Environment-friendly treatment process for explosive wastewater

Abstract

The invention relates to an explosive wastewater green treatment process which comprises the following steps: S1, a pretreatment stage: pumping collected explosive wastewater into a micro-nano air flotation device to remove suspended solids, oils and surfactants in the explosive wastewater; s2, a resin adsorption stage: pumping the pretreated explosive wastewater into a resin adsorption system, and selectively adsorbing and removing ammonia nitrogen pollutants in the wastewater through resin; s3, a regeneration and desorption stage: carrying out sleeve washing and regeneration and desorption on the resin subjected to adsorption saturation by adopting dilute nitric acid so as to desorb and separate ammonia nitrogen adsorbed in the resin; and S4, a product recycling stage: carrying out impurity removal treatment on a concentrated regeneration desorption solution generated by desorption, and then adjusting the pH value to obtain an ammonium nitrate solution which is recycled in an explosive production process. And S5, a waste liquid treatment stage: adjusting the pH value of the resin adsorption effluent, and conveying the resin adsorption effluent to a sewage station for combined treatment. According to the method, the ammonia nitrogen pollutants in the explosive wastewater can be removed, and meanwhile explosive production raw materials can be recycled.

Description

Technical Field

[0001] The present invention belongs to the technical field of explosive wastewater treatment, and particularly relates to a green treatment process for explosive wastewater. Background Art

[0002] At present, in the production process of industrial detonators, industrial explosives and other series of products, corresponding explosive wastewater will be generated. The main raw materials for explosive production are ammonium nitrate, sodium nitrate, etc.; and the explosive wastewater mainly comes from the flushing process of production equipment, storage tanks, product packaging and other processes. The types of pollutants in the wastewater are relatively simple, and the main pollutants are ammonia nitrogen (ammonium nitrate) and oils. Since the ammonia nitrogen concentration in the explosive wastewater is very high, exceeding the acceptable range of the biochemical system, if directly discharged into the sewage treatment station, it will cause the collapse of the biochemical system and cannot achieve stable discharge up to the standard. Therefore, it is necessary to pre-treat the explosive production wastewater to reduce the ammonia nitrogen concentration in the explosive wastewater so that it meets the ammonia nitrogen requirement of the influent of the biochemical system.

[0003] However, traditional high ammonia nitrogen pre-treatment processes such as stripping method, sulfuric acid evaporation crystallization method, etc. consume a large amount of reagents and energy while converting ammonia nitrogen into hazardous waste, resulting in high operating costs and hazardous waste disposal costs. Therefore, those skilled in the art are committed to providing a green treatment process for explosive wastewater that can recover explosive production raw materials (ammonium nitrate) while removing ammonia nitrogen pollutants in the explosive wastewater. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention provides a green treatment process for explosive wastewater, and the specific technical solutions are as follows:

[0005] The present invention provides a green treatment process for explosive wastewater, which comprises the following steps:

[0006] Step S1, pre-treatment stage: Pump the collected explosive wastewater into a micro-nano air flotation device to remove suspended solids, oils and surfactants in the explosive wastewater;

[0007] Step S2, resin adsorption stage: Pump the pre-treated explosive wastewater into a resin adsorption system, and selectively adsorb and remove ammonia nitrogen pollutants in the wastewater through the resin. In this stage, resin adsorption effluent with ammonia nitrogen removed by adsorption is generated;

[0008] Step S3, regeneration and desorption stage: Use dilute nitric acid to wash and regenerate and desorb the saturated resin to desorb and separate the ammonia nitrogen adsorbed in the resin. In this stage, concentrated regeneration and desorption liquid is generated by desorption;

[0009] Step S4, product reuse stage: Adjust the pH value of the concentrated regeneration and desorption liquid generated by desorption after impurity removal treatment to obtain ammonium nitrate solution for reuse in the explosive production process;

[0010] Step S5, waste liquid treatment stage: after adjusting the pH value of the resin adsorbed water, it is transported to the sewage station for combined treatment to ensure that the discharge meets the standards.

[0011] As a preferred technical solution of the present invention, in step S1, the wastewater pretreated by the micro-nano flotation device is pumped into a high-efficiency condensation oil remover and a primary organic separator for treatment in sequence to remove residual oily pollutants, partially soluble macromolecular organic matter and suspended matter in the wastewater; and then treated by a precision filter to remove micron-sized suspended matter in the wastewater.

[0012] As a preferred technical solution of the present invention, in step S2, the resin adsorption system is a three-stage resin adsorption column, and the resin used in the resin adsorption column is an ammonium ion specific adsorption resin.

