Wastewater treatment system and high CODcr wastewater treatment method

Abstract

The invention relates to a wastewater treatment technology, and discloses a wastewater treatment system and a high CODcr wastewater treatment method. The wastewater treatment system comprises a pretreatment unit, a biochemical treatment unit and an advanced treatment unit which are sequentially connected, the pretreatment unit comprises an adjusting tank, a pre-biochemical tank and a primary sedimentation tank which are connected in sequence, and the biochemical treatment unit comprises an anaerobic biochemical tank, an aerobic biochemical tank and an adsorption sedimentation tank which are connected in sequence; the advanced treatment unit comprises an ozone contact tank, a biological filter tank and an adsorption filter tank which are connected in sequence, the anaerobic biochemical tank is connected with the primary sedimentation tank, and the ozone contact tank is connected with the adsorption sedimentation tank; wherein the adsorption precipitation tank is provided with a precipitated sludge outlet connected with the pre-biochemical tank and the anaerobic biochemical tank. The wastewater treatment system and the wastewater treatment method have relatively high CODcr (Chemical Oxygen Demand) removal capability and relatively low operation cost.

Description

Technical Field

[0001] The present invention relates to wastewater treatment technology, and in particular, to a wastewater treatment system and a treatment system for high-CODcr wastewater using the wastewater treatment system. Background Art

[0002] Currently, not only is water resources scarce, but also there are increasingly serious water environmental pollution problems. Especially in the northwest region, chemical enterprises usually need to reuse the production wastewater after treatment. COD Cr is the chemical oxygen demand measured using potassium dichromate (K2Cr2O7) as an oxidant, and it is an important indicator of water pollution degree. It can be used as a comprehensive indicator of water body pollution by organic matter, and can also represent the content of organic matter in domestic sewage and industrial sewage. Therefore, chemical oxygen demand COD is strictly controlled as an important indicator in the sewage discharge standards of various countries.

[0003] Currently, the main domestic methods for COD Cr removal are flocculation and re-flocculation, and biochemical and re-biochemical treatment. However, chemical production wastewater usually has characteristics such as unstable water quality, large variation, and high CODcr. Conventional coagulation, sedimentation, and filtration can only remove 20-30% of the COD in the wastewater. Moreover, due to the presence of dissolved organic matter, it is not conducive to destroying the stability of the colloid, resulting in a significant decline in the removal effect and unable to meet the high removal rate requirements for COD Cr Therefore, how to efficiently remove the CODcr of wastewater is an urgent problem to be solved at present.

[0004] Although domestic and foreign have developed industrial wastewater treatment through biochemical treatment systems (hydrolysis acidification + secondary aerobic activated sludge + BAF biological aerated filter) and reclaimed water reuse systems (ultrafiltration + reverse osmosis membrane process treatment systems), problems such as rapid increase in the pressure difference of ultrafiltration membranes and reverse osmosis membranes, decrease in water production rate, frequent membrane cleaning, resulting in low on-line utilization rate of equipment and decline in water production capacity often occur. In addition, the adsorption materials for advanced wastewater treatment have low efficiency, low strength, large consumption, and high operating costs. Summary of the Invention

[0005] The purpose of the present invention is to overcome the problems of low removal rate of wastewater CODcr and high cost existing in the prior art, and to provide a wastewater treatment system and a treatment method for high-CODcr wastewater. The wastewater treatment system and method have a high CODcr removal ability and low operating costs.

[0006] To achieve the above object, a first aspect of the present invention provides a wastewater treatment system, which includes a pretreatment unit, a biochemical treatment unit, and a deep treatment unit connected in sequence; the pretreatment unit includes an adjustment tank, a prebiochemical tank, and a primary sedimentation tank connected in sequence, the biochemical treatment unit includes an anaerobic biochemical tank, an aerobic biochemical tank, and an adsorption sedimentation tank connected in sequence; the deep treatment unit includes an ozone contact tank, a biological filter, and an adsorption filter connected in sequence, the anaerobic biochemical tank is connected to the primary sedimentation tank, and the ozone contact tank is connected to the adsorption sedimentation tank; wherein, the adsorption sedimentation tank is provided with a sediment sludge outlet connected to the prebiochemical tank and the anaerobic biochemical tank.

[0007] Preferably, the adjustment tank and the prebiochemical tank are integrally arranged, a pretreatment overflow channel is formed between at least one side wall of the adjustment tank and the prebiochemical tank, an adjustment tank water inlet is arranged on the side and / or top of the adjustment tank, and a prebiochemical water outlet connected to the primary sedimentation tank is arranged in the middle and lower part of the side wall of the prebiochemical tank.

[0008] More preferably, an adjustment aeration structure is arranged at the bottom of the adjustment tank, and the sediment sludge outlet is connected to the top of the prebiochemical tank.

[0009] Further preferably, adsorption material inlets are arranged at the tops of both the anaerobic biochemical tank and the aerobic biochemical tank.

[0010] As a preferred embodiment, a plurality of the biological filters are arranged in parallel, and each biological filter is provided with a biological filter guide plate, a biological filter water inlet chamber located on one side of the biological filter guide plate, and a biological filter water outlet chamber located on the other side of the biological filter guide plate; a biological filter guiding channel is formed between one end of the biological filter guide plate connected to the bottom of the biological filter and the other end connected to the top of the biological filter, a biological filter water inlet connected to the ozone contact tank is arranged at the bottom of the biological filter water inlet chamber, and a biological filter water outlet connected to the adsorption filter is arranged at the bottom of the biological filter water outlet chamber.

[0011] Preferably, biological filter aeration structures and support fillers are arranged at the bottoms of both the biological filter water inlet chamber and the biological filter water outlet chamber; a biological filter turbulence structure extending towards the biological filter water inlet chamber is arranged on the biological filter guide plate.

[0012] More preferably, the biological filter further includes a biological filter backwashing structure, which includes a biological filter backwashing gas supply device, a biological filter backwashing liquid supply device, and a biological filter backwashing liquid overflow tank. The biological filter backwashing gas supply device is detachably connected to the biological filter aeration structure. The biological filter backwashing liquid supply device is detachably connected to the biological filter water inlet and the biological filter water outlet. The biological filter water inlet chamber and the biological filter water outlet chamber are respectively provided with the biological filter backwashing liquid overflow tank on at least one side thereof.

[0013] Further preferably, the biological filter backwashing structure further includes a biological filter backwashing effluent tank connected to the biological filter backwashing liquid overflow tank, and the biological filter backwashing effluent tank is connected to the pretreatment unit.

[0014] Specifically, there are multiple adsorption filters arranged in parallel. Each adsorption filter includes an adsorption filter water inlet area, a first adsorption filter water outlet area, and a second adsorption filter water outlet area arranged in sequence. An adsorption filter overflow channel is formed between the first adsorption filter water outlet area and the second adsorption filter water outlet area and the adsorption filter water inlet area on at least one side respectively. The bottom of the adsorption filter water inlet area is provided with an adsorption filter water inlet connected to the biological filter. The bottoms of both the first adsorption filter water outlet area and the second adsorption filter water outlet area are provided with adsorption filter water outlets.

[0015] More specifically, adsorption filter aeration structures are arranged in the adsorption filter water inlet area, the first adsorption filter water outlet area, and the second adsorption filter water outlet area. A baffle between the first adsorption filter water outlet area and the adsorption filter water inlet area is provided with an adsorption filter turbulence structure extending towards the adsorption filter water inlet area at the top.

