JP2000239085A - Suppression of ammonia occurrence during composting process - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively suppress the occurrence of ammonia and amines during a composting process, by adding a polymeric substance that forms organic acids to the compost or the composting substance by the decomposition during the composting process. SOLUTION: A high-molecular weight substance that can generate organic acids during the composting process is added to the compost and the raw composting substance (urea sludge, kitchen garbage, food product and the like). The polymer substance to be added is a biodegradable resin, preferably fatty acid ester, fatty acid polyamide, fatty acid polyester amide, poly(vinyl alcohol). The weight ratio of the compost to the polymer substance is 10/90-90/10, when necessary, spawns are added to the composting mixture in an amount of <=40 pts.wt. per 100 pts.wt. of the starting substance and, in a preferred embodiment, 100-500 pts.wt. per 100 pts.wt. of the starting substance of aeration improver, for example, saw dust is added to the composting mixture.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for suppressing the generation of ammonia in a composting process, and more particularly, to a compost or a compost raw material, which is added with a polymer substance which generates an organic acid by decomposition in the composting process. The present invention relates to a method for suppressing the generation of ammonia in a composting process.

[0002]

2. Description of the Related Art Conventionally, human waste and the like have been decomposed by microorganisms, but odors such as ammonia and amines are generated during the treatment, which is a problem in the treatment plant. For this reason, the addition of an adsorbent, an absorbent and the like is being studied. However,
When they are added, there is a problem that microorganisms contributing to the decomposition are affected or the cost is increased.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to suppress the generation of odors due to ammonia or amines during the composting process, particularly the generation of ammonia, at a low cost without adversely affecting microorganisms contributing to decomposition. Is to provide a way.

[0004]

Means for Solving the Problems The present inventors evaluated the degradability of a biodegradable resin such as polycaprolactone (PCL) in the composting process,
When a biodegradable resin such as CL was added, the amount of ammonia generated during the composting process was smaller than in the experiment in which no biodegradable resin was added. I found it empirically. One of the reasons for this is probably that during the decomposition process, fatty acids having a certain structure, which are intermediates for decomposing PCL, are generated, and neutralize the ammonia generated during the composting process. If biodegradable resins such as PCL, polylactic acid, and aliphatic polyesters from aliphatic carboxylic acids and aliphatic diols have the property of "neutralize ammonia", these biodegradable resins can be used. It is not only a plastic that is easily degraded by microorganisms, but also has the property of reducing ammonia.It is one of the means to solve the problem of odor that has hindered the spread of composting. It was thought that it could be. Accordingly, as a result of intensive studies on the reduction of ammonia in the composting process by positively utilizing the property of "neutralizing ammonia", it was found that such a problem could be solved, and the present invention was completed. Was.

