CN108249574A - It is a kind of to handle pig farm breeding wastewater using microalgae and produce the device and its technique of algae powder - Google Patents

Abstract

A kind of to handle pig farm breeding wastewater using microalgae and produce the device and its technique of algae powder, which includes wastewater disposal basin, filter device, duct type bioreactor, spray equipment, feeder, ultrafiltration apparatus, centrifuge, clear water reserviors；The technique includes the following steps：(1) by pig farm breeding wastewater carry out two level pretreatment, be placed in bioreactor, handled by sterilizing and bacterial system；(2) microalgae is inoculated in the bioreactor equipped with piggery wastewater, is harvested after being cultivated；On-line checking water body data system is included in bioreactor：It is in situ to mend carbon pH feed back control systems and spray automatic cooling system, dissolved oxygen detecting system；(3) harvesting obtains algae solution, obtains algal gel by centrifugation, and be dried to obtain algae powder.The present invention eliminates or reduces to greatest extent the discharge of waste, achievees the purpose that energy saving, emission reduction, synergy, Resource recovery, is applicable in piggery wastewater large-scale purification and handles and produce algae powder, realizes resource Sustainable Development and Utilization.

Description

A device and process for using microalgae to treat pig farm wastewater and produce algae powder

technical field

The invention relates to a pig farm wastewater treatment device and a process method thereof, belonging to the technical field of sewage treatment, and in particular to an integrated technical system for treating and purifying pig farm wastewater and producing algae powder using microalgae.

Background technique

In recent years, my country's livestock and poultry breeding industry has continued to develop, the discharge of breeding wastewater has also increased year by year, and the pressure on environmental pollution prevention and control has continued to increase. In 2015, the number of pigs slaughtered in my country reached 708 million, and the discharge of pig raising wastewater was as high as 1 million to 1.5 million tons per day. Aquaculture pollution has become the largest source of pollution after industrial pollution and domestic pollution.

At present, domestic large-scale pig farms are equipped with anaerobic fermentation treatment systems. After anaerobic fermentation, most of the organic matter in the wastewater is removed, and the chemical oxygen demand (COD) and biochemical oxygen demand (BOD) are greatly reduced. Kill some pathogenic microorganisms, and the generated biogas can be used as clean energy. However, the fermentation period is too long, the floor area is large, the biogas generated is unstable, the sludge at the bottom of the fermentation tank cannot be recovered, and the nitrogen and phosphorus content in the biogas slurry after fermentation is high, which is difficult to meet the national emission standards. of sewage. Pig farming wastewater contains N, P, Mg, Zn, Ca and other elements. Direct discharge without utilization not only wastes resources, but also increases environmental pressure.

Chlorella pyrenoidosa has high nutritional value, and its cells are rich in protein, pigments (chlorophyll and carotenoids, etc.), fatty acids, carbohydrates, minerals and multivitamins. In 2012, the provisions of the "New Resource Food Management Measures" approved Chlorella pyrenoidosa as a new resource food. Chlorella pyrenoidosa has various nutritional methods, simple growth requirements, and strong tolerance. It can use carbon, nitrogen, and phosphorus in wastewater to synthesize its own complex cell components, thereby effectively removing nutrients in wastewater. Wide range of algae species. Chlorella treatment of wastewater is an effective way of recycling wastewater, and its application in municipal wastewater, agricultural wastewater, and aquaculture wastewater has attracted widespread attention.

Therefore, it is very necessary to design a new and complete microalgae treatment process for pig farm wastewater to solve the current environmental pollution of pig farm wastewater and to achieve repeated and sustainable resource utilization and environmentally friendly green production.

Contents of the invention

In order to overcome the deficiencies of the prior art, the present invention provides a process for using microalgae to treat pig farm breeding wastewater and produce algae powder.

