Treatment system for producing biomass energy by utilizing antibiotic-containing high-concentration wastewater

Abstract

The utility model discloses a treatment system for producing biomass energy by utilizing antibiotic-containing high-concentration wastewater. The system consists of a wastewater pretreatment unit, a struvite precipitation treatment unit, a microalgae resourceful treatment wastewater unit, a biomass efficient flocculation and recovery unit, a wastewater circulation treatment unit and a biodiesel extraction production unit which are sequentially connected together through pipelines. According to the utility model, high-concentration wastewater can be treated by coupling a struvite precipitation method and a microalgae wastewater treatment method, so that the water quality is purified; and antibiotics in the wastewater can be effectively biodegraded, and fertilizers and microalgae biodiesel can be produced, so that the implementation cost is greatly reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of wastewater treatment, and particularly relates to a treatment system for producing biomass energy by utilizing high-concentration wastewater containing antibiotics. Background Art

[0002] Antibiotics are widely used in human disease treatment and animal husbandry because of their broad-spectrum antibacterial effects. The abuse of a large number of antibiotics has led to increasingly serious environmental pollution. Antibiotics can be detected in rivers, soil, groundwater and other places. Antibiotics widely present in wastewater have a great impact on the ecological environment.

[0003] There are mainly physical, chemical and biological methods for degrading antibiotics in wastewater. Physical methods mainly rely on physical adsorption and neutralization of charged ions; chemical methods mainly rely on interactions between functional groups and complex reactions. The disadvantages of physical methods are that they will produce secondary pollution and that adsorption is selective; the disadvantages of chemical methods are that they are expensive and will produce intermediate toxic products. Traditional wastewater treatment technologies are difficult to effectively degrade antibiotics, and microalgae resource-based wastewater treatment technology has broad prospects in this field.

[0004] The resource-based treatment of wastewater by microalgae biotechnology utilizes the metabolism and adsorption of microalgae itself to remove nutrients from wastewater. At the same time, photosynthesis and bio-enzyme reactions are used to achieve good degradation of antibiotics. A large number of current studies have shown that microalgae are not very effective in purifying water quality and degrading antibiotics in high-concentration wastewater. A feasible solution to this problem is to convert high-concentration wastewater into low-concentration wastewater so that microalgae can grow better. Struvite (MAP), with the molecular formula MgNH4PO4·6H2O, is a white crystal that is insoluble in water. The struvite precipitation method in wastewater treatment, also known as magnesium ammonium phosphate precipitation, is a method of adding magnesium ions to wastewater containing phosphate and ammonia nitrogen to react to form insoluble struvite precipitates to achieve denitrification and phosphorus removal from wastewater. The use of this method to convert high-concentration wastewater into low-concentration wastewater provides a good prerequisite for subsequent microalgae resource treatment of wastewater. Utility Model Content

[0005] The purpose of the utility model is to provide a treatment system for producing biomass energy by utilizing high-concentration wastewater containing antibiotics. The system couples the wastewater treatment with microalgae resource treatment by using a struvite precipitation method, thereby simply and efficiently solving the pollution problem of treating high-concentration wastewater containing antibiotics. The treatment system will not cause secondary pollution, and the energy value of microalgae can also be utilized, thereby significantly reducing the economic cost of the wastewater resource treatment system.

[0006] In order to achieve the above-mentioned effects, the specific technical solution adopted by the utility model is: a treatment system for producing biomass energy using high-concentration wastewater containing antibiotics, the system is composed of a wastewater pretreatment unit, a struvite precipitation treatment unit, a microalgae resource treatment wastewater unit, a biomass efficient flocculation and harvesting unit, a wastewater circulation treatment unit and a biodiesel extraction and production unit which are connected in sequence through pipelines.

[0007] Furthermore, the wastewater pretreatment unit includes a grid and a regulating tank which are sequentially connected together through pipelines.

