CN111470729A - Garbage leachate treatment system and method for garbage incineration power plant - Google Patents

Abstract

The invention discloses a waste leachate treatment system and a method of a waste incineration power plant, wherein the waste leachate treatment system comprises a primary sedimentation tank, a primary anaerobic reactor, a secondary anaerobic reactor, an anaerobic sedimentation tank, a softening reactor, a tubular microfiltration membrane, an ammonia still and a built-in MBR; the primary sedimentation tank, the primary anaerobic reactor, the secondary anaerobic reactor, the anaerobic sedimentation tank, the softening reactor, the tubular microfiltration membrane, the ammonia still and the built-in MBR are sequentially connected according to the circulation treatment direction of the garbage leachate. The invention realizes the standard discharge of the waste leachate by sequentially carrying out primary sedimentation pretreatment, primary anaerobic treatment, secondary anaerobic treatment, hardness-removing softening treatment, an ammonia still and low-load built-in MBR treatment on the waste leachate.

Description

Landfill leachate treatment system and method for waste incineration power plant

technical field

The invention relates to the technical field of wastewater treatment, in particular to a system and method for treating landfill leachate in a waste incineration power plant.

Background technique

At this stage, garbage power plants have sprung up across the country. Waste incineration power generation will definitely be the mainstream technology of waste treatment in the future, and will also receive strong support from the state. Landfill leachate is an inescapable topic in waste incineration power generation technology. A process system with lower investment cost, lower operating cost and stable operation is the goal that the industry is constantly pursuing.

During the process of storage, transfer, transportation and stacking of garbage, various metabolites and water are generated due to anaerobic fermentation, organic matter decomposition, rainwater leaching, etc., forming a highly complex organic wastewater with high concentration - landfill leachate.

The composition of landfill leachate is complex, the COD concentration is generally around 40000-80000mg/l, the ammonia nitrogen concentration is generally around 1000-2500mg/l, and the salt content is also high. It is difficult to treat it to the required level by using traditional biochemical treatment technology. Emission Standards. At present, the mainstream process of leachate treatment in waste incineration power plants is mainly: pretreatment + anaerobic + external MBR (nitrification / denitrification + ultrafiltration system) + NF + RO. This process route is a relatively mature set of processes in the industry, but it also has some disadvantages, such as high investment, high operating cost, large area, and high water treatment cost per ton. The membrane concentrate requires co-processing by power plants. According to the operating experience, the A/O system in the external MBR system has many equipments such as aeration fans, jet pumps, reflux pumps, defoaming pumps, etc. In the whole process flow, this system consumes the highest proportion of electricity, and nitrification/denitrification Operating electricity consumption accounts for about 60%-80% of the overall electricity consumption, and its cost accounts for about 50% of the cost of water treatment per ton. At the same time, after the NF and RO systems are put into operation, about 30% of the membrane concentrate is produced. Due to the characteristics of high organic concentration, high salt content, strong scaling, and complex pollutant components in the membrane concentrate, it is quite difficult to treat the concentrate. There is no mature economical and reasonable treatment process at home and abroad.

Therefore, in order to reduce the production of membrane concentrate, and at the same time reduce the investment cost and ton water treatment cost, it is necessary to improve the treatment process to replace the external MBR system and the advanced membrane treatment system.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a landfill leachate treatment system and a landfill leachate treatment method for a waste incineration power plant with reduced cost and good treatment effect.

The technical solution adopted by the present invention to solve the technical problem is: to provide a landfill leachate treatment system of a waste incineration power plant, which includes a primary sedimentation tank connected to the landfill leachate, and the landfill leachate is subjected to mesothermal anaerobic treatment in sequence. First-level anaerobic reactor and second-level anaerobic reactor for treatment, anaerobic sedimentation tank, softening reactor for softening anaerobic treatment of landfill leachate, and filtration treatment for softened landfill leachate The tubular microfiltration membrane, the ammonia distillation tower for the ammonia distillation treatment of the clear liquid obtained by filtration, the built-in MBR for the biochemical treatment and filtration treatment of the clear liquid after the ammonia distillation;

The primary sedimentation tank, the primary anaerobic reactor, the secondary anaerobic reactor, the anaerobic sedimentation tank, the softening reactor, the tubular microfiltration membrane, the ammonia distillation tower and the built-in MBR are processed according to the flow of the landfill leachate. Connect in sequence.

