Microflora for treating wastewater in food production process and treatment method

Abstract

The invention belongs to the field of water treatment, and particularly relates to a microbial community for treating wastewater in the food production process and a treatment method, and the microbial community comprises benthic diatom and symbiotic bacteria; wherein the benthic diatom is halaphalis coffeaeforms, and the symbiotic bacteria comprise a psychrobacter genus (Psychrobacter) and a halomonas genus (Halomonas), and the benthic diatom and the symbiotic bacteria can be used for preparing a biological agent for preventing and treating a disease caused by the fact that the benthic diatom and the symbiotic bacteria can be used for preventing and treating a disease caused by the disease caused by the fact that the benthic diatom is the Halomonas. According to the method, a one-step biological treatment method is adopted for the first time, no chemical reagent is used, nutrient elements are recycled in one step while waste water is recycled in the recycling process, and a new choice is provided for low-cost and sustainable waste water treatment.

Description

Technical Field

[0001] The invention belongs to the field of water treatment, and in particular relates to a microbial community for treating wastewater in a food production process and a treatment method. Background Art

[0002] At present, most of the wastewater from food production processes has the characteristics of high salinity (inorganic salt mass percentage concentration higher than 3.5wt%), low pH value, and rich nutrients, which need to be properly treated before discharge or recycling. Proper treatment using the facilities in traditional sewage treatment plants is extremely challenging, not only is it costly, but in most cases it also requires the consumption of large amounts of chemical reagents, and improper treatment can cause serious environmental damage.

[0003] In recent years, wastewater treatment based on microalgae biotechnology has provided a green and sustainable strategy for wastewater treatment due to its advantages in nutrient recovery, pollutant degradation and production of valuable biomass. The treated wastewater from food production processes can be recycled and reused. Some people have used green algae to treat wastewater, but green algae can only treat low-salinity wastewater with an inorganic salt content of less than 3.5wt%. When used directly to treat high-salinity wastewater, it will die or its growth will be extremely restricted because it cannot tolerate high salinity. High-salinity wastewater must be diluted into low-salinity wastewater before green algae can be used. In industrial operations, this dilution operation consumes a large amount of freshwater resources, resulting in an increase in wastewater treatment costs. In addition, dilution and various conventional water treatment technologies usually require multi-step treatment, and the process flow is too long. Some people have also used a diatom called "Triangular Brown Finger Algae" to successfully remove nutrients from urban sewage, but Triangular Brown Finger Algae is a suspended diatom that is suspended in the treated wastewater. In order to separate the wastewater from the diatom, high costs for algae separation (such as centrifugal separation or external flocculant sedimentation separation) will be incurred, which restricts the difficulty of its industrial promotion.

[0004] In addition, existing microalgae wastewater treatment processes are all aimed at removing total phosphorus, total nitrogen and nutrients in the water, but do not utilize phosphorus, nitrogen and nutrients as resources, and lack industrial added value. Summary of the invention

[0005] In order to solve at least one of the above problems, the technical solution of the present invention is proposed.

[0006] The preservation name of the microbial community of the present invention is: Halamphora coffeaeformis SZU-CQ, the preservation unit is: China Center for Type Culture Collection, and the preservation number is: CCTCC NO: M20231463.

[0007] A first aspect of the present invention provides a microbial community for treating wastewater from a food production process, wherein the microbial community comprises benthic diatoms and symbiotic bacteria; wherein the benthic diatoms are Halamphoracoffeaeformis, and the symbiotic bacteria comprise Psychrobacter and Halomonas.

[0008] Preferably, among the symbiotic bacteria, Psychrobacter accounts for 20-30% and Halomonas accounts for 20-30%.

[0009] The number of the Halamphobra coffeaeformis and the symbiotic bacteria is not limited to a certain ratio. After being inoculated in any ratio, the two algae can reproduce independently according to the abundance of their respective nutrients.

[0010] The second aspect of the present invention provides a method for treating wastewater from a high-salt and nutrient-rich food production process using Halamphoa coffeaeformis and symbiotic bacteria, wherein the high salt refers to an inorganic salt content higher than 3.5 wt %, and the nutrient-rich refers to a total nitrogen content greater than 100 mg / L and a total phosphorus content greater than 20 mg / L, and the method comprises the following treatment steps:

[0011] (1) Filter wastewater from food production processes to remove insoluble or suspended matter;

[0012] (2) Inoculating the filtrate obtained in the above step (1) with Halamphora coffeaeformis and symbiotic bacteria; preferably, the initial inoculation amount is calculated based on a chlorophyll a concentration of 1 mg / L in the wastewater after Halamphora coffeaeformis inoculation.

