Formamide wastewater treatment device

Abstract

According to the formamide wastewater treatment device, wastewater and alkali liquor supplied by the alkali metering pump are mixed through the mixing tank, the wastewater is alkalized, then the alkalized wastewater is input into the hydrolysis reactor, formamide in the wastewater is hydrolyzed into formate and ammonia gas, then the hydrolyzed wastewater is transferred into the aeration tank, and the aeration tank is used for aeration treatment of the formamide wastewater. Ammonia gas is separated from the wastewater by aerating air supplied by the first fan, the separated ammonia gas and the air enter the absorption tower together, the ammonia gas is absorbed by using clear water to obtain ammonia water, and the aerated wastewater is conveyed into the microbial decomposition system to be subjected to biochemical treatment for further purification. According to the device, the formamide wastewater is treated through cooperative use of the equipment, the defect that energy consumption is large when the formamide wastewater is treated in a traditional distillation separation mode can be effectively overcome, ammonia water is produced as a byproduct in the treatment process, and the advantage of resource utilization of the wastewater is further achieved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of organic wastewater treatment, in particular to a formamide wastewater treatment device. BACKGROUND

[0002] As an amide product, formamide has strong solubility and active reactivity, can be used as a raw material for organic synthesis, a softener for fiber industry, a treatment agent for paper and a softener for animal glue, and can also be used as an analysis reagent for determining the amino acid content in rice. In terms of organic synthesis, formamide has more uses in medicine, and also has many uses in dyes, pesticides, spices, pigments and auxiliaries. After formamide is used as a reaction substrate or a solvent in industrial synthesis, the formamide and other organic matters contained in the generated wastewater result in a high COD value of the wastewater, so the wastewater must be treated before being discharged. Traditional treatment methods such as extraction method, distillation / rectification method and the like have the problems of large energy consumption, difficulty in achieving the effect due to the mutual solubility of formamide and water, and large energy consumption due to heating. CONTENT OF THE UTILITY MODEL

[0003] The application provides a formamide wastewater treatment device to solve the problem of large energy consumption in treating formamide wastewater by using a traditional distillation separation method.

[0004] The application provides a formamide wastewater treatment device, which comprises a mixing tank, a hydrolysis reactor, an aeration tank and a microbial decomposition system connected in sequence.

[0005] The mixing tank is further connected with a formamide wastewater pipeline and an alkali metering pump respectively.

[0006] The aeration tank is further connected with a first fan and an absorption tower respectively.

[0007] Optionally, the microbial decomposition system comprises an anaerobic tank, an anoxic tank, an aerobic tank, a secondary sedimentation tank, an oxidation tank and a reuse water tank connected in sequence.

[0008] The anaerobic tank, the anoxic tank and the aerobic tank are each provided with heat exchange pipes, and each heat exchange pipe is connected with a constant-temperature water tank to form a loop.

[0009] The constant-temperature water tank is connected with a heat exchange water tank to form a loop, and the heat exchange water tank is connected with a solar heat collector to form a loop.

[0010] Optionally, the constant-temperature water tank is further connected with a gas-fired boiler to form a loop.

[0011] Optionally, the anaerobic tank, the anoxic tank and the aerobic tank are respectively provided with a first gas collecting hood, a second gas collecting hood and a third gas collecting hood.

[0012] The first and second gas collection hoods are connected to the gas boiler via a second fan, and the third gas collection hood is also connected to the gas boiler.

[0013] Optionally, the hydrolysis reactor includes a shell, and a reaction tube is disposed inside the shell;

[0014] The reaction tube is coiled and folded into multiple layers inside the shell;

[0015] The input end of the reaction tube passes through the lower part of the side of the housing and extends out of the housing; the input end of the reaction tube passes through the upper part of the side of the housing and extends out of the housing.

[0016] The shell is connected to the constant temperature water tank to form a loop.

[0017] Optionally, multiple porous plates are arranged in an array inside the reaction tube, each porous plate being arranged perpendicular to the axis of the reaction tube.

[0018] Optionally, an electrolysis tank is also provided between the aeration tank and the microbial decomposition system.

