A kind of old leachate treatment process

Abstract

The present invention discloses a rapid start-up method for treating wastewater with anaerobic ammonium oxidation and a treatment process for aged leachate. The rapid start-up method comprises sequentially performing quality pretreatment, nitrification, synergistic denitrification and anaerobic ammonium oxidation treatment on wastewater with an imbalanced carbon-nitrogen ratio. The treatment process for aged leachate comprises sequentially performing quality pretreatment, nitrification, synergistic denitrification and anaerobic ammonium oxidation treatment on aged leachate. In the present invention, the process combination of "quality pretreatment + nitrification + synergistic denitrification + anaerobic ammonium oxidation" is adopted, which can not only greatly shorten the start-up cycle of the anaerobic ammonium oxidation reactor and ensure rapid start-up of the reactor, but also greatly shorten the hydraulic retention time of each process section, and realize rapid treatment of wastewater with an imbalanced carbon-nitrogen ratio. It has the advantages of short start-up cycle, high treatment efficiency, stable and up-to-standard effluent water quality, etc., and can realize rapid denitrification and full-quantity disposal of C / N ratio imbalanced sewage represented by aged leachate, with high use value and good application prospects.

Description

Technical Field

[0001] The invention relates to a method for treating wastewater by anaerobic ammonium oxidation, and in particular to a rapid start-up method for treating wastewater by anaerobic ammonium oxidation and a process for treating aged leachate. Background Art

[0002] The existing landfill leachate has generally entered the aging stage. Due to the imbalance of C / N ratio and high ammonia nitrogen content, these late-stage leachates (referred to as aged leachate) make it difficult for the effluent ammonia nitrogen and total nitrogen to meet the standards. External carbon sources are required to adjust the water quality, which easily increases the treatment cost. For the above reasons, the anaerobic ammonium oxidation process is often used to treat aged leachate. Before entering the anaerobic ammonium oxidation reactor for treatment, the aged leachate needs to be biochemically treated (such as using A / O short-range nitrification and denitrification to biochemically treat the leachate) to enable the aged leachate to meet the anaerobic ammonium oxidation influent water quality requirements. However, due to the characteristics of the water quality of the aged leachate, the wastewater treated by A / O short-term nitrification and denitrification has a high content of difficult-to-degrade COD, including humic acid, which is not conducive to the growth of anaerobic ammonium oxidation bacteria, the rapid start-up of the reactor and the proliferation of bacteria; at the same time, in order to achieve continuous system treatment, the anaerobic ammonium oxidation influent must carry sludge from the short-term nitrification and denitrification section, which greatly affects the treatment capacity of the anaerobic ammonium oxidation process section. In addition, since the anaerobic ammonium oxidation sludge has high requirements for the composition and stability of sewage, and the components of the aged leachate are complex and the water quality changes greatly, many leachate components including humic acid substances can easily cause the activity of anaerobic ammonium oxidation sludge to decrease, affecting the efficiency of sewage treatment. Therefore, it is necessary to further remove harmful components in the sewage to stabilize the anaerobic ammonium oxidation influent water quality. However, according to the previous research of the inventors of this application, the existing technology for treating aged leachate still has the following defects: (a) The pretreatment process adopted fails to effectively guarantee the stability of the anaerobic ammonium oxidation influent water quality, which results in the bacterial strain denitrification treatment capacity being easily affected by water quality fluctuations, the amount of inoculated sludge is large, the reactor startup operation is complicated, and the startup time is long; (b) The sludge particle morphology in the anaerobic ammonium oxidation reactor is poor, and the sludge proliferation rate is too slow, which results in slow startup speed and poor treatment capacity, making it difficult to efficiently complete the effective treatment of aged leachate; (c) The system operation stability is poor, and the effluent still cannot stably meet the standards. Therefore, it is very necessary to obtain a method for treating aged leachate with a short startup cycle, high treatment efficiency, and stable effluent water quality that meets the standards. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a method for quickly treating aged leachate based on anaerobic ammonia oxidation, which has a short startup cycle, high treatment efficiency and stable effluent quality that meets standards.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] A rapid start-up method for treating wastewater by anaerobic ammonium oxidation comprises the following steps:

[0006] S1. Use material membrane to pre-treat the wastewater with imbalanced carbon-nitrogen ratio by quality separation;

[0007] S2, nitrifying the wastewater after quality separation pretreatment;

[0008] S3, performing coordinated denitrification treatment on the effluent after nitrite treatment;

[0009] S4. The effluent after the synergistic denitrification treatment is subjected to anaerobic ammonium oxidation treatment to complete the rapid start-up of the anaerobic ammonium oxidation treatment of the wastewater.

[0010] The above-mentioned rapid start-up method for anaerobic ammonium oxidation treatment of wastewater is further improved, and the nitrite treatment process also includes: adding effluent discharged during the anaerobic ammonium oxidation treatment process.

