An enhanced cold-frozen anaerobic ammonium oxidation sludge remodeling device and its operation method

Abstract

This invention proposes an enhanced refolding device and operating method for refrigerated anaerobic ammonia oxidation sludge. The device includes a sampling port straight-tube syringe (1), an inlet straight-tube syringe (2), a three-way valve (3), a magnetic stirrer (4), an anode (8), a cathode (9), a changeover switch (10), an air bag (11), a reaction vessel, a power supply assembly, an air inlet (a) and an air outlet (b) of a hose syringe. The power supply assembly includes a voltage data acquisition system (5), a DC regulated power supply (6), and a resistor (7). In this invention, an additional volume of activated sludge is added as an enhanced refolding factor during the mainstream wastewater denitrification process. This accelerates the recovery of the activity of refrigerated anaerobic ammonia oxidizing bacteria, improves the overall denitrification efficiency of the system, and promotes the operation of the mainstream anaerobic ammonia oxidation system under two different electron acceptor conditions: nitrite and electrodes.

Description

Technical Field

[0001] This invention relates to an enhanced cold-cooled anaerobic ammonium oxidation sludge remodeling device and its operation method, belonging to the field of sludge treatment. Background Technology

[0002] Anaerobic ammonia oxidation (AAO), as an emerging nitrogen removal process, offers significant advantages over traditional biological nitrogen removal methods. It requires less organic carbon source, aeration, and sludge, exhibiting a high degree of energy efficiency and significant potential for bioenergy recovery. Due to the long generation cycle of AAO bacteria and their strict environmental requirements, refrigeration is often used to preserve them and minimize activity loss. Currently, the main challenge in starting up mainstream wastewater nitrogen removal processes with refrigerated AAO sludge is the slow recovery rate of bacterial activity. Therefore, accelerating the recovery of bacterial activity in refrigerated AAO sludge and improving the overall nitrogen removal efficiency of the system is crucial for the practical application of AAO nitrogen removal technology.

[0003] Compared to industrial and sidestream wastewater, mainstream wastewater not only has a larger discharge volume, but also a much higher ammonia nitrogen emission from domestic sources compared to industrial sources. Therefore, applying anammox technology to mainstream wastewater denitrification will generate significant environmental and economic benefits. Compared to commonly used enhanced chemical agents, activated sludge with a complex microbial community can form a positive interaction with the anammox sludge microbial community, improving the denitrification efficiency of the anammox system and demonstrating a significant advantage in "treating waste with waste." Based on this, activated sludge can be used to enhance the performance of a refrigerated anammox sludge system, and a method to accelerate the recovery of the activity of the refrigerated anammox sludge microbial community can be invented. Since a single electron acceptor may lead to random experimental results, the refrigerated sludge anammox system is configured with nitrite and conductive carbon-based felt as two different electron acceptors to conduct a stable sequencing batch refrigerated anammox denitrification reaction. Summary of the Invention

[0004] To address the problem of low denitrification efficiency when anammox sludge is inoculated into the mainstream wastewater denitrification process, this invention designs and proposes an enhanced anammox sludge regeneration device and its operation method.

[0005] The technical solution adopted by the present invention to solve the above problems is as follows: The present invention proposes an enhanced cold-stored anaerobic ammonia oxidation sludge remodeling device, comprising:

[0006] Sampling port straight-tube syringe (1), inlet straight-tube syringe (2), three-way valve (3), magnetic stirrer (4), anode (8), cathode (9), changeover switch (10), gas bag (11), reaction vessel, power supply assembly, hose syringe inlet (a) and hose syringe outlet (b);

[0007] The reaction vessel is set on the magnetic base of the magnetic stirrer (4). The rotor that cooperates with the magnetic stirrer (4) is placed at the bottom of the reaction vessel. The sampling port straight syringe (1) and the injection port straight syringe (2) are connected to the container opening of the reaction vessel through the three-way valve (3). The anode (8) and the cathode (9) are set inside the reaction vessel. The anode (8) and the cathode (9) are connected to the power supply assembly respectively. The reaction vessel is connected to the air bag (11) through the hose syringe air inlet (a) and the hose syringe air outlet (b).

