CN110776226A

CN110776226A - Method for treating excrement in pig farm

Info

Publication number: CN110776226A
Application number: CN201910904005.XA
Authority: CN
Inventors: 王文国; 蒋小妹; 张云红; 郑丹
Original assignee: Biogas Institute of Ministry of Agriculture
Current assignee: Biogas Institute of Ministry of Agriculture
Priority date: 2019-09-23
Filing date: 2019-09-23
Publication date: 2020-02-11

Abstract

The invention provides a method for treating excrement in a pig farm, which comprises the following steps: a. taking the pig farm excrement, inoculating activated sludge, carrying out anaerobic fermentation, simultaneously or respectively adding bitter soil and calcium hydrophosphate into a fermentation tank, and naturally precipitating after fermentation to obtain supernatant fluid 1; b. and c, adding magnesium chloride or dipotassium hydrogen phosphate into the supernatant 1 obtained in the step a, adjusting the pH to 9.0 by using plant ash, and naturally settling to obtain the plant ash.

Description

Method for treating excrement in pig farm

Technical Field

The invention belongs to the field of environmental protection and the field of renewable energy sources, and particularly relates to a novel method for treating feces in a pig farm.

Background

With the rapid development of livestock and poultry breeding industry, livestock and poultry manure is produced in large quantity, for example, 3000 piggeries in annual stockbreeding farms excrete manure about 2200t each year, urinate about 1000 tons each year, and discharge capacity is huge.

The piggery manure is used for biogas fermentation, so that the pressure of sewage discharge is relieved on one hand, and clean energy can be generated on the other hand. But the gas yield of directly carrying out biogas fermentation on the pig farm feces is low, and large-scale popularization is difficult; and the ammonia nitrogen in the methane-producing anaerobic fermentation is difficult to be effectively consumed, and the fermented wastewater still cannot meet the national strict ammonia nitrogen discharge standard.

The exploration of an economical and effective magnesium ammonium phosphate chemical precipitation process becomes a hotspot for treating the excrement in the high ammonia nitrogen pig farm at present. The chemical deposition process of magnesium ammonium phosphate is one technology capable of eliminating high concentration ammonia nitrogen and high concentration phosphate simultaneously and is based on NH in water system ₄ ⁺-N、PO ₄ ^3-And Mg ²⁺Magnesium ammonium phosphate precipitate can be generated, thereby achieving the effects of nitrogen and phosphorus removal; meanwhile, the solubility of magnesium ammonium phosphate is low, the effective separation of solid and liquid can be realized, compared with other ammonia nitrogen removal methods, the method is simple and convenient, and most importantly, the reaction product of the technology can be used as a slow release fertilizer, so that the ammonia nitrogen and phosphorus can be recycled.

At present, because the phosphate and magnesium content in the pig farm manure is low, the forming condition of magnesium ammonium phosphate is not satisfied; magnesium source and phosphorus source need to be added, and bitter earth (a mineral substance with the main component of magnesium oxide) and calcium hydrophosphate are chemical agents which are low in cost and easy to prepare, and can be directly added into the pig farm excrement to serve as the magnesium source and the phosphorus source with higher economic efficiency. But their use is limited because of their low solubility under alkaline conditions.

In addition, even if the traditional biogas fermentation process and the magnesium ammonium phosphate chemical precipitation process are combined, the problem of low methane production capability of the fermentation of the manure in the pig farm can not be solved theoretically.

Disclosure of Invention

The invention aims to provide a method for treating pig farm manure with methane production and deamination nitrogen production.

The technical scheme of the invention comprises the following steps:

a livestock and poultry manure treatment method comprises the following steps:

a. taking the pig farm excrement, inoculating activated sludge, carrying out anaerobic fermentation, simultaneously or respectively adding bitter soil and calcium hydrophosphate into a fermentation tank, fermenting for 20-30 days, and naturally precipitating to obtain a supernatant fluid 1;

b. adding bitter earth or dipotassium hydrogen phosphate into the supernatant fluid 1 to adjust the pH value to 8.5-9.5, and naturally settling to obtain a precipitate and a supernatant fluid 2.

Further, step b is adjusting the pH with plant ash.

