Tanning main soaking water resourceful treatment device and treatment method

Abstract

The invention relates to a resourceful treatment device and a treatment method for leather-making main immersion water, aiming at the characteristics of large water amount, high pollutant concentration, complex components, high suspended solids and high salt content of the leather-making main immersion water, the method comprises the following steps: firstly, reducing the hardness, sulfate radicals and COD (Chemical Oxygen Demand) of the main immersion water by utilizing a primary reaction tank and a primary sedimentation tank; waste oil is recovered, COD and divalent salt are separated and concentrated through electrolytic flotation, a second-stage reaction tank, a second-stage sedimentation tank, an oil removal membrane, a material separation membrane and a two-stage NF membrane in sequence, and the waste oil and the divalent salt are returned to the front end for treatment; producing reuse water with TDS of less than or equal to 700 mg / L by using an ultrahigh pressure RO membrane, and concentrating sodium chloride to be more than or equal to 100000 mg / L; and finally, dilute acid and dilute alkali are produced by using a bipolar membrane, so that the aim of resourceful treatment of the tannery wastewater is fulfilled.

Description

Technical Field

[0001] The invention relates to a device and method for resource-based treatment of leather main soaking water, belonging to the technical field of industrial wastewater treatment. Background Art

[0002] The leather production process mainly includes three steps: (1) the preparation step, firstly, the hide is restored to the fresh state by soaking in water, the impurities on the hide are washed off, the subcutaneous tissue and fat on the hide are removed by fleshing, and then the hair on the hide is removed by depilation and liming to make the hide fiber moderately loose, and finally, the lime in the hide is removed by deliming and softening to reduce the pH value of the hide and further loosen the hide fiber; (2) the tanning step, firstly, the pH value of the hide is adjusted by acid immersion, and then, the collagen in the hide is combined with the tanning agent by tanning to improve the stability and water resistance of the hide, and finally, the quality and performance of the leather are further improved by retanning, that is, the fullness, softness and dyeing performance of the leather are increased; (3) the finishing step, firstly, the pH value of the leather is adjusted to 5-6 by neutralizing agent, and the desired color and softness are given to the leather by dyeing and fatliquoring to improve the quality and performance of the leather, and the moisture in the leather is removed by drying to make the leather reach a certain degree of dryness, and the leather surface is protected by coating to improve the gloss, wear resistance and water resistance of the leather.

[0003] The soaking treatment in the preparation stage of leather making is generally divided into two steps. The first step is pre-immersion, which removes the salt of the original hide preservative treatment and washes away the salt particles, blood stains, feces, soil and other impurities on the surface of the original hide; then the main soaking is added with fungicides, degreasing agents, sodium hydroxide and other soaking aids to make the original hide return to the appropriate water content and swelling degree and maintain its freshness. A large amount of main soaking water for leather making will be produced during the soaking process in the preparation stage of leather making. Here, the main soaking water for leather making is characterized by large water volume, high concentration of pollutants, complex composition, high suspended matter and high salt content. The pH value of the typical main soaking water for leather making is 8-10, COD (chemical oxygen demand) is 10000-20000mg / L, NH3-N (ammonia nitrogen) is 200-500mg / L, and TDS (total dissolved solids) is 20000-30000mg / L.

[0004] There are some patents for high-concentration, high-salt tanning wastewater, such as (1) Patent 201410544075.6 Tanning wastewater treatment method, which processes the tanning wastewater through screen sedimentation, reaction precipitation (adding PAC and polyaluminum flocculants), biological decomposition oxidation, secondary sedimentation, filtration, disinfection and then discharges it in compliance with the standards. The effluent quality is good, but the high salt content of the tanning wastewater is not solved; (2) Patent 201110044405.1 Tanning wastewater recycling device based on electrochemistry and ultrafiltration, which processes the tanning wastewater through pre-filtration, flocculation reaction, nano-catalytic electrolysis, precipitation, flotation, biochemical treatment, secondary nano-catalytic electrolysis, filtration and ultrafiltration in sequence, and the effluent is recycled, which is also limited by the salt content of the tanning wastewater. (3) 201810826347.X A tanning wastewater purification and desalination device, wherein the tanning wastewater is purified and desalinated in turn through a sedimentation tank, a wastewater storage tank, a chromium removal tank, a hardness removal tank, a gas removal unit and a reverse osmosis unit, so as to realize the recycling of the effluent. The process is simple, but the disadvantage is that the pre-treatment has poor effect on the treatment of oil and COD, and the reverse osmosis concentrated water is not treated; (4) 200920109967.8 A tanning wastewater desalination treatment device, for the tanning wastewater that has been biologically treated, by adding alkali and oxygen for high-temperature oxidation, secondary evaporation, water vapor reuse, cooling and crystallizing the saturated solution, and separating the solid salt. The disadvantage is that direct evaporation and crystallization consumes a lot of energy, and the solid salt is a mixed salt that cannot be used. Summary of the invention

