Method for removing total DNA (Deoxyribose Nucleic Acid) in wastewater with halide ion tolerance

Abstract

The invention provides a method for removing total DNA (Deoxyribose Nucleic Acid) in wastewater with halide ion tolerance, which is used for removing DNA in wastewater containing halide ions based on a potassium ferrate and calcium sulfite coupling system, and belongs to the technical field of sewage purification treatment. The method provided by the invention utilizes Fe (IV) / Fe (V) / Fe (VI) and flocculent precipitate which are not interfered by halide ions in the reaction of potassium ferrate and slightly soluble calcium sulfite to realize efficient removal of DNA in wastewater. According to the method, the oxidation stability under halide ion interference is remarkably improved, better environmental adaptability and more stable removal efficiency are shown, and a new technical scheme is provided for treatment of actual wastewater containing resistance genes.

Description

Technical Field

[0001] This invention belongs to the field of wastewater purification and treatment technology, specifically relating to a method for removing total DNA from wastewater with halide ion tolerance based on a potassium ferrate and calcium sulfite coupling system. Background Technology

[0002] With the acceleration of urbanization, the problem of genetic material pollution in wastewater treatment systems is becoming increasingly prominent. Existing research indicates that the DNA components in wastewater mainly originate from human excrement (37%-52%), medical wastewater (containing 16%-28% drug residue gene fragments), and environmental microbial communities (approximately 24%). Antibiotic resistance genes (ARGs), virulence factors (VFGs), and pathogen-specific marker genes carried in these genetic vectors can spread among environmental microorganisms through horizontal gene transfer (HGT) mechanisms, leading to a 3-5 order of magnitude increase in the proliferation rate of drug-resistant strains compared to natural conditions, seriously threatening drinking water safety and ecological health. In particular, certain types of DNA can cause harm to the environment and public health. For example, if drug resistance genes (ARGs), pathogen genes, and virulence factor genes (VFGs) are transferred to bacteria harmful to humans, animals, and plants, it will significantly increase public health risks. Therefore, the removal of DNA from wastewater treatment plants has received widespread attention.

[0003] Current DNA removal technologies (including biological, physical, and chemical treatments) face significant environmental adaptability challenges in practical applications, particularly in the treatment of wastewater containing halogen ions such as chloride and bromine (e.g., aquaculture wastewater, medical wastewater, and pharmaceutical wastewater). These types of wastewater commonly exhibit the coexistence of halogen ions and DNA, with chloride ions (Cl...) being particularly prevalent. - ) and bromide ions (Br - The abundance of these halogen ions is relatively high. Studies have found that the presence of these halogen ions significantly inhibits the removal efficiency of DNA in actual wastewater. Common physical methods, such as adsorption (e.g., activated carbon adsorption), mainly rely on physical and chemical adsorption mechanisms, including pore filling, hydrogen bonding, π-π interactions, electrostatic interactions, and functional group complexation, to achieve the physical enrichment of DNA. Their limitation is that only DNA transfer occurs without decomposing the DNA to render it ineffective; subsequent adsorption still requires desorption of the adsorbent to degrade and treat the DNA. In contrast, advanced oxidation processes (AOP) can directly decompose DNA in wastewater by generating strong oxidants (such as hydroxyl radicals (·OH)). However, the presence of halogen ions can react with ·OH and sulfate radicals (SO42-). ·- The reactive free radicals such as Br₂ and OH₂ react and are removed, forming less reactive halogen compounds (RHS). If removed using an advanced oxidation process based on ·OH, Br₂... - As the primary free radical scavenger, its presence significantly affects oxidation efficiency. Experimental studies have shown that Br...- The scavenging rate of ·OH can reach 93%, therefore Br - The presence of [a substance] leads to the consumption of strong oxidants, thereby reducing the DNA removal rate. If an SO4-based [method] is used... ·- Advanced oxidation processes remove DNA, dichloro radicals (Cl2) ·- The presence of ) will increase the patching repair of ARGs and SO4. ·- Potential risks associated with vertical gene transfer of ARGs mediated by disinfection, reducing SO4 ·- DNA removal rate mediated by treatment. When using patent CN115991532A to treat halide-containing wastewater, in Cl... - With Br - Under interference, the active species ·OH and SO4 generated in the sodium sulfite-potassium ferrate coupling system ·- Will with Cl - and Br - The reaction produces reactive chlorine (RCS) and reactive bromine (RBS) with low redox potentials, which leads to a decrease in the concentration of active species and a significant decrease in the total DNA removal rate.

