A low-carbon in-situ sludge reduction sewage treatment device

Abstract

The present invention discloses a low-carbon, in-situ sludge-reduction sewage treatment device, comprising the following components: a biological reaction unit, a filler rack assembly, an aeration device, an online monitoring device, and a flocculation and sedimentation device. Leveraging the advantages of biological contact oxidation technology—high volumetric load, long biofilm sludge age, and simple operation—the device combines a novel device structure with efficient contact oxidation fillers and a preferred nitrification liquid recirculation tank. Ultimately, the device achieves sludge reduction while ensuring effluent water quality meets design requirements.

Description

Technical Field

[0001] The present invention belongs to the fields of sewage treatment, sludge reduction and biological contact oxidation, and particularly relates to a low-carbon in-situ sludge reduction sewage treatment device. Background Art

[0002] The biological treatment process of domestic sewage or industrial organic wastewater is equivalent to a small, artificially constructed ecosystem. In addition to microorganisms such as bacteria, many microorganisms are also present in activated sludge, such as protozoa and metazoans. Protozoa and metazoans are at the top of the food chain in this ecosystem and survive by ingesting tiny organisms, mainly bacteria. Energy is transferred from the bottom of the food chain. The longer the ecosystem food chain, the greater the energy loss, and thus the less sludge is produced. Therefore, the purpose of sludge reduction can be achieved through this principle. The micro-animal predation sludge reduction process not only has low operating costs and low energy consumption, but also produces almost no by-products and no secondary pollution. Therefore, this process is a typical representative of green sludge reduction technology.

[0003] The biological contact oxidation process, also known as the "submerged biofilter," "contact aeration method," or "fixed activated sludge process," involves filling a biological reactor with filler material. Aerated wastewater then flows through the filler material at a constant velocity. This filler material forms a biofilm, creating extensive contact between the wastewater and the biofilm. The metabolic activity of the microorganisms within the biofilm removes organic pollutants and purifies the wastewater. The inclusion of filler material within the biological tank of the biological contact oxidation process allows for a high volumetric load, long biofilm sludge life, and simple operation.

[0004] The process based on contact oxidation generally adopts one to three-stage treatment. The water quality gradient from the first to the last stage is not obvious. The types of microorganisms attached to the fillers at each level are relatively similar. There is no obvious stratification of the microbial food chain between the levels, resulting in a large amount of residual sludge. At the same time, the effluent water quality does not further decline. In addition, the traditional hanging filler process based on contact oxygen, such as three-dimensional elastic filler, composite filler, etc., has the main disadvantage of small specific surface area, which generally does not exceed 500m 2 / m 3 The biomass per unit volume of the biochemical pool is small. To achieve a good ecosystem food chain, a larger volume is required, resulting in an increase in overall investment. In addition, this type of filler is prone to aging and has a service life of 3-5 years. The material replacement rate is high, resulting in unnecessary secondary investment and maintenance. Another type of MBBR (Moving Bed Biofilm Reactor) process, which mainly uses contact oxygen, generally has a specific surface area of no more than 1000m 2 / m 3The problem of low biofilm formation also exists. Improper MBBR process design or use can lead to problems such as suboptimal fluidization of the MBBR filler, localized accumulation, blockage of the interception net, wear of the agitator, wear of the filler itself, and the need for regular replenishment. Furthermore, traditional processes based on contact oxidation, due to their limited number of treatment unit stages, are unable to precisely control the dissolved oxygen content in the water according to actual sewage treatment requirements, resulting in extensive aeration control and high energy consumption.

[0005] The present invention has been proposed to solve the above-mentioned problems. Summary of the Invention

[0006] The present invention discloses a low-carbon in-situ sludge reduction sewage treatment device. The device of the present invention not only achieves the final effluent water quality meeting the design requirements, but also achieves the purpose of sludge reduction; the degree of organic sludge reduction can reach 50-95%.