[0005] The present invention provides a resource-based treatment device and method for leather main soaking water, which aims to solve the problems that leather main soaking water has the characteristics of large water volume, high pollutant concentration, complex composition, high suspended solids and high salt content, and the existing physical and chemical, biochemical and filtration treatment technologies have high salt content in the effluent, and reverse osmosis desalination cannot effectively treat reverse osmosis concentrated water, or evaporates and crystallizes impure salts, and cannot effectively recover salt resources; for leather with a pH value of 8-10, a COD of 10000-20000 mg / L, an NH3-N of 200-500 mg / L and a TDS of The main tanning water of 20000-30000 mg / L is firstly used in the primary reaction tank and the primary sedimentation tank to add lime, soda ash, PFS (polyferric sulfate), PAM (polyacrylamide), and powdered carbon to precipitate calcium carbonate and saturated calcium sulfate in the main tanning water, so that the hardness is ≤0.5mmol / L, sulfate ≤1800mg / L, and COD is 1500-3000mg / L, and then the pH value is adjusted back to 6-8 by adding hydrochloric acid; the second step is to use electrolytic flotation, secondary reaction tank and secondary sedimentation tank, and add The COD collector reduces the COD to 500-1000 mg / L; the third step uses the oil removal membrane to reduce the oil content to ≤100 mg / L, and collects the waste oil for further use; the fourth step uses the material separation membrane to separate and recover the COD, return it to the front-end treatment, and reduce the effluent COD to 150-300 mg / L, while protecting the material separation membrane by adding a reducing agent; the fifth step uses a two-stage NF (nanofiltration) membrane to effectively concentrate COD and divalent salt (sodium sulfate), return it to the front-end treatment, and the effluent COD ≤30 mg / L, divalent salt ≤20 mg / L, and at the same time, the two-stage NF membrane is protected by adding scale inhibitors and non-oxidizing bactericides; the sixth step is to use ultra-high pressure RO (reverse osmosis) membrane to produce recycled water with TDS ≤ 700mg / L, and concentrate the monovalent salt (sodium chloride) of the concentrated water to TDS ≥ 100000mg / L; finally, the BPED (bipolar membrane) device is used to produce dilute acid (HCl) and dilute alkali (NaOH) with a concentration of 2mol / L; ultimately, the water and salt resources in the main tanning water are effectively recovered, achieving the purpose of resource-based treatment of tanning wastewater and producing recycled water and dilute acid and alkali.

[0006] In order to solve the above technical problems, the present invention adopts the following technical scheme: The present invention provides a leather main soaking water resource treatment device, including: a raw water tank, a raw water pump, a primary reaction tank, a primary sedimentation tank, electrolytic flotation, a secondary reaction tank, a secondary sedimentation tank, a 1# clean water tank, a 1# clean water pump, an oil removal membrane device, a 2# clean water tank, a 2# clean water pump, a material separation membrane device, a 3# clean water tank, a 3# clean water pump, a two-stage nanofiltration system, a nanofiltration water production tank, a reverse osmosis booster pump, an ultra-high pressure reverse osmosis device, a reverse osmosis concentrated water tank, a bipolar membrane booster pump, a bipolar membrane device, a dilute acid tank, a dilute acid pump, a dilute alkali tank, a dilute alkali pump, a sludge box, a sludge pump, a plate and frame filter press, a concentrated oil tank, a concentrated oil pump, a 1# dosing device, a 2# dosing device, a 3# dosing device, and a 4# Dosing device, 5# dosing device, wastewater recovery tank, wastewater recovery pump, reverse osmosis water production tank and reverse osmosis water production pump; wherein the main immersion water is connected to the 1# water inlet of the raw water tank, the water outlet of the raw water tank is connected to the water inlet of the primary reaction tank through the raw water pump, the drug outlet of the 1# dosing device is connected to the drug inlet of the primary reaction tank, the water outlet of the primary reaction tank is connected to the water inlet of the primary sedimentation tank, the water outlet of the primary sedimentation tank is connected to the water inlet of the electrolytic flotation, the drug outlet of the 2# dosing device is also connected to the water inlet of the electrolytic flotation, the water outlet of the electrolytic flotation is connected to the water inlet of the secondary sedimentation tank through the secondary reaction tank, the drug outlet of the 3# dosing device is connected to the drug inlet of the secondary reaction tank, the water outlet of the secondary sedimentation tank is connected to the water inlet of the 1# clean water tank, the water outlet of the 1# clean water tank is connected to the 1# clean water tank through the 2# dosing device. The 1# clean water pump is connected to the water inlet of the oil removal membrane device, the water outlet of the oil removal membrane device is connected to the water inlet of the 2# clean water tank, the water outlet of the 2# clean water tank is connected to the water inlet of the material separation membrane device through the 2# clean water pump, the drug outlet of the 4# dosing device is also connected to the water inlet of the material separation membrane device, the water outlet of the material separation membrane device is connected to the water inlet of the 3# clean water tank, the water outlet of the 3# clean water tank is connected to the water inlet of the two-stage nanofiltration system through the 3# clean water pump, the drug outlet of the 5# dosing device is also connected to the water inlet of the two-stage nanofiltration system, the water outlet of the two-stage nanofiltration system is connected to the 1# water inlet of the nanofiltration water production tank, the water outlet of the nanofiltration water production tank is connected to the water inlet of the ultra-high pressure reverse osmosis device through the reverse osmosis booster pump, and the concentrated water outlet of the ultra-high pressure reverse osmosis device is connected to the reverse osmosis concentrated water outlet. The water inlet of the reverse osmosis concentrated water tank is connected to the water inlet of the bipolar membrane device through a bipolar membrane booster pump, the water outlet of the bipolar membrane device is connected to the 2# water inlet of the nanofiltration water production tank, the acid outlet of the bipolar membrane device is connected to the acid inlet of the dilute acid tank, the acid outlet of the dilute acid tank delivers dilute hydrochloric acid through the dilute acid pump, the alkali outlet of the bipolar membrane device is connected to the alkali inlet of the dilute alkali tank, and the alkali outlet of the dilute alkali tank delivers dilute sodium hydroxide through the dilute alkali pump; the mud outlet of the primary sedimentation tank is connected to the 1# mud inlet of the mud slag box, the slag outlet of the electrolytic flotation and the mud outlet of the secondary sedimentation tank are connected to the 2# mud inlet of the mud slag box, the mud outlet of the mud slag box is connected to the mud inlet of the plate and frame filter press through a mud slag pump, the water outlet of the plate and frame filter press is also connected to the water inlet of the electrolytic flotation, and the mud outlet of the plate and frame filter press delivers mud cake;The oil outlet of the oil removal membrane device is connected to the oil inlet of the concentrated oil tank, and the oil outlet of the concentrated oil tank is sent out for waste oil recovery through the concentrated oil pump; the concentrated water outlet of the material separation membrane device is connected to the 1# water inlet of the wastewater recovery tank, the concentrated water outlet of the two-stage nanofiltration system is connected to the 2# water inlet of the wastewater recovery tank, and the water outlet of the wastewater recovery tank is connected to the 2# water inlet of the raw water tank through the wastewater recovery pump; the water outlet of the ultra-high pressure reverse osmosis device is connected to the water inlet of the reverse osmosis water production tank, and the water outlet of the reverse osmosis water production tank sends out recycled water through the reverse osmosis water production pump. ;

[0007] Furthermore, the 1# dosing device includes a dosing box for lime, soda ash, polyferric sulfate, polyacrylamide, powdered carbon and a 1# metering pump;

[0008] The 2# dosing device includes a hydrochloric acid dosing box and a 2# metering pump;

[0009] The 3# dosing device includes a dosing box for the COD collector and a 3# metering pump;

[0010] The 4# dosing device includes a dosing box for the reducing agent and a 4# metering pump;

[0011] The 5# dosing device comprises a dosing box for scale inhibitor and non-oxidizing bactericide and a 5# metering pump.

