discharged from the system can reach the expected technical standard and be reused for production, and the purposes of energy conservation and consumption reduction are achieved: after intercepting a small part of inorganic salt by low-pressure fine filtration, forming a concentrated solution, returning to a high-pressure concentration section of a concentration process, mixing with the pre-filtered clear solution, and entering a high-pressure concentration system; the clear liquid after trapping a small part of inorganic salt reaches the expected technical index and is reused for production.

The concentration process has the effects that: high-pressure membrane filtration with low operation cost is adopted for concentration, and a large amount of water is removed. Then, low-pressure thermal concentration crystallization or other evaporation drying methods are adopted to recover inorganic salt solids, so that the aim of greatly reducing the comprehensive operation cost is fulfilled.

Its advantage compared with prior art lies in: recovering inorganic salt solid by low-pressure heat concentration crystallization or other evaporation drying methods, or combining the low-pressure heat concentration crystallization or other evaporation drying with single-stage high-pressure membrane filtration: a. the single low-pressure heat concentration crystallization or other evaporation drying methods recover inorganic salt solids, and the operation cost is very high due to the low concentration and large volume of the inorganic salt. The membrane filtration cost is 10-15% of the heat concentration cost, so the comprehensive operation cost of combining the heat concentration and the high-pressure membrane concentration is greatly reduced; b. the single high-pressure membrane concentration equipment is high in investment, high-concentration clear liquid on the membrane surface during operation hardly reaches the preset technical standard, and the combination of high-pressure membrane concentration and low-pressure membrane concentration can ensure that the content of inorganic salt in the concentrated liquid of the system is high and the clear liquid reaches the preset technical standard; c. the pre-filtration is added before the high-pressure membrane concentration and the low-pressure membrane concentration, so that a large amount of divalent inorganic salt is removed, the load of a subsequent high-pressure concentration section is reduced, the process configuration is scientific and reasonable, the operating pressure of the high-pressure concentration section is properly reduced, and the comprehensive operating cost of equipment can be obviously reduced. d. The pre-filtration is added before the high-pressure membrane concentration and the low-pressure membrane concentration, so that a large amount of divalent inorganic salt is removed, the load of a subsequent high-pressure concentration section is reduced, the running concentration of inorganic salt on the membrane surface can be obviously reduced, the membrane pollution degree is low, and the service life of the membrane is greatly prolonged.

Membrane elements used in the concentration process stage: the method is divided into the following steps according to materials: inorganic films and organic films; the method is divided into the following steps according to the filtering precision: microfiltration (MF), Ultrafiltration (UF), Nanofiltration (NF), and Reverse Osmosis (RO); the method is divided into the following steps according to different structural forms of the membrane: plate, roll, disk, tubular and hollow fiber membranes. According to different membrane operating pressures, the method can be divided into the following steps: low pressure film (less than 2.5MPa) and high pressure film (more than or equal to 2.5 MPa).

The operation index is as follows:

example 1

The utility model is applied to the treatment of high-salt protein liquid

The high-salt protein liquid stock solution enters a wastewater treatment system according to the following process parameters. The interface material is only sampled and detected, and the statistical average data is as follows:

processing the request

The quality of the clear water after the wastewater is treated is required to reach the standard of GB/T19923-2005 'quality of industrial water for municipal sewage recycling', Table 1, 'water for process and product'.

The pretreatment part in the process adopts an ultrafiltration membrane which has high strength, good pollution resistance, economy and easy obtainment, and the membrane is durable and is not easy to block. The membrane also has the defect that hard particles or large solid particles in stock solution enter the ultrafiltration membrane at a high speed under the conveying of a pump, the surface of the membrane is easily scratched, and thus membrane elements are damaged, so that the stock solution is primarily filtered by a cloth bag or a plate frame with the thickness of 5 mu m before entering ultrafiltration pretreatment, and the ultrafiltration membrane is protected from being damaged.

