A wastewater treatment system and method of anaerobic coupling with electric stimulation and synergistic bacteria-algae desulfurization

Abstract

The application provides a wastewater treatment system and method for anaerobic coupling and electric stimulation synergistic bacteria-algae desulfurization, which comprises a primary anaerobic reactor and a secondary anaerobic reactor; the primary anaerobic reactor comprises an anaerobic fluidized state zone and a desulfurization reaction zone, the anaerobic fluidized state zone is filled with a filler carrier, the sulfate in the wastewater is converted into sulfide by sulfate-reducing bacteria attached to the filler carrier in the anaerobic fluidized state zone, the desulfurization reaction zone is filled with microalgae and desulfurization bacteria, oxygen is generated by photosynthesis of the microalgae in the desulfurization reaction zone, the oxygen is used by the desulfurization bacteria and the sulfide in the wastewater is converted into sulfur at the same time, the effluent outlet of the desulfurization reaction zone is connected with the secondary anaerobic reactor, and the organic matter in the wastewater is converted into methane in the secondary anaerobic reactor. The primary anaerobic reactor is used as a desulfurization process, the wastewater is recycled by desulfurization to avoid inhibition of anaerobic microorganisms in the downstream reactor by sulfide, and the wastewater enters the secondary anaerobic reactor again to degrade organic pollutants, so that the biodegradability of the wastewater is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wastewater treatment, in particular to a wastewater treatment system and method of anaerobic coupling electric stimulation and desulfurization of bacteria and algae. BACKGROUND

[0002] At present, anaerobic biological technology has been widely used in the field of industrial organic wastewater treatment. Due to the characteristics of industrial industry, the wastewater generated in the production process usually also contains sulfides, mainly including hydrogen sulfide and other substances. Hydrogen sulfide is highly toxic, and the increase of sulfur compound content will reduce the activity of anaerobic microorganisms in wastewater, which will limit the effect of anaerobic treatment. In addition, hydrogen sulfide has strong killing ability to aquatic organisms, which can easily cause corrosion to equipment and pipelines, and at the same time affect the quality of groundwater, and even harm human health.

[0003] Physical and chemical method is a commonly used desulfurization method, which adds chemical reagent or catalyst in the treatment process, and separates and treats under certain conditions (such as high temperature and high pressure or oxygen is introduced, etc.). At present, the common treatment methods of sulfur-containing wastewater are as follows: gas stripping method, acidification absorption method, air oxidation method, chemical flocculation method, electrochemical method, etc. However, the above several physical and chemical desulfurization methods have problems such as high energy consumption, complex operation, low recovery efficiency of sulfur single element and secondary pollution. SUMMARY

[0004] In view of the problems, the present application is proposed to provide an anaerobic coupling electric stimulation and desulfurization of bacteria and algae wastewater treatment system and method to overcome the problems or at least partially solve the problems, which comprises:

[0005] An anaerobic coupling electric stimulation and desulfurization of bacteria and algae wastewater treatment system comprises a primary anaerobic reactor and a secondary anaerobic reactor connected in sequence;

[0006] The primary anaerobic reactor comprises an anaerobic fluid state zone and a desulfurization reaction zone, the anaerobic fluid state zone is filled with filler carrier, the anaerobic fluid state zone is used for converting sulfate in wastewater into sulfide by sulfate-reducing bacteria attached to the filler carrier, the desulfurization reaction zone is filled with microalgae and desulfurization bacteria, the desulfurization reaction zone is used for converting sulfide in wastewater into sulfur single element by using oxygen produced by photosynthesis of the microalgae by the desulfurization bacteria, the water outlet of the desulfurization reaction zone is connected with the secondary anaerobic reactor, and the secondary anaerobic reactor is used for converting organic matter in wastewater into methane.

[0007] Further, a pretreatment tank group is further included, the water outlet of the pretreatment tank group is connected with the primary anaerobic reactor, and the pretreatment tank group comprises an oil separation tank, an adjusting tank, a flotation tank and a hydrolysis acidification tank connected in sequence;

[0008] The oil separation tank is used for removing the floatable oil substances in the wastewater, the adjusting tank is used for optimizing the wastewater quality and adjusting the wastewater effluent water quantity, and the air flotation tank is used for removing the light oil substances and suspended substances in the wastewater.

