System and method for dechlorinating leachate reverse osmosis effluent

Abstract

The invention relates to the technical field of wastewater treatment, and discloses a leachate reverse osmosis effluent dechlorination system which comprises a Cl <->-ISE sensor and a dechlorination reaction subsystem which are connected in sequence, the Cl <->-ISE sensor is connected with a water inlet device, and the dechlorination reaction subsystem comprises a reactor main body, the water inlet device, a centrifugal device, a pH adjusting device and an effluent device which are connected in sequence. The reactor main body is connected with a Cl <->-ISE sensor; the water inlet device introduces reverse osmosis effluent into the reactor main body, calcium oxide and sodium metaaluminate are added for mixing to form a solid-liquid mixture, the solid-liquid mixture is separated by the centrifugal device, supernate is neutralized by the pH adjusting device, and finally, effluent reaching the standard is discharged by the water outlet device. According to the method, by optimizing parameters, the high chloride ion removal rate is achieved, the standard of reuse of reclaimed water is achieved while chloride ions in the reverse osmosis effluent of the leachate of the waste treatment plant are efficiently removed, and the purposes of deep treatment and resource utilization of the reverse osmosis effluent of the leachate of the waste treatment plant are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and in particular to a system and method for removing chlorine from leachate reverse osmosis effluent. Background Art

[0002] Research has shown that only a small portion of the recycled water generated by reverse osmosis in the leachate industry is reused internally. The majority is discharged into natural water bodies within local emission standards, utilizing the ecological environment for deep purification. my country's per capita freshwater resources are far below the global average, and freshwater resources are relatively scarce. Therefore, water resource recycling is crucial for my country. Chloride ions, a common corrosive anion, can lead to corrosion of industrial equipment and pipelines, soil salinization, impact plant and animal growth, and even harm human health when chloride ion concentrations in water are too high. Therefore, removing chloride ions from leachate reverse osmosis effluent and achieving efficient resource reuse of leachate reverse osmosis effluent is of great practical significance. Summary of the Invention

[0003] The present invention provides a system and method for removing chlorine from leachate reverse osmosis effluent. Based on real-time monitoring of Cl- and with chemical precipitation-centrifugal separation as the core, the system removes chlorine from leachate reverse osmosis effluent, thereby solving the problem of removing chloride ions from leachate reverse osmosis effluent in garbage treatment plants.

[0004] The present invention provides a system for dechlorinating leachate reverse osmosis effluent, comprising a Cl--ISE sensor and a dechlorination reaction subsystem connected in sequence, wherein the Cl--ISE sensor is connected to a water inlet device, and the dechlorination reaction subsystem comprises a reactor body, a water inlet device, a centrifugal device, a pH adjustment device and a water outlet device connected in sequence, wherein the reactor body is connected to the Cl--ISE sensor;

[0005] The water inlet device introduces the reverse osmosis effluent into the reactor body, and adds calcium oxide and sodium aluminate to mix to form a solid-liquid mixture. The solid-liquid mixture is separated by the centrifugal device, and the supernatant is neutralized by the pH adjustment device, and finally the qualified effluent is discharged by the water outlet device.

[0006] Furthermore, the Cl--ISE sensor is used to monitor the chloride ion concentration of the inlet water of the water inlet device in real time.

[0007] Furthermore, an agitator and a heater are provided in the reactor body. After the reverse osmosis effluent is introduced into the reactor body, the calcium oxide is added first and then the sodium aluminate is added to react. The heater controls the reaction temperature and the agitator promotes mixing of the reactants.

[0008] Furthermore, the water outlet end of the reactor body is connected to the centrifugal device to separate the solid-liquid mixture produced by the reaction of the reactor body, and the supernatant produced by centrifugation of the centrifugal device enters the pH adjustment device for treatment.