[0004] For practical wastewater treatment scenarios containing halogen ions such as chlorine and bromine, existing technologies generally suffer from low DNA removal efficiency due to halogen ion interference. To overcome this limitation, this invention innovatively proposes a treatment process based on a coupling system of potassium ferrate and calcium sulfite, and is based on the actual wastewater containing Cl... - (170-234 mg / L) and Br - A systematic experimental design was conducted with a concentration range of (0-50 mg / L) (Luque et al, 2024; Zhang et al, 2025; Soltermann et al, 2016). The experimental results showed that the coupled system exhibited significant advantages in wastewater environments containing halogen ions such as chlorine and bromine, achieving a dual improvement in DNA removal efficiency and environmental adaptability, and providing a new technical approach for the control of biological pollution under complex water quality conditions. Summary of the Invention

[0005] To overcome the shortcomings of the existing technology, the present invention provides a method for removing total DNA from wastewater with halide ion tolerance based on a potassium ferrate and calcium sulfite coupling system.

[0006] The technical solution adopted in this invention is as follows:

[0007] A method for removing total DNA from wastewater with halide ion tolerance involves using a coupling system of potassium ferrate and calcium sulfite to remove DNA from wastewater containing halide ions.

[0008] Furthermore, in the method for removing total DNA from wastewater with halide ion tolerance, the halide ions are chloride ions or bromide ions.

[0009] Furthermore, in the method for removing total DNA from wastewater with halide ion tolerance, when the halide ion is chloride ion, the molar ratio of potassium ferrate, calcium sulfite and chloride ion is 1:2:(27-31.5).

[0010] Furthermore, in the method for removing total DNA from wastewater with halide ion tolerance, when the halide ion is bromide ion, the molar ratio of potassium ferrate, calcium sulfite and bromide ion is 1:2:(0.2-2).

[0011] Furthermore, in the method for removing total DNA from wastewater with halide ion tolerance, the pH of the wastewater is 6.5-7.5.

[0012] Furthermore, the method for removing total DNA from wastewater with halide ion tolerance includes the following steps: adding potassium ferrate and calcium sulfite to wastewater containing halide ions and DNA, immediately stirring rapidly, then stirring slowly, and the supernatant separated after settling is the purified water.

[0013] Furthermore, the method for removing total DNA from wastewater with halide ion tolerance is described above, wherein the removal method is carried out at room temperature.

[0014] Furthermore, in the method for removing total DNA from wastewater with halide ion tolerance, the rapid stirring speed is 600-800 rpm and the rapid stirring time is 1-2 min.

[0015] Furthermore, in the method for removing total DNA from wastewater with halide ion tolerance, the slow stirring speed is 50-100 rpm and the slow stirring time is 15-30 min.

[0016] Furthermore, in the method for removing total DNA from wastewater with halide ion tolerance, the settling time is 30 minutes.

[0017] The beneficial effects of this invention are as follows:

[0018] 1. In actual wastewater treatment containing halogen ions such as chlorine and bromine, the potassium ferrate-sodium sulfite coupling system has significant technical limitations. Halogen ions react with ·OH and SO4. ·- The reaction leads to a significant decrease in the effective oxidant concentration in the system, thus affecting the efficiency of DNA removal. In contrast, the potassium ferrate-calcium sulfite coupling system, due to the slight solubility of calcium sulfite, allows for a reduction in the concentration of soluble SO3 within the system.2- The concentration remained at an extremely low level, and the concentration of hexavalent iron (Fe(VI)) was much higher than that of SO3. 2- At this point, Fe(VI) can exceed 1.9 × 10⁻⁶. 8 m -1 s -1 The rate constant competes with O2 for trace amounts of SO3. ·- Meanwhile, the solubility of calcium sulfite limits the amount of soluble SO3. 2- The release, and the released SO3 2- It will be immediately oxidized by Fe(VI), resulting in [SO3] 2- The [Fe(VI)] ratio was maintained at an extremely low level, thereby suppressing SO42-. ·- The formation of ·OH groups means that the system's DNA removal primarily relies on pentavalent iron (Fe(V)) and tetravalent iron (Fe(IV)), which are less affected by inorganic anions. It's worth noting that unreacted Fe(VI) can also contribute to DNA removal by inducing damage to microbial DNA. Therefore, this system can maintain a high DNA removal rate even under halide ion interference, effectively overcoming the technical bottleneck of the sharp drop in efficiency of sodium systems in halide-containing wastewater.

