Coal-containing wastewater treatment system and method

Abstract

The invention provides a coal-containing wastewater treatment system and a method thereof. The system comprises a rainwater collection tank, a coal water sedimentation tank, an electric flocculator, a centrifugal clarifier, a middle water tank, a self-cleaning filter, a fuel clean water tank, a clean water pump and a trestle ground flushing mechanism which are connected in sequence, the rainwater collection tank collects rainwater in a coal yard area and conveys the rainwater to the coal water sedimentation tank, and coal-containing wastewater of the coal yard directly enters the coal water sedimentation tank; the effluent of the coal water sedimentation tank is sequentially conveyed to an electric flocculator and a centrifugal clarifier for coagulation and clarification treatment, and the treated effluent enters a middle water tank; outlet water of the middle water tank is conveyed into a self-cleaning filter to be filtered, and filtered clear water is conveyed into a fuel clear water tank; the fuel clean water tank is conveyed to the trestle ground flushing mechanism through a clean water pump, and waste water obtained after flushing of the trestle ground flushing mechanism is conveyed to the coal water sedimentation tank, so that recycling of coal-containing waste water is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wastewater treatment, in particular to a coal-containing wastewater treatment system and method thereof. BACKGROUND

[0002] In the process of coal storage, transportation and processing, a large amount of coal-containing wastewater will be generated. If these coal-containing wastewater is directly discharged without effective treatment, not only the water resources will be wasted, but also the surrounding environment will be seriously polluted. The existing coal-containing wastewater treatment system has the problems of poor treatment effect and low water resource recycling rate, and cannot meet the increasingly strict industrial requirements. Therefore, it is of great practical significance to develop an efficient and environmentally friendly coal-containing wastewater treatment system. SUMMARY

[0003] The present application relates to the technical field of wastewater treatment, in particular to a coal-containing wastewater treatment system and method thereof.

[0004] In the first aspect of the present application, a coal-containing wastewater treatment system is provided, comprising: a rainwater collection pool, a coal water sedimentation pool, an electric flocculator, a centrifugal clarifier, an intermediate water tank, a self-cleaning filter, a fuel clean water pool, a clean water pump and a stack ground washing mechanism connected in sequence; the rainwater collection pool is used to collect rainwater in the coal yard area and transport it to the coal water sedimentation pool; the effluent of the coal water sedimentation pool is transported to the electric flocculator and the centrifugal clarifier in sequence for coagulation and clarification treatment, and the treated effluent enters the intermediate water tank; the effluent of the intermediate water tank is transported to the self-cleaning filter for filtration, and the filtered clean water is transported to the fuel clean water pool for storage; the fuel clean water pool is connected with the stack ground washing mechanism through the clean water pump; the clean water pump transports the clean water stored in the fuel clean water pool to the stack ground washing mechanism; the stack ground washing mechanism is used to wash the coal yard stack and transport the washed coal-containing wastewater to the coal water sedimentation pool.

[0005] Preferably, the coal-containing wastewater treatment system comprises: an ash yard water replenishing device; the ash yard water replenishing device is connected with the fuel clean water pool and is used to replenish water to the fuel clean water pool.

[0006] Preferably, a water level linkage control device is established between the ash yard water replenishing device and the fuel clean water pool; when the water level of the fuel clean water pool is lower than a preset safety threshold, the ash yard water replenishing device automatically starts the water replenishing process; when the water level of the fuel clean water pool returns to the normal range, the ash yard water replenishing device automatically stops water replenishing.

[0007] Preferably, the coal-containing wastewater treatment system comprises: a coal yard spraying water mechanism; the coal water sedimentation pool is connected with the coal yard spraying water mechanism; the coal-containing wastewater generated by the coal yard spraying water mechanism is transported to the coal water sedimentation pool.

[0008] Preferably, the rainwater collecting tank comprises: a primary rainwater collecting tank; the primary rainwater collecting tank is connected with a cyclone separator, a micro-filter screen and a coal water sedimentation tank in sequence through a rainwater conveying pump; the cyclone separator separates large coal cinder with a particle size greater than 5mm by centrifugal force; the micro-filter screen is used for intercepting 0.1-5mm suspended matters.

