Efficient sewage treatment system for high-calcium wastewater

Abstract

The utility model provides an efficient sewage treatment system for high-calcium wastewater, which comprises a biological decalcification unit and a biochemical treatment unit, the bottom of a first anaerobic tank of the biological decalcification unit is communicated with the top of a first anoxic tank, the bottom of the first anoxic tank is communicated with a first aerobic tank, and the first aerobic tank is communicated with a first sedimentation tank; the bottom of a second anaerobic tank in the biochemical treatment unit is communicated with the top of a second anoxic tank, and the bottom of the second anoxic tank is communicated with a second aerobic tank; the first sedimentation tank is communicated with the upper part of the second anaerobic tank. The sewage treatment system is based on two-stage A2O, most of calcium ions in water are removed through first-stage A2O, decalcification treatment is carried out, a basis is provided for COD removal, denitrification and other biochemistry through second-stage A2O, the biological treatment effect of high-calcium wastewater is improved, meanwhile, sludge is screened and concentrated through the cyclone device, residual sludge is subjected to resourceful treatment, and the treatment effect of the high-calcium wastewater is improved. And the effects of reducing the cost, improving the efficiency and recycling resources are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the sewage treatment technical field, especially to a kind of high-efficiency sewage treatment system for high-calcium wastewater. BACKGROUND

[0002] High-calcium wastewater mainly comes from petroleum processing, non-ferrous metal smelting, sulfuric acid production, printing and dyeing, papermaking, chemical industry and pesticide industry, among which the most typical is gelatin production wastewater.Most of high-calcium wastewater is mainly treated by physical, chemical and biological methods or a combination of several methods, and problems such as easy expansion of activated sludge, large amount of sludge discharge and low microbial activity are presented in the treatment process.

[0003] High-calcium wastewater contains a large amount of Ca 2+ , which inhibits the growth of microorganisms, shows toxic effects on activated sludge microorganisms, and affects the application of biological treatment; high concentration of calcium ions can weaken the carbon balance in water, reduce the pH of the system, inhibit the nitrification reaction and reduce the denitrification efficiency; calcium ions can also combine with phosphorus in wastewater to form part of calcium hydrogen phosphate, causing a decrease in phosphorus in water and inhibiting microbial growth; at the same time, a large amount of CaCO3 is generated, which hinders the sludge volume ratio (SV 30 ), adsorption capacity, mass transfer capacity and sludge age of activated sludge, and also leads to a huge amount of secondary waste of sewage treatment - residual sludge discharge.

[0004] For the problem of excessive calcium ions in high-calcium wastewater, the existing technology mostly adds chemical agents to form a precipitate to achieve calcium removal, but this method requires a large amount of chemical agents, increases the cost of wastewater treatment, reduces the treatment efficiency, and may also cause secondary pollution. For the standard discharge of high-calcium wastewater, research on the biological treatment of high-calcium wastewater is increasing, but single biological treatment of high-calcium wastewater sometimes cannot achieve good treatment effect, so how to improve the efficiency of biological treatment of high-calcium wastewater has become one of the focuses of high-calcium wastewater treatment. CONTENT OF THE UTILITY MODEL

[0005] The present application provides a kind of high-efficiency sewage treatment system for high-calcium wastewater to solve the problems of related technologies, and the technical scheme is as follows:

[0006] In the first aspect, the present application provides a kind of high-efficiency sewage treatment system for high-calcium wastewater, including biological decalcification unit and biochemical treatment unit, the biological decalcification unit includes first anaerobic tank, first anoxic tank and first aerobic tank and first sedimentation tank, and the biochemical treatment unit includes second anaerobic tank, second anoxic tank and second aerobic tank.

[0007] The bottom of the first anaerobic tank is communicated with the top of the first anoxic tank, the bottom of the first anoxic tank is communicated with the first aerobic tank, and the first aerobic tank is communicated with the first sedimentation tank.

[0008] The bottom of the second anaerobic tank is communicated with the top of the second anoxic tank, and the bottom of the second anoxic tank is communicated with the second aerobic tank.

[0009] The first sedimentation tank is communicated with the upper part of the second anaerobic tank.

[0010] In an embodiment, the first anaerobic tank, the first anoxic tank, the first aerobic tank, the second anaerobic tank, the second anoxic tank and the second aerobic tank are all filled with activated sludge.

[0011] In an embodiment, the first aerobic tank and the second aerobic tank are respectively provided with an aeration device.

[0012] In an embodiment, the aeration device comprises a lift aeration pipe.

[0013] In an embodiment, the aeration pipe in the first aerobic tank is a perforated aeration pipe.