[0011] The above-mentioned rapid start-up method for anaerobic ammonium oxidation treatment of wastewater is further improved, and the collaborative denitrification treatment process also includes: adding anaerobic ammonium oxidation sludge discharged during the anaerobic ammonium oxidation treatment process.

[0012] The above-mentioned rapid start-up method for anaerobic ammonium oxidation treatment of wastewater is further improved, and the anaerobic ammonium oxidation treatment process also includes: utilizing the nitrogen generated during the anaerobic ammonium oxidation treatment process for cyclic aeration.

[0013] The above-mentioned rapid start-up method for anaerobic ammonium oxidation treatment of wastewater is further improved, in which during the nitritation treatment process, the reflux ratio of the effluent discharged during the anaerobic ammonium oxidation treatment process back to the nitritation treatment system is not less than 3; further preferably, the reflux ratio of the effluent discharged during the anaerobic ammonium oxidation treatment process is 3 to 7.

[0014] The above-mentioned rapid start-up method for treating wastewater by anaerobic ammonium oxidation is further improved, wherein the aeration rate of nitrogen in the cyclic aeration process is 2L-5L / (min•m 3 ).

[0015] The above-mentioned rapid start-up method for anaerobic ammonia oxidation treatment of wastewater is further improved, and before the carbon-nitrogen ratio imbalance wastewater is subjected to quality pretreatment, it also includes: filtering the carbon-nitrogen ratio imbalance wastewater to remove SS; the mass ratio of ammonia nitrogen and nitrite nitrogen in the carbon-nitrogen ratio imbalance wastewater is less than 1:1.32; the carbon-nitrogen ratio imbalance wastewater is aged leachate from a landfill.

[0016] As a general technical concept, the present invention also provides a process for treating aged leachate, comprising the following steps:

[0017] (1) Using material membrane to pre-treat the aged leachate to obtain a light phase and a concentrated phase;

[0018] (2) subjecting the light phase after the quality separation pretreatment to nitrite treatment;

[0019] (3) Co-denitrification treatment of the effluent after nitrite treatment;

[0020] (4) The effluent after the synergistic denitrification treatment is subjected to anaerobic ammonium oxidation treatment to complete the treatment of the aged leachate.

[0021] The above-mentioned aged leachate treatment process is further improved, in said (2), the nitrite treatment process further includes: adding the effluent discharged during the anaerobic ammonium oxidation treatment process; the reflux ratio of the effluent discharged during the anaerobic ammonium oxidation treatment process to the nitrite treatment system is not less than 3; further preferably, the reflux ratio of the effluent discharged during the anaerobic ammonium oxidation treatment process is 3 to 7.

[0022] The above-mentioned aged leachate treatment process is further improved in that in said (3), the said coordinated denitrification treatment process further includes: adding anaerobic ammonium oxidation sludge discharged during the anaerobic ammonium oxidation treatment process.

[0023] The above aged leachate treatment process is further improved, wherein in said (4), the anaerobic ammonium oxidation treatment process further comprises: utilizing the nitrogen generated in the anaerobic ammonium oxidation treatment process for cyclic aeration; the aeration rate of nitrogen in the cyclic aeration process is 2L-5L / (min•m 3 ).

[0024] The above-mentioned aged leachate treatment process is further improved, wherein in said (1), before the aged leachate is subjected to quality pretreatment, the aged leachate is further subjected to: filtering the aged leachate to remove SS; the post-treatment of the concentrated phase comprises: subjecting the concentrated phase to degradation treatment to remove refractory organic pollutants, solid-liquid separation to obtain an aqueous phase and sludge; the aqueous phase is returned to the synergistic denitrification treatment system in step (3) as a carbon source; and the sludge obtained after the solid-liquid separation is mixed with the SS in the aged leachate and subjected to sludge deep treatment.

[0025] The above-mentioned aged leachate treatment process is further improved, in said (2), the light phase after the separation pretreatment is subjected to nitrification treatment until the mass ratio of ammonia nitrogen to nitrite nitrogen in the system is close to or lower than 1:1.32; the inoculation amount of nitrification sludge in the nitrification process is 6g / L~8g / L; the initial residence time of the nitrification treatment is 4d~6d; the nitrification process also includes aeration treatment of the light phase after the separation pretreatment, and the dissolved oxygen content of the system is controlled to be 0.3 mg / L~0.6mg / L; the residual sludge generated in the nitrification process is mixed with the concentrated phase and then treated together.

[0026] The above-mentioned aged leachate treatment process is further improved, in which in (3), the effluent after nitrite treatment is subjected to synergistic denitrification treatment until the mass ratio of ammonia nitrogen to nitrite nitrogen in the system is 1:1.32; the sludge produced by nitrite treatment and anaerobic ammonium oxidation treatment is used as inoculated sludge in the synergistic denitrification treatment; and the initial residence time of the synergistic denitrification treatment is 4d to 6d.