That is, a first aspect of the present invention provides a method for suppressing the generation of ammonia in the composting process, which comprises adding, to compost or a compost raw material, a polymer substance that generates an organic acid by decomposition in the composting process. .
A second aspect of the present invention is that the composting material is human waste sludge, sludge, garbage, food, feed, fertilizer, or a mixture thereof, and the ammonia generation is suppressed during the composting process according to the first aspect of the present invention. Provide a way. Third of the present invention
The present invention provides the method for suppressing ammonia generation in the composting process according to the first aspect of the present invention, wherein the polymer substance that generates an organic acid by decomposition in the composting process is a biodegradable resin. A fourth aspect of the present invention is the composting process according to the third aspect, wherein the biodegradable resin is an aliphatic polyester, an aliphatic polyamide, an aliphatic polyesteramide, polyvinyl alcohol or a mixture thereof. A method for suppressing ammonia generation is provided. A fifth aspect of the present invention is that the aliphatic polyester comprises (i) a hydroxycarboxylic acid, (ii) a lactone, (iii) an aliphatic dicarboxylic acid and an aliphatic diol, and a mixture of (i) to (iii). The method for suppressing ammonia generation in the composting process according to the fourth aspect of the present invention, wherein the aliphatic polyester is obtained by homopolymerizing or copolymerizing one or more monomers for aliphatic polyester selected from the group. I will provide a. A sixth aspect of the present invention is characterized in that (i) the hydroxycarboxylic acid is lactic acid, glycolic acid, lactide, glycolide, or a mixture thereof.
The present invention provides a method for suppressing the generation of ammonia in the composting process described in (1). The seventh aspect of the present invention is that (ii) the lactone is ε-
Caprolactone, 4-methylcaprolactone, 3,5
The fifth aspect of the present invention, which is 5-trimethylcaprolactone, 3,3,5-trimethylcaprolactone, β-propiolactone, γ-butyrolactone, δ-valerolactone, enantholactone, or a mixture thereof.
The present invention provides a method for suppressing the generation of ammonia in the composting process described in (1). An eighth aspect of the present invention is that (iii) the aliphatic dicarboxylic acid is succinic acid, oxalic acid, adipic acid, or a mixture thereof, and the aliphatic diol is ethylene glycol, 1,4.
-A method for suppressing ammonia generation during composting according to the fifth aspect of the present invention, which is butanediol, neopentyl glycol, or a mixture thereof. A ninth aspect of the present invention is characterized in that the weight ratio of (compost or compost raw material) to (the polymer substance which generates an organic acid by decomposition in the composting process) is 10:90 to 90:10. A method for suppressing the generation of ammonia in the composting process according to the first aspect. According to a tenth aspect of the present invention, there is provided the method for suppressing ammonia generation in the composting process according to the first aspect of the present invention, further comprising adding a microorganism material. An eleventh aspect of the present invention is the first aspect of the present invention, wherein a breathability improving material is further added.
And a method for suppressing the generation of ammonia in the composting process described in A twelfth aspect of the present invention is the method according to the first aspect, wherein the polymer substance that generates an organic acid by decomposition in the composting process is waste of a resin processed product made of a biodegradable resin. A method for suppressing the generation of ammonia in a composting process is provided. A thirteenth aspect of the present invention is the twelfth aspect of the present invention, wherein the processed resin product is an agricultural multi-film, a garbage bag, a drainage net, a foam, a container, a pile, a net, or a mixture thereof. A method for suppressing the generation of ammonia in a composting process is provided.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The compost and compost raw materials used in the present invention include human waste, sludge, garbage, food, feed, animal fertilizer, plant fertilizer, and the like, and mixtures thereof. As human waste, urine of humans, animals, etc.,
Feces and mixtures thereof. Examples of the sludge include human waste treatment sludge, household wastewater sludge, activated sludge for wastewater treatment in various factories, and the like. Raw garbage includes fish and shellfish, livestock meat, eggs, cereals, vegetables and fruits, plants and plants, water and seaweeds, and various other items that are discarded from households, canteens, food manufacturing and processing industries, etc. Examples include animals, plants, microbial garbage, and mixtures thereof, such as processing and fermentation residues. Since they contain nitrogen, they generate ammonia or amines whose structure is unknown but cause odor during the composting process.

[0007] In the present invention, the polymer substance which generates an organic acid by decomposition in the composting process is a biodegradable resin. Organic acids generated by decomposition in the composting process include carboxylic acids and hydroxy acids. The carboxylic acid may be a monocarboxylic acid, a polycarboxylic acid, a hydroxycarboxylic acid, or an acidic amino acid. The generation of the organic acid by the decomposition of the polymer during the composting process is performed gradually, that is, the supply of the organic acid is performed gradually from the polymer. The biodegradable resin, for example, aliphatic polyester, aliphatic polyamide, aliphatic polyester amide,
Polyvinyl alcohol or mixtures thereof.
As the polyvinyl alcohol, those having various molecular weights, saponification degrees and stereoregularities can be used. The aliphatic polyester is selected from the group consisting of (i) hydroxycarboxylic acids, (ii) lactones, (iii) aliphatic dicarboxylic acids and aliphatic diols, and a mixture of (i) to (iii). An aliphatic polyester obtained by homopolymerizing or copolymerizing the above-mentioned monomer for aliphatic polyester.

