A method and system for treating high-salinity organic wastewater

Abstract

The application provides a high-salt organic wastewater treatment method and system, which comprises the following steps: high-salt organic wastewater to be treated enters a biochemical treatment system; water produced by the biochemical treatment system enters an electrolytic oxidation system; water produced by the electrolytic oxidation system enters a sludge contact reactor, and reacts with sludge added into the sludge contact reactor; sludge produced by the sludge contact reactor is sent into a sludge concentration tank; and water produced by the sludge contact reactor is directly used for steel slag hot braising or directly sent into a membrane filtration system for subsequent treatment. The high-salt organic wastewater treatment method and system can reduce the residual oxidizability of electrolytic oxidation water at a lower cost, the residual chlorine content of system water does not exceed the standard, the system water can be directly reused, the sludge is promoted to remove internal water, and the sludge dewatering efficiency is improved; the sludge flow is real-time regulated, the problem of inaccurate reaction regulation and control of the sludge contact reactor is solved, and the sludge flow and operation cost can be accurately controlled.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water treatment, in particular to a treatment method and system for high-salt organic wastewater. BACKGROUND

[0002] Electrolytic oxidation is a kind of advanced oxidation technology for degrading organic matter and ammonia nitrogen in water at present, which has high organic matter degradation efficiency and wide organic matter degradation capacity. In the practical engineering application of electrolytic treatment of high-salt organic wastewater, while degrading organic matter by electrolytic oxidation, the product usually presents excessive oxidation, such as high oxidation-reduction potential and high residual chlorine content, which is not conducive to the treatment of subsequent equipment. At present, the commonly used technical means is to add excessive reducing agent after electrolysis to ensure the safety of subsequent treatment equipment such as membrane filtration, adsorption resin and ion exchange resin. However, the cost of adding a large amount of reducing agent is high, and more ions are introduced into the wastewater, which increases the burden of subsequent wastewater concentration. Therefore, it is urgent to find a more cost-effective treatment method. SUMMARY

[0003] Based on the problems existing in the prior art, the present application provides a treatment method and system for high-salt organic wastewater, which realizes the purpose of in-situ treatment and direct reuse of high-salt organic wastewater.

[0004] The above-mentioned purpose is achieved by the following scheme:

[0005] A treatment method for high-salt organic wastewater, characterized in that the method comprises the following steps:

[0006] (1) the high-salt organic wastewater to be treated enters a biochemical treatment system;

[0007] (2) the water produced by the biochemical treatment system enters an electrolytic oxidation system;

[0008] (3) the water produced by the electrolytic oxidation system enters a sludge contact reactor, reacts with the sludge added to the sludge contact reactor, the sludge produced by the sludge contact reactor is sent to a sludge concentration tank, and the water produced by the sludge contact reactor is directly used for steel slag hot braising, or sent to a membrane filtration system and / or an adsorption resin system and / or an ion exchange resin system for subsequent treatment.

[0009] The method described above, characterized in that the sludge used in step (3) is the sludge produced by the biochemical treatment system.

[0010] The method described above, characterized in that the flow rate F of the sludge added to the sludge contact reactor in step (3) is determined according to the following formula: s1 Determined as follows:

[0011] First, set the sludge flow rate estimate value:

[0012] wherein F S is the sludge flow rate prediction value, F W is the influent flow rate, C I is the influent residual chlorine content, C O is the effluent residual chlorine content control value, C S is the sludge concentration, a1 is an empirical value of the proportion of organic components in the sludge, and the default value is 0.25, and w1 is an effective reaction coefficient, and the initial value is designed as 0.2;

[0013] Then, the influent residual chlorine content, the sludge concentration, the water temperature, the sludge contact reactor stirrer speed, the circulation flow rate, the influent flow rate, the sludge flow rate prediction value, and the effective volume of the reactor are input into the preset error back propagation neural network model, the effluent residual chlorine content is predicted, and an effluent residual chlorine content prediction value is output; when the difference between the effluent residual chlorine content prediction value and the effluent residual chlorine content control value is greater than 5% of the effluent residual chlorine content control value, the sludge flow rate prediction value is adjusted according to the ratio of the difference, the step rate is 0.1, the parameters re-determined are input into the preset neural network model, the effluent residual chlorine content is predicted, and the effluent residual chlorine content prediction value is output; until the difference between the effluent residual chlorine content prediction value and the effluent residual chlorine content control value is less than 5% of the effluent residual chlorine content control value, the current sludge flow rate prediction value is recorded, and the sludge flow rate prediction value is F s1 .

