阅读说明：本技术 一种强化易降解生物质废物厌氧发酵产酸的方法 (Method for strengthening anaerobic fermentation acid production of easily degradable biomass waste ) 是由 吕凡 聂二旗 何品晶 章骅 邵立明 于 2021-08-12 设计创作，主要内容包括：本发明属于生物质废物和生物质资源化利用技术领域,具体涉及一种强化易降解生物质废物厌氧发酵产酸的方法,所述方法为将易降解生物质废物与接种物置于厌氧环境中进行厌氧发酵产酸。本发明通过精调控制厌氧消化系统中的反应温度及时间,塑造微生物的种类,刺激提高酸化细菌的活性,进而达到促进易降解生物质废物的水解酸化,而抑制甲烷菌的活性,避免产生的脂肪酸向甲烷转化。本发明可以通过温度和反应时间控制实现定向产酸,无需添加外源性抑制剂、节省成本、作用效果持续、发酵条件易于控制、运行成本低、无二次污染。(The invention belongs to the technical field of biomass waste and biomass resource utilization, and particularly relates to a method for strengthening anaerobic fermentation acid production of easily degradable biomass waste. According to the invention, the reaction temperature and time in the anaerobic digestion system are finely adjusted and controlled, the types of microorganisms are shaped, the activity of acidifying bacteria is stimulated and improved, the hydrolytic acidification of easily degradable biomass waste is promoted, the activity of methane bacteria is inhibited, and the conversion of the generated fatty acid to methane is avoided. The invention can realize directional acid production by controlling temperature and reaction time, does not need to add exogenous inhibitors, saves cost, has continuous effect, easy control of fermentation conditions, low operation cost and no secondary pollution.)

1. A method for strengthening anaerobic fermentation acid production of easily degradable biomass waste is characterized in that the acid production efficiency and the reaction temperature and reaction time during directional acid production depend on the effective accumulated temperature accumulated by the anaerobic fermentation of the easily degradable biomass waste; the ratio of the easily degradable biomass waste to the inoculum is 1: 1-1: 5; based on volatile solids/organic content VS:

the calculation formula of the effective accumulated temperature is as follows:

T＝∑(T_i-T₀)×Δt

wherein, T: effective accumulated temperature in units of (DEG C. d);

T_i: a certain constant temperature (T is more than or equal to 26 ℃ and less than or equal to 65 ℃);

T₀: the starting propagation temperature (25 ℃) of the microorganisms in the digestion reaction system;

Δ t: the number of days for which the constant temperature is maintained (6 d. ltoreq. DELTA.t. ltoreq.23 d).

2. The method for enhancing the acid production of the easily degradable biomass waste through the anaerobic fermentation of the easily degradable biomass waste as claimed in claim 1, wherein the reaction temperature and the reaction time are controlled so that the acetic acid yield is highest when the effective accumulated temperature is 209 ℃ d < T <275 ℃ d and the reaction is carried out for 11 days at 47 +/-3 ℃.

3. The method for enhancing acid production through anaerobic fermentation of easily degradable biomass waste as claimed in claim 1, wherein the reaction temperature and the reaction time are controlled so that the yield of propionic acid is the highest when the reaction is carried out at 44 ± 3 ℃ for 23 days when the effective accumulated temperature is 368 ℃ d < T <506 ℃ d.

4. The method for enhancing the acid production of the easily degradable biomass waste through the anaerobic fermentation of the easily degradable biomass waste as claimed in claim 1, wherein the reaction temperature and the reaction time are controlled so that the butyric acid yield is highest when the reaction is carried out for 11 days at 62 +/-3 ℃ when the effective accumulated temperature is 374 ℃ d < T <440 ℃ d.

5. The method for enhancing the acid production of the easily degradable biomass waste through the anaerobic fermentation of the easily degradable biomass waste as claimed in claim 1, wherein the ratio of the easily degradable biomass waste to the inoculum is 1: 3-1: 5.

6. The method for enhancing the acid production of the easily degradable biomass waste through the anaerobic fermentation of the easily degradable biomass waste as claimed in claim 1, wherein the easily degradable biomass waste is crushed to form a uniform raw material.

7. The method for enhancing the acid production of the easily degradable biomass waste through the anaerobic fermentation of the easily degradable biomass waste as claimed in claim 1, wherein the inoculum is sludge or biogas residues of an anaerobic digestion plant.

8. The method for enhancing the acid production of the easily degradable biomass waste through the anaerobic fermentation of the easily degradable biomass waste as claimed in claim 1, wherein the solid content of the mixed liquid formed by the easily degradable biomass waste and the inoculum is kept below 8%.

