CN116119874A

CN116119874A - Wastewater treatment system for realizing resource recovery and carbon emission and related method

Info

Publication number: CN116119874A
Application number: CN202310062539.9A
Authority: CN
Inventors: 姚宏; 蔡伟伟; 韩翔宇; 张静静
Original assignee: Beijing Jiaotong University
Current assignee: Beijing Jiaotong University
Priority date: 2023-01-13
Filing date: 2023-01-13
Publication date: 2023-05-16

Abstract

The invention provides a wastewater treatment system for realizing resource recovery and carbon emission and a related method. The treatment system comprises a heat energy recovery module, a pretreatment impurity removal module, a sewage anaerobic digestion module, a deep denitrification module, a deep treatment module, a sludge decrement digestion module and a biogas purification module which are connected in sequence; the heat energy recovery module is used for recovering heat energy in sewage and thermal hydrolysis sludge; the pretreatment impurity removal module is used for removing large suspended solid substances and adjusting the pH of sewage; the sewage anaerobic digestion module is used for recycling carbon and phosphorus from sewage; the deep denitrification module is used for removing residual nitrogen elements in the sewage; the advanced treatment module is used for further removing the refractory pollutants in the water body and reaching the recycling standard; the sludge reduction digestion module is used for sludge reduction, biogas production and resource treatment; the biogas purification module is used for drying, storing, generating and recycling sulfur of biogas, and achieves the capacity effect of the sewage treatment plant while meeting the power consumption requirement of the sewage treatment plant.

Description

Wastewater treatment system for realizing resource recovery and carbon emission and related method

Technical Field

The invention relates to the technical field of wastewater treatment, in particular to a wastewater treatment system for realizing resource recovery and carbon emission and a related method.

Background

The sewage contains huge chemical energy, wherein the estimated energy which can be extracted reaches 28%, and the energy consumed in the running process of most sewage treatment plants is usually less than 50% of the extractable energy, so that the realization of energy neutrality and even energy output of the sewage treatment plants is completely feasible. Meanwhile, most sewage plants still utilize the traditional treatment process to carry out denitrification treatment at the present stage, besides the defect of high energy consumption, agents such as acetate, glucose and the like are additionally added to meet the treatment requirement, and the difficulty of subsequent treatment is increased due to high yield of residual sludge. The integral anaerobic ammonia oxidation process carried out at the present stage still has a plurality of technical bottlenecks in the main flow operation, so that the effluent quality fluctuates and is difficult to regulate and control, and the conditions of overhigh residual ammonia nitrogen concentration or nitrate accumulation are often caused.

The sewage treatment plant in the present stage mostly removes pollutants in water body at the cost of high energy consumption, and as the biological dephosphorization process in the traditional sewage treatment process contradicts with the demand of the biological denitrification process for oxygen, and the novel process such as anaerobic ammoxidation and the like does not have the dephosphorization function, most sewage treatment plants adopt the mode of adding the dephosphorization medicament to carry out chemical dephosphorization, thereby not only improving the operation cost, but also being contrary to the resource crisis consciousness of the 'phosphorus crisis', and being contrary to the trend of the 'resource recovery'.

In addition, the control method of the sewage plant at the present stage is mostly based on manual judgment of pollutant indexes of all functional units, has strong subjectivity and lacks foresight, often controls the effluent after the water quality fluctuates, and is excessively dependent on the relevant experience of practitioners.

Disclosure of Invention

In order to solve the technical problems, the invention provides a wastewater treatment system for realizing resource recovery and carbon emission and a related method.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:

the invention provides a wastewater treatment system for realizing resource recovery and carbon emission, which comprises a heat energy recovery module, a pretreatment impurity removal module, a sewage anaerobic digestion module, a deep denitrification module, a deep treatment module, a sludge decrement digestion module and a biogas purification module which are connected in sequence; the heat energy recovery module is used for recovering heat energy in sewage and reducing the temperature of water inflow, and recovering heat energy from high-temperature sludge after thermal hydrolysis of the sludge and reducing the temperature; the pretreatment impurity removal module is used for removing large suspended solid substances in the sewage, removing granular substances with the relative density of more than 1.5 and the particle size of more than 0.2mm in the sewage, and simultaneously adjusting the pH value of the sewage to 6-9; the sewage anaerobic digestion module is used for producing biogas and removing COD from sewage, and then removing phosphorus and recycling to produce magnesium ammonium phosphate; the deep denitrification module is used for removing ammonia nitrogen and nitrite nitrogen remained in the sewage; the advanced treatment module is used for removing most suspended matters, sludge and part of nondegradable organic particles in the sewage, removing residual nondegradable organic matters and pathogenic bacteria in the sewage, removing residual phosphate in the sewage, and further removing particles in the water body to reach the recycling standard; the sludge reduction digestion module is used for carrying out concentration treatment, thermal hydrolysis treatment and anaerobic digestion treatment on sludge and carrying out dehydration treatment on discharged materials; the biogas purification module is used for collecting biogas, sequentially carrying out wet desulfurization and dry desulfurization on the biogas, and then drying and storing the treated biogas.

Further, the sewage anaerobic digestion module comprises a first anaerobic digestion unit, a nitrogen and phosphorus recovery unit and a first sedimentation tank which are sequentially connected; the first anaerobic digestion unit is used for producing biogas and removing COD from sewage which is subjected to pretreatment and impurity removal of the module, and the produced biogas enters the biogas purification module; wherein the removal efficiency of the anaerobic digestion unit to COD is 85% -95%; the nitrogen and phosphorus recovery unit and the first sedimentation tank are used for dephosphorizing sewage passing through the first anaerobic digestion unit and recovering and producing magnesium ammonium phosphate, and then the sewage enters the deep denitrification module.

