A sewage treatment process applicable to sewage treatment in alpine regions

Abstract

The present invention relates to a sewage treatment process applicable to sewage treatment in alpine regions, which includes the following steps: Step 2, input the pretreated wastewater into the first container, connect the power supplies of the first cathode and the first anode for electrocatalytic oxidation, and use the first dosing device to add persulfate into the first container. The electrocatalytic oxidation process and the decomposition process of persulfate cooperate with each other to remove at least COD and ammonia nitrogen in the wastewater; Step 3, input the intermediate wastewater into the second container, connect the power supplies of the second cathode and the second anode. The second anode loses electrons and forms metal cations, and the metal cations combine with OH- to generate a flocculation group with adsorption ability, and use the flocculation group to remove suspended solids, total phosphorus and part of COD in the intermediate wastewater. This process has low dependence on temperature, can be normally used in alpine regions, and can be quickly started and meet the standards rapidly, especially suitable for emergency treatment of alpine sewage.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment in alpine regions, and particularly relates to a sewage treatment process suitable for sewage treatment in alpine regions. Background Art

[0002] At present, domestic and foreign research mainly focuses on the treatment of agricultural sewage in alpine environments. The ideas or methods are to make adaptive improvements to existing biochemical processes. For example, screening and culturing low-temperature strains to reduce the dependence on water temperature; adopting measures such as deep well treatment and heat preservation to avoid too low water temperature and ensure the normal metabolism and reproduction of organisms. However, for scenarios with too low water temperature (such as water temperature below 5°C), heating and heat preservation are still required to ensure the life and normal metabolism of microorganisms in the biochemical process. In reality, in the northern regions and western alpine regions of China, as the water temperature decreases, the activity of activated sludge in the biochemical process gradually decreases, the sedimentation performance deteriorates, and the removal of organic matter, nitrification, and denitrification will all be greatly impacted. When the temperature is below 15°C, the activity of normal-temperature microorganisms will drop sharply, and the nitrification effect will be significantly reduced; moreover, research shows that when the temperature steadily drops to about 10°C, some microorganisms will be in a dormant state; when the temperature drops to the range of 4°C, most microorganisms in the biochemical process will enter the dormant period or even die, resulting in almost complete cessation of nitrification in the sewage treatment system; in addition, the low-temperature environment also provides suitable growth conditions for small chest worms and the like in the biochemical process, and their overgrowth will lead to sludge bulking, thereby affecting the effluent quality; that is to say, when the water temperature drops to about 4°C or even lower, the biochemical process can hardly operate normally and cannot achieve the purpose of sewage treatment.

[0003] For emergency disaster relief, a sewage treatment system and process that can be quickly started and is simple and reliable are required. In the emergency rescue in alpine regions, temperature is a factor that must be considered. In most alpine regions, the night temperature in summer is also very low, and the existing biochemical processes are difficult to start and continuously operate, which is quite difficult for emergency disaster relief.

[0004] At present, there are not many technologies for sewage treatment in alpine regions. Basically, they are all extensions and variations of biochemical processes, supplemented by other heating, heat preservation, or low-temperature strain technologies. For example, when searching with "alpine sewage" as the keyword, 41 results can be retrieved. Among them, there are 18 items with the classification number C02Fx / 14, and 23 items in other categories such as / 02 / 10 / 30 (devices), etc. There is only 1 item using chemical treatment in / 04, but its actual content does not involve any chemical treatment and still uses the biochemical process. That is to say, the existing technologies basically use the biochemical process to treat alpine sewage. And from the search results, it can be seen that the sewage treatment in alpine regions still uses the biochemical process technology adopted by traditional sewage treatment plants, and then takes measures such as heat preservation according to the characteristics of low temperature in alpine regions, or uses low-temperature strains to reduce the dependence on temperature. Although it has a certain feasibility for sewage treatment in alpine regions, there are some obvious drawbacks. For example, first, these methods still do not solve the limitation of the low-temperature environment on biological activities in the biochemical process; second, the biochemical system and process itself have a very slow start-up problem, so it cannot meet the scenario where emergency sewage treatment needs to start quickly and reach the standard quickly; third, it is uneconomical and has a higher cost. For example, for the biochemical process using low-temperature strains, the cost of low-temperature strains is high, and for the biochemical process using heating measures (such as solar heating, electric heating, etc.), a large amount of energy is consumed during the heating process.

[0005] Therefore, it is necessary to develop a sewage treatment process that can start quickly, reach the standard quickly, has a low operating cost, and has a low dependence on temperature to meet the needs of emergency treatment of alpine sewage. Summary of the Invention

[0006] The first aspect of the present invention aims to solve the above technical problems and provides a sewage treatment process suitable for sewage treatment in alpine regions. It can not only start quickly, reach the standard quickly, and have a low operating cost, but also has a low dependence on temperature, and is especially suitable for emergency treatment of alpine sewage. The main concept is as follows:

