CN114890614A - Novel landfill leachate treatment system and treatment process thereof - Google Patents

Novel landfill leachate treatment system and treatment process thereof Download PDF

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CN114890614A
CN114890614A CN202210375636.9A CN202210375636A CN114890614A CN 114890614 A CN114890614 A CN 114890614A CN 202210375636 A CN202210375636 A CN 202210375636A CN 114890614 A CN114890614 A CN 114890614A
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nanofiltration
anaerobic
water
treatment
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樊星
安瑾
苏雅
常俊俊
武首任
陆飞鹏
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Everbright Envirotech China Ltd
Everbright Environmental Protection Research Institute Nanjing Co Ltd
Everbright Environmental Protection Technology Research Institute Shenzhen Co Ltd
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Everbright Envirotech China Ltd
Everbright Environmental Protection Research Institute Nanjing Co Ltd
Everbright Environmental Protection Technology Research Institute Shenzhen Co Ltd
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    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00Multistage treatment of water, waste water or sewage
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/44Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/442Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by nanofiltration
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/44Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/444Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/46Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/469Treatment of water, waste water, or sewage by electrochemical methods by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis
    • C02F1/4693Treatment of water, waste water, or sewage by electrochemical methods by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis electrodialysis
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00Treatment of water, waste water, or sewage
    • C02F1/72Treatment of water, waste water, or sewage by oxidation
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00Nature of the contaminant
    • C02F2101/10Inorganic compounds
    • C02F2101/101Sulfur compounds
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00Nature of the contaminant
    • C02F2101/30Organic compounds
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/06Contaminated groundwater or leachate
    • CCHEMISTRY; METALLURGY
    • C02TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02FTREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00Biological treatment of water, waste water, or sewage
    • C02F3/30Aerobic and anaerobic processes
    • C02F3/302Nitrification and denitrification treatment
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02ATECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A20/00Water conservation; Efficient water supply; Efficient water use
    • Y02A20/124Water desalination
    • Y02A20/131Reverse-osmosis

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  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)

Abstract

The invention discloses a novel landfill leachate treatment system and a treatment process thereof. Wherein the pretreatment unit is a grating well, in order to get rid of impurities in landfill leachate, the biochemical treatment unit comprises a sulfuric acid reduction type anaerobic unit and an autotrophic nitrogen removal AO unit, in order to get rid of system COD and ammonia nitrogen, the advanced treatment unit comprises an ultrafiltration, nanofiltration, electrodialysis, advanced oxidation and low-temperature evaporation unit, and when the COD is further got rid of, the removal and recovery of salt are realized. Wherein the nanofiltration concentrated water carries high-concentration sulfate ions to flow back to the anaerobic unit after being subjected to advanced oxidation to remove nondegradable COD, thereby providing conditions for the sulfuric acid reduction decarburization process and the autotrophic denitrification process. The invention has the advantages of good quality of effluent water in the whole process, no discharge of concentrated water, no need of an external carbon source for a biochemical unit, less sludge, stable operation of the whole system and low investment and operation cost.

Description

Novel landfill leachate treatment system and treatment process thereof
Technical Field
The invention relates to the technical field of environmental protection, in particular to a novel landfill leachate treatment system and a treatment process thereof.
Background
The landfill leachate refers to liquid seeped from garbage in a garbage landfill or a garbage bin of an incineration plant, and the sources of the liquid include self-contained moisture, rain and snow water entering the landfill, other moisture and the like, and the liquid is organic wastewater with high organic matter concentration, high ammonia nitrogen concentration and high salt.
At present, the landfill leachate treatment mostly adopts an anaerobic treatment and AO + advanced treatment process, and a series of membrane technologies are required to be utilized for advanced treatment after biochemical effluent is generated, so as to ensure that hardness and salinity in sewage are removed, and the effluent quality is ensured to reach the standard. However, the biochemical unit in the process has the problems of insufficient carbon source, large sludge yield, incomplete treatment and the like, meanwhile, a large amount of membrane concentrated solution can be generated by advanced treatment, if the 'ultrafiltration + nanofiltration + reverse osmosis' process is adopted, the total recovery rate is generally 60% -70%, concentrated water is generally continuously concentrated by a disc-tube type reverse osmosis DTRO membrane, the water production rate is generally 50%, a large amount of concentrated water cannot be absorbed, the membrane concentrated solution has the characteristics of high COD, high salinity, complex components and the like, the treatment and the absorption are difficult, and if the treatment is improper, the environment is seriously polluted, so that the method becomes a pain point and a difficulty point of each landfill or incineration plant.
