Green carbon neutralization treatment method and system for concrete wastewater

Abstract

The invention provides a green carbon neutralization treatment method and system for concrete wastewater, and belongs to the technical field of sewage treatment.The treatment method comprises the following steps that S1, sand and stone separation is conducted, specifically, concrete cleaning slurry is subjected to settling to separate out sand and stone, and primary slurry is obtained; s2, filtering: performing solid-liquid separation on the primary slurry obtained in S1 to obtain secondary filtrate; S3, neutralizing with organic acid: adding the organic acid into the secondary filtrate obtained in S2 to adjust the pH value to a preset value; s4, aeration neutralization: carrying out aeration neutralization on the filtered water treated in S3 until the pH value of the filtrate reaches the emission standard; the aeration gas is selected from any one or more of air and industrial waste gas containing CO2. In addition, the invention further provides a system suitable for the method, organic acid neutralization and aeration neutralization are combined, and a concrete wastewater treatment solution which is efficient, low in cost, stable in treatment effect and easy and convenient to operate is provided.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to a green carbon neutralization treatment method and system for concrete wastewater. Background Art

[0002] In the field of cement mixing plants and construction projects, the importance of wastewater treatment is becoming increasingly prominent. The wastewater from the washing of cement mixing trucks and the wastewater generated by the separation of waste concrete from the mixing plant in the construction project are both highly alkaline, with a pH value of 12.5-13, and high solid and soluble content. If they are discharged directly without effective treatment, they will cause serious pollution to soil and groundwater resources, damage the ecological environment, and lead to waste of resources. At present, there are some technical means for the treatment of cement mixing plant wastewater and construction project-related wastewater. In the pretreatment stage, large particles of sand and gravel are often separated by a sand and gravel separator, and then fine particles are precipitated in a sedimentation tank, and finally a filter press is used to achieve solid-liquid separation. The insoluble matter is filtered out to become a filter cake for roadbed backfill, while the soluble pollutants enter the raw water pool with the filtrate. However, these treated filter press waters cannot be used or discharged directly. The large backlog not only brings treatment difficulties to enterprises, but also causes harm to the environment due to long-term accumulation.

[0003] For alkaline raw water after filter pressing, the existing treatment technologies mainly include traditional reagent neutralization method and atomized carbon dioxide neutralization method. Traditional reagent neutralization method mostly uses oxalic acid and other reagents for pH neutralization reaction. Although it can precipitate calcium ions and neutralize hydroxide ions, it has the problem of difficult endpoint control. Oxalic acid is very easy to be excessive, resulting in acidic water quality after treatment, and the excess oxalic acid needs to be treated additionally, which not only increases the treatment cost, but also makes the treatment process more complicated; although the atomized carbon dioxide neutralization method can achieve sewage neutralization, the preparation of its raw material carbon dioxide needs to be compressed into liquid first, and then converted into gas phase and introduced into wastewater for neutralization. This method is costly, involving compression, storage, transportation and other links, and consumes a lot of energy. In addition, during the treatment process, if the amount of carbon dioxide introduced is not properly controlled, the precipitate will be redissolved, which seriously affects the treatment effect and reduces the stability and reliability of wastewater treatment.

[0004] Therefore, there is an urgent need for a concrete wastewater treatment solution that is efficient, low-cost, has stable treatment effects, and is easy to operate. Summary of the invention

[0005] The purpose of this application is to provide a green carbon neutralization treatment method and system for concrete wastewater to solve the above-mentioned problems existing in the prior art.

[0006] The embodiments of the present application can be implemented through the following technical solutions:

[0007] A green carbon neutralization treatment method for concrete wastewater comprises the following steps:

[0008] S1. Sand and gravel separation: The concrete cleaning slurry is subjected to sedimentation to separate the sand and gravel to obtain a primary slurry;

[0009] S2, filtration: performing solid-liquid separation on the primary slurry obtained in S1 to obtain a secondary filtrate;

[0010] S3, organic acid neutralization: adding organic acid to the secondary filtrate obtained in S2 to adjust the pH value to a preset value;

[0011] S4, aeration and neutralization: aeration and neutralization of the filtered water after S3 treatment until the pH value of the filtrate reaches the discharge standard; the aeration gas is selected from any one or more of air and industrial waste gas containing CO2.