[0007] A sewage treatment process suitable for sewage treatment in alpine regions includes a sewage treatment system. The sewage treatment system includes a pretreatment module, an electrocatalytic oxidation module, and an electrocoagulation module. The electrocatalytic oxidation module is arranged downstream of the pretreatment module, and the electrocoagulation module is arranged downstream of the electrocatalytic oxidation module. The electrocatalytic oxidation module includes a first container for providing a reaction site and a first dosing device. A first cathode and a first anode are arranged in the first container. The first anode uses a noble metal electrode plate. The electrocoagulation module includes a second container for providing a reaction site. A second cathode and a second anode are arranged in the second container. The second anode uses a consumable anode plate. The sewage treatment process includes the following steps:

[0008] Step 1: First, input the wastewater into the pretreatment module for pretreatment;

[0009] Step 2: Input the pretreated wastewater into the first container, connect the power supplies of the first cathode and the first anode for electrocatalytic oxidation, and use the first dosing device to add persulfate into the first container. The persulfate decomposes in the first container, and the electrocatalytic oxidation process and the decomposition process of persulfate cooperate with each other to remove at least COD and ammonia nitrogen in the wastewater, and obtain intermediate wastewater;

[0010] Step 3: Input the intermediate wastewater into the second container, connect the power supplies of the second cathode and the second anode. During the power-on process, the second anode loses electrons and forms metal cations. The metal cations combine with OH - in the intermediate wastewater to generate a flocculation group with adsorption ability, and use the flocculation group to remove suspended solids, total phosphorus and part of COD in the intermediate wastewater;

[0011] Step 4: Drain the supernatant in the second container. In this solution, during the electrocatalytic oxidation process in the first container, persulfate is added into the first container synchronously, so that the electrocatalytic oxidation process and the decomposition process of persulfate can cooperate with each other. Under the action of electricity, a large number of hydroxyl radicals can be generated by electrocatalytic oxidation. Persulfate can increase the conductivity of water, thereby improving the efficiency of electrocatalytic oxidation, and can quickly oxidize organic matter, ammonia nitrogen, etc. in water; and the added persulfate can quickly generate sulfate radicals under the catalysis of transition metals and noble metals, which can not only significantly improve the catalytic efficiency of persulfate, but also the sulfate radicals have strong oxidation effects and can accelerate the degradation and mineralization of organic matter, so as to achieve the purpose of improving efficiency and quickly meeting the standards; by configuring an electroflocculation module downstream of the electrocatalytic oxidation module and configuring a consumable anode plate in the electroflocculation module, the second anode loses electrons and forms metal cations during the power-on process. The metal cations combine with OH - in the intermediate wastewater to generate a flocculation group with adsorption ability, which has a strong flocculation effect, so that the flocculation group can be used to further remove suspended solids, total phosphorus and part of COD in the intermediate wastewater, which is beneficial to further improve the water quality. Compared with the existing sewage treatment process based on biochemical process, this sewage treatment process has a low dependence on temperature and can operate normally in alpine regions; the whole process does not require heating of the wastewater, and the operating cost is low; there is no start-up time, it can be started quickly, and can quickly meet the standards, especially suitable for the emergency treatment of sewage in alpine regions.

[0012] To solve the problem of unified treatment of domestic wastewater in alpine regions, preferably, the pretreatment module includes a temporary storage container, which is connected to a downstream first container, and the temporary storage container is used to collect and temporarily store the upstream wastewater. In this way, the temporarily stored wastewater can be homogenized and equalized, which is more conducive to subsequent more stable and better wastewater treatment.

[0013] To reduce the burden on subsequent processes, in some embodiments, the temporary storage container is also provided with an overflow port, and the wastewater in the temporary storage container overflows into the first container through the overflow port; alternatively, the temporary storage container is also provided with a transfer pump, and the wastewater in the temporary storage container is input into the first container through the transfer pump. At this time, the temporary storage container can not only homogenize and equalize the collected wastewater, but also settle out most of the solids and settleable substances by gravity sedimentation, and only the supernatant is input into the subsequent first container through the overflow port or the transfer pump for further treatment.

[0014] In other embodiments, the pretreatment module further includes a gravity sedimentation device, the gravity sedimentation device includes a sedimentation container for providing a sedimentation site, the temporary storage container is connected to the sedimentation container, the sedimentation container is connected to the first container, and the sedimentation container is used to sediment the settleable substances in the wastewater, and the supernatant in the sedimentation container is input into the first container. By configuring the gravity sedimentation device, it can be used to sediment the settleable substances in the wastewater to achieve the purpose of preliminary purification of the wastewater.

[0015] Preferably, in step 2, the residence time of the wastewater in the first container is 5 - 60 min.

[0016] To solve the problem of improving the removal rates of COD and ammonia nitrogen at low temperatures, further, the current density of the first cathode and the first anode being energized is 8 A·dm -2 , the duration of electrocatalytic oxidation is 15 min, and the concentration of persulfate is 2 mmol / L.

[0017] To solve the problem of improving the synergistic cooperation between the electrocatalytic oxidation process and the decomposition process of persulfate, preferably, one or more catalytic coatings are further provided on the surface of the first anode and / or the first cathode.

[0018] Preferably, the first anode and / or the first cathode uses titanium material as the substrate, and one or more catalytic coatings are provided on the surface of the substrate. The catalytic coating can be made of materials such as platinum, iridium or rhodium. On the one hand, the catalytic coating can play a role in protecting the substrate, and on the other hand, it can catalyze the electrocatalytic oxidation process to generate more hydroxyl radicals; at the same time, it can catalyze the decomposition process of persulfate, so that a large amount of sulfate radicals are quickly decomposed from the persulfate, so that the electrocatalytic oxidation process and the decomposition process of persulfate can achieve a synergistic enhancement effect.