Patent CN110818177A provides a landfill leachate treatment system, which adopts the technology of 'pretreatment unit-internal and external circulation anaerobic reactor-AO unit-ultrafiltration unit-electrodialysis unit-nanofiltration unit, electrodialysis concentrated water is evaporated, nanofiltration concentrated water returns to the A tank through a material membrane, and the material membrane concentrated water is burnt by a material membrane concentrated water incinerator'. According to the process, organic matters and ammonia nitrogen are removed through a biochemical treatment unit, the landfill leachate is treated through an advanced treatment unit to generate concentrated water, and the concentrated water subjected to electrodialysis, nanofiltration and material membrane concentrated water are respectively treated through a concentrated water treatment unit in an evaporation and incineration mode, so that the full treatment and zero discharge of the landfill leachate are realized. Although this patent realizes full-scale treatment and zero discharge, but utilized the incinerator of msw incineration factory to burn, dense water spouts the incinerator back and produces negative effects to the temperature etc. of burning process, and the composition such as organic matter inorganic salt in the dense water probably has influences such as coking, scale deposit to equipment such as incinerator, and this technology is only suitable for being applied to incineration factory landfill leachate, can not realize the complete absorption of dense water to landfill leachate of the condition of not burning such as landfill site or transfer station. In addition, the biochemical unit of the process adopts a normal anaerobic-AO system, and the problems of insufficient carbon source, incomplete denitrification, high sludge yield and the like in the conventional percolate treatment are not improved. Is quite different from the patent.
Patent CN208265976U provides a landfill leachate concentrate zero release processing system, the system includes pretreatment systems, equalizing basin, anaerobism system, MBR system, receive and filter membrane system and be used for handling the advanced oxidation desalination conjugation system of landfill leachate concentrate, and the concentrate of receiving the membrane system flows back to anterior segment equalizing basin through advanced oxidation desalination conjugation system, mixes with the landfill leachate in the pond and carries out subsequent processing, realizes the landfill leachate concentrate zero release. The patent is similar to the patent in that nanofiltration concentrated water is treated and then returns to the front end of the system. The difference lies in that: patent CN208265976U nanofiltration concentrate adopts oxidation desalination conjugation system, get back to the anterior segment after removing organic matter and salinity and realize getting rid of, nanofiltration concentrate only passes through advanced oxidation and becomes the micromolecule with the macromolecule organic oxidation that the nanofiltration membrane can hold back in this patent, biodegradable's organic matter, then directly get back to the front end, the nanofiltration membrane has specific requirement here, adopt NF270 or more compact nanofiltration membrane, one of effective separation hyperfiltration aquatic, divalent ion, hold back more organic matters on the one hand, be favorable to alleviating of rear end EDR unit membrane pollution, on the other hand enrichment sulfate ion, flow back to the front end, it uses sulfate reducing bacteria to strengthen the biological segment operation effect as the core to anticipate. In addition, although patent CN208265976U realizes full-flow treatment and zero emission of leachate, the problems exist: 1. the whole process of the system is anaerobic-two-stage AO-MBR-nanofiltration treatment, according to the process and the operation condition of a leachate station at the present stage, the deep treatment only adopts nanofiltration and is difficult to realize the discharge reaching the standard, and most salt ions cannot be intercepted by a nanofiltration membrane; 2. the conditions of large sludge discharge amount of a percolate treatment system, insufficient carbon source of a denitrification system and the like at the present stage cannot be improved.
In summary, the existing landfill leachate treatment process has the following disadvantages: the advanced treatment generates membrane concentrated solution, and the treatment of concentrated water becomes difficult; the biochemical system has large sludge yield and large treatment pressure; the carbon source of the biochemical system is insufficient, so that the total nitrogen of the system is difficult to control, the cost for adding the carbon source is high, and the effluent quality is unstable.
Disclosure of Invention
In order to solve the problems and current situations of large concentrated water amount, incapability of being consumed and difficult treatment in the landfill leachate treatment process in the prior art, a novel landfill leachate treatment system and a treatment process thereof are provided.