[0009] The present invention also provides a method for dechlorinating leachate reverse osmosis effluent. Based on the system for dechlorinating leachate reverse osmosis effluent as described above, the method specifically comprises:

[0010] S1, the water inlet device transports the leachate reverse osmosis effluent to the reactor body, and turns on the heater to adjust the reaction temperature;

[0011] S2. Calculate the amount of CaO added based on the real-time monitoring of chloride ion concentration data by the Cl--ISE sensor, turn on the stirrer, and dissolve at 20° C. for half an hour;

[0012] S3, according to the real-time monitoring of chloride ion concentration data by the Cl--ISE sensor, calculate the addition of NaAlO2, and react for 4 hours under stirring and heating conditions;

[0013] S4, after the reaction is completed, the product is transported to the centrifugal device for centrifugation to separate the solid-liquid mixture;

[0014] S5. After the centrifugation is completed, the supernatant is transferred to the pH adjustment device, and CH3COOH is used to adjust the pH of the supernatant to between 6.5 and 7.5 according to the monitoring data of the pH meter to neutralize the excess hydroxide ions generated by the reaction;

[0015] S6. The supernatant after pH adjustment is transported to the water outlet device through the water outlet end of the pH adjustment device.

[0016] Furthermore, in step S1, the heater is turned on to adjust the temperature to 20° C. so that the inlet water temperature is maintained at the optimal temperature for the dechlorination reaction.

[0017] Furthermore, in step S2, the dosage of CaO is controlled so that the ratio of Ca to Cl is 18:1, which is the optimal ratio for the dechlorination reaction.

[0018] Furthermore, in step S3, the dosage of NaAlO2 is controlled so that the ratio of Al to Cl is 6:1, which is the optimal ratio for dechlorination reaction.

[0019] Furthermore, the ratio of added CaO and NaAlO2 to chloride ion concentration in effluent was fixed at 18:6:1 as the optimal ratio for chlorine removal from leachate reverse osmosis effluent.

[0020] The beneficial effects of the present invention are:

[0021] 1. The present invention is based on real-time monitoring of Cl-, with chemical precipitation-centrifugal separation as the core, to remove chlorine from the leachate reverse osmosis effluent. By real-time monitoring of chloride ion concentration data, dynamic dosing control, precise reaction temperature and dosing ratio are achieved, thereby improving the dechlorination efficiency of the leachate reverse osmosis effluent. While achieving efficient removal of chloride ions in the reverse osmosis effluent of the leachate from the waste treatment plant, the purpose of reclaimed water reuse is achieved, and the deep treatment and resource utilization of the reverse osmosis effluent of the leachate from the waste treatment plant is realized.

[0022] 2. The present invention constructs a dechlorination reaction subsystem consisting of a reactor body, a centrifugal device, a pH adjustment device, and a water outlet device. The main reactor is equipped with an agitator and a heater. By real-time monitoring of the chloride ion concentration of the influent, the operating conditions and drug dosage of the leachate reverse osmosis effluent dechlorination reaction are adjusted. Simultaneously, chemical precipitation, solid-liquid separation, and pH adjustment are coupled, resulting in high dechlorination efficiency and strong adjustability, bringing significant social, economic, and environmental benefits.

[0023] 3. After the chloride ion concentration in the leachate reverse osmosis effluent is reduced to below the reclaimed water reuse standard, the chloride ions react with the CaO and NaAlO2 dissolved in water to form Ca4Al2Cl2(OH) 12 , and is removed after centrifugation by a centrifugal device. The supernatant produced after centrifugation is adjusted to a pH between 6.5 and 7.5 by a pH regulating device, reaching the standard for reclaimed water reuse, realizing the deep treatment and resource utilization of the reverse osmosis effluent of the leachate from the garbage treatment plant, reducing the operating costs of the leachate company and the reclaimed water receiving units in the park, and improving the level of refined management, which is of great significance to responding to my country's "sustainable development" strategy. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic structural diagram of the system for dechlorination of leachate reverse osmosis effluent according to the present invention.

[0025] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of the application are only for the purpose of describing specific embodiments and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, not to describe a specific order.

[0027] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0028] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0029] The calcium aluminum salt precipitation method, also known as the Freund's salt method, is the most widely used chemical precipitation method. The calcium aluminum salt co-precipitation method is simple to operate, low in cost, has low pollution and high removal rate, and is widely used in industrial wastewater treatment. The calcium source raw material used in the present invention is calcium oxide, and the aluminum source raw material is sodium metaaluminate. These two materials will react with the chloride ions in the wastewater to form Freund's salt precipitate. The specific reaction process of the entire calcium aluminum salt precipitation method is as follows:

[0030] CaO+H2O→Ca(OH)2 (1)

[0031] NaAlO2+2H2O→Al(OH)3+Na + +OH - (2)

[0032] 4Ca(OH)2+2Al(OH)3→Ca4Al2(OH) 14 ↓ (3)

[0033] Ca4Al2(OH) 14 +2Cl - →Ca4Al2Cl2(OH) 12 ↓+2OH - (4)

[0034] CaO and NaAlO2 react with water to form Ca(OH)2 and Al(OH)3 respectively, and then the two continue to react in an alkaline environment to form Ca4Al2(OH) 14 , while Ca4Al2(OH) 14 The equilibrium constant of precipitation is 1×10 -25 , is insoluble in water and can react with Cl in water - The reaction generates a calcium chloroaluminate precipitate with a smaller precipitation equilibrium constant, namely Ca4Al2Cl2(OH) 12 .

