A synergistic treatment process for phytic acid wastewater and heavy metal wastewater

Abstract

This invention belongs to the technical field of wastewater treatment, specifically relating to a synergistic treatment process and system for phytic acid wastewater and heavy metal wastewater. Heavy metal wastewater and phytic acid wastewater are added to a wastewater mixing reaction tank for mixing and reaction. The resulting wastewater mixture flows by gravity to a coagulation tank 1, forming large flocs. It then flows by gravity to a sedimentation tank 1 for sludge-water separation. The resulting upper portion of wastewater flows by gravity to a pH adjustment tank, and then flows to a multi-functional reaction tank, a coagulation tank 2, and a sedimentation tank 2 for further sludge-water separation. The upper portion of wastewater flows by gravity to an intermediate water tank for temporary storage. It is then lifted by a wastewater lifting device to a pulse distributor, and finally fed into a biological treatment unit for further treatment, ensuring the effluent meets discharge standards. Phytic acid wastewater can act as a nutrient, addressing the low C / N ratio in heavy metal wastewater. The high biodegradability of phytic acid wastewater improves the biodegradability of heavy metal wastewater, increasing the B / C ratio in the wastewater.

Description

Technical Field

[0001] This invention belongs to the technical field of wastewater treatment, specifically relating to a synergistic treatment process and system for phytic acid wastewater and heavy metal wastewater. Background Technology

[0002] The main pollutants in phytic acid wastewater are organic matter, total phosphorus, and suspended solids. Most of the organic matter in the wastewater is phytate ions, and the wastewater has good biodegradability. Phytate ions in phytic acid wastewater can complex with most heavy metal ions to form precipitates, and the concentration of organic matter in phytic acid wastewater is in the thousands or even tens of thousands of milligrams per liter, indicating good biodegradability. However, the wastewater contains a large amount of phosphate. Electroplating wastewater, on the other hand, has a high content of heavy metal ions, such as copper, nickel, and tin, and a low organic matter content, often making it difficult to biodegrade. Electroplating wastewater also has a low C / N ratio, requiring nutrient supplementation during the biodegradation process.

[0003] Typically, the COD in phytic acid wastewater Cr Concentrations between 10,000 and 20,000 mg / L, ammonia nitrogen content less than 20 mg / L, COD in electroplating wastewater Cr With a concentration of 150–500 mg / L and an ammonia nitrogen concentration of 50–300 mg / L, this invention proposes a synergistic treatment method for phytic acid wastewater and heavy metal wastewater to address the wastewater treatment problem. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide a synergistic treatment process and system for phytic acid wastewater and heavy metal wastewater. By utilizing the synergistic treatment of phytic acid wastewater and heavy metal wastewater, the phytic acid wastewater can act as a nutrient, solving the problem of low C / N value in heavy metal wastewater. The phytic acid wastewater has high biodegradability, thereby improving the biodegradability of heavy metal wastewater.

[0005] The technical content of this invention is as follows:

[0006] The present invention also provides a synergistic treatment system for phytic acid wastewater and heavy metal wastewater. The treatment system includes a wastewater mixing reaction tank, a coagulation tank 1, a sedimentation tank 1, a pH adjustment tank, a multifunctional reaction tank, a coagulation tank 2, a sedimentation tank 2, an intermediate water tank, a wastewater lifting device, and a biochemical treatment unit connected in sequence.

[0007] It also includes a phytic acid wastewater quantitative dosing unit, a sludge pump, a filter press, an aeration unit, and a dosing device;

[0008] The wastewater mixing reaction tank is connected to the phytic acid wastewater quantitative dosing unit;

[0009] The phytic acid wastewater quantitative dosing unit is equipped with equipment such as a quantitative pump, a mixer, and a level gauge;

[0010] The biochemical treatment system includes a pulse water distributor and a biochemical treatment tank connected in sequence.

[0011] The biochemical treatment tank is connected to an aeration unit on one side and to a sludge pump and a filter press on the other side in sequence.

[0012] The sludge pump is connected to sedimentation tank 1, sedimentation tank 2 and biochemical treatment unit.

