JPS609879B2 - How to dispose of solid waste - Google Patents

Description

[Detailed description of the invention]

The present invention applies to paper, kitchen waste, plastic, glass, and metal.
The present invention relates to a method for treating solid waste containing at least one type of wood chips as a main component, that is, municipal waste, and relates to a method for treating municipal waste that recovers methane from kitchen waste and paper contained in the municipal waste. Currently, municipal waste is collected as a mixture of components such as paper, kitchen waste, plastics, glass, metal, and wood chips. However, incinerating municipal waste containing garbage with a high moisture content not only causes failure of the incineration equipment, but also consumes heavy oil as an auxiliary fuel during the summer when the moisture content is high. As an alternative to the above-mentioned incineration method, research into new processing methods whose main purpose is to recover the useful components themselves or to recover fuel oil together with fuel gas is becoming more active.
One way to recover the latter energy is to mechanically separate the mixed garbage into two fractions: kitchen waste and plastics, then process the former to undergo methane fermentation to produce methane gas, and pyrolyze the latter to recover fuel oil. There is something that says. However, mechanical separation techniques that utilize differences in specific gravity, mechanical strength, or magnetism, or a combination of these, do not allow other components such as paper, glass, and metals to mix into kitchen waste or plastics. I can't put it down. This is because during the garbage collection and primary crushing process, agglomerates containing paper, earth, sand, non-ferrous metals, etc. are formed with wet kitchen waste as the core, making it difficult to clearly separate them using conventional mechanical separation methods. When these other components are mixed in, the following disadvantages occur.In other words, regarding methane fermentation of kitchen waste, if European plastics such as expanded polystyrene and polyethylene are mixed into kitchen waste,
These particles float on the liquid surface of the methane fermentation tank in a layered manner, and toss scum is likely to occur. At this time, ``Even if you try to extract it from the system, it must be done inside the tank under anaerobic conditions, which is extremely difficult due to the structure.On the other hand, if paper gets mixed in, methane fermenting bacteria cannot decompose paper fibers under normal conditions, so This will result in negative pressure in Takahai, and the amount of digested sludge by-product will increase.Furthermore,
If glass, butterflies, non-ferrous metals, etc. get mixed in, they will solidify at the bottom of the tank.
They become compacted and it becomes extremely difficult to extract them from the bottom while maintaining an anaerobic state. On the other hand, if paper is mixed into the plastics fraction, not only will energy be lost due to the amount of water in the paper during pyrolysis, but the pyrolysis of the paper will produce by-product wood tar, which has low utility value and is difficult to process. There is. On the other hand, as a separation method, in addition to the dry separation method described above, a green separation method is also known. This involves adding water to mixed collected waste to form a slurry, which is then separated based on the difference in specific gravity. First, a slurry with a solid content concentration of 4% or less is made, and a high-speed mixer is used to crush the fiber components and other solids into a porridge-like slurry. Next, a liquid cyclone is used to separate the car fluid, which contains solid materials with a high specific gravity such as metals, glass, and rocks, into a light fluid, which contains paper fibers, kitchen waste, plastics, etc., which have a smaller specific gravity. The difficulty is that the slurry concentration must be reduced to 4 because it is crushed and subjected to a liquid cyclone.
I can't give more than %. Therefore, even if an attempt is made to treat light liquid with methane fermentation, the concentration is low and it is not suitable for methane fermentation. Therefore, a large amount of high BOD wastewater is discharged.Furthermore, the power consumption for crushing and separation is large, and the high-speed moving parts are extremely worn, making it impractical.
The purpose of the present invention is to "eliminate the drawbacks of the above-mentioned prior art"
The object of the present invention is to provide a solid waste treatment method with excellent energy recovery using methane fermentation as an elemental technology. The first aspect of the present invention is to treat a slurry prepared by adding water to mixed collected garbage with cellulase (cellulose hydrolase) to make the cellulose fibers in the slurry finer, and then create a floating layer, kitchen waste and The slurry is separated into an intermediate layer containing fine synthetic fibers and a sedimentation layer, and the intermediate layer is fermented using cellulose-degrading methane-fermenting bacteria. Oxygen treatment. If the slurry is sedimented and separated without the enzyme treatment in the present invention, the solids concentration of the slurry must be reduced to 3% or less. In the present invention, the solids concentration must be reduced to 15% or less by the enzyme treatment.