In order to achieve the purpose, the invention adopts the following technical scheme:
the utility model provides a novel landfill leachate processing system, is including the anaerobism unit, the denitrification pond that connect gradually, nitrify pond, ultrafiltration unit, receive and filter unit, electrodialysis unit, receive and filter the unit and pass through advanced oxidation unit and connect the anaerobism unit, the ultrafiltration unit passes through backflow pipeline and connects the denitrification pond.
As a further preferable scheme, the electrodialysis unit is externally connected with a low-temperature evaporation unit.
As a further preferred scheme, the anaerobic unit and the ultrafiltration unit are jointly connected with the sludge treatment unit.
A treatment process of a novel landfill leachate treatment system comprises the following steps:
the method comprises the following steps: the garbage percolate enters an anaerobic unit, organic carbon in the sewage is oxidized through a biological anaerobic sulfuric acid reduction process, organic matters in the sewage are removed, and then the garbage percolate enters a nitrification tank;
step two: in the nitrification tank, ammonia nitrogen forms nitrate NO under the action of nitrifying bacteria under the aeration condition 3 - The effluent flows back to the denitrification tank through the ultrafiltration unit in a cross flow manner;
step three: in the denitrification tank, NO 3 - As an electron acceptor, the nitrogen is generated by interaction with sulfide in the sewage generated by the anaerobic unit, so as to realize the autotrophic denitrification process, and the ultrafiltration effluent enters the ultrafiltration water generating tank and then enters the nanofiltration unit;
step four: in the nanofiltration unit, a nanofiltration membrane with a specific aperture is adopted, the molecular weight cutoff is required to be 100-300 daltons, macromolecular organic matters and macromolecular salts are intercepted to nanofiltration concentrated water, sulfate radicals are enriched, and the nanofiltration produced water is delivered to a nanofiltration water production tank;
step five: the advanced oxidation unit decomposes macromolecular organic matters in the nanofiltration concentrated water by using an advanced oxidation technology, removes the micromolecular organic matters by oxidation, and returns the produced water carrying a small amount of organic matters and sulfate radicals with higher concentration to the anaerobic unit;
step six: the electrodialysis unit is connected with the nanofiltration water production tank, salt is separated by using potential difference, the separation of calcium ions, magnesium ions, chloride ions and nitrate ions is realized, concentrated water is delivered to the concentrated water tank, and the produced water is discharged after reaching the standard.
As a further preferable scheme, the electrodialysis unit electric concentration water tank is connected to the low-temperature evaporation unit, inorganic salt is separated out in the evaporation crystallization process, and the leachate salt recovery is realized.
As a further preferable scheme, the sludge generated by the separation of the anaerobic unit and the ultrafiltration unit is dehydrated by a sludge filter press and then is transported out or is incinerated.
The purpose and advantage of this patent:
1. the invention provides a novel complete process for treating garbage leachate, which adopts a process of sulfuric acid reduction anaerobic system, nitrification and denitrification system, ultrafiltration, nanofiltration and electrodialysis, wherein effluent meets the reuse water standard, nanofiltration concentrated water generated in the process is subjected to advanced oxidation and then returns to the anaerobic system, and ED concentrated water is evaporated at low temperature and then is discharged after reaching the standard.
2. The innovation point of this patent is the combination of "sulphuric acid reduction type anaerobic system-autotrophic denitrification system" and nanofiltration technology, utilize the nanofiltration membrane of specific aperture to realize holding back and the enrichment of sulfate radical, sulfate radical ion returns to the biological section of front end along with the concentrate, realize on the one hand and receive the concentrated water absorption of straining, on the other hand effectively promotes biochemical system's sulfate radical ion concentration to the realization uses sulphur as the decarbonization denitrogenation process of medium, provides brand-new thinking for landfill leachate biological treatment process.
3. According to the process of sulfuric acid reduction anaerobic system, nitrification and denitrification system, ultrafiltration, nanofiltration and electrodialysis, sulfate radicals are intercepted and enriched by using the nanofiltration membrane with a specific aperture and flow back to the front end, conditions (SRB) are provided for growth of sulfate radical reducing bacteria in the anaerobic reactor, the sulfate radical reducing bacteria have the advantage of low sludge yield in decarburization, the denitrification unit performs autotrophic denitrification by using sulfides generated by the anaerobic unit, good denitrification can be realized without adding a carbon source for treatment of landfill leachate with unbalanced carbon-nitrogen ratio and the like, and the addition cost of a large amount of carbon source is saved.