Further, the livestock and poultry manure is pig farm manure.

Further, step b adjusted the pH to 9.0.

Further, in the step b, magnesium chloride or dipotassium hydrogen phosphate is added into the supernatant obtained in the step a, so that Mg is added ²⁺And PO ₄ ^3-The molar ratio of (a) to (b) is 1.

Further, adding bitter earth and calcium hydrogen phosphate in the step a to ensure that Mg in the supernatant is contained ²⁺And PO ₄ ^3-The molar ratio of (A) to (B) is 0.1 to 3.

Preferably, the bitter earth is added in step a, so that the added Mg ²⁺And PO ₄ ^3-The molar ratio of (A) to (B) is 2; and, in step b, adding dipotassium hydrogen phosphate to make Mg ²⁺And PO ₄ ^3-Is 1.

Preferably, the bitter earth is added in step a, so that the added Mg ²⁺And PO ₄ ^3-The molar ratio of (A) to (B) is 3; and, in step b, adding dipotassium hydrogen phosphate to make Mg ²⁺And PO ₄ ^3-Is 1.

Preferably, dibasic calcium phosphate is added in step a, so that Mg is added ²⁺And PO ₄ ^3-The molar ratio of (A) to (B) is 0.1; and, in step b, adding magnesium chloride to make Mg ²⁺And PO ₄ ^3-Is 1.

Preferably, dibasic calcium phosphate is added in step a, so that Mg is added ²⁺And PO ₄ ^3-The molar ratio of (A) to (B) is 0.3; and, in step b, adding magnesium chloride to make Mg ²⁺And PO ₄ ^3-Is 1.

Preferably, the bitter earth and dibasic calcium phosphate are added in step a, so that the added Mg ²⁺And PO ₄ ^3-The molar ratio of (A) to (B) is 1.5; and, in step b, adding dipotassium hydrogen phosphate to make Mg ²⁺And PO ₄ ^3-Is 1.

Preferably, the bitter earth and dibasic calcium phosphate are added in step a, so that the added Mg ²⁺And PO ₄ ^3-The molar ratio of (A) to (B) is 0.5; and, in step b, adding dipotassium hydrogen phosphate to make Mg ²⁺And PO ₄ ^3-Is 1.

Bitter soil: a mineral contains magnesium oxide as main ingredient.

The original piggery excrement treated by the method is directly taken from the piggery and is not treated.

The method can efficiently treat the pig farm manure, greatly improve the productivity of methane production by fermentation of the pig farm manure, greatly reduce the concentration of ammonia nitrogen in wastewater, and have certain ammonia nitrogen recovery (fertilizer production) capability. The method has simple reaction process and low cost, is suitable for large-scale industrial application and has good industrial application prospect.

Obviously, many modifications, substitutions, and variations are possible in light of the above teachings of the invention, without departing from the basic technical spirit of the invention, as defined by the following claims.

The present invention will be described in further detail with reference to the following examples. This should not be understood as limiting the scope of the above-described subject matter of the present invention to the following examples. All the technologies realized based on the above contents of the present invention belong to the scope of the present invention.

Detailed Description

The following examples are further illustrative, but the present invention is not limited to these examples.

The reagents and instruments used in the present invention are commercially available.

Example 1 method for solidifying manure in pig farm

a. Anaerobic fermentation

A reaction device: a full-automatic methane potential testing system;

the process comprises the following steps: taking the pig farm excrement, adding the pig farm excrement into a fermentation tank, inoculating activated sludge, and inoculating by an inoculation ratio r _I/S(inoculated sludge VS: pig farm manure VS) is 2, then bitter soil is added into the fermentation tank to lead Mg to be added ²⁺And PO ₄ ^3-The molar ratio of the fermentation liquor to the fermentation liquor is 2.0, anaerobic fermentation is carried out, after 20 to 30 days, the fermentation is finished, natural precipitation is carried out, and supernatant fluid 1 is obtained;

wherein, during anaerobic fermentation, the reaction temperature is controlled to be (37 +/-0.5) DEG C; introducing nitrogen for 2min to remove air above the liquid level before fermentation to create anaerobic environment; stirring once every 1h, wherein the stirring time is 5 min.

b. Adding plant ash into the supernatant 1, and adjusting pH to 9.0.