Preferably, the landfill leachate treatment system further comprises a basket filter and a self-cleaning filter arranged at the front end of the primary settling tank for filtering the landfill leachate.

Preferably, the filtration precision of the basket filter is 5mm or 10mm; the filtration precision of the self-cleaning filter is 1mm or 2mm.

Preferably, the landfill leachate treatment system further comprises a conditioning tank for homogeneous and uniform treatment of the landfill leachate; the conditioning tank is connected between the primary sedimentation tank and the primary anaerobic reactor.

Preferably, the anaerobic reaction temperatures of the primary anaerobic reactor and the secondary anaerobic reactor are both 35°C to 38°C.

Preferably, the microfiltration membrane pore size of the tubular microfiltration membrane is 0.1-0.5 μm.

Preferably, the landfill leachate treatment system further comprises a sludge tank and a sludge dewatering treatment device connected to the sludge tank; the primary sedimentation tank, the primary anaerobic reactor, the secondary anaerobic reactor, The anaerobic sedimentation tank and the built-in MBR are respectively connected to the sludge tank.

Preferably, the landfill leachate treatment system further includes an emergency nanofiltration device connected to the water outlet end of the built-in MBR to filter the effluent of the built-in MBR.

The present invention also provides a method for treating landfill leachate in a waste incineration power plant, comprising the following steps:

S1. The landfill leachate enters the primary sedimentation tank for preliminary sedimentation treatment;

S2. The landfill leachate after preliminary precipitation treatment is transported to the first-stage anaerobic reactor for mesophilic anaerobic treatment, so that the insoluble organic matter in the landfill leachate is decomposed into small molecular substances;

S3. Transporting the landfill leachate after the mesothermal anaerobic treatment to the secondary anaerobic reactor for secondary anaerobic treatment to remove the organic matter therein;

S4. Transport the landfill leachate after the secondary anaerobic treatment to the anaerobic sedimentation tank for anaerobic sedimentation treatment;

S5, the effluent of the anaerobic sedimentation tank is sent to the softening reactor and calcium hydroxide is added for softening treatment, and the amount of calcium hydroxide added is adjusted according to the pH value measured online;

S6. Transport the softened landfill leachate to a tubular microfiltration membrane, and filter to remove suspended solids and organic microorganisms in the landfill leachate;

S7, the clear liquid obtained after the filtration is transported to the ammonia distillation tower to carry out the ammonia distillation process, and the ammonia nitrogen in the clear liquid is removed;

S8. The effluent of the ammonia distillation tower is sent to the built-in MBR, and through denitrification and nitrification, the biochemical organic matter therein is biochemically removed and biological denitrification is carried out.

Preferably, in step S1, before the landfill leachate enters the primary settling tank, it is filtered through the basket filter and the self-cleaning filter in sequence.

Preferably, in step S2, the landfill leachate after preliminary precipitation treatment is first transported to the conditioning tank for homogeneous and homogeneous treatment, and then sent to the primary anaerobic reactor.

Preferably, the landfill leachate treatment method further comprises the following steps:

S9, filtering the effluent of the built-in MBR through an emergency nanofiltration device to reduce the organic matter index of the effluent.

The landfill leachate treatment system and method of the present invention, by sequentially subjecting the landfill leachate to primary sedimentation pretreatment, first-stage anaerobic treatment, second-stage anaerobic treatment, de-hardening softening treatment, ammonia distillation tower and low-load built-in MBR treatment is adopted to realize the discharge of landfill leachate up to the standard.

The present invention has the following advantages:

(1), reduce the investment cost per ton of water for the entire process;

(2), reduce the cost of water treatment per ton of landfill leachate treatment industry;

(3) Since most of the organic matter is removed in anaerobic treatment, and the low-load built-in MBR system or membrane advanced treatment system is used to reduce the amount of sludge;

(4) The residence time of the low-load built-in MBR biochemical tank is shortened, the required reactor volume is reduced, and the investment cost such as floor space and civil construction is saved;

(5) When the built-in MBR is used, the dependence of the system on the membrane advanced treatment system is reduced, and no membrane concentrate is generated;

(6) Make full use of the ammonia nitrogen removal effect of the ammonia distillation tower.

In addition, through the setting of the emergency nanofiltration device, the effluent of the built-in MBR is further filtered to ensure that the organic matter index of the effluent meets the discharge standard and minimize the generation of membrane concentrate.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and embodiments, in which:

FIG. 1 is a connection block diagram of a landfill leachate treatment system according to an embodiment of the present invention.

