A method for enhanced biological phosphorus removal by aerobic starvation

Abstract

The present application relates to sewage treatment technical field, specifically, it is a kind of method for strengthening biological phosphorus removal using aerobic starvation.The activated sludge-wastewater mixture after anaerobic and aerobic treatment is inoculated into aerobic environment, and subjected to aerobic starvation treatment, to obtain the activated sludge-wastewater mixture after aerobic starvation treatment;The activated sludge-wastewater mixture after aerobic starvation treatment is subjected to anaerobic treatment and aerobic treatment in turn, to obtain the wastewater of biological phosphorus removal.The method reduces the content of other bacteria by aerobic starvation treatment, increases the abundance of fermentative polyphosphate-accumulating organisms, improves the phosphorus removal capacity of fermentative polyphosphate-accumulating organisms, and makes the activated sludge after strengthening have stronger phosphorus removal and sludge reduction performance in sewage treatment, which can be effectively popularized and applied.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sewage treatment, in particular to a method for enhancing biological phosphorus removal by using aerobic starvation. BACKGROUND

[0002] With the increase of wastewater discharge, the difficulty of treatment is increasing, and the challenge of treating wastewater is also increasing. The existence of excess phosphorus in water bodies will lead to eutrophication. Biological phosphorus removal process, as a relatively low-cost and mature and effective phosphorus removal technology, is widely used by various countries. Therefore, sewage treatment plants often use the metabolic capacity of microorganisms in activated sludge to purify wastewater. Due to the fluctuation of wastewater flow and composition, bacteria will appear in the aerobic starvation condition, and the problems of unstable phosphorus removal efficiency and low removal rate often occur.

[0003] Unlike traditional phosphorus accumulating bacteria, fermentative phosphorus accumulating bacteria are identified as the main phosphorus accumulating bacteria in wastewater, have fermentation metabolic capacity, can maintain cell survival or promote proliferation through fermentation, can ferment organic compounds such as amino acids into small molecules such as volatile fatty acids, reduce the dependence on exogenous volatile fatty acids and improve the phosphorus removal efficiency, and the substances produced by fermentation can be metabolized by themselves and other organisms, and can also store amino acids in the anaerobic stage and consume them in the aerobic stage to optimize the phosphorus removal performance. Therefore, it is of great significance to study how to use aerobic starvation to strengthen the biological phosphorus removal system dominated by fermentative phosphorus accumulating bacteria to improve the performance of wastewater treatment. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a method for enhancing biological phosphorus removal by using aerobic starvation.

[0005] The technical solution of the present application to solve the above technical problem is as follows:

[0006] The present application provides a method for enhancing biological phosphorus removal by using aerobic starvation, comprising the following steps:

[0007] S1, inoculating activated sludge containing fermentative phosphorus accumulating bacteria into an anaerobic environment, then adding wastewater to be treated for anaerobic treatment to obtain an anaerobically treated activated sludge-wastewater mixture; in the activated sludge, the initial abundance of fermentative phosphorus accumulating bacteria is 3.5%-5%;

[0008] S2, moving the anaerobically treated activated sludge-wastewater mixture to an aerobic environment for aerobic treatment to obtain an aerobically treated activated sludge-wastewater mixture;

[0009] S3, inoculating the aerobically treated activated sludge-wastewater mixture into an aerobic environment for aerobic starvation treatment to obtain an aerobically starved activated sludge-wastewater mixture;

[0010] S4, sequentially anaerobically treating and aerobically treating the activated sludge-wastewater mixture after the aerobic starvation treatment, to obtain wastewater with biological phosphorus removal.

[0011] Based on the above technical solution, the application can be further improved as follows.

[0012] Further, in step S3, the concentration of activated sludge in the aerobic environment is 6000-7000 mg / L.

[0013] Further, the dissolved oxygen content in the aerobic environment is greater than or equal to 6 mg / L.

[0014] Further, during the aerobic starvation treatment, no nutrients are introduced into the aerobic environment.

[0015] Further, the time for the aerobic starvation treatment is 9.5-10.5 days.

[0016] Further, after the aerobic starvation treatment is completed, the abundance of the fermentative polyphosphorus bacteria in the activated sludge is 65%-78%.

[0017] Further, in step S1, the concentration of PO4 3- The concentration of P is 4-8 mg / L, and the concentration of chemical oxygen demand COD is 190-210 mg / L.

[0018] Further, in step S1, the anaerobic treatment time is 180-300 min, and the temperature is 19-21℃.

[0019] Further, in step S2, the aerobic treatment reaction time is 120-200 min, and the temperature is 19-21℃.

