Sewage treatment method

Abstract

The invention discloses a sewage treatment method, and belongs to the field of environmental protection engineering, and the method comprises the following steps: vertically arranging a first electrode and a second electrode in a reaction container, establishing an electric field environment in the reaction container through the first electrode and the second electrode, inputting sewage into the reaction container, and putting a biological filler into the reaction container; sludge is domesticated in an electric field environment to obtain activated sludge, and the domesticated activated sludge is put into a reaction container; sewage is continuously input into the reaction container, anaerobic sewage treatment is carried out in the reaction container, a plurality of micro-cathodes and micro-anodes are formed, and the problems that in the current sewage treatment process, the efficiency is not ideal and the efficiency of anaerobic ammonium oxidation bacteria is not stable are expected to be solved in a sludge culture and alternating current sewage electrolysis mode.

Description

Technical Field

[0001] The present invention relates to environmental protection engineering, and particularly to a sewage treatment method. Background Art

[0002] Nitrogen and phosphorus are important nutrient elements in the ecosystem and participate in the life metabolism process of organisms. With the urbanization process, the sewage discharge increases year by year, resulting in an increase in the nitrogen and phosphorus content in water bodies and water eutrophication; the excessive reproduction of aerobic microorganisms, algae and aquatic plants in water bodies has a great impact on the aquatic environment. Traditional sewage treatment mainly uses physical and chemical methods and biological methods. In the process of removing nitrogen and phosphorus by physical and chemical methods, there is a risk of secondary pollution, and the structure of the treatment system is complex. The biological method utilizes the physiological and biochemical functions of microorganisms and realizes nitrogen and phosphorus removal through the combination of aerobic and anaerobic processes. However, in practical applications of the biological method, limited by the aerobic aeration demand and sludge circulation, the energy consumption required for aeration, nitrification liquid dosing, and sludge reflux in the treatment process is high, and the energy consumption can account for more than 60% of the total energy consumption of sewage treatment. Moreover, the amount of excess sludge after treatment is large, requiring additional treatment costs.

[0003] The current mainstream research direction is to improve the sewage treatment process through anaerobic ammonium oxidation. However, limited by the low efficiency of anaerobic ammonium oxidation technology in aspects such as bacterial enrichment, environmental stability, and reaction efficiency, existing anaerobic ammonium oxidizing bacteria use nitrite as an electron acceptor, and although no organic carbon source is required during the denitrification process. After testing, the nitrification process cannot stably oxidize ammonia nitrogen to nitrite. Analyzing the reason, it is because the film-forming time of anaerobic ammonium oxidizing bacteria is long, and limited by the retention ability of anaerobic ammonium oxidizing bacteria, the microbial mass fluctuates greatly, which makes the sewage treatment capacity of existing reactors have obvious limitations or instability factors. Especially during the inoculation process of storage and new construction projects, the doubling period of anaerobic ammonium oxidizing bacteria is long, and the inhibition by COD is particularly obvious. Therefore, how to carry out sewage treatment in a more economical and environmentally friendly way is worthy of research. Summary of the Invention

[0004] The purpose of the present invention is to provide a sewage treatment method, hoping to improve the problems of unsatisfactory efficiency in the current sewage treatment process and unstable efficiency of anaerobic ammonium oxidizing bacteria by culturing sludge and using the method of alternating electrolysis of sewage.

[0005] To solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A sewage treatment method, the method comprising the following steps: configuring an electric field environment; vertically arranging a first electrode in a reaction vessel, and distributing a plurality of second electrodes around the first electrode, externally connecting the first electrode and the second electrodes to a power supply device, and establishing an electric field environment in the reaction vessel by the power supply device through the first electrode and the second electrodes. Domesticating sludge; inputting sewage into the above reaction vessel and putting in biological fillers; domesticating the sludge through the electric field environment to obtain activated sludge. Conducting anaerobic treatment; putting the domesticated activated sludge into the reaction vessel; continuously inputting sewage into the reaction vessel, and conducting anaerobic sewage treatment in the reaction vessel. During the anaerobic sewage treatment, the reaction vessel is in an electric field environment, and a plurality of micro-cathodes and micro-anodes will be formed on the biofilm on the above biological fillers and the activated sludge; the above micro-cathodes serve as electron donors and provide electrons required for denitrification and phosphorus removal by gasification; the above micro-anodes serve as electron acceptors and accept electrons released by nitrification, nitrosation, and anaerobic ammonium oxidation.

[0007] Its design concept is: by setting an alternating current electric field environment in the reaction vessel, countless micro-cathodes and micro-anodes are generated on the biofilm on the biological fillers and the activated sludge under the electric field environment. Among them, the micro-cathodes can serve as electron donors to provide electrons for denitrifying bacteria groups and phosphorus-removing-by-gasification bacteria groups to complete denitrification and phosphorus removal by gasification. The micro-anodes can serve as electron acceptors to accept electrons released by anaerobic ammonium oxidation bacteria groups, nitrifying bacteria groups, and nitrosating bacteria groups to complete microbial metabolic processes such as nitrification, nitrosation, and anaerobic ammonium oxidation, and the reaction vessel replaces aerobic reactions in a fully anaerobic environment, without aeration, reducing energy consumption and improving the efficiency problem in the current sewage treatment process.

[0008] Preferably, before domesticating the sludge in the above electric field environment, it further includes a step of sludge cultivation: inoculating anaerobic ammonium oxidation granular sludge in the reaction vessel, adding first sewage, and conducting anaerobic cultivation until the activity of the sludge is restored to obtain first sludge. Adding 2 g / L of iron-carbon into the reaction vessel, continuing to add the first sewage, and reaching the determination condition through anaerobic cultivation to obtain second sludge; the above second sludge is used for domestication in the electric field environment. Among them, the determination condition is that the indicators of the current sewage are less than those of the second sewage, and the second sewage is the sewage after cultivating the sludge for two cycles of the first sewage.