[0013] As a preferred technical solution of the present invention, in step S3, the dilute nitric acid washing regeneration analysis is divided into two stages, the first stage uses the circulating regeneration liquid for analysis, and the second stage uses the newly prepared dilute nitric acid solution for analysis.

[0014] As a preferred technical solution of the present invention, the first stage uses the dilute regeneration analysis liquid produced by the previous dilute nitric acid regeneration analysis to regenerate the resin bed. The concentrated regeneration analysis liquid produced by this stage of regeneration analysis is stored in an ammonium nitrate solution storage tank after removing residual organic matter through a secondary organic separator, and after adjusting the pH value to 7.0-8.0 with a sodium hydroxide solution, it is returned to the dissolution process of the explosive production line.

[0015] As a preferred technical solution of the present invention, the second stage uses a newly prepared 8% dilute nitric acid solution to continue regenerating and analyzing the resin bed. The dilute regeneration analysis solution generated in this stage is stored in a dilute nitric acid wash tank for use in the next regeneration analysis of the adsorption saturated resin column.

[0016] As a preferred technical solution of the present invention, the analytical solution produced in the first stage is a mixed solution of dilute nitric acid and ammonium nitrate with a content of 3% to 5%.

[0017] As a preferred technical solution of the present invention, the resin adsorption effluent produced in step S2 is transported to an effluent collection tank, and after adjusting the pH value to 7.0-9.0 with sodium hydroxide solution, it is transported to a sewage station for combined treatment to ensure that the discharge meets the standards.

[0018] As a preferred technical solution of the present invention, the resin bed that has completed acid regeneration and analysis is subjected to compressed air to press out the dilute nitric acid remaining in the resin bed, and then the resin bed is washed with soft water to clean out the bound water in the resin micropores. After the washing is completed, the resin column is ready for use and enters the next adsorption cycle. This process generates resin regeneration flushing wastewater.

[0019] As a preferred technical solution of the present invention, the high-efficiency coagulation oil separator, the first-stage organic matter separator, and the second-stage organic matter separator are regularly subjected to gas-water combined backwashing to discharge the suspended solids, oils, and organic matters intercepted therein; and the backwashing wastewater and the resin regeneration rinsing wastewater are transported to the backwashing water collection tank, and after adjusting the pH value to 7.0 - 9.0 with sodium hydroxide solution, they are transported to the sewage treatment station for combined treatment to ensure up-to-standard discharge.

[0020] The beneficial effects of the present invention are as follows:

[0021] 1. The green treatment process for explosive wastewater of the present invention can separate and concentrate ammonium nitrate from the wastewater, and by removing other pollution factors such as oils and suspended solids in the wastewater, obtain ammonium nitrate solution that meets the production requirements, so as to recover the explosive production raw material (ammonium nitrate) while removing ammonia nitrogen pollutants in the explosive wastewater.

[0022] 2. In the green treatment process for explosive wastewater of the present invention, the ammonium ion-specific adsorption resin is the main body of the ammonium nitrate recovery process; the explosive wastewater after micro-nano air flotation and filtration treatment is introduced into the resin adsorption system, and by utilizing the porosity and cross-linking of the ion exchange resin, the ammonia nitrogen in the wastewater is selectively adsorbed in the resin through ion exchange, and other substances in the wastewater are retained in the water, thereby realizing the separation and enrichment of ammonia nitrogen in the wastewater. The ammonia nitrogen concentration of the wastewater after resin treatment is significantly reduced, which can meet the influent requirements of the ammonia nitrogen for the biochemical sewage treatment system, and can enter the sewage treatment station for mixed treatment and discharge with domestic sewage.

[0023] 3. In the green treatment process for explosive wastewater of the present invention, when the resin adsorption exchange capacity reaches saturation, the resin is desorbed and regenerated with 8% dilute nitric acid solution, so that the ammonia nitrogen adsorbed in the resin is desorbed in the form of ammonium nitrate solution; the dilute nitric acid and ammonium nitrate mixed solution with a content of 3% - 5% generated by desorption can be recycled to the dissolution process of the solid raw materials for explosive production; the ammonium nitrate recovery process can significantly reduce the operation energy consumption and the generation amount of hazardous waste, and at the same time recover the explosive production raw materials in the wastewater, realizing "turning waste into treasure". BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The process flow diagram of the green treatment process for explosive wastewater of the present invention is shown. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] In order to make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0026] The embodiment of the present invention provides a green treatment process for explosive wastewater, so as to remove ammonia nitrogen pollutants in the explosive wastewater and recover the raw material (ammonium nitrate) for explosive production at the same time.

