Multi-index combined control treatment process and system for fluorine-containing wastewater generated in new energy industry

Abstract

The invention discloses a multi-index combined control treatment process and system for fluorine-containing wastewater generated in the new energy industry. The multi-index combined control treatment system comprises a first-stage fluorine removal subsystem, a second-stage fluorine removal subsystem, a third-stage water treatment subsystem, a fourth-stage water treatment subsystem and a drainage subsystem. The method has the advantages of simple process flow, small investment, small occupied area and low operation cost, the treated effluent can meet the multi-index up-to-standard discharge requirement, and the generated sludge can be recycled for preparing a coagulant, can also be used as a heavy metal flocculation adsorbent and can also be used as a raw material for manufacturing cement, so that waste can be turned into wealth, and high-value resource reutilization is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and in particular to a multi-index joint control treatment process and system for fluorine-containing wastewater generated in the new energy industry. Background Art

[0002] At present, the new energy industry uses chemical reagents such as hydrofluoric acid, hydrochloric acid, sulfuric acid, and nitric acid in the production process. Therefore, the main pollutants in the wastewater generated on the production line are fluoride, chloride, sulfate, nitrate, etc. The main characteristic pollutant is fluoride. Long-term drinking of water with a high fluoride content (>1.5mg / L) will cause chronic diseases such as dental fluorosis and fluorosis. my country's "Healthy Standards for Drinking Water" (GB 5749-2022) stipulates that the fluoride concentration in drinking water cannot be higher than 1mg / L. In addition, chloride and sulfate pollution has gradually attracted national attention due to its harm to the ecological environment and human health. The national standard "Farmland Irrigation Water Quality Standard" (GB 5084-2021) stipulates that the upper limit of chloride content in farmland irrigation is 350mg / L, "Surface Water Environmental Quality Standard" (GB 3838-2002) stipulates that the chloride concentration cannot be higher than 250mg / L, and the sulfate concentration cannot be higher than 250mg / L, "Groundwater Quality Standard" (GB / T14848-2017) stipulates that the chloride concentration cannot be higher than 350mg / L, and the sulfate concentration cannot be higher than 350mg / L, "Sewage Discharge into Urban Sewers Water Quality Standard" (GB / T 31962-2015) requires that the chloride concentration cannot be higher than 800mg / L, and the sulfate concentration cannot be higher than 600mg / L. As environmental protection policies in various places become more and more stringent, many provinces have added control over chloride and sulfate to the control indicators for wastewater discharged from the new energy industry.

[0003] However, the wastewater generated in the production process of the new energy industry is often treated by chemical precipitation and flocculation precipitation, that is, by adding chemical agents to the wastewater to form calcium fluoride precipitation, and then using the solid-liquid separation of the precipitate and the wastewater to achieve the purpose of purification. Commonly used precipitants include lime, calcium chloride, polyaluminium chloride (PAC), etc., and a variety of precipitants are used in combination, especially calcium salts with good water solubility (such as CaCl2) as a supplement to lime to treat the wastewater. After treatment, the fluoride concentration meets the national or local emission standards, but the chloride and sulfate concentrations are very high, far exceeding the corresponding emission standards. Therefore, it is imperative to explore new processes for wastewater purification in the new energy industry to achieve multi-index joint control, promote environmental protection, and further create a harmonious ecological environment. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a multi-index joint control treatment process and system for fluorine-containing wastewater generated in the new energy industry in view of the deficiencies in the above-mentioned prior art.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows: In the first aspect of the present invention, a multi-index joint control treatment system for fluorine-containing wastewater generated by the new energy industry is provided, comprising: a primary defluorination subsystem, a secondary defluorination subsystem, a tertiary water treatment subsystem, a quaternary water treatment subsystem and a drainage subsystem;

[0006] The primary defluorination subsystem comprises a comprehensive fluorine-containing wastewater regulating tank, a primary pH regulating reaction tank A, a primary pH regulating reaction tank B, a primary flocculation tank and a primary sedimentation tank connected in sequence;

[0007] The secondary defluorination subsystem comprises a secondary pH adjustment reaction tank, a secondary reaction tank, a secondary coagulation tank, a secondary flocculation tank and a secondary sedimentation tank connected in sequence;

[0008] The three-stage water treatment subsystem includes a three-stage reaction tank, a three-stage flocculation tank and a three-stage sedimentation tank connected in sequence;

[0009] The four-stage water treatment subsystem includes a four-stage reaction tank, a four-stage flocculation tank and a four-stage sedimentation tank connected in sequence;

[0010] The effluent from the primary sedimentation tank enters the secondary pH adjustment reaction tank, the effluent from the secondary sedimentation tank enters the tertiary reaction tank, the effluent from the tertiary sedimentation tank enters the quaternary reaction tank, and the effluent from the quaternary sedimentation tank enters the drainage subsystem.

[0011] Preferably, the primary defluorination subsystem further comprises an acid-containing wastewater regulating tank and an alkali-containing wastewater regulating tank, and the effluents of the acid-containing wastewater regulating tank and the alkali-containing wastewater regulating tank both enter the comprehensive fluorine-containing wastewater regulating tank.

[0012] Preferably, the system further comprises a first sludge treatment subsystem and a second sludge treatment subsystem.

[0013] Preferably, the first sludge treatment subsystem comprises a first physicochemical sludge tank and a first filter press connected in sequence;

[0014] The sludge in the primary sedimentation tank and the secondary sedimentation tank both enter the first physicochemical sludge tank, and the filtrate from the first filter press returns to the primary pH adjustment reaction tank A.

