Comprehensive treatment and recycling system for cabin washing wastewater of multi-chemical cabin washing station

Abstract

The utility model relates to a comprehensive treatment and recycling system for cabin washing wastewater of a multi-chemical cabin washing station, which comprises an acid-alkali wastewater pretreatment device, a benzene wastewater pretreatment device, an oil-containing wastewater pretreatment device, an alcohol wastewater treatment device and a domestic sewage pretreatment device, the acid-base wastewater pretreatment device, the benzene wastewater pretreatment device, the oil-containing wastewater pretreatment device, the alcohol wastewater treatment device and the domestic sewage pretreatment device are all connected with the comprehensive wastewater treatment device; the tank washing wastewater is classified and collected from a wastewater source path, and a targeted pretreatment process is adopted according to the physicochemical characteristics of each type of wastewater, so that the pressure of subsequent comprehensive treatment is greatly relieved, the stability and reliability of the treatment effect are guaranteed, and meanwhile, the wide applicability of the process is also improved; the pretreated comprehensive wastewater is subjected to a biochemical and advanced oxidation process, so that the economical efficiency of system operation and the final effluent effect are ensured.

Description

Technical Field

[0001] This utility model relates to the field of waste liquid treatment technology, and in particular to a comprehensive treatment and reuse system for wastewater from tank cleaning stations using various chemicals. Background Technology

[0002] In recent years, with the rapid development of the Yangtze River shipping and petrochemical industry, the variety and quantity of chemical transported have continued to increase. The transshipment of chemical tankers at inland port terminals has become increasingly common. The mixing of different types of cargo not only affects cargo quality but also poses significant safety hazards to vessel navigation. However, most inland chemical tankers do not carry tank cleaning equipment and must undergo centralized cleaning at specialized chemical tanker cleaning stations. This results in a wide variety of chemicals in the wastewater generated at these stations, such as benzene, alcohols, edible oils, acids, and alkalis. The wastewater characteristics vary considerably and are difficult to treat. Furthermore, the randomness of the tank cleaning time leads to fluctuations in wastewater quality and quantity.

[0003] Traditional tank cleaning wastewater treatment processes typically involve a combination of physical-chemical and biological treatments before direct discharge. However, when the wastewater contains multiple toxic and harmful substances, this process often struggles to treat all organic matter to the required standards, or the standards are inconsistent, failing to achieve reliable and safe treatment. Furthermore, under the current trend of energy conservation and emission reduction, wastewater reuse is also a growing societal trend. However, the pretreatment of tank cleaning wastewater inevitably produces salts during physical-chemical treatment. When the reuse rate is only 70%, prolonged operation leads to salt accumulation in the system, significantly impacting the system, equipment, and pipelines. This also results in poor tank cleaning performance and prevents repeated recycling. Utility Model Content

[0004] The purpose of this invention is to overcome the defects in the existing technology and provide a comprehensive treatment and reuse system for wastewater from tank cleaning stations using various chemicals.

[0005] To achieve the above objectives, the technical solution of this utility model is to design a comprehensive treatment and reuse system for wastewater from multiple chemical tank cleaning stations, including a pretreatment device for acid and alkali wastewater, a pretreatment device for benzene wastewater, a pretreatment device for oily wastewater, a treatment device for alcohol wastewater, and a pretreatment device for domestic sewage. The acid and alkali wastewater pretreatment device, the benzene wastewater pretreatment device, the oily wastewater pretreatment device, the alcohol wastewater treatment device, and the domestic sewage pretreatment device are all connected to the comprehensive wastewater treatment device.

[0006] The acid and alkali wastewater pretreatment device includes an alkali wastewater storage tank and an acid wastewater storage tank. The outlets of the alkali wastewater storage tank and the acid wastewater storage tank are sequentially connected to a fully automatic neutralization and equalization tank, a first coagulation sedimentation tank, a pH equalization tank, a high-pressure reverse osmosis system, and an evaporation crystallization system.

[0007] The benzene wastewater pretreatment device includes a benzene wastewater storage tank, and the outlet of the benzene wastewater storage tank is sequentially connected to a first oil separator, an air flotation tank, a Fenton oxidation tank, and a second coagulation sedimentation tank.

[0008] The oily wastewater pretreatment device includes an oily wastewater collection tank, and the outlet of the oily wastewater collection tank is sequentially connected to a second oil separator and a two-stage air flotation tank.

[0009] The domestic sewage pretreatment device includes a bar screen well, which is connected to the inlet of the domestic sewage collection tank, and a bar screen cleaning machine is installed inside the bar screen well;

[0010] The alcohol wastewater treatment device includes an alcohol wastewater storage tank, which is connected to a comprehensive equalization tank;

[0011] The integrated wastewater treatment device includes an integrated equalization tank, which is sequentially connected to a hydrolysis acidification tank, a PTA2O tank, an MBR membrane tank, an ozone oxidation tank, and a clear water tank according to the order in which the wastewater flows. The inlet of the integrated equalization tank is connected to the condensate outlet of the evaporation crystallization system, the product water outlet of the high-pressure reverse osmosis system, the outlet of the second coagulation sedimentation tank, the outlet of the two-stage air flotation tank, the outlet of the alcohol wastewater storage tank, and the outlet of the domestic sewage collection tank.

