Water quality detection waste liquid treatment method and system

Abstract

The embodiment of the invention provides a water quality detection waste liquid treatment method. The method comprises the following steps: at least dividing waste liquid generated by a monitoring station into chromium-containing waste liquid, organic reagent-containing waste liquid and acid waste liquid, and respectively collecting the chromium-containing waste liquid, the organic reagent-containing waste liquid and the acid waste liquid; treating the chromium-containing waste liquid to generate an iron-containing solution rich in iron ions, adjusting the solution to a stable pH range by using the collected acidic waste liquid, and storing the solution; the stored iron-containing solution is used as a catalyst to treat the organic reagent-containing waste liquid, and an internal circulation form of chromium-containing waste liquid iron production-waste acid iron stabilization-iron catalytic oxidation of organic matters is constructed, so that efficient removal of toxic pollutants in the waste liquid and cyclic utilization of in-station resources are realized; the consumption of exogenous agents and the transportation volume of hazardous wastes are greatly reduced, and the operation cost is reduced. The invention also provides a treatment system applying the method.

Description

Technical Field

[0001] This invention relates to a method for treating wastewater from water quality testing and a system for applying this method. Background Technology

[0002] Automatic surface water quality monitoring is widely used in monitoring work to obtain real-time and continuous information on surface water quality dynamics, providing scientific data support for water resource protection, pollution prevention and control, and management decisions. The process of evaluating water quality involves a very broad monitoring scope, including unpolluted and polluted natural water as well as various industrial wastewater. The main monitoring items can be divided into two categories: one is comprehensive indicators reflecting water quality, such as temperature, color, turbidity, pH, conductivity, suspended solids, dissolved oxygen, chemical oxygen demand (COD), and biochemical oxygen demand (BOD); the other is toxic substances, such as phenols, cyanides, arsenic, lead, chromium, cadmium, mercury, and organochlorine pesticides.

[0003] During water quality testing and monitoring, automatic monitoring stations analyze water quality according to national standard methods, such as the potassium dichromate method for chemical oxygen demand determination (HJ 828-2017) and the Nessler's reagent spectrophotometric method for ammonia nitrogen determination (HJ 535-2009). This process generates complex and highly toxic chemical reagent waste liquids, mainly including: chromium-containing and strongly oxidizing waste liquids (from potassium dichromate and potassium persulfate), organic reagent-containing waste liquids (from Nessler's reagent, potassium sodium tartrate, diphenylcarbazide, etc.), heavy metal-containing waste liquids (from mercuric sulfate, silver sulfate, etc.), and large amounts of acidic or alkaline cleaning waste liquids. Currently, the main treatment methods for these waste liquids are as follows: 1. After being sorted and collected, the waste liquid is regularly transported to a professional disposal unit as hazardous waste. However, water quality monitoring stations are usually located in remote and scattered locations, such as the field or groundwater monitoring stations described in CN218470695U and CN121141260A. This model has significant drawbacks, including high transportation costs, long cycles, high risk of leakage during transit, and inability to meet the real-time environmental protection requirements of the monitoring process.

[0004] 2. Some existing technologies also attempt on-site treatment solutions, such as the system for treating laboratory wastewater from environmental monitoring stations disclosed in CN215440089U, which employs a combination of processes including catalytic micro-electrolysis, advanced oxidation, and biosorption. However, such solutions typically involve mixing various waste liquids with vastly different properties for treatment, leading to problems such as interference between pollutants, strong oxidants damaging microorganisms, acid-base neutralization consuming reagents, low treatment efficiency, and lack of specificity. Furthermore, they often require the addition of large amounts of exogenous chemical agents, such as the various coagulants and flocculants mentioned in CN222374389U, which may introduce new pollution and increase operating costs.

[0005] Therefore, there is currently a lack of solutions for treating small, intermittent, and complex waste liquids from water quality testing, especially automatic water quality monitoring stations. At the same time, it is also necessary to consider their remote locations and unattended operation, and to extend their operating time as much as possible. Summary of the Invention

[0006] Therefore, the present invention provides a method for treating wastewater from water quality testing to solve the above-mentioned technical problems.

[0007] A method for treating wastewater from water quality testing includes the following steps: S10: Waste liquid generated during water quality testing shall be collected separately from at least three categories: chromium-containing waste liquid, organic reagent-containing waste liquid, and acidic waste liquid; S20: Treat the chromium-containing waste liquid to produce an iron-containing solution rich in iron ions, and then use the collected acidic waste liquid to adjust the iron-containing solution to a predetermined pH range before storing it; S30: Use the stored iron-containing solution as a catalyst to treat the waste liquid containing organic reagents.