[0008] Furthermore, the struvite precipitation treatment unit includes a batching tank and a struvite crystallization precipitation tank which are sequentially connected together through pipelines.

[0009] Furthermore, the microalgae resource utilization wastewater treatment unit includes a pH adjustment tank and a photobioreactor which are sequentially connected together through pipelines.

[0010] Furthermore, the regulating tank, the struvite crystallization sedimentation tank and the pH regulating tank are all equipped with a pH intelligent measuring instrument.

[0011] Furthermore, the biomass efficient flocculation and harvesting unit comprises a flocculation and sedimentation tank, and the flocculation and sedimentation tank is provided with two discharge ports, one of which is connected to the filtrate tank, and the other is connected to the biodiesel extraction and production unit.

[0012] Furthermore, the wastewater circulation treatment unit includes a filtrate pool and a photobioreactor. The filtrate pool is provided with two outlets, one outlet is connected to the photobioreactor, and the other outlet is connected to the water storage pool. An antibiotic detector and a water quality analyzer are installed in the filtrate pool.

[0013] Furthermore, the biodiesel extraction production unit includes a low-temperature dryer, a microalgae oil extraction reactor and an ester exchange reactor which are sequentially connected through pipelines.

[0014] Furthermore, an agitator is installed in the struvite crystallization sedimentation tank.

[0015] Furthermore, an aeration device is installed in the photobioreactor.

[0016] Due to the adoption of the above technical solution, the beneficial effects of the utility model are as follows:

[0017] 1. The utility model utilizes the struvite precipitation method coupled with microalgae biotechnology to treat high-concentration wastewater containing antibiotics. The high-concentration wastewater is converted into low-concentration wastewater through the struvite precipitation method, thereby promoting the growth of microalgae and enhancing the performance of microalgae in degrading antibiotics.

[0018] 2. The utility model produces fertilizer and biodiesel while treating wastewater containing antibiotics, which solves part of the energy supply problem to a certain extent and generates certain economic benefits.

[0019] 3. The utility model uses a photobioreactor. Compared with the traditional raceway pool for cultivating microalgae, the photobioreactor has a more efficient ability to cultivate microalgae, which can enable the microalgae to purify wastewater quality and degrade antibiotics more efficiently.

[0020] 4. The utility model uses a struvite crystallization sedimentation tank to convert high-concentration wastewater into low-concentration wastewater, thereby improving the adaptability and growth performance of microalgae in wastewater.

[0021] 5. The utility model has many advantages such as simple operation, low construction cost, low operating cost, etc. It is a continuous wastewater treatment system with green environmental protection and sustainable development advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a connection structure block diagram of the utility model;

[0023] As shown in the figure: 1-grid; 2-regulating tank; 3-batch tank; 4-struvite crystallization sedimentation tank; 5-pH regulating tank; 6-photobioreactor; 7-flocculation sedimentation tank; 8-filtrate tank; 9-water storage tank; 10-low temperature dryer; 11-microalgae oil extraction reactor; 12-ester exchange reactor. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the utility model clearer, the utility model is further described in detail below with reference to the accompanying drawings and embodiments.

[0025] Example

[0026] See also Figure 1 In this embodiment, a treatment system for producing biomass energy using high-concentration wastewater containing antibiotics is provided. The system is composed of a wastewater pretreatment unit, a struvite precipitation treatment unit, a microalgae resource treatment wastewater unit, a biomass efficient flocculation and harvesting unit, a wastewater circulation treatment unit, and a biodiesel extraction and production unit, which are connected in sequence through pipelines.

[0027] The wastewater pretreatment unit comprises a grid 1 and a regulating tank 2 which are sequentially connected together through pipelines. The grid 1 removes the residue in the wastewater, and the regulating tank 2 preliminarily adjusts the pH of the wastewater.

[0028] The struvite precipitation treatment unit comprises a batching tank 3 and a struvite crystallization precipitation tank 4 which are sequentially connected together through pipelines.