[0019] To solve the problem of improving the adsorption effect, preferably, the second anode is made of iron or aluminum. The second anode made of iron or aluminum belongs to a consumable anode plate. After being energized, the anode loses electrons to form metal cations Fe 2+ or Al 3 + . The metal cations can combine with OH- in the intermediate wastewater to form highly active flocculation groups, which have extremely strong adsorption ability and better flocculation effect than ordinary flocculants. By using their adsorption bridging and net trapping and sweeping effects, the pollutants in the wastewater (especially suspended solids, total phosphorus, and part of COD) can be adsorbed and co-precipitated to remove them, achieving the purpose of further purifying the wastewater.

[0020] Preferably, the residence time of the intermediate wastewater in the second container is 20 - 30 min.

[0021] Compared with the prior art, using the sewage treatment process provided by the present invention for sewage treatment in alpine regions has a simple process flow and low operating cost. It can not only be quickly started and meet the standards rapidly, thus meeting the needs of emergency relief situations, but also has low dependence on temperature and can be used normally in alpine regions, especially suitable for emergency treatment of alpine sewage. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, so they should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0023] Figure 1 FIG. 1 is a schematic structural diagram of a sewage treatment system provided in Embodiment 1 of the present invention.

[0024] Figure 2 FIG. 2 is a schematic structural diagram of a sewage treatment system provided in Embodiment 2 of the present invention.

[0025] Description of Markings in the Drawings

[0026] Pretreatment module 100, temporary storage container 101, sedimentation container 102

[0027] Electrocatalytic oxidation module 200, first container 201, first cathode 202, first anode 203, first dosing device 204, storage container 205, power unit 206, dosing pipeline 207

[0028] Electroflocculation module 300, second container 301, second cathode 302, second anode 303

[0029] Delivery pump 400. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present invention.

[0031] Example 1

[0032] See also Figure 1 In this embodiment, a sewage treatment process suitable for sewage treatment in high-cold areas is provided, especially a sewage treatment process suitable for emergency domestic sewage treatment in high-cold areas, which specifically includes a sewage treatment system adapted to the process, such as Figure 1 As shown, the sewage treatment system includes a pre-treatment module 100, an electrocatalytic oxidation module 200 and an electro-flocculation module 300, wherein:

[0033] In this embodiment, the electrocatalytic oxidation module 200 is disposed downstream of the pre-treatment module 100 and is connected to the pre-treatment module 100. Figure 1 As shown, the electro-flocculation module 300 is disposed downstream of the electro-catalytic oxidation module 200 and is connected to the electro-catalytic oxidation module 200 . The electro-flocculation module 300 inputs purified wastewater.

[0034] like Figure 1 As shown, in this embodiment, the pre-treatment module 100 is mainly used for uniform pre-treatment of wastewater in high-cold areas, such as domestic wastewater. In a relatively simple implementation, the pre-treatment module 100 includes a temporary storage container 101, and each upstream sewage discharge point can be connected to the temporary storage container 101 respectively. For example, the upstream kitchen sewage outlet can be connected to the temporary storage container 101 through a pipe, the sewage outlet in the upstream bathroom can also be connected to the temporary storage container 101 through a pipe, and the sewage outlet of the upstream wash basin can also be connected to the temporary storage container 101 through a pipe, so that domestic wastewater from various places can be gathered in the temporary storage container 101, so that the temporary storage container 101 can collect and temporarily store upstream wastewater; at the same time, the temporary storage container 101 is connected to the first container 201 downstream, such as Figure 1As shown, a temporary storage container 101 is used to homogenize and equalize the collected wastewater, which is more conducive to subsequent more stable and better wastewater treatment.

[0035] During implementation, an overflow port can be configured in the temporary storage container 101 so that the wastewater in the temporary storage container 101 can overflow into the first container 201 through the overflow port. Since only the supernatant can overflow, in this way, the temporary storage container 101 can not only homogenize and equalize the collected wastewater, but also remove most of the solids and settleable substances through gravity sedimentation. Similarly, a transfer pump 400 can also be configured for the temporary storage container 101 so that the wastewater in the temporary storage container 101 can be input into the first container 201 through the transfer pump 400 via a pipeline, and the same effect can be achieved, which will not be elaborated here.

[0036] As Figure 1 shown, in this embodiment, the electrocatalytic oxidation module 200 includes a first container 201 for providing a reaction site and a first dosing device 204 for dosing persulfate. A first cathode 202 and a first anode 203 are configured in the first container 201. The first cathode 202 and the first anode 203 respectively form a closed loop with a power source. In this embodiment, the first cathode 202 and the first anode 203 can respectively adopt noble metal electrode plates. And in a preferred implementation manner, one or more catalytic coatings are further provided on the surface of the first anode 203 and / or the first cathode 202. The catalytic coatings are used to reduce the activation energy of the organic matter in the wastewater, thereby facilitating the removal of the organic matter in the wastewater. For example, during implementation, the first anode 203 and / or the first cathode 202 can adopt titanium material as the substrate. At the same time, one or more catalytic coatings are provided on the surface of the substrate. The catalytic coatings can be made of materials such as platinum, iridium, and rhodium. On the one hand, the catalytic coatings can play a role in protecting the substrate, and on the other hand, they can catalyze the electrocatalytic oxidation process to generate more hydroxyl radicals; at the same time, they can catalyze the decomposition process of persulfate, so that a large number of sulfate radicals are quickly decomposed from the persulfate, so that the electrocatalytic oxidation process and the decomposition process of persulfate can achieve a synergistic enhancement effect.

