Cooperative treatment method and system for malodorous gas and wastewater

Abstract

The invention provides a malodorous gas and wastewater cooperative treatment method and system.The method comprises the steps that malodorous gas and air are mixed according to the volume ratio of 1: (3-15), and mixed gas is obtained; feeding the wastewater into a biochemical pool, adding activated carbon into the biochemical pool, aerating the mixed gas into the biochemical pool, and carrying out biochemical reaction; wherein the diameter of the aeration bubbles is 1-3mm, and the dissolved oxygen concentration of the wastewater in the biochemical pool is 0.5-3mg / L; after the reaction is finished, the sludge in the biochemical pool is discharged and treated, so that the activated carbon in the sludge is regenerated. According to the invention, malodorous gas treatment and wastewater biochemical treatment of a sewage treatment plant are organically combined, so that cooperative control of waste gas and wastewater pollution is realized, repeated construction of a malodorous pollution treatment system is avoided, and meanwhile, a carbon source of a biological treatment unit is supplemented; the activated carbon regeneration process is simple, low in energy consumption and free of environmental pollution risk.

Description

Technical Field

[0001] The present invention relates to the technical field of waste gas and wastewater treatment, and particularly relates to a method and a system for co - treating malodorous gas and wastewater. Background Art

[0002] It is very difficult for the sewage collection system and sewage treatment plants of oil and petrochemical enterprises to be completely airtight. Volatile pollutants escape from the water body through pipelines, structures, and equipment, etc., and form waste gas emissions, becoming an important source of malodorous pollutant emissions. The treatment of malodorous pollution in sewage treatment plants has become an important part of the pollution prevention and control system of oil and petrochemical enterprises.

[0003] There are two types of malodorous gases emitted by sewage treatment plants: one is the high - concentration odor emitted from physical and chemical facilities, sewage oil tanks, scum ponds, etc. The composition is mainly non - methane total hydrocarbons, and the concentrations of malodorous substances such as hydrogen sulfide, ammonia, and organic sulfides are also relatively high, which is suitable for treatment by combustion methods (catalytic oxidation combustion, regenerative thermal oxidation combustion, etc.); the other is the low - concentration odor emitted from biochemical facilities and sludge ponds / rooms, etc., which is mostly treated by methods such as alkali liquor washing, adsorption, and biological deodorization.

[0004] CN114210174A, CN1768924A, and CN111686683A use absorbents and adsorbents to treat malodorous and organic waste gases. After the materials are saturated with adsorption, they still need high - temperature activation, which has high costs, takes a long time, and there is a hidden danger of secondary pollution of gas desorption.

[0005] Biological deodorization technology is also the main malodorous treatment technology currently used. CN110201204A provides a preparation method of a biological deodorant carrier, which can be used in combination with biological deodorant bacteria to treat malodorous pollution; CN215365076U discloses an improved biological deodorization and biological deodorization system. However, generally speaking, after the malodorous gas is collected, a special treatment and disposal system needs to be built. To meet the requirements of high treatment efficiency and secondary pollution control, the cost will inevitably increase. Therefore, effectively using existing facilities for malodorous treatment is an effective way to reduce treatment costs. Summary of the Invention

[0006] In order to solve the problems of high cost and low efficiency in treating low - concentration malodorous gases in sewage treatment plants, the purpose of the present invention is to provide a method and a system for co - treating malodorous gas and wastewater.

[0007] To achieve the above - mentioned purpose, the present invention provides a method for co - treating malodorous gas and wastewater, which includes the following steps:

[0008] S1. Mix the malodorous gas and air in a volume ratio of 1:3 - 15 to obtain a mixed gas;

[0009] S2. Feed the wastewater into the biochemical pool, add activated carbon into the biochemical pool, and then aerate the mixed gas into the biochemical pool for biochemical reaction; wherein, the diameter of the aeration bubbles is 1-3 mm, and the dissolved oxygen concentration of the wastewater in the biochemical pool is 0.5-3 mg / L;

[0010] S3. After the reaction is completed, discharge the sludge in the biochemical pool and treat it to regenerate the activated carbon in the sludge.

[0011] The present invention uses the biochemical unit of the sewage treatment plant to biologically degrade the malodorous gas, achieving the goal of efficient and low-cost treatment of malodorous pollution control, and providing an effective path for the coordinated control of oil and petrochemical waste gas and wastewater pollution. All sewage treatment plants are equipped with efficient biochemical units, and most substances in the malodorous gas can be used as effective carbon sources for microorganisms. Therefore, the organic combination of malodorous gas treatment and wastewater biochemical treatment is not only an effective measure to achieve the coordinated control of waste gas and wastewater pollution, but also an effective path to reduce energy consumption and carbon emissions.