[0019] 2. In the potassium ferrate and calcium sulfite coupling system, Fe(V) / Fe(IV) has a high redox potential. It can destroy DNA / RNA through its high oxidizing power, thereby causing irreversible oxidative damage to the cell membrane, achieving the purpose of destroying ARGs and reducing the pollution of antibiotic ARGs in the water environment.

[0020] 3. The potassium ferrate and calcium sulfite coupling system exhibits significant advantages over the potassium ferrate and sodium sulfite coupling system. The key difference lies in the formation mechanism of the active species: the former mainly produces Fe(V) / Fe(IV), which has a significant effect on the Cl- in wastewater. - / Br - Inorganic anions exhibit strong anti-interference properties, while the latter depends on ·OH and SO42-. ·- It readily reacts with halide ions to form halogenated compounds (RHS). Kinetic studies show that in acidic aqueous solutions, the half-life of Fe(IV) (t1 / 2≈10 s) is longer than that of ·OH (t1 / 2≈10 s). -9 The time difference, extended by 10 orders of magnitude, allows for a longer reaction contact time for ferric iron, resulting in a more sustained oxidation effect. Furthermore, the iron oxides and hydroxides produced by Fe(VI) / Fe(V) / Fe(IV) reduction act as coagulants, further removing total DNA. These synergistic effects give the potassium ferrate and calcium sulfite coupling system more stable removal performance and better environmental adaptability in chlorinated and bromine-containing wastewater.

[0021] 4. Compared to potassium ferrate alone, calcium sulfite plays a crucial catalytic activation role in the potassium ferrate and calcium sulfite coupled system. Calcium sulfite can efficiently convert Fe(VI) into highly active Fe(IV) / Fe(V) through a single-electron transfer process. The generated Fe(IV) / Fe(V) can efficiently and rapidly oxidize various organic pollutants, with an oxidation rate 6.1 to 173.7 times higher than that of Fe(VI) alone. Furthermore, experiments have shown that the potassium ferrate and calcium sulfite coupled system significantly improves DNA removal efficiency, increasing it from 32.46%-45.97% when Fe(VI) is used alone to 79.50-86.80%. Attached Figure Description

[0022] Figure 1 This is a comparison of the removal rates of total genomic DNA by the K2FeO4 / CaSO3 and K2FeO4 / Na2SO3 coupled systems and the K2FeO4 system under different chloride ion concentrations in Example 1.

[0023] Figure 2 This is a comparison chart of the relative LDH levels of the K2FeO4 / CaSO3 and K2FeO4 / Na2SO3 coupled systems and the K2FeO4 system under different chloride ion concentrations in Example 1.

[0024] Figure 3 This is a comparison of the removal rates of total genomic DNA by the K2FeO4 / CaSO3 and K2FeO4 / Na2SO3 coupled systems and the K2FeO4 system under different bromide ion concentrations in the presence of chloride ions in Example 1.

[0025] Figure 4 This is a comparison of the relative LDH levels of the K2FeO4 / CaSO3 and K2FeO4 / Na2SO3 coupled systems and the K2FeO4 system under different bromide ion concentrations in the presence of chloride ions in Example 1. Detailed Implementation

[0026] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0027] Example 1

[0028] In this example, actual wastewater was used as the influent, taken from the effluent of a laboratory-operated sequencing batch reactor (SBR). The SBR system was also subjected to directional culture with the addition of erythromycin thiocyanate to enrich ARGs in the effluent. Water quality analysis showed that the wastewater had a COD concentration of 480 mg / L, an NH3-N concentration of 42.4 mg / L, a TP concentration of 10 mg / L, and a Cl concentration of... - The concentration is 170 mg / L, Br -The concentration is 0 mg / L. The specific steps include:

[0029] The experimental setup consisted of a series of 1L beakers, each containing 100mL of supernatant from a sequencing batch reactor (SBR) after sedimentation. Two reaction systems were configured, maintaining a 1:2 molar ratio of potassium ferrate to sulfite. Sodium chloride and potassium bromide were used for Cl- reactions, respectively. - and Br - The specific experimental procedure for the addition of the reagent is shown in Table 1. After the reagent is added, it is immediately stirred vigorously at 600 rpm for 2 minutes, and then slowly stirred at 100 rpm for 20 minutes. The beaker is then left to stand still and allowed to settle naturally for 30 minutes. The reaction is carried out at room temperature, and the pH of the wastewater is 6.5-7.5.