[0012] Furthermore, the preset value of the pH value in S3 is 9-12.

[0013] Furthermore, the organic acid in S3 is oxalic acid.

[0014] Furthermore, the S1 sand and gravel separation specifically includes placing the concrete cleaning slurry in a cyclone sand settling tank for sedimentation to separate the sand and gravel, thereby obtaining a primary slurry.

[0015] Furthermore, the S2 filtration specifically includes filter pressing and re-filtration. The filter pressing refers to pumping the primary slurry obtained in S1 into a slurry filter press for filter pressing to obtain filter cake and filtrate; the re-filtration refers to sending the filtrate obtained by filter pressing into a sand filter tank for re-filtration to obtain a secondary filtrate.

[0016] Furthermore, the S4 aeration neutralization specifically includes conveying the filtered water after S3 treatment to a neutralization tank, and the neutralization tank is provided with an aeration fan system, through which sufficient aeration is performed to allow CO2 in the air or industrial waste gas to react with the filtered water for neutralization.

[0017] A system suitable for any of the above-mentioned treatment methods comprises a cyclone sand settling tank, a sewage storage tank, a sewage pump, a slurry filter press, a sand filter tank, an organic acid neutralization tank and a neutralization tank connected in series in sequence, wherein the neutralization tank is provided with an aeration fan system.

[0018] Furthermore, the aeration fan system includes a fan and an aeration head, the aeration head is a microporous aeration head, the aeration head is evenly arranged at the bottom of the neutralization tank, and the outlet pressure of the aeration head is not less than 23 kPa.

[0019] Furthermore, the sand filter tank is connected to a clean water tank through a backwash pump, and clean water in the clean water tank is pumped into the sand filter tank through the backwash pump to backwash it; the sand filter tank is connected to a sewage storage tank, and the sewage after backwashing flows into the sewage storage tank for recycling;

[0020] And / or, the organic acid neutralization tank is connected to a slurry filter press to recover the precipitate generated by the neutralization of the organic acid.

[0021] A system suitable for any of the above-mentioned treatment methods comprises a cyclone sand settling tank, a sewage storage tank, a sewage pump, a slurry filter press, a sand filter tank and an integrated neutralization tank connected in series in sequence, wherein the integrated neutralization tank is provided with a stirring device, an organic acid dosing system, an aeration fan system, a pH monitoring and control system and a sedimentation collection and discharge device.

[0022] The green carbon neutralization treatment method and system for concrete wastewater provided in the embodiments of the present application have at least the following beneficial effects:

[0023] This application combines organic acid neutralization with aeration neutralization to accurately control the reaction process. By presetting the pH value of organic acid neutralization in an appropriate range, the organic acid fully neutralizes the alkaline substances, precipitates metal ions, and reduces the hardness of the water; aeration further neutralizes the wastewater, so that the pH value of the final filtrate is stable and meets the discharge standard, and the precipitate is not easy to dissolve again during the treatment process, ensuring stable water quality and reliable treatment effect;

[0024] Secondly, aeration neutralization is adopted, using air or industrial waste gas containing CO2, which not only reduces the pH value of wastewater, but also absorbs CO2, promoting the green development of enterprises;

[0025] In addition, the precipitate generated during the treatment process, such as calcium oxalate, can be recycled and the filter cake can be used for roadbed backfill, thus achieving resource recycling and creating economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a trend chart of the pH value and conductivity of the filtrate of Comparative Example 1 which is neutralized only by pure CO2 as a function of the CO2 introduction time;

[0027] FIG2( a) is a graph showing the pH value of the filtrate of Comparative Example 2 which is neutralized only by pure air as a function of the time of air introduction;

[0028] FIG2( b ) is an enlarged schematic diagram of the pH value and conductivity corresponding to the air-introducing time data in the dashed box in FIG2( a );

[0029] Figure 3 This is a trend chart of the pH value and conductivity of the filtrate of Comparative Example 3 which is neutralized only with pure oxalic acid as a function of the amount of oxalic acid added;

[0030] FIG4( a ) is a graph showing the pH value and conductivity of the filtrate as a function of the amount of oxalic acid added when the filtrate is first neutralized with oxalic acid in Example 1;

