Inoculum domestication method for relieving acid or ammonia nitrogen inhibition of anaerobic fermentation system

Abstract

The invention provides an inoculum domestication method for relieving acid or ammonia nitrogen inhibition of an anaerobic fermentation system, which comprises the following steps of: carrying out constant-temperature anaerobic fermentation culture at medium temperature (30-35 DEG C) or high temperature (50-55 DEG C) until the gas yield is stable by taking livestock manure, activated sludge, industrial anaerobic digestion residues or mineralized refuse biogas fermentation liquor and the like as inoculums; the obtained inoculum is an inoculum which has relatively strong acid tolerance or ammonia nitrogen tolerance after domestication. The domesticated inoculum with good tolerance and the original untreated inoculum are mixed according to a certain proportion and then put into an anaerobic fermentation system, and wet fermentation (TS = 5-10% and total solid content) or dry fermentation (TS = 20-30%) is carried out, so that the pH value of the anaerobic fermentation system is recovered to a state suitable for growth of methanogens.

Description

Technical Field

[0001] The invention belongs to the technical field of agricultural solid waste resource utilization and anaerobic fermentation, and specifically relates to an inoculum acclimation method for relieving acid or ammonia nitrogen inhibition in an anaerobic fermentation system. Background Art

[0002] Under the current background of green and low-carbon development, the treatment and resource utilization of agricultural biomass waste materials such as crop straw and livestock and poultry manure has become an important issue. As an effective way of resource utilization, anaerobic fermentation can convert organic matter in agricultural waste into biogas, and the produced biogas residues and liquid biogas can also be used as high-quality fertilizers. However, excessive accumulation of anaerobic fermentation intermediates usually leads to acidification or high concentrations of ammonia nitrogen in the system, which is usually an important reason restricting the long-term stable operation of anaerobic fermentation systems. This problem is particularly obvious when the organic load of the fermentation system is too high or the C / N ratio of the raw materials is unbalanced.

[0003] In the anaerobic fermentation process, the characteristics of the raw materials have a significant impact on the fermentation effect. Carbon-rich organic wastes such as crop straw and agricultural waste are easily degraded by microorganisms due to the rich carbohydrates and proteins in the raw materials, resulting in the rapid accumulation of volatile fatty acids (VFA), which in turn causes acid inhibition, leading to a rapid decrease in the activity of methanogens and a rapid decrease in gas production. Nitrogen-rich organic wastes such as poultry and livestock manure and kitchen waste are ultimately converted into ammonia nitrogen (including free ammonia NH 3 and NH 4+ ), when the cumulative concentration is too high, it will inhibit the activity of methanogens and affect the anaerobic fermentation process. In order to improve the efficiency of anaerobic fermentation, it is necessary to reduce the inhibition phenomenon through appropriate pretreatment and control measures to ensure the recovery of the gas production function of the anaerobic fermentation system.

[0004] At present, when acid inhibition or ammonia inhibition occurs in anaerobic fermentation systems, physical, chemical and biological means are usually used to recover. Physical methods involve adjusting operating conditions such as temperature, pH and agitation to optimize the physiological state of microorganisms. Chemical methods include adding alkaline substances such as sodium bicarbonate to neutralize accumulated acids, or using chemicals to reduce ammonia nitrogen concentrations. Biological methods focus on the adjustment of microbial communities, such as introducing microorganisms that can tolerate or transform inhibitory substances, or improving the tolerance of existing microorganisms through domestication. Summary of the invention

[0005] The object of the present invention is to provide an inoculum acclimation method for relieving acid or ammonia nitrogen inhibition in an anaerobic fermentation system, which can effectively alleviate the acid / ammonia inhibition in the anaerobic fermentation system and quickly restore the anaerobic fermentation system.