[0008] Step S20 is performed as follows: S201: The chromium-containing waste liquid is pumped into the electrochemical reduction reactor and an electrochemical reaction is carried out; S202: Transfer the solution treated in step 201 to the primary mixing tank and adjust the pH of the primary mixing tank to 4.0-5.5; S203: Transfer the solution to the precipitation reaction tank, add alkaline solution and selective precipitation aid, and adjust the pH to 8.0-9.0 to form Cr(OH)3 precipitate; S204: Solid-liquid separation forms an iron-rich solution and chromium-containing sludge. S205: Transfer the iron-containing solution to a storage tank and inject acidic waste liquid into the storage tank to adjust the pH to a predetermined range.

[0009] Step S30 is performed as follows: S301: Pump the organic waste liquid to be treated into the electric Fenton reactor; S302: Based on the initial chemical oxygen demand (COD) concentration of the organic waste liquid to be treated, according to the preset Fe... 2+ COD molar ratio, injecting iron-containing solution into the electro-Fenton reactor; S303: Adjust the pH to 2.5-3.5; S304: Performs electro-Fenton advanced oxidation reactions; S305: Solid-liquid separation forms effluent and iron-containing sludge.

[0010] In step S10, alkaline waste liquid is collected, and the alkaline solution added in step S203 is alkaline waste liquid.

[0011] The predetermined range mentioned in step 205 is PH2.0-3.5.

[0012] In step S303, when adjusting the pH, the acidic waste liquid collected in step S10 is added to adjust the pH.

[0013] In step 305, the method further includes transferring the solution from the electro-Fenton advanced oxidation reaction to a neutralization flocculation tank and adding alkali solution and flocculant, wherein the alkali solution added is an alkaline waste liquid.

[0014] In step 305, an alkaline solution is added to adjust the pH to 7-8, and the flocculant is polyacrylamide.

[0015] In step 203, the selective precipitation aid may be sodium carbonate, and after step 203, a flocculant may be added, which may be polyacrylamide.

[0016] This invention also provides a wastewater treatment system for an automatic water quality monitoring station, comprising: The sorting and collection unit includes at least three independent waste liquid collection containers, which are used to collect chromium-containing waste liquid, organic reagent-containing waste liquid, and acidic waste liquid, respectively. A chromium-containing waste liquid treatment unit, connected to the chromium-containing waste liquid collection container, includes an electrochemical reduction reactor, a precipitation device and a first solid-liquid separation module, for treating the chromium-containing waste liquid and producing an iron-containing solution rich in iron ions. The chromium-containing waste liquid treatment unit also includes a storage tank for storing the iron-containing solution. An organic reagent waste liquid treatment unit, connected to the organic reagent waste liquid collection container, is configured to treat the organic reagent waste liquid using a stored iron-containing solution as a catalyst.

[0017] Beneficial Effects: This invention provides a method for treating wastewater from water quality testing, comprising: collecting wastewater generated by a monitoring station into at least three categories: chromium-containing wastewater, organic reagent-containing wastewater, and acidic wastewater; treating the chromium-containing wastewater to produce an iron-rich solution, and using the collected acidic wastewater to adjust the solution to a stable pH range before storage; and then using the stored iron-rich solution as a catalyst to treat the organic reagent-containing wastewater. By constructing an internal circulation model of chromium-containing wastewater iron production-waste acid iron stabilization-iron catalytic oxidation of organic matter, the method achieves efficient removal of toxic pollutants from the wastewater and recycling of resources within the station, significantly reducing the consumption of external reagents and the amount of hazardous waste transported, and lowering operating costs. This invention also provides a treatment system applying the above method. Attached Figure Description

[0018] Figure 1Schematic diagram of the components of a water quality testing wastewater treatment system; Figure 2 A schematic diagram of the modules and operation flow of a water quality testing wastewater treatment system; Explanation of component symbols in the diagram: Automatic water quality monitoring station 10; treatment system 100; collection unit 20; chromium-containing waste liquid collection tank 21; acidic waste liquid collection tank 22; organic reagent-containing waste liquid collection tank 23; alkaline waste liquid collection tank 24; heavy metal waste liquid collection tank 25; chromium-containing waste liquid treatment unit 30; electrochemical reduction reactor 31; primary mixing tank 32; precipitation reaction tank 33; first solid-liquid separation module 34; storage tank 35; organic reagent-containing waste liquid treatment unit 40; Electro-Fenton reactor 41; neutralization flocculation tank 42; second solid-liquid separation module 43; advanced treatment unit 50; moving bed biofilm reactor 51; activated carbon adsorption tank 52; security filter 53; sludge treatment unit 60; control system 70. Detailed Implementation