Detailed ways

In order to have a clearer understanding of the technical features, objects and effects of the present invention, the specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

The landfill leachate treatment system and method of the waste incineration power plant of the present invention are used for treating the landfill leachate to make it meet the discharge standard.

As shown in FIG. 1 , the landfill leachate treatment system of a waste incineration power plant according to an embodiment of the present invention includes a primary sedimentation tank 1, a first-stage anaerobic reactor 3, a primary sedimentation tank 1, a first-stage anaerobic reactor 3, Secondary anaerobic reactor 4, anaerobic sedimentation tank 5, softening reactor 6, tubular microfiltration membrane 7, ammonia distillation tower 8 and built-in MBR (membrane bioreactor) 9.

Among them, the primary sedimentation tank 1 is connected to landfill leachate, so that the landfill leachate is pretreated for preliminary precipitation therein. The first-level anaerobic reactor 3 and the second-level anaerobic reactor 4 sequentially perform mesophilic anaerobic treatment on the landfill leachate, the first-level anaerobic reactor 3 performs the first-level anaerobic reaction, and the second-level anaerobic reactor 4 performs the first-level anaerobic reaction. In the secondary anaerobic treatment, the anaerobic sedimentation tank 5 is used for anaerobic sedimentation of the landfill leachate after the anaerobic treatment, so as to reduce the sludge concentration in the effluent. The softening reactor 6 softens the anaerobic-treated landfill leachate to remove most of the hardness. The tubular microfiltration membrane 7 filters the softened landfill leachate to remove suspended solids and organic microorganisms therein. The ammonia distillation tower 8 performs ammonia distillation on the clear liquid obtained by filtration to remove ammonia nitrogen therein. The built-in MBR 9 performs biochemical treatment and filtration treatment on the clear liquid after ammonia distillation, so that the landfill leachate can meet the discharge standard.

The landfill leachate treatment system of the present invention further includes a basket filter 101 and a self-cleaning filter 102. According to the flow direction of the landfill leachate, the basket filter 101 and the self-cleaning filter 102 are arranged in the primary sedimentation tank 1. At the front end, the landfill leachate is filtered, and the filtered landfill leachate enters the primary sedimentation tank 1 for preliminary precipitation to remove larger particulate matter and some suspended solids in the landfill leachate; the bottom of the primary sedimentation tank 1 The sludge formed by sedimentation can be discharged by the power pump.

Alternatively, the filtration precision of the basket filter 101 is 5mm or 10mm; the filtration precision of the self-cleaning filter 102 is 1mm or 2mm.

In order to stabilize the water quality and quantity of the landfill leachate entering the subsequent treatment units, the landfill leachate treatment system of the present invention further includes a conditioning tank 2 for homogeneous and homogeneous treatment of the landfill leachate. The conditioning tank 2 is connected between the primary sedimentation tank 1 and the primary anaerobic reactor 3 .

The primary anaerobic reactor 3 and the secondary anaerobic reactor 4 realize two-stage anaerobic treatment of landfill leachate. Among them, in the primary anaerobic reactor 3, it is carried out in a medium temperature anaerobic environment, and 35°C-38°C is selected as the medium temperature anaerobic reaction temperature. After mesophilic anaerobic treatment, insoluble organic pollutants in landfill leachate are first decomposed into soluble macromolecular substances, then decomposed into small molecular organic acids, and finally decomposed into carbon dioxide, methane, water, ammonia nitrogen, hydrogen sulfide, Phosphate, inorganic salts and other small molecular substances to achieve the removal of pollutants. The landfill leachate after the primary anaerobic treatment enters the secondary anaerobic reactor 4 to continue the anaerobic reaction, and the anaerobic reaction temperature is selected from 35°C to 38°C to further remove the organic matter therein.

In the above-mentioned two-stage anaerobic treatment, the landfill leachate in the anaerobic environment, through the action of anaerobic microorganisms, decomposes most of the organic pollutants into small molecular substances, reducing COD and BOD. At the same time, the anaerobic reactor also has a certain removal rate for hardness, and the removal rate can reach about 70%. The removal of hardness greatly reduces the dosage of the subsequent treatment unit.