In order to achieve the above object, the present invention adopts the following technical solutions:

The invention provides a device for using microalgae to treat pig farm breeding wastewater and produce algae powder, including a waste water tank, a filter device, a pipeline photobioreactor, a spray device, an air supply device, an ultrafiltration device, a centrifuge, and clean water pool;

The wastewater pool is connected to the pipeline photobioreactor after passing through the filter device; the pipeline photobioreactor is respectively connected to the circulation bucket and the water pump through a plurality of curved pipelines; the circulation bucket has an opening on one side and a bottom opening; one end of the pipe-type photobioreactor is connected to the bottom opening of the circulation barrel, and a first butterfly valve is arranged on the pipeline; the other end of the pipe-type photobioreactor is connected to the pipeline A water pump, and a second butterfly valve and a drain port are arranged on the pipeline; the water pump is connected to the side opening of the circulating barrel through a pipeline, and the pipeline is provided with a ventilation interface, and the air supply device is connected to the photobioreactor through the ventilation interface. The pipelines are connected; the ultrafiltration device is connected to the drain port through the pipeline; the centrifuge and the clear water pool are respectively connected to the ultrafiltration device through the pipelines.

Further, the photobioreactor pipe is preferably a transparent hard plastic pipe or a film pipe whose pipe wall is made of PVC.

Further, the circulation barrel is provided with a temperature detection and control system, a pH detection and control system, and a vent.

Further, the water pump is connected to the side opening of the circulation barrel through a pipeline, and a filter screen and a dissolved oxygen meter are respectively arranged on the pipeline.

Further, the gas supply device is an ozone generator or a carbon dioxide cylinder; the carbon dioxide cylinder is provided with a pressure reducing valve.

The present invention also provides a process for using microalgae to treat pig farm wastewater and produce algae powder, comprising the steps of:

(1) Carry out secondary pretreatment of pig farm breeding wastewater, place it in a photobioreactor, and process it through a disinfection and sterilization system;

(2) Inoculate the activated microalgae in the photobioreactor equipped with pig farm wastewater, harvest after cultivation; the photobioreactor includes an online detection water body data system: in-situ carbon supplementation-pH feedback control device And spray automatic cooling system, dissolved oxygen detection system;

(3) Harvesting the obtained algae liquid, centrifuging to obtain algae mud, and drying to obtain algae powder.

Further, in step (1), the waste water used is pig farming-related waste water, the total nitrogen content is above 303 mg/L, the ammonia nitrogen content is above 342 mg/L, the total phosphorus content is above 91 mg/L, and the COD content is 327 mg/L Above, pH 6.0-8.0 or so.

Further, in step (1), the secondary pretreatment is to use activated carbon filter and sand filter device to pretreat the aquaculture wastewater; the photobioreactor is preferably a pipeline-type photobioreactor for cultivation , the pipe wall is a transparent hard plastic pipe or a film pipe made of PVC; the disinfection and sterilization system adopts the ozone disinfection method.

Further, in step (2), the microalgae used are selected from the microalgae of the genus Chlorella; the inoculated microalgae are in the logarithmic growth phase; the in-situ carbon replenishment-pH feedback control device includes a carbon dioxide supply device, a neutralization control System device; the pH value of the water body is controlled between 7.0-7.5; the spray automatic cooling system automatically turns on the spray device when the water temperature is 40°C higher than the set value;

Further, in step (2), when the OD value of Chlorella pyrenoidosa reaches 2.2±0.2 or the content of NH ₄ ⁺ -N (mg/L) and PO ₄ ^3- (mg/L) is lower than 5 mg/L when harvesting.

Further, in step (3), the algae mud is collected by an ultrafiltration device and a centrifuge, and the algae mud is freeze-dried by an ultra-low temperature freeze dryer to recover the biomass of Chlorella pyrenoidosa.

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

(1) The process cycle is short and there is no secondary waste generation;

(2) At the same time of treating pig farm wastewater, _CO2 emission reduction and algae biomass recovery can be achieved, reducing the production cost of Chlorella pyrenoidosa; maximally eliminating or reducing waste discharge, achieving energy saving, emission reduction, and increase The purpose of improving efficiency and recycling resources is to realize green production of energy saving and emission reduction; to improve the utilization efficiency of biomass energy, to apply to the large-scale purification treatment of pig farm wastewater and to produce algae powder, and to realize sustainable development and utilization of resources.

