System and method for retarding sludge calcification of anaerobic reactor

Abstract

The invention discloses a system and a method for slowing down sludge calcification of an anaerobic reactor, a pretreatment device is respectively connected with a sludge adsorption device, a leachate tank and a pressure filtrate tank, the leachate tank is connected with a sludge treatment device, and leachate generated by the sludge treatment device enters the leachate tank; the sludge adsorption device is connected with the pressure filtrate tank; the pressure filtrate tank is connected with the anaerobic treatment device; sludge press filtrate and leachate in the leachate pool are put into the pretreatment device according to a preset proportion, carbonate ions in the sludge press filtrate neutralize calcium ions in the leachate and form chemical sludge, products of the pretreatment device are conveyed to the sludge adsorption device to be filtered and separated, generated filtrate enters the press filtrate pool, and the filtrate enters the leachate pool. Filtrate in the pressure filtrate tank is fed into the anaerobic treatment device or returns to the pretreatment device. The device has the characteristics of compact structure, convenience in operation, high reliability and the like, the alkalinity in the sludge pressure filtrate is fully utilized, the overall investment and operation cost is low, and the engineering implementation difficulty is low.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sludge treatment, in particular to a system and method for slowing down sludge calcification in an anaerobic reactor. BACKGROUND

[0002] Anaerobic reactors such as UASB (upflow anaerobic sludge bed), IC (internal circulation anaerobic reactor), EGSB (expanded granular sludge bed) have been widely used in various types of high-concentration organic wastewater due to their high operating load, good treatment effect, small land occupation, good sludge-water separation, and strong resistance to load shock, etc. due to the use of anaerobic granular sludge. The leachate from municipal solid waste incineration contains a high concentration of calcium ions (2000-3500 mg / L). High-concentration calcium ions and carbonate produced by the degradation of organic matter in the anaerobic reactor form CaCO3 precipitates within a certain temperature and pH range, and adhere to the granular sludge, increasing the inorganic content of the granular sludge and reducing its activity, exhibiting the characteristics of granular sludge calcification.

[0003] Granular sludge calcification can cause the following hazards: ① CaCO3 precipitates can promote the adhesion and aggregation of granular sludge, causing channeling and blockage, reducing mass transfer efficiency, reducing microbial abundance, and ultimately reducing the activity of granular sludge or even inactivating it; ② The replacement cost of granular sludge is high and difficult to handle; in addition, the restart of the anaerobic reactor requires a long time (2-3 months), which may cause the entire system to malfunction; ③ The increase in the amount of residual sludge increases the treatment cost of high-calcium wastewater; ④ CaCO3 precipitates cause an increase in the ash content of the sludge, and the active components in the sludge are gradually eliminated, with inorganic components occupying a large amount of space in the reactor, reducing the treatment efficiency of the reactor, and even causing it to fail; ⑤ High-concentration calcium ions in wastewater can also cause scaling and blockage of equipment pipes, damaging the equipment, increasing the replacement cost and handling difficulty; ⑥ Granular sludge calcification will greatly increase the difficulty of anaerobic sludge discharge, and cause severe wear and tear on the sludge discharge pump.

[0004] Chinese patent application 201810603235.8 discloses an IC anaerobic reactor device and method for slowing down sludge calcification. The technical solution uses the method of gas extraction at the upper end of the anaerobic reactor and gas lifting at the lower end to accelerate the production of biogas in the reaction chamber into the lifting pipe, reduce the carbon dioxide concentration on the surface of the sludge in the reaction chamber, and thus reduce the generation of calcium salt precipitates and alleviate the inactivation of granular sludge. This method causes a significant decrease in the methane concentration in the biogas produced in the anaerobic reactor, reducing the utilization rate of biogas, and also posing a safety hazard of methane gas explosion.

[0005] Chinese patent application 202122942618.8 discloses a device for preventing calcification in papermaking wastewater anaerobic treatment. The technical solution consumes the alkalinity in the treated wastewater through an acidification tank and a nitrogen-phosphorus solution, reducing the degree of granular sludge calcification. This method consumes a large amount of material, and the calcium ions in the treated wastewater are not effectively treated, posing a great risk to the stable operation of subsequent sections.

