Compact rotary-type algae biofilm reactor

Abstract

To provide a compact rotary-type algae biofilm reactor that can improve utilization rate of the sunlight, can markedly improve the amount of biomass per unit area and unit space, is further favorable in improving treatment efficiency, and enhances economical efficiency without requiring additional aerators.SOLUTION: A reactor includes an algae biofilm module and an optical guide module. The algae biofilm module includes a plurality of rotary members and a reaction pool, an algae biofilm growth vector 2 and a power transmission belt in the rotary member are wound around a drive shaft 3 and a follower shaft 4, the rotary member is fixed to a fixing frame 6 at the top and is dipped with the bottom end in the reaction pool 5, a low speed motor 1 drives the rotary member to rotate, an optical guide module includes a rotatable lens holder 11 fixedly provided at the top edge with a linear fresnel lens 12 and provided at the bottom edge with a light guide plate 13, and the linear fresnel lens is provided at one side with a stepping motor 10.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a compact rotating algae biofilm reactor, which belongs to the technical field of sewage treatment. [Background technology]

[0002] In order to overcome the challenges of pollution prevention and treatment and consolidate the concept of green development during the 14th Five-Year Plan period, the requirements for increasing the collaborative effect of pollution and carbon emission reduction in sewage treatment are put forward. At present, the mainstream sewage treatment technology is based on the activated sludge method, which has the problem of high energy consumption and drug consumption, which is contrary to the development direction of low-carbon transformation in the sewage treatment industry. In recent years, sewage treatment technology based on microalgae has been widely noted for its advantages such as efficient removal of pollutants (nitrogen, phosphorus, heavy metals, drugs, etc.), fixation of CO2, and production of biofuel, and has the prospect of widespread application. The algae biofilm form is used to further break through the problem of the difficulty of biomass collection in the suspended type microalgae treatment technology. However, the traditional algae biofilm technology still has the problems of low material content and low load per unit area. Therefore, it is necessary to develop a more efficient compact algae biofilm reactor.

[0003] CN108163972A discloses an algae rotating biofilm reactor system and application based on phosphorus removal denitrification, which first fixes a flexible vector with algae biofilm pre-hanging on a rotatable transmission belt type device, and places the rotating device above an activated sludge pool, and makes the bottom of the rotating part contact with wastewater and activated sludge to form a bond with the activated sludge to remove organic matter, nitrogen, phosphorus and other substances in the sewage, and the upper end of the rotating part is exposed to sunlight and air, and the algae produce oxygen and grow through photosynthesis. The above method has the following problems: (1) A large distance needs to be secured between the rotating parts vertically arranged in the algae biofilm system to avoid mutual shielding, which limits the amount of algae biofilm per unit area to ensure that the algae biofilm on each rotating part receives sufficient light irradiation, and indirectly increases the site area of ​​the device. (2) The irradiation angle of sunlight changes with time, and the treatment effect is likely to become unstable due to uneven light irradiation. When the angle of incidence of the sun is large (morning and evening), the films tend to shield each other, while when the angle of incidence of the sun is small, a large amount of sunlight is directly irradiated into the gaps between the rotating parts, resulting in a low utilization rate of sunlight.(3) In order to combine the algal biofilm and the activated sludge, a large amount of energy needs to be consumed through aeration, which makes it difficult to fully utilize the advantages of the synergistic effect of the pollution reduction and carbon reduction of the algal biofilm, and the algal biofilm is easily detached by aeration, and the activated sludge is easily attached to the algal biofilm during the contact process, which is also detrimental to the photosynthetic function of the algal biofilm.