[0012] In a further preferred embodiment, the fully automatic neutralization and equalization tank is connected to a first sodium hydroxide dosing device for adjusting the pH of the wastewater; the first coagulation and sedimentation tank is connected to a first PAC dosing device and a first PAM dosing device; the pH equalization tank is connected to a first sulfuric acid dosing device; each of the fully automatic neutralization and equalization tank, the first coagulation and sedimentation tank, and the pH equalization tank is equipped with a stirring device; the sludge discharge port of the first coagulation and sedimentation tank is equipped with a first sludge discharge pump to transport the settled sludge to the physicochemical sludge tank; the high-pressure reverse osmosis system uses a butterfly-tube membrane module connected to the evaporation and crystallization system and the integrated equalization tank, and is also connected to a scale inhibitor dosing device and a reducing agent dosing device.

[0013] In a further preferred embodiment, the first oil separator is equipped with an oil skimming device at its top; the dissolved air flotation (DAF) tank adopts a dissolved air flotation method, and a first intermediate water tank is provided between the DAF tank and the Fenton oxidation tank; the DAF tank is connected to a second sodium hydroxide dosing device, a second PAC dosing device, and a second PAM dosing device; the second coagulation sedimentation tank is connected to a second sodium hydroxide dosing device and a second PAM dosing device; the Fenton oxidation tank is connected to a second sulfuric acid dosing device, a hydrogen peroxide dosing device, and a ferrous sulfate dosing device; the second coagulation sedimentation tank is equipped with a stirring device; the DAF tank and the second coagulation sedimentation tank are respectively equipped with a first slag discharge pump and a second sludge discharge pump to transport scum and sludge to a physicochemical sludge tank.

[0014] In a further preferred embodiment, the top of the second oil separator is equipped with an oil skimming device; the two-stage flotation tank adopts a combination of a vortex flotation tank and a dissolved air flotation tank, and both the vortex flotation tank and the dissolved air flotation tank are connected to a third sodium hydroxide dosing device, a third PAC dosing device, and a third PAM dosing device; the vortex flotation tank and the dissolved air flotation tank are respectively equipped with a second sludge discharge pump and a third sludge discharge pump to transport the sludge to the physicochemical sludge tank.

[0015] In a further preferred embodiment, both the integrated conditioning tank and the hydrolysis acidification tank are equipped with submersible agitators; both the PTA2O tank and the MBR membrane tank are equipped with aeration devices at the bottom, which are connected to a second blower; both the hydrolysis acidification tank and the PTA2O tank are equipped with elastic packing material; the MBR membrane tank is equipped with membrane modules; and an ozone generator is located next to the ozone oxidation tank and connected to the aeration disc at the bottom of the ozone oxidation tank.

[0016] A further preferred technical solution also includes a deep treatment device, which includes a multi-media filter connected to the outlet of the ozone oxidation tank, and the multi-media filter is sequentially connected to an activated carbon filter, a disinfection tank, and a greywater collection tank.

[0017] In a further preferred embodiment, a second intermediate water tank is provided between the ozone oxidation tank and the multi-media filter; the disinfection tank is connected to a sodium hypochlorite dosing device for adding disinfectant; the multi-media filter uses two media, pebbles and quartz sand, with a filtration rate of 15-20 m / h; the activated carbon filter uses virgin fruit shell activated carbon as the filter media, with a filtration rate of 15-20 m / h.

[0018] A further preferred technical solution also includes a sludge treatment device, which comprises a physicochemical sludge tank, a biological sludge tank, a plate and frame filter press, and a screw press dewatering machine; the sludge inlet of the physicochemical sludge tank is connected to the sludge outlet of the first coagulation sedimentation tank, the sludge outlet of the dissolved air flotation tank, the sludge outlet of the second coagulation sedimentation tank, and the sludge outlet of the two-stage dissolved air flotation tank; the sludge outlet of the physicochemical sludge tank is equipped with a first sludge conveying pump connected to the sludge inlet of the plate and frame filter press; the sludge inlet of the biological sludge tank is connected to the sludge outlets of the hydrolysis acidification tank, the PTA2O tank, and the MBR membrane tank; the sludge outlet of the biological sludge tank is equipped with a second sludge conveying pump connected to the sludge inlet of the screw press dewatering machine.

[0019] A comprehensive treatment and reuse process for tank cleaning wastewater from a multi-chemical tank cleaning station includes a comprehensive treatment and reuse system for tank cleaning wastewater from a multi-chemical tank cleaning station. The system first classifies the tank cleaning wastewater and pre-treats it according to the wastewater category. After pre-treatment, the various types of wastewater undergo comprehensive treatment to ensure that the wastewater meets discharge standards.

[0020] The wastewater from the tank cleaning process includes acidic and alkaline wastewater, benzene-based wastewater, oily wastewater, alcohol-based wastewater, and domestic sewage.

[0021] The pretreatment adopts a physicochemical method to remove oil, suspended solids, solid impurities, total dissolved solids and non-biodegradable organic matter from the wastewater;

[0022] The wastewater comprehensive treatment adopts a biochemical + advanced oxidation process.