Further, the deep denitrification module comprises a sludge-film symbiotic integrated anaerobic ammonia oxidation unit, an aerobic granular sludge unit and a second sedimentation tank arranged behind the integrated anaerobic ammonia oxidation unit; the integrated anaerobic ammonia oxidation unit comprises anaerobic ammonia oxidation bacteria biological films attached to sponge fillers and ammonia oxidation bacteria in floccule sludge, wherein the floccule sludge is used for oxidizing part of ammonia nitrogen in sewage passing through a sewage anaerobic digestion module into nitrite nitrogen so as to enable the anaerobic ammonia oxidation bacteria to synchronously remove subsequent ammonia nitrogen and nitrite nitrogen, and the total nitrogen removal rate of the sewage reaches more than 90%; the sedimentation tank is used for keeping the reflux ratio of the sludge to the integrated anaerobic ammonia oxidation unit to be 100% -300%; the aerobic granular sludge unit operates in an SBR mode, is used for carrying out advanced treatment on nitrogen elements in sewage passing through the integrated anaerobic ammonia oxidation unit, and discharges the treated sewage into the advanced treatment module.

Further, the advanced treatment module comprises a high-efficiency filter, an electric-multiphase ozone catalytic device, a magnetic flocculation sedimentation tank and a membrane treatment unit which are connected in sequence; the high-efficiency filter is used for removing most suspended matters, sludge and part of nondegradable organic particles in the sewage passing through the deep denitrification module, so that the concentration of solid particles in the sewage is less than 30mg/L; the electric-multiphase ozone catalytic device is used for removing residual refractory organic matters and pathogenic bacteria in the sewage passing through the high-efficiency filter, and keeping the COD of the effluent of the sewage below 50 mg/L; the magnetic flocculation sedimentation tank is used for forming phosphate floccules through adding a dephosphorizing agent, removing residual phosphate in sewage passing through the electric-multiphase ozone catalytic device through a super magnetic separation technology, so that total phosphorus in the sewage is less than 0.5mg/L, and enabling the formed phosphate floccules and residual sludge to enter the sludge reduction module together; the membrane treatment unit is a microfiltration membrane with the aperture of 0.1-1 mu m and is used for removing particles in the sewage passing through the magnetic flocculation sedimentation tank so as to reach the recycling standard.

Further, the sludge reduction digestion module comprises a sludge concentration tank, a sludge thermal hydrolysis unit, a second anaerobic digestion unit, a dehydration unit and a biogas residue drying unit which are sequentially connected; the sludge concentration tank is used for concentrating sludge generated by the deep denitrification module and the deep treatment module to obtain mud cakes; the sludge thermal hydrolysis unit is used for carrying out thermal hydrolysis treatment on the mud cake to obtain sludge again, discharging the sludge into the heat energy recovery module for cooling, and uniformly mixing the cooled sludge with the pulped kitchen waste and introducing the mixture into the anaerobic digestion unit; the second anaerobic digestion unit is used for carrying out anaerobic digestion treatment on the cooled sludge and the kitchen waste after pulping, and producing biogas residues; the dehydration unit is used for carrying out dehydration treatment on the biogas residues so that the water content of the biogas residues is less than 50%; the biogas residue drying unit is used for drying the biogas residue passing through the dehydration unit so that the water content of the biogas residue is less than 10%; and a water seal device is arranged behind the first anaerobic digestion unit and the second anaerobic digestion unit and is used for preventing the pressure abnormality of the reactor.

Further, the biogas purification module comprises a wet desulfurization tower, a dry desulfurization tower, a dehydration tank and a double-membrane gas holder which are sequentially connected; the wet desulfurization tower is used for absorbing the sulfur-containing gas in the biogas by reacting with sodium carbonate, and oxidizing sulfide into elemental sulfur for precipitation; the dry desulfurization tower is used for further removing hydrogen sulfide in the biogas passing through the wet desulfurization tower, so that the wet desulfurization towerThe content of hydrogen sulfide in the biogas is less than 50mg/m ³ The method comprises the steps of carrying out a first treatment on the surface of the The dehydration tank is used for drying the biogas passing through the dry desulfurization tower; the double-membrane gas holder is used for storing the biogas passing through the dehydration tank.

Further, the heat energy recovery module comprises a heat exchanger and a cogeneration unit, wherein the heat exchanger is used for recovering heat energy in sewage entering the treatment system and reducing the temperature of inflow water, and also recovering heat energy and reducing the temperature of high-temperature sludge passing through the sludge reduction digestion module; the heat and power cogeneration unit is used for synchronously generating electricity and heat, and the heat energy recovered by the heat exchanger are output together as a high-quality heat source; the pretreatment impurity removal module comprises a coarse and fine grating and a grit chamber, wherein the coarse and fine grating is used for removing large suspended solid matters in the sewage passing through the heat exchanger; the grit chamber is used for removing the particulate matters with the relative density of more than 1.5 and the particle size of more than 0.2mm in the sewage passing through the coarse and fine grids, and adjusting the pH value of the sewage to 6-9.