[0019] This invention provides a method for treating wastewater from water quality testing, specifically a method for treating wastewater generated by an automatic water quality monitoring station 10, comprising the following steps: S10: Waste liquid generated during water quality testing shall be collected separately from at least three categories: chromium-containing waste liquid, organic reagent-containing waste liquid, and acidic waste liquid.

[0020] Understandably, the water quality testing mentioned above specifically refers to water quality testing performed by the automatic water quality monitoring station 10. The water quality monitoring station 10 includes an analysis and testing unit comprising several analysis modules, wherein the analysis modules include: Chemical oxygen demand (COD) analysis module: It is configured to use the potassium dichromate method (HJ 828-2017) for detection and analysis. The detection and analysis uses reagents such as potassium dichromate, mercuric sulfate, silver sulfate, and concentrated sulfuric acid, and generates a strong acidic and strong oxidizing waste liquid containing chromium, mercury, and silver.

[0021] Ammonia nitrogen analysis module: It is configured to use Nessler's reagent spectrophotometry (HJ 535-2009) for detection and analysis. Nessler's reagents such as mercuric iodide, potassium iodide, sodium hydroxide, and potassium sodium tartrate are used in the detection and analysis, and alkaline waste liquid containing mercury, ammonium salts and organic reagents is generated.

[0022] Total phosphorus / total nitrogen analysis module: It is configured to use ammonium molybdate spectrophotometry (HJ 670-2013) or potassium persulfate digestion-ultraviolet spectrophotometry for detection and analysis. Potassium persulfate, ammonium molybdate, ascorbic acid, etc. are used in the detection and analysis, and waste liquid containing phosphorus and nitrogen nutrients and organic / inorganic reagents is generated.

[0023] The standard five parameters and other modules generate acid, alkali or electrolyte cleaning waste liquid during electrode maintenance and cleaning.

[0024] Furthermore, the analytical detection unit can also be configured with a heavy metal analysis module: configured to perform detection and analysis using atomic absorption, inductively coupled plasma, or spectrophotometry. Specifically, for example, hexavalent chromium is determined using diphenylcarbazide, which generates waste liquid containing chromium and organic complexing agents; copper, lead, cadmium, etc. are determined using chelation extraction or direct determination, which generates waste liquid containing specific heavy metal ions, acids, and masking agents such as EDTA.

[0025] In addition, each analysis module has an automatic cleaning process before and after each measurement. The automatic cleaning process uses dilute nitric acid, dilute sulfuric acid or pure water to clean the flow path and generates acidic or neutral cleaning waste liquid.

[0026] Based on the above-mentioned waste liquid, in step S10, the waste liquid is divided into at least three categories and collected through corresponding collection systems. The waste liquid specifically includes: Chromium-containing wastewater: The chromium-containing wastewater originates from the COD analysis module. Its main components include hexavalent chromium (Cr(VI)) and mercury ions (Hg). 2+ ), silver ions (Ag) + The waste liquid contains sulfate, high-concentration acid, and has strong oxidizing and acidic properties, as well as various heavy metals.

[0027] Organic reagent waste liquid: The organic reagent waste liquid comes from the ammonia nitrogen analysis module and the total phosphorus / total nitrogen analysis module. The main components of the organic reagent waste liquid include Nessler's reagent (containing mercury), potassium sodium tartrate, potassium persulfate, ammonium molybdate, ascorbic acid, diphenylcarbazide and other organic matter, as well as ammonia nitrogen and phosphate. The waste liquid contains organic pollutants and complexed heavy metals and may be alkaline or neutral.

[0028] Acidic waste liquid: The acidic waste liquid comes from the acidic cleaning process of each module and the acidic medium of some reagents. The main components of the acidic waste liquid include dilute nitric acid, dilute sulfuric acid and hydrochloric acid. In some embodiments, it may also include trace pollutants. The waste liquid can be used to adjust the pH.

[0029] Furthermore, the waste liquid is further classified into heavy metal waste liquid and alkaline waste liquid.