[0012] A method for processing a tanning main soaking water resource treatment device, comprising the following steps:

[0013] 1) The main tanning water is passed through the primary reaction tank and the primary sedimentation tank in sequence, and the hardness, sulfate and COD in the water are reduced by adding chemicals, and then the pH value is adjusted back to 6-8 by adding acid;

[0014] 2) COD is reduced by adding COD collector through electrolytic flotation, secondary reaction tank and secondary sedimentation tank in sequence;

[0015] 3) Recover waste oil through oil film removal device;

[0016] 4) Separate and reduce COD through material separation membrane device;

[0017] 5) Through a two-stage nanofiltration system, COD is further separated and reduced, and divalent salts are removed;

[0018] 6) Produce recycled water through an ultra-high pressure reverse osmosis device and concentrate the monovalent salt to TDS ≥ 100,000 mg / L;

[0019] 7) The dilute acid and dilute alkali with a concentration of 2 mol / L are separated by a bipolar membrane device.

[0020] Furthermore, the step 1) sequentially passes through a primary reaction tank and a primary sedimentation tank, and for the main tanning water with a pH value of 8-10, a COD of 10000-20000 mg / L, an NH3-N of 200-500 mg / L, and a TDS of 20000-30000 mg / L, the water quality and quantity are first adjusted and improved using a raw water tank and a raw water pump, and the calcium carbonate in the main tanning water is reacted and precipitated with saturated calcium sulfate by adding lime, soda ash, polyferric sulfate, polyacrylamide, and powdered carbon, so that the effluent hardness is ≤0.5 mmol / L, the sulfate radical is ≤1800 mg / L, and the COD is 1500-3000 mg / L, and then the pH value is adjusted back to 6-8 by adding hydrochloric acid.

[0021] Furthermore, in step 2), the effluent from the primary sedimentation tank is subjected to electrolytic flotation, a secondary reaction tank and a secondary sedimentation tank in sequence, and the COD is reduced by adding a COD collector, and the effluent COD is reduced from 1500-3000 mg / L to 500-1000 mg / L, and the NH3-N is reduced from 200-500 mg / L to 20-50 mg / L by using an electrolytic flotation device, a secondary reaction tank and a secondary sedimentation tank.

[0022] Furthermore, in step 3), the effluent from the secondary sedimentation tank is first stored and lifted using the 1# clean water tank and the 1# clean water pump through the oil removal film device, and then the oil content of the effluent is reduced to ≤100 mg / L using the oil removal film device, and the waste oil is collected and transported for post-processing and reuse.

[0023] Furthermore, in step 4), the effluent from the oil removal membrane is first stored and lifted by the 2# clean water tank and the 2# clean water pump through the material separation membrane device, and then the COD is separated and recovered by the material separation membrane device, and returned to the front-end for treatment, so as to reduce the effluent COD to 150-300 mg / L, and at the same time, the material separation membrane is protected by adding a reducing agent.

[0024] Furthermore, in step 5), the effluent from the material separation membrane is first stored and pressurized using a 2# clean water tank and a 2# clean water pump through a two-stage nanofiltration system, and then the two-stage nanofiltration system is used to further separate and reduce COD, remove divalent salts, effectively concentrate COD and divalent salts, and return to the front-end for treatment, so that the effluent COD is ≤30 mg / L and the divalent salts are ≤20 mg / L. At the same time, the two-stage NF membrane is protected by adding antiscalants and non-oxidizing bactericides.

[0025] Furthermore, in step 6), the water effluent from the nanofiltration membrane is first stored and pressurized using a nanofiltration water production tank and a reverse osmosis booster pump through an ultra-high pressure reverse osmosis membrane, and then the monovalent salt of the concentrated water is concentrated to a TDS of ≥ 100,000 mg / L using an ultra-high pressure reverse osmosis device, and recycled water with a TDS of ≤ 700 mg / L is produced, thereby effectively recovering the water resources in the main tanning water.

[0026] Furthermore, in step 7), the ultra-high pressure reverse osmosis effluent is first stored and pressurized using the RO concentrated water circulation and bipolar membrane booster pump, and then the bipolar membrane device is used to separate the dilute acid and the dilute alkali, and hydrochloric acid and sodium hydroxide with a concentration of 2 mol / L are produced respectively.

[0027] The invention has the advantages that the invention relates to a resource-based treatment device and a treatment method for the main soaking water of leather making. Aiming at the characteristics of the main soaking water of leather making having large water volume, high pollutant concentration, complex composition, high suspended solids and high salt content, the first-level reaction tank and the first-level sedimentation tank are used to reduce the hardness, sulfate radical and COD of the main soaking water; then, electrolytic flotation, a secondary reaction tank and a secondary sedimentation tank, an oil removal membrane, a material separation membrane and a two-stage NF membrane are used in sequence to recover the waste oil, separate and concentrate the COD and divalent salt, and return them to the front-end for treatment; then, an ultra-high pressure RO membrane is used to produce recycled water with TDS≤700mg / L, and the sodium chloride is concentrated to ≥100000mg / L; finally, a bipolar membrane is used to produce dilute acid and dilute alkali, so as to achieve the purpose of resource-based treatment of leather making wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Attached Figure 1 Schematic diagram of the overall structure of the leather main soaking water resource treatment device.