[0030] Take the water sample processed in the above steps, and collect the supernatant after drug treatment using a 0.22 μm aqueous filter membrane to retain bacteria and DNA in the supernatant; simultaneously, collect the precipitate after drug treatment using a 0.22 μm aqueous filter membrane to retain bacteria and DNA in the precipitate. The filtered membrane is then used for DNA extraction.

[0031] Table 1 Experimental scheme for the K2FeO4+Na2SO3 system

[0032]

[0033] Table 2 Experimental scheme for the K2FeO4+CaSO3 system

[0034]

[0035] Table 3 Experimental scheme for K2FeO4 system

[0036]

[0037] The effects of K₂FeO₄ / CaSO₃ and K₂FeO₄ / Na₂SO₃ coupled systems and the K₂FeO₄ system on DNA removal in actual wastewater under different chloride ion concentrations are as follows: Figure 1 , Figure 2 As shown. Figure 1 This chart compares the removal rates of total genomic DNA by the K2FeO4 / CaSO3 and K2FeO4 / Na2SO3 coupled systems and the K2FeO4 system under different chloride ion concentrations. The data shows that the removal rates of total genomic DNA by the K2FeO4 / Na2SO3 (group A1) and K2FeO4 / CaSO3 (group B1) coupled systems were significantly higher than those by using K2FeO4 alone (group C1 had a removal rate of only 45.97%), reaching 85.51% and 79.50%, respectively. At this point, the removal rate of group B1 was lower than that of group A1. However, with the increase of chloride ion concentrations...- With increasing concentration, the DNA removal rate of the K2FeO4 / Na2SO3 system showed a decreasing trend. The removal rates of groups A2, A3, and A4 decreased to 80.95%, 72.14%, and 66.97%, respectively, indicating that the system was affected by Cl. - The interference was significant, and the removal rate fluctuated considerably; in contrast, the K2FeO4 and K2FeO4 / CaSO3 systems were affected by Cl... - The interference was small; the DNA removal rates of groups C1-C4 were 45.97%, 42.18%, 41.71%, and 48.81%, respectively, while the DNA removal rates of groups B1-B4 reached 79.50%, 76.13%, 75.72%, and 74.76%, respectively. This indicates that the K2FeO4 / CaSO3 coupling system has low interference in Cl - It exhibits a more stable and efficient DNA removal rate under interference and has a stronger resistance to environmental interference, making it more suitable for the treatment of wastewater containing halogen ions such as chlorine and bromine.

[0038] The reaction equation for the coupled system of potassium ferrate and calcium sulfite is as follows:

[0039] Fe (VI) O4 2- +SO3 2- →HFe (V) O4 2- +SO3 ·- (1)

[0040] 2HFe (V) O4 2- +2SO3 2- +4H₂O→2Fe (Ⅲ) OH3+2SO4 2- +4OH - (2)

[0041] 2HFe (V) O4 2- +2H + +2H₂O→2Fe (Ⅲ) OH3 + 2H2O2 (3)

[0042] The reaction equation for the coupled system of potassium ferrate and sodium sulfite is as follows:

[0043] Fe 6+ + SO3 2- → Fe 5+ + SO3 •- (4)

[0044] SO3 •- + O2→ SO5 •- (5)

[0045] SO5 •- + SO3 2- → SO4 •- + SO4 2- (6)

[0046] SO4 •- + OH - → SO4 2- + HO· (7)

[0047] Fe 5+ + H2O → Fe 3+ + H2O2 (8)

[0048] Fe 6+ + H2O2 → Fe 4+ + O2 (9)

[0049] SO4 •- + H2O → SO4 2- + HO· + H + (10)

[0050] Fe 6+ + H2O → Fe 3+ (11)

[0051] Fe 3+ + OH - → Fe(OH)3 (12)

[0052] The reaction equation for the potassium ferrate system is as follows:

[0053] FeO4 2- + 8H + + 3e - →Fe(III) + 4H2O (13)

