Domestication culture method of phycomycete system with high ammonia nitrogen tolerance

Abstract

The invention discloses a domestication culture method of a high-ammonia-nitrogen-tolerant phycomycete system, and relates to the technical field of resources and environments. Comprising the following steps: taking phycomycetes from a high-ammonia-nitrogen wastewater storage tank, inoculating a culture medium with the phycomycetes, and entering the next stage after outdoor culture reaches an evaluation standard I; illuminating the incubator indoors, keeping the TN concentration of the culture medium unchanged, adjusting the ratio of NH4 < + >-N / NO3 <->-N in a gradient manner, and entering the next gradient after each gradient reaches an evaluation standard II; when the culture medium TN is completely composed of NH4 < + >-N, entering the next stage; the NH4 < + >-N concentration of the culture medium is increased according to the gradient, the C and P concentrations are adjusted according to the C / N ratio and the N / P ratio, and after each gradient reaches the evaluation standard III or IV, the next gradient is started. The phycomycete system can treat high-ammonia-nitrogen wastewater, the nitrogen and phosphorus removal rate reaches 85% or above when the ammonia nitrogen concentration is 1500 mg / L or below, the total lipid content in recycled algae is larger than 30%, and the total protein content gt is obtained; the traditional denitrification cost is greatly reduced, and the efficiency of carbon, nitrogen and phosphorus resource recovery and carbon emission reduction of the system is remarkably improved.

Description

Technical Field

[0001] The invention relates to the field of resource and environmental technology, and in particular to a method for acclimating and cultivating a high ammonia nitrogen tolerant algae-bacteria system. Background Art

[0002] It is generally believed that wastewater with an ammonia nitrogen concentration higher than 500 mg / L is considered high ammonia nitrogen wastewater. This type of wastewater mainly comes from industries such as fertilizer production, livestock and poultry farming, food processing and fermentation. Due to its numerous pollution sources, high emission concentration and large water volume, it has always attracted much attention and research. At present, the mainstream high ammonia nitrogen wastewater treatment processes include physical and chemical methods and biological methods. Physical and chemical methods, such as air stripping, adsorption or breakpoint chlorination, have the advantages of simple process and easy operation, but their applicability is relatively narrow, and most methods are expensive. The biological method is to convert ammonia nitrogen into nitrogen gas through a series of reactions such as nitrification, denitrification or anaerobic ammonia oxidation. This method is environmentally friendly and low-cost. However, high concentrations of ammonia nitrogen are prone to produce free ammonia. If the system is not properly controlled, it will inhibit most bacteria and lead to a waste of nitrogen resources.

[0003] Microalgae refer to tiny algae groups whose morphology can only be identified under a microscope. They can convert inorganic nutrients such as carbon, nitrogen, and phosphorus into their own organic matter through photosynthesis, thereby achieving growth. After recovery, algae can be used to produce biodiesel, feed protein, etc., and have been widely studied and applied in recent years. Existing domestic and foreign research and public information show that algae purchased directly from algae seed banks or microbial strain preservation and management centers can only tolerate ammonia nitrogen concentrations of up to 300-500 mg / L after domestication and cultivation. The separation and culture method can separate a single pure algae from the target water body or natural water body, but this method can only achieve the treatment of high ammonia nitrogen wastewater under sterilization conditions. At present, there is no method for treating high ammonia nitrogen wastewater by domesticating and culturing an algae-bacteria mixed system. Summary of the invention

[0004] The purpose of the present invention is to provide a method for acclimating and cultivating a high ammonia nitrogen tolerant algae-bacteria system, which helps to transform the traditional wastewater "Energy negative" treatment mode into an "Energy positive" mode, while achieving the coordinated treatment of carbon, nitrogen and phosphorus, and realizing the recovery and utilization of resources.

[0005] To achieve the above objectives, the technical solution of the present application is: a method for acclimating and cultivating a high ammonia nitrogen tolerant algae-bacteria system, comprising:

[0006] Take algae and fungi from the high-ammonia nitrogen wastewater storage tank and inoculate them into the culture medium. After the algae and fungi are cultivated outdoors and reach the evaluation standard I, they will enter the next stage.