[0016] Typically, the adsorption filter further includes an adsorption filter backwashing structure, which includes an adsorption filter backwashing gas supply device, an adsorption filter backwashing liquid supply device, and an adsorption filter backwashing liquid overflow tank. The adsorption filter backwashing gas supply device is detachably connected to the adsorption filter aeration structure. The adsorption filter backwashing liquid supply device is detachably connected to the adsorption filter filtration water inlet and the adsorption filter filtration water outlet. The adsorption filter filtration water inlet area, the first adsorption filter water outlet area, and the second adsorption filter water outlet area are respectively provided with the adsorption filter backwashing liquid overflow tank on at least one side thereof.

[0017] More typically, the adsorption filter backwashing structure further includes an adsorption filter backwashing effluent tank connected to the adsorption filter backwashing liquid overflow tank, and the adsorption filter backwashing effluent tank is connected to the pretreatment unit.

[0018] The second aspect of the present invention provides a method for treating wastewater with high COD Cr using the above wastewater treatment system. The treatment method includes the following steps:

[0019] S1. After the initial wastewater is aerated and adjusted in the adjustment tank, pre-biochemical treated in the pre-biochemical tank, and primary sedimentation treated in the primary sedimentation tank, it is anaerobically biochemically treated in the anaerobic biochemical tank in the presence of an adsorption material, aerobically biochemically treated in the aerobic biochemical tank in the presence of an adsorption material, and adsorption precipitation is carried out in the adsorption sedimentation tank to obtain a primary treated liquid and sediment sludge;

[0020] S2. The primary treated liquid is subjected to ozone contact in the ozone contact tank, filtered and microbially treated in the biological filter, and adsorption filtration in the adsorption filter;

[0021] During the process of this treatment method, part or all of the sediment sludge is recycled to the pre-biochemical tank.

[0022] Preferably, the raw material components of the adsorption material contain a main raw material, a binder, and a solvent; wherein, the binder contains the alcoholysis waste liquid in the process of producing polyvinyl alcohol by the alcoholysis of vinyl acetate polymerization, and / or the solvent contains the acetylene purification alkaline wastewater in the process of producing polyvinyl alcohol by the calcium carbide acetylene method.

[0023] Preferably, this treatment method further includes using part of the sediment sludge as part of the main raw material to prepare the adsorption material.

[0024] Preferably, the main raw material contains at least one of weakly caking coal, anthracite, coking coal, semi-coke, and bituminous coal, and the binder is selected from at least one of coal tar, liquid binder, and the alcoholysis waste liquid.

[0025] Through the above technical solutions, the beneficial effects of the present invention are as follows:

[0026] In the wastewater treatment system provided by the present invention, a pre-biochemical tank is arranged at the back end of the adjustment tank in the pretreatment unit, so that the sludge concentration in the pre-biochemical tank can be controlled at 500-1000 mg / L, which plays a role in adjusting and balancing the water quality, adding activated sludge, and preliminarily removing small-molecule organic substances, and improves the CODcr removal ability of the overall system; the advanced treatment unit adopts the form of an ozone contact tank, a biological filter, and an adsorption filter to enhance the advanced treatment effect, so that the effluent CODcr removal rate of the adsorption filter is high and the CODcr is stable; the sediment sludge in the adsorption sedimentation tank is recycled to the pre-biochemical tank and the anaerobic biochemical tank through the sediment sludge outlet, which is beneficial to further improving the CODcr removal ability of this treatment system.

[0027] Based on the above wastewater treatment system, the wastewater treatment method provided by the present invention enables anaerobic biochemical treatment and aerobic biochemical treatment to be carried out in the presence of an adsorption material, which helps the formation of zoogloea in the activated sludge system, improves the ability of the biochemical treatment unit to resist water quality fluctuations, and at the same time enhances the CODcr removal ability of the wastewater treatment system and reduces the operating cost.

[0028] Other features and advantages of the present invention will be described in detail in the subsequent specific implementation section. Brief Description of the Drawings

[0029] Figure 1 is a schematic structural diagram of a specific implementation of the wastewater treatment system in the present invention;

[0030] Figure 2 is a top view of a specific implementation of the regulating tank and prebiochemical tank in the present invention;

[0031] Figure 3 is Figure 2 a side view of the regulating tank and prebiochemical tank shown;

[0032] Figure 4 is a top view of a specific implementation of the biological filter in the present invention;

[0033] Figure 5 is Figure 4 a side view of the biological filter shown;

[0034] Figure 6 is a top view of a specific implementation of the adsorption filter in the present invention;

[0035] Figure 7 is Figure 6 a side view of the adsorption filter shown.

[0036] Description of the Reference Numerals

[0037] 1 - Pretreatment unit, 11 - Regulating tank, 12 - Prebiochemical tank, 13 - Primary sedimentation tank, 14 - Pretreatment overflow channel, 15 - Regulating aeration structure, 16 - Prebiochemical aeration structure;

[0038] 2 - Biochemical treatment unit, 21 - Anaerobic biochemical tank, 22 - Aerobic biochemical tank, 23 - Adsorption sedimentation tank;

[0039] 3 - Advanced treatment unit, 31 - Ozone contact tank, 32 - Biological filter, 321 - Biological filter flow - guiding plate, 322 - Biological filter influent chamber, 323 - Biological filter effluent chamber, 324 - Biological filter guiding channel, 325 - Biological filter aeration structure, 326 - Biological filter turbulence structure, 33 - Adsorption filter, 331 - Adsorption filter influent area, 332 - First adsorption filter effluent area, 333 - Second adsorption filter effluent area, 334 - Adsorption filter aeration structure, 335 - Adsorption filter turbulence structure, 336 - Adsorption filter overflow channel, 34 - Biological filter backwash liquid overflow trough, 35 - Adsorption filter backwash liquid overflow trough;

[0040] A - Initial wastewater, B - Adsorption material, C - Precipitated sludge, D - Produced water. Specific embodiments

[0041] The following combines the drawings to elaborate on the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not used to limit the present invention.

[0042] It should be understood that, for the convenience of describing the present invention and simplifying the description, the terms "top, bottom" refer to the up - down direction of each reaction tank in the wastewater treatment system, "front" refers to the influent end of each reaction tank in the wastewater treatment system, "rear" refers to the effluent end of each reaction tank in the treatment system, and "left, right" refer to both sides in the front - rear direction; the terms are based on the orientation or positional relationship shown in the drawings, rather than indicating or implying that the device or equipment referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention.

[0043] In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Therefore, the features defined with "first" and "second" may explicitly or implicitly include one or more of the said features.

[0044] The first aspect of the present invention provides a wastewater treatment system. Refer to Figure 1 , this wastewater treatment system includes a pretreatment unit 1, a biochemical treatment unit 2, and an advanced treatment unit 3 connected in sequence; the pretreatment unit 1 includes a regulating tank 11, a pre - biochemical tank 12, and a primary sedimentation tank 13 connected in sequence, the biochemical treatment unit 2 includes an anaerobic biochemical tank 21, an aerobic biochemical tank 22, and an adsorption sedimentation tank 23 connected in sequence; the advanced treatment unit 3 includes an ozone contact tank 31, a biological filter 32, and an adsorption filter 33 connected in sequence, the anaerobic biochemical tank 21 is connected to the primary sedimentation tank 13, and the ozone contact tank 31 is connected to the adsorption sedimentation tank 23; wherein, the adsorption sedimentation tank 23 is provided with a precipitated sludge outlet connected to the pre - biochemical tank 12 and the anaerobic biochemical tank 21.

[0045] In the present invention, corresponding valves can be provided on the pipelines involved, such as the connecting pipelines between the reaction tanks of the wastewater treatment system, the inlet pipeline of the regulating tank 11, and the outlet pipeline of the adsorption filter tank 33, etc., to control the operation and shutdown of the wastewater treatment system.

