Method for improving alkalinity and recovering fungal type expanded halophilic aerobic granular sludge

Abstract

The invention discloses a method for improving alkalinity and recovering fungal type expanded halophilic aerobic granular sludge, and belongs to the technical field of sewage treatment. According to the basic principle of the method, bicarbonate is added, the alkalinity of inlet water is improved, the substrate competitive capacity of bacteria (autotrophic bacteria) and fungi can be improved by utilizing the alkalinity, the metabolic activity of filamentous fungi is inhibited, the population number of the fungi is remarkably reduced, and the bulking state of halophilic aerobic granular sludge induced by the filamentous fungi is successfully reversed; the recovery of the structure and the function of the decomposed halophilic aerobic granular sludge is realized. In this way, the sludge in which fungi grow in an outbreak mode can be recovered into a particle structure within a short time, and the good performance of sewage treatment is recovered again. Adding bicarbonate to improve alkalinity is a non-toxic and pollution-free chemical regulation mode, and the method is environment-friendly and convenient to operate. The method is remarkable in effect and low in cost.

Description

Technical Field

[0001] The present invention belongs to the field of biological sewage treatment, and specifically relates to a method for improving the alkalinity recovery of fungal bulking halophilic aerobic granular sludge. Background Art

[0002] With the acceleration of the industrialization process, the discharge of high-salt wastewater has increased sharply, and the halophilic aerobic granular sludge technology has attracted much attention due to its excellent treatment performance in high-salt environments. However, during the continuous operation of the halophilic aerobic granular sludge system, fungal bulking frequently occurs, which poses a major challenge to the stability of the system. Currently, effective recovery technologies for the disintegration of granular sludge and the deterioration of effluent quality caused by this problem are still lacking. Therefore, exploring and developing technical means that can effectively control fungal bulking and restore the stable operation of halophilic aerobic granular sludge has become a key issue that urgently needs to be solved in the fields of scientific research and practice.

[0003] Currently, the common method to inhibit the growth of filamentous microorganisms is to achieve the recovery of bulking sludge through process regulation. Research has shown that adjusting process parameters such as sludge settling time, nutrient ratio, influent load, and dissolved oxygen concentration can effectively inhibit sludge bulking. However, these technical methods are often implemented based on freshwater granular sludge, and there is limited research on recovery technical methods based on halophilic granular sludge. Moreover, these methods are time-consuming and costly. Therefore, it is urgent to develop more efficient and energy-saving recovery strategies for halophilic aerobic granular sludge to ensure the stable operation of the halophilic aerobic granular sludge system. Adding chemical agents has been proven to be an effective means to inhibit filamentous microorganisms, with the advantages of quick results and low cost. However, existing research has insufficiently studied the mechanism of action of chemical agents in regulating the excessive growth of filamentous microorganisms in high-salt environments, and there are also problems such as unclear dosing amounts.

[0004] In view of the above problems, the present invention proposes a method for improving the alkalinity recovery of fungal bulking halophilic aerobic granular sludge. By increasing the alkalinity, the ability of bacteria (autotrophic bacteria) to compete for substrates with fungi is enhanced, so as to achieve the purpose of inhibiting the proliferation of filamentous fungi and reducing the fungal population, thereby restoring the compact and stable structure of halophilic aerobic granular sludge. Summary of the Invention

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

[0006] The present invention provides a method for improving the alkalinity recovery of fungal bulking halophilic aerobic granular sludge, which is characterized in that: by adding bicarbonate to the halophilic aerobic granular sludge with fungal bulking, the influent alkalinity is increased. Under the action of high alkalinity, the negative effects of alkalinity on the spore germination and activity of fungi are utilized to inhibit the growth and proliferation of fungi, and then the halophilic aerobic granular sludge with fungal bulking is restored. The implemented device is asFigure 1 As shown in the figure, it includes: a medicine - dispensing water tank (1), a lift pump (2), and a flowmeter (3). Among them, the inlet end of the lift pump (2) is connected to the medicine - dispensing water tank (1), and the outlet end is connected to the aeration tank through a pipeline provided with a flowmeter (3).

[0007] Based on the above - mentioned device, the steps to improve the alkalinity - restored fungal - bulking halophilic aerobic granular sludge include:

[0008] Step 1: Measure the original alkalinity concentration in the influent water as C0 mg CaCO3 / L.

[0009] Step 2: Configure a concentrated mother liquor with an alkalinity concentration of C1 mg CaCO3 / L using bicarbonate and store it in the water tank (1).

[0010] Step 3: Turn on the lift pump (2), control the flowmeter (3), and introduce the mother liquor in the medicine - dispensing water tank (1) into the inlet of the aeration tank of the halophilic aerobic granular sludge with fungal bulking. Control the flow rate V of the lift pump within the range of where V is the flow rate of the lift pump, m 3 / h; Q is the designed water volume of the aeration tank, m 3 ; HRT is the hydraulic retention time of the aeration tank, h; continuously operate for 30 - 40 days.

[0011] Step 4: Repeat Step 3, keep the mother - liquor alkalinity concentration C1 unchanged, increase the lift - pump flow rate V to 1.2 - 1.5 times the original value and continuously operate for 30 - 40 days until there are no visible hyphae on the sludge surface under naked - eye or microscope observation (4× - 10×), and the sludge volume index (SVI) ≤ 50 mL / g.

[0012] Step 5: Stop introducing bicarbonate.