Further, the processing system also comprises an in-situ self-generating module and an intelligent control module, wherein the in-situ self-generating module generates power by biogas passing through the cogeneration unit; the intelligent control module is used for recording various water quality indexes and manually adjusting data through the water quality sensor of each module in the processing system by utilizing a neural network algorithm to carry out weight calculation, and completing control behavior modeling so as to realize intelligent management and control of the processing system.

The second aspect of the present invention provides a wastewater treatment method for realizing resource recovery and carbon emission, the treatment method comprising: recovering heat energy in sewage, reducing the temperature of water inlet, and recovering heat energy from high-temperature sludge after thermal hydrolysis of sludge and reducing the temperature; firstly removing large suspended solid matters in the sewage, then removing granular matters with the relative density of more than 1.5 and the particle size of more than 0.2mm in the sewage, and simultaneously adjusting the pH value of the sewage to 6-9; biogas production and COD removal are carried out on the sewage, and phosphorus removal and recovery are carried out to produce magnesium ammonium phosphate; removing the ammonia nitrogen, nitrite nitrogen and nitrate nitrogen remained in the sewage; removing most suspended matters, sludge and part of nondegradable organic particles in the sewage, removing residual nondegradable organic matters and pathogenic bacteria in the sewage, removing residual phosphate in the sewage, and further removing particles in a water body to reach a recycling standard; concentrating, thermally hydrolyzing and anaerobically digesting the sludge, and dehydrating the discharged material; collecting methane, sequentially carrying out wet desulfurization and dry desulfurization on the methane, and then drying and storing the treated methane.

A third aspect of the present invention provides an intelligent control method for a wastewater treatment system for achieving resource recovery and carbon negative emission, the control method comprising a learning and verification stage, and an operation stage: wherein the learning and verification phase comprises: s1, monitoring and recording pollutant indexes and natural environment indexes of all units in the treatment system; s2, adjusting the parameters with abnormal processing effects in the units, and continuously optimizing algorithm weights by taking indexes of the parameters with the processing effects as training learning samples; predicting future water quality fluctuation based on the existing water quality data by utilizing a moving average model, and early warning the possible water quality abnormal condition to obtain a determined model weight parameter and a water quality prediction model so as to form a database; s3, monitoring whether parameters in the learning and verification process reach standards; s4, if the parameters reach the standards, recording the parameters; if the parameters do not reach the standards, returning to the step S2; the operation phase comprises: s5, monitoring and recording water inflow indexes and temperature conditions of all units in the treatment system; s6, automatically predicting and adjusting operation parameters according to the database; s7, monitoring whether parameters in the running process reach standards; s8, if the parameters reach the standards, discharging and recording the parameters; and S9, if the parameters do not reach the standards, returning to the step S2 after fault diagnosis is carried out.

Compared with the prior art, the technical scheme provided by the invention has at least the following advantages:

the invention provides a wastewater treatment system for realizing resource recovery and carbon emission and a related method. The energy in the sewage is widely extracted by utilizing technologies such as anaerobic digestion, sewage heat exchange and the like, and renewable energy sources such as wind-light power generation and the like are coupled to supply power to power consumption equipment in a low-energy-consumption deep denitrification process taking anaerobic ammonia oxidation and aerobic granular sludge as cores and a phosphorus and sulfur recovery process, so that a sewage plant can realize high-efficiency recovery of carbon, phosphorus and sulfur without depending on external power supply, and simultaneously, the negative carbon emission is met, and the effluent reaches the recycling standard. And an intelligent control system of the sewage plant is constructed through a neural network algorithm, so that intelligent efficient operation, maintenance and management are realized.

According to the invention, the organic carbon in the sewage and the sludge is respectively extracted through the two anaerobic digestion units, so that the chemical energy in the sewage is recovered to the maximum extent. Compared with the traditional process that organic matters in sewage are removed through aeration, the method provided by the invention has the advantages that the biogas productivity is recovered, and meanwhile, the operation energy consumption caused by operations such as aeration and the like is greatly reduced; compared with the problems of large occupied area, difficult transportation, air pollution and the like caused by compression, drying and incineration in the traditional sludge treatment process, the invention utilizes the sludge thermal hydrolysis technology to break the cell walls of microorganisms in the sludge serving as a substrate, so that the methane is produced more thoroughly, the chemical energy in the sludge is extracted to the maximum extent, the sludge is subjected to reduction treatment, and the burden of back-end treatment is reduced. Meanwhile, the biogas residue can be dried at high temperature and used as a fertilizer for landscape architecture for resource utilization.

The invention is additionally provided with the nitrogen and phosphorus recovery unit and the wet desulfurization (sulfur recovery) unit in the marsh gas, and compared with the design aiming at removal in the traditional sewage treatment process, the invention reduces the cost and the carbon emission caused by adding the medicament. The recovered product can be produced as industrial raw materials such as chemical fertilizers, and the resource recovery is realized to the greatest extent on the basis of meeting the standards of pollutant removal and treatment.

The invention constructs a deep denitrification system by taking the integrated anaerobic ammonia oxidation and aerobic granular sludge as cores, wherein the anaerobic ammonia oxidation system has the advantage of metabolic pathway, can reduce the aeration energy consumption by 60 percent compared with the traditional sewage treatment process, does not need to additionally add a carbon source, and has remarkable low-carbon emission advantage. In the prior integrated anaerobic ammonia oxidation process, the condition of fluctuation of the water quality of the effluent (incomplete ammonia nitrogen removal or nitrate accumulation and the like) exists in the actual operation process, so that the rear end of the integrated anaerobic ammonia oxidation process is often accompanied with a first-stage AO process to further denitrify. The patent proposes an alternative process with aerobic granular sludge as AO, which can reduce 50% of energy consumption (generated by a reflux pump and a stirrer) and 75% of occupied area again, and realize ammonia nitrogen removal in a high-efficiency and low-carbon manner.