[0046] The wastewater treatment system provided by the present invention can be applied to the treatment of various wastewaters, including but not limited to high-CODcr industrial wastewater, high-salt industrial wastewater, domestic wastewater, etc., and is particularly suitable for the purification treatment of high-CODcr industrial wastewater; its specific treatment process is as follows:

[0047] S1. After the initial wastewater is aerated and adjusted in the regulating tank 11, pre-biochemical treatment is carried out in the pre-biochemical tank 12, and primary sedimentation treatment is carried out in the primary sedimentation tank 13, then anaerobic biochemical treatment is carried out in the anaerobic biochemical tank 21, aerobic biochemical treatment is carried out in the aerobic biochemical tank 22 in the presence of an adsorption material, and adsorption precipitation is carried out in the adsorption sedimentation tank 23 to obtain a primary treated liquid and sediment sludge.

[0048] S2. The primary treated liquid is subjected to ozone contact in the ozone contact tank 31, filtration and microbial treatment in the biological filter tank 32, and adsorption filtration in the adsorption filter tank 33.

[0049] During the process of this treatment method, part or all of the sediment sludge is recycled to the pre-biochemical tank 12 and the anaerobic biochemical tank 21.

[0050] In the wastewater treatment system provided by the present invention, a pre-biochemical tank 12 is arranged at the rear end of the regulating tank 11 in the pretreatment unit 1, so that the sludge concentration in the pre-biochemical tank 12 can be controlled at 500 - 1000 mg / L, which plays the role of regulating and balancing the water quality, adding activated sludge, and preliminarily removing small-molecule organic substances, and improves the CODcr removal ability of the overall system; the advanced treatment unit 3 adopts the form of an ozone contact tank 31, a biological filter tank 32, and an adsorption filter tank 33 to enhance the advanced treatment effect, so that the effluent CODcr removal rate of the adsorption filter tank 33 is high and the CODcr is stable; the sediment sludge in the adsorption sedimentation tank 23 is returned to the pre-biochemical tank 12 and the anaerobic biochemical tank 21 through the sediment sludge outlet, which is beneficial to further improving the CODcr removal ability of the treatment system.

[0051] In the present invention, the regulating tank 11, the pre-biochemical tank 12, and the primary sedimentation tank 13 can be sequentially connected by pipelines to realize the sequential aeration adjustment, pre-biochemical treatment, and primary sedimentation treatment of the wastewater. As a preferred embodiment, refer to Figure 2 and Figure 3, the regulating tank 11 and the pre - biochemical tank 12 are integrally arranged. A pretreatment overflow channel 14 is formed between at least one side wall of the regulating tank 11 and the pre - biochemical tank 12. The side and / or top of the regulating tank 11 is provided with a regulating tank water inlet, and the middle - lower part of the side wall of the pre - biochemical tank 12 is provided with a pre - biochemical water outlet connected to the primary sedimentation tank 13. After the initial waste liquid enters the regulating tank 11 through the regulating tank water inlet for aeration regulation, it enters the pre - biochemical tank 12 through the pretreatment overflow channel 14 for pre - biochemical treatment, and then enters the primary sedimentation tank 13 through the pre - biochemical water outlet, so as to realize the connection of the regulating tank 11 and the pre - biochemical tank 12 in a self - flowing series form, and the waste water forms a flow mode of entering from the bottom and flowing out from the top, which can extend the treatment time of the regulating tank 11 and the pre - biochemical tank 12 for the waste water, improve the treatment efficiency, and effectively save the space and floor area of the pretreatment unit 1. Exemplarily, the pre - biochemical tank 12 is arranged on at least one side of the side wall of the regulating tank 11 (for example Figure 2 on both sides of the regulating tank 11) to improve the pretreatment efficiency of the waste water.

[0052] In the present invention, the regulating tank 11 enables the waste water entering the regulating tank 11 to contact with air for aeration regulation. As a preferred implementation manner, an adjusting aeration structure 15 is arranged at the bottom of the regulating tank 11, and a pre - biochemical aeration structure 16 is arranged at the bottom of the pre - biochemical tank 12. The adjusting aeration structure 15 and the pre - biochemical aeration structure 16 can adopt structures such as aeration pipes and aeration plates suitable for the regulating tank 11, so as to aerate the waste water in the regulating tank 11 and the pre - biochemical tank 12 to balance the water quality, ensure the stability of subsequent treatment, and improve the treatment efficiency.

[0053] Further preferably, the tops of both the pre - biochemical tank 12 and the anaerobic biochemical tank 21 are connected to the sediment sludge outlet, so as to enable the sediment sludge flowing back to the pre - biochemical tank 12 and the anaerobic biochemical tank 21 to be better mixed with the waste water and improve the pre - biochemical treatment efficiency.

[0054] In the present invention, the pre - biochemical tank 12 can adopt a conventional biochemical reaction tank and the required materials (such as adsorbents, sediment sludge recycled from the adsorption sedimentation tank 23 to the pre - biochemical tank 12, etc.) to carry out a biochemical reaction on the waste water flowing out of the regulating tank 11. Its sludge concentration is controlled at 500 - 1000 mg / L, which plays a role in regulating and balancing the water quality, adding activated sludge, and preliminarily removing small - molecule organic substances, increasing the contact time between the activated sludge and the waste water, and improving the CODcr removal ability of the overall system; the primary sedimentation tank 13 can adopt a reaction tank for flocculation precipitation of the waste water flowing out of the pre - biochemical tank and the corresponding required materials (such as flocculants).

[0055] In the present invention, the anaerobic biochemical tank 21 and the aerobic biochemical tank 22 can adopt conventional biochemical reaction tanks and corresponding adsorption materials; the adsorption materials can be pre-placed in the anaerobic biochemical tank 21 and the aerobic biochemical tank 22, or can be added in real time during the wastewater treatment process. As a preferred embodiment, adsorption material inlets are provided at the tops of both the anaerobic biochemical tank 21 and the aerobic biochemical tank 22 to regularly add adsorption materials, so that anaerobic biochemical treatment and aerobic biochemical treatment are carried out in the presence of adsorption materials, which helps the formation of zoogloea in the activated sludge system, improves the anti-water quality fluctuation ability of the biochemical treatment unit 2, and at the same time improves the COD Cr removal ability of the wastewater treatment system and reduces the operating cost.

[0056] In the present invention, the adsorption material used in the aerobic biochemical tank 22 can be at least one of columnar, granular and powdery.

[0057] In the present invention, the biological filter 32 can adopt a conventional filter tank to reduce turbidity and suspended solids, and at the same time further remove CODcr. As a preferred embodiment, referring to Figure 4 and Figure 5 , a plurality of biological filters 32 are arranged in parallel, and a biological filter guide plate 321, a biological filter inlet chamber 322 located on one side of the biological filter guide plate 321, and a biological filter outlet chamber 323 located on the other side of the biological filter guide plate 321 are arranged in each biological filter 32; a biological filter guide channel 324 is formed between one end of the biological filter guide plate 321 connected to the bottom of the biological filter 32 and the top of the biological filter 32, a biological filter inlet is provided at the bottom of the biological filter inlet chamber 322 and connected to the ozone contact tank 31, and a biological filter outlet is provided at the bottom of the biological filter outlet chamber 323 and connected to the adsorption filter 33.

[0058] At this time, the wastewater flowing out of the ozone contact tank 31 enters from the bottom of the biological filter inlet chamber 322, then enters the biological filter outlet chamber 323 through the biological filter guide channel 324, and then enters the adsorption filter 33 from the biological filter outlet, so as to realize the connection of the inlet chamber and the outlet chamber in the biological filter 32 in a self-flow series form, and the wastewater forms a downward-in and upward-out flow mode, which can extend the treatment time of the wastewater in the biological filter inlet chamber 322 and the biological filter outlet chamber 323 and improve the filtration efficiency of the biological filter.