[0006] Chinese patent application 201910821384.6 discloses a calcification control method and system for high-calcium organic wastewater anaerobic treatment. The scheme achieves enhanced buffering capacity of the influent pH through pretreatment at the front end, provides essential nutrients for microbial growth, and prevents the formation of scale from calcium ions and anions such as carbonate and phosphate. A continuously operating sludge circulation and separation system is built to enhance the circulation contact between sludge and wastewater and the separation of calcium sludge, addressing the calcification problem in high-calcium, high-concentration organic wastewater anaerobic treatment from the perspectives of continuous prevention and separation. The technology uses phosphoric acid, sodium dihydrogen phosphate, disodium hydrogen phosphate, and / or hydrochloric acid to adjust the pH value to be acidic. The shortcomings of this scheme include: (1) a large amount of material is consumed to adjust the pH value; (2) the calcium ions in the treated wastewater are not effectively treated, posing a great risk to the stable operation of subsequent sections; (3) the pretreated wastewater is strongly acidic, and the optimal pH value for the anaerobic reactor is controlled at 7.3-7.8 (slightly alkaline). The strong acid wastewater entering the anaerobic reactor has a great impact on the stable operation of the anaerobic reactor, making it difficult to ensure the organic removal effect of the anaerobic reactor.

[0007] Chinese patent application 201811442843.1 discloses a method and system for synergistically treating landfill leachate and sludge press filtrate. The technical solution mixes landfill leachate and sludge press filtrate in a certain ratio and sequentially passes through anaerobic, biochemical, and membrane treatment devices to achieve synergistic treatment of landfill leachate and sludge press filtrate. This scheme solves the problem of synergistic treatment of landfill leachate and sludge press filtrate, but does not solve the problem of sludge calcification in the anaerobic reactor. Moreover, the mixing of landfill leachate and sludge press filtrate in the conditioning tank will generate a certain amount of chemical sludge, which will deposit at the bottom of the conditioning tank, accelerating the blockage of the conditioning tank effluent pipeline and pump body. SUMMARY

[0008] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art and provide a system and method for slowing down sludge calcification in an anaerobic reactor, which is compact in structure, easy to operate, and high in stability.

[0009] To solve the above technical problems, the technical scheme adopted by the present application is as follows: The system for slowing down sludge calcification in an anaerobic reactor comprises a pretreatment device, a sludge adsorption device, a sludge treatment device, a sewage receiving device and an anaerobic treatment device; the sewage receiving device comprises a leachate tank and a pressure leachate tank, the pretreatment device is connected with the sludge adsorption device, the leachate tank and the pressure leachate tank respectively, the leachate tank is connected with the sludge treatment device, and the leachate generated by the sludge treatment device enters the leachate tank; the sludge adsorption device is connected with the pressure leachate tank, and the pressure leachate tank is connected with the anaerobic treatment device; sludge pressure leachate and leachate in the leachate tank are put into the pretreatment device according to a preset ratio, so that bicarbonate ions in the sludge pressure leachate neutralize calcium ions in the leachate and form chemical sludge, the chemical sludge in the pretreatment device is transported to the sludge adsorption device to realize filtration and separation, the filtrate generated by the sludge adsorption device enters the pressure leachate tank, and the filtrate in the pressure leachate tank is sent to the anaerobic treatment device or returned to the pretreatment device.

[0010] As a further improvement of the present application, the pretreatment device comprises a reactor, a stirrer is arranged in the reactor, a sludge pressure leachate conveying pipeline is arranged at the upper portion of the reactor, and a pressure leachate flow meter is arranged on the conveying pipeline; a leachate lifting pump, a No. 3 filter and a leachate flow meter are arranged on the connecting pipeline between the leachate tank and the reactor.

[0011] As a further improvement of the present application, the pretreatment device further comprises an internal circulation pump, the internal circulation pump is connected with the reactor through a circulation pipeline, and a multifunctional detector and an internal circulation flow meter are arranged on the circulation pipeline.

[0012] As a further improvement of the present application, the pretreatment device further comprises a buffer solution preparation tank, the buffer solution preparation tank is connected with the reactor through a pipeline provided with a buffer solution feeding pump, so as to convey alkaline buffer solution into the reactor to control the pH value in the reactor to be between 10.5 and 11.5.

