Biofilm reactor and ammonia-nitrogen wastewater treatment method

Abstract

The invention provides a bio-membrane reactor and an ammonia-nitrogen wastewater treatment method, relates to the technical field of wastewater treatment, and utilizes the bio-membrane reactor comprising a tourmaline-based carrier to treat ammonia-nitrogen wastewater. The carrier of the bio-membrane reactor is improved to be the tourmaline-based carrier, so that the tourmaline-based carrier can be effectively promoted to release an electric field without maintaining a relatively high temperature; furthermore, the released electric field is used for adjusting the oxidation-reduction potential, reducing the association degree of water molecules, adjusting the permeability of cell membranes and increasing the activity of dehydrogenase; finally, the generation of extracellular polymeric substances is jointly promoted, so that the formation and the stability of a biological membrane are improved. In addition, the carrier of the bio-membrane reactor based on the tourmaline-based carrier has the characteristics that the preparation is simple and convenient, the service life is long, and active components are not easy to lose; and only an intermittent heating mode is needed, so that the energy consumption is relatively low. Finally, the technical effects of improving the biological treatment efficiency of the ammonia-nitrogen wastewater and reducing the operation cost are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a biofilm reactor and an ammonia nitrogen wastewater treatment method. Background Art

[0002] Anaerobic ammonium oxidation technology (Anammox) is a new type of biological denitrification technology for sewage, which can use anaerobic ammonium oxidizing bacteria (AnAOB) to convert ammonia nitrogen (NH4 + -N) and nitrite (NO2 - -N) is directly converted into nitrogen (N2), which has the advantages of saving aeration volume, no need for external organic carbon source, and reducing the amount of residual sludge. It is mainly used in the biological treatment of high-ammonia nitrogen wastewater. However, the doubling time of anaerobic ammonium oxidizing bacteria (AnAOB) is 10-14 days, which is difficult to enrich, seriously hindering the rapid start-up of the anaerobic ammonium oxidation process.

[0003] As an effective way to solve the problem of difficult enrichment of anaerobic ammonium oxidation, the moving bed biofilm reactor (MBBR) is favored for its high efficiency and operational flexibility. MBBR combines the advantages of the activated sludge method and the traditional biofilm method, and has the characteristics of resistance to shock loads, long sludge age, and less residual sludge. In recent years, domestic and foreign researchers have conducted a lot of research on the selection of carriers (polyurethane sponges, volcanic rocks, zeolites, ceramics and plastic rings, etc.) and carrier modification (surface pretreatment, biomass fixation, loading new materials, etc.), and developed a series of carriers with good hydrophilicity and electrophilicity and high biological affinity. However, there are still the following disadvantages that make it impossible to achieve large-scale engineering applications:

[0004] 1) The active components of the carrier are lost during operation; 2) A higher temperature needs to be maintained, which leads to increased energy consumption.

[0005] Therefore, there is an urgent need for a biofilm reactor that can ensure the activity of anaerobic ammonia oxidizing bacteria (AnAOB). Summary of the invention

[0006] In view of the above problems, the present invention provides a biofilm reactor and an ammonia nitrogen wastewater treatment method to solve at least one problem existing in the prior art.

[0007] To achieve the above objectives, in a first aspect, the present invention protects a biofilm reactor for treating ammonia nitrogen wastewater; the biofilm reactor includes a tourmaline-based carrier.

[0008] Further, preferably, the tourmaline-based carrier includes tourmaline powder, talcum powder, polyethylene powder and flux. The tourmaline and polyethylene materials are organically combined to form a tourmaline-based carrier, which solves the problems of complicated filler production process, harsh production conditions, and difficulty in obtaining carriers with uniform pore sizes in the prior art; among them, too small pores (<1mm) lead to poor mass transfer performance, which is not conducive to biofilm growth and even causes blockage; and larger pores easily cause biofilm to fall off and have poor stability.

[0009] Further, preferably, the mass components of the tourmaline-based carrier are 5-10 parts of tourmaline powder, 100 parts of polyethylene powder, 2-4 parts of talc powder, and 1-3 parts of flux.