[0059] Among them, a plurality of biological filters 32 can be integrally arranged adjacent to each other as shown in Figure 4 to further improve the floor space of the biological filter 32.

[0060] In the present invention, the adsorption material used in the biological filter 32 is columnar, and the diameter is about 2-5 mm.

[0061] In the present invention, preferably, biological filter aeration structures 325 and support fillers are provided at the bottoms of both the biological filter inlet chamber 322 and the biological filter outlet chamber 323. Generally, the biological filter aeration structures 325 are not operated and are only used for gas backwashing. Among them, the biological filter aeration structures 325 can adopt structures such as aeration pipes and aeration plates suitable for the biological filter 32, so as to equalize the water quality in the biological filter inlet chamber 322 and improve the treatment efficiency of the biological filter for filtration. The support fillers can adopt cobblestones, gravel, etc.

[0062] In the present invention, the biological filter deflector 321 can adopt a deflector arranged vertically or obliquely. Preferably, a biological filter turbulence structure 326 extending towards the biological filter inlet chamber 322 is provided on the biological filter deflector 321, so that when the wastewater flows in the biological filter 32, a mixed flow movement in multiple directions is generated, which can further improve the filtration treatment efficiency of the biological filter.

[0063] In the present invention, the biological filter inlet chamber 322 and the biological filter outlet chamber 323 need to be periodically backwashed, for example, by gas backwashing and / or liquid backwashing, to clean the aged biofilm on the surface of the adsorption material in the biological filter 32 and the suspended solids accumulated in the tank. Preferably, the biological filter 32 further includes a biological filter backwashing structure, which includes a biological filter backwashing gas supply device, a biological filter backwashing liquid supply device, and a biological filter backwashing liquid overflow tank 34. The biological filter backwashing gas supply device is detachably connected to the biological filter aeration structure 325, the biological filter backwashing liquid supply device is detachably connected to the biological filter inlet and the biological filter outlet, and the biological filter inlet chamber 322 and the biological filter outlet chamber 323 are respectively provided with the biological filter backwashing liquid overflow tank 34 on at least one side thereof.

[0064] In the present invention, the biological filter backwashing liquid overflow tanks 34 corresponding to the biological filter inlet chamber 322 and the biological filter outlet chamber 323 can be interconnected or independently arranged; the height of the biological filter backwashing liquid overflow tank 34 is generally higher than the top height of the biological filter deflector 321 to reduce the mutual interference of the backwashing liquid in the two areas of the biological filter inlet chamber 322 and the biological filter outlet chamber 323.

[0065] Specifically, the specific process of backwashing the biological filter inlet chamber 322 and the biological filter outlet chamber 323 can be as follows: First, close the inlet and outlet of the corresponding area (which can be controlled by the inlet valve and the outlet valve), connect the biological filter backwashing gas supply device to the biological filter aeration structure 325 and open it, so that the gas enters the corresponding area from the biological filter aeration structure 325, rubs with the adsorption material in the water in this area, and then emits from the tops of the biological filter inlet chamber 322 and the biological filter outlet chamber 323. Control the expansion rate of the adsorption material in this area (10 - 30%). After washing for a certain time, close the biological filter backwashing gas supply device and the intake valve; connect the biological filter backwashing liquid supply device to the biological filter inlet and the biological filter outlet (which can be controlled by the connecting branch and the liquid inlet valve) and open it, input the flushing liquid into the corresponding area to contact with the adsorption material, control the expansion rate of the adsorption material for liquid backwashing, and the flushing liquid overflows through the biological filter backwashing liquid overflow tank 34 and is discharged.

[0066] Further preferably, the biological filter backwashing structure further includes a biological filter backwashing effluent tank connected to the biological filter backwashing liquid overflow tank 34, and the biological filter backwashing effluent tank is connected to the pretreatment unit 1 to enter the backwashing liquid overflowing into the biological filter backwashing liquid overflow tank 34 into the pretreatment unit 1 for treatment.

[0067] In the present invention, the adsorption filter 33 can reduce suspended solids and organic matters that are difficult to biochemically treat. As a preferred embodiment, refer to Figure 6 and Figure 7 , there are multiple adsorption filters 33 arranged in parallel. Each adsorption filter 33 includes an adsorption filter inlet area 331, a first adsorption filter outlet area 332, and a second adsorption filter outlet area 333 arranged in sequence. An adsorption filter overflow channel 336 is formed between the first adsorption filter outlet area 332 and the second adsorption filter outlet area 333 and the adsorption filter inlet area 331 on at least one side respectively; an adsorption filter inlet is provided at the bottom of the adsorption filter inlet area 331 and is connected to the biological filter 32, and adsorption filter outlets are provided at the bottoms of both the first adsorption filter outlet area 332 and the second adsorption filter outlet area 333. Among them, the multiple adsorption filters 33 can be arranged adjacent to each other as Figure 6 shown to further improve the occupied space of the adsorption filter 33.

[0068] At this time, the wastewater flowing out of the biological filter 32 enters from the bottom of the adsorption filter inlet area 331, enters the first adsorption filter outlet area 332 and the second adsorption filter outlet area 333 through the adsorption filter overflow channel 336, and then flows out from the adsorption filter outlet, so as to realize the connection in series by gravity flow within the adsorption filter 33, and the wastewater forms a form in which the upward flow in the adsorption filter inlet area 331 is combined with the downward flow in the first adsorption filter outlet area 332 and the second adsorption filter outlet area 333. Compared with the downward flow adsorption filter, the upward flow adsorption filter can increase the contact time between the wastewater and the adsorption material and improve the CODcr removal effect of the filter; compared with the upward flow adsorption filter, the downward flow adsorption filter has a better effect of removing SS (suspended solids) and reducing turbidity; in the present invention, the adsorption filter 33 adopts a form combining upward flow and downward flow, further improving the adsorption and filtration effects.

[0069] In the present invention, the adsorption material used in the adsorption filter 33 is in the shape of irregular particles, and the diameter is about 6-30 mesh. In the present invention, preferably, an adsorption filter aeration structure 334 is provided in the adsorption filter inlet area 331, the first adsorption filter outlet area 332 and the second adsorption filter outlet area 333; the adsorption filter aeration structure 334 generally does not operate and is only used for gas backwashing. Among them, the adsorption filter aeration structure 334 can adopt structures such as an air pipe and an aeration plate suitable for the adsorption filter 33 to improve the treatment efficiency of adsorption filtration.

[0070] In the present invention, the partition between the first adsorption filter outlet area 332 and the adsorption filter inlet area 331 can be a vertically or obliquely arranged partition. Preferably, an adsorption filter turbulence structure 335 extending towards the adsorption filter inlet area 331 is provided at the top of the partition between the first adsorption filter outlet area 332 and the adsorption filter inlet area 331, so that the wastewater generates a mixed flow movement in multiple directions when flowing in the adsorption filter 33, which can further improve the efficiency of adsorption filtration treatment.

[0071] In the present invention, the influent zone 331 of the adsorption filter, the effluent zone 332 of the first adsorption filter, and the effluent zone 333 of the second adsorption filter need to be backwashed regularly, for example, by gas backwashing and / or liquid backwashing, to clean the suspended solids accumulated on the surface area of the adsorption material in the adsorption filter 33 and the suspended solids accumulated in the pool. Preferably, the adsorption filter 33 further includes an adsorption filter backwashing structure, which includes an adsorption filter backwashing gas supply device, an adsorption filter backwashing liquid supply device, and an adsorption filter backwashing liquid overflow tank 35. The adsorption filter backwashing gas supply device is detachably connected to the adsorption filter aeration structure 334, and the adsorption filter backwashing liquid supply device is detachably connected to the adsorption filter influent port and the adsorption filter effluent port. The influent zone 331 of the adsorption filter, the effluent zone 332 of the first adsorption filter, and the effluent zone 333 of the second adsorption filter are respectively provided with an adsorption filter backwashing liquid overflow tank 35 on at least one side thereof; so that the influent zone 331 of the adsorption filter, the effluent zone 332 of the first adsorption filter, and the effluent zone 333 of the second adsorption filter can perform gas backwashing and / or liquid backwashing independently of each other without interference.