[0019] The formamide wastewater treatment device of this application mixes wastewater with alkali solution supplied by an alkali metering pump in a mixing tank to alkali the wastewater. The alkali-treated wastewater is then fed into a hydrolysis reactor, where formamide is hydrolyzed into formate and ammonia. The hydrolyzed wastewater is then transferred to an aeration tank, where air supplied by a first blower aerates and separates the ammonia from the wastewater. The separated ammonia, along with the air, enters an absorption tower where it is absorbed by clean water to obtain ammonia water. The aerated wastewater is then transported to a microbial decomposition system for further biochemical treatment and purification. This device, through the combined use of the above equipment, effectively overcomes the high energy consumption of traditional distillation methods for treating formamide wastewater. Furthermore, the ammonia water produced as a byproduct during the treatment process also demonstrates the resource utilization of the wastewater. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of a formamide wastewater treatment device provided in one embodiment of this application;

[0022] Figure 2 A schematic diagram of a formamide wastewater treatment device provided in another embodiment of this application;

[0023] Figure 3A schematic diagram of a formamide wastewater treatment device according to another embodiment of the present application is provided.

[0024] Figure 4 A structural schematic diagram of a hydrolysis reactor according to an embodiment of the present application is provided.

[0025] Figure 5 A structural schematic diagram of a reaction tube according to an embodiment of the present application is provided.

[0026] Figure 6 A schematic diagram of a formamide wastewater treatment device according to another embodiment of the present application is provided.

[0027] Legend of reference signs:

[0028] 1, mixing tank; 2, hydrolysis reactor; 3, aeration tank; 4, microbial decomposition system; 5, absorption tower; 6, electrolytic cell; 10, formamide wastewater pipeline; 20, alkali metering pump; 21, shell; 22, reaction tube; 30, first fan; 40, second fan; 41, anaerobic tank; 42, anoxic tank; 43, aerobic tank; 44, secondary sedimentation tank; 45, constant-temperature water tank; 46, heat exchange water tank; 47, solar heat collector; 48, gas boiler; 221, perforated plate; 411, heat exchange pipe; 421, first gas collection hood; 422, second gas collection hood; 423, third gas collection hood; 441, oxidation tank; 442, recycled water tank. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are some embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor also belong to the scope of protection of the present application.

[0030] As shown in Figure 1 the present application provides a formamide wastewater treatment device, which comprises a mixing tank 1, a hydrolysis reactor 2, an aeration tank 3 and a microbial decomposition system 4 connected in series.

[0031] The mixing tank 1 is further connected with a formamide wastewater pipeline 10 and an alkali metering pump 20 respectively.

[0032] The aeration tank 3 is further connected with a first fan 30 and an absorption tower 5 respectively.

[0033] In use, the formamide-containing wastewater delivered by the formamide wastewater pipeline 10 is added to the mixing tank 1, while the alkali metering pump 20 pours the alkali liquid into the mixing tank 1 according to a preset proportion, mixes with the formamide wastewater, adjusts the pH value of the formamide wastewater to alkaline (for example, 8-10), and obtains the alkalized wastewater. The alkalized wastewater is then delivered to the hydrolysis reactor 2 for reaction, and the formamide in the wastewater is hydrolyzed into formic acid and ammonia gas. The wastewater after the hydrolysis reaction in the hydrolysis reactor 2 (at this time, the formamide in the wastewater is hydrolyzed into formate and ammonia gas) is introduced into the aeration tank 3. The first fan 30 is used to introduce compressed air into the aeration tank 3. The ammonia gas in the wastewater is discharged through air stripping and aeration (and at this time, the water temperature is relatively high, about 35°C, which is also conducive to the escape of ammonia gas). The discharged ammonia gas and compressed air are collected (the gas discharged from the aeration tank 3 can be collected by adding a collection cover above the aeration tank 3), and then transferred into the absorption tower 5 (for example, a spray tower). The ammonia gas in the absorption tower 5 is absorbed by clean water, and then discharged. The ammonia water obtained after absorption can also be used in other ammoniation sections of the factory.