[0008] Optionally, the power supply components include a voltage data acquisition system (5), a DC regulated power supply (6), and a resistor (7). The anode (8), cathode (9), resistor (7), DC regulated power supply (6), and changeover switch (10) are connected in series to form an external circuit. The voltage data acquisition system (5) is connected in parallel across the resistor (7).

[0009] Optionally, the changeover switch (10) is used to control the open and closed circuits of the external circuit. When the external circuit is open, the anaerobic ammonia oxidation system (C) with nitrite as the electron acceptor is operated, and when the external circuit is closed, the electro-anaerobic ammonia oxidation system (E) with conductive carbon-based material carbon felt as the electron acceptor is operated.

[0010] A method for operating an enhanced cold-stored anaerobic ammonia oxidation sludge remodeling device includes:

[0011] Step 1: Activated sludge with a sludge concentration of 3 g / L and refrigerated anaerobic ammonia oxidation sludge with a concentration of 9 g / L are introduced into the reaction vessel through the straight-tube syringe (2) via the left injection port of the three-way valve (3) at a pumping speed of 10 mL / min.

[0012] Step 2: Control the opening and closing of the external circuit through the changeover switch (10). When the external circuit is open, add NaNO2 to the anaerobic ammonia oxidation system (C) according to the theoretical ratio of anaerobic ammonia oxidation to supply NO2. – Electron acceptor, in a closed-loop state, the electro-anaerobic ammonia oxidation system (E) uses the electrode as an electron acceptor to promote the formation of anaerobic ammonia oxidation biofilm on the surface of the main anode (8) and cathode (9) of the sequencing batch reactor with two different electron acceptors;

[0013] Step 3: The wastewater is transported to the reaction vessel through the straight-tube syringe (2) and the left side of the three-way valve (3). The wastewater is homogenized by the magnetic stirrer (4) and the rotor at a speed of 200-300 rpm and then fully mixed and reacted. Refrigerated anaerobic ammonia oxidation sludge is selected as inoculum and activated sludge is used as a sludge refolding enhancer.

[0014] Step 4: Disconnect the connection between the straight-tube syringe (2) and the reaction container. After disconnection, the syringe is in a closed state. The wastewater is subjected to nitrogen aeration deoxygenation pretreatment through the three-way valve (3) and the sampling port. During the denitrification reaction of homogenized wastewater, nitrogen is discharged from the inlet (a) of the flexible syringe to the outlet (b) of the flexible syringe and collected by the nitrogen bag. After the reaction is completed, the water sample is taken out through the straight-tube syringe (1) at 20 mL / min to complete the entire deoxygenation chain reaction of the enhanced refolded refrigerated anaerobic ammonia oxidation sludge.

[0015] Optionally, in step 1, the volume ratio of activated sludge and refrigerated anaerobic ammonia oxidation sludge is 1:1, and both are prepared using 25 mL / L culture medium.

[0016] Optionally, wastewater environmental conditions may be controlled during the operation of the denitrification reaction system in step 3.

[0017] Wastewater environmental conditions control includes a pH value of 7.5-8.5, a temperature of 25-30℃, an ammonia nitrogen concentration range of 0.315-0.631 mg / L, and NH4+. + -N and NO2 - The mass concentration ratio of -N is 1:(1-1.32).

[0018] Optionally, in step 3, the output voltage of the external DC regulated power supply of the electro-anaerobic ammonia oxidation system (E) in the closed-loop state is set to 0.6V, and the voltage data acquisition system (5) is used to record the voltage across the resistor (7) during operation.

[0019] The beneficial effects of this invention are:

[0020] In this invention, during the startup of a mainstream wastewater denitrification process using refrigerated anammox sludge, an additional volume of activated sludge is added as a refolding enhancer to accelerate the recovery of refrigerated anammox bacteria activity, thereby improving the overall denitrification efficiency of the system. This method promotes the startup of the mainstream anammox process under both traditional nitrite and electrode electron acceptor conditions. It provides a novel method for accelerating the recovery of anammox bacteria activity after low-temperature treatment. Attached Figure Description

[0021] Figure 1 This is a structural diagram of an enhanced cold-stored anaerobic ammonium oxidation sludge remodeling device provided in an embodiment of the present invention;

[0022] Figure 2 A diagram illustrating the ammonia nitrogen conversion effect provided in an embodiment of the present invention;

[0023] Figure 3 A flowchart illustrating the operation method of an enhanced cold-stored anammox sludge remodeling device provided in an embodiment of the present invention;

[0024] In the diagram, 1-Sampling port straight syringe, 2-Inlet straight syringe, 3-Three-way valve, 4-Magnetic stirrer, 5-Voltage data acquisition system, 6-DC regulated power supply, 7-Resistor, 8-Anode, 9-Cathode, 10-Changeover switch, 11-Air bag, a-Hose syringe air inlet, b-Hose syringe air outlet.