(3) For the first time, a thin film pipe reactor was used, which greatly reduced the production cost of large-scale cultivation; for the first time, a flat film pipe reactor was used to cultivate Chlorella pyrenoidosa under outdoor conditions. It grows well in tube reactors and can tolerate high outdoor temperatures in summer.

Description of drawings

Fig. 1 is a composition diagram of a device for treating pig farm wastewater and producing algae powder using microalgae according to the present invention.

In the figure: 10-Wastewater pool, 20-Filtration device, 30-Photobioreactor, 31-Circulation barrel, 311-Air vent, 32-Pipeline, 33-First butterfly valve, 34-Second butterfly valve, 35-Water outlet , 36-water pump, 37-filter, 38-ventilation interface, 39-dissolved oxygen interface, 40-spray device, 50-air supply device, 51-pressure reducing valve, 60-ultrafiltration device, 70-centrifuge, 80-clear water pool

Fig. 2 is a process flow chart of the present invention using microalgae to treat pig farm wastewater and produce algae powder.

Figure 3 shows the change of dry weight of Chlorella pyrenoidosa in a 600L vertical pipe reactor; the culture conditions are: pig farm wastewater fermentation biogas slurry, pH 7.0-7.5, natural light.

Fig. 4 is the variation of the dry weight of Chlorella pyrenoidosa in a vertical 1500L vertical pipeline reactor; the culture conditions are: the original breeding wastewater of pig farms, pH 7.0-7.5, and natural light.

Figure 5 shows the change of the dry weight of Chlorella pyrenoidosa in a 1000L flat-walled pipe reactor; the culture conditions are: fermented biogas slurry from pig farm raw wastewater, pH 7.0-7.5, and natural light.

In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described in conjunction with the accompanying drawings and specific embodiments.

Detailed ways

As shown in Figure 1, a kind of device that utilizes microalgae to process pig farm breeding waste water and the technology that produces algae flour is required, comprises waste water pool 10, filtering device 20, pipeline type photobioreactor 30, spraying device 40, supply Gas device 50, ultrafiltration device 60, centrifuge 70, clear water tank 80.

The wastewater pool 10 is connected to the pipeline photobioreactor 30 after passing through the filtering device 20 .

The photobioreactor 30 can realize online detection of water body data and automatic control of water body temperature and pH value.

The preferred pipe-type photobioreactor of the present invention is respectively connected to a circulation barrel 31 and a water pump 36 through a plurality of curved pipes 32 .

The circulation barrel 31 has a side opening and a bottom opening: one end of the pipeline 32 of the pipeline photobioreactor is connected to the bottom opening of the circulation barrel 31, and a first butterfly valve 33 is arranged on the pipeline; The other end of the pipeline 32 of the pipeline photobioreactor is connected to a water pump 36, and a second butterfly valve 34 and a water outlet 35 are arranged on the pipeline.

The water pump 36 is connected to the side opening of the circulation barrel 31 through a pipeline, and a ventilation interface 38 is arranged on the pipeline, and the air supply device 50 is connected to the pipeline of the photobioreactor through the ventilation interface 38 .

The circulation barrel 31 is provided with a vent 311, which functions to allow the required carbon dioxide to enter the system and discharge the generated oxygen during the process of cultivating microalgae.

The circulating barrel 31 is provided with a temperature detection and control system and a pH detection and control system.

The photobioreactor pipe 32 is preferably a transparent hard plastic pipe or a film pipe whose pipe wall is made of PVC.

The device controls the flow direction of the culture system through butterfly valves 33 and 34 .

The water pump 36 is connected to the side opening of the circulation barrel 31 through a pipeline, and a filter screen 37 and a dissolved oxygen meter 39 are respectively arranged on the pipeline.

The function of the water pump 36 is to circulate the cultivation system in the pipeline photobioreactor to fully exchange the gas and nutrients in the system, which is more conducive to the cultivation of microalgae.