[0029] In the attached figure, MIW means main immersion water, RWT means raw water tank, RWP means raw water pump, RWT / RWP means raw water tank and raw water pump, RT1 means primary reaction tank, ST1 means primary sedimentation tank, RT1 / ST1 means primary reaction tank and primary sedimentation tank, EF means electrolytic flotation, RT2 means secondary reaction tank, ST2 means secondary sedimentation tank, EF / RT2 / ST2 means electrolytic flotation, secondary reaction tank and secondary sedimentation tank, CWT1 means 1# clean water tank, CWP1 means 1# clean water pump, CWT1 / CWP1 means 1# clean water tank and 1# clean water pump, DOMS means oil removal film device, CWT2 means 2# clean water tank, CWP2 means 2# clean water pump, CWT2 / CWP2 means 2# clean water tank and 2# clean water pump, MSMS means material separation membrane device, CWT3 means 3# clean water tank, CWP3 means 3# clean water pump, CWT3 / CWP3 means 3# clean water tank and 3# clean water pump, 2NFS means two-stage nanofiltration device, NFPWT means nanofiltration water production tank, ROP means reverse osmosis booster pump, NFPWT / ROP means nanofiltration water production tank and reverse osmosis booster pump, UHPROS means ultra-high pressure reverse osmosis device, ROCWT means reverse osmosis concentrated water tank, BPEDP means bipolar Membrane booster pump, ROCWT / BPEDP means reverse osmosis concentrated water tank and bipolar membrane booster pump, BPEDS means bipolar membrane device, DAT means dilute acid tank, DAP means dilute acid pump, DAT / DAP means dilute acid tank and dilute acid pump, DHCl means dilute hydrochloric acid, DALT means dilute alkali tank, DALP means dilute alkali pump, DALT / DALP means dilute alkali tank and dilute alkali pump, DNaOH means dilute sodium hydroxide, SRT means sludge tank, SRP means sludge pump, BF means plate and frame filter press, SRT / SRP / BF means sludge tank, sludge pump and plate and frame filter press, SC means mud cake, COT means concentrated oil tank, COP stands for concentrated oil pump, COT / COP stands for concentrated oil tank and concentrated oil pump, WO stands for waste oil, DS1 stands for 1# dosing device, DS2 stands for 2# dosing device, DS3 stands for 3# dosing device, DS4 stands for 4# dosing device, DS5 stands for 5# dosing device, WWRT stands for wastewater recovery tank, WWRP stands for wastewater recovery pump, WWRT / WWRP stands for wastewater recovery tank and wastewater recovery pump, ROPWT stands for reverse osmosis water tank, ROPWP stands for reverse osmosis water pump, ROPWT / ROPWP stands for reverse osmosis water tank and reverse osmosis water pump, RCW stands for recycled water. DETAILED DESCRIPTION

[0030] Example 1

[0031] As attached Figure 1As shown, a tanning main soaking water resource treatment device, the structure of which includes a raw water tank RWT, a raw water pump RWP, a primary reaction tank RT1, a primary sedimentation tank ST1, an electrolytic flotation EF, a secondary reaction tank RT2, a secondary sedimentation tank ST2, a 1# clean water tank CWT1, a 1# clean water pump CWP1, an oil removal membrane device DOMS, a 2# clean water tank CWT2, a 2# clean water pump CWP2, a material separation membrane device MSMS, a 3# clean water tank CWT3, a 3# clean water pump CWP3, a two-stage nanofiltration system 2NFS, a nanofiltration water production tank NFPWT, a reverse osmosis booster pump ROP, and an ultra-high pressure reverse osmosis device U HPROS, reverse osmosis concentrated water tank ROCWT, bipolar membrane booster pump BPEDP, bipolar membrane device BPEDS, dilute acid tank DAT, dilute acid pump DAP, dilute alkali tank DALT / , dilute alkali pump DALP, sludge tank SRT, sludge pump SRP, plate and frame filter press BF, concentrated oil tank COT, concentrated oil pump COP, 1# dosing device DS1, 2# dosing device DS2, 3# dosing device DS3, 4# dosing device DS4, 5# dosing device DS5, wastewater recovery tank WWRT, wastewater recovery pump WWRP, reverse osmosis produced water tank ROPWT and reverse osmosis produced water pump ROPWP;The main immersion water MIW is connected to the 1# water inlet of the raw water tank RWT, the water outlet of the raw water tank RWT is connected to the water inlet of the primary reaction tank RT1 through the raw water pump RWP, the drug outlet of the 1# dosing device DS1 is connected to the drug inlet of the primary reaction tank RT1, the water outlet of the primary reaction tank RT1 is connected to the water inlet of the primary sedimentation tank ST1, the water outlet of the primary sedimentation tank ST1 is connected to the water inlet of the electrolytic flotation EF, the drug outlet of the 2# dosing device DS2 is also connected to the water inlet of the electrolytic flotation EF, the water outlet of the electrolytic flotation EF is connected to the water inlet of the secondary sedimentation tank ST2 through the secondary reaction tank RT2, the drug outlet of the 3# dosing device DS3 is connected to the drug inlet of the secondary reaction tank RT2, and the water outlet of the secondary sedimentation tank ST2 is connected to the water inlet of the electrolytic flotation EF. Connect to the water inlet of 1# clean water tank CWT1, the water outlet of 1# clean water tank CWT1 is connected to the water inlet of oil removal membrane device DOMS through 1# clean water pump CWP1, the water outlet of oil removal membrane device DOMS is connected to the water inlet of 2# clean water tank CWT2, the water outlet of 2# clean water tank CWT2 is connected to the water inlet of material separation membrane device MSMS through 2# clean water pump CWP2, the drug outlet of 4# dosing device DS4 is also connected to the water inlet of material separation membrane device MSMS, the water outlet of material separation membrane device MSMS is connected to the water inlet of 3# clean water tank CWT3, the water outlet of 3# clean water tank CWT3 is connected to the water inlet of two-stage nanofiltration system 2NFS through 3# clean water pump CWP3, 5# dosing device DS5 The drug outlet is also connected to the water inlet of the two-stage nanofiltration system 2NFS, the water outlet of the two-stage nanofiltration system 2NFS is connected to the 1# water inlet of the nanofiltration water production tank NFPWT, the water outlet of the nanofiltration water production tank NFPWT is connected to the water inlet of the ultra-high pressure reverse osmosis device UHPROS through the reverse osmosis booster pump ROP, the concentrated water outlet of the ultra-high pressure reverse osmosis device UHPROS is connected to the water inlet of the reverse osmosis concentrated water tank ROCWT, the water outlet of the reverse osmosis concentrated water tank ROCWT is connected to the water inlet of the bipolar membrane device BPEDS through the bipolar membrane booster pump BPEDP, the water outlet of the bipolar membrane device BPEDS is connected to the 2# water inlet of the nanofiltration water production tank NFPWT, and the acid outlet of the bipolar membrane device BPEDS is connected to the dilute acid tank DAT Acid inlet, acid outlet of dilute acid tank DAT delivers dilute hydrochloric acid DHCl through dilute acid pump DAP, alkali outlet of bipolar membrane device BPEDS is connected to alkali inlet of dilute alkali tank DALT, alkali outlet of dilute alkali tank DALT delivers dilute sodium hydroxide DNaOH through dilute alkali pump DALP; mud outlet of primary sedimentation tank ST1 is connected to 1# mud inlet of mud slag tank SRT, slag outlet of electrolytic flotation EF and mud outlet of secondary sedimentation tank ST2 are connected to 2# mud inlet of mud slag tank SRT, mud outlet of mud slag tank SRT is connected to mud inlet of plate and frame filter press BF through mud slag pump SRP, water outlet of plate and frame filter press BF is also connected to water inlet of electrolytic flotation EF, mud outlet of plate and frame filter press BF delivers mud cake SC (for external transportation);The oil outlet of the oil removal membrane device DOMS is connected to the oil inlet of the concentrated oil tank COT, and the oil outlet of the concentrated oil tank COT sends out the waste oil WO (recycling treatment) through the concentrated oil pump COP; the concentrated water outlet of the material separation membrane device MSMS is connected to the 1# water inlet of the wastewater recovery tank WWRT, the concentrated water outlet of the two-stage nanofiltration system 2NFS is connected to the 2# water inlet of the wastewater recovery tank WWRT, and the water outlet of the wastewater recovery tank WWRT is connected to the 2# water inlet of the raw water tank RWT through the wastewater recovery pump WWRP; the water outlet of the ultra-high pressure reverse osmosis device UHPROS is connected to the water inlet of the reverse osmosis water production tank ROPWT, and the water outlet of the reverse osmosis water production tank ROPWT sends out the recycled water RCW through the reverse osmosis water production pump ROPWP. ;

