Method for enhancing biological phosphorus removal and application

Abstract

The invention provides a method for enhancing biological phosphorus removal and application. The method comprises the following steps: providing a sulfate solution; adding the sulfate solution into a water inlet zone or an anaerobic zone of a sewage treatment system to obtain a mixed solution; carrying out biological phosphorus removal operation treatment on the mixed solution; wherein the sulfate solution comprises SO4 < 2->; the concentration of SO4 < 2-> in the mixed solution is 50-200mg / L; the sewage treatment system comprises a reactor running in an anaerobic-aerobic alternate mode and a microbial community; the microbial community comprises glycogen accumulating bacteria (GAOs) and phosphorus accumulating bacteria (PAOs). The method is easy and convenient to operate, has the advantages of being environmentally friendly, controllable in cost, high in applicability and the like, has good generalizability and industrial suitability, and has wide application prospects.

Description

Technical Field

[0001] This invention relates to the field of high-phosphorus wastewater treatment technology, and in particular to a method and application for enhanced biological phosphorus removal. Background Technology

[0002] Currently, most wastewater treatment plants employ a combined phosphorus removal process: "front-end biological phosphorus removal" plus "back-end chemical precipitation." Biological phosphorus removal, as the core component, relies on polyphosphate-accumulating organisms (PAOs) to remove phosphorus through a "phosphorus release-phosphorus uptake" metabolism in an alternating anaerobic-aerobic environment. However, in actual operation, glucan-producing bacteria (GAOs) and PAOs directly compete for carbon sources and niche dominance. While GAOs can absorb and store carbon sources as internal sources, they lack the ability to accumulate phosphorus. Their excessive proliferation leads to insufficient available carbon sources for PAOs and suppressed metabolic activity, ultimately causing biological phosphorus removal efficiency to drop below 60%, significantly weakening the system's resistance to shock loads, and resulting in frequent fluctuations in total phosphorus in the effluent.

[0003] To meet increasingly stringent emission standards, wastewater treatment plants have been forced to increase the dosage of downstream chemical agents (such as polyaluminum chloride and ferrous sulfate) to compensate for the efficiency gap in biological phosphorus removal. However, excessive chemical dosage not only drives up treatment costs but also increases sludge production by more than 30%, exacerbating the burden of subsequent sludge dewatering and disposal. Furthermore, chemical residues may affect the ecological safety of the effluent, contradicting the current upgrade requirements of wastewater treatment plants for "low-carbon operation and cost reduction and efficiency improvement." There is an urgent need to develop a novel strategy that requires no additional organic carbon source and allows for precise control of the microbial community structure. By strengthening the competitive advantage of PAOs and inhibiting the excessive growth of GAOs, this strategy can improve the stability and efficiency of the biological phosphorus removal system from the source, reduce the dosage of downstream chemical agents, and promote the upgrade of wastewater treatment processes towards low-carbon, high-efficiency, and eco-friendly directions. Summary of the Invention

[0004] The main objective of this invention is to provide a method and application for enhanced biological phosphorus removal, aiming to solve the technical problems of large sludge volume and high treatment cost in existing high-phosphorus wastewater phosphorus removal treatment.

[0005] To achieve the above objectives, the present invention provides a method for enhanced biological phosphorus removal, comprising the following steps: S1: Provide sulfate solution.

[0006] S2: The sulfate solution is added to the influent zone or anaerobic zone of the wastewater treatment system to obtain a mixed solution.

[0007] S3: Perform biological phosphorus removal treatment on the mixed solution.

[0008] The sulfate solution contains SO4. 2- .

[0009] SO4 in the mixed solution 2- The concentration is 50~200mg / L.

[0010] The wastewater treatment system includes a reactor and a microbial community that operate in an alternating anaerobic-aerobic mode.

[0011] The microbial community includes polysaccharide-producing bacteria (GAOs) and polyphosphate-producing bacteria (PAOs).

[0012] According to embodiments of this application, the sulfate solution includes water-soluble sulfate.

[0013] The sulfate solution includes one or more of sodium sulfate solution, magnesium sulfate solution, and calcium sulfate solution.

[0014] According to an embodiment of this application, the SO4 in the mixed solution is determined based on the total phosphorus concentration and carbon-to-phosphorus ratio of the influent. 2- The concentration is controlled in stages, including: When the total phosphorus concentration in the influent is <10 mg / L and the carbon-to-phosphorus ratio (C / P) is ≥20, the SO4 content in the mixed solution is... 2- The concentration is 100 ~ 200 mg / L.

[0015] When the total phosphorus concentration in the influent is ≥10 mg / L and the carbon-to-phosphorus ratio (C / P) is <20, the SO4 content in the mixed solution is... 2- The concentration is 50 ~ 150 mg / L.