A reaction device: a 50mL beaker;

the process comprises the following steps: taking out 40mL of the supernatant obtained in the step a, putting the supernatant into a 50mL beaker, adding dipotassium hydrogen phosphate to ensure that the supernatant is Mg ²⁺And PO ₄ ^3-The molar ratio of the components is 1, the pH value of the mixture is adjusted to 9.0 by adding plant ash, and the mixture is naturally precipitated to obtain supernatant.

Second, detecting

1. Methane yield in anaerobic fermentation process

The ratio of methane was determined by gas chromatography and the results are given in the following table:

index (I)	Content (wt.)
		Cumulative gas production (mL)	1273.8
Percentage of methane (%)	64.6
		CO ₂Percent (%)	30.6
N ₂Percent (%)	4.8

From the above table, it can be seen that the cumulative gas production of methane was 1273.8mL, which is more than 2.7 times that of the comparative example. The methane content in the generated gas is 64.6%, and the methane content is high.

2.NH ₄ ⁺-N、Mg ²⁺And PO ₄ ^3-Variations of (2)

NH detection using a continuous flow analyzer ₄ ⁺-N content, inductively coupled plasma spectrometer Mg measurement ²⁺Content, determination of PO by ammonium molybdate spectrophotometry ₄ ^3-The results are given in the following table:

from the above table, it can be seen that Mg in the anaerobic digestion solution is added after the bitter soil is added in the anaerobic fermentation process ²⁺Concentration 364.6 mg/L15 times that of comparative example, NH ₄ ⁺-N concentration 781mg/L lower than that of comparative example, PO thereof ₄ ^3-The content is reduced by 53.9 percent, and a small amount of magnesium ammonium phosphate precipitate is formed in the fermentation process.

Adding dipotassium hydrogen phosphate into anaerobic digestion solution to obtain NH ₄ ⁺N is only 150.8Mg/L, but Mg in the supernatant ²⁺The content is reduced by 72.4 percent, and magnesium ammonium phosphate precipitate is formed.

The experimental result shows that the method can improve the methane yield of the anaerobic fermentation of the pig farm excrement by 2.7 times, and NH ₄ ⁺the-N removal effect is good, magnesium ammonium phosphate sediment can be formed, and the fertilizer preparation effect is good.

Embodiment 2 the method for preparing the fertilizer by solidifying the excrement and sewage in the pig farm

First, the method of the invention

a. Anaerobic fermentation

A reaction device: a full-automatic methane potential testing system;

the process comprises the following steps: taking the pig farm excrement, adding the pig farm excrement into a fermentation tank, inoculating activated sludge, and inoculating by an inoculation ratio r _I/S(inoculated sludge VS: pig farm manure VS) is 2, then bitter soil is added into the fermentation tank to lead Mg to be added ²⁺And PO ₄ ^3-The molar ratio of the fermentation liquor to the fermentation liquor is 3.0, anaerobic fermentation is carried out, after 20 to 30 days, the fermentation is finished, natural precipitation is carried out, and supernatant fluid 1 is obtained;

b. Adding plant ash into the supernatant 1, and adjusting pH to 9.0.

A reaction device: a 50mL beaker;

Second, detecting

1. Methane yield in anaerobic fermentation process

index (I)	Content (wt.)
		Cumulative gas production (mL)	304.3
Percentage of methane (%)	62.2
		CO ₂Percent (%)	29.3
N ₂Percent (%)	8.1

From the above table, it can be seen that the cumulative methane production was 304.3mL, which is 0.7 times more than that of the comparative example, and the methane production was low.

2.NH ₄ ⁺-N、Mg ²⁺And PO ₄ ^3-Variations of (2)

from the above table, it can be seen that Mg in the anaerobic digestion solution is added after the bitter soil is added in the anaerobic fermentation process ²⁺Concentration 548.0mg/L is 23 times that of comparative example, NH ₄ ⁺A concentration of 741.3mg/L of-N lower than in comparative example, PO ₄ ^3-The content is reduced by 63.1 percent, and a small amount of magnesium ammonium phosphate precipitate is formed in the fermentation process.