[0009] A further technical solution is that during the above sludge cultivation, the parameters of the current sewage are regularly detected, and an activity aid is added to the sewage. The above activity aid includes one or more of anaerobic ammonium oxidation bacteria strains, bacterial chaperones, bacteria promoters, FMBR composite bacteria strains, anaerobic sludge, and SBR sludge, and the determination condition during the sludge cultivation process is maintained by the activity aid.

[0010] A further technical solution is that the first sewage is sewage specially prepared by adjusting the composition of actual domestic sewage. The COD of the first sewage is 90 - 100 mg / L, the TP is 5 - 6 mg / L, the TN is 150 - 160 mg / L, the AN is 135 - 145 mg / L, and the pH is 7.0 - 8. Among them, the Ma of the above-mentioned first sludge reaches more than 40%, the Me reaches more than 60%, and the Mi reaches more than 30%. Among them, the Ma of the above-mentioned second sludge reaches more than 80%, the Me reaches more than 90%, and the Mi reaches more than 70%.

[0011] Preferably, when domesticating activated sludge in an electric field environment, the following steps are included: S100, determining the concentration of the reaction sludge, and selecting iron-carbon with a metallic iron content reaching 60% as the microbial electro-domestication medium; when introducing sewage into the reaction vessel, sequentially setting the influent time, aeration time, sedimentation time, and drainage time to form a reaction cycle.

[0012] Preferably, when domesticating activated sludge in an electric field environment, the following steps are further included: S200, presetting a domestication cycle, and the above-mentioned domestication cycle includes several reaction cycles. S300, sampling and counting data during the domestication cycle, and the time interval between two adjacent data samplings is greater than 12 hours; measuring the activity of the current sludge through sampling. After any data sampling, if it is determined that the sludge lacks activity, the composition of the sewage is readjusted, and the count is reset to zero; if after sampling N times, where N is a positive integer and N ≥ 7, it is considered that the sludge maintains activity.

[0013] Preferably, when domesticating activated sludge in an electric field environment, the following steps are further included: S400, the above-mentioned power supply device gradually adjusts the electric field environment in the reaction vessel during the domestication cycle; before each adjustment of the electric field environment, determining whether the current sludge maintains activity through sampling; if it lacks activity, maintaining the current electric field environment and adding an activity aid to restore the sludge activity; if it maintains activity, the aeration volume of the aeration pipeline is gradually reduced according to the index data of the sewage during the domestication cycle.

[0014] Preferably, when domesticating activated sludge in an electric field environment, the following steps are further included: S500, when the aeration volume tends to zero, verifying the activity degree of the activated sludge. If the activity degree is normal, the electro-biological domestication is completed to obtain the activated sludge.

[0015] A further technical solution is that when the electrical device gradually adjusts the electric field environment in the reaction vessel during the domestication period, direct current is output to the sewage in the reaction vessel through the second electrode and the first electrode, and the output voltage is set to 0.5V for continuous sludge cultivation. Subsequently, sewage parameters are obtained, and the voltage is gradually increased according to the sewage parameters until the activity in the sludge is stable. Then, the direct current is converted into alternating current for output, and the voltage of the alternating current is configured to be 1.2V and the frequency is 0.4Hz. The sewage parameters are continuously collected. After ensuring that the sludge maintains its activity, the aeration volume is gradually reduced.

[0016] Compared with the prior art, the beneficial effects of the present invention are at least one of the following:

[0017] In the sewage treatment method of the present invention, under an alternating current electric field environment, countless micro-cathodes and micro-anodes are respectively generated by using the biofilm and activated sludge on the biological filler. The micro-cathode can be used as an electron donor to provide electrons for the denitrifying bacteria group and the phosphorus gasification bacteria group to complete denitrification and phosphorus gasification. The micro-anode can be used as an electron acceptor to accept the electrons released by the anaerobic ammonium oxidation bacteria group, nitrifying bacteria group, and nitrite bacteria group to complete microbial metabolic processes such as nitrification, nitrite nitrification, and anaerobic ammonium oxidation. Thus, a full anaerobic reaction is carried out without using an aeration condition, replacing the aerobic tank, and no aeration is required during the anaerobic reaction.

[0018] The present invention uses an electric field environment for sludge domestication. By means of anaerobic treatment, while avoiding the energy consumption of aeration, it improves the current situation that the sludge only reacts slowly in the anaerobic environment, hoping to provide new ideas for cultivating sludge in sewage treatment, and hoping to reduce or replace the use of aerobic / anaerobic alternation in sewage treatment to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic flow chart of the present invention;

[0020] Figure 2 It is a schematic structural diagram of an embodiment of the present invention;

[0021] Figure 3 It is a schematic diagram of the electrode distribution of the present invention;

[0022] Description of the reference numerals:

[0023] 1 - reaction vessel, 2 - water distribution assembly, 3 - biological filler assembly, 4 - aeration pipeline, 5 - water inlet tank, 6 - reflux pipeline, 7 - peristaltic pump, 8 - water distribution pipe, 9 - reflux valve, 10 - drain pipe, 11 - first electrode, 12 - second electrode, 13 - power supply device. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0025] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative positional relationship, movement conditions, etc. under a certain specific working state. If the specific posture changes, the directional indication will also change accordingly. In the present invention, unless otherwise clearly specified and limited, terms such as "connection" should be understood in a broad sense. For example, "connection" can be an electrical signal connection or a signal connection; it can also be the internal connection of two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] If there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and / or" appearing throughout the text includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or the solution where A and B are satisfied simultaneously. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0027] Currently, SBR (Sequencing Batch Reactor) is a highly efficient and flexible sewage treatment process, which belongs to an improved type of activated sludge process. Its core feature is to adopt an intermittent operation mode, and complete processes such as influent, reaction, sedimentation, drainage, and idling in a single reactor in stages, achieving efficient removal of organic pollutants, nitrogen, and phosphorus. In this article, the relevant definitions of sludge are explained as follows:

[0028] SBR sludge: The main type of sludge currently used in sewage treatment, mainly through intermittent aerobic and anoxic cycles to achieve the oxidation of organic matter and nitrification / denitrification for nitrogen removal. Therefore, when using SBR sludge in the sewage treatment process, it is necessary to rely on aeration to provide oxygen. The microbial colonies of SBR sludge have a relatively fast growth rate during the sewage treatment process.