[0015] Preferably, the second sludge treatment subsystem comprises a second physicochemical sludge tank and a second filter press connected in sequence;

[0016] The sludge from the tertiary sedimentation tank and the quaternary sedimentation tank all enter the second physicochemical sludge tank, and the filtrate from the second filter press returns to the tertiary reaction tank.

[0017] Preferably, the drainage subsystem comprises a fluorine-containing effluent pH adjustment tank, a fluorine-containing Parshall tank and a fluorine-containing discharge tank which are sequentially connected to the four-stage reaction tank.

[0018] The second aspect of the present invention provides a multi-index joint control treatment process for fluorine-containing wastewater generated in the new energy industry, which uses the system as described above to treat fluorine-containing wastewater, which includes acid-containing wastewater and alkali-containing wastewater.

[0019] Preferably, the multi-index joint control treatment process for fluorine-containing wastewater generated by the new energy industry comprises the following steps:

[0020] S1. The acid-containing wastewater and the alkali-containing wastewater are transported to the acid-containing wastewater regulating tank and the alkali-containing wastewater regulating tank respectively, and then the wastewater in the acid-containing wastewater regulating tank and the alkali-containing wastewater regulating tank is pumped into the comprehensive fluorine-containing wastewater regulating tank;

[0021] S2, pumping the comprehensive fluorine-containing wastewater in the comprehensive fluorine-containing wastewater regulating tank into the primary pH adjustment reaction tank A, adding lime water solution into the primary pH adjustment reaction tank A, and stirring, adjusting the pH value to 10-10.5, and the residence time is 5-30min;

[0022] The wastewater in the primary pH adjustment reaction tank A is pumped into the primary pH adjustment reaction tank B, sulfuric acid solution is added to the primary pH adjustment reaction tank B, and stirred to adjust the pH value to 8.5-9.0, and the residence time is 10-40min;

[0023] The wastewater in the primary pH adjustment reaction tank B is pumped into the primary flocculation tank, polyacrylamide is added to the primary flocculation tank, stirred and flocculated, and then enters the primary sedimentation tank for sedimentation. The sludge is pumped into the first physicochemical sludge tank, and the effluent enters the secondary pH adjustment reaction tank;

[0024] S3, add lime water solution to the secondary pH adjustment reaction tank, stir, adjust the pH value to 10, and the residence time is 2-10min;

[0025] The wastewater in the secondary pH adjustment reaction tank is pumped into the secondary reaction tank, and calcium chloride solution is added to the secondary reaction tank, and stirred to maintain the calcium-fluoride molar ratio in the secondary reaction tank system at 0.5-0.6, and the residence time is 10-40 minutes;

[0026] The wastewater in the secondary reaction tank is pumped into the secondary coagulation tank, and flocculants are added to the secondary coagulation tank with a retention time of 10-40 minutes;

[0027] The wastewater in the secondary coagulation tank is pumped into the secondary flocculation tank, polyacrylamide is added to the secondary flocculation tank, stirred and flocculated, and then enters the secondary sedimentation tank for sedimentation. The sludge is pumped into the first physicochemical sludge tank, and the effluent enters the tertiary reaction tank;

[0028] The sludge in the first physicochemical sludge tank is dehydrated by filtration and then outsourced for treatment, and the filtrate is returned to the primary pH adjustment reaction tank A;

[0029] S4, add lime water solution and sodium aluminate solution to the tertiary reaction tank to maintain the Ca 2 + :Al 3+ :SO4 2- The molar ratio is 2:0.7:1-3:1:1, and the residence time is 20-80min;

[0030] The wastewater in the tertiary reaction tank is pumped into the tertiary flocculation tank, polyacrylamide solution is added to the tertiary flocculation tank, stirred and flocculated, and then enters the tertiary sedimentation tank for sedimentation. The sludge is pumped into the second physicochemical sludge tank, and the effluent enters the quaternary reaction tank;

[0031] S5, add lime water solution and sodium aluminate solution to the fourth-stage reaction tank to maintain the Ca content in the third-stage reaction tank system. 2 + :Al 3+ :SO4 2- The molar ratio is 2:1:1 to 3:1.5:1, and the residence time is 20-80min;

[0032] The wastewater in the four-stage reaction tank is pumped into the four-stage flocculation tank, and the polyacrylamide solution is added to the four-stage flocculation tank, stirred and flocculated, and then enters the four-stage sedimentation tank for sedimentation. The sludge is pumped into the second physicochemical sludge tank, and the effluent enters the fluoride-containing effluent pH adjustment tank;

[0033] The sludge in the second physicochemical sludge tank is filtered and dehydrated by the second filter press, and the obtained dry sludge is used to prepare coagulant, heavy metal flocculation adsorbent or cement; the filtrate of the second filter press is returned to the tertiary reaction tank;

[0034] S6. Add boric acid to the fluorine-containing effluent pH adjustment pool to adjust the pH value to 6.5-9.5. The effluent from the fluorine-containing effluent pH adjustment pool passes through the fluorine-containing Parshall trough and the fluorine-containing discharge pool in turn before meeting the discharge standards.

[0035] Preferably, the flocculant in step S3 is at least one of polyaluminium chloride and polyaluminium sulfate.