Membrane clarification system

The clarifying system is in the most heavy-load and most polluted environment in the whole process, so that the specific structure is selected to improve the anti-pollution performance of the membrane, and the specific design on the operation process is also needed. In view of the working condition of the clarifying membrane, an open type operation process is preferably adopted. The greatest disadvantage of the open process is that it can only be operated batchwise. Thus, for 1300m³The throughput of/d required 80m³The circulating tank can be adapted to the requirements of the process, and 20m can be adopted for cleaning and maintenance convenience³And 60m³The circulation tanks are connected in parallel one by one. Because the membrane clarification process is relatively independent and is not suitable for mixing with other processes,

organic separation unit

The organic separation unit integrates the separation section and the interception section of organic separation into a skid-mounted base. The material membrane used in the organic separation section can exert the best advantage of difficult blockage of cross flow filtration only under a certain membrane surface flow rate. Therefore, it is desirable to use a semi-open and semi-closed process to reduce the operating cost of the organic separation unit. The organic separation unit consists of a separation section and an interception section, and two intermediate tanks are required to be configured at the same time. The organic separation unit is configured to be 10m due to the adoption of a semi-open and semi-close operation process and the consideration of the cleaning and maintenance requirements of the membrane equipment³And 15m³One for each tundish.

In addition, if the concentrated solution is discharged in a sectional manner, the total amount of the concentrated solution cannot be controlled within a specified range, so that the concentrated solution flows back to the inlet of the separation section through the interception section, and is then discharged out of the system after being concentrated by the separation section.

In the test process, the applicant finds that most of organic protein is trapped after the separation section, the concentrated solution in the interception section is turbid, and in order to solve the technical problem of turbidity, the applicant proves through experiments that the organic protein precipitation can be well solved by increasing the pH value at the interception section. Therefore, under the condition of certain pH value, the solution system is far away from the isoelectric point of the protein, and the solution does not generate turbidity. After the treatment method is adopted, even if the solution is added into the circulating tank to cause the sudden temperature rise and drop of the solution, the phenomenon of turbidity of the solution can not occur. Therefore, maintaining a certain pH of the feed solution is a very effective solution to organic pollution. In the actual operation process, pH adjusting device 221 specifically is including the flocculation basin, and the clarification circulation jar sets up a pH on-line monitoring appearance in the flocculation basin, and solution flocculation is accomplished and pH reaches and sets for the within range back pump in the clarification circulation jar again, also sets up a pH on-line monitoring appearance in the inside of clarification circulation jar simultaneously, confirms the pH of material once more, if special circumstances appears, when pH reaches the limit that "muddy" appears in the solution, the system reports to the police and the time delay is shut down.

Nanofiltration system

The nanofiltration system functions relatively independently. Because the nanofiltration has a certain effect on saltThe interception efficiency of the system is improved, so that the load of the subsequent process can be reduced, and the continuous and stable operation of the subsequent process is ensured. The nanofiltration system has higher operating pressure, is suitable for adopting a half-open and half-close process, and adopts two 15m nanofiltration systems in production due to the huge nanofiltration system and the complicated pipelines³The intermediate tank is used for containing liquid and cleaning and maintaining.

In addition, in order to reduce the discharge amount of the concentrated liquid of the whole system, the nanofiltration concentrated liquid is not suitable to be discharged independently. The nanofiltration concentrated solution is reasonably returned to the inlet of the interception section from the technology (the effluent of the separation section is not diluted) and the economy.

Membrane concentration desalination system

The concentration desalination system is used as a core part of the whole large system, and other processes are arranged around the concentration desalination system. The concentration section and the fine filtration section of the concentration desalting process are formed according to different functions. As previously mentioned, nanofiltration systems are too bulky to be conveniently integrated with a concentration desalination system on a skid-mounted base. Therefore, the concentration process in production only consists of a concentration section and a fine filtration section.

Because the osmotic pressure of high salt solution on the membrane surface is overcome, the operation pressure of the concentration desalination process is very high, and the method is only suitable for adopting a half-open and half-closed process with the configuration of 10m³And 20m³One for each tundish.