[0013] As a further improvement of the present application, the sludge adsorption device comprises a filter tank, the reactor conveys chemical sludge into the filter tank through a pipeline provided with a spraying pump, a control valve and a spray head, a filter bed is arranged in the filter tank to realize filtration of the chemical sludge, and the filter tank is connected with the pressure leachate tank through a pipeline provided with a flow meter, a suspended substance detector and a filter to convey filtrate into the pressure leachate tank.

[0014] As a further improvement of the present application, the spray head is a plurality of spray heads, which are arranged above the filter bed; the filter bed is filled with domestic waste, and the filling height is 1-2 meters, so as to filter the chemical sludge generated by the pretreatment device.

[0015] As a further improvement of the present application, the sludge treatment device comprises a garbage storage pit and a garbage crane, the garbage storage pit is connected to the leachate pool through a pipeline; the anaerobic treatment device comprises an anaerobic water inlet pump, a third suspended solids detector and an anaerobic reactor, and a connecting pipeline with the anaerobic water inlet pump and the third suspended solids detector is arranged between the anaerobic reactor and the pressure leachate pool.

[0016] As a general technical concept, the present application also provides a method for slowing down sludge calcification in an anaerobic reactor, which is implemented based on the above-mentioned system for slowing down sludge calcification in an anaerobic reactor, and comprises the following steps: Step S1, continuously and uniformly conveying the leachate and the sludge pressure leachate to the reactor at a ratio of 4-6:1, starting the stirrer and the internal circulation pump to accelerate the pretreatment reaction, neutralizing the calcium ions in the leachate with the bicarbonate ions in the sludge pressure leachate to form chemical sludge, controlling the pH during the reaction to be 10.5-11.5, controlling the temperature to be 27-39℃, and controlling the sludge concentration to be 5-12g / L; Step S2, conveying the chemical sludge generated in the reactor to the filter pool through the spray pump and the spray head, realizing sludge-water separation through the filter bed filled with garbage, conveying the obtained filtrate into the pressure leachate pool, conveying the filter residue to the garbage storage pit through the grab bucket, mixing the filter residue with the garbage in the garbage storage pit, and then conveying the mixture to the household garbage incinerator for joint treatment through the garbage crane; Step S3, collecting and conveying the leachate and the calcium removal wastewater: the leachate produced by the garbage storage pit enters the leachate pool, and then is conveyed to the reactor through the leachate lifting pump; the conveying flow rate of the leachate is interlocked with the conveying flow rate of the sludge pressure leachate; Step S4, when the calcium ion concentration of the filtrate in the pressure leachate pool is lower than 500mg / L, the filtrate is lifted to the anaerobic reactor through the anaerobic water inlet pump for joint treatment; if the calcium ion concentration of the filtrate in the pressure leachate pool exceeds 500mg / L, the emergency reprocessing pump is started to convey the filtrate to the reactor for secondary hardness removal treatment.

[0017] As a further improvement of the present application, in step S1, the stirrer is started in the order of fast stirring and slow stirring, the fast stirring speed is 200-400rpm, the fast stirring time is 3-4h, the slow stirring speed is 50-100rpm, the slow stirring time is 1-2h, and the hydraulic retention time is 4-6h.

[0018] As a further improvement of the present application, in step S2, the spray area of the filter bed is divided into n zones, and the radiation radius of a single spray zone is 0.5-1m; when the pressure difference before and after the filter reaches 0.8-1.3bar or the water phase liquid level height of the filter pool exceeds 0.5m, the filter bed or the spray area needs to be replaced.