The above (i) hydroxycarboxylic acids include lactic acid, glycolic acid, lactide, glycolide, and mixtures thereof. (Ii) The lactones include ε-caprolactone, 4-methylcaprolactone, 3,5,5-trimethylcaprolactone, 3,3
Examples include 5-trimethylcaprolactone, β-propiolactone, γ-butyrolactone, δ-valerolactone, enantholactone, or a mixture thereof. In the above (iii), examples of the aliphatic dicarboxylic acid include succinic acid, oxalic acid, adipic acid and a mixture thereof, and examples of the aliphatic diol include ethylene glycol,
4-butanediol, neopentyl glycol, or a mixture thereof. These biodegradable resins include polylactic acid, polyglycolic acid, a copolymer of these original monomers, or a mixture thereof; polycaprolactone, poly β-propiolactone, polyγ-butyrolactone, polyδ-valero. Lactones, copolymers of these original monomers, or mixtures thereof; poly (succinic acid-ethylene glycol), poly (succinic acid-1,4-butanediol), poly (oxalic acid-1,4-butanediol) ,
Poly (oxalic acid-ethylene glycol), poly (oxalic acid-neopentyl glycol), poly (adipic acid-ethylene glycol), poly (adipic acid-1,4-butanediol); or a small amount of urethane bond of these biodegradable resins. And the like. In addition, polylactic acid, etc.
L-form, D-form and D of optical isomers
Since there is a / L- form, a polymer corresponding to each exists, but any of them can be used. As the polyamide, both those obtained by ring-opening polymerization and those obtained by polycondensation can be used. Polyamides obtained by ring-opening polymerization include 2-pyrrolidone, ε-caprolactam, ω-
Examples of ring-opening polymers such as laurolactam and polyamides by polycondensation include polycondensates of hexamethylenediamine and adipic acid, and hexamethylenediamine and sebacic acid and 11-aminoundecanoic acid. Also, these copolymers and mixtures can be used. Examples of the polyesteramide include a ring-opening polymer of a cyclic ester amide, a ring-opening copolymer of a cyclic ester and a cyclic amide, a condensation polymer, and a polymer obtained by transesterification between an aliphatic polyester and a polyamide. Can be used. Examples of ring-opening polymers of cyclic ester amides include morpholine-2,5-dione derivatives and L-lactide, morpholine-2,5-dione derivatives and ε
-Copolymers with caprolactone or mixtures thereof;
There are copolymers containing both glycine and glycolic acid units alternately, L-lactic acid, copolymers containing both L-aspartic acid and glycolic acid units alternately, and mixtures thereof. Examples of the ring-opening copolymer of a cyclic ester and a cyclic amide include ε-caprolactam, ω-laurolactam, a copolymer of a cyclic ester of 2-pyrrolidone and ε-caprolactone, a cyclic amide of δ-valerolactone, or a copolymer thereof. There is a mixture of Examples of the condensation polymer include a dehydrated condensate of a dimer obtained by the reaction of ε-hydroxycaproic acid and methyl ε-aminocaproate, and a terminal acid chloride obtained by reacting a dicarboxylic acid chloride with α, ω-diol. And a condensate obtained by sequentially reacting a terminal hydroxyl group L-lactide oligomer with sebacoyl chloride, 1,6-hexanediamine, or a mixture thereof. Examples of the polymer obtained by transesterification between an aliphatic polyester and a polyamide are polyε-caprolactone and nylon 6,1.
Examples thereof include transesterification products with various nylons such as 1, 12, 46, 66, and 612, and mixtures thereof. Further, as the polylactone used in the present invention,
Various copolymers having a lactone as a main structural unit, for example, a copolymer of lactic acid or glycolic acid, a copolymer of an aliphatic dicarboxylic acid and an aliphatic diol may be used,
In these copolymers, the lactone content is preferably 50% or more.

The biodegradable resin may be a powder, a pellet, a resin processed product (molded product), a resin processed product discarded after use, or a crushed product thereof. Examples of the resin processed product include agricultural multi-films, trash bags, drainage nets, foams, containers, piles, nets, and mixtures thereof.