Adding dipotassium hydrogen phosphate into anaerobic digestion solution to obtain NH ₄ ⁺N is only 192.3Mg/L, but Mg in the supernatant ²⁺The content is reduced by 76.5 percent, and magnesium ammonium phosphate precipitate is formed. .

The experimental result shows that the method can reduce the methane yield in the anaerobic fermentation process, has good ammonia nitrogen removal effect, can form magnesium ammonium phosphate sediment, and has good fertilizer preparation effect.

Example 3 method for solidifying pig farm excrement and sewage to prepare fertilizer

a. Anaerobic fermentation

A reaction device: a full-automatic methane potential testing system;

the process comprises the following steps: taking the pig farm excrement, adding the pig farm excrement into a fermentation tank, inoculating activated sludge, and inoculating by an inoculation ratio r _I/S(inoculated sludge VS: pig farm manure VS) is 2, and calcium hydrophosphate is added into the fermentation tank to ensure that Mg is added ²⁺And PO ₄ ^3-The molar ratio of the raw materials is 0.3, anaerobic fermentation is carried out, after 20 to 30 days, the fermentation is finished, and natural precipitation is carried out to obtain supernatant fluid 1;

b. Adding plant ash into the supernatant 1, and adjusting pH to 9.0.

A reaction device: a 50mL beaker;

the process comprises the following steps: taking out 40mL of the supernatant obtained in the step a, putting the supernatant into a 50mL beaker, adding magnesium chloride to ensure that the magnesium chloride is Mg ²⁺And PO ₄ ^3-The molar ratio of the components is 1, the pH value of the mixture is adjusted to 9.0 by adding plant ash, and the mixture is naturally precipitated to obtain supernatant.

Second, detecting

1. Methane yield in anaerobic fermentation process

index (I)	Content (wt.)
		Cumulative gas production (mL)	1750.9
Percentage of methane (%)	60.6
		CO ₂Percent (%)	30.6
N ₂Percent (%)	8.8

From the above table, it can be seen that the cumulative gas production of methane was 1750.9mL, which is more than 3.7 times that of the comparative example. The methane content in the generated gas is 60.6%, and the content is high.

2.NH ₄ ⁺-N、Mg ²⁺And PO ₄ ^3-Variations of (2)

index (I)	Mixed liquor before fermentation	Anaerobic digestion solution	Adjusting pH and precipitating the resulting supernatant
				pH	7.2	7.4	9.0
NH ₄ ⁺-N(mg/L)	589.9	853.9	323.0
				Mg ²⁺(mg/L)	21.19	24.7	3.6
PO ₄ ^3-(mg/L)	159.9	84.6	3.8

From the above table, it can be seen that after adding calcium hydrogen phosphate in the anaerobic fermentation process, PO is added into the anaerobic digestion solution ₄ ^3-Concentration 84.6mg/L is 1.7 times that of comparative example, NH ₄ ⁺N concentration 853.9Mg/L higher than in the comparative example, Mg ²⁺The content ratio is basically unchanged, and the process does not form magnesium ammonium phosphate precipitate.

Adding magnesium chloride into anaerobic digestion solution, and then adding NH into the anaerobic digestion solution ₄ ⁺323.0mg/L of-N, PO ₄ ^3-The concentration drops by 95.5% and a small amount of struvite precipitate can form.

The experimental result shows that the method can improve the methane yield of the anaerobic fermentation of the pig farm excrement by 3.7 times, and NH ₄ ⁺the-N removal effect is poor, a small amount of magnesium ammonium phosphate precipitate can be formed, and the fertilizer preparation effect is poor.

Example 4 method for solidifying manure in pig farm

First, the method of the invention

a. Anaerobic fermentation

A reaction device: a full-automatic methane potential testing system;

the process comprises the following steps: taking the pig farm excrement, adding the pig farm excrement into a fermentation tank, and inoculating activated sludgeInoculation ratio r _I/S(inoculated sludge VS: pig farm manure VS) is 2, and calcium hydrophosphate is added into the fermentation tank to ensure that Mg is added ²⁺And PO ₄ ^3-Carrying out anaerobic fermentation at a molar ratio of 0.1 for 20-30 days, and then, finishing the fermentation and naturally precipitating to obtain supernatant fluid 1;

b. Adding plant ash into the supernatant 1, and adjusting pH to 9.0.