[0013] The technical principle of the present invention is that the change in alkalinity can affect the metabolic level and cell activity of microorganisms, causing different biological effects on bacteria and fungi. For bacteria, a high alkalinity concentration can provide an inorganic carbon source for autotrophic bacteria, enhance the ability of bacteria (autotrophic bacteria) to compete for substrate resources with filamentous fungi, increase the population number of autotrophic bacteria, and promote the secretion of extracellular polymers, improving the aggregation ability of sludge. For fungi, high alkalinity can inhibit the utilization of nutrients by fungi, reduce the activity of fungi, and can damage the cell membrane of fungi, having a fungicidal effect, thereby inhibiting the proliferation of filamentous fungi and reducing the number of filamentous fungi. This method can restore the stable structure of fungal - type bulking halophilic aerobic granular sludge, which provides valuable guidance for the continuous and stable operation of halophilic aerobic granular sludge technology in practice.

[0014] The beneficial effects of the present invention are as follows:

[0015] (1) The control parameters are simple and clear, and the alkalinity index is easy to monitor and regulate.

[0016] (2) Under the action of high alkalinity, the growth of fungi can be inhibited, and the compact and stable structure of the fungal bulking halophilic aerobic granular sludge can be restored.

[0017] (3) The bicarbonate added in the present invention has high safety, no residual risk, and will not cause ecological risks or environmental pollution to the sludge treatment system. This method is simple, safe, efficient, stable and reliable, and is an effective method for restoring fungal bulking halophilic aerobic granular sludge that can be widely promoted. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the device used in the present invention: chemical dosing water tank (1), lift pump (2), flow meter (3).

[0019] Figure 2 Schematic diagram of the principle of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] The present invention will be further described in detail below in conjunction with the embodiments. The following embodiments are implemented on the premise of the technical solution of the present invention, and the detailed implementation manners and specific operation processes are given, but the present invention is not limited to the following embodiments.

[0021] Example 1: Restoring fungal bulking halophilic aerobic granular sludge with an alkalinity concentration of 3000 mg CaCO3 / L

[0022] Step 1: Measure the original alkalinity concentration in the influent water to be 400 mg CaCO3 / L.

[0023] Step 2: Use sodium bicarbonate to prepare a concentrated mother liquor with an alkalinity concentration of 30000 mg CaCO3 / L and store it in the chemical dosing water tank (1);

[0024] Step 3: Turn on the lift pump (2), control the flow meter (3), introduce the mother liquor in the chemical dosing water tank (1) into the inlet of the aeration tank of the halophilic aerobic granular sludge with fungal bulking, adjust the flow rate of the lift pump, so that the alkalinity concentration in the aeration tank is 3000 mg CaCO3 / L, and continuously operate for 30 - 40 days;

[0025] Step 4: Observe the sludge surface until there are no visible hyphae on the sludge surface under naked eye or microscope observation (4× - 10×), and the sludge volume index (SVI) ≤ 50 mL / g.

[0026] Step 5: Stop introducing sodium bicarbonate.

[0027] After continuous operation for 40 days at an alkalinity of 3000 mg CaCO3 / L, the activity of bacteria increased significantly, the number of fungi decreased significantly, and the ratio of the number of fungi to bacteria was lower than 2×10 -6 . The restored halophilic aerobic granular sludge had a compact and dense structure, with an average particle size reaching 762.9±1.95 μm, and the system operated stably.

Claims

1. A method for restoring filamentous fungal bulking halophilic aerobic granular sludge by increasing alkalinity, characterized in that, The devices used include: a chemical dosing water tank (1), a lift pump (2), and a flowmeter (3); among them, the inlet end of the lift pump (2) is connected to the chemical dosing water tank (1), and the outlet end is connected to the aeration tank through a pipeline provided with a flowmeter (3); The steps for implementing with the above devices are as follows: Step 1: Measure the original alkalinity concentration in the influent as C0 mg CaCO3 / L; Step 2: Configure a concentrated mother liquor with an alkalinity concentration of C1 mg CaCO3 / L using bicarbonate and store it in the water tank (1); Step 3: Turn on the lift pump (2), control the flowmeter (3), and introduce the mother liquor in the chemical dosing water tank (1) to the inlet of the aeration tank of the halophilic aerobic granular sludge with fungal expansion. Control the flow rate V of the lift pump within the range of where V is the flow rate of the lift pump, m 3 / h; Q is the designed water volume of the aeration tank, m 3 ; HRT is the hydraulic retention time of the aeration tank, h; Operate continuously for 30 to 40 days; Step 4: Repeat Step 3, keep the mother liquor alkalinity concentration C1 unchanged, increase the lift pump flow rate V to 1.2 - 1.5 times the original value and run continuously for 30 - 40 days until no visible hyphae are on the sludge surface and the sludge volume index SVI ≤ 50 mL / g; Step 5: Stop introducing bicarbonate.

2. A method for restoring filamentous fungal bulking halophilic aerobic granular sludge by increasing alkalinity according to claim 1, characterized in that: The bicarbonate described in Step 1 includes sodium bicarbonate or potassium bicarbonate.

3. A method for restoring filamentous fungal bulking halophilic aerobic granular sludge by increasing alkalinity according to claim 1, characterized in that: The mother liquor concentration described in step 3 should satisfy:

4. A method for restoring filamentous fungal bulking halophilic aerobic granular sludge by increasing alkalinity according to claim 1, characterized in that: The flow rate of the lift pump described in Step 3 and Step 4 should satisfy That is, the restricted flow rate V should not exceed 10% of the influent flow rate of the aeration tank.

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