A method for deodorizing the composting process and its application

Abstract

The present invention discloses a method for deodorizing in the composting process and its application, belonging to the technical field of environmental pollution of organic solid waste resources. In order to effectively provide a method for removing odors in fecal compost and sewage compost. The present invention provides a method for deodorizing in the composting process, adding 2-(aminooxy)acetic acid for fermentation reaction during the composting process. The present invention solves the problem of synergistic emission reduction of hydrogen sulfide and ammonia in aerobic composting from the source, reduces the loss of nitrogen and sulfur elements in the compost, and effectively improves the fertilizer efficiency of the compost finished product.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmental pollution of organic solid waste resources, and specifically relates to a method for deodorizing in the composting process and its application. Background Technique

[0002] During the sewage treatment process, a large amount of sludge will be generated. At present, the daily sewage treatment scale in China exceeds 200 million tons, and the annual output of activated sludge (with a moisture content of 80%) exceeds 60 million tons. According to relevant data calculations, in 2025, the annual sludge output in China is expected to exceed 100 million tons. The generated sludge not only occupies a large amount of land, causing environmental pollution, but also imposes a heavy burden on sewage treatment plants. And sludge composting is a good improvement method. Nowadays, a large amount of sludge waste can be treated resourcefully and harmlessly through composting and converted into stable fertilizers. This can not only increase organic matter, improve the soil structure, promote agricultural production increase, but also turn sludge into treasure and solve the problems of large-scale generation and stacking of sludge. However, there will also be some negative impacts during the composting process, such as the emission of malodorous gases. Research shows that the malodorous gases generated during the composting process are mainly hydrogen sulfide and ammonia. The emission of these gases will not only cause great losses of nitrogen and sulfur elements in the fermentation products, leading to a decline in fertility, but also cause secondary pollution to the ecological environment. The sulfur and nitrogen content in sludge is extremely high. If not properly treated, it will cause serious consequences for environmental pollution and human health. Therefore, inhibiting the emission of malodorous gases during the aerobic composting process of sludge is of great significance for protecting the ecological environment and improving its resource utilization rate.

[0003] In recent years, the mainstream methods for removing hydrogen sulfide and ammonia generated during the composting process are through biological filtration, chelating solution adsorption, etc. However, these methods only adsorb and dispose of the already generated gases and cannot reduce the generation of malodorous gases from the source. Regarding the problem of reducing the generation of hydrogen sulfide and ammonia at the source in compost, on the one hand, the parameters of the internal source in the compost can be optimized by adjusting the carbon-nitrogen ratio, aeration rate, and controlling the initial moisture content of the compost pile. On the other hand, the addition of exogenous substances can promote or inhibit the relevant physical, chemical, and biological reactions during the composting process. On the premise of ensuring the optimal parameters of each part of the compost pile, the use of coupled exogenous substance additives is the key method currently under research. However, since hydrogen sulfide and ammonia are acidic and alkaline gases respectively, with different characteristics, different physical or chemical additives are needed to separately treat the emissions of hydrogen sulfide and ammonia. Although this method is targeted, in the actual operation process, due to the possible contradictory relationship between the treatment of the two malodorous gases, it needs to be carried out in stages to prevent the mutual cancellation effect caused by improper treatment. In addition, considering the potential complexity of the compost environment and the variability of the microbial community, generally, inoculating a composite microbial inoculant is used to affect nitrogen and sulfur metabolism, thereby reducing the emissions of hydrogen sulfide and ammonia. However, the stability of the inoculant during the application process will also become a problem faced in production. Therefore, when using a composite microbial inoculant, additional measures must be taken to ensure its long-term and stable effect, otherwise, no obvious emission reduction effect may be seen in the short term. In summary, regarding the problem of reducing the emissions of hydrogen sulfide and ammonia generated during the composting process, although certain progress has been made in the existing technical means, further research and improvement are still needed. Only in this way can the quality of the compost product be ensured, the environment be protected, and the ecological balance be maintained. Summary of the Invention

[0004] The purpose of the present invention is to effectively provide a method for removing odors from fecal compost and sewage compost.

[0005] The present invention provides a method for deodorizing during the composting process, adding 2-(aminooxy)acetic acid during the composting process for fermentation reaction.

[0006] Further defined, the mass ratio of the added 2-(aminooxy)acetic acid to the compost material is 0.01% - 0.02%.

[0007] Further defined, the compost material is one or a mixture of livestock and poultry manure, straw, or dehydrated sludge generated by a sewage treatment plant meeting the requirements of agricultural sludge.

