CN114163063A - Leachate softening treatment device and application and process flow thereof - Google Patents

Leachate softening treatment device and application and process flow thereof Download PDF

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Publication number
CN114163063A
CN114163063A CN202111404769.6A CN202111404769A CN114163063A CN 114163063 A CN114163063 A CN 114163063A CN 202111404769 A CN202111404769 A CN 202111404769A CN 114163063 A CN114163063 A CN 114163063A
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China
Prior art keywords
reaction tank
softening
tank
pipeline
stage reaction
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CN202111404769.6A
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Chinese (zh)
Inventor
王立江
方丽娜
沈斌
徐李阳
冯华军
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Hangzhou Disc Filter Membrane Technology Co ltd
Zhejiang Gongshang University
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Hangzhou Disc Filter Membrane Technology Co ltd
Zhejiang Gongshang University
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Priority to CN202111404769.6A priority Critical patent/CN114163063A/en
Publication of CN114163063A publication Critical patent/CN114163063A/en
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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00—Multistage treatment of water, waste water or sewage
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/48—Treatment of water, waste water, or sewage with magnetic or electric fields
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F2001/007—Processes including a sedimentation step
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2301/00—General aspects of water treatment
    • C02F2301/08—Multistage treatments, e.g. repetition of the same process step under different conditions
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F5/00—Softening water; Preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F5/00—Softening water; Preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents
    • C02F5/02—Softening water by precipitation of the hardness
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F5/00—Softening water; Preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents
    • C02F5/02—Softening water by precipitation of the hardness
    • C02F5/06—Softening water by precipitation of the hardness using calcium compounds

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  • Life Sciences & Earth Sciences (AREA)
  • 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 relates to the technical field of landfill leachate treatment, in particular to a leachate softening treatment device, which comprises a primary reaction tank, a secondary reaction tank, a dosing device, an electromagnetic device, a pre-settling tank, a tubular softening membrane assembly and a settling tank, wherein the primary reaction tank is connected with the secondary reaction tank through a pipeline; the first-stage reaction tank is communicated with the second-stage reaction tank, and the dosing device is communicated with the first-stage reaction tank and the second-stage reaction tank; a reflux pipeline is arranged between the first-stage reaction tank and the second-stage reaction tank and is communicated with the first-stage reaction tank and the second-stage reaction tank, and an electromagnetic device is arranged on the reflux pipeline; the second-stage reaction tank is communicated with the pre-settling tank, the pre-settling tank is communicated with the tubular softening membrane component through a softening pipeline, the tubular softening membrane component comprises a clear water outlet and a intercepted water outlet, and an intercepted water backflow pipeline is arranged between the intercepted water outlet and the pre-settling tank; the pre-settling tank is communicated with the sedimentation tank through an overflow weir, and the bottom of the sedimentation tank is communicated with a sludge discharge pipeline. The invention can accelerate CaCO3The nucleation speed is increased, so that the supersaturation degree of the scaling substances is reduced, and the scaling on the wall is not easy.

Description

Leachate softening treatment device and application and process flow thereof
Technical Field
The invention relates to the technical field of landfill leachate treatment, in particular to a leachate softening treatment device and application and a process flow thereof.
Background
Along with the economic development and the urbanization acceleration of China, the garbage yield is increased gradually, the variety is more and more complex, and the garbage disposal problem is more and more severe. Meanwhile, a large amount of landfill leachate brought by the process of treating the garbage is difficult to effectively and reasonably solve. The current mainstream garbage leachate treatment method is an aerobic biological treatment technology and an anaerobic membrane biological technology, and the aerobic biological treatment technology is easy to cause high energy consumption and high carbon emission; the anaerobic membrane biological treatment technology has the characteristics of high efficiency and low consumption, and can realize energy recovery, however, the anaerobic membrane biological treatment technology is difficult to degrade high-hardness and high-alkalinity substances accompanied in organic wastewater, so that the subsequent anaerobic membrane bioreactor is often scaled, blocked and even collapsed, and the large-scale popularization and application of the anaerobic membrane biological treatment technology are restricted. How to reduce the hardness and alkalinity of the wastewater is the key for the development of anaerobic membrane biological treatment technology.