In the above-mentioned two-stage anaerobic treatment, the hydraulic retention time of the second-stage anaerobic reactor 4 is shorter than that of the first-stage anaerobic reactor 3 . The primary anaerobic reactor 3 and the secondary anaerobic reactor 4 may adopt a UASB reactor or an IC reactor. In addition, the biogas generated in the above-mentioned anaerobic treatment can be collected in the gas storage tank, and transported by pipeline to the incinerator of the power plant for incineration, and an emergency flare is set at the same time.

The effluent from the secondary anaerobic reactor 4 enters the anaerobic sedimentation tank 5 (closed), where anaerobic precipitation is carried out, mainly to avoid excessive sludge concentration in the anaerobic effluent, which affects the subsequent treatment process. The sludge formed by sedimentation and accumulation at the bottom of the anaerobic sedimentation tank 5 can be discharged by a power pump.

The anaerobic sedimentation tank 5 has a built-in center cylinder, which forms the form of water inflow around the center, and the bottom of the anaerobic sedimentation tank 5 is set in the form of a sludge hopper, which is convenient for sludge discharge.

The inlet end of the softening reactor 6 is connected to the outlet end of the anaerobic sedimentation tank 5 and connected to the effluent of the anaerobic sedimentation tank 5 to soften the anaerobic treated landfill leachate to remove most of the calcium. During the softening treatment, calcium hydroxide (slaked lime) can be put into the softening reactor 6 through the automatic dosing device, and the landfill leachate reacts with calcium hydroxide for coagulation and precipitation to remove most of the hardness in the landfill leachate. The input amount of calcium hydroxide is adjusted according to the pH value of the landfill leachate, and the automatic dosing device can adjust the input amount of calcium hydroxide according to the pH value of the landfill leachate, etc., and adjust the pH value in the softening reactor 6 to 11 -12. The pH of the softening reactor 6 is monitored online by a pH meter 61 .

The inlet end of the tubular microfiltration membrane 7 is connected to the effluent end of the softening reactor 6, and is connected to the effluent of the softening reactor 6, and the softened landfill leachate is filtered to remove the suspended solids and organic microorganisms, and further separated. , Clarify landfill leachate.

The microfiltration membrane pore size of the tubular microfiltration membrane 7 can be selected from 0.1-0.5 μm.

The effluent end of the tubular microfiltration membrane 7 is connected to an ammonia distillation tower 8, and the clear liquid obtained after filtration is transported to the ammonia distillation tower 8 for ammonia distillation treatment to remove ammonia nitrogen and part of volatile COD.

The ammonia nitrogen in the supernatant mostly exists in the state of ammonia ions (NH4+) and free ammonia ( _NH3 ) and maintains a balance, and the equilibrium relationship between the two is affected by the pH value. When the pH value is 7, the ammonia nitrogen mostly exists in the state of NH4+, and when the pH value is about 11, 90% of the ammonia nitrogen exists in the form of _NH3 , and free ammonia ( _NH3 ) is easy to escape from the water. In this embodiment, the ammonia distillation tower 8 adopts a blast ammonia stripping tower to promote the escape of ammonia from the clear liquid, and the removal rate of ammonia nitrogen by the ammonia distillation tower 8 can reach more than 95%. In order to avoid secondary pollution caused by the escaping ammonia gas, the escaping ammonia gas is recovered by pipeline and pumped to the denitrification system of the power plant.

The effluent of the ammonia distillation tower 8 is sent to the built-in MBR 9. After denitrification and nitrification, the biochemical organic matter in it is biochemically removed and biological denitrification is carried out, so that the final effluent reaches the "Standards for Pollution Control of Domestic Waste Landfills" (GB 16889). -2008), to achieve emission standards.

In this embodiment, the built-in MBR 9 includes a denitrification tank 91 , a nitrification tank 92 and a built-in ultrafiltration membrane device 93 which are connected in sequence. During operation, the mixed liquid in the nitrification tank 92 is returned to the denitrification tank 91, so that the denitrifying bacteria have enough NO ^3- as an electron acceptor, thereby increasing the denitrification rate. The microbial cells in the built-in MBR 9 are separated from the water through the built-in ultrafiltration membrane device 93 to ensure that suspended matter, microorganisms and suspended matter related to CODCr are safely trapped in the built-in ultrafiltration membrane device 93, so that the hydraulic retention time and The sludge residence time is truly separated. The excess sludge produced by the built-in ultrafiltration membrane device 93 is regularly discharged into the sludge tank, and the effluent is discharged up to the standard.

The ultrafiltration membrane in the built-in ultrafiltration membrane device 93 can be a built-in submerged plate membrane.