[0036] Preferably, the multi-index joint control treatment process for fluorine-containing wastewater generated by the new energy industry comprises the following steps:

[0037] S1. The acid-containing wastewater and the alkali-containing wastewater are transported to the acid-containing wastewater regulating tank and the alkali-containing wastewater regulating tank respectively, and then the wastewater in the acid-containing wastewater regulating tank and the alkali-containing wastewater regulating tank is pumped into the comprehensive fluorine-containing wastewater regulating tank according to a certain flow ratio;

[0038] S2, the comprehensive fluorine-containing wastewater in the comprehensive fluorine-containing wastewater regulating tank is pumped into the primary pH adjustment reaction tank A, and a lime solution with a concentration of 10wt% to 30wt% is added to the primary pH adjustment reaction tank A, and stirred to adjust the pH value to 10 to 10.5, and the residence time is 15min;

[0039] The wastewater in the primary pH adjustment reaction tank A is pumped into the primary pH adjustment reaction tank B, and a 50wt% sulfuric acid solution is added to the primary pH adjustment reaction tank B, and stirred to adjust the pH value to 8.5-9.0, with a residence time of 20min;

[0040] The wastewater in the primary pH adjustment reaction tank B is pumped into the primary flocculation tank, and a polyacrylamide (PAM) solution with a concentration of 0.4wt% is added to the primary flocculation tank, and slowly stirred, so that the fine suspended particles in the wastewater flocculate to form a gel feather, and then enter the primary sedimentation tank for sedimentation. The suspended gel feather settles to form sludge, and the sludge enters the first physicochemical sludge tank through a pump, and the effluent enters the secondary pH adjustment reaction tank;

[0041] In this step, excess lime is first added, and the Ca in the lime solution 2+ With F - The reaction forms CaF2, and then sulfuric acid is added, and SO4 in the sulfuric acid solution 2- With excess Ca 2+ The reaction forms CaSO4. In the presence of CaSO4 in the system, the solubility of CaF2 in water can be further reduced due to the common ion effect. More than 95% of F in the wastewater - was removed.

[0042] S3, add 10wt% to 30wt% lime water solution into the secondary pH adjustment reaction tank, stir, adjust the pH value to 10, and the residence time is 5min;

[0043] The wastewater in the secondary pH adjustment reaction tank is pumped into the secondary reaction tank, and a 30wt% calcium chloride solution is added to the secondary reaction tank, and stirred to maintain the calcium-fluorine molar ratio in the secondary reaction tank system at 0.5-0.6, and the residence time is 30min;

[0044] The wastewater in the secondary reaction tank is pumped into the secondary coagulation tank, and a 10wt% polyaluminium chloride solution or a 10wt% polyaluminium sulfate solution is added to the secondary coagulation tank, the dosage is maintained at 1000-1500mg / L, and the residence time is 20min;

[0045] The wastewater in the secondary coagulation tank is pumped into the secondary flocculation tank, and a polyacrylamide (PAM) solution with a concentration of 0.4wt% is added to the secondary flocculation tank. The fine suspended particles in the wastewater are flocculated to form a gel feather, and then enter the secondary sedimentation tank for sedimentation. The suspended gel feather settles to form sludge, and the sludge is pumped into the first physicochemical sludge tank, and the effluent enters the tertiary reaction tank;

[0046] The sludge in the first physicochemical sludge tank is dehydrated by filtration and then outsourced for treatment, and the filtrate is returned to the primary pH adjustment reaction tank A;

[0047] In this step, lime solution and calcium chloride solution are added to form a common ion effect to promote Ca 2+ With F - The reaction forms CaF2, which is then combined with the "compressed double electric layer", "electrical neutralization", "adsorption" of the high-efficiency coagulant polyaluminium chloride or polyaluminium sulfate, and the "precipitation net capture" and "adsorption bridging" of the polymer flocculant PAM to generate CaF2 precipitate, further removing F in the wastewater. - .

[0048] S4, add 30wt% lime water solution and 30wt% sodium aluminate solution to the tertiary reaction tank to maintain the Ca content in the tertiary reaction tank system. 2+ :Al 3+ :SO4 2- The molar ratio is 2:0.7:1-3:1:1, and the residence time is 40min;

[0049] The wastewater in the tertiary reaction tank is pumped into the tertiary flocculation tank, and a polyacrylamide (PAM) solution with a concentration of 0.4wt% is added to the tertiary flocculation tank, and slowly stirred, so that the fine suspended particles in the wastewater flocculate to form gel feathers, and finally enter the tertiary sedimentation tank for sedimentation. The suspended gel feathers settle to form sludge, and the sludge is pumped into the second physicochemical sludge tank, and the effluent enters the quaternary reaction tank;

[0050] In this step, the main reactions that occur are as follows:

[0051] NaAlO2+2H2O=NaOH+Al(OH)3

[0052]

[0053] 4Ca(OH)2+2Al(OH)3+2Cl - =Ca4Al2Cl2(OH) 12 +2OH -

[0054] SO4 2- and Cl - The precipitate Ca6Al2(SO4)3(OH) 12、Ca4Al2Cl2(OH) 12 Form removal, due to Ca6Al2(SO4)3(OH) 12 than Ca4Al2Cl2(OH) 12 The solubility product constant is smaller, so SO4 2- Priority is given to removal.