[0023] In a further preferred embodiment, part of the effluent generated during the comprehensive wastewater treatment process undergoes advanced treatment to remove pollutants such as COD, SS, and coliform bacteria, thereby meeting the standards for reuse in tank cleaning.

[0024] The physicochemical sludge and biochemical sludge generated during the comprehensive wastewater treatment process enter the sludge treatment unit for classification, collection, and dewatering.

[0025] A further preferred technical solution is that the pretreatment of acidic and alkaline wastewater includes storing acidic and alkaline wastewater, neutralizing acidic and alkaline wastewater, then performing coagulation and sedimentation to form sediment separation, adjusting the pH value of the separated wastewater, and then concentrating the pH-adjusted wastewater through a high-pressure reverse osmosis system.

[0026] The benzene wastewater pretreatment includes the storage of benzene wastewater, oil separation and suspended solids removal, oxidation of recalcitrant organic matter to remove COD, and flocculation reaction.

[0027] The pretreatment of oily wastewater includes the storage of benzene-containing wastewater, oil separation and removal of suspended solids from the benzene-containing wastewater, oxidation of recalcitrant organic matter to remove COD, and flocculation reaction.

[0028] After being screened for slag removal, the biochemical wastewater enters the biochemical wastewater collection tank and then directly enters the comprehensive equalization tank for comprehensive treatment. Alcohol wastewater can provide a carbon source for subsequent biochemical reactions. After being collected in the storage tank, it is quantitatively pumped into the comprehensive equalization tank.

[0029] The integrated wastewater treatment process includes homogenizing the wastewater in a comprehensive equalization tank, then subjecting it to anaerobic treatment in a hydrolysis acidification tank to remove most of the organic matter and improve the biodegradability of the wastewater, and finally subjecting it to decolorization and deodorization in an ozone oxidation tank under the action of ozone oxidation, ultimately achieving the required discharge standards.

[0030] After the above treatment, the wastewater discharge standards are: CODcr ≤ 300 mg / L, BOD5 ≤ 200 mg / L, SS ≤ 100 mg / L, TN ≤ 15 mg / L, TP ≤ 3 mg / L, ammonia nitrogen ≤ 5 mg / L, and pH value: 6~9. The reclaimed water quality meets the "washing water" standard in "Water Quality Standard for Industrial Water Reuse of Urban Wastewater" (GB / T 19923-2024), namely: CODcr ≤ 50 mg / L, BOD5 ≤ 10 mg / L, petroleum hydrocarbons ≤ 1.0 mg / L, total hardness ≤ 450 mg / L, total residual: 0.1~0.2 mg / L, color 20, fecal coliforms ≤ 1000 (CFU / L), and pH value: 6~9.

[0031] The advantages and beneficial effects of this utility model are as follows: This utility model classifies and collects tank cleaning wastewater from its source path and adopts targeted pretreatment processes based on the physicochemical characteristics of each type of wastewater, which greatly alleviates the pressure of subsequent comprehensive treatment, ensures the stability and reliability of the treatment effect, and also improves the wide applicability of the process; the comprehensive wastewater after pretreatment adopts a biochemical + advanced oxidation process to ensure the economic efficiency of the system operation and the final effluent effect; finally, part of the effluent after comprehensive treatment is further treated by a filtration + disinfection process for deep treatment, so that it can be reused for tank cleaning, reducing the excessive consumption of freshwater resources during tank cleaning. This process method not only ensures the treatment effect of various chemical tank cleaning wastewater, but also achieves the goal of energy conservation and emission reduction.

[0032] This invention employs a combined high-pressure reverse osmosis system and an evaporation crystallization system for the pretreatment of acidic and alkaline wastewater. This method solves the problems of large amounts of salts generated during the treatment of acidic and alkaline wastewater and the accumulation of salts due to the reuse of treated water, thus mitigating the adverse effects on the system, equipment, and pipelines. For the pretreatment of oily wastewater, a two-stage flotation system consisting of a vortex flotation tank and a dissolved air flotation tank is used, improving the removal rates of petroleum hydrocarbons, COD, and suspended solids in the wastewater and reducing the difficulty of subsequent treatment. The floating oil and crystalline salts generated in some process stages can be recovered, possessing high economic value. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the acid and alkali wastewater pretreatment device of this utility model;

[0034] Figure 2 This is a schematic diagram of the benzene-based wastewater pretreatment device of this utility model;

[0035] Figure 3 This is a schematic diagram of the oily wastewater pretreatment device of this utility model;

[0036] Figure 4 This is a schematic diagram of the domestic sewage pretreatment device of this utility model;

[0037] Figure 5 This is a schematic diagram of the alcohol wastewater pretreatment device of this utility model;

[0038] Figure 6 This is a schematic diagram of the integrated wastewater treatment device of this utility model;

[0039] Figure 7 This is a schematic diagram of the sludge treatment device of this utility model;

[0040] Figure 8 This is a process flow diagram of the present invention;

[0041] In the diagram: 100. Acid and alkali wastewater pretreatment device; 101. Alkaline wastewater storage tank; 102. Acid wastewater storage tank; 103. Fully automatic neutralization and equalization tank; 104. First coagulation sedimentation tank; 105. pH equalization tank; 106. High-pressure reverse osmosis system; 107. Evaporation crystallization system; 108. First sodium hydroxide dosing device; 109. First PAC dosing device; 110. First PAM dosing device; 111. First sulfuric acid dosing device; 112. Scale inhibitor dosing device; 113. Reducing agent dosing device.