[0009] Further, the post-treatment tank group is connected with the effluent end of the secondary anaerobic reactor, and comprises an anoxic tank, an aerobic tank and a secondary sedimentation tank connected in sequence.

[0010] The aerobic tank is connected with the anoxic tank through a nitrification liquid reflux pipeline, and a sludge reflux device is arranged between the secondary sedimentation tank, the hydrolysis acidification tank and the primary anaerobic reactor.

[0011] Further, the anaerobic fluidized zone is arranged at the bottom of the desulfurization reaction zone, and comprises a water inlet, a water distribution plate and a gas hole plate.

[0012] Further, the desulfurization reaction zone comprises electrodes, light sources, a sulfur recovery baffle weir and a water outlet.

[0013] Further, an inner reflux pipeline is arranged in the primary anaerobic reactor, and the inner reflux pipeline is connected with a circulating pump.

[0014] Further, the filler carrier is one or two of quartz sand, activated carbon and zeolite porous material, the particle size of the filler carrier ranges from 0.2 mm to 1.0 mm, and the filling volume of the filler carrier accounts for 10-30% of the total volume of the reactor.

[0015] Further, the microalgae include one or more of Chlorella, Scenedesmus, Oedogonium, Chlamydomonas and Euglena.

[0016] Further, the nitrification liquid reflux pipeline is provided with a flow control device for adjusting the volume of the nitrification liquid refluxed to the anoxic tank.

[0017] A wastewater treatment method based on the above wastewater treatment system, comprising the steps of:

[0018] The pretreated wastewater is sent to the water inlet of the anaerobic fluidized zone of the first-stage anaerobic reactor, and the treated wastewater is obtained at the water outlet of the anaerobic fluidized zone; wherein the anaerobic fluidized zone treats the pretreated wastewater, so that the sulfate in the wastewater is reduced to sulfide by the sulfate-reducing bacteria attached to the filler carrier in the anaerobic fluidized zone;

[0019] The wastewater treated by the anaerobic fluidized zone is sent to the desulfurization reaction zone of the first-stage anaerobic reactor, and the treated wastewater is obtained at the water outlet of the desulfurization reaction zone; wherein the desulfurization reaction zone treats the wastewater treated by the anaerobic fluidized zone, so that the sulfide in the wastewater is converted into elemental sulfur;

[0020] The wastewater treated by the desulfurization reaction zone is sent to the second-stage anaerobic reactor, and the treated wastewater is obtained at the water outlet of the second-stage anaerobic reactor; wherein the second-stage anaerobic reactor treats the wastewater treated by the desulfurization reaction zone, so that the organic matter in the wastewater is converted into methane.

[0021] The present application has the following advantages:

[0022] In the embodiments of the present application, compared with the existing sulfur removal process in the prior art, which has problems such as high operating energy consumption, complex operation, low elemental sulfur recovery efficiency, and secondary pollution, the present application provides a two-stage anaerobic-microalgae-electric stimulation synergistic desulfurization solution, specifically: comprising a first-stage anaerobic reactor and a second-stage anaerobic reactor connected in sequence; the first-stage anaerobic reactor comprises an anaerobic fluidized zone and a desulfurization reaction zone, the anaerobic fluidized zone is filled with a filler carrier, the anaerobic fluidized zone is used to convert the sulfate in the wastewater into sulfide by the sulfate-reducing bacteria attached to the filler carrier, the desulfurization reaction zone is filled with microalgae and desulfurization bacteria, the desulfurization reaction zone is used to convert the sulfide in the wastewater into elemental sulfur by the oxygen produced by the photosynthesis of the microalgae, which is utilized by the desulfurization bacteria, the water outlet of the desulfurization reaction zone is connected with the second-stage anaerobic reactor, and the second-stage anaerobic reactor is used to convert the organic matter in the wastewater into methane. By using the first-stage anaerobic reactor as a desulfurization reaction process, the wastewater is first subjected to desulfurization recovery, thereby avoiding the inhibitory effect of sulfur-containing compounds on the anaerobic microorganisms in the downstream reactor, and the wastewater is then subjected to degradation of organic matter pollutants in the second-stage anaerobic reactor, thereby simultaneously recovering methane energy substances and improving the biodegradability of the wastewater. Compared with the traditional wastewater desulfurization treatment method, the anaerobic-microalgae-electric stimulation coupled process is a biological efficient desulfurization process that can realize low energy consumption, no secondary pollution, high sulfur recovery rate, and simultaneous optimization of wastewater quality, the valuable nutrients in the water body are reused by the bacteria and algae, thereby effectively reducing water pollution, realizing mutual cooperation and mutual benefit of the bacteria and algae symbiotic system, and long-term stable operation, and the desulfurization treatment process is more low-carbon and sustainable. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the present application, the drawings needed to be used in the description of the present application will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and all other drawings obtained by those skilled in the art without any creative labor on the basis of these drawings also belong to the protection scope of the present application.

