CN105505779A - Resource utilization method of livestock excrement water-soluble manure production wastewater for culturing dunaliella - Google Patents

Abstract

The invention belongs to the field of wastewater treatment, and provides a resource utilization method of livestock excrement water-soluble manure production wastewater for culturing dunaliella. The method comprises the following steps: 1) diluting livestock excrement water-soluble manure production wastewater with water, 2) adding nutrient elements like P, Ca, Fe and Mg into the diluted livestock excrement water-soluble manure production wastewater, 3) using one or more of a NaCl solution, seawater and brine to adjust the salinity value of the wastewater to be 150-200, and controlling the pH value to be 8.0-9.0, (4) vaccinating dunaliella in the logarithmic growth phase for culture, and 5) continuously culturing for 8-12 d so as to obtain dunaliella after dunaliella grows to be in the platform phase. According to the provided method, treatment of the livestock excrement water-soluble manure production wastewater and recycle of the nutrient elements are combined, pollutants in the wastewater can be desorbed, biomass raw materials can be produced, and multiple efficacies of environmental protection, cost saving, resource recycle and nutrient element cyclic utilization are played.

Description

A resource utilization method for cultivating Dunaliella in livestock and poultry manure water-soluble fertilizer production wastewater

technical field

The invention belongs to the field of waste water treatment, and in particular relates to a waste water treatment method using microorganisms.

Background technique

Livestock and poultry biogas slurry is the residual liquid after anaerobic fermentation of farm manure, which belongs to high-concentration organic wastewater, which contains soluble substances such as ammonium salt, potassium salt, and phosphate salt. N, P, K and other nutrients in biogas slurry. The biogas slurry can be used as organic fertilizer and applied to the land to create more economic value. The biogas slurry produced abroad is usually consumed by the supporting land, but due to the excessive and concentrated biogas slurry output in China, biogas producers do not have enough land for consumption. If a large amount of biogas slurry is not disposed of, it is not only a waste of resources, but also a huge pressure on the soil, water and other environments.

Nowadays, the use of membrane filtration system to treat biogas slurry has received a lot of attention and application. The biogas slurry is concentrated by membrane filtration to form a concentrate and a supernatant. The concentrated liquid can be used as water-soluble fertilizer after being treated, and a large amount of clear liquid can be harmless and resourced by cultivating microalgae in it.

As a photoautotrophic organism, microalgae have been widely concerned for their high photosynthetic efficiency and fast reproduction rate. During the growth process of microalgae, relying on its high photosynthetic efficiency, it absorbs CO ₂ in the air and uses it as a carbon source for the synthesis of its own cell matter to achieve the purpose of fixing CO ₂ in the air. Some microalgae can also use the organic carbon source in the water for facultative growth, and at the same time absorb some N and P compounds in the water body, thereby realizing the degradation of organic matter in the water body.

As a photosynthetic plant, microalgae will produce many metabolites with high added value in the process of photosynthesis, such as pigments, unsaturated fatty acids, proteins, vitamins, polysaccharides, growth factors, etc. These products make microalgae have high utilization value in many aspects. β-carotene (C ₄₀ H ₅₆ ), one of the carotenoids, is an orange-yellow fat-soluble compound, and is the most ubiquitous and stable natural pigment in nature. β-carotene exists in many natural foods, such as papaya, carrots, etc., and some species of Dunaliella can accumulate high β-carotene content in themselves, and some can even reach 14% of their own cell dry weight.

Contents of the invention

Aiming at the deficiencies in the art, the purpose of the present invention is to propose a method for resource utilization of livestock and poultry manure water-soluble fertilizer production wastewater for cultivating Dunaliella.

The process is divided into three parts. The first part is to dilute the production wastewater of livestock and poultry manure water-soluble fertilizer to the suitable range for the growth of Dunaliella; the second part is to adjust the concentration and ratio of nutrient elements in the production wastewater of livestock and poultry manure water-soluble fertilizer. And adjust the salinity value and pH value to achieve the environmental conditions suitable for the growth of Dunaliella; the third part is to insert Dunaliella into the pretreated livestock and poultry manure water-soluble fertilizer production wastewater and pass CO ₂ gas to cultivate and harvest Dunaliella. Through the operation of the above three parts, the recovery of ammonia nitrogen in the wastewater is realized, and high-value Dunaliella is obtained, which is used to produce carotene, effectively realizing the recycling of wastewater and reducing greenhouse gas emissions.