[0010] Further, preferably, the tourmaline-based carrier comprises tourmaline powder, talcum powder, polyurethane powder and flux.

[0011] In a second aspect, the present invention provides a method for preparing a carrier of a biofilm reactor, the method comprising:

[0012] Mixing tourmaline powder, talcum powder, polyethylene powder and flux;

[0013] The mixed raw materials are melt-extruded through a single screw extruder to obtain a molten material;

[0014] The molten material is processed to obtain a tourmaline-based carrier.

[0015] The active component tourmaline of the carrier used in the present invention is melt-blended in high-density polyethylene, and this structure makes the tourmaline not easy to be lost, and can exert its effectiveness stably for a long time. This stability is crucial to maintaining the efficiency and effect of the long-term operation of the reactor.

[0016] Further, preferably, the method of obtaining a tourmaline-based carrier by processing the molten material comprises:

[0017] The extruded long strip of molten material is water-cooled and formed;

[0018] Cutting the cooled molten material into granular materials;

[0019] The granular material is subjected to secondary melt extrusion by a single screw extruder with a set die head, followed by traction and water cooling to form a tourmaline-based carrier.

[0020] In a third aspect, the present invention provides a method for preparing a carrier of a biofilm reactor, the method comprising:

[0021] Mixing tourmaline powder, talcum powder, polyurethane powder and flux;

[0022] The mixed raw materials are melt-extruded through a single screw extruder to obtain a molten material;

[0023] The molten material is processed to obtain a tourmaline-based carrier.

[0024] In a fourth aspect, the present invention provides a method for treating ammonia nitrogen wastewater.

[0025] Ammonia nitrogen wastewater treatment is carried out using the biofilm reactor comprising a tourmaline-based carrier as described in claim 1.

[0026] Furthermore, preferably, the filling ratio of the tourmaline-based carrier is 25% to 40%.

[0027] Further, preferably, the biofilm reactor treats wastewater under variable temperature conditions in a light-shielded and closed environment; wherein the variable temperature condition is to control the temperature to vary between room temperature and 37°C. The variable temperature is achieved by adjusting the opening and closing time of the water bath. The present invention controls the system temperature to vary between room temperature and 37 degrees Celsius, and utilizes temperature changes to promote the release of the electric field by the tourmaline-based carrier. This temperature change helps to regulate the redox potential, reduce the degree of association of water molecules, and then regulate the permeability of the cell membrane, increase the activity of dehydrogenases, and promote the formation of extracellular polymers. In addition, the temperature change is achieved by controlling the intermittent operation of the water bath through a relay (for example, after each heating for 1 hour, the power needs to be turned off for 1-1.5 hours). The present invention operates in an intermittent heating manner, which can greatly reduce energy consumption compared to continuous heating. Intermittent heating allows the system to heat only when needed, which can reduce unnecessary energy consumption and improve energy efficiency.

[0028] Furthermore, preferably, the pH of the wastewater treatment is 7.7-8.5.

[0029] Furthermore, preferably, the wastewater treatment is operated in a continuous flow-in and continuous water-out mode; wherein, stirring is performed for 3-5 minutes every 1.5 hours, and the rotation speed is not higher than 150 r / min.

[0030] The present invention provides a biofilm reactor and ammonia nitrogen wastewater treatment method. By improving the carrier of the biofilm reactor to a tourmaline-based carrier, it is not necessary to maintain a high temperature, so as to effectively promote the release of an electric field by the tourmaline-based carrier; the released electric field is used to adjust the redox potential and reduce the association degree of water molecules, thereby adjusting the permeability of the cell membrane and increasing the activity of dehydrogenase; and finally, the generation of extracellular polymers is jointly promoted, thereby improving the formation and stability of the biofilm. In addition, the carrier of the biofilm reactor based on the tourmaline-based carrier has the characteristics of simple preparation, long service life, and the active components are not easy to lose; only intermittent heating is required, and the energy consumption is relatively low. Finally, the technical effect of improving the biological treatment efficiency of ammonia nitrogen wastewater and reducing operating costs is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic flow chart of a method for preparing a carrier for a biofilm reactor provided in one embodiment of the present invention.