The function of the filter screen 37 is to remove impurities in the system to ensure that the water pump is not blocked.

The function of the dissolved oxygen meter 39 is to detect the photosynthesis efficiency of the algae by the dissolved oxygen percentage, that is, the more dissolved oxygen, the more oxygen the algae emits, and when the dissolved oxygen value exceeds 150%, the system automatically adjusts the water pump to speed up the circulation of the culture system The flow rate is to discharge excess oxygen from the vent 311 to prevent oxygen inhibition, and it is a dissolved oxygen feedback control system.

In-situ carbon replenishment-pH feedback system, including carbon dioxide supply device, neutralization control system device, can realize the control of pH value of water between 7.0-7.5.

The gas supply device 50 is an ozone generator or a carbon dioxide steel cylinder: when an ozone generator is used, the wastewater in the device can be subjected to ozone sterilization treatment; when a carbon dioxide steel cylinder is used, it is a carbon dioxide supply device of the device.

The carbon dioxide steel cylinder is provided with a pressure reducing valve 51, and its function is that when the pH value detected by the pH detection and control system in the circulation barrel 31 is higher than the set value of 7.5, the pressure reducing valve is opened to adjust the pH of the cultivation environment, which is Neutralize control system devices.

The spray automatic cooling system can detect the water temperature online through the temperature detection and control system set in the circulation barrel 31. The water temperature is higher than the set value of 40 ° C. The spray device 40 is automatically turned on. The spray device 40 is equipped with a refrigeration system, which can reduce the temperature of the cultivation the temperature of the system.

Harvest when the OD value of Chlorella pyrenoidosa reaches 2.2±0.2 or when the content of NH ₄ ⁺ -N (mg/L) and PO ₄ ^3- (mg/L) is lower than 5 mg/L, through the outlet 35 discharge.

The ultrafiltration device 60 is connected to the drain port 35 through a pipeline; the centrifuge 70 and the clean water pool 80 are respectively connected to the ultrafiltration device 60 through pipelines.

As shown in FIG. 2 , it is a process flow chart of the present invention for treating pig farm wastewater and producing algae powder using microalgae. In the photobiological pipeline reactor, chlorella is cultivated with aquaculture wastewater or its fermented biogas slurry as the medium, and various elements such as N, P, Mg, Zn, and Ca in the wastewater are reused and transformed into chlorella pyrenoidosa of biomass. Specific steps are as follows:

(1) Secondary pretreatment of pig farm wastewater, placed in a photobioreactor, and treated by a disinfection and sterilization system.

The wastewater is related to pig farming, with a total nitrogen content of more than 303mg/L, an ammonia nitrogen content of more than 342mg/L, a total phosphorus content of more than 91mg/L, a COD content of more than 327mg/L, and a pH of about 8.0.

The pretreatment process is to use activated carbon filter and sand filter device to pretreat the aquaculture wastewater, in order to remove the solids in the wastewater and reduce the chromaticity of the water quality, thereby reducing its blocking of light, which is beneficial to the cultivation of microalgae.

The disinfection and sterilization system uses the ozone disinfection method to remove harmful microorganisms in the culture system, thereby promoting the growth of microalgae.

(2) Inoculate logarithmic Chlorella in a photobioreactor equipped with pig farm wastewater for cultivation. During the cultivation period, an in-situ carbon replenishment-pH feedback control device is used to supplement CO2 to control the pH value of the cultivation system, a spray automatic cooling system is used to control the system temperature, and a water pump is used to circulate and exchange gas and nutrients to cultivate Chlorella. Harvest when the OD value of Chlorella pyrenoidosa reaches 2.2±0.2 or when the content of NH4+-N (mg/L), PO43- (mg/L) is lower than 5 mg/L.

The microalgae used can basically be any suitable microalgae. The general requirements are dominant algae species with high nitrogen and phosphorus removal rate, wider temperature tolerance range and fast growth. The preferred algae species is Chlorella microalgae.