[0019] Compared with the prior art, the present application has the following advantages: The present application makes full use of the water quality characteristics of high alkalinity (8000-15000 mg / L) of sludge filter press liquor, carries out calcium removal and softening pretreatment on high calcium leachate, separates sludge and water by using the filter characteristics of domestic waste bed on the calcium removal wastewater, reduces the calcium ion concentration in leachate wastewater, effectively slows down the sludge calcification problem of the rear-end anaerobic reactor. At the same time, the co-treatment of domestic waste incineration leachate and sludge filter press liquor is realized, and the organic matter in two different wastewaters is effectively degraded. The present application makes full use of the alkalinity in the sludge filter press liquor, has low overall investment cost, low engineering implementation difficulty and low operation cost. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The structure principle schematic diagram of the system for slowing down sludge calcification of anaerobic reactor in the embodiment of the present application is shown. Figure 2 The flow process schematic diagram of the system for slowing down sludge calcification of anaerobic reactor in the embodiment of the present application is shown. Legend: 1, pretreatment device; 11, reactor; 12, filter press liquor flow meter; 131, buffer solution preparation tank; 132, buffer solution dosing pump; 141, internal circulation pump; 142, multifunctional detector; 143, internal circulation flow meter; 15, stirrer; 2, sludge adsorption device; 21, spraying pump; 22, No. 1 sludge filter tank; 23, No. 2 sludge filter tank; 24, flow meter; 221, No. 1 water inlet valve; 222, No. 1 suspended solids detector; 223, No. 1 spraying head; 224, No. 1 filter bed; 225, No. 1 liquid level meter; 226, No. 1 filter; 231, No. 2 water inlet valve; 232, No. 2 suspended solids detector; 233, No. 2 spraying head; 234, No. 2 filter bed; 235, No. 2 liquid level meter; 236, No. 2 filter; 3, sludge treatment device; 31, garbage storage pit; 32, garbage crane; 4, sewage receiving device; 41, leachate tank; 42, filter press liquor tank; 411, leachate lifting pump; 412, No. 3 filter; 413, leachate flow meter; 421, emergency reprocessing pump; 5, anaerobic treatment device; 51, anaerobic water inlet pump; 52, No. 3 suspended solids detector; 53, anaerobic reactor. DETAILED DESCRIPTION

[0021] The present application is further described below in combination with the drawings of the specification and specific preferred embodiments, but the protection scope of the present application is not limited thereby.

[0022] In the description of the present application, it should be understood that the terms "side", "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" 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 or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0023] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated, so that the features with "first", "second" can explicitly or implicitly include one or more of the features, and in the description of the present application, the meaning of "multiple" is two or more, unless otherwise explicitly and specifically limited.

[0024] Embodiments As Figure 1 shown, the system for slowing down the anaerobic reactor sludge calcification of the present application comprises a pretreatment device 1, a sludge adsorption device 2, a sludge treatment device 3, a sewage receiving device 4 and an anaerobic treatment device 5. The sewage receiving device 4 comprises a leachate tank 41 and a pressurized filtrate tank 42. The leachate tank 41 is composed of a leachate lifting pump 411, a No. 3 filter 412 and a leachate flow meter 413, and is used to receive the leachate produced in the sludge treatment device 3. The leachate lifting pump 411 is used for the leachate inlet of the pretreatment device 1, the No. 3 filter 412 is used to filter part of the chemical sludge carried by the sewage, and the leachate flow meter 413 is used to measure and control the leachate flow of the pretreatment device 1.

[0025] The pressurized filtrate tank 42 is provided with an emergency reprocessing pump 42, and the pressurized filtrate tank 42 is used to receive the calcium-removed sewage filtrate filtered by the sludge adsorption device 2, and the emergency reprocessing pump 421 is used to deliver the calcium-removed sewage to the pretreatment device 1 for secondary hardness removal.

[0026] The pretreatment device 1 is connected with the sludge adsorption device 2, the leachate tank 41 and the pressure filtrate tank 42 respectively, the leachate tank 41 is connected with the sludge treatment device 3, and the leachate generated by the sludge treatment device 3 enters the leachate tank 41. The sludge adsorption device 2 is connected with the pressure filtrate tank 42, and the pressure filtrate tank 42 is connected with the anaerobic treatment device 5. The sludge pressure filtrate and the leachate in the leachate tank 41 are put into the pretreatment device 1 according to a preset ratio, so that the bicarbonate ions in the sludge pressure filtrate neutralize the calcium ions in the leachate and form chemical sludge, the chemical sludge of the pretreatment device 1 is transported to the sludge adsorption device 2 to realize filtration separation. The filtrate generated by the sludge adsorption device 2 enters the pressure filtrate tank 42, and the filtrate in the pressure filtrate tank 42 is sent to the anaerobic treatment device 5 or returned to the pretreatment device 1. In the embodiment, before the landfill leachate enters the anaerobic reactor 53, the sludge pressure filtrate is reacted with the leachate to reduce the concentration of calcium ions in the leachate, slow down the long-term sludge calcification problem of the anaerobic reactor 53, improve the treatment efficiency of the anaerobic reactor 53 and prolong the dredging cycle of the anaerobic reactor 53.