[0014] The method described above, characterized in that the actual effective reaction coefficient w2 is calculated according to the flow rate F s1 of the sludge added into the sludge contact reactor, and w2 is updated to replace w1 as the effective reaction coefficient for the next prediction:

[0015]

[0016] The method described above, characterized in that the sludge contact reactor is operated according to F s1 , the effluent residual chlorine content actual value in the running time is obtained and recorded, the error between the effluent residual chlorine content prediction value and the effluent residual chlorine content actual value under the condition is calculated, the error is returned to the error back propagation neural network model, and the model is updated.

[0017] The method described above, characterized in that the error back propagation neural network model comprises two hidden layers and one P-ReLU activation function; and the learning rate of the two hidden layers is adaptively adjusted using the Adam algorithm.

[0018] A high-salt organic wastewater treatment system using the above method, characterized in that the system comprises a biochemical treatment system, an electrolytic oxidation system, a sludge contact reactor, a sludge concentration tank, and a sludge filter press connected in sequence.

[0019] The system as described above, characterized in that the sludge contact reactor comprises a reactor body, the upper part of which is cylindrical and the lower part of which is conical; the side wall of the upper part of the reactor body is provided with a sludge inlet, and the side wall of the lower part is provided with an electrolytic water inlet; the bottom of the reactor body is provided with a sludge outlet, and the top is provided with a water outlet; the inside of the reactor body is provided with a screw stirrer, and the propelling direction is downward.

[0020] The system as described above, characterized in that the sludge enters the reactor body along the tangential direction of the cylinder wall through the sludge inlet, and the electrolytic oxidation system water enters the reactor body along the tangential direction of the cylinder wall through the electrolytic water inlet; the direction of the sludge entering the reactor body is the same as the direction of the electrolytic oxidation system water entering the reactor body, and the rotating direction of the sludge and the electrolytic oxidation system water in the reactor body is the same as the rotating direction of the screw stirrer.

[0021] The system as described above, characterized in that the sludge contact reactor water is mixed with the electrolytic oxidation system water and then re-enters the sludge contact reactor.

[0022] The beneficial effects of the present application are:

[0023] The high-salt organic wastewater treatment method and system of the present application reduce the residual oxidizing property of the electrolytic oxidation system water at a lower cost, while promoting the removal of intracellular water from the sludge and improving the dewatering efficiency of the sludge; the real-time regulation of sludge flow solves the problem of inaccurate reaction adjustment control of the sludge contact reactor, and enables fine control of sludge flow and operating costs. The residual chlorine content of the system water does not exceed the standard, and the water can be directly used for steel slag stewing or directly used in the subsequent membrane treatment process, thereby improving the service life of the membrane treatment equipment. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The process schematic diagram for the water produced by the method of the present application to be directly used for steel slag stewing.

[0025] Figure 2 The process schematic diagram for the water produced by the method of the present application to be directly used for membrane treatment equipment.

[0026] Figure 3 The control principle schematic diagram of the sludge flow of the sludge contact reactor.

[0027] Figure 4 The structure schematic diagram of the sludge contact reactor of the present application. DETAILED DESCRIPTION

[0028] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described below in connection with specific embodiments of the present application and corresponding drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0029] It should also be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices, components or structures referred to must have a particular orientation, be constructed or operated in a particular orientation, and cannot be understood as a limitation on the present application.

[0030] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0031] The technical solutions provided by the present application will be described in detail below in connection with the accompanying drawings. Figure 1

[0032] As shown in Figures 1-2 The high-salt organic wastewater treatment method of the present application comprises the following steps:

[0033] (1) The high-salt organic wastewater to be treated enters the biochemical treatment system;

[0034] (2) The water produced by the biochemical treatment system enters the electrolytic oxidation system;

[0035] (3) The water produced by the electrolytic oxidation system enters the sludge contact reactor, reacts with the sludge added to the sludge contact reactor, the sludge produced by the sludge contact reactor is sent to the sludge thickening tank, and the water produced by the sludge contact reactor is directly used for steel slag hot braising, or sent to the membrane filtration system and / or the adsorption resin system and / or the ion exchange resin system for subsequent treatment.

[0036] The sludge produced by the sludge contact reactor enters the sludge thickening tank and the sludge filter press to produce dry sludge, and the water produced by the sludge contact reactor enters the adjusting tank and can be directly used for steel slag hot braising. Alternatively, Figure 2 ​As shown, the effluent from the sludge contact reactor enters the membrane treatment equipment. The concentrate produced by the multi-stage nanofiltration is used for steel slag curing, and the desalinated water enters the multi-stage reverse osmosis concentration. The water produced by the reverse osmosis system enters the new production water tank in the plant area. After defluorination and resin hardening, the concentrate enters the bipolar membrane electrodialysis system to produce 7% dilute hydrochloric acid and sodium hydroxide.