The multi-phase electro-ozone catalysis technology is used as a core technology of advanced treatment, toxic substances which are difficult to remove by biological treatment are effectively oxidized and degraded, and the technology comprises sterilization, so that pathogenic microorganisms in sewage are prevented from entering natural water or recycled water. Compared with the chlorination in the traditional process, the technology can avoid the problem of residual chlorine in the water body and prevent corrosion to subsequent process structures or reuse water pipelines. The chlorine disinfectant does not need to be purchased additionally, so that the cost is saved and the carbon emission is reduced. Compared with the traditional ozone disinfection, the technology can efficiently remove ozone inert novel pollutants (such as ibuprofen and the like), and the pollutant removal rate of the traditional ozone process difficult to oxidize is improved by more than 40%. Meanwhile, a membrane treatment system is added at the rear end, so that the sewage filtering effect and efficiency are improved, and the recycling standard is achieved.

The heat recovery technology of cogeneration, sewage heat exchange and the like is included in the patent, so that the energy efficiency of methane power generation is improved, and meanwhile, the heat exchanger is utilized to perform heat exchange on high-temperature industrial wastewater inflow water such as fermentation, coal chemical industry and the like, so that a high-quality heat source is provided for the working requirements of reactor heat preservation, sludge thermal hydrolysis, factory heat supply and the like.

Drawings

One or more embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, which are not to be construed as limiting the embodiments unless specifically indicated otherwise.

FIG. 1 is a block diagram of a wastewater treatment system for implementing resource recovery and carbon emission according to an embodiment of the present invention;

FIG. 2 is a flow chart of an intelligent control method for a wastewater treatment system for implementing resource recovery and carbon negative emission, provided by an embodiment of the invention.

In the figure, a 1-heat exchanger, a 2-coarse and fine grid, a 3-grit chamber, a 4-first anaerobic digestion unit, a 5-nitrogen and phosphorus recovery unit, a 6-first sedimentation tank, a 7-integrated anaerobic ammonia oxidation unit, an 8-second sedimentation tank, a 9-aerobic granular sludge unit, a 10-high efficiency filter, an 11-electric-multiphase ozone catalytic device, a 12-magnetic flocculation sedimentation tank, a 13-membrane treatment unit, a 14-sludge concentration tank, a 15-sludge thermal hydrolysis unit, a 16-second anaerobic digestion unit, a 17-dehydration unit, a 18-biogas residue drying unit, a 19-water seal device, a 20-wet desulfurization tower, a 21-dry desulfurization tower, a 22-dehydration tank, a 23-double-membrane gas holder, a 24-cogeneration unit and a 25-wind-light power generation unit.

Detailed Description

The inventor finds that the existing sewage treatment process mostly removes various pollutants containing nitrogen, carbon, phosphorus and sulfur at the cost of high energy consumption, although a better removal effect is achieved, and the development of the future sewage treatment process tends to achieve resource recovery and energy recovery while removing the pollutants with low energy consumption. The invention provides a sewage treatment system capable of realizing high-efficiency recovery of carbon, phosphorus and sulfur elements in sewage and realizing carbon emission by coupling a low-carbon denitrification process.

In the prior art, the sewage treatment process does not simultaneously realize the efficient recovery of carbon, phosphorus and sulfur, and simultaneously, the energy consumption of the denitrification unit is large, so that a great amount of energy waste is caused. For example, a set of municipal sewage treatment system capable of realizing carbon and phosphorus recovery and reclaimed water recycling is designed in China national invention patent (CN 111875152A), but synchronous recovery of sulfur is not considered, and thus, the hydrogen sulfide gas in methane can cause atmospheric pollution in subsequent combustion and use. In addition, the high-efficiency composite denitrification unit in the patent uses five good/lack/anaerobic reaction tanks, occupies a large area and needs higher aeration energy consumption. Meanwhile, the sodium hypochlorite sterilization system of the advanced treatment unit is difficult to remove novel pollutants such as ibuprofen and other inert medicines. Unlike the above patent, this patent recovers biogas by anaerobic digestion of pre-wastewater (anaerobic digestion 1) in a process design, reduces carbon loss of subsequent biological treatment units due to microbial respiration, enables the process to adapt to high organic load water inflow conditions (COD >3000 mg/L), and recovers organics immobilized in biological systems by anaerobic digestion of sludge (anaerobic digestion 2). Meanwhile, the wet desulphurization device is used for recycling sulfur paste for the biogas, so that sulfur recycling is realized, and harmful gas emission caused in the biogas use process is reduced. Aiming at the denitrification unit, the invention adopts an integrated anaerobic ammonia oxidation (IFAS-CANON) process of mud-film symbiosis, compared with the traditional sewage treatment process, the aeration energy consumption can be reduced by 60%, the occupied area is small, and no additional carbon source is needed. In the subsequent advanced treatment stage, an electro-multi-ozone catalytic process is adopted, so that various ozone inert pollutants can be effectively removed, and the problem of residual chlorine is avoided.

