CN108821429B - Sulfate wastewater treatment device system and treatment method thereof - Google Patents

Sulfate wastewater treatment device system and treatment method thereof Download PDF

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CN108821429B
CN108821429B CN201810601575.7A CN201810601575A CN108821429B CN 108821429 B CN108821429 B CN 108821429B CN 201810601575 A CN201810601575 A CN 201810601575A CN 108821429 B CN108821429 B CN 108821429B
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穆廷桢
邢建民
苗得露
杨茂华
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Institute of Process Engineering of CAS
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    • C02F3/34—Biological treatment of water, waste water, or sewage characterised by the microorganisms used
    • C02F3/345—Biological treatment of water, waste water, or sewage characterised by the microorganisms used for biological oxidation or reduction of sulfur compounds
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Abstract

The invention provides a device system for treating sulfate wastewater and a treatment method thereof. The treatment system comprises an anaerobic reaction unit, a stripping unit, an absorption unit, a biological desulfurization unit and a gas storage unit. The treatment method provided by the invention comprises the following steps of 1) carrying out anaerobic desulfurization on sulfate wastewater to obtain methane containing hydrogen sulfide and anaerobic reaction liquid; 2) carrying out air stripping on the anaerobic reaction liquid to obtain air stripping gas containing hydrogen sulfide and air stripping wastewater; 3) absorbing methane containing hydrogen sulfide and stripping gas containing hydrogen sulfide to obtain sulfide absorption liquid and purified gas; 4) carrying out biological sulfur oxidation on the sulfide absorption liquid under an aeration condition to obtain elemental sulfur and clear liquid; 5) the purified gas is stored and recycled back to the stripping step as stripping gas. The system and the method provided by the invention realize efficient, green and harmless and resource treatment of the acidic high-sulfate-content wastewater, and obviously improve the process economy.

Description

Sulfate wastewater treatment device system and treatment method thereof
Technical Field
The invention belongs to the field of environmental engineering, and relates to a device system for treating sulfate wastewater and a treatment method thereof.
Background
Sulfuric acid and sulfurous acid are important chemical raw materials, and with the continuous development of industry, a large amount of Salt (SO) containing high-concentration sulfuric acid is discharged in the production process in the fields of chemical industry, monosodium glutamate, pharmacy, molasses alcohol, tanning, paper making and the like4 2-) The organic wastewater of (2). The discharge amount of pollutants in the paper industry is second to that of the Chemical industry, the discharge amount of wastewater is 31.8 hundred million tons, which accounts for 16.1 percent of the national industrial wastewater discharge amount, and the discharge amount of COD (Chemical Oxygen Demand, which is one of the comprehensive indexes of relative content of organic matters) is 148.8 million tons, which accounts for 33 percent of the national COD discharge amount. By acid sulfitationThe pulping waste water has a pH value of 1.2-2.0, a COD of 500-2000 mg/L, and SO4 2-And SO3 2-The total concentration is 1000-3000 mg/L. Typical antibiotic wastewater generally has a sulfate content of more than 2000mg/L, and some of the wastewater has even up to 15000 mg/L. Although the sulfate is harmless, the sulfate meets the anaerobic environment and generates hydrogen sulfide (H) under the action of Sulfate Reducing Bacteria (SRB)2S)，H2S can severely corrode treatment facilities and drainage pipelines, and in addition, H2S has bad smell, and the concentration of S can cause human nerve poisoning when reaching a certain value, and can react with ozone in the atmosphere to generate sulfuric acid, which is one of the causes of acid rain. When the sulfate wastewater is discharged into a water body, the receiving water body is acidified, the pH value is reduced, aquatic organisms are damaged, and when the sulfate wastewater is discharged into a farmland, the soil structure is damaged, so that the soil is hardened, the crop yield is reduced, and the quality of agricultural products is reduced. Most sulfates are very soluble and stable in nature and are therefore difficult to remove by natural purification. Therefore, finding a stable, efficient, economical and practical treatment method for sulfate-containing wastewater has become a focus of research in various countries. At present, the biological anaerobic digestion process is the main method for treating organic wastewater. Compared with a physical and chemical method, the biological anaerobic digestion process has the characteristics of good treatment effect, low maintenance and operation cost, no secondary pollution and the like. After anaerobic digestion, COD is converted into clean energy biogas, and the generated sludge is high-quality organic fertilizer.
When the high-concentration sulfate organic wastewater is treated by adopting an anaerobic method, the anaerobic degradation process is inhibited and even the system is collapsed due to the intervention of sulfate reduction reaction, and the main reasons are that the problems of matrix competition of Methanogens (MPB) and Sulfate Reducing Bacteria (SRB) and toxicity inhibition of sulfate reducing products (sulfide) on the MPB and the SRB exist in the system at the same time. Wherein the reduction product HS of the sulfate-，S2-And metal sulfides, etc., are inhibitors of bacterial growth, microorganisms, especially MPB, are highly susceptible to inhibition by these reduction products, MPB is S-tolerant2-The concentration was 25mg/L and the toxicity of the sulfide increased with decreasing pH. Free H in these inhibitors2S has the greatest toxic effectThe reason may be H2S is neutral, and only neutral can pass through the cell membrane of the thallus with negative electricity to destroy the protein. The sulfide is found to be far more toxic than other compound sulfur, and insoluble sulfide generally has no inhibition effect on anaerobic process. The inhibitory effect on microorganisms in sulfides is mainly soluble H2And S. Sulfate is indispensable as an electron acceptor in the metabolic process of SRB growth. There is also competition for sulfate between the different types of SRB, which is particularly pronounced at lower sulfate concentrations. Water inlet SO in a certain range4 2-Concentration and S in effluent2-SO that there is a linear relationship between the concentrations of SO and water4 2-The concentration plays a crucial role in the proper operation of the reactor. S2-The accumulation of (b) also inhibits acid-producing bacteria and sulfate-reducing bacteria, affecting the sulfate removal effect.
The sulfur is an important chemical raw material, the global natural sulfur yield is low, China hardly has natural sulfur ores, most of the sulfur is recovered from sulfides generated in the petroleum and natural gas processing process, and the recovered sulfur yield accounts for over 96 percent of the world sulfur yield. Biological desulfurization refers to a process of oxidizing hydrogen sulfide in biogas into elemental sulfur by sulfur oxidizing bacteria at normal temperature and normal pressure and removing the elemental sulfur from a system, and is a desulfurization technology developed in the last 90 years. Compared with the traditional physical and chemical methods, the biological desulfurization technology has the advantages of mild conditions, no secondary pollution, simple equipment and the like. In addition, the produced biological sulfur particles are nano-scale, have good biocompatibility and hydrophilicity, and are the best raw materials for producing medicines and pesticides. There are over 100 commercial Shell-Paques biological desulfurization units worldwide, with over 14 units being used in the natural gas field. With the gradual development of human society and the continuous improvement of the environmental requirements of people, the microbial desulfurization is used as a new method for treating H in natural gas and methane2The S method has obvious advantages, so that the S method has wide development space and application prospect in the future. The sulfur oxidizing bacteria adopted at present are mainly thiobacillus, the optimum pH value is about 8.0, and the tolerance salinity is only 0.5-2.5%.
Halophiles are a class of extreme environmental microorganisms that normally grow in solutions of high salt concentration and high pH, and when salinity or pH is too low, this growth is inhibited, thus being a class of two-factor extreme microorganisms. The extreme microorganisms live in various extreme environments for a long time, and form a unique physiological mechanism. In general, alkalophilic microorganisms exist Na+/H+Reverse transport system, the respiratory chain of cells secretes H+The cells are in alkaline state, and Na is converted by the cells under the action of the system+Discharging from the body while allowing H to stand+Enter cells, ensure the acid-base balance in the cells and ensure that various life activities in the cells can be normally carried out. The traditional gas biological desulphurization process has the problems of low alkalinity of absorption liquid, large circulation amount and high energy consumption.