[0042] 200. Benzene wastewater pretreatment device; 201. Benzene wastewater storage tank; 202. First oil separator; 203. Air flotation tank; 204. First intermediate water tank; 205. Fenton oxidation tank; 206. Second coagulation sedimentation tank; 207. Second sodium hydroxide dosing device; 208. Second PAC dosing device; 209. Second PAM dosing device; 210. Second sulfuric acid dosing device; 211. Hydrogen peroxide dosing device; 212. Ferrous sulfate dosing device; 213. First sludge pump; 214. First blower; 215. Perforated pipe; 216. Second sludge pump;

[0043] 300. Oily wastewater pretreatment device; 301. Oily wastewater collection tank; 302. Second oil separator; 303. Two-stage dissolved air flotation tank; 3031. Vortex dissolved air flotation tank; 3032. Dissolved air flotation tank; 304. Third sodium hydroxide dosing device; 305. Third PAC dosing device; 306. Third PAM dosing device; 307. Second slag discharge pump; 308. Third slag discharge pump;

[0044] 400. Domestic sewage pretreatment device; 401. Bar screen well; 402. Bar screen cleaning machine; 403. Domestic sewage collection tank;

[0045] 500. Alcohol wastewater pretreatment device; 501. Alcohol wastewater storage tank;

[0046] 600. Integrated wastewater treatment unit; 601. Integrated equalization tank; 602. Hydrolysis acidification tank; 603. PTA2O tank; 604. MBR membrane tank; 605. Ozone oxidation tank; 606. Clear water tank; 607. First submersible mixer; 608. Second submersible mixer; 609. Membrane module; 610. Ozone generator; 611. Aeration disc; 612. Second blower; 613. Sodium hypochlorite dosing device; 614. Second intermediate water tank; 615. Backwash pump; 616. Multi-media filter; 617. Activated carbon filter; 618. First disinfection tank; 619. Greywater collection tank;

[0047] 700. Sludge treatment unit; 701. Physicochemical sludge tank; 702. First sludge pump; 703. Plate and frame filter press; 704. Fourth PAM dosing device; 705. Biological sludge tank; 706. Second sludge pump; 707. Screw press dewatering machine. Detailed Implementation

[0048] The specific embodiments of this utility model will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solution of this utility model and should not be construed as limiting the scope of protection of this utility model.

[0049] Reference Figure 1-7 A comprehensive wastewater treatment and reuse system for tank cleaning stations using multiple chemicals includes an acid and alkali wastewater pretreatment device 100, a benzene wastewater pretreatment device 200, an oily wastewater pretreatment device 300, a domestic sewage pretreatment device 400, an alcohol wastewater pretreatment device 500, a comprehensive wastewater treatment device 600, a deep treatment device, and a sludge treatment device 700.

[0050] The acid and alkali wastewater pretreatment device includes an alkali wastewater storage tank 101 and an acid wastewater storage tank 102. The outlets of the alkali wastewater storage tank 101 and the acid wastewater storage tank 102 are sequentially connected to a fully automatic neutralization and equalization tank 103, a first coagulation and sedimentation tank 104, a pH adjustment tank 105, a high-pressure reverse osmosis system 106, and an evaporation and crystallization system 107. The fully automatic neutralization and equalization tank 103 is connected to a first sodium hydroxide dosing device 108 for adjusting the pH of the wastewater. The first coagulation and sedimentation tank 104 is connected to a first PAC dosing device 109 and a first PAM dosing device 110. The pH adjustment tank 105 is connected to a first sulfuric acid dosing device 111. The automatic neutralization and equalization tank 103, the first coagulation sedimentation tank 104, and the pH equalization tank 105 are all equipped with stirring devices; the first coagulation sedimentation tank 104 is equipped with a first sludge discharge pump 114 to transport the settled sludge to the physicochemical sludge tank 301; the high-pressure reverse osmosis system 106 adopts a butterfly tube membrane module, which uses cross-flow filtration to improve the filtration and separation capacity. The concentrated water and clean water after reverse osmosis are respectively connected to the evaporation crystallization system 107 and the comprehensive equalization tank 201. The high-pressure reverse osmosis system 106 is also connected to the scale inhibitor dosing device 112 and the reducing agent dosing device 113; the evaporation crystallization system 107 adopts a triple-effect evaporation system, and the produced crystallized salt can be transported off-site for disposal.