Realize the technical scheme of the object of the present invention to be specifically:

A resource utilization method for cultivating Dunaliella in livestock and poultry manure water-soluble fertilizer production wastewater, comprising the steps of:

1) Dilute the waste water from the production of livestock and poultry manure water-soluble fertilizer with water, and the dilution factor is 20 to 35 times;

₂ ) Add nutrient elements P, _Ca , Fe, Mg to the diluted livestock and poultry _manure water _- soluble fertilizer production wastewater. 2H ₂ O40～50mg/L, MgSO ₄ 7H ₂ O1000～1300mg/L, ferric citrate 4～6mg/L;

3) Use one or more of NaCl solution, seawater, and brine to adjust the salinity value of the wastewater to 150-200 (usually salinity has no unit, known as ‰), and control the pH value to 8.0-9.0;

4) inoculating Dunaliella sp. in the logarithmic growth phase into the wastewater diluted in step 1) for cultivation, the inoculum size is 0.2g dry weight/L to 0.3g dry weight/L;

5) Continuously culturing for 8-12 days, so that the growth of the microalgae reaches the plateau stage, and then the microalgae are harvested and used for the production of β-carotene.

The Dunaliella sp. used in the present invention belongs to the genus Dunaliella, strain number: FACHB-558, and was purchased from the Institute of Hydrobiology, Chinese Academy of Sciences (Address: Freshwater Algae Species Bank, Institute of Hydrobiology, Institute of Hydrobiology, Chinese Academy of Sciences, No. 7, East Hunan Road, Luojia, Wuhan).

Wherein, the livestock and poultry manure is chicken manure and/or pig manure, and in the livestock and poultry manure water-soluble fertilizer production wastewater, the COD concentration is 800-900 mg/L, the TN is 2800-3100 mg/L, and the NH ₃ -N concentration is 2000～2500mg/L, TP concentration 6.0～10.0mg/L.

After step 1) dilution, the NH ₃ -N concentration of the wastewater can reach 70-120 mg/L, which is the suitable range for the growth of Dunaliella.

In step 2), the nutrient salts NaH ₂ PO ₄ ·2H ₂ O, CaCl ₂ ·2H ₂ O, MgSO ₄ ·7H ₂ O, and ferric citrate should be added in order, and the next drug should be added in sequence after the previous drug is completely dissolved. Or formulated as a mother liquor for addition.

Preferably, in the step 4), the culture illumination is 1800-2500 lux, and the light-dark cycle ratio is 12:10-14.

Wherein, in the step 4), a mixed gas of CO ₂ and air with a CO ₂ volume ratio of 4-10% is introduced during the photoperiod of microalgae cultivation.

Wherein, in the step 3), the seawater and brine are sterilized, and the disinfection is to sterilize the liquid at 120-130° C. for 15-30 minutes.

Wherein, in the step 3), 0.2-2 mol/L hydrochloric acid and/or 0.2-2 mol/L NaOH solution is used to adjust the pH value.

More preferably, in the step 3), the salinity value of the wastewater is adjusted to 165-175 with NaCl solution or one of the sterilized seawater and brine, and then the pH value is adjusted to 8.5 with hydrochloric acid and/or NaO solution.

Wherein, in the step 5), after the growth of the microalgae reaches the plateau stage, the microalgae is harvested with an internal pressure vacuum fiber membrane, and the pore size of the hollow fiber membrane is 0.22 μm.

Further, the present invention also proposes the equipment used in the resource utilization method.

The equipment used for the method includes a photobioreactor, an ultrafiltration unit, a microalgae seed culture device, and an air intake unit;

The photobioreactor is provided with a waste water inlet for the production of livestock and poultry manure water-soluble fertilizer, and the microalgae seed culture device is connected to the photobioreactor through a pipeline.

The air intake unit includes a _CO2 intake pipeline and an air compressor, the _CO2 intake pipeline and the air compressor are connected to a mixed gas chamber, and the mixed gas chamber is connected to an aeration head through a pipeline, and the aerator The gas head is set at the bottom of the photobioreactor;

The outlet of the mixed solution of algae and waste water in the photobioreactor is connected to the ultrafiltration unit.

Wherein, the ultrafiltration unit includes an internal pressure hollow fiber membrane module, the photobioreactor algae liquid outlet is connected to the water inlet of the internal pressure hollow fiber membrane module, and the connecting pipeline is provided with a pressure gauge, a diaphragm pump, a valve, A rotameter; the concentrate outlet of the internal pressure hollow fiber membrane module is connected to a microalgae concentrate storage tank.