[0027] The technical solution in the embodiment of the present invention is to solve the above problems, and the overall idea is as follows: the present invention uses ammonium ion specific adsorption resin as the main body of the ammonium nitrate recovery process; the explosive wastewater after micro-nano flotation and filtration treatment is passed into the resin adsorption system, and the porosity and cross-linking of the ion exchange resin are utilized to selectively adsorb the ammonia nitrogen in the wastewater into the resin through ion exchange, and other substances in the wastewater are retained in the water, thereby realizing the separation and enrichment of ammonia nitrogen in the wastewater. The ammonia nitrogen concentration of the wastewater treated with the resin is significantly reduced, which can meet the water inlet requirements of the biochemical sewage treatment system for ammonia nitrogen, and can enter the sewage treatment station and be mixed with domestic sewage for treatment and discharge.

[0028] In the present invention, when the resin adsorption exchange capacity reaches saturation, the resin is regenerated by decomposing it with an 8% dilute nitric acid solution, so that the ammonia nitrogen adsorbed in the resin is decomposed in the form of ammonium nitrate solution; the decomposition produces a mixed solution of dilute nitric acid and ammonium nitrate with a content of 3% to 5%, which can be reused in the dissolving process of solid raw materials in explosive production.

[0029] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0030] Combination Figure 1 As shown, a green treatment process for explosive wastewater includes the following steps:

[0031] Step S1, pretreatment stage: pumping the collected explosive wastewater into a micro-nano flotation device to remove suspended matter, oil and surfactant in the explosive wastewater;

[0032] Step S2, resin adsorption stage: the pre-treated explosive wastewater is pumped into the resin adsorption system, and the ammonia nitrogen pollutants in the wastewater are removed by resin selective adsorption. In this stage, resin adsorption effluent with ammonia nitrogen removed is produced;

[0033] Step S3, regeneration and analysis stage: the saturated resin is washed with dilute nitric acid for regeneration and analysis to separate the ammonia nitrogen adsorbed in the resin. This stage of analysis produces a concentrated regeneration and analysis solution;

[0034] Step S4, product recycling stage: the concentrated regenerated analytical solution produced by the analysis is treated to remove impurities and then the pH value is adjusted to obtain an ammonium nitrate solution which is recycled to the explosive production process;

[0035] Step S5, waste liquid treatment stage: after adjusting the pH value of the resin adsorbed water, it is transported to the sewage station for combined treatment to ensure that the discharge meets the standards.

[0036] By adopting the above technical solutions, the green treatment process for explosive wastewater can separate and concentrate ammonium nitrate from the wastewater, and by removing other pollution factors such as oils and suspended solids in the wastewater, an ammonium nitrate solution meeting the production requirements can be obtained, so as to realize the recovery of the raw material (ammonium nitrate) for explosive production while removing ammonia nitrogen pollutants in the water; the ammonium nitrate recovery process can significantly reduce the operating energy consumption and the generation amount of hazardous waste, and at the same time recover the raw materials for explosive production in the wastewater, realizing "turning waste into treasure".

[0037] In the present invention, the micro-nano air flotation device adopted is an efficient solid-liquid separation equipment in wastewater treatment, and its core function is to achieve efficient removal of pollutants by generating micron / nano-scale bubbles. Micro-nano bubbles have a larger specific surface area and stronger surface adsorption ability, and can efficiently capture emulsified oils, suspended particles and surfactants in the wastewater, avoiding the subsequent resin being blocked by oil stains and ensuring the resin adsorption efficiency.

[0038] The traditional dilute sulfuric acid resin regeneration and desorption process needs to add process equipment for the crystallization part of ammonium sulfate solution. Therefore, the one-time investment of the traditional dilute sulfuric acid desorption process is higher than that of the dilute nitric acid desorption process, and the ammonium sulfate solution needs to be evaporated and crystallized, which further leads to a relatively high electricity cost for this process; the traditional dilute sulfuric acid desorption process converts the ammonia nitrogen in the explosive wastewater into ammonium sulfate, and ammonium sulfate cannot be reused in the explosive production line, while the dilute nitric acid desorption process of the present invention converts the ammonia nitrogen in the main wastewater into ammonium nitrate, and ammonium nitrate can be reused in the explosive production line. Therefore, the traditional dilute sulfuric acid desorption process will generate more hazardous waste disposal costs than the dilute nitric acid desorption process.