4. The invention solves the difficulties of low concentration ratio, scaling and foaming in the treatment of percolate by a low-temperature evaporation process, firstly utilizes a nanofiltration system to greatly reduce organic matters and sulfate ions in the percolate, and effectively prevents core pain points of a subsequent advanced treatment unit in use: 1. the electrodialysis has serious organic pollution phenomenon in the treatment of the landfill leachate, and the nanofiltration unit is preposed to intercept most organic pollutants, thereby effectively reducing the risk of membrane pollution; 2. the evaporimeter has serious scale deposit, bubble scheduling problem in landfill leachate's processing of low temperature evaporation unit, in this patent technology, select for use specific aperture's nanofiltration membrane to intercept most organic matters effectively to separate different molecular weight's salt ion simultaneously, effectively separate sulfate ion and calcium magnesium ion, under the condition of low organic matter, low sulfate radical, the preliminary concentration of salt is realized to the rethread electrodialysis unit, evaporimeter scale deposit and foaming tendency greatly reduced promotes concentrated multiplying power by a wide margin.
5. Organic matters in the nanofiltration concentrated water are removed or smashed into organic matters with smaller molecules through advanced oxidation, the biodegradability of the organic matters is enhanced, and the organic matters return to the anaerobic unit to realize further removal of COD; the concentration of sulfate ions can reach hundreds or even thousands, the sulfate ions can effectively ensure the activity of sulfate reducing bacteria after returning to the anaerobic unit, and negative divalent sulfur generated by biochemical action can also effectively fix part of heavy metal ions, so that the fixation and sedimentation of the heavy metal ions are realized, and a system is removed along with sludge discharge.
The electrodialysis and low-temperature evaporation process is used for replacing a Reverse Osmosis (RO) and disc tube type reverse osmosis (DTRO) process which is commonly used at the present stage, the effluent quality reaches the standard and is discharged, the low-temperature evaporation process can flexibly utilize the surplus, waste heat, methane heating and the like, the operation pressure is greatly reduced, and the investment and the operation cost are reduced.
Drawings
FIG. 1 is a process flow diagram of the present invention.
Detailed Description
The invention is described in further detail below with reference to the figures and specific examples.
The garbage leachate treatment mostly adopts the treatment process of 'anaerobic treatment + AO + advanced treatment', and a series of membrane technologies are required to be utilized for advanced treatment after biochemical effluent is generated, so as to ensure that the hardness and the salinity in the sewage are removed, and ensure that the effluent quality reaches the standard. The landfill leachate treatment process at the present stage has a plurality of problems to be solved:
the biochemical unit is a means for effectively removing organic matters and ammonia nitrogen, has the characteristics of low investment and operation cost and the like, and has an irreplaceable position in a sewage treatment process. The existing biochemical unit process mostly adopts an anaerobic process and an AO process, so that the problems of insufficient carbon source, large sludge yield, incomplete treatment and the like exist, and particularly in the treatment of percolate, the carbon source addition caused by unbalanced carbon-nitrogen ratio is one of the main operation costs; some novel biochemical processes which can solve the problems, such as sulfate reducing bacteria and the like, can not be applied due to the restriction of the water quality condition of the percolate;
in the advanced treatment process, the actual engineering at the present stage mostly adopts the processes of ultrafiltration, nanofiltration and reverse osmosis, but the problem of producing a large amount of membrane concentrated solution exists, the membrane concentrated solution has the characteristics of high COD, high salinity, complex components and the like, the treatment and the consumption are difficult, and if the environment is seriously polluted due to improper treatment, the membrane concentrated solution becomes a pain point and a difficulty point of various refuse landfill plants or incineration plants. At present, according to the current situation, various concentrated water consumption processes, such as incineration, evaporation and the like, are derived, wherein the incineration process utilizes an incinerator of a waste incineration plant, but the concentrated water back-spraying incinerator has negative effects on the temperature and the like in the incineration process, components in the concentrated water, such as organic matter, inorganic salt and the like, can have the effects of coking, scaling and the like on equipment such as the incinerator and the like, and the process is only suitable for being applied to waste leachate of the incineration plant, and cannot realize the complete consumption of the concentrated water on the waste leachate without incineration conditions such as a landfill site or a transfer station and the like. The evaporation process is difficult to realize high-rate concentration due to the factors of high hardness, organic matters and the like of the landfill leachate.