[0055] S5, add 30wt% lime water solution and 30wt% sodium aluminate solution to the fourth-stage reaction tank to maintain the Ca content in the third-stage reaction tank system. 2+ :Al 3+ :SO4 2- The molar ratio is 2:1:1 to 3:1.5:1, and the residence time is 40min;

[0056] The wastewater in the fourth-stage reaction tank is pumped into the fourth-stage flocculation tank, and a polyacrylamide (PAM) solution with a concentration of 0.4wt% is added to the fourth-stage flocculation tank, and slowly stirred, so that the fine suspended particles in the wastewater flocculate to form a gel feather, and then enter the fourth-stage sedimentation tank for sedimentation. The suspended gel feather settles to form sludge, and the sludge is pumped into the second physicochemical sludge tank, and the effluent enters the fluorine-containing effluent pH adjustment tank;

[0057] In this step, the main reactions that occur are as follows:

[0058] NaAlO2+2H2O=NaOH+Al(OH)3

[0059]

[0060] 4Ca(OH)2+2Al(OH)3+2Cl - =Ca4Al2Cl2(OH) 12 +2OH -

[0061]

[0062] After the sludge in the second physicochemical sludge pool is filtered and dehydrated by the second filter press, the obtained dry sludge can be recycled for the preparation of coagulant, can also be used as a heavy metal flocculation adsorbent, and can also be used as a raw material for cement manufacturing, realizing high-value resource recycling and turning waste into treasure; the filtrate of the second filter press is returned to the tertiary reaction tank;

[0063] S6. Add boric acid to the fluorine-containing effluent pH adjustment tank to adjust the pH value to 6.5-9.5. The effluent from the fluorine-containing effluent pH adjustment tank passes through the fluorine-containing Parshall trough and the fluorine-containing discharge tank in sequence, and meets the emission requirements of relevant indicators in the "Battery Industry Pollutant Emission Standard" (GB30484-2013), "Water Quality Standard for Sewage Discharge into Urban Sewers" (GBT31962-2015) and "Sichuan Province Water Pollutant Emission Standard" before reaching the discharge standard.

[0064] The beneficial effects of the present invention are:

[0065] The present invention provides a multi-index joint control treatment system and treatment process for fluorine-containing wastewater generated in the new energy industry. The present invention has the advantages of simple process flow, small investment, small footprint and low operating cost. Not only can the effluent after treatment meet the multi-index emission requirements, but the generated sludge can be recycled for the preparation of coagulants, as a heavy metal flocculation adsorbent, and as a raw material for manufacturing cement, which can turn waste into treasure and realize high-value resource recycling. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 This is a flow chart of a multi-index combined control treatment process for fluorine-containing wastewater generated by the new energy industry of the present invention;

[0067] Figure 2 This is a flow chart of the conventional treatment process for fluorine-containing wastewater in the comparative example. DETAILED DESCRIPTION

[0068] The present invention is further described in detail below in conjunction with embodiments so that those skilled in the art can implement the invention with reference to the description.

[0069] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0070] The test methods used in the following examples are conventional methods unless otherwise specified. The materials and reagents used in the following examples are all commercially available unless otherwise specified. In the following examples, if no specific conditions are specified, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used, if the manufacturer is not specified, are all conventional products that can be purchased commercially.

[0071] Example 1

[0072] A multi-index joint control treatment system for fluorine-containing wastewater generated by the new energy industry, comprising: a primary defluorination subsystem, a secondary defluorination subsystem, a tertiary water treatment subsystem, a quaternary water treatment subsystem, a drainage subsystem, a first sludge treatment subsystem and a second sludge treatment subsystem;

[0073] The primary defluorination subsystem includes a comprehensive fluorine-containing wastewater regulating tank, a primary pH regulating reaction tank A, a primary pH regulating reaction tank B, a primary flocculation tank and a primary sedimentation tank connected in sequence;

[0074] The primary fluoride removal subsystem also includes an acid wastewater regulating tank and an alkali wastewater regulating tank. The effluents from the acid wastewater regulating tank and the alkali wastewater regulating tank all enter the comprehensive fluoride wastewater regulating tank.

[0075] The secondary defluorination subsystem includes a secondary pH adjustment reaction tank, a secondary reaction tank, a secondary coagulation tank, a secondary flocculation tank and a secondary sedimentation tank connected in sequence;

[0076] The tertiary water treatment subsystem includes a tertiary reaction tank, a tertiary flocculation tank and a tertiary sedimentation tank connected in sequence;

[0077] The four-stage water treatment subsystem includes a four-stage reaction tank, a four-stage flocculation tank and a four-stage sedimentation tank connected in sequence;

[0078] The effluent from the primary sedimentation tank enters the secondary pH adjustment reaction tank, the effluent from the secondary sedimentation tank enters the tertiary reaction tank, the effluent from the tertiary sedimentation tank enters the quaternary reaction tank, and the effluent from the quaternary sedimentation tank enters the drainage subsystem.

[0079] The first sludge treatment subsystem includes a first physicochemical sludge tank and a first filter press connected in sequence; the sludge from the primary sedimentation tank and the secondary sedimentation tank both enter the first physicochemical sludge tank, and the filtrate from the first filter press returns to the primary pH adjustment reaction tank A.

[0080] The second sludge treatment subsystem includes a second physicochemical sludge tank and a second filter press connected in sequence; the sludge from the tertiary sedimentation tank and the quaternary sedimentation tank all enter the second physicochemical sludge tank, and the filtrate from the second filter press returns to the tertiary reaction tank.