CN102351381A discloses a sulfate wastewater treatment device and method, and the method comprises the following steps: primary anaerobic treatment: the wastewater to be treated is first anaerobic by adding ethanol through an anaerobic expanded bed. The sulfate reduction reaction and the methane fermentation are basically completed in a primary anaerobic reactor. Secondary anaerobic treatment: the sulfide stripping, anaerobic sludge sedimentation and secondary anaerobic further treatment are completed in a combined precipitator. The sulfate wastewater required to be used by the scheme needs to be added with sucrose and ethanol, and the process of acclimatization of sludge is also included, so that the operation is complex, the cost is high, and the popularization is not facilitated.
CN205500936U discloses high sulphate waste water backward flow processing apparatus many times, the device includes the waste water treatment pond, waste water treatment pond rear portion has connected gradually a sedimentation tank and No. two sedimentation tanks, No. two sedimentation tank rear portions are connected with backwash pump one end, the waste water treatment pond is connected to the backwash pump other end. The lateral wall of waste water treatment pond, sedimentation tank, No. two sedimentation tanks all is provided with the outlet, all be provided with level gauge and automatic valve on the outlet. The scheme has a general wastewater treatment effect, and elemental sulfur cannot be obtained, so that the economic benefit of the scheme is influenced.
Therefore, it is important to develop a device system and a treatment method for treating sulfate wastewater, which have low cost, good economy and high recovery efficiency.
Disclosure of Invention
In view of the above-mentioned shortcomings in the prior art, the present invention provides a sulfate wastewater treatment device system and a sulfate wastewater treatment method. The device and the method for treating the sulfate wastewater can treat the high-concentration sulfate wastewater, have high treatment efficiency, low energy consumption, low operation cost and high added value of products, and are easy to industrially popularize.
In the present invention, the system may also be referred to as an apparatus, a device, or a production apparatus, a combination thereof, or the like.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a sulfate wastewater treatment plant system, the system comprising: the device comprises an anaerobic reaction unit, a stripping unit, an absorption unit, a biological desulfurization unit and a gas storage unit;
the anaerobic reaction unit is respectively connected with the sulfate wastewater feeding pipeline, the blow-off unit liquid outlet, the blow-off unit liquid inlet and the absorption unit gas inlet;
the stripping unit is respectively connected with a liquid inlet of the anaerobic reaction unit, a liquid outlet of the anaerobic reaction unit, a gas inlet of the absorption unit and an outlet of the gas storage unit;
the absorption unit is respectively connected with the gas outlet of the anaerobic reaction unit, the gas outlet of the stripping unit, the liquid outlet of the biological desulfurization unit, the liquid inlet of the biological desulfurization unit and the gas inlet of the gas storage unit;
the biological desulfurization unit is respectively connected with the liquid inlet of the absorption unit, the liquid outlet of the absorption unit and the air input pipeline;
and the gas storage unit is respectively connected with the gas outlet of the absorption unit and the gas inlet of the stripping unit.
In the device system for treating the sulfate wastewater, the anaerobic reaction unit is used for treating SO in the high-concentration sulfate wastewater under the action of microorganisms4 2-And the COD is converted into a biogas containing hydrogen sulphide; the stripping unit strips hydrogen sulfide in anaerobic reaction liquid obtained by anaerobic reaction, mixes the hydrogen sulfide in the stripping liquid into the stripping gas and enters the next-stage treatment unit; the absorption unit absorbs and converts hydrogen sulfide in the gas containing the hydrogen sulfide into sulfide-containing absorption liquid by using liquid; the biological desulfurization unit converts sulfur in the sulfide-containing absorption liquid into elemental sulfur with high added value under the action of microorganisms; the gas storage unit stores gas, so that the stripping process is stably carried out, and meanwhile, the gas can be provided for downstream processes. All units are mutually matched, so that efficient, green and harmless treatment and resource treatment of the sulfate wastewater are jointly realized, and the process economy is obviously improved.
In the system provided by the invention, a closed liquid circulation is formed between the anaerobic reaction unit and the blow-off unit, a closed liquid circulation is formed between the absorption unit and the biological desulfurization unit, and a closed gas circulation is formed among the blow-off unit, the absorption unit and the gas storage unit.
The following is a preferred technical solution of the present invention, but not a limitation to the technical solution provided by the present invention, and the technical objects and advantageous effects of the present invention can be better achieved and achieved by the following preferred technical solution.
As a preferable technical scheme of the invention, the anaerobic reaction unit comprises an anaerobic reactor and an adjusting tank, a liquid outlet of the anaerobic reactor is respectively connected with an inlet of the adjusting tank and a liquid inlet of the blow-off unit, a liquid inlet of the anaerobic reactor is connected with a liquid outlet of the blow-off unit, a gas outlet of the anaerobic reactor is connected with a gas inlet of the absorption unit, an inlet of the adjusting tank is respectively connected with a liquid outlet of the anaerobic reactor and a sulfate wastewater feeding pipeline, and an outlet of the adjusting tank is connected with a liquid inlet of the blow-off unit.
Preferably, the anaerobic reactor further comprises a liquid outlet connected to a downstream section.
Preferably, a power transmission device is arranged on a pipeline between the liquid outlet of the blow-off unit and the liquid inlet of the anaerobic reactor.
Preferably, a power transmission device is arranged on a pipeline between the liquid outlet of the anaerobic reactor and the liquid inlet of the stripping unit.
Preferably, a power transmission device is arranged on a pipeline between the outlet of the regulating reservoir and the liquid inlet of the stripping unit.
Preferably, the power transmission device is a water pump.
Preferably, the anaerobic reactor comprises methanogenic activated sludge.
Preferably, the methanogenic activated sludge comprises sulfate-reducing bacteria and methanogenic bacteria. The sulfate-reducing bacteria and methanogens are conventional in the art and the specific species thereof may be selected by one skilled in the art as appropriate.
As a preferable technical scheme of the invention, the stripping unit comprises a stripping tower, a tower top liquid feed inlet of the stripping tower is connected with an outlet of the regulating tank, a tower middle liquid feed inlet of the stripping tower is connected with a liquid outlet of the anaerobic reactor, a gas outlet of the stripping tower is connected with a gas inlet of the absorption unit, and a gas inlet of the stripping tower is connected with an outlet of the gas storage unit.
Preferably, the stripping tower is a two-stage series packed tower, a tower top liquid feed inlet of the stripping tower is positioned above the upper packing layer, and a tower middle liquid feed inlet of the stripping tower is positioned between the two stages of packing layers.
As a preferable technical scheme of the invention, the absorption unit comprises a first absorption tower and a second absorption tower, a gas inlet of the first absorption tower is connected with a gas outlet of the stripping tower, a gas outlet of the first absorption tower is connected with a gas inlet of the gas storage unit, a liquid inlet of the first absorption tower is connected with a liquid outlet of the biological desulfurization unit, a liquid outlet of the first absorption tower is connected with a liquid inlet of the biological desulfurization unit, a gas inlet of the second absorption tower is connected with a gas outlet of the anaerobic reactor, a gas outlet of the second absorption tower is connected with a gas inlet of the gas storage unit, a liquid inlet of the second absorption tower is connected with a liquid outlet of the biological desulfurization unit, and a liquid outlet of the second absorption tower is connected with a liquid inlet of the biological desulfurization unit.