[0029] Anaerobic sludge: Sludge used for sewage treatment under anaerobic conditions. Mainly through anaerobic bacterial communities dominated by acid-producing bacteria and methanogens, organic matter is decomposed into methane and carbon dioxide. The growth of the microbial community in anaerobic sludge is slow, and usually the doubling time of methanogens takes several days.

[0030] Reference Figure 1 As shown, this embodiment provides a sewage treatment method. The method includes vertically arranging a first electrode in a reaction vessel and distributing a number of second electrodes around the first electrode. The first electrode and the second electrode are externally connected to a power supply device, where the second electrode is connected to the positive pole and the first electrode is connected to the negative pole. An electric field environment is established in the reaction vessel by the power supply device through the first electrode and the second electrode. Input sewage into the above reaction vessel and add biological fillers; domesticate the sludge through the electric field environment to obtain activated sludge; put the domesticated activated sludge into the reaction vessel; continuously input sewage into the reaction vessel, and anaerobic sewage treatment is carried out in the reaction vessel.

[0031] Among them, during anaerobic sewage treatment, the reaction vessel is in an electric field environment. Biofilms on the above biological fillers and activated sludge will form a number of micro-cathodes and micro-anodes; the above micro-cathodes serve as electron donors and provide electrons required for denitrification and phosphorus removal by gasification; the above micro-anodes serve as electron acceptors and accept electrons released by nitrification, nitrosation, and anaerobic ammonium oxidation.

[0032] The method mainly involves putting the domesticated sludge into the reaction vessel to participate in the reaction of activated sludge, and by setting the gradient change of the electric field environment, through the change of the electric field environment, countless micro-cathodes and micro-anodes are generated in the biofilms on the biological fillers and the activated sludge. Among them, the micro-cathodes can serve as electron donors to provide electrons for denitrifying bacteria and phosphorus-removing-by-gasification bacteria to complete denitrification and phosphorus removal by gasification. The micro-anodes can serve as electron acceptors to accept electrons released by anaerobic ammonium oxidation bacteria, nitrifying bacteria, and nitrosating bacteria to complete microbial metabolic processes such as nitrification, nitrosation, and anaerobic ammonium oxidation.

[0033] The applicant believes through experiments that this method domesticates the sludge, causing certain changes in the sludge properties. Thus, in the later stage of sewage treatment, as long as the stability of the sludge activity is ensured, through the change of the electric field environment, the sewage treatment requirements under fully anaerobic conditions can be met. It not only improves the unstable risk caused by existing anaerobic ammonium oxidation sewage, but also does not require aeration equipment to directly participate in anaerobic sewage treatment, greatly optimizing the energy consumption in the sewage treatment process.

[0034] Based on the above embodiments, another embodiment of the present invention is that, in order to avoid the impact risk brought by the mutant environment experienced by the microbial community, before the above-mentioned acclimated sludge, sludge cultivation is further included, and the above-mentioned sludge cultivation is used to adjust the sludge performance; specifically, the following steps are included: inoculating anaerobic ammonium-oxidizing granular sludge into a reaction vessel and adding first sewage, and anaerobically culturing the sewage to reach the determination condition to restore the activity of the sludge and obtain first sludge; adding 2 g / L of iron-carbon into the reaction vessel, continuing to add the first sewage, and reaching the determination condition by anaerobic cultivation to obtain second sludge; the above-mentioned second sludge is used for acclimation in an electric field environment.

[0035] Wherein, the determination condition is that each index of the current sewage is less than each index of the second sewage, and the second sewage is the sewage after the sludge of the first sewage is cultured for two cycles.

[0036] Furthermore, during the above-mentioned sludge cultivation, the parameters of the current sewage are regularly detected, and an activity aid is added to the sewage. The above-mentioned activity aid includes one or more of anaerobic ammonium-oxidizing bacteria strains, bacterial chaperones, bacterium promoters, FMBR composite strains, anaerobic sludge, and SBR sludge, and the determination condition during the sludge cultivation process is maintained by the activity aid.

[0037] For reference, the activity aid provides an abundant biological population, trace elements and structural support for the sludge cultivation process, so as to directly enhance the activity and stability of the key bacterial groups in the sludge and ensure the effectiveness of the biofilm structure. Specifically, the mechanism of action of the activity aid in maintaining the sludge cultivation conditions is as follows: the activity aid is used as a supplementary source of trace elements required for microbial growth, and the metal elements such as Fe, Mn, and Zn contained in it have a significant promoting effect on the activities of key enzymes such as dehydrogenase and catalase; secondly, the porous structure on the surface of the activity aid provides an excellent carrier for the attachment and growth of microorganisms, which is conducive to the formation and stability of the biofilm; finally, the slow-release components in the aid can continuously adjust the system pH value and maintain the redox potential in the ideal range of -150 mV to 50 mV.

[0038] Wherein, the first sewage is sewage specially made by adjusting the components of actual domestic sewage. The COD of the first sewage is 90-100 mg / L, the TP is 5-6 mg / L, the TN is 150-160 mg / L, the AN is 135-145 mg / L, and the pH is 7.0-8. Among them, the Ma of the above-mentioned first sludge reaches more than 40%, the Me reaches more than 60%, and the Mi reaches more than 30%. Among them, the Ma of the above-mentioned second sludge reaches more than 80%, the Me reaches more than 90%, and the Mi reaches more than 70%. Wherein, Ma is the activity of anaerobic ammonium-oxidizing bacteria, Me is the activity of denitrifying bacteria, and Mi is the activity of nitrifying bacteria.

