Method and system for treating sludge hydrothermal carbonization liquid

Abstract

The invention relates to the field of sewage treatment, in particular to a treatment method and system for a sludge hydrothermal carbonization solution. The treatment method provided by the invention comprises the following steps: adjusting the pH value of the sludge hydrothermal carbonization solution to 5-6 to obtain an initially adjusted carbonization solution; carrying out hydrolytic acidification reaction on the primarily adjusted carbonized solution to obtain a hydrolytic acidification carbonized solution; carrying out methanogenesis reaction on the hydrolytic acidification carbonization solution to obtain an anaerobic digestion carbonization solution; performing multi-stage anaerobic-aerobic denitrification treatment on the anaerobic digestion carbonization solution to obtain a denitrified carbonization solution; dephosphorizing the denitrified carbonized solution to obtain a dephosphorized carbonized solution; and carrying out resin adsorption on the dephosphorized carbonized liquid, and then discharging the dephosphorized carbonized liquid. The treatment method provided by the invention can effectively remove organic matters and nitrogen and phosphorus compounds contained in the sludge hydrothermal carbonization liquid. The concentrations of various pollutants in the discharged water meet the water quality standard of sewage discharged into urban sewers, and the problem of secondary pollution to the environment caused by wastewater generated by a sludge hydrothermal carbonization technology is solved.

Description

Technical Field

[0001] The invention relates to the field of sewage treatment, and in particular to a method and system for treating sludge hydrothermal carbonization liquid. Background Art

[0002] Sludge hydrothermal carbonization is an efficient and environmentally friendly sludge treatment technology developed in recent years, which can achieve resource recovery and utilization. However, in actual application, sludge hydrothermal carbonization technology will produce a certain amount of wastewater, which may contain unreacted organic matter and heavy metals and other pollutants. These wastewaters need to be effectively treated, otherwise they will cause secondary pollution to the environment. Summary of the invention

[0003] The object of the present invention is to provide a method and system for treating sludge hydrothermal carbonization liquid, so as to avoid secondary pollution to the environment caused by wastewater generated by sludge hydrothermal carbonization technology.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] In one aspect, the present invention provides a method for treating sludge hydrothermal carbonization liquid, comprising the following steps:

[0006] (1) adjusting the pH of the sludge hydrothermal carbonized liquid to 5-6 to obtain a primary carbonized liquid;

[0007] (2) subjecting the initially adjusted carbonized liquid to a hydrolysis and acidification reaction to obtain a hydrolysis and acidification carbonized liquid;

[0008] (3) subjecting the hydrolyzed and acidified carbonized liquid to a methanogenic reaction to obtain an anaerobic digested carbonized liquid;

[0009] (4) subjecting the anaerobic digestion carbonized liquid to a multi-stage anaerobic-aerobic denitrification treatment to obtain a denitrified carbonized liquid;

[0010] (5) removing phosphorus from the denitrified carbonized liquid to obtain a dephosphorized carbonized liquid;

[0011] (6) The dephosphorization carbonization liquid is discharged after being adsorbed by resin.

[0012] Preferably, the hydrolysis and acidification reaction is carried out in an upflow anaerobic sludge blanket reactor, and the sludge inoculated in the upflow anaerobic sludge blanket reactor includes landfill leachate sludge, and the inoculation concentration is 10-20 g / L;

[0013] The hydraulic retention time of the hydrolysis and acidification reaction is 8-24 hours, the temperature is 25-45° C., and the pH is 5.5-6.5.

[0014] Preferably, an organic nitrogen enhancement treatment bacterial agent is added to the hydrolysis and acidification reaction, and the inoculation amount is 0.15%-0.25% of the volume of the upflow anaerobic sludge blanket reactor.

[0015] Preferably, the organic nitrogen enhanced treatment bacterial agent comprises Sonora Desert Bacillus and / or Clostridium.

[0016] Preferably, the methanogenic reaction is carried out in an internal circulation anaerobic reactor, and the sludge inoculated in the internal circulation anaerobic reactor includes landfill leachate sludge, and the inoculation concentration is 10-30 g / L;

[0017] The hydraulic retention time of the methanogenic reaction is 6-18 hours, the temperature is 25-45° C., the pH is 6-7.5, and the internal circulation ratio is 10-20.

[0018] Preferably, the number of stages of the multi-stage anaerobic-aerobic denitrification treatment is ≥ 2, wherein the hydraulic retention time of each anaerobic unit is 1-3 hours, the hydraulic retention time of each aerobic unit is 4-8 hours, and the internal reflow ratio is 0-50%.

[0019] Preferably, the multi-stage anaerobic-aerobic denitrification treatment device comprises a multi-stage anaerobic-aerobic denitrification tank and a secondary sedimentation tank, and the external reflow ratio of the multi-stage anaerobic-aerobic denitrification tank to the secondary sedimentation tank is 50-100%;

[0020] The anaerobic digestion carbonized liquid enters the anaerobic-aerobic denitrification tank through a multi-stage water inlet mode, and the water inlet ratio of each stage of the anaerobic-aerobic unit is independently 0-50%.