[0012] There are residual strongly polar and highly biotoxic substances in the malodorous gas. If directly mixed into the biochemical system, neither anaerobic microorganisms nor aerobic microorganisms can degrade them, and it may cause microbial poisoning, making it difficult for the biochemical unit to operate stably; the malodorous gas contains acidic and alkaline substances such as ammonia and hydrogen sulfide, resulting in large fluctuations in the pH value of the wastewater. In response, the present invention first uses activated carbon for malodorous gas to capture various substances in the pores of the activated carbon, avoiding direct contact with microorganisms, but forming active reaction sites on the activated carbon interface / pore surface, resisting pollution shock, ensuring the stable operation of the system and improving the efficient degradation efficiency of key pollutants. In addition, the method of the present invention only needs to supplement a small amount of activated carbon, and most of the activated carbon can be obtained through regeneration, activation and other treatments.

[0013] In the above-mentioned method for the coordinated treatment of malodorous gas and wastewater, preferably, the components of the malodorous gas include: ammonia 40-60 mg / m 3 , hydrogen sulfide 20-30 mg / m 3 , total non-methane hydrocarbons 350-450 mg / m 3 , aromatic hydrocarbons 50-150 mg / m 3 , organic sulfur compounds 30-120 mg / m 3 .

[0014] In the above-mentioned method for the coordinated treatment of malodorous gas and wastewater, preferably, the malodorous gas is the malodorous gas from the flotation tank of refinery wastewater.

[0015] In the above-mentioned method for the coordinated treatment of malodorous gas and wastewater, preferably, the COD of the wastewater entering the biochemical pool is 100-250 mg / L.

[0016] In the above-mentioned co-treatment method of malodorous gas and wastewater, preferably, based on the volume of the wastewater in the biochemical tank, the dosage of activated carbon is 0.05 - 0.4 g / L.

[0017] In the above-mentioned co-treatment method of malodorous gas and wastewater, preferably, during the biochemical reaction, the temperature of the wastewater in the biochemical tank is 25 - 38 °C. At this temperature, the synergistic effect of activated carbon adsorption and biodegradation is the best, and the removal efficiency of malodorous concentration and wastewater COD is high.

[0018] In the above-mentioned co-treatment method of malodorous gas and wastewater, preferably, the treatment method of the sludge in S3 includes: adding an inorganic demulsifier to the sludge, and then adding a slow-release oxidant for an oxidation reaction, followed by dehydration separation and drying to obtain regenerated activated carbon.

[0019] In the above-mentioned co-treatment method of malodorous gas and wastewater, preferably, based on the total mass of the sludge, the dosage of the inorganic demulsifier is 0.01 - 1.5 g / L.

[0020] In the above-mentioned co-treatment method of malodorous gas and wastewater, preferably, the inorganic demulsifier includes sodium silicate and / or calcium chloride.

[0021] In the above-mentioned co-treatment method of malodorous gas and wastewater, preferably, based on the total mass of the sludge, the dosage of the slow-release oxidant is 0.5 - 5 g / L.

[0022] In the above-mentioned co-treatment method of malodorous gas and wastewater, preferably, the slow-release oxidant includes at least one of calcium peroxide, magnesium peroxide, and sodium hypochlorite.

[0023] In the above-mentioned co-treatment method of malodorous gas and wastewater, preferably, the oxidation reaction temperature is 40 - 80 °C, and the time is 6 - 24 h.

[0024] In the above-mentioned co-treatment method of malodorous gas and wastewater, preferably, the dehydration separation method is centrifugation, and the centrifugation speed is 1000 - 5000 rmp.

[0025] In the above-mentioned co-treatment method of malodorous gas and wastewater, preferably, the drying temperature is 55 - 95 °C, and the time is 4 - 12 h.

[0026] In the above-mentioned co-treatment method of malodorous gas and wastewater, preferably, the unreacted malodorous gas in the biochemical tank in S2 is returned to S1 to be mixed with air again.

[0027] According to the specific embodiments of the present invention, preferably, the above-mentioned co-treatment method of malodorous gas and wastewater includes the following steps:

[0028] S1. After the low-concentration malodorous gas is collected, it is mixed with the air from the air-blowing system through a multi-airway mixer and then transported to the biochemical pool together according to the flow ratio. The multi-airway mixer includes a malodorous gas inlet, an air-blowing air inlet, and a mixed gas outlet, and a rotameter is used to control the gas flow. The flow ratio of the malodorous gas to the air-blowing aeration air is 1:3 - 1:15. The biochemical pool can be an activated sludge biochemical pool with activated carbon added.