[0030] Among them, heavy metal waste liquid: the heavy metal waste liquid comes from the heavy metal analysis module. The main components of the heavy metal waste liquid include heavy metal ions, acidic media, and masking agents such as EDTA and cyanide. The heavy metal waste liquid contains a variety of heavy metals and may contain complexing agents.

[0031] Among them, alkaline waste liquid: The alkaline waste liquid comes from the alkaline cleaning process of each module and the alkaline medium of some reagents. The main components of the alkaline waste liquid include dilute sodium hydroxide, potassium hydroxide, etc. It can be understood that the alkaline waste liquid is a low concentration of alkali and can be used to neutralize or adjust the pH.

[0032] S20: Treat the chromium-containing waste liquid to produce an iron-containing solution rich in iron ions, and then use the collected acidic waste liquid to adjust the iron-containing solution to a predetermined pH range before storing it.

[0033] In this embodiment, an electrochemical reduction reaction is used to treat chromium-containing waste liquid to produce an iron-rich solution, and the pH is adjusted using the acidic waste liquid collected in step S10. Specifically, the steps include the following: S201: The chromium-containing waste liquid is pumped into the electrochemical reduction reactor 31 and an electrochemical reaction is carried out.

[0034] Understandably, the electrochemical reduction reactor 31 includes an electrode pair consisting of a soluble iron anode and an inert cathode, so as to generate an electrochemical reaction after applying a direct current to the anode and cathode, specifically including the following reactions: Anodic reaction: Fe → Fe 2+ + 2e - ; Cathode reaction: Cr2O7 2- + 14H + + 6e - → 2Cr 3+ + 7H2O; Homogeneous reaction in solution: Cr2O7 2- + 6Fe 2+ + 14H + → 2Cr 3+ + 6Fe 3+ + 7H2O; In this process, the anodic reaction involves the dissolution of iron, which provides the reducing agent Fe to the system. 2+ In the cathodic reaction, Cr(VI) is directly reduced to Cr(III), and in the homogeneous solution reaction, Fe... 2+ Indirect reduction of Cr(VI) to Cr(III) involves reducing highly toxic and migratory Cr(VI) to less toxic and easily precipitated Cr(III), while simultaneously introducing a large amount of Fe into the system. 2+ / Fe 3+ ion.

[0035] S202: Transfer the solution treated in step 201 to the primary mixing tank 32 and adjust the pH of the primary mixing tank 32 to 4.0-5.5.

[0036] Understandably, under pH conditions of 4.0-5.5, some Fe... 3+ Preliminary hydrolysis or formation of hydroxyl complexes occurs, Cr 3+ It remains in a dissolved state.

[0037] S203: Transfer the solution to the precipitation reaction tank 33, slowly add alkaline solution and selective precipitation aid, and adjust the pH to 8.0-9.0 to form Cr(OH)3 precipitate.

[0038] The alkaline solution can be a NaOH solution. Furthermore, when the waste liquid includes alkaline waste liquid, the alkaline solution can be the alkaline waste liquid collected in step S10.

[0039] The selective precipitation aid can be sodium carbonate, which is used to provide alkalinity and CO3. 2- To form carbonate coprecipitates.

[0040] Furthermore, a flocculant can be added after step 203 to promote the precipitation of Cr(OH)3.

[0041] The flocculant mentioned above can be polyacrylamide (PAM).

[0042] By controlling the pH and adding selective precipitation aids, Cr 3+ Cr(OH)3 precipitate is formed. By controlling the above conditions, more than 70% of the total iron ions can be retained in the iron-containing solution, while more than 95% of the chromium forms chromium-containing sludge that can be easily removed.

[0043] S204: Solid-liquid separation forms an iron-rich solution and chromium-containing sludge.

[0044] In this embodiment, solid-liquid separation can be performed by a first solid-liquid separation module 34, which can be a tubular centrifuge or a ceramic membrane filtration system to quickly separate chromium-containing sludge from an iron-rich solution.

[0045] The iron-rich solution refers to the supernatant obtained in step S204, in which iron ions are the main soluble metal component. Its total iron concentration is typically above 150 mg / L, preferably 200-800 mg / L, and more preferably 300-600 mg / L. The total iron concentration can be determined by the method of "Determination of Iron in Water by 1,000-Phenanthroline Spectrophotometric Method" (HJ / T345-2007).

[0046] S205: Transfer the iron-containing solution to storage tank 35 and inject acidic waste liquid into storage tank 35 to adjust the pH to a predetermined range.

[0047] In this embodiment, the predetermined range is pH 2.0-3.5, within which Fe can be effectively suppressed. 2+ oxidation and Fe 3+ Hydrolysis precipitation is used to ensure that iron ions exist stably in a dissolved state.