[0020] Further, in step S4, the anaerobic treatment step is the same as that in step S1, and the aerobic treatment step in step S4 is the same as that in step S1.

[0021] The application has the following beneficial effects:

[0022] (1) The aerobic starvation enhanced biological phosphorus removal method of the application reduces the content of other bacteria species through aerobic starvation treatment, thereby increasing the abundance of fermentative polyphosphorus bacteria.

[0023] (2) The aerobic starvation enhanced biological phosphorus removal method of the application improves the phosphorus removal capacity of fermentative polyphosphorus bacteria, so that the activated sludge after enhancement has stronger phosphorus removal and sludge reduction performance in wastewater treatment.

[0024] (3) The aerobic starvation enhanced biological phosphorus removal method of the present application limits the specific conditions of aerobic starvation treatment, so that the enhancement effect is optimal;

[0025] (4) The aerobic starvation enhanced biological phosphorus removal method of the present application breaks through the concept in the prior art that aerobic starvation has a destructive effect on the wastewater treatment system, and realizes the enhancement of the biological phosphorus removal method and system through appropriate aerobic starvation treatment, which can be effectively popularized and applied. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The flowchart of the aerobic starvation enhanced biological phosphorus removal method of the present application. DETAILED DESCRIPTION

[0027] The principles and characteristics of the present application are described below in conjunction with the accompanying drawings, and the examples are only used to explain the present application and not to limit the scope of the present application.

[0028] As shown in the drawings, Figure 1 The aerobic starvation enhanced biological phosphorus removal method of the present application comprises the following steps:

[0029] S1, inoculating activated sludge containing fermentative polyphosphate-accumulating organisms into an anaerobic environment, and then adding wastewater to be treated for anaerobic treatment to obtain an activated sludge-wastewater mixture after anaerobic treatment; in the activated sludge, the initial abundance of fermentative polyphosphate-accumulating organisms is 3.5%-5%;

[0030] S2, moving the activated sludge-wastewater mixture after anaerobic treatment to an aerobic environment for aerobic treatment to obtain an activated sludge-wastewater mixture after aerobic treatment;

[0031] S3, inoculating the activated sludge-wastewater mixture after aerobic treatment into an aerobic environment for aerobic starvation treatment to obtain an activated sludge-wastewater mixture after aerobic starvation treatment;

[0032] S4, sequentially performing anaerobic treatment and aerobic treatment on the activated sludge-wastewater mixture after aerobic starvation treatment to obtain wastewater for biological phosphorus removal.

[0033] Compared with other functional bacteria in wastewater treatment, fermentative polyphosphate-accumulating organisms do not depend on nutrients in the influent and can utilize excess sludge as a growth substrate, so they have stronger resistance to the conditions of aerobic starvation. The aerobic starvation enhanced biological phosphorus removal method of the present application increases the abundance of fermentative polyphosphate-accumulating organisms through aerobic starvation treatment, and improves the nutrient removal effect and sludge reduction performance in wastewater treatment.

[0034] The aerobic starvation enhanced biological phosphorus removal method of the application breaks the concept that aerobic starvation has a destructive effect on the wastewater treatment system in the prior art, and realizes the enhancement of the biological phosphorus removal method and system through appropriate aerobic starvation treatment.

[0035] The method of the application is particularly suitable for activated sludge with high initial abundance of fermentative polyphosphorus bacteria, and for initial abundance of 3.5%-5%, whether anaerobic starvation or anoxic starvation is used, the abundance improvement effect, the nutrient removal improvement effect and the sludge reduction improvement effect are all lower than that of aerobic starvation.

[0036] Preferably, in step S3, the concentration of the activated sludge in the aerobic environment is 6000-7000 mg / L.

[0037] Preferably, in the aerobic environment, air pump aeration is used to provide oxygen, so that the dissolved oxygen content in the aerobic environment is greater than or equal to 6 mg / L; through aeration to provide oxygen, the oxygen content in the aerobic environment is ensured, and at the same time, the content of dissolved oxygen is ensured to be high, so that the fermentative polyphosphorus bacteria can be in a complete aerobic environment, and sufficient aerobic conditions in the aerobic starvation treatment process are ensured.

[0038] Preferably, during the aerobic starvation treatment, no nutrient substance enters the aerobic environment; in this way, it can be ensured that the fermentative polyphosphorus bacteria cannot obtain additional nutrients at all, and completely use the excess sludge as a growth substrate, so as to realize effective enhancement of the biological phosphorus removal system.