[0035] The present invention provides a method and system for dechlorination of leachate reverse osmosis effluent based on real-time Cl- monitoring and chemical precipitation-centrifugal separation as the core. By optimizing parameters, a high chloride ion removal rate is achieved. The pH value of the supernatant after centrifugal separation is precisely controlled to complete neutralization treatment. While efficiently removing chloride ions from the reverse osmosis effluent of leachate from a waste treatment plant, the standard for reclaimed water reuse is met, thereby achieving the purpose of deep treatment and resource utilization of the reverse osmosis effluent of the leachate from the waste treatment plant.

[0036] In order to solve the technical problem of how to achieve efficient resource reuse of leachate reverse osmosis effluent from garbage treatment plants, the present invention provides a system and method for dechlorination of leachate reverse osmosis effluent, including: constructing a dechlorination reaction subsystem, which consists of a Cl--ISE sensor, a reactor body, a centrifugal device, a pH adjustment device and a water outlet device. The reactor body is provided with an agitator and a heater. After the reclaimed water enters the reactor body, calcium oxide and sodium aluminate are successively added, and the temperature is adjusted to fully stir the reaction. The solid-liquid mixture generated by the reaction enters the centrifugal device for centrifugation, and the separated supernatant is neutralized by the pH adjustment device, and the final effluent meets the reuse standard. The specific structure of the system is as follows Figure 1 As shown:

[0037] The present invention provides a system for dechlorinating leachate reverse osmosis effluent, comprising a Cl--ISE sensor and a dechlorination reaction subsystem connected in sequence, wherein the Cl--ISE sensor is connected to a water inlet device, and the dechlorination reaction subsystem comprises a reactor body, a water inlet device, a centrifugal device, a pH adjustment device and a water outlet device connected in sequence, wherein the reactor body is connected to the Cl--ISE sensor;

[0038] The reactor body is provided with an agitator and a heater. The water inlet device introduces reverse osmosis effluent into the reactor body, and calcium oxide and sodium aluminate are added successively for reaction. The heater controls the reaction temperature, and the agitator promotes mixing of reactants. The solid-liquid mixture formed after the reaction is completed is separated by the centrifugal device. The pH adjustment device is provided with an agitator and a pH meter. The supernatant after centrifugal separation of the solid-liquid mixture is neutralized by the pH adjustment device, and finally the qualified effluent is discharged by the water outlet device.

[0039] The reactor body is equipped with a temperature regulating device and a stirring device for regulating the reaction temperature and promoting drug dissolution. The water outlet of the reactor body is connected to a centrifugal device. The solid-liquid mixture produced after the reaction is separated into solid and liquid by the centrifugal device. The supernatant water outlet of the centrifugal device is connected to a pH regulating device. The pH regulating device is equipped with a pH meter and a stirring device for real-time monitoring of the pH value of the water outlet and promoting pH regulation.

[0040] In one embodiment, the Cl--ISE sensor is used to monitor the chloride ion concentration of the water inlet device in real time. The reactor body is provided with a stirring device and a heating device for realizing chemical reaction and temperature control; the centrifugal device is used to separate the solid-liquid mixture generated by the reaction; and the pH adjustment device is used to neutralize the supernatant after separation.

[0041] In one embodiment, the water inlet is equipped with a Cl-ISE sensor and connected to the reactor body. The reactor body is equipped with an agitator and heater. CaO and NaAlO2 are added sequentially, and heating and stirring promote the reaction. The water outlet is connected to a centrifugal device to separate the solid-liquid mixture produced by the reaction. The supernatant produced by centrifugation enters a pH adjustment device for treatment, which is connected to the water outlet.