In the current landfill leachate treatment, the main softening method is a chemical treatment method and a physical treatment method. A common chemical treatment process is the medicated softening process. For example, patent CN210065322U discloses a pretreatment softening reaction device for batch treatment of desulfurization wastewater, which comprises a softening reaction tank, a stirring device, and a guide cylinder, wherein the upper end and the lower end of the guide cylinder are communicated and are positioned below the liquid level in the softening reaction tank, a radial bridge platform is arranged on the upper side of the softening reaction tank, the stirring device is fixed on the radial bridge platform, and the guide cylinder is positioned in the middle of the softening reaction tank and is coaxial; the stirring device comprises a driving motor and a stirring speed reducer which are mutually connected in a transmission way, the shaft of the stirring speed reducer is connected with a rotating rod which is coaxial with the softening reaction tank, the lower end shaft of the rotating rod is connected with a stirring paddle, and the stirring paddle is positioned at the lower part in the guide cylinder; an alkali dosing pipe, a sodium carbonate dosing pipe, a water inlet pipe and a water outlet pipe are arranged on the softening reaction tank, and the guide cylinder is positioned between the overflow pipe and the water outlet pipe. The softening device solves the problem of frequent chemical dosage adjustment caused by the fluctuation of continuous treatment softening equipment along with the water quality, and ensures desulfurizationThe effect of softening the wastewater pretreatment. However, the drawbacks of the medicated softening method are mainly shown in that: the chemical softening method usually focuses on the removal rate of hardness ions in water, and neglects the influence of the particle size distribution, crystal composition and crystal form of the generated precipitate on a subsequent filtering membrane. The particle with the pore size close to that of the membrane can block the filtering membrane, reduce the membrane flux and influence the softened effluent; at the same time, Ca2CO3The crystals have various morphologies, but eventually calcite is formed, which is a dense hard scale that is difficult to remove.
Common physical treatment methods include membrane separation methods, electromagnetic methods. The biggest problem of membrane separation is membrane fouling. The existing electromagnetic method generally has long treatment time and slow effect. For example, patent CN204958539U discloses an electromagnetic hard water softening device, which is characterized by comprising: 12V direct current power supply, multivibrator and frequency regulating circuit, electromagnetic field forming circuit; the multivibrator is composed of a time-base circuit IC1, a resistor R1, a linear potentiometer RP and a capacitor C1, wherein the model of the time-base circuit IC1 is NE 555. The softening device makes small calcium carbonate crystals in water coagulate and form large crystals under the action of electromagnetic field, so that the deposition of calcium carbonate is effectively reduced and the coagulation of water scale on the walls of water pipes, four walls and bottom of boiler is avoided. The deposition of calcium carbonate can be effectively reduced in water passing through a magnetic field or an electric field. However, it is difficult to expand the application range further because of its long processing period.
Therefore, it is desirable to provide a leachate softener that can treat leachate quickly and efficiently, reduce the hardness and alkalinity of the leachate, and reduce scaling.
Disclosure of Invention
In order to solve the problems, the invention provides a leachate softening device, which is based on a variable frequency electromagnetic field softening mode and combined with a chemical softening technology, influences the formation process of precipitate particles in leachate, changes the particle size distribution and crystal form of the precipitate, relieves the reduction of membrane flux and is convenient for cleaning subsequent scale.
In order to achieve the purpose, the technical scheme of the invention is as follows:
a leachate softening device comprises a primary reaction tank, a secondary reaction tank, a dosing device, an electromagnetic device, a pre-settling tank, a tubular softening membrane assembly and a settling tank; a water inlet pipeline is arranged on one side of the primary reaction tank, the primary reaction tank is communicated with the secondary reaction tank, and the dosing device is communicated with the primary reaction tank and the secondary reaction tank through dosing pipelines; a return pipeline communicated with the first-stage reaction tank and the second-stage reaction tank is arranged between the first-stage reaction tank and the second-stage reaction tank, and the electromagnetic device is arranged on the return pipeline; the secondary reaction tank is communicated with the pre-settling tank, the pre-settling tank is communicated with the tubular softening membrane component through a softening pipeline, the tubular softening membrane component comprises a clear water outlet and a intercepted water outlet, and a intercepted water backflow pipeline is arranged between the intercepted water outlet and the pre-settling tank; the pre-settling tank is communicated with the settling tank through an overflow weir, and the bottom of the settling tank is communicated with a sludge discharge pipeline.