Specifically, the described method can be accomplished through the following steps:

1. Through the water pump, pump the livestock and poultry manure water-soluble fertilizer production wastewater from the wastewater inlet to the main body of the reactor, and add distilled water;

2. Add nutrient salts NaH ₂ PO ₄ ·2H ₂ O, CaCl ₂ ·2H ₂ O, MgSO ₄ ·7H ₂ O and ferric citrate to the wastewater in the reactor in sequence. Pay attention to adding in order, and add the next medicine in turn after the previous medicine is completely dissolved. Or formulated as a mother liquor for addition. Set the culture light intensity and light-dark cycle ratio;

3. Add microalgae seed solution to the treated wastewater until the dry weight of microalgae is 0.2-0.3g/L, and the total liquid volume is two-thirds of the reactor volume;

4. Adjust the pH value of the wastewater to 8.5, and open the mixed gas system. Open the CO ₂ pressure control valve and air compressor, adjust the CO ₂ flow meter and the air inlet flow meter, feed the mixed gas of CO ₂ and air into the reactor, and cultivate for 8 to 12 days;

5. Turn on the ultrafiltration system. Open the water inlet valve of the microalgae incubator, turn on the diaphragm pump, adjust the liquid flow meter, and control the water inlet flow and pressure of the ultrafiltration membrane; The algae concentrate flows out from the outlet of the membrane module concentrate, and the microalgae concentrate is collected in a storage tank.

The beneficial effects of the present invention are:

The method proposed by the present invention to recycle the nutrient elements in the production wastewater of livestock and poultry manure water-soluble fertilizer and produce high value-added Dunaliella is a waste water treatment that combines the treatment of livestock and poultry manure water-soluble fertilizer production wastewater, the recycling of nutrient elements and the production of biomass The method of resource utilization can not only remove pollutants in wastewater, but also produce biomass raw materials, which has multiple functions of environmental protection, cost saving, resource recovery, and nutrient element recycling.

The invention combines the output of high-value biomass with sewage treatment to create additional value to a certain extent, thereby further saving the economic cost of waste water treatment. After being treated by this process, the pollutant concentration of the livestock and poultry manure water-soluble fertilizer production wastewater is reduced by more than 90%, which greatly reduces the subsequent treatment burden of the wastewater.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the equipment for recovering and treating nutrients in the production wastewater of livestock and poultry manure water-soluble fertilizer according to the present invention.

In the figure, the corresponding relationship between numbers and component names is as follows:

Fig. 2 is the graph of the variation of biomass with time in Example 1 and the comparative example.

Fig. 3 is a time-varying diagram of β-carotene in Example 1 and a comparative example.

detailed description

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

Unless otherwise specified, the means adopted in the specific embodiment are conventional technical means in the field.

Example 1

In this example, the treated chicken manure water-soluble fertilizer production wastewater has a COD of 823.6 mg/L, a TN of 2979.3 mg/L, an NH ₃ -N concentration of 2166.3 mg/L, and a TP concentration of 9.6 mg/L.

As shown in Figure 1, the equipment used for the resource utilization of chicken manure water-soluble fertilizer production wastewater includes a photobioreactor 6, an ultrafiltration unit, a microalgae seed liquid culture device 4, and an air intake unit;

The treated chicken manure water-soluble fertilizer production wastewater is stored in the livestock and poultry manure water-soluble fertilizer production wastewater storage tank 1, and is connected to the bottom of the photobioreactor 6 through the first diaphragm pump 3, the livestock and poultry manure water-soluble fertilizer production wastewater inlet 2 and pipelines , the wastewater inlet is about 10 cm away from the bottom of the reactor, and the microalgae seed culture device 4 is a triangular flask, which is connected to the photobioreactor 6 through pipelines.

Described air intake unit comprises _CO2 intake line and air compressor 11, _CO2 intake line is connected with _CO2 high-pressure cylinder 12, and the other end of _CO2 intake line is connected with gas mixture chamber 8, and air compressor is also connected The mixed gas chamber 8 is connected to the aeration head 7 through a pipeline, and the aeration head 7 is arranged at the bottom of the photobioreactor 6 . An air outlet pipe 5 is arranged on the top of the photobioreactor 6 . The outlet of the mixed solution of algae and waste water in the photobioreactor 6 is connected to the ultrafiltration unit through a valve 13 .

The ultrafiltration unit includes an internal pressure type hollow fiber membrane module 17, and the pore size of the hollow fiber membrane is 0.22 μm; the outlet of the photobioreactor algae liquid is connected to the water inlet of the internal pressure type hollow fiber membrane module 17, and the connecting pipeline is provided with algae and Wastewater mixed liquid outlet valve 13, second diaphragm pump 14, rotameter 15 and pressure gauge 16; microalgae concentrated liquid storage tank 19 is connected to the concentrated liquid outlet of internal pressure hollow fiber membrane module 17. A filtrate outlet valve 18 is provided on the filtrate outlet 20 of the internal pressure type hollow fiber membrane module 17 .