[0037] The sludge used in step (3) is the sludge produced by the biological treatment system. Alternatively, it can be sludge obtained from the biological treatment of domestic sewage.

[0038] like Figure 3 As shown, to ensure the reaction efficiency of the chemical reaction in the sludge contact reactor, the flow rate F of the sludge added to the sludge contact reactor in step (3) is... s1 Determine using the following method:

[0039] First, set the sludge flow rate estimate:

[0040] Among them, F S Set the value for sludge flow rate prediction, F W C represents the influent flow rate. I C represents the residual chlorine content in the influent. O C is the control value for residual chlorine content in the effluent. S Here, a1 is the sludge concentration, a1 is the empirical value of the proportion of organic components in the sludge (default value is 0.25), and w1 is the effective reaction coefficient (initial value is designed to be 0.2).

[0041] Then, the parameters of influent residual chlorine content, sludge concentration, water temperature, sludge contact reactor agitator speed, circulation flow rate, influent flow rate, estimated sludge flow rate, and effective reactor volume are input into a preset error backpropagation neural network model to predict the effluent residual chlorine content and output the predicted effluent residual chlorine content. The predicted effluent residual chlorine content is compared with the controlled effluent residual chlorine content. When the difference between the predicted and controlled effluent residual chlorine content is greater than 5% of the controlled effluent residual chlorine content, the sludge flow rate is gradually adjusted by a step rate of 0.1 to approximate the difference. The newly determined parameters are then input into the preset neural network model to predict the effluent residual chlorine content and output the predicted effluent residual chlorine content. This process continues until the difference between the predicted and controlled effluent residual chlorine content is less than 5% of the controlled effluent residual chlorine content. At this point, the current estimated sludge flow rate is recorded as F. s1 .

[0042] The influent flow rate, circulating flow rate, and sludge flow rate of the sludge contact reactor are obtained through online flow meters. The sludge concentration is obtained through online or portable sludge concentration meters. The influent residual chlorine content and effluent residual chlorine content are obtained through high-range online residual chlorine detectors. The influent oxidation-reduction potential and effluent oxidation-reduction potential are obtained through online oxidation-reduction potential meters.

[0043] According to the flow F of the sludge added into the sludge contact reactor s1 , the actual effective reaction coefficient w2 is calculated, w2 is updated to replace w1 as the effective reaction coefficient for the next prediction:

[0044]

[0045] The sludge contact reactor is operated according to F s1 , the actual value of the residual chlorine content of the effluent is obtained and recorded within the operation time, the error between the predicted value of the residual chlorine content of the effluent and the actual value of the residual chlorine content of the effluent under the condition is calculated, the error is returned to the error back propagation neural network model, and the model is updated.

[0046] The error back propagation neural network model comprises two hidden layers and a P-ReLU activation function; the learning rate of the two hidden layers is adaptively adjusted using the Adam algorithm.

[0047] At the initial stage of the case implementation, the control parameter adjustment fluctuation is large, when the residual chlorine of the electrolytic effluent is about 500mg / L, the residual chlorine of the produced water is more than 100mg / L; after two months of case implementation, the residual chlorine of the produced water is stably lower than 40mg / L.

[0048] The high-salt organic wastewater treatment system of the application comprises a biochemical treatment system, an electrolytic oxidation system, a sludge contact reactor, a sludge thickening tank and a sludge filter press connected in sequence.

[0049] As shown in Figure 4 , the sludge contact reactor comprises a reactor body 3, the upper part of the reactor body 3 is cylindrical, and the lower part is conical table cylindrical. The side wall of the upper part of the reactor body 3 is provided with a sludge inlet 2, and the side wall of the lower part is provided with an electrolytic water inlet 1. The bottom of the reactor body 3 is provided with a sludge outlet 8, and the top is provided with a produced water outlet 7. The inside of the reactor body 3 is provided with a screw stirrer 4, and the propelling direction is downward.

[0050] The sludge enters the reactor body 3 along the tangential direction of the cylinder wall through the sludge inlet 2, and the electrolytic oxidation system effluent enters the reactor body 3 along the tangential direction of the cylinder wall through the electrolytic water inlet 1, the direction of the sludge entering the reactor body 3 is the same as that of the electrolytic oxidation system effluent entering the reactor body 3, and the rotating direction of the sludge and the electrolytic oxidation system effluent in the reactor body is the same as that of the screw stirrer 4.