Further, as required, the landfill leachate treatment system of the present invention further includes a sludge tank 10 and a sludge dewatering treatment device 11 connected to the sludge tank 10 . The primary sedimentation tank 1, the primary anaerobic reactor 3, the secondary anaerobic reactor 4, the anaerobic sedimentation tank 5 and the built-in MBR9 are respectively connected to the sludge tank 10, and the sludge and other sediments accumulated in each of them can pass the pump And so on to the sludge tank 10. The sludge and other sediments stored in the sludge tank 10 can be further transported to the sludge dewatering treatment device 11 for dehydration treatment, the formed dry sludge can be sent to the power plant for incineration, and the dewatered liquid can be returned to the denitrification tank for treatment.

According to needs, the landfill leachate treatment system of the present invention also includes an emergency nanofiltration device 12, which is connected to the water outlet of the built-in MBR9 to filter the effluent of the built-in MBR9, reduce the organic matter index of the effluent, and ensure that the effluent meets the discharge standard .

The emergency nanofiltration device 12 is specifically connected to the water outlet of the built-in ultrafiltration membrane device 93 . The pore size of the nanofiltration membrane of the emergency nanofiltration device is 1-10 nm.

In a small number of cases, the effluent organic matter of the built-in MBR 9 may exceed the standard. At this time, the emergency nanofiltration device 12 is activated to ensure that the effluent is discharged up to the standard. As an option for the emergency nanofiltration device 12, when the organic matter index of the effluent of the built-in MBR9 meets the relevant standards, the emergency nanofiltration device 12 may not be activated.

The landfill leachate treatment method of the waste incineration power plant of the present invention can be realized by the above-mentioned treatment system. Referring to FIG. 1 , the treatment method may include the following steps:

S1. The landfill leachate enters the primary sedimentation tank 1 for preliminary sedimentation treatment.

Preliminary precipitation is used as a pretreatment step to remove precipitable substances. The sludge formed by precipitation and accumulation at the bottom of the primary sedimentation tank 1 can be discharged to the sludge tank 10 through a power pump.

Alternatively, in this embodiment, before the landfill leachate enters the primary settling tank 1, it is filtered first, for example, it passes through the basket filter 101 and the self-cleaning filter 102 in sequence to filter out larger particles in the landfill leachate. Substances and some suspended solids.

S2. Transport the landfill leachate after the preliminary precipitation treatment to the first-stage anaerobic reactor 3 for medium-temperature anaerobic treatment, so that the insoluble organic matter in the landfill leachate is decomposed into small molecular substances, and the density of the landfill leachate is reduced. COD and BOD.

Among them, the temperature of the mesophilic anaerobic treatment is 35°C-38°C.

After mesophilic anaerobic treatment, insoluble organic pollutants in landfill leachate are first decomposed into soluble macromolecular substances, then decomposed into small molecular organic acids, and finally decomposed into carbon dioxide, methane, water, ammonia nitrogen, hydrogen sulfide, Small molecular substances such as phosphates and inorganic salts.

Before entering the first-level anaerobic reactor 3, the landfill leachate is subjected to homogeneous and uniform treatment to ensure that the water quality and quantity of the landfill leachate entering the subsequent treatment units are stable. Homogeneous and homogeneous treatment can be realized in the conditioning tank 2 , and the landfill leachate after preliminary precipitation treatment is first transported to the conditioning tank 2 , and then sent to the primary anaerobic reactor 3 .

S3. The landfill leachate after the mesophilic anaerobic treatment is transported to the secondary anaerobic reactor 4 for secondary anaerobic treatment to remove the organic matter therein.

In the above-mentioned two-stage anaerobic treatment, the landfill leachate in the anaerobic environment, through the action of anaerobic microorganisms, decomposes most of the organic pollutants into small molecular substances, reducing COD and BOD. At the same time, the anaerobic reactor also has a certain removal rate for hardness, and the removal rate can reach about 70%. The removal of hardness greatly reduces the dosage of the subsequent treatment unit.

In the above-mentioned two-stage anaerobic treatment, the hydraulic retention time of the second-stage anaerobic reactor 4 is shorter than that of the first-stage anaerobic reactor 3 . The primary anaerobic reactor 3 and the secondary anaerobic reactor 4 may adopt a UASB reactor or an IC reactor. In addition, the biogas generated in the above-mentioned anaerobic treatment can be collected in the gas storage tank, and transported by pipeline to the incinerator of the power plant for incineration, and an emergency flare is set at the same time.