[0037] During implementation, the first dosing device 204 includes a power unit 206 for providing dosing power, a storage container 205 for preparing and / or storing persulfate, and a dosing pipeline 207. One end of the dosing pipeline 207 is connected to the storage container 205, and the other end is disposed at a position adapted to the first container 201. The power unit 206 is connected to the dosing pipeline 207. The power unit 206 may preferably be a pump, so as to use the pump to transport the persulfate in the storage container 205 into the first container 201. In order to dose persulfate quantitatively and precisely, in a more perfect solution, the power unit 206 may preferably be a metering pump, so as to accurately calculate the amount of persulfate dosed during transportation. Of course, in a more complete solution, it further includes a controller, and the controller is electrically connected to the power unit 206. When the controller is used to control the power unit 206 to start, and when the amount of persulfate transported reaches the set threshold, the power unit 206 can be automatically shut down to achieve the purpose of automatically stopping the transportation.

[0038] In this embodiment, the electrocatalytic oxidation module 200 is mainly used to rapidly oxidize organic matters, ammonia nitrogen, etc. in the wastewater through the electrocatalytic oxidation process, and utilize the sulfate radicals with strong oxidation generated by persulfate to accelerate the degradation and mineralization of organic matters, so that the electrocatalytic oxidation process and the decomposition process of persulfate can form a synergistic cooperation; the shape of the first container 201 is not limited in this embodiment, as long as it can accommodate the wastewater to be treated; during implementation, the first container 201 may be a structure. For example, the first container 201 may be surrounded by reinforced concrete. For the convenience of emergency, in a preferred implementation manner, the first container 201 may preferably be surrounded by stainless steel plates and only needs to be installed on site; for example, the first container 201 may be a reaction tank, reaction trough or reaction cylinder surrounded by stainless steel plates, etc. Another example is that the first container 201 may also be a reaction tank.

[0039] As Figure 1 shown, in this embodiment, the electrocoagulation module 300 includes a second container 301 for providing a reaction site. A second cathode 302 and a second anode 303 are arranged in the second container 301. The second anode 303 is a consumable anode plate, that is, during use, the second anode 303 itself will be continuously consumed. In this embodiment, the electrocoagulation module 300 is mainly used to remove total phosphorus in the wastewater by electrocoagulation. At the same time, it can also remove suspended solids and part of COD in the wastewater, so as to achieve the purpose of further purifying the wastewater.

[0040] Similarly, the shape of the second container 301 is not limited in this embodiment, as long as it can hold the wastewater to be treated; in implementation, the second container 301 can be a structure. For example, the second container 301 can be surrounded by reinforced concrete. For the convenience of emergency, in a preferred implementation, the second container 301 can preferably be surrounded by stainless steel plates and only needs to be installed on site, which is more convenient and efficient; for example, the second container 301 can be a reaction tank, reaction trough or reaction cylinder surrounded by stainless steel plates, and the second container 301 can also be a reaction tank, etc.

[0041] In implementation, the second anode 303 can preferably be made of iron or aluminum. The second anode 303 made of iron or aluminum belongs to a consumable anode plate. After being energized, the anode loses electrons to form metal cations Fe 2+ or Al 3+ . The metal cations can combine with OH - in the intermediate wastewater to form highly active flocculation groups, which have extremely strong adsorption ability and better flocculation effect than ordinary flocculants. By using its adsorption bridging and net trapping and sweeping effects, the pollutants in the wastewater (especially suspended solids, total phosphorus and part of COD) can be adsorbed and co-precipitated to remove them, achieving the purpose of further purifying the wastewater.

[0042] Based on this sewage treatment system, the sewage treatment process provided in this embodiment includes the following steps:

[0043] Step 1: First, input the wastewater into the pretreatment module 100 for pretreatment. Through pretreatment, on the one hand, the wastewater to be treated can be homogenized and equalized to prevent the fluctuations of factors such as the water volume and water quality of the upstream wastewater from affecting the effect of subsequent wastewater treatment. On the other hand, the impurities, settleable substances, etc. in the wastewater can be removed in advance to complete the preliminary treatment of the wastewater and avoid problems such as blockage in subsequent treatment links.

