Immobilized photosynthetic bacteria bioreactor for treating high-salinity organic wastewater

Abstract

The invention discloses an immobilized photosynthetic bacteria biological rotating brush reactor for treating high-salt organic wastewater, comprising a reaction tank and a rotating brush device, wherein the reaction tank is a rectangular reinforced concrete structure, the brush roller is parallel to the wide side of the reaction tank and is installed on the water surface of the reaction tank, half of the brush roller is immersed in water, and half is exposed to the air, one end of the main shaft is connected to the motor through a bearing, a sealing sleeve, a coupling, and a transmission device, and the other end of the main shaft is connected to a bearing seat, the main shaft drives the brush roller to rotate, and a basic support seat is provided at the bottom of the motor and the bearing seat. The biological rotating brush reactor increases the biomass of photosynthetic bacteria, and performs micro-aeration by slow rotation, which is convenient for bacterial recovery. During the rotation process, a photosynthetic bacteria immobilized biofilm will be formed on the brush surface of the roller, and it will receive light and absorb oxygen with the rotation cycle, degrade organic matter, and make salt-tolerant photosynthetic bacteria grow dominantly, which is suitable for treating high-salt organic industrial wastewater.

Description

Technical Field

[0001] The invention relates to a sewage treatment device, in particular to an immobilized photosynthetic bacteria bioreactor for treating high-salt organic wastewater. Background Art

[0002] The salt content of high-salt wastewater is usually between 5% and 20%, and the COD content is greater than 1000 mg / L, such as dye chemical wastewater, petroleum processing wastewater, seawater flushing wastewater, etc. It is difficult for microorganisms in ordinary bioreactors to adapt to such a high-salt environment. It needs to be diluted and domesticated for a long time, and undergo multiple graded treatments such as anaerobic and aerobic processes to meet the discharge standards. It has the disadvantages of complex process flow, large footprint, high investment and operating costs, low shock load resistance, and large sludge production, which affects the application of biological methods in the purification of high-salt wastewater.

[0003] Photosynthetic bacteria (PSB) are isolated, extracted and cultured from seawater. They have a certain salt tolerance and are suitable for survival in environments with high salt content. PSB is a type of prokaryotic microorganism with a primitive light energy synthesis system. It belongs to Gram-negative bacteria and has rod-shaped, spherical, semi-circular and spiral shapes with a diameter of 0.3-2.6μm. Photosynthetic bacteria have chromatophores that can perform photosynthesis in their cells. These chromatophores are spherical or cellular bodies with a diameter of about 600 to 1000A differentiated from cell membranes, which contain bacterial chlorophyll and carotenoids and can perform photosynthetic phosphorylation and photooxidation-reduction reactions. In aerobic darkness, bacteria lack this chromatophore and at this time carry out organic acid metabolism through the TC (tricarboxylic acid cycle) cycle; in anaerobic light, chromatophores are quickly formed and metabolic pathways are quickly converted, closely combining the redox reaction of organic acid dissimilation and assimilation with the photooxidation-reduction reaction. Some species of Rhodospirillaceae are commonly used in wastewater treatment. Their cell structure and unique material and energy metabolism enable them to show unparalleled superiority in the treatment of high-concentration salt-containing organic wastewater. At the same time, photosynthetic bacteria have high economic value and can be recycled. The protein content of photosynthetic bacterial cells reaches 30% to 80% of the cell dry weight, the mass concentration of coenzyme Q10 reaches 88.8mg / g, and it also contains 5-ALA and pigments, etc., which are high-quality biomaterials that can be used in health and medical fields.