[0008] Further defined, the composting method is to select sludge for aerobic composting, use sawdust as a carbon source, and adjust the C / N ratio for fermentation.

[0009] Further limit that the initial C / N of the compost is adjusted to 25 before the fermentation starts.

[0010] Further limit that the initial moisture content is adjusted to 70%.

[0011] Further limit that the aeration volume of the fermentation reaction is maintained at 0.5 L / min, and the aeration time is 5 - 8 hours.

[0012] Further limit that the judgment criterion for the termination of composting is: when the germination index exceeds 80%, the compost product is completely decomposed and the composting stops.

[0013] The present invention provides an application of the above - mentioned method in inhibiting the generation of hydrogen sulfide and ammonia.

[0014] The present invention provides an application of the above - mentioned method in inhibiting the generation of odors in composting.

[0015] Beneficial effects: By directionally regulating the metabolism of compost microorganisms to inhibit the generation of hydrogen sulfide and ammonia, that is, adding 2 - (aminooxy)acetic acid to directionally regulate the endogenous sulfur metabolism process in sludge composting, thereby inhibiting the generation of hydrogen sulfide and ammonia from the source, reducing the release amount of hydrogen sulfide and ammonia in the sludge aerobic fermentation process, and thus reducing the loss of nitrogen and sulfur elements. Based on inhibiting the pathway of compost microorganisms synthesizing hydrogen sulfide with cysteine as a substrate, this method applies 2 - (aminooxy)acetic acid as a biological inhibitor to the sludge composting process, solves the problem of synergistic emission reduction of hydrogen sulfide and ammonia in aerobic composting from the source, reduces the loss of nitrogen and sulfur elements in composting, and effectively improves the fertilizer efficiency of the compost finished product. Description of the Drawings

[0016] Figure 1 For Example 1, the release amount (a) and cumulative release amount (b) of hydrogen sulfide in the sludge aerobic composting with the addition of 2 - (aminooxy)acetic acid and the control group;

[0017] Figure 2 For Example 2, the release amount (a) and cumulative release amount (b) of hydrogen sulfide in the chicken manure aerobic composting with the addition of 2 - (aminooxy)acetic acid and the control group;

[0018] Figure 3 For Example 3, the release amount (a) and cumulative release amount (b) of ammonia in the sludge aerobic composting with the addition of 2 - (aminooxy)acetic acid and the control group;

[0019] Figure 4 For Example 4, the release amount (a) and cumulative release amount (b) of ammonia in the chicken manure aerobic composting with the addition of 2 - (aminooxy)acetic acid and the control group. Detailed Embodiments

[0020] 2-(Aminooxy)acetic acid: Catalog number A885053, brand Macklin, abbreviation AOAA.

[0021] Example 1: Application of 2-(Aminooxy)acetic acid in inhibiting hydrogen sulfide emission during aerobic sludge composting

[0022] In this experiment, various organic solid wastes were selected for testing to explore the ability of waste to inhibit hydrogen sulfide generation during sludge composting.

[0023] The composting experiment used sludge waste and sawdust as raw materials, which were taken from surrounding villages and towns in Harbin.

[0024] Fresh sludge was set aside; sawdust was selected as the carbon source and set aside; the enzyme inhibitor 2-(aminooxy)acetic acid was purchased, and 2-(aminooxy)acetic acid was weighed and dissolved in a spray bottle for later use.

[0025] I. Respectively take 1.6 kg of sludge, and use sawdust to adjust the carbon-nitrogen ratio (C / N, which is the ratio of organic matter content (%) to total nitrogen content (%)) of the initial composting material to 25, adjust the initial moisture content to 70%, and maintain this moisture condition throughout the composting process.

[0026] The experiment was set up with a total of one treatment group. One group was sludge composting; one group was sludge composting + 0.01% inhibitor, and two parallels were set for each treatment.

[0027] II. Evenly spray the dissolved 2-(aminooxy)acetic acid on the surface of the sludge in the experimental group of Step I, mix evenly, and place the mixed material in a fermentation bottle.

[0028] III. During the sludge composting process, ventilate for 8 h every day, and keep the ventilation volume of the fermentation reaction at 0.5 L / min. Since the hydrogen sulfide gas emission mainly occurs in the first 14 days of composting, this composting lasted for 14 days until the hydrogen sulfide release amount was 0;

[0029] IV. Use a portable hydrogen sulfide measuring instrument to regularly measure and record the hydrogen sulfide and ammonia production in the reactor every day, and calculate the cumulative hydrogen sulfide amount and cumulative production reduction rate generated in different treatment groups during composting. The calculation formulas are as follows:

[0030]

[0031] The experimental results are shown in Figure 1 , this example proves that adding 0.01% of 2-(aminooxy)acetic acid during sludge composting can significantly reduce the daily hydrogen sulfide gas release amount. After 14 days of composting, compared with the control group, the hydrogen sulfide production in the sludge treatment group decreased by 25.63%. 2-(Aminooxy)acetic acid played a good role in sludge composting.