[0044] Step 2: Input the pretreated wastewater into the first container 201, connect the power supplies of the first cathode 202 and the first anode 203 for electrocatalytic oxidation. Meanwhile, use the first dosing device 204 to add persulfate into the first container 201. The persulfate decomposes in the first container 201, and these two processes are carried out simultaneously, enabling the electrocatalytic oxidation process and the decomposition process of persulfate to cooperate synergistically. Among them, under the action of electricity, a large number of hydroxyl radicals can be generated during the electrocatalytic oxidation process. At the same time, the added persulfate can significantly increase the conductivity of the wastewater (because the salt content in domestic wastewater is usually very low), thereby improving the efficiency of electrocatalytic oxidation, and thus quickly oxidizing organic matter, ammonia nitrogen, etc. in the water. And the added persulfate can rapidly generate sulfate radicals under the catalysis of transition metals and noble metals, which can not only significantly improve the catalytic efficiency of persulfate, but also the sulfate radicals have strong oxidation effects, thereby accelerating the degradation and mineralization of organic matter, effectively removing COD and ammonia nitrogen, etc. in the wastewater, making the synergistic cooperation process can significantly improve the purification efficiency and purification effect of the wastewater.

[0045] During implementation, the persulfate can be potassium persulfate, ammonium persulfate, sodium persulfate, etc.

[0046] In this step, since the first anode 203 uses a noble metal electrode plate, the electrocatalytic oxidation process does not consume the first cathode 202 and the first anode 203. Electrons transfer between the electrode plate and the organic matter (i.e., COD) in the wastewater. The electrons transfer through the electrode plate to the organic matter and are mineralized and adsorbed on the anode surface. Since there is one or more catalytic coatings on the surface of the first anode 203, the catalytic coatings can be used to catalytically reduce the activation energy of the organic matter, which can not only effectively remove most of the COD in the wastewater, but also has the characteristics of high efficiency, low energy consumption, strong mineralization ability, and thorough oxidation.

[0047] During the entire electrocatalytic oxidation process, the oxidation includes direct oxidation and indirect oxidation. Among them, direct oxidation refers to the direct loss of electrons by pollutants at the anode to occur oxidation; indirect oxidation is to use anions with lower electrode potentials in the solution, such as OH - 、Cl - to lose electrons at the anode to generate new stronger oxidizing active substances, such as [O], [OH], Cl 2 etc., so that these active substances can be used to oxidize and decompose BOD5, COD, NH 3-N, etc. Similarly, the reduction in the electrocatalytic oxidation process also includes direct reduction and indirect reduction. Among them, direct reduction refers to the reduction of pollutants by directly obtaining electrons on the cathode; indirect reduction refers to the cations in the pollutants first obtaining electrons on the cathode, enabling the high-valent or low-valent metal cations in the wastewater (electrolyte) to directly obtain electrons on the cathode and be reduced to low-valent cations or metal precipitates.

[0048] During operation, the decomposition of persulfate generates sulfate radicals, which have an oxidation potential similar to that of hydrogen peroxide, and can thus rapidly oxidize organic matter in water. The decomposition process of persulfate can be catalyzed by energy such as photoelectricity and heat. In this embodiment, a heterogeneous metal catalyst (i.e., the catalytic coating is disposed on the substrate, which is a solid coating and does not dissolve in water together with persulfate, thus forming a heterogeneous phase. During actual operation, the catalytic coating will not be fully mixed with sulfate, but only mixed with the sulfate diffused to the catalytic coating) is used to activate persulfate. The catalyst can be reused and will not produce secondary pollution during the reaction process, which is a highly promising activation method.

[0049] During implementation, the residence time of the wastewater in the first container 201 can be preferably controlled to be 5 - 60 min, which is beneficial for improving efficiency and can also ensure the effluent quality.

[0050] Step 3: Take the supernatant in the first container 201 as intermediate wastewater and input it into the second container 301. Connect the power supply of the second cathode 302 and the second anode 303 to start the electrocoagulation process. This process extends the reaction time of the electrocatalytic synergistic persulfate oxidation in step 2, and can make more full use of the reagents and energy. At the same time, since the second anode 303 uses a consumable anode plate, the second anode 303 loses electrons during the energization process and forms metal cations. The metal cations combine with OH - in the intermediate wastewater to form flocculation groups with adsorption ability, so as to remove suspended solids, total phosphorus, and some residual COD in the intermediate wastewater by using the generated flocculation groups. For example, when the second anode 303 is made of Fe, the second anode 303 loses electrons during the energization process and generates Fe 2+ in the wastewater. Fe 2+ can combine with OH - in the intermediate wastewater to form iron hydroxide, etc. Iron hydroxide has a strong flocculation effect and can remove a large amount of suspended solids, total phosphorus, and some COD in the water; another example is when the second anode 303 is made of Al, the second anode 303 loses electrons during the energization process and generates Al 3+ in the wastewater. Al 3+ can combine with OH -Combined to generate aluminum hydroxide, etc. Ferric hydroxide has a strong flocculation effect and can also effectively remove a large amount of suspended solids, total phosphorus, and part of COD in water, achieving the purpose of further purifying wastewater.

[0051] During implementation, the residence time of the intermediate wastewater in the second container 301 can be 20 - 30 minutes. This not only helps improve efficiency but also ensures the effluent quality.

[0052] Step 4: Drain the supernatant in the second container 301 to complete the purification treatment of the wastewater. In the entire sewage treatment process, advanced oxidation relies mainly on chemical agents or electric energy, etc., making this sewage treatment process start quickly, less affected by environmental temperature, and can be used under the condition that the water body does not freeze. It is especially suitable for emergency projects of alpine sewage.