The treatment of pig farm wastewater can basically be carried out in any device. It is preferred to use a pipeline-type photobioreactor for cultivation, and the pipe wall is a transparent hard plastic pipe or a soft film pipe made of PVC.

The microalgae cultivation and treatment process can effectively reduce the concentration of total nitrogen, ammonia nitrogen and total phosphorus in wastewater, and basically meet the national standard for the discharge of pollutants in the livestock and poultry industry: COD is less than 100mg/L, ammonia nitrogen is less than 25mg/L, and total phosphorus (calculated as P ) is less than 3.0mg/L.

In order to confirm that the microalgae is in the optimal growth condition, the microalgae cells can be harvested when the OD680 value of the microalgae cells reaches 2.2 and above.

(3) After the cultivation, the algae fluid is harvested by an ultrafiltration device, centrifuged to obtain algae mud, and dried to obtain algae powder. Thereby, nutrients such as nitrogen and phosphorus in the waste water are converted into the biomass of Chlorella pyrenoidosa, realizing the recycling of the biomass and purifying the water quality at the same time.

The algal mud is collected by an ultrafiltration device and a centrifuge, and the algal mud is freeze-dried by an ultra-low temperature freeze dryer to recover the chlorella biomass. After testing, it is determined that the protein content of the stem cells in the algae powder is higher than 50%, which meets the production standard of the algae powder raw material for feed, and can be used as a source of feed material for aquaculture.

The present invention will be described in further detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

Embodiment 1 Utilizes pig farm waste water to cultivate in the PVC pipeline reactor of 600L

1.1 Activation of algal species and preparation of seed solution

Pick a single algae colony from the activated Basal medium solid plate, and inoculate it into a 250mL Erlenmeyer flask filled with Basal medium (containing 10g/L glucose), and the filling volume is 100mL. Place them in a constant temperature shaker with a temperature of 28°C, 4000 lux, and 150 r/min and cultivate them for 6 days.

Using the improved Basal medium, in the ultra-clean workbench, the pre-cultivated first-grade Chlorella seed solution was inserted into a 2L large triangular flask according to the inoculum size 10% (v/v), and the liquid volume was 900mL. Cultivated under natural conditions in a large outdoor shaker.

1.2 Pretreatment and inoculation of wastewater

The fermented biogas slurry of pig farming wastewater is passed through sand filtration and activated carbon filtration for secondary treatment, and then passed into a 600L photobioreactor. After 30 minutes of ozone disinfection, the gas is diffused for 2 hours. The seed solution of Chlorella pyrenoidosa was inoculated into the photobioreactor.

1.3 Test method

1.3.1 Determination of COD, TN, TP content in wastewater

Using a special kit from HACH Company in the United States, the measurement ranges of COD, TN, and TP are 200-1500mg/L, 0-150mg/L, and 0-3.5mg/L, respectively. According to the standard operation procedure of the kit, the sample was diluted to the measurement range, and after adding the corresponding reagents, it was digested on the digester DRB200 (COD: 150°C for 2h; TN: 105°C for 30min; TP: 150°C for 30min). After the digestion is completed, take it out and cool it down, then add reagents according to the corresponding operation steps, and place it in the spectrophotometer DR2700 for measurement and reading. Take the average value after repeating the measurement of each sample three times, and multiply the measurement reading by the dilution factor of the sample, which is the content of COD, TN, and TP in the water sample to be tested.

1.3.2 Determination of NH ₃ -N, PO ₄ ^3- content in wastewater

Use Italy HANNA HI83200 multi-parameter water quality analyzer to measure. Select an appropriate range, dilute the sample to be tested to the measurement range, and add the corresponding reagents to the cuvette according to the instrument instructions for measurement and reading.

1.3.3 Biomass

The culture medium was centrifuged at high speed to remove the supernatant, and the obtained algae sludge was resuspended with deionized water, and then centrifuged at a low speed (3000r/min) for 5 minutes to remove the suspended supernatant with bacteria, and repeated centrifugation until the supernatant was colorless and transparent . Transfer the algae mud to a weighed 10mL centrifuge tube, centrifuge at a high speed (12000r/min for 5 minutes), remove the supernatant, dry it in a 60°C oven and weigh it.