[0031] FIG4( b ) is a graph showing the pH value and conductivity of the filtrate as a function of the time of air introduction when the air is introduced for neutralization treatment after Example 1;

[0032] FIG5(a) is a graph showing the pH value and conductivity of the filtrate as a function of the amount of oxalic acid added when the filtrate is first neutralized with oxalic acid in Example 2;

[0033] FIG5( b ) is a graph showing the pH value of the filtrate changing with the time of air passing after air passing for neutralization treatment in Example 2;

[0034] Figure 6 This is a comparative schematic diagram of Examples 2, 3, and 4 in which oxalic acid is first added to neutralize the filtrate to different pH values ​​and then air is introduced;

[0035] Figure 7 A schematic diagram of a green carbon neutral treatment system for concrete wastewater provided for this application;

[0036] Numbers in the figure: 1-cyclone sand settling tank, 2-wastewater storage tank, 3-wastewater pump, 4-slurry filter press, 5-sand filter tank, 6-organic acid neutralization tank, 61-stirring device, 62-first pH meter, 7-organic acid storage tank, 8-neutralization tank, 81-aeration device, 82-second pH meter; DETAILED DESCRIPTION

[0037] The present application provides a green carbon neutralization treatment method for concrete wastewater, which comprises the following steps:

[0038] S1. Sand and gravel separation: The concrete cleaning slurry is subjected to sedimentation to separate the sand and gravel to obtain a primary slurry;

[0039] S2, filtration: The primary slurry obtained in S1 is subjected to solid-liquid separation to obtain a secondary filtrate:

[0040] S3, organic acid neutralization: adding organic acid to the secondary filtrate obtained in S2 to adjust the pH value to a preset value;

[0041] S4, aeration and neutralization: aeration and neutralization of the filtered water after S3 treatment until the pH value of the filtrate reaches the discharge standard; the aeration gas is selected from any one or more of air and industrial waste gas containing CO2.

[0042] Specifically, the S1 sand and gravel separation specifically includes placing the concrete cleaning slurry in a cyclone sand settling tank for sedimentation to separate the sand and gravel, and the obtained primary slurry is a slurry with high alkalinity and high solid content;

[0043] Specifically, the S2 filtration includes pumping the primary slurry obtained in S1 into a slurry filter press for filtration, wherein the separated insoluble matter is pressed into filter cake slag, which can be used for roadbed backfill, etc., and the obtained filtrate is used for subsequent neutralization treatment, and the filtrate is a high alkaline filtrate with a pH value of about 13; in some preferred embodiments, it also includes re-filtration, that is, the filtrate is sent to a sand filter tank for re-filtration again, so as to further process some residual fine solid particles, colloidal substances or other suspended matter, further purify the water quality, reduce the turbidity in the water, and improve the effect of subsequent neutralization treatment.

[0044] Specifically, the organic acid in S3 can be selected from oxalic acid, citric acid, tartaric acid, malic acid, etc. The organic acid can neutralize the alkaline substances in the concrete wastewater on the one hand, effectively reducing the pH value of the wastewater, and on the other hand react with some metal ions (such as Ca 2+ 、Al 3+ Mg 2+ etc.) to undergo complexation or precipitation reaction to reduce the hardness of water; preferably, the organic acid is oxalic acid;

[0045] Specifically, the preset pH value in S3 is 9 to 12. This range can better balance the reaction process and treatment cost while ensuring the treatment effect, avoiding resource waste and over-treatment; adjusting the pH value to 9-12 can effectively neutralize most alkaline substances, greatly reduce the alkalinity of wastewater, and reduce the pressure of subsequent treatment. At the same time, in this pH range, organic acids (such as oxalic acid) can react with Ca in wastewater. 2+ 、Al 3+ Mg 2+ The metal ions react fully to form precipitates or complexes, thereby reducing the hardness of water, reducing the metal ion content in water, and improving water quality. In addition, it avoids excessive organic acid that may be caused by adjusting the pH value too low, thereby increasing the subsequent treatment cost and difficulty. Preferably, the preset pH value is 10-11, and more preferably, the preset pH value is 10. At this time, the best balance can be achieved in neutralizing alkalinity, reducing hardness, and subsequent aeration neutralization. The organic acid reacts fully with the alkaline substances and metal ions, and the precipitation effect is ideal. At the same time, it provides the most suitable starting point for subsequent aeration.