[0024] Figure 1 is a schematic diagram of a wastewater treatment system provided by an embodiment of the present application, which is an anaerobic coupling electric stimulation and bacteria-algae desulfurization system;

[0025] Figure 2 is a structural schematic diagram of a primary anaerobic reactor provided by an embodiment of the present application;

[0026] Figure 3 is a step flow chart of a wastewater treatment method provided by an embodiment of the present application, which is an anaerobic coupling electric stimulation and bacteria-algae desulfurization method.

[0027] In the figure: 1, water inlet; 2, water distribution plate; 3, filler carrier; 4, air hole plate; 5, circulating pump; 6, desulfurization reaction zone filler; 7, electrode; 8, light source; 9, sulfur recovery baffle weir; 10, water outlet. DETAILED DESCRIPTION

[0028] In order to make the purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below in combination with the drawings and specific embodiments. Obviously, the described embodiments are some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative labor also belong to the protection scope of the present application.

[0029] The inventors find through analyzing the prior art that, compared with the physical and chemical method, the biological treatment method does not need to add chemical agents or catalysts, and the treatment process is carried out at normal temperature and pressure, and the obtained elemental sulfur product can be recycled. In nature, microalgae have high oxygen production capacity driven by light, and microalgae have strong tolerance to toxicity in wastewater, so they still have strong adaptability and growth activity in seriously polluted water bodies. The wastewater treatment based on microalgae has low energy demand, and is an economic and sustainable wastewater treatment method. Microalgae can reduce carbon dioxide emissions in water bodies, use trace elements in water bodies to maintain normal growth and reproduction, remove nitrogen and phosphorus components in wastewater and convert them into valuable biomass, remove different toxic substances through biosorption, bioaccumulation and biodegradation processes, and reduce the degree of pollution of water bodies. Due to the high conductivity of industrial wastewater, it becomes a good electrolyte for electrochemical reaction. Studies have shown that an external electric field can increase the intracellular protein content of bacteria, enhance the activity of cell ATPase, and promote microbial growth and metabolism, so the activity of microorganisms can be improved by controlling the intensity of direct current through regulating voltage.

[0030] With reference to Figure 1 and Figure 2 , an embodiment provided by the present application shows an anaerobic coupling electric stimulation synergistic bacteria-algae desulfurization wastewater treatment system, which comprises a primary anaerobic reactor and a secondary anaerobic reactor connected in sequence.

[0031] The primary anaerobic reactor comprises an anaerobic fluidized state zone and a desulfurization reaction zone, the anaerobic fluidized state zone is filled with a filler carrier 3, the anaerobic fluidized state zone is used for converting sulfate in wastewater into sulfide by sulfate-reducing bacteria attached to the filler carrier 3, the desulfurization reaction zone is filled with microalgae and desulfurization bacteria 6, the desulfurization reaction zone is used for producing oxygen by photosynthesis of the microalgae, the oxygen is used by the desulfurization bacteria while converting sulfide in wastewater into elemental sulfur, the effluent outlet of the desulfurization reaction zone is connected with the secondary anaerobic reactor, and the secondary anaerobic reactor is used for converting organic matter in wastewater into methane.