In the present invention, "first" and "second" in the first absorption tower and the second absorption tower are only for the sake of naming, and are not intended to limit the number of absorption towers.
Preferably, a power transmission device is arranged between the liquid outlet of the biological desulfurization unit and the liquid inlet of the absorption unit.
Preferably, the power transmission device is a water pump.
As a preferable technical scheme of the invention, the biological desulfurization unit comprises a biological desulfurization reactor and a settling tank, wherein a liquid inlet of the biological desulfurization reactor is respectively connected with a liquid outlet of the first absorption tower and a liquid outlet of the second absorption tower, a liquid outlet of the biological desulfurization reactor is connected with a liquid inlet of the settling tank, a gas inlet of the biological desulfurization reactor is connected with an air input pipeline, a liquid inlet of the settling tank is connected with a liquid outlet of the biological desulfurization reactor, and a liquid outlet of the settling tank is connected with a liquid inlet of the first absorption tower.
Preferably, the biological desulfurization reactor is also provided with a tail gas outlet.
Preferably, the air input pipeline is provided with a power transmission device.
Preferably, the power delivery means is an air pump.
Preferably, the bottom of the settling tank is also provided with an elemental sulfur outlet.
Preferably, the biological desulfurization reactor contains sulfur oxidizing bacteria. The sulfur oxidizing bacteria are conventional bacteria in the field, and the specific species can be selected by a person skilled in the art according to the situation.
Preferably, the sulfur oxidizing bacteria is a pluripotent Vibrio thiolyticus D301(Thioalkalivibrio versutus D301). The multipotent Vibrio Sulforum D301 (Thiolalkalivibrio versutus D301) is the prior art (see paragraphs 0004-0005 and 0013 of CN 105483110A), and the skilled person can obtain the bacterium according to the related description of CN 105483110A.
As a preferable technical solution of the present invention, the gas storage unit includes a gas holder, a gas inlet of the gas holder is connected to a gas outlet of the first absorption tower and a gas outlet of the second absorption tower, respectively, and a gas outlet of the gas holder is connected to a gas inlet of the stripping tower.
Preferably, the gas cabinet is further provided with a gas outlet connected with the boiler.
Preferably, a power transmission device is arranged on a pipeline between the gas outlet of the gas holder and the gas inlet of the stripping tower.
Preferably, the power transmission device is a booster fan.
In a second aspect, the present invention provides a method of treating a sulfate wastewater treatment plant system as described in the first aspect, the method comprising the steps of:
(1) anaerobic desulfurization is carried out on the sulfate wastewater to obtain methane containing hydrogen sulfide and anaerobic reaction liquid;
(2) carrying out air stripping on the anaerobic reaction liquid in the step (1) to obtain air stripping gas containing hydrogen sulfide and air stripping wastewater;
(3) absorbing the methane containing hydrogen sulfide in the step (1) and the stripping gas containing hydrogen sulfide in the step (2) to obtain sulfide absorption liquid and purified gas;
(4) carrying out biological sulfur oxidation on the sulfide absorption liquid in the step (3) under an aeration condition to obtain elemental sulfur and clear liquid;
(5) and (4) storing the purified gas obtained in the step (3) and recycling the purified gas as stripping gas to the stripping step.
High treatment efficiency, low energy consumption, low operation cost, high added value of products and easy industrialized popularization.
As a preferable technical scheme of the invention, the concentration of the sulfate in the sulfate wastewater in the step (1) is more than 1500mg/L, such as 1510mg/L, 1800mg/L, 2000mg/L, 2500mg/L, 3000mg/L, 3500mg/L, 4000mg/L or 4500 mg/L. In the present invention, the sulfate concentration is calculated as the sulfate group concentration.
Preferably, the sulfate wastewater in the step (1) is acidic wastewater.
Preferably, the anaerobic desulfurization is carried out under the action of microorganisms.
Preferably, the microorganisms include sulfate-reducing bacteria and methanogens. The sulfate-reducing bacteria and methanogens are conventional in the art and the specific species thereof may be selected by one skilled in the art as appropriate. Sulfate reducing bacteria and methanogen respectively treat sulfate and COD in the high-concentration wastewater.
Preferably, in step (1), the anaerobic desulfurization has a pH of 6.0 to 8.0, such as 6.0, 6.5, 7.0, 7.5, or 8.0, but not limited to the recited values, and other values not recited within the range of values are also applicable.
Preferably, in the step (1), the obtained anaerobic reaction liquid is divided into two parts, one part is blown off, and the other part enters a downstream section.
Preferably, in the stripping in the step (2), the stripping gas is in countercurrent contact with the anaerobic reaction liquid.
Preferably, in the stripping in the step (2), the anaerobic reaction solution is added by spraying.
Preferably, in the step (2), the anaerobic reaction liquid for stripping is divided into two parts, wherein the first part is directly stripped, and the second part is mixed with the sulfate wastewater and then stripped. The sulfate wastewater refers to untreated sulfate wastewater stock solution. The pH of the second part of wastewater is lower than that of the first part of wastewater, so that more hydrogen sulfide can be blown out.
Preferably, in the step (2), the stripping is performed in a two-stage series packed tower, the anaerobic reaction liquid for stripping is divided into two parts, the first part directly enters the two-stage series packed tower from the middle part and is stripped only through a second-stage packing area, the second part is mixed with the sulfate wastewater and then enters the two-stage series packed tower from the top, and the two-stage stripping is performed through the first-stage and second-stage packing. In this way, the hydrogen sulfide in the wastewater can be fully blown off.
Preferably, in the stripping in the step (2), the stripping gas is purified biogas.
The waste water to be stripped often contains dissolved CH4Thus, after stripping, the dissolved CH in the wastewater4Is blown off, and improves CH in the blown-off gas4Thereby increasing the heat value of the biogas.
As a preferable technical scheme of the invention, the absorption liquid used in the absorption in the step (3) is alkali liquor.
Preferably, the alkali liquor is Na2CO3And NaHCO3The composition of the buffer solution.
Preferably, the pH of the alkaline solution is 8.5 to 10.5, such as 8.5, 9, 9.5 or 10.5, but not limited to the recited values, and other values not recited within this range are equally applicable.
Preferably, the biological sulfur oxidation of step (4) is carried out under the action of sulfur oxidizing bacteria.
Preferably, the sulfur oxidizing bacteria is a pluripotent Vibrio thiolyticus D301(Thioalkalivibrio versutus D301). The multipotent Vibrio sulfidicus D301 (Thiolallivibrio versutus D301) is a strain of the prior art (see paragraphs 0004, 0005 and 0013 of the specification of CN 105483110A), and can be obtained by those skilled in the art according to the related description of CN 105483110A. The sulfur oxidizing bacteria have halophilic and alkalophilic properties. Under the condition of high pH, most sulfides are HS-Is present in the form of HS-Can not enter cell membranes, so the toxicity to cells is low, and halophilic alkalophilic microorganisms have higher tolerance to sulfur bloom. HS-The reaction with elemental sulfur forms polysulfides, which are very stable at high pH. Halophilic and alkalophilic microorganisms can efficiently oxidize hydrogen sulfide under the conditions that the pH is 9.5-11.0 and the salinity reaches 10-15%, so that the energy consumption is greatly reduced. The biological sulfur produced is S8The product has good dispersibility in water and no blockage. Meanwhile, the biological sulfur can be rapidly settled within 30 seconds, and is convenient to recover.