[0004] The photosynthetic bacteria reactor must meet the following conditions: (1) Light: Light of appropriate intensity is a necessary condition for cultivating photosynthetic bacteria and rejuvenating the bacteria. Light combined with anaerobic conditions can promote the growth and reproduction of photosynthetic bacteria. (2) Oxygen supply: Trace oxygen supply is an important condition to ensure the dominant growth of photosynthetic bacteria. Trace oxygen supply can effectively inhibit the growth of anaerobic bacteria and sulfate reduction on the one hand, and on the other hand, it can limit the excessive growth of aerobic bacteria, maintain the proper growth of alkaline and aerobic bacteria, decompose large molecular organic matter, and create a good environmental condition for the growth of photosynthetic bacteria. Photosynthetic bacteria can maintain dominant growth in the reactor under micro-oxygen conditions (0.5-1.0 mg / L). (3) Bacteria recovery: The reactor structure should facilitate the collection and concentration of photosynthetic bacteria.

[0005] The photosynthetic bacteria reactors reported so far mainly include completely mixed suspended reactors, submerged biological contact fixed film reactors, biological rotating disk reactors, biological cage reactors, etc. Among them, the completely mixed reactors and submerged biological contact fixed film reactors have the problem of insufficient light for photosynthetic bacteria due to the obstruction of water depth and limited light penetration depth; the biological rotating disk reactor has the problems of small amount of biofilm attached to the disk surface, easy to fall off, and easy hybridization of bacteria; the biological cage reactor has a large amount of filler filled in the cage, and the photosynthetic bacteria also have the problem of insufficient light. Summary of the invention

[0006] The purpose of the present invention is to provide an immobilized photosynthetic bacteria bioreactor for treating high-salt organic wastewater, so as to solve the problems of the existing reactors in the above-mentioned background technology, such as water depth obstruction, limited light penetration depth, insufficient light for photosynthetic bacteria, and easy hybridization of bacteria.

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: an immobilized photosynthetic bacteria biological rotating brush reactor for treating high-salt organic wastewater comprises a reaction tank and a rotating brush device, wherein the rotating brush device is composed of a motor, a transmission device, a coupling, a main shaft, a brush roller, a bearing, a sealing sleeve and a bearing seat, the reaction tank is a rectangular reinforced concrete structure, the brush roller is parallel to the wide side of the reaction tank and is installed on the water surface of the reaction tank, half of the brush roller is immersed in water and half is exposed to the air, one end of the main shaft is connected to the motor through a bearing, a sealing sleeve, a coupling and a transmission device, and the other end of the main shaft is connected to the bearing seat, the main shaft drives the brush roller to rotate, and a basic support seat is arranged at the bottom of the motor and the bearing seat.

[0008] Preferably, the reaction tank is designed and calculated according to the relevant bioreactor sludge organic load or hydraulic retention time parameters, and multiple reactors can be operated in parallel or in series. The recommended dimensions of a single reaction tank are: length: 5000-10000mm, width: 2000-3000mm, effective water depth 2000-3000mm, and pool top extra height: 400mm.

[0009] Preferably, the outer diameter of the brush roller is 500-700 mm, the outer surface of the brush roller is planted with polyurethane brush filaments with a length of 150 mm, and the outer diameter of the roller shaft is 200-400 mm.

[0010] Preferably, the length of the brush roller is flexibly determined according to the width of the reaction tank, leaving a gap of 100 mm with the tank wall, and the roller shaft of the brush roller is a hard PVC with an iron pipe buried in the center.

[0011] Preferably, the brush rollers are arranged in parallel in several groups in the reaction tank.

[0012] Preferably, the power of the motor is determined according to the length of the brush roller and is between 7.5 and 11 kW.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: the present biological rotating brush reactor overcomes the problem of insufficient light in the photosynthetic bacteria reactor of the above reactor, increases the biomass of photosynthetic bacteria, and can perform micro-aeration through slow rotation, which is convenient for bacterial recovery. Its key component is the brush roller driven by the speed regulating motor. During the rotation process, a photosynthetic bacteria immobilized biofilm will be formed on the brush on the roller surface, half of which is immersed in water and half is exposed to the air, and it is constantly replaced with the rotation. The photosynthetic bacteria can repeatedly receive light, absorb oxygen, degrade organic matter, and maintain dominant growth;