[0081] The drainage subsystem includes a fluorine-containing effluent pH adjustment tank, a fluorine-containing Parshall tank and a fluorine-containing discharge tank which are sequentially connected to the four-stage reaction tank.

[0082] Example 2

[0083] A multi-index joint control treatment process for fluorine-containing wastewater generated in the new energy industry, which uses the system of Example 1 to treat fluorine-containing wastewater, and the process includes the following steps:

[0084] S1. The acid-containing wastewater and the alkali-containing wastewater are transported to the acid-containing wastewater regulating tank and the alkali-containing wastewater regulating tank respectively, and then the wastewater in the acid-containing wastewater regulating tank and the alkali-containing wastewater regulating tank is pumped into the comprehensive fluorine-containing wastewater regulating tank;

[0085] Specifically, the fluorine-containing wastewater generated by a new energy industry includes concentrated acid wastewater, dilute acid wastewater, concentrated alkali wastewater, and dilute alkali wastewater. The water volume and water quality data of the comprehensive fluorine-containing wastewater after the four types of fluorine-containing wastewater are mixed at a certain flow rate ratio are as follows: water volume 5000m 3 / d, pH 1.04, fluoride concentration 4614.2 mg / L, chloride concentration 433.9 mg / L, sulfate concentration 102 mg / L, total nitrogen concentration 95 mg / L, TDS 4250 mg / L, conductivity 8.51 ms / cm.

[0086] S2, the comprehensive fluorine-containing wastewater in the comprehensive fluorine-containing wastewater regulating tank is discharged at a flow rate of 208.33m 3 / h pumped into the primary pH adjustment reaction tank A, and a 30wt% lime solution (flow rate 6.25m 3 / h) and stirred, adjusting the pH value to 10-10.5, and the residence time to 15min;

[0087] The wastewater in the primary pH adjustment reaction tank A is pumped into the primary pH adjustment reaction tank B, and a 50wt% sulfuric acid solution (flow rate 0.208m 3 / h) and stirred, adjusting the pH value to 8.5-9.0, and the residence time to 20min;

[0088] The wastewater in the primary pH adjustment reaction tank B is pumped into the primary flocculation tank, and a polyacrylamide solution with a concentration of 0.4wt% is added to the primary flocculation tank, and slowly stirred, so that the fine suspended particles in the wastewater flocculate to form gel feathers, and then enter the primary sedimentation tank for sedimentation. The suspended gel feathers are precipitated to form sludge, and the sludge is pumped into the first physicochemical sludge tank, and the effluent enters the secondary pH adjustment reaction tank;

[0089] The water quality data of the effluent from the primary sedimentation tank are: pH 9, fluoride concentration 159.7 mg / L, chloride concentration 413.3 mg / L, sulfate concentration 702 mg / L, and total nitrogen concentration 94 mg / L.

[0090] S3, add 30wt% lime water solution (flow rate 0.083m 3 / h) and stirred, the pH value was adjusted to 10, and the residence time was 5min;

[0091] The wastewater in the secondary pH adjustment reaction tank is pumped into the secondary reaction tank, and a 30wt% calcium chloride solution (flow rate 0.324m 3 / h) and stirred to maintain the calcium-fluorine molar ratio in the secondary reaction tank system at 0.5 and the residence time at 30min;

[0092] The wastewater in the secondary reaction tank is pumped into the secondary coagulation tank, and a 10wt% polyaluminium chloride solution (flow rate 0.208m 3 / h), residence time 20min;

[0093] The wastewater in the secondary coagulation tank is pumped into the secondary flocculation tank, and a polyacrylamide solution with a concentration of 0.4wt% is added to the secondary flocculation tank. The fine suspended particles in the wastewater are flocculated to form gel feathers, and then enter the secondary sedimentation tank for sedimentation. The suspended gel feathers are precipitated to form sludge. The sludge is pumped into the first physicochemical sludge tank, and the effluent enters the tertiary reaction tank;

[0094] The sludge in the first physicochemical sludge tank is dehydrated by filtration and then outsourced for treatment, and the filtrate is returned to the primary pH adjustment reaction tank A;

[0095] The water quality data of the effluent from the secondary sedimentation tank are: pH 6.84, fluoride concentration 5.05 mg / L, chloride concentration 1095.32 mg / L, sulfate concentration 693 mg / L, and total nitrogen concentration 94 mg / L.

[0096] S4, add 30wt% lime water solution and 30wt% sodium aluminate solution to the tertiary reaction tank to maintain the Ca content in the tertiary reaction tank system. 2+ :Al 3+ :SO4 2- The molar ratio is 2.5:0.8:1, and the residence time is 40min;

[0097] The wastewater in the tertiary reaction tank is pumped into the tertiary flocculation tank, and a polyacrylamide solution with a concentration of 0.4wt% is added to the tertiary flocculation tank, and slowly stirred. The fine suspended particles in the wastewater flocculate to form a gel feather, and then enter the tertiary sedimentation tank for sedimentation. The suspended gel feather settles to form sludge, and the sludge is pumped into the second physicochemical sludge tank, and the effluent enters the quaternary reaction tank;

[0098] The water quality data of the effluent from the tertiary sedimentation tank are: pH 11, fluoride concentration 4.92 mg / L, chloride concentration 826 mg / L, sulfate concentration 204 mg / L, and total nitrogen concentration 86 mg / L.