[0032] The 1# dosing device DS1 includes dosing boxes for lime, soda ash, PFS, PAM, powdered carbon and a 1# metering pump.

[0033] The 2# dosing device DS2 includes a hydrochloric acid dosing tank and a 2# metering pump.

[0034] The 3# dosing device DS3 includes a dosing box for COD collector and a 3# metering pump.

[0035] The 4# dosing device DS4 includes a dosing tank for the reducing agent and a 4# metering pump.

[0036] The 5# dosing device DS5 includes a dosing box for scale inhibitor and non-oxidizing bactericide and a 5# metering pump.

[0037] The treatment method of the tanning main soaking water resource treatment device comprises the following steps:

[0038] 1) The main tanning water is passed through the primary reaction tank and the primary sedimentation tank in sequence, and the hardness, sulfate and COD in the water are reduced by adding chemicals, and then the pH value is adjusted back to 6-8 by adding acid;

[0039] 2) COD is reduced by adding COD collector through electrolytic flotation EF, secondary reaction tank RT2 and secondary sedimentation tank ST2 in sequence;

[0040] 3) Recycle waste oil through degreasing film device DOMS;

[0041] 4) Separate and reduce COD through material separation membrane device MSMS;

[0042] 5) Through the two-stage nanofiltration device 2NFS, COD is further separated and reduced, and divalent salts are removed;

[0043] 6) Use the ultra-high pressure reverse osmosis device UFPROS to produce recycled water and concentrate the monovalent salt to TDS ≥ 100,000 mg / L;

[0044] 7) The dilute acid and dilute alkali with a concentration of 2 mol / L are separated by a bipolar membrane device BPEDS.

[0045] Step 1) sequentially passes through the primary reaction tank RT1 and the primary sedimentation tank ST1, specifically for the main tanning water with a pH value of 8-10, a COD of 10000-20000 mg / L, an NH3-N of 200-500 mg / L, and a TDS of 20000-30000 mg / L. First, the raw water tank RWT and the raw water pump RWP are used to adjust and improve the water quality and quantity, and by adding lime, soda ash, PFS (polyferric sulfate), PAM (polyacrylamide), and powdered carbon, the calcium carbonate in the main immersion water is reacted and precipitated with saturated calcium sulfate, so that the effluent hardness is ≤0.5 mmol / L, the sulfate radical is ≤1800 mg / L, and the COD is 1500-3000 mg / L, and then the pH value is adjusted back to 6-8 by adding hydrochloric acid.

[0046] Step 2) sequentially passes through electrolytic flotation EF, secondary reaction tank RT2 and secondary sedimentation tank ST2, specifically for the effluent of the primary sedimentation tank ST1, COD is reduced by adding COD collector, and electrolytic flotation EF, secondary reaction tank RT2 and secondary sedimentation tank ST2 are used to reduce the effluent COD from 1500-3000 mg / L to 500-1000 mg / L, and NH3-N from 200-500 mg / L to 20-50 mg / L.

[0047] Step 3) Through the oil removal membrane device DOMS, specifically for the effluent from the secondary sedimentation tank ST2, first use the 1# clean water tank CWT1 and 1# clean water pump CWP1 to store and lift, and then use the oil removal membrane device DOMS to reduce the effluent oil content to ≤100mg / L, collect the waste oil, and transport it for post-treatment and reuse.