[0027] The above-mentioned aged leachate treatment process is further improved, in said (4), the inoculation amount of anaerobic ammonium oxidation sludge during the anaerobic ammonium oxidation treatment process is 3g / L~5g / L; the initial residence time of the anaerobic ammonium oxidation treatment is 4d~6d; the effluent discharged after the anaerobic ammonium oxidation treatment is sent to the BAF tank for treatment.

[0028] Compared with the prior art, the advantages of the present invention are:

[0029] (1) In view of the defects of the existing anaerobic ammonium oxidation process such as the long start-up period, the present invention creatively proposes a rapid start-up method for anaerobic ammonium oxidation wastewater treatment, which ensures the water quality of the anaerobic ammonium oxidation influent by "quality separation pretreatment + nitrite-synergistic denitrification". By coupling the functions of the nitrite-anaerobic ammonium oxidation three-tank system, the growth inhibition of the anaerobic ammonium oxidation bacteria by the front-end influent water quality is relieved, and the start-up period of the reactor is greatly shortened. Specifically: the process combination of "quality separation pretreatment + nitrite + synergistic denitrification" can be used to adjust the influent water quality of anaerobic ammonium oxidation step by step, and effectively remove the harmful components in the wastewater with an imbalanced carbon-nitrogen ratio (such as non-degradable COD such as humic acid / fulvic acid / fulvic acid substances) while ensuring the stability of the influent water quality of anaerobic ammonium oxidation. It can not only solve the problem of anaerobic ammonium oxidation, but also effectively remove the harmful components in the wastewater with an imbalanced carbon-nitrogen ratio (such as humic acid / fulvic acid / fulvic acid substances and other non-degradable COD). In addition to the growth inhibition of anaerobic ammonium oxidizing bacteria by adverse factors such as water quality fluctuations and harmful substances, the activity of anaerobic ammonium oxidizing bacteria can be rapidly improved and the enrichment and proliferation can be accelerated, thereby greatly shortening the reactor startup cycle, and improving the operating stability of the anaerobic ammonium oxidation system, accelerating the enrichment rate, and facilitating rapid startup; at the same time, the coupled denitrification process of "nitrite + synergistic denitrification + anaerobic ammonium oxidation" can simplify the sludge community and functional evolution of the anaerobic ammonium oxidation section, and realize sludge functional zoning by strengthening the directional treatment of pollutants by microorganisms in each process section, simplify process control, greatly shorten the startup cycle of the anaerobic ammonium oxidation reactor, and ensure rapid startup of the anaerobic ammonium oxidation reactor. The startup time under low sludge inoculation conditions can be shortened by at least 1 / 3.

[0030] (2) In the rapid start-up method of the present invention, by returning the effluent discharged from the anaerobic ammonium oxidation treatment process to the nitrite treatment process, and returning the anaerobic ammonium oxidation sludge discharged from the anaerobic ammonium oxidation treatment process to the coordinated denitrification treatment process, the sludge granulation can be accelerated, the sludge particle morphology can be effectively improved, and the sludge enrichment and proliferation can be accelerated, thereby greatly accelerating the start-up of the reactor and also greatly reducing the amount of water quality conditioning agents used.

[0031] (3) In view of the defects of the existing anaerobic ammonium oxidation process, such as long start-up cycle, low treatment efficiency, poor operation stability and inability to achieve efficient denitrification of aged leachate, the present invention creatively proposes an aged leachate treatment process, which can not only achieve rapid start-up of anaerobic ammonium oxidation, but also achieve rapid denitrification of aged leachate. Specifically: by adopting the process combination of "quality-based pretreatment + nitrite + synergistic denitrification", the influent water quality of anaerobic ammonium oxidation can be adjusted step by step, and the influent water quality of anaerobic ammonium oxidation can be ensured to be stable while effectively removing harmful components in aged leachate (such as non-degradable COD such as humic acid / fulvic acid / fulvic acid substances). It can not only eliminate the growth inhibition of anaerobic ammonium oxidation bacteria caused by adverse factors such as water quality fluctuations and harmful substances, but also enable the activity of anaerobic ammonium bacteria to be rapidly improved and accelerate enrichment and proliferation, thereby greatly shortening the reactor start-up cycle, but also can In order to improve the operational stability of the anaerobic ammonium oxidation system, accelerate the enrichment rate, and also facilitate rapid startup; at the same time, the coupled denitrification process of "nitritation + synergistic denitrification + anaerobic ammonium oxidation" can simplify the sludge community and functional evolution of the anaerobic ammonium oxidation section, and by strengthening the directional treatment of pollutants by microorganisms in each process section, the functional zoning of sludge can be achieved, and the process control can be simplified. It can not only greatly shorten the startup cycle of the anaerobic ammonium oxidation reactor and ensure the rapid startup of the anaerobic ammonium oxidation reactor, but also greatly shorten the hydraulic retention time of each process section, and realize the rapid treatment of aged leachate. At the same time, with the help of pre-nitritation + synergistic denitrification process, the activity inhibition of the anaerobic ammonium oxidation treatment process due to water quality fluctuations can be effectively relieved, and the synergistic denitrification effect between nitritation and anaerobic ammonium oxidation sludge particles can be significantly enhanced, thereby achieving synergistic and efficient denitrification, and the treatment efficiency can be significantly improved while ensuring effective denitrification. Therefore, the aged leachate treatment process of the present invention can not only realize the rapid start-up of aged leachate in anaerobic ammonia oxidation, but also realize efficient denitrification treatment of aged leachate, and has the advantages of short start-up cycle, high treatment efficiency, stable effluent water quality meeting standards, etc. It can be widely used in treating C / N imbalanced sewage represented by aged leachate, and can realize rapid denitrification and full-quantity disposal, with high use value and good application prospects.