[0014] In an embodiment, the aeration pipe in the second aerobic tank is a microporous aeration pipe.

[0015] In an embodiment, the first sedimentation tank is provided with a gas-lift reflux device, and the other end of the gas-lift reflux device is communicated with the first anaerobic tank.

[0016] In an embodiment, a hydrocyclone is installed on the sludge-water mixture reflux pipe of the gas-lift reflux device.

[0017] In an embodiment, the second aerobic tank is further provided with a second sedimentation tank and a clean water tank.

[0018] In an embodiment, the second sedimentation tank is provided with a gas-lift reflux device, and the other end of the gas-lift reflux device is communicated with the second anaerobic tank.

[0019] In an embodiment, the first anaerobic tank, the first anoxic tank, and the second anaerobic tank, and the second anoxic tank are provided with a stirring unit.

[0020] In an embodiment, the first aerobic tank and the second aerobic tank are respectively provided with a pH control unit.

[0021] In an embodiment, the high-efficiency wastewater treatment system for high-calcium wastewater comprises two or more groups of biological decalcification units and biochemical treatment units, and the two or more groups of biological decalcification units and biochemical treatment units are in parallel.

[0022] The advantages or beneficial effects of the above technical solutions at least include:

[0023] The application is directed to the problems of high cost, low efficiency, low microbial activity, large amount of residual sludge discharge, and high cost of residual sludge treatment of high-calcium wastewater treatment, and provides a high-efficiency wastewater treatment system for high-calcium wastewater. 2 O, removes most of the calcium ions in the water through the first A 2 O, and performs decalcification treatment, so that the second A 2 O removes COD and provides a basis for denitrification and other biochemicals, improves the biological treatment effect of high-calcium wastewater, and at the same time, through the cyclone device, the sludge is screened and concentrated, the residual sludge is resourcefully treated, and the effects of reducing cost, improving efficiency, and resource recycling are achieved.

[0024] The above summary is only for the purpose of the description and is not intended to limit in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of the application will be readily apparent to those skilled in the art by reference to the drawings and the following detailed description. BRIEF DESCRIPTION OF DRAWINGS

[0025] In the drawings, like reference numerals refer to same or similar functionalities throughout the several views. The drawings are not necessarily to scale. It is to be understood that the drawings only depict certain embodiments in accordance with the disclosure and should not be considered limiting of the scope of the disclosure.

[0026] Figure 1 The structure diagram of the high-efficiency wastewater treatment system for high-calcium wastewater of the utility model; wherein 1, biological decalcification unit, 101, first anaerobic tank, 102, first anoxic tank, 103, first aerobic tank, 104, first sedimentation tank, 2, biochemical treatment unit, 201, first anaerobic tank, 202, first anoxic tank, 203, first aerobic tank, 3, second sedimentation tank, 4, clear water tank, 5, gas stripping reflux device. DETAILED DESCRIPTION

[0027] In the following, only certain exemplary embodiments are described briefly. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the application. Therefore, the drawings and description are considered to be exemplary in nature rather than limiting.

[0028] EMBODIMENT

[0029] As Figure 1As shown, the application provides a high-efficiency sewage treatment system for high-calcium wastewater, which comprises a biological decalcification unit 1 and a biochemical treatment unit 2. The biological decalcification unit 1 comprises a first anaerobic tank 101, a first anoxic tank 102, a first aerobic tank 103, and a first sedimentation tank 104. The biochemical treatment unit 2 comprises a second anaerobic tank 201, a second anoxic tank 202, a second aerobic tank 203, and a second sedimentation tank 204.

[0030] The bottom of the first anaerobic tank 101 is in communication with the top of the first anoxic tank 102. The bottom of the first anoxic tank 102 is in communication with the first aerobic tank 103. The first aerobic tank 103 is in communication with the first sedimentation tank 104.

[0031] The bottom of the second anaerobic tank 201 is in communication with the top of the second anoxic tank 202. The bottom of the second anoxic tank 202 is in communication with the second aerobic tank 203.

[0032] The first sedimentation tank 104 is in communication with the upper part of the second anaerobic tank 201.

[0033] In the present embodiment, activated sludge is filled in the first anaerobic tank 101, the first anoxic tank 102, the first aerobic tank 103, the second anaerobic tank 201, the second anoxic tank 202, and the second aerobic tank 203. The sludge concentration of the first aerobic tank 103 is 35-45 g / L, and the MLVSS / MLSS is 15-25%. The sludge concentration of the second aerobic tank 203 is 4-6 g / L, and the MLVSS / MLSS is 65-80%. The reduction of calcium ions in the biological decalcification unit 1 reduces the inhibition of microorganisms, promotes the enrichment of microorganisms, and greatly reduces the sludge concentration of the second aerobic tank 203 in the biochemical treatment unit 2, and increases the content of organic sludge, so that the sludge load is increased, and the treatment efficiency is enhanced.