[0004] Some inventions use light guide plates to improve the light irradiation inside the reactor and increase the growth of algae biofilm. For example, CN111647501A discloses a multi-layered adsorption-type microalgae biofilm photobioreactor based on a light guide vector. The reactor is composed of multi-layered solid light guide plates, and an LED lamp strip is attached to the left side of each solid light guide plate. The light guide plate serves as a light source transmission, a conversion medium, and an adsorption-type microalgae biofilm vector to realize multi-layered culture of microalgae cells and improve the microalgae biomass production per unit area. In addition, CN112852588A discloses a light-guiding three-dimensional porous biofilm-based reactor and a method for culturing microalgae biofilm. The reactor body is equipped with a light-guiding biofilm vector with a three-dimensional porous structure, and the light-guiding biofilm in each layer is fitted with a side-guiding optical fiber and connected to a fiber-dedicated light source through a fiber collector, and the light-guiding nanoparticles are uniformly added into the light-guiding biofilm, and the light-guiding nanoparticles uniformly scatter the light received by the side-guiding optical fiber in all directions. However, these methods require a fixed light-guiding plate, have a narrow light-entering end, and cannot effectively utilize the sunlight with its constantly changing angle, so they can only use fixed artificial light sources (such as LED lamp strips and fibers), which will undoubtedly increase the operating cost and are not in line with the concept of low carbon. Summary of the Invention [Problem to be solved by the invention]

[0005] Object of the invention: The object of the present invention is to provide a compact rotating algae biofilm reactor, which is equipped with a light-guiding module to improve the utilization efficiency of sunlight, allows the installation distance of the vertically rotating algae biofilm vector to be closer, and does not need to rely on activated sludge systems, which can significantly improve the amount of biomass per unit area, thereby improving the efficiency of sewage treatment and algae production, and realizing high-efficiency and low-carbon treatment of sewage. [Means for solving the problem]

[0006] Technical solution: The compact rotating algal biofilm reactor described in the present invention is composed of an algal biofilm module and a light-guiding module interlocked together, the algal biofilm module includes a plurality of rotating members and a reaction pool, a fixed frame is provided on the upper part of the reaction pool, the rotating members include a low-speed motor, an algal biofilm growth vector and a power transmission belt, the low-speed motor is fixed on the upper part of the fixed frame, a driving shaft is connected to one side of the low-speed motor, a driven shaft is provided below the liquid level in the reaction pool, the algal biofilm growth vector is wound around the driving shaft and the driven shaft by the power transmission belt, the light-guiding module includes a rotatable lens holder, a linear Fresnel lens is fixedly provided on the upper end of the rotatable lens holder, a light-guiding plate is provided on the lower end of the rotatable lens holder, a stepping motor is provided on one side of the linear Fresnel lens, and the stepping motor is provided on the fixed frame.

[0007] Furthermore, the number of the rotating members is two or more.

[0008] Furthermore, the linear Fresnel lens can be moved by a stepping motor to rotate slowly with the change in the angle of the sunlight, and always focuses the sunlight linearly on one side of the light guide plate to form a surface light source on the light guide plate, and the light guide plate is fixed in parallel between adjacent rotating members.

[0009] Furthermore, the linear Fresnel lenses are provided on the top of two adjacent rotating members, and the light guide plate is inserted vertically in the middle of the adjacent rotating members and parallel to the surface of the algal biofilm growth vector.

[0010] Furthermore, the base of the rotatable lens holder is in the shape of a human.

[0011] Additionally, the algal biofilm growth vector is a flexible material.

[0012] Moreover, the flexible material is a silica gel film, a nylon cloth, a cotton or linen product or a flexible plastic.

[0013] Furthermore, the low speed motor is connected to a drive shaft for rotation, and the power transmission belt drives a driven shaft that is immersed below the liquid surface of the reaction pool so as to rotate, thereby allowing the algal biofilm growth vector to rotate alternately in the air-liquid medium following the power transmission belt.

[0014] Furthermore, the stepping motor and the low-speed motor may be disposed on the same side of the fixed frame, or may be disposed on different sides.