[0032] In the embodiments of the present application, in order to solve the problems of high energy consumption, complex operation, low recovery efficiency of elemental sulfur and secondary pollution in the prior art, a two-stage anaerobic-microalgae-electric stimulation synergistic desulfurization solution is provided, specifically: comprising a first-stage anaerobic reactor and a second-stage anaerobic reactor connected in sequence; the first-stage anaerobic reactor comprises an anaerobic fluidized state zone and a desulfurization reaction zone, the anaerobic fluidized state zone is filled with a filler carrier 3, the anaerobic fluidized state zone is used for converting sulfate in wastewater into sulfide by sulfate-reducing bacteria attached to the filler carrier 3, the desulfurization reaction zone is filled with microalgae and desulfurization bacteria, the desulfurization reaction zone is used for producing oxygen by photosynthesis of the microalgae, the oxygen is used by the desulfurization bacteria while converting sulfide in wastewater into elemental sulfur, and the effluent outlet of the desulfurization reaction zone is connected with the second-stage anaerobic reactor, and the second-stage anaerobic reactor is used for converting organic matter in wastewater into methane. By using the first-stage anaerobic reactor as a desulfurization reaction process, wastewater is first recovered by desulfurization, so as to avoid the inhibitory effect of sulfur-containing compounds on anaerobic microorganisms in the downstream reactor, and then the wastewater enters the second-stage anaerobic reactor to degrade organic pollutant, thereby synchronously recovering methane energy substance and improving the biodegradability of wastewater. Compared with the traditional wastewater desulfurization treatment method, the anaerobic-microalgae-electric stimulation coupled process is a biological efficient desulfurization process capable of realizing low energy consumption, no secondary pollution, high sulfur recovery rate and simultaneous optimization of wastewater quality, the valuable nutrients in water are reused by bacteria and algae, the water pollution is effectively reduced, the mutualism and long-term stable operation of the bacteria-algae symbiotic system are realized, and the desulfurization treatment process is more low-carbon and sustainable.

[0033] In the following, a wastewater treatment system for anaerobic coupling electric stimulation synergistic bacteria-algae desulfurization in the present exemplary embodiment will be further described.

[0034] It should be noted that the anaerobic fluidized bed (AFB) reactor adopted in the present application combines the advantages of biological fluidized bed technology and contact oxidation method technology, the anaerobic microorganisms are attached and grown in the form of biofilm on the filler carrier with small particle size and large specific surface area, the filler carrier in the reactor presents a high-speed fluidized state under a high upward flow rate, the contact area between the microorganisms and the wastewater pollutant medium is increased, the mass transfer rate is improved, and the resistance to organic load and toxic load is improved.

[0035] Firstly, the wastewater is divided into different zones by the structure inside the first-stage anaerobic fluidized bed, and the sulfate is first converted into sulfide by the action of sulfate-reducing bacteria in the anaerobic fluidized zone; the desulfurization reaction zone is filled with fillers, and the fillers 6 in the desulfurization reaction zone are microalgae and desulfurization bacteria, then the microalgae use photosynthesis to fix carbon dioxide in the anaerobic system water to produce oxygen, creating a micro-oxygen environment in the desulfurization reaction zone, and the oxygen produced supplies the sulfur bacteria to oxidize the sulfide into elemental sulfur. The internal fluidization state of the anaerobic fluidized bed is driven by the external circulation of the hydraulic reactor to improve the conversion efficiency of elemental sulfur. The wastewater is subjected to efficient desulfurization in the anaerobic fluidized bed reactor, and part of the refractory organic matter is degraded into easily biodegradable organic matter, improving the biodegradability of the water quality; the first-stage anaerobic effluent enters the second-stage anaerobic reactor to further remove the organic matter in the wastewater and recover the energy substance methane gas. The combination of the two-stage anaerobic reactors can efficiently recover the high-purity sulfur resource and methane energy substance from the wastewater in stages, while avoiding the inhibition of the organic matter degradation process in the anaerobic system by high-concentration sulfate and sulfide, optimizing the wastewater quality, and providing good water quality conditions for the subsequent biochemical process.

[0036] In a specific implementation, the second-stage anaerobic reactor is a UASB reactor, which is an abbreviation of upflow anaerobic sludge bed reactor. It is an anaerobic biological method for treating wastewater, and the main part of the UASB reactor is mainly divided into two regions, namely the reaction zone and the three-phase separation zone. The reaction zone is the main body of the UASB reactor, and the reactor has the following outstanding features: it can cultivate granular sludge with good settling performance, form a sludge bed with extremely high sludge concentration, and has a series of excellent operating characteristics such as high volumetric loading, good sludge retention effect, and compact reactor structure. The wastewater of the present embodiment is subjected to desulfurization treatment by the first-stage anaerobic reactor and then enters the UASB reactor, which is used as the methane-producing phase of the wastewater. A small amount of sulfate remains in the wastewater to maintain a high C / S ratio, which is beneficial to the stable operation of the UASB reactor, and the organic matter in the wastewater is converted into recoverable energy substance methane.