The mixing weight ratio of compost or a compost raw material and a polymer substance that generates an organic acid by decomposition in the composting process is (compost or compost raw material):
(A polymer substance that generates an organic acid by decomposition in the composting process) is 10:90 to 90:10, preferably 3:90.
0: 70-70: 30, particularly preferably 50: 70-7
0:50. When the mixing ratio of the polymer substance that generates an organic acid by decomposition in the composting process is smaller than the above range, the effect of suppressing the generation of ammonia is weakened. When the mixing ratio is larger than the above range, it is not economical, but does not hinder the composting.

It is preferable to add a seed bacterium as a microbial material to a mixture of compost or a compost raw material and a polymer substance that generates an organic acid by decomposition in the composting process in order to promote the decomposition. The mixture weight ratio of compost or compost raw material and microbial material is 40 parts by weight or less of inoculum per 100 parts by weight of compost or compost raw material,
It is preferably at most 30 parts by weight, more preferably at least 20 parts by weight. There is no particular problem if the mixing ratio of the microbial material is larger than the above range, but it is not economical.

It is preferable to add sawdust and the like as a gas permeability improving material to the compost or a mixture of the compost raw material and a polymer substance which generates an organic acid by decomposition in the composting process. The mixing weight ratio of the compost or the compost raw material and the air permeability improving material is such that the air permeability improving material is 100 to 500 parts per 100 parts by weight of the compost or compost raw material.
Parts by weight, preferably 200 to 400 parts by weight, particularly preferably 250 to 300 parts by weight. If the mixing ratio of the air permeability improving material is larger than the above range, there is no problem in decomposition, but it is not economical.

[0013]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples. [Example 1 and Comparative Example 1] Experimental method As human waste sludge, one generated at a human waste treatment plant in H city (water content 83%) was used. As a mixture for composting, a mixture of sawdust as an air permeability improving material, inoculum as a commercially available microbial material, and PCL in a dry weight ratio of 5: 14: 1: 7, respectively, was used for night soil sludge ( Example 1). For comparison, a mixture having a dry weight ratio of human waste sludge, sawdust and inoculum of 5: 14: 1 was used as a mixture for composting in an experiment in which PCL was not added (Comparative Example 1). FIG. 1 schematically shows the experimental apparatus. The above mixture of Example 1 (or Comparative Example 1) was placed on the stainless steel net 5 in the mini reactor 6 made of Pyrex glass, placed in the incubator 8, and air was supplied through the flow meter 1 to perform composting treatment. Do
The exhaust gas from the mini-reactor 6 is collected in a Tedlar bag (trade name) 7 which is a fluororesin gas collecting bag,
The concentrations of carbon dioxide and ammonia in the collected exhaust gas are quantified using a Kitagawa gas detector (not shown). Further, the volume of the collected exhaust gas is measured using an integrating flow meter (not shown). The initial pH and water content of the compost raw material were adjusted to around 7.2 and 60%, respectively, and 12 g of the composting mixture was added to a mini reactor 6 having a capacity of 80 ml.
And placed in the incubator 8, heated from a room temperature to a set temperature of 60 ° C. at a predetermined heating rate, and then composted at a constant temperature of 60 ° C. for 6 days.
Calculate the amount of carbon dioxide gas generated every 12 hours together with the quantitative value of the carbon dioxide gas concentration, and calculate the carbon change rate corresponding to the degree of decomposition of organic matter from the ratio of the total carbon content contained in night soil sludge. Was. For ammonia, the nitrogen change rate was determined in the same manner. In addition, the measurement of the decomposition rate of PCL is as follows.
It was quantified by subtracting the total amount of generated carbon dioxide in the presence or absence of PCL.

Comparative Example 2 For comparison, the mixture in the experiment without the addition of night soil sludge was the same as in Example 1 except that the dry weight ratios of sawdust, inoculum and PCL were 14: 1: 7, respectively. The test was performed. As a result, the decomposition rate of PCL was almost 0% even after the end of the test as compared with FIG.