[0009] Preferably, the rainwater collecting tank comprises: a late-stage rainwater collecting tank; the late-stage rainwater collecting tank is connected with a rainwater filtering device, and the rainwater filtered through the rainwater filtering device is conveyed to a trestle ground washing mechanism.

[0010] Preferably, the coal water sedimentation tank is connected with the electric flocculator through a coal-containing wastewater lifting pump; and sludge generated by the coal water sedimentation tank is conveyed to a sludge drying bed.

[0011] Preferably, the intermediate water tank is connected with the self-cleaning filter through a filter water pump.

[0012] Preferably, the backwashing end of the self-cleaning filter is connected with the coal water sedimentation tank.

[0013] In the second aspect, the application provides a method of the coal-containing wastewater treatment system, comprising the following steps: the rainwater collecting tank collects rainwater in a coal yard area and conveys the rainwater to a coal water sedimentation tank, and coal-containing wastewater in the coal yard directly enters the coal water sedimentation tank; the effluent of the coal water sedimentation tank is conveyed to an electric flocculator and a centrifugal clarifier in sequence for coagulation and clarification treatment, and the treated effluent enters an intermediate water tank; the effluent of the intermediate water tank is conveyed to a self-cleaning filter for filtration, and the filtered clean water is conveyed to a fuel clean water tank; the fuel clean water tank conveys the clean water to a trestle ground washing mechanism through a clean water pump, and the wastewater after washing of the trestle ground washing mechanism is conveyed to the coal water sedimentation tank, so as to realize the recycling use of the coal-containing wastewater.

[0014] The application has at least the following beneficial effects: The coal-containing wastewater treatment system of the application can effectively remove coal cinder, suspended matters and other impurities in the coal-containing wastewater through the rainwater collecting tank, the coal water sedimentation tank, the electric flocculator, the centrifugal clarifier and the self-cleaning filter, and improve the wastewater treatment effect. The treated clean water is stored in the fuel clean water tank and can be used for purposes such as trestle ground washing, and the wastewater after washing is returned to the coal water sedimentation tank for further treatment, so that the water resource recycling is realized and the water resource waste is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or prior art description. Obviously, the drawings described below are only some embodiments of the present application, and all other drawings obtained by those of ordinary skill in the art without creative effort based on these drawings are within the scope of the present application.

[0016] Figure 1 Structure diagram of the coal-containing wastewater treatment system provided by the present application; Figure 2 System block diagram of the coal-containing wastewater treatment system provided by the present application Figure 1 ; Figure 3 System block diagram of the coal-containing wastewater treatment system provided by the present application Figure 2 .

[0017] Legend: 1 - rainwater collection tank; 2 - rainwater delivery pump; 3 - coal water sedimentation tank; 4 - coal-containing wastewater lifting pump; 5 - electric flocculator; 6 - sludge discharge pump; 7 - centrifugal clarifier; 8 - intermediate water tank; 9 - filter feed water pump; 10 - self-cleaning filter; 11 - fuel clean water tank; 12 - ash yard water replenishing device; 13 - clean water pump; 14 - stack ground washing mechanism; 15 - coal yard spraying water mechanism. DETAILED DESCRIPTION

[0018] The technical solutions of the present application will be described below in conjunction with the embodiments, obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of the present application.

[0019] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. 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 or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0021] Example 1 like Figures 1 to 3 As shown, this embodiment provides a coal-containing wastewater treatment system, including: a rainwater collection tank 1, a coal-water sedimentation tank 3, an electrocoagulant 5, a centrifugal clarifier 7, an intermediate water tank 8, a self-cleaning filter 10, a fuel water tank 11, a clean water pump 13, and a trestle ground washing mechanism 14 connected in sequence; the rainwater collection tank 1 is used to collect rainwater from the coal yard area and transport it to the coal-water sedimentation tank 3; the effluent from the coal-water sedimentation tank 3 is transported sequentially to the electrocoagulant 5 and the centrifugal clarifier 7 for coagulation and clarification treatment, and the treated effluent enters the intermediate water tank 8; the effluent from the intermediate water tank 8 is transported to the self-cleaning filter 10 for filtration, and the filtered clean water is transported to the fuel water tank 11 for storage, the fuel water tank 11 is connected to the trestle ground washing mechanism 14 through the clean water pump 13, the clean water pump 13 transports the clean water stored in the fuel water tank 11 to the trestle ground washing mechanism 14, the trestle ground washing mechanism 14 is used to wash the coal yard trestle, and transport the washed coal-containing wastewater to the coal-water sedimentation tank 3.