[0016] According to an embodiment of this application, the operation of the reactor includes a sequentially cyclical anaerobic phase and an aerobic phase.

[0017] Between the anaerobic stage and the aerobic stage, there is also an anoxic stage.

[0018] Following the aerobic stage, there are also a sedimentation stage and an effluent stage.

[0019] The duration of the periodic cycle is 10-15 hours.

[0020] According to the embodiments of this application, the duration of the anaerobic phase is 120~240 min.

[0021] The duration of the aerobic phase is 120-240 minutes.

[0022] The hypoxic phase lasts for 120-210 minutes.

[0023] The precipitation stage lasts for 30 to 90 minutes.

[0024] According to an embodiment of this application, the dissolved oxygen concentration in the aerobic stage is 0.1~2.5 mg / L.

[0025] According to the embodiments of this application, the duration of the biological phosphorus removal operation is ≥60 days.

[0026] The reactor includes one of the following: sequencing batch reactor (SBR), membrane bioreactor (MBR), and continuous flow anaerobic-anoxic-aerobic process reactor.

[0027] According to embodiments of this application, the polyphosphate-accumulating bacteria (PAOs) include Dechloromonas , Thiobacillus , Thauera , Thiothrix, Candidatus Promineifilum One or more of them.

[0028] The present invention also provides an application of the enhanced biological phosphorus removal method described above in the treatment of high-phosphorus wastewater, wherein the total phosphorus concentration in the high-phosphorus wastewater is 8~12 mg / L.

[0029] The mass concentration of suspended solids in the high-phosphorus wastewater is 3000~4000 mg / L.

[0030] According to embodiments of this application, the sources of the high-phosphorus wastewater include municipal sewage or industrial wastewater.

[0031] The removal rate of total phosphorus in the high-phosphorus wastewater is ≥80%.

[0032] The total phosphorus concentration in the effluent of the wastewater treatment system is <2 mg / L.

[0033] The beneficial effects achieved by this invention are as follows: The enhanced biological phosphorus removal method provided by this invention involves adding an appropriate amount of sulfate (50-200 mg / L) to the wastewater treatment system and using a reactor that operates in alternating anaerobic and aerobic modes. This allows for the partial reduction of sulfate in the wastewater treatment system under anaerobic conditions, generating sulfides, elemental sulfur, and sulfur-containing intermediates. This effectively inhibits the excessive proliferation of polyphosphate-accumulating organisms (GAOs) while selectively promoting the accumulation of polyphosphate-accumulating organisms (PAOs), thereby significantly improving the total phosphorus removal efficiency of the system. This method is simple to operate, requires no changes to the existing wastewater treatment process or the construction of a dedicated reactor, and has advantages such as being environmentally friendly, cost-effective, and highly applicable.

[0034] Compared with the traditional "biological phosphorus removal" coupled with "chemical precipitation" process, this enhanced biological phosphorus removal method does not require the addition of large amounts of chemical agents such as iron salts and aluminum salts, which reduces sludge production and operating costs from the source, while avoiding the risk of secondary pollution caused by excessive chemical agents.

[0035] This enhanced biological phosphorus removal method, when applied to the treatment of high-phosphorus wastewater, can efficiently remove total phosphorus from such wastewater. It possesses good scalability and industrial adaptability, and can be used in new wastewater treatment systems as well as as an enhancement measure for upgrading existing wastewater treatment plants, demonstrating broad application prospects. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the structure of a conventional sequencing batch reactor (SBR) according to Embodiment 1 of the present invention; Figure 2 This is a graph showing the long-term average effluent phosphorus concentration of a conventional sequencing batch reactor in Example 1 of the present invention. Figure 3 This is a relative abundance distribution map of polyphosphate-accumulating bacteria, polysaccharide-accumulating bacteria, denitrifying bacteria, sulfur-metabolizing bacteria, and other bacterial groups in the blank group and hypoxia experimental group of Example 1 of the present invention (based on metagenomic analysis).

[0038] The realization of the objective, functional characteristics and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0039] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0041] To achieve the above objectives, the present invention provides a method for enhanced biological phosphorus removal, comprising the following steps: S1: Provide a sulfate solution; the sulfate solution includes SO4. 2- .

[0042] In some embodiments, the sulfate solution can provide a suitable concentration of SO4 for functional microorganisms such as polyphosphate-accumulating bacteria and polysaccharide-accumulating bacteria in the biological phosphorus removal system. 2- This ensures the normal metabolic activity of microorganisms and avoids metabolic limitations caused by excessively low substrate concentrations, thus ensuring the effective functioning of phosphorus removal from the root. It also prevents osmotic pressure stress, microbial community imbalance, and the inhibition of phosphorus removal function caused by excessive sulfate at high concentrations, as well as the accumulation of sulfides, thereby stabilizing and maintaining the efficient operation of the biological phosphorus removal system.