Processing steps:

1. Through the water pump, pump 5L of livestock and poultry manure water-soluble fertilizer production wastewater from the wastewater inlet to the main body of the reactor, add 145L of distilled water, and the final NH ₃ -N content is 72.21mg/L.

2. Add nutrient salts NaH ₂ PO ₄ 2H ₂ O2.34g (15.6mg/L), CaCl ₂ 2H ₂ O6.6g (44mg/L), MgSO ₄ 7H ₂ O184 to the wastewater in the reactor in order .5g (1230mg/L), ferric citrate 0.75g (5mg/L). Set the culture light intensity to 2000 lux, the ratio of light to dark cycle L:D=12:12, each cycle is 12 hours respectively.

3. Sterilize the brine at 120-130°C for 15-30 minutes, adjust the salinity value of the wastewater to 170 with the sterilized brine, and then adjust the pH value to 8.5 with 1mol/L hydrochloric acid. Add microalgae seed solution to the treated wastewater until the dry weight of microalgae is 0.25g/L, and the total liquid volume is two-thirds of the volume of the main body of the reactor.

4. Adjust the pH value of the wastewater to 8.5, and open the mixed gas system. Open the _CO2 pressure control valve and the air compressor, adjust the _CO2 flowmeter and the air inlet flowmeter, feed a _CO2 mixed gas with a volume ratio of 10% into the reactor during the photoperiod, and cultivate for 12 days;

5. Turn on the ultrafiltration system. Open the water inlet valve of the microalgae incubator, turn on the diaphragm pump, adjust the liquid flow meter, and control the water inlet flow and pressure of the ultrafiltration membrane; The algae concentrate flows out from the outlet of the membrane module concentrate, and other containers are used to collect the microalgae concentrate.

comparative example

As contrast (CK), adopt the equipment of embodiment 1, wherein place the D.M. standard culture medium (D.mmedium) that distilled water prepares in the optical material reactor, other operating conditions are the same as embodiment 1.

After 12 days of growth, filter with a hollow fiber membrane module, and take the microalgae concentrate in the storage tank for testing. The biomass and ammonia nitrogen removal rate results of Example 1 and Comparative Example are shown in Table 1. The comparison of biomass over time is shown in Figure 2. Fig. 3 is a time-varying diagram of β-carotene in Example 1 and a comparative example.

Table 1 Biomass and ammonia nitrogen removal rate

Example 2

In this example, the treated chicken manure water-soluble fertilizer production wastewater has a COD of 869.4 mg/L, a TN of 2892.3 mg/L, an NH ₃ -N concentration of 2151.2 mg/L, and a TP concentration of 9.5 mg/L.

Processing steps:

1. Through the water pump, pump 5L of livestock and poultry manure water-soluble fertilizer production wastewater from the wastewater inlet to the main body of the reactor, add 135L of distilled water, and finally the NH ₃ -N content is 100.6mg/L. ;

2. Add nutrient salts to the wastewater in the reactor to NaH ₂ PO ₄ 2H ₂ O 15mg/L, CaCl ₂ 2H ₂ O 40mg/L, MgSO ₄ 7H ₂ O 1250mg/L, and ferric citrate 4mg/L. Set the culture light intensity to 2000 lux, the ratio of light to dark cycle L:D=12:12, each cycle is 12 hours respectively.

3. Use NaCl solution to adjust the salinity value of the wastewater to 170, and then use 1mol/L sodium hydroxide solution to adjust the pH value to 8.5. Add microalgae seed solution to the treated wastewater until the dry weight of microalgae is 0.28g/L, and the total liquid volume is two-thirds of the volume of the reactor main body.

4. Adjust the pH value of the wastewater to 8.5, and open the mixed gas system. Open the _CO2 pressure control valve and the air compressor, adjust the _CO2 flowmeter and the air inlet flowmeter, feed a _CO2 mixed gas with a volume ratio of 5% into the reactor within the photoperiod, and cultivate for 11 days;

5. Turn on the ultrafiltration system. Open the water inlet valve of the microalgae incubator, turn on the diaphragm pump, adjust the liquid flow meter, and control the water inlet flow and pressure of the ultrafiltration membrane; The algae concentrate flows out from the outlet of the membrane module concentrate, and other containers are used to collect the microalgae concentrate. The biomass in the collected microalgae concentrate was 960 mg/L, and the beta-carotene was 13 mg/L.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the present invention, some improvements and replacements can also be made, these improvements and replacements It should also be regarded as the protection scope of the present invention.