[0034] The wastewater after aeration stripping is transferred into the microbial decomposition system 4 for biochemical treatment, so that the organic matter in the wastewater is deeply treated, and the wastewater is purified.

[0035] The formamide wastewater treatment device provided by the present application mixes the wastewater with the alkali liquid supplied by the alkali metering pump 20 in the mixing tank 1, alkalizes the wastewater, inputs the alkalized wastewater into the hydrolysis reactor 2, hydrolyzes the formamide in the wastewater into formate and ammonia gas, transfers the wastewater after hydrolysis into the aeration tank 3, separates the ammonia gas from the wastewater through aeration by the air supplied by the first fan 30, introduces the separated ammonia gas into the absorption tower 5 together with the air, absorbs the ammonia gas by clean water to obtain ammonia water, and then delivers the wastewater after aeration to the microbial decomposition system 4 for biochemical treatment for further purification. The device is used in cooperation with the above-mentioned equipment to treat the formamide wastewater, effectively solves the problems of environmental pollution and waste of water resources caused by the discharge of formamide wastewater, and has the characteristics of resource utilization of wastewater in the treatment process.

[0036] As shown in FIGS. Figure 2 and Figure 3 Optionally, the microbial decomposition system 4 includes an anaerobic tank 41, an anoxic tank 42, an aerobic tank 43, a secondary sedimentation tank 44, an oxidation tank 441 and a reuse water tank 442 connected in sequence;

[0037] The heat exchange pipes 411 are arranged in the anaerobic tank 41, the anoxic tank 42 and the aerobic tank 43, respectively, and each heat exchange pipe 411 is connected with the constant-temperature water tank 45 to form a loop.

[0038] The constant-temperature water tank 45 is connected with the heat exchange water tank 46 into a loop, and the heat exchange water tank 46 is connected with the solar heat collector 47 into a loop.

[0039] In the present application, when biochemical treatment is carried out in the microbial decomposition system 4, the wastewater is first delivered to the anaerobic tank 41 to carry out anaerobic fermentation treatment on the wastewater by using activated sludge containing anaerobic bacteria. After the wastewater is subjected to anaerobic fermentation treatment for a period of time, it is transferred to the anoxic tank 42 to carry out anoxic fermentation treatment. After the anoxic fermentation treatment is completed, the wastewater is delivered to the aerobic tank 43 to carry out aerobic fermentation (air is continuously blown into the aerobic tank 43 by using an air supply device during aerobic fermentation) so as to facilitate the smooth progress of the aerobic fermentation process. After the aerobic fermentation is completed, the treated wastewater is transferred to the secondary sedimentation tank 44 to carry out sedimentation, and the activated sludge therein is separated from the water. The separated activated sludge can be recycled back to the aerobic tank 43, and the separated water, i.e. supernatant, is transferred to the oxidation tank 441 to be oxidized by using an oxidizing agent (ozone is used in the present application), and then is collected in the reclaimed water tank 442, which can be used in a section with low requirements on water quality. Alternatively, the water in the reclaimed water tank can be delivered to a deep purification section such as ultrafiltration, reverse osmosis, etc. for further treatment to meet the water requirements. During the above-mentioned anaerobic, anoxic and aerobic fermentation processes, since the microorganisms are sensitive to temperature, the fermentation temperature needs to be maintained within a relatively stable range. In order to avoid the fermentation temperature being too low in some cold seasons to affect the fermentation process of the microorganisms, heat exchange pipes 411 are laid in the above-mentioned anaerobic tank 41, anoxic tank 42 and aerobic tank 43, and hot water (40℃±2℃) of a suitable temperature is supplied by the constant-temperature water tank 45 to carry out heat exchange with the fermentation tanks so as to maintain the constant fermentation temperature. The constant temperature of the water in the constant-temperature water tank 45 is achieved by heat exchange with the heat exchange water tank 46, and the heat source of the heat exchange water tank 46 comes from the solar heat collector 47. During sunny days or other time periods with sufficient light, the solar heat collector 47 can mainly provide heat exchange medium for the heat exchange water tank 46 to reduce the treatment cost.