[0022] In this embodiment, the rainwater collection tank 1 includes: an initial rainwater collection tank; the initial rainwater collection tank is connected in sequence to a hydrocyclone separator, a microfiltration screen, and a coal-water sedimentation tank 3 via a rainwater delivery pump 2; the hydrocyclone separator uses centrifugal force to quickly separate large coal slag particles with a particle size greater than 5mm; the microfiltration screen is used to intercept suspended solids of 0.1-5mm.

[0023] The initial rainwater collection tank is constructed of reinforced concrete, with impermeable walls and bottom to prevent rainwater leakage. An openable cover facilitates inspection and cleaning. It is equipped with a rainwater transfer pump 2, made of corrosion-resistant alloy to withstand the characteristics of coal-containing wastewater. A screen is installed before the pump to intercept large debris. The initial rainwater collection tank collects initial rainwater from the coal yard area and transports it via the rainwater transfer pump 2 to a hydrocyclone separator and microfiltration screen for pretreatment, removing large coal slag particles and suspended solids.

[0024] In this embodiment, the rainwater collection tank 1 includes: a late rainwater collection tank; the late rainwater collection tank is connected with a rainwater filtering device, and rainwater filtered through the rainwater filtering device is delivered to the trestle ground washing mechanism 14. The late rainwater collection tank also adopts a reinforced concrete structure, but the volume design needs to be flexibly adjusted according to the subsequent water demand and rainfall conditions. A water level gauge is arranged in the tank to monitor the water level change in real time. The late rainwater collection tank is connected with the rainwater filtering device through a pipeline, and a valve is arranged on the pipeline to facilitate the control of water flow. The late rainwater collection tank collects subsequent rainwater, which is filtered through the rainwater filtering device and then directly delivered to the trestle ground washing mechanism 14 for use, thereby improving the water resource utilization rate.

[0025] In this embodiment, the coal-containing wastewater treatment system includes: an ash yard water supplementing device 12; the ash yard water supplementing device 12 is connected with the fuel clean water tank 11 and is used for supplementing water to the fuel clean water tank 11.

[0026] In this embodiment, a water level linkage control device is established between the ash yard water supplementing device 12 and the fuel clean water tank 11; when the water level of the fuel clean water tank 11 is lower than a preset safety threshold, the ash yard water supplementing device 12 automatically starts the water supplementing process; when the water level of the fuel clean water tank 11 returns to the normal range, the ash yard water supplementing device 12 automatically stops water supplementing.

[0027] Specifically, the water level linkage control device between the ash yard water supplementing device 12 and the fuel clean water tank 11 is constructed, and the ash yard water supplementing device 12 is automatically started and stopped according to the water level of the fuel clean water tank 11 through an intelligent control mode, so as to ensure that the water level of the fuel clean water tank 11 is stably in a safety range and the water supplementing quality meets the requirements. The float ball device of the ash yard water outlet automatically controls the opening and closing of the water outlet valve according to the water level of the ash yard, and the submersible pump pumps the water in the ash yard to the primary sedimentation tank. The water is subjected to sedimentation treatment in the primary sedimentation tank, and the sludge after sedimentation is periodically discharged through the sludge pump. The water after sedimentation is sequentially filtered through the primary quartz sand filter and the secondary activated carbon filter, and when the pressure difference between the inlet and outlet of the filter exceeds the set value, backwashing is performed. The treated water is delivered to the fuel clean water tank 11 through the water supplementing pipeline, and the electric valve on the water supplementing pipeline is opened and closed according to the instruction of the water level linkage control device. The water level sensor monitors the water levels of the fuel clean water tank 11 and the ash yard in real time, the water quality sensor monitors the water quality of the fuel clean water tank 11, and the data is transmitted to the water level linkage control device. The water level linkage control device automatically adjusts the operating state of the ash yard water supplementing device 12 according to the water level and water quality data and according to the preset control strategy, so as to ensure that the water level of the fuel clean water tank 11 is stably in a safety range and the water quality meets the requirements.