[0006] The principle of the present invention is to add a certain proportion of domesticated inoculum to the original inoculum to change the microbial diversity and population structure in the anaerobic fermentation system, greatly improve the relative abundance of Firmicutes, Bacteroidetes and other bacterial communities during the acid production period of anaerobic fermentation, and the rich hydrolytic bacteria and acid-producing bacteria play an important role in degrading the acidic substances / ammonia nitrogen substances accumulated in the fermentation system, which helps the anaerobic fermentation system to quickly recover to a state suitable for the growth of methanogenic bacteria, and the effect is better than using only domesticated inoculum or original inoculum.

[0007] In order to achieve the above-mentioned purpose, specifically, the present invention adopts the following technical scheme: an inoculum acclimation method for relieving acid or ammonia nitrogen inhibition in an anaerobic fermentation system, comprising: using biomass degradable raw materials as anaerobic fermentation substrates, and adding the inoculum with good tolerance after acclimation and the original untreated inoculum into the anaerobic fermentation system in a certain mixing ratio to carry out wet anaerobic fermentation or dry anaerobic fermentation, wherein the preparation of the inoculum with good tolerance after acclimation comprises: culturing poultry and livestock manure, activated sludge, industrial anaerobic digestion residues, mineralized garbage or biogas fermentation liquid at a medium temperature of 30-35°C or a high temperature of 50-55°C in a constant temperature anaerobic fermentation system until the gas production is stable, so as to obtain the inoculum with good tolerance after acclimation.

[0008] In the above technical solution, the mixing ratio of the domesticated inoculant with good tolerance and the original untreated inoculant is 1:1.

[0009] In the above technical solution, the original untreated inoculum is livestock manure, activated sludge, industrial anaerobic digestion residue, mineralized garbage or biogas fermentation liquid.

[0010] In the above technical solution, the anaerobic fermentation substrate includes crop straw waste and forestry waste.

[0011] In the above technical solution, the dry matter content of the wet anaerobic fermentation TS=5-10%, or the dry matter content of the dry anaerobic fermentation TS=20-30%.

[0012] The advantages of the present invention are mainly reflected in the following aspects: the inoculum acclimation method has the characteristics of simple operation, low cost, no environmental pollution, and improved microbial tolerance and fermentation gas production efficiency. (1) Simple operation and low cost; (2) High feasibility and significant effect; (3) Can effectively alleviate the acid / ammonia inhibition of the anaerobic fermentation system and quickly restore the anaerobic fermentation system.

[0013] Compared with the prior art, the beneficial effect of the present invention is that adding the domesticated inoculum to the original inoculum, and the domestication conditions are medium temperature (30-35°C) or high temperature (50-55°C) constant temperature cultivation until the gas production is stable, which can improve the activity and diversity of microorganisms, help to quickly start the gas production process during anaerobic fermentation, and increase the gas production, overcoming the prior art view that: using all domesticated inoculum is more conducive to the anaerobic fermentation system to quickly recover to a state suitable for the growth of methanogenic bacteria.

[0014] The experiment unexpectedly found that due to the high solid content and poor fluidity of the materials in the anaerobic fermentation with biomass degradable raw materials as substrates, the inoculation operation is crucial for the smooth progress of the fermentation. The appropriate inoculation amount of the domesticated inoculum (not all domesticated inoculum) can not only ensure the smooth start of the reaction, but also take into account the material gas production rate and volumetric gas production rate, thereby improving the stability of the entire anaerobic fermentation system. The present invention uses dry anaerobic fermentation dry matter content TS = 20-30% or wet anaerobic fermentation dry matter content TS = 5-10%, which can improve the mass transfer process, accelerate the start-up speed of the anaerobic fermentation reaction, shorten the fermentation cycle, and thus improve the system's operating stability and gas production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solution of the present invention, the drawings involved in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the description are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 The effect of three inoculants on the pH of corn stover wet fermentation under acid inhibition; Figure 2 The effect of three inoculants on daily gas production of corn stover wet fermentation under acid inhibition; Figure 3 The effects of three inoculants on the cumulative gas production of corn stover wet fermentation under acid inhibition; Figure 4 The effect of three inoculants on the pH of corn stover dry fermentation under acid inhibition; Figure 5 The effect of three inoculants on daily gas production of corn stover dry fermentation under acid inhibition; Figure 6 The effects of three inoculants on the cumulative gas production of corn stover dry fermentation under acid inhibition; Figure 7 The effect of three inoculants on the pH of corn stover wet fermentation under ammonia nitrogen inhibition; Figure 8The effect of three inoculants on the daily gas production of corn straw wet fermentation under ammonia nitrogen inhibition; Fig. 9 The effects of three inoculants on the cumulative gas production of corn straw wet fermentation under ammonia nitrogen inhibition; Fig.10 The effects of three inoculants on the pH of corn stover dry fermentation under ammonia nitrogen inhibition; Fig.11 The effect of three inoculants on daily gas production of corn stover dry fermentation under ammonia nitrogen inhibition; Fig.12 This is the effect of three inoculants on the cumulative gas production of dry fermentation of corn straw under ammonia nitrogen inhibition. DETAILED DESCRIPTION

