Method for recovering fungus expanded halophilic aerobic granular sludge by using iron ions

Abstract

The invention discloses a method for recovering fungus expanded halophilic aerobic granular sludge by using iron ions, and belongs to the field of biological sewage treatment. The principle of the method is as follows: by adding iron ions and utilizing different biological effects caused by the iron ions on bacteria and fungi, the proliferation of the bacteria is promoted, and the proliferation of the fungi is inhibited, so that the number of the fungi is reduced, and the recovery of the compact and stable structure of the fungus expansion halophilic aerobic granular sludge is realized. According to the invention, the halophilic aerobic granular sludge on which fungi overgrow can recover compact and compact granules in a short time, so that stable operation of the system and rapid treatment of high-salinity wastewater are ensured. The iron ion concentration utilized by the method does not cause ecological risk or environmental pollution to a sludge treatment system, and the method is low in cost, simple to operate, safe, efficient, stable and reliable.

Description

Technical Field

[0001] The present invention belongs to the field of biological sewage treatment, and specifically relates to a method for restoring fungal swelling halophilic aerobic granular sludge by utilizing iron ions. Background Art

[0002] With the development of industry, the amount of high-salinity wastewater is increasing. Since freshwater microorganisms cannot survive under high-salinity conditions, halophilic aerobic granular sludge cultivated with halophilic microorganisms has shown excellent pollutant degradation ability in high-salinity wastewater treatment. In the formation process of halophilic aerobic granular sludge, fungi can serve as particle cores to increase the bacterial colonization area. However, changes in environmental conditions and operating parameters can easily cause fungal expansion and disintegration of granular sludge, resulting in large-scale sludge loss and deterioration of effluent, which limits the widespread application of halophilic aerobic granular sludge.

[0003] Researchers have proposed several solutions for how to restore granular sludge. Patent CN201810013867.9 effectively controls sludge expansion and forms granular sludge with a smooth and round appearance by changing the operating conditions of the reactor, increasing the aeration intensity and gradually shortening the sedimentation time. Patent CN201210158479.2 increases the chemical oxygen demand (COD) of the influent to 1000-1500 mg / L, so that the flocculent bacteria that are conducive to granular stability gain a competitive advantage over the filamentous bacteria, and then uses the high hydraulic shear force provided by the high aeration volume (4-7L / min) to make the filamentous bacteria fall off the surface of the granular sludge and discharge it out of the system, restoring the compact structure of the granular sludge. Patent CN201910301631.X promotes microorganisms to secrete more extracellular polymers by adding quorum sensing signal molecules, increases the density and hydrophobicity of granular sludge, and restores the structure of the disintegrated granular sludge to its integrity. However, these technical methods are all implemented based on freshwater granular sludge, and there is limited research on restoration technical methods based on halophilic granular sludge. Patent CN202211223203.8 uses the different biomagnetic effects of magnetic fields on bacteria and fungi. By applying an exogenous magnetic field, the proliferation of filamentous fungi is effectively inhibited, thereby achieving the recovery of fungal-expanded halophilic granular sludge. However, due to high cost, high energy consumption and space limitations, the application scenarios of exogenous magnetic fields are relatively limited. It is urgent to develop more efficient and energy-saving halophilic aerobic granular sludge recovery strategies to ensure the stable operation of the halophilic aerobic granular sludge system.

[0004] In view of the above problems, the present invention proposes a method for restoring fungal swelling of halophilic aerobic granular sludge using iron ions. By adding iron ions, the proliferation of fungi is effectively inhibited, the number of fungi is reduced, and the compact and stable structure of the halophilic aerobic granular sludge is restored. Summary of the invention

[0005] The purpose of the present invention is to restore the fungus-bloated halophilic aerobic granular sludge and ensure its long-term stable operation in practical applications.

[0006] The present invention proposes a method for restoring fungus-swelling halophilic aerobic granular sludge by using iron ions, which is characterized by: adding iron ions to the halophilic aerobic granular sludge with fungus swelling, utilizing the inhibitory effect of iron ions on fungal proliferation, reducing the number of fungi, and thus restoring the compact and stable structure of the halophilic aerobic granular sludge. Figure 1 As shown, it comprises: (1) a water tank, and (2) a lifting pump. The treatment process of the device is to allow the iron ion concentrated mother liquor in the water tank (1) to enter the inlet of the sewage treatment aeration tank through the lifting pump (2).

[0007] Based on the above device, the steps of restoring the fungal swelling halophilic aerobic granular sludge with iron ions include:

[0008] Step 1: Use iron salt to prepare a concentrated mother solution with an iron ion concentration of 50 to 100 g / L, and store it in a water tank (1).

[0009] Step 2: Turn on the lift pump (2) to introduce the mother liquid in the water tank (1) into the inlet of the halophilic aerobic granular sludge aeration tank where fungal expansion occurs. The calculation formula for the lift pump flow rate is: Where C1 is the iron ion concentration in the aeration tank, 5-10 mg / L, C0 is the mother liquor concentration, Q is the designed water volume of the aeration tank, and HRT is the hydraulic retention time of the aeration tank.

