A method of sewage treatment

Abstract

The application discloses a sewage treatment method, and belongs to the field of environmental protection engineering, which 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 adding biological filler; domesticating sludge through the electric field environment to obtain activated sludge, and adding the domesticated activated sludge into the reaction container; continuously inputting sewage into the reaction container, and performing anaerobic sewage treatment in the reaction container to form a plurality of micro-cathodes and micro-anodes, so as to improve the problems of unsatisfactory efficiency and unstable efficiency of anaerobic ammonia oxidation bacteria in the current sewage treatment process by culturing sludge and using alternating current to electrolyze sewage.

Description

Technical Field

[0001] This invention relates to environmental engineering, specifically to a wastewater treatment method. Background Technology

[0002] Nitrogen and phosphorus are essential nutrients in ecosystems, participating in the metabolic processes of organisms. With urbanization, wastewater discharge increases annually, leading to elevated nitrogen and phosphorus levels in water bodies and eutrophication. The excessive proliferation of aerobic microorganisms, algae, and aquatic plants in water bodies also significantly impacts aquatic environments. Traditional wastewater treatment primarily employs physicochemical and biological methods. Physicochemical methods pose a risk of secondary pollution during nitrogen and phosphorus removal and have complex systems. Biological methods utilize the physiological and biochemical processes of microorganisms, combining aerobic and anaerobic processes to remove nitrogen and phosphorus. However, in practical applications, biological methods are limited by aerobic aeration requirements and sludge recycling. The energy consumption for aeration, nitrification liquor addition, and sludge return during the treatment process is high, accounting for over 60% of the total energy consumption for wastewater treatment. Furthermore, the large amount of residual sludge after treatment necessitates additional treatment costs.

[0003] Current research focuses on improving wastewater treatment processes through anaerobic ammonia oxidation (ANAO). However, ANAO technology suffers from low efficiency in areas such as microbial enrichment, environmental stability, and reaction efficiency. Existing ANAO bacteria use nitrite as an electron acceptor, and while the denitrification process does not require an organic carbon source, testing has shown that nitrification cannot stably oxidize ammonia nitrogen to nitrite. This is attributed to the long biofilm formation time of ANAO bacteria, limiting their retention capacity and causing significant fluctuations in microbial biomass. This results in significant limitations and instability in the wastewater treatment capacity of existing reactors. The long doubling period of ANAO bacteria and their inhibition by COD are particularly evident during storage and inoculation of new projects. Therefore, research into more economical and environmentally friendly wastewater treatment methods is warranted. Summary of the Invention

[0004] The purpose of this invention is to provide a wastewater treatment method that aims to improve the current wastewater treatment process by cultivating sludge and using alternating current electrolysis of wastewater, thereby addressing the problems of unsatisfactory efficiency and unstable performance of anaerobic ammonia oxidizing bacteria.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A wastewater treatment method includes the following steps: configuring an electric field environment; vertically arranging a first electrode inside a reaction vessel and distributing several second electrodes around it; connecting the first and second electrodes to an external power supply device, which establishes an electric field environment in the reaction vessel through the first and second electrodes; acclimating sludge; inputting wastewater and adding biological packing material into the reaction vessel; acclimating the sludge through the electric field environment to obtain activated sludge; performing anaerobic treatment; adding the acclimated activated sludge into the reaction vessel; continuously inputting wastewater into the reaction vessel for anaerobic wastewater treatment. During anaerobic wastewater treatment, the reaction vessel is under an electric field environment, and the biofilm on the biological packing material and the activated sludge form several microcathodes and microanodes; the microcathodes act as electron donors, providing electrons required for denitrification and gasification phosphorus removal; the microanodes act as electron acceptors, accepting electrons released from nitrification, nitrosation, and anaerobic ammonia oxidation.

[0007] The design concept is as follows: An alternating current electric field is created within the reaction vessel, causing the biofilm and activated sludge on the biological packing material to generate numerous microcathodes and microanodes under this electric field. The microcathodes act as electron donors, providing electrons to denitrifying and phosphorus-removing bacteria to complete denitrification and phosphorus removal. The microanodes act as electron acceptors, receiving electrons released by anaerobic ammonia-oxidizing, nitrifying, and nitrite-oxidizing bacteria to complete microbial metabolic processes such as nitrification, nitrite oxidation, and anaerobic ammonia oxidation. This fully anaerobic environment replaces aerobic reactions, eliminating the need for aeration, reducing energy consumption, and improving the efficiency of current wastewater treatment processes.

[0008] Preferably, before acclimating the sludge in the aforementioned electric field environment, a sludge cultivation step is included: anaerobic ammonia-oxidizing bacteria granular sludge is inoculated into a reaction vessel, first wastewater is added, and anaerobic cultivation is carried out until the sludge activity is restored, obtaining the first sludge. 2 g / L of iron and carbon is added to the reaction vessel, and the first wastewater is continued to be added. The anaerobic cultivation is then carried out until the determination criteria are met, obtaining the second sludge. This second sludge is used for acclimation in an electric field environment. The determination criteria are that all indicators of the current wastewater are lower than all indicators of the second wastewater, and the second wastewater is the wastewater after two cycles of sludge cultivation using the first wastewater.

[0009] A further technical solution is that, during the sludge cultivation process, the current wastewater parameters are periodically monitored, and active additives are added to the wastewater. These active additives include one or more of the following: anaerobic ammonia-oxidizing bacteria, bacterial companions, bacterial growth promoters, FMBR composite bacteria, anaerobic sludge, and SBR sludge. The active additives maintain the judgment conditions during the sludge cultivation process.