As in the chinese national invention patent (CN 114149143 a), a low-carbon sewage treatment system is designed, which can improve the extraction degree of the residual sludge through the thermal hydrolysis and co-digestion process of the sludge, and simultaneously adopts a denitrification system with anaerobic ammoxidation as a core, so that the occupied area and the aeration energy consumption are greatly reduced, but the design of the system does not consider the efficient recovery of phosphorus and sulfur, and has great limitation on the treatment of sewage with high organic load. In addition to the advantages, the invention aims at solving the problem that ammonia nitrogen and nitrate nitrogen in the effluent of the anaerobic ammonia oxidation process are difficult to reach the standard directly, and an aerobic granular sludge treatment unit is additionally arranged for advanced treatment, so that compared with the advanced denitrification by arranging an AO process at the rear end of the conventional anaerobic ammonia oxidation process, the process can reduce the energy consumption by 50% and the occupied area by 75% again. The system is characterized in that the effluent water is connected with a membrane treatment system (microfiltration membrane treatment, aperture is 0.1-1 μm), and the particulate matters and microorganisms in the sewage are further treated, so that the effluent water reaches the recycling standard and the occupied area of a sedimentation tank in the traditional process flow is reduced.

The present invention will be described in detail with reference to the following embodiments.

An industrial wastewater treatment system for realizing resource recovery and carbon negative emission, as shown in fig. 1, comprises:

and (one) a heat energy recovery module: the heat energy recovery module of the sewage treatment system consists of two parts. Firstly, industrial wastewater (such as starch wastewater, coking wastewater, coal chemical wastewater, pharmaceutical wastewater and the like) with the temperature of more than 35 ℃ needs to exchange heat through a tubular heat exchanger 1 before entering a treatment process, heat energy in the wastewater is recovered, and the water inlet temperature is reduced (< 25 ℃) so as to prevent the effect of a subsequent microorganism treatment system from being influenced; secondly, the high-temperature sludge (120-200 ℃) after thermal hydrolysis of the sludge also needs a heat exchanger 1 to recycle heat energy and cool; finally, the present invention utilizes the cogeneration unit 24 in the methane power generation system, and can synchronously generate electricity and heat, and output the heat as a high-quality heat source together with the recovered heat energy.

And (II) a pretreatment impurity removal module: the sewage enters the module after heat exchange by the heat exchanger 1, firstly large suspended solid matters in the water are removed by the coarse and fine gratings 2, and then enter the grit chamber 3 to remove the granular matters (such as inorganic sand grains, fruit pits and the like) with the relative density of more than 1.5 and the grain diameter of more than 0.2mm, and meanwhile, the pH value is adjusted to 6-9.

And (III) a sewage anaerobic digestion module: sewage flows into the first anaerobic digestion unit 4 for biogas production after passing through the pretreatment impurity removal module, the hydraulic retention time is 20h, and the removal efficiency of COD is 85% -95%. The generated biogas enters a biogas purification module for further impurity removal, and the sewage enters a deep denitrification module after dephosphorization and recovery of magnesium ammonium phosphate (struvite) by a nitrogen and phosphorus recovery unit 5 and a first sedimentation tank 6.

(IV) a deep denitrification module: the module consists of a sludge-membrane symbiotic integrated anaerobic ammonia oxidation (IFAS-CANON) unit 7 and an aerobic granular sludge unit 9. The IFAS-CANON unit 7 is filled with spongy filler, anaerobic ammonia oxidizing bacteria on the surface of the IFAS-CANON unit form a biological film, ammonia nitrogen and nitrite nitrogen are synchronously removed by the biological film, and the unit can ensure that the total nitrogen removal rate of sewage is more than 90% under the condition that an external carbon source is not added, wherein the nitrite nitrogen is derived from ammonia oxidizing bacteria contained in floccule sludge in the IFAS-CANON unit 7. The unit only needs micro aeration, the concentration of dissolved oxygen is kept between 0.3mg/L and 0.8mg/L, and if the nitrate nitrogen in the effluent is too high or the nitrite nitrogen is accumulated, the concentration of the dissolved oxygen is adjusted to be less than 0.5mg/L. The rear part is provided with a second sedimentation tank 8, and the reflux ratio of the sludge to the IFAS-CANON unit is kept to be 100-300%. The process effluent still contains a small part of ammonia nitrogen which is less than 40mg/L and nitrate nitrogen which is less than 100mg/L, so that an aerobic granular sludge unit 9 is arranged at the rear end to carry out advanced treatment on nitrogen elements. The aerobic granular sludge unit 9 operates in an SBR mode, the dissolved oxygen in the aeration stage is kept between 4mg/L and 6mg/L, the dissolved oxygen in the anaerobic stage is less than 0.5mg/L, and the sludge concentration in the system is not lower than 4000mg/L (wherein the particle ratio is more than 75%) during operation. Since the aerobic granular sludge unit 9 has good sedimentation performance (sedimentation rate is more than 50 m/h), a sedimentation tank is not required to be arranged at the rear end.