[0028] In this embodiment, multiple high-precision water level sensors are installed at different heights in the fuel water tank 11. Not only can the overall water level be detected, but also the uniformity of the water level in the tank can be determined by the data differences of the sensors at different positions, preventing false judgments of water level caused by local blockage or leakage. Water quality sensors are added to monitor the pH value, turbidity, and other indicators of the water in the fuel water tank 11 in real time. When the water quality changes due to long-term storage or other reasons, which may affect the subsequent use, an early warning signal is sent out, and the water replenishment strategy is adjusted, such as increasing the water replenishment frequency to dilute the poor water quality.

[0029] In this embodiment, the coal-containing wastewater treatment system includes a coal yard spraying water mechanism 15. The coal water sedimentation tank 3 is connected to the coal yard spraying water mechanism 15, and the coal-containing wastewater generated by the coal yard spraying water mechanism 15 is transported to the coal water sedimentation tank 3.

[0030] In this embodiment, the coal water sedimentation tank 3 is connected to the electric flocculator 5 through the coal-containing wastewater lifting pump 4. The sludge generated by the coal water sedimentation tank 3 is transported to the sludge drying bed.

[0031] In this embodiment, the coal water sedimentation tank 3 is connected to the electric flocculator 5 through the coal-containing wastewater lifting pump 4. In the selection of the coal-containing wastewater lifting pump 4, multiple factors need to be considered. First, according to the flow characteristics of the coal-containing wastewater in the coal water sedimentation tank 3, the flow parameters of the required lifting pump are accurately calculated. For example, by installing a flow monitoring device at the outlet of the sedimentation tank, the average flow over a period of time is continuously monitored, and combined with the overall design requirements of the wastewater treatment system, the rated flow of the lifting pump is determined to ensure that it can stably transport the wastewater in the sedimentation tank to the electric flocculator 5, and the flow meets the needs of the subsequent treatment process.

[0032] Second, the head requirement of the coal-containing wastewater is considered. Due to the possible vertical height difference between the sedimentation tank and the electric flocculator 5 and the pipe resistance, the required head of the lifting pump needs to be accurately calculated. By measuring and calculating the parameters such as pipe length, pipe diameter, and number of bends in detail, combined with empirical formulas, a reasonable head value is obtained, and a lifting pump that can provide sufficient head is selected to ensure that the wastewater can be smoothly transported to the electric flocculator 5.

[0033] The electric flocculator 5 is one of the key equipment in the coal-containing wastewater treatment system. Its working principle is to use the principle of electrolysis. Under the action of direct current, the metal anode (such as iron, aluminum, etc.) in the wastewater undergoes oxidation reaction to generate metal ions. These metal ions hydrolyze and polymerize in water to form a series of multi-core hydroxyl complexes and hydroxides. These substances have strong adsorption, coagulation, and precipitation properties, and can adsorb suspended solids, colloidal particles, and part of the dissolved pollutants in the wastewater, making them coagulate into larger flocs, which can be separated from the water.

[0034] The sludge conveying system can use screw pumps or centrifugal pumps as conveying equipment. Screw pumps have good performance in conveying sludge with large viscosity and many solid particles, and can ensure that the sludge is not easy to block the pipeline during conveying; centrifugal pumps have the advantages of large flow and high lift, and are suitable for long-distance and large-flow sludge conveying. According to the properties of the sludge and the conveying distance, select the appropriate conveying pump.

[0035] In terms of conveying pipelines, corrosion-resistant and wear-resistant materials such as stainless steel pipelines or rubber-lined steel pipelines should be selected. The pipe diameter of the pipeline should be selected according to the flow and flow rate of the sludge, and the flow rate can be controlled between 0.5-1.5 m / s. In order to reduce the sedimentation and blockage of the sludge in the pipeline, stirring devices can be installed in the pipeline or regular flushing can be performed.

[0036] The sludge drying bed is a simple and effective sludge treatment equipment, which is usually composed of a bed body, a drainage system, a ventilation system and the like. The bed body is generally made of concrete structure, a certain thickness of sand layer is laid at the bottom as a drainage layer, a filter material layer is laid above the sand layer, and the filter material layer can use quartz sand or anthracite coal, etc. The filter material layer is above the sludge spreading layer.