[0029] S2. The mixture of the malodorous gas and air is distributed in the biochemical pool through an aerator, generating bubbles with a diameter of 1 - 3 mm, maintaining the dissolved oxygen concentration at 0.5 - 3 mg / L, and inhibiting the overflow of volatile organic compounds. The biochemical pool is equipped with a malodorous gas collection system, and the collected malodorous gas is transported to S1.

[0030] S3. After the reaction ends, after the sludge is discharged from the biochemical pool with activated carbon added, an inorganic demulsifier is added to remove oil, and then a slow-release oxidant is added. Through an oxidation reaction, endocrine disruptors in the sludge are removed, and modified activated carbon (whose surface mainly contains acidic functional groups and basic functional groups) is obtained. After the treated sludge-activated carbon is dehydrated and separated, it is directly dried to obtain regenerated activated carbon with strong adsorption capacity. The regenerated activated carbon is directly recycled to the activated sludge biochemical pool with activated carbon added, or used to adsorb low-concentration malodorous gas. The adsorbed activated carbon enters the activated sludge biochemical pool with activated carbon added for co-treatment and regeneration. Among them, the inorganic demulsifier is sodium silicate and / or calcium chloride, and the dosage is 0.01 - 1.5 g / L. The slow-release oxidant is an oxidant such as calcium peroxide, magnesium peroxide, or sodium hypochlorite, and the dosage is 0.5 - 5 g / L. The reaction time is 6 - 24 h. The dehydration and separation is centrifugation, the centrifugal speed is 1000 - 5000 rmp, the drying temperature is 55 - 95 °C at low temperature, and the drying time is 4 - 12 h.

[0031] The present invention also provides a co-treatment system for malodorous gas and wastewater, which is used to implement the above co-treatment method for malodorous gas and wastewater. The co-treatment system includes: a malodorous gas adsorption device, a malodorous gas enrichment pipeline, a multi-airway mixing and output device, an activated carbon dosing system, a co-degradation biochemical pool, a sludge-activated carbon oxidation and regeneration device, and a sludge-activated carbon dehydration and drying device.

[0032] Among them, the outlet of the malodorous gas adsorption device is connected to the inlet of the malodorous gas enrichment pipeline, and the outlet of the malodorous gas enrichment pipeline is connected to the malodorous gas inlet of the co-degradation biochemical pool. The outlet of the activated carbon dosing system is connected to the activated carbon inlet of the co-degradation biochemical pool. The co-degradation biochemical pool is also provided with a water outlet and a sludge discharge port. The sludge discharge port is connected to the inlet of the sludge-activated carbon oxidation and regeneration device, and the outlet of the sludge-activated carbon oxidation and regeneration device is connected to the sludge-activated carbon dehydration and drying device.

[0033] In the above-mentioned collaborative treatment system for malodorous gas and wastewater, preferably, the collaborative degradation biochemical tank and / or the sludge activated carbon dehydration and drying device are respectively further provided with malodorous gas outlets, and the malodorous gas outlets are connected to the inlets of the malodorous gas adsorption device.

[0034] In the above-mentioned collaborative treatment system for malodorous gas and wastewater, preferably, the sludge activated carbon dehydration and drying device is provided with a sludge discharge outlet, and the sludge discharge outlet of the sludge activated carbon dehydration and drying device is connected to the activated carbon inlet of the collaborative degradation biochemical tank.

[0035] In the above-mentioned collaborative treatment system for malodorous gas and wastewater, preferably, the malodorous gas adsorption device is filled with activated carbon. In the collaborative treatment system for malodorous gas and wastewater of the present invention, the malodorous gas adsorption device adsorbs low-concentration malodorous gas through activated carbon, and the malodorous gas comes from sewage treatment plants, production devices, etc.; when activated carbon adsorption is not adopted, the malodorous gas can directly enter the malodorous gas enrichment pipeline. The malodorous gas enrichment pipeline can receive the discharged gas from the malodorous gas adsorption device, or can directly receive the malodorous gas from sewage treatment plants, production devices, etc.

[0036] In the above-mentioned collaborative treatment system for malodorous gas and wastewater, preferably, the multi-gas-path mixing and output device includes a gas pipeline, a cavity, a sealing piece, and a bolt, and is provided with at least two inlets and one outlet to realize multi-gas-path gas mixing and output; a flow meter is provided in front of each inlet to adjust the flow ratio of each gas path.

[0037] In the above-mentioned collaborative treatment system for malodorous gas and wastewater, preferably, the sludge activated carbon oxidation and regeneration device includes a reaction kettle, a chemical agent adding port, and a stirring paddle; the sludge activated carbon dehydration and drying device includes a centrifuge and a dryer.