[0013] (3) Treat the wastewater for 4-14 days while introducing air into the wastewater, with the wastewater concentration varying from 50 to 100 μmol·m -2 ·s -1 The light intensity was irradiated for 12-18 hours, and then kept in a dark environment for 6-12 hours; the air temperature was 23±4°C.

[0014] Preferably, step (3) further includes a self-flocculation step, wherein the self-flocculation refers to the spontaneous flocculation of the microbial community in the water body without the need for adding an external flocculant.

[0015] Preferably, the process does not require nitrification and denitrification steps.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The existing high-salinity food production process wastewater treatment mostly adopts the method of first diluting the process wastewater and then treating it in a graded manner. The present invention adopts a "one-step" biological treatment method for the first time, without using any chemical reagents. While recycling the process wastewater for reuse, it also realizes the recovery of nutrients in "one step", providing a new option for achieving low-cost and sustainable wastewater treatment.

[0018] 2. Unlike other microorganisms that are difficult to survive in high-salt, low-pH, and nutrient-rich food production process wastewater, the benthic diatoms and symbiotic bacteria used in the present invention can quickly adapt to the high-salt, low-pH, and nutrient-rich food production process wastewater environment, and after treatment, the nutrients (N, P, and TOC) in the wastewater can be converted into potential raw materials for carotenoids (fucoxanthin), and can also be used as fertilizers, thereby increasing the economic added value of the wastewater treatment process.

[0019] 3. Wastewater treatment based on microalgae has always been limited by the expensive algae separation process required after treatment. The present invention unexpectedly discovered that the microbial community composed of benthic diatoms and symbiotic bacteria has a good self-sedimentation effect. After the wastewater treatment of the high-salinity food production process is completed, the wastewater and the microbial community can be separated by simple filtration, which can significantly reduce the overall cost and increase the feasibility of large-scale implementation.

[0020] 4. Existing microorganisms treat various forms of nitrogen in sewage mainly through nitrification and denitrification, which eventually converts soluble nitrogen into gaseous nitrogen for release, resulting in a waste of nutrients. The present invention can effectively convert total nitrogen into high value-added products such as fucoxanthin, and at the same time achieve a COD reduction of more than 98%. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with the embodiments.

[0022] Example 1

[0023] This example provides a method for treating high-salt and nutrient-rich mustard tuber production process wastewater by the microbial community of the present invention, wherein the chlorophyll a concentration in the wastewater after inoculation is 1 mg / L as the initial inoculation amount, and the specific water quality indicators of the wastewater from the production process of a certain brand of mustard tuber are obtained through sampling and measurement, as shown in Table 1 below:

[0024] Table 1 Specific water quality indicators of the wastewater from the production process of a certain brand of mustard tuber

[0025]

[0026] (1) filtering the mustard tuber wastewater stock solution through a 100-mesh standard sieve, and taking the filtrate for later use;

[0027] (2) taking 500 ml of the filtrate obtained in step (1) above, inoculating Halamphobra coffeaeformis SZU-CQ into the filtrate to achieve a chlorophyll a concentration of 1 mg / L after inoculation;

[0028] (3) The wastewater to be treated obtained in step (2) is subjected to a light intensity of 100 μmol·m -2 ·s -1 , light exposure for 16 hours, and then keep in a dark environment for 8 hours, during which air is introduced throughout the process, the air temperature is 23°C, and the air inlet is filtered using a 0.22μm PES green membrane;

[0029] (4) Repeat the above step (3) for 14 days to complete the treatment through self-flocculation.

[0030] The filtrate in step (4) was taken and the ammonia nitrogen, nitrate nitrogen, total nitrogen, total phosphorus, total organic carbon and total phosphorus were measured using the national standard method to evaluate the restoration performance (Ministry of Ecology and Environment of the People's Republic of China, 2002). The specific results are shown in 2 below:

[0031] Table 2 Statistics of wastewater remediation performance after inoculation with Halamphobra coffeaeformis SZU-CQ

[0032]

[0033] It can be seen that total nitrogen, total phosphorus and total organic matter have all been significantly reduced.