[0046] Preferably, the precipitate generated after the neutralization of the S3 organic acid can be passed into a slurry filter press and subjected to filter pressure treatment together with the primary slurry. On the one hand, there is no need to set up additional separate precipitation treatment equipment and processes, thus reducing intermediate links; on the other hand, the resource recovery value of the entire treatment process is improved.

[0047] Specifically, the S4 aeration neutralization specifically includes conveying the filtered water after S3 treatment to a neutralization tank, and the neutralization tank is provided with an aeration fan system, through which sufficient aeration is performed to make CO2 in the air or industrial waste gas react with the high alkaline solution for neutralization.

[0048] Specifically, in some specific embodiments, the pH value of the filtrate in S4 reaching the discharge standard means that it meets the requirements of "GB / T31962-2015 Water Quality Standard for Sewage Discharge into Urban Sewers", that is, the pH value is in the range of 6.5 to 9.5.

[0049] Hereinafter, the present application will be further described based on preferred embodiments with reference to the accompanying drawings.

[0050] Source of raw materials: Raw water, i.e., waste water from concrete sites, obtained after sand and gravel separation and filter pressing. According to testing, the pH value of the raw water is 12.9-13.1; CO2 gas and oxalic acid are both standard products available on the market;

[0051] Comparative Example 1

[0052] 800 mL of raw water was placed in a beaker, and pure CO2 was introduced into the beaker at a flow rate of 2.5 mL / min. The pH value and conductivity of the filtrate after the raw water and CO2 were introduced for different times, such as 30 min, 45 min, 60 min, 70 min, 75 min, 80 min, 120 min, and 360 min, were tested. The results are shown in Table 1 and Figure 1 As shown;

[0053] It can be seen that with the increase of CO2 introduction time, the pH value of the filtrate shows a gradual downward trend, while the conductivity shows a trend of first decreasing and then increasing with the increase of introduction time; it is well known that the conductivity of a solution is positively correlated with its solid content, that is, with the increase of the solid particle content in the system, the conductivity of the solution is correspondingly enhanced; conversely, when the solid content decreases, the conductivity also decreases; the solid content of the filtrate after 75 minutes of CO2 introduction was tested, and the result was 2700 mg / L, and the solid content of the filtrate after 360 minutes of CO2 introduction was 3300 mg / L, which matches the experimental result of conductivity; that is, although the pH can be adjusted by using pure CO2 gas to neutralize the raw water, there is a problem with the precipitation of Ca ions, that is, with the increase of CO2 gas introduction time, the calcium oxalate precipitate that has been formed reacts and dissolves again.

[0054] Table 1

[0055] pH Conductivity / (ms / cm) Raw water 12.90 12.30 After 30 minutes of passing, the filtrate 12.61 8.01 After 45 minutes of passing, the filtrate 12.24 6.53 After 60 minutes of passing, the filtrate 11.86 5.01 After 70 minutes of passing, the filtrate 10.04 4.23 After 75 minutes of passing, the filtrate 9.19 4.16 After 80 minutes of filtration 8.48 4.35 After 120 minutes of filtration 7.32 4.77 After 360 minutes of filtrate 6.79 5.14

[0056] Comparative Example 2

[0057] 400 ml of raw water was placed in a beaker, and air was introduced into the beaker at a flow rate of 1.5 L / min. The pH value and conductivity of the filtrate after the air was introduced for different time periods were tested. The results are shown in Table 2 and Figure 2;

[0058] It can be seen that although the use of pure air to treat raw water can reduce the pH value of raw water to a certain extent and achieve a partial neutralization effect, its treatment efficiency is low and it takes a very long time to reach a certain degree of neutralization.