[0048] Furthermore, after step 205, the method further includes monitoring the pH within the storage tank 35 and ensuring that the pH within the storage tank 35 is within a predetermined range.

[0049] Specifically, the storage tank 35 is equipped with an automatic pH monitoring and acid replenishment system to ensure pH stability during storage.

[0050] Understandably, through step S20, on the one hand, highly toxic Cr(VI) is specifically converted into low-toxic Cr(III) and separated by electrochemical reduction; on the other hand, an iron catalyst required for treating organic reagent waste liquid is generated in this process; and on the third hand, another waste liquid generated during the water quality monitoring station detection process, acidic waste liquid, is used to adjust and maintain the pH environment in which the iron catalyst can be stably stored. This not only saves the purchase of acid agents, but also ensures that the iron ion catalyst can be stored stably in a highly active dissolved state for a long time.

[0051] S30: Use the stored iron-containing solution as a catalyst to treat the waste liquid containing organic reagents.

[0052] In this embodiment, the waste liquid containing organic reagents is treated by electro-Fenton advanced oxidation reaction, specifically including the following steps: S301: Pump the organic waste liquid to be treated into the electro-Fenton reactor 41.

[0053] S302: Based on the initial chemical oxygen demand (COD) concentration of the waste liquid, according to the preset Fe... 2+ COD molar ratio, an iron-containing solution is injected into the reactor.

[0054] The initial chemical oxygen demand (COD) concentration can be estimated by an online ultraviolet absorption spectrometer or by the COD data detected by the automatic water quality monitoring station 10.

[0055] Among them, the preset Fe 2+ The COD molar ratio can be 0.05-0.15. For typical organic reagent waste liquids generated by water quality monitoring stations, such as those containing Nessler's reagent and color reagents, this molar ratio range can ensure sufficient generation of hydroxyl radicals on the one hand, and avoid subsequent sludge volume surge and color problems caused by excessive iron ions on the other hand.

[0056] Understandably, the iron-containing solution is quantitatively extracted from the storage tank 35 storing the iron-containing solution according to a preset ratio and injected into the reactor as a catalyst.

[0057] S303: Adjust the pH to 2.5-3.5.

[0058] Understandably, the Fenton reaction generates hydroxyl radicals (·OH) most efficiently in the pH range of 2.5-3.5. However, the pH of the organic waste liquid to be treated is not always in the pH range of 2.5-3.5. Therefore, it is necessary to adjust the pH of the solution in the reactor. Specifically, the pH can be adjusted by injecting acidic waste liquid into the reactor, thereby further utilizing the waste liquid generated by the automatic water quality monitoring station 10 and realizing waste treatment with waste.

[0059] S304: Performs electro-Fenton advanced oxidation reaction.

[0060] Specifically, under the influence of a DC electric field, the following core reactions occur within the reactor: Cathode reaction: O2 + 2H + + 2e - → H2O2, H2O2 is generated in situ; Homogeneous Fenton reaction: Fe 2+ + H2O2 → Fe 3+ + ·OH + OH - This produces ·OH, a strong oxidizing agent. Cathode regeneration reaction: Fe 3+ + e - → Fe 2+ Cathodic reduction of Fe 3+ This enables the electrochemical regeneration of iron catalysts; Understandably, the generated highly oxidizing ·OH free radicals non-selectively attack and mineralize organic pollutants, decomposing them into CO2, H2O, and small molecule inorganic acids. At the same time, the advanced oxidation process can effectively destroy heavy metal complexes, such as Hg-EDTA, releasing heavy metal ions, which is beneficial for subsequent removal.

[0061] S305: Solid-liquid separation forms effluent and iron-containing sludge.

[0062] Specifically, it includes the following steps: S3051: Transfer the reaction solution to neutralization and flocculation tank 42, and add alkali solution and flocculant.

[0063] The alkaline solution can be the alkaline waste liquid from step S10.

[0064] The flocculant mentioned above can be polyacrylamide (PAM).

[0065] When adding alkali solution, adjust the pH of the solution to pH 7-8. After adding flocculant, the iron sludge and heavy metal hydroxides will form larger flocs.

[0066] Furthermore, in step S3051, sodium sulfide or a DTC-type heavy metal trapping agent is added to further reduce the mercury content.

[0067] S3052: Solid-liquid separation.