[0029] The microalgae resource treatment wastewater unit comprises a pH adjustment tank 5 and a photobioreactor 6 which are sequentially connected by pipelines. The pH adjustment tank 5 is used to adjust the pH of the wastewater to match the natural growth environment of the microalgae, and the photobioreactor 6 is used to facilitate the photosynthesis of the microalgae by natural light, so that the microalgae can purify the wastewater and degrade the antibiotics through its own metabolism and adsorption.

[0030] The regulating tank 2, the struvite crystallization sedimentation tank 4 and the pH regulating tank 5 are all equipped with pH intelligent measuring instruments to facilitate the adjustment of the pH of the wastewater.

[0031] The biomass efficient flocculation and harvesting unit comprises a flocculation sedimentation tank 7, wherein the flocculation sedimentation tank 7 is provided with two discharge ports, one of which is connected to the filtrate tank 8, and the other is connected to the biodiesel extraction production unit. In the flocculation sedimentation tank 7, a high-efficiency flocculant is used to separate microalgae and purified wastewater.

[0032] The wastewater circulation treatment unit comprises a filtrate pool 8 and a photobioreactor 6 . The filtrate pool 8 is provided with two discharge ports, one of which is connected to the photobioreactor 6 , and the other is connected to the water storage pool 9 .

[0033] The biodiesel extraction production unit comprises a low temperature dryer 10, a microalgae oil extraction reactor 11 and an ester exchange reactor 12 which are sequentially connected by pipelines. The low temperature dryer 10 prepares dry microalgae biomass through oil extraction, and the microalgae biomass is made into biodiesel after ester exchange reaction.

[0034] The struvite crystallization sedimentation tank 4 is provided with an agitator to improve the reaction effect.

[0035] The photobioreactor 6 is equipped with an aeration device to allow the wastewater in the photobioreactor 6 to fully contact with the microalgae, thereby ensuring that the microalgae in the reactor degrade the antibiotics in the wastewater under the condition of sufficient dissolved oxygen.

[0036] The utility model is a working process comprising the following steps:

[0037] Step 1: discharge the wastewater containing antibiotics into the screen 1. The screen 1 intercepts the floating objects and larger suspended solids in the wastewater to prevent blockage and entanglement of the water pump unit, aerator, pipeline valve, water distribution facilities of the treatment structure, and water inlets and outlets, reduce the scum generated by subsequent treatment, and ensure the normal operation of each unit facility of the wastewater treatment.

[0038] Step 2: The treated wastewater is discharged into the regulating tank 2 through a pipeline to adjust the water volume and balance the water quality. The specific functions include: providing buffering capacity for organic loads to prevent drastic changes in the biological treatment system. Controlling the pH value to reduce the amount of chemicals used in the neutralization process, while controlling the pH to be acidic to prevent struvite precipitation in the batching tank 3. When the factory stops production, wastewater can still be input into the biological treatment system. Controlling the discharge of wastewater to the municipal system to alleviate changes in the wastewater load distribution and prevent high concentrations of toxic substances from entering the biological treatment system.

[0039] Step 3: The wastewater from the wastewater pretreatment unit is discharged into the batching tank 3 through a pipeline. The batching tank is equipped with an intelligent NH4 + PO4 3- Analyzer, analyzes NH4 + PO4 3- The content of Mg 2+ :NH4 + :PO4 3- =1:1:1, calculate the mass of magnesium chloride solid to be added. An intelligent magnesium chloride dosing machine is installed on the batching tank 3, and an appropriate amount of magnesium chloride solid is added according to the calculation.