[0021] Preferably, the phosphorus removal method includes flocculation phosphorus removal, and the flocculant used for the flocculation phosphorus removal includes polyaluminum chloride, and the mass concentration ratio of the polyaluminum chloride to the total phosphorus in the denitrification carbonization liquid is (10-20):1.

[0022] Preferably, the resin comprises a non-polar resin, and the mass ratio of the non-polar resin to the COD in the dephosphorization carbonization liquid is (10-25):1; the mass concentration ratio of the non-polar resin to the COD in the dephosphorization carbonization liquid is (10-25):1;

[0023] The non-polar resin has a diameter of 0.3-1.25 mm and an average pore size of 9.0-11.0 nm.

[0024] On the other hand, the present invention also provides a system for the treatment method of the above-mentioned sludge hydrothermal carbonized liquid, including a sedimentation and regulating tank, an upflow anaerobic sludge blanket reactor, an internal circulation anaerobic reactor, a multi-stage anaerobic-aerobic denitrification tank, a secondary sedimentation tank, a high-efficiency sedimentation tank and a resin adsorption tank connected in sequence.

[0025] The present invention has the following beneficial effects:

[0026] The present invention firstly adopts hydrolysis and acidification reaction to treat organic nitrogen and difficult-to-degrade pollutants in sludge hydrothermal carbonization liquid, then performs methanogenesis reaction to achieve preliminary treatment of high-concentration COD, and then adopts multi-stage anaerobic-aerobic denitrification treatment to achieve efficient removal of COD and nitrogen, and then further reduces suspended matter, particulate COD and phosphorus through chemical phosphorus removal and multi-stage anaerobic-aerobic denitrification treatment, and finally further reduces COD in wastewater through resin adsorption to ensure that effluent requirements are met.

[0027] The method for treating sludge hydrothermal carbonized liquid provided by the present invention combines hydrolysis acidification reaction, methanogenesis reaction, multi-stage anaerobic-aerobic denitrification treatment, phosphorus removal and resin adsorption treatment to obtain a specific sludge hydrothermal carbonized liquid treatment process, which can effectively remove a large amount of organic matter and nitrogen and phosphorus compounds contained in the sludge hydrothermal carbonized liquid. The concentrations of various pollutants in the discharged water quality meet the water quality standard for sewage discharge into urban sewers GBT 31962-2015, thereby solving the problem of secondary pollution of the environment caused by wastewater generated by the sludge hydrothermal carbonization technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and other objects, features and advantages of the present invention will be apparent from the following description of preferred embodiments and accompanying drawings which illustrate the subject matter of the present invention and its use, in which:

[0029] Figure 1 A schematic diagram of a treatment system for sludge hydrothermal carbonization liquid provided by the present invention. DETAILED DESCRIPTION

[0030] The present invention will be described below by specific embodiments, and it will be appreciated by those skilled in the art that the following specific embodiments are only for illustrative purposes, and do not limit the scope of the present invention in any way. In addition, in the following embodiments, unless otherwise specified, the reagents and equipment used are all commercially available. If in the following embodiments, specific treatment conditions and treatment methods are not clearly described, then conditions and methods known in the art can be adopted to process.

[0031] The present invention provides a method for treating sludge hydrothermal carbonization liquid, comprising the following steps:

[0032] (1) adjusting the pH of the sludge hydrothermal carbonized liquid to 5-6 to obtain a primary carbonized liquid;

[0033] (2) subjecting the initially adjusted carbonized liquid to a hydrolysis and acidification reaction to obtain a hydrolysis and acidification carbonized liquid;

[0034] (3) subjecting the hydrolyzed and acidified carbonized liquid to a methanogenic reaction to obtain an anaerobic digested carbonized liquid;

[0035] (4) subjecting the anaerobic digestion carbonized liquid to a multi-stage anaerobic-aerobic denitrification treatment to obtain a denitrified carbonized liquid;

[0036] (5) removing phosphorus from the denitrified carbonized liquid to obtain a dephosphorized carbonized liquid;

[0037] (6) The dephosphorization carbonization liquid is discharged after being adsorbed by resin.

[0038] The present invention firstly adjusts the pH of the sludge hydrothermal carbonized liquid to 5-6 to obtain the initially adjusted carbonized liquid.

[0039] In some embodiments of the present invention, the process of adjusting the pH of the sludge hydrothermal carbonized liquid is carried out in a sedimentation adjustment tank; in the subsequent hydrolysis and acidification reaction, the process of converting organic nitrogen into ammonia nitrogen will produce alkalinity, and adjusting the pH of the sludge hydrothermal carbonized liquid to 5-6 can ensure that the pH of the reaction system is 5.5-6.5 during the hydrolysis and acidification reaction, so as to facilitate the hydrolysis and acidification reaction. Moreover, by adding alkali to adjust the pH once in the sedimentation adjustment tank, the pH value of the hydrolysis and acidification reaction stage can be maintained at 5.5-6.5, the pH value of the methanogenesis reaction stage can be maintained at 6-7.5, the pH value of the multi-stage anaerobic-aerobic denitrification treatment stage can be maintained at about 7, and the pH value of the phosphorus removal and resin adsorption stage can also be maintained at about 7. The pH value requirements of each stage can be met through a single alkali addition process.