[0072] In the present invention, the adsorption filter backwashing liquid overflow tanks 35 corresponding to the influent zone 331 of the adsorption filter, the effluent zone 332 of the first adsorption filter, and the effluent zone 333 of the second adsorption filter can be interconnected or independently arranged; the height of the adsorption filter backwashing liquid overflow tank 35 is generally higher than the top height of the partition between the three zones to reduce the mutual interference of the backwashing liquid in the three zones. Specifically, the specific process of backwashing the influent zone 331 of the adsorption filter, the effluent zone 332 of the first adsorption filter, and the effluent zone 333 of the second adsorption filter can be as follows: first, close the influent port and the effluent port of the corresponding zone (controlled by the influent valve and the effluent valve), connect the adsorption filter backwashing gas supply device to the adsorption filter aeration structure 334 and open it, so that gas enters the corresponding zone from the adsorption filter aeration structure 334, rubs against the adsorption material in the water in the zone, and then emits from the top of the corresponding zone. Control the expansion rate (10 - 30%) of the adsorption material in the zone. After washing for a certain time, close the adsorption filter backwashing gas supply device and the intake valve; connect the adsorption filter backwashing liquid supply device to the adsorption filter influent port and the adsorption filter effluent port (controlled by the connecting branch and the liquid inlet valve) and open it, input the flushing liquid into the corresponding zone to contact the adsorption material, control the expansion rate of the adsorption material for liquid backwashing, and the flushing liquid overflows through the adsorption filter backwashing liquid overflow tank 35 and is discharged.

[0073] Further preferably, the adsorption filter backwashing structure further includes an adsorption filter backwashing effluent tank connected to the adsorption filter backwashing liquid overflow tank 35, and the adsorption filter backwashing effluent tank is connected to the pretreatment unit 1 to send the backwashing liquid overflowing into the adsorption filter backwashing liquid overflow tank 35 into the pretreatment unit 1 for treatment.

[0074] Based on the above wastewater treatment system, a second aspect of the present invention provides a method for treating high-COD Cr wastewater. Using the above-mentioned wastewater treatment system, the treatment method includes the following steps:

[0075] S1. After the initial wastewater is subjected to aeration adjustment in the regulation tank 11, pre-biological treatment in the pre-biological treatment tank 12, and primary sedimentation treatment in the primary sedimentation tank 13, it is subjected to anaerobic biochemical treatment in the anaerobic biochemical tank 21 in the presence of an adsorption material, aerobic biochemical treatment in the aerobic biochemical tank 22 in the presence of an adsorption material, and adsorption precipitation in the adsorption sedimentation tank 23 to obtain a primary treated liquid and sediment sludge;

[0076] S2. The primary treated liquid is subjected to ozone contact in the ozone contact tank 31, filtration and microbial treatment in the biological filter 32, and adsorption filtration in the adsorption filter 33;

[0077] During the process of this treatment method, part or all of the sediment sludge is recycled to the pre-biological treatment tank 12 and the anaerobic biochemical tank 21.

[0078] The produced water COD obtained by the treatment method of the present invention Cr is stable and lower than 50 mg / L, and the ultrafiltration + reverse osmosis membrane of the recycling system operates stably

[0079] According to the present invention, preferably, the raw material components of the adsorption material contain a main raw material, a binder, and a solvent; wherein, the binder contains the alcoholysis waste liquid in the process of producing polyvinyl alcohol by the polymerization and alcoholysis of vinyl acetate and / or the solvent contains the acetylene purification alkaline wastewater in the process of producing polyvinyl alcohol by the calcium carbide acetylene method. In this preferred embodiment, the adsorption material can not only realize the comprehensive recycling of the waste liquid in the polyvinyl alcohol production process, avoid waste of resources, but also reduce the manufacturing cost, and in the application to high-COD Cr wastewater treatment process, it can achieve a high CODcr removal rate, improve the wastewater treatment efficiency, and reduce the operating cost of wastewater treatment.

[0080] According to the present invention, preferably, this treatment method further includes using part of the sediment sludge as part of the main raw material to prepare the adsorption material. In this preferred embodiment, recycling the sediment sludge in the wastewater treatment process to the preparation of the adsorption material not only realizes the comprehensive utilization of the sludge generated by the system, but also further reduces the manufacturing cost of the adsorption material.

[0081] According to the present invention, preferably, the main raw material contains at least one of weakly caking coal, anthracite, coking coal, semi-coke, and bituminous coal, and the binder is selected from at least one of coal tar, liquid binder, and the alcoholysis waste liquid.

[0082] Exemplarily, the preparation method of the adsorbent material includes: drying the main raw material (the content of precipitated sludge is within 50% by weight, preferably 20 - 30% by weight) at 100 - 120°C for 30 - 120 minutes, grinding the main raw material with a mill so that the fineness of the main raw material meets the sieve passing rate of more than 95% through a 325 - mesh Tyler standard sieve, and the fineness of the binder meets the sieve passing rate of more than 90% through a 100 - mesh Tyler standard sieve; putting the main raw material into a kneading device for thorough mixing for 10 - 30 minutes, keeping the temperature of the kneading device at 80 - 95°C, adding the binder and continuing to knead for 10 - 20 minutes, evenly spraying and adding acetylene - purified alkaline wastewater while kneading, and then continuing to knead for 5 - 15 minutes to obtain a kneaded material; placing the kneaded material in an extruder and extruding and forming under the condition of an extrusion strength of 10 - 30 MPa to obtain formed particles; carbonizing the formed particles at a temperature of 500 - 700°C for 20 - 40 minutes to obtain carbonized particles, and carrying out an activation reaction of the carbonized particles with water vapor in an activation furnace at a temperature of 850 - 950°C for an activation time of 30 - 120 minutes to obtain the adsorbent material.

[0083] The present invention will be described in detail below through examples.

[0084] In the following examples, the iodine value was measured according to "GB / T 7702.7 - 2008 Test Methods for Coal - Based Granular Activated Carbon - Determination of Iodine Adsorption Value", the strength was measured according to "GB / T 7702.3 - 2008 Test Methods for Coal - Based Granular Activated Carbon - Determination of Strength", the pH value was measured according to "GB / T 7702.16 - 1997 Test Methods for Coal - Based Granular Activated Carbon - Determination of pH Value", the floating rate was measured according to "GB / T7702.17 - 2008 Test Methods for Coal - Made Granular Activated Carbon - Determination of Floating Rate", the water - soluble substances were measured according to "GB / T 7701.2 - 2008 Test Methods for Coal - Made Granular Activated Carbon - Determination of Water - Soluble Substances in Appendix C", and the methylene blue adsorption value was

[0085] measured according to "GB / T 7702.6 - 2008 Test Methods for Coal - Made Granular Activated Carbon - Determination of Methylene Blue Adsorption Value", and the ash content was measured according to the method of "GB / T 7702.15 - 2008 Test Methods for Coal - Based Granular Activated Carbon - Determination of Ash Content"; the COD Cr was measured according to the method of "HJ / T399 - 2007 Water Quality - Determination of Chemical Oxygen Demand - Fast Digestion Spectrophotometry"; the COD of the waste liquid Cr removal rate was calculated through the following formula:

[0086] COD Cr Removal rate = [(COD before adsorption Cr - COD after adsorption Cr ) / COD before adsorption Cr * 100%.