Experimental Results and Discussion FIG. 2 shows the change over time in the carbon change rate. The horizontal axis in FIG. 2 indicates time (h), and the vertical axis indicates the rate of change of carbon (%). Comparative Example 1
(A-1 and A-2, indicated by circles in the figure) and Example 1
(B-1 and B-2, indicated by squares in the figure), the experiments were performed twice each, and they all agreed well, confirming that the composting in this experiment had reproducibility. Was.
In Comparative Example 1, the organic matter in the human waste sludge was decomposed in the early stage of composting, but no significant change was observed thereafter.
At 144 hours, the final rate of carbon change was around 37%. On the other hand, even in Example 1 in which PCL was added, the organic matter in the night soil sludge was decomposed in the early stage of composting. However, since the active decomposition continued thereafter, PCL was not decomposed even in the composting using night soil sludge. It was confirmed that it was actively decomposed. Note that the final value of the carbon change rate in Example 1 was around 150%, indicating that the PCL was actively decomposed from the fact that the carbon change rate exceeded 100%. FIG. 3 shows the change over time in the decomposition rate of only PCL in Example 1. The horizontal axis in FIG. 3 represents time (h), and the vertical axis represents the decomposition rate (%) of PCL. The slope of the PCL decomposition rate curve when night soil sludge was used increased linearly from the initial stage of composting, and finally reached a value of about 63% in 144 hours. When night soil sludge was used, the decomposition of PCL started early, and the PCL decomposition rate reached around 63% after 144 hours. However, it is considered that there was little organic matter easily decomposed in night soil sludge. . Therefore, depending on the type of compost material, PC
L can be decomposed from the beginning of composting. It was suggested that it could be decomposed in a shorter period of time.

FIG. 4 shows the change over time in the nitrogen change rate. The horizontal axis in FIG. 4 indicates time (h), and the vertical axis indicates the rate of change of nitrogen (%). Regarding the nitrogen change rate, similarly to the case of the carbon change rate, Comparative Example 1 (A-1 and A-2, indicated by circles in the figure) and Example 1 (B-1 and B-2, square marks in the figure) ), It was confirmed that the composting performed twice each had reproducibility. In Comparative Example 1, ammonia was actively generated from the initial stage of composting, and finally reached a value of about 6% in nitrogen change rate. On the other hand, PCL
In Example 1 in which was added 24, 36 in the initial stage of composting.
At time, it was slightly larger than Comparative Example 1, but 4
After the eighth hour, the nitrogen change rate curve became constant. In addition,
The final nitrogen change rate in Example 1 was around 3%. It is not clear why Example 1 produced more ammonia than Comparative Example 1 in the early stage of composting, but it is also considered that the addition of PCL promoted the decomposition of night soil sludge itself and generated more ammonia. Was done.

FIG. 5 shows the change over time of the ammonia generation rate. The horizontal axis in FIG. 5 indicates time (h), and the vertical axis indicates the generation rate of ammonia (× 10 ⁶ mol / hour). Comparative Example 1
(A-1 and A-2, indicated by circles in the figure) and Example 1
(B-1 and B-2, indicated by squares in the figure), the ammonia generation rate was maximum at 36 hours, and then gradually decreased. In the initial stage of composting, the rate of ammonia generation in Example 1 was temporarily higher than that in Comparative Example 1, but thereafter, Comparative Example 1 was lower than Example 1. It should be particularly noted that in Comparative Example 1 where PCL was not added, ammonia was generated until the end of composting, whereas in Example 1, the generation of ammonia was hardly detected after 60 hours. It is. From this, consider the conditions that cause PCL to be decomposed as early as possible.
It was thought that complete removal of ammonia was possible by using the decomposition intermediate of.