[0059] Table 2

[0060] pH Conductivity / (ms / cm) The filtrate after 22 hours of passage 11.26 4.16 The filtrate after 22h30min of passing 10.77 4.11 The filtrate after 23h10min of passing 10.23 4.12 The filtrate after 24 hours of passage 9.72 4.13

[0061] Comparative Example 3

[0062] Take 400ml of raw water in a beaker, add 20g / L oxalic acid solution into it, and test the pH value and conductivity of the filtrate with different oxalic acid addition amounts. The results are as follows: Figure 3 As shown;

[0063] As can be seen from the figure, the change in pH value with the amount of oxalic acid added is not a slow and even approach to neutrality, but a sudden change at around pH 11. Before the volume of oxalic acid added reaches 80 mL, the pH value is above 10, showing a strong alkalinity. When 81 mL is added, the pH value drops rapidly to 8.05. When 82 mL is added, the pH value drops sharply to 5.62, becoming acidic. This rapid change makes it difficult to accurately grasp the neutralization endpoint. Once a little more oxalic acid is added due to carelessness, the water quality will easily deviate from neutrality.

[0064] Example 1

[0065] 400 ml of raw water was taken into a beaker, and 20 g / L oxalic acid solution was gradually added thereto until the pH of the filtrate was reduced to 11.83 after 70 ml was added, and the pH value and conductivity of the filtrate were tested as a function of the amount of oxalic acid added, as shown in FIG4(a); air was then introduced into the filtrate at a flow rate of 1.5 L / min, and the pH value and conductivity of the filtrate were tested as a function of the air introduction time, as shown in FIG4(b);

[0066] As can be seen from the figure, after the pH value of the raw water is adjusted to 11.83 with oxalic acid, air is introduced at a flow rate of 1.5L / min, and it takes about 240 minutes to neutralize to a pH value of about 9; in terms of conductivity, with the continuous introduction of air, the conductivity is finally basically maintained at around 3ms / cm. Since the conductivity of the solution is positively correlated with its solid content, this means that the solid content in the solution remains stable, which further indicates that the precipitate produced during the neutralization process has not dissolved again. The solid matter content in the system is relatively stable during the treatment process, and the treatment effect has a certain stability, which is conducive to the subsequent further treatment and utilization of the wastewater, and avoids the problem of repeated changes in water quality due to the dissolution of the precipitate.

[0067] Example 2

[0068] Take 400 ml of raw water in a beaker, first add 15 ml of 100 g / L oxalic acid solution to adjust the pH of the filtrate to about 11.5, then add 20 g / L oxalic acid in small amounts until the pH of the filtrate reaches 10.08, and at the same time, the pH value and conductivity of the filtrate are tested as a function of the amount of oxalic acid added, as shown in Figure 5(a); then, air is introduced into the filtrate with a pH value of 10.08 at a flow rate of 1.5 L / min, and the pH value of the filtrate is tested as a function of the air introduction time, as shown in Figure 5(b); As can be seen from the figure, It can be seen that after the pH value of the raw water is adjusted to 10.08 with oxalic acid, and then air is introduced at a flow rate of 1.5L / min, it takes about 20 minutes to neutralize to a pH value of about 9, and only 45 minutes to neutralize to a pH value of about 8; and in terms of conductivity, its conductivity has been as low as 3.14ms / cm when treated with oxalic acid for neutralization, and the conductivity and solid content of the filtrate remain basically unchanged with the change of the subsequent air introduction time, that is, the Ca ions in the raw water have been precipitated during the oxalic acid treatment, and the subsequent air introduction only affects the pH value, and will not dissolve the precipitate again, thereby ensuring the stability of the treatment effect.

[0069] Embodiment 3, Embodiment 4

[0070] Referring to the method of Example 2, 400 ml of raw water was taken into a beaker, 15 ml of 100 g / L oxalic acid solution was first added thereto to adjust the pH of the filtrate to about 11.5, and then 20 g / L oxalic acid was added thereto in small amounts until the pH value of the filtrate reached 9.77 (Example 3) and 9.04 (Example 4), respectively. Subsequently, air was introduced into the filtrates with pH values ​​of 9.77 and 9.04, respectively, at a flow rate of 1.5 L / min, and the change of the pH value of the filtrate with the air introduction time was detected. Figure 6 The figure shows a schematic diagram comparing the changes of the pH value of the filtrate with the duration of airing when air is passed into the filtrate at different initial pH values ​​of the filtrate in Example 2, Example 3 and Example 4;

[0071] As can be seen from the figure, the solution with an initial pH value of 9.04 dropped to about pH 8 in about 12 minutes, the solution with an initial pH value of 9.77 dropped to this value in about 32 minutes, and the solution with an initial pH value of 10.08 dropped to about pH 8 in about 45 minutes; at the same time, with continuous air introduction, the pH values ​​of the three solutions stabilized after dropping to a certain level and did not become acidic, indicating that this method can effectively neutralize alkaline solutions and there is no problem of over-acidification.