[0007] The technical solutions of the present invention are as follows:

[0008] A low-carbon in-situ sludge reduction sewage treatment device, characterized by comprising the following parts: a biological reaction unit, a filler rack device, an aeration device, an online monitoring device, and a flocculation sedimentation device;

[0009] The biological reaction unit comprises 3-30 rectangular biological reaction tanks, each of which has a common wall. A plurality of water distribution holes 6 are evenly arranged at 1 / 10-1 / 5 of the bottom of the common wall between the odd-numbered biological reaction tanks 1A, 2A, 3A, 4A... and the even-numbered biological reaction tanks 1B, 2B, 3B, 4B...; a plurality of triangular overflow troughs 7 are evenly arranged at 1 / 20-1 / 10 of the top of the common wall between the even-numbered biological reaction tanks 1B, 2B, 3B, 4B... and the odd-numbered biological reaction tanks 1A, 2A, 3A, 4A...; the water distribution holes 6 are generally gaps at the bottom of the common wall, the height of the gaps being 1 / 10-1 / 5 of the height of the common wall; the function of the biological reaction unit is to provide space and a certain reaction time for microbial water purification and sludge reduction; the water flow pattern of the biological reaction unit provides the optimal water inlet pattern for the biological reaction tank, reduces short-circuiting in the biological reaction tank, and improves the reaction efficiency of the biological reaction tank;

[0010] A packing rack device, comprising a packing rack 16 and packing 17 on the packing rack; the packing rack device is evenly arranged in each bioreactor, and the packing rack plane is a series of standardized modules of 1×1m, 1×2m, 2×2, 2×3m or 3×3m; the packing rack 16 is made of carbon steel, stainless steel or engineering plastic structure;

[0011] The aeration device includes an aerator 4, an aeration branch pipe 3, and an aeration pipe valve 5. The aerator 4 is arranged at the bottom of each bioreactor, connected to the aeration branch pipe 3, and the aeration pipe valve 5 is on the aeration branch pipe 3. The aerator 4 can be a disc-type microporous aerator, a tubular microporous aerator, or other types of aerators. The aeration branch pipe 3 can be composed of a carbon steel pipe, a stainless steel pipe, or a plastic pipe. The aeration branch pipe regulating valve 5 can be a pneumatic regulating valve, an electric regulating valve, etc. Depending on the process requirements, some bioreactors may not be equipped with an aeration device. The function of the aeration device is to provide the necessary oxygen for aerobic microorganisms.

[0012] Online monitoring device: including ORP online meter, pH online meter and DO online meter; online monitoring device provides the best reaction conditions for the growth of microorganisms;

[0013] Flocculation and sedimentation device: arranged at the subsequent end of the biological reaction unit, the flocculation and sedimentation device includes a plurality of flocculation and sedimentation tanks 22; the function of the flocculation and sedimentation device is to remove the suspended solids (SS) generated in the biological reaction tank, and at the same time reduce the phosphorus content in the water by adding drugs, so that the effluent can meet the requirements of the unit effluent or the final effluent.

[0014] Preferably, several of the biological reaction tanks are selected as nitrification liquid reflux tanks; the nitrification liquid reflux tanks are connected to the front-end biological reaction tank 1A through a nitrification liquid reflux pipe; one of the nitrification liquid reflux tanks is the rear-end biological reaction tank; the function of the nitrification liquid reflux device is to reflux the nitrification liquid to the front-end, and realize denitrification removal of total nitrogen in the front-end biological reaction tank.

[0015] Preferably, there are two nitrification liquid return pools, and the method of selecting the biological reaction pool as the nitrification liquid return pool is:

[0016] When the total number of biological reaction tanks is 3-5, the first to last and the second to last biological reaction tanks are selected as nitrification liquid return tanks; when the total number of biological reaction tanks is 6-9, the first to last and the third to last biological reaction tanks are selected as nitrification liquid return tanks; when the total number of biological reaction tanks is 10-15, the first to last and the fourth to last biological reaction tanks are selected as nitrification liquid return tanks; when the total number of biological reaction tanks is 16-30, the first to last and the fifth to last biological reaction tanks are selected as nitrification liquid return tanks.

[0017] Preferably, there are 14 bioreactors with the same size and shape; the aspect ratio of the bioreactors is ≥1, and the depth of the bioreactors is between 1.5-10 m.

