Method for treating Maotai-flavor liquor wastewater by using bacteria and algae and application of wastewater treated by method

Abstract

The invention discloses a method for treating Maotai-flavor liquor wastewater by using bacteria and algae, and belongs to the technical field of liquor wastewater treatment and application. The method comprises the following steps: S1, pretreating liquor wastewater to remove part of suspended solids and part of COD (Chemical Oxygen Demand); s2, the pretreated wastewater is inoculated with chlorella pyrenoidosa with the concentration of 1-1.5 * 10 < 6 > cells / mL and rhodopseudomonas palustris with the concentration of 2-2.5 * 10 < 4 > spores / mL, and the treatment time is 7-10 days. According to the application, the chlorella pyrenoidosa and the rhodopseudomonas palustris act synergistically to treat the liquor wastewater, and the COD removal rate and the chroma elimination rate are synchronously increased through metabolism complementation and synergistic effects.

Description

Technical Field

[0001] The present invention relates to the technical field of liquor wastewater treatment and application, and particularly relates to a method for treating Maotai-flavor liquor wastewater by using bacteria and algae and the application of the treated wastewater. Background Art

[0002] The wastewater from Maotai-flavor liquor mainly comes from production links such as grain moistening, stacking fermentation, pit entry fermentation, distillation, and pit mud treatment. These wastewaters are characterized by high concentrations of organic matter, microorganisms, alcohol, high chromaticity, and other impurities. If directly discharged without treatment, it will cause eutrophication of water bodies, affect water quality, and even damage the aquatic ecosystem; especially when the high chromaticity of the wastewater is directly discharged into the water body without treatment or with unqualified treatment, it will significantly reduce the transparency of the water body. The reduction of water body transparency will affect the photosynthesis of aquatic plants, and thus have a negative impact on the entire aquatic ecosystem.

[0003] With the tightening of environmental protection policies, liquor manufacturing enterprises need to take measures to significantly reduce the chemical oxygen demand in the wastewater before discharging it into the sewage treatment plant. Traditional treatment methods use the following process: "a combined process of pretreatment + high-efficiency anaerobic reactor + multi-stage AO~DIAB~MBR + advanced oxidation + membrane treatment". Although these methods can remove a certain amount of chromaticity, they have problems such as low COD removal rate, low light energy transfer efficiency, and membrane fouling, and a large number of devices need to be used, such as anaerobic reactors, membrane-biological reactor processors, etc. These devices have large investments and are not conducive to popularization. Therefore, it is of great significance to develop a highly efficient and low-cost method for chromaticity elimination and resource utilization. Summary of the Invention

[0004] The present invention aims to provide a method for treating Maotai-flavor liquor wastewater by using bacteria and algae and the application of the treated wastewater, which is a highly efficient and environmentally friendly method for eliminating the chromaticity of Maotai-flavor liquor wastewater, and converting it into a culture medium suitable for microalgae cultivation to achieve the resource utilization of the wastewater.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for treating Maotai-flavor liquor wastewater by using bacteria and algae, comprising the following steps:

[0007] S1. Pretreat the liquor wastewater to remove part of the suspended solids and part of the COD;

[0008] S2. Inoculate the pretreated wastewater with Chlorella pyrenoidosa and Rhodopseudomonas palustris, and the treatment time is 7-10 d.

[0009] In some embodiments, after the wastewater is inoculated, the concentration of Chlorella pyrenoidosa in the wastewater is 1-1.5×10 6cells / mL, the concentration of Rhodopseudomonas palustris is 2 - 2.5×10 4 spores / mL.

[0010] In some embodiments, the pretreatment adopts mechanical separation and coagulation - flotation methods.

[0011] In some embodiments, the mechanical separation method uses screen filtration, the screen aperture is 1 - 2 mm, and the filtration speed is 0.5 - 1 m 3 / h; in the coagulation - flotation method, the dosage of the coagulant is 100 - 200 mg / L, and the residence time in the flotation tank is 20 - 30 min.

[0012] In some embodiments, it further includes advanced treatment, adopting Fenton oxidation and activated carbon adsorption.

[0013] In some embodiments, the process conditions of the Fenton oxidation are pH value 3.5, the amount of H2O2 is 400 mg / L, the amount of FeSO4 is 600 mg / L, and the reaction time is 60 minutes; the process conditions of the activated carbon adsorption are pH value 5, temperature 30 °C, dosage 1.5 g / L, and adsorption time 30 minutes.

[0014] An application of the treated wastewater, which is used in the preparation of a microalgae culture medium.

[0015] In some embodiments, the treated wastewater is used as a culture medium for microalgae, and open - type cultivation is carried out using a raceway pond.