[0034] After 14 days of collection and treatment in the above step (4), the filter residue was obtained, and the maximum biomass concentration reached 1.74 g / L. With the assistance of glass beads, the pigment was extracted by vortexing with methanol for 10 minutes. The chlorophyll a concentration was calculated by reading the absorbance at 666 nm and 653 nm using a spectrophotometer sample, and the fucoxanthin was quantitatively quantified using HPLC equipped with a reverse phase column. The final results are shown in Table 3 below:

[0035] Table 3 Maximum biomass and fucoxanthin quantification of inoculated Halamphobra coffeaeformis SZU-CQ

[0036]

[0037] Comparative Example 1

[0038] This comparative example is different from Example 1 in that the mustard tuber production process wastewater stock solution used does not contain total organic carbon (TOC). After the microbial community Halamphora coffeaeformis SZU-CQ is inoculated in 500 ml of the above-mentioned mustard tuber production process wastewater from which total organic carbon (TOC) has been removed, due to the lack of total organic carbon (TOC), the symbiotic bacteria cannot grow, and only the marine double eyebrow algae (Halamphora coffeaeformis) is reproduced in this comparative example. The filtrate is measured for ammonia nitrogen, nitrate nitrogen, total nitrogen, total organic carbon and total phosphorus using the national standard method to evaluate the restoration performance (Ministry of Ecology and Environment of the People's Republic of China, 2002), and the specific results are shown in Table 4 below:

[0039] Table 4 Statistics of remediation performance of wastewater inoculated with Halamphobra coffeaeformis

[0040]

[0041] As shown in the table, the effects of nutrient salt treatment were significantly lower than those in Implementation 1.

[0042] The maximum biomass concentration of the filter residue reached 1.02 g / L. With the help of glass beads, the pigment was extracted by vortexing with methanol for 10 minutes. The chlorophyll a concentration was calculated by reading the absorbance at 666 nm and 653 nm using a spectrophotometer. The fucoxanthin was quantitatively determined using HPLC equipped with a reverse phase column. The specific results are shown in Figure 5:

[0043] Table 5 Maximum biomass and quantification of fucoxanthin after inoculation of Halamphobra coffeaeformis

[0044]

[0045] Comparative Example 2

[0046] The difference between this comparative example and Example 1 is that after the microbial community Halamphora coffeaeformis SZU-CQ is inoculated into the wastewater of the mustard tuber production process, the light intensity in step (3) is adjusted to weak light (the weak light described here refers to a light intensity of less than 40 μmol·m-2·s-1). This example selects 20 μmol·m-2·s-1 for culturing. Under this culturing condition, the growth of Halamphora coffeaeformis is inhibited compared with that in Example 1, and only the symbiotic bacteria multiply in large quantities. The specific results are shown in Table 6 below:

[0047] Table 6 Statistics of remediation performance of wastewater inoculated with symbiotic bacteria

[0048]

[0049] The maximum biomass concentration of the filter residue reached 0.75 g / L. With the help of glass beads, the pigment was extracted with methanol by vortexing for 10 minutes. The chlorophyll a concentration was calculated by reading the absorbance at 666 nm and 653 nm using a spectrophotometer. The fucoxanthin was quantitatively determined using HPLC equipped with a reverse phase column. The specific results are shown in 7 below:

[0050] Table 7 Maximum biomass of inoculated symbiotic bacteria and quantification of fucoxanthin

[0051]

[0052] As shown in the table, the effects of nutrient salt treatment were significantly lower than those in Implementation 1.

[0053] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A microbial community for treating wastewater from a food production process, characterized in that: The microbial community comprises benthic diatoms and symbiotic bacteria; wherein the benthic diatoms are Halamphora coffeaeformis, and the symbiotic bacteria comprise Psychrobacter and Halomonas.

2. The microbial community according to claim 1, characterized in that Among the symbiotic bacteria, Psychrobacter accounts for 20-30% and Halomonas accounts for 20-30%.

3. A method for treating wastewater from a high-salt and nutrient-rich food production process using the microbial community of claim 1, wherein the high salt refers to an inorganic salt content higher than 3.5 wt%, and the nutrient-rich refers to a total nitrogen content greater than 100 mg / L and a total phosphorus content greater than 20 mg / L, characterized in that: The method comprises the following processing steps: (1) Filter wastewater from food production processes to remove insoluble or suspended matter; (2) inoculating the filtrate obtained in the above step (1) with the microbial community described in claim 1; (3) Treat the wastewater for 4-14 days while introducing air into the wastewater, with the wastewater concentration varying from 50 to 100 μmol·m -2 ·s -1 The light intensity was irradiated for 12-18 hours, and then kept in a dark environment for 6-12 hours; the air temperature was 23±4°C.

4. The method according to claim 3, characterized in that The step (3) also includes a self-flocculation step, wherein the self-flocculation means that the microbial community in the water body spontaneously flocculates without the need for adding an external flocculant.

5. The method according to claim 3, characterized in that The method does not require nitrification and denitrification steps.

Images