[0053] Using this sewage treatment process has at least the following advantages: 1. It can reduce the dependence on temperature, enabling normal use in alpine regions, solving the technical defects usually existing in sewage treatment in alpine regions, such as the poor effect or even inability to work of commonly used biochemical technologies restricted by low temperature.

[0054] 2. Utilize the high efficiency of electro-catalytic coordination, give full play to the advantages of good stability and strong oxidizing property of persulfate, and can quickly remove pollutants such as organic matter, colloids, and microparticles in water.

[0055] 3. It can simultaneously meet the requirements of reducing COD, total phosphorus, ammonia nitrogen, and suspended solids, etc. At the same time, the residual chlorine generated can be used for disinfection.

[0056] 4. It starts quickly and has no start-up time, which can meet the situation of emergency relief;

[0057] 5. This sewage treatment process is easy to be equipped, occupies a small area, involves few chemicals and is easy to store, convenient for transportation and application.

[0058] 6. During the reaction process of this sewage treatment process, no secondary pollution is generated, and there are few side reactions. It is a clean green technology.

[0059] 7. This sewage treatment process has low operation requirements and is simple and reliable in operation.

[0060] 8. In steps 2 and 3 of this sewage treatment process, during the electro-catalytic coordination of persulfate oxidation and electro-flocculation, chloride ions in the wastewater will be oxidized to generate chlorine gas, etc., and then generate oxidizing substances such as sodium hypochlorite, which can effectively kill germs and viruses in the water body. It can not only meet the disinfection effect on the effluent, so that this process does not need to be equipped with disinfection and sterilization links, but also has a certain effect of degrading organic matter, which is beneficial to improving the removal effect of organic matter.

[0061] Example 2

[0062] The main difference between this Embodiment 2 and the above embodiments is that in the sewage treatment process provided in this embodiment, in the sewage treatment system, the pretreatment module 100 further includes a gravity sedimentation device for performing gravity sedimentation treatment on the wastewater. The gravity sedimentation device includes a sedimentation container 102 for providing a sedimentation place, such as Figure 2 shown, the temporary storage container 101 is communicated with the sedimentation container 102. As described in Embodiment 1, the wastewater in the temporary storage container 101 can be input into the downstream sedimentation container 102 by means of overflow, or the wastewater can be input into the downstream sedimentation container 102 by using a transfer pump 400. At the same time, the sedimentation container 102 is communicated with the first container 201. Similarly, the wastewater in the sedimentation container 102 can be input into the downstream first container 201 by means of overflow, or the wastewater can be input into the downstream first container 201 by using a transfer pump 400. In this embodiment, the sedimentation container 102 mainly can adopt the method of static sedimentation to sediment the settleable substances in the wastewater, prevent impurities, solids, etc. mixed in the wastewater from entering the first container 201. During the actual operation process, only the supernatant in the sedimentation container 102 is input into the first container 201 so as to achieve the purpose of preliminarily purifying the wastewater.

[0063] Embodiment 3

[0064] To solve the problem of improving the efficiency and effect in the emergency treatment of sewage in alpine regions in the above sewage treatment process, in this embodiment, the current density when the first cathode 202 and the first anode 203 are electrified in the sewage treatment process is controlled to be 8 A·dm -2 , the concentration of persulfate is controlled to be 2 mmol / L, which can achieve a relatively higher removal rate of COD and ammonia nitrogen. If the duration of electrocatalytic oxidation is too long, the efficiency is low; if the duration is too short, the removal rates of COD and ammonia nitrogen are relatively low. Therefore, during implementation, in order to balance efficiency and removal rate, the duration of electrocatalytic oxidation is preferably controlled to be 12 min - 20 min. When the duration of electrocatalytic oxidation is preferably controlled to be about 15 min, that is, the residence time of the wastewater in the first container 201 is controlled to be about 15 min, it not only has a high treatment efficiency but also can ensure relatively high removal rates of COD and ammonia nitrogen.

[0065] Based on this, in this embodiment, in a certain alpine region, the influence of water temperature and other process parameters on the treatment efficiency and effect of the above sewage treatment process is further explored. Among them, the water quality of the domestic wastewater treated in each group of experiments is basically the same, and the COD content, ammonia nitrogen content, total phosphorus content, and suspended solids in the wastewater are measured in advance.

[0066] Comparative Experiment 1: The water temperature of the wastewater to be treated is about 3.0 °C. The wastewater to be treated is input into the first container 201 for electrocatalytic oxidation. The current density during the electrocatalytic oxidation process is 8 A·dm-2 The concentration of the added persulfate is 2 mmol / L, electrocatalytic oxidation is carried out for 15 min, and then the COD content and ammonia nitrogen content in the supernatant of the first container 201 are measured, and the COD removal rate and ammonia nitrogen removal rate are calculated. The results are shown in Table 1.

[0067] Comparative experiment 2: The temperature of the wastewater to be treated is about 5.0 °C. The wastewater to be treated is input into the first container 201 for electrocatalytic oxidation. The current density during the electrocatalytic oxidation process is 8 A·dm -2 The concentration of the added persulfate is 2 mmol / L, electrocatalytic oxidation is carried out for 15 min, and then the COD content and ammonia nitrogen content in the supernatant of the first container 201 are measured, and the COD removal rate and ammonia nitrogen removal rate are calculated. The results are shown in Table 1.