[0016] In some embodiments, urea is added to the culture medium to make the nitrogen content reach 100 - 150 mg / L, and potassium dihydrogen phosphate is added to make the phosphorus content reach 10 - 20 mg / L; the culture conditions are pH value 6.5 - 7.5, temperature 25 - 30 °C, light intensity 1000 - 10000 lx, and culture time 10 - 15 days.

[0017] The working principle and beneficial effects of the present invention:

[0018] (1) In the prior art, microalgae (such as Chlorella) or fungi (such as Rhodopseudomonas palustris) are often used alone for wastewater treatment, but the systematic application of their synergistic effect has not been reported. By optimizing the inoculation ratio, through metabolic complementarity and synergistic effect, the COD removal rate and chromaticity elimination rate are simultaneously improved.

[0019] (2) The traditional process aims at reaching the discharge standard and does not consider the high - value utilization of wastewater. The treated wastewater is directly converted into a microalgae culture medium, combined with an open - type cultivation system (raceway pond), to achieve the dual goals of "treating waste with waste" and "resource regeneration". The integration of this process chain (pretreatment → bacteria - algae treatment → microalgae cultivation → advanced treatment → biomass utilization) is the first in the field of liquor wastewater.

[0020] (3) Although Fenton oxidation and activated carbon adsorption are conventional technologies, in view of the high chromaticity and high COD characteristics of Baijiu wastewater, the present application significantly improves the efficiency through parameter optimization (such as the ratio of H2O2 / Fe 2+ ratio and the dosage of activated carbon).

[0021] In summary, the present application solves the problem of treating Maotai-flavor Baijiu wastewater, avoiding the visual pollution and ecological toxicity of high-chromaticity wastewater to water bodies; reducing the use of chemical agents (such as a large amount of oxidants required for traditional decolorization), reducing the risk of secondary pollution; promoting the transformation of the brewing industry to a circular economy model, in line with the "dual-carbon" strategic goal. Moreover, the treatment is efficient and low-cost. Specific Embodiments

[0022] The following is a further detailed description through specific embodiments:

[0023] A method for treating Maotai-flavor Baijiu wastewater using bacteria and algae includes the following steps:

[0024] S1. Pretreat the Baijiu wastewater to remove part of the suspended solids and part of the COD. The pretreatment adopts mechanical separation and coagulation-flotation methods.

[0025] S2. Inoculate the pretreated wastewater with Chlorella pyrenoidosa and Rhodopseudomonas palustris, and the treatment time is 7-10 days. The concentration of Chlorella pyrenoidosa is 1-1.5×10 6 cells / mL, and the concentration of Rhodopseudomonas palustris is 2-2.5×10 4 spores / mL.

[0026] I. Verification of the bacteria-algae co-treatment system The following experiments were designed:

[0027] Experimental materials and equipment Wastewater source: Maotai-flavor Baijiu production wastewater (COD 5000-6000 mg / L, chromaticity 800-1000 times, TN 150-200 mg / L, TP 30-50 mg / L); Microbial strains: Chlorella pyrenoidosa, Rhodopseudomonas palustris; Culture medium additives: urea, potassium dihydrogen phosphate, FeCl3, Al2(SO4)3; Equipment: coagulation-flotation tank, raceway pond culture system, Fenton reactor, activated carbon adsorption column, spectrophotometer, COD analyzer, centrifuge.

[0028] Control group 1: Only Chlorella pyrenoidosa (inoculation concentration 1×10 6 cells / mL). Control group 2: Only Rhodopseudomonas palustris (inoculation concentration 2×10 4spores / mL). Experimental group: Chlorella pyrenoidosa (inoculation concentration 1×10 6 cells / mL), Rhodopseudomonas palustris (inoculation concentration 2×10 4 spores / mL), combined bacteria and algae (ratio 1:5000).

[0029] Pretreated wastewater: mechanical screen filtration (1 mm pore size) + coagulation flotation (FeCl3 150 mg / L). Different strains were inoculated respectively and placed in a constant temperature shaker (25 °C, light intensity 2000 lx, rotation speed 120 rpm). Samples were taken every 24 hours to measure COD, chromaticity, TN, TP and dissolved oxygen (DO). Treatment cycle: 7 days. The data in Table 1 were obtained:

[0030] Table 1

[0031]

[0032]

[0033] It can be seen from the data in Table 1 that the combined bacteria and algae treatment significantly improved the pollutant removal efficiency (COD ↑ 24.5%, chromaticity ↑ 44.7%), proving the existence of synergistic effect.