[0032] (4) In the aged leachate treatment process of the present invention, by returning the effluent discharged from the anaerobic ammonium oxidation treatment process to the nitrite treatment process, and returning the anaerobic ammonium oxidation sludge discharged from the anaerobic ammonium oxidation treatment process to the coordinated denitrification treatment process, the sludge granulation can be accelerated, the sludge particle morphology can be effectively improved, and the sludge enrichment and proliferation can be accelerated, thereby greatly accelerating the start-up of the reactor and also greatly reducing the amount of water quality conditioning agents used. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0034] Figure 1 The figure is a schematic diagram of the rapid start-up process flow of the anaerobic ammonium oxidation wastewater treatment of the present invention.

[0035] Figure 2 It is a schematic diagram of the coupled denitrification process flow of anaerobic ammonia oxidation wastewater treatment of the present invention. DETAILED DESCRIPTION

[0036] The present invention is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present invention is not limited thereby.

[0037] In the following examples, unless otherwise specified, the materials and instruments used are commercially available, the processes used are conventional processes, the equipment used are conventional equipment, and the data obtained are the average values ​​of more than three repeated experiments.

[0038] Example 1

[0039] A rapid start-up method for treating wastewater by anaerobic ammonium oxidation, specifically: a rapid start-up method for treating aged leachate from a landfill by anaerobic ammonium oxidation, such as Figure 1 and Figure 2 As shown, the following steps are included:

[0040] (1) Filter the aged leachate (wastewater with an unbalanced carbon-nitrogen ratio, where the mass ratio of ammonia nitrogen to nitrite nitrogen is less than 1:1.32) to remove SS. Specifically, the aged leachate stock solution is pumped to the inlet pool and SS is removed by methods including but not limited to flotation and / or microfiltration to perform wastewater pretreatment.

[0041] (2) Material membrane is used to perform quality separation pretreatment on aged leachate after sewage pretreatment, specifically: suspended or free humic acid / fulvic acid / fulvic acid substances in water are separated by material membrane to achieve sewage quality separation pretreatment. The sewage after separation by material membrane is divided into concentrated phase and light phase, wherein the concentrated phase intercepts most of the non-degradable COD such as humic acid / fulvic acid / fulvic acid substances, so that the water quality of the light phase can be further improved. At the same time, the concentrated phase of the material membrane is subjected to preliminary degradation of organic matter by methods including but not limited to electrocatalytic oxidation / ozone / Fenton / hydrolysis, and the degraded water phase is used as a supplementary carbon source for sewage treatment. The degraded sludge is mixed with SS for sludge deep treatment.

[0042] (3) The light phase obtained after the quality pretreatment is subjected to nitrification treatment, specifically: the light phase after material membrane separation enters the nitrification tank for nitrification treatment until, in the process, the NH4+ -N (ammonia nitrogen) is gradually oxidized to NO2 - -N (nitrite nitrogen) and ammonia nitrogen content are reduced, and part of the COD in the sewage is consumed. The excess sludge generated in this step is transferred to step (2) and mixed with the material membrane concentrated phase for degradation treatment.

[0043] (4) The effluent after nitrite treatment is subjected to coordinated denitrification treatment, specifically: when NH4 + -N (ammonia nitrogen) and NO2 - -N (nitrite nitrogen) ratio is close to or lower than 1:1.32, the sewage is transferred to the synergistic denitrification section (synergistic denitrification tank) for treatment, and the small amount of NO3 - -N (nitrate), reduced to nitrogen gas and / or NO2 - -N, and further absorb COD in sewage. The ratio of ammonia nitrogen to nitrite nitrogen in sewage treated by the synergistic denitrification process can be stably adjusted to 1:1.32.