Although the feed liquid entering the system is prefiltered by the nanofiltration membrane to intercept a part of salt, the salt content in the feed liquid is too high, so that the solvent needs high osmotic pressure to overcome the resistance of a gel layer on the membrane surface to permeate the membrane to form clear liquid.

The utility model discloses the clear water after with concentrated desalination and smart filtration is used for the washing of whole membrane system. In order to keep enough clean water for the membrane cleaning system for a long time, two 50m devices are arranged in the process³A clean water tank. The clean water pump attached to the clean water tank adopts a constant pressure control technology to ensure that once the automatic valve is opened, enough clean water can be delivered to each process and working section. The wash water return production system can be designed in an overflow manner to save energy consumption.

The contents of the present invention have been explained above. Those of ordinary skill in the art will be able to implement the invention based on these descriptions. Based on the above-mentioned contents of the present invention, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the protection scope of the present invention.

Claims

1. The wastewater treatment system is characterized by comprising a primary filtering device (11), a membrane clarification unit (12), a membrane separation device (3) and a membrane concentration unit which are sequentially connected;

the membrane concentration unit comprises a concentration desalting device (41) for intercepting most of inorganic salts and a fine desalting device (42) for further intercepting the inorganic salts, which are connected in sequence.

2. The wastewater treatment system according to claim 1, wherein a flocculation tank (13) is arranged in front of the primary filtering device (11), a circulating tank (8) is arranged between the primary filtering device (11) and the membrane clarification unit (12), the flocculation tank (13) is connected with a first pH monitor (131), the circulating tank (8) is connected with a second pH monitor (81), an organic separation unit (2) is further arranged between the membrane clarification unit (12) and the membrane concentration unit, and the organic separation unit (2) comprises a separation device (21) for separating macromolecular organic matters and an interception device (22) for further intercepting the organic matters which are sequentially connected.

3. The wastewater treatment system according to claim 2, characterized in that a first intermediate tank (5) is arranged between the separation device (21) and the interception device (22), and the concentrated liquid outlet of the membrane separation device (3) is connected with the first intermediate tank (5);

a second intermediate tank (6) is arranged between the membrane separation device (3) and the concentration desalting device (41), and a concentrated solution outlet of the fine filtering device is connected with the second intermediate tank (6);

a third intermediate tank (7) is arranged between the concentration desalting device (41) and the fine desalting device (42);

a fourth intermediate tank (9) is arranged between the interception device (22) and the membrane separation device (3).

4. The wastewater treatment system according to claim 2, wherein the organic separation unit (2) comprises a first roll-to-roll ultrafiltration or nanofiltration membrane organic separation device, a second roll-to-roll ultrafiltration or nanofiltration membrane organic separation device.

5. The wastewater treatment system of claim 4, wherein the first roll-to-roll ultrafiltration or nanofiltration membrane organic separation device has a molecular weight cut-off of one of 10000Da, 8000Da, 5000Da, 3000Da, 2500Da, 1000Da, and the second roll-to-roll ultrafiltration or nanofiltration membrane organic separation device has a molecular weight cut-off of one of 2500Da, 1000Da,800Da, 600Da, 500Da,300Da,150 Da.

6. The wastewater treatment system of claim 1, wherein the membrane clarification unit (12) comprises a hollow fiber membrane filtration unit.

7. The wastewater treatment system according to claim 1, wherein the membrane separation device (3) comprises a roll-to-roll, butterfly or plate membrane nanofiltration device.

8. The wastewater treatment system according to claim 1, wherein the reverse osmosis filtration unit (4) comprises a first reverse osmosis membrane filtration device and a second reverse osmosis membrane filtration device.

9. The wastewater treatment system of claim 8, wherein the first reverse osmosis membrane filtration device has a molecular weight cut-off of one of 300Da,150Da, 100Da, 50Da, 30Da, and 10 Da.

10. The wastewater treatment system of claim 8 wherein the second reverse osmosis membrane filtration device has a filtration accuracy of one of 300Da,150Da, 100Da, 50Da, 30Da, and 10 Da.