[0037] In a specific implementation, the main components of the desulfurization bacteria in the desulfurization reaction zone include colorless sulfur bacteria, especially denitrobacterium.

[0038] In the present embodiment, a pretreatment pool group is further included, the effluent end of the pretreatment pool group is connected with the first-stage anaerobic reactor, and the pretreatment pool group includes an oil separation tank, an adjusting tank, a flotation tank and a hydrolysis acidification tank connected in sequence.

[0039] The oil separation tank is used to remove the floatable oil substances in the wastewater, the adjusting tank is used to optimize the wastewater quality and adjust the wastewater effluent volume, the flotation tank is used to remove the light oil substances and suspended solids in the wastewater, and the hydrolysis acidification tank is used to hydrolyze the suspended organic matter and macromolecular substances in the wastewater into small molecular organic matter.

[0040] It should be noted that the water quality of the high-concentration sulfur-containing organic wastewater raw water in the embodiment is as follows: pH = 7-8, COD concentration 5000-8000 mg / L, sulfate concentration 800-1100 mg / L, ammonia nitrogen 300-500 mg / L. The wastewater passes through an oil separation tank to remove floatable oil substances, a regulating tank to optimize the wastewater quality and adjust the wastewater effluent flow, and then passes through a gas floatation tank to remove light oil substances and suspended solids.

[0041] The wastewater passes through the pretreatment process into the hydrolysis acidification tank, and the suspended organic matter and macromolecular substances (carbohydrate, lipid, etc.) are hydrolyzed into small molecular organic matter by microbial extracellular enzymes, so as to improve the B / C ratio, and the residence time of the reaction tank is 7-10 h.

[0042] In the embodiment, a post-treatment tank group is further included, a water inlet end of the post-treatment tank group is connected with a water outlet end of the secondary anaerobic reactor, and the post-treatment tank group includes an anoxic tank, an aerobic tank and a secondary sedimentation tank connected in sequence.

[0043] The aerobic tank is connected with the anoxic tank through a nitrification liquid reflux pipeline, and a sludge reflux device is arranged between the secondary sedimentation tank, the hydrolysis acidification tank and the primary anaerobic reactor.

[0044] It should be noted that after the wastewater passes through the anaerobic treatment of the two-stage anaerobic reactor, the wastewater flows into the anoxic tank and the aerobic tank in sequence to perform the denitrification and phosphorus removal process. The aerobic tank is connected with the anoxic tank through a nitrification liquid reflux pipeline, and a sludge reflux device is arranged between the secondary sedimentation tank and the hydrolysis acidification tank and the anaerobic fluidized bed reactor.

[0045] As an example, the volume ratio of the nitrification liquid of the aerobic tank flowing into the anoxic tank is 50%-100%.

[0046] It should be noted that after the wastewater flows through the secondary sedimentation tank, the wastewater is discharged, part of the sludge of the secondary sedimentation tank is refluxed to the hydrolysis acidification tank for anaerobic digestion to reduce the sludge treatment load, and part of the remaining sludge is refluxed to the anaerobic biological fluidized bed reactor to maintain the microbial concentration in the reactor.

[0047] As an example, the sludge reflux ratios of the secondary sedimentation tank effluent refluxing to the hydrolysis acidification tank and the anaerobic fluidized bed are respectively 20-100%.

[0048] In a specific implementation, the nitrification liquid reflux pipeline is provided with a flow control device, and the flow control device is used to adjust the volume of the nitrification liquid refluxing to the anoxic tank.

[0049] In the embodiment, reference is made to Figure 2The anaerobic fluidized zone is located at the bottom of the desulfurization reaction zone. The anaerobic fluidized zone includes an inlet 1, a water distribution plate 2, and an air vent plate 4. The inlet 1 is located at the bottom of the anaerobic fluidized zone, the water distribution plate 2 is located on the side of the inlet 1, and the air vent plate 4 is located between the anaerobic fluidized zone and the desulfurization reaction zone.

[0050] It should be noted that the primary anaerobic reactor is an integrated device for sulfate reduction and elemental sulfur recovery. Wastewater enters the primary anaerobic reactor through inlet 1 at the bottom. The primary anaerobic reactor is equipped with functional reaction zones, the lower layer of which is an anaerobic fluidized zone. The reactor is equipped with packing material 3, whose main function is to perform primary anaerobic treatment of organic pollutants in the wastewater, and to convert sulfate in the water into sulfides by utilizing the growth and metabolism of sulfate-reducing bacteria.