[0034] The high-efficiency sewage treatment system for high-calcium wastewater of the application is composed of two levels of A 2 O, wherein the first level A 2 O is a biological decalcification unit for decalcification treatment of high-calcium wastewater, and the second level A 2 O is a biochemical treatment unit for removing organic matter, nitrogen, phosphorus, and other pollutants in high-calcium wastewater. The biological decalcification unit promotes the deposition of calcium ions in high-calcium wastewater, removes calcium ions, and does not need to add a large amount of chemical agents, effectively reducing the cost of calcium removal of high-calcium wastewater and avoiding secondary pollution. And through the biological decalcification unit, the calcium ions can be reduced, the combination of calcium ions and phosphorus can be reduced, enough phosphorus elements can be reserved for the growth of microorganisms in the subsequent biochemical system, and the growth of microorganisms can be promoted. At the same time, the toxic effect of calcium ions on microorganisms in the subsequent biochemical system is reduced, which is conducive to improving the efficiency of the subsequent biochemical treatment unit, improving the activity of microorganisms, increasing the water quantity, and improving the efficiency of biological treatment of high-calcium wastewater.

[0035] The wastewater enters the biological decalcification unit 1, first enters the first anaerobic tank 101 and the first anoxic tank 102, and the first anaerobic tank 101 and the first anoxic tank 102 mainly function to stabilize the microbial community, adjust the influent, and simultaneously serve as the front end of the first stage A 2 O, and part of the nitrogen and organic matter can be removed through denitrification.

[0036] Further, the first anaerobic tank and the first anoxic tank are provided with a stirring unit; the wastewater and sludge are fully mixed in the first anaerobic tank 101 and the first anoxic tank 102 through the stirring machine, so as to pretreat and adjust the wastewater.

[0037] The wastewater enters the first anoxic tank 102 and then enters the first aerobic tank 103; the first aerobic tank 103 is mainly used for decalcification of the wastewater, and the first aerobic tank 103 is provided with a pH control unit. The pH of the first aerobic tank 103 is controlled to be 8-9; the pH control unit adjusts the pH of the first aerobic tank 103 by using a sodium hydroxide solution. The mass fraction of the sodium hydroxide solution is 2%-10%. If the water entering the biological decalcification unit 1 is alkaline wastewater with a pH of 11-12, there is no need to adjust the pH by additionally adding sodium hydroxide.

[0038] The first aerobic tank 103 is provided with an aeration device (not marked in the figure); the aeration device is arranged at the bottom of the water environment, air is supplied through a pipeline by a blower, and the air volume is controlled. The aeration device includes a lifting aeration pipe; high-calcium wastewater is prone to cause blockage of the aeration pipe due to its characteristics, affecting the dissolved oxygen efficiency, and the lifting aeration pipe is adopted for aeration, which facilitates regular cleaning and maintenance of the aeration pipe. The perforated aeration pipe is used for continuous aeration in the first aerobic tank 103, and the air volume is controlled to be 25-30 m 3 / h, and the dissolved oxygen is 1-3 mg / L.

[0039] Firstly, the microorganisms can adsorb calcium ions in the water through intracellular and extracellular enrichment and surface adsorption; the surface of the activated sludge is negatively charged, and part of the calcium ions can also be removed through electrostatic adsorption. Secondly, the flocculent structure of the activated sludge provides attachment points and binding sites for calcium carbonate crystals, the first aerobic tank 103 introduces air into the wastewater through the perforated aeration form, breaks the carbonic acid balance, and thus promotes the combination of calcium ions and carbonate ions in the wastewater to generate calcium carbonate precipitate; the pH control unit adjusts the pH of the system by using sodium hydroxide, controls the carbonic acid balance in the wastewater, and makes the calcium ions precipitate in the form of calcium carbonate in the first aerobic tank 103, so that the activated sludge adsorbs the calcium carbonate crystal precipitate to remove most of the calcium ions in the wastewater.

[0040] The wastewater treated by the first aerobic tank 103 enters the first sedimentation tank 104. The first sedimentation tank 104 is provided with a gas stripping reflux device 5, and the other end of the gas stripping reflux device 5 is communicated with the first anaerobic tank 101. The biological decalcification unit 1 comprises the first sedimentation tank 104, the sludge after sedimentation has good compression performance, high dewatering efficiency, improves the treatment efficiency of the residual sludge, and reduces the energy consumption. At the same time, the gas stripping reflux device 5 is arranged in the first sedimentation tank 104, and the gas stripping device is used for refluxing the high-calcium sludge with high calcium content and large quality.