[0018] Preferably, the filler 17 is in the form of a cloth woven from fibers and fixed to the filler frame 16 along its edge; the specific surface area of the filler 17 is ≥ 20,000 m 2 / kg. The filler fiber is a new polymer material with a hydrophilic surface modification. This fiber filler is carefully selected from materials outside the industry and has been repeatedly proven to be effective and has a guaranteed service life of over 10 years. The fiber filler and filler frame function as a carrier for microbial attachment, providing the necessary contact area for sufficient reaction between microorganisms and pollutants.

[0019] Preferably, there are two nitrification liquid reflux pools, namely: a first nitrification liquid reflux pool 6A and a second nitrification liquid reflux pool 7B; wherein the first nitrification liquid reflux pool 6A is connected to the front-end biological reaction pool 1A through a first nitrification liquid reflux pipe 8; wherein the second nitrification liquid reflux pool 7B is connected to the front-end biological reaction pool 1A through a second nitrification liquid reflux pipe 12; the first nitrification liquid reflux pipe 8 is provided with a first nitrification liquid reflux pump 9 and a first nitrification liquid flowmeter 11; the second nitrification liquid reflux pipe 12 is provided with a second nitrification liquid reflux pump 13 and a second nitrification liquid flowmeter 15.

[0020] Preferably, an ORP online meter 19 and a first pH online meter 18 are provided in the front-end bioreactor 1A; and a DO online meter 21 and a second pH online meter 20 are provided in the rear-end bioreactor 7B.

[0021] The direction of water flow Figure 1 As shown, finally, qualified water quality is obtained from the effluent of the flocculation sedimentation device; and the remaining sludge is discharged from the flocculation sedimentation tank 22.

[0022] Beneficial effects of the present invention:

[0023] 1. There are different standards for sewage discharge, including national standards, local standards or industry standards; sewage treatment plants must implement different emission standards according to their location or industry. National standards include "GB18918-2002 Urban Sewage Treatment Plant Emission Standards", and local standards include Beijing Local Standard "DB11 / 307-2013 Water Pollutant Comprehensive Emission Standards"; all mandatory water quality indicators in the standards must be met. There is no national standard for sludge reduction, and the final disposal costs of sludge in different places are different. The high disposal costs have given rise to the demand for sludge reduction. The device of the present invention utilizes the advantages of biological contact oxidation technology, such as high volumetric load, long biofilm sludge age, and simple operation, combined with a novel equipment structure, efficient contact oxidation fillers, and a preferred nitrification liquid recirculation tank, to achieve the purpose of sludge reduction while ultimately achieving the water quality of the effluent meeting the design requirements; the degree of reduction of organic sludge can reach 50-95%.

[0024] 2. Due to regional differences, the land used for sludge disposal and the cost of treatment vary greatly, and the importance of sludge reduction varies greatly in different regions. However, influenced by existing specifications and traditional designs, and without regulatory requirements for sludge reduction, actual engineering designs are more concerned with the cost and energy consumption of sewage treatment, and rarely consider the increasingly urgent requirements for sludge disposal. The low-carbon in-situ sludge reduction sewage treatment device of the present invention increases the number of biological reaction tanks, optimizes the water distribution and water outlet methods of the biological reaction units, and effectively solves the problem of water short-circuiting. Different biological reaction tanks have different requirements for oxygen. The present invention can achieve precise control of different biological reaction tanks according to oxygen demand to reduce energy consumption. Compared with traditional methods, the sewage treatment device of the present invention can reduce energy consumption by 15-25%.