A reaction device: a 50mL beaker;

the process comprises the following steps: taking out 40mL of the supernatant obtained in the step a, putting the supernatant into a 50mL beaker, adding magnesium chloride to ensure that the magnesium chloride is Mg ²⁺And PO ₄ ^3-The molar ratio of the components is 1, the pH value is adjusted to 9.0, and the mixture is naturally precipitated to obtain supernatant.

Second, detecting

1. Methane yield in anaerobic fermentation process

index (I)	Content (wt.)
		Cumulative gas production (mL)	1415.4
Percentage of methane (%)	52.5
		CO ₂Percent (%)	26.8
N ₂Percent (%)	20.7

From the above table, it can be seen that the cumulative gas production of methane was 1415.4mL, which is more than 3.0 times that of the comparative example. The methane content in the generated gas is 52.5%, and the methane content is high.

2.NH ₄ ⁺-N、Mg ²⁺And PO ₄ ^3-Variations of (2)

from the above table, it can be seen that after adding calcium hydrogen phosphate in the anaerobic fermentation process, PO is added into the anaerobic digestion solution ₄ ^3-NH at a concentration of 100.1mg/L which is 2.1 times that of the comparative example ₄ ⁺N at a concentration of 853.9Mg/L higher than in the comparative example, with Mg ²⁺The comparative ratio is reduced by 46.4%.

Adding magnesium chloride into anaerobic digestion solution, and then adding NH into the anaerobic digestion solution ₄ ⁺-N is also 327.7mg/L, PO ₄ ^3-The concentration decreased by 91.1% and a small amount of struvite precipitate could form.

The experimental result shows that the method can improve the methane yield of the anaerobic fermentation of the pig farm excrement by 3.0 times, and NH ₄ ⁺the-N removal effect is poor, a small amount of magnesium ammonium phosphate precipitate can be formed, and the fertilizer preparation effect is poor.

Example 5 method for solidifying manure in pig farm

First, the method of the invention

a. Anaerobic fermentation

A reaction device: a full-automatic methane potential testing system;

the process comprises the following steps: taking the excrement, adding the excrement into a fermentation tank, inoculating activated sludge, and inoculating by an inoculation ratio r _I/S(inoculated sludge VS: pig farm manure VS) is 2, and then calcium hydrophosphate and bitter soil are added into the fermentation tank to lead Mg to be ²⁺And PO ^3-The molar ratio of the raw materials is 1.5, anaerobic fermentation is carried out, after 20 to 30 days, the fermentation is finished, natural precipitation is carried out, and supernate 1 is obtained;

b. Adding plant ash into the supernatant 1, and adjusting pH to 9.0.

A reaction device: a 50mL beaker;

Second, detecting

1. Methane yield in anaerobic fermentation process

index (I)	Content (wt.)
		Cumulative gas production (mL)	1808.0
Percentage of methane (%)	61.6
		CO ₂Percent (%)	34.3
N ₂Percent (%)	4.1

From the above table, it can be seen that the cumulative gas production of methane was 1808.0mL, which is more than 3.9 times that of the comparative example. The methane content in the generated gas is 61.6%, and the methane content is high.

2.NH ₄ ⁺-N、Mg ²⁺And PO ₄ ^3-Variations of (2)

NH analysis with continuous flow Analyzer ₄ ⁺-N content, inductively coupled plasma spectrometer Mg measurement ²⁺Content, determination of PO by ammonium molybdate spectrophotometry ₄ ^3-The results are given in the following table:

from the above table, it can be seen that after adding the magnesia and the calcium hydrogen phosphate simultaneously in the anaerobic fermentation process, Mg in the anaerobic digestion solution ²⁺A concentration of 271.4mg/L was 11 times that of comparative example, PO ₄ ^3-The concentration is 18.6mg/L, compared with the comparative example, the NH content is reduced by 61 percent ₄ ⁺The N concentration was 779.9mg/L, which is lower than the comparative example, and a small amount of magnesium ammonium phosphate precipitate was formed during the anaerobic fermentation.