[0027] In the embodiment, the sludge treatment device 3 includes a garbage storage pit 31 and a garbage crane 32. The garbage storage pit 31 is connected to the leachate tank 41 through a pipeline. The garbage storage pit 31 is used for storing household garbage, turning over the household garbage and separating leachate, and the garbage crane 32 is used for receiving and transferring the household garbage.

[0028] The anaerobic treatment device 5 includes an anaerobic water inlet pump 51, a third suspended matter detector 52 and an anaerobic reactor 53, and a connecting pipeline with the anaerobic water inlet pump 51 and the third suspended matter detector 52 is arranged between the anaerobic reactor 53 and the pressure filtrate tank 42. The anaerobic water inlet pump 51 is used to lift the calcium-removed wastewater collected in the pressure filtrate tank 42 to the rear-end anaerobic reactor 53, the suspended matter detector 52 is used to monitor the sludge concentration of the calcium-removed wastewater, and the anaerobic reactor 53 is one of UASB, IC and EGSB. As shown in Figure 1 The pretreatment device 1 includes a reactor 11, the reactor 11 is a reinforced concrete structure or a tank structure, and provides a chemical reaction place for the sludge pressure filtrate, the leachate and the buffer solution. A stirrer 15 is arranged in the reactor 11 to realize uniform stirring of materials. A conveying pipeline for conveying the sludge pressure filtrate is arranged at the upper portion of the reactor 11, and a pressure filtrate flow meter 12 is arranged on the conveying pipeline, which is used to measure and control the flow of the sludge pressure filtrate. A leachate lifting pump 411, a third filter 412 and a leachate flow meter 413 are arranged on the connecting pipeline between the leachate tank 41 and the reactor 11.

[0029] In this embodiment, the pretreatment device 1 further includes an internal circulation pump 141, which is connected to the reactor 11 via a circulation pipe. The circulation pipe is equipped with a multi-functional detector 142 and an internal circulation flow meter 143. The internal circulation pump 141 plays a role in uniform mixing and controlling the water flow rate in the reactor 11. The internal circulation flow meter 143 is used to measure the internal circulation flow rate and control the upward flow velocity in the reactor. The multi-functional detector 142 is used to measure parameters such as pH, temperature, and sludge concentration within the reactor; a multi-functional or independent instrument may be selected.

[0030] Furthermore, the pretreatment device 1 also includes a buffer solution preparation tank 131 for preparing a buffer solution. The buffer solution preparation tank 131 is connected to the reactor 11 via a pipe equipped with a buffer solution dosing pump 132 to deliver alkaline buffer solution into the reactor 11, thereby controlling the pH within the reactor 11 between 10.5 and 11.5. The buffer solution can be one or more of a soda ash solution, lime solution, and sodium hydroxide solution. In this embodiment, the calcium ions in the leachate are removed by utilizing carbonate ions in the sludge dewatering wastewater. Only a small amount of alkaline solution needs to be added to maintain the system in an alkaline environment, significantly reducing the amount of calcium removal agent used compared to conventional chemical dewatering methods. At the same time, this invention can also achieve the removal of most calcium pollutants in the leachate without generating other chemical substances, greatly reducing the difficulty of leachate treatment.

[0031] like Figure 1 As shown, the sludge adsorption device 2 includes a first filter tank 22 and a second filter tank 23 with identical and independent structures. The reactor 11 transports chemical sludge to the first filter tank 22 through a pipeline equipped with a spray pump 21, a first inlet valve 221, and a first spray head 223. The first filter tank 22 is equipped with a first filter bed 224 and a first level gauge 225. The first filter bed 224 is used to filter the chemical sludge. The first filter tank 22 is connected to the filter press tank 42 through a pipeline equipped with a flow meter 24, a first suspended solids detector 222, and a first filter 226 to transport the calcium removal wastewater filtrate to the filter press tank 42. Reactor 11 transports chemical sludge to filter tank 23 via a pipeline equipped with spray pump 21, inlet valve 231, and spray head 233. Filter tank 23 contains filter bed 234 and level gauge 235. Filter bed 234 is used for chemical sludge filtration. Filter tank 23 is connected to filter press tank 42 via a pipeline equipped with flow meter 24, suspended solids detector 232, and filter 236 to transport calcium-removed wastewater filtrate to filter press tank 42.