[0044] (5) The effluent after the synergistic denitrification treatment is subjected to anaerobic ammonium oxidation treatment. Specifically, when the ratio of ammonia nitrogen to nitrite nitrogen in the sewage in the synergistic denitrification section can be stably adjusted to 1:1.32, the sewage is transferred to the anaerobic ammonium oxidation reactor for anaerobic ammonium oxidation to reduce the NO2 - -N is converted into nitrogen gas, completing the rapid start-up of anaerobic ammonium oxidation treatment of wastewater.

[0045] During the anaerobic ammonium oxidation treatment process, all the discharged effluent is added to the nitrification tank, and all the discharged sludge is added to the synergistic denitrification tank. Therefore, the operation of the rapid startup process of the present invention is always accompanied by efficient "nitrification-synergistic denitrification-anaerobic ammonium oxidation-nitrification" water quality cycle callback and sludge cycle inoculation, which greatly accelerates the startup of the reactor, reduces the input of water quality conditioning agents, and makes full use of the remaining sludge. The functions of the reactor units are directed to cleaning and functional coupling, and the efficiency is significantly improved. At the same time, the nitrogen generated during the anaerobic ammonium oxidation treatment process is used as a gas source and returned to the anaerobic ammonium oxidation reactor for external circulation aeration. The aeration rate of nitrogen during the circulation aeration process is 2L~5L / (min•m 3 ), circulating aeration can promote the mass transfer between pollutants and bacteria, and protect the particle morphology of bacteria.

[0046] (6) After the coupled denitrification treatment of nitrite, synergistic denitrification and anaerobic ammonium oxidation, the sewage (anaerobic ammonium oxidation effluent) can be guaranteed to stably meet the standards, and the sewage can meet the discharge standards after being treated in the BAF microbial filter. In the treatment process of the present invention, COD also undergoes multiple degradation treatments, and the effluent water quality stably meets the standards.

[0047] The following takes the aged leachate from a landfill in Changsha as an example to illustrate the specific implementation method, in which the inoculation amount of nitrite sludge is 6-8 g / L, and the initial residence time is 4-6 days; the synergistic denitrification adopts nitrite + anaerobic ammonium oxidation return sludge for inoculation, and the initial residence time is 4-6 days; the inoculation amount of anaerobic ammonium oxidation is 3-5 g / L, and the initial residence time is 4-6 days.

[0048] The water quality data of each process section are as follows:

[0049] Water quality of material membrane influent (wastewater after SS removal): COD 1650mg / L, ammonia nitrogen 2100 mg / L, nitrite nitrogen <2mg / L, nitrate nitrogen <5mg / L, B / C 0.15~0.18.

[0050] Material membrane light phase (nitrite inlet) water quality: COD 450mg / L, ammonia nitrogen 2250 mg / L, nitrite nitrogen <2mg / L, nitrate nitrogen <5mg / L, B / C 0.22~0.24.

[0051] Nitrite effluent (co-denitrification influent) water quality: COD 170~220mg / L, ammonia nitrogen 760~880 mg / L, nitrite nitrogen 980~1120mg / L, nitrate nitrogen <5mg / L, B / C 0.15-0.17.

[0052] Water quality of organic matter degradation water phase (carbon source): COD 6150 mg / L, ammonia nitrogen 1825 mg / L, nitrite nitrogen <2 mg / L, nitrate nitrogen <5 mg / L, B / C 0.26~0.30.

[0053] Water quality of synergistic denitrification effluent (anaerobic ammonium oxidation influent): COD 90~140mg / L, ammonia nitrogen 390~425 mg / L, nitrite nitrogen 500~560mg / L, nitrate nitrogen <5mg / L, B / C 0.15~0.18.

[0054] Anaerobic ammonium oxidation effluent (BAF influent) water quality: COD 80~110mg / L, total nitrogen <25mg / L.

[0055] BAF effluent quality: COD 25~40mg / L, total nitrogen <8 mg / L.

[0056] Table 1 Other indicators of treated effluent (unit: mg / L)

[0057]

[0058] From the above results, it can be seen that after the SS is removed from the landfill leachate in the regulating tank, it enters the material membrane separation pretreatment. Most of the difficult-to-degrade COD is enriched in the concentrated phase and needs to be further degraded. The light phase is treated by a coupled denitrification process. The retention rate of humic acid substances by the material membrane is ≥95%, and the B / C ratio of the light phase is increased to 0.22~0.25, which is suitable for nitrite treatment. Nitrite is controlled by aeration and sewage NH4 + -N content and microbial NO2 - The oxidation rate of sewage NH4 + -N (ammonia nitrogen): NO2 - -N (nitrite nitrogen) is accurately controlled. When the mass ratio of the two (in terms of N) gradually decreases to 1:1.32, synergistic denitrification can be carried out. The small amount of NO3 - -N (nitrate nitrogen) uses the water phase after the degradation of organic matter in the concentrated phase of the material membrane to supplement the C source for denitrification, further remove nitrate nitrogen and accurately control the mass ratio of ammonia nitrogen: nitrite nitrogen at 1:1.32, and then complete the sewage denitrification by anaerobic ammonia oxidation. The entire sewage treatment process can be operated in a continuous flow or batch mode, in which the precise control of the nitrite tank reaction can be achieved through aeration (dissolved oxygen (DO) is 0.3-0.6 mg / L), and the precise control of the mass ratio of ammonia nitrogen: nitrite nitrogen in the anaerobic ammonia oxidation inlet (1:1.32) can be achieved through nitrite + synergistic denitrification, and finally discharged after BAF treatment. After treatment by the above method, the effluent COD = 10.5 mg / L, ammonia nitrogen = 2.8 mg / L, and total nitrogen < 8 mg / L, which fully meets the emission standard requirements of GB16889-2008.