[0010] A further technical solution is that the first wastewater is specially formulated wastewater made from actual domestic sewage with adjusted components. The first wastewater has a 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. Specifically, the first sludge has a Ma content of over 40%, a Me content of over 60%, and a Mi content of over 30%. The second sludge has a Ma content of over 80%, a Me content of over 90%, and a Mi content of over 70%.

[0011] As a preferred method, when acclimating activated sludge through an electric field environment, the following steps are included: S100, determining the concentration of the reacting sludge, selecting iron-carbon with an elemental iron content of 60% as the microbial electro-acclimation medium; introducing wastewater into the reaction vessel; and sequentially setting the influent time, aeration time, sedimentation time, and drainage time to form a reaction cycle.

[0012] Preferably, the activated sludge acclimated by an electric field environment further includes the following steps: S200, a preset acclimation period is defined, which includes several reaction cycles. S300, data sampling and counting are performed within the acclimation period, with the time interval between two adjacent data samplings being greater than 12 hours; the activity of the sludge is measured through each sampling. Wherein, after any data sampling, if the sludge is determined to lack activity, the composition of the wastewater is readjusted, and the count is reset to zero; if after N samplings, where N is a positive integer and N≥7, the sludge is considered to have maintained activity.

[0013] As a preferred embodiment, the activated sludge acclimated by the electric field environment also includes the following steps: S400, the power supply equipment gradually adjusts the electric field environment in the reaction vessel during the acclimation period; before each adjustment of the electric field environment, sampling is used to determine whether the current sludge maintains its activity; if activity is lost, the current electric field environment is maintained and an activation agent is added to restore the sludge activity; if activity is maintained, the aeration pipe gradually reduces the aeration rate according to the wastewater index data during the acclimation period.

[0014] As a preferred option, when acclimating activated sludge through an electric field environment, the following steps are also included: S500, when the aeration rate approaches zero, the activity level of the activated sludge is checked. If the activity level is normal, the electrobiological acclimation is completed and activated sludge is obtained.

[0015] A further technical solution is that, during the acclimatization period, as the electrical equipment gradually adjusts the electric field environment in the reaction vessel, it outputs direct current to the wastewater in the reaction vessel through the second and first electrodes, with the output voltage set to 0.5V, and continuously cultivates the sludge. Subsequently, wastewater parameters are acquired, and the voltage is gradually increased based on the wastewater parameters until the activity in the sludge stabilizes. Then, the direct current is converted to alternating current for output, with the alternating current voltage configured to be 1.2V and the frequency 0.4Hz. Wastewater parameters are continuously collected, and after ensuring that the sludge maintains its activity, the aeration rate is gradually reduced.

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

[0017] The wastewater treatment method of this invention generates numerous microcathodes and microanodes under an alternating current electric field environment, utilizing the biofilm and activated sludge on the biological packing material. The microcathodes act as electron donors, providing electrons to denitrifying and phosphorus-removing bacteria to complete denitrification and phosphorus removal. The microanodes act as electron acceptors, receiving electrons released by anaerobic ammonia-oxidizing, nitrifying, and nitrite-oxidizing bacteria to complete microbial metabolic processes such as nitrification, nitrite oxidation, and anaerobic ammonia oxidation. Thus, a fully anaerobic reaction can be carried out without aeration, replacing the aerobic tank, and no aeration is required during the anaerobic reaction.

[0018] This invention employs an electric field environment for sludge acclimation. By using anaerobic treatment, it avoids the energy consumption of aeration while improving the current situation where sludge reacts slowly only in anaerobic environments. It aims to provide a new approach to sludge cultivation in wastewater treatment and to reduce or replace the use of alternating aerobic / anaerobic treatment to some extent. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the process of the present invention;

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

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

[0022] Explanation of reference numerals in the attached figures:

[0023] 1-Reaction vessel, 2-Water distribution assembly, 3-Biological packing assembly, 4-Aeration pipe, 5-Inlet tank, 6-Return pipe, 7-Peristaltic pump, 8-Water distribution pipe, 9-Return valve, 10-Drain pipe, 11-First electrode, 12-Second electrode, 13-Power supply equipment. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the 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 merely illustrative and not intended to limit the invention.

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

[0026] If the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Furthermore, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0027] Currently, the Sequencing Batch Reactor (SBR) is a highly efficient and flexible wastewater treatment process, representing an improvement upon the activated sludge process. Its core characteristic is its intermittent operation, completing the processes of influent, reaction, sedimentation, effluent discharge, and idle time in stages within a single reactor, achieving highly efficient removal of organic pollutants, nitrogen, and phosphorus. The relevant definitions of sludge in this article are explained below:

[0028] SBR sludge: Currently, the main type of sludge used in wastewater treatment primarily achieves organic matter oxidation, nitrification / denitrification denitrification through intermittent aerobic and anoxic cycles. Therefore, the use of SBR sludge in wastewater treatment requires aeration to provide oxygen. The microbial colonies in SBR sludge exhibit a relatively fast growth rate during wastewater treatment.

[0029] Anaerobic sludge: Sludge produced under anaerobic conditions for wastewater treatment. It mainly decomposes organic matter into methane and carbon dioxide through anaerobic bacteria, primarily acid-producing and methanogenic bacteria. The microbial community of anaerobic sludge grows slowly, and methanogenic bacteria typically take several days to multiply.