[0040] In some embodiments of the present invention, the pH is adjusted by adding an alkaline agent, wherein the alkaline agent includes at least one of sodium hydroxide, sodium carbonate and waste alkali, wherein the waste alkali is an alkaline waste product (containing impurities) in a factory (such as petroleum, papermaking, electroplating and other industries).

[0041] In some embodiments of the present invention, the pH adjustment range of the sludge hydrothermal carbonization liquid is small, the dosage of the alkaline reagent is low, and the alkaline reagent itself is less affected by impurities, so the treatment cost can be saved by adding waste alkali.

[0042] After obtaining the initially adjusted carbonized liquid, the present invention performs a hydrolysis and acidification reaction on the initially adjusted carbonized liquid to obtain a hydrolyzed and acidified carbonized liquid.

[0043] In some embodiments of the present invention, the hydrolysis and acidification reaction can convert the macromolecular refractory organic matter in the sludge hydrothermal carbonization liquid into small molecular organic acids, thereby improving the subsequent COD degradation efficiency. In addition, the organic nitrogen in the sludge hydrothermal carbonization liquid can be converted into ammonia nitrogen, thereby achieving the subsequent generation of NH4 in the multi-stage anaerobic-aerobic denitrification tank. + →NO 3- →N2 denitrification process. This step can convert more than 80% of organic nitrogen into ammonia nitrogen and increase the concentration of total volatile fatty acids (TVFAs) by more than 75%.

[0044] In some embodiments of the present invention, the hydrolysis and acidification reaction is carried out in an upflow anaerobic sludge blanket reactor (UASB reactor), and the sludge inoculated in the upflow anaerobic sludge blanket reactor includes leachate sludge, and the inoculation concentration is preferably 10-20 g / L, specifically 10 g / L, 15 g / L, 16 g / L, 17 g / L, 20 g / L; the hydraulic retention time of the hydrolysis and acidification reaction is preferably 8-24 h, specifically 8 h, 12 h, 16 h, 18 h, 24 h; the temperature is preferably 25-45 ° C, specifically 25 ° C, 30 ° C, 35 ° C, 40 ° C, 45 ° C; the pH is preferably 5.5-6.5, specifically 5.5, 6.0, 6.5.

[0045] In some embodiments of the present invention, the landfill leachate sludge is selected as the inoculum sludge for the hydrolysis and acidification reaction, and the inoculum concentration is calculated according to the volume of the UASB reactor.

[0046] In some embodiments of the present invention, the pollutant properties of the landfill leachate and the sludge hydrothermal carbonization liquid in the present invention are similar, so the microorganisms in the landfill leachate sludge can quickly adapt to the water quality environment in the sludge hydrothermal carbonization liquid, reducing the acclimatization start-up time. The start-up process of the upflow anaerobic sludge blanket reactor is greatly shortened, the conversion rate of organic nitrogen is increased, and the time of the hydrolysis acidification reaction is shortened.

[0047] In some embodiments of the present invention, an organic nitrogen enhanced treatment bacterial agent is added to the hydrolysis and acidification reaction, and the inoculation amount is preferably 0.15%-0.25% of the volume of the upflow anaerobic sludge blanket reactor, specifically 0.15%, 0.2%, or 0.25%.

[0048] In some embodiments of the present invention, the organic nitrogen enhanced treatment bacterial agent includes Sonora Desert Bacillus and / or Clostridium. Preferably, the organic nitrogen enhanced treatment bacterial agent is Sonora Desert Bacillus and Clostridium with an inoculation ratio of 1:1.

[0049] In some embodiments of the present invention, the organic nitrogen enhanced treatment bacterial agent can greatly shorten the startup process of the upflow anaerobic sludge blanket reactor and further improve the conversion rate of organic nitrogen.

[0050] After obtaining the hydrolysis-acidification carbonized liquid, the present invention subjects the hydrolysis-acidification carbonized liquid to a methanogenic reaction to obtain an anaerobic digestion carbonized liquid.

[0051] In some embodiments of the present invention, the methanogenic reaction can treat the COD of the sludge hydrothermal carbonization liquid with an efficiency of up to 90%.

[0052] In some embodiments of the present invention, the methanogenic reaction is carried out in an internal circulation anaerobic reactor (IC reactor), and the sludge inoculated in the internal circulation anaerobic reactor includes leachate sludge, and the inoculation concentration is preferably 10-30 g / L, specifically 10 g / L, 20 g / L, and 30 g / L, and the inoculation concentration is calculated according to the volume of the IC reactor; the hydraulic residence time of the methanogenic reaction is preferably 6-18 h, specifically 6 h, 12 h, and 18 h, and the temperature is preferably 25-45 ° C, specifically 25 ° C, 30 ° C, 40 ° C, and 45 ° C; the pH is preferably 6-7.5, specifically 6, 6.5, 7.0, and 7.5; the internal circulation ratio is preferably 10-20, specifically 10, 15, and 20.