[0051] The benzene wastewater pretreatment device includes a benzene wastewater storage tank 201. The outlet of the benzene wastewater storage tank 201 is sequentially connected to a first oil separator 202, a dissolved air flotation (DAF) tank 203, a Fenton oxidation tank 205, and a second coagulation sedimentation tank 206. The top of the first oil separator 202 is equipped with an oil skimming device; when the oil layer reaches a certain thickness, the upper floating oil is skimmed into an oil collection tank for further disposal. The DAF tank 203 uses dissolved air flotation. A first intermediate water tank 204 is provided between the DAF tank 203 and the Fenton oxidation tank 205. The DAF tank 203 is connected to a second sodium hydroxide dosing device 207, a second PAC dosing device 208, and a second PAM dosing device 209. The second coagulation sedimentation tank... Tank 206 is connected to the second sodium hydroxide dosing device 207 and the second PAM dosing device 209; Fenton oxidation tank 205 is connected to the second sulfuric acid dosing device 210, hydrogen peroxide dosing device 211, and ferrous sulfate dosing device 212; the second coagulation sedimentation tank 206 is equipped with a stirring device for stirring reaction, and the bottom of the Fenton oxidation tank 205 is equipped with a perforated pipe 215, which uses air stirring to mix the wastewater, and the perforated pipe 215 is connected to the first blower 214; the flotation tank 203 is equipped with a first sludge discharge pump 213 to transport sludge to the physicochemical sludge tank 301; the second coagulation sedimentation tank 206 is equipped with a second sludge discharge pump 216 to transport sludge to the physicochemical sludge tank 701.

[0052] The oily wastewater pretreatment device 300 includes an oily wastewater collection tank 301, the outlet of which is sequentially connected to a second oil separator 302 and a two-stage dissolved air flotation tank 303. Further, the top of the second oil separator 302 is equipped with an oil skimming device; when the oil layer reaches a certain thickness, the upper floating oil is skimmed into an oil collection tank for further disposal. The two-stage dissolved air flotation tank 303 employs a vortex-type dissolved air flotation tank 3031 and a dissolved air flotation tank. The combination of tanks 3032 includes the vortex-induced flotation tank 3031 and the dissolved air flotation tank 3032, both of which are connected to the third sodium hydroxide dosing device 304, the third PAC dosing device 305, and the third PAM dosing device 306. The vortex-induced flotation tank 3031 is equipped with a second sludge discharge pump 307 to transport sludge to the physicochemical sludge tank 701. The dissolved air flotation tank 3032 is equipped with a third sludge discharge pump 308 to transport sludge to the physicochemical sludge tank 701.

[0053] The domestic sewage pretreatment device 400 includes a bar screen well 401, which is connected to the inlet of the domestic sewage collection tank 403; the bar screen well 401 is equipped with a bar screen cleaner 402, which is used to intercept larger solid impurities in the domestic sewage.

[0054] The alcohol wastewater pretreatment device 500 includes an alcohol wastewater storage tank 501, which collects and connects to a comprehensive equalization tank 601.

[0055] The top of both the benzene wastewater storage tank 201 and the alcohol wastewater storage tank 501 is equipped with a breather valve and sealed with nitrogen to increase the safety of the tanks. The remaining tanks are equipped with breather valves to ensure the safety of the tank body.

[0056] The integrated wastewater treatment device 600 includes an integrated regulating tank 601, which is sequentially connected to a hydrolysis acidification tank 602, a PTA2O tank 603, an MBR membrane tank 604, an ozone oxidation tank 605, and a clear water tank 606 according to the wastewater flow sequence. The inlet of the integrated regulating tank 601 is connected to the condensate outlet of the evaporation crystallization system 107, the product water outlet of the high-pressure reverse osmosis system 106, the outlet of the second coagulation sedimentation tank 206, the outlet of the two-stage air flotation tank 303, the outlet of the alcohol wastewater storage tank 501, and the outlet of the domestic sewage collection tank 403.

[0057] The integrated conditioning tank 601 is equipped with a first submersible agitator 607; the hydrolysis acidification tank 602 is equipped with a second submersible agitator 608; both the PTA2O tank 603 and the MBR membrane tank 604 are equipped with aeration devices at the bottom, which are connected to a second blower 612; both the hydrolysis acidification tank 602 and the PTA2O tank 603 are equipped with elastic packing material to achieve microbial enrichment and improve treatment efficiency; the MBR membrane tank 604 is equipped with a membrane module 609, which uses an oil-resistant flat sheet membrane to extend its service life; an ozone generator 610 is provided next to the ozone oxidation tank 605 to generate ozone and is connected to the aeration disc 611 at the bottom of the ozone oxidation tank 605; the water after ozone oxidation enters the clear water tank 606 and is discharged in compliance with standards.

[0058] The advanced treatment device includes a multi-media filter 616 connected to the outlet of the ozone oxidation tank 605, which in turn includes an activated carbon filter 617, a disinfection tank 618, and a greywater collection tank 619. A second intermediate water tank 614 is provided between the ozone oxidation tank 605 and the multi-media filter 616. When the multi-media filter 616 and the activated carbon filter 617 become clogged after long-term use, a backwash pump 615 pumps water from the second intermediate water tank 614 to backwash the filters. The disinfection tank 618 is connected to a sodium hypochlorite dosing device 613 for adding disinfectant, which further disinfects the filtered greywater to ensure that the effluent meets the standards. The multi-media filter 616 uses two media, pebbles and quartz sand, with a filtration rate of 15-20 m / h. The activated carbon filter 617 uses virgin fruit shell activated carbon as the filter media, with a filtration rate of 15-20 m / h.