[0042] The present invention also provides a method for dechlorinating leachate reverse osmosis effluent. Based on the system for dechlorinating leachate reverse osmosis effluent as described above, the method specifically comprises:

[0043] S1. The water inlet device transports the leachate reverse osmosis effluent to the reactor body, and turns on the heater to adjust the reaction temperature to 20° C. to maintain the water inlet temperature at the optimal temperature for dechlorination reaction.

[0044] S2. According to the real-time monitoring of chloride ion concentration data by the Cl--ISE sensor, CaO is added with a Ca:Cl ratio of 18:1, and the stirrer is turned on to dissolve the mixture at 20°C for half an hour; the amount of CaO added is controlled so that the ratio of Ca to Cl is the optimal ratio of 18:1 for dechlorination reaction.

[0045] S3. According to the real-time monitoring of chloride ion concentration data by the Cl--ISE sensor, NaAlO2 is added with an Al:Cl ratio of 6:1, and the reaction is carried out for 4 hours under stirring and heating conditions; the dosage of NaAlO2 is controlled so that the ratio of Al to Cl is the optimal ratio of 6:1 for dechlorination reaction.

[0046] S4, after the reaction is completed, the product is transported to the centrifugal device for centrifugation to separate the solid-liquid mixture;

[0047] S5. After the centrifugation is completed, the supernatant is transferred to the pH adjustment device, and CH3COOH is used to adjust the pH of the supernatant to between 6.5 and 7.5 according to the monitoring data of the pH meter to neutralize the excess hydroxide ions generated by the reaction;

[0048] S6. The supernatant after pH adjustment is transported to the water outlet device through the water outlet end of the pH adjustment device.

[0049] In one embodiment, a Cl-ISE sensor is connected to the reactor body to monitor the chloride ion concentration of the influent in real time, facilitating the addition of a fixed amount of CaO and NaAlO2 to the reactor body in steps S2 and S3. The reactor body is equipped with a stirring device to promote the dissolution of CaO and NaAlO2. The reactor body is also equipped with a heating device to adjust the temperature to the optimal reaction temperature of 20°C.

[0050] In one embodiment, the ratio of the added CaO and NaAlO2 to the chloride ion concentration in the effluent is fixed at 18:6:1, which is the optimal ratio for dechlorination of the leachate reverse osmosis effluent.

[0051] The specific implementation cases are as follows:

[0052] Leachate reverse osmosis effluent is obtained from landfill leachate generated by waste treatment plants through reverse osmosis treatment. Chlorine removal from leachate reverse osmosis effluent occurs in four stages.

[0053] In the first stage, the inlet valve is opened, allowing the leachate reverse osmosis effluent to flow through the Cl-ISE sensor and into the reactor body. The reactor body's temperature control is set to 20°C. The CaO and NaAlO2 dosages are precisely adjusted based on the inlet chloride ion concentration, as monitored in real time by the Cl-ISE sensor. The Ca:Al:Cl ratio is maintained at 18:6:1. When the inlet water temperature reaches 20°C, CaO is added. The reactor body's agitator is activated, accelerating dissolution for 30 minutes. Then, NaAlO2 is added, and the reaction continues for 240 minutes.

[0054] In the second stage, the outlet valve of the reactor body is opened and the solid-liquid mixture obtained after the reaction is transported to a centrifugal device for solid-liquid separation.

[0055] In the third stage, the supernatant outlet valve of the centrifugal device is opened, and the supernatant is transported to the pH adjustment device. The pH of the supernatant is monitored in real time according to the pH meter. The agitator of the pH adjustment device is turned on, and CH3COOH is used to adjust the pH of the supernatant to between 6.5 and 7.5.

[0056] In the fourth stage, the outlet valve of the pH adjustment device is opened to transport the treated leachate reverse osmosis effluent to the park for resource utilization.

[0057] The present invention utilizes a leachate reverse osmosis effluent dechlorination system, centered around chemical precipitation and centrifugal separation. The system primarily comprises a Cl-ISE sensor, a reactor body, a centrifugal device, and a pH adjustment device. The Cl-ISE sensor is connected to the reactor body's water inlet to monitor the chloride ion concentration in the influent in real time. CaO and NaAlO2 are added to the system to co-precipitate with the chloride ions in the influent, thereby reducing the chloride ion concentration.

[0058] Matters not covered by the present invention are known technologies.