[0039] The following Table 1 and Table 2 respectively compare and show the operating costs of the dilute nitric acid resin regeneration and desorption process of the present invention and the traditional dilute sulfuric acid resin regeneration and desorption process:

[0040] Table 1 List of operating costs of the dilute nitric acid resin regeneration and desorption process

[0041]

[0042] Table 2 List of operating costs of the dilute sulfuric acid resin regeneration and desorption process

[0043]

[0044] From the comparison data in Table 1 and Table 2 above, it can be seen that when treating 15m 3 water volume per day, the operating cost of the dilute nitric acid resin regeneration and desorption process is much lower than that of the dilute sulfuric acid resin regeneration and desorption process.

[0045] Such as Figure 1As shown in the figure, in step S1, the wastewater pretreated by the micro-nano air flotation device is pumped into the high-efficiency coagulation oil separator and the primary organic matter separator in sequence for treatment to remove the residual oil-containing pollutants, some dissolved macromolecular organic matter and suspended solids in the wastewater; then it is treated by a precision filter to remove the micron-sized suspended solids in the wastewater.

[0046] By adopting the above technical solution, the introduced high-efficiency coagulation oil separator, primary organic matter separator and precision filter, through structural optimization and multi-stage collaborative treatment, significantly improve the pretreatment effect of the explosive wastewater, ensure the stable operation of the subsequent resin adsorption system, reduce the operation cost and pollutant residue at the same time, and prevent problems such as resin caking and blockage as much as possible.

[0047] In the present invention, the high-efficiency coagulation oil separator is a key device specifically for oil-containing wastewater in industrial wastewater treatment, and realizes efficient oil-water separation through the synergistic action of physical-chemistry.

[0048] In the present invention, the primary organic matter separator is a primary treatment unit in the wastewater treatment system, mainly used for physically separating the suspended organic matter (such as grease, solid particles, fibers, etc.) in the wastewater, and providing pretreatment for subsequent biochemical treatment or advanced treatment. Its core goal is to reduce the subsequent treatment load and improve the overall treatment efficiency.

[0049] In the present invention, the precision filter is a key device for advanced wastewater treatment, mainly used for intercepting micron-sized particles, colloids, bacteria and some dissolved organic matter to ensure that the effluent meets high-purity standards (such as reuse or discharge requirements).

[0050] As Figure 1 shown, in step S2, the resin adsorption system is a 3-stage resin adsorption column, and the resin used on the resin adsorption column is ammonium ion-specific adsorption resin.

[0051] By adopting the above technical solution, the 3-stage resin adsorption column is in series with 3 columns (primary main adsorption + secondary supplementary adsorption + tertiary protection adsorption), each column is filled with ammonium ion-specific adsorption resin, equipped with a flow distribution valve and a pressure sensor; the wastewater flows through the first, second and third adsorption columns in sequence. When the first-stage resin is saturated, it is switched to the second column as the main adsorption column to achieve continuous operation; the three-stage series effectively improves the ammonia nitrogen adsorption rate, and the ammonia nitrogen concentration of the effluent meets the inlet water requirements of the biochemical system; through column sequence switching, the system does not need to stop for regeneration, and the treatment capacity is improved, adapting to the intermittent drainage characteristics of the explosive production line.

[0052] The removal effect of ammonium ion-specific adsorption resin on ammonia nitrogen in wastewater is mainly related to factors such as the actual concentration of ammonia nitrogen, the concentration of oil and grease pollutants in the wastewater, and the pH value of the wastewater. The dosage of the resin mainly affects the cycle of resin adsorption saturation. The more resin is added, the longer the continuous adsorption saturation cycle is.

[0053] Since dilute nitric acid has certain oxidizing properties while dilute sulfuric acid has no oxidizing properties, in terms of the oxidizing properties of acids, dilute nitric acid can oxidize oil pollutants in water, reducing the adsorption and exchange rate of oil pollutants on the resin. This is conducive to the adsorption, exchange, regeneration, and desorption of the resin, and relatively improves the adsorption and exchange capacity of the resin. Therefore, the resin used in the present invention must be resistant to the oxidation of dilute nitric acid.

[0054] The ammonium ion specific adsorption resin uses an interpenetrating polymerization process to form a "snake cage" type interpenetrating structure, greatly enhancing the strength of the resin and also improving its antioxidant capacity. Among them, the interpenetrating polymerization process is an advanced material synthesis technology that forms a stable composite structure by physically or chemically cross-linking two or more polymer networks. Its core feature is that the component networks are insoluble in each other but entangled, thereby synergistically improving the mechanical properties, thermal stability, and functional characteristics of the material. In the present invention, the ammonium ion specific adsorption resin is purchased from Xi'an Hairun New Materials Co., Ltd.