[0014] The reactor has the following advantages: 1. When the brush is exposed to the air, the microorganisms can absorb oxygen in the atmosphere to metabolize pollutants and bring oxygen into the sewage through the rotation of the brush; when the brush enters the water, the microorganisms degrade organic matter under dark micro-aerobic conditions, thereby reducing the cost of mechanical aeration in the biological treatment of wastewater;

[0015] 2. The photosynthetic bacteria on the brush on the disk can repeatedly use the light in the air to grow and reproduce during the rotation process, solving the problem of insufficient light absorption.

[0016] 3. The brush is a polyurethane filament, which is not easy to corrode, light in weight, and has a large specific surface area, so it can attach a large amount of biofilm;

[0017] 4. When the biomass is saturated, the brush roller can be removed and replaced as a whole, and the photosynthetic bacteria can be collected by centrifugation in a suitable high-speed centrifuge device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the present invention;

[0019] Figure 2 This is a schematic diagram of the connection structure between the main shaft and the brush roller in the present invention;

[0020] Figure 3This is a schematic diagram of the brush roller state after the reactor is successfully started in an embodiment of the present invention;

[0021] Figure 4 This is a schematic diagram of the COD removal of high-salt organic wastewater - gelatin production wastewater by PSB in an embodiment of the present invention.

[0022] In the figure: reaction tank 1, rotating brush device 2, motor 2-1, transmission device 2-2, coupling 2-3, main shaft 2-4, brush roller 2-5, bearing 2-6, sealing sleeve 2-7, bearing seat 2-8. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] See also Figure 1-2 In this embodiment, the immobilized photosynthetic bacteria biological brush-turning reactor for treating high-salt organic wastewater comprises a reaction tank 1 and a brush-turning device 2, wherein the brush-turning device is composed of a motor 2-1, a transmission device 2-2, a coupling 2-3, a main shaft 2-4, a brush roller 2-5, a bearing 2-6, a sealing sleeve 2-7 and a bearing seat 2-8. The reaction tank 1 is a rectangular reinforced concrete structure, the brush roller 2-5 is parallel to the wide side of the reaction tank 1 and is installed on the water surface of the reaction tank 1, half of the brush roller 2-5 is immersed in water and half is exposed to the air, one end of the main shaft 2-4 is connected to the motor 2-1 through a bearing 2-6, a sealing sleeve 2-7, a coupling 2-3, and a transmission device 2-2, and the other end of the main shaft 2-4 is connected to the bearing seat 2-8, the main shaft 2-4 drives the brush roller 2-5 to rotate, and a basic support seat a is provided at the bottom of the motor 2-1 and the bearing seat 2-8.

[0025] The dimensions of the reaction pool 1 described in this embodiment are as follows: length: 5000 mm, width: 2000 mm, effective water depth: 2000 mm, and pool top super height: 400 mm.

[0026] The outer diameter of the brush roller 2-5 in this embodiment is 500mm, its outer surface is planted with polyurethane brush filaments with a length of 150mm, and the outer diameter of the roller shaft is 200mm.

[0027] In this embodiment, the brush rollers 2-5 are arranged in parallel in a group in the reaction tank.

[0028] The working principle of this embodiment is as follows: start the device, the motor 2-1 drives the brush roller 2-5 to rotate slowly for micro-aeration, and during the rotation, a photosynthetic bacteria immobilized biofilm is formed on the surface of the brush roller 2-5, half of which is immersed in water and half is exposed to the air, and it is constantly replaced with the rotation; when the brush roller 2-5 is exposed to the air, the microorganisms can absorb oxygen in the atmosphere to metabolize pollutants, and bring oxygen into the sewage through the rotation of the brush roller 2-5; when the brush roller 2-5 enters the water, the microorganisms degrade the pollutants under the dark micro-oxygen conditions. organic matter, thereby reducing the cost expenditure caused by mechanical aeration in the process of biological treatment of wastewater; and the photosynthetic bacteria on the brush roller 2-5 can repeatedly use the light in the air to grow and reproduce during the rotation process, solving the problem of insufficient light absorption and facilitating the advantageous growth of photosynthetic bacteria; the brush of the brush roller 2-5 is a polyurethane filament, which is not easy to corrode, light in weight, and has a large specific surface area of ​​the filament, and can attach a large amount of biofilm; when the biomass is saturated, the brush roller 2-5 can be removed and replaced as a whole, and the photosynthetic bacteria can be collected by centrifugation in a suitable high-speed centrifugal device.

