CN107055946A - A kind of method that utilization chlorella purifies pig farm fermentation waste water - Google Patents

Abstract

The present invention proposes a kind of method that utilization chlorella purifies pig farm fermentation waste water, comprises the following steps：(1) enter regulating reservoir after the pretreatment of pig farm fermentation waste water and adjust pH=6.5 7.5 and waste strength；(2) chlorella carries out domestication culture in waste water, it is final obtain in volume fraction is 50% 70% waste water can fast-growth algae kind；(3) the algae kind seed liquor after domestication is inoculated into waste water, cultivated in closed photo bioreactor；(4) chlorella is harvested, wastewater treatment is completed.The method of the present invention is used purifies pig farm fermentation waste water in the stronger chlorella of adaptability, can preferably remove TN, TP and COD of waste water, solves current pig farm fermentation waste water using conventional method is not economical enough or the problem of direct exhaust emission environment；In addition, the chlorella of harvest can be used as other purposes, certain economic benefit is produced.

Description

A method of using chlorella to purify pig farm fermentation wastewater

technical field

The invention relates to a method for purifying pig farm fermentation waste water by using chlorella.

Background technique

With the development of the economy, the business model of the pig industry tends to be large-scale and develop rapidly. The amount of wastewater discharge is also increasing, and the ensuing environmental problems are becoming more and more serious. Fermentation of pig farm wastewater to produce biogas is a relatively common way to treat wastewater in intensive pig farms. However, the biogas slurry after fermentation is still high-concentration organic wastewater and cannot meet the discharge standards. Biogas slurry treatment methods after fermentation include artificial wetland method, biological pond method and MBR reactor treatment, etc., but these methods are difficult to be applied in practice due to problems such as high cost. Therefore, the main form of fermentation wastewater treatment in pig farms is simple Discharge directly after treatment.

Chlorella is a spherical single-celled freshwater algae. It is a highly efficient photosynthetic plant. It grows and reproduces by photoautotrophy. The protein, fat and carbohydrate content in the cells are very high, and there are many vitamins. It is edible and as bait.

Contents of the invention

The invention proposes a method for purifying pig farm fermentation waste water by using chlorella, which solves the problem that the current pig farm fermentation waste water is not economical or directly discharged to pollute the environment.

Technical scheme of the present invention is realized like this:

A method utilizing chlorella to purify fermented wastewater from pig farms, at least comprising the following steps:

(1) After the pig farm fermentation wastewater is pretreated, it enters the adjustment tank to adjust the pH=6.5-7.5 and the concentration of the wastewater;

(2) Chlorella is domesticated and cultivated in wastewater, and finally obtains algae species that can grow rapidly in wastewater with a volume fraction of 50%-70%;

(3) Inoculate the acclimated algae seed solution into the waste water and cultivate it in a closed photobioreactor;

(4) The chlorella is harvested, and the waste water treatment is completed.

Preferably, the pretreatment process in step (1) is as follows: after the pig farm fermented wastewater is separated from solid and liquid, the clear liquid enters the aeration tank for aeration, after 48 hours of aeration, enters the sedimentation tank for 2 hours, and the supernatant enters the disinfection tank, and uses strong Disinfect with chlorine essence, aerate for 30-60 minutes after 16-24 hours, and add sodium thiosulfate to neutralize.

Preferably, the added amount of the strong chloroquine is 6-30g/m3, and the added amount of sodium thiosulfate is 2-3 times of the quality of the strong chloroquine.

Preferably, in step (2), the chlorella is domesticated sequentially in waste water with a volume fraction of 20%-100%, and the chlorella is cultivated on a shaker in a constant temperature culture room, the culture temperature is 23-26°C, and the shaker speed is 180rmp/min, light 3000-4000lux, and finally screen out algae species that can grow rapidly in wastewater with a volume fraction of 50%-70%.

Preferably, step (3) specifically includes: inoculating the seed liquid that has been acclimatized and cultivated into the pretreated wastewater, and cultivating it in a closed photobioreactor with an inoculum volume fraction of 10%-20%, so that OD=0.2-0.3, the culture condition is pH=6.5-7.5, the light is 5000-6000 lux, the temperature is 23-26° C., and the culture is 9-12 days.

Preferably, the flocculant used for harvesting the chlorella in step (4) is ferric chloride, and the final concentration of ferric chloride in the algae liquid is 200-500mg/L, pH=6-7.