[0048] Step 4) Through the material separation membrane device MSMS, specifically for the effluent of the oil removal membrane device DOMS, first use the 2# clean water tank CWT2 and the 2# clean water pump CWP2 to store and lift, and then use the material separation membrane device MSMS to separate and recover COD, return to the front-end treatment, reduce the effluent COD to 150-300 mg / L, and at the same time protect the material separation membrane by adding a reducing agent.

[0049] Step 5) Through the two-stage nanofiltration membrane, specifically for the effluent from the material separation membrane, first use the 2# clean water tank and 2# clean water pump for storage and pressurization, and then use the two-stage nanofiltration system to further separate and reduce COD, remove divalent salts, effectively concentrate COD and divalent salts (sodium sulfate), and return to the front-end treatment, so that the effluent COD ≤ 30 mg / L, divalent salt ≤ 20 mg / L, and at the same time protect the two-stage NF membrane by adding antiscalant and non-oxidizing bactericide.

[0050] Step 6) Through the ultra-high pressure reverse osmosis device UFPROS, specifically for the nanofiltration membrane effluent, first use the nanofiltration water production tank and RO booster pump for storage and pressurization, and then use the ultra-high pressure reverse osmosis device to concentrate the monovalent salt (sodium chloride) of the concentrated water to TDS ≥ 100000 mg / L, and produce recycled water with TDS ≤ 700 mg / L, effectively recovering the water resources in the main tanning water.

[0051] Step 7) Through the bipolar membrane device BPEDS, specifically for the ultra-high pressure reverse osmosis effluent, the RO concentrated water is firstly circulated and pressurized by the bipolar membrane booster pump BPED, and then the dilute acid and dilute alkali are separated by the bipolar membrane device BPEDS, and HCl (hydrochloric acid) and NaOH (sodium hydroxide) with a concentration of 2 mol / L are respectively produced, thereby effectively recovering the salt resources in the main tanning water, achieving the purpose of resource treatment of tanning wastewater and producing recycled water and dilute acid and alkali.

[0052] Example 2

[0053] This embodiment is the second embodiment of the present invention. This embodiment is different from the first embodiment in that it provides a verification test of a tanning main soaking water resource treatment device and a treatment method, and verifies and explains the technical effects used in this method.

[0054] A new material company is located in the local leather industry development zone, covering an area of ​​200 mu, with a total investment of 200 million yuan, forming an annual production capacity of 1.5 million cowhide automobile leathers; in the leather production process, the preparation section, tanning section, and dyeing and finishing section will generate a large amount of production wastewater; this embodiment mainly targets the high-salt and heavily polluted characteristics of the main soaking water in the preparation section, and utilizes the resource-based treatment technology of the main soaking water in leather making to conduct pilot verification, effectively recovering the water and salt resources in the wastewater.

[0055] 1. Design the influent water quality, water volume and products

[0056] The water quality of the main tanning water is designed as follows: Unit: g / L (excluding pH)

[0057] Element TDS COD <![CDATA[NH3-N]]> Oil pH content 22300 19680 385 190 8.5

[0058] The designed water volume for the main immersion of tanning is 24T / D (1T / H).

[0059] The amount of recycled water produced is 16.6T / D (0.69T / H), and TDS≤700mg / L.

[0060] The output is 2 mol / L (80 g / L) of hydrochloric acid 2.23 T / D (0.093 T / H) and 2 mol / L (73 g / L) of sodium hydroxide 1.87 T / D (0.078 T / H).

[0061] 2. Pilot equipment

[0062] The pilot equipment for resource treatment of the main tanning water is as follows:

[0063]

[0064]

[0065]

[0066] 3. Pilot test results

[0067] First of all, considering that the pilot system for resource treatment of the main tanning water is relatively small, the amount of added chemicals is difficult to control, and the dilution degree of some added chemicals is greater than the project scale.

[0068] First, the main tanning water has a Q of 24T / D (1T / H), TDS of 22300mg / L, and COD of 19680mg / L. It enters the raw water tank for water quality and quantity adjustment, and is combined with the subsequently recovered material separation membrane concentrate and second-level NF concentrate, whose Q is 3.8T / D (0.158T / H). The total Q is 27.8T / D (1.158T / H), and is lifted into the primary reaction tank by the raw water pump.

[0069] By adding Ca(OH)2 with a Q of 50 L / H and a concentration of 3%, Na2CO3 with a Q of 19 L / H and a concentration of 10%, PFS with a Q of 11.7 L / H and a concentration of 5%, PAM with a Q of 5.8 L / H and a concentration of 0.1%, and powdered carbon with a Q of 7.8 L / H and a concentration of 3%, respectively, after reacting in the primary reaction box and precipitating in the primary precipitator, the COD concentration of the effluent was reduced to 2952 mg / L and SO4 2- The concentration dropped to 1451 mg / L; the pH value of the effluent was adjusted back to 70.5 by adding HCl with a Q of 1.7 L / H and a concentration of 5%, and then flowed into the electrolytic flotation device.

[0070] After electrolytic flotation treatment, it enters the secondary reaction tank, and at the same time, a COD collector with a Q of 3.9L / H and a concentration of 3% is added. After passing through the secondary reaction tank and the secondary sedimentation tank, the effluent Q is 25.86T / D (1.08T / H), COD is reduced to 984mg / L, and NH3-N is reduced to 38mg / L, and enters the clean water tank 1; here, the sludge from the primary sedimentation tank and the secondary sedimentation tank is pumped into the sludge tank through two sludge pumps, and after plate and frame filtration, a mud cake with a Q of 2.21T / D (0.092T / H) and a water content of 70% is discharged.

[0071] The secondary sedimentation effluent is pressurized by the 1# clean water pump and enters the oil removal membrane device. The waste oil with a Q of 1.29T / D (0.054T / H) is recovered by ceramic membrane separation and sent to the concentrated oil tank. The effluent Q is 24.57T / D (1.02T / H), TDS is 22300mg / L, COD is 984mg / L, and oil content is ≤100mg / L, and enters the 2# clean water tank.