[0043] In some embodiments, the sulfate solution is a sodium sulfate (Na2SO4) solution, and the dosage is 0.1~0.25 g / L based on Na2SO4.

[0044] S2: The sulfate solution is added to the influent zone or anaerobic zone of the wastewater treatment system to obtain a mixed solution. The mixed solution contains SO42-. 2- The concentration is 50~200mg / L.

[0045] In some embodiments, SO4 in the mixed solution 2- The concentration is 75~200mg / L.

[0046] In some embodiments, SO4 in the mixed solution 2- The concentration is 50~100mg / L.

[0047] In some embodiments, SO4 in the mixed solution 2- The concentration is 100~200mg / L.

[0048] S3: Perform biological phosphorus removal treatment on the mixed solution.

[0049] The wastewater treatment system includes a reactor and a microbial community that operate in an alternating anaerobic-aerobic mode.

[0050] The microbial community includes polysaccharide-producing bacteria (GAOs) and polyphosphate-producing bacteria (PAOs).

[0051] In some embodiments, adding sulfate solution to the influent zone or anaerobic zone of a wastewater treatment system can release SO4 in the core metabolic region of the microbial community (polysacchariform bacteria, polyphosphate-accumulating bacteria). 2- This ensures that the substrate can be captured and utilized by functional microorganisms in a timely manner, providing a sufficient material basis for key metabolic processes such as phosphorus release by polyphosphate-accumulating bacteria and glycogen synthesis by polysaccharide-accumulating bacteria during the anaerobic stage, thus enhancing the initial start-up effect of biological phosphorus removal. The wastewater treatment system adopts an anaerobic-aerobic alternating operation mode, and this dosing method matches the anaerobic-aerobic alternation cycle of the process, ensuring SO4 levels are controlled. 2-During the anaerobic stage, the system fully participates in the metabolic reactions of functional microorganisms, avoiding substrate loss or ineffectiveness due to dosing site deviation, thus improving substrate utilization. Under these conditions, sulfate in the system is partially reduced during the anaerobic / anoxic stage, generating sulfides, elemental sulfur, and sulfur-containing intermediates, which can effectively inhibit the growth of... Competibacter, Contendobacter, Defluviicoccus The overgrowth of GAOs (glycan-producing bacteria) and the selective promotion of the growth of GAOs (glycan-producing bacteria) Dechloromonas, Thiothrix, Thauera This method enriches polyphosphate-accumulating bacteria (PAOs) and optimizes the microbial community structure. Therefore, this enhanced biological phosphorus removal method does not require the addition of additional organic carbon sources, making it particularly suitable for low-carbon wastewater treatment scenarios with limited carbon sources or unbalanced C / P ratios, and possesses good engineering adaptability and promotion potential.

[0052] In some embodiments, the wastewater treatment system adopts an alternating anaerobic-aerobic or anaerobic-anoxic-aerobic operation mode.

[0053] The aforementioned enhanced biological phosphorus removal method precisely controls the SO4 concentration in the mixed solution by adding appropriate amounts of sulfate to the wastewater treatment system. 2- The concentration of the active ingredient is 50~200 mg / L, and it is used in conjunction with a reactor that operates in alternating anaerobic and aerobic modes. This allows for the partial reduction of sulfate in the wastewater treatment system under anaerobic conditions, generating sulfides, elemental sulfur, and sulfur-containing intermediates. This effectively inhibits the excessive proliferation of polysaccharide-accumulating organisms (GAOs) and selectively promotes the accumulation of polyphosphate-accumulating organisms (PAOs), thereby effectively improving the total phosphorus removal efficiency of the system. Compared with the traditional "biological phosphorus removal" coupled with "chemical precipitation" process, this enhanced biological phosphorus removal method does not require the addition of large amounts of iron salts, aluminum salts, and other chemical agents, reducing sludge production and operating costs at the source, while avoiding the risk of secondary pollution caused by excessive chemical agents.

[0054] In some embodiments, the sulfate solution comprises water-soluble sulfate.

[0055] The sulfate solution includes one or more of sodium sulfate solution, magnesium sulfate solution, and calcium sulfate solution.

[0056] In some embodiments, the sulfate solution includes one of sodium sulfate solution, magnesium sulfate solution, and calcium sulfate solution.

[0057] In some embodiments, the sulfate solution includes a sodium sulfate solution.

[0058] In some embodiments, water-soluble sulfates exhibit good solubility and dispersibility in water, ensuring that sulfate components can fully participate in the reaction process, achieving complete release of sulfate ions, and increasing SO42- content. 2- -S's bioavailability and reaction efficiency ensure that the nutritional needs of microbial metabolic processes are met.