% slurry can be easily fractionated. Second aspect of the present invention
is in the separated layer obtained by the same specific gravity separation as above,
Separate the intermediate layer into solid-liquid, separate the solid material containing pulp and the liquid containing cellulase, subject the solid material containing pulp to methane fermentation treatment, and use the liquid containing cellulase as cellulase and water for use in the enzyme treatment step. It is used repeatedly. In the present invention, expensive enzymes can be effectively recycled without being thrown away. The factors are enzyme concentration, reaction temperature and reaction time, and it is essential to carry out the process under the conditions shown in Figure 1 due to the characteristics of the mixed waste collected; it has been found that carrying out the process under other conditions will result in various disadvantages. Examples are shown below and explained in more detail. First, mixed municipal waste (50% moisture, 12% kitchen waste, 25% paper, 5% plastics, 2% metals, 6% others) A slurry with a solid concentration of 15% was prepared by adding water to the slurry.Cellulase was added to this slurry at a concentration of 1 x 1 P unit (furnace paper disintegration activity)/k9 cellulose, which was within the effective enzyme concentration range.
The reaction was carried out at 0°C. As a result, as shown in FIG. 2, the average length of the fibers was reduced to 1/5 after 1 hour, and it was possible to efficiently refine the fibers. During this time, the pH does not change significantly and the enzyme activity only slightly decreases. Therefore, it becomes possible to collect the aqueous layer fraction and reuse it as an enzyme solution. That is, the slurry after 3 hours of enzyme treatment was transferred to a beaker, left undisturbed for 30 minutes to settle the fibers, and the liquid fraction was collected by decantation. Next, this was made into an enzyme solution, and municipal waste as a raw material was added to the solution so that the solids concentration became 15%, and the reaction was carried out under the same conditions as above. As a result, as shown in FIG. 3, almost the same results as in FIG. 1 were obtained, and the authors found that expensive enzymes could be reused rather than disposable. If the enzyme concentration is higher than the above preferred concentration, for example, 1 unit/k
When added to 9 cellulose, disadvantages occur as shown in FIG. In other words, the fiber length decreases by 1/5 within 20 minutes.
However, the enzyme rapidly deactivates. This not only shortens the fibers, but also decomposes them into reducing sugars.The lactic acid fermentation action of lactic acid bacteria mixed in the waste changes the reducing sugars into lactic acid, rapidly acidifying the reaction solution, and enzymatically This is because it denatures and coagulates and precipitates. This makes it impossible to recycle the enzyme and increases processing costs. Not only that, but when reducing sugar changes to lactic acid, the previous application (Tokugan 5th century)
4-49751), the methane yield in the subsequent methane fermentation step decreases. On the other hand, even if the enzyme concentration is lower than the above-mentioned concentration, the following disadvantages occur. For example, when 1 unit/k9 cellulose is added, as shown in Figure 5, the cutting of paper fibers is extremely slow, and during this time kitchen waste components in the garbage are converted to acid by lactic acid bacteria and fatty acid fermenting bacteria. pH decreases. For this reason,
The enzyme is deactivated before the fiber becomes short. On the other hand, regarding the reaction temperature, at 18'0, the reaction rate is low and it takes a long time to shorten the fibers. In addition, at high temperatures of 1,000°C or more, enzymes tend to be inactivated by heat (making it difficult to reuse enzymes. If the reaction time is less than 10 minutes, the enzyme concentration will be 1 p unit/unit).