1.3.4 Determination of OD value

The absorbance of the sample at 680 nm was measured using a UV-Vis spectrophotometer.

1.4 Result Analysis

In this example, the water quality parameters of the pig farm wastewater and pretreatment are shown in Table 1. The result analysis shows that the pretreatment process can reduce the COD and total nitrogen of the pig farm wastewater to a certain extent while reducing the solids and chroma in the water. , ammonia nitrogen and total phosphorus content.

Table 1 Pig farm wastewater and water quality parameters after pretreatment

The removal rate of COD, TN, TP, NH ₃ -N, PO ₄ ^3- , and chroma are used as indicators to reflect the purification of wastewater. As shown in Table 2, it can be seen from Table 2 that the removal rate of PO ₄ ^3- before and after cultivation can reach 100%. The removal rates of COD, TN, TP, NH ₃ -N, and chroma were 68.87%, 78.41%, 98.24%, 94.64%, and 80.11%, respectively.

Table 2 COD, TN, TP, NH ₃ -N, PO ₄ ³ -, chroma removal rate (%) statistics

parameter COD NH ₃ -N PO ₄ ³ - TN TP Chroma secondary filter 23.79±0.02 29.61±0.06 30.12±0.06 10.67±0.01 22.29±0.01 37.31±0.01 before and after training 68.87±0.04 94.64±0.02 100±0.01 78.41±0.07 98.24±0.02 80.11±0.03

From the analysis in Figure 3, it can be seen that under the condition of the initial inoculation density of 0.08g/L, after 204 hours of cultivation, the dry weight of Chlorella pyrenoidosa reached the maximum value of 0.52g/L. The algae powder is collected by the method of circular harvesting, and the yield can reach 0.93g/L after three accumulations.

Example 2 Utilize pig farm wastewater to cultivate Chlorella in a 1500L PVC pipe-type photobioreactor

2.1 Activation of algae species and preparation of seed solution: the method is the same as 1.1

2.2 Pretreatment and inoculation of wastewater

The fermented biogas slurry of pig farming wastewater is passed through sand filtration and activated carbon filtration for secondary treatment, and then passed into a 1500L photobioreactor. After 30 minutes of ozone disinfection, the gas is diffused for 2 hours. The seed solution of Chlorella pyrenoidosa was inoculated into the photobioreactor.

2.3 Test method: the method is the same as 1.3

2.4 Result Analysis

Table 3 Pig farm wastewater and water quality parameters after pretreatment

Table 4 COD, TN, TP, NH ₃ -N, PO ₄ ^3- , chroma removal rate (%) statistics

parameter COD NH ₃ -N PO ₄ ^3- TN TP Chroma secondary filter 23.79±0.02 29.62±0.06 30.01±0.06 10.67±0.01 22.29±0.01 37.31±0.01 before and after training 45.54±0.03 91.72±0.009 80.02±0.02 52.11±0.03 74.58±0.04 89.08±0.06

It can be seen from Tables 3 and 4 that COD, TN, TP, NH ₃ -N, PO ₄ ^3- , and chroma removal rate are used as indicators to reflect the purification of wastewater. The removal rates of NH ₃ -N before and after cultivation can reach 91.72%, and the removal rates of COD, TN, TP, PO ₄ ^3- , and chroma are 45.54%, 52.11%, 74.58%, 80.02%, and 89.08%, respectively.

From the analysis in Figure 4, it can be seen that under the condition of the initial inoculation density of 0.51g/L, after 144h of cultivation, the dry weight of Chlorella pyrenoidosa reached the maximum value of 0.48g/L. After three cycles of recovery, the yield can reach 0.82g/L.

In addition, compared with Example 1, it can be drawn that the output of Chlorella is related to the efficiency of photosynthesis, the smaller the light path, the higher the photosynthetic efficiency, 600L (light path is 4.5cm) than 1500L (light path is 10cm) ) of PVC plastic pipe with a high yield of 11.83%.

