Treatment equipment suitable for aged leachate

Abstract

The utility model discloses treatment equipment suitable for aged leachate. The treatment equipment comprises a pretreatment system, a DTRO (Disk Tubular Reverse Osmosis) system, an immersion combustion evaporation system, an ammonia separation membrane system and a contact oxidation system which are connected in sequence, the inlet end of the pretreatment system is connected with a lifting pump, and the aged leachate is guided into the pretreatment system through the lifting pump; the pretreatment system consists of a high-density sedimentation tank, a lime dosing device, a flocculant dosing device and an acid-base regulation dosing device; the high-density sedimentation tank is communicated with the clarification water tank; the lime dosing device, the flocculant dosing device and the acid-base adjusting dosing device are mounted on the edge of the high-density sedimentation tank; the system disclosed by the utility model has the advantages that the problems that the total nitrogen exceeds the standard, the residual concentrated solution is difficult to treat and the like in the traditional treatment of the aged leachate are solved, high-concentration ammonia energy in the aged leachate can be recycled, the treatment cost of the whole system is reduced, and an effective way is provided for the treatment of the aged leachate.

Description

A treatment device for leachate from aging plants Technical Field

[0001] This utility model relates to a water treatment device, specifically a device suitable for treating leachate from elderly people, and belongs to the field of water treatment equipment. Background Technology

[0002] Currently, many large and medium-sized municipal solid waste landfills in my country have been in use for more than 10 years and are considered aging landfills. Aging landfills have large amounts of leachate, and the water quality characteristics are as follows: (1) Low concentration of organic pollutants: COD < 5000 mg / L and BOD5 < 2000 mg / L in most aging landfills. (2) High ammonia nitrogen content: up to 2000-3500 mg / L, causing a serious imbalance in the carbon-nitrogen ratio, and the high concentration of ammonia ions inhibits biological treatment. (3) High salt content: because early landfills did not have leachate treatment systems, the leachate was mostly treated by reinjection, resulting in high salt content in the leachate of aging landfills, with conductivity reaching tens of thousands of ppm or more, which inhibits the activity of microorganisms and affects the treatment effect. Moreover, the salt content increases with the length of time the landfill has been in use.

[0003] Currently, the common process for treating leachate from aging landfills in China is "biochemical treatment + NF / RO", with biochemical treatment mainly using "AO + MBR" membrane bioreactors. From numerous engineering cases, it's clear that treating leachate from aging landfills presents several problems, primarily in the following aspects: (1) Excessive total nitrogen in effluent: Since the biochemical reaction relies heavily on carbon source addition, insufficient carbon source addition during on-site operation often leads to poor microbial activity within the system, resulting in poor treatment effects and effluent total nitrogen often exceeding 100 mg / L. (2) Inability to treat remaining high-concentration concentrate: In traditional aging leachate treatment processes, salt is mainly retained through nanofiltration and reverse osmosis membranes, resulting in a remaining 35-50% membrane concentrate. Currently, there is no good way to dispose of or treat this high-concentration membrane concentrate, creating even greater treatment challenges. Due to problems such as excessive total nitrogen in effluent and the inability to treat remaining high-concentration concentrate, the treatment of leachate from aging landfills has become a major industry challenge. Summary of the Invention

[0004] The purpose of this invention is to design a treatment device suitable for aged leachate, which solves the problems of excessive total nitrogen and difficulty in treating residual concentrate in traditional aged leachate treatment. Furthermore, the high concentration of ammonia in aged leachate can be recovered and utilized, reducing the overall system treatment cost and providing an effective way to treat aged leachate.

[0005] The technical solution of this utility model is as follows:

[0006] A treatment device for leachate from aging plants includes a pretreatment system, a DTRO system, an immersion combustion evaporation system, an ammonia separation membrane system, and a contact oxidation system connected in sequence.

[0007] Aged leachate is introduced into the pretreatment system via a lift pump. The inlet of the pretreatment system is connected to the lift pump, which guides the aged leachate into the pretreatment system. The pretreatment system consists of a high-density sedimentation tank, a lime dosing device, a flocculant dosing device, and an acid-base adjustment dosing device. The high-density sedimentation tank is connected to a clarification tank. The lime dosing device, flocculant dosing device, and acid-base adjustment dosing device are installed at the edge of the high-density sedimentation tank.