[0034] II. Verification of the effectiveness of the treated wastewater as a microalgae culture medium

[0035] The wastewater treated by bacteria and algae (COD reduced to 800 mg / L) was used as the basal medium; urea (N 120 mg / L) and potassium dihydrogen phosphate (P 15 mg / L) were added, and the pH was adjusted to 7.0; Spirulina was inoculated, and the initial biomass of Spirulina was 0.1 g / L. It was placed in a raceway pond (depth 0.3 m, light intensity 5000 lx, temperature 28 °C); the microalgae biomass (dry weight method), COD, TN and TP were monitored daily. The data in Table 2 were obtained:

[0036] Table 2

[0037] Cultivation time (days) Microalgae biomass (g / L) COD (mg / L) TN (mg / L) TP (mg / L) 0 0.10 800 120 15 5 1.80 380 50 6 10 3.20 120 20 3 15 4.10 40 8 1

[0038] Table 2 shows that Spirulina showed higher biomass accumulation (4.1 g / L) in the wastewater culture medium, and the pollutant removal rates were better (COD 95%, TN 93.3%, TP 93.3%).

[0039] III. Verification of the optimization of the advanced treatment process

[0040] Verify the removal effect of Fenton oxidation and activated carbon adsorption on residual COD. Take the effluent after microalgae cultivation (COD 75 mg / L), adjust the pH to 3.5. Add H2O2 (400 mg / L) and FeSO4 (600 mg / L), and react for 60 minutes. After filtration, pass through an activated carbon column (dosage 1.5 g / L, contact time 30 minutes), and measure the COD of the final effluent. The data in Table 3 are obtained as follows:

[0041] Table 3

[0042] Treatment stage COD (mg / L) Removal rate (%) Effluent from microalgae cultivation 75 - After Fenton oxidation 14 81.3 After activated carbon adsorption 8 94.7

[0043] From the data in Table 3, it can be seen that after advanced treatment, the COD drops to 8 mg / L, far lower than the national standard (the limit of GB 27631-2011 is 100 mg / L).

[0044] In summary, the bacteria-algae synergistic effect: the combined treatment significantly improves the COD removal rate (81.3% vs 65.2% / 52.8% alone) and the chromaticity removal rate (73.2% vs 28.5% / 45.6% alone). The wastewater is successfully converted into a microalgae culture medium, the biomass reaches 2.8 g / L, and the pollutant removal rate is >85%. The goal of "treating waste with waste" is achieved, realizing efficient and low-cost wastewater treatment and resource utilization.

Claims

1. A method for treating Maotai-flavor liquor wastewater using bacteria and algae, characterized in that: include: S1. Pre-treat liquor wastewater to remove part of suspended solids and part of COD; S2. The pretreated wastewater is inoculated with Chlorella pyrenoidosa and Rhodopseudomonas palustris for 7 to 10 days.

2. The method for treating Maotai-flavor liquor wastewater using bacteria and algae according to claim 1, characterized in that: After the wastewater is inoculated, the concentration of Chlorella pyrenoidosa in the wastewater is 1 to 1.5×10 6 cells / mL, and the concentration of Rhodopseudomonas palustris was 2-2.5×10 4 spores / mL.

3. The method for treating Maotai-flavor liquor wastewater using bacteria and algae according to claim 2, characterized in that: The pretreatment adopts mechanical separation method and coagulation-flotation method.

4. The method for treating Maotai-flavor liquor wastewater using bacteria and algae according to claim 3, characterized in that: The mechanical separation method adopts screen filtration, the screen aperture is 1-2 mm, and the filtration speed is 0.5-1 m 3 / h; the dosage of coagulant in the coagulation flotation method is 100-200 mg / L, and the residence time in the flotation tank is 20-30 min.

5. The method for treating Maotai-flavor liquor wastewater using bacteria and algae according to claim 4, characterized in that: It also includes advanced treatment using Fenton oxidation and activated carbon adsorption.

6. The use of the treated wastewater according to claim 5, characterized in that: The process conditions of Fenton oxidation are pH 3.5, H2O2 amount 400 mg / L, FeSO4 amount 600 mg / L, and reaction time 60 minutes; the process conditions of activated carbon adsorption are pH 5, temperature 30°C, dosage 1.5 g / L, and adsorption time 30 minutes.

7. An application of treated wastewater, comprising the use of the treated wastewater according to any one of claims 1 to 6 in preparing a microalgae culture medium.

8. The use of the treated wastewater according to claim 7, characterized in that: The treated wastewater is used as a culture medium for microalgae and open culture is carried out in a raceway pond.

9. The use of the treated wastewater according to claim 8, characterized in that: Urea is added to the culture medium so that the nitrogen content reaches 100-150 mg / L, and potassium dihydrogen phosphate is added so that the phosphorus content reaches 10-20 mg / L; the culture conditions are pH 6.5-7.5, temperature 25-30°C, light intensity 1000-10000lx, and the culture time is 10-15 days.

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