[0059] It should be noted that for the aforementioned embodiments, for simplicity of description, they are all expressed as a series of action combinations. However, those skilled in the art should be aware that the present invention is not limited by the order of the actions described, because according to the present invention, certain steps may be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in this specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0060] In the several embodiments provided in this application, it should be understood that the disclosed devices can be implemented in other ways. For example, the device embodiments described above are merely illustrative, such as the division of the above-mentioned units. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the coupling or communication connection between each other shown or discussed can be through some interfaces, and the indirect coupling or communication connection between devices or units can be in the form of telecommunications or other forms.

[0061] The units described above as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0062] As used herein, the terms "comprises," "comprising," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, apparatus, article, or method that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, apparatus, article, or method. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of additional identical elements in the process, apparatus, article, or method that includes the element.

[0063] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A system for removing chlorine from leachate reverse osmosis effluent, characterized in that: It includes a Cl--ISE sensor and a dechlorination reaction subsystem connected in sequence, wherein the Cl--ISE sensor is connected to a water inlet device, and the dechlorination reaction subsystem includes a reactor body, a water inlet device, a centrifugal device, a pH adjustment device and a water outlet device connected in sequence, and the reactor body is connected to the Cl--ISE sensor; The water inlet device introduces the reverse osmosis effluent into the reactor body, and adds calcium oxide and sodium aluminate to mix to form a solid-liquid mixture. The solid-liquid mixture is separated by the centrifugal device, and the supernatant is neutralized by the pH adjustment device, and finally the qualified effluent is discharged by the water outlet device.

2. The system for dechlorination of leachate reverse osmosis effluent according to claim 1, characterized in that: The Cl--ISE sensor is used to monitor the chloride ion concentration of the inlet water of the water inlet device in real time.

3. The system for dechlorination of leachate reverse osmosis effluent according to claim 1, characterized in that: The reactor body is provided with an agitator and a heater. After the reverse osmosis effluent is introduced into the reactor body, the calcium oxide is first added and then the sodium aluminate is added to react. The heater controls the reaction temperature and the agitator promotes mixing of the reactants.

4. The system for dechlorination of leachate reverse osmosis effluent according to claim 1, characterized in that: The water outlet end of the reactor body is connected to the centrifugal device to separate the solid-liquid mixture produced by the reaction of the reactor body. The supernatant produced by centrifugation of the centrifugal device enters the pH regulating device for treatment.

5. A method for dechlorination of leachate reverse osmosis effluent, characterized in that: The system for dechlorination of leachate reverse osmosis effluent according to any one of claims 1 to 4, the method specifically comprising: S1, the water inlet device transports the leachate reverse osmosis effluent to the reactor body, and turns on the heater to adjust the reaction temperature; S2. Calculate the amount of CaO added based on the real-time monitoring of chloride ion concentration data by the Cl--ISE sensor, turn on the stirrer, and dissolve at 20° C. for half an hour; S3, according to the real-time monitoring of chloride ion concentration data by the Cl--ISE sensor, calculate the addition of NaAlO2, and react for 4 hours under stirring and heating conditions; S4, after the reaction is completed, the product is transported to the centrifugal device for centrifugation to separate the solid-liquid mixture; S5. After the centrifugation is completed, the supernatant is transferred to the pH adjustment device, and CH3COOH is used to adjust the pH of the supernatant to between 6.5 and 7.5 according to the monitoring data of the pH meter to neutralize the excess hydroxide ions generated by the reaction; S6. The supernatant after pH adjustment is transported to the water outlet device through the water outlet end of the pH adjustment device.

6. The method for dechlorination of leachate reverse osmosis effluent according to claim 5, characterized in that: In step S1, the heater is turned on to adjust the temperature to 20° C. so that the inlet water temperature is maintained at the optimal temperature for the dechlorination reaction.

7. The method for dechlorination of leachate reverse osmosis effluent according to claim 5, characterized in that: In step S2, the dosage of CaO is controlled so that the ratio of Ca to Cl is 18:1, which is the optimal ratio for the dechlorination reaction.

8. The method for dechlorination of leachate reverse osmosis effluent according to claim 5, characterized in that: In step S3, the dosage of NaAlO2 is controlled so that the ratio of Al to Cl is 6:1, which is the optimal ratio for the dechlorination reaction.

9. The method for dechlorination of leachate reverse osmosis effluent according to claim 5, characterized in that: The ratio of added CaO and NaAlO2 to chloride ion concentration in effluent was fixed at 18:6:1, which was taken as the optimal ratio for dechlorination of leachate reverse osmosis effluent.

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