[Even with cellulose 9, the fibers are not cut enough,
If the time exceeds 6 hours, the enzyme tends to be inactivated due to a drop in pH. Therefore, when enzymatically treating a slurry of solid waste, the solid concentration is kept at 15% or less, cellulase is added to this slurry, and the enzyme concentration is 1 x 1 p - 1 x 1 paper disintegrating activity/k9 cellulose. , reaction temperature 18-70qo,
By setting the reaction time to 1 minute to 6 hours, it is possible to shorten the cellulosic fibers and at the same time maintain the enzyme activity, thereby enabling efficient methane fermentation and recycling of the enzyme. Next, an embodiment of the present invention will be described in more detail based on FIG. First, mixed collected municipal waste (solid waste) 1 is collected in storage tank 2.
to be stored. Next, magnetic metals 4 such as iron and stainless steel are removed by a magnetic centrifuge 3, and crushed by a crusher 5 to a particle size of 5 ribs or less. This is because if the particle size of the raw material is too large, enzyme treatment cannot be carried out smoothly. The crushed raw material is put into a sorting tank 101. At the same time, cellulase 6 from cellulase storage tank 7 and water 8 from water storage tank 9 are supplied to fractionation tank 10 and treated under the conditions of temperature, pH, and residence time shown in FIG. Enzyme treatment safely converts paper fibers into short fibers.
Light plastics such as polyethylene and polypropylene, plastic foams, wood chips, and other materials having a specific gravity of 1 or less float on the liquid surface and form a floating layer fraction 11. On the other hand, non-magnetic metals, pottery pieces, glass pieces, sand machines, heavy plastics such as vinyl chloride, etc., easily settle on the bottom of the sand as a sediment layer fraction 13. An intermediate layer fraction 12 is formed between the floating layer fraction 11 and the settling layer fraction 13 as a suspended slurry of short fiber paper and kitchen waste particles. Here, the floating layer fraction 11 and the settling layer fraction 13 are each extracted from the separation layer 10 to the outside of the system. If necessary, the floating layer fraction 11 may be further separated into plastic foam, vertical plastics, and water-containing wood chips by a method utilizing a difference in specific gravity such as wind power or a rotary table after washing and draining. After these three components are separated, the plastics can be thermally decomposed into fuel oil and fuel gas, or they can be melted and recycled.The sedimentation fraction 13 can also be converted into metals by underwater specific gravity differentiation using specific gravity differences, if necessary. The plastics can be classified into glass, sandy rocks, and plastics.The plastics may be combined with the plastics in the floating layer fraction 11 and subjected to thermal decomposition and melting regeneration. It can be carried out either batchwise or continuously.The intermediate layer fraction 12 is transferred to the settling tank 14 via the intermediate layer transfer piping 30, and the aqueous layer fraction 15 and pulp layer fraction 16 are
Separate into A part of the aqueous layer fraction 15 containing cellulase is returned as separated water and cellulase through an aqueous fraction transfer piping 18 and an aqueous fraction return piping 19, and is also sent to an anaerobic digestion tank (methane fermentation) together with the pulp layer fraction 16. (tank) Pour 20 tons,
Perform methane fermentation treatment. As the fermentation bacteria, a group of fermentation bacteria that decompose cellulose is used. By using cellulose-degrading fermentation bacteria, not only easily decomposable organic substances such as glycoproteins and lipids derived from kitchen waste, but also cellulose can be converted into methane. Among the bacterial groups that can be used, examples of liquefaction bacteria that convert organic matter into volatile fatty acids include Clostridium, Pacillus, Escherichia, and the like. Examples of gasifying bacteria that convert volatile fatty acids into methane include Methanococcus, Methanosarcina, and Methanobacterium. The fermentation process may be a conventional fermentation method that mixes liquefaction fermentation and gasification fermentation (one-phase method, mixed fermentation method), or a method that separates liquefaction fermentation and gasification fermentation (two-phase method). Conventionally known fermentation conditions such as fermentation temperature are sufficient. That is, the temperature is 15-70
oo, if the volume load of organic matter is 30k9 organic matter/effective volume of the fermenter, it can be sufficiently treated. The composition of the gas generated varies depending on the fermentation method and fermentation conditions mentioned above, but
Contains 40-90% methane and 10-60% carbon dioxide, as well as significant amounts of hydrogen sulfide, hydrogen and nitrogen.The amount of fermentation gas generated varies depending on the quality of the raw materials and fermentation conditions.
The organic substance k9 is in the range of 180 to 360 in terms of pure methane. The fermentation gas is transferred to a desulfurization tower 23 via a transfer pipe 22.