[0032] Figure 2 A physical diagram of the process of a method for preparing a carrier for a biofilm reactor provided in one embodiment of the present invention.

[0033] Figure 3 This is a graph showing changes in ammonia nitrogen concentration in the inlet and outlet water of a biofilm reactor provided by an embodiment of the present invention.

[0034] Figure 4 This is a graph showing changes in nitrite concentration in the inlet and outlet water of a biofilm reactor provided in one embodiment of the present invention.

[0035] Figure 5 This is a graph showing changes in nitrate-nitrogen concentration in the effluent of a biofilm reactor provided in one embodiment of the present invention.

[0036] Figure 6 A graph showing changes in total nitrogen removal load of a biofilm reactor provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0037] The present invention will be described in more detail with reference to the following examples. However, the protection scope of the present invention is not limited to the following examples.

[0038] Among the various experimental supplies mentioned in this article (including but not limited to: chemical reagents, biological products, cells, organisms, instruments, etc.), for those that are special or difficult to obtain, the manufacturers, references or detailed preparation methods have been indicated in the article; those not otherwise specified are conventional experimental supplies and can be easily obtained by various means (such as purchase, self-preparation, etc.) before the date of this application.

[0039] Moving Bed Biofilm Reactor (MBBR) is a new type of sewage treatment equipment that appeared in the mid-1980s. It combines the two processes of activated sludge method and biofilm method. The core is to add suspended fillers with a density close to that of water into the reactor as a carrier for the growth of microorganisms. The fillers are fluidized under the action of aeration and the lifting of water flow in the reactor, and the microorganisms are fully in contact with the wastewater to achieve the effect of sewage treatment.

[0040] Tourmaline's ability to activate water mainly depends on its spontaneous polarization and far-infrared radiation characteristics. The electric field generated by spontaneous polarization and far-infrared rays work together to weaken or even break the hydrogen bonds in the water, thereby activating the water. When the temperature changes, spontaneous polarization occurs, and its own electric field is released. This electric field can also destroy the hydrogen bonds between water molecules, thereby causing the water molecules to electrolyze. This activation can change the structure of water molecules, for example, decomposing large water molecules into small water molecules containing only 5-6 water molecules, thereby reactivating the water. The effects of activated water include reducing the surface tension of water, increasing the rate of dissolved oxygen, increasing the conductivity and evaporation rate, and reducing the pH value of water. These changes make the activated water have better biological effects, such as increasing seed germination rate and cell proliferation.

[0041] The present invention provides a biofilm reactor for treating ammonia nitrogen wastewater; the biofilm reactor comprises a reaction tank and a sedimentation tank which are sequentially connected in the flow direction of the treated wastewater, a tourmaline-based carrier is loaded inside the reaction tank; a water outlet and an air outlet are located at the bottom of the tourmaline-based carrier.

[0042] In a specific implementation process, the tourmaline-based carrier includes tourmaline powder, talc powder, polyethylene powder and flux. Alternatively, the tourmaline-based carrier includes tourmaline powder, talc powder, polyurethane powder and flux. Alternatively, the polyethylene powder may also be at least one of silica gel, polypropylene and polyvinylidene fluoride. Among them, polyethylene powder (HDPE) is a highly crystalline, non-polar thermoplastic resin with a chemical formula of (CH-CH) n Odorless, tasteless, non-toxic white powder or semi-circular particles, melting point is about 131℃, density is 0.942g / cm 3 -0.950g / cm 3 . Organically combining tourmaline and polyethylene materials and controlling the temperature change conditions can effectively enhance the polarization effect of tourmaline, improve cell membrane permeability, promote cell metabolism and increase cell growth, thereby improving the activity and stability of anaerobic ammonia oxidizing bacteria. Furthermore, the mass components of the tourmaline-based carrier are 5-10 parts of tourmaline powder, 100 parts of polyethylene powder, 2-4 parts of talcum powder, and 1-3 parts of flux. It should be noted that the flux can be polyethylene wax; polyethylene wax, as a lubricating dispersant for the raw material, can improve the uniformity and smoothness of the carrier component.