[0099] S5, add 30wt% lime water solution (flow rate 2.99m 3 / h) and 30wt% sodium aluminate solution (flow rate 1.59m 3 / h), maintaining Ca in the three-stage reaction pool system 2+ :Al 3+ :SO4 2- The molar ratio is 2.5:1.2:1, and the residence time is 40min;

[0100] The wastewater in the fourth-stage reaction tank is pumped into the fourth-stage flocculation tank, and a polyacrylamide solution with a concentration of 0.4wt% is added to the fourth-stage flocculation tank, and slowly stirred, so that the fine suspended particles in the wastewater flocculate to form a gel feather, and then enter the fourth-stage sedimentation tank for sedimentation. The suspended gel feather settles to form sludge, and the sludge is pumped into the second physicochemical sludge tank, and the effluent enters the fluorine-containing effluent pH adjustment tank;

[0101] The water quality data of the effluent from the fourth-stage sedimentation tank are: pH 13, fluoride concentration 4.5 mg / L, chloride concentration 210 mg / L, sulfate concentration 176 mg / L, and total nitrogen concentration 38 mg / L.

[0102] After the sludge in the second physicochemical sludge pool is filtered and dehydrated by the second filter press, the obtained dry sludge can be recycled for the preparation of coagulants, can also be used as heavy metal flocculation adsorbents, and can also be used as raw materials for cement manufacturing, realizing high-value resource recycling and turning waste into treasure; the filtrate from the second filter press is returned to the tertiary reaction tank;

[0103] S6. Add boric acid to the fluorine-containing effluent pH adjustment tank to adjust the pH value to 6.5. The effluent from the fluorine-containing effluent pH adjustment tank passes through the fluorine-containing Parshall trough and the fluorine-containing discharge tank in turn, meeting the "Battery Industry Pollutant Emission Standard" (GB30484-2013) and "Water Quality Standard for Sewage Discharge into Urban Sewers"

[0104] (GBT31962-2015) and the relevant emission requirements in the "Sichuan Province Water Pollutant Discharge Standard" and meet the emission standards.

[0105] Comparative Example 1

[0106] The fluorine-containing wastewater generated by the new energy industry in Example 2 is treated using conventional treatment processes to achieve that multiple indicators such as fluoride, chloride, sulfate, and total nitrogen in the wastewater meet the corresponding emission standards. The process route is: the comprehensive fluorine-containing wastewater first passes through a traditional two-stage defluorination system, then a three-stage deep defluorination system, and then enters a membrane treatment system after a hardness removal system, and finally is treated by an evaporation concentration system. For specific process flow, refer to Figure 2 ,include:

[0107] The comprehensive fluoride-containing wastewater enters the comprehensive fluoride-containing wastewater regulating tank, and then enters the primary pH regulating tank, the primary reaction tank, the primary coagulation tank, the primary flocculation tank, and the primary sedimentation tank in sequence;

[0108] The effluent from the primary sedimentation tank then enters the secondary pH adjustment tank, secondary reaction tank, secondary coagulation tank, secondary flocculation tank, and secondary sedimentation tank in sequence;

[0109] The effluent from the secondary sedimentation tank then enters the tertiary reaction tank, tertiary pH adjustment tank, tertiary flocculation tank, and tertiary sedimentation tank in sequence;

[0110] The effluent from the tertiary sedimentation tank enters the calcium and magnesium removal reaction tank, calcium and magnesium removal flocculation tank, calcium and magnesium removal sedimentation tank, pH adjustment tank in turn, and then passes through the membrane treatment system and evaporation concentration system.

[0111] The sludge from the primary sedimentation tank, the secondary sedimentation tank, the tertiary sedimentation tank, and the calcium and magnesium removal sedimentation tank enters the physical and chemical sludge tank. The sludge in the physical and chemical sludge tank is dehydrated by filter pressing and then outsourced for treatment. The filtrate is returned to the primary pH adjustment tank. The conventional treatment process can also treat the fluorine-containing wastewater to meet the standards, but compared with the process of Example 2, it requires the use of a membrane treatment system, an evaporation concentration system, etc., which has a large investment, a large footprint, and a high operating cost.

[0112] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to specific details.

Claims

1. A multi-index joint control and treatment system for fluorine-containing wastewater generated by the new energy industry, characterized in that: include: Primary defluorination subsystem, secondary defluorination subsystem, tertiary water treatment subsystem, quaternary water treatment subsystem and drainage subsystem; The primary defluorination subsystem comprises a comprehensive fluorine-containing wastewater regulating tank, a primary pH regulating reaction tank A, a primary pH regulating reaction tank B, a primary flocculation tank and a primary sedimentation tank connected in sequence; The secondary defluorination subsystem comprises a secondary pH adjustment reaction tank, a secondary reaction tank, a secondary coagulation tank, a secondary flocculation tank and a secondary sedimentation tank connected in sequence; The three-stage water treatment subsystem includes a three-stage reaction tank, a three-stage flocculation tank and a three-stage sedimentation tank connected in sequence; The four-stage water treatment subsystem includes a four-stage reaction tank, a four-stage flocculation tank and a four-stage sedimentation tank connected in sequence; The effluent from the primary sedimentation tank enters the secondary pH adjustment reaction tank, the effluent from the secondary sedimentation tank enters the tertiary reaction tank, the effluent from the tertiary sedimentation tank enters the quaternary reaction tank, and the effluent from the quaternary sedimentation tank enters the drainage subsystem.