[0059] The sludge treatment unit 700 includes a physicochemical sludge tank 701, a biological sludge tank 705, a plate and frame filter press 703, and a screw press dewatering machine 707. The sludge inlet of the physicochemical sludge tank 701 is connected to the sludge outlet of the first coagulation sedimentation tank 104, the sludge outlet of the dissolved air flotation tank 203, the sludge outlet of the second coagulation sedimentation tank 206, and the sludge outlet of the two-stage dissolved air flotation tank 303, respectively. The sludge outlet of the physicochemical sludge tank 701 is equipped with a first sludge conveying pump 702 connected to the sludge inlet of the plate and frame filter press 703. The sludge inlet of the biological sludge tank 705 is connected to the hydrolysis acidification tank 602, the PTA2O tank 603, and the MBR membrane tank 607. The sludge outlet of the 4 is connected; the sludge outlet of the biochemical sludge tank 705 is equipped with a second sludge conveying pump 706 connected to the sludge inlet of the screw press dewatering machine 707; the plate and frame filter press 703 and the screw press dewatering machine 707 are connected to a fourth PAM dosing device 704 for adding coagulant aid to improve dewatering efficiency, and the dewatered sludge cake is transported off-site for disposal; the filtrate outlet of the plate and frame filter press 703 and the screw press dewatering machine 707 is connected to the integrated equalization tank 601.

[0060] Reference Figure 8A comprehensive treatment and reuse process for tank cleaning wastewater from a multi-chemical tank cleaning station is proposed. First, the tank cleaning wastewater is classified and pre-treated according to its category. After pre-treatment, the various types of wastewater are further treated to ensure that the wastewater meets discharge standards.

[0061] Specifically, the wastewater from the tank cleaning process includes acidic and alkaline wastewater, benzene-based wastewater, oily wastewater, alcohol-based wastewater, and domestic sewage.

[0062] The pretreatment adopts a physicochemical method to remove oil, suspended solids, solid impurities, total dissolved solids and non-biodegradable organic matter from the wastewater.

[0063] The wastewater treatment employs a biochemical + advanced oxidation process.

[0064] The wastewater generated during the wastewater treatment process undergoes advanced treatment to remove pollutants such as COD, SS, and coliform bacteria, meeting the standards for reuse in tank cleaning.

[0065] The physicochemical sludge and biochemical sludge generated during the wastewater treatment process enter the sludge treatment unit for classification, collection, and dewatering.

[0066] The acid and alkali wastewater pretreatment includes storing the acid and alkali wastewater, neutralizing the acid and alkali wastewater, then performing coagulation and sedimentation to form sediment separation, adjusting the pH value of the separated wastewater, and then concentrating the pH-adjusted wastewater through a high-pressure reverse osmosis system.

[0067] Specifically, acidic and alkaline wastewater is collected and pumped to a fully automatic neutralization and equalization tank 103. After neutralization, alkaline solution is added as needed to control the pH of the wastewater between 8 and 9. The adjusted wastewater then enters the first coagulation and sedimentation tank 104, where PAC and PAM are added to carry out coagulation and flocculation reactions. After sedimentation and separation, suspended solids and large particles in the wastewater are removed. The supernatant flows by gravity to the pH equalization tank 105, where sulfuric acid is added to adjust the pH of the wastewater to neutral. The supernatant is then pumped into the high-pressure reverse osmosis system 106 for concentration. The concentrate produced by the high-pressure reverse osmosis system 106 enters the subsequent evaporation and crystallization system 107 for desalination treatment. The resulting crystallized salt is packaged and transported for disposal. The permeate from the high-pressure reverse osmosis system 106 and the condensate from the evaporation and crystallization system 107 enter the comprehensive equalization tank 601, awaiting subsequent biological treatment.

[0068] The benzene wastewater pretreatment includes the storage of benzene wastewater, oil separation and removal of suspended solids, oxidation of recalcitrant organic matter to remove COD, and flocculation reaction.

[0069] Specifically, after collection, benzene-containing wastewater undergoes an oil-water separation and air flotation process to effectively remove water-insoluble benzene pollutants and suspended solids. It then proceeds to the Fenton oxidation tank 205 for further treatment. Under the action of sulfuric acid, the pH of the wastewater is adjusted to between 3 and 4. Hydrogen peroxide and ferrous sulfate are then added to oxidize recalcitrant organic matter using advanced oxidation principles, achieving COD removal. After oxidation treatment, the wastewater flows to the second coagulation sedimentation tank 206, where sodium hydroxide and PAM are added for flocculation, further removing COD and suspended solids. The supernatant after sedimentation enters the comprehensive equalization tank 601, awaiting subsequent biological treatment.

[0070] The pretreatment of oily wastewater includes the storage of benzene-containing wastewater, oil separation and removal of suspended solids from the benzene-containing wastewater, followed by oxidation of recalcitrant organic matter to remove COD, and then flocculation reaction.

[0071] Specifically, after collection, the oily wastewater first enters the second oil separator 302 for skimming and collection of floating oil, and then enters the two-stage air flotation tank 303 for emulsified oil treatment. By adding agents such as sodium hydroxide, PAC, and PAM, a coagulation reaction is carried out, which can effectively remove pollutants such as COD, suspended solids, and metal ions from the wastewater. The upper layer of scum is skimmed off by a scum scraper, and the lower layer of clear water is discharged into the comprehensive equalization tank 601, awaiting subsequent biological treatment.