[0059] In some embodiments, the SO4 in the mixed solution is determined based on the total phosphorus concentration and carbon-to-phosphorus ratio of the influent. 2- The concentration is controlled in stages, including: When the total phosphorus concentration in the influent is <10 mg / L and the carbon-to-phosphorus ratio (C / P) is ≥20, the SO4 content in the mixed solution is... 2- The concentration is 100 ~ 200 mg / L.

[0060] When the total phosphorus concentration in the influent is ≥10 mg / L and the carbon-to-phosphorus ratio (C / P) is <20, the SO4 content in the mixed solution is... 2- The concentration is 50 ~ 150 mg / L.

[0061] In some embodiments, during operation, the concentration of sulfate solution added is adjusted upward or downward according to the total phosphorus concentration and carbon-to-phosphorus ratio of the influent.

[0062] In some embodiments, the SO4 in the mixed solution is determined based on the total phosphorus concentration and carbon-to-phosphorus ratio of the influent. 2- The concentration is controlled in stages, including: When the total phosphorus concentration in the influent is 8-10 mg / L and the carbon-to-phosphorus ratio (C / P) is ≥20, the SO4 content in the mixed solution is... 2- The concentration is 150 ~ 200 mg / L.

[0063] When the total phosphorus concentration in the influent is 10-12 mg / L and the carbon-to-phosphorus ratio (C / P) is ≤15 (relatively insufficient carbon source), the SO4 content in the mixed solution is... 2- The concentration is 50 ~ 100 mg / L.

[0064] In some embodiments, when the total phosphorus concentration in the influent is 10-12 mg / L and the carbon-to-phosphorus ratio (C / P) is 15-20, the SO4 content in the mixed solution is... 2- The concentration is 100~150 mg / L.

[0065] In some embodiments, when the total phosphorus in the effluent increases or fluctuates during operation, the sulfate concentration can be increased by one level within the range of the above-mentioned graded control; when the total phosphorus in the effluent is continuously and stably maintained at a low level, the sulfate concentration can be decreased by one level to balance phosphorus removal effect and operating cost.

[0066] In some embodiments, the operation of the reactor includes sequentially cyclical anaerobic and aerobic phases.

[0067] Between the anaerobic stage and the aerobic stage, there is also an anoxic stage.

[0068] Following the aerobic stage, there are also a sedimentation stage and an effluent stage.

[0069] The duration of the periodic cycle is 10-15 hours.

[0070] In some embodiments, the wastewater treatment system adopts an alternating anaerobic-aerobic or anaerobic-anoxic-aerobic operation mode.

[0071] In some embodiments, the duration of the periodic cycle is 11 to 13 hours, preferably 12 hours.

[0072] In some embodiments, the duration of the anaerobic phase is 120-240 minutes.

[0073] The duration of the aerobic phase is 120-240 minutes.

[0074] The hypoxic phase lasts for 120-210 minutes.

[0075] The precipitation stage lasts for 30 to 90 minutes.

[0076] In some embodiments, the duration of the anaerobic phase is 200-240 minutes.

[0077] The duration of the aerobic phase is 160-200 minutes.

[0078] The hypoxic phase lasts for 180-210 minutes.

[0079] The precipitation stage lasts for 40 to 80 minutes.

[0080] In some embodiments, the duration of the anaerobic phase is 220-240 minutes.

[0081] The duration of the aerobic phase is 170-190 minutes.

[0082] The hypoxic phase lasts for 200-210 minutes.

[0083] The precipitation stage lasts for 50-70 minutes.

[0084] In some embodiments, the dissolved oxygen concentration during the aerobic phase is 0.1~2.5 mg / L. Under these conditions, sulfate in the system is partially reduced during the anaerobic / anoxic phase, generating sulfides, elemental sulfur, and sulfur-containing intermediates. This effectively inhibits the excessive proliferation of polysaccharide-accumulating organisms (GAOs) while selectively promoting the enrichment of polyphosphate-accumulating organisms (PAOs), thus optimizing the microbial community structure in the system.

[0085] In some embodiments, the dissolved oxygen concentration during the aerobic phase is 0.1~0.2 mg / L.

[0086] In some embodiments, the dissolved oxygen concentration during the aerobic phase is 0.2~1.0 mg / L.

[0087] In some embodiments, the dissolved oxygen concentration during the aerobic phase is 1.5~2.5 mg / L.

[0088] In some embodiments, the duration of the biological phosphorus removal operation is ≥60 days.

[0089] The reactor includes one of the following: sequencing batch reactor (SBR), membrane bioreactor (MBR), and continuous flow anaerobic-anoxic-aerobic process reactor.

[0090] In some embodiments, the reactor further includes time switches electrically connected to the inlet tank, aeration head, and agitator, respectively. The inlet tank may be equipped with a time switch to achieve on-time control of the synthetic waste liquid delivered from the inlet tank to the reactor. The time switch adopts a 12-hour periodic program control, specifically: Water intake phase: The water intake tank is set to start at 0 o'clock at the beginning of the cycle and continuously deliver 2L of synthetic waste liquid to the reactor for 0.25 hours, and then automatically shuts off after completion.