[0015] Furthermore, a water inlet is provided at the bottom of one side of the reaction pool, and a drain is provided at the other side opposite to the water inlet. Effect of the Invention

[0016] The beneficial effects are as follows: Compared with the prior art, the present invention has the following significant advantages:

[0017] (1) By redirecting the light irradiation, the present invention makes full use of the internal space of the algae biofilm reactor, and allows more rotating members to be installed using the same site area and vertical space, which significantly improves the biomass yield and is favorable for improving the treatment efficiency.

[0018] (2) The present invention improves the utilization rate of sunlight, reduces the problem of uneven light irradiation caused by changes in the incident angle of sunlight and mutual shadowing between adjacent algal biofilms, and is advantageous in improving the stability of the reactor.

[0019] (3) The biological system of the present invention has a simple configuration, prevents sludge from adhering to the algal biofilm and causing blockage, and does not require an additional aeration device, thereby reducing the risk of the algal biofilm falling off due to aeration, and also saving electricity consumption due to additional aeration, thereby enhancing economy. [Brief description of the drawings]

[0020] [Figure 1] FIG. 2 is a front view of an algal biofilm module in the compact rotating algal biofilm reactor of the present invention. [Diagram 2] FIG. 2 is a left side view of the algal biofilm module in the compact rotating algal biofilm reactor of the present invention. [Diagram 3] FIG. 2 is a top view of an algal biofilm module in the compact rotating algal biofilm reactor of the present invention. [Figure 4] FIG. 2 is a front view of the light-guiding module in the compact rotating algal biofilm reactor of the present invention. [Diagram 5] FIG. 2 is a left side view of the light-guiding module in the compact rotating algal biofilm reactor of the present invention. [Figure 6] FIG. 2 is a plan view of the light-guiding module in the compact rotating algal biofilm reactor of the present invention. [Figure 7] FIG. 2 is a principle diagram of the light-guiding module in the compact rotating algae biofilm reactor of the present invention. [Figure 8] FIG. 1 is a front view of the compact rotating algal biofilm reactor of the present invention. [Figure 9] FIG. 2 is a left side view of the compact rotating algal biofilm reactor of the present invention. [Figure 10] FIG. 1 is a plan view of the compact rotating algal biofilm reactor of the present invention. [Figure 11] FIG. 2 is a front view of the compact rotating algal biofilm reactor in Example 1. [Figure 12] FIG. 2 is a left side view of the compact rotating algal biofilm reactor in Example 1. [Figure 13] FIG. 2 is a plan view of the compact rotating algal biofilm reactor in Example 1. [Figure 14] FIG. 2 is an effect diagram of the compact rotating algae biofilm reactor in Example 2 treating sewage. [Figure 15]13 is a graph showing the effect of the algal biofilm reactor treating sewage after the light-guiding module in Example 3 is removed, and the change in the growth status of the algal biofilm. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The technical solution of the present invention will be further described below with reference to the drawings.

[0022] The compact rotating algal biofilm reactor described in the present invention is constructed by fitting an algal biofilm module and a light-guiding module, as shown in FIG. 1-6. As shown in FIG. 1-3, the algal biofilm module includes a plurality of rotating members and a reaction pool 5, a fixed frame 6 is provided on the upper part of the reaction pool 5, the rotating members include a low-speed motor 1, an algal biofilm growth vector 2, a driving shaft 3, a driven shaft 4 and a power transmission belt 9, the low-speed motor 1 is fixed on the upper part of the fixed frame 6, one side of the low-speed motor 1 is connected to the driving shaft 3, the driven shaft 4 is provided below the liquid level in the reaction pool 5 and is installed perpendicular to the driving shaft 3. The algal biofilm growth vector 2 is wound around the driving shaft 3 and the driven shaft 4 by the power transmission belt 9, a water inlet 8 is provided at the bottom of one side of the reaction pool 5, and a drain 7 is provided on the other side opposite to the water inlet 8.