[0038] The technical solution provided by the present invention has the following beneficial effects:

[0039] The present invention organically combines the treatment of malodorous gas with the biochemical treatment of wastewater in a sewage treatment plant, realizes the collaborative control of waste gas and wastewater pollution, avoids the repeated construction of a malodorous pollution treatment system, and at the same time supplements the carbon source of the biological treatment unit; the activated carbon regeneration process is simple, has low energy consumption, no environmental pollution risk, and the resource utilization of the regenerated activated carbon reduces the dosage of fresh activated carbon, and is applicable to the engineering application of the collaborative treatment of malodorous gas and wastewater in the petroleum and petrochemical industries. Description of the Drawings

[0040] Figure 1 It is a schematic flow chart of the collaborative treatment system for malodorous gas and wastewater in Example 1. Detailed Embodiments

[0041] For a clearer understanding of the technical features, objectives, and beneficial effects of the present invention, the following detailed description of the technical solution of the present invention is provided, but it should not be construed as a limitation on the scope of implementation of the present invention.

[0042] Example 1

[0043] This example provides a synergistic treatment system for malodorous gas and wastewater. As Figure 1 shown, it includes: a malodorous gas adsorption device, a malodorous gas enrichment pipeline, a multi-gas-path mixing and output device, an activated carbon dosing system, a synergistic degradation biochemical pool, a sludge-activated carbon oxidation and regeneration device, and a sludge-activated carbon dehydration and drying device;

[0044] Among them, the outlet of the malodorous gas adsorption device is connected to the inlet of the malodorous gas enrichment pipeline, and the outlet of the malodorous gas enrichment pipeline is connected to the malodorous gas inlet of the synergistic degradation biochemical pool; the outlet of the activated carbon dosing system is connected to the activated carbon inlet of the synergistic degradation biochemical pool. The synergistic degradation biochemical pool also has a water outlet and a sludge discharge outlet. The sludge discharge outlet is connected to the inlet of the sludge-activated carbon oxidation and regeneration device, and the outlet of the sludge-activated carbon oxidation and regeneration device is connected to the sludge-activated carbon dehydration and drying device; the synergistic degradation biochemical pool and / or the sludge-activated carbon dehydration and drying device are also respectively provided with malodorous gas outlets, and the malodorous gas outlets are connected to the inlet of the malodorous gas adsorption device; the sludge-activated carbon dehydration and drying device is provided with a sludge discharge outlet, and the sludge discharge outlet of the sludge-activated carbon dehydration and drying device is connected to the activated carbon inlet of the synergistic degradation biochemical pool.

[0045] Example 2

[0046] This example provides a synergistic treatment method for malodorous gas and wastewater, which is implemented using the synergistic treatment system for malodorous gas and wastewater in Example 1. The malodorous gas is the malodorous gas in the flotation tank of refinery wastewater, and its main components include: ammonia is 50 mg / m 3 , hydrogen sulfide is 25 mg / m 3 , total non-methane hydrocarbons are 400 mg / m 3 , aromatic hydrocarbons are 100 mg / m 3 , and organic sulfur compounds are 80 mg / m 3 . This treatment method includes the following steps:

[0047] S1. Mix the malodorous gas and air in a volume ratio (flow ratio) of 1:3 to obtain a mixed gas;

[0048] S2. Send the wastewater (COD is 250 mg / L) into the biochemical pool, add activated carbon (dosage 0.1 g / L) into the biochemical pool, and then aerate the mixed gas into the biochemical pool to carry out a biochemical reaction; among them, the temperature of the wastewater in the biochemical pool is 25 °C, the diameter of the aeration bubbles is 1 mm, and the dissolved oxygen concentration of the wastewater in the biochemical pool is 0.9 mg / L;

[0049] S3. After the reaction is completed, the sludge in the biochemical pool is discharged, calcium peroxide (dosage: 1 g / L) and calcium chloride (dosage: 1 g / L) are added to the sludge, and an oxidation reaction is carried out at 50 °C for 12 h; after the reaction is completed, centrifugal dehydration is carried out at a speed of 3000 rmp, and then drying is carried out at 65 °C for 6 h to obtain regenerated activated carbon.

[0050] After testing, the specific surface area of this regenerated activated carbon is 530 m 2 / g, the average pore diameter is 4.2 nm, and it can be added to the biochemical pool to replace commercial activated carbon.

[0051] Example 3

[0052] This example provides a method for co-treatment of malodorous gas and wastewater, which is the same as Example 2, except that: the volume ratio of malodorous gas to air is 1:10, and the dissolved oxygen concentration of the wastewater is 1.8 mg / L.

[0053] Example 4

[0054] This example provides a method for co-treatment of malodorous gas and wastewater, which is the same as Example 2, except that: the volume ratio of malodorous gas to air is 1:15, and the dissolved oxygen concentration of the wastewater is 3 mg / L.