[0017] The technical scheme of the present invention is described below in conjunction with the embodiments, but the present invention is not limited to the following embodiments. The experimental methods and detection methods described in each embodiment are conventional methods unless otherwise specified; the reagents and materials described are all commercially available unless otherwise specified.

[0018] Example 1: This example provides the effect of inoculum acclimation on the changes of various indicators under acid inhibition during wet anaerobic fermentation of corn straw.

[0019] 1. Raw material collection and processing Corn stalks and cow dung were collected as experimental raw materials (in a certain area of ​​Shaanxi Province). The corn stalks were naturally air-dried until their moisture content was less than 10%. They were then crushed and passed through a 20-mesh sieve and stored in a sealed and dry condition at room temperature for later use.

[0020] The inoculum used is cow dung, and the inoculum preparation method is as follows: first, the retrieved cow dung is cultured anaerobically at a constant temperature of about 30 days at a medium temperature (30-35°C) or a high temperature (50-55°C) until the gas production returns to a stable level, which means the acclimation is complete; then, it is evenly mixed with unacclimated original cow dung in a mass ratio of 0:1, 1:1 or 1:0 to obtain three types of cow dung inocula.

[0021] 2. Anaerobic fermentation experiment The experiment set up 3 experimental groups: the three kinds of cow dung inocula were added into the mixed fermentation system respectively, and the fermentation system substrate was the corn stalks mentioned above. Each experimental group was set up with 3 replicates.

[0022] Corn stalks and cow dung were mixed evenly, the inoculation amount of cow dung (based on the inoculation ratio) was 30%, and the fermentation TS was 8% (wet). Water was added to the effective volume and mixed evenly, and N was introduced into the anaerobic fermentation reactor. 2 (at least 1 min) to replace the gas in the upper space of the fermentation reactor to achieve an anaerobic reaction environment.

[0023] A 150 mL feeding bottle was used as the anaerobic fermentation reactor, with an effective reaction volume of 100 mL and a fermentation temperature of 35°C. Three inoculation ratios of cow dung were added to the anaerobic fermentation system and mixed thoroughly for wet anaerobic fermentation. The fermentation reactor was fully stirred once every 24 h, and pH was measured, fermentation gas was collected, and gas production volume was measured every 48 h. The cumulative gas production of each test group was counted until the gas production stopped.