[0039] Referentially, the conditions of the first sewage can ensure that the ratio between COD and TN is close to 0.6:1. Under this ratio, the basic energy demand is met, while a relatively low but sufficient carbon source is provided for anaerobic ammonium-oxidizing bacteria, avoiding excessive competition from heterotrophic bacteria. The high concentrations of TN and AN create conditions favorable for the growth of anaerobic ammonium-oxidizing bacteria, promoting their enrichment in the microbial community. When the TP content is 5 - 6 mg / L, it can meet the nutrient element requirements for microbial growth and will not cause excessive phosphorus release. This enables the conditions of the first sewage to conduct relatively mild domestication of anaerobic ammonium-oxidizing bacteria. The active conditions of the first sludge can satisfy a microbial community structure dominated by denitrifying bacteria, followed by anaerobic ammonium-oxidizing bacteria, and assisted by nitrifying bacteria.

[0040] Referentially, the determination condition is that the indicators of the current sewage are less than those of the second sewage. Mainly by reducing COD, the growth of heterotrophic bacteria is further restricted, and the resource allocation is tilted towards autotrophic anaerobic ammonium-oxidizing bacteria. At the same time, the first sewage is continuously added, and the determination condition is achieved through anaerobic cultivation. When mainly adaptively reducing the concentration range of TN and AN, the conditions need to maintain a sufficient concentration gradient to drive the nitrogen conversion process.

[0041] Meanwhile, considering the added iron-carbon filler, in order to exert the catalytic and electron mediation effects of iron-carbon, TP needs to be reduced to 1 - 2 mg / L, reducing the risk of phosphorus release. Thus, in cooperation with the addition of iron-carbon, better phosphorus control can be achieved. By cultivating the second sludge in this way, compared with the first sludge, the activities of various functional bacterial groups of the second sludge are significantly improved, especially the activity of anaerobic ammonium-oxidizing bacteria doubles, providing guarantee for efficient nitrogen removal in the subsequent electric field environment. Specifically, the highly active microbial community is more sensitive to electron transfer, facilitating the better formation of microelectrode effects after the addition of iron-carbon. In particular, the activity of Mi needs to ensure that the nitrification / denitrification process can continue under low-oxygen or anoxic conditions with the assistance of an electric field. Therefore, in its technical concept, pre-cultivation is mainly carried out through stepwise adjustment of parameters before domesticating the sludge in the electric field environment, reducing the impact risk brought by the mutant environment to the microbial community, and improving the domestication success rate.

[0042] It is worth emphasizing that limited by the relatively large differences in the activities of some sludges themselves, the applicant believes that for the properties of some sludges themselves, especially when the activity of some sludges after electro-domestication cannot reach that of the second sludge and higher-activity sludge cannot be replaced, a reference value can be set based on the activity parameters of the second sludge, and then a certain relative deviation can be set for the detected parameters. That is, when Ma reaches more than 80% of the reference value, Me reaches more than 90% of the reference value, and Mi reaches more than 70% of the reference value, it is considered to meet the determination condition.

[0043] Based on the above embodiments, an embodiment of the present invention is that, preferably, when using activated sludge domesticated in an electric field environment, the following steps are included: S100, determining the concentration of the reaction sludge, and selecting iron-carbon with a single-element iron content reaching 60% as the microbial electro-domestication medium; when introducing sewage into the reaction vessel, sequentially setting the influent time, aeration time, sedimentation time, and drainage time to form a reaction cycle.

[0044] Exemplarily, an iron-carbon composite filler with a single-element iron content of 60% is selected as the electrolysis medium to establish a sludge cultivation system. The following timing control is completed in the reaction vessel: the first influent stage is 0.5 h, the second aeration stage is 6 h, the third sedimentation stage is 1 h, and the last drainage stage is 0.5 h, and then a complete 8-h reaction cycle is formed.

[0045] Based on the above embodiments, an embodiment of the present invention is that when using activated sludge domesticated in an electric field environment, the following steps are further included: S200, presetting a domestication cycle, and the above domestication cycle includes several reaction cycles. S300, performing data sampling and counting within the domestication cycle, and the time interval between two adjacent data samplings is greater than 12 hours; the activity of the current sludge is measured through sampling. Among them, after any data sampling, if it is determined that the sludge lacks activity, the composition of the sewage is readjusted and the count is reset to zero; if sampling is performed N times, where N is a positive integer and N≥7; then it is considered that the sludge maintains activity.

[0046] Exemplarily, continuous operation of 3 reaction cycles for about 24 h is defined as a monitoring cycle. A domestication cycle is composed of multiple monitoring cycles. Periodic sampling analysis is performed in each detection cycle, and the sampling interval is strictly controlled between 12 and 24 hours. Activity indicators such as the specific oxygen uptake rate SOUR of the sludge need to be measured in each monitoring cycle.

[0047] When the SOUR value of the sludge is detected to be lower than 0.15 mgO2 / (gMLSS·h) at any sampling point, it is determined that the sludge is inactivated, and the influent organic matter load needs to be readjusted and the cultivation cycle count is reset. If the sludge activity indicators remain stable within 7 consecutive monitoring cycles, and the sampled SOUR≥0.25 mgO2 / (gMLSS·h), then it is determined that the sludge is activated, and the obtained second sludge is suitable for entering the electrochemistry domestication stage.

[0048] It should be noted that an appropriate amount of active additives also need to be added during the sludge cultivation process. During the sludge cultivation process, the purpose of adding active additives is to directly supplement, activate and stabilize the microbial community from a biological perspective. By directly supplementing, activating and stabilizing the functional microbial community and its attachment structure in the sludge, the purpose of internal microecological regulation can be achieved. When adding active additives during sludge acclimation, it mainly provides sufficient biological populations, trace elements and structural support for the acclimation process, mainly by adjusting the influent water quality to induce the system to move towards an ideal nutrient substrate ratio state to meet the external supply conditions.