[0091] Anaerobic stage: After the water intake is completed (i.e., from cycle 0.25 hours to 4.25 hours), the timer switch of the agitator is started and runs continuously for 4 hours, during which the aeration heads are kept closed to maintain the anaerobic environment.

[0092] Anoxic phase: After the anaerobic phase ends (i.e., from cycle 4.25 hours to 7.75 hours), the agitator continues to run for 3.5 hours, and the aeration heads remain closed to maintain the anoxic environment.

[0093] Aerobic phase: After the anoxic phase ends (i.e., cycle 7.75 hours to 10.75 hours), the timer switch of the aeration head is activated and aeration continues for 3 hours, while the agitator runs synchronously to ensure uniform mixing.

[0094] Sedimentation stage: After the aerobic stage ends (i.e., cycle 10.75 hours to 11.75 hours), both the agitator and aeration head are turned off, and the mixture is allowed to settle for 1 hour.

[0095] Effluent stage: After sedimentation is completed (i.e., cycle 11.75 hours to 12.00 hours), the effluent control component (such as a timer switch electrically connected to the effluent valve) is activated, and 2L of mixed liquid is discharged from the reactor for 0.25 hours. After completing one cycle, it automatically enters the next 12-hour cycle.

[0096] In some embodiments, after more than 60 days of long-term operation, the system establishes a stable microecological system dominated by polyphosphate-accumulating organisms (PAOs), significantly enhancing the biological phosphorus removal function and reducing the amount of downstream chemical reagents required, thus lowering treatment costs. Specifically, sulfate concentration and operating parameters can be flexibly adjusted according to the actual water quality characteristics of each reactor, achieving precise control over the system's microbial niche. This results in a more stable phosphorus-removing microbial community structure and more resilient system operation, making it particularly suitable for wastewater treatment scenarios with limited carbon sources and stringent total phosphorus emission standards. Because different reactors have varying hydraulic retention times, sludge concentrations, and mass transfer conditions, it is necessary to adjust the sulfate concentration to maintain the coordinated and stable operation of the sulfur metabolism and biological phosphorus removal processes.

[0097] In some embodiments, when the selected reactor is a sequencing batch reactor (SBR), the concentration of the mixed solution is 50-80 mg / L.

[0098] In some embodiments, when the selected reactor is a membrane bioreactor (MBR), the concentration of the mixed solution is 80~150 mg / L.

[0099] In some embodiments, when the selected reactor is a continuous flow anaerobic-anoxic-aerobic process reactor, the concentration of the mixed solution is 150~200 mg / L.

[0100] In some embodiments, the polyphosphate-accumulating bacteria (PAOs) include Dechloromonas , Thiobacillus , Thauera , Thiothrix, Candidatus Promineifilum One or more of them.

[0101] In some embodiments, the polyphosphate-accumulating bacteria (PAOs) include Dechloromonas , Thiobacillus , Thauera , Thiothrix, Candidatus Promineifilum One of them.

[0102] In some embodiments, the polyphosphate-accumulating bacteria (PAOs) include Dechloromonas , Thiobacillus , Thau era Thiothrix .

[0103] In some embodiments, the GAOs include Competibacter, Contendobacter, Defluviicoccus One or more of them 。

[0104] The enhanced biological phosphorus removal method provided by this invention is simple to operate, requires no changes to the existing wastewater treatment process or the construction of a special reactor, and has the advantages of being green and environmentally friendly, cost-controllable, and highly applicable.

[0105] The present invention also provides an application of the enhanced biological phosphorus removal method described above in the treatment of high-phosphorus wastewater, wherein the total phosphorus concentration in the high-phosphorus wastewater is 8~12 mg / L.

[0106] The mass concentration of suspended solids in the high-phosphorus wastewater is 3000~4000 mg / L.

[0107] In some embodiments, the mass concentration of suspended solids in the high-phosphorus wastewater is 3300~3700 mg / L.

[0108] In some embodiments, functional genes related to biological phosphorus removal and sulfur metabolism are detected by high-throughput sequencing, qPCR or functional gene detection (such as ppk1, ppx, Sqr, dsrA, SoxXY). Under the condition that the total phosphorus concentration in the influent is 8~12 mg / L, the total phosphorus removal rate can be stably reached above 80%, and the total phosphorus in the effluent can be stably controlled below 2 mg / L.

[0109] In some embodiments, the biodegradable organic carbon content (as COD) in high-phosphorus wastewater is ≤300 mg / L, and the carbon-to-phosphorus ratio (C / P) is ≤20.