[0037] When the sludge generated by the coal water sedimentation tank 3 is conveyed to the sludge drying bed through the conveying system, the sludge is uniformly spread on the filter material layer. Under the action of gravity, the water in the sludge penetrates into the drainage system through the filter material layer and the sand layer, realizing the preliminary dewatering of the sludge. At the same time, the ventilation system introduces air into the drying bed, accelerating the evaporation of water in the sludge and further improving the drying effect of the sludge.

[0038] In this embodiment, the intermediate water tank 8 is connected with the self-cleaning filter 10 through the filter water pump 9.

[0039] In the process of treating coal-containing wastewater, the treatment capacity of the pre-treatment units (such as the rainwater collection tank 1, the coal water sedimentation tank 3, the electrocoagulator 5 and the centrifugal clarifier 7) may fluctuate due to factors such as water quality, equipment operation status and the like. For example, the water quantity of the rainwater collection tank 1 will suddenly increase during rainfall, and the treatment speed of the electrocoagulator 5 may also change when treating coal-containing wastewater with different concentrations. The intermediate water tank 8 can store a certain amount of water, play a buffering role, balance the water quantity difference between the pre-treatment and post-treatment units, and ensure the stable operation of the entire treatment system. When the water inflow of the upstream treatment unit is greater than the treatment capacity of the downstream treatment unit, the excess water can be temporarily stored in the intermediate water tank 8; when the downstream treatment unit needs more water, the intermediate water tank 8 can also supply water in time, avoiding the abnormal operation of the equipment or the poor treatment effect caused by uneven water quantity.

[0040] The water quality after the pre-treatment unit may still fluctuate. For example, the centrifugal clarifier 7 may cause the effluent turbidity to be unstable due to changes in the water quality of the influent when separating solid impurities. The intermediate water tank 8 can further mix and homogenize the treated water, making the water quality more stable. The water stays in the intermediate water tank 8 for a period of time, and the water entering the tank at different times mixes with each other, reducing the fluctuation range of water quality indicators (such as turbidity, coal content, etc.), providing more stable water quality conditions for the subsequent self-cleaning filter 10, and being beneficial to improve the filtering effect of the self-cleaning filter 10 and prolong its service life.

[0041] In order to enable the water in the intermediate water tank 8 to be fully mixed and homogenized, a stirring device or a flow guide plate can be arranged inside the water tank. The stirring device can adopt mechanical stirring or air stirring to make the water flow and mix, improving the uniformity of the water quality. The flow guide plate can change the flow direction of the water, prolong the residence time of the water in the water tank, and promote the stability of the water quality. In addition, a liquid level meter should be arranged inside the water tank to monitor the liquid level of the water tank in real time, providing a basis for the operation control of the system.

[0042] In this embodiment, the backwash end of the self-cleaning filter 10 is connected with the coal water sedimentation tank 3. In the coal-containing wastewater electroflocculation treatment process, the self-cleaning filter 10 plays a key role, which can effectively remove fine particles and impurities in the water, and ensure the normal operation of the subsequent water equipment. However, after the self-cleaning filter 10 operates for a period of time, a large amount of impurities will accumulate on the surface of the filter element, causing the filtration resistance to increase and the filtration effect to decrease, at which time backwashing operation is needed. Connecting the backwash end of the self-cleaning filter 10 with the coal water sedimentation tank 3 can realize the reasonable recycling of backwash water, saving water resources and avoiding environmental pollution caused by random discharge of backwash water.