[0055] As Figure 1 shown, in step S3, the dilute nitric acid flushing regeneration and desorption is divided into two stages. The first stage uses a circulating regeneration liquid for desorption, and the second stage uses a newly prepared dilute nitric acid solution for desorption.

[0056] In the first stage, the dilute regeneration and desorption liquid generated from the previous dilute nitric acid regeneration and desorption is used to regenerate and desorb the resin bed. The concentrated regeneration and desorption liquid generated in this stage is stored in the ammonium nitrate solution storage tank after removing residual organic matter through a secondary organic matter separator, and the pH value is adjusted to 7.0 - 8.0 with sodium hydroxide solution and then reused in the drug dissolution process of the explosive production line.

[0057] In the second stage, a newly prepared 8% dilute nitric acid solution is used to continue the regeneration and desorption of the resin bed. The dilute regeneration and desorption liquid generated in this stage is stored in the dilute nitric acid flushing storage tank for use in the regeneration and desorption of the next adsorption-saturated resin column.

[0058] By adopting the above technical solution, the dilute nitric acid flushing regeneration and desorption is divided into two stages. This is mainly to save the usage amount of dilute nitric acid and at the same time save the amount of alkali used for adjusting the pH of recycled water. Generally, it saves the operating cost on the premise of ensuring the resin regeneration efficiency; at the same time, it can increase the concentration of the recycled ammonium nitrate solution. The dilute nitric acid used in the first stage of regeneration is the desorption liquid from the second stage of regeneration in the previous cycle (the main component is a small amount of ammonium nitrate, and the vast majority is a dilute nitric acid solution). The desorption liquid generated in this stage of regeneration is a concentrated regeneration and desorption liquid (the main components are ammonium nitrate and a small amount of dilute nitric acid, and the content of dilute nitric acid in this concentrated regeneration and desorption liquid accounts for 3% - 5%). The dilute nitric acid used in the second stage of regeneration is a newly prepared 8% dilute nitric acid solution, and the desorption liquid generated in the regeneration is used as the dilute nitric acid in the first stage of the next regeneration cycle.

[0059] In the first stage, the residual HNO3 and NH4 in the recycled liquid are + reused, reducing the consumption of newly prepared dilute nitric acid; after purification, the stripping solution is directly reused in the explosive dissolving process, effectively improving the recovery rate of ammonium nitrate.

[0060] The secondary organic matter separator removes trace organic matter (such as adsorbed oils or surfactants) released during resin regeneration, ensuring the purity of the ammonium nitrate solution and meeting the raw material standards for explosive production.

[0061] In the second stage, the newly prepared dilute nitric acid can provide sufficient H + , completely displacing the residual NH4 in the resin + , and regenerating and desorbing the ammonia nitrogen adsorbed in the resin as much as possible. The resin regeneration rate is effectively improved compared to the first stage, ensuring the stability of the adsorption capacity in the next cycle. All the dilute regeneration liquid is reused in the next cycle, and there is no waste acid discharge from the system, achieving zero discharge of the regeneration liquid.

[0062] The following is the principle and formula for regenerating and analyzing resin with dilute nitric acid:

[0063] The resin has hydrogen ion groups in its structure. The ammonium ion in water has a relatively large radius. When the wastewater containing ammonium ions passes through the resin, it exchanges with the hydrogen ions in the resin pores, and the ammonium ions are exchanged onto the resin, achieving the effect of removing ammonium ions from the wastewater.

[0064] When most of the H+ ion sites on the resin are exchanged, the resin loses its exchange ability and reaches the so-called "adsorption saturation". At this time, the resin needs to be regenerated and analyzed.

[0065] The regeneration principle is similar to the adsorption principle. Ammonium ions are exchanged from the resin with high-concentration hydrogen ions, and the resin resumes its exchange ability.

[0066] Adsorption exchange formula:

[0067]

[0068] Regeneration analysis formula:

[0069]

[0070] Among them, is the resin matrix.

[0071] The following Table 3 shows the comparison data of the resin regeneration and analysis rates using dilute nitric acid and dilute sulfuric acid:

[0072] Table 3 Comparison data of the resin regeneration and analysis rates using dilute nitric acid and dilute sulfuric acid

[0073]

[0074] As can be seen from the comparison data in Table 3 above, when treating the same raw water ammonia nitrogen concentration (mg / L), both the ammonia nitrogen adsorption removal rate and the resin regeneration rate using 8% dilute nitric acid are higher than those using 4% dilute sulfuric acid. At the same time, as the raw water ammonia nitrogen concentration (mg / L) increases, both the ammonia nitrogen adsorption removal rate and the resin regeneration rate using 8% dilute nitric acid and 4% dilute sulfuric acid decrease. However, the decrease rate using 8% dilute nitric acid is smaller than that using 4% dilute sulfuric acid.