Technical Field

The invention relates to the technical field of biomass waste and biomass resource utilization, in particular to a method for strengthening anaerobic fermentation acid production of easily degradable biomass waste.

Background

Anaerobic digestion is one of the high-efficiency biological treatment technologies, and has been widely applied in the field of solid waste treatment such as agricultural solid waste, kitchen waste, municipal sludge and the like. The easily degradable biomass waste can be subjected to anaerobic fermentation to form energy substances such as Volatile Fatty Acids (VFAs), methane and the like. Among them, Volatile Fatty Acids (VFAs) are important organic substrates for chemical engineering such as biosynthesized plastics. However, the anaerobic digestion system usually contains two functional floras of acid-producing bacteria and methanogen, and as an intermediate product of anaerobic fermentation, VFAs are easily and rapidly converted into gas-phase methane and carbon dioxide by methanogen, so that the VFAs concentration of the fermentation liquor is low, and the concentration and separation costs are high, thereby limiting the high-value utilization of the VFAs. Therefore, the method has important research significance on how to reduce the metabolic activity of methanogens in the system, block the methanation process of the easily degradable biomass waste, enable anaerobic digestion to stay in an acidogenic stage and realize directional organic acid conversion of the easily degradable biomass waste.

The efficient preparation of VFAs from readily degradable biomass waste as a fermentation substrate has gained increasing attention in the environmental field. In addition, the inventor of the related art has conducted research on enhancing acid production of easily degradable biomass waste in the anaerobic digestion process, but the existing research mostly focuses on carrying out material transportation pretreatment by physical and chemical methods to improve the bioavailability of biomass waste such as sludge (CN102583917B, CN105132475A, CN102586344B and CN103923951A), or adding inhibitors to block methanogenic metabolic pathways (CN100526469C) to control anaerobic digestion to stay in the acid production stage. However, the bio-availability of easily degradable biomass wastes such as kitchen wastes is extremely high, the hydrolysis acidification rate is high, and the methanation is the reason for preventing the concentration of VFAs from increasing. Although exogenous inhibitors such as 2-bromoethanesulfonic acid (BES) and the like can block the methanogenic metabolic pathway in a short time, the inhibitors lose effectiveness in a long time because the inhibitors are degraded and the amount of the inhibitors to be added is large, so that the chemical cost is high, and the fermentation liquor has ecological safety risk. The mode of adopting VFAs as an endogenous inhibitor not only blocks a methanogenesis metabolic pathway, but also severely inhibits hydrolytic acidification microorganisms and enzyme activity of biomass wastes, so that the concentration of the VFAs cannot be further improved.

Because of the differences in temperature sensitivity between acid-producing bacteria and methanogenic bacteria in anaerobic digestion systems (Nie, E.; He, P.; Zhang, H.; Hao, L.; Shao, L.; Hu, F.; How do thermal regulation and anaerobic directed acidification by controlling temperature and fermentation time 2021,150,111453), anaerobic directed acidification is expected and has not been reported in this study.

The invention takes easily degradable biomass waste as a raw material, and produces the medium-chain fatty acid with high added value by controlling the temperature and the fermentation time in the anaerobic digestion process, thereby providing a new idea for the resource utilization of the easily degradable biomass waste. The method has simple production process and good economic, social and environmental benefits.

Disclosure of Invention

Aiming at the defects, the invention provides a method for strengthening anaerobic fermentation acid production of easily degradable biomass wastes by using the easily degradable biomass wastes as raw materials and controlling the anaerobic fermentation temperature and time to produce medium-chain fatty acid, and provides a new idea for realizing resource utilization of the easily degradable biomass wastes.

The invention provides the following technical scheme: a method for strengthening anaerobic fermentation acid production of easily degradable biomass waste, wherein the acid production efficiency and the reaction temperature and reaction time during directional acid production depend on the accumulated effective accumulated temperature of the anaerobic fermentation of the easily degradable biomass waste; the ratio of the easily degradable biomass waste to the inoculum is 1: 1-1: 5; based on volatile solids/organic content VS:

the calculation formula of the effective accumulated temperature is as follows:

T＝∑(T_i-T₀)×Δt

wherein, T: effective accumulated temperature in units of (DEG C. d);

T_i: a certain constant temperature (T is more than or equal to 26 ℃ and less than or equal to 65 ℃);

T₀: the starting propagation temperature (25 ℃) of the microorganisms in the digestion reaction system;

Δ t: the number of days for which the constant temperature is maintained (6 d. ltoreq. DELTA.t. ltoreq.23 d).