[0030] refer to Figure 1 As shown, this embodiment provides a wastewater treatment method. The method includes vertically arranging a first electrode inside a reaction vessel and distributing several second electrodes around the first electrode. The first and second electrodes are connected to an external power supply device, wherein the second electrodes are connected to the positive terminal and the first electrode to the negative terminal. The power supply device establishes an electric field environment in the reaction vessel through the first and second electrodes. Wastewater is introduced into the reaction vessel along with biological packing material; sludge is acclimated using the electric field environment to obtain activated sludge; the acclimated activated sludge is added back into the reaction vessel; wastewater is continuously introduced into the reaction vessel for anaerobic wastewater treatment.

[0031] In the anaerobic wastewater treatment process, the reaction vessel is in an electric field environment, and the biofilm and activated sludge on the above-mentioned biological packing material will form several microcathodes and microanodes. The microcathodes act as electron donors and provide electrons required for denitrification and gasification phosphorus removal. The microanodes act as electron acceptors and accept electrons released by nitrification, nitrosation and anaerobic ammonia oxidation.

[0032] The method primarily involves feeding acclimatized sludge into a reaction vessel to participate in the activated sludge reaction. By setting a gradient change in the electric field environment, numerous microcathodes and microanodes are generated in the biofilm on the biological packing material and in the activated sludge. The microcathodes act as electron donors, providing electrons to denitrifying and phosphorus-removing bacteria to complete denitrification and phosphorus removal. The microanodes act as electron acceptors, receiving electrons released by anaerobic ammonia-oxidizing, nitrifying, and nitrite-oxidizing bacteria to complete microbial metabolic processes such as nitrification, nitrite oxidation, and anaerobic ammonia oxidation.

[0033] The applicant, through experimentation, concluded that this method, by acclimating the sludge, alters its properties. Therefore, in subsequent wastewater treatment, as long as the sludge activity remains stable, changes in the electric field environment can achieve the wastewater treatment requirements under fully anaerobic conditions. This not only mitigates the instability risks associated with existing anaerobic ammonia oxidation wastewater treatment but also eliminates the need for direct aeration equipment, significantly optimizing energy consumption in the wastewater treatment process.

[0034] Based on the above embodiments, another embodiment of the present invention, in order to avoid the risk of the microbial community being subjected to the shock of a sudden change in environment, includes sludge cultivation before the above-mentioned sludge acclimation. The above-mentioned sludge cultivation is used to adjust the sludge performance; specifically, it includes the following steps: inoculating anaerobic ammonia oxidizing bacteria granular sludge into a reaction vessel and adding first wastewater, and reaching the determination condition through anaerobic culture of wastewater to restore the activity of the sludge and obtain the first sludge; adding 2 g / L of iron and carbon into the reaction vessel, continuing to add the first wastewater, and reaching the determination condition through anaerobic culture to obtain the second sludge; the above-mentioned second sludge is used for acclimation in an electric field environment.

[0035] The criteria for judgment are that the current wastewater indicators are less than the second wastewater indicators, and the second wastewater is the wastewater after two cycles of sludge cultivation of the first wastewater.

[0036] Furthermore, during the sludge cultivation process, the current wastewater parameters are periodically monitored, and active additives are added to the wastewater. These active additives include one or more of the following: anaerobic ammonia-oxidizing bacteria, bacterial companions, bacterial growth promoters, FMBR composite bacteria, anaerobic sludge, and SBR sludge. The active additives maintain the judgment conditions during the sludge cultivation process.

[0037] For reference, active additives provide sufficient biological populations, trace elements, and structural support for the sludge cultivation process, thereby directly enhancing the activity and stability of key microbial communities in the sludge and ensuring the effectiveness of the biofilm structure. Specifically, the mechanism by which active additives maintain sludge cultivation conditions is as follows: Firstly, as a source of trace elements required for microbial growth, the active additives contain metals such as Fe, Mn, and Zn, which significantly enhance the activity of key enzymes such as dehydrogenases and catalases. Secondly, the porous structure on the surface of the active additives provides an excellent carrier for microbial attachment and growth, which is conducive to the formation and stability of the biofilm. Finally, the slow-release components in the additives can continuously regulate the system pH, maintaining the redox potential within the ideal range of -150mV to 50mV.

[0038] The first type of wastewater is specially formulated from actual domestic sewage with adjusted composition. Its COD is 90-100 mg / L, TP is 5-6 mg / L, TN is 150-160 mg / L, AN is 135-145 mg / L, and pH is 7.0-8. The first type of sludge exhibits a Ma content of over 40%, a Me content of over 60%, and an Mi content of over 30%. The second type of sludge exhibits a Ma content of over 80%, a Me content of over 90%, and an Mi content of over 70%. Ma represents the activity of anaerobic ammonia oxidizing bacteria, Me represents the activity of denitrifying bacteria, and Mi represents the activity of nitrifying bacteria.

[0039] For reference, the conditions of the first wastewater treatment can ensure that the COD to TN ratio is close to 0.6:1. At this ratio, basic energy requirements are met, while providing a low but sufficient carbon source for anaerobic ammonia oxidizing bacteria and avoiding excessive competition from heterotrophic bacteria. High concentrations of TN and AN create conditions favorable for the growth of anaerobic ammonia oxidizing bacteria, promoting their accumulation in the microbial community. A TP content of 5-6 mg / L can meet the nutrient requirements for microbial growth without causing excessive phosphorus release. This allows the first wastewater treatment conditions to allow for a relatively gentle acclimation of anaerobic ammonia oxidizing bacteria. The activity conditions of the first sludge can support a microbial community structure dominated by denitrifying bacteria, followed by anaerobic ammonia oxidizing bacteria, and supplemented by nitrifying bacteria.