[0043] A pipeline is led out from the clean water outlet of the self-cleaning filter 10 as a backwash water inlet pipeline, and a backwash water inlet valve is arranged on the pipeline. The backwash water inlet valve adopts an electric ball valve or a pneumatic ball valve, which has the characteristics of quick opening and closing and good sealing performance, and is convenient for automatic control. The pipe diameter of the backwash water inlet pipeline should be designed according to the flow and velocity requirements of the backwash water, and generally the same or similar pipe diameter as the filter water inlet pipeline can be selected to ensure that the backwash water has sufficient pressure and flow. The backwash water is led to the coal water sedimentation tank 3. A backwash water outlet valve is arranged on the backwash water outlet pipeline, which also adopts an electric ball valve or a pneumatic ball valve to facilitate linkage control with the backwash water inlet valve. The backwash water outlet pipeline should have a certain slope to ensure that the backwash water can be smoothly discharged into the coal water sedimentation tank 3, avoiding water accumulation in the pipeline. The material of the pipeline can be selected from steel pipe or glass steel pipe according to the actual situation.

[0044] Example 2 The embodiment also provides a method for treating coal-containing wastewater, comprising the following steps: rainwater is collected by a rainwater collection pool 1 and transported to a coal water sedimentation pool 3, and coal-containing wastewater in a coal yard is directly introduced into the coal water sedimentation pool 3; water discharged from the coal water sedimentation pool 3 is sequentially transported to an electroflocculator 5 and a centrifugal clarifier 7 for coagulation and clarification treatment, and the treated water is introduced into an intermediate water tank 8; water discharged from the intermediate water tank 8 is transported to a self-cleaning filter 10 for filtration, and the filtered clean water is transported to a fuel clean water pool 11; the fuel clean water pool 11 is transported to a trestle ground washing mechanism 14 through a clean water pump 13, and wastewater washed by the trestle ground washing mechanism 14 is transported to the coal water sedimentation pool 3, so that the coal-containing wastewater is recycled.

[0045] The method constructs a complete and interlocking coal-containing wastewater recycling treatment process system. First, rainwater collection facilities are arranged in the coal yard area, and the collected rainwater is transported to the rainwater collection pool 1, and at the same time, the coal-containing wastewater in the coal yard is directly introduced into the coal water sedimentation pool 3 after the large particle impurities are intercepted by the grid, and is combined with the rainwater in the coal water sedimentation pool 3 and is naturally deposited, and the short flow is avoided by the guide wall, and the sludge is regularly discharged to maintain the sedimentation effect; the water discharged from the sedimentation pool is transported to the electroflocculator 5 by the pump, and under the action of the electrochemical reaction generated by the electrode plate and the appropriate coagulant, the colloidal particles and soluble pollutants in the wastewater are coagulated into larger flocs; then, the water is introduced into the centrifugal clarifier 7, and the flocs and water are separated under the action of high-speed rotating centrifugal force, and the clean water overflows, and the sludge is regularly discharged to the coal water sedimentation pool 3 by the sludge pump 6; then, the clarified water flows into the intermediate water tank 8, and is then pumped to the self-cleaning filter 10, and small particle impurities are intercepted by the filter, and when the pressure difference between the inlet and outlet reaches the set value, automatic backwashing is performed, and the backwashing water is discharged back to the coal water sedimentation pool 3; the filtered clean water is stored in the fuel clean water pool 11, and is transported to the trestle ground washing mechanism 14 by the clean water pump 13 to wash the trestle ground, and the wastewater washed is returned to the coal water sedimentation pool 3, so that a closed cycle is formed, and the coal-containing wastewater is effectively treated and recycled.

[0046] The specific method flow of the embodiment is as follows: S1, rainwater collection and wastewater combination stage; Rainwater collection: rainwater collection facilities such as rainwater ditches and water collection wells are reasonably planned and arranged in the coal yard area. The smoothness of the rainwater collection facilities is regularly checked, and the debris and sludge in the ditch are cleaned in time to ensure that the rainwater can flow smoothly into the rainwater collection pool 1. According to the local rainfall and the volume of the rainwater collection pool 1, the collection and discharge of rainwater are reasonably arranged to avoid overflow or low water level of the rainwater collection pool 1.

[0047] Wastewater collection: coal-containing wastewater from the coal yard is directly discharged into the coal-water sedimentation tank 3 through a dedicated drainage pipeline. A grid is installed at the wastewater discharge port, and the gap between the grid bars is selected according to the size of the impurities in the wastewater, typically 10-20 mm. Regularly clean the large-particle impurities intercepted by the grid to prevent pipe blockage or affect the subsequent treatment effect.