[0110] In some embodiments, the carbon-to-phosphorus ratio (C / P) includes the mass ratio of the carbon source to the phosphorus source.

[0111] In some embodiments, the source of the high-phosphorus wastewater includes municipal sewage or industrial wastewater.

[0112] The removal rate of total phosphorus in the high-phosphorus wastewater is ≥80%.

[0113] The total phosphorus concentration in the effluent of the wastewater treatment system is <2 mg / L.

[0114] In some embodiments, the total phosphorus removal rate in the high-phosphorus wastewater is 80-95%; the total phosphorus concentration in the effluent of the wastewater treatment system is 0.5-2.0 mg / L.

[0115] This enhanced biological phosphorus removal method, when applied to the treatment of high-phosphorus wastewater, can efficiently remove total phosphorus from such wastewater. It possesses good scalability and industrial adaptability, and can be used in new wastewater treatment systems as well as as an enhancement measure for upgrading existing wastewater treatment plants, demonstrating broad application prospects.

[0116] To further illustrate the present invention, the following examples are provided: Example 1 A method for enhancing biological phosphorus removal includes the following steps: S1: Provide sulfate solution; the sulfate solution is sodium sulfate (Na2SO4) solution, and the dosage is 0.222 g / L based on Na2SO4.

[0117] High-phosphorus wastewater from a municipal wastewater treatment plant was selected. The suspended solids concentration in the high-phosphorus wastewater was 3500±200 mg / L. The components of the high-phosphorus wastewater were: COD 300 mg / L (calculated as sodium acetate), KH₂PO₄ 10 mg / L (calculated as phosphorus), KNO₃ 50 mg / L (calculated as nitrogen), and the remainder was a trace element solution (composition according to conventional formulations). The total phosphorus concentration in the high-phosphorus wastewater was 10 mg / L.

[0118] S2: Sulfate solution is added to the influent zone of the wastewater treatment system to obtain a mixed solution; SO4 in the mixed solution 2- The concentration was 150 mg / L (corresponding to SO42-). 2- -S = 0.050 g / L) S3: The mixed solution is subjected to biological phosphorus removal treatment for 60 days; the wastewater treatment system includes a reactor operating in an anaerobic-aerobic alternating mode and a microbial community; the microbial community includes polysaccharide bacteria (GAOs) and polyphosphate-accumulating bacteria (PAOs).

[0119] See Figure 1 A conventional sequencing batch reactor (SBR) was selected as the reactor for wastewater treatment in Example 1. The SBR reactor operates in alternating anaerobic, anoxic, and aerobic modes with a 12-hour cycle, including an influent stage, an anaerobic stage, an anoxic stage, an aerobic stage, a sedimentation stage, and an effluent stage. The influent stage lasts 15 minutes; the anaerobic stage lasts 240 minutes; the aerobic stage lasts 180 minutes; the anoxic stage lasts 210 minutes; and the sedimentation stage lasts 60 minutes. Each stage is automatically switched via a programmable timer. The influent or anaerobic zone is where sulfate solution is added to ensure that sulfate participates in the microbial metabolic process during the anaerobic / anoxic stages, thereby enhancing the biological phosphorus removal effect.

[0120] The experiments were divided into groups, and the experimental parameters for each group are shown in Table 1. It should be noted that each group of experiments was conducted in triplicate, and the results were averaged.

[0121] The experimental groups are as follows: Control group 1: Conventional biological phosphorus removal process without sulfate enhancement under low nitrate concentration (20 mg / L KNO3) conditions; Control group 2: Conventional biological phosphorus removal process without sulfate enhancement under high nitrate concentration (45 mg / L KNO3) conditions; Experimental group 1: Process using the sulfate enhancement method of this invention under low nitrate concentration (20 mg / L KNO3) conditions; Experimental group 2: Process using the sulfate enhancement method of this invention under low nitrate concentration (20 mg / L KNO3) conditions; Experimental groups 3 and 4: Process using the sulfate enhancement method of this invention under high nitrate concentration (45 mg / L KNO3) conditions.