[0040] Step 4, the treated wastewater prepared in the batching tank 3 is transported to the struvite crystallization sedimentation tank 4 through a pipeline. There is a pH intelligent measuring instrument on the struvite crystallization sedimentation tank 4 for real-time detection of pH to calculate the dosage of the pH regulator. The pH of the struvite crystallization sedimentation tank is controlled between 8.5 and 9.5. When the environmental pH is between 8.5 and 9.5, the struvite shows a negative potential, and the antibiotic shows a negative potential. The two show a repulsive force, which prevents the antibiotic from migrating to the struvite to the maximum extent. An agitator is installed in the struvite crystallization sedimentation tank 4 to promote the reaction and the crystallization and precipitation of struvite. When the precipitation is complete, the struvite can be taken out and then sent to a fertilizer processing plant to be made into fertilizer. At this time, the high-concentration wastewater is treated to become low-concentration wastewater, which can be suitable for the normal growth of microalgae.

[0041] Step 5: Use a pipeline to transport the low-concentration wastewater treated in the struvite crystallization sedimentation tank 4 to the pH adjustment tank 5, and add HCl solution to adjust the pH in the adjustment tank to a range suitable for the growth of microalgae, generally 7.1±0.2.

[0042] Step 6: The treated wastewater in the pH regulating tank 5 is transported to the photobioreactor 6 by an ascending water pump, and a microalgae culture solution is added to the photobioreactor 6. Microalgae perform photosynthesis through illumination, and purify water and degrade antibiotics through their own metabolism, growth and reproduction, and adsorption. In this embodiment, it is recommended to use Chlorella sorokiniana, which has a good effect in biodegrading antibiotics (for example, a large number of documents show that the removal rate of tetracycline by Chlorella sorokiniana is more than 95%, and the removal rate of ciprofloxacin is more than 80%). At the same time, the stress of antibiotics can greatly increase the oil content of the chlorella, greatly increasing the yield of biodiesel.

[0043] Step seven, transport the algae liquid formed by the microalgae wastewater culture in the photobioreactor 6 to the flocculation sedimentation tank 7 through a pipeline, add a high-efficiency flocculant thereto, and separate the microalgae from the purified wastewater. In order to prevent the system from generating secondary pollution, it is recommended to use chitosan flocculant. Chitosan is a natural polymer material with low cost, wide source, simple structure and biodegradability, and has both flocculation and bactericidal properties. Chitosan exhibits both high efficiency and environmental friendliness in the flocculation process. The flocculation sedimentation tank 7 is provided with two discharge ports, one of which is connected to the filtrate tank 8, and the other is connected to the low-temperature dryer 10.

[0044] Step eight, two discharge ports are set in the filtrate pool 8, and both discharge ports are equipped with one-way valves. One of the discharge ports is connected to the photobioreactor 6, and the other is connected to the water storage pool 9. An antibiotic detector and a water quality analyzer are installed in the filtrate pool 8 to analyze the real-time concentration of antibiotics and water quality to see whether they meet the national standards (or are measured by artificial instruments). If the national standards are met, the filtrate is transported to the water storage pool 9; if the national standards are not met, the filtrate is transported to the photobioreactor 6 for secondary microalgae resource wastewater treatment (adding new microalgae culture concentrate). The wastewater that has been tested and meets the national emission standards will be discharged into the water storage pool 9. The water storage pool 9 is also equipped with two discharge ports, one is connected to the pH adjustment tank, and the other is connected to the urban green plant irrigation system of the municipal system to alleviate the city's water pressure. (Note that the valve of the discharge port of the regulating tank 5 needs to be closed when performing the secondary resource wastewater treatment step.)

[0045] Step nine, the feed port of the low-temperature dryer 10 in the biodiesel extraction production unit is connected to the flocculation sedimentation tank 7, and the discharge port is connected to the microalgae oil extraction reactor 11. The low-temperature dryer 10 adopts a low-temperature drying process. Low-temperature drying is a special process that evaporates water from the microalgae mud at a relatively low temperature. In this way, thermal damage to the microalgae caused by high temperature can be avoided, thereby maintaining a high oil content in the microalgae and reducing the oil loss of the microalgae. The temperature of low-temperature drying is usually between 40 and 80°C, and air flow or vacuum drying is usually used to accelerate the evaporation rate of water.