[0051] In this embodiment, refer to Figure 2 The desulfurization reaction zone includes an electrode 7, a light source 8, a sulfur recovery baffle 9, and a water outlet 10. The electrode 7 is electrically connected to the light source 8, and the light source 8 is located in a glass sleeve between the electrodes 7. The sulfur recovery baffle 9 is located at the top of the desulfurization reaction zone, and the water outlet 10 is located on the side of the sulfur recovery baffle 9.

[0052] It should be noted that the external circulating hydraulic flow of the anaerobic fluidized bed allows the water in the fluidized zone to enter the upper desulfurization reaction zone through the pore plates inside the reactor. The carbon dioxide and some nutrients produced during the anaerobic reaction are used by microalgae to generate oxygen through photosynthesis. This oxygen is rapidly acquired and utilized by the desulfurization bacteria, which convert the sulfides in the wastewater into high-valence sulfur. Through electrical stimulation by electrodes and light sources, the growth activity of sulfur bacteria and microalgae is promoted. A sulfur recovery baffle is installed at the top of the primary anaerobic reactor. The hydraulic action causes the generated sulfur particles to settle and float to the surface, accumulating on the sulfur recovery baffle 9 for recovery. At the same time, the serrated baffle plate prevents the loss of bacteria and algae.

[0053] As an example, the electrode 7 is made of porous carbon-based materials such as carbon felt or stainless steel, and the cathode potential is maintained between -0.6 and -0.2V by adjusting the voltage.

[0054] As an example, the light source 8 for microalgae is a multi-row dense LED tube, and the light source 8 is placed in a glass sleeve between the electrodes, with the light intensity set to 1000-5000 Lx; the top of the desulfurization reaction zone is made of transparent corrosion-resistant polymethyl methacrylate (PMMA) plate, and the outer wall of the reactor has an aluminum graphene film coating, which is conducive to the reflection of light from the light source and improves the light reflectivity.

[0055] In the embodiment, the primary anaerobic reactor is provided with an internal reflux pipeline connected with the circulating pump 5, and the terminal joint of the internal reflux pipeline is connected with the pipeline of the water inlet 1.

[0056] As an example, the internal reflux pipeline is arranged at the middle position of the primary anaerobic reactor, and the terminal joint of the reflux pipeline is connected with the water inlet pipeline of the anaerobic fluidized bed.

[0057] In the embodiment, the filler carrier 3 is one or two of quartz sand, activated carbon and zeolite porous material, the particle size of the filler carrier 3 ranges from 0.2 to 1.0 mm, and the filling volume of the filler carrier 3 accounts for 10-30% of the total volume of the reactor.

[0058] In the embodiment, the microalgae include one or more of Chlorella, Scenedesmus, Ankistrodesmus, Chlamydomonas and Euglena.

[0059] Referring to Figure 3 , a wastewater treatment method of anaerobic coupling electric stimulation and synergistic bacteria-algae desulfurization is shown,

[0060] The method comprises:

[0061] S310, the pretreated wastewater is sent to the water inlet of the anaerobic fluidized zone of the primary anaerobic reactor, and the treated wastewater is obtained at the water outlet of the anaerobic fluidized zone; wherein the anaerobic fluidized zone treats the pretreated wastewater, so that the sulfate in the wastewater is reduced to sulfide by the sulfate-reducing bacteria attached to the filler carrier in the anaerobic fluidized zone;

[0062] S320, the wastewater treated by the anaerobic fluidized zone is sent to the desulfurization reaction zone of the primary anaerobic reactor, and the treated wastewater is obtained at the water outlet of the desulfurization reaction zone; wherein the desulfurization reaction zone treats the wastewater treated by the anaerobic fluidized zone, so that the sulfide in the wastewater is converted into elemental sulfur;

[0063] S330, the wastewater treated by the desulfurization reaction zone is sent to the secondary anaerobic reactor, and the treated wastewater is obtained at the water outlet of the secondary anaerobic reactor; wherein the secondary anaerobic reactor treats the wastewater treated by the desulfurization reaction zone, so that the organic matter in the wastewater is converted into methane.