[0040] For reference, the criteria for judgment are that all indicators of the current wastewater are lower than those of the second wastewater. This is mainly achieved by reducing COD, further limiting the growth of heterotrophic bacteria, and allocating resources more towards autotrophic anaerobic ammonia-oxidizing bacteria. Simultaneously, the first wastewater is added again, and the judgment criteria are met through anaerobic cultivation. When adaptively reducing the concentrations of TN and AN, sufficient concentration gradients must be maintained to drive the nitrogen conversion process.

[0041] Simultaneously considering the added iron-carbon filler, to maximize its catalytic and electron-mediating effects, TP needs to be reduced to 1-2 mg / L, minimizing the risk of phosphorus release. This, combined with the addition of iron-carbon, allows for better phosphorus control. Cultivating the second sludge using this method significantly enhances the activity of various functional microbial communities compared to the first sludge, particularly doubling the activity of anaerobic ammonia-oxidizing bacteria, ensuring efficient nitrogen removal under the subsequent electric field environment. Specifically, the highly active microbial community is more sensitive to electron transfer, facilitating better microelectrode formation after the addition of iron-carbon. In particular, Mi activity needs to ensure that the nitrification / nitrification process can continue under low-oxygen or anaerobic conditions with the assistance of an electric field. Therefore, the technical concept primarily involves pre-cultivating the sludge in an electric field environment by adjusting parameters in a stepwise manner before acclimatization, reducing the risk of the microbial community being impacted by sudden environmental changes, thereby improving the acclimatization success rate.

[0042] It is worth emphasizing that, due to the potentially large differences in the activity of some sludge, the applicant believes that, given the nature of some sludge, especially when the activity of some sludge after electro-acclimation does not reach that of the second sludge, and it is not possible to replace it with sludge of higher activity, a benchmark value can be set based on the activity parameters of the second sludge, and then a certain relative deviation setting can be assigned to the detected parameters. That is, Ma reaching more than 80% of the benchmark value, Me reaching more than 90% of the benchmark value, and Mi reaching more than 70% of the benchmark value are considered to meet the judgment conditions.

[0043] Based on the above embodiments, one embodiment of the present invention is, preferably, when acclimating activated sludge through an electric field environment, the following steps are included: S100, determining the concentration of the reacting sludge, selecting iron-carbon with an elemental iron content of 60% as the microbial electro-acclimation medium; introducing wastewater into the reaction vessel; and sequentially setting the influent time, aeration time, sedimentation time, and drainage time to form a reaction cycle.

[0044] For example, an iron-carbon composite packing material with 60% elemental iron content was selected as the electrolysis medium to establish a sludge cultivation system. The following time sequence was controlled in the reaction vessel: the first step was the influent stage for 0.5 hours, the second step was the aeration stage for 6 hours, the third step was the sedimentation stage for 1 hour, and the final step was the drainage stage for 0.5 hours, which constituted a complete 8-hour reaction cycle.

[0045] Based on the above embodiments, one embodiment of the present invention further includes the following steps when acclimating activated sludge through an electric field environment: S200, a preset acclimation period is defined, which includes several reaction cycles. S300, data sampling and counting are performed within the acclimation period, and the time interval between two adjacent data samplings is greater than 12 hours; the activity of the current sludge is determined through each sampling. Wherein, after any data sampling, if it is determined that the sludge lacks activity, the composition of the wastewater is readjusted, and the count is reset to zero; if after N samplings, where N is a positive integer and N≥7, the sludge is considered to have maintained activity.

[0046] As an example, a monitoring cycle is defined as three consecutive reaction cycles, approximately 24 hours each. Multiple monitoring cycles constitute an acclimatization cycle. Periodic sampling and analysis are performed in each monitoring cycle, with sampling intervals strictly controlled between 12 and 24 hours. Activity indicators such as the sludge specific oxygen consumption rate (SOUR) must be measured in each monitoring cycle.

[0047] When the SOUR value of the sludge detected at any sampling point is lower than 0.15 mg O2 / (g MLSS·h), the sludge is considered inactive, and the influent organic load needs to be readjusted and the culture cycle count reset. If the sludge activity index remains stable for 7 consecutive monitoring cycles, and the sampled SOUR is ≥ 0.25 mg O2 / (g MLSS·h), the sludge is considered to have completed activation, and the resulting second sludge is suitable for entering the electrochemical acclimatization stage.

[0048] It is important to note that appropriate amounts of active additives need to be added during sludge cultivation. The purpose of adding these additives during sludge cultivation 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 attached structures in the sludge, the goal of internal microecological regulation is achieved. During sludge acclimation, the addition of active additives primarily provides sufficient biological populations, trace elements, and structural support to adjust the influent water quality induction system towards an ideal nutrient substrate ratio, thus meeting external supply conditions.

[0049] Furthermore, the activated sludge acclimation process via an electric field environment also includes the following steps: S400, the aforementioned power supply equipment gradually adjusts the electric field environment in the reaction vessel during the acclimation period; before each adjustment of the electric field environment, sampling is used to determine whether the current sludge maintains its activity; if activity is lacking, the current electric field environment is maintained, and an activation aid is added to restore the sludge activity; if activity is maintained, the aeration pipeline gradually reduces the aeration rate based on the wastewater index data during the acclimation period.