[0013] This invention also provides a synergistic treatment process for phytic acid wastewater and heavy metal wastewater, comprising the following steps:

[0014] Heavy metal wastewater and phytic acid wastewater are added to the wastewater mixing reaction tank for mixing and reaction. The resulting wastewater mixture flows by gravity to the coagulation tank 1, where it forms large flocs. Then, it flows by gravity to the sedimentation tank 1 for mud-water separation. The resulting upper wastewater flows by gravity to the pH adjustment tank, and then flows to the multi-functional reaction tank, coagulation tank 2, and sedimentation tank 2 for mud-water separation. The upper wastewater flows by gravity to the intermediate water tank for temporary storage. Then, the wastewater is lifted by the wastewater lifting device to the pulse water distributor, and then fed into the biological treatment unit for wastewater treatment, so that the effluent meets the discharge standards.

[0015] Inorganic coagulant PAC (or iron salt) and flocculant PAM are added to gelation tank 1 and gelation tank 2 respectively;

[0016] The pH adjustment tank is used to adjust the pH of the wastewater to 7.5–12.

[0017] The biochemical treatment unit adopts an anaerobic + aerobic treatment process or an anaerobic + anoxic + aerobic treatment process. The anaerobic treatment uses COD-reducing, highly efficient salt-tolerant bacteria, and the aerobic treatment uses self-acclimated salt-tolerant bacteria.

[0018] The biochemical treatment unit adopts an anaerobic + aerobic treatment process or an anaerobic + anoxic + aerobic treatment process. The anaerobic treatment uses COD-reducing, highly efficient salt-tolerant bacteria, which is a mixture of Lactobacillus spp. (CICC 23053) and biological enzymes. After activating Lactobacillus spp., 6% wt Lactobacillus spp. solution and 5% biological enzymes are added to the wastewater.

[0019] The activation culture medium consists of 20.0 g / L glucose, 10.0 g / L yeast extract, 10.0 g / L peptone, 10.0 g / L sodium acetate, and 5.0 ml / L salt solution at pH 6.8. The salt solution formula is: 40.0 g / L MgSO4·7H2O, 2.0 g / L MnSO4·4H2O, 2.0 g / L FeSO4·7H2O, and 2.0 g / L NaCl.

[0020] The aerobic treatment employs self-acclimated salt-tolerant bacteria, which is a mixture of Bacillus circulatoryus (CICC23053), Coxella roseum (CICC 20758), and biological enzymes. Bacillus circulatoryus and Coxella roseum are activated and acclimated separately. 6% wt Bacillus circulatoryus solution, 8% wt Coxella roseum solution, and 5% wt biological enzymes are added to the wastewater after acclimation.

[0021] In the aerobic treatment, the dissolved oxygen in the aerobic tank is controlled between 2 and 4 mg / L;

[0022] The activation medium consisted of 5.0 g / L peptone, 3.0 g / L beef extract, 5.0 g / L NaCl, 5 mg / L MnSO4·H2O, 15.0 g / L agar, and pH 7.0.

[0023] The acclimatization culture medium is composed of a mixture of phytic acid wastewater and heavy metal wastewater sterilized at high temperature, diluted with water to 50-60% of the original concentration, inoculated with 5% by volume of Bacillus circulatoryus and Coxella rosea after activation culture, and cultured at room temperature and 150-180 rpm for 60 days to obtain Bacillus circulatoryus acclimatization solution and Coxella rosea acclimatization solution, respectively.

[0024] The sludge from sedimentation tank 1, sedimentation tank 2 and the biochemical treatment unit is pumped out by a sludge discharge pump, dewatered by a plate and frame filter press, and then transported off-site.

[0025] The phytic acid wastewater comes from the wastewater generated during the production of phytic acid, sodium phytate, and inositol series products. The phytic acid in the wastewater forms complexes with metal ions. Phytic acid is also known as inositol hexaphosphate / cyclohexanehexaphosphate phytic acid. The ability of phytic acid to complex metal ions comes from the electron-rich nature of the phosphate groups in its molecule.

[0026] The heavy metal wastewater originates from electroplating wastewater or circuit board wastewater containing heavy metal ions.

[0027] The precipitation principle of phytic acid with metal ions used in this invention is as follows: Phytic acid has six phosphate groups in its structure, which have a strong metal ion complexing effect. Phytic acid's ability to complex metal ions comes from the electron-rich nature of its phosphate groups, and it is a multi-coordinate compound containing six phosphate groups. Its complexing ability is similar to EDTA, but it is more stable. Phytic acid can qualitatively precipitate divalent and higher valence metal salts. The stability order of the formed complexes is Mg... 2+ <Ca 2+ <Cu 2+ <Ni 2+ Phytic acid wastewater can be effectively removed from electroplating wastewater by quantitatively adding it to the wastewater.