Further, a medicament and a stirrer are arranged in the dosing device, and the medicament comprises a lime solution with the concentration of 10% and a NaOH solution with the concentration of 30%.
Further, the dosing mode of the dosing device is that lime solution with the concentration of 10% is added into the first-stage reaction tank until the pH value of the first-stage reaction tank is 11.5, and NaOH solution with the concentration of 30% is added into the second-stage reaction tank until the pH value of the second-stage reaction tank is 12.
Furthermore, a first stirrer is arranged in the first-stage reaction tank, and a second stirrer is arranged in the second-stage reaction tank.
Further, the electromagnetic device comprises a pulse signal generator and a solenoid, the return pipe passes through the inside of the spiral pipe, and the solenoid comprises a coil, and the number of turns of the coil is 20-40.
Furthermore, the waveform emitted by the pulse signal generator is square wave, and the frequency range is 1-20 KHz.
The backwashing device comprises a backwashing tank, the backwashing tank is communicated with the outlet end of the tubular softening membrane component through a backwashing pipeline, a backwashing water pump and a first valve are arranged on the backwashing pipeline, the water inlet end of the tubular softening membrane component is connected with a backwashing water outlet pipeline, and a second valve is arranged on the backwashing water outlet pipeline.
Furthermore, the working time of the back washing device is 15s, and the interval between two back washing is 15 min; and a citric acid solution with the concentration of 2% is filled in the backwashing tank.
Further, set up the intake pump on the intake pipe, set up the backwash pump on the backflow pipeline, set up the dosing pump on the dosing pipeline, set up the circulating pump on the softening pipeline, set up the sludge discharge pump on the sludge discharge pipeline.
Further, the tubular softening membrane component comprises a plurality of tubular softening membranes, the filtering pore size of each softening membrane is 50nm, and the diameter of each softening membrane is 12.7 mm.
Based on the leachate softening device, the process flow of the invention is as follows:
s1, introducing the leachate to be treated into a primary reaction tank through a water inlet pipeline, adding a lime solution with the concentration of 10% into the primary reaction tank according to the ion concentration of the leachate, and starting a first stirrer;
s2, enabling the mud-water mixture in the first-stage reaction tank to enter a second-stage reaction tank, adding a 30% NaOH solution into the second-stage reaction tank, and starting a second stirrer, wherein at the moment, more precipitates are generated in the second-stage reaction tank;
s3, enabling the muddy water mixture in the secondary reaction tank to enter an electromagnetic device through a backflow pipeline for further softening, and enabling the softened muddy water mixture to flow back to the primary reaction tank;
s4, the fully softened mud-water mixture enters a pre-settling tank, and crystals of the scaling substances are gathered in the pre-settling tank;
s5, enabling the liquid in the pre-settling tank to enter a tubular softening membrane module through a softening pipeline for filtering, discharging the filtered clear water from a clear water outlet, and refluxing the high-concentration muddy water into the pre-settling tank again;
s6, overflowing high-concentration sludge water in the preliminary sedimentation tank into a sedimentation tank for sludge-water separation, and discharging sludge deposited at the bottom of the sedimentation tank through a sludge discharge pipeline;
and S7, performing backwashing once every 15min of operation of the tubular softening membrane module, wherein the backwashing time is 15S.
Compared with the prior art, the invention has the beneficial effects that:
1. on the basis of chemical softening, a backflow pipeline is arranged between a secondary reaction tank and a primary reaction tank, an electromagnetic device is arranged on the backflow pipeline, the leachate in the softening process is magnetized by utilizing an electromagnetic field generated by the electromagnetic device, so that water molecules generate a resonance phenomenon, hydrogen bonds among the water molecules are broken, the water molecule associations in the solution are decomposed into monomer or smaller association water molecules, or the bond length and the bonding angle of the water molecules are increased, the surface tension and the viscosity of the solution water are reduced, the surface Gibbs free energy required by crystal nucleus formation is reduced, the lattice Gibbs free energy is also reduced, and therefore the CaCO in the leachate can be accelerated3The formation and dehydration process of the hydration of the crystal nucleus precursor accelerates CaCO3The crystal nucleus is generated at a high speed, so that more micro crystals are generated, the supersaturation degree of the scaling substances is reduced, the stability of the solution is enhanced, and the scaling on the wall of the device is not easy.