[0010] Step 3: Run continuously for 20 to 30 days and observe the sludge surface until there is no obvious mycelium on the sludge surface. The sludge settling performance is good, and the fungus-swollen halophilic aerobic granular sludge restores a compact structure.

[0011] Step 4: Stop introducing iron ions.

[0012] Step 5: If there are still hyphae on the sludge surface, repeat steps 1 and 2 for 20 to 30 days until there are no obvious hyphae on the sludge surface.

[0013] The iron salt described in step 1 includes ferric chloride, ferric sulfate and ferric nitrate.

[0014] Technical principle of the present invention:

[0015] The present invention utilizes the difference in the effect of iron ions on the proliferation of fungi and bacteria to restore the compact and stable structure of halophilic aerobic granular sludge. Figure 2. Iron ions can affect the metabolic level and cell activity of microorganisms, causing different biological effects on bacteria and fungi. For bacteria, iron ions at a concentration of 5 to 10 mg / L can act as an enzyme cofactor to promote the synthesis of bacterial iron-sulfur proteins and hemoglobin. For fungi, iron ions at a concentration of 5 to 10 mg / L will wrap and cover the fungal hyphae, inhibit the fungi from utilizing nutrients, and have a toxic effect on the fungal hyphae. Therefore, under the action of the same concentration of iron ions, the proliferation of bacteria is promoted, while the proliferation of fungi is inhibited, thereby reducing the number of fungi. This method can restore the compact and stable structure of fungal-expanded halophilic aerobic granular sludge.

[0016] Beneficial effects of the present invention:

[0017] Through the above method, under the action of iron ions, the growth of fungi can be inhibited and the compact and stable structure of fungal-expanded halophilic aerobic granular sludge can be restored.

[0018] Iron salt is a commonly used flocculant in sewage treatment plants. Iron ions at a concentration of 5 to 10 mg / L will not cause ecological risks or environmental pollution to the sludge treatment system. This method is low-cost, simple to operate, safe and efficient, stable and reliable. It is an effective method for restoring fungal-expanded halophilic aerobic granular sludge that can be widely promoted. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the device structure used in the present invention: (1) water tank, (2) lifting pump.

[0020] Figure 2 It is the effect diagram of the present invention. DETAILED DESCRIPTION

[0021] The present invention will be further described in detail in combination with embodiments with reference to the accompanying drawings, but the present invention is not limited to the following embodiments.

[0022] The effects of Examples 1-6 are very similar and can be used Figure 2 express.

[0023] Example 1: Restoration of fungal swelling in halophilic aerobic granular sludge using 5 mg / L iron ions

[0024] Step 1: Use ferric chloride to prepare a concentrated mother solution with an iron ion concentration of 50 g / L, and store it in a water tank (1).

[0025] Step 2: Turn on the lifting pump (2) to introduce the mother liquid in the water tank (1) into the inlet of the halophilic aerobic granular sludge aeration tank where fungal swelling occurs, so that the iron ion concentration in the aeration tank is maintained at 5 mg / L.

[0026] Step 3: Run continuously for 20 days and observe the sludge surface until there is no obvious mycelium on the sludge surface. The sludge settling performance is good, and the fungus-swollen halophilic aerobic granular sludge restores a compact structure.

[0027] Step 4: Stop introducing iron ions.

[0028] After the introduction of 5 mg / L iron ions for 20 consecutive days, the number of bacteria increased significantly and the number of fungi decreased significantly. The structure of the recovered halophilic aerobic granular sludge was compact and the system operated stably.

[0029] Example 2: Restoration of fungal swelling in halophilic aerobic granular sludge using 6 mg / L iron ions

[0030] Step 1: Use ferric chloride to prepare a concentrated mother solution with an iron ion concentration of 60 g / L, and store it in a water tank (1).

[0031] Step 2: Turn on the lifting pump (2) to introduce the mother liquid in the water tank (1) into the inlet of the halophilic aerobic granular sludge aeration tank where fungal swelling occurs, so that the iron ion concentration in the aeration tank is maintained at 6 mg / L.

[0032] Step 3: Run continuously for 20 days and observe the sludge surface until there is no obvious mycelium on the sludge surface. The sludge settling performance is good, and the fungus-swollen halophilic aerobic granular sludge restores a compact structure.

[0033] Step 4: Stop introducing iron ions.

[0034] After the introduction of 6 mg / L iron ions for 20 consecutive days, the number of bacteria increased significantly and the number of fungi decreased significantly. The structure of the recovered halophilic aerobic granular sludge was compact and the system operated stably.

[0035] Example 3: Restoration of fungal swelling in halophilic aerobic granular sludge using 7 mg / L iron ions

[0036] Step 1: Use ferric chloride to prepare a concentrated mother solution with an iron ion concentration of 70 g / L, and store it in a water tank (1).