[0008] The purpose of the pretreatment system is to add lime, coagulants, and coagulant aids to the water, causing particles that are difficult to settle to aggregate and form colloids. These colloids then combine with impurities in the water to form larger flocs. These flocs have strong adsorption capacity, adsorbing not only suspended solids but also some bacteria and dissolved substances. Through adsorption, the flocs increase in volume and settle. The effluent after coagulation and sedimentation passes through a clarification tank and enters the next stage of the treatment system.

[0009] The DTRO system is a disc tube reverse osmosis system, including an integrated unit, a cleaning device, and a chemical dosing device. A DTRO feed pump is installed at the inlet of the DTRO system, pumping the aged leachate from the pretreatment system into the DTRO system. After passing through the pretreatment system, the aged leachate is pumped into the integrated unit by the DTRO feed pump. A security filter is installed at the front end of the integrated unit to prevent large particles from entering the membrane. The pressure is then further increased by a high-pressure pump to meet the DTRO filtration requirements. The permeate from the DTRO system meets discharge standards, and the remaining concentrate enters the submerged combustion evaporation system.

[0010] The submerged combustion evaporation system includes a submerged combustion evaporator. The bottom of the submerged combustion evaporator is equipped with a sludge tank and a residual liquid water pump. The bottom of the submerged combustion evaporator is connected to the top plate of the sludge tank via a pipe, and the bottom of the sludge tank is connected to the inlet of the residual liquid water pump. The top of the sludge tank is connected to the top of a preheater via a steam pipe, and the top of the preheater is connected to the submerged combustion evaporator via a preheated leachate pipe. The bottom of the preheater is equipped with a leachate inlet, and condensate outlets and non-condensable gas outlets on both sides, respectively discharging condensate and non-condensable gas. The top of the submerged combustion evaporator is also equipped with a biogas or landfill gas inlet and a combustion air inlet.

[0011] The sludge tank of the submerged combustion evaporation system is also connected to the residual liquid tank. The outlet of the residual liquid tank is connected to the supernatant tank. The slag outlet of the residual liquid tank is connected to the slag dewatering system. The outlet of the slag dewatering system is connected to the supernatant tank.

[0012] The ammonia separation membrane system is a PTFE ammonia nitrogen removal membrane. A hydrophobic PTFE hollow fiber microporous membrane separates the ammonia-nitrogen-containing condensate from the acid absorbent. The ammonia nitrogen in the condensate dissociates into gaseous NH3, which then passes through the micropores in the PTFE membrane wall and reacts with the acid absorbent on the other side. The reacted solution is used as ammonium sulfate fertilizer. The condensate after ammonia nitrogen removal is deammonium-treated water, which enters the next system for further processing.

[0013] The contact oxidation system is a contact oxidation tank that purifies wastewater by using microbial biofilm formation through packing material placed inside the tank. The contact oxidation system includes a tank body with an inlet and an outlet. A water distributor is installed at the inlet to distribute the water volume. Packing material with a biofilm attached is placed inside the tank. The contact oxidation system also includes an aeration device to supply oxygen to the system.

[0014] The outlet of the pool is equipped with an MBR membrane device, which is a membrane bioreactor (MBR). The MBR membrane device is equipped with a membrane module, which removes biodegradable organic pollutants from the deammoniation water through activated sludge. The MBR membrane module forcibly retains the activated sludge and most of the suspended solids in the bioreactor, thereby achieving solid-liquid separation between the purified water and the activated sludge.

[0015] The deammonia-removed water enters the contact oxidation system through a pipeline, and then enters the packing zone through a water distributor. After being oxygenated by the aeration device, the deammonia-removed water flows through the packing at a certain flow rate and comes into contact with the biofilm. The biofilm and the suspended activated sludge work together to further purify the deammonia-removed water, and then it is discharged after being filtered through an MBR membrane to meet the standards.

[0016] The beneficial effects of this utility model are as follows:

[0017] (1) Total nitrogen in effluent is guaranteed. Total nitrogen can be effectively removed through pretreatment and DTRO membrane filtration, and there is a contact oxidation system as a subsequent guarantee. The total nitrogen in the concentrate is effectively removed by crystallization and ammonia separation membrane filtration, and further denitrification treatment through the contact oxidation system can ensure that the total nitrogen in the effluent meets the discharge standards.

[0018] (2) Ammonia nitrogen is recovered and reused. A special ammonia separation membrane is used to remove ammonia from the water and the ammonia is recovered and reused through acid absorption. If the ammonia recovery rate is 20%, then about 0.5 kg of ammonia is recovered from treating 1 ton of leachate (based on an influent ammonia nitrogen of 2500 mg / L), which can turn waste into treasure.