[0032] Example 2: Inhibition of hydrogen sulfide emission by 2-(aminooxy)acetic acid during aerobic composting of chicken manure

[0033] In this experiment, a variety of organic solid wastes were selected for testing to explore the ability of waste to inhibit hydrogen sulfide generation during chicken manure composting.

[0034] The composting experiment used chicken manure waste and sawdust as the original materials, which were taken from surrounding villages and towns in Harbin.

[0035] The fresh chicken manure was naturally air-dried to remove impurities such as hair in the feces and set aside; sawdust was selected as the carbon source and set aside; the enzyme inhibitor 2-(aminooxy)acetic acid was purchased, and 2-(aminooxy)acetic acid was weighed and dissolved in a spray bottle for later use.

[0036] I. Take 600 g of chicken manure respectively, and use sawdust to adjust the carbon-nitrogen ratio (C / N, which is the ratio of organic matter content (%) to total nitrogen content (%)) of the initial composting materials to 25, adjust the initial moisture content to 70%, and maintain this moisture condition throughout the composting process.

[0037] A total of one treatment group was set up in the experiment. One group was normal chicken manure; one group was chicken manure compost + 0.02% inhibitor, and two parallels were set for each treatment.

[0038] II. The dissolved 2-(aminooxy)acetic acid was evenly sprayed on the surface of the chicken manure in the experimental group of step I, mixed evenly, and the mixed materials were placed in a fermentation bottle.

[0039] III. During the chicken manure composting process, aeration was carried out for 5 h every day, and the aeration volume of the fermentation reaction was maintained at 0.5 L / min. Since the hydrogen sulfide gas emission mainly occurred in the first 16 days of composting, this composting lasted for 25 days until the hydrogen sulfide release amount was 0. The compost was regularly turned during the composting process to supplement water.

[0040] IV. Use a portable hydrogen sulfide measuring instrument to regularly measure and record the hydrogen sulfide and ammonia production in the reactor every day, and calculate the cumulative hydrogen sulfide production and the cumulative production reduction rate generated by different treatment groups during composting. The calculation formulas are as follows:

[0041]

[0042] The experimental results are shown in Figure 2 , this example proves that the cumulative hydrogen sulfide production of the chicken manure treatment group decreased by 29.69% in 16 days, and 2-(aminooxy)acetic acid played a good role in chicken manure composting.

[0043] Example 3: Application of 2-(aminooxy)acetic acid in inhibiting ammonia emission during aerobic composting of sludge

[0044] In this experiment, a variety of organic solid wastes were selected for testing to explore the ability of waste to inhibit hydrogen sulfide generation during sludge composting.

[0045] The composting experiment used sludge waste and sawdust as the original materials, which were taken from surrounding villages and towns in Harbin.

[0046] Fresh sludge was set aside; sawdust was selected as the carbon source and set aside; the enzyme inhibitor 2-(aminooxy)acetic acid was purchased, and 2-(aminooxy)acetic acid was weighed and dissolved in a spray bottle for later use.

[0047] I. Respectively take 1.6 kg of sludge, and use sawdust to adjust the carbon-nitrogen ratio (C / N, which is the ratio of organic matter content (%) to total nitrogen content (%)) of the initial composting materials to 25, adjust the initial moisture content to 70%, and maintain this moisture condition throughout the composting process.

[0048] The experiment was set up with a total of one treatment group. One group was sludge composting; one group was sludge composting + 0.01% inhibitor, and two parallels were set for each treatment.

[0049] II. The dissolved 2-(aminooxy)acetic acid was evenly sprayed on the surface of the sludge in the experimental group of Step I, mixed evenly, and the mixed materials were placed in a fermentation bottle.

[0050] III. During the sludge composting process, aeration was carried out for 8 hours every day, and the aeration volume of the fermentation reaction was maintained at 0.5 L / min. Since the hydrogen sulfide gas emission mainly occurred in the first 14 days of composting, this composting lasted for 14 days until the hydrogen sulfide release amount was 0;

[0051] IV. Use a portable hydrogen sulfide measuring instrument to regularly measure and record the hydrogen sulfide and ammonia production in the reactor every day, and calculate the cumulative hydrogen sulfide production and the cumulative production reduction rate generated by different treatment groups during composting. The calculation formula is as follows:

[0052]

[0053] In Step IV, use a portable ammonia measuring instrument, and the rest of the operations remain unchanged.