[0122] Table 1. Experimental parameters for blank group 1, blank group 2, and experimental groups 1-4. Experimental Results and Analysis See Figure 3 The tests showed that the relative abundance of polyphosphate-accumulating bacteria in control group 1 was 3.31%, and the relative abundance of polysaccharide-accumulating bacteria was 25.78%. This indicates that in the control group without sulfate fortification, the bacterial community structure was dominated by polysaccharide-accumulating bacteria (…). Glycogen Accumulating Organisms GAOs (GMOs) as the main component, polyphosphate-accumulating bacteria (PAOs) Phosphorus Accumulating Organisms The typical characteristic of PAOs being inhibited. In contrast, under low concentration nitrate conditions (NO3), - Under conditions of -N = 20 mg / L, in experimental group 1, which employed sulfate enhancement measures, the relative abundance of polyphosphate-accumulating bacteria significantly increased, reaching 23.68%, while the relative abundance of polysaccharide-accumulating bacteria decreased to 4.25%, indicating a shift in the bacterial community structure from "polysaccharide-accumulating bacteria dominant" to "polyphosphate-accumulating bacteria-dominant." Under high nitrate conditions (NO3-), - Under sulfate concentrations of 45 mg / L, the relative abundance of sulfur metabolism-related bacteria in experimental group 3 was 10.79%, while the relative abundance of denitrifying bacteria increased to 14.04%. Polysaccharide-producing bacteria maintained a low abundance level (1.90%), indicating that under sulfate dosage conditions, a synergistic balance between sulfur metabolism, denitrification, and biological phosphorus removal can be achieved. The experimental results demonstrate that sulfate enhancement treatment has a significant impact on the structure of functional microbial communities.

[0123] To investigate the effect of dissolved oxygen (DO) level changes on biological phosphorus removal performance under sulfate-enhanced conditions, three operating conditions (blank group, hypoxia experimental group, and experimental group) were selected for comparative analysis. See [link to relevant documentation]. Figure 2 The specific conditions are as follows: The control group consisted of two subgroups: a blank control group, which operated under conventional biological phosphorus removal conditions without sulfate enhancement and with dissolved oxygen controlled at 2.5 ± 0.5 mg / L during the aerobic phase; a hypoxic experimental group, which used the sulfate-enhanced biological phosphorus removal method of the present invention, adding sulfate solution to the influent zone and simultaneously reducing dissolved oxygen to 1.5 ± 0.5 mg / L during the aerobic phase; and an experimental group, which also used the sulfate-enhanced biological phosphorus removal method of the present invention, adding sulfate solution to the influent zone or anaerobic zone and controlling dissolved oxygen at 2.5 ± 0.5 mg / L during the aerobic phase.

[0124] from Figure 2 As can be seen, the total phosphorus concentration in the effluent of the control group was 5.51 mg / L, indicating poor overall phosphorus removal efficiency. After sulfate enhancement, the total phosphorus concentration in the effluent significantly decreased under both hypoxic and conventional dissolved oxygen conditions. Specifically, the total phosphorus concentration in the experimental group was 3.79 mg / L, and the total phosphorus concentration in the hypoxic experimental group further decreased to 1.77 mg / L. The results show that under sulfate enhancement conditions, adjusting the dissolved oxygen level can further optimize the biological phosphorus removal effect, and a more stable and lower total phosphorus concentration in the effluent can be obtained when operating within the conventional dissolved oxygen range. Tukey multiple comparison tests showed that the total phosphorus concentration in the effluent of both the hypoxic experimental group and the experimental group was significantly lower than that of the control group, indicating that the sulfate-enhanced biological phosphorus removal method of this invention can significantly improve phosphorus removal efficiency under different dissolved oxygen conditions.

[0125] Comparative Example 1 Compared to Example 1, the sulfate solution was changed.

[0126] In Comparative Example 1, no sulfate solution was added; instead, sodium chloride solution was added to the wastewater treatment system at a dosage of 0.183 g / L (based on NaCl). The other steps were the same as in Example 1.

[0127] After operating under the above conditions, the system did not exhibit the same polyphosphate-accumulating and polysaccharide-inhibiting effects as in Example 1. The biological phosphorus removal performance was significantly inferior to that in Example 1, and the total phosphorus in the effluent was difficult to control at a stable low level, thus failing to achieve the enhanced biological phosphorus removal effect described in this invention.

[0128] Comparative Example 2 Compared to Example 1, the SO4 content in the mixed solution was changed. 2- The concentration.

[0129] In Comparative Example 2, the mixed solution contained SO4 2- The concentration was 10 mg / L, and the other steps were the same as in Example 1.

[0130] Due to SO4 in the mixed solution 2-The concentration of sulfur is too low, which cannot provide sufficient sulfur source for the metabolic activities of polyphosphate-accumulating bacteria, making it difficult to achieve targeted enrichment of polyphosphate-accumulating bacteria. At the same time, the competitive inhibition effect on polysaccharide-accumulating bacteria is significantly weakened. The system did not show the same enhanced biological phosphorus removal effect as in Example 1. The biological phosphorus removal performance was significantly worse than in Example 1, and the total phosphorus in the effluent was difficult to be stably controlled at a low level.