[0040] As shown in Figure 3 Optionally, the constant-temperature water tank 45 is also connected with the gas-fired boiler 48 into a loop.

[0041] As shown in Figure 3 Optionally, the anaerobic tank 41, anoxic tank 42 and aerobic tank 43 are respectively provided with a first gas collecting hood 421, a second gas collecting hood 422 and a third gas collecting hood 423.

[0042] The first gas collecting hood 421 and the second gas collecting hood 422 are connected with the gas-fired boiler 48 through the second fan 40, and the third gas collecting hood 423 is connected with the gas-fired boiler 48.

[0043] In this application, the heat sources for the hot water exchange tank 46 are a gas-fired boiler 48 and a solar collector 47. On sunny days or when there is sufficient sunlight, the solar collector 47 can mainly provide the heat exchange medium for the hot water exchange tank 46, while the gas-fired boiler 48 is on standby to reduce the fuel consumption of the gas-fired boiler 48 and lower the processing cost. In cold seasons or during periods of insufficient sunlight, the gas-fired boiler 48 can mainly provide the heat exchange medium for the hot water exchange tank 46 to maintain stable heat exchange to each fermentation tank and ensure the smooth progress of the biochemical treatment process.

[0044] Meanwhile, during the anaerobic, anoxic, and aerobic fermentation processes described above, microorganisms inevitably release gases when decomposing organic matter. For example, methane and alcohols are released during the anaerobic and anoxic stages. Although the aerobic fermentation stage mainly produces carbon dioxide, aeration also carries a small amount of bacterial decomposition products from the wastewater out of the system. These discharged gases are harmful to the environment and therefore need to be treated to remove them. Since the gas pressure generated during the anaerobic and anoxic processes is insufficient, a second blower 40 is needed to extract and discharge the gases. Aerobic fermentation requires aeration, and the system is a positive pressure system. Therefore, there is no need for an extraction device. The gases generated during the above processes can be introduced into the gas boiler 48. This will both supplement the gas boiler 48 with a small amount of gas and allow the gases to be burned for harmless treatment.

[0045] like Figure 4 As shown, optionally, the hydrolysis reactor 2 includes a shell 21, and a reaction tube 22 is disposed inside the shell 21;

[0046] The reaction tube 22 is coiled and folded into multiple layers inside the shell 21;

[0047] The input end of the reaction tube 22 passes through the lower part of the side of the housing 21 and extends out of the housing 21; the input end of the reaction tube 22 passes through the upper part of the side of the housing 21 and extends out of the housing 21.

[0048] The shell 21 is connected to the constant temperature water tank 45 to form a circuit.

[0049] When the alkalized wastewater is hydrolyzed in the hydrolysis reactor 2, the alkalized wastewater enters from the inlet end of the reaction tube 22. At the same time, the constant temperature water tank 45 in the microbial decomposition system 4 introduces hot water (temperature 40±2℃) into the shell 21 to exchange heat with the alkalized wastewater in the reaction tube 22, heating it to about 35℃, so as to accelerate the hydrolysis of formamide in the alkalized wastewater under alkaline conditions.

[0050] like Figure 5 As shown, optionally, a plurality of porous plates 221 are arranged in an array inside the reaction tube 22, and each porous plate 221 is arranged perpendicular to the axis of the reaction tube 22.

[0051] In the application, the alkaline wastewater enters from the input end of the reaction tube 22, and the turbulent degree of the alkaline wastewater is increased when passing through the perforated plate 221 due to the small holes on the perforated plate 221, so that the alkaline wastewater is stirred.

[0052] As shown in Figure 6 Optionally, an electrolytic cell 6 is arranged between the aeration tank 3 and the microbial decomposition system 4.

[0053] In the application, the electrolytic cell 6 can be used to remove a part of the organic matter in the wastewater by electrolytic oxidation in advance, so as to facilitate the subsequent biochemical process. When working, the wastewater enters the electrolytic cell 6 as an electrolyte, and oxidation and reduction reactions occur at the anode and cathode respectively, and harmful substances are removed.