[0025] Example

[0026] Example 1

[0027] Combination Figure 1-3 This embodiment will be described as follows: Figure 1 and Figure 3 As shown, a sequencing batch reactor (SBR) refrigerated anaerobic ammonia oxidation denitrification system (C) with added activated sludge (Ms) and without added activated sludge (An) is used for wastewater denitrification. The reaction vessel is a sequencing batch reactor, and the specific operating steps are as follows:

[0028] First, a sequencing batch reactor (SBR) refrigerated anaerobic ammonia oxidation (ANOVA) denitrification system with activated sludge (Ms_C) and a SBR refrigerated ANOVA denitrification system without activated sludge (An_C) were constructed. The total reactor volume was 250 mL, of which the cylindrical reaction zone had a volume of 200 mL and the top conical gas phase escaping zone had a volume of 50 mL. The inner diameter of the cylindrical reaction zone was 6.26 cm and the total height was 6.5 cm. Two completely opposite carbon fiber felts were set as electrodes in the reaction zone and connected to an external DC regulated power supply via wires. The carbon fiber felt connected to the positive terminal of the power supply was the anode carbon fiber felt, and the carbon fiber felt connected to the negative terminal of the power supply was the cathode carbon fiber felt. The anode carbon fiber felt (8) and the cathode carbon fiber felt (9) were arranged on both sides of the axis of the reaction zone, and the distance between the top of the anode carbon fiber felt (8) and the bottom of the cathode carbon fiber felt (9) was 2 cm to avoid short circuit between the anode and cathode carbon fibers. The carbon fiber felt electrode is composed of conductive carbon fiber felt and a titanium wire skeleton. The conductive carbon fiber is used for microbial attachment. The carbon fiber felt is 3cm long, 2.5cm wide, and 0.2cm thick. The system's matching straight-tube direct injection sampler and direct-injection sampler are made of high-molecular-weight polypropylene and have a cylindrical structure. Their volume can be flexibly adjusted according to the actual hydraulic retention time and water exchange ratio. The reactor is equipped with a nitrogen bag connected to a flexible syringe, which not only collects the generated gas but also balances the gas pressure.

[0029] Both the sequencing batch anaerobic ammonia oxidation denitrification (SBO) system with activated sludge (Ms_C) and the SBO system without activated sludge (An_C) use synthetic wastewater as influent during operation. The artificially synthesized wastewater consists of a nitrogen-rich culture medium and a trace element solution. The nitrogen-rich culture medium contains KHCO3 (0.428 g / L), NaH2PO4 (0.060 g / L), CaCl2 (0.055 g / L), NH4Cl (0.631 g / L), and NaNO2 (1.074 g / L). The trace element solution contains H3BO4 (0.014 g / L), CuSO4 (0.016 g / L), MnCl2 (0.051 g / L), ZnSO4 (0.022 g / L), CoCl2 (0.016 g / L), NiCl2 (0.190 g / L), Na2SeO4 (0.210 g / L), NaMoO4 (0.220 g / L), Na2WO4 (0.050 g / L), FeSO4 (5 g / L), and EDTA (5 g / L). The prepared nitrogen culture medium was added to the trace element solution at a ratio of 5 mL / L. After stirring evenly, the pH was adjusted to 7.5~8.5 and added to the reactor. Then, it was aerated with high-purity nitrogen for 15 min to remove dissolved oxygen from the synthetic wastewater.