[0068] Comparative experiment 3: The temperature of the wastewater to be treated is about 8.0 °C. The wastewater to be treated is input into the first container 201 for electrocatalytic oxidation. The current density during the electrocatalytic oxidation process is 8 A·dm -2 The concentration of the added persulfate is 2 mmol / L, electrocatalytic oxidation is carried out for 15 min, and then the COD content and ammonia nitrogen content in the supernatant of the first container 201 are measured, and the COD removal rate and ammonia nitrogen removal rate are calculated. The results are shown in Table 1.

[0069] Comparative experiment 4: The temperature of the wastewater to be treated is about 8.0 °C. The wastewater to be treated is input into the first container 201 for electrocatalytic oxidation. The current density during the electrocatalytic oxidation process is 8 A·dm -2 No persulfate is added, electrocatalytic oxidation is carried out for 15 min, and then the COD content and ammonia nitrogen content in the supernatant of the first container 201 are measured, and the COD removal rate and ammonia nitrogen removal rate are calculated. The results are shown in Table 1.

[0070] Comparative experiment 5: The temperature of the wastewater to be treated is about 8.0 °C. The wastewater to be treated is input into the first container 201, and persulfate with a concentration of 2 mmol / L is added, and it is left standing for 15 min. Then the COD content and ammonia nitrogen content in the supernatant of the first container 201 are measured, and the COD removal rate and ammonia nitrogen removal rate are calculated. The results are shown in Table 1.

[0071] Table 1 Comparison of Comparative Experiments 1 - 5

[0072]

[0073] Combined with the above Table 1, it can be known from the comparison of Comparative Experiment 1, Comparative Experiment 2 and Comparative Experiment 3 that the COD removal rate and ammonia nitrogen removal rate of the wastewater in the electrocatalytic oxidation module 200 hardly change, indicating that the wastewater temperature in alpine regions has little effect on the COD removal rate and ammonia nitrogen removal rate. It can be known from the comparison of Comparative Experiment 3, Comparative Experiment 4 and Comparative Experiment 5 that when electrocatalytic oxidation is carried out alone in the electrocatalytic oxidation module 200 without adding persulfate, or only persulfate is added without electrocatalytic oxidation, the COD removal rate and ammonia nitrogen removal rate will both decrease significantly. Moreover, through comparison, it can be seen that when electrocatalytic oxidation and synchronous addition of persulfate are carried out simultaneously, the COD removal rate and ammonia nitrogen removal rate are significantly increased, indicating that the electrocatalytic oxidation process and the decomposition process of persulfate can produce a synergistic enhancement effect, which can not only effectively remove COD and ammonia nitrogen in the wastewater, but also effectively improve the removal efficiency, enabling the wastewater to meet the standards quickly to meet the requirements of emergency treatment of alpine sewage.

[0074] Comparative Experiment 6: The water temperature of the wastewater to be treated is about 3.0 °C. The wastewater to be treated is input into the second container 301 for electrocoagulation precipitation. The duration of electrocoagulation precipitation is 25 min. Then, the total phosphorus content, COD content and suspended solid content in the supernatant of the second container 301 are measured, and the removal rates of total phosphorus, COD and suspended solids are calculated. The results are shown in Table 2.

[0075] Comparative Experiment 7: The water temperature of the wastewater to be treated is about 5.0 °C. The wastewater to be treated is input into the second container 301 for electrocoagulation precipitation. The duration of electrocoagulation precipitation is 25 min. Then, the total phosphorus content, COD content and suspended solid content in the supernatant of the second container 301 are measured, and the removal rates of total phosphorus, COD and suspended solids are calculated. The results are shown in Table 2.

[0076] Comparative Experiment 8: The water temperature of the wastewater to be treated is about 8.0 °C. The wastewater to be treated is input into the second container 301 for electrocoagulation precipitation. The duration of electrocoagulation precipitation is 25 min. Then, the total phosphorus content, COD content and suspended solid content in the supernatant of the second container 301 are measured, and the removal rates of total phosphorus, COD and suspended solids are calculated. The results are shown in Table 2.

[0077] Comparative Experiment 9: The water temperature of the wastewater to be treated is about 85.0 °C. The wastewater to be treated is input into the second container 301 for electrocoagulation precipitation. The duration of electrocoagulation precipitation is 15 min. Then, the total phosphorus content, COD content and suspended solid content in the supernatant of the second container 301 are measured, and the removal rates of total phosphorus, COD and suspended solids are calculated. The results are shown in Table 2.

[0078] Comparative Experiment 10: The water temperature of the wastewater to be treated is about 85.0 °C. The wastewater to be treated is input into the second container 301 for electrocoagulation precipitation. The duration of electrocoagulation precipitation is 20 min. Then, the total phosphorus content, COD content, and suspended solid content in the supernatant of the second container 301 are measured, and the removal rates of total phosphorus, COD, and suspended solids are calculated. The results are shown in Table 2.

[0079] Comparative Experiment 11: The water temperature of the wastewater to be treated is about 8.0 °C. The wastewater to be treated is input into the second container 301 for electrocoagulation precipitation. The duration of electrocoagulation precipitation is 30 min. Then, the total phosphorus content, COD content, and suspended solid content in the supernatant of the second container 301 are measured, and the removal rates of total phosphorus, COD, and suspended solids are calculated. The results are shown in Table 2.