[0007] In an indoor light incubator, keep the TN concentration of the culture medium constant and adjust the NH4 + -N / NO 3- -N ratio, each gradient reaches the evaluation standard II and enters the next gradient; when the culture medium TN is completely NH4 + -N is formed and enters the next stage;

[0008] Increase the NH4 content of the culture medium according to the gradient + -N concentration, and adjust the C and P concentrations according to the C / N ratio and N / P ratio. Each gradient enters the next gradient after reaching the evaluation standard III or IV.

[0009] As a preferred embodiment of the present invention, the evaluation criteria I, II, III and IV are respectively:

[0010]

[0011] As a preferred embodiment of the present invention, the high ammonia nitrogen wastewater storage tank is open-air, the TN concentration range is 300-1500 mg / L, and the average low temperature is greater than 10°C.

[0012] As a preferred embodiment of the present invention, the depths of algae and fungi taken from the high ammonia nitrogen wastewater storage tank from the liquid surface are 10-20 cm (30-70% volume), 30-50 cm (10-30% volume) and 80-100 cm (5-20% volume).

[0013] As a preferred embodiment of the present invention, the culture medium comprises the following components: CO 3- 500-2000mg / L, NO3 - -N250-500mg / L, PO4 3- -P 50mg / L, CaCl2·2H2O50mg / L, MgSO4100 mg / L, citric acid 10mg / L, ammonium ferric citrate 10mg / L, EDTA2Na 1mg / L.

[0014] As a preferred embodiment of the present invention, the inoculation amount of the algae and fungi inoculated into the culture medium is 10% to 20%.

[0015] As a preferred embodiment of the present invention, the gradient adjustment of NH4 + -N / NO 3- The -N ratios are 0.3:1, 1:1, 1:0.3 and 1:0.

[0016] As a preferred embodiment of the present invention, the NH4 content of the culture medium is increased in a gradient of 300-500 mg / L. + -N concentration, and adjust the C and P concentrations according to a C / N ratio of 1-5:1 and a N / P ratio of 5-10:1.

[0017] By adopting the above technical scheme, the present invention can achieve the following technical effects: the algae-bacteria system can treat high ammonia nitrogen wastewater, and the nitrogen and phosphorus removal rate reaches more than 85% when the ammonia nitrogen concentration is below 1500 mg / L, the total lipid content in the recovered algae is greater than 30%, and the total protein content is greater than 35%, which greatly reduces the traditional denitrification cost and significantly improves the system's carbon, nitrogen and phosphorus resource recovery and carbon emission reduction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 This is a schematic diagram of TN removal rate and biomass changes in outdoor cultivation in Example 1;

[0020] Figure 2 This is a schematic diagram of the TN removal rate and biomass change in the incubator in Example 1;

[0021] Figure 3 This is a schematic diagram of TN removal rate and biomass changes after the culture medium concentration is increased in Example 1;

[0022] Figure 4 Schematic diagram of TN removal rate and biomass change in Comparative Example 1;

[0023] Figure 5 Schematic diagram of TN removal rate and biomass changes in Comparative Example 2. DETAILED DESCRIPTION

[0024] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0025] Example 1: Take inoculum from an open-air digestion liquid storage tank of a pig farm in Hainan. The average low temperature during sampling reaches 15°C. The TN concentration of the digestion liquid is 430 mg / L. The sampling volume ratio is 3L at 20cm from the liquid surface, 1.8L at 50cm, and 1.2L at 100cm. Mail it to the laboratory. Use NaCO3, NaNO3, KH2PO4 and other nutrient salts to prepare the culture medium and control the CO3 in the culture medium. - 1000mg / L, NO3 - -N 500mg / L, PO4 3--P 50mg / L, CaCl2·2H2O 50mg / L, MgSO4100 mg / L, citric acid 10mg / L, ammonium ferric citrate 10mg / L, EDTA2Na 1mg / L. Inoculate the inoculum into the prepared culture medium at a 15% inoculation rate, such as Figure 1 As shown, after 15 days of outdoor cultivation, the system entered the next stage after the TN removal rate reached 50% and the biomass reached 620 mg / L.