The invention provides a novel landfill leachate full-flow treatment process, which realizes the enrichment of sulfate in the leachate through the model selection of a specific nanofiltration membrane, returns to the front section of a biological section and realizes the decarbonization and denitrogenation reaction by taking sulfur as a medium. The sulfate reduction type biological decarbonization of the anaerobic unit is realized by the enrichment of sulfate reducing bacteria in the anaerobic section, the autotrophic denitrification process is realized by utilizing sulfide and elemental sulfur generated by the anaerobic unit in the denitrification process, the sludge yield in the whole biochemical process is small, an external carbon source is not needed, and the biochemical effect is good. In addition, the negative divalent sulfur can react with partial heavy metal ions to generate sulfides in the conversion process, so that partial heavy metals are removed.
The combination of ultrafiltration and nanofiltration is utilized to carry out mud-water separation and further remove organic matters, the nanofiltration membrane adopts NF270 with small aperture to effectively separate macromolecular organic matters, the part of the organic matters are eliminated by advanced oxidative degradation, divalent anions are effectively separated, sulfate radicals and calcium ions are separated, and the risks of organic pollution and evaporator scaling and foaming of subsequent electrodialysis and low-temperature evaporation unit membranes are reduced. The separated sulfate ions return to the anaerobic unit to strengthen biochemical action, and the combination of ultrafiltration and nanofiltration does not need to discharge concentrated water.
The electrodialysis and low-temperature evaporation process is used for efficiently separating and recycling the salt in the leachate system, the electrodialysis and low-temperature evaporation process is used for replacing a Reverse Osmosis (RO) and disc tube type reverse osmosis (DTRO) process which is commonly used at the present stage, the effluent quality reaches the standard and is discharged, the low-temperature evaporation process can flexibly utilize the surplus, waste heat, methane heating and the like, the operation pressure is reduced, and the investment and operation cost are reduced.
The landfill leachate treatment process is as follows: as shown in fig. 1, in the first step, the landfill leachate first passes through a pretreatment unit to remove larger suspended solids; secondly, lifting the effluent of the previous unit by a water pump, feeding the effluent into a sulfuric acid reduction type anaerobic reactor, and decarbonizing by using the influent and sulfate ions in the reflux of the nanofiltration concentrated water to remove most organic matters; thirdly, overflowing sulfides carrying a large amount of electrons and ammonia nitrogen in the sewage into a nitrification and denitrification AO reactor together to perform nitrification and denitrification autotrophic nitrogen removal; fourthly, lifting the AO effluent to an external tubular ultrafiltration unit by a water pump for mud-water separation; fifthly, lifting the ultrafiltration product water by a water pump to enter a nanofiltration membrane treatment unit, removing part of macromolecular organic matters and sulfate ions, and obtaining nanofiltration product water and nanofiltration concentrated water; sixthly, the generated nanofiltration concentrated water enters an advanced oxidation pond for oxidation treatment and then returns to a front-end anaerobic unit; seventhly, conveying nanofiltration produced water to a nanofiltration water production tank, lifting the nanofiltration water production tank to an electrodialysis ED unit through a water pump, and performing salt separation to produce electrodialysis fresh water and electrodialysis concentrated water, wherein the electrodialysis fresh water is discharged after reaching standards; and eighthly, carrying a large amount of salt in the electrodialysis concentrated water to enter a low-temperature evaporation unit, and generating inorganic salt after low-temperature evaporation to realize salt recovery. The process has the advantages of good effluent quality of the whole process, no discharge of concentrated water, no need of an external carbon source for a biochemical unit, small sludge amount, stable operation of the whole system and low investment and operation cost.
And the garbage leachate enters from the water inlet end of the grid well and relatively large solid suspended matters in the garbage leachate are removed.
The water inlet of the anaerobic unit is connected with a water outlet end pipeline of the grille well, the anaerobic unit is used for enriching Sulfate Reducing Bacteria (SRB) to perform a decarburization process, sulfate radicals are used as electron acceptors in the decarburization process, and organic carbon in the sewage is oxidized through a biological anaerobic sulfate reduction process to remove organic matters. The anaerobic unit can adopt various forms such as a full-mixing anaerobic and upflow anaerobic sludge bed reactor, sulfate radicals carried in raw water and nanofiltration concentrated water subjected to advanced oxidation treatment provide energy for the growth and propagation process of sulfate reducing bacteria SRB, partial sulfur elements are settled in sludge in the forms of elemental sulfur, heavy metal sulfides and the like, and the sulfur elements are periodically discharged out of the treatment system along with the anaerobic unit.