[0080] Comparative Experiment 12: The water temperature of the wastewater to be treated is about 8.0 °C. The wastewater to be treated is input into the second container 301 for electrocoagulation precipitation. The duration of electrocoagulation precipitation is 35 min. Then, the total phosphorus content, COD content, and suspended solid content in the supernatant of the second container 301 are measured, and the removal rates of total phosphorus, COD, and suspended solids are calculated. The results are shown in Table 2.

[0081] Table 2 Comparison of Comparative Experiments 6 - 12

[0082]

[0083] Combined with Table 2 above, from the comparison of Comparative Experiments 6, 7, and 8, it can be known that the removal rates of total phosphorus, COD, and suspended solids of the wastewater in the electrocoagulation module 300 hardly change, indicating that the wastewater temperature in alpine regions has little effect on the removal rates of total phosphorus, COD, and suspended solids. From the comparison of Comparative Experiments 8 - 12, it can be known that as the duration of electrocoagulation precipitation increases, the removal rates of total phosphorus, COD, and suspended solids in the wastewater increase, indicating that the longer the duration of electrocoagulation precipitation, the better the treatment effect. However, through comparison, it can be seen that as the duration of electrocoagulation precipitation increases, the increase amounts of the removal rates of total phosphorus, COD, and suspended solids per unit interval time all decrease. Therefore, in actual use, considering the sewage treatment efficiency, the residence time of the wastewater in the second container 301 can be preferably controlled within 20 - 30 min, which can not only ensure the removal rates of total phosphorus, COD, and suspended solids, but also take a short time and have relatively high efficiency.

[0084] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention.

Claims

1. A sewage treatment process applicable to sewage treatment in alpine regions, characterized in that, it includes a sewage treatment system, the sewage treatment system includes a pretreatment module, an electrocatalytic oxidation module and an electrocoagulation module. The electrocatalytic oxidation module is arranged downstream of the pretreatment module, and the electrocoagulation module is arranged downstream of the electrocatalytic oxidation module. The electrocatalytic oxidation module includes a first container for providing a reaction site and a first dosing device. A first cathode and a first anode are arranged in the first container. The first anode is a noble metal electrode plate, and one or more catalytic coatings are further arranged on the surface of the first anode and / or the first cathode. The catalytic coating is made of platinum or iridium or rhodium materials; The electrocoagulation module includes a second container for providing a reaction site. A second cathode and a second anode are arranged in the second container. The second anode is a consumable anode plate; the sewage treatment process includes the following steps: Step 1: First input the wastewater into the pretreatment module for pretreatment; Step 2: Input the pretreated wastewater into the first container, connect the power supply of the first cathode and the first anode for electrocatalytic oxidation, and use the first dosing device to add persulfate into the first container. The persulfate decomposes in the first container. The electrocatalytic oxidation process and the decomposition process of the persulfate cooperate with each other to remove at least COD and ammonia nitrogen in the wastewater and obtain intermediate wastewater; wherein, the duration of electrocatalytic oxidation is controlled to be 12 min - 20 min; Step 3: Input the intermediate wastewater into the second container, connect the power supply of the second cathode and the second anode. During the power-on process, the second anode loses electrons and forms metal cations. The metal cations combine with OH in the intermediate wastewater to generate flocculation groups with adsorption ability, and use the flocculation groups to remove suspended solids, total phosphorus and part of COD in the intermediate wastewater. Among them, the residence time of the intermediate wastewater in the second container is 20 - 30 min; - Combined to generate flocculation groups with adsorption ability, and use the flocculation groups to remove suspended solids, total phosphorus and part of COD in the intermediate wastewater. Among them, the residence time of the intermediate wastewater in the second container is 20 - 30 min; Step 4: Drain the supernatant in the second container.

2. The sewage treatment process applicable to sewage treatment in alpine regions according to claim 1, characterized in that, the pretreatment module includes a storage container, the storage container is connected to the first container downstream, and the storage container is used to collect and store the upstream wastewater.

3. The sewage treatment process applicable to sewage treatment in alpine regions according to claim 2, characterized in that, the storage container is further provided with an overflow port, and the wastewater in the storage container overflows into the first container through the overflow port; or, the storage container is further provided with a delivery pump, and the wastewater in the storage container is input into the first container through the delivery pump.

4. The sewage treatment process applicable to sewage treatment in alpine regions according to claim 2, characterized in that, the pretreatment module further includes a gravity sedimentation device, the gravity sedimentation device includes a sedimentation container for providing a sedimentation site, the storage container is connected to the sedimentation container, the sedimentation container is connected to the first container, the sedimentation container is used to sediment the settleable substances in the wastewater, and the supernatant in the sedimentation container is input into the first container.

5. The sewage treatment process applicable to sewage treatment in alpine regions according to claim 1, characterized in that, The current density of the first cathode and the first anode when powered on is 8 A·dm -2 , the duration of electrocatalytic oxidation is 15 min, and the concentration of persulfate is 2 mmol / L.

6. The sewage treatment process applicable to sewage treatment in alpine regions according to any one of claims 1 - 5, characterized in that, the second anode is made of iron or aluminum.

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