[0059] In the rapid start-up method for treating wastewater with anaerobic ammonium oxidation of the present invention, an endogenous sludge circulation inoculation process is adopted to accelerate the start-up of the reactor. After 33-45 days of continuous flow operation, the concentrations of the synergistic denitrification and anaerobic ammonium oxidation sludge are both increased to 6-8 g / L, and the sludge is rapidly enriched and proliferated. The denitrification load of the anaerobic ammonium oxidation reactor exceeds 0.5 kgN / m 3 *d, the reactor is started up, and the start-up time is shortened by about 1 / 3 compared with the prior art. The residence time of each process section is shortened to 2-3d, and the processing capacity is greatly improved. In addition, the "nitrite + synergistic denitrification + anaerobic ammonium oxidation" coupled denitrification process adopted in the present invention has an overall biochemical section total nitrogen removal rate of more than 99%, and the anaerobic ammonium oxidation effluent enters the BAF microbial filter unit, the effluent is stable and meets the standards, and no terminal concentrate is produced.

[0060] Example 2

[0061] A process for treating aged leachate, specifically using anaerobic ammonium oxidation to rapidly treat aged leachate nanofiltration concentrate, such as Figure 1 and Figure 2As shown, the following steps are included:

[0062] (1) Filter the aged leachate to remove SS. Specifically, pump the nanofiltration concentrate of the aged leachate to the inlet pool and remove SS by methods including but not limited to flotation and / or microfiltration. The quality of the sewage after SS removal is: COD 2560 mg / L, ammonia nitrogen 2150 mg / L, nitrite nitrogen <2 mg / L, nitrate nitrogen <5 mg / L, B / C 0.17~0.21.

[0063] (2) Material membrane was used to pre-treat the aged leachate to obtain a light phase and a concentrated phase. The water quality of the light phase (nitrite influent) of the material membrane was as follows: COD 560 mg / L, ammonia nitrogen 1990 mg / L, nitrite nitrogen <2 mg / L, nitrate nitrogen <5 mg / L, B / C 0.19~0.23.

[0064] In this step, most of the non-degradable COD such as humic acid / fulvic acid / fulvic acid substances are intercepted in the concentrated phase. The concentrated phase is degraded by adopting methods including but not limited to electrocatalytic oxidation / ozone / Fenton / hydrolysis, and the non-degradable COD in the concentrated phase is converted into small molecular organic matter. Therefore, the degraded water phase is used as a supplementary carbon source for sewage treatment. The degraded sludge is mixed with SS for deep sludge treatment. Water quality of organic matter degradation water phase (degraded water phase): COD 5550mg / L, ammonia nitrogen 1700 mg / L, nitrite nitrogen <2mg / L, nitrate nitrogen <5mg / L, B / C 0.23~0.26.

[0065] (3) The light phase after the quality separation pretreatment is subjected to nitrification treatment, specifically: the light phase of the material membrane is transferred to the nitrification tank for nitrification treatment. During the nitrification treatment process, aeration control and sewage NH4 + -N content and microbial NO2 - The oxidation rate of sewage NH4 + -N (ammonia nitrogen): NO2 - -N (nitrite nitrogen) is accurately controlled. When the mass ratio of the two (in terms of N) gradually decreases to 1:1.32, the synergistic denitrification treatment can be carried out. In this step, the water quality of nitrite effluent (synergistic denitrification influent) is: COD 260~310mg / L, ammonia nitrogen 900~900 mg / L, nitrite nitrogen 1020~1190mg / L, nitrate nitrogen <5mg / L, B / C 0.15-0.16. The residual sludge generated in this step is transferred to step (2) and mixed with the material membrane concentrated phase for degradation treatment.

[0066] (4) The effluent after nitrite treatment is subjected to synergistic denitrification treatment. Specifically, the effluent from nitrite treatment is transferred to the synergistic denitrification pool for further treatment. The small amount of NO3- -N (nitrate nitrogen) uses the water phase after the degradation of organic matter in the concentrated phase of the material membrane to supplement the C source for denitrification, further remove nitrate nitrogen and accurately control the mass ratio of ammonia nitrogen: nitrite nitrogen at 1:1.32. In this step, the water quality of the synergistic denitrification effluent (anaerobic ammonia oxidation influent) is: COD 100~120mg / L, ammonia nitrogen 400~465mg / L, nitrite nitrogen 530~610mg / L, nitrate nitrogen <5mg / L, B / C 0.22~0.25.