[0026] The conditions of the controlled light incubator are: light intensity of 2780 lux, temperature of 27°C, humidity of 60% RH, and light-dark ratio of 12:12h. Figure 2 As shown, adjust the medium NH4 + -N / NO3 - -N ratio was 0.3:1, and after 12 days, the TN removal rate reached 80.51% and the biomass reached 1628.38 mg / L; continue to adjust NH4 + -N / NO3 - -N ratio was 1:1, and after 12 days, the TN removal rate reached 84.9% and the biomass reached 2829.29 mg / L; continue to adjust NH4 + -N / NO 3- -N ratio was 1:0.3, and after 12 days, the TN removal rate reached 90.87% and the biomass reached 3568.28 mg / L; continue to adjust NH4 + -N / NO3 - -N ratio was 1:0, and after 12 days, the TN removal rate reached 94.54% and the biomass reached 5427.7 mg / L.

[0027] from Figure 3 It can be seen that when the TN concentration of the culture medium is increased to 1000 mg / L, CO3 - The concentration increased to 1200mg / L, PO4 3- When the concentration was increased to 150 mg / L, the TN removal rate reached 80%, the biomass reached 5200 mg / L, and the chlorophyll reached 3.01 mg / g after 14 days; when the TN concentration of the high culture medium was increased to 1500 mg / L, CO3 - The concentration increased to 2000mg / L, PO4 3- The concentration was increased to 200 mg / L. After 12 days, the TN removal rate reached 75%, the biomass reached 4500 mg / L, and the chlorophyll reached 2.95 mg / g. When the TN concentration of the culture medium was increased to 2000 mg / L, CO3 - The concentration increased to 2500mg / L, PO4 3-When the concentration was increased to 300 mg / L, the TN removal rate reached 50%, the biomass was stabilized at 4000 mg / L, and the chlorophyll reached 2.65 mg / g; when the TN concentration of the culture medium was increased to 2500 mg / L, CO3 - The concentration increased to 3000mg / L, PO4 3- The concentration was increased to 400 mg / L, but the algae-bacteria system could no longer grow normally. After two cultivations, each index could not meet the evaluation criteria III or IV, indicating that the algae-bacteria system reached the highest ammonia nitrogen tolerance concentration under the condition of TN of 2000 mg / L, and the acclimation culture was completed.

[0028] Comparative Example 1: A traditional method was used to acclimate and culture a high ammonia nitrogen tolerant bacteria and algae system. The algae species used was Chlorella sp. (No. FACHB-31), which has been shown to have high ammonia nitrogen tolerance within a certain range. The initial inoculation amount of Chlorella sp. was 500 mg / L, which was inoculated into the prepared culture medium. The nutrients in the culture medium were consistent with those in the embodiment, including CO 3- 1000mg / L, NO3 - -N 500mg / L, PO4 3- -P 50mg / L, CaCl2·2H2O 50mg / L, MgSO4 100 mg / L, citric acid 10mg / L, ammonium ferric citrate 10mg / L, EDTA2Na 1mg / L. Chlorella was directly cultured in a light incubator, and the culture conditions were consistent with those in the embodiment, i.e., the light intensity was 2780lux, the temperature was 27°C, the humidity was 60%RH, the light-dark ratio was 12:12h, and concentration gradient acclimation was started after the logarithmic growth period.

[0029] Since the algae grow in a suspended state, first centrifuge at 4000 rpm for 10 min, collect the initial Chlorella that has grown to the logarithmic phase, and inoculate it with NH4 + -N concentrations were 125mg / L, 250mg / L, and 500mg / L culture medium for acclimatization. Figure 4 As shown in the figure, after 10 days of cultivation, the total nitrogen removal rates reached 48.8%, 40.11%, and 37.26%, respectively, and the biomass reached 158.46 mg / L, 100.23 mg / L, and 37.09 mg / L, respectively. Even at an ammonia nitrogen concentration of 125 mg / L, the removal rate was still at a low level, and the various indicators could not meet the evaluation standard I. Moreover, as the concentration increased, the total nitrogen removal rate and biomass showed a significant downward trend, indicating that it is not feasible to directly carry out high ammonia nitrogen tolerance domestication of algae under the same initial conditions of domestication.