[0054] A formamide wastewater treatment device, and the working process is as follows:

[0055] In use, the formamide-containing wastewater transported by the formamide wastewater pipeline 10 is added to the mixing tank 1, and the alkali metering pump 20 pours the alkali solution into the mixing tank 1 according to the preset proportion, mixes with the formamide wastewater, adjusts the pH value to alkaline (such as 8-10), and obtains alkaline wastewater. The alkaline wastewater is transported to the hydrolysis reactor 2 for reaction, and the formamide in the wastewater is hydrolyzed into formic acid and ammonia gas. When the alkaline wastewater is hydrolyzed in the hydrolysis reactor 2, the alkaline wastewater enters from the input end of the reaction tube 22, and the turbulent degree of the alkaline wastewater is increased when passing through the perforated plate 221 due to the small holes on the perforated plate 221, so that the alkaline wastewater is stirred. At the same time, the constant-temperature water tank 45 in the microbial decomposition system 4 pours hot water (temperature is 40±2℃) into the shell 21, heats the alkaline wastewater in the reaction tube 22 to about 35℃, so as to accelerate the hydrolysis of the formamide in the alkaline wastewater under alkaline conditions. After the hydrolysis reaction in the hydrolysis reactor 2, the wastewater (at this time, the formamide in the wastewater is hydrolyzed into formate and ammonia gas) is poured into the aeration tank 3, the first fan 30 is used to pour compressed air into the aeration tank 3, the ammonia gas in the wastewater is discharged by blowing and aeration of the air (and the water temperature is relatively high, about 35℃, which is also beneficial to the escape of ammonia gas), and the discharged ammonia gas and compressed air are collected (the collection cover can be arranged above the aeration tank 3 to collect the gas discharged from the aeration tank 3), and then enter the absorption tower 5 (such as a spray tower) to absorb the ammonia gas in the wastewater by using clean water, and then discharge. The ammonia water obtained after absorption can also be used in other ammoniation sections of the factory.

[0056] After aeration and stripping, the wastewater is transferred to electrolysis cell 6, where electrolytic oxidation further oxidizes the organic matter in the wastewater into smaller molecular fragments (the pH of the wastewater can also be adjusted to acidity before electrolysis to improve efficiency), facilitating subsequent microbial decomposition. The wastewater, after pretreatment in electrolysis cell 6, is then transported to microbial decomposition system 4 for further biochemical treatment, achieving deep purification of the organic matter.

[0057] During biochemical treatment in the microbial decomposition system 4, the wastewater is first transported to the anaerobic tank 41 where activated sludge containing anaerobic bacteria is used for anaerobic fermentation. After a period of anaerobic fermentation, the wastewater is transferred to the anoxic tank 42 for anoxic fermentation. After the anoxic fermentation is completed, the wastewater is transported to the aerobic tank 43 for aerobic fermentation (air needs to be continuously blown into the aerobic tank 43 through a ventilation system during aerobic fermentation) to ensure the smooth progress of the aerobic fermentation process. After aerobic fermentation, the treated wastewater is transferred to a secondary sedimentation tank 44 for settling, where the activated sludge is separated from the water. The separated activated sludge can be transferred back to the aerobic tank 43 for recycling, and the separated water, i.e., the supernatant, is transferred to an oxidation tank 441 for oxidation with an oxidant (ozone is used in this application). The supernatant is then collected in a reuse water tank 442, which can be used in sections where water quality requirements are not high. Alternatively, the water in the reuse water tank can be transported to a deep purification section, such as ultrafiltration or reverse osmosis, for further treatment to meet water requirements.