[0025] 3. Domestic sewage contains organic nitrogen and ammonia nitrogen. These nitrogen and nitrates must be converted into nitrates by aerobic microorganisms. Under the influence of oxygen deprivation, nitrates are denitrified and converted into nitrogen gas for excretion, thereby reducing the total nitrogen in the water and meeting wastewater standards. Aerobic bioreactors progressively degrade organic nitrogen and ammonia nitrogen from the front to the back end of the water, resulting in lower organic nitrogen and ammonia nitrogen levels towards the back end, while the dissolved oxygen level increases. Since denitrification requires low dissolved oxygen (DO < 0.5 mg / l) for efficient operation, improper control can easily lead to excessively high dissolved oxygen levels in the denitrification zone when the nitrification solution is returned from the final bioreactor, compromising denitrification efficiency. Returning the nitrification solution from the intermediate bioreactors maintains low dissolved oxygen levels, minimizing the impact on denitrification and improving denitrification efficiency. However, this intermediate zone may experience incomplete degradation of organic nitrogen and ammonia nitrogen, resulting in low levels of nitrate converted to nitrate, leading to low denitrification efficiency. The present invention provides a dual reflux system for nitrification liquid. Based on the nitrification reaction conditions and dissolved oxygen content in the actual project, the bioreactor tank can be flexibly selected as the nitrification liquid reflux tank. The nitrification liquid reflux rate can also be adjusted at different bioreactor stages to maximize denitrification efficiency. Generally, the nitrification liquid reflux rate is 1-5 times the device's influent volume. The amount of refluxed nitrification liquid is determined primarily based on the nitrification liquid content in the water and the required effluent water quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the low-carbon in-situ sludge reduction sewage treatment device of the present invention.

[0027] The accompanying drawings are marked as follows: 1A, 2A, 3A, 4A..., odd-numbered biological reaction tanks; 1B, 2B, 3B, 4B..., even-numbered biological reaction tanks; 3, aeration branch pipe; 4, aerator; 5, aeration pipe valve; 6, water distribution hole; 7, triangular overflow trough; 8, first nitrification liquid reflux pipe; 9, first nitrification liquid reflux pump; 10, first nitrification liquid reflux valve; 6A, first nitrification liquid reflux tank; 11, first nitrification liquid flowmeter; 12, second nitrification liquid reflux pipe; 13, second nitrification liquid reflux pump; 14, second nitrification liquid reflux valve; 7B, second nitrification liquid reflux tank; 15, second nitrification liquid flowmeter; 16, packing rack; 17, packing; 18, first pH value online meter; 19, ORP value online meter; 20, second pH value online meter; 21, DO value online meter; 22, flocculation sedimentation tank. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0029] like Figure 1As shown, a low-carbon in-situ sludge reduction sewage treatment device of the present invention includes the following parts: a biological reaction unit, a filler rack device, an aeration device, a nitrification liquid reflux device, an online monitoring device, and a flocculation sedimentation device; wherein the biological reaction unit is 3-30 rectangular biological reaction tanks, and the biological reaction tanks share a common wall; wherein the odd-numbered biological reaction tanks 1A, 2A, 3A, 4A... and the even-numbered biological reaction tanks 1B, 2B, 3B, 4B... are connected along the bottom of the common wall. Multiple water distribution holes 6 are evenly arranged at 1 / 10-1 / 5; multiple triangular overflow grooves 7 are evenly arranged at 1 / 20-1 / 10 of the upper end of the common wall of the even-numbered biological reaction tanks 1B, 2B, 3B, 4B... and the odd-numbered biological reaction tanks 1A, 2A, 3A, 4A...; the water distribution holes 6 are generally gaps at the bottom of the common wall, and the height of the gaps is 1 / 10-1 / 5 of the common wall height; the function of the biological reaction unit is to provide space for microbial water purification and sludge reduction and a certain reaction time; the water flow mode of the biological reaction unit provides the optimal water inlet mode for the biological reaction tank, reduces the short-circuit phenomenon of the biological reaction tank, and improves the reaction efficiency of the biological reaction tank; wherein, the packing rack device includes a packing rack 16 and a packing 17 on the packing rack; the packing rack device is evenly arranged in each biological reaction tank of the biological reaction unit, and the packing rack plane is a 1×1m, 1×2m, 2×2, 2×3m or 3×3m series standardized module; the packing rack 16 is a carbon steel, stainless steel or engineering plastic structure; wherein, the aeration device includes an aerator 4, an aeration branch pipe 3 and an aeration pipe valve 5; the aerator 4 is arranged at the bottom of each biological reaction tank, the aerator 4 is connected to the aeration branch pipe 3, and the aeration pipe valve 5 is on the aeration branch pipe 3; the aerator 4 can be a disc microporous aerator, a tubular microporous aerator, or other types of aerators; the aeration branch pipe 3 can be composed of a carbon steel pipe, a stainless steel pipe, or a plastic pipe; the aeration branch pipe regulating valve 5 can be a pneumatic regulating valve, an electric regulating valve, etc.According to the process requirements, some biological reaction tanks may not be equipped with aeration devices; the function of the aeration device is to provide the necessary oxygen for aerobic microorganisms; several of the biological reaction tanks are selected as nitrification liquid return tanks; the nitrification liquid return tank is connected to the front-end biological reaction tank 1A through a nitrification liquid return pipe; one of the nitrification liquid return tanks is the rear-end biological reaction tank; the function of the nitrification liquid return device is to return the nitrification liquid to the front end, and realize the denitrification removal of total nitrogen in the front-end biological reaction tank; there are two nitrification liquid return tanks, and the method of selecting the biological reaction tank as the nitrification liquid return tank is: when the total number of biological reaction tanks is 3-5, the first to last and the second to last biological reaction tanks are selected as nitrification liquid return tanks; when the total number of biological reaction tanks is 6-9, the first to last and the third to last biological reaction tanks are selected as nitrification liquid return tanks; when the total number of biological reaction tanks is 10-15, the first to last The first and fourth to last bioreactors are nitrification liquid return tanks; when the total number of bioreactors is 16-30, the first to last and fifth to last bioreactors are selected as nitrification liquid return tanks; by returning the nitrification liquid to the front-end bioreactor, denitrification removal of total nitrogen is achieved in the front-end bioreactor; wherein, the online monitoring device includes an online oxidation-reduction potential (ORP) meter, an online pH meter, and an online dissolved oxygen (DO) meter; the online monitoring device can provide optimal reaction conditions for the growth of microorganisms; wherein, the flocculation and sedimentation device is arranged at the subsequent end of the bioreactor unit, and the flocculation and sedimentation device includes several flocculation and sedimentation tanks 22; the function of the flocculation and sedimentation device is to remove suspended solids (SS) generated in the bioreactor, and at the same time, the phosphorus content in the water can be reduced by adding drugs, so that the effluent can meet the requirements of the unit effluent or the final effluent.