[0041] The sludge-water mixture reflux pipe of the gas stripping reflux device 5 is provided with a hydrocyclone. The use of the cyclone device 5 can increase the calcium content in the sludge, which is beneficial to resource recycling. The use of the hydrocyclone device screens the reflux sludge, and the hydrocyclone device screens the sludge according to the quality of the sludge, so that the residual sludge discharged from the underflow port has higher calcium content, which is convenient for calcium recycling; at the same time, the sludge discharged from the overflow port has higher organic matter, which is refluxed to the first anaerobic tank 101 for partial biochemical treatment.

[0042] The gas supply amount of the first sedimentation tank 104 is 15-25 m 3 / h, the reflux amount is 100%-150%, the hydrocyclone is installed on the reflux pipeline to screen the sludge, and the ratio of the reflux sludge to the residual sludge after screening by the cyclone is 2-4:6-8, the residual sludge after treatment has good compression performance and high calcium content, which is more than 90%, and is used for resource recycling.

[0043] The removal rates of nitrogen and organic matter in the wastewater treated by the biological decalcification unit 1 are 10%-30%. The wastewater continues to enter the biochemical treatment unit 2, and first enters the second anaerobic tank 201 and the second anoxic tank 202. The biochemical treatment unit 2 is used for biochemical treatment of high-calcium wastewater, and realizes the functions of removing organic matter and denitrification and phosphorus removal in the wastewater.

[0044] The second anaerobic tank 201 and the second anoxic tank 202 are also provided with stirring units; the wastewater entering the second anaerobic tank 201 and the second anoxic tank 202 is fully mixed with the sludge under the action of the stirrer, so as to pretreat and adjust the wastewater.

[0045] Through the treatment of the biological decalcification unit 1, the calcium ion content in the wastewater is reduced, which reduces the inhibition of microorganisms, so that the advantage microorganisms enriched in the second anaerobic tank 201 and the second anoxic tank 202 remove the organic matter and nitrogen in the wastewater.

[0046] The wastewater enters the second aerobic tank 203 from the second anoxic tank 202; the second aerobic tank 203 is provided with a pH control unit. The pH of the second aerobic tank 203 is controlled to be 7-8.

[0047] The second aerobic tank 203 is provided with an aeration device (not shown in the figure). The aeration device is arranged at the bottom of the water environment, and air is supplied by a blower through a pipeline, and the air volume is controlled. The aeration device comprises a lifting aeration pipe. The high-calcium wastewater is prone to cause blockage of the aeration pipe due to its characteristics, affecting the oxygen dissolution efficiency. The lifting aeration pipe is adopted for aeration, which facilitates regular cleaning and maintenance of the aeration pipe. The second aerobic tank 203 is continuously aerated by using a microporous aeration pipe, and air is blown by a blower. The air volume of the blower is 22-28 m 3 / h, and the dissolved oxygen is 2-4 mg / L.

[0048] After the wastewater passes through the second anaerobic tank 201 and the second anoxic tank 202, the wastewater and sludge are fully mixed to make full contact, and the enriched denitrifying bacteria remove nitrate nitrogen in the water and consume part of the organic matter. After the wastewater enters the second aerobic tank 203, the dissolved oxygen and pH feedback control are performed to control the dissolved oxygen concentration in the system to oxidize the organic matter in the wastewater, promote the nitrification reaction, control the pH range to reduce the production of carbonate, and meet the pH conditions required by the nitrification reaction at the same time. The nitrification mixed liquid is returned to the secondary anoxic tank for denitrification reaction. Preferably, the dissolved oxygen and pH feedback control are performed by a PLC automatic control system. The removal rates of organic matter and nitrogen in the wastewater treated by the biochemical treatment unit 2 are 70%-90%.

[0049] The second aerobic tank is further provided with a second sedimentation tank 3 and a clear water tank 4. The wastewater treated by the second aerobic tank 203 enters the second sedimentation tank 3 for sedimentation, and the supernatant can be discharged to the clear water tank 4. The effluent of the clear water tank 4 can be reused.

[0050] As one of the embodiments, the second sedimentation tank 3 is provided with a gas stripping reflux device 5 (not shown in the figure), and the other end of the gas stripping reflux device 5 is communicated with the second anaerobic tank 201. Part of the sludge is returned to the second anaerobic tank 201.