[0055] Example 5

[0056] This example provides a method for co-treatment of malodorous gas and wastewater, which is the same as Example 2, except that: the diameter of the aeration bubbles is 2 mm, and the dissolved oxygen concentration of the wastewater is 0.7 mg / L.

[0057] Example 6

[0058] This example provides a method for co-treatment of malodorous gas and wastewater, which is the same as Example 3, except that: the diameter of the aeration bubbles is 2 mm, and the dissolved oxygen concentration of the wastewater is 1.6 mg / L.

[0059] Example 7

[0060] This example provides a method for co-treatment of malodorous gas and wastewater, which is the same as Example 4, except that: the diameter of the aeration bubbles is 2 mm, and the dissolved oxygen concentration of the wastewater is 2.5 mg / L.

[0061] Example 8

[0062] This example provides a method for co-treatment of malodorous gas and wastewater, which is the same as Example 2, except that: the diameter of the aeration bubbles is 3 mm, and the dissolved oxygen concentration of the wastewater is 0.5 mg / L.

[0063] Example 9

[0064] This embodiment provides a method for co - treating malodorous gas and wastewater, which is the same as Embodiment 3, except that: the diameter of the aeration bubbles is 3 mm, and the dissolved oxygen concentration of the wastewater is 1.3 mg / L.

[0065] Embodiment 10

[0066] This embodiment provides a method for co - treating malodorous gas and wastewater, which is the same as Embodiment 4, except that: the diameter of the aeration bubbles is 3 mm, and the dissolved oxygen concentration of the wastewater is 2 mg / L.

[0067] Embodiment 11

[0068] This embodiment provides a method for co - treating malodorous gas and wastewater, which is the same as Embodiment 2, except that: the volume ratio of malodorous gas to air is 1:5, the diameter of the aeration bubbles is 2 mm, and the dissolved oxygen concentration of the wastewater is 1.5 mg / L.

[0069] The COD of the effluent from the biochemical tanks of the above - mentioned Embodiments 2 - 11 was tested, and the results are shown in Table 1.

[0070] Table 1 Biochemical conditions and wastewater treatment results

[0071]

[0072]

[0073] It can be seen from Embodiments 2 - 11 that when the malodorous gas from the flotation tank of refinery wastewater and the wastewater are co - treated in the biochemical tank, the removal rate of COD in the wastewater is 70 - 82%; it can be seen from Embodiments 2 - 4, Embodiments 5 - 7, and Embodiments 8 - 10 respectively that when the bubble diameter is the same, the larger the proportion of air in the mixed gas, the higher the dissolved oxygen concentration, and the lower the effluent COD; as the bubble diameter increases, the dissolved oxygen concentration decreases, and the effluent COD also increases. It can be seen from Embodiments 10 and 11 that increasing the proportion of malodorous gas in the mixed gas and at the same time reducing the bubble diameter can also obtain a higher COD removal rate under a lower dissolved oxygen condition.

[0074] Comparative Example 1

[0075] This comparative example provides a method for co - treating malodorous gas and wastewater, which is the same as Embodiment 2, except that: no malodorous gas is mixed in, and the dissolved oxygen concentration of the wastewater is 2 mg / L.

[0076] Comparative Example 2

[0077] This comparative example provides a method for co - treating malodorous gas and wastewater, which is the same as Embodiment 8, except that: no malodorous gas is mixed in, and the dissolved oxygen concentration of the wastewater is 1.5 mg / L.

[0078] The COD of the effluent from the biochemical pool in Comparative Examples 1-2 above was tested, and the results are shown in Table 2.

[0079] Table 2 Biochemical Conditions and Wastewater Treatment Results

[0080]

[0081] Comparative Examples 1 and 2 are the effects of not transporting the malodorous gas to the biochemical pool. The results show that when the malodorous gas is not mixed, the COD of the effluent from the biochemical unit is slightly higher than the average effluent COD concentration when the malodorous gas is mixed. Considering Examples 2-11 and Comparative Examples 1-2 comprehensively, the addition of the malodorous gas not only does not affect the treatment effect of the original biochemical unit, but also can reduce the malodorous gas while ensuring the effluent from the biochemical unit.

[0082] The following examples and comparative examples are used to investigate the dosage of activated carbon, including the use of regenerated activated carbon.