[0053] The IC reactor has an internal circulation system, which can greatly increase the COD volume load of the reactor. Its organic load is about 3 times that of the upflow anaerobic sludge blanket reactor. The COD concentration in the hydrothermal carbonization liquid is high, and a process with a large volume load is required. The COD treatment efficiency of the internal circulation anaerobic reactor can reach about 90%.

[0054] After obtaining the anaerobic digestion carbonized liquid, the present invention performs multi-stage anaerobic-aerobic denitrification treatment on the anaerobic digestion carbonized liquid to obtain the denitrified carbonized liquid.

[0055] In some embodiments of the present invention, the multi-stage anaerobic-aerobic denitrification process can further remove nitrogen and COD from the sludge hydrothermal carbonization liquid.

[0056] In some embodiments of the present invention, the number of stages of the multi-stage anaerobic-aerobic denitrification treatment is preferably ≥ 2, specifically 2, 3, or 4; wherein the hydraulic retention time of each anaerobic unit is preferably 1-3 hours, specifically 1 hour, 2 hours, or 3 hours, and the hydraulic retention time of each aerobic unit is preferably 4-8 hours, specifically 4 hours, 6 hours, or 8 hours, and the internal reflux ratio is preferably 0-50%, specifically 25%, 30%, 40%, or 50%.

[0057] In some embodiments of the present invention, a multi-stage treatment method is used to carry out the nitrogen removal reaction, which can effectively reduce the concentration of nitrogen pollutants in the sludge hydrothermal carbonization liquid. In practical applications, the corresponding number of stages can be selected according to the pollutant concentration of the sludge hydrothermal carbonization liquid. In an embodiment of the present invention, the number of stages of the multi-stage anaerobic-aerobic denitrification treatment is 3.

[0058] In some embodiments of the present invention, the multi-stage anaerobic-aerobic denitrification treatment device includes a multi-stage anaerobic-aerobic denitrification tank (multi-stage A / O denitrification tank) and a secondary sedimentation tank, and the external reflux ratio of the multi-stage anaerobic-aerobic denitrification tank and the secondary sedimentation tank is preferably 50%-100%, specifically 50%, 75%, and 100%; the anaerobic digestion carbonized liquid enters the anaerobic-aerobic denitrification tank through a multi-stage water inlet method, and the water inlet ratio of each stage of anaerobic-aerobic units is independently preferably 0-50%.

[0059] In some embodiments of the present invention, the multi-stage anaerobic-aerobic denitrification tank is inoculated with sludge, and the concentration of the sludge in each anaerobic unit is independently 3000-6000 mg / L, and the concentration of the sludge in each aerobic unit is independently 3000-6000 mg / L.

[0060] In some embodiments of the present invention, the type of sludge inoculated in the multi-stage anaerobic-aerobic denitrification tank is not limited, and any type known to those skilled in the art can be used.

[0061] In some embodiments of the present invention, the multi-stage water inlet method can distribute the water quality of each stage in proportion, thereby ensuring the carbon source content of each stage, and can increase the suspended solid concentration of the mixed liquid in the reaction tank, so that the nitrate nitrogen produced in the aerobic stage can be repeatedly denitrified (NH4 + →NO3 - →N2), thus improving the denitrification efficiency.

[0062] In some embodiments of the present invention, the number of sections of the multi-stage water inlet is the same as the number of stages of the multi-stage anaerobic-aerobic denitrification tank. For example, when the number of sections of the multi-stage water inlet is 3, the number of stages of the multi-stage anaerobic-aerobic denitrification tank is also 3. At this time, in the three-stage anaerobic-aerobic denitrification tank, the water inlet ratio of each stage of the anaerobic-aerobic unit can be specifically Q1 (the water inlet ratio of the first stage anaerobic-aerobic unit) is 33.3%-50%, more specifically 33.3%, 40%, 50%; Q2 (the water inlet ratio of the second stage anaerobic-aerobic unit) is 30%-33.3%, more specifically 30%, 33.3%; Q3 (the water inlet ratio of the third stage anaerobic-aerobic unit) is 20%-33.3%, more specifically 20%, 30%, 33.3%.

[0063] After obtaining the denitrified carbonized liquid, the present invention removes phosphorus from the denitrified carbonized liquid to obtain a dephosphorized carbonized liquid.

[0064] In some embodiments of the present invention, the phosphorus removal is carried out in a high-efficiency sedimentation tank. After the sludge hydrothermal carbonization liquid is flocculated, precipitated, and filtered in the high-efficiency sedimentation tank, the concentration of suspended matter in the wastewater will be significantly reduced, and the particulate matter and phosphorus will also be significantly reduced, which can further meet the requirements of the management standard.

[0065] The present invention designs phosphorus removal to be carried out after denitrification treatment. In this way, on the one hand, the C / N / P ratio in the sludge hydrothermal carbonization liquid before the phosphorus removal step is maintained, ensuring the activity of microorganisms in the sludge. On the other hand, it avoids the poor treatment efficiency of chemical phosphorus removal for organic phosphorus, resulting in the need for secondary phosphorus removal to avoid the risk of excessive total phosphorus in the effluent. The process is relatively simple.