[0075] (Note: In the traditional dilute sulfuric acid desorption process, the content of 4% dilute sulfuric acid is obtained according to the needs of resin desorption. Dilute sulfuric acid contains 2 H+, while dilute nitric acid contains 1 H+. Therefore, in the dilute nitric acid desorption process of the present invention, the content of dilute nitric acid is selected as 8%.)

[0076] Preferably, the desorption liquid generated in the first stage and the second stage is a mixed solution of dilute nitric acid with a content of 3% - 5% and ammonium nitrate.

[0077] The following Table 4 shows the comparison data table of the performance of the emulsion explosive produced from the mixed solution of 3% - 5% dilute nitric acid and ammonium nitrate obtained after treatment and the emulsion explosive produced from normal raw materials in various aspects.

[0078] Table 4

[0079]

[0080] As can be seen from the comparison data in Table 4 above, under the condition of ensuring the same specifications of the detected emulsion explosive, the emulsion explosive produced from the mixed solution of 3% - 5% dilute nitric acid and ammonium nitrate obtained after treatment and the emulsion explosive produced from normal raw materials are equivalent in various properties of the emulsion explosive such as density, gap test, brisance, and detonation number, belonging to the same grade.

[0081] As Figure 1 shown, the resin adsorption effluent generated is transported to the effluent collection tank, and after adjusting the pH value to 7.0 - 9.0 with sodium hydroxide solution, it is transported to the sewage treatment station for combined treatment to ensure up-to-standard discharge.

[0082] By adopting the above technical solutions, refined control of the regenerated wastewater is achieved, ensuring stable up-to-standard discharge at the end, and at the same time reducing the impact risk on the biochemical system. The effluent collection tank collects the resin adsorption effluent, buffers the instantaneous water volume and acidity changes, and avoids directly impacting the sewage treatment station.

[0083] As Figure 1As shown in the figure, the resin bed layer after acid regeneration analysis is pressured with compressed air to expel the residual dilute nitric acid in the resin bed layer, and then softened water is used to rinse the resin bed layer to wash away the bound water in the resin micropores. After the washing is completed, the resin column is reserved for the next adsorption cycle. Resin regeneration rinse wastewater is generated during this process.

[0084] By adopting the above technical solution, high-efficiency cleaning and rapid recovery of the adsorption performance after resin regeneration are achieved, while the operating cost is reduced and the long-term stable operation of the system is ensured.

[0085] Turbulence is formed by compressed air to quickly discharge the residual dilute nitric acid in the gaps and pores of the resin particles. The water content of the resin bed layer is effectively reduced, reducing the subsequent consumption of softened water; the discharged dilute nitric acid is returned to the storage tank for recycling, avoiding mixing into the softened water cleaning solution and causing a decrease in nitric acid concentration, and ensuring the regeneration efficiency of the next round.

[0086] Soft water dissolves and carries away the bound water and residual NH4 in the resin pores + , avoiding pore blockage and effectively improving the recovery rate of resin adsorption capacity; using soft water to avoid the combination of hard water ions such as Ca 2+ , Mg 2+ with the resin functional groups, reducing the risk of resin "poisoning" and extending the service life.

[0087] Such as Figure 1 As shown in the figure, the high-efficiency coagulating oil separator, the first-stage organic matter separator, and the second-stage organic matter separator are regularly subjected to air-water combined backwashing to discharge the suspended solids, oils, and organic matters intercepted therein; and the backwashing wastewater and the resin regeneration rinse wastewater are transported to the backwash water collection tank, and the pH value is adjusted to 7.0 - 9.0 with sodium hydroxide solution and then transported to the sewage treatment station for combined treatment to ensure up-to-standard discharge.

[0088] Preferably, soft water (demineralized water) is prepared from tap water by a soft water preparation system and transported to a soft water storage tank. The soft water in the soft water storage tank can be directly used for the water required by the sodium hydroxide solution preparation system; the soft water in the soft water storage tank is then transported to a four-stage rinsing tank for use in rinsing the resin bed layer and backwashing the filtration separation equipment.

[0089] By adopting the above technical solution, the cleaning efficiency of the pretreatment and regeneration units is significantly improved, while the water resource consumption and operating cost are reduced, ensuring the stability and sustainability of the entire wastewater treatment process.