The beneficial effects produced by the present invention are as follows: the use of chlorella with strong adaptability to purify pig farm fermentation wastewater can better remove TN, TP and COD in wastewater, and solve the problem that traditional methods for pig farm fermentation wastewater are not economical or Directly discharge the problem of polluting the environment; in addition, the harvested chlorella can be used for other purposes and generate certain economic benefits.

detailed description

The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Apparently, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example

( ¹ ) After solid-liquid separation, the fermented wastewater from the pig farm enters the aeration tank for aeration. After aeration for 48 hours, it enters the sedimentation tank. The sedimentation time is 2 hours. After aeration for 30 minutes, add sodium thiosulfate 2.5 times the mass of strong chlorine to neutralize, then enter the adjustment tank to adjust the pH to 7 and adjust the concentration of wastewater with tap water.

(2) The fermented wastewater from pig farms after the above-mentioned treatment starts from a low concentration, and domesticates Chlorella in the wastewater with a volume fraction of 20-100% successively. The temperature is 23-26°C, the rotation speed of the shaker is 180rmp/min, and the light is 3000-4000lux. Finally, the algae species that can grow rapidly in the fermented wastewater of pig farms with a concentration of 50%-70% are screened out.

(3) Inoculate the algae seed solution that has been domesticated and expanded into the pretreated waste water, select three concentrations of 50%, 60%, and 70%, and cultivate them in a closed photobioreactor respectively. The fraction is 10%-20% of the waste water, so that OD=0.2-0.3, the culture conditions are PH=7, light of 5000-6000 lux, temperature 25°C, and culture for 12 days.

(4) After cultivating for one cycle, harvest Chlorella, the flocculant used is ferric chloride, and the final concentration of Ferric chloride in the algae liquid is 200-500mg/L, PH=6, after 2h, the chlorella The sedimentation rate can reach more than 95%, and the supernatant is discharged and collected to complete the wastewater treatment; after the chlorella is harvested, the supernatant after flocculation is taken to measure the COD, TN, TP and other index values.

After the pig farm fermentation wastewater was treated through the above steps, it was found that 60% of the wastewater could achieve the best purification effect, and the treatment results are shown in Table 1. After treatment, the final pollution indicators could meet the livestock and poultry breeding wastewater discharge standards.

Table 1: Pollution indicators before and after treatment of fermented wastewater from pig farms

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (6)

1. A method utilizing chlorella to purify pig farm fermented waste water, is characterized in that, comprises the following steps at least: (1) After the pig farm fermentation wastewater is pretreated, it enters the adjustment tank to adjust the pH=6.5-7.5 and the concentration of the wastewater; (2) Chlorella is domesticated and cultivated in wastewater, and finally obtains algae species that can grow rapidly in wastewater with a volume fraction of 50%-70%; (3) Inoculate the acclimated algae seed solution into the waste water and cultivate it in a closed photobioreactor; (4) The chlorella is harvested, and the waste water treatment is completed. 2. a kind of method utilizing chlorella to purify pig farm fermentation waste water as claimed in claim 1, it is characterized in that, in step (1), the pretreatment process is: after pig farm fermentation waste water is through solid-liquid separation, clear liquid enters The aeration tank is aerated, after 48 hours of aeration, it enters the sedimentation tank for 2 hours, and the supernatant enters the disinfection tank, and is disinfected with strong chlorine alcohol. After 16-24 hours, it is aerated for 30-60 minutes, and then neutralized by adding sodium thiosulfate. 3. a kind of method utilizing chlorella to purify pig farm fermented waste water as claimed in claim 2, is characterized in that, the addition of described strong chlorine essence is 6-30g/m , sodium thiosulfate addition is strong Chlorine quality 2-3 times. 4. a kind of method utilizing chlorella to purify pig farm fermented waste water as claimed in claim 1, is characterized in that, in step (2), successively domesticate chlorella in the waste water that volume fraction is 20%-100%, Chlorella is cultured on a shaker in a constant temperature culture room, the culture temperature is 23-26°C, the shaker speed is 180rmp/min, and the light is 3000-4000lux. Finally, the chlorella can be screened out in the waste water with a volume fraction of 50%-70%. Fast growing algal species. 5. A kind of method utilizing chlorella to purify pig farm fermentation waste water as claimed in claim 1, is characterized in that, step (3) is specifically: inoculate the seed liquid that acclimatizes and expand cultivation to the waste water after pretreatment , cultured in a closed photobioreactor, the inoculum volume fraction is 10%-20%, so that OD=0.2-0.3, the culture conditions are pH=6.5-7.5, light 5000-6000lux, temperature 23-26°C, Culture for 9-12 days. 6. a kind of method utilizing chlorella to purify pig farm fermented waste water as claimed in claim 1, is characterized in that, in the step (4), the flocculant used for collecting chlorella is ferric chloride, and three The final concentration of ferric chloride is 200-500mg/L, pH=6-7.