[0066] In some embodiments of the present invention, the phosphorus removal method includes flocculation phosphorus removal, and the flocculant used for the flocculation phosphorus removal includes polyaluminum chloride. The mass concentration ratio of the polyaluminum chloride to the total phosphorus in the denitrification carbonization liquid is preferably (10-20):1, specifically 10:1, 15:1, or 20:1.

[0067] In some embodiments of the present invention, polyaluminium chloride is selected as a flocculant, which can effectively reduce the total phosphorus content in the sludge hydrothermal carbonization liquid; at the same time, when the flocculant is used, the phosphorus removal reaction can be carried out under the condition of pH 6-9, and there is no need to adjust the pH, which saves costs and process flow.

[0068] After obtaining the dephosphorization carbonization liquid, the present invention discharges the dephosphorization carbonization liquid after resin adsorption.

[0069] In some embodiments of the present invention, the resin adsorption is performed in a resin adsorption tank. After the dephosphorus carbonization liquid is subjected to resin adsorption, the refractory substances in the sludge hydrothermal carbonization liquid can be further treated to meet the requirements of the pipe standard.

[0070] In some embodiments of the present invention, the resin is a non-polar resin, and the mass concentration ratio of the non-polar resin to the COD in the dephosphorization carbonization liquid is preferably (10-25):1, specifically 10:1, 15:1, 25:1, the diameter of the non-polar resin is preferably 0.3-1.25mm, specifically 0.3mm, 0.5mm, 1.25mm, and the average pore size is preferably 9.0-11.0nm, specifically 9.0mm, 10.0mm, 11.0mm.

[0071] In some embodiments of the present invention, the non-polar resin includes LS-100 and / or D101.

[0072] The present invention also provides Figure 1 The sludge hydrothermal carbonization liquid treatment system shown in the figure includes a sedimentation and regulating tank, an upflow anaerobic sludge blanket reactor, an internal circulation anaerobic reactor, a multi-stage anaerobic-aerobic denitrification tank, a secondary sedimentation tank, a high-efficiency sedimentation tank and a resin adsorption tank, which are connected in sequence. Among them, the number of stages of the multi-stage anaerobic-aerobic denitrification tank is 3.

[0073] The technical scheme of the present invention will be described clearly and completely below in conjunction with the accompanying drawings and embodiments. The embodiments of the present application are only used as examples, and all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0074] The sludge hydrothermal carbonization liquid treatment system used in the embodiment of the present invention is as follows Figure 1 shown.

[0075] The Sonora Desert Bacillus and Clostridium used in the following examples were purchased from Mingzhou Biotechnology.

[0076] Example 1

[0077] (1) The residual sludge hydrothermal carbonized liquid from the municipal sewage treatment plant is passed into a sedimentation adjustment tank, and sodium hydroxide is added to adjust the pH to 5 to obtain a primary carbonized liquid.

[0078] (2) The obtained initially adjusted carbonized liquid is passed into an upflow anaerobic sludge blanket reactor inoculated with landfill leachate sludge to perform a hydrolysis and acidification reaction to obtain a hydrolysis and acidification carbonized liquid. The inoculation concentration of the landfill leachate sludge is 15 g / L, the hydraulic retention time is 8 h, the temperature is 25° C., and the pH is 5.5.

[0079] (3) The obtained hydrolyzed acidified carbonized liquid is passed into an internal circulation anaerobic reactor inoculated with landfill leachate sludge to produce methanogens, thereby obtaining anaerobic digested carbonized liquid. The inoculation concentration of the landfill leachate sludge is 20 g / L, the hydraulic retention time is 6 h, the temperature is 25° C., the pH is controlled at 6.5, and the internal circulation ratio is 10.

[0080] (4) The obtained anaerobic digestion carbonized liquid is introduced into a three-stage anaerobic-aerobic denitrification tank through a three-stage water inlet method for denitrification. The inlet ratios Q1, Q2, and Q3 are 50%, 30%, and 20%, and the internal reflux ratio is 25%. In the three-stage anaerobic-aerobic denitrification tank, the hydraulic retention time of each anaerobic unit is 1 hour, and the hydraulic retention time of the aerobic unit is 4 hours. The denitrified wastewater in the three-stage anaerobic-aerobic denitrification tank is discharged into the secondary sedimentation tank to obtain a denitrified carbonized liquid. The external reflux ratio between the three-stage anaerobic-aerobic denitrification tank and the secondary sedimentation tank is 50%.

[0081] (5) The denitrified carbonized liquid is discharged into a high-efficiency sedimentation tank, polyaluminium chloride is added to remove phosphorus (the mass concentration ratio of polyaluminium chloride to total phosphorus in the denitrified carbonized liquid is 10:1), and after precipitation and filtration, a dephosphorized carbonized liquid is obtained.

[0082] (6) The dephosphorization carbonization liquid is discharged into a resin adsorption tank, wherein the resin adsorption tank is filled with a non-polar resin LS-100 with a particle diameter of 0.5 mm and an average pore size of 10.0 nm, and the mass concentration ratio of the non-polar resin to the COD in the dephosphorization carbonization liquid is 10:1.