[0090] For the high-efficiency coalescing oil separator, the gas-water mixed flow scours its inclined plates and filter media, stripping the adhered oils and suspended solids, and the porosity of the filter media recovers to a relatively high level after backwashing; for the organic matter separator, compressed air agitates its activated carbon bed layer, removing the organic matter blocking the pores, effectively increasing the recovery rate of the activated carbon adsorption capacity and extending the replacement cycle accordingly; the gas-water combined backwashing time is effectively shortened compared with the traditional single water washing time, and the energy consumption is also effectively reduced; the backwashing water volume is reduced, and the cost of backwashing per ton of water is reduced.

[0091] Soft water is used for resin sleeve washing and backwashing to avoid scaling of Ca 2+ and Mg 2+ in the resin pores or on the membrane surface, reducing the annual scaling rate of the equipment; the sodium hydroxide solution is prepared with soft water, with a purity of ≥99%, avoiding impurity interference with the recycling quality of the raw material (ammonium nitrate) for explosive production; the soft water storage tank serves for NaOH preparation, resin sleeve washing, and equipment backwashing at the same time, forming a "preparation-storage-distribution-recycling" closed loop and reducing the dependence on external water sources.

[0092] The specific usage process of the present invention is as follows:

[0093] When the present invention is in use, the explosive wastewater is collected through pipelines and enters the collection tank. After being accurately metered by the inlet water pump, it enters the micro-nano air flotation device. The micro-nano air flotation device removes pollutants such as suspended solids, oils, and surfactants in the explosive wastewater, and then is pumped to the wastewater temporary storage tank for temporary storage by a pump.

[0094] The explosive wastewater pretreated by the micro-nano air flotation device is accurately metered by the inlet water pump and then sequentially enters the high-efficiency coalescing oil separator and the first-stage organic matter separator to remove the remaining oil-containing pollutants, some dissolved macromolecular organic matter in the water, and suspended solids in the wastewater. Then it is filtered by a precision filter to further remove the micron-sized suspended solids in the water, as much as possible preventing problems such as resin caking and blockage.

[0095] The water outlet of the precision filter enters the intermediate water tank, and the wastewater is accurately metered by a water pump and pumped into the resin adsorption system (3-stage resin adsorption column). Under the selective adsorption of the ammonium ion-specific adsorption resin, the ammonia nitrogen in the explosive wastewater is adsorbed in the resin. The explosive wastewater with ammonia nitrogen adsorbed and removed enters the outlet water collection tank, and after adjusting the pH, it enters the sewage treatment station and is discharged up to standard after being combined with domestic sewage for treatment.

[0096] Whenever the first resin column is saturated (or nearly saturated) with adsorption, the first resin column is regenerated and analyzed by flushing the bed with 8% dilute nitric acid to desorb the ammonia nitrogen adsorbed in the resin, achieving the purpose of resin regeneration. The dilute nitric acid regeneration and analysis are divided into two stages: In the first stage, the dilute regeneration and analysis solution produced by the previous dilute nitric acid regeneration (this solution is mainly dilute nitric acid and a small amount of ammonium nitrate solution) is used. The concentrated regeneration and analysis solution produced in the first stage, after removing the residual organic matter through a secondary organic matter separator, is stored in the ammonium nitrate reuse storage tank. The main components of this solution are ammonium nitrate solution and a small amount of dilute nitric acid solution. After adjusting the pH value to the required value for production, it is reused in the drug dissolution process of the explosive production line. In the second stage, a newly prepared 8% dilute nitric acid solution is used to continue the regeneration and analysis of the resin bed to desorb as much ammonia nitrogen adsorbed in the resin as possible. The dilute regeneration and analysis solution produced in this stage (this solution is mainly dilute nitric acid and a small amount of ammonium nitrate solution) is stored in the dilute nitric acid flushing storage tank for use in the next regeneration of the resin column.

[0097] For the resin bed that has completed acid regeneration, compressed air is used to press out the residual dilute acid in the bed, and then soft water (demineralized water) is used to flush the resin bed to wash away the bound water (dilute acid) in the resin micropores. After completion, the resin column is reserved for the next adsorption cycle. The analysis solution desorbed by the dilute nitric acid is a mixed solution containing dilute nitric acid and ammonium nitrate.

[0098] In the process, the high-efficiency coagulating oil separator, the primary organic matter separator, and the secondary organic matter separator are regularly subjected to gas-water combined backwashing to discharge the suspended solids, oils, and organic matters intercepted in the separators, ensuring the stable and efficient operation of the system. The backwash water enters the backwash water storage tank. After adjusting the pH value, it enters the regulating tank of the comprehensive sewage treatment station through a pipeline and is treated together with domestic sewage for final discharge up to the standard.