[0087] In the following examples, the alcoholysis waste liquid is sourced from the workshop of a polyvinyl alcohol production enterprise in Inner Mongolia for producing polyvinyl alcohol by vinyl acetate polymerization alcoholysis; the acetylene purification alkaline wastewater is sourced from the workshop of a polyvinyl alcohol production enterprise in Inner Mongolia for producing polyvinyl alcohol by calcium carbide acetylene method; the initial waste liquid is sourced from a polyvinyl alcohol production enterprise in Inner Mongolia; the weakly caking coal is purchased from Yixin Coal Industry Co., Ltd. in Datong City, the anthracite is purchased from Shanxi Sentai Energy Development Co., Ltd., the bituminous coal and coking coal are purchased from Shaanxi Zhongyuan Coal Transportation and Storage Co., Ltd., the semi-coke is purchased from Xingguang Coal Chemical Co., Ltd. in Hutubi County, the coal tar is purchased from Jinda Chemical Co., Ltd. in Dongguang County, the polyvinyl alcohol with a polymerization degree greater than 1700 is purchased from a polyvinyl alcohol production enterprise in Inner Mongolia with the brand number 1788, the sodium carboxymethyl cellulose is purchased from Jinan Duanxing Chemical Technology Co., Ltd. with the brand number FH9, and the rest of the raw materials and reagents are all conventional commercially available products.

[0088] In the following examples, unless otherwise specified, the amounts of raw materials are calculated based on dry weight.

[0089] Example 1

[0090] The wastewater treatment system includes a pretreatment unit 1, a biochemical treatment unit 2, and a deep treatment unit 3 connected in sequence; the pretreatment unit 1 includes an adjustment tank 11, a prebiochemical tank 12, and a primary sedimentation tank 13 connected in sequence. The adjustment tank 11 and the prebiochemical tank 12 are integrally arranged. The prebiochemical tank 12 is located on both sides of the adjustment tank 11, and a pretreatment overflow channel 14 is formed between the side wall of the adjustment tank 11 and the prebiochemical tank 12. The side and / or top of the adjustment tank 11 is provided with an adjustment tank water inlet, the bottom of the adjustment tank 11 is provided with an adjustment aeration structure 15, the middle and lower part of the side wall of the prebiochemical tank 12 is provided with a prebiochemical water outlet connected to the primary sedimentation tank 13, and the bottom of the prebiochemical tank 12 is provided with a prebiochemical aeration structure 16; the biochemical treatment unit 2 includes an anaerobic biochemical tank 21, an aerobic biochemical tank 22, and an adsorption sedimentation tank 23 connected in sequence. The tops of both the anaerobic biochemical tank 21 and the aerobic biochemical tank 22 are provided with adsorption material inlets. The anaerobic biochemical tank 21 is connected to the primary sedimentation tank 13, and the bottom of the adsorption sedimentation tank 23 is provided with a sediment sludge outlet connected to the tops of the prebiochemical tank 12 and the anaerobic biochemical tank 21; the deep treatment unit 3 includes an ozone contact tank 31, a biological filter 32, and an adsorption filter 33 connected in sequence. The ozone contact tank 31 is connected to the adsorption sedimentation tank 23. The biological filters 32 are multiple and are arranged in parallel and integrally. Each biological filter 32 is provided with a biological filter guide plate 321, a biological filter water inlet chamber 322 located on one side of the biological filter guide plate 321, and a biological filter water outlet chamber 323 located on the other side of the biological filter guide plate 321. One end of the biological filter guide plate 321 is connected to the bottom of the biological filter 32, and a biological filter guiding channel 324 is formed between the other end and the top of the biological filter 32. The bottom of the biological filter water inlet chamber 322 is provided with a biological filter water inlet connected to the ozone contact tank 31, the bottom of the biological filter water outlet chamber 323 is provided with a biological filter water outlet connected to the adsorption filter 33, the bottoms of both the biological filter water inlet chamber 322 and the biological filter water outlet chamber 323 are provided with a biological filter aeration structure 325 and supporting fillers, the biological filter guide plate 321 is provided with a biological filter turbulence structure 326 extending towards the biological filter water inlet chamber 322, and the biological filter 32 further includes a biological filter backwashing structure. The biological filter backwashing structure includes a biological filter backwashing gas supply device, a biological filter backwashing liquid supply device, a biological filter backwashing liquid overflow tank 34, and a biological filter backwashing liquid outlet tank connected to the biological filter backwashing liquid overflow tank 34. The biological filter backwashing gas supply device is detachably connected to the biological filter aeration structure 325, the biological filter backwashing liquid supply device is detachably connected to the biological filter water inlet and the biological filter water outlet, the biological filter water inlet chamber 322 and the biological filter water outlet chamber 323 are respectively provided with the biological filter backwashing liquid overflow tank 34 on at least one side thereof, and the biological filter backwashing liquid outlet tank is connected to the adjustment tank 11;There are multiple adsorption filters 33 arranged in parallel. Each adsorption filter 33 includes an adsorption filter water inlet area 331, a first adsorption filter water outlet area 332, and a second adsorption filter water outlet area 333 arranged in sequence. An adsorption filter overflow channel 336 is formed between the first adsorption filter water outlet area 332 and the second adsorption filter water outlet area 333 and the adsorption filter water inlet area 331 on at least one side respectively; an adsorption filter water inlet connected to the biological filter 32 is provided at the bottom of the adsorption filter water inlet area 331, adsorption filter water outlets are provided at the bottoms of both the first adsorption filter water outlet area 332 and the second adsorption filter water outlet area 333, an adsorption filter aeration structure 334 is provided in each of the adsorption filter water inlet area 331, the first adsorption filter water outlet area 332, and the second adsorption filter water outlet area 333, and an adsorption filter turbulence structure 335 extending towards the adsorption filter water inlet area 331 is provided at the top of the partition between the first adsorption filter water outlet area 332 and the adsorption filter water inlet area 331; the adsorption filter 33 further includes an adsorption filter backwashing structure, and the adsorption filter backwashing structure includes an adsorption filter backwashing gas supply device, an adsorption filter backwashing liquid supply device, an adsorption filter backwashing liquid overflow tank 35, and an adsorption filter backwashing liquid outlet tank connected to the adsorption filter backwashing liquid overflow tank 35. The adsorption filter backwashing gas supply device is detachably connected to the adsorption filter aeration structure, the adsorption filter backwashing liquid supply device is detachably connected to the adsorption filter water inlet and the adsorption filter water outlet, adsorption filter backwashing liquid overflow tanks 35 are provided on at least one side of each of the adsorption filter water inlet area 331, the first adsorption filter water outlet area 332, and the second adsorption filter water outlet area 333, and the adsorption filter backwashing liquid outlet tank is connected to the regulation tank 11.;

[0091] Example 2

[0092] The process of treating wastewater using the wastewater treatment system provided in Example 1 is as follows:

[0093] S1. The initial wastewater A enters the regulation tank 11 through the regulation tank water inlet, is aerated and regulated, then enters the pre-biological treatment tank 12 through the pretreatment overflow channel 14 for pre-biological treatment (the sludge concentration in the pre-biological treatment tank 12 is controlled at 500 - 1000 mg / L), then enters the primary sedimentation tank 13 through the pre-biological treatment water outlet for primary sedimentation treatment, and undergoes anaerobic biological treatment in the anaerobic biological treatment tank 21 in the presence of the adsorption material B, aerobic biological treatment in the aerobic biological treatment tank 22 in the presence of the adsorption material B, and adsorption precipitation in the adsorption sedimentation tank 23 to obtain a primary treated liquid and sediment sludge C;