Preferably, in step (4), the biological sulfur oxidation has an oxidation-reduction potential of-400 to-300 mV, such as-400 mV, -380mV, -360mV, -340mV, -320mV, or-300 mV, but not limited to the values recited, and other values not recited within this range of values are equally applicable. In the present invention, the aeration amount can be controlled in response to Oxidation-Reduction Potential (ORP).
Preferably, in step (4), elemental sulfur obtained by oxidizing biological sulfur and the clear solution are separated by sedimentation.
Preferably, in the step (4), the clear liquid is taken as an absorption liquid and refluxed to the absorption process in the step (3).
Preferably, in the step (4), the elemental sulfur enters a downstream sulfur recovery system for purification and recovery.
Preferably, in step (5), the stored purge gas is used for downstream energy supply in addition to being recycled back to the stripping step as stripping gas.
Preferably, in step (5), the purge gas is stored in a gas cabinet.
Preferably, the pressure of the gas cabinet remains stable.
In the invention, the purified methane in the anaerobic process is an initial source of gas in the gas holder and a gas source in the subsequent process, the blown-off gas is a part of the purified methane in the anaerobic process, and the gas returns to the gas holder after being blown off and absorbed.
As a further preferable technical solution of the treatment method of the present invention, the method comprises the steps of:
(1) controlling the pH value to be 6.0-8.0 under the action of sulfate reducing bacteria and methanogens, and carrying out anaerobic desulfurization on sulfate wastewater to obtain methane containing hydrogen sulfide and an anaerobic reaction liquid, wherein the anaerobic reaction liquid is divided into two parts, one part is blown off, and the other part enters a downstream working section;
(2) in a two-stage series packed tower, carrying out air stripping on the anaerobic reaction liquid obtained in the step (1), dividing the anaerobic reaction liquid subjected to air stripping into two parts, directly feeding one part of the anaerobic reaction liquid into the two-stage series packed tower from the middle part for spraying, carrying out air stripping only through a second-stage packing area, mixing the other part of the anaerobic reaction liquid with sulfate wastewater, feeding the other part of the anaerobic reaction liquid into the two-stage series packed tower from the top part for spraying, and carrying out two-stage air stripping through a first-stage packing and a second-stage packing to obtain air stripping gas containing hydrogen sulfide and air stripping wastewater;
wherein, the blowing gas in the blowing process is in countercurrent contact with the anaerobic reaction liquid, and the blowing gas is purified methane;
(3) absorbing the methane containing hydrogen sulfide in the step (1) and the stripping gas containing hydrogen sulfide in the step (2) by using alkali liquor with the pH value of 8.5-10.5 to obtain sulfide absorption liquid and purified gas;
wherein the alkali liquor is Na2CO3And NaHCO3A buffer solution;
(4) under the action of sulfur oxidizing bacteria, performing biological sulfur oxidation on the sulfide absorption liquid in the step (3) under an aeration condition, controlling the oxidation-reduction potential of the biological sulfur oxidation to be-400 to-300 mV, performing sedimentation separation to obtain elemental sulfur and clear liquid, allowing the elemental sulfur to enter a downstream sulfur recovery system for purification and recovery, and allowing the clear liquid as absorption liquid to flow back to the absorption process in the step (3);
(5) and (4) storing the purified gas in the step (3) in a gas holder, wherein the stored purified gas is used for downstream energy supply besides being recycled to the air stripping step as the air stripping gas.
The further preferred technical scheme provided by the invention utilizes methanogens to carry out anaerobic methanogenic fermentation, the main product is methane, the methane is blown into an anaerobic digestion system, and the generated S is2-With H2S-shaped blowing to reduce S in the system2-Not only timely removing the sulfide in the water body, relieving the inhibition of the reactor, greatly improving the processing capacity of the reactor, but also avoiding S2-The accumulation of (a) inhibits acid-forming bacteria and sulfate-reducing bacteria. The purified methane is used as blowing gas, and methane gas dissolved in the waste water can be blown out, so that the concentration of methane in the gas is improved, and the heat value of the methane is increased.
As the effect of gas stripping is influenced by the pH value of the system, the higher the pH value is, the S2-Conversion to H2The more difficult the S is, the poorer the effect of gas stripping is; if the anaerobic wastewater is subjected to certain acidification treatment, H can be effectively strengthened2S blow-off can reduce H to a greater extent2S inhibits the anaerobic process, and the pH value of the effluent of the anaerobic reactor is generally above 7.0. Therefore, the further preferable technical scheme fully mixes the effluent with the wastewater to be treated, so that the pH of the mixed solution is close to the water inlet condition, and simultaneously, the pH of the mixed solution is reduced relative to that of the effluent, thereby being more beneficial to the air stripping and leading more S2-Transformation ofTo be H2The S form enters the gas phase, and after stripping, the pH of the liquid rises and the anaerobic treatment condition is also achieved. The increase of the blow-off effect effectively relieves the system because of S2-The accumulation of the wastewater can be inhibited, and the wastewater treatment efficiency of the system is greatly improved. In addition, the pH is adjusted by mixing the inlet water and the outlet water in the process, so that the dependence on alkali is greatly reduced, and the process cost is effectively reduced. In addition, in the stripping process, the methane dissolved in the liquid is easy to be stripped and enters a gas phase, so the further preferable technical scheme carries out stripping through the methane, and the heat value of the methane can be effectively increased.
In addition, the anaerobic waste water is blown off by inert purge gas to make S2-With H2The S form is stripped off, enters a gas phase and then contains H2And S gas is desulfurized, so that the aim of thoroughly treating pollution can be fulfilled, and the recycling of sulfur resources can be realized.
Compared with the prior art, the invention has the following beneficial effects:
(1) the units of the device system for treating the sulfate wastewater are matched with each other, so that the efficient, green and harmless treatment and resource treatment of the acidic wastewater with high sulfate content are realized together, and the process economy is obviously improved;
(2) the treatment method provided by the invention reduces S through the stripping process2-The concentration of (A) inhibits the generation of anaerobic reaction, and methane in the wastewater can be further extracted, and in addition, a pH regulator is not required to be added in the anaerobic reaction process; the product obtained by the treatment method provided by the invention is elemental sulfur, so that the economy is better; the treatment method provided by the invention SO4 2-The removal rate can reach 80 percent, and the removal rate of COD can reach 65 percent.
Drawings
FIG. 1 is a schematic view of a sulfate wastewater treatment system according to example 1 of the present invention;
wherein, 1-an anaerobic reactor, 2-a regulating tank, 3-a stripping tower, 41-a first absorption tower, 42-a second absorption tower, 5-a biological desulfurization reactor, 6-a settling tank and 7-a gas holder, a solid line with an arrow in the figure represents the liquid flow direction, and a dotted line with an arrow represents the gas flow direction;
FIG. 2 shows SO in example 1 of the present invention4 2-Water inlet and outlet concentration and S2-A change in concentration;
FIG. 3 shows SO after stripping in the system of example 1 of the present invention4 2-And change in COD removal rate;
FIG. 4 shows SO in example 2 of the present invention4 2-Water inlet and outlet concentration and S2-A change in concentration;
FIG. 5 shows SO after stripping in the system of example 2 of the present invention4 2-And change in COD removal rate.
Detailed Description
In order to better illustrate the present invention and facilitate the understanding of the technical solutions of the present invention, the present invention is further described in detail below. The following examples are merely illustrative of the present invention and do not represent or limit the scope of the claims, which are defined by the claims.