[0083] Example 12

[0084] This example provides a method for co-treatment of malodorous gas and wastewater, which is implemented using the co-treatment system for malodorous gas and wastewater in Example 1. The malodorous gas is the malodorous gas from the flotation tank of refinery wastewater, and its main components include: ammonia is 60 mg / m 3 , hydrogen sulfide is 30 mg / m 3 , total non-methane hydrocarbons is 450 mg / m 3 , aromatic hydrocarbons is 150 mg / m 3 , and organic sulfur compounds is 120 mg / m 3 . The treatment method includes the following steps:

[0085] S1. Mix the malodorous gas and air at a volume ratio (flow ratio) of 1:5 to obtain a mixed gas;

[0086] S2. Feed the wastewater (COD is 200 mg / L) into the biochemical pool, add activated carbon (dosage 0.05 g / L) into the biochemical pool, and then aerate the mixed gas into the biochemical pool to carry out the biochemical reaction; among them, the temperature of the wastewater in the biochemical pool is 25 °C, the diameter of the aeration bubbles is 2 mm, and the dissolved oxygen concentration of the wastewater in the biochemical pool is 1.5 mg / L;

[0087] S3. The same as Example 2.

[0088] Results: The COD removal rate of the wastewater is 70%, and in the malodorous gas collected from the biochemical pool, ammonia is 3 mg / m 3 , hydrogen sulfide is 0.5 mg / m 3 , total non-methane hydrocarbons is 100 mg / m 3 , and aromatic hydrocarbons is 30 mg / m 3, the organic sulfur compound is 5 mg / m 3 .

[0089] Example 13

[0090] This example provides a method for the co-treatment of malodorous gas and wastewater, which is the same as Example 12, except that the dosage of activated carbon is 0.2 g / L.

[0091] Result: The COD removal rate of the wastewater is 80%, and in the malodorous gas collected from the biochemical tank, ammonia is 0.5 mg / m 3 , hydrogen sulfide is 0.2 mg / m 3 , non-methane total hydrocarbons are 40 mg / m 3 , aromatic hydrocarbons are 12 mg / m 3 , organic sulfur compounds are 0.9 mg / m 3 .

[0092] Example 14

[0093] This example provides a method for the co-treatment of malodorous gas and wastewater, which is the same as Example 12, except that the dosage of activated carbon is 0.4 g / L.

[0094] Result: The COD removal rate of the wastewater is 88%, and in the malodorous gas collected from the biochemical tank, ammonia is 0.3 mg / m 3 , hydrogen sulfide is 0.08 mg / m 3 , non-methane total hydrocarbons are 30 mg / m 3 , aromatic hydrocarbons are 10 mg / m 3 , organic sulfur compounds are 0.8 mg / m 3 .

[0095] Example 15

[0096] This example provides a method for the co-treatment of malodorous gas and wastewater, which is the same as Example 12, except that the added activated carbon is a combination of 0.2 g / L of commercially available activated carbon and 0.2 g / L of the regenerated activated carbon of Example 2.

[0097] Result: The COD removal rate of the wastewater is 84%, and in the malodorous gas collected from the biochemical tank, ammonia is 0.5 mg / m 3 , hydrogen sulfide is 0.2 mg / m 3 , non-methane total hydrocarbons are 40 mg / m 3 , aromatic hydrocarbons are 12 mg / m 3 , organic sulfur compounds are 0.9 mg / m 3 .

[0098] Comparative Example 3

[0099] This comparative example provides a method for the co-treatment of malodorous gas and wastewater, which is the same as Example 12, except that the dosage of activated carbon is 0.

[0100] Result: The COD removal rate of the wastewater is 40%, and the ammonia in the malodorous gas collected from the biochemical tank is 9 mg / m 3 、hydrogen sulfide is 5 mg / m 3 、non-methane total hydrocarbons are 180 mg / m 3 、aromatic hydrocarbons are 60 mg / m 3 、organic sulfur compounds are 50 mg / m 3 。

[0101] Comparative Example 4

[0102] This comparative example provides a method for the co-treatment of malodorous gas and wastewater, which is the same as Example 12, except that the dosage of activated carbon is 0.5 g / L.

[0103] Result: The COD removal rate of the wastewater is 88%, and the ammonia in the malodorous gas collected from the biochemical tank is 0.3 mg / m 3 、hydrogen sulfide is 0.08 mg / m 3 、non-methane total hydrocarbons are 28 mg / m 3 、aromatic hydrocarbons are 10 mg / m 3 、organic sulfur compounds are 0.7 mg / m 3 。

[0104] For the above Examples 12 - 15 and Comparative Examples 3 - 4, the COD removal rate of the wastewater and the concentration of malodorous substances in the gas collected from the biochemical tank were detected, and the results are shown in Table 3.