[0054] Figure 2This chart compares the relative LDH levels of the K₂FeO₄ / CaSO₃ and K₂FeO₄ / Na₂SO₃ coupled systems and the K₂FeO₄ system at different chloride ion concentrations. Since impaired cell membrane integrity leads to the leakage of intracellular lactate dehydrogenase (LDH), causing an increase in relative LDH levels, changes in relative LDH levels can be used as an indicator to assess the degree of bacterial damage caused by the system. In groups A1, A2, A3, and A4 treated with the K₂FeO₄ / Na₂SO₃ system, the relative LDH levels were 160.12%, 139.41%, 121.46%, and 106.85%, respectively. In groups B1, B2, B3, and B4 treated with the K₂FeO₄ / CaSO₃ system, the relative LDH levels were 152.88%, 147.29%, 143.24%, and 141.90%, respectively. In the C1, C2, C3, and C4 groups treated with the K₂FeO₄ system, the relative LDH levels were 145.59%, 140.98%, 141.91%, and 141.15%, respectively. The experimental results showed that the K₂FeO₄ / CaSO₃, K₂FeO₄ / Na₂SO₃, and K₂FeO₄ systems could all disrupt bacterial oxidative stress balance, increase cell membrane permeability, and thus damage bacteria. However, the K₂FeO₄ / Na₂SO₃ system showed the best results in terms of LDH levels in Cl₂FeO₄ / CaSO₃ / Na₂SO₃ / Na₂SO₃ / C₂FeO₄ ... - The relative LDH level in the environment varied significantly more than that in the K2FeO4 / CaSO3 and K2FeO4 systems, influenced by Cl. - The interference is significant. It is worth noting that while the K₂FeO₄ / CaSO₃ system efficiently removes DNA, the relative LDH level change is significantly smaller than that of the K₂FeO₄ / Na₂SO₃ system, which is more effective at removing Cl₂. - It exhibits stronger resistance to interference, demonstrating significant advantages in practical applications.

[0055] Due to Cl - It is widely present in aquatic environments and is unavoidable in actual wastewater, and Cl... - With Br - Compared to other halide ions, which have higher abundance in actual wastewater, this experiment set up combinations of chloride ions with different concentrations of bromide ions to simulate the coexistence of halide ions that may occur in actual wastewater. This more realistically reflects the effects of the two systems, K2FeO4 / CaSO3 and K2FeO4 / Na2SO3, in actual halide-containing wastewater, thus providing a reliable basis for optimizing total DNA removal methods in wastewater in practical applications. Figure 3 , Figure 4 The effects of K₂FeO₄ / CaSO₃ and K₂FeO₄ / Na₂SO₃ coupled systems and the K₂FeO₄ system on DNA removal in actual wastewater under different bromide ion concentrations in the presence of chloride ions are presented. Figure 3This chart compares the removal rates of total genomic DNA by the K2FeO4 / CaSO3 and K2FeO4 / Na2SO3 coupled systems and the K2FeO4 system under different bromide ion concentrations in the presence of chloride ions. The removal rates for groups A5, A6, A7, and A8 treated with the sodium sulfite system were 65.03%, 61.82%, 45.50%, and 32.23%, respectively. The removal rates for groups B5, B6, B7, and B8 treated with the calcium sulfite system were 86.80%, 82.03%, 81.28%, and 80.80%, respectively. The removal rates for groups C5, C6, C7, and C8 treated with only the potassium ferrate system were 32.46%, 28.07%, 33.33%, and 35.61%, respectively. Experimental results show that, under conditions of multiple halide ion coexistence, the K₂FeO₄ / CaSO₃ coupling system exhibits superior stability compared to the K₂FeO₄ / Na₂SO₃ system, and demonstrates a higher DNA removal rate compared to the K₂FeO₄ system. It is noteworthy that the presence of Br₂... - The effect of sodium sulfite on the system is much greater than that of Cl alone when it is present. - The existence of this system is due to the fact that the active species generated by the sodium sulfite system are mainly ·OH and SO4. ·- ·OH can react with Cl - and Br - The reaction produces RCS and RBS, which have low redox potentials. Although the production pathways of RCS and RBS are similar, they react with ClOH under neutral conditions. ·- In comparison, only 24% BrOH ·- Regenerated into ·OH and Br - This led to Br - In an environment where OH is lower than Cl - Environment, which explains why Br - The effect of sodium sulfite on the system is much greater than that on Cl when it is present. - The Fe(V) / Fe(IV) ratio generated in the calcium sulfite system is less affected by inorganic anions, thus resulting in a stable removal rate.