[0072] After being screened to remove slag, the biochemical wastewater enters the biochemical wastewater collection tank 403. Because domestic sewage has good biodegradability, it can be directly sent to the comprehensive regulating tank 601 for comprehensive treatment. Alcohol wastewater can provide carbon source for subsequent biochemical reactions, so it is collected in a storage tank and quantitatively pumped into the comprehensive regulating tank 601.

[0073] The integrated wastewater treatment process includes homogenizing the wastewater in a comprehensive equalization tank 601, then subjecting it to anaerobic treatment in a hydrolysis acidification tank 602 to remove most of the organic matter and improve the biodegradability of the wastewater, and finally decolorizing and deodorizing it in an ozone oxidation tank 605 under the action of ozone oxidation, ultimately achieving the discharge standard.

[0074] Specifically, the pretreated wastewater from various tank washing operations and domestic sewage is homogenized and equalized in the integrated equalization tank 601, and then enters the hydrolysis acidification tank 602 for anaerobic treatment to remove most of the organic matter and improve the biodegradability of the wastewater. The hydrolysis acidification wastewater enters the PTA2O tank 603 for decarbonization, nitrification, and denitrification reactions, and sludge-water separation. The supernatant enters the MBR membrane tank 604 for further treatment. Finally, the wastewater enters the ozone oxidation tank 605 for decolorization and deodorization under the action of ozone oxidation, and finally meets the discharge standards.

[0075] The advanced treatment includes pumping a portion of the wastewater after ozone oxidation (with a reuse rate of 60%) into a multi-media filter 616 and an activated carbon filter 617 to further remove suspended solids, grease, COD, etc. from the wastewater; the filtered wastewater enters a disinfection tank 617, and is reused after disinfection to meet the reuse standards.

[0076] The sludge treatment includes physical and chemical sludge from the sedimented sludge produced by the first coagulation sedimentation tank 104 and the second coagulation sedimentation tank 206, as well as scum produced by the dissolved air flotation tank 203 and the two-stage dissolved air flotation tank 303; and biological sludge from the excess sludge produced by the hydrolysis acidification tank 602, the PTA20 tank 603 and the MBR membrane tank 604.

[0077] Due to the differences in the structural properties of physicochemical sludge and biological sludge, in order to achieve better dewatering effect, physicochemical sludge is dewatered using a plate and frame filter press 703, while biological sludge is dewatered using a screw press 707. The filtrate after dewatering is returned to the integrated equalization tank 601 for further integrated treatment, while the dry sludge is transported off-site for disposal.

[0078] The wastewater discharge standards of this invention are: CODcr ≤ 300 mg / L, BOD5 ≤ 200 mg / L, SS ≤ 100 mg / L, TN ≤ 15 mg / L, TP ≤ 3 mg / L, ammonia nitrogen ≤ 5 mg / L, and pH value: 6~9. The reclaimed water quality meets the "washing water" standard in the "Water Quality Standard for Industrial Water Reuse of Urban Wastewater" (GB / T 19923-2024), namely: CODcr ≤ 50 mg / L, BOD5 ≤ 10 mg / L, petroleum hydrocarbons ≤ 1.0 mg / L, total hardness ≤ 450 mg / L, total residual: 0.1~0.2 mg / L, color 20, fecal coliforms ≤ 1000 (CFU / L), and pH value: 6~9.

[0079] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A comprehensive treatment and reuse system for wastewater from tank cleaning stations using multiple chemicals, characterized in that, It includes a pretreatment device for acid and alkali wastewater, a pretreatment device for benzene wastewater, a pretreatment device for oily wastewater, a treatment device for alcohol wastewater, and a pretreatment device for domestic sewage. The pretreatment devices for acid and alkali wastewater, benzene wastewater, oily wastewater, alcohol wastewater, and domestic sewage are all connected to a comprehensive wastewater treatment device. The acid and alkali wastewater pretreatment device includes an alkali wastewater storage tank and an acid wastewater storage tank. The outlets of the alkali wastewater storage tank and the acid wastewater storage tank are sequentially connected to a fully automatic neutralization and equalization tank, a first coagulation sedimentation tank, a pH equalization tank, a high-pressure reverse osmosis system, and an evaporation crystallization system. The benzene wastewater pretreatment device includes a benzene wastewater storage tank, and the outlet of the benzene wastewater storage tank is sequentially connected to a first oil separator, an air flotation tank, a Fenton oxidation tank, and a second coagulation sedimentation tank. The oily wastewater pretreatment device includes an oily wastewater collection tank, and the outlet of the oily wastewater collection tank is sequentially connected to a second oil separator and a two-stage air flotation tank. The domestic sewage pretreatment device includes a bar screen well, which is connected to the inlet of the domestic sewage collection tank, and a bar screen cleaning machine is installed inside the bar screen well; The alcohol wastewater treatment device includes an alcohol wastewater storage tank, which is connected to a comprehensive equalization tank; The integrated wastewater treatment device includes an integrated equalization tank, which is sequentially connected to a hydrolysis acidification tank, a PTA2O tank, an MBR membrane tank, an ozone oxidation tank, and a clear water tank according to the order in which the wastewater flows. The inlet of the integrated equalization tank is connected to the condensate outlet of the evaporation crystallization system, the product water outlet of the high-pressure reverse osmosis system, the outlet of the second coagulation sedimentation tank, the outlet of the two-stage air flotation tank, the outlet of the alcohol wastewater storage tank, and the outlet of the domestic sewage collection tank.