[0024] Experimental results: Figure 1 The effect of three inoculants on pH in the wet fermentation system of corn straw under acid inhibition. In the early stage of the reaction, organic matter was hydrolyzed into VFA by hydrolytic bacteria, while methanogenic archaea had a certain adaptation period to organic solid waste raw materials. At this time, the growth rate of hydrolytic bacteria was greater than that of methanogenic archaea, acid accumulation occurred, and the pH value decreased accordingly. On the second day, the pH dropped to the lowest level of 4.9. As the fermentation process progressed, methanogenic archaea could timely convert VFA in the system into methane. The pH values ​​of W0-1 (the ratio of original cow dung to domesticated cow dung under wet fermentation was 0:1), W1-1 (the ratio of original cow dung to domesticated cow dung under wet fermentation was 1:1) and W1-0 groups (the ratio of original cow dung to domesticated cow dung under wet fermentation was 1:0) began to increase after 2 days, and the pH recovery effect of the first two groups was more obvious than that of the third group. From the 10th to the 30th day, the overall increase of pH in the three groups was not obvious. The results show that the pH value of the wet anaerobic fermentation system with the addition of the acclimated inoculum (W1-1) in a 1:1 mixture recovers faster than that of the control group (W1-0) without the addition of the acclimated inoculum, which can shorten the recovery time of acid inhibition and maintain the pH at around 7.3, which is suitable for the growth and reproduction of methanogens.

[0025] Figure 2 and Figure 3 The figure shows the changes of daily methane production (measured in VS) and cumulative methane production (measured in VS) with fermentation time in wet anaerobic fermentation under acid inhibition. Figure 2 It can be seen that the gas production peaks of the three groups appeared within 5 to 10 days, the gas production peak of group W1 to 1 appeared the earliest and had the highest peak, followed by group W0 to 1, and group W1 to 0 appeared the latest. After 16 days, the daily methane production of the three groups was not obvious. Figure 3 The cumulative methane production of the three groups showed a trend of first increasing and then stabilizing. The cumulative methane production of group W1-1 was the highest, followed by group W0-1. The methane production of group W1-0 was similar in the first 6 days and began to increase after the 6th day. The results show that in wet anaerobic fermentation, the methane production of the wet anaerobic fermentation system with 1:1 mixed addition of domesticated inoculum (W1-1) is higher than that of the control group (W1-0) without adding domesticated inoculum, which is more conducive to gas production in the anaerobic fermentation process.

[0026] Example 2: This example provides the effect of inoculum acclimation on the changes of various indicators under acid inhibition during dry anaerobic fermentation of corn straw.

[0027] 1. Raw material collection and processing Corn stalks and cow dung were collected as experimental raw materials (in a certain area of ​​Shaanxi Province). The corn stalks were naturally air-dried until their moisture content was less than 10%. They were then crushed and passed through a 20-mesh sieve and stored in a sealed and dry condition at room temperature for later use.

[0028] The inoculum used is cow dung, and the inoculum preparation method is as follows: first, the retrieved cow dung is cultured under constant temperature anaerobically at medium temperature (30-35°C) or high temperature (50-55°C) for about 30 days until the gas production returns to a stable level, which means the taming is complete; then, it is evenly mixed with untamed original cow dung in a mass ratio of 0:1, 1:1 or 1:0 to obtain three types of cow dung inocula.

[0029] 2. Anaerobic fermentation experiment The experiment set up 3 experimental groups: the three kinds of cow dung inocula were added into the mixed fermentation system respectively, and the fermentation system substrate was the corn stalks mentioned above. Each experimental group was set up with 3 replicates.

[0030] Corn stalks and cow dung were mixed evenly, the inoculation amount of cow dung (based on the inoculation ratio) was 30%, and the fermentation TS was 20% (dry). Water was added to the effective volume and mixed evenly, and N was introduced into the anaerobic fermentation reactor. 2 (at least 1 min) to replace the gas in the upper space of the fermentation reactor to achieve an anaerobic reaction environment.

[0031] A 150 mL feeding bottle was used as the anaerobic fermentation reactor, with an effective reaction volume of 100 mL and a fermentation temperature of 35°C. Three inoculation ratios of cow dung were added to the anaerobic fermentation system and mixed thoroughly for dry anaerobic fermentation. The fermentation reactor was fully stirred once every 24 h, and pH was measured, fermentation gas was collected, and gas production volume was measured every 48 h. The cumulative gas production of each experimental group was counted until gas production stopped.