[0083] The effluent quality of each stage of treatment in Example 1 was tested. Among them, COD, ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, total nitrogen and total phosphorus were tested according to the test method in "Water and Wastewater Monitoring and Analysis Methods" (4th edition [M]. Beijing: China Environmental Science Press, 2002.); organic nitrogen concentration was determined by subtracting inorganic nitrogen (ammonia nitrogen, nitrite nitrogen, nitrate nitrogen) from total nitrogen; TVFAs were tested according to the test method in "Routine Analysis of Biogas Fermentation" ([M]. Beijing Science and Technology Press, 1984.) of Chengdu Institute of Biology, Chinese Academy of Sciences. The results are shown in Table 1.

[0084] Table 1 Water quality of effluent at each treatment stage of Example 1

[0085]

[0086] From the data of hydrolysis acidification carbonization liquid in Table 1, it can be seen that the hydrolysis acidification process can convert more than 80% of organic nitrogen into ammonia nitrogen, and the degradation rate of total volatile fatty acids (TVFAs) reaches more than 75%. From the data of anaerobic digestion carbonization liquid, it can be seen that the methanogenic reaction can effectively remove COD in the sludge hydrothermal carbonization liquid, and the removal rate is as high as 90%.

[0087] Example 2

[0088] (1) The hydrothermal carbonized liquid of the residual sludge from the brewery wastewater treatment plant is passed into a sedimentation adjustment tank, and sodium hydroxide is added to adjust the pH to 5.5 to obtain a primary carbonized liquid.

[0089] (2) The obtained initially adjusted carbonized liquid is passed into an upflow anaerobic sludge blanket reactor inoculated with landfill leachate sludge to perform a hydrolysis and acidification reaction to obtain a hydrolysis and acidification carbonized liquid. The inoculation concentration of the landfill leachate sludge is 15 g / L, the hydraulic retention time is 16 h, the temperature is 30° C., and the pH is 6.

[0090] (3) The obtained hydrolyzed acidified carbonized liquid is passed into an internal circulation anaerobic reactor inoculated with landfill leachate sludge to produce methanogens, thereby obtaining anaerobic digested carbonized liquid. The inoculation concentration of the landfill leachate sludge is 20 g / L, the hydraulic retention time is 12 h, the temperature is 30° C., the pH is controlled at 7, and the internal circulation ratio is 15.

[0091] (4) The obtained anaerobic digestion carbonized liquid is introduced into a three-stage anaerobic-aerobic denitrification tank through a three-stage water inlet method for denitrification. The inlet ratios Q1, Q2, and Q3 are 40%, 30%, and 30%, and the internal reflux ratio is 50%. In the three-stage anaerobic-aerobic denitrification tank, the hydraulic retention time of each anaerobic unit is 1 hour, and the hydraulic retention time of the aerobic unit is 4 hours. The denitrified wastewater in the three-stage anaerobic-aerobic denitrification tank is discharged into the secondary sedimentation tank to obtain a denitrified carbonized liquid. The external reflux ratio of the three-stage anaerobic-aerobic denitrification tank to the secondary sedimentation tank is 75%.

[0092] (5) The denitrified carbonized liquid is discharged into a high-efficiency sedimentation tank, polyaluminium chloride is added to remove phosphorus (the mass concentration ratio of polyaluminium chloride to total phosphorus in the denitrified carbonized liquid is 15:1), and after precipitation and filtration, a dephosphorized carbonized liquid is obtained.

[0093] (6) The dephosphorization carbonization liquid is discharged into a resin adsorption tank, wherein the resin adsorption tank is filled with a non-polar resin D101 with a particle diameter of 0.5 mm and an average pore size of 10.0 nm, and the mass concentration ratio of the non-polar resin to the COD in the dephosphorization carbonization liquid is 25:1.

[0094] Example 3

[0095] (1) The hydrothermal carbonized liquid of the excess sludge from the pharmaceutical wastewater treatment plant is passed into a sedimentation adjustment tank, and sodium hydroxide is added to adjust the pH to 6 to obtain a primary carbonized liquid.

[0096] (2) The obtained initially adjusted carbonized liquid is passed into an upflow anaerobic sludge blanket reactor inoculated with landfill leachate sludge and organic nitrogen enhanced treatment bacterial agent to perform a hydrolysis and acidification reaction to obtain a hydrolysis and acidification carbonized liquid. The inoculation concentration of the landfill leachate sludge is 20 g / L, and the inoculation amount of the organic nitrogen enhanced treatment bacterial agent (the ratio of Sonora Desert Bacillus and Clostridium is 1:1) is 0.2% of the volume of the upflow anaerobic sludge blanket reactor. The hydraulic retention time is 24 h, the temperature is 45° C., and the pH is 6.5.

[0097] (3) The obtained hydrolyzed acidified carbonized liquid is passed into an internal circulation anaerobic reactor inoculated with landfill leachate sludge to produce methanogens, thereby obtaining anaerobic digested carbonized liquid. The inoculation concentration of the landfill leachate sludge is 30 g / L, the hydraulic retention time is 18 h, the temperature is 45° C., the pH is controlled at 7.5, and the internal circulation ratio is 20.