2. According to the dosing mode obtained by the experiment, the PH value of the softening process can be accurately controlled, the effect of softening the medicine is fully exerted, and the softening efficiency of the percolate is greatly improved.
3. The backwash liquid provided by the invention adopts the citric acid solution with the concentration of 2%, and compared with other backwash liquids, the backwash liquid can improve backwash efficiency and reduce corrosion to the softened film, so that the service life of the softened film is prolonged.
Drawings
FIG. 1 is a schematic diagram of the system of the present invention.
Description of reference numerals:
1-a water inlet pump; 2-a dosing device; 3-a dosing pump; 4-a first-stage reaction tank; 5-a secondary reaction tank; 6-a preliminary sedimentation tank; 7-reflux pump; 8-a solenoid; 9-a pulse signal generator; 10-a circulating pump; 11-tubular softening membrane module; 12-a sedimentation tank; 13-a sludge pump; 14-a backwash tank; 15-backwashing the water pump; 16-a first valve; 17-second valve.
Detailed Description
The technical solutions of the present invention will be described in detail with reference to the accompanying drawings, and it is obvious that the described embodiments are not all embodiments of the present invention, and all other embodiments obtained by those skilled in the art without any inventive work belong to the protection scope of the present invention. It should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.
As shown in fig. 1, the invention provides a leachate softening device, which comprises a primary reaction tank 4, a secondary reaction tank 5, a dosing device 2, an electromagnetic device, a pre-settling tank 6, a tubular softening membrane assembly 11 and a settling tank 12; 4 one side of one-level reaction tank sets up the inlet channel, sets up intake pump 1 on the inlet channel, and filtration liquid passes through the inlet channel and during 1 entering one-level reaction tank 4 of inlet pump, set up first agitator in the one-level reaction tank 4, add the reaction of medicine and filtration liquid with higher speed. An adjacent wall is arranged between the primary reaction tank 4 and the secondary reaction tank 5, the primary reaction tank 4 is communicated with the secondary reaction tank 5 by opening holes on the adjacent wall, and a second stirrer is arranged in the secondary reaction tank 5.
The dosing device 2 is respectively communicated with the primary reaction tank 4 and the secondary reaction tank 5 through dosing pipelines, and a dosing pump 3 is arranged on the dosing pipelines; a stirrer is arranged in the dosing device 2, a medicament is contained in the dosing device 2, the medicament comprises a lime solution with the concentration of 10% and a NaOH solution with the concentration of 30%, the lime solution is added into the primary reaction tank 4 through a dosing pipeline, and the temporary hardness and alkalinity of the percolate are removed; NaOH solution is added into the secondary reaction tank 5 through a dosing pipeline, and hardness and alkalinity which are not removed in the primary reaction tank 4 are removed.
A reflux pipeline communicated with the primary reaction tank 4 and the secondary reaction tank 5 is arranged between the primary reaction tank and the secondary reaction tank, and the electromagnetic device and a reflux pump 7 are arranged on the reflux pipeline; the electromagnetic device comprises a pulse signal generator 9 and a solenoid 8, wherein the pulse signal generator 9 sends out variable-frequency high-speed pulses, the sweep frequency range is 1-20KHz, the resonance of different water molecules under different water quality conditions can be met, the waveforms of the pulses are square, the voltage signals of the square waves are changed more violently, the generated electromagnetic field can bring greater disturbance to ions and molecules in water, and the better magnetization effect is achieved; the solenoid 8 comprises an internal round tube and a coil wound around the round tube, the round tube is made of a plastic tube with the outer diameter of 100mm and the inner diameter of 90mm, the coil is wound by a copper enameled wire with the diameter of 0.6mm, and the number of turns is 20-40.