[0049] Furthermore, when acclimating activated sludge through an electric field environment, the following steps are also included: S400, the above-mentioned power supply device gradually adjusts the electric field environment in the reaction vessel during the acclimation cycle; before each adjustment of the electric field environment, it is determined whether the current sludge maintains its activity through sampling; if the activity is lacking, the current electric field environment is maintained, and active additives are added to restore the sludge activity; if the activity is maintained, the aeration pipeline gradually reduces the aeration volume according to the index data of the sewage during the acclimation cycle.

[0050] On the one hand, by determining whether the current sludge maintains its activity through sampling and making adjustments after determining the activity, it can be ensured that before the sludge is adjusted, the activity is detected before each stage of adjustment to ensure that the bacterial community has fully adapted to the previous electric field change. Only by ensuring that the physiological state of the microbial colony is relatively stable can the risk of stress response of key functional bacteria caused by increasing the electric field parameters be avoided as much as possible. The risk of inhibited microbial metabolism or large-scale inactivation is avoided. Objectively, this method can better ensure that the performance of the current sludge will not significantly decline in terms of nitrogen and phosphorus removal and stability due to operational errors, and sampling and detecting the activity before each adjustment of the electric field parameters can play the role of a protective threshold. On the other hand, gradually reducing the aeration volume is to simulate a low-oxygen / anaerobic environment assisted by the electric field, so as to strengthen and determine whether the sludge has the ability to metabolize relying on the electric field under anoxic conditions. To ensure that the acclimated sludge can still maintain efficient nitrogen and phosphorus removal under zero-aeration conditions during the actual engineering operation, so as to achieve significant energy savings and the feasibility of the electro-biological synergistic nitrogen removal system.

[0051] For reference, if it is found through sampling that the activity has decreased or tends to be inactivated, such as the SOUR value is too low, it indicates that the current electric field has reached or is close to the tolerance limit of the bacterial community, and it is necessary to stop the adjustment in time, maintain the status quo and add active additives for repair to prevent the collapse of the overall system. On the contrary, if the sludge activity is good, it can be determined that the existing community structure and metabolic pathway have successfully adapted to the current electric field and can safely enter the next adjustment.

[0052] It should be noted that if the activity is missing, the current electric field environment should be maintained and an activity promoter should be added. Feedback also needs to be obtained through sampling so as to give an early warning when the sludge activity drops. At the same time, the addition of the activity promoter can be adjusted in a timely manner to achieve the controllability of supplementing nutrients and restoring the conditions of the previous step, ensuring that irreversible inactivation will not occur when the subsequent electric field gradually increases.

[0053] Further, when domesticating activated sludge through the electric field environment, the following steps are also included: S500, when the aeration volume tends to zero, verify the activity degree of the activated sludge. If the activity degree is normal, the electro-biological domestication is completed to obtain the activated sludge.

[0054] For reference, considering that the sludge still has activity after the aeration volume tends to zero, but it cannot be ensured whether the domestication of the sludge is sufficient or whether the microbial population is adaptable. Therefore, the sludge domesticated through the electric field and low-oxygen environment needs to be continuously detected for a period of time to ensure that the domesticated sludge has the stability to efficiently complete denitrification relying on the electric field drive under the condition of completely no aeration.

[0055] Further, when the electric equipment gradually adjusts the electric field environment in the reaction vessel during the domestication cycle, direct current is output to the sewage in the reaction vessel through the second electrode and the first electrode, and the output voltage is set to 0.5V for continuous sludge cultivation; then the sewage parameters are obtained, and the voltage is gradually increased according to the sewage parameters until the activity in the sludge is stable, and then the direct current is converted into alternating current for output. The voltage of the alternating current is configured to be 1.2V and the frequency is 0.4Hz. Continuously collect the sewage parameters. After ensuring that the sludge maintains its activity, gradually reduce the aeration volume.

[0056] Among them, the low voltage condition of 0.5V in the initial stage is mainly to protect the safety of microorganisms to adapt. During the process of sludge cultivation, the voltage is gradually increased to assist in activating the electron transfer pathway in the microorganisms, promoting the enhancement of the activity of key bacterial groups and the establishment of metabolic pathways, ensuring that the tolerance of the sludge can meet the subsequent electric field conditions.

[0057] Under the condition of 1.2V, the direct current and alternating current are switched to avoid the polarization effect and enhance the electron mobility, further improving the microbial activity and the electrochemical performance of the system. After determining the stability of the alternating current field and the activity of the sludge, it is considered that the sludge has a certain adaptability, and then the aeration volume is gradually reduced to test the functional performance of the sludge in the system under low / anaerobic conditions until the sludge functional conditions meet the anaerobic environment.

[0058] For reference, set the time period of the electro-domestication stage, and combine with the existing programmable power supply module to regulate the electric field environment of the reaction vessel to meet the gradient electric field requirements. During the domestication period, apply a 0.5V DC voltage, and continuously monitor the sewage water quality parameters such as COD, TN, TP, and AN through the on-line water quality monitoring system. According to the indicators of COD, TP, TN, AN, etc. detected in real time, by dynamically optimizing the applied voltage, stepping 0.1V each time, until the total nitrogen removal efficiency of the system reaches 70% and is in a stable state. Then switch to an AC power supply of 1.2V / 0.4Hz and maintain the system operation for more than 2 complete monitoring cycles. Evaluate the activity degree of the sludge in the electric field environment through the index data, and then adopt a stepped aeration volume control strategy, reducing the aeration intensity by 10% each time, and finally realizing that the sludge still maintains stable nitrogen and phosphorus removal performance under zero aeration conditions, ensuring at least a COD removal rate > 85% and a TP removal rate > 90%, completing the domestication and obtaining activated sludge.