[0043] Preparation Example 1

[0044] Figure 1 and Figure 2 The process of the method for preparing a carrier of a biofilm reactor provided by an embodiment of the present invention is generally described, wherein: Figure 1 A schematic flow chart of a method for preparing a carrier of a biofilm reactor provided in one embodiment of the present invention; Figure 2 A physical diagram of the process of a method for preparing a carrier for a biofilm reactor provided in one embodiment of the present invention.

[0045] The present invention provides a method for preparing a carrier of a biofilm reactor, such as Figure 1 and Figure 2 As shown, the method includes the following steps.

[0046] S110, mixing 10 parts of tourmaline powder, 2 parts of talc powder, 100 parts of polyethylene powder and 1 part of flux according to mass parts.

[0047] S120, melt-extrude the mixed raw materials through a single screw extruder to obtain a molten material.

[0048] S131, water-cooling the extruded long strip of molten material.

[0049] S132, cutting the cooled molten material into granular materials.

[0050] S133, using a single screw extruder with a set die head to perform secondary melt extrusion on the granular material, and then towing and water cooling to form a tourmaline-based carrier 1.

[0051] Preparation Example 2

[0052] The invention provides a method for preparing a carrier of a biofilm reactor, and the method comprises the following steps.

[0053] S110, mixing 5 parts of tourmaline powder, 4 parts of talc powder, 100 parts of polyethylene powder and 2 parts of flux according to mass parts.

[0054] S120, melt-extrude the mixed raw materials through a single screw extruder to obtain a molten material.

[0055] S131, water-cooling the extruded long strip of molten material.

[0056] S132, cutting the cooled molten material into granular materials.

[0057] S133, using a single screw extruder with a set die head to perform secondary melt extrusion on the granular material, and then towing and water cooling to form a tourmaline-based carrier 2.

[0058] Preparation Example 3

[0059] The invention provides a method for preparing a carrier of a biofilm reactor, and the method comprises the following steps.

[0060] S110, mixing 7 parts of tourmaline powder, 3 parts of talc powder, 100 parts of polyethylene powder and 3 parts of flux according to mass parts.

[0061] S120, melt-extrude the mixed raw materials through a single screw extruder to obtain a molten material.

[0062] S131, water-cooling the extruded long strip of molten material.

[0063] S132, cutting the cooled molten material into granular materials.

[0064] S133, using a single screw extruder with a set die head to perform secondary melt extrusion on the granular material, and then towing and water cooling to form a tourmaline-based carrier 3.

[0065] Preparation Example 4

[0066] The invention provides a method for preparing a carrier of a biofilm reactor, and the method comprises the following steps.

[0067] S110, mixing 3 parts of talc powder, 100 parts of polyethylene powder and 3 parts of flux according to mass parts.

[0068] S120, melt-extrude the mixed raw materials through a single screw extruder to obtain a molten material.

[0069] S131, water-cooling the extruded long strip of molten material.

[0070] S132, cutting the cooled molten material into granular materials.

[0071] S133, using a single screw extruder with a set die head to perform secondary melt extrusion on the granular material, and then towing and water cooling to form a tourmaline-based carrier 4.

[0072] Example 1

[0073] The invention provides a method for treating ammonia nitrogen wastewater, which uses a biofilm reactor containing a tourmaline-based carrier obtained in a preparation example to treat the ammonia nitrogen wastewater.

[0074] The inoculum sludge was taken from 1000mgN.m -3 .d -1 The biofilm reactor was operated stably for 2 months under a nitrogen load of 4 groups of biofilm reactors, and the MLSS concentration in each biofilm reactor was not less than 2500 mg / L.

[0075] The tourmaline-based composite carrier 1, tourmaline-based composite carrier 2, tourmaline-based composite carrier 3 and tourmaline-based composite carrier 4 obtained in Preparation Examples 1 to 4 were added to the four groups of reactors respectively, wherein the filling ratios were 30%-35% respectively.

[0076] The water used in the embodiment is artificial simulated wastewater, the influent matrix is ​​provided by (NH4)2SO4 and NaNO2, and the concentration of ammonia nitrogen and nitrite nitrogen is maintained at about 100 mg / L. The remaining components of the influent are shown in Tables 1 and 2, which are KH2PO4, MgSO4.7H2O, CaCl2.2H2O, NaHCO3 and trace elements.