[0030] like Figure 2 As shown, the inoculum for Ms_C and An_C during startup was 9 g / L of anaerobic ammonia oxidation granular sludge, with an inoculum volume of 10 mL. For Ms_C, additional activated sludge was added as a refolding enhancer. Initially, an anaerobic ammonia oxidation biofilm formed on the carbon fiber felt surface. During this process, the influent ammonia nitrogen and nitrite nitrogen concentrations were 0.631 g / L and 1.074 g / L, respectively, and the external circuit of the sequencing batch reactor (C) was kept disconnected. Compared to the initial ammonia nitrogen removal rates of 14% and 8% for Ms_C and An_C, respectively, after 15 days of reactor operation, the ammonia nitrogen removal rates for Ms_C and An_C reached 29% and 11%, respectively. Subsequently, the ammonia nitrogen removal rate of Ms_C remained above that of An_C, and the gap gradually widened. Simultaneously, a red anaerobic ammonia oxidation biofilm was observed forming on the carbon fiber felt surface during operation. The reaction system inoculated only with refrigerated anammox sludge (An_C) showed a higher ammonia nitrogen removal rate recovery speed than the refrigerated anammox sludge system (Ms_C) with activated sludge added, effectively demonstrating that adding activated sludge can enhance the refolding of refrigerated anammox sludge.

[0031] Example 2

[0032] Combination Figure 1-3 This embodiment will be described as follows: Figure 1 and Figure 3As shown, a sequencing batch electro-refrigerated anaerobic ammonia oxidation denitrification system (E) with added activated sludge (As) and without added activated sludge (An) is used for wastewater denitrification. The reaction vessel is a sequencing batch reactor, and the specific operating steps are as follows:

[0033] First, an electric-refrigerated anaerobic ammonia oxidation denitrification system was constructed. Except for the main reactor, where the external circuit remained closed, all other aspects were consistent with Example 1.

[0034] The sequencing batch electro-anaerobic ammonia oxidation denitrification system (E) is identical to the sequencing batch anaerobic ammonia oxidation denitrification system (C) except that the synthetic wastewater formulation does not contain NaNO2 (1.074 g / L).

[0035] like Figure 2 As shown, the inoculum used in the start-up processes of Ms_E and An_E was refrigerated anammox sludge, with an inoculum volume of 10 mL. Activated sludge was additionally added to the former as a refolding enhancer. In the initial stage of start-up, an electro-anammox biofilm first formed on the surface of the carbon fiber felt. During this process, the influent ammonia nitrogen and nitrite nitrogen concentrations were 165 mg / L and 0 mg / L, respectively, and the external circuit remained closed. Compared to the initial start-up of both Ms_E and An_E, where the ammonia nitrogen concentration increased rather than decreased, after 27 days of reactor operation, the ammonia nitrogen removal rate of Ms_E increased to 15%, compared to the still negative value of An_E. Simultaneously, a red anammox biofilm was observed forming on the surface of the carbon fiber felt. The higher ammonia nitrogen removal rate recovery rate of the sequencing batch electro-refrigerated anammox denitrification system (Ms_E) with activated sludge effectively demonstrates that the addition of activated sludge can enhance the refolding of refrigerated anammox sludge.

[0036] In summary, the experimental results of Examples 1 and 2 show that, in both anaerobic ammonia oxidation and electro-anaerobic ammonia oxidation denitrification systems, activated sludge, compared to pure anaerobic ammonia oxidation granular sludge inoculation, acts as a refolding enhancer and has the effect of activating the activity of anaerobic ammonia oxidizing bacteria that have undergone long-term low-temperature inhibition.

[0037] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent substitutions, and improvements made to the above embodiments without departing from the scope of the present invention, based on the technical essence of the present invention and within the spirit and principles of the present invention, shall still fall within the protection scope of the present invention.