A water inlet of the AO unit is connected with a water outlet end pipeline of the anaerobic unit, and ammonia nitrogen forms nitrate NO under the action of nitrobacteria in an O tank under the aeration condition 3 - The effluent is ultrafiltered and cross-flow refluxed to the tank A, and NO is added in the tank A 3 - As an electron acceptor, the nitrogen is generated by the interaction of the nitrogen and sulfide generated by the anaerobic unit, and the autotrophic denitrification process is realized.
And the water inlet of the ultrafiltration unit is connected with the water outlet of the AO pool through a pipeline and a water pump, and a small amount of pollutants are removed while the unit performs mud-water separation. The ultrafiltration is carried out by adopting external tubular ultrafiltration, the range of the molecular weight cut-off is 1000-40000 daltons, the ultrafiltration reflux ratio is set to be 8-10 times, the refluxed mud-water mixture returns to the A pool of the AO unit, and the ultrafiltration effluent is conveyed to an ultrafiltration water production pool.
A water inlet of the nanofiltration unit is connected with the ultrafiltration water production tank through a water pipe and a water pump, the nanofiltration unit adopts a small-aperture nanofiltration membrane, if NF270 is adopted, the range of the intercepted molecular weight is 100-300 daltons, and the design is thatThe water yield is 80%, and macromolecular organic substances (such as macromolecular humic acid) and macromolecular salts (such as SO) are intercepted 4 2- ) And the nanofiltration concentrated water is obtained, and the nanofiltration water is obtained and is sent to a nanofiltration water producing tank.
And the water inlet of the advanced oxidation unit is connected with the outlet end of the nanofiltration concentrated water, the advanced oxidation unit decomposes macromolecular organic matters in the nanofiltration concentrated water by using an advanced oxidation technology, oxidizes and removes the micromolecular organic matters, and the produced water returns to the anaerobic unit. The advanced oxidation unit can adopt one or centralized combination of various oxidation forms such as Fenton oxidation, ozone oxidation, ultrasonic oxidation and the like.
And the water inlet end of the electrodialysis unit is connected with a nanofiltration water production tank through a pipeline and a pump, salt is separated by using potential difference, the separation of calcium, magnesium, chloride ions, nitrate ions and other ions is realized, concentrated water is discharged to a concentrated water tank, and the produced water reaches the standard and is discharged. The electrodialysis unit adopts a homogeneous phase ion membrane form, controls the pH value of fresh water to be 5-6, the pH value of concentrated water to be 5-6 and the pH value of polar water to be 4-5, effectively avoids membrane surface deposition and pollution blockage by adopting a pole-reversing mode, and the pole-reversing period is 40-120 min/time.
Low Temperature Evaporation (LTE) unit, the low temperature evaporation unit is intake and is held and link to each other with pipeline and water pump with ED unit dense pond, utilizes the evaporation crystallization process to separate out inorganic salt, realizes that the filtration liquid salinity is retrieved. The low-temperature evaporation unit adopts a humidifying-dehumidifying evaporator, and waste heat, methane combustion heat of a refuse landfill and the like of a refuse incineration plant can be used as heat sources. The low-temperature evaporation unit is provided with a filter press and a dryer and is used for crystallizing and drying the mixed salt.
And the water inlet end of the sludge treatment unit is connected with the sludge discharge port of the anaerobic tank and the return sludge discharge port of the ultrafiltration unit through pipelines. The sludge treatment unit is provided with a sludge filter press. And carrying out outward transportation treatment or incineration treatment after sludge dehydration.
The patent is described below with reference to a specific example.
The invention treats the percolate of a certain refuse incineration plant, and the condition of the quality of the incoming water is as follows: COD 40000 mg/L, TDS 10000 mg/L, NH 3 N is 1800 mg/L, SS is 10000 mg/L.