The following are typical but non-limiting examples of the invention:
example 1
The sulfate wastewater treatment plant system of the present embodiment is shown in fig. 1, and comprises: the device comprises an anaerobic reaction unit, a stripping unit, an absorption unit, a biological desulfurization unit and a gas storage unit;
the anaerobic reaction unit comprises an anaerobic reactor 1 and an adjusting tank 2, a liquid outlet of the anaerobic reactor 1 is respectively connected with an inlet of the adjusting tank 2 and a liquid inlet of the stripping unit, a liquid inlet of the anaerobic reactor 1 is connected with a liquid outlet of the stripping unit, a gas outlet of the anaerobic reactor 1 is connected with a gas inlet of the absorption unit, an inlet of the adjusting tank 2 is respectively connected with a liquid outlet of the anaerobic reactor 1 and a sulfate wastewater feeding pipeline, and an outlet of the adjusting tank 2 is connected with a liquid inlet of the stripping unit; the anaerobic reactor 1 also comprises a liquid outlet connected with a downstream section; a water pump is arranged on a pipeline between a liquid outlet of the blow-off unit and a liquid inlet of the anaerobic reactor 1, a water pump is arranged on a pipeline between a liquid outlet of the anaerobic reactor 1 and a liquid inlet of the blow-off unit, a water pump is arranged on a pipeline between an outlet of the regulating tank 2 and a liquid inlet of the blow-off unit, the anaerobic reactor 1 contains methanogenic activated sludge, and the activated sludge contains sulfate reducing bacteria and methanogenic bacteria;
the stripping unit comprises a stripping tower 3, a tower top liquid feed inlet of the stripping tower 3 is connected with an outlet of the regulating tank 2, a tower middle liquid feed inlet of the stripping tower 3 is connected with a liquid outlet of the anaerobic reactor 1, a gas outlet of the stripping tower 3 is connected with a gas inlet of the absorption unit, and a gas inlet of the stripping tower 3 is connected with an outlet of the gas storage unit; the stripping tower 3 is a two-stage series packed tower, a tower top liquid feed port of the stripping tower 3 is positioned above an upper packing layer, and a tower middle liquid feed port of the stripping tower 3 is positioned between the two packing layers;
the absorption unit comprises a first absorption tower 41 and a second absorption tower 42, wherein a gas inlet of the first absorption tower 41 is connected with a gas outlet of the stripping tower 3, a gas outlet of the first absorption tower 41 is connected with a gas inlet of the gas storage unit, a liquid inlet of the first absorption tower 41 is connected with a liquid outlet of the biological desulfurization unit, a liquid outlet of the first absorption tower 41 is connected with a liquid inlet of the biological desulfurization unit, a gas inlet of the second absorption tower 42 is connected with a gas outlet of the anaerobic reactor 1, a gas outlet of the second absorption tower 42 is connected with a gas inlet of the gas storage unit, a liquid inlet of the second absorption tower 42 is connected with a liquid outlet of the biological desulfurization unit, and a liquid outlet of the second absorption tower 42 is connected with a liquid inlet of the biological desulfurization unit; a water pump is arranged between the liquid outlet of the biological desulfurization unit and the liquid inlet of the absorption unit;
the biological desulfurization unit comprises a biological desulfurization reactor 5 and a settling tank 6, wherein a liquid inlet of the biological desulfurization reactor 5 is respectively connected with a liquid outlet of a first absorption tower 41 and a liquid outlet of a second absorption tower 42, a liquid outlet of the biological desulfurization reactor 5 is connected with a liquid inlet of the settling tank 6, a gas inlet of the biological desulfurization reactor 5 is connected with an air input pipeline, a liquid inlet of the settling tank 6 is connected with a liquid outlet of the biological desulfurization reactor 5, and a liquid outlet of the settling tank 6 is connected with a liquid inlet of the first absorption tower 41; the biological desulfurization reactor 5 is also provided with a tail gas outlet; an air pump is arranged on the air input pipeline; the bottom of the settling tank 6 is also provided with an elemental sulfur outlet; the biological desulfurization reactor 5 contains a Vibrio thionatsuvialis D301 (Thioalkavibrio versutus D301);
the gas storage unit comprises a gas holder 7, a gas inlet of the gas holder 7 is respectively connected with a gas outlet of the first absorption tower 41 and a gas outlet of the second absorption tower 42, and a gas outlet of the gas holder 7 is connected with a gas inlet of the stripping tower (3); the gas holder 7 is also provided with a gas outlet connected with a boiler; a booster fan is arranged on a pipeline between the gas outlet of the gas holder 7 and the gas inlet of the stripping tower 3.
The sulfate wastewater treated in this example was simulated wastewater. The simulated wastewater composition was (in 1L wastewater): 1.0g NH4Cl,2g KH2PO4，0.05g MgCl2、0.01g FeCl3、0.01g MnSO40.5g of yeast powder and 1mL of 98% concentrated sulfuric acid. Using glucose as carbon source, and adding sodium sulfate to make SO in the liquid4 2-The highest concentration of (A) is 2000mg/L, COD/SO4 2-Is 2.0. The pH was adjusted to 5.0.
The sulfate wastewater treatment method of the embodiment comprises the following steps:
maintaining the water conservancy retention time (HRT) for 24 h. Firstly, regulating the pH value of the simulated wastewater to 6.0, then entering a system through an anaerobic adjusting tank, and starting an anaerobic process to obtain methane containing hydrogen sulfide and anaerobic reaction liquid. The biogas containing hydrogen sulfide generated by the anaerobic reactor 1 is guided into a second absorption tower for absorption and purification, the purified gas is stored in a gas holder, and the absorption liquid is subjected to biological sulfur oxidation through a biological desulfurization reactor 5 under the aeration condition to generate sulfur.
And when the anaerobic process is stable, opening the stripping system for stripping. One part of the left effluent is directly led into the middle part of a stripping tower 3 for stripping, and the other part of the left effluent enters a regulating tank 2 to be mixed with the wastewater to be treated and then is led into the top 3 part of the stripping tower for stripping. The water conservancy residence time of the system is kept unchanged, and the circulation process between the anaerobic reactor 1 and the stripping tower 2 is strengthened. Adjusting the mixing proportion of the wastewater and the effluent and adjusting the flow of each branch to ensure that the pH value of the influent water of the anaerobic reactor reaches above 6.0.
In the first stage of the experiment, the liquid circulation between the anaerobic reactor 1 and the stripping tower 3 is closed, and the waste water stripping is not carried out. Wastewater directly enters the anaerobic reactor 1 from the regulating tank 2, and the inlet SO is gradually increased4 2-The concentration is increased to a maximum concentration of 2000 mg/L.
Example SO4 2-Water inlet and outlet concentration and S2-The change in concentration is shown in FIG. 2 as a function of SO4 2-Increase in concentration, S2-The concentration gradually accumulates. However, SO4 2-The removal rate is always maintained at a low level. When water is fed in SO4 2-When the concentration is 2000mg/L, the highest removal rate is only about 60 percent.
And in the second stage, opening a waste water circulating system and a stripping system, stripping the anaerobic reaction liquid to obtain stripping gas containing hydrogen sulfide and stripping waste water, absorbing methane containing hydrogen sulfide and stripping gas containing hydrogen sulfide to obtain sulfide absorption liquid and purified gas, carrying out biological sulfur oxidation on the sulfide absorption liquid under the aeration condition to obtain elemental sulfur and clear liquid, storing the purified gas, circulating the purified gas back to the stripping step as stripping gas, and enabling the system to enter a stable state.
SO after stripping in the system of the embodiment4 2-The change of the COD removal rate is shown in FIG. 3, the operation is continued for 25 days, and SO is added4 2-The removal rate was increased from 49% to 80%, and the removal rate of COD was also increased from 40% to 60%. And (4) introducing the stripping gas into a biological sulfur oxidation system for treatment to obtain elemental sulfur.