[0059] It should be noted that, if necessary, an evaluation model can also be established through the double-index evaluation system of SOUR and dehydrogenase activity, and the indicators of COD, TN, TP, and AN collected in real time through the on-line water quality monitoring system are input into the evaluation model to directly obtain the evaluation result of the activity degree.

[0060] For reference, see Figure 2 and Figure 3 As shown, the above sewage treatment method can use a sewage treatment domestication system. Refer to Figure 2 As shown, the sewage treatment domestication system includes a reaction vessel 1. The reaction vessel 1 is internally provided with a water distribution component 2 and a biological filler component 3. The biological filler component 3 is placed above the water distribution component 2. A water distribution area is formed between the water distribution component 2 and the bottom of the reaction vessel 1. An aeration pipeline 4 is placed in the water distribution area. One side of the reaction vessel 1 is provided with a water inlet tank 5. A reflux pipeline 6 is provided on the water inlet tank 5. The reflux pipeline 6 is connected to the upper part of the reaction vessel 1. The reaction vessel 1 is used for sewage treatment.

[0061] Furthermore, the water distribution component 2 includes a peristaltic pump 7 and a water distribution pipe 8. The input side and the output side of the peristaltic pump 7 are respectively communicated with the water inlet tank 5 and the water distribution pipe 8. The water distribution pipe 8 extends from the side wall of the reaction vessel 1 into the functional gap. A number of output holes are provided on the water distribution pipe 8. A reflux valve 9 is provided on the reflux pipeline 6, and the reflux valve 9 controls the flow state of the reflux pipeline 6.

[0062] The height-diameter ratio of the reaction zone of the above-mentioned reaction vessel 1 is 8:1; a drain pipe 10 is provided at the upper part of the reaction vessel 1, and the supernatant in the reaction vessel 1 is output through the drain pipe. Among them, the design with a height-diameter ratio of 8:1 is beneficial to the distribution of electrodes and the uniformity of the electric field. By designing a higher reaction zone, it can ensure that the electric field distribution between the electrode wires is relatively uniform, thereby improving the electron transfer efficiency in the sewage. At the same time, the higher reaction zone can reduce the turbulence of the water flow and maintain the water flow stability, thereby ensuring that the residence time of the sewage in the reactor is sufficient, promoting the degradation of organic matter and the removal of nitrogen, and avoiding the occurrence of dead zones or poor flow conditions.

[0063] Among them, a first electrode 11 is vertically arranged in the reaction vessel 1, and a number of second electrodes 12 are distributed around the first electrode. The first electrode 11 and the second electrode 12 are externally connected to a power supply device 13, and the power supply device 13 adjusts the voltage environment in the reaction vessel 1 through the first electrode 11 and the second electrode 12.

[0064] Among them, the power supply device needs to be able to control the output current and set the voltage value required for the experiment. Therefore, existing products can be selected for the power supply device, such as existing devices like the ASR-2000 series programmable AC / DC power supply, Mean Well LRS-150 adjustable power supply module, etc., to meet current control and voltage output.

[0065] Based on the foregoing embodiments, this embodiment is an experimental embodiment. The experiment is used to simulate the system of the above-mentioned embodiments, and the sludge and sewage are both selected from the SBR tank of the sewage treatment plant. The iron-carbon filler is a spherical filler with a particle size of 3-6 mm; the reaction vessel is selected as an organic glass tube, and the effective volume is ensured to be 6000 ml. The reactor is cylindrical, with an inner diameter of 10 cm and a total height of 90 cm. The height-diameter ratio of the reaction zone is 8:1. From bottom to top, there are an aeration pipe, a water distribution area, and a reaction area. Seven stainless steel wire electrodes are vertically arranged around the reaction area, and one stainless steel wire electrode is vertically arranged in the center to simulate the second electrode 12 and the first electrode 11. Its power supply device can be an existing AC / DC energy storage power supply, such as similar products like the HNAT-6000A portable energy storage power supply.

[0066] The purchased anaerobic ammonium oxidation granular sludge is inoculated in a 2500 ml glass bottle. The volume of the anaerobic ammonium oxidation granular sludge is 400 ml, numbered 8252# original sample. Anaerobic culture sampling and analysis are carried out, and the parameters of the 8252# original sample in the following cycle are obtained, and the following data are obtained:

[0067] Sample Number / Analysis Date COD TP TN AN 8252# As-received Sample / 230831 197.64 1.26 95.22 89.26 8252# As-received Sample / 230901 39.53 1.08 80.11 78.11

[0068] Preliminary analysis shows that the total nitrogen removal rate of the sludge is 93.75 gN / M3.d, and the sludge activity of the 8252# original sample is not high. Therefore, the sewage is adjusted to be input into the first sewage for cultivation, and anaerobic culture sampling and analysis are continued, and the following data are obtained:

[0069] Sample Number / Analysis Date COD TP TN AN 8252# Composite Sample Replacement / 240418 185.32 1.15 191.81 130.49 8252# Composite Sample Replacement / 240419 42.67 0.98 108.09 96

[0070] The nitrogen loading rate NRR of the anaerobic ammonium oxidation granular sludge is calculated from the above data: 523.25 gN / M3·d. The first sewage is used for anaerobic cultivation until the activity of the sludge is restored.

[0071] Subsequently, 10 g of iron-carbon is added, and the sewage is adjusted to the second sewage for continued cultivation. The sample number is changed to 8252# and the original sample is replaced. During the cultivation process, the water is changed regularly to prevent the increase in salinity from affecting the domestication of the sludge. During the cultivation and domestication process, anaerobic ammonium oxidation bacteria strains, bacterial companions, bacteria promoters, FMBR composite strains, and anaerobic sludge are added. It is gradually adjusted, monitored, and the sample number is changed to 8252# and the combined sample is replaced. The sampling situation of the 8252# combined sample replacement is as follows:

[0072] Sample Number / Analysis Date COD TP TN AN 8252# Composite Sample Replacement / 240418 892.5 13.35 245.2 152 8252# Composite Sample Replacement / 240419 849 13.08 143 146.9

[0073] The nitrogen loading rate NRR of the anaerobic ammonium oxidation granular (sludge volume 700 ml) system is calculated from the above data: 365.0 gN / M3·d. The sludge nitrogen loading is acceptable, and the tolerance of the sludge to COD is improved. The sludge has completed pre-cultivation, and the 8252# combined sample replacement is used as the second sludge for subsequent sludge domestication.