Claims

1. A method for operating an enhanced cold-cooled anaerobic ammonium oxidation sludge remodeling device, characterized in that, The device used in the enhanced cold-resistant anaerobic ammonia oxidation sludge remodeling device operation method includes: Sampling port straight-tube syringe (1), inlet straight-tube syringe (2), three-way valve (3), magnetic stirrer (4), anode (8), cathode (9), changeover switch (10), gas bag (11), reaction vessel, power supply assembly, hose syringe inlet (a) and hose syringe outlet (b); The power supply assembly includes a voltage data acquisition system (5), a DC regulated power supply (6), and a resistor (7). The anode (8), cathode (9), resistor (7), DC regulated power supply (6), and changeover switch (10) are connected in series to form an external circuit. The voltage data acquisition system (5) is connected in parallel on both sides of the resistor (7). The switching switch (10) is used to control the opening and closing of the external circuit. When the external circuit is open, the anaerobic ammonia oxidation system (C) with nitrite as the electron acceptor is operated. When the external circuit is closed, the electro-anaerobic ammonia oxidation system (E) with conductive carbon-based material carbon felt as the electron acceptor is operated. The reaction container is set on the magnetic base of the magnetic stirrer (4). The rotor that cooperates with the magnetic stirrer (4) is placed at the bottom of the reaction container. The sampling port straight-tube syringe (1) and the injection port straight-tube syringe (2) are connected to the container opening of the reaction container through a three-way valve (3). The anode (8) and the cathode (9) are set in the reaction container. The anode (8) and the cathode (9) are respectively connected to the power supply assembly. The reaction container is connected to the air bag (11) through the hose syringe air inlet (a) and the hose syringe air outlet (b). The operation method of the enhanced cold-resistant anaerobic ammonia oxidation sludge remodeling device includes: Step 1: Activated sludge with a sludge concentration of 3 g / L and refrigerated anaerobic ammonia oxidation sludge with a concentration of 9 g / L are introduced into the reaction vessel through the straight-tube syringe (2) via the left injection port of the three-way valve (3) at a pumping speed of 10 mL / min. Step 2: Control the opening and closing of the external circuit through the changeover switch (10). When the external circuit is open, add NaNO2 to the anaerobic ammonia oxidation system (C) according to the theoretical ratio of anaerobic ammonia oxidation. Electron acceptor, in a closed-loop state, the electro-anaerobic ammonia oxidation system (E) uses the electrode as an electron acceptor to promote the formation of anaerobic ammonia oxidation biofilm on the surface of the main anode (8) and cathode (9) of the sequencing batch reactor with two different electron acceptors; Step 3: The wastewater is transported to the reaction vessel through the straight-tube syringe (2) and the left side of the three-way valve (3). The wastewater is homogenized by the magnetic stirrer (4) and the rotor at a speed of 200-300 rpm and then fully mixed and reacted. Refrigerated anaerobic ammonia oxidation sludge is selected as inoculum and activated sludge is used as a sludge refolding enhancer. Step 4: Disconnect the connection between the straight-tube syringe (2) and the reaction container. After disconnection, the syringe is in a closed state. The wastewater is subjected to nitrogen aeration deoxygenation pretreatment through the three-way valve (3) and the sampling port. During the denitrification reaction of homogenized wastewater, nitrogen is discharged from the inlet (a) of the flexible syringe to the outlet (b) of the flexible syringe and collected by the nitrogen bag. After the reaction is completed, the water sample is taken out through the straight-tube syringe (1) at 20 mL / min to complete the entire deoxygenation chain reaction of the enhanced refolded refrigerated anaerobic ammonia oxidation sludge.

2. The method for operating an enhanced cold-resistant anaerobic ammonia oxidation sludge remodeling device according to claim 1, characterized in that, In step 1, the volume ratio of activated sludge and refrigerated anaerobic ammonia oxidation sludge was 1:1, and both were prepared using 25 mL / L culture medium.

3. The method for operating an enhanced cold-resistant anaerobic ammonia oxidation sludge remodeling device according to claim 1, characterized in that, In step 3, wastewater environmental conditions are controlled during the operation of the denitrification reaction system. The wastewater environmental conditions control includes a pH value of 7.5-8.5, a temperature of 25-30℃, an ammonia nitrogen concentration range of 0.315-0.631 mg / L, and NH4+ concentration of... + -N and The mass concentration ratio of -N is 1:(1-1.32).

4. The method for operating an enhanced cold-resistant anaerobic ammonia oxidation sludge remodeling device according to claim 1, characterized in that, In step 2, the output voltage of the external DC regulated power supply of the electro-anaerobic ammonia oxidation system (E) in the closed-loop state is set to 0.6V, and the voltage data acquisition system (5) is used to record the voltage across the resistor (7) during operation.

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