[0032] In this embodiment, the spray pump 21 is selected as a corrosion-resistant and high-lift screw pump, which is used to transfer the chemical sludge generated by the pretreatment device to the sludge filtration tank. The water inlet valve is used to realize the rotation of the two sludge filtration tanks, so as to control the water content of the garbage in the filter bed. The suspended matter detector is used to detect the sludge content of the water phase in the sludge filtration tank. The first spray head 223 and the second spray head 233 are both multiple, which are respectively covered above the first filter bed 224 and the second filter bed 234, and are divided into n spray zones, and the radiation radius of a single spray zone is 0.5-1 meter, so as to control the water content of garbage in each area of the filter bed. The first filter bed 224 and the second filter bed 234 are both filled with household garbage, and the filling height is 1-2 meters, which is used to filter the chemical sludge generated by the pretreatment device 1. In this embodiment, the filter bed filled with household garbage is used to filter the chemical sludge in the calcium removal wastewater, and there is no need to add a plate and frame filter press and other sludge dewatering devices, so that the overall operation electricity cost and equipment investment cost are relatively low. The first liquid level meter 225 and the second liquid level meter 235 are both pressure type liquid level sensors, which are used to measure the water phase liquid level height in the filter bed and represent the filter characteristics of the filter bed. The flow meter 24 is used to measure the outlet flow of the filter bed and control the spray flow of the spray pump. The first filter 226 and the second filter 236 are both bag filters, and pressure sensors are arranged before and after the filter, and the installation position is the filter bed outlet pipeline, which is used to intercept the chemical sludge penetrating through the filter bed and represent the sludge storage at the bottom of the filter bed.

[0033] As shown in Figure 2 The method for slowing down the sludge calcification of the anaerobic reactor in this embodiment includes the following steps: Step S1, the leachate and the sludge press filtrate are continuously and uniformly transported to the reactor 11 according to a ratio of 5:1, that is, the leachate inlet flow is 25 m3 / h, the calcium ion concentration is 2467 mg / L, and the temperature is 32℃; the press filtrate inlet flow is 5 m3 / h, the calcium ion concentration is 67 mg / L, and the alkalinity is 11054 mg / L (calculated as calcium carbonate).

[0034] The inner circulation pump 141 is a screw pump, and its flow rate and head meet the dosing requirements. The inner circulation pipe is additionally provided with a multifunctional detector 142, a sludge concentration detector, and an inner circulation flow meter 143. The multifunctional detector 142 is a pH and temperature two-in-one display instrument. The reactor 11 is provided with a buffer solution preparation tank 131. The buffer solution is a 40% sodium carbonate solution. The buffer solution dosing pump 132 is a diaphragm pump, and its flow rate and head meet the dosing requirements. The pH value of the multifunctional detector 142 is linked to the control of the buffer solution dosing pump 132. The reactor 11 is provided with a separate impeller type stirrer and an adjustable automatic control device. The effective volume of the reactor 11 is 180 m3, the reaction temperature is 27°C, the reaction pH value is 10.8-11, the sludge concentration is 5-12 g / L, the fast stirring speed of the stirrer 15 is 300 rpm, the fast stirring time is 3.5 h, the slow stirring speed is 75 rpm, the fast stirring time is 1.5 h, the hydraulic retention time is 5 h, and the calcium ion concentration of the pretreated effluent is 160 mg / L.

[0035] In step S2, the chemical sludge generated in the reactor 11 is transported to the filter tank through the spray pump 21 and the spray head, and the sludge-water separation is realized through the garbage-filled filter bed. The obtained filtrate enters the filter liquid tank 42, and the sludge concentration in the filtrate is controlled at 500-1500 mg / L. The filter residue is transferred to the garbage storage pit 31 by a grab bucket, mixed with the garbage in the garbage storage pit 31, and then transferred to a domestic garbage incinerator for joint treatment by a garbage crane 32. The spray area of the filter bed is divided into n zones, and the radiation radius of a single spray zone is 1 meter. When the pressure difference before and after the filter reaches 1.3 bar or the water phase liquid level height of the filter tank exceeds 0.5 meters, the filter bed or the spray area is replaced.