[0064] As described in step S310, the pretreated wastewater is sent to the water inlet of the anaerobic fluidized zone of the primary anaerobic reactor, and the treated wastewater is obtained at the water outlet of the anaerobic fluidized zone; wherein the anaerobic fluidized zone treats the pretreated wastewater, so that the sulfate in the wastewater is reduced to sulfide by the sulfate-reducing bacteria attached to the filler carrier in the anaerobic fluidized zone.

[0065] Specifically, the wastewater is sent to the anaerobic fluidized zone of the first-stage anaerobic reactor through a pretreatment process from an inlet, and a distributor uniformly distributes the wastewater to the entire treatment area, so that the wastewater is in full contact with the filler carriers in the anaerobic fluidized zone, thereby improving the treatment efficiency. In the anaerobic fluidized zone, the sulfate is reduced to sulfide by sulfate-reducing bacteria.

[0066] As described in step S320, the wastewater treated in the anaerobic fluidized zone is sent to the desulfurization reaction zone of the first-stage anaerobic reactor, and the treated wastewater is obtained at the outlet of the desulfurization reaction zone. The desulfurization reaction zone treats the wastewater treated in the anaerobic fluidized zone, so that the sulfide in the wastewater is converted into elemental sulfur.

[0067] Specifically, the effluent of the anaerobic fluidized zone enters the desulfurization reaction zone by hydraulic action. Since the microalgae produce oxygen by photosynthesis, the desulfurization bacteria use the sulfide as an electron donor and the nitrate and nitrite as electron acceptors to perform denitrification and sulfide oxidation in a micro-oxygen environment. The sulfide-type denitrification reaction process with nitrate as an electron acceptor is as follows, which realizes efficient accumulation of elemental sulfur. The optimal sulfur-nitrogen ratio is 5:2-5:3. The desulfurization reactor is provided with an electrode device, which is used to stimulate the growth activity of bacteria and algae and improve the conversion efficiency of elemental sulfur.

[0068]

[0069] As described in step S330, the wastewater treated in the desulfurization reaction zone is sent to the second-stage anaerobic reactor, and the treated wastewater is obtained at the outlet of the second-stage anaerobic reactor. The second-stage anaerobic reactor treats the wastewater treated in the desulfurization reaction zone, so that the organic matter in the wastewater is converted into methane.

[0070] Specifically, the effluent of the desulfurization reaction zone enters the second-stage anaerobic reactor. The wastewater passes through the sludge layer formed by bacteria, and under the adsorption, entrapment, bioflocculation and biodegradation of the sludge layer, the long-chain macromolecular organic matter is broken into short-chain small-molecule organic matter, the insoluble organic matter is hydrolyzed into soluble organic matter, and the difficultly biodegradable macromolecular pollutants are degraded into small-molecule organic matter that is easy to biodegrade, thereby improving the biodegradability of the wastewater and improving the subsequent process treatment conditions.

[0071] Although the preferred embodiments of the present application have been described, those skilled in the art can make additional changes and modifications to the embodiments once they know the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including all the preferred embodiments and all the changes and modifications falling within the scope of the present application.

[0072] Finally, it is to be understood that the phraseology or terminology such as "first" and "second" etc. used herein is merely intended to differentiate one entity or operation from another entity or operation, without necessarily requiring or implying any actual such relationship or order between such entities or operations. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the recited element.

[0073] The above has carried on the detailed introduction to the wastewater treatment system and method of anaerobic coupling electric stimulation synergistic bacteria-algae desulfurization provided by the present application, the principle and implementation mode of the present application are described in this paper by applying specific examples, the above example is only used to help understand the method and core idea of the present application; at the same time, for the general technical personnel in the art, according to the idea of the present application, the specific implementation mode and application range will be changed, according to the above, the content of the specification should not be understood as the limitation of the present application.