[0074] On the basis of the foregoing embodiments, in order to confirm the effect of the test treatment method, an embodiment of the present invention is to conduct a sewage treatment test.

[0075] The reaction sludge used in the test comes from the SBR tank of a sewage treatment plant. The sludge has good activity and is in the form of yellow-brown flocs, where SV30 = 31.5%. The MLSS of the inoculated SBR tank sludge is 4000 mg·L-1. Iron-carbon is added under the condition of 10 g / L, and the elemental iron content of the iron-carbon is 60%. Polyurethane foam fillers are added, and the total volume is 2 L. The sample number is 920 Lingang sludge culture, and the pH value is adjusted to 7.2.

[0076] Among them, the sample number 920 Lingang sludge culture is used as the reaction sludge, and its parameters are as follows:

[0077] [[ID=2(]] Sample Number / Analysis Date COD TP TN AN 920 Lingang Sludge Cultivation / 240923 94.87 5.42 155.39 139.39

[0078] The adjusted sewage is pumped to the marked line, with an influent time of 15 min, aeration for 3.0 h, sedimentation for 8.5 h, and drainage for 15 min, totaling 12 h. Two reaction cycles are carried out every day, and sampling and analysis are performed once a day. The following data are obtained:

[0079] Sample Number / Analysis Date COD TP TN AN 920 Lingang Sludge Cultivation / 240930 39.53 2.18 50.61 40.50

[0080] After evaluating the cultivation data, the sludge activity is normal, and the sewage is adjusted to enter the next step. The sludge sample numbered 920 in Lingang is placed in an electric field environment. First, the electric field environment outputs direct current, the voltage is set at 0.5V, 7 surrounding stainless steel wire electrodes are connected to the positive electrode, and one stainless steel wire electrode in the center is connected to the negative electrode. Continue to react for two cycles every day. According to the cultivation data, increase the voltage by 0.1V each time and sample and analyze once a day. During the operation and cultivation process, add 100 ml of the second sludge every day (sample numbered 8252# combined sample replacement). React, and after 12 cycles, complete the pretreatment and obtain the following sludge parameter data:

[0081]

[0082]

[0083] The above sludge parameters are stable on the same day and the activity is normal. Proceed to the next step, output alternating current, the voltage is set at 1.2V, the frequency is 0.4Hz, and 7 surrounding stainless steel wire electrodes and one stainless steel wire electrode in the center form a circuit. React for two cycles every day and sample and analyze once a day to obtain the following data:

[0084] Sample Number / Analysis Date COD TP TN AN 920 Lingang Sludge Cultivation / 241025 158.11 2.016 24.49 26.13

[0085] After evaluating the cultivation data, the sludge activity is normal, and then the sewage is adjusted to enter the next step. Change the direct current to alternating current for output, the voltage is set at 1.2V, the frequency is 0.4Hz, and 7 surrounding stainless steel wire electrodes and one stainless steel wire electrode in the center form a circuit. According to the inflow for 15 minutes, aeration for 3.0 hours, sedimentation for 8.5 hours, and drainage for 15 minutes, a total of 12 hours. React for two cycles every day. According to the cultivation data, reduce the aeration time by 30 minutes each time and increase the sedimentation time by 30 minutes, and sample and analyze once a day until there is no aeration.

[0086] Sample Number / Analysis Date COD TP TN AN 920 Lingang Sludge Cultivation / 241129 223.93 0.692 4.01 3.74

[0087] After evaluating the cultivation data, the sludge activity is normal and the sludge electro-domestication is completed.

[0088] To verify the stability of the alternating current biological sewage treatment technology, a running experiment is carried out. Open the reflux valve of the device, close the outlet valve, turn off the air pump, adjust the water sample, turn on the peristaltic pump, turn on the power supply, set the frequency at 0.4Hz, voltage at 1.2V, and current at 26 mA, and circulate and process the water sample. Arrange sampling tubes of BEW-AN100 ammonia nitrogen water quality automatic online monitor and BEW-TN100 total nitrogen water quality automatic online monitor in the inlet water tank, and set to analyze once a day. The following parameters are obtained:

[0089]

[0090]

[0091] Based on the above data, the nitrogen removal rate (NRR) of the anaerobic ammonium oxidation granular sludge (with a sludge volume of 1900 ml and a sewage volume of 25 L) system is about 39.5 gN / m³·d. The nitrogen load of the system is relatively low, and the nitrogen load capacity of the system still needs to be cultivated and improved. For subsequent research on dealing with different sludge concentrations, that is, the MLSS is in the range of 3000 - 8000 mg / L, gradient tests are carried out, which is beneficial to investigating the quantitative relationship between the dosage of the additive of 0.5% - 2.5% and the sludge sedimentation performance SV30 in the later stage. At the same time, the synergistic effects of dissolved oxygen DO > 2 mg / L and temperature 20 - 30°C need to be monitored. The experimental data show that when the dosage of the additive is 1.2%, the specific oxygen uptake rate (SOUR) of the sludge can be increased by 35%, and the denitrification efficiency reaches the optimum.

[0092] It should be noted that the present invention can also be combined with existing upflow anaerobic sludge bed (UASB), activated sludge process, biofilm process, etc. for combined application, which can conveniently upgrade and transform existing sewage treatment plants.