[0098] (4) The obtained anaerobic digestion carbonized liquid is passed through a three-stage water inlet method into a three-stage anaerobic-aerobic denitrification tank for denitrification. The inlet ratios Q1, Q2, and Q3 are 33.3%, 33.3%, and 33.3%, and the internal reflux ratio is 50%. In the three-stage anaerobic-aerobic denitrification tank, the hydraulic retention time of each anaerobic unit is 3 hours, and the hydraulic retention time of the aerobic unit is 8 hours. The denitrified wastewater in the three-stage anaerobic-aerobic denitrification tank is discharged into the secondary sedimentation tank to obtain a denitrified carbonized liquid. The external reflux ratio of the three-stage anaerobic-aerobic denitrification tank and the secondary sedimentation tank is 100%.

[0099] (5) The denitrified carbonized liquid is discharged into a high-efficiency sedimentation tank, polyaluminium chloride is added to remove phosphorus (the mass concentration ratio of polyaluminium chloride to total phosphorus in the denitrified carbonized liquid is 20:1), and after precipitation and filtration, a dephosphorized carbonized liquid is obtained.

[0100] (6) The dephosphorization carbonization liquid is discharged into a resin adsorption tank, wherein the resin adsorption tank is filled with a non-polar resin LS-100 with a particle diameter of 0.5 mm and an average pore size of 10.0 nm. The mass concentration ratio of the non-polar resin to the COD in the dephosphorization carbonization liquid is 15:1.

[0101] Comparative Example

[0102] (1) The residual sludge hydrothermal carbonized liquid from the municipal sewage treatment plant is passed into a sedimentation adjustment tank, sodium hydroxide is added to adjust the pH to 7, polyaluminium chloride is added to remove phosphorus (the mass concentration ratio of polyaluminium chloride to the total phosphorus in the residual sludge hydrothermal carbonized liquid from the municipal sewage treatment plant is 10:1), and after precipitation and filtration, a primary adjusted dephosphorization carbonized liquid is obtained.

[0103] (2) The pH of the obtained primary phosphorus removal carbonized liquid is adjusted to 5.5, and passed into an upflow anaerobic sludge blanket reactor inoculated with landfill leachate sludge to perform a hydrolysis and acidification reaction to obtain a hydrolysis and acidification carbonized liquid. The inoculation concentration of the landfill leachate sludge is 15 g / L, the hydraulic retention time is 8 h, and the temperature is 25°C.

[0104] (3) The obtained hydrolyzed acidified carbonized liquid is passed into an internal circulation anaerobic reactor inoculated with landfill leachate sludge to produce methanogens, thereby obtaining anaerobic digested carbonized liquid. The inoculation concentration of the landfill leachate sludge is 20 g / L, the hydraulic retention time is 6 h, the temperature is 25° C., the pH is controlled at 6.5, and the internal circulation ratio is 10.

[0105] (4) The obtained anaerobic digestion carbonized liquid is introduced into a three-stage anaerobic-aerobic denitrification tank through a three-stage water inlet method for denitrification. The inlet ratios Q1, Q2, and Q3 are 50%, 30%, and 20%, and the internal reflux ratio is 25%. In the three-stage anaerobic-aerobic denitrification tank, the hydraulic retention time of each anaerobic unit is 1 hour, and the hydraulic retention time of the aerobic unit is 4 hours. The denitrified wastewater in the three-stage anaerobic-aerobic denitrification tank is discharged into the secondary sedimentation tank to obtain a denitrified carbonized liquid. The external reflux ratio between the three-stage anaerobic-aerobic denitrification tank and the secondary sedimentation tank is 50%.

[0106] (5) The dephosphorization carbonization liquid is discharged into a resin adsorption tank, wherein the resin adsorption tank is filled with a non-polar resin LS-100 with a particle diameter of 0.5 mm and an average pore size of 10.0 nm, wherein the mass concentration ratio of the non-polar resin LS-100 to the COD in the denitrification liquid is 10:1.

[0107] The water quality of the effluent treated at each stage of the comparative example was tested, and the testing method was the same as that in Table 1. The results are shown in Table 2.

[0108] Table 2 Water quality of effluent at each treatment stage of comparative example 1

[0109]

[0110] From the data of hydrolysis acidified carbonized liquid in Table 2, it can be seen that chemical phosphorus removal is performed first, and a large amount of dosage is required (from the data in Table 2, the total phosphorus content of the sludge hydrothermal carbonized liquid remaining in the municipal sewage treatment plant is 95 mg / L, and polyaluminum chloride is added according to a mass concentration ratio of 10:1, and the amount of polyaluminum chloride added is 950 mg / L). In addition, since organic phosphorus is difficult to degrade by chemical phosphorus removal, the treatment efficiency is also poor, resulting in the effluent total phosphorus (TP) failing to meet the standard requirement of 8 mg / L.

[0111] According to the comparison of the data in Table 1 and Table 2, the sludge hydrothermal carbonization liquid treatment method provided by the present invention has a simple process. After adjusting the pH in step (1), there is no need to add acid or alkaline reagents. The pH generated during the reaction of each step can keep the pH of the effluent stable at about 7, and the acid and alkali cost is relatively lower. In addition, the phosphorus removal process is set after the denitrification reaction, which reduces the input amount of flocculant and ensures that the total phosphorus in the effluent meets the urban sewer water quality standard GBT31962-2015.