The percolate without hardness and alkalinity in the secondary reaction tank 5 contains more CaCO3、MgCO3、CaCl2Wait the scale deposit molecule, percolate at this moment gets into in solenoid 8 through the return line, percolate receives the effect of electromagnetic field, the surface tension and the viscosity decline of scale deposit molecule, so the required surface gibbs free energy of crystal nucleus formation reduces, lattice gibbs free energy also reduces, consequently, formation and the dehydration process of scale deposit molecule crystal nucleus precursor hydration in the percolate can be accelerated, accelerate the formation of scale deposit crystal nucleus, thereby generate more small crystal, reduce the supersaturation of scale deposit material, solution stability reinforcing, make the scale deposit material be difficult for on the moltening film, and then reduce the production of scale deposit, slow down the reduction process of moltening film flux.
The secondary reaction tank 5 and the pre-settling tank 6 have adjacent walls, the secondary reaction tank 5 is communicated with the pre-settling tank 6 by opening holes on the adjacent walls, the pre-settling tank 6 is communicated with the tubular softening membrane module 11 through a softening pipeline, a circulating pump 10 is arranged on the softening pipeline, and the circulating pump 10 pumps percolate in the pre-settling tank 6 into the tubular softening membrane module 11 for filtering. The tubular softening membrane assembly 11 comprises a clear water outlet and a trapped water outlet, a trapped water backflow pipeline is arranged between the trapped water outlet and the pre-settling tank 6, namely, after being filtered by the tubular softening membrane assembly 11, the trapped water containing trapped matters flows back to the pre-settling tank 6 for filtration again; the preliminary sedimentation tank 6 communicates through the overflow weir sedimentation tank 12, the mud pipeline is arranged in the bottom intercommunication of sedimentation tank 12, sets up sludge pump 13 on the mud pipeline, carries out mud-water separation in the filtration liquid entering sedimentation tank 12 in the preliminary sedimentation tank 6, and the mud of sedimentation tank bottom is discharged from the mud pipeline through sludge pump 13.
Wherein, tubular softening membrane subassembly 11 includes a plurality of tubular membranes of connecting in parallel, and the quantity of tubular membrane can be decided according to sewage treatment scale, and the material of tubular membrane is polyvinylidene fluoride, and polyvinylidene fluoride has the characteristic of fluororesin and general resin concurrently, except that having resistant chemical corrosion, high temperature resistant, oxidation-resistant, weatherability, resistant ray radiation, still has special properties such as piezoelectricity, dielectricity and pyroelectricity nature. The filtering aperture of the tubular membrane is 50nm, the diameter of the membrane tube of the tubular membrane is 12.7mm, the tubular membrane adopts a cross flow filtering mode, when the percolate passes through the tubular membrane, the percolate flows through the inner surface of the membrane tube under the driving of pressure, and intercepted substances (suspended solid particles) are taken out of the membrane tube by concentrated solution and cannot be accumulated on the surface of the membrane to cause pollution and blockage. In the cross-flow filtration mode, the feed liquid flows through the surface of the filter membrane in a tangential direction, so that liquid on the surface of the membrane forms a turbulent flow state, particulate matters are prevented from being accumulated into a cake layer, in addition, the high-concentration suspended solid flows out of the tubular membrane along with the concentrated liquid under the continuous scouring action, the high-concentration suspended solid flows back to the pre-sedimentation tank from the intercepted water outlet, and water molecules passing through the filter holes are converged into clean water to flow out of the clean water outlet.
The outlet end of the tubular softening membrane component 11 is connected with a back washing device, the back washing device comprises a back washing tank 14, the back washing tank 14 is communicated with the outlet end of the tubular softening membrane component 11 through a back washing pipeline, a back washing water pump 15 and a first valve 16 are arranged on the back washing pipeline, the water inlet end of the tubular softening membrane component 11 is connected with a back washing water outlet pipeline, and a second valve 17 is arranged on the back washing water outlet pipeline. The working time of one back washing of the back washing device is 15s, and the interval between the two back washing is 15 min; the backwash tank 14 is filled with a 2% citric acid solution.