[0094] S2. Subject the primary treatment liquid to ozone contact in the ozone contact tank 31. The wastewater flowing out of the ozone contact tank 31 enters from the bottom of the biological filter inlet chamber 322 and then enters the biological filter outlet chamber 323 through the biological filter guiding channel 324 for filtration treatment (the adsorption material is columnar with a diameter of about 2 - 5 mm). After that, it enters from the bottom of the adsorption filter inlet area 331 through the biological filter outlet, and then enters the first adsorption filter outlet area 332 and the second adsorption filter outlet area 333 through the adsorption filter overflow channel 336 for adsorption filtration (the adsorption material is irregular granular), and then flows out from the adsorption filter outlet to obtain the produced water D;

[0095] During the process of this treatment method, add the adsorption material B into the anaerobic biochemical tank 21 and the aerobic biochemical tank 22 regularly from the adsorption material inlet. Part of the precipitated sludge C in step S1 is recycled from the precipitated sludge outlet to the pre - biochemical tank 12, part is recycled from the precipitated sludge outlet to the anaerobic biochemical tank 21, and part is used to prepare the adsorption material B. When the biological filter 32 needs to be cleaned, first close the inlet and outlet of the corresponding area (which can be controlled by the inlet valve and the outlet valve), connect the biological filter backwashing gas supply device to the biological filter aeration structure 325 and open it, so that the gas enters the corresponding area from the biological filter aeration structure 325, rubs with the adsorption material in the water in this area and then emits from the tops of the biological filter inlet chamber 322 and the biological filter outlet chamber 323, control the expansion rate of the adsorption material in this area (10 - 30%). After cleaning for a certain time, close the biological filter backwashing gas supply device and the inlet valve; connect the biological filter backwashing liquid supply device to the biological filter inlet and the biological filter outlet (which can be controlled by the connecting branch and the liquid inlet valve) and open it, input the flushing liquid into the corresponding area to contact with the adsorption material, control the expansion rate of the adsorption material for liquid backwashing, and the flushing liquid overflows and is discharged through the biological filter backwashing liquid overflow tank 34. When the adsorption filter 33 needs to be cleaned, first close the inlet and outlet of the corresponding area (which can be controlled by the inlet valve and the outlet valve), connect the adsorption filter backwashing gas supply device to the adsorption filter aeration structure 334 and open it, so that the gas enters the corresponding area from the adsorption filter aeration structure 334, rubs with the adsorption material in the water in this area and then emits from the top of the corresponding area, control the expansion rate of the adsorption material in this area (10 - 30%). After cleaning for a certain time, close the adsorption filter backwashing gas supply device and the inlet valve; connect the adsorption filter backwashing liquid supply device to the adsorption filter inlet and the adsorption filter outlet (which can be controlled by the connecting branch and the liquid inlet valve) and open it, input the flushing liquid into the corresponding area to contact with the adsorption material, control the expansion rate of the adsorption material for liquid backwashing, and the flushing liquid overflows and is discharged through the adsorption filter backwashing liquid overflow tank 35.

[0096] The preparation method of adsorbent material B in Example 2 is as follows: drying the precipitated sludge C obtained in step S1 to obtain dried sludge, drying the dried sludge, anthracite and coking coal at 100°C for 120 min, grinding the dried sludge, anthracite and coking coal by a grinding machine so that the fineness of the main raw materials meets the screening rate of more than 95% on a 325-mesh Taylor standard sieve; stirring and dissolving 0.05 kg of polyvinyl alcohol solid, 0.1 kg of sodium carboxymethyl cellulose and 2 kg of deionized water at 90°C for at least 2 h to obtain a liquid binder, grinding the liquid binder and alcoholysis waste liquid so that the fineness meets the screening rate of more than 90% on a 100-mesh Taylor standard sieve; placing 1.65 kg of dried sludge, 2.47 kg of anthracite and 2.48 kg of coking coal in a mixing bowl; mixing the dried sludge, anthracite and ... The mixture was put into a kneading device for thorough mixing for 30 minutes, the temperature of the kneading device was maintained at 80°C, 1.58 kg of dissolved liquid binder (temperature was about 90°C) and 0.32 kg of alcoholysis waste liquid were added, and the kneading was continued for 20 minutes. While kneading, 0.5 kg of acetylene was evenly sprayed and added to purify alkaline wastewater, and the kneading was continued for 5 minutes to obtain a kneaded material; the kneaded material was placed in an extruder and extruded at an extrusion strength of 30 MPa to obtain molded particles; the molded particles were carbonized at a temperature of 600°C for 20 minutes to obtain carbonized particles, and the carbonized particles were activated with water vapor in an activation furnace at a temperature of 850°C for 120 minutes to obtain adsorption material B.

[0097] Example 3

[0098] Wastewater treatment was carried out according to the method of Example 2, except that the preparation method of adsorbent material B was replaced by:

[0099] The anthracite and coking coal are dried at 100 °C for 120 min, and then ground by a grinding machine so that the fineness of the main raw materials meets the requirement that the sieve passing rate through a 325-mesh Tyler standard sieve is greater than 95%; 0.05 kg of solid polyvinyl alcohol, 0.1 kg of sodium carboxymethyl cellulose and 2 kg of deionized water are stirred and dissolved at 90 °C for at least 2 h to prepare a liquid binder. The liquid binder and the alcoholysis waste liquid are ground so that their fineness meets the requirement that the sieve passing rate through a 100-mesh Tyler standard sieve is greater than 90%; 3.3 kg of anthracite and 3.3 kg of coking coal are put into a kneading device and fully mixed for 30 min. The temperature of the kneading device is maintained at 80 °C. After adding 1.58 kg of the dissolved liquid binder (at about 90 °C) and 0.32 kg of the alcoholysis waste liquid, kneading is continued for 20 min. During kneading, 0.5 kg of acetylene purification alkaline wastewater is evenly sprayed and added, and then kneading is continued for 5 min to obtain a kneaded material; the kneaded material is placed in an extruder and extruded into formed particles under the condition of an extrusion strength of 30 MPa; the formed particles are carbonized at 600 °C for 20 min to obtain carbonized particles, and the carbonized particles are subjected to an activation reaction with water vapor in an activation furnace at 850 °C for 120 min to obtain the adsorption material B.

[0100] Test Example 1

[0101] The iodine value, strength, pH, floating rate, water-soluble substances, methylene blue adsorption value, and ash content of the adsorption material B in Test Examples 2-3 were detected, and the results are shown in Table 1.

[0102] Detect the COD of the primary treatment liquid after adsorption precipitation treatment Cr , and calculate the COD relative to the initial wastewater A Cr Removal rate, and the results are shown in Table 1.

[0103] Table 1

[0104]

[0105] In Test Examples 2 and 3, the dosage ratios of the main raw materials, the binder, and the acetylene purification alkaline wastewater are the same. The only difference is that in the preparation process of the adsorption material B in Test Example 2, a part of the main raw materials are replaced by the precipitated sludge C obtained in step S1. As can be seen from the data in Table 1, Test Example 2 can achieve adsorption material characteristics and COD Cr Removal rate similar to those of Test Example 3, realize the comprehensive utilization of the sludge generated by the wastewater treatment system, and effectively reduce the operation cost of wastewater treatment.

[0106] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0107] In addition, it should be noted that each of the specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0108] Furthermore, any combination can be made among various different embodiments of the present invention as long as it does not violate the idea of the present invention, and it should equally be regarded as the content disclosed by the present invention.