[0048] S2, coal-water sedimentation tank 3 treatment stage; Sedimentation treatment: After the rainwater and coal-containing wastewater enter the coal-water sedimentation tank 3, they undergo natural sedimentation in the tank. A flow guide wall is installed in the sedimentation tank to ensure uniform water distribution and prevent short-circuiting. The hydraulic retention time of the sedimentation tank is controlled according to the water quality and quantity of the wastewater, typically 2-4 hours.

[0049] Sludge discharge operation: Regularly discharge sludge from the sedimentation tank, which can be done using a sludge pump or gravity discharge. The sludge discharge frequency is determined based on the amount of sludge produced and the actual situation of the sedimentation tank, and it is generally recommended to discharge sludge 1-2 times a day. When discharging sludge, pay attention to controlling the amount of sludge to avoid reducing the effective volume of the sedimentation tank or causing sludge accumulation due to insufficient sludge discharge.

[0050] S3, electrocoagulation device 5 treatment stage; Device start-up and operation: The effluent from the coal-water sedimentation tank 3 is pumped to the electrocoagulation device 5. Before starting the electrocoagulation device 5, check the connection of the electrode plates and the normality of other parts of the device. Adjust the current density of the electrocoagulation device 5 according to the water quality of the wastewater, typically 10-50 A / m². At the same time, add an appropriate amount of coagulant aid, such as polyacrylamide (PAM), to the electrocoagulation device 5 through a metering pump, and the dosage is generally controlled at 1-5 mg / L.

[0051] Process monitoring and adjustment: During the operation of the electrocoagulation device 5, regularly monitor the treatment effect of the wastewater, such as observing the formation and size of the flocs. Based on the monitoring results, adjust the current density and coagulant aid dosage in a timely manner to achieve the best coagulation effect.

[0052] S4, centrifugal clarifier 7 treatment stage; Inlet water and separation: The effluent from the electrocoagulation device 5 enters the centrifugal clarifier 7. Adjust the rotational speed of the centrifugal clarifier 7 according to the treatment capacity of the wastewater and the separation effect requirements, typically 1000-3000 r / min. Under the action of the centrifugal force generated by high-speed rotation, the flocs are separated from the water, and the flocs are deposited at the bottom of the clarifier, while the clear water overflows from the top.

[0053] Sludge discharge: periodically discharge the sludge at the bottom of the centrifugal clarifier 7, which can be discharged in a batch or continuous manner. When discharging the sludge, pay attention to control the discharge speed and flow to avoid affecting the normal operation of the clarifier. At the same time, check the sludge discharge to ensure that the sludge can be smoothly discharged.

[0054] S5, self-cleaning filter 10 processing stage; Filtering operation: the water treated by the centrifugal clarifier 7 enters the intermediate water tank 8, and then is transported to the self-cleaning filter 10 through a pump. The self-cleaning filter 10 automatically filters the water to intercept the residual small particles and impurities in the water. According to the subsequent water requirements, select the appropriate filtering accuracy, which can generally be selected as 50-100 μm.

[0055] Backwashing operation: when the pressure difference between the inlet and outlet of the self-cleaning filter 10 reaches the set value, which is generally set as 0.05-0.1 MPa, the backwashing program is automatically triggered. The backwashing water is part of the filtered water, which is used to reverse flush the filter element through the backwashing device to flush the impurities on the surface of the filter element and discharge to the coal water sedimentation tank 3. The backwashing period can also be set according to the running time, which is generally set as 8-12 hours for backwashing once.

[0056] S6, clean water storage and trestle ground washing stage; Clean water storage: the clean water filtered by the self-cleaning filter 10 is transported to the fuel clean water tank 11 for storage. The fuel clean water tank 11 is provided with a liquid level control device, which stops water inflow when the water level reaches a certain height, and timely supplements clean water when the water level is too low. Periodically check the water quality of the fuel clean water tank 11 to ensure that the water quality meets the requirements.

[0057] Trestle ground washing: the clean water in the fuel clean water tank 11 is transported to the trestle ground washing mechanism 14 through the clean water pump 13 to wash the trestle ground. According to the use condition and pollution degree of the trestle, reasonably adjust the washing frequency and time, which is generally recommended to be washed 1-2 times a day, and each washing time is 10-20 minutes. The waste water after washing is transported to the coal water sedimentation tank 3 through the drainage pipeline for further treatment to realize the recycling of the coal-containing waste water.