2. The multi-index joint control and treatment system for fluorine-containing wastewater generated by the new energy industry according to claim 1 is characterized in that: The primary defluorination subsystem also includes an acid-containing wastewater regulating tank and an alkali-containing wastewater regulating tank, and the effluents of the acid-containing wastewater regulating tank and the alkali-containing wastewater regulating tank both enter the comprehensive fluorine-containing wastewater regulating tank.

3. The multi-index joint control and treatment system for fluorine-containing wastewater generated by the new energy industry according to claim 2 is characterized in that: The system also includes a first sludge treatment subsystem and a second sludge treatment subsystem.

4. The multi-index joint control and treatment system for fluorine-containing wastewater generated by the new energy industry according to claim 3 is characterized in that: The first sludge treatment subsystem comprises a first physicochemical sludge tank and a first filter press connected in sequence; The sludge in the primary sedimentation tank and the secondary sedimentation tank both enter the first physicochemical sludge tank, and the filtrate from the first filter press returns to the primary pH adjustment reaction tank A.

5. The multi-index joint control and treatment system for fluorine-containing wastewater generated by the new energy industry according to claim 4 is characterized in that: The second sludge treatment subsystem comprises a second physicochemical sludge tank and a second filter press connected in sequence; The sludge from the tertiary sedimentation tank and the quaternary sedimentation tank all enter the second physicochemical sludge tank, and the filtrate from the second filter press returns to the tertiary reaction tank.

6. The multi-index joint control and treatment system for fluorine-containing wastewater generated by the new energy industry according to claim 5 is characterized in that: The drainage subsystem comprises a fluorine-containing effluent pH adjustment tank, a fluorine-containing Parshall tank and a fluorine-containing discharge tank which are sequentially connected to the four-stage reaction tank.

7. A multi-index joint control treatment process for fluorine-containing wastewater generated by the new energy industry, characterized in that: The system as claimed in any one of claims 1 to 6 is used to treat fluorine-containing wastewater, which includes acid-containing wastewater and alkali-containing wastewater.

8. The multi-index joint control treatment process for fluorine-containing wastewater generated by the new energy industry according to claim 7, characterized in that: The process includes the following steps: S1. The acid-containing wastewater and the alkali-containing wastewater are transported to the acid-containing wastewater regulating tank and the alkali-containing wastewater regulating tank respectively, and then the wastewater in the acid-containing wastewater regulating tank and the alkali-containing wastewater regulating tank is pumped into the comprehensive fluorine-containing wastewater regulating tank; S2, pumping the comprehensive fluorine-containing wastewater in the comprehensive fluorine-containing wastewater regulating tank into the primary pH adjustment reaction tank A, adding lime water solution into the primary pH adjustment reaction tank A, and stirring, adjusting the pH value to 10-10.5, and the residence time is 5-30min; The wastewater in the primary pH adjustment reaction tank A is pumped into the primary pH adjustment reaction tank B, sulfuric acid solution is added to the primary pH adjustment reaction tank B, and stirred to adjust the pH value to 8.5-9.0, and the residence time is 10-40min; The wastewater in the primary pH adjustment reaction tank B is pumped into the primary flocculation tank, polyacrylamide is added to the primary flocculation tank, stirred and flocculated, and then enters the primary sedimentation tank for sedimentation. The sludge is pumped into the first physicochemical sludge tank, and the effluent enters the secondary pH adjustment reaction tank; S3, add lime water solution to the secondary pH adjustment reaction tank, and stir, adjust the pH value to 10, and the residence time is 2-10min; The wastewater in the secondary pH adjustment reaction tank is pumped into the secondary reaction tank, and calcium chloride solution is added to the secondary reaction tank, and stirred to maintain the calcium-fluoride molar ratio in the secondary reaction tank system at 0.5-0.6, and the residence time is 10-40 minutes; The wastewater in the secondary reaction tank is pumped into the secondary coagulation tank, and flocculants are added to the secondary coagulation tank with a retention time of 10-40 minutes; The wastewater in the secondary coagulation tank is pumped into the secondary flocculation tank, polyacrylamide is added to the secondary flocculation tank, stirred and flocculated, and then enters the secondary sedimentation tank for sedimentation. The sludge is pumped into the first physicochemical sludge tank, and the effluent enters the tertiary reaction tank; The sludge in the first physicochemical sludge tank is dehydrated by filtration and then outsourced for treatment, and the filtrate is returned to the primary pH adjustment reaction tank A; S4, add lime water solution and sodium aluminate solution to the tertiary reaction tank to maintain the Ca 2+ :Al 3 + :SO4 2- The molar ratio is 2:0.7:1-3:1:1, and the residence time is 20-80min; The wastewater in the tertiary reaction tank is pumped into the tertiary flocculation tank, polyacrylamide solution is added to the tertiary flocculation tank, stirred and flocculated, and then enters the tertiary sedimentation tank for sedimentation. The sludge is pumped into the second physicochemical sludge tank, and the effluent enters the quaternary reaction tank; S5, add lime water solution and sodium aluminate solution to the fourth-stage reaction tank to maintain the Ca content in the third-stage reaction tank system. 2+ :Al 3 + :SO4 2- The molar ratio is 2:1:1 to 3:1.5:1, and the residence time is 20-80min; The wastewater in the four-stage reaction tank is pumped into the four-stage flocculation tank, and the polyacrylamide solution is added to the four-stage flocculation tank, stirred and flocculated, and then enters the four-stage sedimentation tank for sedimentation. The sludge is pumped into the second physicochemical sludge tank, and the effluent enters the fluoride-containing effluent pH adjustment tank; The sludge in the second physicochemical sludge tank is filtered and dehydrated by the second filter press, and the obtained dry sludge is used to prepare coagulant, heavy metal flocculation adsorbent or cement; the filtrate of the second filter press is returned to the tertiary reaction tank; S6. Add boric acid to the fluorine-containing effluent pH adjustment pool to adjust the pH value to 6.5-9.