[0032] Experimental results: Figure 4The effect of three inoculants on the pH of corn straw dry fermentation system under acid inhibition. Similar to wet anaerobic fermentation, hydrolytic bacteria including cellulose decomposing bacteria and starch decomposing bacteria decompose organic matter to produce a large amount of acid from 0 to 2 days, resulting in a rapid decrease in the pH of the fermentation system. From 2 to 34 days, the pH values ​​of group D1-1 (the ratio of original cow dung to domesticated cow dung under dry fermentation was 1:1) and group D1-0 (the ratio of original cow dung to domesticated cow dung under dry fermentation was 1:0) rose steadily, and the pH recovery time of group D0-1 was longer than that of the first two groups, and the pH did not change steadily until 38 days. Overall, although the pH trends of group D1-1 and group D1-0 were roughly the same during the recovery period of the fermentation system, the pH recovery rate of group D1-1 was faster, which had a significant effect on the improvement of gas production in the system.

[0033] Figure 5 and Figure 6 The figure shows the daily methane production (in VS) and cumulative methane production (in VS) over time in dry anaerobic fermentation under acid inhibition. Figure 2 Compared with wet fermentation, Figure 5 The start-up time of methane production was longer. The gas production peaks of D0-1 (the ratio of original cow dung to domesticated cow dung under dry fermentation was 0:1), D1-1 and D1-0 groups all appeared on the 40th day. Although the gas production peak of D1-0 group was the highest, the peak duration was short. Overall, the gas production effect was not as good as that of D0-1 and D1-1 groups. Figure 6 The cumulative methane production showed a trend of first rising rapidly and then remaining unchanged, then rising and then stabilizing. The cumulative methane production in the D0-1 group was the highest in the first 30 days, and the methane production in the D1-1 group was the highest in 30-70 days, followed by the D0-1 group, and the D1-0 group was the lowest. The results show that in the dry anaerobic fermentation system with a 1:1 mixture of domesticated inoculum (D1-1), the daily methane production and cumulative methane production were higher than those in the untreated original inoculum group (D1-0), which is more conducive to gas production in the anaerobic fermentation system.

[0034] Example 3: This example provides the effect of inoculum acclimation on the changes of various indicators under ammonia nitrogen inhibition during wet anaerobic fermentation of corn straw.

[0035] 1. Raw material collection and processing Corn stalks and cow dung were collected as experimental raw materials (in a certain area of ​​Shaanxi Province). The corn stalks were naturally air-dried until their moisture content was less than 10%. They were then crushed and passed through a 20-mesh sieve and stored in a sealed and dry condition at room temperature for later use.

[0036] The inoculum used is cow dung, and the inoculum preparation method is as follows: first, the retrieved cow dung is cultured under constant temperature anaerobically at medium temperature (30-35°C) or high temperature (50-55°C) for about 30 days until the gas production returns to a stable level, which means the taming is complete; then, it is evenly mixed with untamed original cow dung in a mass ratio of 0:1, 1:1 or 1:0 to obtain three types of cow dung inocula.

[0037] 2. Anaerobic fermentation experiment The experiment set up 3 experimental groups: the three kinds of cow dung inocula were added into the mixed fermentation system respectively, and the fermentation system substrate was the corn stalks mentioned above. Each experimental group was set up with 3 replicates.

[0038] Corn stalks and cow dung were mixed evenly, the inoculation amount of cow dung (based on the inoculation ratio) was 30%, and the fermentation TS was 8% (wet). Water was added to the effective volume and mixed evenly, and N was introduced into the anaerobic fermentation reactor. 2 (at least 1 min) to replace the gas in the upper space of the fermentation reactor to achieve an anaerobic reaction environment.

[0039] A 150 mL feeding bottle was used as the anaerobic fermentation reactor, with an effective reaction volume of 100 mL and a fermentation temperature of 35°C. Three inoculation ratios of cow dung were added to the anaerobic fermentation system and mixed thoroughly for wet anaerobic fermentation. The fermentation reactor was fully stirred once every 24 h, and pH was measured, fermentation gas was collected, and gas production volume was measured every 48 h. The cumulative gas production of each test group was counted until the gas production stopped.