The leachate passes through a pretreatment unit, the COD concentration of the effluent is 36000-38000 mg/L, the SS concentration is 6000-8000 mg/L, and then the effluent enters a sulfuric acid reduction type anaerobic unit. The anaerobic unit HRT 6d, the sludge concentration is kept at 20-30 g/L, COD of the anaerobic effluent is about 4000 mg/L, TDS and NH 3 The N concentration was essentially unchanged and the SS concentration was about 1800 mg/L. Anaerobic effluent enters a biochemical unit, enters an ultrafiltration unit for sludge-water separation after the nitrification and denitrification processes, wherein the interception molecular weight of the ultrafiltration membrane is 1000 daltons, the COD concentration of the effluent is about 400 mg/L, the ammonia nitrogen concentration is less than 20 mg/L, and the SS concentration is less than 10 mg/L. The ultrafiltration effluent enters a nanofiltration system, the recovery rate is set to be 80%, the COD concentration of the effluent is about 60 mg/L, the ammonia nitrogen concentration is less than 12 mg/L, the SS concentration is less than 5 mg/L, and the TDS concentration is about 9000 mg/L. And (2) the nanofiltration effluent enters an ED electrodialysis device, the electrodialysis is provided with an effluent discharge conductance of 4 us/cm, a concentrated water discharge conductance of 120 us/cm, the electrode inverting period is 1h, the COD concentration of the electrodialysis produced water is about 40 mg/L, the ammonia nitrogen concentration is less than 8 mg/L, the TDS concentration is less than 600 mg/L, the total hardness concentration is less than 200 mg/L, and the chloride ion concentration is less than 250 mg/L, so that the nanofiltration effluent reaches the water supplement standard of circulating cooling water (GB/T19923-2005) and is recycled in the factory.
The COD of the nanofiltration concentrated water generated in the process is about 350 mg/L, and the concentration of sulfate ions is 600-700 mg/L. The nanofiltration concentrated water enters a high-grade oxidation unit, the high-grade oxidation adopts an ozone oxidation mode in the case, the COD concentration of the effluent is less than 120 mg/L, the sulfate ion concentration is unchanged, and the effluent flows back to the anaerobic unit to carry out further decomposition of COD and biochemical process of sulfate ions.
The COD concentration of electrodialysis concentrated water generated in the process is about 130 mg/L, the TDS is about 60000 mg/L, the concentrated water sequentially enters a humidifying tower, a dehumidifying tower and a crystallizer, the evaporation temperature is 70-80 ℃, the concentration ratio is 5 times, mixed salt solid generated after crystallization is recovered, the crystallized salt is good in chroma and few in impurities, and the method has a certain recycling prospect.
The invention provides a novel landfill leachate full-process treatment process, effluent meets the nano-tube discharge standard, and has the advantages of high efficiency, low sludge yield, no additional carbon source and zero discharge in the whole process, and the key points of the process are as follows:
(1) the process for treating the landfill leachate is selected, in particular to the process combination of returning nanofiltration concentrated water to the front end of a biochemical section of a sulfuric acid reduction type anaerobic unit and a sulfur oxidation autotrophic denitrification unit for enriching sulfate radicals and the process selection of nanofiltration, electrodialysis and low-temperature evaporation for separating organic matters and sulfate radicals.
(2) The sequence and the flow of the landfill leachate treatment process. The invention utilizes the ingenious combination of various processes to realize the application of the decarbonization and denitrification process taking sulfur as a medium in the leachate, and simultaneously solves the technical difficulties of electrodialysis and low-temperature evaporation in the treatment application of the leachate.
(3) The parameter design of key units in the landfill leachate treatment process is particularly the model selection of nanofiltration membranes and the operation parameter design of each unit.
The patent provides a novel landfill leachate treatment process, and it is good to go out water quality of water, and the full flow zero release includes: the device comprises a pretreatment unit, a biochemical treatment unit and a deep treatment unit. Wherein the pretreatment unit is a grating well, and in order to get rid of the impurity in landfill leachate, the biochemical treatment unit includes anaerobism unit and AO unit, and in order to get rid of system COD and ammonia nitrogen, the advanced treatment unit includes ultrafiltration, nanofiltration, electrodialysis, advanced oxidation and low temperature evaporation unit, when further getting rid of COD, realizes the desorption and the recovery of salinity.
The above description is only a preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, and any simple modifications or equivalent substitutions of the technical solutions that can be obviously obtained by those skilled in the art within the technical scope of the present invention are within the scope of the present invention.