[0072] The outlet water of the oil removal membrane device is pressurized by the 2# clean water pump and enters the material separation membrane device. The material separation membrane is protected by adding a reducing agent with a Q of 0.5L / H and a concentration of 1%. The material separation membrane is used to separate and recover organic matter. The recovery rate of the material separation membrane is 95%. The concentrated water Q of the material separation membrane is 1.23T / D (0.051T / H), which is returned to the front-end for treatment. The produced water Q of the material separation membrane is 23.34T / D (0.973T / H), TDS is 22300mg / L, COD is 295mg / L, and enters the clean water tank 3.

[0073] The material separation membrane is pressurized by the clean water pump 3 and enters the two-stage nanofiltration device. The two-stage NF membrane is protected by adding a scale inhibitor with a Q of 0.5L / H and a concentration of 1% and a non-oxidizing bactericide with a Q of 0.4L / H and a concentration of 0.5%. The NF membrane is used to separate and recover organic matter and divalent salts. The recovery rate of the two-stage NF membrane device is 89%. The concentrated water Q of the two-stage NF membrane is Q2.57T / D (0.107T / H), which is returned to the front-end for treatment. The water produced by the two-stage NF membrane is Q20.77T / D (0.865T / H), TDS is 21300mg / L, COD is 29mg / L, SO4 2- ≤20mg / L, enters the nanofiltration water production tank.

[0074] The NF produced water is pressurized by an ultra-high pressure reverse osmosis booster pump and enters the ultra-high pressure reverse osmosis device. The ultra-high pressure reverse osmosis device has a desalination rate of 97% and a recovery rate of 80%. The recycled water with a Q of 16.62T / D (0.693T / H) and a TDS of 639mg / L is produced and enters the ultra-high pressure reverse osmosis produced water tank; at the same time, the concentrated liquid (mainly NaCl) with a Q of 4.15T / D (0.173T / H) and a TDS of 103944mg / L is concentrated and enters the ultra-high pressure reverse osmosis concentrated water tank.

[0075] Finally, the RO concentrated water is pressurized by a bipolar membrane booster pump and enters the bipolar membrane device, which produces hydrochloric acid with a Q of 2.23T / D (0.093T / H) and a concentration of 2mol / L (80g / L), and sodium hydroxide with a Q of 1.87T / D (0.078T / H) and a concentration of 2mol / L (73g / L).

Claims

1. A tanning main soaking water resource treatment device, characterized in that Including raw water tank, raw water pump, primary reaction tank, primary sedimentation tank, electrolytic flotation, secondary reaction tank, secondary sedimentation tank, 1# clean water tank, 1# clean water pump, oil removal membrane device, 2# clean water tank, 2# clean water pump, material separation membrane device, 3# clean water tank, 3# clean water pump, two-stage nanofiltration system, nanofiltration water tank, reverse osmosis booster pump, ultra-high pressure reverse osmosis device, reverse osmosis concentrated water tank, bipolar membrane booster pump, bipolar membrane device, dilute acid tank, dilute acid pump, dilute alkali tank, dilute alkali pump, sludge tank, sludge pump, plate and frame filter press, concentrated oil tank, concentrated oil pump, 1# dosing device, 2# dosing device, 3# dosing device, 4# dosing device, 5# dosing device, wastewater recovery tank, wastewater recovery pump, reverse osmosis water tank and reverse osmosis water pump; the main immersion water tank is the main immersion water tank, which is the main immersion water tank of the 1# system. Connect to the 1# water inlet of the raw water tank, the water outlet of the raw water tank is connected to the water inlet of the primary reaction tank through the raw water pump, the outlet of the 1# dosing device is connected to the water inlet of the primary reaction tank, the water outlet of the primary reaction tank is connected to the water inlet of the primary sedimentation tank, the water outlet of the primary sedimentation tank is connected to the water inlet of the electrolytic flotation, the outlet of the 2# dosing device is also connected to the water inlet of the electrolytic flotation, the water outlet of the electrolytic flotation is connected to the water inlet of the secondary sedimentation tank through the secondary reaction tank, the outlet of the 3# dosing device is connected to the water inlet of the secondary reaction tank, the water outlet of the secondary sedimentation tank is connected to the water inlet of the 1# clean water tank, the water outlet of the 1# clean water tank is connected to the water inlet of the oil removal membrane device through the 1# clean water pump, the water outlet of the oil removal membrane device is connected to the water inlet of the 2# clean water tank, and the 2# clean water tank The water outlet is connected to the water inlet of the material separation membrane device through the 2# clean water pump, the drug outlet of the 4# dosing device is also connected to the water inlet of the material separation membrane device, the water production port of the material separation membrane device is connected to the water inlet of the 3# clean water tank, the water outlet of the 3# clean water tank is connected to the water inlet of the two-stage nanofiltration system through the 3# clean water pump, the drug outlet of the 5# dosing device is also connected to the water inlet of the two-stage nanofiltration system, the water production port of the two-stage nanofiltration system is connected to the 1# water inlet of the nanofiltration water production tank, the water outlet of the nanofiltration water production tank is connected to the water inlet of the ultra-high pressure reverse osmosis device through the reverse osmosis booster pump, the concentrated water outlet of the ultra-high pressure reverse osmosis device is connected to the water inlet of the reverse osmosis concentrated water tank, the water outlet of the reverse osmosis concentrated water tank is connected to the water inlet of the bipolar membrane device through the bipolar membrane booster pump, and the outlet of the bipolar membrane device The water inlet is connected to the 2# water inlet of the nanofiltration water production tank, the acid outlet of the bipolar membrane device is connected to the acid inlet of the dilute acid tank, the acid outlet of the dilute acid tank delivers dilute hydrochloric acid through the dilute acid pump, the alkali outlet of the bipolar membrane device is connected to the alkali inlet of the dilute alkali tank, and the alkali outlet of the dilute alkali tank delivers dilute sodium hydroxide through the dilute alkali pump; the mud outlet of the primary sedimentation tank is connected to the 1# mud inlet of the mud slag box, the slag outlet of the electrolytic flotation and the mud outlet of the secondary sedimentation tank are connected to the 2# mud inlet of the mud slag box, the mud outlet of the mud slag box is connected to the mud inlet of the plate and frame filter press through the mud slag pump, the water outlet of the plate and frame filter press is also connected to the water inlet of the electrolytic flotation, and the mud outlet of the plate and frame filter press delivers mud cake; the oil outlet of the oil removal film device is connected to the oil inlet of the concentrated oil tank, and the oil outlet of the concentrated oil tank delivers waste oil for recovery and treatment through the concentrated oil pump;The concentrated water outlet of the material separation membrane device is connected to the 1# water inlet of the wastewater recovery tank, the concentrated water outlet of the two-stage nanofiltration system is connected to the 2# water inlet of the wastewater recovery tank, and the water outlet of the wastewater recovery tank is connected to the 2# water inlet of the raw water tank through the wastewater recovery pump; the water outlet of the ultra-high pressure reverse osmosis device is connected to the water inlet of the reverse osmosis water production tank, and the water outlet of the reverse osmosis water production tank sends out the recycled water through the reverse osmosis water production pump. ; 2. The tanning main soaking water resource treatment device according to claim 1 is characterized in that: The 1# dosing device includes a dosing box for lime, soda ash, polyferric sulfate, polyacrylamide, powdered carbon and a 1# metering pump; The 2# dosing device includes a hydrochloric acid dosing box and a 2# metering pump; The 3# dosing device includes a dosing box for the COD collector and a 3# metering pump; The 4# dosing device includes a dosing box for the reducing agent and a 4# metering pump; The 5# dosing device comprises a dosing box for scale inhibitor and non-oxidizing bactericide and a 5# metering pump.