[0067] (5) The effluent after the synergistic denitrification treatment is subjected to anaerobic ammonium oxidation treatment. Specifically, when the ratio of ammonia nitrogen to nitrite nitrogen in the sewage in the synergistic denitrification section can be stably adjusted to 1:1.32, the sewage is transferred to the anaerobic ammonium oxidation reactor for anaerobic ammonium oxidation to reduce the NO2 - -N is converted into nitrogen gas to complete the treatment of aged leachate. In this step, the water quality of BAF influent (anaerobic ammonium oxidation effluent) is: COD 110~140mg / L, total nitrogen <40mg / L.

[0068] During the anaerobic ammonium oxidation treatment process, all the discharged effluent is added to the nitrification tank, and all the discharged sludge is added to the synergistic denitrification tank. Therefore, the operation of the rapid startup process of the present invention is always accompanied by efficient "nitrification-synergistic denitrification-anaerobic ammonium oxidation-nitrification" water quality cycle callback and sludge cycle inoculation, which greatly accelerates the startup of the reactor, reduces the input of water quality conditioning agents, and makes full use of the remaining sludge. The functions of the reactor units are directed to cleaning and functional coupling, and the efficiency is significantly improved. At the same time, the nitrogen generated during the anaerobic ammonium oxidation treatment process is used as a gas source and returned to the anaerobic ammonium oxidation reactor for external circulation aeration. The aeration rate of nitrogen during the circulation aeration process is 2L~5L / (min•m 3 ), circulating aeration can promote the mass transfer between pollutants and bacteria, and protect the particle morphology of bacteria.

[0069] (6) After the coupled denitrification treatment of nitrite, synergistic denitrification and anaerobic ammonium oxidation, the sewage (anaerobic ammonium oxidation effluent) can be guaranteed to meet the standards stably, and the sewage meets the discharge standards after being treated in the BAF microbial filter. In the treatment process of the present invention, COD also undergoes multiple degradation treatments, and the effluent water quality is stably up to the standards. In this step, the BAF effluent water quality: COD 15~30mg / L, total nitrogen <10mg / L.

[0070] In the process of Example 2, the inoculum amount of nitrite sludge is 6-8 g / L, and the initial residence time is 4-6 days; the coordinated denitrification adopts nitrite + anaerobic ammonium oxidation return sludge for inoculation, and the initial residence time is 4-6 days; the inoculum amount of anaerobic ammonium oxidation is 3-5 g / L, and the initial residence time is 4-6 days.

[0071] Table 2 Other indicators of treated effluent (unit: mg / L)

[0072]

[0073] The results show that after treatment by the above method, the effluent COD is 15-30 mg / L and the total nitrogen is less than 10 mg / L. The total nitrogen removal rate is ≥99%; all pollutant indicators are significantly lower than the existing pollutant emission concentration limit of domestic waste landfills, as shown in Table 2. The process of the present invention, after continuous flow operation for 35-48 days, the concentration of synergistic denitrification and anaerobic ammonium oxidation sludge is increased by 6-8 g / L, and the sludge is rapidly enriched and proliferated. The denitrification load of the anaerobic ammonium oxidation reactor exceeds 0.45 kgN / m 3 *d, the reactor was started up, and the startup time was shortened by about 1 / 3 compared with the existing technology. The residence time of each process section was shortened to 2-3d, and the processing capacity was greatly improved. The effluent was stable and up to standard, and no terminal concentrate was produced.