The yield of elemental sulfur in this example was 2.1 g/L/day after the system stripping.
Example 2
The system of the sulfate wastewater treatment apparatus of this example was the same as that of example 1.
The sulfate wastewater treated by the embodiment is real pharmaceutical wastewater, and the wastewater parameter is SO4 2-The concentration is 3000-3500mg/L, the COD concentration is 8000-10000 mg/L.
The specific steps of the sulfate wastewater treatment method of the present example refer to example 1, wherein:
maintaining the water conservancy retention time (HRT) for 24 h. The waste water enters from the bottom of the anaerobic reactor for anaerobic treatment.
In the first stage, the anaerobic reactor is used to treat high concentration pharmaceutical waste water, the system is continuously and stably operated for 20 days, and in the process, the waste water stripping system is closed.
And in the second stage, opening the waste water stripping system for stripping, operating the biological sulfur oxidation system to obtain elemental sulfur, and treating the stripping gas.
SO in this example4 2-Water inlet and outlet concentration and S2-The change in concentration is shown in FIG. 4, in the first 20 days, SO4 2-The removal rate of (2) is about 50%, yielding water S2-The concentration is about 500mg/L, and SO is generated after the start of stripping4 2-The removal rate of the wastewater is improved to 85 percent, and SO in the effluent water4 2-The content of (A) is less than 600mg/L, however, S in the effluent water2-There was no significant increase. This is because the formed sulfides are blown off into the gas phase.
SO after stripping of the System in this example4 2-The change from the COD removal rate is shown in FIG. 5, after the blow-off was turned on, the system COD removal rate increased from 40% to about 65%, indicating that the blow-off was beneficial to relieving the system of inhibition. The blown gas is treated by a biological sulfur oxidation system, and the yield of elemental sulfur can reach 3.5 g/L/day.
After the system stripping, SO of this example4 2-The removal rate was 81%.
Example 3
The system of the sulfate wastewater treatment apparatus of this example was the same as that of example 1.
The sulfate wastewater treated by the embodiment is real pharmaceutical wastewater, and the wastewater parameter is SO4 2-The concentration is 3000-3500mg/L, the COD concentration is 8000-10000 mg/L.
The sulfate wastewater treatment method of the embodiment comprises the following steps:
(1) maintaining water conservancy residence time (HRT) for 24h, controlling pH to 6.0 under the action of sulfate reducing bacteria and methanogen, and performing anaerobic desulfurization on sulfate wastewater to obtain biogas containing hydrogen sulfide and anaerobic reaction liquid, wherein the anaerobic reaction liquid is divided into two parts, one part is blown off, and the other part enters a downstream working section;
(2) in a two-stage series packed tower, carrying out air stripping on the anaerobic reaction liquid obtained in the step (1), dividing the anaerobic reaction liquid subjected to air stripping into two parts, directly feeding one part of the anaerobic reaction liquid into the two-stage series packed tower from the middle part for spraying, carrying out air stripping only through a second-stage packing area, mixing the other part of the anaerobic reaction liquid with sulfate wastewater, feeding the other part of the anaerobic reaction liquid into the two-stage series packed tower from the top part for spraying, and carrying out two-stage air stripping through a first-stage packing and a second-stage packing to obtain air stripping gas containing hydrogen sulfide and air stripping wastewater;
wherein, the blowing gas in the blowing process is in countercurrent contact with the anaerobic reaction liquid, and the blowing gas is purified methane;
(3) absorbing the methane containing hydrogen sulfide in the step (1) and the stripping gas containing hydrogen sulfide in the step (2) by using alkali liquor with the pH value of 8.5 to obtain sulfide absorption liquid and purified gas;
wherein the alkali liquor is Na2CO3And NaHCO3A buffer solution;
(4) under the action of sulfur oxidizing bacteria, carrying out biological sulfur oxidation on the sulfide absorption liquid in the step (3) under an aeration condition, controlling the oxidation-reduction potential of the biological sulfur oxidation to be-400 mV, carrying out settling separation to obtain elemental sulfur and clear liquid, allowing the elemental sulfur to enter a downstream sulfur recovery system for purification and recovery, and allowing the clear liquid as an absorption liquid to flow back to the absorption process in the step (3);
(5) and (4) storing the purified gas in the step (3) in a gas holder, wherein the stored purified gas is used for downstream energy supply besides being recycled to the air stripping step as the air stripping gas.
In this example, SO4 2-The removal rate is 79 percent, the COD removal rate is 62 percent, and the yield of the elemental sulfur is 3.0 g/L/day.
Example 4
The system of the sulfate wastewater treatment apparatus of this example was the same as that of example 1.
This exampleThe treated sulfate wastewater is real pharmaceutical wastewater, and the wastewater parameter is SO4 2-The concentration is 3000-3500mg/L, the COD concentration is 8000-10000 mg/L.
The sulfate wastewater treatment method of the embodiment comprises the following steps:
(1) maintaining water conservancy residence time (HRT) for 24h, controlling pH to 8.0 under the action of sulfate reducing bacteria and methanogen, and performing anaerobic desulfurization on sulfate wastewater to obtain biogas containing hydrogen sulfide and anaerobic reaction liquid, wherein the anaerobic reaction liquid is divided into two parts, one part is blown off, and the other part enters a downstream working section;
(2) in a two-stage series packed tower, carrying out air stripping on the anaerobic reaction liquid obtained in the step (1), dividing the anaerobic reaction liquid subjected to air stripping into two parts, directly feeding one part of the anaerobic reaction liquid into the two-stage series packed tower from the middle part for spraying, carrying out air stripping only through a second-stage packing area, mixing the other part of the anaerobic reaction liquid with sulfate wastewater, feeding the other part of the anaerobic reaction liquid into the two-stage series packed tower from the top part for spraying, and carrying out two-stage air stripping through a first-stage packing and a second-stage packing to obtain air stripping gas containing hydrogen sulfide and air stripping wastewater;
wherein, the blowing gas in the blowing process is in countercurrent contact with the anaerobic reaction liquid, and the blowing gas is purified methane;
(3) absorbing the methane containing hydrogen sulfide in the step (1) and the stripping gas containing hydrogen sulfide in the step (2) by using alkali liquor with the pH value of 10.5 to obtain sulfide absorption liquid and purified gas;
wherein the alkali liquor is Na2CO3And NaHCO3A buffer solution;
(4) under the action of sulfur oxidizing bacteria, carrying out biological sulfur oxidation on the sulfide absorption liquid in the step (3) under an aeration condition, controlling the oxidation-reduction potential of the biological sulfur oxidation to be-300 mV, carrying out settling separation to obtain elemental sulfur and clear liquid, allowing the elemental sulfur to enter a downstream sulfur recovery system for purification and recovery, and allowing the clear liquid as an absorption liquid to flow back to the absorption process in the step (3);
(5) and (4) storing the purified gas in the step (3) in a gas holder, wherein the stored purified gas is used for downstream energy supply besides being recycled to the air stripping step as the air stripping gas.
In this embodiment, the pH in step (1) is relatively high, SO that the sulfate wastewater treatment effect is reduced, and the SO in this embodiment4 2-The removal rate is 60%, the COD removal rate is 55%, and the yield of elemental sulfur is 2.2 g/L/day.
Example 5
The system of the sulfate wastewater treatment apparatus of this example was the same as that of example 1.
The sulfate wastewater treated by the embodiment is real pharmaceutical wastewater, and the wastewater parameter is SO4 2-The concentration is 3000-3500mg/L, the COD concentration is 8000-10000 mg/L.