[0018]

According to the present invention, it is possible to suppress the generation of odors due to ammonia or amines in the composting process at a low cost without adversely affecting microorganisms contributing to the decomposition in the treatment of decomposing night soil. did it. Further, according to the present invention, agricultural multi-films and the like discarded after use as a polymer substance that generates organic acids by decomposition in the composting process are collected, and composted together with livestock excrement and garbage. In this case, the effects of waste treatment and deodorization can be achieved at the same time.

[Brief description of the drawings]

FIG. 1 is a diagram showing an experimental device used in the present invention.

FIG. 2 is a diagram showing the change over time in the rate of change of carbon in Example 1 and Comparative Example 1.

FIG. 3 is a graph showing a change over time in a carbon change rate of Comparative Example 2.

FIG. 4 is a diagram showing the change over time in the rate of change of nitrogen in Example 1 and Comparative Example 1.

FIG. 5 is a graph showing a change over time in an ammonia generation rate in Example 1 and Comparative Example 1.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flow meter 2 Bubbler 3 Carbon dioxide trap 4 Silicon rubber stopper 5 Stainless steel net 6 Mini reactor 7 Tedlar bag 8 Incubator

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 67/04 C08L 77/12 77/00 B09B 3/00 D 77/12 ZABA // C08L 101/16 C08L 101/00 A F term (reference) 4D004 AA02 AA03 AA07 BA04 CA19 CA48 CB06 CC08 CC17 4H061 AA02 CC35 CC47 CC51 CC55 DD20 EE35 EE36 EE37 EE61 EE66 HH42 4J002 AA00W AA07W BE02X CF03X CF18X CF19X CL00X

Claims (13)

[Claims] 1. A method for suppressing ammonia generation in a composting process, comprising adding a polymer substance that generates an organic acid by decomposition in the composting process to compost or compost raw material. 2. The method according to claim 1, wherein the compost raw material is human waste sludge, sludge, garbage, food, feed, fertilizer, or a mixture thereof. 3. The method according to claim 1, wherein the polymer substance that generates an organic acid by decomposition in the composting process is a biodegradable resin. 4. The method according to claim 3, wherein the biodegradable resin is an aliphatic polyester, an aliphatic polyamide, an aliphatic polyesteramide, a polyvinyl alcohol or a mixture thereof. . 5. An aliphatic polyester comprising (i) a hydroxycarboxylic acid, (ii) a lactone, (iii) an aliphatic dicarboxylic acid and an aliphatic diol, and (i) to (ii)
5. An aliphatic polyester obtained by homopolymerizing or copolymerizing one or more monomers for aliphatic polyester selected from the group consisting of the mixture of i).
3. The method for suppressing the generation of ammonia in the composting process according to item 1. 6. The method according to claim 5, wherein (i) the hydroxycarboxylic acid is lactic acid, glycolic acid, lactide, glycolide, or a mixture thereof. (Ii) The lactones are ε-caprolactone, 4-methylcaprolactone, 3,5,5-trimethylcaprolactone, 3,3,5-trimethylcaprolactone, β-propiolactone, γ-butyrolactone, δ
The method according to claim 5, wherein the method is valerolactone, enantholactone, or a mixture thereof. (Iii) The aliphatic dicarboxylic acid is succinic acid, oxalic acid, adipic acid, or a mixture thereof, and the aliphatic diol is ethylene glycol, 1,4-butanediol, neopentyl glycol, or a mixture thereof. The method according to claim 5, wherein ammonia is suppressed during the composting process. 9. The method according to claim 1, wherein the weight ratio of (compost or compost raw material) to (polymeric substance which generates an organic acid by decomposition in the composting process) is from 10:90 to 90:10. The method for suppressing the generation of ammonia in the composting process according to the above. 10. The method according to claim 1, further comprising adding a microorganism material. 11. The method according to claim 1, further comprising adding a gas permeability improving material. 12. The composting process according to claim 1, wherein the polymer substance that generates an organic acid by decomposition in the composting process is waste of a resin processed product made of a biodegradable resin. Ammonia generation suppression method. 13. The resin-processed product is an agricultural multi-film,
13. The method according to claim 12, wherein the method is a trash bag, a drain net, a foam, a container, a pile, a net, or a mixture thereof.