Adding dipotassium hydrogen phosphate into anaerobic digestion liquid, adjusting pH value to 9.0, and adding NH into supernatant liquid of the anaerobic digestion liquid ₄ ⁺N is only 167.2mg/L, NH compared to comparative example ₄ ⁺A 58% decrease in-N; mg (magnesium) ²⁺The content of the magnesium ammonium phosphate is only 80.4mg/L, and magnesium ammonium phosphate precipitate can be formed.

The experimental result shows that the method can improve the methane yield of the anaerobic fermentation of the pig farm excrement and make the methane yield improved by 3.9 times. Regulating deviceAfter the pH value, NH in the supernatant ₄ ⁺The content of-N is only 167.2mg/L, and NH can be effectively removed ₄ ⁺And (4) N can form magnesium ammonium phosphate precipitate, and the fertilizer preparation effect is good.

Example 6 method for solidifying manure in pig farm

First, the method of the invention

a. Anaerobic fermentation

A reaction device: a full-automatic methane potential testing system;

the process comprises the following steps: taking the pig farm excrement, adding the pig farm excrement into a fermentation tank, inoculating activated sludge, and inoculating by an inoculation ratio r _I/S(inoculated sludge VS: pig farm manure VS) is 2, and then calcium hydrophosphate and bitter soil are added into the fermentation tank to lead Mg to be ²⁺And PO ₄ ^3-The molar ratio of the fermentation liquor to the fermentation liquor is 0.5, anaerobic fermentation is carried out, after 20 to 30 days, the fermentation is finished, natural precipitation is carried out, and supernatant fluid 1 is obtained;

b. Adding plant ash into the supernatant 1, and adjusting pH to 9.0.

A reaction device: a 50mL beaker;

the process comprises the following steps: taking out 40mL of the supernatant obtained in the step a, putting the supernatant into a 50mL beaker, adding dipotassium hydrogen phosphate to ensure that the supernatant is Mg ²⁺And PO ₄ ^3-The molar ratio of the components is 1, the pH value is adjusted to 9.0, and the mixture is naturally precipitated to obtain supernatant.

Second, detecting

1. Methane yield in anaerobic fermentation process

index (I)	Content (wt.)
		Cumulative gas production (mL)	936.5
Percentage of methane (%)	58.75
		CO ₂Percent (%)	28.27
N ₂Percent (%)	12.98

From the above table, it can be seen that the cumulative gas production of methane was 936.5mL, which is more than 2.0 times that of the comparative example. The methane content in the generated gas is 58.75%, and the methane content is high.

2.NH ₄ ⁺-N、Mg ²⁺And PO ₄ ^3-Variations of (2)

from the above table, it can be seen that after adding the magnesia and the calcium hydrogen phosphate simultaneously in the anaerobic fermentation process, Mg in the anaerobic digestion solution ²⁺A concentration of 425.5mg/L is 17.9 times that of the comparative example, PO ₄ ^3-The concentration is 16.6mg/L, compared with the comparative example, the NH content is reduced by 65 percent ₄ ⁺The N concentration was 690.1mg/L, which is lower than the comparative example, and more struvite precipitate was formed during the anaerobic fermentation.

Adding dipotassium hydrogen phosphate into anaerobic digestion liquid, adjusting pH value to 9.0, and adding NH into supernatant liquid of the anaerobic digestion liquid ₄ ⁺N is only 98.4mg/L, NH compared to comparative example ₄ ⁺N decreased by 75%; mg (magnesium) ²⁺The content was only 78.5mg/L, and a large amount of struvite precipitate could be formed.

The experimental result shows that the method can improve the methane yield of the anaerobic fermentation of the pig farm excrement and cause the methane yield to be improved by 2.0 times. After adjusting the pH value, NH ₄ ⁺The removal rate of-N is high, more magnesium ammonium phosphate precipitates are formed, and the magnesium ammonium phosphate can be used as a compound fertilizer, so that the economic benefit is improved.

Comparative example

In the steps a and b, magnesia and calcium hydrophosphate are not added.