And (V) an advanced treatment module: the advanced treatment module comprises a high-efficiency filter 10, an electric-multiphase ozone catalytic device 11, a magnetic flocculation sedimentation tank 12 and a membrane treatment unit 13. The high-efficiency filter 10 removes most suspended matters, sludge and part of nondegradable organic particles in the sewage, so that the concentration of solid particles is less than 30mg/L, and the subsequent treatment difficulty is greatly reduced. The gas (ozone concentration is 100 mg/L) generated by the ozone generator is continuously introduced into the electric-multiphase ozone catalytic device 11 from the anode, and a large amount of hydroxyl free radicals are formed on the surface of the electrode, so that residual refractory organic matters (40% higher than pure ozone catalytic removal rate and ozone inert substances removal) and pathogenic bacteria in the sewage can be effectively removed, and the COD of the effluent of the unit can be kept at 50mg/L. The magnetic flocculation sedimentation tank 12 can form phosphate flocculate through adding a dephosphorizing agent, and remove residual phosphate in the sewage (the total phosphorus in the water is less than 0.5 mg/L) through a super magnetic separation technology, the phosphate flocculate and the residual sludge enter a sludge reduction digestion module together, and the sewage is treated by a membrane treatment unit 13 (a microfiltration membrane with the aperture of 0.1-1 μm) to further remove particles in the water and reach the recycling standard.

And (six) a sludge reduction digestion module: the back end sediment Chi Paini of the IFAS-CANON unit 7, the sludge discharged by the aerobic granular sludge unit 9, the retentate of the high-efficiency filter 10 and the sludge discharged by the magnetic flocculation sedimentation tank 12 all enter a sludge decrement digestion module to carry out 'resource recovery', 'energy extraction' and 'harmless treatment'. The sludge firstly enters a sludge thickening tank 14 for thickening, the water content of a preferable mud cake after the thickening treatment is about 80% -88%, the mud cake enters a sludge thermal hydrolysis unit 15 for reacting for 30-60 min, and the temperature is kept at 120-200 ℃. The sludge after thermal hydrolysis is cooled to 40-45 ℃ by a heat exchanger 1, and then is evenly mixed with the kitchen waste after pulping and is introduced into a second anaerobic digestion unit 16. The anaerobic digestion hydraulic retention time is about 7-12 d, the operation temperature is kept at 35-40 ℃ during the anaerobic digestion hydraulic retention time, and the biogas is continuously collected to the biogas purification module. The discharged material (biogas residue) after anaerobic digestion is treated by a dehydration unit 17 until the water content is less than 50%, the biogas slurry and sewage are mixed and enter a second anaerobic digestion unit 16 for further treatment, the biogas residue enters a biogas residue drying unit 18, and the temperature of a drying system is kept at 100-200 ℃ to enable the water content to be less than 10%, so that the biogas residue is used as nutrient soil for recycling.

And (seventh) a biogas purification module: the tail ends of the first anaerobic digestion unit 4 and the second anaerobic digestion unit 16 are connected with a water seal 19 to prevent the pressure abnormality of the reactor, then the marsh gas enters a wet desulphurization tower 20, the sulfur-containing gas in the marsh gas reacts with sodium carbonate to be absorbed, then the solution is sprayed out of the reactor at the speed of 25m/s and is completely mixed with air, so that sulfide is oxidized into elemental sulfur to be separated out, the high-efficiency recovery of sulfur elements in sewage is realized, and the sulfur separation amount accounts for the total sulfur>75%. Then the hydrogen sulfide in the gas is further removed by a dry desulfurizing tower 21 to ensure that the hydrogen sulfide content in the methane<50mg/m ³ . The biogas is then dried by a dehydration tank 22 and stored in a double membrane gas holder 23.

(eight) in-field self-generating module: the biogas generated by the above-mentioned unit 24 generates electricity through the cogeneration unit, the electric power supplies the power grid of the factory, in addition, there is wind-light generating unit 25, can meet the steady operation of each module, unit equipment in the sewage treatment flow, and the factory office building, dining room, dormitory use, can also incorporate the external supply of the electric power grid.

And (nine) an intelligent control module: the processing system also comprises an intelligent control module of the flow facility, wherein the module can record various water quality indexes through water quality sensors in each module and unit, and the intelligent control function is finally realized by manually adjusting the water quality indexes and mutually matching the water quality indexes through a neural network model algorithm. The module is divided into three phases: as shown in fig. 2, in the learning stage, the module continuously records pollutant indexes and natural environment indexes of each processing unit and manually adjusts operation conditions aiming at abnormal processing effects, and takes the pollutant indexes and natural environment indexes as training learning samples to continuously optimize algorithm weights; in the verification stage, the whole sewage treatment module still needs to be manually regulated and operated, the algorithm can stop recording data and verify the accuracy of the model according to the existing weight, the learning stage can be re-entered if the abnormal situation occurs too much, and the stage is considered to be ended when the recording days are more than 50d and the accuracy is higher than 98%. In the two stages, the module predicts future water quality fluctuation based on the existing water quality data by utilizing a moving average model and early warns about water quality abnormality possibly occurring; the third stage is an operation stage, and the module can implement pre-regulation and control on each unit of the sewage treatment system according to the model weight parameters and the water quality prediction model determined in the stages, and complete operation before abnormality occurs in the treatment unit, so that the occurrence frequency of water outlet fluctuation can be greatly reduced, and the corresponding cost is reduced.

It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples of implementing the present application and that various changes in form and details may be made therein without departing from the spirit and scope of the present application. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention, and the scope of the invention shall be defined by the appended claims.