[0105] Table 3 Dosage of activated carbon and components of treated malodorous gas

[0106]

[0107] Summary: Comparing Example 12 and Comparative Example 3, when there is no activated carbon, the removal rates of COD and malodorous gas concentration are not high; when 0.05 g / L of activated carbon is added, the removal rates of COD and malodorous gas increase significantly, reflecting the co-treatment of malodorous gas and wastewater. From Examples 12 - 15, as the dosage of activated carbon increases, the removal efficiency of COD and malodorous gas increases. However, comparing Example 14 and Comparative Example 4 shows that when the activated carbon increases from 0.4 g / L to 0.5 g / L, the removal efficiency of COD and malodorous gas remains basically unchanged. Therefore, the dosage of activated carbon can be 0.05 - 0.4 g / L. From Examples 14 and 15, it can be seen that using the same amount of regenerated activated carbon is beneficial to the removal of COD and malodorous gas.

[0108] The following examples and comparative examples are used to investigate the temperature of the biochemical tank.

[0109] Example 16

[0110] This example provides a method for co - treating malodorous gas and wastewater, which is implemented using the co - treatment system for malodorous gas and wastewater in Example 1. The malodorous gas is the malodorous gas from the flotation tank of refinery wastewater, and its main components include: ammonia is 60 mg / m 3 , hydrogen sulfide is 30 mg / m 3 , total non - methane hydrocarbons are 450 mg / m 3 , aromatic hydrocarbons are 150 mg / m 3 , organosulfur compounds are 120 mg / m 3 . The treatment method includes the following steps:

[0111] S1. Mix the malodorous gas and air in a volume ratio (flow ratio) of 1:5 to obtain a mixed gas;

[0112] S2. Feed the wastewater (COD is 200 mg / L) into the biochemical pool, add the activated carbon regenerated in Example 2 (dosage 0.2 g / L) into the biochemical pool, and then aerate the mixed gas into the biochemical pool to carry out the biochemical reaction; among them, the temperature of the wastewater in the biochemical pool is 25 °C, the diameter of the aeration bubbles is 2 mm, and the dissolved oxygen concentration of the wastewater in the biochemical pool is 1.5 mg / L;

[0113] S3. The same as Example 2.

[0114] Result: The COD removal rate of the wastewater is 87%, and in the malodorous gas collected from the biochemical pool, ammonia is 0.3 mg / m 3 , hydrogen sulfide is 0.08 mg / m 3 , total non - methane hydrocarbons are 26 mg / m 3 , aromatic hydrocarbons are 10 mg / m 3 , organosulfur compounds are 0.8 mg / m 3 .

[0115] Example 17

[0116] This example provides a method for co - treating malodorous gas and wastewater, which is the same as Example 16, except that the temperature of the biochemical pool is 38 °C.

[0117] Result: The COD removal rate of the wastewater is 88%, and in the malodorous gas collected from the biochemical pool, ammonia is 0.3 mg / m 3 , hydrogen sulfide is 0.08 mg / m 3 , total non - methane hydrocarbons are 27 mg / m 3 , aromatic hydrocarbons are 10 mg / m 3 , organosulfur compounds are 0.8 mg / m 3 .

[0118] Comparative Example 5

[0119] This comparative example provides a method for the co-treatment of malodorous gas and wastewater, which is the same as Example 16, except that the temperature of the biochemical pool is 20 °C.

[0120] Result: The COD removal rate of the wastewater is 75%, and the ammonia in the malodorous gas collected from the biochemical pool is 0.9 mg / m 3 , the hydrogen sulfide is 0.4 mg / m 3 , the non-methane total hydrocarbons are 50 mg / m 3 , the aromatic hydrocarbons are 20 mg / m 3 , the organic sulfur compounds are 2.9 mg / m 3 .

[0121] Comparative Example 6

[0122] This comparative example provides a method for the co-treatment of malodorous gas and wastewater, which is the same as Example 16, except that the temperature of the biochemical pool is 40 °C.

[0123] Result: The COD removal rate of the wastewater is 80%, and the ammonia in the malodorous gas collected from the biochemical pool is 2.9 mg / m 3 , the hydrogen sulfide is 1.2 mg / m 3 , the non-methane total hydrocarbons are 45 mg / m 3 , the aromatic hydrocarbons are 22 mg / m 3 , the organic sulfur compounds are 2.5 mg / m 3 .

[0124] For the above Examples 16-17 and Comparative Examples 5-6, the COD removal rate of the wastewater and the concentration of malodorous substances in the gas collected from the biochemical pool were detected, and the results are shown in Table 4.

[0125] Table 4 Temperature of the biochemical pool and composition of the treated malodorous gas

[0126]

[0127] Summary: When the temperature of the biochemical pool is 20 °C, the removal of COD and malodorous gas is not good. When the temperature is increased to 25 °C and 38 °C, the COD treatment is higher than 87%, and the concentration of the malodorous gas collected from the biochemical pool is low. However, when the temperature of the biochemical pool is 40 °C, the co-removal effect of COD and malodorous gas becomes worse. Therefore, the temperature of the biochemical pool can be 25-38 °C.