[0039] Preferably, the time of the aerobic starvation treatment is 9.5-10.5 days; this time can ensure the sufficiency of the aerobic starvation, and prevent the problems of low abundance of fermentative polyphosphorus bacteria and poor enhancement effect caused by insufficient treatment time.

[0040] Preferably, after the completion of the aerobic starvation treatment, the abundance of the fermentative polyphosphorus bacteria in the activated sludge is 65%-78%; the fermentative polyphosphorus bacteria with this abundance can realize effective treatment of wastewater.

[0041] In the method of the application, before the aerobic starvation, anaerobic-aerobic treatment is performed on the activated sludge and wastewater, so that the activated sludge is passivated, and the fermentative polyphosphorus bacteria therein are effectively proliferated, which is beneficial to further enhancement subsequently.

[0042] Preferably, in step S1, the concentration of PO4 3- -P in the wastewater to be treated is 4-8 mg / L, and the concentration of chemical oxygen demand COD is 190-210 mg / L; wherein, PO4 3- -P is provided by KH2PO4, and the chemical oxygen demand COD is provided by casein peptone.

[0043] Preferably, in step S1, the anaerobic treatment is performed for 180-300 min at 19-21℃.

[0044] Preferably, in step S2, the aerobic treatment is performed for 120-200 min at 19-21℃.

[0045] In the method of the present application, after the aerobic starvation, the activated sludge and the wastewater are subjected to anaerobic-aerobic treatment, so that the activated sludge and the wastewater are recovered, and the high-abundance fermentation-type PAOs can effectively treat the phosphorus in the wastewater, achieving biological phosphorus removal.

[0046] Preferably, in step S4, the anaerobic treatment is the same as that in step S1, and the aerobic treatment is the same as that in step S1.

[0047] The method of the present application aims to strengthen the biological phosphorus removal system dominated by fermentation-type PAOs under the condition of aerobic starvation, so as to improve the performance of the biological phosphorus removal system and reduce sludge production, thereby providing a new method for stable phosphorus removal in a wastewater treatment plant.

[0048] The present application is described below through specific examples and comparative examples:

[0049] Example 1

[0050] The activated sludge of this example is from a wastewater treatment plant in Beijing Gaobeidian, and the specific steps of this example are as follows:

[0051] (1) The activated sludge containing fermentation-type PAOs is inoculated into the anaerobic section of the reaction tank, and the wastewater is treated for 240 min, the wastewater containing 6 mg / L of PO4 3- -P (provided by KH2PO4) and 190 mg / L of chemical oxygen demand COD (provided by casein peptone), to obtain the activated sludge and wastewater after anaerobic treatment. The initial abundance of fermentation-type PAOs is 3.5%.

[0052] (2) The activated sludge and wastewater after anaerobic treatment are discharged into the aerobic section of the reaction tank, and reacted for 180 min at 19℃, to obtain the activated sludge containing fermentation-type PAOs after aerobic treatment.

[0053] (3) The activated sludge containing fermentation-type PAOs obtained above is subjected to aerobic starvation, the sludge concentration is 6400 mg / L, no nutrient is provided during the starvation period, and an air pump is operated to ensure sufficient aeration, and the starvation is performed for 9.5 d.

[0054] (4) The activated sludge after aerobic starvation and the wastewater are inoculated into the anaerobic section of the reaction tank, and other operations are consistent with the aforementioned anaerobic treatment and aerobic treatment, to recover the activated sludge and complete biological phosphorus removal.

[0055] After the activated sludge recovery, the treated wastewater is detected.

[0056] After the wastewater treatment, the detection shows that the phosphorus removal rate of the effluent is 85%, the chemical oxygen demand (COD) removal rate is 78%, the daily sludge reduction rate compared with before the aerobic starvation is 71.4%, the MLVSS / MLSS is 63%, and the final abundance of the fermentative phosphate-accumulating bacteria is 66.43%.

[0057] Example 2

[0058] The activated sludge of this example is from the Beijing Gaobeidian Wastewater Treatment Plant, and the specific steps of this example are as follows:

[0059] (1) The activated sludge containing fermentative phosphate-accumulating bacteria is inoculated into the anaerobic section of the reaction tank, and the wastewater is treated for 240 min, the wastewater containing 6 mg / L of PO4 3- -P (provided by KH2PO4) and 190 mg / L of chemical oxygen demand COD (provided by casein peptone) to obtain the activated sludge and wastewater after anaerobic treatment. The initial abundance of the fermentative phosphate-accumulating bacteria is 5%.

[0060] (2) The activated sludge and wastewater after anaerobic treatment are discharged into the aerobic section of the reaction tank, and the reaction is carried out for 180 min at a temperature of 20°C to obtain the activated sludge containing fermentative phosphate-accumulating bacteria after aerobic treatment.