[0030] In this embodiment, there are 14 bioreactors of the same size and shape, with an aspect ratio of 2 and a depth of 5 m.

[0031] The filler 17 used in this embodiment is in the form of a cloth woven from fibers and fixed along its edge to the filler frame 16; the specific surface area of the filler 17 is ≥ 20000m 2 / kg. The fiber is a new polymer material with a hydrophilic surface modification. The fiber filler of this invention is carefully selected from materials outside the industry and has been repeatedly proven to be effective, with a service life of over 10 years guaranteed. The fiber filler and filler frame function as a carrier for microbial attachment, providing the necessary contact area for sufficient reaction between microorganisms and pollutants.

[0032] In this embodiment, there are two nitrification liquid reflux tanks, namely: a first nitrification liquid reflux tank 6A and a second nitrification liquid reflux tank 7B; the first nitrification liquid reflux tank 6A is connected to the front-end biological reaction tank 1A through a first nitrification liquid reflux pipe 8; the second nitrification liquid reflux tank 7B is connected to the front-end biological reaction tank 1A through a second nitrification liquid reflux pipe 12; the first nitrification liquid reflux pipe 8 is provided with a first nitrification liquid reflux pump 9, a first nitrification liquid flowmeter 11 and a first nitrification liquid reflux valve 10; the second nitrification liquid reflux pipe 12 is provided with a second nitrification liquid reflux pump 13, a second nitrification liquid flowmeter 15 and a second nitrification liquid reflux valve 14.

[0033] In this embodiment, an ORP online meter 19 and a first pH online meter 18 are installed in the front-end bioreactor 1A; a DO online meter 21 and a second pH online meter 20 are installed in the rear-end bioreactor 7B. Testing can also be performed in other bioreactors, but this is not essential.

[0034] The direction of water flow Figure 1 In the example shown, the upper arrow on the far left is the direction of sewage inlet, and the two arrows below are the direction of nitrification liquid return.