The gas is then desulfurized and stored in the gas storage tank 24. This fermentation gas has a relatively high calorific value of 3,500 to 7,000 Kcal. This fermentation gas can also be used as fuel for the heating boiler of this process and the gas engine generator of the Azusa thermal power plant. The fermented slurry passes through a transfer pipe 25 and is mixed with a desorbed liquid (treated water) 27 and digested sludge 28 in a settling tank 26.
and are separated and processed using known processing techniques.
Next, Examples and Comparative Examples will be shown to explain the effects of the present invention in more detail. Example 1 30 pieces of municipal waste 6K9 having the composition shown in Table 1, which had been primarily crushed to a maximum particle size of 5 or less, was placed in a polyacrylic resin tank, and 19 pieces of water was added to make a raw material slurry with a solid content concentration of 12%. Prepare. The above slurry has cellulose decomposition activity (furnace paper disintegration activity)
20 kg of microbial cellulase (Trichoderma spp.) equivalent to 1 x 1 unit per cellulose lk9.
and treated at 19oC for 6 hours under a Yurufuji terrace Azusa. Table 2 shows the fiber length, pH, and enzyme activity residual rate before and after treatment. After treatment, let stand for 1 minute to remove floating layer, middle layer,
Fractionate into 3 fractions of sediment layer. The floating layer and the settling layer are separated into solid and liquid using wire mesh furnace material, and the liquid is combined with the intermediate layer. The weight of each fraction after the above solid-liquid separation operation was 1.5 kg for the floating layer, 22 kg for the intermediate layer, and 1.5 kg for the sedimented layer, and the composition thereof is shown in Table 3. Light plastics and wood and bamboo are almost completely recovered in the floating layer fraction. Heavy plastics, metals, glass, and sandy rocks are recovered almost quantitatively. Kitchen waste and paper fibers are recovered in finely divided and dissolved form in the intermediate fraction. On a dry basis, the mixing rate of impurities other than paper and kitchen waste in the intermediate layer fraction is 2%. Next, 3k of the above middle layer fraction
9 and effective volume 10 with digested slurry 7k9.
The mixture was put into the cylindrical fermenter, and batch fermentation was carried out at 60°C under anaerobic conditions with slow lighting. The digested slurry used as a seed mother is made from the above intermediate tank fraction, and contains 6
Contains a group of methane-fermenting bacteria with high cellulose-degrading activity that are familiar with 000. The fermentation gas generated during fermentation was measured over time, and the fermentation was completed after about 10 days, yielding 19.5 ml of methane. Therefore, the amount of methane recovered from the intermediate fraction is 143 soybeans. Table 1 Table 2 Table 3 Example 2 Using the same batch of municipal waste as in Example 1, the solid content concentration was 12.
% raw material slurry is prepared. The above slurry has cellulose decomposition activity (furnace paper disintegration activity)
1 of the same batch of enzyme used in Example 1 as
x 1 cellulose/k9 cellulose (20 minutes) and treated for 10 minutes at 48oo under Ayasataka Azusa. Table 4 shows the fiber length, pH, and enzyme activity residual rate before and after treatment. After the treatment, in the same manner as in Example 1, a floating layer of 1.6k9,
Three fractions are separated: an intermediate layer of 21.6k9 and a sedimentary layer of 1.8k9. Its composition is shown in Table 5. Light plastics, styx and bamboos are almost completely recovered in the floating layer fraction. Heavy plastics, metals, glass and metals are also recovered almost quantitatively in the sediment fraction. Kitchen waste and fibers are recovered in finely divided and dissolved form as an intermediate fraction. On a dry basis, the rate of contamination of impurities other than paper and kitchen waste into the intermediate layer fraction is 5%. Further, under these conditions, the pH of the slurry does not decrease significantly, the enzyme is not deactivated, and if the intermediate layer is solid-liquid separated, the liquid fraction can be reused as an enzyme solution. Next, 3k9 of the above intermediate layer fraction is separated and subjected to anaerobic digestion in the same manner as in Example 1. Fermentation ends after about 10 days, and methane is 19.5
That's what you get. Therefore, the amount of methane recovered from the intermediate fraction is 143 soybeans. Table 4 Table 5 Example 3 Using the same batch of municipal waste as in Example 1, the solid content concentration was 12.