The sludge formed by precipitation and accumulation at the bottom of the primary anaerobic reactor 3 and the secondary anaerobic reactor 4 can be discharged to the sludge tank 10 through a power pump.

S4. The landfill leachate after the secondary anaerobic treatment is transported to the anaerobic sedimentation tank 5 for anaerobic sedimentation treatment.

The anaerobic sedimentation tank 5 is mainly for the landfill leachate after the secondary anaerobic treatment to stay and settle in it, so as to avoid the high concentration of the anaerobic effluent sludge and affect the subsequent treatment process. The sludge formed by sedimentation and accumulation at the bottom of the anaerobic sedimentation tank 5 can be discharged to the sludge tank 10 through a power pump.

In this embodiment, the anaerobic sedimentation tank 5 has a built-in center cylinder to form a form of water inflow around the center, and the bottom of the anaerobic sedimentation tank 5 is set in the form of a sludge hopper, which is convenient for discharging sludge, and the sludge can be discharged to the sludge tank 10 .

S5, the effluent of the anaerobic sedimentation tank 5 is sent to the softening reactor 6 and calcium hydroxide is added for softening treatment, and the amount of calcium hydroxide added is adjusted according to the pH value measured online.

During the softening treatment, calcium hydroxide (slaked lime) can be put into the softening reactor 6 through the automatic dosing device, and the landfill leachate reacts with calcium hydroxide for coagulation and precipitation to remove most of the hardness in the landfill leachate. The input amount of calcium hydroxide is adjusted according to the pH value of the landfill leachate, and the automatic dosing device can adjust the input amount of calcium hydroxide according to the pH value of the landfill leachate, etc., and adjust the pH value in the softening reactor 6 to 11 -12. The pH of the softening reactor 6 is monitored online by a pH meter 61 .

S6. The softened landfill leachate is transported to the tubular microfiltration membrane 7, and the suspended solids and organic microorganisms in the landfill leachate are filtered and removed to obtain a clear clear liquid.

Wherein, the microfiltration membrane pore size of the tubular microfiltration membrane 7 can be selected as 0.5 μm.

S7, the clear liquid obtained after filtration is transported to the ammonia distillation tower 8 for ammonia distillation treatment to remove ammonia nitrogen in the clear liquid, and also remove part of volatile COD.

Due to the ammonia nitrogen in the supernatant, it mostly exists in the state of ammonia ion (NH4+) and free ammonia ( _NH3 ) and maintains a balance, and the equilibrium relationship between the two is affected by pH value. When the pH value is 7, the ammonia nitrogen mostly exists in the state of NH4+, and when the pH value is about 11, 90% of the ammonia nitrogen exists in the form of _NH3 , and free ammonia ( _NH3 ) is easy to escape from the water. Therefore, in this embodiment, the ammonia distillation tower 8 adopts a blast ammonia gas stripping tower to promote the escape of ammonia from the clear liquid, and the removal rate of ammonia nitrogen by the ammonia distillation tower 8 can reach more than 95%. In order to avoid secondary pollution caused by the escaping ammonia gas, the escaping ammonia gas is recovered by pipeline and pumped to the denitrification system of the power plant.

S8. The effluent of the ammonia distillation tower 8 is sent to the built-in MBR 9, and through denitrification and nitrification, the biochemical organic matter therein is biochemically removed and biological denitrification is carried out, so that the final effluent reaches the discharge standard.

In the built-in MBR 9, the sludge formed by precipitation and accumulation in the denitrification tank 91 and the nitrification tank 92 can be discharged to the sludge tank 10 through a power pump or the like.

Further, as required, the processing method of the present invention also comprises the following steps:

S9. The effluent of the built-in MBR is filtered through the emergency nanofiltration device 12 to reduce the organic matter index of the effluent and ensure that the effluent meets the discharge standard.

In summary, the treatment system and method of the present invention can reduce the production of membrane concentrate, reduce the investment cost per ton of water, treatment cost and floor space for landfill leachate treatment in waste incineration power plants, and achieve cost reduction and good treatment effect. Purpose.

The above descriptions are only the embodiments of the present invention, and are not intended to limit the scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present invention, or directly or indirectly applied to other related technologies Fields are similarly included in the scope of patent protection of the present invention.