[0050] On the one hand, sampling determines whether the sludge maintains its activity. Adjustments are made based on this activity level, ensuring that the microbial community has fully adapted to the previous electric field changes before each adjustment stage. Only by ensuring the relative stability of the microbial colony's physiological state can we minimize the risk of stress responses in key functional bacteria caused by increasing the electric field parameters. This avoids the risk of metabolic suppression or significant inactivation of the microbial community. Objectively, this method better ensures that the current sludge performance will not significantly decline in denitrification, phosphorus removal, and stability due to operational errors. Furthermore, sampling and activity testing before each electric field parameter adjustment acts as a protective threshold. On the other hand, gradually reducing the aeration rate simulates a low-oxygen / anaerobic environment assisted by an electric field, thereby strengthening and confirming the sludge's ability to metabolize under anoxic conditions using an electric field. This ensures that the acclimated sludge can maintain efficient denitrification and phosphorus removal even under zero aeration conditions in actual engineering operations, achieving significant energy savings and demonstrating the feasibility of an electro-biological synergistic denitrification system.

[0051] For reference, if sampling reveals decreased activity or a tendency towards inactivation, such as an excessively low SOUR value, it indicates that the current electric field has reached or is close to the tolerance limit of the microbial community. Adjustments must be stopped immediately, the current state maintained, and activity-enhancing agents added for repair to prevent overall system collapse. Conversely, if sludge activity is good, it confirms that the existing community structure and metabolic pathways have successfully adapted to the current electric field, and the next adjustment step can be safely initiated.

[0052] It should be noted that if activity is lacking, maintaining the current electric field environment and adding activation aids also requires sampling and feedback. This allows for early warning when a decline in sludge activity is detected. Simultaneously, it enables timely addition of activation aids, ensuring the controllability of nutrient replenishment and restoration of previous conditions. This guarantees that the subsequent gradual strengthening of the electric field will not lead to irreversible deactivation.

[0053] Furthermore, the activated sludge acclimation process via an electric field environment also includes the following steps: S500, when the aeration rate approaches zero, the activity level of the activated sludge is checked. If the activity level is normal, the electrobiological acclimation is completed and activated sludge is obtained.

[0054] For reference, considering that the sludge still has activity after the aeration rate approaches zero, but it cannot be guaranteed whether the sludge has been sufficiently acclimatized or whether the microbial population has the adaptability, the sludge after acclimatization in an electric field and low-oxygen environment needs to be continuously monitored for a period of time to ensure that the acclimatized sludge has the stability to efficiently complete denitrification under completely aeration conditions driven by an electric field.

[0055] Furthermore, during the acclimation period, as the electrical equipment gradually adjusts the electric field environment in the reaction vessel, it outputs direct current to the wastewater in the reaction vessel through the second and first electrodes, with the output voltage set at 0.5V, to continuously cultivate the sludge. Subsequently, wastewater parameters are acquired, and the voltage is gradually increased based on the wastewater parameters until the activity in the sludge stabilizes. Then, the direct current is converted to alternating current for output, with the alternating current voltage configured at 1.2V and the frequency at 0.4Hz. Wastewater parameters are continuously collected, and after ensuring that the sludge maintains its activity, the aeration rate is gradually reduced.

[0056] The initial low voltage condition of 0.5V is mainly to protect the microorganisms and ensure their safe adaptation. During the sludge cultivation process, the voltage is gradually increased to help activate the electron transport pathways within the microorganisms, promote the enhancement of the activity of key bacterial groups and the establishment of metabolic pathways, and ensure that the sludge can withstand the electric field conditions in the later stages.

[0057] By switching between DC and AC power at 1.2V, polarization effects are avoided and electron mobility is enhanced, further improving microbial activity and system electrochemical performance. After determining the stability of the AC electric field and the activity of the sludge, it is considered that the sludge has a certain degree of adaptability. Then, the aeration rate is gradually reduced to test the functional performance of the sludge under low / anaerobic conditions until the sludge functional conditions meet the anaerobic environment requirements.

[0058] For reference, a time period for the electro-acclimation phase is set. The electric field environment of the reaction vessel is adjusted using existing programmable power modules to meet the gradient electric field requirements. During the acclimation period, a 0.5V DC voltage is applied, and the wastewater quality parameters, such as COD, TN, TP, and AN, are continuously monitored in real time through an online water quality monitoring system. Based on the real-time detected COD, TP, TN, and AN indicators, the applied voltage is dynamically optimized, increasing by 0.1V each time, until the total nitrogen removal efficiency of the system reaches 70% and stabilizes. Then, the system is switched to a 1.2V / 0.4Hz AC power supply to maintain operation for at least two complete monitoring cycles. The activity level of the sludge under the electric field environment is evaluated using the indicator data. Then, a step-by-step aeration rate control strategy is adopted, reducing the aeration intensity by 10% each time, ultimately achieving stable nitrogen and phosphorus removal performance of the sludge even under zero aeration conditions, ensuring at least a COD removal rate >85% and a TP removal rate >90%, thus completing the acclimation and obtaining activated sludge.

[0059] It is worth noting that, when necessary, an evaluation model can be established using a dual-indicator assessment system of SOUR and dehydrogenase activity. The indicators of COD, TN, TP, and AN, which are collected in real time through the online water quality monitoring system, can be input into the evaluation model to directly obtain the evaluation results of the activity level.