Claims (10)

1. feces of livestock and poultry Water soluble fertilizer factory effluent cultivates a resource utilization method for Dunaliella salina, it is characterized in that, comprises step:

1) by feces of livestock and poultry Water soluble fertilizer factory effluent dilute with water, extension rate is 20 ~ 35 times;

2) in the feces of livestock and poultry Water soluble fertilizer factory effluent after dilution, add nutritive element P, Ca, Fe, Mg, corresponding nutritive salt addition is NaH ₂pO ₄2H ₂o15.0 ~ 18.0mg/L, CaCl ₂2H ₂o40 ~ 50mg/L, MgSO ₄7H ₂o1000 ~ 1300mg/L, ironic citrate 4 ~ 6mg/L;

3) use salt angle value to 150 ~ 200 of one or more adjustment waste water in NaCl solution, seawater, bittern, and control ph is 8.0 ~ 9.0;

4) to step 1) inoculation is in logarithmic phase in waste water after dilution Dunaliella salina cultivates, and inoculum size is 0.2g dry weight/L to 0.3g dry weight/L;

5) cultured continuously 8 ~ 12 days, after making the growth of Dunaliella salina arrive plateau, gathers in the crops Dunaliella salina, and producing for β-carotene.

2. resource utilization method according to claim 1, is characterized in that, described feces of livestock and poultry is chicken manure and/or pig manure, and in described feces of livestock and poultry Water soluble fertilizer factory effluent, COD concentration is 800 ~ 900mg/L, TN is 2800 ~ 3100mg/L, NH ₃-N concentration is 2000 ~ 2500mg/L, TP concentration, 6.0 ~ 10.0mg/L.

3. resource utilization method according to claim 1, is characterized in that, described step 4) in, cultivation illuminance is 1800 ~ 2500lux, and light dark period is than being 12:10 ~ 14.

4. resource utilization method according to claim 3, is characterized in that, described step 4) in, pass into CO in the photoperiod that Dunaliella salina is cultivated ₂volume ratio is the CO of 4 ~ 10% ₂with air gas mixture.

5. recycling of water resource Application way according to claim 1, is characterized in that, described step 3) in, described seawater and bittern are through sterilization, and described sterilization is by liquid sterilizing 15 ~ 30min at 120 ~ 130 DEG C.

6. recycling of water resource Application way according to claim 1, is characterized in that, described step 3) middle by 0.2 ~ 2mol/L hydrochloric acid and/or 0.2 ~ 2mol/LNaOH solution adjust ph.

7. according to the arbitrary described resource utilization method of claim 1 ~ 6, it is characterized in that, described step 3) in, with the seawater after NaCl solution or sterilization, a kind of salt angle value to 165 ~ 175 regulating waste water in bittern, use hydrochloric acid and/or NaOH solution adjust ph to 8.5 afterwards.

8. according to the arbitrary described sewage recycling Application way of claim 1 ~ 6, it is characterized in that, described step 5) in, after making the growth of Dunaliella salina arrive plateau, gathered in the crops by Dunaliella salina with inner pressed vacuum tunica fibrosa, the pore size filter of tunica fibrosa is 0.22 μm.

9., according to the arbitrary described resource utilization method of claim 1 ~ 6, it is characterized in that, the equipment for described method comprises bioreactor, ultra filtration unit, micro-algae seed culture device, air admission unit;

Described bioreactor is provided with feces of livestock and poultry Water soluble fertilizer factory effluent water-in, and micro-algae seed culture device connects described bioreactor by pipeline

Described air admission unit comprises CO ₂admission passage and air compressor, described CO ₂admission passage and air compressor are connected with mixed air vessel, and described mixed air vessel is connected with aeration head by pipeline, and described aeration head is arranged on bottom bioreactor;

The algae of described bioreactor is connected described ultra filtration unit with waste water mixture export.

10. according to the arbitrary described resource utilization method of Claims 1 to 4, it is characterized in that, described ultra filtration unit comprises inner pressed hollow fiber film assembly, the outlet of bioreactor algae liquid connects the water-in of described inner pressed hollow fiber film assembly, connecting pipeline is provided with tensimeter, surge pump, valve, spinner-type flowmeter; The concentrated solution outlet of described inner pressed hollow fiber film assembly is connected with micro-algae concentrated solution hold-up vessel.