Claims

1. The wastewater treatment system for realizing resource recovery and carbon emission is characterized by comprising a heat energy recovery module, a pretreatment impurity removal module, a sewage anaerobic digestion module, a deep denitrification module, a deep treatment module, a sludge decrement digestion module and a biogas purification module which are sequentially connected;

the heat energy recovery module is used for recovering heat energy in sewage and reducing the temperature of water inflow, and recovering heat energy from high-temperature sludge after thermal hydrolysis of the sludge and reducing the temperature;

the pretreatment impurity removal module is used for removing large suspended solid substances in the sewage, removing granular substances with the relative density of more than 1.5 and the particle size of more than 0.2mm in the sewage, and simultaneously adjusting the pH value of the sewage to 6-9;

the sewage anaerobic digestion module is used for producing biogas and removing COD from sewage, and then removing phosphorus and recycling to produce magnesium ammonium phosphate;

the deep denitrification module is used for removing ammonia nitrogen and nitrite nitrogen remained in the sewage;

the advanced treatment module is used for removing most suspended matters, sludge and part of nondegradable organic particles in the sewage, removing residual nondegradable organic matters and pathogenic bacteria in the sewage, removing residual phosphate in the sewage, and further removing particles in the water body to reach the recycling standard;

the sludge reduction digestion module is used for carrying out concentration treatment, thermal hydrolysis treatment and anaerobic digestion treatment on sludge and carrying out dehydration treatment on discharged materials;

the biogas purification module is used for collecting biogas, sequentially carrying out wet desulfurization and dry desulfurization on the biogas, and then drying and storing the treated biogas.

2. The wastewater treatment system for realizing resource recovery and carbon emission according to claim 1, wherein the sewage anaerobic digestion module comprises a first anaerobic digestion unit (4), a nitrogen and phosphorus recovery unit (5) and a first sedimentation tank (6) which are sequentially connected;

the first anaerobic digestion unit (4) is used for producing biogas and removing COD from the sewage subjected to the pretreatment impurity removal module, and the produced biogas enters the biogas purification module; wherein the removal efficiency of the anaerobic digestion unit to COD is 85% -95%;

the nitrogen and phosphorus recovery unit (5) and the first sedimentation tank (6) are used for dephosphorizing sewage passing through the first anaerobic digestion unit (4) and recovering and producing magnesium ammonium phosphate, and then the sewage enters the deep denitrification module.

3. The wastewater treatment system for realizing resource recovery and carbon negative emission according to claim 1, wherein the deep denitrification module comprises an integrated anaerobic ammonia oxidation unit (7) and an aerobic granular sludge unit (9) for sludge membrane symbiosis, and a second sedimentation tank (8) arranged after the integrated anaerobic ammonia oxidation unit;

the integrated anaerobic ammonia oxidation unit (7) comprises anaerobic ammonia oxidation bacteria biological membranes attached to sponge fillers and ammonia oxidation bacteria in floccule sludge, wherein the floccule sludge is used for oxidizing part of ammonia nitrogen in sewage passing through a sewage anaerobic digestion module into nitrite nitrogen so as to enable the anaerobic ammonia oxidation bacteria to synchronously remove subsequent ammonia nitrogen and nitrite nitrogen, and the total nitrogen removal rate of the sewage reaches more than 90%;

the sedimentation tank (8) is used for keeping the reflux ratio of the sludge to the integrated anaerobic ammonia oxidation unit (7) to be 100% -300%;

the aerobic granular sludge unit (9) operates in an SBR mode and is used for carrying out advanced treatment on nitrogen elements in sewage passing through the integrated anaerobic ammonia oxidation unit (7) and discharging the treated sewage into the advanced treatment module.

4. The wastewater treatment system for realizing resource recovery and carbon emission according to claim 1, wherein the advanced treatment module comprises a high-efficiency filter (10), an electric-multiphase ozone catalytic device (11), a magnetic flocculation sedimentation tank (12) and a membrane treatment unit (13) which are connected in sequence;

the efficient filter (10) is used for removing most suspended matters, sludge and part of nondegradable organic particles in the sewage passing through the deep denitrification module, so that the concentration of solid particles in the sewage is less than 30mg/L;

the electro-multiphase ozone catalytic device (11) is used for removing residual refractory organic matters and pathogenic bacteria in the sewage passing through the high-efficiency filter (10) and keeping the COD of the effluent of the sewage below 50 mg/L;

the magnetic flocculation sedimentation tank (12) is used for forming phosphate floccules through adding a dephosphorizing agent, removing residual phosphate in sewage passing through the electric-multiphase ozone catalytic device through a super-magnetic separation technology so that the total phosphorus in the sewage is less than 0.5mg/L, and enabling the formed phosphate floccules and residual sludge to enter the sludge reduction module together;

the membrane treatment unit (13) is a microfiltration membrane with the aperture of 0.1-1 mu m, and is used for removing particles in the sewage passing through the magnetic flocculation sedimentation tank so as to reach the recycling standard.