Claims

1. A wastewater treatment system for anaerobic coupled electric stimulation synergized with bacteria-algal desulfurization, characterized in that, The first-stage anaerobic reactor and the second-stage anaerobic reactor are connected in sequence. The first-stage anaerobic reactor comprises an anaerobic fluidized zone and a desulfurization reaction zone, the anaerobic fluidized zone is filled with filler carriers, the anaerobic fluidized zone is used for converting sulfate in wastewater into sulfide by sulfate-reducing bacteria attached to the filler carriers, the desulfurization reaction zone is filled with microalgae and desulfurization bacteria, the desulfurization reaction zone is used for converting sulfide in wastewater into elemental sulfur by photosynthesis of the microalgae, oxygen is produced and utilized by the desulfurization bacteria at the same time, the water outlet of the desulfurization reaction zone is connected with the second-stage anaerobic reactor, and the second-stage anaerobic reactor is used for converting organic matter in wastewater into methane. The anaerobic fluidized zone is arranged at the bottom of the desulfurization reaction zone, the anaerobic fluidized zone comprises a water inlet, a water distribution plate and a gas hole plate, the water inlet is arranged at the bottom of the anaerobic fluidized zone, the water distribution plate is arranged at the side of the water inlet, and the gas hole plate is located between the anaerobic fluidized zone and the desulfurization reaction zone. The desulfurization reaction zone comprises electrodes, light sources, a sulfur recovery baffle weir and a water outlet, the electrodes are electrically connected with the light sources, the light sources are arranged in glass sleeves between the electrodes, the sulfur recovery baffle weir is arranged at the top of the desulfurization reaction zone, and the water outlet is arranged at the side of the sulfur recovery baffle weir. An internal reflux pipeline is arranged in the first-stage anaerobic reactor, the internal reflux pipeline is connected with a circulating pump, and a terminal connector of the internal reflux pipeline is connected with a pipeline of the water inlet.

2. The wastewater treatment system of claim 1, wherein, A pretreatment pool group is further arranged, a water outlet end of the pretreatment pool group is connected with the first-stage anaerobic reactor, and the pretreatment pool group comprises an oil separation pool, a regulating pool, a flotation pool and a hydrolysis acidification pool connected in sequence. The oil separation pool is used for removing floatable oil substances in wastewater, the regulating pool is used for optimizing wastewater quality and adjusting wastewater water volume, the flotation pool is used for removing light oil substances and suspended matters in wastewater, and the hydrolysis acidification pool is used for hydrolyzing suspended organic matters and macromolecular substances in wastewater into small-molecule organic matters.

3. The wastewater treatment system of claim 2, wherein, A post-treatment pool group is further arranged, a water inlet end of the post-treatment pool group is connected with a water outlet end of the second-stage anaerobic reactor, and the post-treatment pool group comprises an anoxic pool, an aerobic pool and a secondary sedimentation pool connected in sequence. The aerobic pool is connected with the anoxic pool through a nitrification liquid reflux pipeline, and a sludge reflux device is arranged between the secondary sedimentation pool, the hydrolysis acidification pool and the first-stage anaerobic reactor.

4. The wastewater treatment system of claim 1, wherein, The filler carriers are one or two of quartz sand, activated carbon and zeolite porous material, the particle size of the filler carriers ranges from 0.2 mm to 1.0 mm, and the filling volume of the filler carriers accounts for 10% to 30% of the total volume of the reactor.

5. The wastewater treatment system of claim 1, wherein, The microalgae comprise one or several of chlorella, scenedesmus, microspora, chlamydomonas and euglena.

6. The wastewater treatment system of claim 3, wherein, The nitrification liquid reflux pipeline is provided with a flow control device, and the flow control device is used for adjusting the volume of the nitrification liquid refluxed to the anoxic pool.

7. A method of wastewater treatment based on the wastewater treatment system according to any one of claims 1 to 6, characterized in that, The method comprises the following steps: The pretreated wastewater is sent to the water inlet of the anaerobic fluidized zone of the first-stage anaerobic reactor, and the treated wastewater is obtained at the water outlet of the anaerobic fluidized zone; wherein the anaerobic fluidized zone treats the pretreated wastewater, so that the sulfate in the wastewater is reduced to sulfide by the sulfate-reducing bacteria attached to the filler carriers in the anaerobic fluidized zone; The wastewater treated by the anaerobic fluidized zone is sent to the desulfurization reaction zone of the first-stage anaerobic reactor, and the treated wastewater is obtained at the water outlet of the desulfurization reaction zone; wherein the desulfurization reaction zone treats the wastewater treated by the anaerobic fluidized zone, so that the sulfide in the wastewater is converted into elemental sulfur; The wastewater treated by the desulfurization reaction zone is sent to the second-stage anaerobic reactor, and the treated wastewater is obtained at the water outlet of the second-stage anaerobic reactor; wherein the second-stage anaerobic reactor treats the wastewater treated by the desulfurization reaction zone, so that the organic matter in the wastewater is converted into methane.

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