2. The comprehensive treatment and reuse system for tank cleaning wastewater from a multi-chemical tank cleaning station according to claim 1, characterized in that, The fully automatic neutralization and equalization tank is connected to the first sodium hydroxide dosing device for adjusting the pH of the wastewater; the first coagulation sedimentation tank is connected to the first PAC dosing device and the first PAM dosing device; the pH equalization tank is connected to the first sulfuric acid dosing device; the fully automatic neutralization and equalization tank, the first coagulation sedimentation tank, and the pH equalization tank are all equipped with stirring devices; the sludge discharge port of the first coagulation sedimentation tank is equipped with a first sludge discharge pump to transport the settled sludge to the physicochemical sludge tank; the high-pressure reverse osmosis system uses a butterfly tube membrane module connected to the evaporation crystallization system and the integrated equalization tank, and is also connected to a scale inhibitor dosing device and a reducing agent dosing device.

3. The comprehensive treatment and reuse system for tank cleaning wastewater from a multi-chemical tank cleaning station according to claim 1, characterized in that, The first oil separator is equipped with an oil skimming device at the top; the dissolved air flotation tank adopts the dissolved air flotation method, and a first intermediate water tank is provided between the dissolved air flotation tank and the Fenton oxidation tank; the dissolved air flotation tank is connected to a second sodium hydroxide dosing device, a second PAC dosing device, and a second PAM dosing device; the second coagulation sedimentation tank is connected to a second sodium hydroxide dosing device and a second PAM dosing device; the Fenton oxidation tank is connected to a second sulfuric acid dosing device, a hydrogen peroxide dosing device, and a ferrous sulfate dosing device; the second coagulation sedimentation tank is equipped with a stirring device; the dissolved air flotation tank and the second coagulation sedimentation tank are respectively equipped with a first slag discharge pump and a second sludge discharge pump to transport scum and sludge to a physicochemical sludge tank.

4. The comprehensive treatment and reuse system for tank cleaning wastewater from a multi-chemical tank cleaning station according to claim 1, characterized in that, The top of the second oil separator is equipped with an oil skimming device; the two-stage flotation tank adopts a combination of vortex flotation tank and dissolved air flotation tank, and both the vortex flotation tank and the dissolved air flotation tank are connected to the third sodium hydroxide dosing device, the third PAC dosing device and the third PAM dosing device; the vortex flotation tank and the dissolved air flotation tank are respectively equipped with a second sludge discharge pump and a third sludge discharge pump to transport the sludge to the physicochemical sludge tank.

5. A comprehensive treatment and reuse system for tank cleaning wastewater from a multi-chemical tank cleaning station according to claim 1, characterized in that, Submersible agitators are installed in both the integrated conditioning tank and the hydrolysis acidification tank; aeration devices are installed at the bottom of both the PTA2O tank and the MBR membrane tank, and the aeration devices are connected to the second blower; elastic packing is installed in both the hydrolysis acidification tank and the PTA2O tank; membrane modules are installed in the MBR membrane tank; and an ozone generator is installed next to the ozone oxidation tank and connected to the aeration disc at the bottom of the ozone oxidation tank.

6. A comprehensive treatment and reuse system for tank cleaning wastewater from a multi-chemical tank cleaning station according to any one of claims 1-5, characterized in that, It also includes a deep treatment device, which includes a multi-media filter connected to the outlet of the ozone oxidation tank. The multi-media filter is sequentially connected to an activated carbon filter, a disinfection tank, and a greywater collection tank. A second intermediate water tank is provided between the ozone oxidation tank and the multi-media filter. The disinfection tank is connected to a sodium hypochlorite dosing device for adding disinfectant. The multi-media filter uses two media, pebbles and quartz sand, with a filtration rate of 15-20 m / h; the activated carbon filter uses virgin fruit shell activated carbon as the filter media, with a filtration rate of 15-20 m / h.

7. A comprehensive treatment and reuse system for tank cleaning wastewater from a multi-chemical tank cleaning station according to any one of claims 1-5, characterized in that, It also includes a sludge treatment device, which comprises a physicochemical sludge tank, a biological sludge tank, a plate and frame filter press, and a screw press dewatering machine. The sludge inlet of the physicochemical sludge tank is connected to the sludge outlet of the first coagulation sedimentation tank, the sludge outlet of the dissolved air flotation tank, the sludge outlet of the second coagulation sedimentation tank, and the sludge outlet of the two-stage dissolved air flotation tank, respectively. The sludge outlet of the physicochemical sludge tank is equipped with a first sludge conveying pump connected to the sludge inlet of the plate and frame filter press. The sludge inlet of the biological sludge tank is connected to the sludge outlets of the hydrolysis acidification tank, the PTA2O tank, and the MBR membrane tank. The sludge outlet of the biological sludge tank is equipped with a second sludge conveying pump connected to the sludge inlet of the screw press dewatering machine.

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