[0077] Table 1 Simulated wastewater quality table

[0078]

[0079] Table 2 Trace elements

[0080]

[0081] The biofilm reactor is operated under variable temperature conditions, the water bath is controlled to work intermittently by a relay (power off for 1-1.5 hours after each heating hour), the pH is controlled between 7.7-8.5, and the biofilm reactor is strictly protected from light. The embodiment adopts a continuous flow in and out mode, stirring for 3-5 minutes every 1.5 hours, and the speed is not higher than 150r / min. Among them, the variable temperature condition is to control the temperature to change between room temperature and 37°C.

[0082] After the biofilm reactor was operated for 30 days, the four groups of wastewater in the embodiment were sampled and the inlet and outlet ammonia nitrogen concentration change detection of the biofilm reactor, the inlet and outlet nitrite concentration change detection of the biofilm reactor, the outlet nitrate nitrogen concentration change detection of the biofilm reactor and the total nitrogen removal load change detection of the biofilm reactor were respectively performed. The results show that the total nitrogen removal capacity of the biofilm reactor corresponding to the tourmaline-based composite carrier 1, tourmaline-based composite carrier 2 and tourmaline-based composite carrier 3 obtained in Preparation Examples 1 to Preparation Examples 3 is significantly better than that of Preparation Example 4, indicating that the use of tourmaline-based carriers is effective in improving the total nitrogen removal load.

[0083] The mean values ​​of the inlet and outlet water ammonia nitrogen concentration change detection of the biofilm reactor corresponding to the tourmaline-based composite carrier 1, tourmaline-based composite carrier 2 and tourmaline-based composite carrier 4 obtained in Preparation Example 1-Preparation Example 2 and Preparation Example 4, the inlet and outlet water nitrite concentration change detection of the biofilm reactor, the outlet water nitrate nitrogen concentration change detection of the biofilm reactor and the total nitrogen removal load change detection of the biofilm reactor were compared with the corresponding data of the comparative example to obtain the inlet and outlet water ammonia nitrogen concentration change graph, the inlet and outlet water nitrite concentration change graph, the outlet water nitrate nitrogen concentration change graph and the total nitrogen removal load change graph.

[0084] like Figure 3 As shown, the test results of the change of ammonia nitrogen concentration in the inlet and outlet water of the biofilm reactor show that, compared with Preparation Example 4 (adding 0% tourmaline), the biofilm reactor of the tourmaline-based composite carrier of Preparation Example 1 has a lower ammonia nitrogen concentration in the outlet water and an improved removal rate after continuous operation for a certain period of time. This shows that tourmaline can increase the start-up speed of contact oxidation treatment of petrochemical wastewater and increase the ammonia nitrogen removal efficiency.

[0085] like Figure 4 As shown, the detection results of the change of nitrite concentration in the inlet and outlet water of the biofilm reactor show that for Preparation Example 4, after the biofilm reactor with the tourmaline-based composite carrier of Preparation Example 1 has been running continuously for a certain period of time, the biofilm reactor with the tourmaline-based composite carrier can improve the activity of the biofilm, accelerate the electron transfer in the respiration process, promote the decomposition of organic carbon sources, and reduce the concentration of nitrite in the outlet water of the biofilm reactor.

[0086] like Figure 5 As shown, the detection results of the change of nitrate-nitrogen concentration in the effluent of the biofilm reactor show that for Preparation Example 4, after the biofilm reactor with the tourmaline-based composite carrier of Preparation Example 1 has been running continuously for a certain period of time, the biofilm reactor with the tourmaline-based composite carrier has a promoting effect on the removal of nitrate-nitrogen.