The process flow of the invention is as follows:
s1, introducing the leachate to be treated into the primary reaction tank 4 through a water inlet pipeline, adding a lime solution with the concentration of 10% into the primary reaction tank 4 according to the ion concentration of the leachate, and starting a first stirrer;
s2, enabling the mud-water mixture in the first-stage reaction tank 4 to enter a second-stage reaction tank 5, adding a 30% NaOH solution into the second-stage reaction tank 5, and starting a second stirrer, wherein more precipitates are generated in the second-stage reaction tank 5;
s3, enabling the muddy water mixture in the secondary reaction tank 5 to enter an electromagnetic device through a backflow pipeline for further softening, and enabling the softened muddy water mixture to flow back to the primary reaction tank 4;
s4, the fully softened mud-water mixture enters the preliminary sedimentation tank 6, and crystals of the scaling substances are gathered in the preliminary sedimentation tank 6;
s5, enabling the liquid in the pre-settling tank 6 to enter a tubular softening membrane module 11 through a softening pipeline for filtering, discharging filtered clear water from a clear water outlet, and refluxing high-concentration muddy water to the pre-settling tank 6 again;
s6, overflowing high-concentration sludge and water in the pre-settling tank 6 into the settling tank 12 for sludge and water separation, and discharging sludge deposited at the bottom of the settling tank 12 through a sludge discharge pipeline;
and S7, performing backwashing once every 15min when the tubular softening membrane assembly 11 works, wherein the backwashing time is 15S.
Example one
The environmental temperature of the leachate softening device is 25 ℃, the inflow rate is 15L/h, the total hydraulic retention time is 4h, the calcium ion concentration is 222mg/L, the magnesium ion concentration is 584mg/L, the carbonate concentration is 220mg/L, and the bicarbonate concentration is 1.7 multiplied by 103mg/L, total hardness of 2.7X 103mg/L, total alkalinity of 2.2X 103mg/L, initial membrane flux 500L/m2H. After the leachate softening device disclosed by the invention is adopted for softening, in a clear water outlet of the tubular softening membrane component 11, the concentration of calcium ions in outlet water is 5.4mg/L, the concentration of magnesium ions is 8.5mg/L, the total hardness is 48.9mg/L, the total alkalinity is 63.1mg/L, the removal rate of the hardness reaches 98.18%, and the removal rate of the alkalinity reaches 97.13%; after the working time of 40h, the membrane flux is 486L/m2H. Wherein, the total hardness and the total alkalinity are both CaCO3And (6) counting.
Example two
By adopting the leachate softening device, the ambient temperature is 25 ℃, the inflow rate is 10L/h, the total hydraulic retention time is 3h, the calcium ion concentration is 126mg/L, the magnesium ion concentration is 366mg/L, the carbonate concentration is 277mg/L, and the bicarbonate concentration is 1.9 multiplied by 103mg/L, total hardness of 2.0X 103mg/L, total alkalinity of 2.3X 103mg/L, initial membrane flux 500L/m2H. After the leachate softening device disclosed by the invention is adopted for softening, in a clear water outlet of the tubular softening membrane component 11, the concentration of calcium ions in outlet water is 1.3mg/L, the concentration of magnesium ions is 2.1mg/L, the total hardness is 18.7mg/L, the total alkalinity is 22.6mg/L, the removal rate of the hardness reaches 99.06%, and the removal rate of the alkalinity reaches 99.02%; the membrane flux is 490L/m after the working time of 36h2H. Wherein, the total hardness and the total alkalinity are both CaCO3And (6) counting.
Although the present invention has been described in detail with reference to examples, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the present invention.

Claims (10)

1. A leachate softening device is characterized in that: comprises a first-stage reaction tank, a second-stage reaction tank, a dosing device, an electromagnetic device, a pre-settling tank, a tubular softening membrane component and a settling tank; a water inlet pipeline is arranged on one side of the primary reaction tank, the primary reaction tank is communicated with the secondary reaction tank, and the dosing device is communicated with the primary reaction tank and the secondary reaction tank through dosing pipelines; a return pipeline communicated with the first-stage reaction tank and the second-stage reaction tank is arranged between the first-stage reaction tank and the second-stage reaction tank, and the electromagnetic device is arranged on the return pipeline; the secondary reaction tank is communicated with the pre-settling tank, the pre-settling tank is communicated with the tubular softening membrane component through a softening pipeline, the tubular softening membrane component comprises a clear water outlet and a intercepted water outlet, and a intercepted water backflow pipeline is arranged between the intercepted water outlet and the pre-settling tank; the pre-settling tank is communicated with the settling tank through an overflow weir, and the bottom of the settling tank is communicated with a sludge discharge pipeline.