[0060] For reference only, see Figure 2 and Figure 3 As shown, the above wastewater treatment methods can utilize a wastewater treatment acclimatization system, as referenced. Figure 2 As shown, the wastewater treatment acclimatization system includes a reaction vessel 1, which contains a water distribution assembly 2 and a biological packing assembly 3. The biological packing assembly 3 is positioned above the water distribution assembly 2, and a water distribution zone is formed between the water distribution assembly 2 and the bottom of the reaction vessel 1. The aeration pipe 4 is positioned in the water distribution zone. An inlet tank 5 is provided on one side of the reaction vessel 1, and a return pipe 6 is provided on the inlet tank 5. The return pipe 6 is connected to the upper part of the reaction vessel 1. Wastewater treatment is carried out by the reaction vessel 1.

[0061] Furthermore, the water distribution assembly 2 includes a peristaltic pump 7 and a water distribution pipe 8. The input side and output side of the peristaltic pump 7 are respectively connected to 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. The water distribution pipe 8 is provided with several output holes. The return pipe 6 is provided with a return valve 9, which controls the flow state of the return pipe 6.

[0062] The reaction zone of the aforementioned reaction vessel 1 has a height-to-diameter ratio of 8:1. A drain pipe 10 is installed at the top of the reaction vessel 1 to drain the supernatant from it. The 8:1 height-to-diameter ratio design is beneficial for electrode distribution and electric field uniformity. By designing a higher reaction zone, a more uniform electric field distribution between the electrode wires can be ensured, thereby improving the electron transfer efficiency in the wastewater. Simultaneously, the higher reaction zone reduces water flow turbulence and maintains water flow stability, ensuring sufficient retention time of wastewater in the reactor, promoting the degradation of organic matter and nitrogen removal, and avoiding dead zones or poor flow.

[0063] The reaction vessel 1 has a first electrode 11 vertically arranged inside and several second electrodes 12 distributed around the first electrode. The first electrode 11 and the second electrode 12 are connected to an external power supply device 13, which adjusts the voltage environment in the reaction vessel 1 through the first electrode 11 and the second electrode 12.

[0064] The power supply equipment needs to be able to control the output current and set the voltage value required for the experiment. Therefore, existing products can be selected, such as the ASR-2000 series programmable AC / DC power supply and the Mean Well LRS-150 adjustable power module, to meet the requirements of 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 embodiments. The sludge and wastewater are selected from an SBR tank in a wastewater treatment plant. Spherical packing with a particle size of 3-6 mm is used for the iron-carbon packing. An plexiglass tube is selected as the reaction vessel, ensuring an effective volume of 6000 ml. The reactor is cylindrical with an inner diameter of 10 cm and a total height of 90 cm. The height-to-diameter ratio of the reaction zone is 8:1. From bottom to top, the reaction zone consists of an aeration pipe, a water distribution zone, and the reaction zone. Seven stainless steel wire electrodes are vertically arranged around the perimeter of the reaction zone, and one stainless steel wire electrode is vertically arranged in the center to simulate the second electrode 12 and the first electrode 11. The power supply equipment can be an existing AC / DC energy storage power supply, such as the HNAT-6000A portable energy storage power supply or similar products.

[0066] Purchased anaerobic ammonia oxidizing bacteria granular sludge was inoculated into a 2500ml glass bottle. The volume of the anaerobic ammonia oxidizing bacteria granular sludge was 400ml, labeled as sample 8252#. Anaerobic culture was performed, and samples were collected for analysis. The parameters of sample 8252# within the following periods were obtained as follows:

[0067] Sample number / analysis date COD TP TN AN 8252# as is / 230831 197.64 1.26 95.22 89.26 8252# as is / 230901 39.53 1.08 80.11 78.11

[0068] Preliminary analysis showed that the total nitrogen removal rate of the sludge was 93.75 gN / m³·d, and the activity of the original sludge sample #8252 was not high. Therefore, the wastewater was adjusted and fed into the first wastewater treatment plant for further anaerobic culture and sampling analysis, yielding the following data:

[0069] Sample number / analysis date COD TP TN AN 8252# as is / 230907 185.32 1.15 191.81 130.49 8252# as is / 230908 42.67 0.98 108.09 96

[0070] The above data shows that the nitrogen load (NRR) of the anaerobic ammonia-oxidizing bacteria granular sludge is 523.25 gN / m3.d, which is achieved by anaerobic cultivation of the sludge until the activity of the sludge is restored from the first wastewater treatment.

[0071] Subsequently, 10g of iron and carbon were added, and the wastewater was adjusted to become the second wastewater for cultivation, designated as sample replacement #8252. During the cultivation process, the water was changed regularly to prevent salinity increases from affecting sludge acclimatization. Anaerobic ammonia-oxidizing bacteria, a bacterial companion, a bacterial growth promoter, FMBR composite bacteria, and anaerobic sludge were added during the cultivation and acclimatization process. Adjustments were made gradually throughout the cycle, and monitoring was conducted, with the sample replacement designated as sample replacement #8252. The sampling results for sample replacement #8252 are as follows:

[0072] Sample number / analysis date COD TP TN AN 8252# Sample Replacement / 240418 892.5 13.35 245.2 152 8252# Sample Replacement / 240419 849 13.08 143 146.9

[0073] The above data shows that the nitrogen load (NRR) of the anaerobic ammonia-oxidizing bacteria granular system (700 ml sludge volume) is 365.0 gN / m³.d, indicating that the sludge nitrogen load is acceptable and the sludge's tolerance to COD is improved. After the sludge pre-cultivation is complete, sample #8252 was used as the second batch of sludge for subsequent sludge acclimatization.

[0074] Based on the foregoing embodiments, in order to confirm the effectiveness of the test treatment method, one embodiment of the present invention is to conduct a wastewater treatment experiment.