[0112] The concentration of pollutants in the water quality of test examples 1-3 when entering (not treated by the sludge hydrothermal carbonization liquid treatment method) and the concentration of pollutants in the discharged water quality when discharged (after being treated by the sludge hydrothermal carbonization liquid treatment method) are shown in Table 3.

[0113] Table 3 Test results

[0114]

[0115] It can be seen from Table 3 that the sludge hydrothermal carbonization liquid treatment method provided by the present application can effectively remove a large amount of organic matter and nitrogen and phosphorus compounds contained in the sludge hydrothermal carbonization liquid. The concentration of each pollutant in the discharged water quality meets the water quality standard for sewage discharged into urban sewers GBT 31962-2015.

[0116] While preferred embodiments of the present invention have been shown and described, it is contemplated that those skilled in the art may devise various modifications of the present invention within the spirit and scope of the appended claims.

Claims

1. A method for treating sludge hydrothermal carbonization liquid, characterized in that: The steps include: (1) adjusting the pH of the sludge hydrothermal carbonized liquid to 5-6 to obtain a primary carbonized liquid; (2) subjecting the initially adjusted carbonized liquid to a hydrolysis and acidification reaction to obtain a hydrolysis and acidification carbonized liquid; (3) subjecting the hydrolyzed and acidified carbonized liquid to a methanogenic reaction to obtain an anaerobic digested carbonized liquid; (4) subjecting the anaerobic digestion carbonized liquid to a multi-stage anaerobic-aerobic denitrification treatment to obtain a denitrified carbonized liquid; (5) removing phosphorus from the denitrified carbonized liquid to obtain a dephosphorized carbonized liquid; (6) The dephosphorization carbonization liquid is discharged after being adsorbed by resin.

2. The processing method according to claim 1, characterized in that: The hydrolysis and acidification reaction is carried out in an upflow anaerobic sludge blanket reactor, wherein the sludge inoculated in the upflow anaerobic sludge blanket reactor includes landfill leachate sludge, and the inoculation concentration is 10-20 g / L; The hydraulic retention time of the hydrolysis and acidification reaction is 8-24 hours, the temperature is 25-45° C., and the pH is 5.5-6.

5.

3. The processing method according to claim 2, characterized in that: An organic nitrogen strengthening treatment bacterial agent is added to the hydrolysis and acidification reaction, and the inoculation amount is 0.15%-0.25% of the volume of the upflow anaerobic sludge blanket reactor.

4. The processing method according to claim 3, characterized in that: The organic nitrogen enhanced treatment bacterial agent includes Sonora Desert Bacillus and / or Clostridium.

5. The processing method according to claim 1, characterized in that: The methanogenic reaction is carried out in an internal circulation anaerobic reactor, and the sludge inoculated in the internal circulation anaerobic reactor includes landfill leachate sludge, and the inoculation concentration is 10-30 g / L; The hydraulic retention time of the methanogenic reaction is 6-18 hours, the temperature is 25-45° C., the pH is 6-7.5, and the internal circulation ratio is 10-20.

6. The processing method according to claim 1, characterized in that: The number of stages of the multi-stage anaerobic-aerobic denitrification treatment is ≥2, wherein the hydraulic retention time of each anaerobic unit is 1-3 hours, the hydraulic retention time of each aerobic unit is 4-8 hours, and the internal reflow ratio is 0-50%.

7. The processing method according to claim 1 or 6, characterized in that: The multi-stage anaerobic-aerobic denitrification treatment device comprises a multi-stage anaerobic-aerobic denitrification tank and a secondary sedimentation tank, and the external reflow ratio of the multi-stage anaerobic-aerobic denitrification tank to the secondary sedimentation tank is 50-100%; The anaerobic digestion carbonized liquid enters the multi-stage anaerobic-aerobic denitrification tank through a multi-stage water inlet mode, and the water inlet ratio of each stage of the anaerobic-aerobic unit is independently 0-50%.

8. The processing method according to claim 1, characterized in that: The phosphorus removal method includes flocculation phosphorus removal, and the flocculant used in the flocculation phosphorus removal includes polyaluminum chloride. The mass concentration ratio of the polyaluminum chloride to the total phosphorus in the denitrification carbonization liquid is (10-20):

1.

9. The processing method according to claim 1, characterized in that: The resin includes a non-polar resin, and the mass concentration ratio of the non-polar resin to the COD in the dephosphorization carbonization liquid is (10-25):1; The non-polar resin has a diameter of 0.3-1.25 mm and an average pore size of 9.0-11.0 nm.

10. A system for implementing the treatment method described in any one of claims 1 to 9, comprising a sedimentation and regulating tank, an upflow anaerobic sludge blanket reactor, an internal circulation anaerobic reactor, a multi-stage anaerobic-aerobic denitrification tank, a secondary sedimentation tank, a high-efficiency sedimentation tank and a resin adsorption tank connected in sequence.

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