[0061] (3) The activated sludge containing fermentative phosphate-accumulating bacteria obtained above is subjected to aerobic starvation, and the sludge concentration is 6400 mg / L. No nutrient is provided during the starvation, and the air pump is operated to ensure sufficient aeration. The starvation is carried out for 10 d.

[0062] (4) The activated sludge after aerobic starvation is inoculated into the anaerobic section of the reaction tank, and other operations are consistent with the aforementioned anaerobic treatment and aerobic treatment to carry out activated sludge recovery and biological phosphorus removal.

[0063] After the activated sludge recovery, the treated wastewater is detected.

[0064] After the wastewater treatment, the detection shows that the phosphorus removal rate of the effluent is 96%, the chemical oxygen demand (COD) removal rate is 80%, the daily sludge reduction rate compared with before the aerobic starvation is 72.8%, the MLVSS / MLSS is 56%, and the final abundance of the fermentative phosphate-accumulating bacteria is 75.26%.

[0065] Example 3

[0066] The activated sludge of this example is from the Beijing Gaobeidian Wastewater Treatment Plant, and the specific steps of this example are as follows:

[0067] (1) The activated sludge containing fermentative PAOs is inoculated into the anaerobic section of the reaction tank, and the wastewater is treated for 240 min, wherein the wastewater contains 6 mg / L of PO4 3- -P (provided by KH2PO4) and 190 mg / L of chemical oxygen demand COD (provided by casein peptone) to obtain the activated sludge and wastewater after anaerobic treatment. The initial abundance of the fermentative PAOs is 4.5%.

[0068] (2) The activated sludge and wastewater after anaerobic treatment are discharged into the aerobic section of the reaction tank, and are treated for 180 min at a temperature of 21°C to obtain the activated sludge containing fermentative PAOs after aerobic treatment.

[0069] (3) The activated sludge containing fermentative PAOs obtained above is subjected to aerobic starvation, and the sludge concentration is 6400 mg / L. No nutrient is provided during the starvation, and an air pump is operated to ensure sufficient aeration. The starvation lasts for 10.5 d.

[0070] (4) The activated sludge after aerobic starvation is inoculated into the anaerobic section of the reaction tank, and other operations are consistent with the aforementioned anaerobic treatment and aerobic treatment to restore the activated sludge and complete biological phosphorus removal.

[0071] After the activated sludge is restored, the treated wastewater is detected.

[0072] After detection, the phosphorus removal rate of the effluent is 88%, the chemical oxygen demand COD removal rate is 78%, the daily sludge reduction rate compared with before aerobic starvation is 71.8%, the MLVSS / MLSS is 60%, and the final abundance of the fermentative PAOs is 66.33%.

[0073] Comparative Example 1

[0074] The difference between this comparative example and Example 2 is that the aerobic starvation lasts for 1 d, and other steps are the same.

[0075] After detection, the phosphorus removal rate of the effluent is 64%, the chemical oxygen demand COD removal rate is 56%, the daily sludge reduction rate compared with before aerobic starvation is 4.46%, the MLVSS / MLSS is 75%, and the final abundance of the fermentative PAOs is 18.7%.

[0076] Comparative Example 2

[0077] The difference between this comparative example and Example 2 is that the aerobic starvation lasts for 5 d, and other steps are the same.

[0078] After the wastewater treatment, the detection showed that the phosphorus removal rate of the effluent reached 73%, the chemical oxygen demand (COD) removal rate was 58%, the daily sludge reduction rate was 42.6% compared with before the aerobic starvation, the MLVSS / MLSS was 68%, and the final abundance of the fermentative polyphosphate-accumulating bacteria was 36.5%.

[0079] Comparative Example 3

[0080] The difference between the present comparative example and Example 2 is that the aerobic starvation lasts for 15 days, and the other steps are the same.

[0081] After the wastewater treatment, the detection showed that the phosphorus removal rate of the effluent reached 69%, the chemical oxygen demand (COD) removal rate was 57.3%, the daily sludge reduction rate was 31.7% compared with before the aerobic starvation, the MLVSS / MLSS was 70%, and the final abundance of the fermentative polyphosphate-accumulating bacteria was 35.2%.

[0082] Comparative Example 4

[0083] The difference between the present comparative example and Example 2 is that the initial abundance of the fermentative polyphosphate-accumulating bacteria is 2%, and the other steps are the same.