1. Methane yield in anaerobic fermentation process

index (I)	Content (wt.)
		Cumulative gas production (mL)	470.0
Percentage of methane (%)	50.8
		CO ₂Percent (%)	28.4
N ₂Percent (%)	20.9

As can be seen from the above table, the cumulative gas production of methane is only 470.0mL, and the methane content in the gas is only 50.8%.

2.NH ₄ ⁺-N、Mg ²⁺And PO ₄ ^3-Variations of (2)

from the above table it can be seen that in the comparative example, NH was added after adjusting the pH to 9.0 ₄ ⁺N400.1 Mg/L, Mg ²⁺And PO ₄ ^3-There is substantially no change.

In conclusion, the proper addition of the bitter soil and the calcium hydrogen phosphate in the process of the anaerobic fermentation of the excrement in the pig farm can improve the methane yield and reduce NH in the anaerobic digestion liquid of the bitter soil ₄ ⁺-N content. The bitter soil and the calcium hydrophosphate are added simultaneously in the anaerobic fermentation process, so that magnesium ammonium phosphate precipitate, Mg ²⁺And PO ₄ ^3-In a molar ratio of 0.5, more magnesium ammonium phosphate precipitate, NH ₄ ⁺the-N removal rate is higher.

The method provides a new, efficient and low-cost pig farm manure treatment method, improves the methane yield, simultaneously removes ammonia nitrogen, solidifies the ammonia nitrogen to prepare fertilizer, and has a good application prospect.

Claims

1. A livestock and poultry manure treatment method is characterized by comprising the following steps: the method comprises the following steps:

a. taking pig farm feces, inoculating activated sludge, performing anaerobic fermentation, simultaneously or respectively adding bitter soil and calcium hydrogen phosphate into a fermentation tank, fermenting for 20-30 days, and naturally precipitating to obtain supernatant 1;

2. The process of claim 1, wherein the manure is pig farm manure.

3. The method of claim 1, wherein step b is adjusting the pH with plant ash.

And/or, step b adjusts the pH to 9.0.

4. The method of claim 1, wherein: in step b, magnesium chloride or dipotassium hydrogen phosphate is added into the supernatant liquid 1 to ensure that Mg in the supernatant liquid ²⁺And PO ₄ ^3-The molar ratio of (a) to (b) is 1.

5. The method of claim 1, wherein: adding magnesia and calcium hydrogen phosphate in the step a to ensure that the added Mg ²⁺And PO ₄ ^3-The molar ratio of (A) to (B) is 0.1 to 3.

6. A process according to any one of claims 1 to 4, wherein in step a, magnesia is added so that Mg is added ²⁺And PO ₄ ^3-The molar ratio of (A) to (B) is 2;

and, in step b, adding dipotassium hydrogen phosphate to make Mg ²⁺And PO ₄ ^3-Is 1.

7. A process according to any one of claims 1 to 4, wherein in step a, magnesia is added so that Mg is added ²⁺And PO ₄ ^3-The molar ratio of (A) to (B) is 3;

and, in step b, potassium dihydrogen phosphate is added to make Mg ²⁺And PO ₄ ^3-Is 1.

8. The method according to any one of claims 1 to 4, whereinIn step a, calcium hydrogen phosphate is added to make Mg added ²⁺And PO ₄ ^3-The molar ratio of (A) to (B) is 0.1;

and, in step b, adding magnesium chloride to make Mg ²⁺And PO ₄ ^3-Is 1.

9. A process according to any one of claims 1 to 4, characterized in that dibasic calcium phosphate is added in step a, so that Mg is added ²⁺And PO ₄ ^3-The molar ratio of (A) to (B) is 0.3;

and, in step b, adding magnesium chloride to make Mg ²⁺And PO ₄ ^3-Is 1.

10. A process according to any one of claims 1 to 4, wherein in step a, magnesia and dibasic calcium phosphate are added, such that Mg is added ²⁺And PO ₄ ^3-The molar ratio of (A) to (B) is 1.5; and, in step b, adding dipotassium hydrogen phosphate to make Mg ²⁺And PO ₄ ^3-Is 1;

or, adding bitter earth and calcium hydrogen phosphate in the step a, so that the added Mg ²⁺And PO ₄ ^3-The molar ratio of (A) to (B) is 0.5;