[0037] Step 2: Turn on the lifting pump (2) to introduce the mother liquid in the water tank (1) into the inlet of the halophilic aerobic granular sludge aeration tank where fungal swelling occurs, so that the iron ion concentration in the aeration tank is maintained at 7 mg / L.

[0038] Step 3: Run continuously for 20 days and observe the sludge surface until there is no obvious mycelium on the sludge surface. The sludge settling performance is good, and the fungus-swollen halophilic aerobic granular sludge restores a compact structure.

[0039] Step 4: Stop introducing iron ions.

[0040] After the introduction of 7 mg / L iron ions for 20 consecutive days, the number of bacteria increased significantly and the number of fungi decreased significantly. The structure of the recovered halophilic aerobic granular sludge was compact and the system operated stably.

[0041] Example 4: Restoration of fungal swelling in halophilic aerobic granular sludge using 8 mg / L iron ions

[0042] Step 1: Use ferric chloride to prepare a concentrated mother solution with an iron ion concentration of 80 g / L, and store it in a water tank (1).

[0043] Step 2: Turn on the lifting pump (2) to introduce the mother liquid in the water tank (1) into the inlet of the halophilic aerobic granular sludge aeration tank where fungal swelling occurs, so that the iron ion concentration in the aeration tank is maintained at 8 mg / L.

[0044] Step 3: Run continuously for 20 days and observe the sludge surface until there is no obvious mycelium on the sludge surface. The sludge settling performance is good, and the fungus-swollen halophilic aerobic granular sludge restores a compact structure.

[0045] Step 4: Stop introducing iron ions.

[0046] After the introduction of 8 mg / L iron ions for 20 consecutive days, the number of bacteria increased significantly and the number of fungi decreased significantly. The structure of the recovered halophilic aerobic granular sludge was compact and the system operated stably.

[0047] Example 5: Restoration of fungal swelling in halophilic aerobic granular sludge using 9 mg / L iron ions

[0048] Step 1: Use ferric chloride to prepare a concentrated mother solution with an iron ion concentration of 90 g / L, and store it in a water tank (1).

[0049] Step 2: Turn on the lifting pump (2) to introduce the mother liquid in the water tank (1) into the inlet of the halophilic aerobic granular sludge aeration tank where fungal swelling occurs, so that the iron ion concentration in the aeration tank is maintained at 9 mg / L.

[0050] Step 3: Run continuously for 20 days and observe the sludge surface until there is no obvious mycelium on the sludge surface. The sludge settling performance is good, and the fungus-swollen halophilic aerobic granular sludge restores a compact structure.

[0051] Step 4: Stop introducing iron ions.

[0052] After the introduction of 9 mg / L iron ions for 20 consecutive days, the number of bacteria increased significantly and the number of fungi decreased significantly. The structure of the recovered halophilic aerobic granular sludge was compact and the system operated stably.

[0053] Example 6: Restoration of fungal swelling in halophilic aerobic granular sludge using 10 mg / L iron ions

[0054] Step 1: Use ferric chloride to prepare a concentrated mother solution with an iron ion concentration of 100 g / L, and store it in a water tank (1).

[0055] Step 2: Turn on the lifting pump (2) to introduce the mother liquid in the water tank (1) into the inlet of the halophilic aerobic granular sludge aeration tank where fungal swelling occurs, so that the iron ion concentration in the aeration tank is maintained at 10 mg / L.

[0056] Step 3: Run continuously for 20 days and observe the sludge surface until there is no obvious mycelium on the sludge surface. The sludge settling performance is good, and the fungus-swollen halophilic aerobic granular sludge restores a compact structure.

[0057] Step 4: Stop introducing iron ions.

[0058] After the introduction of 10 mg / L iron ions for 20 consecutive days, the number of bacteria increased significantly and the number of fungi decreased significantly. The structure of the recovered halophilic aerobic granular sludge was compact and the system operated stably.

Claims

1. A method for restoring fungal swelling of halophilic aerobic granular sludge using iron ions, characterized in that the steps include: Step 1: using iron salt to prepare a concentrated mother solution with an iron ion concentration of 50 to 100 g / L, and storing the concentrated mother solution in a water tank (1); Step 2: Turn on the lift pump (2) to introduce the mother liquid in the water tank (1) into the inlet of the halophilic aerobic granular sludge aeration tank where fungal expansion occurs; the calculation formula for the lift pump flow rate is: C0 is the mother liquor concentration, Q is the designed water volume of the aeration tank, and HRT is the hydraulic retention time of the aeration tank; Step 2 is used to ensure that C1, i.e., the iron ion concentration in the aeration tank, is 5-10 mg / L; Step 3: Run the sludge for 20 to 30 days and observe the sludge surface until there is no obvious mycelium visible to the naked eye; Step 4: Stop introducing iron ions.

2. The method according to claim 1, characterized in that: The iron salt described in step 1 is ferric chloride, ferric sulfate or ferric nitrate.

3. The method according to claim 1, characterized in that: Step 5: If there are still hyphae on the sludge surface, repeat steps 1 and 2 for 20 to 30 days. There will be no hyphae visible to the naked eye on the sludge surface.

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