Claims (6)

1. The utility model provides a novel landfill leachate processing system which characterized in that: the device comprises an anaerobic unit, a denitrification tank, a nitrification tank, an ultrafiltration unit, a nanofiltration unit and an electrodialysis unit which are connected in sequence, wherein the nanofiltration unit is connected with the anaerobic unit through an advanced oxidation unit, and the ultrafiltration unit is connected with the denitrification tank through a return pipeline.
2. The novel landfill leachate treatment system of claim 1, wherein: the electrodialysis unit is externally connected with a low-temperature evaporation unit.
3. The novel landfill leachate treatment system of claim 1, wherein: the anaerobic unit and the ultrafiltration unit are connected with the sludge treatment unit together.
4. The treatment process of the novel landfill leachate treatment system according to any one of claims 1 to 3, comprising the steps of:
the method comprises the following steps: the garbage percolate enters an anaerobic unit, organic carbon in the sewage is oxidized through a biological anaerobic sulfuric acid reduction process, organic matters in the sewage are removed, and then the garbage percolate enters a nitrification tank;
step two: in the nitrification tank, ammonia nitrogen forms nitrate NO under the action of nitrifying bacteria under the aeration condition 3 - The effluent flows back to the denitrification tank through the ultrafiltration unit in a cross flow manner;
step three: in the denitrification tank, NO 3 - As an electron acceptor, the nitrogen is generated by interaction with sulfide in the sewage generated by the anaerobic unit, so that the autotrophic denitrification process is realized, and the ultrafiltration effluent flows to an ultrafiltration water generating tank and then enters a nanofiltration unit;
step four: in the nanofiltration unit, a nanofiltration membrane with a specific aperture is adopted, the molecular weight cutoff is required to be 100-300 daltons, macromolecular organic matters and macromolecular salts are intercepted to nanofiltration concentrated water, sulfate radicals are enriched, and the nanofiltration produced water is delivered to a nanofiltration water production tank;
step five: the advanced oxidation unit decomposes macromolecular organic matters in the nanofiltration concentrated water by using an advanced oxidation technology, oxidizes and removes the micromolecular organic matters, and the produced water carries a small amount of organic matters and sulfate radicals with higher concentration and returns to the anaerobic unit;
step six: the electrodialysis unit is connected with the nanofiltration water production tank, salt is separated by using potential difference, the separation of calcium ions, magnesium ions, chloride ions and nitrate ions is realized, concentrated water is delivered to the concentrated water tank, and the produced water is discharged after reaching the standard.
5. The treatment process of the novel landfill leachate treatment system according to claim 4, wherein: and the electrodialysis unit electric concentrated water tank is connected to the low-temperature evaporation unit, and inorganic salt is separated out in the evaporation and crystallization process, so that the recovery of the salt content of the leachate is realized.
6. The treatment process of the novel landfill leachate treatment system according to claim 4, wherein: and sludge generated by the separation of the anaerobic unit and the ultrafiltration unit is dehydrated by a sludge filter press and then is transported out or incinerated.
CN202210375636.9A 2022-04-11 2022-04-11 Novel landfill leachate treatment system and treatment process thereof Pending CN114890614A (en)

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CN116730554A (en) * 2023-07-20 2023-09-12 广州市适然环境工程技术有限公司 Advanced treatment process for leaching liquor of garbage incineration plant

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CN108373238A (en) * 2018-04-09 2018-08-07 广州华浩能源环保集团股份有限公司 A kind of landfill leachate concentration liquid zero-discharge treatment system and technique
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Publication number Priority date Publication date Assignee Title
WO2014037276A2 (en) * 2012-09-07 2014-03-13 Siemens Aktiengesellschaft Treatment of wastewater, especially mine water containing sulfate and/or heavy metal
CN205627588U (en) * 2016-04-14 2016-10-12 中国石油化工股份有限公司 Device of little biological desulfuration of closed circulation and recovery elemental sulfur
CN108275849A (en) * 2018-04-02 2018-07-13 南京万德斯环保科技股份有限公司 A kind of nanofiltration water outlet integrated conduct method
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CN116730554A (en) * 2023-07-20 2023-09-12 广州市适然环境工程技术有限公司 Advanced treatment process for leaching liquor of garbage incineration plant

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Application publication date: 20220812