[0023] The algal biofilm growth vector 2 is a flexible material such as silica gel film, nylon cloth, cotton or linen products, flexible plastic, etc., and a low-speed motor 1 with speed adjustment function is connected to a driving shaft 3 to rotate, and a driven shaft 4 immersed under the liquid surface of a reaction pool 5 to rotate is driven by a power transmission belt 9, so that the loaded algal biofilm growth vector can be rotated alternately in the air-liquid medium according to the power transmission belt 9.

[0024] A number of rotating members arranged parallel to the ground and vertical to the ground and the reaction pool 5 constitute the main body of the algae biofilm module. The fixed frame 6 is used to arrange the low-speed motor 1 and maintain the stability of the overall structure of the compact rotating algae biofilm reactor. The reaction pool 5 is injected with sewage through its bottom water inlet 8, and the treated purified water is discharged through the top outlet 7 on the other side. It should be noted that for display purposes, the distance between the rotating construction modules in Fig. 1-3 is far, and the distance between the adjacent rotating members can be dynamically adjusted according to the actual needs of the application to make full use of the light irradiation after being dispersed by the light guide plate.

[0025] As shown in FIG. 4-6, the light guide module includes a stepping motor 10, a rotatable lens holder 11, a linear Fresnel lens 12, and a light guide plate 13. The linear Fresnel lens 12 is fixed to the rotatable lens holder 11, the base of the rotatable lens holder 11 is in the shape of a character, the light guide plate 13 is installed at the lower end of the base in the shape of a character, and the stepping motor 10 is provided on one side of the linear Fresnel lens 12. The linear Fresnel lens 12 focuses the sunlight into a narrow linear band, and the linear Fresnel lens 12 is driven by the stepping motor 10 to rotate slowly with the change of the angle of the sunlight, so that the sunlight is always focused linearly on one side of the light guide plate 13, forming a surface light source on the light guide plate 13 (the optical path principle is shown in FIG. 7). The light guide plate 13 is fixed in parallel between the adjacent algae biofilm rotating members, providing uniform and stable light irradiation to the algae biofilms on both sides.

[0026] By placing multiple light-guiding modules (the number is the number of rotating members minus 1) in the algal biofilm reactor, the linear Fresnel lens 12 is placed on the top of two adjacent rotating members, and the light-guiding plate 13 is inserted vertically in the middle of the two rotating members and parallel to the surface of the algal biofilm growth vector 2. The stepping motor 10 is placed on the fixed frame 6, and for ease of display, the stepping motor 10 and the low-speed motor 1 in FIG. 10 are arranged on the fixed frame 6 on both sides of the algal biofilm reactor, but in practice, the same-side arrangement or different-side arrangement can be selected according to the size of the stepping motor 10 and the low-speed motor 1 and the size of the arrangement space. In this way, the compact rotating algal biofilm reactor (shown in FIG. 8-10) according to the present invention is formed.