[0029] The setting of the reactor operating parameters in this embodiment: Brush roller 2-5 speed: Brush roller 2-5 rotates at a low speed, and the outer edge linear speed of the brush is less than 0.2m / s to ensure that the brush does not cause splashing when entering the water. The speed range is 0.5-3rpm. Dissolved oxygen: Natural aeration is carried out by rotating the brush. By adjusting the speed, the dissolved oxygen is ensured to be in a micro-oxygen state of 0.5-1.0mg / L. Lighting: The reactor uses natural light during the day and fluorescent light at night. The light intensity is 1600-2000Lx.

[0030] Inoculation solution: Rhodospirillaceae photosynthetic bacteria solution can be purchased through commercial channels, and the initial inoculation amount is 10% to 20% (volume ratio);

[0031] Reactor startup: High-salinity organic wastewater is diluted to a COD of less than 500 mg / L, injected into the reaction tank to the effective water depth, the motor is started, and the photosynthetic bacteria stock solution is inoculated. It is first cultured in static water for 3 days, and then the COD concentration of the wastewater is increased to the original concentration according to the gradient. It is cultured at a low flow rate for 7 to 15 days. A light red photosynthetic bacterial biofilm can be observed on the brush, as shown below Figure 3 As shown, the reactor can be considered to be started successfully.

[0032] Collect and concentrate photosynthetic bacteria: After the rotating brush runs for a certain period of time, the photosynthetic bacteria can be collected as needed. The method is to replace the rotating brush with a new one, place the rotating brush removed from the reactor in a closed centrifugal device, and centrifuge to collect photosynthetic bacteria at a speed of 500-1000rpm.

[0033] Verify the high-concentration salt-containing organic wastewater treatment effect of the reactor in this embodiment:

[0034] The water sample selected was high-concentration salt-containing organic wastewater, which was taken from the calcium hydrogen phosphate production wastewater of a gelatin company. The original water quality of the calcium hydrogen phosphate water is shown in Table 1.

[0035] Table 1 Water quality of phosphate-calcium water after adjustment

[0036]

[0037] The source of photosynthetic bacteria (PSB) strains, the photosynthetic bacteria comes from the photosynthetic bacteria liquid fertilizer produced by a certain biological fertilizer products company.

[0038] Biofilm formation starts; PSB bacterial solution inoculation ratio is V PSB / V 水 =1:9.

[0039] First, dilute the original water sample 3 times for static culture. After 3 days, gradually increase the proportion of phosphate and calcium water. After the biofilm is successfully formed, change all of it to phosphate and calcium wastewater.

[0040] Treatment effect; COD removal: Two groups of photosynthetic bacteria reactors PSB1 and PSB2 were used for parallel experiments to verify each other, denoted as p1 and p2. The reaction results are shown in Figure 3 shown.

[0041] Figure 4 This is the COD removal effect of PSB.

[0042] Depend on Figure 4 It can be seen that in the two parallel tests of P1 and P2, COD decreased continuously with the extension of hydraulic retention time (HRT). When the hydraulic retention time was 60h, the COD removal rate could reach more than 85%, and more than 92% at 84h. After 96h reaction, the COD of the effluent of P1 was 189mg·L -1 , P2 is 203 mg·L -1 For high-concentration phosphate-calcium wastewater, achieving this treatment effect is a breakthrough, indicating that photosynthetic bacteria have a good degradation effect on phosphate-calcium water.