[0046] Step 10, microalgae oil extraction reactor 11 includes breaking the microalgae and extracting oil from the broken microalgae using an organic solvent. A discharge port is provided to connect with the transesterification reactor 12. Transesterification is the most commonly used method for preparing microalgae biodiesel, and this technology should be relatively mature on a large scale. The transesterification reactor 12 is provided with a discharge port, and the preparation of microalgae biodiesel in this step will significantly reduce the economic cost of this embodiment.

[0047] Through the above embodiments, the experimental new type can not only use the struvite precipitation method coupled with the microalgae wastewater treatment method to treat high-concentration wastewater, thereby purifying the water quality; it can also effectively biodegrade the antibiotics in the wastewater, and can also produce fertilizers and microalgae biodiesel, greatly reducing the implementation cost. The utility model not only proposes an innovative treatment method for environmental sewage treatment at this stage, but also makes certain contributions to national agricultural production and energy issues. The wastewater treatment and energy production process proposed by the utility model is uncomplicated, simple in steps, highly stable and green and environmentally friendly, which is conducive to the development of the national environmental cause and energy production field.

Claims

1. A treatment system for producing biomass energy using high-concentration wastewater containing antibiotics, characterized in that: The system consists of a wastewater pretreatment unit, a struvite precipitation treatment unit, a microalgae resource treatment wastewater unit, a biomass efficient flocculation and harvesting unit, a wastewater circulation treatment unit and a biodiesel extraction and production unit which are connected in sequence through pipelines.

2. The processing system for producing biomass energy using high-concentration wastewater containing antibiotics according to claim 1, characterized in that: The wastewater pretreatment unit comprises a grid (1) and a regulating tank (2) which are sequentially connected together through pipelines.

3. The processing system for producing biomass energy using high-concentration wastewater containing antibiotics according to claim 1, characterized in that: The struvite precipitation treatment unit comprises a batching tank (3) and a struvite crystallization precipitation tank (4) which are sequentially connected together through pipelines.

4. The processing system for producing biomass energy using high-concentration wastewater containing antibiotics according to claim 1, characterized in that: The microalgae resource utilization wastewater treatment unit comprises a pH adjustment tank (5) and a photobioreactor (6) which are sequentially connected together through pipelines.

5. The processing system for producing biomass energy using high-concentration wastewater containing antibiotics according to claim 2, characterized in that: The regulating tank (2), the struvite crystallization sedimentation tank (4), and the pH regulating tank (5) are all equipped with a pH intelligent measuring instrument.

6. The processing system for producing biomass energy using high-concentration wastewater containing antibiotics according to claim 1, characterized in that: The biomass efficient flocculation and harvesting unit comprises a flocculation and sedimentation tank (7), wherein the flocculation and sedimentation tank (7) is provided with two discharge ports, one of which is connected to a filtrate tank (8), and the other is connected to a biodiesel extraction and production unit.

7. The processing system for producing biomass energy using high-concentration wastewater containing antibiotics according to claim 1, characterized in that: The wastewater circulation treatment unit comprises a filtrate pool (8) and a photobioreactor (6); the filtrate pool (8) is provided with two discharge ports, one of which is connected to the photobioreactor (6) and the other of which is connected to a water storage pool (9); an antibiotic detector and a water quality analyzer are installed in the filtrate pool (8).

8. The processing system for producing biomass energy using high-concentration wastewater containing antibiotics according to claim 1, characterized in that: The biodiesel extraction production unit comprises a low-temperature dryer (10), a microalgae oil extraction reactor (11) and an ester exchange reactor (12) which are sequentially connected via pipelines.

9. The processing system for producing biomass energy using high-concentration wastewater containing antibiotics according to claim 3, characterized in that: A stirrer is installed in the struvite crystallization sedimentation tank (4).

10. The processing system for producing biomass energy by utilizing high-concentration wastewater containing antibiotics according to claim 7, characterized in that: An aeration device is installed in the photobioreactor (6).

Images