% raw material slurry is prepared. The above slurry has cellulose decomposition activity (furnace paper disintegration resistance)
The same batch of enzyme used in Example 1 was added to a concentration of 1 x 1 unit/k9 cellulose (0.2 units) and treated under a slow light at 43oo for 360 minutes.
Table 6 shows the fiber length, pH, and enzyme activity residual rate before and after treatment.
Shown below. After the treatment, in the same manner as in Example 1, a floating layer of 1.5
Three fractions are separated: k9, intermediate layer 2149k9, and sedimentary layer 1.6k9. Its composition is shown in Table 7. Bulky plastics and bamboos are almost completely recovered in the floating layer fraction. Automobile plastics, metals, glass and dirt are also almost quantitatively recovered in the sedimentation fraction. Kitchen waste and fibers are recovered in finely divided and dissolved form as an intermediate fraction. On a dry basis, the rate of contamination of impurities other than paper and kitchen waste into the intermediate layer fraction is 2%. Furthermore, under these conditions, the - of the slurry does not decrease significantly, the enzyme does not become inactivated, and the liquid fraction can be reused as an enzyme solution by separating solid and liquid from the intermediate layer. Next, 3k9 of the above intermediate layer fraction was separated and subjected to magnetic digestion in the same manner as in Example 1. After about 10 days, the fermentation was completed and 19
．． You can get 3 points. Therefore, the amount of methane recovered from the middle layer fraction is 141. Table 6 Table 7 Example 4 Using the same batch of municipal waste as in Example 1, solid matter concentration 1
Prepare a 2% raw material slurry. The above slurry has cellulose decomposition activity (furnace paper disintegration activity)
As follows, the same batch of enzyme used in Example 1 was added to a concentration of 1 x 1 unit/k9 cellulose (0.2 units) and treated at 600°C for 10 minutes. . Table 8 shows the fiber length, state, and enzyme activity residual rate before and after treatment. After the treatment, in the same manner as in Example 1, a floating layer of 1.5k9
, an intermediate layer of 21.8 kg, and a sediment layer of 1.7 kg. Its composition is shown in Table 9. Light plastics and wood and bamboo are almost completely recovered in the floating layer fraction. Heavy plastics, metals, glass and rock are also almost quantitatively recovered in the sediment fraction. Kitchen waste and fibers are recovered in finely divided and dissolved form as an intermediate fraction. On a dry basis, the rate of contamination of impurities other than paper and kitchen waste into the intermediate layer fraction is 3.5%. Also,
Under these conditions, the pH of the slurry does not drop significantly and the enzyme is not deactivated, and if the intermediate layer fraction is solid-liquid separated, the fraction can be reused as an enzyme solution. Next, 3k9 of the above intermediate layer fraction is separated and subjected to anaerobic digestion in the same manner as in Example 1. Fermentation ends after about 10 days,
19.3 ml of methane was obtained. Therefore, the amount of methane recovered from the middle layer fraction is 140 units. Table 8 Table 9 Example 5 Using the same batch of municipal waste as in Example 1, solid matter concentration 1
Prepare a 2% raw material slurry. The above slurry has cellulose decomposition activity (furnace paper disintegration activity)
Then, the same batch of enzyme as used in Example 1 was added to a concentration of 1 x 1 unit of cellulose (2 hours) and treated at 45°C for 90 minutes under a hot flashlight. The fiber length, pH, and enzyme activity residual rate before and after the treatment are shown in Table 10.After the treatment, in the same manner as in Example 1, a floating layer of 1.5k9
, an intermediate layer of 21.9k9, and a sedimentary layer of 1.6k9. Its composition is shown in Table 11. Vertical plastics and trees and bamboos are almost completely recovered in the floating layer fraction. Heavy plastics, metals, glass and rock are also almost quantitatively recovered in the sediment fraction. Kitchen waste and fibers are recovered in finely divided and dissolved form as an intermediate fraction. On a dry basis, the rate of contamination of impurities other than paper and kitchen waste into the intermediate layer fraction is 20%. Also,