[0028] The beneficial effects of this invention are as follows:

[0029] The present invention relates to a synergistic treatment process and system for phytic acid wastewater and heavy metal wastewater. Phytic acid wastewater acts as a nutrient, addressing the problem of low C / N ratios in heavy metal wastewater (generally C / N < 5, with C / N < 1 in circuit board copper-ammonia wastewater). The high biodegradability of phytic acid wastewater improves the biodegradability of heavy metal wastewater, increasing the B / C ratio (generally B / C < 0.15). The mixing of phytic acid wastewater and heavy metal wastewater can also result in chelation precipitation under acidic conditions, eliminating the need to adjust the pH value of the wastewater. This reduces reagent dosage costs, decreases sludge production, achieves sludge reduction, and lowers sludge disposal costs. Attached Figure Description

[0030] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0031] The present invention will be further described in detail below through specific implementation examples and accompanying drawings. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of protection of the present invention. After reading the present invention, any modifications of the present invention in various equivalent forms by those skilled in the art fall within the scope of the appended claims.

[0032] Unless otherwise specified, all raw materials and reagents used in this invention are from the conventional market.

[0033] Example

[0034] A co-treatment process for acidic wastewater and heavy metal wastewater

[0035] Heavy metal wastewater from electroplating plants, including copper-containing complex wastewater, was selected; phytic acid wastewater from phytic acid production and rice bran soaking wastewater were also selected.

[0036] Heavy metal wastewater and phytic acid wastewater are added to a wastewater mixing reaction tank at a ratio of 30:1. The mixture is thoroughly mixed and reacted under the action of a stirrer. The resulting wastewater mixture flows by gravity to a coagulation tank 1. 100-500 mg / L of inorganic coagulant PAC (or iron salt) and 1-5 mg / L of flocculant PAM are added to the wastewater in the coagulation tank 1. Through the bridging, charge neutralization and trapping effects of the flocculants, small particles in the water gradually aggregate to form large particles, eventually forming relatively large flocs, which accelerates the sedimentation rate of the particles. The wastewater mixture flows by gravity to a sedimentation tank 1 for mud-water separation. The flocs are concentrated and settled by gravity. The resulting upper wastewater flows by gravity to a pH adjustment tank. An automatic pH monitor is installed in the pH adjustment tank, and alkali solution is automatically added to adjust the pH to 7.5-12.

[0037] The wastewater then flows sequentially to the multi-functional reaction tank, coagulation tank 2, and sedimentation tank 2 for mud-water separation, gravity concentration and sedimentation of the flocs. The upper part of the wastewater flows by gravity to the intermediate water tank for temporary storage. Then, the wastewater is lifted by the wastewater lifting device to the pulse water distributor, and then fed into the biological treatment unit for wastewater treatment. Microorganisms adsorb, oxidize, decompose and synthesize the organic pollutants in the wastewater to remove pollutants. The effluent from the biological treatment system meets the discharge standards.

[0038] The biochemical treatment unit adopts an anaerobic + aerobic treatment process or an anaerobic + anoxic + aerobic treatment process. The anaerobic treatment uses COD-reducing, highly efficient salt-tolerant bacteria, which is a mixture of Lactobacillus spp. (CICC 23053) and biological enzymes. After activating Lactobacillus spp., 6% wt Lactobacillus spp. solution and 5% biological enzymes are added to the wastewater.

[0039] The activation culture medium consists of 20.0 g / L glucose, 10.0 g / L yeast extract, 10.0 g / L peptone, 10.0 g / L sodium acetate, and 5.0 ml / L salt solution at pH 6.8. The salt solution formula is: 40.0 g / L MgSO4·7H2O, 2.0 g / L MnSO4·4H2O, 2.0 g / L FeSO4·7H2O, and 2.0 g / L NaCl.

[0040] The aerobic treatment employs self-acclimated salt-tolerant bacteria, which is a mixture of Bacillus circulatoryus (CICC 23053), Coxella roseum (CICC 20758), and biological enzymes. Bacillus circulatoryus and Coxella roseum are activated and acclimated separately. 6% wt Bacillus circulatoryus solution, 8% wt Coxella roseum solution, and 5% wt biological enzymes are added to the wastewater after acclimation.