[0068] In this step, solid-liquid separation can be performed using the second solid-liquid separation module 43. This second solid-liquid separation module 43 can be a sedimentation tank or a membrane filter. It is understood that the iron-containing sludge formed after solid-liquid separation contains a large amount of Fe. 3+ And heavy metals, which are disposed of as hazardous waste.

[0069] Understandably, through step S30, the electro-Fenton advanced oxidation reaction efficiently degrades pollutants generated during the water quality monitoring station's detection process: organic reagents. On the other hand, as a key hub for the system's resource recycling, it consumes the iron generated in S20 and the waste acid collected in S10, forming a waste-to-waste system, reducing the need to introduce external reagents, thereby extending the operating time and reliability of the water quality monitoring station.

[0070] Furthermore, after step S30, a step of further treating the effluent after step S30 is also included.

[0071] Specifically, the depth processing includes the following steps: S401: Biological treatment.

[0072] Specifically, ammonia nitrogen, nitrate, nitrite and residual biodegradable organic matter (BOD) in the S30 effluent are further removed by microorganisms. In one specific embodiment, a moving bed biofilm reactor 51 (MBBR) can be used for biological treatment. The moving bed biofilm reactor 51 is filled with suspended packing material of polyethylene or polyurethane, accounting for 30%-50% of the tank volume, and nitrifying bacteria, including Nitrosomonas and Nitrifying Bacillus.

[0073] In one specific embodiment, the hydraulic retention time (HRT) of the moving bed biofilm reactor 51 is 4-8 hours, and it is equipped with a blower or air pump for intermittent aeration. The dissolved oxygen (DO) is controlled at 2-4 mg / L, and the water temperature of the moving bed biofilm reactor 51 is 10-35℃, which is suitable for field environments.

[0074] Furthermore, after step S30, an H2O2 quenching step is included to reduce the inhibitory effect of the effluent on microorganisms. The H2O2 quenching can be achieved by leaving the effluent in place or by adding a reducing agent.

[0075] S402: Activated carbon adsorption.

[0076] The effluent from the biological treatment in step S401 flows into the activated carbon adsorption tank 52 filled with granular activated carbon for activated carbon adsorption. Understandably, the activated carbon adsorption removes residual color, trace organic matter, and odor.

[0077] S403: Security Filter.

[0078] Security filtration is achieved through 5-10 micron bag filters or filter cartridges, which trap tiny particles such as biofilm detachment and activated carbon powder.

[0079] Furthermore, after step 403, ions, organic matter, colloids, bacteria, and viruses can be further removed by reverse osmosis (RO).

[0080] Furthermore, the sludge produced in steps S20 and S30 can be reduced in volume through thickening and dewatering processes to facilitate transportation.

[0081] Furthermore, in step S20 or S30, if pH needs to be adjusted and the acidic or alkaline waste liquid is insufficient or cannot be adjusted to the predetermined pH range, dilute acid or dilute alkali can be taken from the analysis module in the water quality monitoring station.

[0082] Furthermore, when a heavy metal analysis module is included, a step of separately treating the heavy metal wastewater generated by the heavy metal analysis module may also be included. This separate treatment includes using adsorption materials with high selectivity and affinity for heavy metal ions, such as sulfide-functionalized (-SH) resins or mesoporous materials for adsorption treatment. It is understood that the adsorption material can capture Hg in the solution. 2+ Cu 2+ Pb 2+ Heavy metal ions.

[0083] This invention also provides a processing system 100 applying the above-described processing method, which please refer to accordingly. Figure 1 and Figure 2 The processing system 100 includes a collection unit 20, a chromium-containing waste liquid treatment unit 30, and an organic reagent-containing waste liquid treatment unit 40.

[0084] Furthermore, it may also include a deep treatment unit 50 and a sludge treatment unit 60.

[0085] The collection unit is configured to collect waste liquid generated by the automatic water quality monitoring station 10 in a classified manner, including at least a chromium-containing waste liquid collection tank 21, an acidic waste liquid collection tank 22, and an organic reagent-containing waste liquid collection tank 23. Further, it may also include an alkaline waste liquid collection tank 24 and a heavy metal waste liquid collection tank 25.

[0086] The chromium-containing waste liquid treatment unit 30 includes an electrochemical reduction reactor 31, a primary mixing tank 32, a precipitation reaction tank 33, a first solid-liquid separation module 34, and a storage tank 35.

[0087] The organic reagent waste liquid treatment unit 40 includes an electro-Fenton reactor 41, a neutralization flocculation tank 42, and a second solid-liquid separation module 43.