[0075] The sludge used in the experiment came from the SBR tank of a wastewater treatment plant. The sludge had good activity, was yellowish-brown and flocculent, with an SV30 of 31.5%. The MLSS of the inoculated SBR sludge was 4000 mg·L⁻¹. Iron-carbon was added at a concentration of 10 g / L, with an elemental iron content of 60%. Polyurethane foam packing material was added, with a total volume of 2 L, sample number 920 (Lingang sludge culture), and the pH was adjusted to 7.2.

[0076] Among them, sample number 920, the sludge cultured at the port, was used as the reaction sludge, and its parameters are as follows:

[0077] Sample number / analysis date COD TP TN AN 920 Lingang sludge cultivation / 240923 94.87 5.42 155.39 139.39

[0078] The adjusted wastewater was pumped to the mark, and the reaction was carried out according to the following schedule: 15 minutes of influent, 3.0 hours of aeration, 8.5 hours of sedimentation, and 15 minutes of effluent, for a total of 12 hours. Two cycles were performed daily, and samples were collected and analyzed once daily. The following data were obtained:

[0079] Sample number / analysis date COD TP TN AN 920 Lingang sludge cultivation / 240930 39.53 2.18 50.61 40.50

[0080] Based on the evaluation of the cultivation data, the sludge activity was normal, and the wastewater was adjusted to proceed to the next step. Sludge sample 920 (Lingang) was placed in an electric field environment. Initially, the electric field environment was set to DC power at 0.5V, with seven peripheral stainless steel wire electrodes connected to the positive terminal and one central stainless steel wire electrode connected to the negative terminal. Two cycles were continued daily, with the voltage increased by 0.1V each time based on the cultivation data, and samples were taken and analyzed once daily. During the cultivation process, 100ml of a second batch of sludge (sample 8252#) was added daily for combined processing. The reaction was carried out, and after 12 cycles, the pretreatment was completed, and the sludge parameters were obtained as follows:

[0081]

[0082]

[0083] The above sludge parameters remained stable and activity was normal throughout the day. The next step involved outputting AC power at 1.2V and 0.4Hz. A circuit was formed by the seven peripheral stainless steel wire electrodes and the central stainless steel wire electrode. Two reaction cycles were performed daily, with sampling and analysis conducted once daily. The following data were obtained:

[0084] Sample number / analysis date COD TP TN AN 920 Lingang sludge cultivation / 241025 158.11 2.016 24.49 26.13

[0085] After evaluation of the culture data, the sludge activity was found to be normal, and the wastewater was then adjusted for the next step. The direct current was switched to alternating current for output, with the voltage set at 1.2V and the frequency at 0.4Hz. A circuit was formed by seven peripheral stainless steel wire electrodes and one central stainless steel wire electrode. The cycle was set as follows: 15 minutes of influent, 3.0 hours of aeration, 8.5 hours of sedimentation, and 15 minutes of effluent, for a total of 12 hours. Two cycles were performed daily. Based on the culture data, the aeration time was reduced by 30 minutes and the sedimentation time increased by 30 minutes each time. Samples were taken and analyzed daily until aeration was discontinued.

[0086] Sample number / analysis date COD TP TN AN 920 Lingang sludge cultivation / 241129 223.93 0.692 4.01 3.74

[0087] Based on the evaluation of the cultivation data, the sludge activity was normal, and the sludge electro-acclimation was completed.

[0088] To verify the stability of the AC-powered biological wastewater treatment technology, an operational experiment was conducted. The reflux valve was opened, the outlet valve was closed, the air pump was turned off, the water sample was adjusted, the peristaltic pump was turned on, and the power was switched on. The frequency was set to 0.4Hz, the voltage to 1.2V, and the current to 26mA, and the water sample was circulated for treatment. Sampling tubes from a BEW-AN100 ammonia nitrogen water quality automatic online monitoring instrument and a BEW-TN100 total nitrogen water quality automatic online monitoring instrument were placed in the influent tank, and the system was set to analyze once daily. The following parameters were obtained:

[0089]

[0090]

[0091] Based on the above data, the nitrogen load (NRR) of the anaerobic ammonia-oxidizing bacteria granular system (1900 ml sludge volume, 25 L wastewater volume) is approximately 39.5 gN / m³.d. The system's nitrogen load is relatively low, and further cultivation and acclimatization are needed to improve its nitrogen load capacity. For subsequent research, gradient experiments should be conducted at different sludge concentrations (MLSS) ranging from 3000 to 8000 mg / L. This will facilitate the later investigation of the quantitative relationship between the additive dosage (0.5%-2.5%) and sludge settling performance (SV30). Simultaneously, the synergistic effects of dissolved oxygen (DO) > 2 mg / L and temperature (20-30℃) need to be monitored. Experimental data show that when the additive dosage is 1.2%, the specific oxygen consumption rate (SOUR) of the sludge can be increased by 35%, and the denitrification efficiency reaches its optimal level.

[0092] It should be noted that this invention can also be combined with existing UASB upflow anaerobic sludge blanket, activated sludge process, biofilm process and other combined applications, which can facilitate the upgrading and transformation of existing sewage treatment plants.

[0093] In this specification, terms such as "one embodiment," "another embodiment," "embodiment," etc., refer to specific features, structures, or characteristics described in connection with that embodiment, which are included in at least one embodiment described in the general description of this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in connection with any embodiment, it is intended to suggest that implementing such a feature, structure, or characteristic in conjunction with other embodiments also falls within the scope of this invention.