[0054] The experimental results are shown in Figure 3 This experimental example proves that adding 0.01% of 2-(aminooxy)acetic acid can significantly reduce the daily ammonia gas release amount. After 14 days of composting, compared with the control group, the cumulative ammonia production of the sludge treatment group decreased by 7.79%. This indicates that the application of 2-(aminooxy)acetic acid in sludge aerobic composting can not only inhibit hydrogen sulfide emission but also inhibit ammonia emission, which helps to reduce nitrogen loss and improve the nitrogen fixation rate of compost.

[0055] Example 4: Application of 2-(aminooxy)acetic acid in inhibiting ammonia emission during chicken manure aerobic composting

[0056] In this experiment, a variety of organic solid wastes were selected for testing to explore the ability of waste to inhibit hydrogen sulfide generation during chicken manure composting.

[0057] The composting experiment used chicken manure waste and sawdust as the original materials, which were taken from surrounding villages and towns in Harbin.

[0058] The fresh chicken manure was naturally air-dried to remove impurities such as hair in the manure and reserved; sawdust was selected as the carbon source and reserved; the enzyme inhibitor 2-(aminooxy)acetic acid was purchased, and 2-(aminooxy)acetic acid was weighed and dissolved in a spray bottle for later use.

[0059] I. Take 600 g of chicken manure respectively, and use sawdust to adjust the carbon-nitrogen ratio (C / N, which is the ratio of organic matter content (%) to total nitrogen content (%)) of the initial composting materials to 25, adjust the initial moisture content to 70%, and maintain this moisture condition throughout the composting process.

[0060] The experiment was set up with a total of one treatment group. One group was normal chicken manure; one group was chicken manure compost + 0.02% inhibitor, and two parallels were set for each treatment.

[0061] II. Evenly spray the dissolved 2-(aminooxy)acetic acid on the surface of the chicken manure in the experimental group of Step I, mix evenly, and place the mixed materials in a fermentation bottle.

[0062] III. Ventilate for 5 h every day during the chicken manure composting process, and keep the ventilation volume of the fermentation reaction at 0.5 L / min. Since the hydrogen sulfide gas emission mainly occurs in the first 16 days of composting, this composting lasted for 25 days until the hydrogen sulfide release amount was 0. During the composting process, turn the pile regularly and supplement water.

[0063] IV. Use a portable hydrogen sulfide measuring instrument to regularly measure and record the hydrogen sulfide and ammonia production in the reactor every day, and calculate the cumulative hydrogen sulfide production and cumulative production reduction rate generated by different treatment groups during composting. The calculation formulas are as follows:

[0064]

[0065] Use a portable ammonia measuring instrument in Step IV, and keep the rest of the operations unchanged.

[0066] The experimental results are shown in Figure 4 This experimental example proves that adding 0.02% of 2-(aminooxy)acetic acid can significantly reduce the daily ammonia gas release amount. After 16 days of composting, compared with the control group, the cumulative ammonia production of the chicken manure treatment group decreased by 56.92%. This shows that 2-(aminooxy)acetic acid can not only inhibit hydrogen sulfide emission but also inhibit ammonia emission during the aerobic composting of chicken manure, which helps to reduce nitrogen loss and improve the nitrogen fixation rate of compost.

Claims

1. A method for deodorizing a composting process, characterized in that: 2-(aminooxy)acetic acid is added during the composting process for fermentation reaction; the amount of 2-(aminooxy)acetic acid added accounts for 0.01%-0.02% of the mass ratio of the composting material; the compost is sludge aerobic composting; and the deodorization is to remove hydrogen sulfide and ammonia.

2. The method according to claim 1, characterized in that The compost material is dewatered sludge produced by a sewage treatment plant that meets the requirements for agricultural sludge.

3. The method according to claim 1, characterized in that The composting method is to select sludge for aerobic composting, take sawdust as a carbon source, and adjust the C / N ratio for fermentation.

4. The method according to claim 3, characterized in that Before fermentation begins, adjust the initial compost C / N to 25.

5. The method according to claim 3, characterized in that: The initial moisture content was adjusted to 70%.

6. The method according to claim 1, characterized in that The aeration volume of the fermentation reaction was maintained at 0.5 L / min, and the aeration time was 5-8 hours.

7. The method according to claim 1, characterized in that The criterion for the termination of composting is: when the germination index exceeds 80%, the compost product is fully mature and composting stops.

8. Use of the method according to any one of claims 1 to 7 in suppressing the generation of odor in composting.

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