Claims

1. A wastewater treatment system, characterized in that, The wastewater treatment system includes a pretreatment unit (1), a biochemical treatment unit (2), and an advanced treatment unit (3) connected in sequence; the pretreatment unit (1) includes an adjustment tank (11), a pre-biochemical tank (12), and a primary sedimentation tank (13) connected in sequence, the biochemical treatment unit (2) includes an anaerobic biochemical tank (21), an aerobic biochemical tank (22), and an adsorption sedimentation tank (23) connected in sequence; the advanced treatment unit (3) includes an ozone contact tank (31), a biological filter (32), and an adsorption filter (33) connected in sequence, the anaerobic biochemical tank (21) is connected to the primary sedimentation tank (13), and the ozone contact tank (31) is connected to the adsorption sedimentation tank (23); wherein, the adsorption sedimentation tank (23) is provided with a sediment sludge outlet connected to the pre-biochemical tank (12) and the anaerobic biochemical tank (21).

2. The wastewater treatment system according to claim 1, wherein, The adjustment tank (11) and the pre-biochemical tank (12) are integrally arranged, a pretreatment overflow channel (14) is formed between at least one side wall of the adjustment tank (11) and the pre-biochemical tank (12), an adjustment tank water inlet is arranged on the side part and / or the top of the adjustment tank (11), and a pre-biochemical water outlet connected to the primary sedimentation tank (13) is arranged in the middle and lower part of the side wall of the pre-biochemical tank (12).

3. The wastewater treatment system according to claim 1, characterized in that, An adjustment aeration structure (15) is arranged at the bottom of the adjustment tank (11), a pre-biochemical aeration structure (16) is arranged at the bottom of the pre-biochemical tank (12), and the tops of both the pre-biochemical tank (12) and the anaerobic biochemical tank (21) are respectively connected to the sediment sludge outlet.

4. The wastewater treatment system according to any one of claims 1 to 3, characterized in that Adsorption material inlets are arranged at the tops of both the anaerobic biochemical tank (21) and the aerobic biochemical tank (22).

5. The wastewater treatment system according to any one of claims 1 to 3, characterized in that There are multiple biological filters (32) arranged in parallel. Each biological filter (32) is internally provided with a biological filter guide plate (321), a biological filter water inlet chamber (322) located on one side of the biological filter guide plate (321), and a biological filter water outlet chamber (323) located on the other side of the biological filter guide plate (321); a biological filter guiding channel (324) is formed between one end of the biological filter guide plate (321) connected to the bottom of the biological filter (32) and the top of the biological filter (32). A biological filter water inlet connected to the ozone contact tank (31) is arranged at the bottom of the biological filter water inlet chamber (322), and a biological filter water outlet connected to the adsorption filter (33) is arranged at the bottom of the biological filter water outlet chamber (323).

6. The wastewater treatment system according to claim 5, characterized in that, Biological filter aeration structures (325) and supporting fillers are arranged at the bottoms of both the biological filter water inlet chamber (322) and the biological filter water outlet chamber (323). A biological filter turbulence structure (326) extending towards the biological filter water inlet chamber (322) is arranged on the biological filter guide plate (321).

7. The wastewater treatment system according to claim 6, wherein The biological filter (32) further includes a biological filter backwashing structure, which includes a biological filter backwashing gas supply device, a biological filter backwashing liquid supply device, and a biological filter backwashing liquid overflow tank (34). The biological filter backwashing gas supply device is detachably connected to the biological filter aeration structure (325). The biological filter backwashing liquid supply device is detachably connected to the biological filter water inlet and the biological filter water outlet. The biological filter water inlet chamber (322) and the biological filter water outlet chamber (323) are respectively provided with the biological filter backwashing liquid overflow tank (34) on at least one side thereof. Preferably, the biological filter backwashing structure further includes a biological filter backwashing liquid discharge tank connected to the biological filter backwashing liquid overflow tank (34), and the biological filter backwashing liquid discharge tank is connected to the pretreatment unit (1).

8. The wastewater treatment system according to any one of claims 1 to 3, characterized in that There are multiple adsorption filters (33) arranged in parallel. Each adsorption filter (33) includes an adsorption filter water inlet area (331), a first adsorption filter water outlet area (332), and a second adsorption filter water outlet area (333) arranged in sequence. An adsorption filter overflow channel (336) is formed between the first adsorption filter water outlet area (332) and the second adsorption filter water outlet area (333) and the adsorption filter water inlet area (331) on at least one side respectively. The bottom of the adsorption filter water inlet area (331) is provided with an adsorption filter water inlet connected to the biological filter (32). The bottoms of both the first adsorption filter water outlet area (332) and the second adsorption filter water outlet area (333) are provided with adsorption filter water outlets.

9. The wastewater treatment system according to claim 8, wherein Adsorption filter aeration structures (334) are provided in the adsorption filter water inlet area (331), the first adsorption filter water outlet area (332), and the second adsorption filter water outlet area (333). At the top of the partition between the first adsorption filter water outlet area (332) and the adsorption filter water inlet area (331), an adsorption filter flow disturbance structure (335) extending towards the adsorption filter water inlet area (331) is provided.

10. The wastewater treatment system according to claim 9, characterized in that, The adsorption filter (33) further includes an adsorption filter backwashing structure, which includes an adsorption filter backwashing gas supply device, an adsorption filter backwashing liquid supply device, and an adsorption filter backwashing liquid overflow tank (35). The adsorption filter backwashing gas supply device is detachably connected to the adsorption filter aeration structure (334). The adsorption filter backwashing liquid supply device is detachably connected to the adsorption filter filtration water inlet and the adsorption filter filtration water outlet. The adsorption filter filtration water inlet area (331), the first adsorption filter water outlet area (332), and the second adsorption filter water outlet area (333) are respectively provided with the adsorption filter backwashing liquid overflow tank (35) on at least one side thereof. Preferably, the adsorption filter backwashing structure further includes an adsorption filter backwashing liquid discharge tank connected to the adsorption filter backwashing liquid overflow tank (35), and the adsorption filter backwashing liquid discharge tank is connected to the pretreatment unit (1).

11. A method for treating wastewater with high COD Cr is characterized in that Adopt the wastewater treatment system according to any one of claims 1 to 10, and the treatment method includes the following steps: S1. After the initial wastewater is subjected to aeration adjustment in the regulating tank (11), pre-biological treatment in the pre-biological treatment tank (12), and primary sedimentation treatment in the primary sedimentation tank (13), it is subjected to anaerobic biochemical treatment in the anaerobic biochemical tank (21) in the presence of an adsorption material, aerobic biochemical treatment in the aerobic biochemical tank (22) in the presence of an adsorption material, and adsorption sedimentation in the adsorption sedimentation tank (23) to obtain a primary treated liquid and sediment sludge; S2. The primary treated liquid is subjected to ozone contact in the ozone contact tank (31), filtration and microbial treatment in the biological filter (32), and adsorption filtration in the adsorption filter (33); During the process of this treatment method, part or all of the sediment sludge is recycled to the pre-biological treatment tank (12) and the anaerobic biochemical tank (21); Preferably, the raw material components of the adsorption material contain a main raw material, a binder, and a solvent; wherein, the binder contains the alcoholysis waste liquid in the process of producing polyvinyl alcohol by the alcoholysis of vinyl acetate polymerization and / or the solvent contains the acetylene purification alkaline wastewater in the process of producing polyvinyl alcohol by the calcium carbide acetylene method; Preferably, this treatment method further includes using part of the sediment sludge as part of the main raw material to prepare the adsorption material; Preferably, the main raw material contains at least one of weakly caking coal, anthracite, coking coal, semi-coke, and bituminous coal, and the binder is selected from at least one of coal tar, liquid binder, and the alcoholysis waste liquid.

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