Claims

1. A method for co - treating malodorous gas and wastewater, which comprises the following steps: S1. Mix the malodorous gas and air according to a volume ratio of 1:3 - 15 to obtain a mixed gas; S2. Feed the wastewater into the biochemical pool, add activated carbon into the biochemical pool, and then aerate the mixed gas into the biochemical pool for biochemical reaction; wherein, The diameter of the aeration bubbles is 1 - 3 mm, and the dissolved oxygen concentration of the wastewater in the biochemical pool is 0.5 - 3 mg / L; S3. After the reaction ends, discharge the sludge in the biochemical pool and treat it to regenerate the activated carbon in the sludge.

2. The co-treatment method for malodorous gas and wastewater according to claim 1, wherein, The components of the malodorous gas include: ammonia 40 - 60 mg / m 3 , hydrogen sulfide 20 - 30 mg / m 3 , total non-methane hydrocarbons 350 - 450 mg / m 3 , aromatic hydrocarbons 50 - 150 mg / m 3 , organic sulfur compounds 30 - 120 mg / m 3 ; Preferably, the malodorous gas is the malodorous gas from the flotation tank of refinery wastewater.

3. The co-treatment method of malodorous gas and wastewater according to claim 1, wherein, The COD of the wastewater entering the biochemical pool is 100 - 250 mg / L.

4. The co-treatment method for malodorous gas and wastewater according to claim 1, wherein, Based on the volume of the wastewater in the biochemical pool, the dosage of activated carbon is 0.05 - 0.4 g / L.

5. The co-treatment method of malodorous gas and wastewater according to claim 1, wherein, During the biochemical reaction, the temperature of the wastewater in the biochemical pool is 25 - 38 °C.

6. The co-treatment method for malodorous gas and wastewater according to claim 1, wherein, The method for treating the sludge in S3 includes: adding an inorganic demulsifier to the sludge, then adding a slow - release oxidant for an oxidation reaction, followed by dehydration separation and drying to obtain regenerated activated carbon.

7. The co-treatment method of malodorous gas and wastewater according to claim 6, wherein, Based on the total mass of the sludge, the dosage of the inorganic demulsifier is 0.01 - 1.5 g / L; Preferably, the inorganic demulsifier includes sodium silicate and / or calcium chloride.

8. The co-treatment method of malodorous gas and wastewater according to claim 6, wherein, Based on the total mass of the sludge, the dosage of the slow - release oxidant is 0.5 - 5 g / L; Preferably, the slow - release oxidant includes at least one of calcium peroxide, magnesium peroxide, and sodium hypochlorite; Preferably, the oxidation reaction temperature is 40 - 80 °C and the time is 6 - 24 h.

9. The co-treatment method of malodorous gas and wastewater according to claim 6, wherein, The way of dehydration separation is centrifugation, and the centrifugation speed is 1000 - 5000 rmp; Preferably, the drying temperature is 55 - 95 °C and the time is 4 - 12 h.

10. A co-treatment system for malodorous gas and wastewater, which is used to implement the co-treatment method for malodorous gas and wastewater according to any one of claims 1-9, the co-treatment system comprising: Malodorous gas adsorption device, malodorous gas enrichment pipeline, multi - gas - path mixing and output device, activated carbon dosing system, co - degradation biochemical pool, sludge activated carbon oxidation and regeneration device, sludge activated carbon dehydration and drying device; Among them, the outlet of the malodorous gas adsorption device is connected to the inlet of the malodorous gas enrichment pipeline, and the outlet of the malodorous gas enrichment pipeline is connected to the malodorous gas inlet of the co - degradation biochemical pool; the outlet of the activated carbon dosing system is connected to the activated carbon inlet of the co - degradation biochemical pool. The co - degradation biochemical pool is also provided with a water outlet and a sludge discharge port. The sludge discharge port is connected to the inlet of the sludge activated carbon oxidation and regeneration device, and the outlet of the sludge activated carbon oxidation and regeneration device is connected to the sludge activated carbon dehydration and drying device.

11. The co-treatment system for malodorous gas and wastewater according to claim 10, wherein, The co - degradation biochemical pool and / or the sludge activated carbon dehydration and drying device are also respectively provided with malodorous gas outlets, and the malodorous gas outlets are connected to the inlet of the malodorous gas adsorption device.

12. The co-treatment system for malodorous gas and wastewater according to claim 10, wherein, The sludge activated carbon dehydration and drying device is provided with a sludge discharge port, and the sludge discharge port of the sludge activated carbon dehydration and drying device is connected to the activated carbon inlet of the co - degradation biochemical pool.

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