The sulfate wastewater treatment method of the embodiment comprises the following steps:
(1) maintaining water conservancy residence time (HRT) for 24h, controlling pH to 7.0 under the action of sulfate reducing bacteria and methanogen, and performing anaerobic desulfurization on sulfate wastewater to obtain biogas containing hydrogen sulfide and anaerobic reaction liquid, wherein the anaerobic reaction liquid is divided into two parts, one part is blown off, and the other part enters a downstream working section;
(2) in a two-stage series packed tower, carrying out air stripping on the anaerobic reaction liquid obtained in the step (1), dividing the anaerobic reaction liquid subjected to air stripping into two parts, directly feeding one part of the anaerobic reaction liquid into the two-stage series packed tower from the middle part for spraying, carrying out air stripping only through a second-stage packing area, mixing the other part of the anaerobic reaction liquid with sulfate wastewater, feeding the other part of the anaerobic reaction liquid into the two-stage series packed tower from the top part for spraying, and carrying out two-stage air stripping through a first-stage packing and a second-stage packing to obtain air stripping gas containing hydrogen sulfide and air stripping wastewater;
wherein, the blowing gas in the blowing process is in countercurrent contact with the anaerobic reaction liquid, and the blowing gas is purified methane;
(3) absorbing the methane containing hydrogen sulfide in the step (1) and the stripping gas containing hydrogen sulfide in the step (2) by using alkali liquor with the pH value of 9.5 to obtain sulfide absorption liquid and purified gas;
wherein the alkali liquor is Na2CO3And NaHCO3A buffer solution;
(4) under the action of sulfur oxidizing bacteria, carrying out biological sulfur oxidation on the sulfide absorption liquid in the step (3) under an aeration condition, controlling the oxidation-reduction potential of the biological sulfur oxidation to be-350 mV, carrying out settling separation to obtain elemental sulfur and clear liquid, allowing the elemental sulfur to enter a downstream sulfur recovery system for purification and recovery, and allowing the clear liquid as an absorption liquid to flow back to the absorption process in the step (3);
(5) and (4) storing the purified gas in the step (3) in a gas holder, wherein the stored purified gas is used for downstream energy supply besides being recycled to the air stripping step as the air stripping gas.
In this example, SO4 2-The removal rate was 78%, the COD removal rate was 61%, and the yield of elemental sulfur was 3.4 g/L/day.
By combining the above embodiments, the device system for treating sulfate wastewater and the treatment method thereof provided by the invention realize efficient, green, harmless and recycling treatment of acidic high-sulfate wastewater, and significantly improve the process economy. Especially, the air stripping process plays an important role in achieving good wastewater treatment effect.
The applicant states that the present invention is illustrated by the above examples to show the detailed process equipment and process flow of the present invention, but the present invention is not limited to the above detailed process equipment and process flow, i.e. it does not mean that the present invention must rely on the above detailed process equipment and process flow to be implemented. It should be understood by those skilled in the art that any modification of the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.

Claims (45)

1. A method of treating sulfate wastewater with a sulfate wastewater treatment plant system, the method comprising the steps of:
(1) anaerobic desulfurization is carried out on the sulfate wastewater to obtain methane containing hydrogen sulfide and anaerobic reaction liquid;
(2) carrying out air stripping on the anaerobic reaction liquid in the step (1) to obtain air stripping gas containing hydrogen sulfide and air stripping wastewater;
(3) absorbing the methane containing hydrogen sulfide in the step (1) and the stripping gas containing hydrogen sulfide in the step (2) to obtain sulfide absorption liquid and purified gas;
(4) carrying out biological sulfur oxidation on the sulfide absorption liquid in the step (3) under an aeration condition to obtain elemental sulfur and clear liquid;
(5) storing the purified gas in the step (3) and recycling the purified gas as stripping gas to the stripping step;
in the step (2), the anaerobic reaction liquid for stripping is divided into two parts, wherein the first part is directly stripped, and the second part is mixed with sulfate wastewater and then stripped; the stripping is carried out in two-stage series packed towers, anaerobic reaction liquid for stripping is divided into two parts, the first part directly enters the two-stage series packed towers from the middle part and is stripped only through a second-stage packed area, the second part is mixed with sulfate wastewater and then enters the two-stage series packed towers from the top, and the two-stage stripping is carried out through first-stage and second-stage packing;
the system comprises: the device comprises an anaerobic reaction unit, a stripping unit, an absorption unit, a biological desulfurization unit and a gas storage unit;
the anaerobic reaction unit is respectively connected with the sulfate wastewater feeding pipeline, the blow-off unit liquid outlet, the blow-off unit liquid inlet and the absorption unit gas inlet;
the stripping unit is respectively connected with a liquid inlet of the anaerobic reaction unit, a liquid outlet of the anaerobic reaction unit, a gas inlet of the absorption unit and an outlet of the gas storage unit;
the absorption unit is respectively connected with the gas outlet of the anaerobic reaction unit, the gas outlet of the stripping unit, the liquid outlet of the biological desulfurization unit, the liquid inlet of the biological desulfurization unit and the gas inlet of the gas storage unit;
the biological desulfurization unit is respectively connected with the liquid inlet of the absorption unit, the liquid outlet of the absorption unit and the air input pipeline;
the gas storage unit is respectively connected with the gas outlet of the absorption unit and the gas inlet of the stripping unit;
the anaerobic reaction unit comprises an anaerobic reactor (1) and an adjusting tank (2); the stripping unit comprises a stripping tower (3);
the stripping tower (3) is a two-stage series packed tower, a tower top liquid feed port of the stripping tower (3) is positioned above an upper packing layer, and a tower middle liquid feed port of the stripping tower (3) is positioned between the two packing layers;
the absorption unit comprises a first absorption tower (41) and a second absorption tower (42), wherein a gas inlet of the first absorption tower (41) is connected with a gas outlet of the stripping tower (3), a gas outlet of the first absorption tower (41) is connected with a gas inlet of the gas storage unit, a liquid inlet of the first absorption tower (41) is connected with a liquid outlet of the biological desulfurization unit, a liquid outlet of the first absorption tower (41) is connected with a liquid inlet of the biological desulfurization unit, a gas inlet of the second absorption tower (42) is connected with a gas outlet of the anaerobic reactor (1), a gas outlet of the second absorption tower (42) is connected with a gas inlet of the gas storage unit, a liquid inlet of the second absorption tower (42) is connected with a liquid outlet of the biological desulfurization unit, and a liquid outlet of the second absorption tower (42) is connected with a liquid inlet of the biological desulfurization unit.
2. The method according to claim 1, wherein the anaerobic reaction unit comprises an anaerobic reactor (1) and a regulating tank (2), the liquid outlet of the anaerobic reactor (1) is connected with the inlet of the regulating tank (2) and the liquid inlet of the blow-off unit respectively, the liquid inlet of the anaerobic reactor (1) is connected with the liquid outlet of the blow-off unit, the gas outlet of the anaerobic reactor (1) is connected with the gas inlet of the absorption unit, the inlet of the regulating tank (2) is connected with the liquid outlet of the anaerobic reactor (1) and a sulfate wastewater feeding pipeline respectively, and the outlet of the regulating tank (2) is connected with the liquid inlet of the blow-off unit.
3. A method according to claim 1, characterized in that the anaerobic reactor (1) further comprises a liquid outlet connected to a downstream section.
4. A method according to claim 1, characterized in that a power transmission means is provided in the conduit between the liquid outlet of the blow-off unit and the liquid inlet of the anaerobic reactor (1).
5. A method according to claim 1, characterized in that a power transmission means is provided in the conduit between the liquid outlet of the anaerobic reactor (1) and the liquid inlet of the blow-off unit.