[0036] In step S3, the leachate and calcium removal wastewater are collected and transported. The leachate produced by the garbage storage pit 31 enters the leachate tank 41, and then is transported to the reactor 11 through the leachate lifting pump 411. The transportation flow rate of the leachate is linked to the transportation flow rate of the sludge filter liquid. In step S4, when the calcium ion concentration of the filter liquid in the filter liquid tank 42 is lower than 500 mg / L, the filter liquid is lifted to the UASB reactor by the anaerobic water pump 51 for joint treatment. According to the monitoring data, the calcium ion concentration of the water inlet of the UASB reactor is maintained at 200-350 mg / L for a long time. If the calcium ion concentration of the filter liquid in the filter liquid tank 42 exceeds 500 mg / L, the emergency reprocessing pump 421 is started to transport the filter liquid to the reactor 11 for secondary hardening treatment.

[0037] The present application realizes that most of the calcium pollutants in the landfill leachate are removed, and the calcium ion concentration of the treated pressure filtrate and leachate is less than 500 mg / L, the treatment difficulty is greatly reduced, the pressure filtrate and leachate can be treated by the conventional "anaerobic + biochemical + membrane" process, the pressure filtrate and leachate are treated cooperatively, the calcium ion concentration of the water inlet of the anaerobic reactor is ensured, and the stable operation of the anaerobic reactor and the problem of sludge calcification are mitigated, which is of great significance. The sludge pressure filtrate wastewater is utilized as a resource, the consumption of the calcium removal agent for the leachate is reduced, and the operation cost of the leachate treatment is reduced.

[0038] The above only describes the preferred embodiments of the present application, and the protection scope of the present application is not limited to the above-described embodiments only, and any technical solution belonging to the idea of the present application falls within the protection scope of the present application. It should be noted that, for ordinary skilled persons in the art, some improvements and refinements without departing from the principle of the present application should also be considered as the protection scope of the present application.

Claims

1. A system for mitigating calcification of sludge in an anaerobic reactor, characterized in that, include: The system comprises a pretreatment device (1), a sludge adsorption device (2), a sludge treatment device (3), a wastewater receiving device (4), and an anaerobic treatment device (5); the wastewater receiving device (4) includes a leachate tank (41) and a filter press tank (42); the pretreatment device (1) is connected to the sludge adsorption device (2), the leachate tank (41), and the filter press tank (42); the leachate tank (41) is connected to the sludge treatment device (3); the leachate produced by the sludge treatment device (3) enters the leachate tank (41); the sludge adsorption device (2) is connected to the filter press tank (42). The filtrate press tank (42) is connected to the anaerobic treatment device (5). The sludge filtrate and the leachate in the leachate tank (41) are added to the pretreatment device (1) in a preset ratio, so that the carbonate ions in the sludge filtrate neutralize the calcium ions in the leachate and form chemical sludge. The chemical sludge in the pretreatment device (1) is transported to the sludge adsorption device (2) to achieve filtration and separation. The filtrate produced by the sludge adsorption device (2) enters the filtrate press tank (42). The filtrate in the filtrate press tank (42) is sent to the anaerobic treatment device (5) or returned to the pretreatment device (1).

2. The system for mitigating sludge calcification in anaerobic reactors according to claim 1, characterized in that, The pretreatment device (1) includes a reactor (11), a stirrer (15) is provided inside the reactor (11), a conveying pipe for conveying sludge filtrate is provided on the upper part of the reactor (11), and a filtrate flow meter (12) is provided on the conveying pipe; a leachate lift pump (411), a No. 3 filter (412) and a leachate flow meter (413) are provided on the connecting pipe between the leachate tank (41) and the reactor (11).

3. The system for mitigating sludge calcification in anaerobic reactors according to claim 2, characterized in that, The pretreatment device (1) also includes an internal circulation pump (141), which is connected to the reactor (11) through a circulation pipeline, and the circulation pipeline is equipped with a multi-functional detector (142) and an internal circulation flow meter (143).