[0131] The enhanced biological phosphorus removal method provided by this invention involves adding an appropriate amount of sulfate to the wastewater treatment system to reduce the SO4 content in the mixed solution. 2- The concentration of the active ingredient is 50~200 mg / L, and when used in conjunction with a reactor operating in alternating anaerobic and aerobic modes, sulfate in the wastewater treatment system is partially reduced in anaerobic mode, generating sulfides, elemental sulfur, and sulfur-containing intermediates. This effectively inhibits the excessive proliferation of polysaccharide-accumulating bacteria (GAOs) and selectively promotes the accumulation of polyphosphate-accumulating bacteria (PAOs), thereby effectively improving the total phosphorus removal efficiency of the system. This method is simple to operate, requires no changes to the existing wastewater treatment process or the construction of a dedicated reactor, and has advantages such as being environmentally friendly, cost-effective, and highly applicable.

[0132] Compared with the traditional "biological phosphorus removal" coupled with "chemical precipitation" process, this enhanced biological phosphorus removal method does not require the addition of large amounts of chemical agents such as iron salts and aluminum salts, which reduces sludge production and operating costs from the source, while avoiding the risk of secondary pollution caused by excessive chemical agents.

[0133] This enhanced biological phosphorus removal method, when applied to the treatment of high-phosphorus wastewater, can efficiently remove total phosphorus from such wastewater. It possesses good scalability and industrial adaptability, and can be used in new wastewater treatment systems as well as as an enhancement measure for upgrading existing wastewater treatment plants, demonstrating broad application prospects.

[0134] In summary, the above-described technical solutions of the present invention are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for enhanced biological phosphorus removal, characterized in that, Including the following steps: S1: Provides sulfate solution; S2: The sulfate solution is added to the influent zone or anaerobic zone of the wastewater treatment system to obtain a mixed solution; S3: Perform biological phosphorus removal treatment on the mixed solution; The sulfate solution contains SO4. 2- ; SO4 in the mixed solution 2- The concentration is 50~200 mg / L; The wastewater treatment system includes a reactor and a microbial community operating in an alternating anaerobic-aerobic mode; The microbial community includes polysaccharide-producing bacteria (GAOs) and polyphosphate-producing bacteria (PAOs).

2. The method for enhanced biological phosphorus removal according to claim 1, characterized in that, The sulfate solution includes water-soluble sulfates; The sulfate solution includes one or more of sodium sulfate solution, magnesium sulfate solution, and calcium sulfate solution.

3. The method for enhanced biological phosphorus removal according to claim 1, characterized in that, Based on the total phosphorus concentration and carbon-to-phosphorus ratio of the influent, the SO4 in the mixed solution was determined. 2- The concentration is controlled in stages, including: When the total phosphorus concentration in the influent is <10 mg / L and the carbon-to-phosphorus ratio (C / P) is ≥20, the SO4 content in the mixed solution is... 2- The concentration is 100~200 mg / L; When the total phosphorus concentration in the influent is ≥10 mg / L and the carbon-to-phosphorus ratio (C / P) is <20, the SO4 content in the mixed solution is... 2- The concentration is 50~150 mg / L.

4. The method for enhanced biological phosphorus removal according to claim 1, characterized in that, The operation of the reactor includes a sequential, cyclical anaerobic phase and an aerobic phase. Between the anaerobic stage and the aerobic stage, there is also an anoxic stage; Following the aerobic stage, there are also a sedimentation stage and an effluent stage; The duration of the periodic cycle is 10-15 hours.

5. The method for enhanced biological phosphorus removal according to claim 4, characterized in that, The duration of the anaerobic phase is 120-240 minutes; The duration of the aerobic phase is 120~240 min; The duration of the hypoxic phase is 120-210 minutes; The precipitation stage lasts for 30 to 90 minutes.

6. The method for enhanced biological phosphorus removal according to claim 4, characterized in that, The dissolved oxygen concentration during the aerobic phase is 0.1~2.5 mg / L.

7. The method for enhanced biological phosphorus removal according to claim 1, characterized in that, The duration of the biological phosphorus removal operation is ≥60 days; The reactor includes one of the following: sequencing batch reactor (SBR), membrane bioreactor (MBR), and continuous flow anaerobic-anoxic-aerobic process reactor.

8. The method for enhanced biological phosphorus removal according to claim 1, characterized in that, The polyphosphate-accumulating bacteria (PAOs) include Dechloromonas , Thiobacillus , Thauera , Thiothrix, Candidatus Promineifilum One or more of them.

9. The application of the enhanced biological phosphorus removal method as described in any one of claims 1 to 8 in the treatment of high-phosphorus wastewater, characterized in that, The total phosphorus concentration in high-phosphorus wastewater is 8-12 mg / L; The mass concentration of suspended solids in the high-phosphorus wastewater is 3000~4000 mg / L.

10. The application according to claim 9, characterized in that, The sources of the high-phosphorus wastewater include municipal sewage or industrial wastewater; The removal rate of total phosphorus in the high-phosphorus wastewater is ≥80%; The total phosphorus concentration in the effluent of the wastewater treatment system is <2 mg / L.

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