5. The wastewater treatment system for realizing resource recovery and carbon emission according to claim 2, wherein the sludge reduction digestion module comprises a sludge concentration tank (14), a sludge thermal hydrolysis unit (15), a second anaerobic digestion unit (16), a dehydration unit (17) and a biogas residue drying unit (18) which are sequentially connected;

the sludge concentration tank (14) is used for concentrating sludge generated by the deep denitrification module and the deep treatment module to obtain mud cakes;

the sludge thermal hydrolysis unit (15) is used for carrying out thermal hydrolysis treatment on the mud cake to obtain sludge again, discharging the sludge into the heat energy recovery module for cooling, and uniformly mixing the cooled sludge with the pulped kitchen waste and introducing the mixture into the anaerobic digestion unit (16);

the second anaerobic digestion unit (16) is used for carrying out anaerobic digestion treatment on the cooled sludge and the kitchen waste after pulping, and producing biogas residues;

the dehydration unit (17) is used for carrying out dehydration treatment on the biogas residues so that the water content of the biogas residues is less than 50%, and re-introducing sewage generated by the dehydration treatment into the sewage anaerobic digestion module for treatment;

the biogas residue drying unit (18) is used for drying the biogas residue passing through the dehydration unit (17) so that the water content of the biogas residue is less than 10%;

and a water seal device (19) is arranged behind the first anaerobic digestion unit (4) and the second anaerobic digestion unit (16) and is used for preventing the pressure abnormality of the reactor.

6. The wastewater treatment system for realizing resource recovery and carbon emission according to claim 1, wherein the biogas purification module comprises a wet desulfurization tower (20), a dry desulfurization tower (21), a dehydration tank (22) and a double-membrane gas holder (23) which are connected in sequence;

the wet desulfurization tower (20) is used for absorbing the sulfur-containing gas in the biogas by reacting with sodium carbonate and oxidizing sulfide into elemental sulfur for precipitation;

the dry desulfurization tower (21) is used for further removing hydrogen sulfide in the biogas passing through the wet desulfurization tower (20) so that the content of the hydrogen sulfide in the biogas is less than 50mg/m ³ ；

The dehydration tank (22) is used for drying the biogas passing through the dry desulfurization tower (21);

the double-membrane gas holder (23) is used for storing the biogas passing through the dehydration tank (22).

7. The wastewater treatment system for realizing resource recovery and carbon negative emission according to claim 1, wherein the heat energy recovery module comprises a heat exchanger (1) and a cogeneration unit (24), the heat exchanger (1) is used for recovering heat energy in wastewater entering the treatment system and reducing inflow water temperature, and also recovering heat energy and reducing temperature of high-temperature sludge passing through the sludge decrement digestion module; the cogeneration unit (24) is used for synchronously generating electricity and heat, and outputs the heat energy and the heat energy recovered by the heat exchanger (1) together as a high-quality heat source;

the pretreatment impurity removal module comprises a coarse and fine grating (2) and a grit chamber (3), wherein the coarse and fine grating (2) is used for removing large suspended solid matters in sewage passing through the heat exchanger (1); the grit chamber (3) is used for removing the particulate matters with the relative density of more than 1.5 and the particle size of more than 0.2mm in the sewage passing through the coarse and fine grids (1), and adjusting the pH value of the sewage to 6-9.

8. The wastewater treatment system for achieving resource recovery and carbon negative emission of claim 7 further comprising an on-site self-generating module and an intelligent control module, the on-site self-generating module generating electricity from biogas via the cogeneration unit (24); the intelligent control module is used for recording various water quality indexes and manually adjusting data through the water quality sensor of each module in the processing system by utilizing a neural network algorithm to carry out weight calculation, and completing control behavior modeling so as to realize intelligent management and control of the processing system.

9. A wastewater treatment method for realizing resource recovery and carbon emission, which is characterized by comprising the following steps:

recovering heat energy in sewage, reducing the temperature of water inlet, and recovering heat energy from high-temperature sludge after thermal hydrolysis of sludge and reducing the temperature;

firstly removing large suspended solid matters in the sewage, then removing granular matters with the relative density of more than 1.5 and the particle size of more than 0.2mm in the sewage, and simultaneously adjusting the pH value of the sewage to 6-9;

biogas production and COD removal are carried out on the sewage, and phosphorus removal and recovery are carried out to produce magnesium ammonium phosphate;

removing the ammonia nitrogen, nitrite nitrogen and nitrate nitrogen remained in the sewage;

removing most suspended matters, sludge and part of nondegradable organic particles in the sewage, removing residual nondegradable organic matters and pathogenic bacteria in the sewage, removing residual phosphate in the sewage, and further removing particles in a water body to reach a recycling standard;

concentrating, thermally hydrolyzing and anaerobically digesting the sludge, and dehydrating the discharged material;

collecting methane, sequentially carrying out wet desulfurization and dry desulfurization on the methane, and then drying and storing the treated methane.

10. An intelligent control method for a wastewater treatment system for achieving resource recovery and carbon negative emission, characterized in that the control method comprises a learning and verification stage, and an operation stage:

wherein the learning and verification phase comprises:

s1, monitoring and recording pollutant indexes and natural environment indexes of all units in the treatment system;

s2, adjusting the parameters with abnormal processing effects in the units, and continuously optimizing algorithm weights by taking indexes of the parameters with the processing effects as training learning samples; predicting future water quality fluctuation based on the existing water quality data by utilizing a moving average model, and early warning the possible water quality abnormal condition to obtain a determined model weight parameter and a water quality prediction model so as to form a database;

s3, monitoring whether parameters in the learning and verification process reach standards;

s4, if the parameters reach the standards, recording the parameters; if the parameters do not reach the standards, returning to the step S2;

the operation phase comprises:

s5, monitoring and recording water inflow indexes and temperature conditions of all units in the treatment system;

s6, automatically predicting and adjusting operation parameters according to the database;

s7, monitoring whether parameters in the running process reach standards;

s8, if the parameters reach the standards, discharging and recording the parameters;

and S9, if the parameters do not reach the standards, returning to the step S2 after fault diagnosis is carried out.