[0027] Example 1 A compact algal biofilm reactor including an algal biofilm module with seven rotating members and six sets of light-guiding modules is constructed in the above-mentioned manner, as shown in Fig. 11-13, one end of the driving shaft 3 is connected to a low-speed motor 1 in the manner of coupling connection, flange connection and coaxial connection, and the other end is connected to a bearing in a fixed frame 6. The low-speed motor 1 is equipped with an electric control module that can adjust the rotation speed of the driving shaft 3, with a rotation speed range of 1 RPM-300 RPM. The driving shaft 3 and the driven shaft 4 are connected to a toothed power transmission belt 9 through gears, the driving shaft 3 is at the top and the driven shaft 4 is at the bottom, and the driving shaft 3 drives the driven shaft 4 to move synchronously through the force transmission action of the power transmission belt 9 during rotation. The flexible algal biofilm growth vector 2 rotates around the driving shaft 3 and the driven shaft 4 in a transmission belt manner. The rotating member and the reaction pool 5 constitute an algae biofilm module, and during actual operation, the bottom of the rotating member is immersed below the liquid level of the reaction pool 5, and both ends of the driven shaft 4 are fixed below the liquid level of the reaction pool 5 via bearings. When the flexible algae biofilm growth vector 2 rotates in the form of a transmission belt, the algae biofilm carried on the flexible algae biofilm growth vector 2 circulates at the air-liquid interface. The drain port 7 is attached to the liquid level of the reaction pool 5, and the water inlet 8 is attached to the bottom of the wall of the reaction pool 5 on the side opposite to the drain port 7. The base of the fixed frame 6 is connected to the reaction pool 5. Two bearing platforms at the upper end of the fixed frame 6 are located on both sides above the reaction pool 5, respectively, and are used to mount the rotating member and the light-guiding module. The stepping motor 10 is connected to one end of the rotation shaft at the bottom of the rotatable lens holder 11, and the other end is connected to a bearing in the "person"-shaped holder base. The stepping motor 10 contains a programmable system for precisely controlling the rotation of the rotatable lens holder 11 so that the plane of the linear Fresnel lens 12 is always kept perpendicular to the incident sunlight. Both sides of the top of the light guide plate 13 are fixed to the fixed frame 6 and hung vertically in the gap between the adjacent algae biofilm rotating members, parallel to the plane of the algae biofilm.The focal point where the linear Fresnel lens 12 concentrates the sunlight is the incident end of the light guide plate 13, and the concentrated incident light is uniformly dispersed by the light guide plate 13 to provide stable light irradiation for the algae biofilms on both sides. In this example, six sets of light guide modules are arranged in the gaps of seven rotating members respectively.

[0028] As a result, the compact rotating algal biofilm reactor described in the present invention can install 2-3 times more rotating members than the conventional rotating algal biofilm reactor with the same site area and vertical height of the algal biofilm, greatly improving the land utilization rate and reactor volume load, and further reducing the cost of treating sewage with the algal biofilm and improving the treatment efficiency.

[0029] Example 2 The algal biofilm reactor described in Example 1 was used to treat sewage, and the steps are as follows:

[0030] 1. Algal biofilm colonies were obtained from the secondary settling pool walls of an actual sewage treatment plant, inoculated into an algal biofilm growth vector 2, and then immersed in synthetic wastewater simulating typical municipal sewage water quality (wastewater COD 180 mg / L, total nitrogen 40 mg / L, total phosphorus 3.5 mg / L).

[0031] The flexible algal biofilm growth vector 2 is mounted on the driving shaft 3 and driven shaft 4 of the rotating member, and the algal biofilm reactor operates in a batch mode, discharging treated water from the drain outlet 7 and injecting freshly prepared synthetic wastewater from the inlet 8 at 6:00 a.m. every day. The corresponding water settling time is 24 h, and the sampling interval is set to 20 d.

[0032] 3. Potassium dichromate method (HJ828-2017), alkaline potassium persulfate UV-Vis-NIR spectroscopy (HJ636-2017), and ammonium molybdate spectrophotometry (GB11893-1989) were used to measure the concentrations of COD, total nitrogen, and total phosphorus in the water samples, respectively. The sample measurement interval was once every two days, and the operation period was one year in total. The results are shown in Figure 14. As can be seen from Figure 14, by using this method to treat typical municipal wastewater, the COD of the wastewater can be stabilized at <30mg / L, the total nitrogen can be stabilized at <2mg / L, and the total phosphorus can be stabilized at <0.5, which meets the limit values ​​of the first-class A standard specified in GB18918-2002, the "Pollutant Discharge Standards for Municipal Sewage Treatment Plants".