[0072] This application also provides a green carbon neutralization treatment system for concrete wastewater, combined with Figure 7 As shown, the system includes a concrete cleaning water reuse pre-treatment process section and a concrete cleaning water neutralization process section, wherein the concrete cleaning water reuse pre-treatment process section includes a cyclone sand settling tank 1, a sewage storage tank 2, a sewage pump 3, a slurry filter press 4 and a sand filter tank 5 connected in series in sequence;

[0073] Specifically, the cyclone grit chamber 1 is used to perform preliminary sedimentation on the collected concrete cleaning slurry to separate sand and gravel, and the treated high-solid content alkaline wastewater flows into the sewage storage tank 2; the sewage storage tank 2 is connected to the cyclone grit chamber, and its main function is to store the sewage after sedimentation to provide a buffer for subsequent treatment; the slurry filter press 4 is connected to the sewage storage tank 2 through the sewage pump 3, and the sewage pump 3 pumps the high-solid content alkaline wastewater in the sewage storage tank 2 into the slurry filter press 4 for filtration to achieve solid-liquid separation, wherein the insoluble matter is pressed into filter cake slag, which can be used for roadbed backfilling, etc., and the filtrate enters the sand filter tank 5 for further filtration;

[0074] Preferably, the sand filter tank 5 is also connected to a clean water tank (not shown in the figure) through a backwash pump, and the clean water in the clean water tank is pumped into the sand filter tank 5 through the backwash pump to backwash it; preferably, the sand filter tank 5 is also connected to the sewage storage tank 2, and when the sand filter tank 5 needs to be cleaned, the sewage generated by the flushing is sent back to the sewage storage tank 2 and processed again together with the newly collected wastewater to achieve the recycling of water resources.

[0075] The concrete cleaning water neutralization treatment process section includes an organic acid neutralization tank 6 and a neutralization tank 8, wherein the input end of the organic acid neutralization tank 6 is connected to the filtrate output end of the sand filter tank 5, and the filtrate output end of the organic acid neutralization tank 6 is connected to the input end of the neutralization tank 8; the filtrate filtered by the sand filter tank 5 enters the organic acid neutralization tank to react with the organic acid for neutralization, and the filtered water treated by the organic acid neutralization tank 6 is aerated and neutralized in the neutralization tank;

[0076] Specifically, the organic acid neutralization tank 6 is connected to the organic acid storage tank 7, and a stirring device 61, a first pH meter 62 and a liquid level controller (not shown in the figure) are provided in the organic acid neutralization tank 6; preferably, the organic acid neutralization tank 6 is also connected to the slurry filter press 4, and the calcium oxalate precipitate produced by the neutralization of the organic acid and the filtrate is filtered and transported back to the slurry filter press 4, and is filtered together with the high-solid alkaline slurry to improve resource utilization and reduce waste emissions.

[0077] Specifically, the neutralization tank 8 is provided with an aeration device 81, a second pH meter 82 and a liquid level controller (not shown in the figure), and the aeration fan system 81 includes a fan and an aeration head. The fan is used to transport air or CO2-containing gas to the neutralization tank. The aeration head is arranged at the bottom of the neutralization tank 8. Preferably, the aeration heads are evenly distributed at the bottom of the neutralization tank 8. The aeration head is a microporous aeration head, and the outlet pressure of the aeration head is not less than 23 kPa, so as to increase the gas-liquid contact area, improve the reaction efficiency of CO2 in the gas and the alkaline substances in the filtrate, and promote the aeration neutralization effect.

[0078] In some optional embodiments, the organic acid neutralization tank 6 and the neutralization tank 8 can also be of integrated design, that is, an integrated neutralization tank integrating the organic acid neutralization function and the aeration neutralization function to simplify the treatment process; specifically, the integrated neutralization tank is provided with a stirring device, an organic acid dosing system, an aeration fan system, a pH monitoring and control system, and a sedimentation collection and discharge device.