[0087] like Figure 6 As shown in the figure, the total nitrogen removal load change test results of the biofilm reactor show that for Preparation Example 4, the biofilm reactor of the tourmaline-based composite carrier of Preparation Example 1 has been running continuously for a certain period of time. However, from the perspective of the improvement of the total nitrogen removal capacity of the experimental group and the control group, the removal capacity of the total nitrogen by adding 10% tourmaline carrier increased from 986.54±68.30mgN.m - 3 .d -1 Increased to 1180.68±23.12mgN.m -3 .d -1 , increased by 19.68%; adding 5% tourmaline carrier to increase the total nitrogen removal capacity from 980.11±68.95mgN.m -3 .d -1 Increased to 1154.42±76.82mgN.m -3 .d -1， The total nitrogen removal load of the carrier without tourmaline increased by 15.10% from 985.93±84.74mgN.m -3 .d -1 Increased to 1128.87±28.18mgN.m -3 .d -1The total nitrogen removal capacity of the carrier containing 10% tourmaline was significantly better than that of the control group, indicating that the use of tourmaline-based carriers is effective in increasing the total nitrogen removal load.

[0088] In summary, the present invention provides a biofilm reactor and ammonia nitrogen wastewater treatment method. By improving the carrier of the biofilm reactor to a tourmaline-based carrier, it is not necessary to maintain a high temperature, so as to effectively promote the release of the electric field based on the tourmaline carrier; the released electric field is used to regulate the redox potential and reduce the association degree of water molecules, thereby regulating the permeability of the cell membrane and increasing the activity of dehydrogenase; and finally jointly promote the formation of extracellular polymers, thereby improving the formation and stability of the biofilm. In addition, the carrier of the biofilm reactor based on the tourmaline-based carrier has the characteristics of simple preparation, long service life, and the active components are not easy to lose; only intermittent heating is required, and the energy consumption is relatively low. Finally, the technical effect of improving the biological treatment efficiency of ammonia nitrogen wastewater and reducing operating costs is achieved.

[0089] Although the present invention has been described in detail above by general description, specific implementation methods and experiments, it is obvious to those skilled in the art that some modifications or improvements can be made on the basis of the present invention. Therefore, these modifications and improvements made on the basis of not departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A biofilm reactor, characterized in that: Used for treating ammonia nitrogen wastewater; the biofilm reactor comprises a tourmaline-based carrier.

2. The biofilm reactor according to claim 1, characterized in that The tourmaline-based carrier includes tourmaline powder, talc powder, polyethylene powder and flux.

3. The biofilm reactor according to claim 2, characterized in that The mass components of the tourmaline-based carrier are 5-10 parts of tourmaline powder, 100 parts of polyethylene powder, 2-4 parts of talc powder and 1-3 parts of flux.

4. A method for preparing a carrier of a biofilm reactor, characterized in that: Methods include, Mixing tourmaline powder, talcum powder, polyethylene powder and flux; The mixed raw materials are melt-extruded through a single screw extruder to obtain a molten material; The molten material is processed to obtain a tourmaline-based carrier.

5. The method for preparing a carrier of a biofilm reactor according to claim 4, characterized in that: The method of obtaining a tourmaline-based carrier by processing the molten material comprises: The extruded long strip of molten material is water-cooled and formed; Cutting the cooled molten material into granular materials; The granular material is subjected to secondary melt extrusion by a single screw extruder with a set die head, followed by traction and water cooling to form a tourmaline-based carrier.

6. A method for treating ammonia nitrogen wastewater, characterized in that: Ammonia nitrogen wastewater treatment is carried out using the biofilm reactor comprising a tourmaline-based carrier as described in claim 1.

7. The method for treating ammonia nitrogen wastewater according to claim 6, characterized in that: The filling ratio of the tourmaline-based carrier is 25% to 40%.

8. The method for treating ammonia nitrogen wastewater according to claim 6, characterized in that: The biofilm reactor treats wastewater under variable temperature conditions in a light-shielded and closed environment; wherein the variable temperature conditions are to control the temperature to vary between room temperature and 37°C.

9. The method for treating ammonia nitrogen wastewater according to claim 6, characterized in that: The pH for wastewater treatment is 7.7-8.

5.

10. The method for treating ammonia nitrogen wastewater according to claim 6, characterized in that: The wastewater treatment is operated in a continuous flow-in and continuous water-out mode; stirring is performed for 3-5 minutes every 1.5 hours, and the rotation speed is not higher than 150r / min.

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