5. The effluent from the fluorine-containing effluent pH adjustment pool passes through the fluorine-containing Parshall tank and the fluorine-containing discharge pool in turn before meeting the discharge standards.

9. The multi-index joint control treatment process for fluorine-containing wastewater generated by the new energy industry according to claim 8, characterized in that: The flocculant in step S3 is at least one of polyaluminium chloride and polyaluminium sulfate.

10. The multi-index joint control treatment process for fluorine-containing wastewater generated by the new energy industry according to claim 9, characterized in that: The process includes the following steps: S1. The acid-containing wastewater and the alkali-containing wastewater are transported to the acid-containing wastewater regulating tank and the alkali-containing wastewater regulating tank respectively, and then the wastewater in the acid-containing wastewater regulating tank and the alkali-containing wastewater regulating tank is pumped into the comprehensive fluorine-containing wastewater regulating tank; S2, the comprehensive fluorine-containing wastewater in the comprehensive fluorine-containing wastewater regulating tank is pumped into the primary pH adjustment reaction tank A, and a lime solution with a concentration of 10wt% to 30wt% is added to the primary pH adjustment reaction tank A, and stirred to adjust the pH value to 10 to 10.5, and the residence time is 15min; The wastewater in the primary pH adjustment reaction tank A is pumped into the primary pH adjustment reaction tank B, and a 50wt% sulfuric acid solution is added to the primary pH adjustment reaction tank B, and stirred to adjust the pH value to 8.5-9.0, with a residence time of 20min; The wastewater in the primary pH adjustment reaction tank B is pumped into the primary flocculation tank, a polyacrylamide solution with a concentration of 0.4wt% is added to the primary flocculation tank, stirred and flocculated, and then enters the primary sedimentation tank for sedimentation. The sludge is pumped into the first physicochemical sludge tank, and the effluent enters the secondary pH adjustment reaction tank; S3, add 10wt% to 30wt% lime water solution into the secondary pH adjustment reaction tank, stir, adjust the pH value to 10, and the residence time is 5min; The wastewater in the secondary pH adjustment reaction tank is pumped into the secondary reaction tank, and a 30wt% calcium chloride solution is added to the secondary reaction tank, and stirred to maintain the calcium-fluorine molar ratio in the secondary reaction tank system at 0.5-0.6, and the residence time is 30min; The wastewater in the secondary reaction tank is pumped into the secondary coagulation tank, and a 10wt% polyaluminium chloride solution or a 10wt% polyaluminium sulfate solution is added to the secondary coagulation tank, the dosage is maintained at 1000-1500mg / L, and the residence time is 20min; The wastewater in the secondary coagulation tank is pumped into the secondary flocculation tank, and a polyacrylamide solution with a concentration of 0.4wt% is added to the secondary flocculation tank, stirred and flocculated, and then enters the secondary sedimentation tank for sedimentation. The sludge is pumped into the first physicochemical sludge tank, and the effluent enters the tertiary reaction tank; The sludge in the first physicochemical sludge tank is dehydrated by filtration and then outsourced for treatment, and the filtrate is returned to the primary pH adjustment reaction tank A; S4, add 30wt% lime water solution and 30wt% sodium aluminate solution to the tertiary reaction tank to maintain the Ca content in the tertiary reaction tank system. 2+ :Al 3+ :SO4 2- The molar ratio is 2:0.7:1-3:1:1, and the residence time is 40min; The wastewater in the tertiary reaction tank is pumped into the tertiary flocculation tank, a polyacrylamide solution with a concentration of 0.4wt% is added to the tertiary flocculation tank, stirred and flocculated, and then enters the tertiary sedimentation tank for sedimentation. The sludge is pumped into the second physicochemical sludge tank, and the effluent enters the quaternary reaction tank; S5, add 30wt% lime water solution and 30wt% sodium aluminate solution to the fourth-stage reaction tank to maintain the Ca content in the third-stage reaction tank system. 2+ :Al 3+ :SO4 2- The molar ratio is 2:1:1 to 3:1.5:1, and the residence time is 40min; The wastewater in the fourth-stage reaction tank is pumped into the fourth-stage flocculation tank, a polyacrylamide solution with a concentration of 0.4wt% is added to the fourth-stage flocculation tank, stirred and flocculated, and then enters the fourth-stage sedimentation tank for sedimentation. The sludge is pumped into the second physicochemical sludge tank, and the effluent enters the fluorine-containing effluent pH adjustment tank; The sludge in the second physicochemical sludge tank is filtered and dehydrated by the second filter press, and the obtained dry sludge is used to prepare coagulant, heavy metal flocculation adsorbent or cement; the filtrate of the second filter press is returned to the tertiary reaction tank; S6. Add boric acid to the fluorine-containing effluent pH adjustment pool to adjust the pH value to 6.5-9.

5. The effluent from the fluorine-containing effluent pH adjustment pool passes through the fluorine-containing Parshall trough and the fluorine-containing discharge pool in turn before meeting the discharge standards.

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