Example 3 Utilize pig factory wastewater to cultivate Chlorella in a 1000L tiled film pipeline reactor

3.1 Activation of algae species and preparation of seed solution: the method is the same as 1.1

3.2 Pretreatment and inoculation of wastewater

The fermented biogas slurry of pig farming wastewater is subjected to secondary treatment through sand filtration and activated carbon filtration respectively, and then passed into a 1000L flat film pipeline reactor. After 30 minutes of ozone disinfection, the gas is diffused for 2 hours. The seed solution of Chlorella pyrenoidosa was inoculated into the photobioreactor.

3.3 Test method: the method is the same as 1.3

3.4 Result Analysis

Table 5 Pig farm wastewater and water quality parameters after pretreatment

Table 6 COD, TN, TP, NH ₃ -N, PO ₄ ^3- , chroma removal rate (%) statistics

parameter COD NH ₃ -N PO ₄ ^3- TN TP Chroma secondary filter 5.61±0.032 5.82±0.075 7.63±0.06 19.83±0.053 2.71±0.012 7.25±0.67 before and after training 43.61±2.6 81.42±3.7 100±0.01 73.43±0.67 71.91±0.36 14.1±0.69

As shown in Tables 5 and 6, COD, TN, TP, NH ₃ -N, PO ₄ ^3- , and chroma removal rate are used as indicators to reflect the purification of wastewater. It can be seen from Table 6 that the removal rate of PO ₄ ^3- before and after cultivation can reach 100%, and the removal rates of COD, TN, TP, NH ₃ -N, and chroma are 43.61%, 73.43%, 71.91%, and 81.42% respectively , 14.1%.

From the analysis in Figure 5, it can be seen that under the condition of the initial inoculation density of 0.08g/L, after 84 hours of cultivation, the dry weight reached the maximum value of 0.13g/L.

In this experiment, Chlorella pyrenoidosa was cultivated in the flat-film pipe reactor under outdoor conditions for the first time, and the results showed that Chlorella pyrenoidosa grew well in the flat-film pipe reactor and could withstand the outdoor high temperature in summer.

In summary, the inventors of the present application compared the effects of photobioreactors with different materials and light paths on the output of Chlorella pyrenoidosa and the purification effect of waste water through Examples 1-3 in the process of developing the technical solution of this process. .

The results show that using a small-pipe photobioreactor with a light path of 4.5cm and a volume of 600L to cultivate Chlorella pyrenoidosa, the maximum dry weight is 0.51g/L, and the output can reach 0.93g/L, which is basically in line with the national standard for livestock and poultry breeding. Pollutant discharge standards (COD less than 100mg/L, ammonia nitrogen less than 25mg/L, total phosphorus (calculated as P) less than 3.0mg/L), and the purification effect on pig farm wastewater is also the best.

However, compared with flat film pipe reactors, the cost of PVC pipe reactors is relatively high. Chlorella pyrenoidosa grows well in the cheap flat-film pipe reactor, which can withstand the high temperature outdoors in summer. The removal rate of PO ₄ ^3- reaches 100%, and the removal rate of NH ₃ -N reaches 81.12%. Therefore, industrial production can be carried out by using flat film pipe reactors.

The present invention uses microalgae to treat pig farm wastewater and produce a complete set of technology for algae powder, which can realize the purification of wastewater water quality and at the same time realize the accumulation of microalgae biomass and carbon emission reduction, effectively reduce the treatment cost of wastewater, and realize the comprehensive development of resources Utilization, has the double value of economy and environmental protection, is suitable for the wastewater purification treatment of large, medium and small pig farms and other breeding industries, and is very suitable for large-scale promotion in livestock and poultry breeding enterprises.

The present invention is not limited to the above-mentioned embodiments, if the various changes or modifications of the present invention do not depart from the spirit and scope of the present invention, if these changes and modifications belong to the claims of the present invention and the equivalent technical scope, then the present invention is also These modifications and variations are intended to be included.