Further, the reaction temperature and the reaction time are controlled such that the acetic acid yield is highest at 47 ± 3 ℃ for 11 days when the effective integrated temperature is 209 ℃ · d < T <275 ℃ · d.

Further, the reaction temperature and the reaction time are controlled such that the yield of propionic acid is highest when the reaction is carried out at 44 ± 3 ℃ for 23 days when the effective accumulated temperature is 368 ℃ d < T <506 ℃ d.

Further, the reaction temperature and time are controlled such that the yield of butyric acid is highest at 62 ± 3 ℃ for 11 days when the effective integrated temperature 374 ℃ · d is less than T <440 ℃ · d.

Further, the ratio of the easily degradable biomass waste to the inoculum is 1: 3-1: 5.

Further, the easily degradable biomass waste is crushed to form a uniform raw material.

Further, the inoculum is sludge or biogas residue of an anaerobic digestion plant.

Further, the solid content of the mixed liquid formed by the easily degradable biomass waste and the inoculum is kept below 8%.

The mechanism of the present invention:

the temperature changes the original sludge microorganism inoculation groups by shaping the types of microorganisms in an anaerobic digestion system, stimulates to generate more acidification bacteria and inhibits the activity of methane bacteria, thereby achieving the purposes of promoting the hydrolytic acidification of easily degradable biomass wastes and inhibiting the conversion of the generated fatty acid to methane.

The invention has the beneficial effects that:

1. the method provided by the invention improves the yield of volatile fatty acid in the anaerobic fermentation system.

2. The method provided by the invention can realize directional acid production by controlling the temperature and the reaction time, and has high selectivity.

3. The method provided by the invention does not need to add an exogenous inhibitor, saves cost, has obvious effect, is convenient and simple to regulate and control, and is easy to realize automation.

4. The method provided by the invention has the advantages of easy control of anaerobic fermentation conditions, low operation cost and no secondary pollution.

Drawings

The invention will be described in more detail hereinafter on the basis of embodiments and with reference to the accompanying drawings. Wherein:

FIG. 1 shows the method of the present invention in examples 1-3, the amount and kind of volatile fatty acid produced by the degradable biomass waste under the control of different reaction temperature and reaction time.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

EXAMPLE 1 production of acetic acid

In the method for enhancing anaerobic fermentation acid production of easily degradable biomass waste provided by this embodiment, the easily degradable biomass waste is crushed by a crusher, then is loaded into an anaerobic reaction bottle with a specification of 1000mL, then 100mL of inoculum is added, after mixing, the pH is adjusted to 7.0, the solid content is adjusted to 5%, a plug made of butyl rubber is covered, an aluminum cover is used for sealing, and then N is used₂Blowing off for 10 minutes and keeping an anaerobic environment. Placing the anaerobic reaction bottle in a water bath kettle with a constant temperature of 47 + -3 deg.C, as shown in figure 1, reacting for 11 days, and allowing the effective accumulated temperature to reach 209 deg.C. d<T<The maximum amount of acetic acid was obtained at 275 ℃ d. The fatty acid determination method is to collect liquid samples, centrifuge at 15200rpm for 10 minutes, and then determine the concentration of volatile fatty acids in the liquid phase after centrifugation by gas chromatography. Wherein the gas chromatograph selects the FID detector, and the instrument operating parameters are as follows: the sample introduction temperature is 230 ℃, the column temperature is 65 ℃, and the detector temperature is 300 ℃.

EXAMPLE 2 production of propionic acid

The treatment process of the easily degradable biomass waste, the reaction bottling process, the pretreatment process of the liquid sample and the determination method of the fatty acid in the embodiment are the same as those in the embodiment 1. Aiming at the directional propionic acid production, the reaction temperature is controlled to be 44 +/-3 ℃ in a water bath, as shown in figure 1, the reaction time is 23 days, the effective accumulated temperature reaches 368 ℃ d < T <506 ℃ d, and the maximum amount of propionic acid can be obtained.

EXAMPLE 3 production of butyric acid

The treatment process of the easily degradable biomass waste, the reaction bottling process, the pretreatment process of the liquid sample and the determination method of the fatty acid in the embodiment are the same as those in the embodiment 1. Aiming at the oriented production of butyric acid, the reaction temperature is controlled to be 62 +/-3 ℃ in a water bath, as shown in figure 1, the reaction time is 11 days, the effective accumulated temperature reaches 374 ℃ d < T <440 ℃ d, and the maximum amount of butyric acid can be obtained.

The above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Furthermore, those skilled in the art will appreciate that while some embodiments herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the invention and form different embodiments. For example, in the claims above, any of the claimed embodiments may be used in any combination. The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.