[0051] The reactor has a water outlet guide cylinder 5 in the center of the upper part, which is a conical table cylinder, and the upper end side of the guide cylinder is connected with a horizontal water outlet pipe. The reactor top is provided with an exhaust pipe 6.

[0052] The tangential direction of the conical cylinder at the lowermost end of the reactor is the sludge outlet, and the direction of the sludge outlet is the same as the rotating direction of the screw stirrer. Two sludge outlets are arranged. After the sludge is discharged, it enters the subsequent sludge thickening tank and sludge filter press. The sewage enters along the tangential direction of the reactor cylinder, and under the action of its own high-speed jet and the screw stirrer, it rotates and diffuses, and under the action of gravity and the screw stirrer, it slowly rotates downward. In the reactor, there is a large velocity gradient between water with different cyclone radii and between water and sludge particles, which accelerates the reaction rate of residual chlorine and oxidizable components in sludge particles. The cells in the sludge particles are oxidized and degraded by high-concentration residual chlorine, the cell membrane is disintegrated, and the internal water of the cells is released, which improves the subsequent sludge dewatering effect.

[0053] The water produced by the sludge contact reactor is mixed with the water produced by the electrolytic oxidation system, and then reenters the sludge contact reactor through the circulating pump 9.

[0054] The above-mentioned embodiments are not limited to the above-mentioned examples, and other combinations of related devices are also within the scope of the present application. The above-mentioned embodiments are only for the purpose of illustrating the present application, and are not a limitation on the present application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and therefore all equivalent technical solutions should also belong to the scope of the present application.

Claims

1. A method for treating high-salinity organic wastewater, characterized in that, The method includes the following steps: (1) The high-salt organic wastewater to be treated enters the biochemical treatment system; (2) The wastewater produced by the biochemical treatment system enters the electrolytic oxidation system; (3) The water produced by the electrolytic oxidation system enters the sludge contact reactor and reacts with the sludge added to the sludge contact reactor. The sludge produced by the sludge contact reactor is sent to the sludge thickening tank. The water produced by the sludge contact reactor is directly used for hot slag quenching of steel slag, or sent to at least one of the membrane filtration system, adsorption resin system and ion exchange resin system for subsequent treatment. The flow rate F of the sludge added to the sludge contact reactor in step (3) s1 Determine using the following method: First, set the sludge flow rate prediction settings: ; Among them, F S Set the value for sludge flow rate prediction, F W C represents the influent flow rate. i C is the residual chlorine content in the influent, and C0 is the control value for the residual chlorine content in the effluent. S Here, a1 is the sludge concentration, a1 is the empirical value of the proportion of organic components in the sludge, with a value of 0.25, and w1 is the effective reaction coefficient, with an initial value of 0.

2. Then, the influent residual chlorine content, sludge concentration, water temperature, sludge contact reactor agitator speed, circulation flow rate, influent flow rate, sludge flow rate, and effective reactor volume are input into a preset error backpropagation neural network model to predict the effluent residual chlorine content and output the predicted effluent residual chlorine content. The predicted effluent residual chlorine content is compared with the controlled effluent residual chlorine content. When the difference between the predicted and controlled effluent residual chlorine content exceeds 5% of the controlled effluent residual chlorine content, the sludge flow rate is gradually adjusted by a step rate of 0.1 to approximate the difference. The newly determined parameters are then input into the preset error backpropagation neural network model to predict the effluent residual chlorine content and output the predicted effluent residual chlorine content. This process continues until the difference between the predicted and controlled effluent residual chlorine content is less than 5% of the controlled effluent residual chlorine content. At this point, the current sludge flow rate prediction setting is recorded as F. s1 .

2. The method for treating high-salinity organic wastewater as described in claim 1, characterized in that, The sludge used in step (3) is the sludge produced by the biochemical treatment system.

3. The method for treating high-salinity organic wastewater as described in claim 1, characterized in that, According to the flow rate F of the sludge added to the sludge contact reactor s1 Calculate the actual effective reaction coefficient w2, and replace w1 with w2 as the effective reaction coefficient for the next prediction: .

4. The method for treating high-salinity organic wastewater as described in claim 1, characterized in that, sludge contact reactor according to F s1 Run the system, acquire and record the actual value of residual chlorine content in the effluent during the running time, calculate the error between the predicted value and the actual value of residual chlorine content in the effluent, and return this error to the preset error backpropagation neural network model to update the preset error backpropagation neural network model.

5. The method for treating high-salinity organic wastewater as described in claim 1, characterized in that, The preset error backpropagation neural network model includes two hidden layers and a P-ReLU activation function; the learning rate of the two hidden layers is adaptively adjusted using the Adam algorithm.

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