[0088] The deep treatment unit 50 includes a moving bed biofilm reactor 51 and an activated carbon adsorption and security filter 53.

[0089] The sludge treatment unit 60 includes a thickening device and a dewatering device.

[0090] Understandably, the system may also include a control system 70 to control the collection unit 20, the chromium-containing waste liquid treatment unit 30, the organic reagent-containing waste liquid treatment unit 40, the deep treatment unit 50, and the sludge treatment unit 60 to form an automated treatment process.

[0091] Example 1: Overview of the water quality monitoring station: Equipped with five-parameter analysis modules for COD, ammonia nitrogen, total phosphorus, and total nitrogen, it generates approximately 15-25 liters of various waste liquids per day.

[0092] Waste liquid collection (S10): Chromium-containing wastewater: originates from the COD module, averaging approximately 2-4 L per day. It is strongly acidic, with a Cr(VI) concentration of 800-1200 mg / L and contains Hg. 2+ Ag + And a small amount of organic impurities.

[0093] Waste liquid containing organic reagents: originating from the ammonia nitrogen, total phosphorus and total nitrogen modules, approximately 4-7 L per day, weakly alkaline, with a COD of approximately 2000-3500 mg / L, containing Nessler's reagent (mercury), ascorbic acid, etc.

[0094] Acidic waste liquid: comes from the pickling process of each module, about 3-6 L per day, which is 1-5% dilute nitric acid / sulfuric acid.

[0095] Alkaline waste liquid: comes from the alkaline washing process, about 2-5 L per day, which is a 1-3% NaOH solution.

[0096] Chromium-containing wastewater treatment (S20): 3L of chromium-containing waste liquid (Cr(VI) concentration approximately 1100 mg / L in this case) was pumped into electrochemical reduction reactor 31 (iron anode / graphite cathode, current density 20 mA / cm²). 2The reaction was carried out for 100 minutes. After adjusting the pH of the effluent to 5.0, 0.5L of alkaline wastewater and 5g of sodium carbonate were added, and the pH was adjusted to 8.5. Then, 1mL of 0.1% PAM was added. The mixture was separated by a tubular centrifuge to obtain approximately 0.4L of chromium-containing sludge (85% water content) and approximately 2.6L of iron-containing solution (total iron concentration approximately 420 mg / L). This solution was stored in an iron ion storage tank, and 0.2L of acidic wastewater was added to stabilize the pH at 2.8.

[0097] Organic waste liquid treatment (S30): Take 5L of organic waste liquid (COD=2800 mg / L) and pump it into the electro-Fenton reactor 41. According to Fe... 2+ With a COD of 0.08, approximately 1.2 L of iron-containing solution was drawn from the storage tank and injected, followed by 0.3 L of acidic waste liquid. The pH was adjusted to 3.0, and the reaction was allowed to proceed for 120 minutes. After the reaction, 0.8 L of alkaline waste liquid was added to the effluent to adjust the pH to 7.5. Then, 0.5 g of DTC heavy metal precipitant and PAM were added for flocculation, followed by precipitation and separation. The supernatant was quenched to remove residual H₂O₂.

[0098] Deep processing (S40): The effluent enters the MBBR tank (HRT=6 hours) for biological treatment, followed by activated carbon adsorption and security filtration. The final effluent is clear, with COD <30 mg / L, ammonia nitrogen <1 mg / L, total chromium not detected (<0.05 mg / L), and mercury <0.001 mg / L. The water quality is superior to the Class A standard of the "Water Quality Standard for Wastewater Discharge into Urban Sewerage Systems" (GB / T 31962-2015) and can be directly discharged into the pipe network or reused for flushing within the station.

[0099] In addition, the sludge from steps S20 and S30 is dewatered to form hazardous waste sludge cakes (moisture content <60%), which are then transported off-site.

[0100] During the trial operation of this embodiment, no iron salts, acids, or alkalis were purchased externally; the system could operate solely by relying on the internal circulation of waste liquid within the station.

[0101] Comparative Example 1: Traditional mixed off-site disposal method: All waste liquids in the station are stored together in large waste liquid tanks without being classified, and are handed over to a third party for off-site disposal as "HW49 Other Waste" every month.