Claims (10)

1. a landfill leachate treatment system of a waste incineration power plant, is characterized in that, comprises the primary settling tank of access landfill leachate, the one-stage anaerobic reactor that the landfill leachate is carried out to the middle temperature anaerobic treatment in sequence and secondary anaerobic reactor, anaerobic sedimentation tank, softening reactor for softening anaerobic treatment of landfill leachate, tubular microfiltration membrane for filtration treatment of softened landfill leachate, The obtained clear liquid is subjected to ammonia distillation tower for ammonia distillation, and the built-in MBR for biochemical treatment and filtration treatment of the clear liquid after ammonia distillation; The primary sedimentation tank, the primary anaerobic reactor, the secondary anaerobic reactor, the anaerobic sedimentation tank, the softening reactor, the tubular microfiltration membrane, the ammonia distillation tower and the built-in MBR are processed according to the flow of the landfill leachate. Connect in sequence. 2 . The landfill leachate treatment system according to claim 1 , wherein the landfill leachate treatment system further comprises a basket type disposed at the front end of the primary sedimentation tank for filtering and treating the landfill leachate. 3 . filters and self-cleaning filters. 3 . The landfill leachate treatment system according to claim 2 , wherein the filtration precision of the basket filter is 5 mm or 10 mm; the filtration precision of the self-cleaning filter is 1 mm or 2 mm. 4 . 4 . The landfill leachate treatment system according to claim 1 , wherein the landfill leachate treatment system further comprises a regulating tank for performing homogeneous and homogeneous treatment on the landfill leachate; the regulating pool is connected to between the primary settling tank and the primary anaerobic reactor. 5 . The landfill leachate treatment system according to claim 1 , wherein the anaerobic reaction temperature of the primary anaerobic reactor and the secondary anaerobic reactor is both 35°C to 38°C. 6 . 6 . The landfill leachate treatment system according to claim 1 , wherein the microfiltration membrane pore size of the tubular microfiltration membrane is 0.1-0.5 μm. 7 . 7 . The landfill leachate treatment system according to claim 1 , wherein the landfill leachate treatment system further comprises a sludge tank and a sludge dewatering treatment connected to the sludge tank. 8 . device; the primary sedimentation tank, the primary anaerobic reactor, the secondary anaerobic reactor, the anaerobic sedimentation tank and the built-in MBR are respectively connected to the sludge tank; and/or, The landfill leachate treatment system further includes an emergency nanofiltration device connected to the water outlet end of the built-in MBR to filter the effluent of the built-in MBR. 8. A method for treating landfill leachate in a waste incineration power plant, comprising the following steps: S1. The landfill leachate enters the primary sedimentation tank for preliminary sedimentation treatment; S2. The landfill leachate after preliminary precipitation treatment is transported to the first-stage anaerobic reactor for mesophilic anaerobic treatment, so that the insoluble organic matter in the landfill leachate is decomposed into small molecular substances; S3. Transporting the landfill leachate after the mesothermal anaerobic treatment to the secondary anaerobic reactor for secondary anaerobic treatment to remove the organic matter therein; S4. Transport the landfill leachate after the secondary anaerobic treatment to the anaerobic sedimentation tank for anaerobic sedimentation treatment; S5, the effluent of the anaerobic sedimentation tank is sent to the softening reactor and calcium hydroxide is added for softening treatment, and the amount of calcium hydroxide added is adjusted according to the pH value measured online; S6. Transport the softened landfill leachate to a tubular microfiltration membrane, and filter to remove suspended solids and organic microorganisms in the landfill leachate; S7, the clear liquid obtained after the filtration is transported to the ammonia distillation tower to carry out the ammonia distillation process, and the ammonia nitrogen in the clear liquid is removed; S8. The effluent of the ammonia distillation tower is sent to the built-in MBR, and through denitrification and nitrification, the biochemical organic matter therein is biochemically removed and biological denitrification is carried out. 9. The method for treating landfill leachate according to claim 8, wherein in step S1, before the landfill leachate enters the primary settling tank, it is filtered through a basket filter and a self-cleaning filter in sequence; In step S2, the landfill leachate after preliminary precipitation treatment is firstly transported to the conditioning tank for homogeneous and homogeneous treatment, and then sent to the primary anaerobic reactor. 10. The landfill leachate treatment method according to claim 8 or 9, wherein the landfill leachate treatment method further comprises the following steps: S9, filtering the effluent of the built-in MBR through an emergency nanofiltration device to reduce the organic matter index of the effluent.

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