[0058] In the anaerobic, anoxic, and aerobic fermentation processes described above, microorganisms are sensitive to temperature, so the fermentation temperature needs to be maintained within a relatively stable range. To avoid the fermentation temperature being too low in some cold seasons and affecting the fermentation process of microorganisms, heat exchange pipes 411 are laid in the anaerobic tank 41, anoxic tank 42, and aerobic tank 43. Hot water at a suitable temperature (40℃±2℃) is supplied to each fermentation tank through a constant temperature water tank 45 to exchange heat and maintain a constant fermentation temperature. The constant temperature of the water in the constant temperature water tank 45 is achieved through heat exchange with the hot water exchange tank 46. The heat source of the hot water exchange tank 46 comes from the gas boiler 48 and the solar collector 47. On sunny days or when there is sufficient sunlight, the solar collector 47 can mainly provide the heat exchange medium for the hot water exchange tank 46, while the gas boiler 48 is on standby to reduce the fuel consumption of the gas boiler 48 and reduce the processing cost. In cold seasons or when there is insufficient sunlight, the gas boiler 48 can mainly provide the heat exchange medium for the hot water exchange tank 46 to maintain stable heat exchange to each fermentation tank and ensure the smooth progress of the biochemical treatment process.

[0059] At the same time, due to the above anaerobic, anoxic and aerobic fermentation process, microorganisms in the decomposition of organic matter will inevitably release gas, such as methane, alcohol and other gases will be released in the anaerobic and anoxic stage; and although the aerobic fermentation stage mainly produces carbon dioxide gas, but due to aeration, a small amount of bacterial decomposition products in the wastewater will also be brought out of the system, the above-mentioned exhaust gas is harmful to the environment, so it needs to be harmless treatment, because the gas pressure produced in the anaerobic and anoxic process is insufficient, so a second fan 40 is needed to suck and discharge the gas therein; and aerobic fermentation needs aeration, and the system is in a positive pressure system, so it can not need to extract the gas equipment, and the gas produced in the above process is introduced into the gas-fired boiler 48, which can supplement a small amount of gas to the gas-fired boiler 48, and the gas can be burned for harmless treatment.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that; it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A formamide wastewater treatment device, characterized in that, It includes a mixing tank (1), a hydrolysis reactor (2), an aeration tank (3), and a microbial decomposition system (4) connected in series. The mixing tank (1) is also connected to the formamide wastewater pipeline (10) and the alkali metering pump (20), respectively; The aeration tank (3) is also connected to the first blower (30) and the absorption tower (5).

2. The formamide wastewater treatment device according to claim 1, characterized in that, The microbial decomposition system (4) includes an anaerobic tank (41), an anoxic tank (42), an aerobic tank (43), a secondary sedimentation tank (44), an oxidation tank (441), and a recycled water tank (442) connected in series. Each of the anaerobic tank (41), anoxic tank (42) and aerobic tank (43) is equipped with a heat exchange tube (411), and each heat exchange tube (411) is connected to a constant temperature water tank (45) to form a loop. The constant temperature water tank (45) is connected to the hot water exchange tank (46) to form a loop, and the hot water exchange tank (46) is connected to the solar collector (47) to form a loop.

3. The formamide wastewater treatment device according to claim 2, characterized in that, The constant temperature water tank (45) is also connected to the gas boiler (48) to form a loop.

4. The formamide wastewater treatment device according to claim 3, characterized in that, The anaerobic tank (41), the anoxic tank (42), and the aerobic tank (43) are respectively equipped with a first gas collection hood (421), a second gas collection hood (422), and a third gas collection hood (423). The first gas collection hood (421) and the second gas collection hood (422) are connected to the gas boiler (48) via the second fan (40), and the third gas collection hood (423) is connected to the gas boiler (48).

5. The formamide wastewater treatment device according to claim 2, characterized in that, The hydrolysis reactor (2) includes a shell (21) and a reaction tube (22) is provided inside the shell (21). The reaction tube (22) is coiled and folded into multiple layers inside the shell (21); The input end of the reaction tube (22) passes through the lower part of the side of the housing (21) and extends out of the housing (21), and the input end of the reaction tube (22) passes through the upper part of the side of the housing (21) and extends out of the housing (21). The shell (21) is connected to the constant temperature water tank (45) to form a loop.

6. The formamide wastewater treatment device according to claim 5, characterized in that, The reaction tube (22) is provided with an array of multiple porous plates (221), each of which is perpendicular to the axis of the reaction tube (22).

7. The formamide wastewater treatment apparatus according to any one of claims 1 to 6, characterized in that, An electrolytic cell (6) is also provided between the aeration tank (3) and the microbial decomposition system (4).

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