[0102] The wastewater treatment scheme of the water quality monitoring station in this embodiment is compared with the treatment method of Comparative Example 1 as follows: ; As can be seen, compared with existing treatment methods, the treatment method provided by this invention has several advantages. First, it can transform the high-risk liquid mixtures that need to be transported for disposal into stable solid sludge cakes, thereby completely eliminating safety hazards such as leakage and reaction during on-site storage and long-distance transportation, significantly reducing environmental risks. Second, by recycling chromium-containing waste liquid to produce iron and waste acid / alkali in a material recycling chain, the cost of purchasing core reagents such as iron salts, acids, and alkalis is avoided, thus reducing operating costs. Third, because the volume of transported solid waste is extremely small (approximately 2 kg / month), the disposal cost is extremely low, significantly reducing the treatment cost of hazardous waste compared to the traditional method of transporting large amounts of liquid hazardous waste (approximately 200 L / month). Fourth, this invention can achieve fully automated, integrated operation and immediate treatment, eliminating the need for managing large hazardous waste storage tanks on-site, requiring only monthly inspections by personnel, further reducing operating costs.

[0103] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made using the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for treating wastewater from water quality testing, characterized in that, Includes the following steps: S10: Waste liquid generated during water quality testing shall be collected separately from at least three categories: chromium-containing waste liquid, organic reagent-containing waste liquid, and acidic waste liquid; S20: Treat the chromium-containing waste liquid to produce an iron-containing solution rich in iron ions, and then use the collected acidic waste liquid to adjust the iron-containing solution to a predetermined pH range before storing it; S30: Use the stored iron-containing solution as a catalyst to treat the waste liquid containing organic reagents.

2. The processing method as described in claim 1, characterized in that, Step S20 is performed as follows: S201: The chromium-containing waste liquid is pumped into the electrochemical reduction reactor and an electrochemical reaction is carried out; S202: Transfer the solution treated in step 201 to the primary mixing tank and adjust the pH of the primary mixing tank to 4.0-5.5; S203: Transfer the solution to the precipitation reaction tank, add alkaline solution and selective precipitation aid, and adjust the pH to 8.0-9.0 to form Cr(OH)3 precipitate; S204: Solid-liquid separation forms an iron-rich solution and chromium-containing sludge. S205: Transfer the iron-containing solution to a storage tank and inject acidic waste liquid into the storage tank to adjust the pH to a predetermined range.

3. The processing method as described in claim 2, characterized in that, Step S30 is performed as follows: S301: Pump the organic waste liquid to be treated into the electric Fenton reactor; S302: Based on the initial chemical oxygen demand (COD) concentration of the organic waste liquid to be treated, according to the preset Fe... 2+ COD molar ratio, injecting iron-containing solution into the electro-Fenton reactor; S303: Adjust the pH to 2.5-3.5; S304: Performs electro-Fenton advanced oxidation reactions; S305: Solid-liquid separation forms effluent and iron-containing sludge.

4. The processing method as described in claim 3, characterized in that, Step S10 also includes collecting alkaline waste liquid, and the alkaline solution added in step S203 is alkaline waste liquid.

5. The processing method as described in claim 4, characterized in that, The predetermined range mentioned in step 205 is PH2.0-3.

5.

6. The processing method as described in claim 4, characterized in that, In step S303, when adjusting the pH, the acidic waste liquid collected in step S10 is added to adjust the pH.

7. The processing method as described in claim 4, characterized in that, Step 305 further includes transferring the solution from the electro-Fenton advanced oxidation reaction to a neutralization flocculation tank, adding alkali and flocculant, wherein the alkali added is an alkaline waste liquid.

8. The processing method as described in claim 7, characterized in that, In step 305, an alkaline solution is added to adjust the pH to pH 7-8, and the flocculant is polyacrylamide.

9. The processing method as described in claim 7, characterized in that, In step 203, the selective precipitation aid may be sodium carbonate, and after step 203, a flocculant may be added, which may be polyacrylamide.

10. A wastewater treatment system for an automatic water quality monitoring station, characterized in that, include: The sorting and collection unit includes at least three independent waste liquid collection containers, which are used to collect chromium-containing waste liquid, organic reagent-containing waste liquid, and acidic waste liquid, respectively. A chromium-containing waste liquid treatment unit, connected to the chromium-containing waste liquid collection container, includes an electrochemical reduction reactor, a precipitation device and a first solid-liquid separation module, for treating the chromium-containing waste liquid and producing an iron-containing solution rich in iron ions. The chromium-containing waste liquid treatment unit also includes a storage tank for storing the iron-containing solution. An organic reagent waste liquid treatment unit, connected to the organic reagent waste liquid collection container, is configured to treat the organic reagent waste liquid using a stored iron-containing solution as a catalyst.

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