[0056] Cl - +·OH→ClOH ·- (14)

[0057] ClOH ·- →·OH+Cl - (15)

[0058] Br - +·OH→BrOH ·- (16)

[0059] BrOH ·- →Br- +·OH (17)

[0060] Figure 4 A comparison of relative LDH levels in the K₂FeO₄ / CaSO₃ and K₂FeO₄ / Na₂SO₃ coupled systems and the K₂FeO₄ system under different bromide ion concentrations in the presence of chloride ions. The relative LDH levels of groups A5, A6, A7, and A8 treated with the K₂FeO₄ / Na₂SO₃ system were 147.36%, 136.84%, 121.81%, and 114.03%, respectively. The relative LDH levels of groups B5, B6, B7, and B8 treated with the K₂FeO₄ / CaSO₃ system were 143.10%, 141.16%, 141.52%, and 141.56%, respectively. The relative LDH levels of groups C5, C6, C7, and C8 treated with the K₂FeO₄ system were 145.59%, 147.27%, 144.59%, and 142.33%, respectively. In an environment where multiple halide ions coexist, the relative LDH level of K2FeO4 / Na2SO3 changes significantly more than that of the K2FeO4 / CaSO3 system. This further confirms that the K2FeO4 / CaSO3 system exhibits less fluctuation in response to the influence of inorganic anions, demonstrating the system's good environmental adaptability.

[0061] In summary, compared to the K2FeO4 / Na2SO3 system, the K2FeO4 / CaSO3 system produces mainly Fe(VI) and Fe(IV) (2.20V), which are less affected by inorganic anions in water and are efficiently generated from Fe(VI) and calcium sulfite via a single-electron transfer step. However, the K2FeO4 / Na2SO3 system produces ·OH (2.7V in acidic conditions, 1.8V in alkaline conditions) and SO42-, which are more significantly affected by inorganic anions in water. ·- (2.5-3.1V). Fe(V) / Fe(IV) can resist the influence of inorganic ions in water; however, ·OH and SO42- are also affected. ·- Will with Cl - and Br -The reaction consumes DNA, resulting in lower redox potentials (RCS and RBS), thus reducing the removal efficiency and relative LDH level of the K2FeO4 / Na2SO3 system. While both the K2FeO4 / CaSO3 and K2FeO4 systems use Fe(V) / Fe(IV) / Fe(VI) as the main active species, CaSO3 exhibits a unique catalytic activation function in the potassium ferrate and calcium sulfite coupling system. It effectively activates Fe(VI) through a single-electron transfer mechanism, significantly promoting the in-situ instantaneous conversion of Fe(VI) into highly active Fe(IV) and Fe(V), greatly improving DNA removal efficiency. Therefore, the K2FeO4 / CaSO3 coupling system has superior performance compared to the K2FeO4 / Na2SO3 coupling system and the K2FeO4 system. This system not only has a higher DNA removal rate but also better environmental adaptability, being less affected by fluctuations in environmental water quality, making it more suitable for treating wastewater containing halogen ions such as chlorine and bromine.

[0062] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for removing total DNA in wastewater having halide resistance, characterized by, The removal method is to remove DNA in wastewater containing halide ions by using a coupling system of potassium ferrate and calcium sulfite.

2. The method for removing total DNA in wastewater having halide resistance according to claim 1, characterized by, The halide ion is chloride ion or bromide ion.

3. The method for removing total DNA in wastewater having halide resistance according to claim 2, characterized by, When the halide ion is chloride ion, the molar ratio of potassium ferrate, calcium sulfite and chloride ion is 1:2:(27-31.5).

4. The method for removing total DNA in wastewater having halide resistance according to claim 2, characterized by, When the halide ion is bromide ion, the molar ratio of potassium ferrate, calcium sulfite and bromide ion is 1:2:(0.2-2).

5. The method of claim 1, wherein the method is a method for removing total DNA in wastewater having halide resistance. The pH of the wastewater is 6.5-7.

5.

6. The method of claim 1, wherein the method is a method for removing total DNA in wastewater having halide resistance. The removal method comprises the following steps: adding potassium ferrate and calcium sulfite into wastewater containing halide ions and DNA, immediately stirring rapidly, then stirring slowly, and separating the supernatant after standing and settling.

7. The method for removing total DNA in wastewater having halide resistance according to claim 6, characterized by, The removal method is carried out at room temperature.

8. The method of claim 6, wherein the method is a method for removing total DNA in wastewater having halide resistance. The stirring speed is 600-800 rpm, and the rapid stirring time is 1-2 min.

9. The method of claim 6, wherein the method is a method for removing total DNA in wastewater having halide resistance. The slow stirring speed is 50-100 rpm, and the slow stirring time is 15-30 min.

10. The method of claim 6, wherein the method is for removing total DNA in wastewater having halide resistance. The standing and settling time is 30 min.

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