Under these conditions, the pH of the slurry does not drop significantly, the enzymes are not deactivated, and the intermediate layer fraction can be reused as a liquid fraction by solid-liquid separation. Next, 3k9 of the above intermediate layer fraction is collected and subjected to anaerobic digestion in the same manner as in Example 1. Fermentation is completed after about 10 days and 19.2 ml of methane is obtained. Therefore, the amount of methane recovered from the intermediate fraction is 140 soybeans. Table 10 Table 11 Example 6 30 pieces of municipal waste 7K9 (moisture content 42%) having the composition shown in Table 12, which had been primarily crushed to a maximum particle size of 5 mm or less, was placed in a polyacrylic resin tank, and 20.1 mm of water was added. By adding it, a raw material slurry having a solid content concentration of 15% is prepared. Cellulase prepared from Asbergillus niger was added to the above slurry as a furnace paper disintegrating activity at a cellulose concentration of 1 x 1 unit/k9 (25 minutes), and the mixture was poured into a 45q0
Process with 2 flours. Fiber length, pH before and after treatment,
Table 13 shows the enzyme activity residual rate. After the treatment, the mixture was allowed to stand for 1 minute and separated into three fractions: a floating layer, an intermediate layer, and a sedimented layer. The floating layer and the settling layer are separated into solid and liquid using wire mesh furnace material, and the liquid is combined with the intermediate layer. The weight of each fraction after the solid-liquid separation operation is 1.4k9 for the floating layer and 23.3k9 for the intermediate layer.
, the sedimentation layer was 2.4k9, and its composition is shown in Table 14.
Light plastics and wood and bamboo are almost completely recovered in the floating layer fraction. Heavy plastics, metals, glass and sand machines are also recovered in almost quantitative amounts. Kitchen waste and paper fibers are recovered in finely divided and dissolved form in the intermediate fraction. On a dry basis, the rate of contamination of impurities other than paper and kitchen waste into the intermediate layer fraction is 5%. Next, 3k9 of the above-mentioned intermediate layer fraction was fractionated, and the digested slurry was
A cylindrical fermentation bed with an effective volume of 7k9 was charged to 10 ml, and batch fermentation was carried out at 6000 ml under anaerobic conditions with constant speed. The digested slurry used as a seed mother is made from the above-mentioned intermediate layer fraction and contains a group of fermenting bacteria with high cellulolytic activity that have been acclimated to ~60 qo. If the fermentation gas generated during fermentation is measured over time, the fermentation will end after about 10 days and 27 tons of methane will be obtained. Therefore, the amount of methane recovered from the intermediate fraction is 210 units. Table 12 Table 13 Table 14 Comparative example 1 Using the same batch of municipal waste as in Example 1, solid concentration 12%
Prepare a raw material slurry. This raw material slurry is treated as it is under the conditions of Example 1 without adding any enzyme. Table 15 shows the fiber length and pH before and after treatment. No major changes were observed in fiber length or pH. After treatment, 1.9 kg of floating layer was prepared in the same manner as in Example 1.
, an intermediate layer 21k9, and a sedimentary layer 2.1k9. Its composition is shown in Table 16. Each component was not clearly separated compared to each example, and the component composition of the intermediate layer fraction was similar to that of the raw material waste slurry (Table 1). Incidentally, on a dry basis, the rate of impurities other than paper and kitchen waste mixed into the intermediate layer fraction was 32%. Next, 3k9 of the above intermediate layer fraction is separated and subjected to anaerobic digestion in the same manner as in Example 1. Fermentation is completed after about 10 days and 14.9 units of methane are obtained. Therefore, the amount of methane recovered from the middle layer fraction is 104 SO. Table 1
5 Table 16 Comparative Example 2 The intermediate layer fraction 3k9 of Comparative Example 1 was collected and put into a cylindrical fermentation layer with an effective volume of 10 containing the digested slurry 7k9 described below, and was heated under anaerobic conditions while exfoliating. 60
Perform batch fermentation at oo. The digested slurry used as the seed material is made from a slurry of 10% solid content from separately collected kitchen waste and is acclimatized for more than 6 months, and contains methane-fermenting bacteria with no cellulolytic activity. Measuring the fermentation gas generated during fermentation over time shows that the fermentation ends after about 10 days and 7.8 tons of methane is obtained. Therefore, the amount of methane recovered from the intermediate layer fraction was 54.4, which was 38% of Example 1 and 50% of Comparative Example 1. Comparative Example 3 Using the same batch of municipal waste as in Example 1, a raw material slurry with a solids concentration of 12% was prepared. The above slurry has cellulose decomposition activity (furnace paper disintegration activity)