[0033] Comparative Example 1 The algae biofilm reactor is compared with Example 1, the only difference is that the light-guiding module in the algae biofilm reactor is removed, and the experimental steps are the same as those in Example 2. Compared with Example 2, the treatment effect of the reactor with the light-guiding module removed and the change in the growth status of the algae biofilm are compared. The growth status of the algae biofilm is expressed in terms of biomass amount per unit area (g VSS / m2) and chlorophyll a content (mg Chla / g VSS). The biomass amount is measured by weighing method, and the chlorophyll a content is measured by absorption photometry. The results are shown in Figure 15. As can be seen from Figure 15, after the light-guiding module is removed in Comparative Example 1, the COD, total nitrogen and total phosphorus concentrations of the reactor wastewater are all increased, but the biomass amount per unit area and chlorophyll a concentration are significantly reduced. According to the above results, after the light-guiding module is removed, the accumulation of the biomass amount of the algae biofilm and the algae growth are suppressed due to uneven light irradiation, and the sewage treatment effect of the reactor is further suppressed. Therefore, the excellent processing effect of the compact reactor can only be achieved by combining the light guide module and the reactor described in the present invention.

Claims

1. 1. A compact rotating algal biofilm reactor comprising: The algae biofilm module and the light guide module are fitted together, The algal biofilm module includes a plurality of rotating members and a reaction pool (5), a fixed frame (6) is provided on the upper part of the reaction pool (5), the rotating members include a low-speed motor (1), an algal biofilm growth vector (2) and a power transmission belt (9), the low-speed motor (1) is fixed on the upper part of the fixed frame (6), a drive shaft (3) is connected to one side of the low-speed motor (1), a driven shaft (4) is provided below the liquid level in the reaction pool (5), the algal biofilm growth vector (2) is connected to the ... a light guide module (11) including a light guide plate (13) and a linear Fresnel lens (12) fixedly mounted on an upper end of the rotatable lens holder (11); a light guide plate (13) mounted on a lower end of the rotatable lens holder (11); a stepping motor (10) mounted on one side of the linear Fresnel lens (12); and the stepping motor (10) mounted on the fixed frame (6).

2. 2. The compact rotating algal biofilm reactor of claim 1, wherein the number of rotating members is two or more.

3. The compact rotating algae biofilm reactor of claim 2, characterized in that the linear Fresnel lens (12) can be moved by the stepping motor (10) to rotate slowly with the change of the sunlight angle, and always focuses the sunlight linearly on one side of the light guide plate (13) to form a surface light source on the light guide plate (13), and the light guide plate (13) is fixed in parallel between adjacent rotating members.

4. 4. The compact rotating algal biofilm reactor according to claim 3, characterized in that the linear Fresnel lenses (12) are provided on the tops of two adjacent rotating members, and the light guide plate (13) is inserted vertically in the middle of the adjacent rotating members and parallel to the surface of the algal biofilm growth vector (2).

5. 2. The compact rotating algal biofilm reactor according to claim 1, characterized in that the base of the rotatable lens holder (11) is in the shape of a human.

6. 2. A compact rotating algal biofilm reactor according to claim 1, characterized in that the algal biofilm growth vector (2) is a flexible material.

7. 7. The compact rotating algal biofilm reactor of claim 6, wherein the flexible material is silica gel film, nylon cloth, cotton or linen products or flexible plastic.

8. The compact rotating algal biofilm reactor of claim 1, characterized in that the low-speed motor (1) is connected to and rotates with the driving shaft (3), and the power transmission belt (9) drives and rotates the driven shaft (4) that is immersed under the liquid surface of the reaction pool (5), so that the algal biofilm growth vector (2) can be alternately rotated in the gas-liquid medium following the power transmission belt (9).

9. The compact rotating algal biofilm reactor according to claim 1, characterized in that the stepping motor (10) and the low-speed motor (1) may be arranged on the same side of the fixed frame (6) or on different sides.

10. The compact rotating algal biofilm reactor according to any one of claims 1 to 9, characterized in that a water inlet (8) is provided at the bottom of one side of the reaction pool (5), and a drain (7) is provided on the other side opposite the water inlet (8).

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