[0094] Although the invention has been described herein with reference to several illustrative embodiments, it should be understood that many other modifications and implementations can be devised by those skilled in the art, which will fall within the scope and spirit of the principles disclosed herein. More specifically, various variations and modifications can be made to the components and / or layout of the subject matter arrangement within the scope of the disclosure, drawings, and claims. Besides variations and modifications to the components and / or layout, other uses will be apparent to those skilled in the art.

Claims

1. A wastewater treatment method, characterized in that, The method includes the following steps: Configure the electric field environment: A first electrode is vertically placed inside the reaction vessel, and several second electrodes are distributed around the first electrode. The first and second electrodes are connected to an external power supply device, and the power supply device establishes an electric field environment in the reaction vessel through the first and second electrodes. Sludge acclimatization: Wastewater is introduced into the reaction vessel and biological packing material is added; Activated sludge is obtained by acclimating sludge in an electric field environment; Anaerobic treatment: The acclimated activated sludge is fed into the reaction vessel; wastewater is continuously fed into the reaction vessel for anaerobic wastewater treatment. During anaerobic wastewater treatment, the reaction vessel is placed in an electric field environment, and the biofilm and activated sludge on the biological packing material will form several microcathodes and microanodes; the microcathodes act as electron donors and provide electrons required for denitrification and gasification phosphorus removal; the microanodes act as electron acceptors and receive electrons released from nitrification, nitrite, and anaerobic ammonia oxidation. When acclimating activated sludge using an electric field environment, a preset acclimation period is established. During this period, the power supply equipment gradually adjusts the electric field environment within the reaction vessel. Direct current is output to the wastewater in the reaction vessel through the second and first electrodes. Wastewater parameters are then acquired, and the voltage is gradually increased based on these parameters until the activity in the sludge stabilizes. After this, the direct current is converted to alternating current for output. Wastewater parameters are continuously collected to ensure the sludge maintains its activity. The aeration rate is then gradually reduced. The reaction vessel operates in a fully anaerobic environment, replacing the aerobic reaction, eliminating the need for aeration.

2. The wastewater treatment method according to claim 1, characterized in that: Before acclimation of the sludge, sludge cultivation is also included, which is used to adjust the sludge properties; specifically, it includes the following steps: Anaerobic ammonia-oxidizing bacteria granular sludge was inoculated into a reaction vessel and the first wastewater was added. The wastewater was anaerobically cultured until the judgment conditions were met, so that the activity of the sludge was restored and the first sludge was obtained. 2 g / L of iron and carbon was added to the reaction vessel, and the first wastewater was added. The conditions for determination were met through anaerobic culture to obtain the second sludge. The second sludge was used for acclimatization in an electric field environment. The criteria for judgment are that the current wastewater indicators are lower than the second wastewater indicators, and the second wastewater is the wastewater after two cycles of sludge cultivation of the first wastewater.

3. The wastewater treatment method according to claim 2, characterized in that: During sludge cultivation, current wastewater parameters are periodically monitored, and active additives are added to the wastewater. These active additives include one or more of the following: anaerobic ammonia-oxidizing bacteria, bacterial companions, bacterial growth promoters, FMBR composite bacteria, anaerobic sludge, and SBR sludge. The active additives maintain the judgment conditions during the sludge cultivation process.

4. The wastewater treatment method according to claim 2, characterized in that: During sludge cultivation, the parameters of the first wastewater 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. The first sludge exhibits a Ma content of over 40%, a Me content of over 60%, and a Mi content of over 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 wastewater treatment method according to claim 1, characterized in that: The process of acclimating activated sludge through an electric field environment includes the following steps: S100: Determine the concentration of the reacting sludge, and select iron-carbon with an elemental iron content of 60% as the microbial electro-acclimation medium; when introducing wastewater into the reaction vessel; set the influent time, aeration time, sedimentation time, and drainage time in sequence to form a reaction cycle.

6. The wastewater treatment method according to claim 5, characterized in that: The process of acclimating activated sludge through an electric field environment includes the following steps: S200, a preset acclimatization period, wherein the acclimatization period includes several reaction periods; S300: Data sampling and counting are conducted during the acclimatization period, with the time interval between two adjacent data samplings being greater than 12 hours; the activity of the current sludge is measured through sampling. If, after any data sampling, the sludge is determined to lack activity, the composition of the wastewater is readjusted and the count is reset to zero; if after N samplings, where N is a positive integer and N≥7, the sludge is considered to maintain activity.

7. The wastewater treatment method according to claim 6, characterized in that: The process of acclimating activated sludge through an electric field environment also includes the following steps: S400, the power supply equipment gradually adjusts the electric field environment in the reaction vessel during the acclimation period; before each adjustment of the electric field environment, sampling is used to determine whether the current sludge maintains its activity. If activity is lost, maintain the current electric field environment and add an activation aid to restore sludge activity; If the activity is to be maintained, the aeration rate of the aeration pipes will be gradually reduced during the acclimatization period based on the wastewater index data.

8. The wastewater treatment method according to claim 7, characterized in that: The process of acclimating activated sludge through an electric field environment also includes the following steps: S500: When the aeration rate approaches zero, check the activity level of the activated sludge. If the activity level is normal, the electrobiological acclimatization is completed and activated sludge is obtained.

9. The wastewater treatment method according to claim 7, characterized in that: The second and first electrodes output direct current to the wastewater in the reaction vessel, with the output voltage set at 0.5V and gradually increased according to the wastewater parameters. The direct current is then converted to alternating current for output, with the alternating current voltage configured at 1.2V and the frequency at 0.4Hz.

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