[0099] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A green treatment process for explosive wastewater, characterized in that, The process includes the following steps: Step S1, pretreatment stage: Pump the collected explosive wastewater into the micro-nano air flotation device to remove suspended solids, oils and surfactants in the explosive wastewater; Step S2, resin adsorption stage: Pump the pretreated explosive wastewater into the resin adsorption system, and selectively adsorb and remove ammonia nitrogen pollutants in the wastewater through the resin. In this stage, resin adsorption effluent with ammonia nitrogen removed by adsorption is produced; Step S3, regeneration and desorption stage: Use dilute nitric acid to wash and regenerate and desorb the saturated resin to desorb and separate the ammonia nitrogen adsorbed in the resin. In this stage, concentrated regeneration and desorption liquid is produced by desorption; Step S4, product reuse stage: Adjust the pH value of the concentrated regeneration and desorption liquid produced by desorption after impurity removal treatment to obtain ammonium nitrate solution for reuse in the explosive production process; Step S5, waste liquid treatment stage: Adjust the pH value of the resin adsorption effluent and then transport it to the sewage treatment station for combined treatment to ensure up-to-standard discharge.

2. The green treatment process for explosive wastewater according to claim 1, wherein: In the said Step S1, the wastewater pretreated by the micro-nano air flotation device is pumped into a high-efficiency coagulating oil remover and a primary organic matter separator in sequence for treatment to remove residual oil-containing pollutants, some dissolved macromolecular organic matters and suspended solids in the wastewater; then it is treated by a precision filter to remove micron-sized suspended solids in the wastewater.

3. A green treatment process for explosive wastewater according to claim 1, characterized in that: In the said Step S2, the resin adsorption system is a 3-stage resin adsorption column, and the resin used on the resin adsorption column is ammonium ion specific adsorption resin.

4. A green treatment process for explosive wastewater according to claim 3, characterized in that: In the said Step S3, the dilute nitric acid washing, regeneration and desorption are divided into two stages. In the first stage, the resin bed is regenerated and desorbed using the recycled regeneration liquid, and in the second stage, the newly prepared dilute nitric acid solution is used for regeneration and desorption.

5. A green treatment process for explosive wastewater according to claim 4, characterized in that: In the first stage, the dilute regeneration and desorption liquid produced by the previous dilute nitric acid regeneration and desorption is used to regenerate and desorb the resin bed. The concentrated regeneration and desorption liquid produced by regeneration and desorption in this stage is stored in the ammonium nitrate solution storage tank after removing residual organic matters by the secondary organic matter separator, and the pH value is adjusted to 7.0 - 8.0 using sodium hydroxide solution and then reused in the medicine dissolving process of the explosive production line.

6. The green treatment process for explosive wastewater according to claim 5, characterized in that: In the second stage, the newly prepared 8% dilute nitric acid solution is used to continue regenerating and desorbing the resin bed. The dilute regeneration and desorption liquid produced by regeneration and desorption in this stage is stored in the dilute nitric acid washing storage tank for use in the regeneration and desorption of the next adsorption-saturated resin column.

7. A green treatment process for explosive wastewater according to claim 6, characterized in that: The desorption liquid produced in the first stage is a mixed liquid of dilute nitric acid with a content of 3% - 5% and ammonium nitrate.

8. A green treatment process for explosive wastewater according to claim 1, characterized in that: The resin adsorption effluent produced in the said Step S2 is transported to the effluent collection tank, and the pH value is adjusted to 7.0 - 9.0 using sodium hydroxide solution and then transported to the sewage treatment station for combined treatment to ensure up-to-standard discharge.

9. A green treatment process for explosive wastewater according to claim 5, characterized in that: Use compressed air to press the residual dilute nitric acid in the resin bed of the resin bed after acid regeneration and desorption is completed, and then use soft water to wash the resin bed to wash away the bound water in the resin micropores. After the washing is completed, the resin column is reserved for the next adsorption cycle. Resin regeneration washing wastewater is produced during this process.

10. A green treatment process for explosive wastewater according to claim 9, characterized in that: The high-efficiency coagulation oil separator, the first-stage organic matter separator, and the second-stage organic matter separator are regularly subjected to air-water combined backwashing to discharge the suspended solids, oils, and organic matters intercepted therein; and the backwashing wastewater and the resin regeneration flushing wastewater are transported to the backwashing water collection tank, and after adjusting the pH value to 7.0-9.0 with sodium hydroxide solution, they are transported to the sewage treatment station for combined treatment to ensure up-to-standard discharge.

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