[0041] In the aerobic treatment, the dissolved oxygen in the aerobic tank is controlled between 2 and 4 mg / L;

[0042] The activation medium consisted of 5.0 g / L peptone, 3.0 g / L beef extract, 5.0 g / L NaCl, 5 mg / L MnSO4·H2O, 15.0 g / L agar, and pH 7.0.

[0043] The acclimatization culture medium is composed of a mixture of phytic acid wastewater and heavy metal wastewater sterilized at high temperature, diluted with water to 50-60% of the original concentration, inoculated with 5% by volume of Bacillus circulatoryus and Coxella rosea after activation culture, and cultured at room temperature and 150-180 rpm for 60 days to obtain Bacillus circulatoryus acclimatization solution and Coxella rosea acclimatization solution, respectively.

[0044] The sludge from sedimentation tank 1, sedimentation tank 2, and the biochemical treatment unit is pumped out by a sludge discharge pump, dewatered by a plate and frame filter press, and then transported off-site.

[0045] like Figure 1 The diagram shows the synergistic treatment system for phytic acid wastewater and heavy metal wastewater, as well as the process flow chart.

[0046] Table 1 Wastewater Treatment Parameters

[0047]

[0048]

[0049] Table 2. Indicators of wastewater after mixing

[0050]

[0051] Table 3 Indicators after wastewater treatment

[0052]

[0053]

[0054] As can be seen from the above, the synergistic treatment process of phytic acid wastewater and heavy metal wastewater of the present invention improves the wastewater environment and reduces the content of COD, total phosphorus, and ammonia nitrogen. The mixing of phytic acid wastewater and heavy metal wastewater solves the problem of low C / N value in heavy metal wastewater. The high biodegradability of phytic acid wastewater improves the biodegradability of heavy metal wastewater and increases the B / C value in the wastewater. The lack of coagulants, flocculants, or the lack of anaerobic or aerobic treatment in the biological treatment unit all affect the treatment effect. It is evident that the synergistic treatment process of phytic acid wastewater and heavy metal wastewater described in the present invention has a significant treatment effect.

Claims

1. A synergistic treatment process for acidic wastewater and heavy metal wastewater, characterized in that, Includes the following steps: Heavy metal wastewater and phytic acid wastewater are added to the wastewater mixing reaction tank for mixing and reaction. The resulting wastewater mixture flows by gravity to the coagulation tank 1, where it forms large flocs. Then, it flows by gravity to the sedimentation tank 1 for mud-water separation. The resulting upper wastewater flows by gravity to the pH adjustment tank, and then flows to the multi-functional reaction tank, coagulation tank 2, and sedimentation tank 2 for mud-water separation. The upper wastewater flows by gravity to the intermediate water tank for temporary storage. Then, the wastewater is lifted by the wastewater lifting device to the pulse water distributor, and then fed into the biological treatment unit for wastewater treatment, so that the effluent meets the discharge standards. The gelation tank 1 is added with inorganic coagulant PAC and flocculant PAM, or the gelation tank 1 is added with iron salt and flocculant PAM. The gelation tank 2 is added with inorganic coagulant PAC and flocculant PAM, or iron salt and flocculant PAM are added to the gelation tank 2. The pH adjustment tank is used to adjust the pH of the wastewater to 7.5~12; The biochemical treatment unit adopts an anaerobic + aerobic treatment process or an anaerobic + anoxic + aerobic treatment process. The anaerobic treatment uses COD-reducing, highly efficient, salt-tolerant bacteria, which is a mixture of Bacillus sporogenes and biological enzymes. After activating Bacillus sporogenes, Bacillus sporogenes liquid and biological enzymes are added to the wastewater. The aerobic treatment employs self-acclimated salt-tolerant bacteria, which is a mixture of Bacillus circolithus, Coxella roseum, and biological enzymes. Bacillus circolithus and Coxella roseum are activated and acclimated separately, and the acclimated Bacillus circolithus, Coxella roseum, and biological enzymes are added to the wastewater.

2. The collaborative processing technology according to claim 1, characterized in that, The sludge from sedimentation tank 1, sedimentation tank 2, and the biochemical treatment unit is pumped out by a sludge discharge pump, dewatered by a plate and frame filter press, and then transported off-site.

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