[0051] Further, the high-efficiency wastewater treatment system for high-calcium wastewater comprises two or more groups of biological decalcification units and biochemical treatment units, and the two or more groups of biological decalcification units and biochemical treatment units are parallel. When one group needs to be cleaned and maintained due to blockage, the normal operation of the wastewater treatment can be ensured, and the normal production activities can be ensured.

[0052] By collecting the activated sludge of the first aerobic tank 103 and the second aerobic tank 203 to compare the properties, the sludge properties in the first aerobic tank 103 of the biological decalcification unit 1 and the second aerobic tank 203 of the biochemical treatment unit 2 are quite different. Since the first aerobic tank 103 of the biological decalcification unit 1 plays a role of decalcification, the sludge in the tank presents white color due to calcium precipitation, while the sludge of the second aerobic tank 203 presents normal yellow-brown color. Therefore, the interception of calcium ions by the biological decalcification unit 1 ensures that the sludge biomass of the later biochemical treatment unit 2 is higher and the biological activity is good.

[0053] Therefore, by the efficient sewage treatment system for high-calcium wastewater of the present application, based on two-stage A 2 O, the first-stage A 2 O removes most of the calcium ions in the water to perform decalcification treatment, and the second-stage A 2 O removes COD and provides a basis for denitrification and other biochemical treatment, improves the biological treatment effect of high-calcium wastewater, and at the same time, the cyclone device is used to screen and concentrate the sludge, and the remaining sludge is treated as a resource, so as to reduce the cost, improve the efficiency, and achieve the effect of resource recycling.

[0054] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, different embodiments or examples described in the present specification and the features of different embodiments or examples can be combined and combined by those skilled in the art without contradiction.

[0055] 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 the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0056] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of various changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A high efficient sewage treatment system for high calcium wastewater, characterized in that, The system comprises a biological decalcification unit and a biochemical treatment unit, the biological decalcification unit comprises a first anaerobic tank, a first anoxic tank, a first aerobic tank and a first sedimentation tank, and the biochemical treatment unit comprises a second anaerobic tank, a second anoxic tank, a second aerobic tank and a second sedimentation tank. The bottom of the first anaerobic tank is in communication with the top of the first anoxic tank, the bottom of the first anoxic tank is in communication with the first aerobic tank, and the first aerobic tank is in communication with the first sedimentation tank. The bottom of the second anaerobic tank is in communication with the top of the second anoxic tank, and the bottom of the second anoxic tank is in communication with the second aerobic tank. The first sedimentation tank is in communication with the upper part of the second anaerobic tank.

2. The efficient sewage treatment system for high-calcium wastewater according to claim 1, wherein the first anaerobic tank, the first anoxic tank, the first aerobic tank, the second anaerobic tank, the second anoxic tank and the second aerobic tank are all filled with activated sludge.

3. The efficient sewage treatment system for high-calcium wastewater according to claim 1, wherein the first aerobic tank and the second aerobic tank are respectively provided with an aeration device, and the aeration device comprises a lifting aeration pipe.

4. The efficient sewage treatment system for high-calcium wastewater according to claim 3, wherein the aeration pipe in the first aerobic tank is a perforated aeration pipe, and the aeration pipe in the second aerobic tank is a microporous aeration pipe.

5. The efficient sewage treatment system for high-calcium wastewater according to claim 1, wherein the first sedimentation tank is provided with a gas stripping reflux device, and the other end of the gas stripping reflux device is in communication with the first anaerobic tank.

6. The efficient sewage treatment system for high-calcium wastewater according to claim 5, wherein a hydrocyclone is installed on the sludge-water mixture reflux pipe of the gas stripping reflux device.

7. The efficient sewage treatment system for high-calcium wastewater according to claim 1, wherein the second aerobic tank is further provided with a second sedimentation tank and a clean water tank.

8. The efficient sewage treatment system for high-calcium wastewater according to claim 7, wherein the second sedimentation tank is provided with a gas stripping reflux device, and the other end of the gas stripping reflux device is in communication with the second anaerobic tank.

9. The efficient sewage treatment system for high-calcium wastewater according to claim 1, wherein the first anaerobic tank, the first anoxic tank, the second anaerobic tank and the second anoxic tank are all provided with a stirring unit.

10. The efficient sewage treatment system for high-calcium wastewater according to claim 1, wherein the biological decalcification unit and the biochemical treatment unit in the efficient sewage treatment system for high-calcium wastewater are two or more groups, and the two or more groups of the biological decalcification unit and the biochemical treatment unit are parallel. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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