[0040] Experimental results: Figure 7 The effects of three inoculants on the pH in the wet fermentation system of corn straw under ammonia nitrogen inhibition. As the anaerobic fermentation reaction proceeded, the pH values ​​of each treatment group showed a trend of decreasing first and then increasing. On the 6th day of fermentation, the hydrolytic acidifying bacteria in the reaction system W0-1, W1-1 and W1-0 groups quickly converted macromolecular organic matter into intermediates such as volatile fatty acids, and the pH value decreased. Subsequently, the pH value of the W1-1 group began to gradually increase, while the pH values ​​of the W0-1 and W1-0 groups continued to decrease, reaching the lowest values ​​of 8.17 and 7.62, respectively, on the 16th day of the reaction. The results show that the addition of the original inoculant and the acclimated inoculant (W1-1) mixed in a ratio of 1:1 to the wet anaerobic fermentation system can quickly restore the pH in the system to a state suitable for the growth of methanogens.

[0041] Figure 8 and Fig. 9 The figure shows the changes of daily methane production (measured in VS) and cumulative methane production (measured in VS) with fermentation time in wet anaerobic fermentation under ammonia nitrogen inhibition. Figure 8It can be seen that the overall trend of daily methane production in groups W0-1, W1-1 and W1-0 is roughly the same, all of which increase first and then decrease. However, the time and peak value of reaching the peak are not the same. The peak of daily methane production in groups W1-1 and W0-1 both appeared on the 10th day of fermentation; while the peak of daily methane production in group W1-0 appeared later, on the 14th day of fermentation, and the peak value was the lowest. Fig. 9 The cumulative gas production of the three groups experienced a trend of rapid increase and then flattening, with the highest cumulative gas production in group W1-1, followed by group W0-1, and the lowest in group W1-0. The results show that in wet anaerobic fermentation, the methane production of the 1:1 mixed addition of domesticated inoculum (W1-1) is higher than that of the control group (W1-0) without adding domesticated inoculum, which is more conducive to gas production in the anaerobic fermentation system.

[0042] Example 4: This example provides the effect of inoculum acclimation on the changes of various indicators under ammonia nitrogen inhibition during dry anaerobic fermentation of corn straw.

[0043] 1. Raw material collection and processing Corn stalks and cow dung were collected as experimental raw materials (in a certain area of ​​Shaanxi Province). The corn stalks were naturally air-dried until their moisture content was less than 10%. They were then crushed and passed through a 20-mesh sieve and stored in a sealed and dry condition at room temperature for later use.

[0044] The inoculum used is cow dung, and the inoculum preparation method is as follows: first, the retrieved cow dung is cultured under constant temperature anaerobically at medium temperature (30-35°C) or high temperature (50-55°C) for about 30 days until the gas production returns to a stable level, which means the taming is complete; then, it is evenly mixed with untamed original cow dung in a mass ratio of 0:1, 1:1 or 1:0 to obtain three types of cow dung inocula.

[0045] 2. Anaerobic fermentation experiment The experiment set up 3 experimental groups: the three kinds of cow dung inocula were added into the mixed fermentation system respectively, and the fermentation system substrate was the corn stalks mentioned above. Each experimental group was set up with 3 replicates.

[0046] Corn stalks and cow dung were mixed evenly, the inoculation amount of cow dung (based on the inoculation ratio) was 30%, and the fermentation TS was 20% (dry). Water was added to the effective volume and mixed evenly, and N was introduced into the anaerobic fermentation reactor. 2 (at least 1 min) to replace the gas in the upper space of the fermentation reactor to achieve an anaerobic reaction environment.

[0047] A 150 mL feeding bottle was used as the anaerobic fermentation reactor, with an effective reaction volume of 100 mL and a fermentation temperature of 35°C. Three inoculation ratios of cow dung were added to the anaerobic fermentation system and mixed thoroughly for dry anaerobic fermentation. The fermentation reactor was fully stirred once every 24 h, and pH was measured, fermentation gas was collected, and gas production volume was measured every 48 h. The cumulative gas production of each experimental group was counted until gas production stopped.