[0074] Based on the above results, it can be seen that compared with the conventional method of treating aged leachate by anaerobic ammonium oxidation, the process of the present invention combines material membrane + nitrite-anaerobic ammonium oxidation premixing synergistic pretreatment and anaerobic ammonium oxidation as a microbial filter process, which has the following advantages: (1) The use of material membrane separation + nitrite-anaerobic ammonium oxidation premixing synergistic denitrification pretreatment strengthens the directional treatment of pollutants by microorganisms in each process section, simplifies the functions of bacteria at each level, and enables rapid startup of the reactor. (2) The step-by-step process combination avoids the impact of harmful substances in the aged leachate on the anaerobic ammonium oxidation system, and the system has high operating stability and fast enrichment and proliferation. (3) The endogenous sludge circulation inoculation process is used to accelerate the startup of the reactor, shorten the hydraulic retention time to 2-3 days, shorten the startup time by 1 / 3 under low sludge inoculation conditions, simplify the process, and make the control simple. (4) The sludge granulation is accelerated by N2 external circulation aeration + synergistic denitrification. The endogenous C source is circulated and the residual sludge is reused. All anaerobic ammonium oxidation sludge is reused to further promote the formation of granular sludge and shorten the start-up time. Part of the effluent is returned to adjust the water quality of the previous nitrite. (5) It can achieve full quantitative treatment of wastewater with unbalanced C / N ratio represented by aged leachate, without the production of terminal concentrated liquid, and the effluent quality is stable and up to standard. Therefore, in the present invention, the water quality of anaerobic ammonia oxidation influent is guaranteed by "quality-based pretreatment + nitrite-synergistic denitrification", and the growth inhibition of anaerobic ammonia oxidation bacteria by the front-end influent water quality is relieved through the functional coupling of the nitrite-anaerobic ammonia oxidation three-tank system, thereby greatly shortening the reactor startup cycle; with the help of the pre-nitrite + synergistic denitrification process, the activity inhibition of the anaerobic ammonia oxidation treatment process due to water quality fluctuations is relieved, and the synergistic denitrification effect between nitrite and anaerobic ammonia oxidation sludge particles is significantly enhanced; the N2 external circulating aeration + synergistic denitrification technology is adopted to accelerate the sludge granulation, effectively improve the sludge particle morphology, and accelerate the sludge enrichment and proliferation; no terminal concentrated liquid is produced, thereby realizing the full quantitative treatment of C / N ratio imbalance sewage represented by aged leachate.

[0075] The above is only a preferred embodiment of the present invention, but it is not intended to limit the present invention. Any person skilled in the art can make many possible changes and modifications to the technical solution of the present invention using the methods and technical contents disclosed above. Therefore, any simple modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A process for treating aged leachate, characterized in that: The following steps are involved: (1) using a material membrane to pre-treat the aged leachate to obtain a light phase and a concentrated phase; the mass ratio of ammonia nitrogen to nitrite nitrogen in the aged leachate is less than 1:1.32; (2) subjecting the light phase after the separation pretreatment to nitrification treatment until the mass ratio of ammonia nitrogen to nitrite nitrogen in the system is close to 1:1.32; The nitrite treatment process also includes: adding effluent discharged during the anaerobic ammonium oxidation treatment process; the effluent discharged during the anaerobic ammonium oxidation treatment process is returned to the nitrite treatment system at a reflux ratio of not less than 3; (3) performing a coordinated denitrification treatment on the effluent after the nitrite treatment until the mass ratio of ammonia nitrogen to nitrite nitrogen in the system is 1:1.32; the sludge produced by the nitrite treatment and the anaerobic ammonium oxidation treatment is used as inoculated sludge in the coordinated denitrification treatment; the coordinated denitrification treatment process also includes: adding anaerobic ammonium oxidation sludge discharged during the anaerobic ammonium oxidation treatment process; (4) subjecting the effluent after the coordinated denitrification treatment to anaerobic ammonium oxidation treatment to complete the treatment of the aged leachate; the anaerobic ammonium oxidation treatment process also includes: utilizing the nitrogen generated during the anaerobic ammonium oxidation treatment process for cyclic aeration.

2. The process for treating aged leachate according to claim 1, characterized in that: In step (4), the aeration rate of nitrogen during the cyclic aeration process is 2L to 5L / (min•m 3 ).

3. The aged leachate treatment process according to claim 1 or 2, characterized in that: In step (1), before the aged leachate is subjected to the pretreatment of quality separation, the aged leachate is filtered to remove SS; the post-treatment of the concentrated phase comprises: degrading the concentrated phase to remove the refractory organic pollutants, and performing solid-liquid separation to obtain an aqueous phase and sludge; the aqueous phase is returned to the synergistic denitrification treatment system in step (3) as a carbon source; and the sludge obtained after the solid-liquid separation is mixed with the SS in the aged leachate and then subjected to sludge deep treatment.

4. The process for treating aged leachate according to claim 1 or 2, characterized in that: In step (2), the inoculation amount of the nitrite sludge in the nitrite treatment process is 6 g / L to 8 g / L; the initial residence time of the nitrite treatment is 4 d to 6 d; the nitrite treatment process also includes aeration treatment of the light phase after the quality separation pretreatment, and the dissolved oxygen content of the system is controlled to be 0.3 mg / L to 0.6 mg / L; the excess sludge generated in the nitrite treatment process is mixed with the dense phase and then treated together.

5. The aged leachate treatment process according to claim 1 or 2, characterized in that: In step (3), the initial residence time of the coordinated denitrification treatment is 4 to 6 days.

6. The process for treating aged leachate according to claim 1 or 2, characterized in that: In step (4), the inoculation amount of anaerobic ammonium oxidation sludge during the anaerobic ammonium oxidation treatment is 3 g / L to 5 g / L; the initial residence time of the anaerobic ammonium oxidation treatment is 4 d to 6 d; and the effluent discharged after the anaerobic ammonium oxidation treatment is sent to a BAF tank for treatment.

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