[0084] After the wastewater treatment, the detection showed that the phosphorus removal rate of the effluent reached 70%, the chemical oxygen demand (COD) removal rate was 57%, the daily sludge reduction rate was 30% compared with before the aerobic starvation, the MLVSS / MLSS was 68.2%, and the final abundance of the fermentative polyphosphate-accumulating bacteria was 35%.

[0085] Comparative Example 5

[0086] The difference between the present comparative example and Example 2 is that the initial abundance of the fermentative polyphosphate-accumulating bacteria is 8%, and the other steps are the same.

[0087] After the wastewater treatment, the detection showed that the phosphorus removal rate of the effluent reached 75%, the chemical oxygen demand (COD) removal rate was 69%, the daily sludge reduction rate was 52% compared with before the aerobic starvation, the MLVSS / MLSS was 66%, and the final abundance of the fermentative polyphosphate-accumulating bacteria was 48%.

[0088] The treatment parameters and results of the above examples and comparative examples are shown in Table 1.

[0089] Table 1

[0090]

[0091] It can be seen from the above experimental results that the abundance of the fermentation-type phosphorus accumulating bacteria is not high when the aerobic starvation treatment time is too short or too long. Specifically, because the activated sludge and the wastewater have just been subjected to aerobic treatment before the aerobic starvation, when the starvation time is too short, the nutrients in the activated sludge are not completely consumed by various bacteria, so that a certain amount of other bacteria still exist in the activated sludge, thereby reducing the abundance of the fermentation-type phosphorus accumulating bacteria. When the starvation time is too long, the fermentation-type phosphorus accumulating bacteria itself is damaged, resulting in a reduction in the abundance of the fermentation-type phosphorus accumulating bacteria in the activated sludge.

[0092] For example, the aerobic starvation time of the Comparative Example 2 is 5 days, and the final abundance of the fermentation-type phosphorus accumulating bacteria is only 36.5%, and the daily sludge reduction rate is only 42.6%, indicating that the sludge treatment effect of the Comparative Example 2 is poor.

[0093] It can be seen from the Comparative Examples 4 and 5 compared with the Embodiment 2 that when the initial abundance of the fermentation-type phosphorus accumulating bacteria is too high or too low, the effect is poor.

[0094] It can be seen from the experimental results of the above embodiments and comparative examples that the method of the present application can effectively strengthen the biological phosphorus removal system dominated by the fermentation-type phosphorus accumulating bacteria under the aerobic starvation condition, so as to improve the biological phosphorus removal capacity and reduce the sludge production.

[0095] In the description of the present application, it should be noted that the description of the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms is not necessarily for the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0096] The above is only the preferred embodiment of the present application, and does not limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for enhanced biological phosphorus removal by aerobic starvation, characterized in that, The method comprises the following steps: S1, inoculating activated sludge containing fermentative PAOs into an anaerobic environment, adding wastewater to be treated for anaerobic treatment, and obtaining an activated sludge-wastewater mixture after anaerobic treatment; in the activated sludge, the initial abundance of fermentative PAOs is 3.5%-5%; The concentration of PO4 in the wastewater to be treated 3- - the concentration of P is 4-8 mg / L and the concentration of chemical oxygen demand COD is 190-210 mg / L; The anaerobic treatment time is 180-300 min, and the temperature is 19-21℃; S2, moving the activated sludge-wastewater mixture after anaerobic treatment to an aerobic environment for aerobic treatment, and obtaining an activated sludge-wastewater mixture after aerobic treatment; The aerobic treatment reaction time is 120-200 min, and the temperature is 19-21℃; S3, inoculating the activated sludge-wastewater mixture after aerobic treatment into an aerobic environment for aerobic starvation treatment, and obtaining an activated sludge-wastewater mixture after aerobic starvation treatment; In the aerobic environment, the concentration of activated sludge is 6000-7000 mg / L; the dissolved oxygen content in the aerobic environment is greater than or equal to 6 mg / L; no nutrients are added to the aerobic environment during the aerobic starvation treatment; the aerobic starvation treatment time is 9.5-10.5 days; S4, sequentially performing anaerobic treatment and aerobic treatment on the activated sludge-wastewater mixture after aerobic starvation treatment, and obtaining wastewater after biological phosphorus removal.

2. The method for enhanced biological phosphorus removal by aerobic starvation according to claim 1, characterized in that, After the aerobic starvation treatment is completed, the abundance of fermentative PAOs in the activated sludge is 65%-78%.

3. The method for enhanced biological phosphorus removal by aerobic starvation according to claim 1 or 2, characterized in that, The anaerobic treatment step in step S4 is the same as the anaerobic treatment step in step S1, and the aerobic treatment step in step S4 is the same as the aerobic treatment step in step S1.

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