[0043] Tolerance of photosynthetic bacteria to chloride ions. As can be seen from Table 1, the concentration of chloride ions in phosphate-calcium wastewater is close to 30,000 mg / L, but the chloride ions do not inhibit the photosynthetic bacteria during the treatment process, indicating that the photosynthetic bacteria from the ocean can tolerate high concentrations of Cl - , strong salt resistance.

[0044] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for treating high-salinity organic wastewater using an immobilized photosynthetic bacteria bioreactor, characterized in that: The reactor comprises a reaction tank (1) and a rotating brush device (2), wherein the rotating brush device (2) is composed of a motor (2-1), a transmission device (2-2), a coupling (2-3), a main shaft (2-4), a brush roller (2-5), a bearing (2-6), a sealing sleeve (2-7) and a bearing seat (2-8), the reaction tank (1) is a rectangular reinforced concrete structure, and the brush roller (2-5) is parallel to the wide side of the reaction tank (1) and is installed on the water surface of the reaction tank (1). , half of the brush roller (2-5) is immersed in water and the other half is exposed to air; one end of the main shaft (2-4) is connected to the motor (2-1) through a bearing (2-6), a sealing sleeve (2-7), a coupling (2-3), and a transmission device (2-2); the other end of the main shaft (2-4) is connected to a bearing seat (2-8); the main shaft (2-4) drives the brush roller (2-5) to rotate; a basic support seat (a) is provided at the bottom of the motor (2-1) and the bearing seat (2-8); The reaction tank (1) is designed and calculated according to the relevant bioreactor sludge organic load or hydraulic retention time parameters. Multiple reactors are operated in parallel or in series. The dimensions of a single reaction tank (1) are: length: 5000-10000 mm, width: 2000-3000 mm, effective water depth: 2000-3000 mm, and pool top super height: 400 mm. The outer diameter of the brush roller (2-5) is 500-700 mm, the outer surface of the brush roller is planted with polyurethane brush filaments with a length of 150 mm, and the outer diameter of the roller shaft is 200-400 mm; The length of the brush roller (2-5) is determined according to the width of the reaction pool (1), leaving a gap of 100 mm between the brush roller and the pool wall; the roller shaft of the brush roller (2-5) is a hard PVC with an iron pipe buried in the center; The brush rollers (2-5) are arranged in parallel in a plurality of groups in the reaction tank (1); The power of the motor (2-1) is determined according to the length of the brush roller (2-5), and is between 7.5 and 11 kW. When the reactor is started, the motor (2-1) drives the brush roller (2-5) to rotate slowly for micro-aeration, so as to facilitate bacterial recovery. During the rotation process, a photosynthetic bacteria immobilized biofilm is formed on the surface of the brush roller (2-5), half of which is immersed in water and the other half is exposed to the air, and the biofilm is continuously replaced with the rotation. When the brush roller (2-5) is exposed to the air, the microorganisms can absorb oxygen in the atmosphere to carry out pollutant metabolism activities, and bring oxygen into the sewage through the rotation of the brush roller (2-5). When the brush roller (2-5) enters the water, the microorganisms degrade organic matter under dark micro-oxygen conditions, thereby reducing the cost expenditure caused by mechanical aeration during the biological treatment of wastewater; and the photosynthetic bacteria on the brush roller (2-5) can repeatedly use natural light to grow and reproduce during the rotation process, solving the problem of insufficient light absorption and facilitating the dominant growth of photosynthetic bacteria; the brush of the brush roller (2-5) is a polyurethane filament, which is not easy to corrode, light in weight, and has a large specific surface area of ​​the filament, and can attach a large amount of biofilm; when the biomass is saturated, the brush roller (2-5) can be removed and replaced as a whole, and the photosynthetic bacteria can be collected by centrifugation in a suitable high-speed centrifuge device.

Images