4. The system for mitigating sludge calcification in anaerobic reactors according to claim 2, characterized in that, The pretreatment device (1) also includes a buffer preparation tank (131), which is connected to the reactor (11) through a pipe with a buffer dosing pump (132) to deliver alkaline buffer solution into the reactor (11) so as to control the pH in the reactor (11) between 10.5 and 11.

5.

5. The system for mitigating calcification of anaerobic reactor sludge according to claim 2, characterized in that, The sludge adsorption device (2) includes a filter tank. The reactor (11) transports chemical sludge to the filter tank through a pipeline equipped with a spray pump (21), a control valve and a nozzle. The filter tank is equipped with a filter bed to achieve chemical sludge filtration. The filter tank is connected to the filtrate tank (42) through a pipeline equipped with a flow meter (24), a suspended solids detector and a filter to achieve filtrate transport to the filtrate tank (42).

6. The system for mitigating sludge calcification in an anaerobic reactor according to claim 5, characterized in that, The nozzles are multiple and cover the filter bed; the filter bed is filled with domestic waste with a filling height of 1 to 2 meters to filter the chemical sludge generated by the pretreatment device (1).

7. The system for mitigating calcification of anaerobic reactor sludge according to any one of claims 1 to 5, characterized in that, The sludge treatment device (3) includes a garbage storage pit (31) and a garbage crane (32), and the garbage storage pit (31) is connected to the leachate tank (41) through a pipeline; the anaerobic treatment device (5) includes an anaerobic inlet pump (51), a No. 3 suspended solids detector (52) and an anaerobic reactor (53), and a connecting pipeline with the anaerobic inlet pump (51) and the No. 3 suspended solids detector (52) is provided between the anaerobic reactor (53) and the filtrate tank (42).

8. A method for mitigating calcification of sludge in an anaerobic reactor, characterized in that, It is implemented based on the system for mitigating sludge calcification in anaerobic reactors as described in any one of claims 1 to 7, and includes the following steps: Step S1: The leachate and sludge filtrate are continuously and uniformly transported to the reactor (11) at a ratio of 4 to 6:

1. The stirrer (15) and the internal circulation pump (141) are turned on to accelerate the pretreatment reaction. The carbonate ions in the sludge filtrate neutralize the calcium ions in the leachate and form chemical sludge. During the reaction, the pH is controlled at 10.5 to 11.5, the temperature is 27 to 39°C, and the sludge concentration is 5 to 12 g / L. Step S2: The chemical sludge generated in the reactor (11) is transported to the filter tank by the spray pump (21) and the nozzle. The sludge and water are separated by the filter bed filled with garbage. The resulting filtrate enters the filtrate press tank (42). The filter residue is transferred to the garbage storage pit (31) by the grab bucket. After being mixed with the garbage in the garbage storage pit (31), it is transferred to the municipal solid waste incinerator for co-processing by the garbage crane (32). Step S3, collection and transportation of leachate and decalcification wastewater: The leachate produced in the garbage storage pit (31) enters the leachate tank (41) and is then transported to the reactor (11) by the leachate lift pump (411). The leachate transportation flow rate is interlocked with the sludge dewatering flow rate. Step S4: When the calcium ion concentration of the filtrate in the filter press tank (42) is less than 500 mg / L, the filtrate is pumped to the anaerobic reactor (53) by the anaerobic feed pump (51) for coordinated treatment; if the calcium ion concentration of the filtrate in the filter press tank (42) exceeds 500 mg / L, the emergency reprocessing pump (421) is turned on to transport the filtrate to the reactor (11) for secondary hardening treatment.

9. The method for mitigating calcification of anaerobic reactor sludge according to claim 8, characterized in that, In step S1, the agitator (15) is started in the order of fast stirring followed by slow stirring. The fast stirring speed is 200-400 rpm and the fast stirring time is 3-4 h. The slow stirring speed is 50-100 rpm and the slow stirring time is 1-2 h. The hydraulic residence time is 4-6 h.

10. The method for mitigating calcification of anaerobic reactor sludge according to claim 8, characterized in that, In step S2, the spray area of ​​the filter bed is divided into n zones, and the radiation radius of a single spray zone is 0.5 to 1 meter. When the pressure difference across the filter reaches 0.8 to 1.3 bar or the water level in the filter tank exceeds 0.5 meters, the filter bed or spray area needs to be replaced.

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