[0030] Comparative Example 2: Inoculum was taken from an open-air digestion liquid storage tank of a pig farm in Hainan. The average low temperature during sampling reached 15°C, the TN concentration of the digestion liquid was 430 mg / L, and the sampling volume ratio was 3L at 20cm from the liquid surface, 1.8L at 50cm, and 1.2L at 100cm. It was mailed to the laboratory. The culture medium was prepared using nutrient salts such as NaCO3, NH4Cl, and KH2PO4, and 20% of the inoculum was inoculated into NH4 + -N was used in a culture medium with 500mg / L and 1000mg / L, and the culture medium was prepared with nutrients such as NaCO3 and KH2PO4. The culture was placed in a light incubator for cultivation, and the conditions of the light incubator were controlled as follows: light intensity of 2780lux, temperature of 27℃, humidity of 60%RH, and light-dark ratio of 12:12h.

[0031] like Figure 5 As shown, after 16 days of cultivation, NH4 + In the medium with 500 mg / L of NH4, the removal rate and biomass were 29.66% and 505.42 mg / L respectively; + In the medium with -N of 1000 mg / L, the removal rate and biomass were 16.75% and 450.78 mg / L, respectively. Both met the requirements of evaluation standard I, and the domestication of the algae-bacteria system failed.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for acclimating and cultivating a high ammonia nitrogen tolerant algae-bacteria system, characterized in that: include: Take algae and fungi from the high-ammonia nitrogen wastewater storage tank and inoculate them into the culture medium. After the algae and fungi are cultivated outdoors and reach the evaluation standard I, they will enter the next stage. In an indoor light incubator, keep the TN concentration of the culture medium constant and adjust the NH4 + -N / NO 3- -N ratio, each gradient reaches the evaluation standard II and enters the next gradient; when the culture medium TN is completely NH4 + -N is formed and enters the next stage; Increase the NH4 content of the culture medium according to the gradient + -N concentration, and adjust the C and P concentrations according to the C / N ratio and N / P ratio. Each gradient enters the next gradient after reaching the evaluation standard III or IV.

2. The method for acclimating and cultivating a high ammonia nitrogen tolerant algae-bacteria system according to claim 1, characterized in that: The evaluation standard I is TN removal rate > 50%, biomass > 500 mg / L; the evaluation standard II is TN removal rate > 80%, biomass > 1500 mg / L; the evaluation standard III is TN removal rate > 80%, biomass > 5000 mg / L; the evaluation standard IV is TN removal rate > 65%, biomass > 3000 mg / L, chlorophyll > 2.0 mg / g.

3. The method for acclimating and cultivating a high ammonia nitrogen tolerant algae-bacteria system according to claim 1, characterized in that: The high ammonia nitrogen wastewater storage tank is open-air, with a TN concentration range of 300 to 1500 mg / L and an average low temperature of >10°C.

4. The method for acclimating and cultivating a high ammonia nitrogen tolerant algae-bacteria system according to claim 1, characterized in that: The depths of algae and fungi taken from high ammonia nitrogen wastewater storage tanks from the liquid surface were 10-20cm, 30-50cm and 80-100cm respectively.

5. The method for acclimating and cultivating a high ammonia nitrogen tolerant algae-bacteria system according to claim 1, characterized in that: The culture medium comprises the following components: CO3 - 500-2000mg / L, NO3 - -N250-500mg / L, PO4 3- -P 50mg / L, CaCl2·2H2O50mg / L, MgSO4100mg / L, citric acid 10mg / L, ammonium ferric citrate 10mg / L, EDTA2Na 1mg / L.

6. The method for acclimating and cultivating a high ammonia nitrogen tolerant algae-bacteria system according to claim 1, characterized in that: The inoculation amount of algae and fungi inoculated into the culture medium is 10% to 20%.

7. The method for acclimating and cultivating a high ammonia nitrogen tolerant algae-bacteria system according to claim 1, characterized in that: The gradient adjusts NH4 + -N / NO 3- The -N ratios are 0.3:1, 1:1, 1:0.3 and 1:

0.

8. The method for acclimating and cultivating a high ammonia nitrogen tolerant algae-bacteria system according to claim 1, characterized in that: Increase the NH4 content of the culture medium in a gradient of 300-500 mg / L + -N concentration, and adjust the C and P concentrations according to a C / N ratio of 1-5:1 and a N / P ratio of 5-10:1.

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