Claims (10)

1. a kind of handle pig farm breeding wastewater using microalgae and produce the device of algae powder, it is characterised in that：

Including wastewater disposal basin, filter device, duct type bioreactor, spray equipment, feeder, ultrafiltration apparatus, centrifuge, Clear water reserviors；

It is connected after the filtered device of wastewater disposal basin with the duct type bioreactor；

The duct type bioreactor connects circulation barrel and water pump respectively by the pipeline of multiple bendings；

The circulation barrel has a side opening and a bottom opening；

One end pipeline of the duct type bioreactor connects the bottom opening of the circulation barrel, and is provided on pipeline First butterfly valve；

The other end pipeline connection water pump of the duct type bioreactor, and second butterfly valve, draining are provided on pipeline Mouthful；

The water pump connects the side openings of the circulation barrel by pipeline, and ventilation interface, the feeder are provided on pipeline By ventilating, interface is connected with the pipeline of bioreactor；

The ultrafiltration apparatus is connected by pipeline with discharge outlet；The centrifuge, clear water reserviors are filled respectively by pipeline and ultrafiltration It puts and is connected.

2. the apparatus according to claim 1, it is characterised in that：The bioreactor pipeline preferably use tube wall for The clear hard plastic tube or film tube of PVC material.

3. the apparatus according to claim 1, it is characterised in that：The circulation barrel be provided with temperature detection and control system, PH inspection and control systems, blow vent.

4. the apparatus according to claim 1, it is characterised in that：It opens the side that the water pump connects the circulation barrel by pipeline Mouthful, it is respectively arranged with strainer, dissolved oxygen instrument on pipeline.

5. the apparatus according to claim 1, it is characterised in that：The feeder is ozone generator or titanium dioxide carbon steel Bottle；Pressure reducing valve is provided on the carbon dioxide steel cylinder.

6. a kind of technique for handling pig farm breeding wastewater using microalgae and producing algae powder, which is characterized in that include the following steps：

(1) pig farm breeding wastewater is subjected to two level pretreatment, is placed in bioreactor, is handled by sterilizing and bacterial system；

(2) microalgae of the inoculation Jing Guo activation process in the bioreactor equipped with piggery wastewater, harvests after being cultivated；Light Bioreactor includes on-line checking water body data system：It is in situ to mend carbon-pH feed back control systems and the automatic cooling system of spray System, dissolved oxygen detecting system；

(3) obtained algae solution is harvested, obtains algal gel by centrifugation, and be dried to obtain algae powder.

7. technique according to claim 6, it is characterised in that：

In step (1), waste water used cultivates related waste water for pig farm, and total nitrogen content is in more than 303mg/L, ammonia-nitrogen content More than 342mg/L, total phosphorus content are more than 91mg/L, and COD contents are more than 327mg/L, pH 6.0-8.0 or so.

8. technique according to claim 6, it is characterised in that：

In step (1), the two level pretreatment is that breeding wastewater is pre-processed using activated carbon filtering and sand filtering device；

The bioreactor that the bioreactor is preferably the duct type used is cultivated, and tube wall is PVC material Clear hard plastic tube or film tube；

The sterilizing and bacterial system processing is using ozone disinfection.

9. technique according to claim 6, it is characterised in that：

In step (2), microalgae used is selected from Chlorella microalgae；The microalgae of inoculation is in exponential phase；

Carbon-pH the feed back control systems in situ of mending include carbon dioxide feeding mechanism, neutralize control system device；

Water pH value is controlled between 7.0-7.5；

The spray automatic cooling system is higher than 40 DEG C of automatic opening spray equipments of setting value in water temperature；

In step (2), when the OD values of chlorella pyrenoidosa reach 2.2 ± 0.2 or NH₄ ⁺- N (mg/L) and PO₄ ^3-(mg/L) contain It is harvested when amount is less than 5mg/L.

10. technique according to claim 6, it is characterised in that：In step (3), using ultrafiltration apparatus and centrifugal collection Algal gel is lyophilized algal gel using cryogenic temperature freezing drying device, withdraws chlorella pyrenoidosa biomass.