[0019] (2) Solving the problem of residual concentrate. This utility model is designed for near-zero discharge of leachate from aging landfills, producing no residual concentrate and only a small amount of salt mud, thus solving the problem of leachate treatment in aging landfills.

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] Figure 1 is a process flow diagram of a treatment device for leachate from aging plants according to an embodiment of the present invention;

[0022] Figure 2 is a schematic diagram of the preprocessing system structure according to an embodiment of the present invention;

[0023] Figure 3 is a schematic diagram of the DTRO system structure according to an embodiment of the present invention;

[0024] Figure 4 is a schematic diagram of the immersion combustion evaporation structure of an embodiment of this utility model;

[0025] Figure 5 is a schematic diagram of the ammonia separation membrane structure according to an embodiment of the present invention;

[0026] Figure 6 is a schematic diagram of the contact oxidation system structure according to an embodiment of the present invention. Detailed Implementation

[0027] The preferred embodiments of this utility model are described below. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the scope of this utility model. Embodiments

[0028] As shown in Figures 1-6, a treatment device suitable for leachate from aging plants includes a pretreatment system 1, a DTRO system 2, an immersion combustion evaporation system 4, an ammonia separation membrane system 3, and a contact oxidation system 5 connected in sequence.

[0029] Aged leachate is pumped into pretreatment system 1 via a lift pump. The inlet of pretreatment system 1 is connected to the lift pump, which guides the aged leachate into the pretreatment system 1. Pretreatment system 1 consists of a high-density sedimentation tank 11, a lime dosing device, a flocculant dosing device, and an acid-base adjustment dosing device. The high-density sedimentation tank 11 is connected to a clarification tank 12. The lime dosing device, flocculant dosing device, and acid-base adjustment dosing device are installed at the edge of the high-density sedimentation tank 11 and are all existing devices. The purpose of the pretreatment system is to add lime, coagulant, and coagulant aid to the water, causing particles that are difficult to settle in the water to aggregate and form colloids, which then combine with impurities in the water to form larger flocs. The flocs have strong adsorption capacity, adsorbing not only suspended solids but also some bacteria and dissolved substances. Through adsorption, the flocs increase in volume and sink. The effluent after coagulation and sedimentation reaction passes through clarification tank 12 and enters the next stage of treatment system, as shown in Figure 2.

[0030] The DTRO system 2 is a disc tube reverse osmosis system, including an integrated unit 21, a cleaning device 22, and a chemical dosing device 23, as shown in Figure 3. A DTRO feed pump is installed at the inlet of the DTRO system, pumping the aged leachate from the pretreatment system into the DTRO system. After passing through the pretreatment system, the aged leachate enters the integrated unit 21 via the DTRO feed pump. A security filter 24 is installed at the front end of the integrated unit 22 to prevent large particles from entering the membrane. The pressure is then further increased by a high-pressure pump 25 to meet the DTRO filtration requirements. The permeate from the DTRO system meets discharge standards, and the remaining concentrate enters the submerged combustion evaporation system.

[0031] The submerged combustion evaporation system, as shown in Figure 4, includes a submerged combustion evaporator 41 (patent number: ZL200410042792.5). The bottom of the submerged combustion evaporator 41 is equipped with a sludge tank 42 and a residual liquid water pump 43. The bottom of the submerged combustion evaporator is connected to the top plate of the sludge tank via a pipe. The bottom of the sludge tank 42 is connected to the inlet of the residual liquid water pump. The top of the sludge tank is connected to the top of a preheater 45 via a steam pipe 44. The top of the preheater 45 is connected to the submerged combustion evaporator 41 via a preheated leachate pipe 46. The bottom of the preheater 45 is equipped with a leachate inlet 47, and condensate outlets and non-condensable gas outlets are respectively provided on both sides to discharge condensate and non-condensable gas. The top of the submerged combustion evaporator 41 is also equipped with a biogas or landfill gas inlet 48 and a combustion air inlet 49.

[0032] The sludge tank 42 of the submerged combustion evaporation system 4 is also connected to the residual liquid tank 6. The outlet of the residual liquid tank 6 is connected to the supernatant tank 7. The slag outlet of the residual liquid tank 6 is connected to the slag dewatering system 8. The liquid outlet of the slag dewatering system 8 is connected to the supernatant tank 7.