[0093] When referring to "an embodiment", "another embodiment", "the embodiment", etc. in this specification, it means that the specific features, structures or characteristics described in connection with the embodiment are included in at least one embodiment generally described in this application. The same expression appearing in multiple places in the specification does not necessarily refer to the same embodiment. Further, when describing a specific feature, structure or characteristic in connection with any one embodiment, it is intended that the implementation of such feature, structure or characteristic in combination with other embodiments also falls within the scope of the present invention.

[0094] Although the present invention has been described with reference to multiple illustrative embodiments of the present invention, it should be understood that those skilled in the art can design many other modifications and embodiments, which will fall within the scope of the principles and spirit disclosed in this application. More specifically, within the scope of the disclosure, drawings and claims of this application, various variations and improvements can be made to the components and / or layout of the subject combination layout. In addition to the variations and improvements made to the components and / or layout, other uses will also be obvious to those skilled in the art.

Claims

1. A sewage treatment method, characterized in that, The method includes the following steps: Configure the electric field environment; vertically arrange a first electrode in the reaction vessel, and distribute a number of second electrodes around the first electrode. Connect the first electrode and the second electrodes to an external power supply device, and establish an electric field environment in the reaction vessel by the power supply device through the first electrode and the second electrodes. Domesticate the sludge; input sewage into the reaction vessel and put in biological fillers. Domesticate the sludge through the electric field environment to obtain activated sludge. Carry out anaerobic treatment; put the domesticated activated sludge into the reaction vessel; continuously input sewage into the reaction vessel, and carry out anaerobic sewage treatment in the reaction vessel. During anaerobic sewage treatment, the reaction vessel is in an electric field environment. Micro-cathodes and micro-anodes will be formed on the biofilm on the biological fillers and the activated sludge; the micro-cathodes serve as electron donors and provide electrons required for denitrification and phosphorus removal by gasification; the micro-anodes serve as electron acceptors and accept electrons released by nitrification, nitrosation, and anaerobic ammonium oxidation.

2. The sewage treatment method according to claim 1, characterized in that: Before domesticating the sludge, sludge cultivation is also included, and the sludge cultivation is used to adjust the sludge properties; specifically, it includes the following steps: Inoculate anaerobic ammonium oxidation granular sludge in the reaction vessel and add first sewage. Through anaerobic cultivation of the sewage to reach the determination conditions, restore the activity of the sludge to obtain first sludge. Add 2 g / L of iron-carbon into the reaction vessel, continue to add first sewage, and reach the determination conditions through anaerobic cultivation to obtain second sludge; the second sludge is used for domestication in an electric field environment. Among them, the determination conditions are that the indicators of the current sewage are less than those of the second sewage, and the second sewage is the sewage after cultivating the sludge for two cycles of the first sewage.

3. The sewage treatment method according to claim 2, wherein: During the sludge cultivation, regularly detect the parameters of the current sewage, and add an activity aid to the sewage. The activity aid includes one or more of anaerobic ammonium oxidation bacteria strains, bacterial chaperones, bacteria promoters, FMBR composite strains, anaerobic sludge, and SBR sludge. The activity aid maintains the determination conditions during the sludge cultivation process.

4. The sewage treatment method according to claim 2, wherein: During the sludge cultivation, the indicators of the first sewage include COD of 90 - 100 mg / L, TP of 5 - 6 mg / L, TN of 150 - 160 mg / L, AN of 135 - 145 mg / L, and pH of 7.0 - 8. Among them, the Ma of the first sludge reaches more than 40%, the Me reaches more than 60%, and the Mi reaches more than 30%. Among them, the Ma of the second sludge reaches more than 80%, the Me reaches more than 90%, and the Mi reaches more than 70%.

5. The sewage treatment method according to claim 1, characterized in that: When domesticating activated sludge through an electric field environment, it includes the following steps: S100, determine the concentration of the reaction sludge, and select iron-carbon with a single iron content reaching 60% as the microbial electro-domestication medium; when introducing sewage into the reaction vessel, set the influent time, aeration time, sedimentation time, and drainage time in sequence to form a reaction cycle.

6. The sewage treatment method according to claim 5, wherein: When domesticating activated sludge through an electric field environment, it includes the following steps: S200, preset a domestication cycle, and the domestication cycle includes several reaction cycles. S300, carry out data sampling and counting within the domestication cycle, and the time interval between adjacent two data samplings is greater than 12 hours; measure the activity of the current sludge through sampling. Among them, after any data sampling, if it is determined that the sludge lacks activity, the composition of the sewage is readjusted and the count is reset to zero; if after sampling N times, where N is a positive integer and N≥7, it is considered that the sludge maintains activity.

7. The sewage treatment method according to claim 6, characterized in that: When domesticating activated sludge through an electric field environment, the following steps are further included: S400, the power supply device gradually adjusts the electric field environment in the reaction vessel during the domestication cycle; before each adjustment of the electric field environment, it is determined whether the current sludge maintains activity through sampling; If it lacks activity, maintain the current electric field environment and add an activity aid to restore the sludge activity; if it maintains activity, the aeration pipeline gradually reduces the aeration volume according to the index data of the sewage during the domestication cycle.

8. The sewage treatment method according to claim 7, wherein: When domesticating activated sludge through an electric field environment, the following steps are further included: S500, when the aeration volume tends to zero, verify the activity degree of the activated sludge. If the activity degree is normal, the electro-biological domestication is completed to obtain the activated sludge.

9. The sewage treatment method according to claim 7, wherein: When the electric device gradually adjusts the electric field environment in the reaction vessel during the domestication cycle, direct current is output to the sewage in the reaction vessel through the second electrode and the first electrode, and the output voltage is set to 0.5V for continuous sludge cultivation; then the sewage parameters are obtained, and the voltage is gradually increased according to the sewage parameters until the activity in the sludge is stable, and then the direct current is converted into alternating current for output. The voltage of the alternating current is configured to be 1.2V and the frequency is 0.4Hz. The sewage parameters are continuously collected. After ensuring that the sludge maintains activity, the aeration volume is gradually reduced.

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