[0048] Experimental results: Fig.10 The effects of three inoculants on the pH of corn straw dry fermentation system under ammonia nitrogen inhibition. As the anaerobic fermentation reaction proceeded, the pH of groups D0-1, D1-1 and D1-0 showed a trend of first rising, then falling, and finally fluctuating. On the 12th day of fermentation, the pH of groups D0-1, D1-1 and D1-0 rose to the highest, which were 7.03, 6.95 and 6.73, respectively. From the 45th day of fermentation to the end of gas production, the system pH of group D1-1 was stable at about 6.5, while the pH of the control group D1-0 fluctuated between 6.3 and 6.6. The results show that the pH of the dry anaerobic fermentation system with 1:1 mixed addition of domesticated inoculants recovered faster than the control group (D1-0) without adding domesticated inoculants, which is more conducive to the recovery of gas production in the anaerobic fermentation system.

[0049] Fig.11 and Fig.12 This is a graph showing the changes in daily methane production (measured in VS) and cumulative methane production (measured in VS) over fermentation time during dry anaerobic fermentation under ammonia nitrogen inhibition. Fig.11 and Fig.12 The results showed the same trend of change. The overall trend of daily methane production and cumulative methane production in groups D0-1, D1-1 and D1-0 was up and down. The fluctuations of groups D1-1 and D0-1 were greater than those of groups D1-0, ranging from 9.0 to 47.5 and 11.5 to 42.5, respectively. In the early stage of fermentation, the cumulative gas production of group D1-1 was higher. The results show that in the early stage of dry anaerobic fermentation, adding the domesticated inoculum (D1-1) in a 1:1 mixture can effectively increase the gas production of the anaerobic fermentation system.

[0050] The above-described embodiments are part of the embodiments of the present invention, but not all of them. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but rather represents selected embodiments of the present invention. All other embodiments obtained without creative work and related deductions and substitutions made by ordinary technicians in the field under the conditions of the concept of the present invention belong to the scope of protection of the present invention.

Claims

1. A method for acclimating inoculum for relieving acid or ammonia nitrogen inhibition in an anaerobic fermentation system, characterized in that: include: Using biomass degradable raw materials as anaerobic fermentation substrates, the domesticated inoculum with good tolerance and the original untreated inoculum are mixed in a certain ratio and put into the anaerobic fermentation system for wet anaerobic fermentation or dry anaerobic fermentation. The preparation of the domesticated inoculum with good tolerance includes: culturing poultry and livestock manure, activated sludge, industrial anaerobic digestion residues, mineralized garbage or biogas fermentation liquid at a medium temperature of 30-35°C or a high temperature of 50-55°C in a constant temperature anaerobic fermentation system until the gas production is stable, so as to obtain the domesticated inoculum with good tolerance.

2. The inoculum acclimation method for relieving acid or ammonia nitrogen inhibition in an anaerobic fermentation system according to claim 1, characterized in that: The mixing ratio of the domesticated inoculum with good tolerance to the original untreated inoculum is 1:

1.

3. The inoculum acclimation method for relieving acid or ammonia nitrogen inhibition in an anaerobic fermentation system according to claim 1, characterized in that: The original untreated inoculum is livestock excrement, activated sludge, industrial anaerobic digestion residue, mineralized garbage or biogas fermentation liquid.

4. The inoculum acclimation method for relieving acid or ammonia nitrogen inhibition in an anaerobic fermentation system according to claim 1, characterized in that: The anaerobic fermentation substrate includes crop straw waste and forestry waste.

5. The method for acclimating an inoculum for relieving acid or ammonia nitrogen inhibition in an anaerobic fermentation system according to claim 1, characterized in that: The wet anaerobic fermentation dry matter content TS=5-10%, or the dry anaerobic fermentation dry matter content TS=20-30%.

Images