2. The leachate softening apparatus of claim 1, wherein: and a medicament and a stirrer are arranged in the dosing device, and the medicament comprises a lime solution with the concentration of 10% and a NaOH solution with the concentration of 30%.
3. The leachate softening apparatus of claim 2, wherein: the dosing mode of the dosing device is that lime solution with the concentration of 10% is added into the first-stage reaction tank, the PH value of the first-stage reaction tank is adjusted to 11.5, NaOH solution with the concentration of 30% is added into the second-stage reaction tank, and the PH value of the second-stage reaction tank is adjusted to 12.
4. The leachate softening apparatus of claim 1, wherein: a first stirrer is arranged in the first-stage reaction tank, and a second stirrer is arranged in the second-stage reaction tank.
5. The leachate softening apparatus of claim 1, wherein: the electromagnetic device comprises a pulse signal generator and a solenoid, the return pipeline penetrates through the inside of the spiral pipe, and the solenoid comprises a coil, and the number of turns of the coil is 20-40; the waveform emitted by the pulse signal generator is square wave, and the frequency range is 1-20 KHz.
6. The leachate softening apparatus of claim 1, wherein: the backwashing device comprises a tubular softening membrane component, a backwashing water pump and a first valve are arranged on the backwashing pipeline, the water inlet end of the tubular softening membrane component is connected with a backwashing water outlet pipeline, and a second valve is arranged on the backwashing water outlet pipeline.
7. The leachate softening apparatus of claim 6, wherein: the working time of the back washing device is 15s, and the interval between two back washing is 15 min; and a citric acid solution with the concentration of 2% is filled in the backwashing tank.
8. The leachate softening apparatus of claim 1, wherein: the improved chemical adding device is characterized in that a water inlet pump is arranged on the water inlet pipeline, a reflux pump is arranged on the reflux pipeline, a chemical adding pump is arranged on the chemical adding pipeline, a circulating pump is arranged on the softening pipeline, and a sludge discharge pump is arranged on the sludge discharge pipeline.
9. Use of the percolate softening device according to any one of claims 1 to 8 in the treatment of waste water.
10. A leachate softening method using the leachate softening apparatus of any of claims 1 to 8, wherein: the method comprises the following steps:
s1, introducing the leachate to be treated into a primary reaction tank through a water inlet pipeline, adding a lime solution with the concentration of 10% into the primary reaction tank according to the ion concentration of the leachate, and starting a first stirrer;
s2, enabling the mud-water mixture in the first-stage reaction tank to enter a second-stage reaction tank, adding a 30% NaOH solution into the second-stage reaction tank, and starting a second stirrer, wherein at the moment, more precipitates are generated in the second-stage reaction tank;
s3, enabling the muddy water mixture in the secondary reaction tank to enter an electromagnetic device through a backflow pipeline for further softening, and enabling the softened muddy water mixture to flow back to the primary reaction tank;
s4, the fully softened mud-water mixture enters a pre-settling tank, and crystals of the scaling substances are gathered in the pre-settling tank;
s5, enabling the liquid in the pre-settling tank to enter a tubular softening membrane module through a softening pipeline for filtering, discharging the filtered clear water from a clear water outlet, and refluxing the high-concentration muddy water into the pre-settling tank again;
s6, overflowing high-concentration sludge water in the preliminary sedimentation tank into a sedimentation tank for sludge-water separation, and discharging sludge deposited at the bottom of the sedimentation tank through a sludge discharge pipeline;
and S7, performing backwashing once every 15min of operation of the tubular softening membrane module, wherein the backwashing time is 15S.
CN202111404769.6A 2021-11-24 2021-11-24 Leachate softening treatment device and application and process flow thereof Pending CN114163063A (en)

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