[0035] The wastewater flows through the bioreactors, entering bioreactor 1B through water distribution holes 6 at the bottom of bioreactor 1A. It then flows through triangular overflow trough 7 at the top of bioreactor 1B into bioreactor 2A, and finally into bioreactor 7B through water distribution holes 6 at the bottom of bioreactor 7A. Finally, water of suitable quality is discharged from flocculation sedimentation tank 22, where excess sludge is discharged.

[0036] While 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 these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A low-carbon in-situ sludge reduction sewage treatment device, characterized in that: It includes the following parts: biological reaction unit, filler rack device, aeration device, online monitoring device, flocculation sedimentation device; The bioreactor unit comprises 3-30 rectangular bioreactor tanks, each of which shares a common wall. A plurality of water distribution holes are uniformly arranged at 1 / 10-1 / 5 of the bottom of the common wall between the odd-numbered bioreactor tanks and the even-numbered bioreactor tanks; and a plurality of triangular overflow troughs are uniformly arranged at 1 / 20-1 / 10 of the top of the common wall between the even-numbered bioreactor tanks and the odd-numbered bioreactor tanks. A packing rack device, comprising a packing rack and packing on the packing rack; the packing rack device is evenly arranged in each bioreactor, and the packing rack plane is a series of standardized modules of 1×1m, 1×2m, 2×2m, 2×3m or 3×3m; The aeration device includes an aerator, an aeration branch pipe, and an aeration pipe valve; the aerator is arranged at the bottom of each biological reaction tank, the aerator is connected to the aeration branch pipe, and the aeration pipe valve is on the aeration branch pipe; Online monitoring device: including ORP online meter, pH online meter and DO online meter; Flocculation and sedimentation device: arranged at the subsequent end of the biological reaction unit, the flocculation and sedimentation device includes a plurality of flocculation and sedimentation tanks; Selecting several of the biological reaction pools as nitrification liquid reflux pools; connecting the nitrification liquid reflux pools to the front biological reaction pool via nitrification liquid reflux pipes; and one of the nitrification liquid reflux pools as the rear biological reaction pool; The filler is in the form of a cloth woven from fibers and fixed on the filler frame along its edge; the specific surface area of the filler is ≥20,000 m 2 / kg.

2. The low-carbon in-situ sludge reduction sewage treatment device according to claim 1 is characterized in that: There are two nitrification liquid return pools. The method of selecting the biological reaction pool as the nitrification liquid return pool is: When the total number of biological reaction tanks is 3-5, the first to last and the second to last biological reaction tanks are selected as nitrification liquid return tanks; when the total number of biological reaction tanks is 6-9, the first to last and the third to last biological reaction tanks are selected as nitrification liquid return tanks; when the total number of biological reaction tanks is 10-15, the first to last and the fourth to last biological reaction tanks are selected as nitrification liquid return tanks; when the total number of biological reaction tanks is 16-30, the first to last and the fifth to last biological reaction tanks are selected as nitrification liquid return tanks.

3. The low-carbon in-situ sludge reduction sewage treatment device according to claim 1 is characterized in that: There are 14 biological reaction tanks, which are identical in size and shape.

4. The low-carbon in-situ sludge reduction sewage treatment device according to claim 3 is characterized in that: There are two nitrification liquid reflux pools: a first nitrification liquid reflux pool and a second nitrification liquid reflux pool; The first nitrification liquid reflux tank is connected to the front-end biological reaction tank through a first nitrification liquid reflux pipe; the second nitrification liquid reflux tank is connected to the front-end biological reaction tank through a second nitrification liquid reflux pipe; the first nitrification liquid reflux pipe is provided with a first nitrification liquid reflux pump and a first nitrification liquid flow meter; the second nitrification liquid reflux pipe is provided with a second nitrification liquid reflux pump and a second nitrification liquid flow meter.

5. The low-carbon in-situ sludge reduction sewage treatment device according to claim 3 is characterized in that: An ORP online meter and a first pH value online meter are installed in the front-end bioreactor; a DO online meter and a second pH value online meter are installed in the rear-end bioreactor.

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