6. A method according to claim 1, characterized in that a power transmission means is provided in the line between the outlet of the conditioning tank (2) and the liquid inlet of the blow-off unit.
7. The method of claim 6, wherein the power delivery device is a water pump.
8. A method according to claim 1, characterized in that the anaerobic reactor (1) contains methanogenic activated sludge.
9. The method of claim 8, wherein the methanogenic activated sludge comprises sulfate-reducing bacteria and methanogenic bacteria.
10. The method according to claim 1, wherein the stripping unit comprises a stripping tower (3), a top liquid feed port of the stripping tower (3) is connected with an outlet of the regulating tank (2), a middle liquid feed port of the stripping tower (3) is connected with a liquid outlet of the anaerobic reactor (1), a gas outlet of the stripping tower (3) is connected with a gas inlet of the absorption unit, and a gas inlet of the stripping tower (3) is connected with an outlet of the gas storage unit.
11. The method of claim 1, wherein a power delivery device is provided between the liquid outlet of the biological desulfurization unit and the liquid inlet of the absorption unit.
12. The method of claim 11, wherein the power delivery device is a water pump.
13. The method according to claim 1, wherein the biological desulfurization unit comprises a biological desulfurization reactor (5) and a settling tank (6), wherein a liquid inlet of the biological desulfurization reactor (5) is connected with a liquid outlet of the first absorption tower (41) and a liquid outlet of the second absorption tower (42), respectively, a liquid outlet of the biological desulfurization reactor (5) is connected with a liquid inlet of the settling tank (6), a gas inlet of the biological desulfurization reactor (5) is connected with an air input pipeline, a liquid inlet of the settling tank (6) is connected with a liquid outlet of the biological desulfurization reactor (5), and a liquid outlet of the settling tank (6) is connected with a liquid inlet of the first absorption tower (41).
14. The method according to claim 13, characterized in that the biological desulfurization reactor (5) is also provided with a tail gas discharge outlet.
15. The method of claim 13, wherein the air input line is provided with a power delivery device.
16. The method of claim 15, wherein the power delivery device is an air pump.
17. Method according to claim 13, characterized in that the bottom of the settler (6) is also provided with an elemental sulphur discharge.
18. The method according to claim 13, characterized in that the biological desulfurization reactor (5) contains sulfur oxidizing bacteria.
19. The method as claimed in claim 18, wherein the sulfur oxidizing bacteria is Vibrio thiolyticus D301.
20. The method according to claim 1, wherein the gas storage unit comprises a gas holder (7), a gas inlet of the gas holder (7) is connected to a gas outlet of the first absorption tower (41) and a gas outlet of the second absorption tower (42), respectively, and a gas outlet of the gas holder (7) is connected to a gas inlet of the stripping tower (3).
21. A method according to claim 20, characterized in that the gas holder (7) is further provided with a gas outlet connected to a boiler.
22. A method according to claim 20, characterized in that a power transmission means is provided in the line between the gas outlet of the gas holder (7) and the gas inlet of the stripping tower (3).
23. The method of claim 22, wherein the power delivery device is a booster fan.
24. The method according to claim 1, wherein the sulfate concentration in the sulfate wastewater of step (1) is > 1500 mg/L.
25. The method according to claim 1, wherein the sulfate wastewater of step (1) is an acidic wastewater.
26. The method of claim 1, wherein the anaerobic desulfurization is performed under the action of microorganisms.
27. The method of claim 26, wherein the microorganisms comprise sulfate-reducing bacteria and methanogens.
28. The method of claim 1, wherein in step (1), the pH of the anaerobic desulfurization is 6.0-8.0.
29. The method according to claim 21, wherein in the step (1), the obtained anaerobic reaction solution is divided into two parts, one part is subjected to stripping, and the other part enters a downstream section.
30. The method as claimed in claim 23, wherein in the stripping in the step (2), the stripping gas is in countercurrent contact with the anaerobic reaction solution.
31. The method as claimed in claim 23, wherein the anaerobic reaction solution is added by spraying in the stripping in step (2).
32. The method of claim 1, wherein in the step (2), the gas is purified methane.
33. The method according to claim 1, wherein the absorption liquid used in the absorption in the step (3) is a lye.
34. The method of claim 33, wherein the lye is Na2CO3And NaHCO3The composition of the buffer solution.
35. The method of claim 33, wherein the pH of the alkaline solution is 8.5 to 10.5.
36. The method according to claim 1, wherein the biological sulfur oxidation of step (4) is carried out under the action of sulfur oxidizing bacteria.
37. The method of claim 36, wherein the sulfur oxidizing bacteria is Vibrio thioalkali D301.
38. The method according to claim 1, wherein in step (4), the oxidation-reduction potential of biological sulfur oxidation is-400 to-300 mV.
39. The method according to claim 1, wherein in step (4), elemental sulfur obtained by oxidation of biological sulfur is separated from the supernatant by sedimentation.
40. The method according to claim 1, wherein in the step (4), the clear liquid is refluxed to the absorption process in the step (3) as an absorption liquid.
41. The method of claim 1, wherein in step (4), the elemental sulfur is subjected to a downstream sulfur recovery system for clean recovery.
42. The method of claim 1, wherein in step (5), the stored purge gas is used for downstream energy supply in addition to being recycled back to the stripping step as the stripping gas.
43. The method of claim 1, wherein in step (5), the purge gas is stored in a gas cabinet.
44. The method of claim 43, wherein the pressure of the gas cabinet remains constant.
45. Method according to claim 1, characterized in that it comprises the following steps:
(1) controlling the pH value to be 6.0-8.0 under the action of sulfate reducing bacteria and methanogens, and carrying out anaerobic desulfurization on sulfate wastewater to obtain methane containing hydrogen sulfide and an anaerobic reaction liquid, wherein the anaerobic reaction liquid is divided into two parts, one part is blown off, and the other part enters a downstream working section;
(2) in a two-stage series packed tower, carrying out air stripping on the anaerobic reaction liquid obtained in the step (1), dividing the anaerobic reaction liquid subjected to air stripping into two parts, directly feeding one part of the anaerobic reaction liquid into the two-stage series packed tower from the middle part for spraying, carrying out air stripping only through a second-stage packing area, mixing the other part of the anaerobic reaction liquid with sulfate wastewater, feeding the other part of the anaerobic reaction liquid into the two-stage series packed tower from the top part for spraying, and carrying out two-stage air stripping through a first-stage packing and a second-stage packing to obtain air stripping gas containing hydrogen sulfide and air stripping wastewater;
wherein, the blowing gas in the blowing process is in countercurrent contact with the anaerobic reaction liquid, and the blowing gas is purified methane;
(3) absorbing the methane containing hydrogen sulfide in the step (1) and the stripping gas containing hydrogen sulfide in the step (2) by using alkali liquor with the pH value of 8.5-10.5 to obtain sulfide absorption liquid and purified gas;
wherein the alkali liquor is Na2CO3And NaHCO3A buffer solution;
(4) under the action of sulfur oxidizing bacteria, performing biological sulfur oxidation on the sulfide absorption liquid in the step (3) under an aeration condition, controlling the oxidation-reduction potential of the biological sulfur oxidation to be-400 to-300 mV, performing sedimentation separation to obtain elemental sulfur and clear liquid, allowing the elemental sulfur to enter a downstream sulfur recovery system for purification and recovery, and allowing the clear liquid as absorption liquid to flow back to the absorption process in the step (3);
(5) and (4) storing the purified gas in the step (3) in a gas holder, wherein the stored purified gas is used for downstream energy supply besides being recycled to the air stripping step as the air stripping gas.
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