[0033] The ammonia separation membrane system 3 is a PTFE ammonia nitrogen removal membrane. A hydrophobic PTFE hollow fiber microporous membrane separates the ammonia-nitrogen-containing condensate from the acid absorbent. The ammonia nitrogen in the condensate dissociates into gaseous NH3, which then passes through the micropores on the PTFE membrane wall and reacts with the acid absorbent on the other side. The reacted solution is then used as ammonium sulfate fertilizer. The condensate after ammonia nitrogen removal is deammonium-treated water, which enters the next system for further processing.

[0034] The contact oxidation system 5 is a contact oxidation tank that purifies wastewater by using biofilm action of microorganisms through packing material placed inside the tank. The contact oxidation system includes a tank body 51 with an inlet and an outlet. A water distributor 52 is installed at the inlet to distribute the water volume. Packing material 53 with a biofilm attached is placed inside the tank. The contact oxidation system 5 also includes an aeration device 54 for supplying oxygen to the system.

[0035] The outlet of the pool 51 is equipped with an MBR membrane device, which is a membrane bioreactor (MBR). The MBR membrane device is equipped with a membrane module 55, which removes biodegradable organic pollutants from the deammoniation water through activated sludge. The MBR membrane module forcibly retains the activated sludge and most of the suspended solids in the bioreactor, thereby achieving solid-liquid separation between the purified water and the activated sludge.

[0036] The deammonia-removed water enters the contact oxidation system through a pipeline, and then enters the packing zone through a water distributor. After being oxygenated by the aeration device, the deammonia-removed water flows through the packing at a certain flow rate and comes into contact with the biofilm. The biofilm and the suspended activated sludge work together to further purify the deammonia-removed water, and then it is discharged after being filtered through an MBR membrane to meet the standards.

Claims

1. A treatment device suitable for leachate from aged plants, characterized in that: It includes a pretreatment system, a DTRO system, an immersion combustion evaporation system, an ammonia separation membrane system, and a contact oxidation system connected in sequence; the inlet of the pretreatment system is connected to a booster pump, through which aged leachate is introduced into the pretreatment system; The pretreatment system consists of a high-density sedimentation tank, a lime dosing device, a flocculant dosing device, and an acid-base adjustment dosing device. The high-density sedimentation tank is connected to a clarification tank. The lime dosing device, flocculant dosing device, and acid-base adjustment dosing device are installed at the edge of the high-density sedimentation tank.

2. The equipment for treating leachate from aged plants according to claim 1, characterized in that: The DTRO system is a disc tube reverse osmosis system, including a complete integrated unit, a cleaning device, and a chemical dosing device; the inlet of the DTRO system is equipped with a DTRO inlet pump, which pumps the aged leachate after passing through the pretreatment system into the DTRO system; a security filter is installed at the front end of the complete integrated unit.

3. The equipment for treating leachate from aged plants according to claim 1, characterized in that: The submerged combustion evaporation system includes a submerged combustion evaporator. The bottom of the submerged combustion evaporator is equipped with a sludge tank and a residual liquid water pump. The bottom of the submerged combustion evaporator is connected to the top plate of the sludge tank through a pipe. The bottom of the sludge tank is connected to the inlet of the residual liquid water pump. The top of the sludge tank is connected to the top of the preheater through a steam pipe. The top of the preheater is connected to the submerged combustion evaporator through a preheated leachate pipe. The bottom of the preheater is equipped with a leachate inlet, and the two sides are equipped with a condensate outlet and a non-condensable gas outlet, respectively, to discharge condensate and non-condensable gas. The top of the submerged combustion evaporator is also equipped with a biogas or landfill gas inlet and a combustion air inlet.

4. The equipment for treating leachate from aged plants according to claim 3, characterized in that: The sludge tank of the submerged combustion evaporation system is also connected to the residual liquid tank. The outlet of the residual liquid tank is connected to the supernatant tank. The slag outlet of the residual liquid tank is connected to the slag dewatering system. The outlet of the slag dewatering system is connected to the supernatant tank.

5. The equipment for treating leachate from aged plants according to claim 1, characterized in that: The ammonia separation membrane system is a PTFE ammonia nitrogen removal membrane.

6. The equipment for treating leachate from aged plants according to claim 1, characterized in that: The contact oxidation system is a contact oxidation tank, which includes a tank body with an inlet and an outlet. A water distributor is installed at the inlet to distribute the water volume. The tank body contains packing material with a biofilm attached to it. The contact oxidation system also includes an aeration device for supplying oxygen to the contact oxidation system.

7. The equipment for treating leachate from aged plants according to claim 6, characterized in that: The outlet of the pool is equipped with an MBR membrane device, which is a membrane bioreactor (MBR) and has membrane modules.

Images