3. The treatment method based on the tanning main soaking water resource treatment device according to claim 1 is characterized in that The steps include: 1) The main tanning water is passed through the primary reaction tank and the primary sedimentation tank in sequence, and the hardness, sulfate and COD in the water are reduced by adding chemicals, and then the pH value is adjusted back to 6-8 by adding acid; 2) COD is reduced by adding COD collector through electrolytic flotation, secondary reaction tank and secondary sedimentation tank in sequence; 3) Recover waste oil through oil film removal device; 4) Separate and reduce COD through material separation membrane device; 5) Through the two-stage nanofiltration system, COD is further separated and reduced, and divalent salts are removed; 6) Through the ultra-high pressure reverse osmosis device, the recycled water is produced and the monovalent salt is concentrated to TDS ≥ 100,000 mg / L; 7) Separate the dilute acid and dilute alkali with a concentration of 2 mol / L through a bipolar membrane device.

4. The method for treating the main tanning water resource treatment device according to claim 3, characterized in that In the step 1), the primary reaction tank and the primary sedimentation tank are sequentially used to adjust and improve the water quality and quantity of the main tanning water with a pH value of 8-10, a COD of 10000-20000 mg / L, an NH3-N of 200-500 mg / L, and a TDS of 20000-30000 mg / L by using a raw water tank and a raw water pump, and then the calcium carbonate in the main tanning water is reacted and precipitated with saturated calcium sulfate by adding lime, soda ash, polyferric sulfate, polyacrylamide, and powdered carbon, so that the effluent hardness is ≤0.5 mmol / L, the sulfate radical is ≤1800 mg / L, and the COD is 1500-3000 mg / L, and then the pH value is adjusted back to 6-8 by adding hydrochloric acid.

5. The method for treating the main tanning water resource treatment device according to claim 3, characterized in that In the step 2), the effluent from the primary sedimentation tank is subjected to electrolytic flotation, a secondary reaction tank and a secondary sedimentation tank in sequence, and a COD collector is added to reduce the COD. The effluent COD is reduced from 1500-3000 mg / L to 500-1000 mg / L, and the NH3-N is reduced from 200-500 mg / L to 20-50 mg / L by using an electrolytic flotation device, a secondary reaction tank and a secondary sedimentation tank.

6. The method for treating the main tanning water resource treatment device according to claim 3, characterized in that In step 3), the effluent from the secondary sedimentation tank is first stored and lifted by the 1# clean water tank and the 1# clean water pump through the oil removal film device, and then the oil content of the effluent is reduced to ≤100 mg / L by the oil removal film device, and the waste oil is collected and transported for post-treatment and reuse.

7. The method for treating the main tanning water resource treatment device according to claim 3, characterized in that In step 4), the effluent from the oil removal membrane is first stored and lifted by the 2# clean water tank and the 2# clean water pump through the material separation membrane device, and then the COD is separated and recovered by the material separation membrane device and returned to the front-end for treatment, so as to reduce the effluent COD to 150-300 mg / L, and at the same time, the material separation membrane is protected by adding a reducing agent.

8. The method for treating the main tanning water resource treatment device according to claim 3, characterized in that In step 5), the effluent from the material separation membrane is first stored and pressurized using the 2# clean water tank and the 2# clean water pump through a two-stage nanofiltration system, and then the two-stage nanofiltration system is used to further separate and reduce COD, remove divalent salts, effectively concentrate COD and divalent salts, and return them to the front-end for treatment, so that the effluent COD is ≤30 mg / L and the divalent salts are ≤20 mg / L. At the same time, the two-stage NF membrane is protected by adding antiscalant and non-oxidizing bactericide.

9. The method for treating the main tanning water resource treatment device according to claim 3, characterized in that In step 6), the effluent from the nanofiltration membrane is first stored and pressurized using a nanofiltration water production tank and a reverse osmosis booster pump through an ultra-high pressure reverse osmosis membrane, and then the monovalent salt of the concentrated water is concentrated to a TDS of ≥ 100,000 mg / L using an ultra-high pressure reverse osmosis device, and recycled water with a TDS of ≤ 700 mg / L is produced, thereby effectively recovering the water resources in the main tanning water.

10. The method for treating the main tanning water resource treatment device according to claim 3, characterized in that In step 7), the ultra-high pressure reverse osmosis effluent is first stored and pressurized by circulating RO concentrated water with a bipolar membrane booster pump, and then separated into dilute acid and dilute alkali by a bipolar membrane device, producing hydrochloric acid and sodium hydroxide with a concentration of 2 mol / L, respectively.

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