[0058] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A coal-containing wastewater treatment system, characterized in that, include: The system comprises, in sequence, a rainwater collection tank, a coal-water sedimentation tank, an electrocoagulator, a centrifugal clarifier, an intermediate water tank, a self-cleaning filter, a fuel water tank, a clean water pump, and a trestle ground washing mechanism. The rainwater collection tank collects rainwater from the coal yard area and transports it to the coal-water sedimentation tank. The effluent from the coal-water sedimentation tank is sequentially transported to the electrocoagulator and centrifugal clarifier for coagulation and clarification treatment, and the treated effluent enters the intermediate water tank. The effluent from the intermediate water tank is transported to the self-cleaning filter for filtration, and the filtered clean water is stored in the fuel water tank. The fuel water tank is connected to the trestle ground washing mechanism via a clean water pump, which transports the stored clean water from the fuel water tank to the trestle ground washing mechanism. The trestle ground washing mechanism is used to wash the coal yard trestle and transports the washed coal-containing wastewater to the coal-water sedimentation tank.

2. The coal-containing wastewater treatment system according to claim 1, characterized in that, include: Ash field water replenishment device; The ash field water replenishment device is connected to the fuel water tank and is used to replenish the fuel water tank.

3. The coal-containing wastewater treatment system according to claim 2, characterized in that, A water level linkage control device is established between the ash field water replenishment device and the fuel water tank; when the water level in the fuel water tank is lower than the preset safety threshold, the ash field water replenishment device automatically starts the water replenishment process; when the water level in the fuel water tank returns to the normal range, the ash field water replenishment device automatically stops water replenishment.

4. The coal-containing wastewater treatment system according to claim 1, characterized in that, include: A coal yard spraying water system is provided, wherein the coal water sedimentation tank is connected to the coal yard spraying water system, and the coal-containing wastewater generated by the coal yard spraying water system is transported to the coal water sedimentation tank.

5. The coal-containing wastewater treatment system according to claim 4, characterized in that, The rainwater collection tank includes: an initial rainwater collection tank; the initial rainwater collection tank is connected in sequence to a hydrocyclone separator, a microfiltration screen, and a coal-water sedimentation tank via a rainwater delivery pump; the hydrocyclone separator uses centrifugal force to quickly separate large coal slag particles with a diameter greater than 5mm; the microfiltration screen is used to intercept suspended solids of 0.1-5mm.

6. The coal-containing wastewater treatment system according to claim 5, characterized in that, The rainwater collection pool includes a secondary rainwater collection pool; the secondary rainwater collection pool is connected to a rainwater filtration device, and the rainwater filtered by the rainwater filtration device is transported to the trestle ground washing mechanism.

7. The coal-containing wastewater treatment system according to claim 1, characterized in that, The coal-water sedimentation tank is connected to the electrocoagulant via a coal-containing wastewater booster pump; the sludge produced by the coal-water sedimentation tank is transported to the sludge drying bed.

8. The coal-containing wastewater treatment system according to claim 1, characterized in that, The intermediate water tank is connected to the self-cleaning filter via a filter water supply pump.

9. The coal-containing wastewater treatment system according to claim 1, characterized in that, The backwash end of the self-cleaning filter is connected to the coal-water sedimentation tank.

10. A method for treating coal-containing wastewater according to any one of claims 1 to 9, characterized in that, The process includes the following steps: a rainwater collection pond collects rainwater from the coal yard area and transports it to a coal-water sedimentation pond; coal-containing wastewater from the coal yard directly enters the coal-water sedimentation pond; the effluent from the coal-water sedimentation pond is sequentially transported to an electrocoagulator and a centrifugal clarifier for coagulation and clarification treatment, and the treated effluent enters an intermediate water tank; the effluent from the intermediate water tank is transported to a self-cleaning filter for filtration, and the filtered clean water is transported to a fuel water tank; the fuel water tank is pumped to a trestle ground washing mechanism, and the wastewater from the trestle ground washing mechanism is transported to the coal-water sedimentation pond to achieve the recycling of coal-containing wastewater.

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