[0079] In the description of the embodiments of the present application, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. appear to indicate an orientation or position relationship, it is based on the orientation or position relationship shown in the accompanying drawings, or is the orientation or position relationship in which the products of the embodiments of the present application are usually placed when used. It is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0080] The vocabulary in this specification is used to illustrate the embodiments of the present application, but is not intended to limit the present application. It should also be noted that, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, an indirect connection through an intermediate medium, or a connection between the two elements. For those skilled in the art, the specific meanings of the above terms in this application can be specifically understood.

[0081] The above is a detailed introduction to the specific implementation methods of the present application. For those skilled in the art, several improvements and modifications may be made to the present application without departing from the principles of the present application. These improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A green carbon neutralization treatment method for concrete wastewater, characterized in that: The following steps are involved: S1. Sand and gravel separation: The concrete cleaning slurry is subjected to sedimentation to separate the sand and gravel to obtain a primary slurry; S2, filtration: performing solid-liquid separation on the primary slurry obtained in S1 to obtain a secondary filtrate; S3, organic acid neutralization: adding organic acid to the secondary filtrate obtained in S2 to adjust the pH value to a preset value; S4, aeration and neutralization: aeration and neutralization of the filtered water after S3 treatment until the pH value of the filtrate reaches the discharge standard; the aeration gas is selected from any one or more of air and industrial waste gas containing CO2.

2. The processing method according to claim 1, characterized in that: The preset value of the pH value in S3 is 9-12.

3. The processing method according to claim 2, characterized in that: The organic acid in S3 is oxalic acid.

4. The processing method according to claim 1, characterized in that: The S1 sand and gravel separation specifically includes placing the concrete cleaning slurry in a cyclone sand settling tank for sedimentation to separate the sand and gravel, thereby obtaining a primary slurry.

5. The processing method according to claim 1, characterized in that: The S2 filtration specifically includes filter pressing and re-filtration. The filter pressing refers to pumping the primary slurry obtained in S1 into a slurry filter press for filter pressing to obtain filter cake and filtrate; the re-filtration refers to sending the filtrate obtained by filter pressing into a sand filter tank for re-filtration to obtain a secondary filtrate.

6. The processing method according to claim 1, characterized in that: The S4 aeration neutralization specifically includes conveying the filtered water after S3 treatment to a neutralization tank, wherein the neutralization tank is provided with an aeration fan system, and the aeration fan system is used to fully aerate the CO2 in the air or industrial waste gas to react with the filtered water for neutralization.

7. A system suitable for the treatment method according to any one of claims 1 to 6, characterized in that: The invention comprises a cyclone sand settling tank (1), a sewage storage tank (2), a sewage pump (3), a slurry filter press (4), a sand filter tank (5), an organic acid neutralization tank (6) and a neutralization tank (8) which are sequentially connected in series, wherein the neutralization tank (8) is provided with an aeration fan system (81).

8. The system according to claim 7, characterized in that The aeration fan system (81) comprises a fan and an aeration head. The aeration head is a microporous aeration head. The aeration head is evenly arranged at the bottom of the neutralization tank (8). The outlet pressure of the aeration head is not less than 23 kPa.

9. The system according to claim 7, characterized in that The sand filter tank (5) is connected to a clean water tank via a backwash pump, and clean water in the clean water tank is pumped into the sand filter tank (5) via the backwash pump to backwash the sand filter tank; the sand filter tank (5) is connected to a sewage storage tank (2), and the sewage after backwashing flows into the sewage storage tank (2) for recycling; And / or, the organic acid neutralization tank (6) is connected to the slurry filter press (4) to recover the precipitate generated by the neutralization of the organic acid.

10. A system suitable for the treatment method according to any one of claims 1 to 6, characterized in that: The invention comprises a cyclone sand settling tank (1), a sewage storage tank (2), a sewage pump (3), a slurry filter press (4), a sand filter tank (5) and an integrated neutralization tank which are sequentially connected in series. The integrated neutralization tank is provided with a stirring device, an organic acid dosing system, an aeration fan system, a pH monitoring and control system and a sedimentation collection and discharge device.

Images