The same batch of enzyme as used in Example 1 was added to a concentration of 2 x 1 unit/k9 cellulose and treated at 100° for 800 minutes under a slow pressure. Table 17 shows the fiber length, pH, and enzyme activity residual rate before and after treatment. After the treatment, in the same manner as in Example 1, it was separated into three fractions: a floating layer of 1.7 kg, an intermediate layer of 21.2 kg, and a sedimented layer of 2.1 kg. Its composition is shown in Table 18. Each component was not clearly separated in each example, and the component composition of the intermediate layer fraction was similar to that of the raw material waste slurry (Table 1). Incidentally, on a dry basis, the rate of contamination of impurities other than paper and kitchen waste in the intermediate layer fraction was 26%. Next, 3k9 of the above intermediate layer fraction is separated and subjected to anaerobic digestion in the same manner as in Example 1. Fermentation is completed after about 10 days and 15.9 tons of methane is obtained. Therefore, the amount of methane recovered from the middle layer fraction is 113 m2.
% raw material slurry is prepared. The above slurry has cellulose decomposition activity (furnace paper disintegration activity)
The same batch of enzyme as used in Example 1 was added to a concentration of 9 x 1 unit/k9 cellulose (0.18 units) and treated for 800 minutes at 4 degrees Fahrenheit for 800 minutes. Table 19 shows the fiber length, pH, and enzyme activity residual rate before and after treatment.
After the treatment shown in , a floating layer of 1.8k9 was prepared in the same manner as in Example 1.
, an intermediate layer of 21.2k9, and a sedimentary layer of 2.0k9. Its composition is shown in Table 20. Each component was not clearly separated compared to each example, and the component composition of the intermediate layer fraction was similar to that of the raw material waste slurry (Table 1). Incidentally, on a dry basis, the rate of contamination of impurities other than paper and kitchen waste in the intermediate layer fraction was 26%. Next, 3 kg of the above-mentioned intermediate layer fraction is separated and subjected to anaerobic digestion in the same manner as in Example 1. Fermentation is completed after about 10 days and 15.6 ml of methane is obtained. Therefore, the amount of methane recovered from the middle layer fraction is 110 units. Table 19 Table 20 Comparative Example 5 Using the same batch of municipal waste as in Example 1, the solid content concentration was 12.
% raw material slurry is prepared. The above slurry has cellulose decomposition activity (furnace paper disintegration activity)
The same batch of enzyme used in Example 1 was added to a concentration of 2 x 1 units/kg cellulose (0.4 units) and treated at 75°C for 900 minutes under slow simmering conditions. Table 21 shows the fiber length, pH, and enzyme activity residual rate before and after treatment.
Shown below. After treatment, a floating layer of 1.6k was formed in the same manner as in Example 1.
9. Separate into 3 fractions: intermediate layer 21.6 kg, and sediment layer 1.8 kg. Its composition is shown in Table 22. Each component was not clearly separated in comparison with each example, and the component composition of the intermediate layer fraction was similar to that of the raw material waste slurry (Table 1). Incidentally, on a dry basis, the rate of contamination of impurities other than paper and kitchen waste in the intermediate layer fraction was 26%. Next, 3k9 of the upper middle layer fraction was fractionated, and Example 1
Perform anaerobic digestion in the same manner as. After about 10 days, the fermentation is completed and 5.7 tons of methane is obtained. Therefore, the amount of methane recovered from the intermediate fraction is 113 soybeans.
Table 21 Table 22 Comparative Example 6 Using the same batch of municipal waste as in Example 1, the solid content concentration was 12.
% raw material slurry is prepared. The above slurry has cellulose decomposition activity (furnace paper disintegration activity)
The same batch of enzyme as used in Example 1 was added to a concentration of 1 x 1 cellulose/k9 cellulose (20 cells) and treated under the open ocean at 65°C for 4 minutes. Before processing,
Table 23 shows the fiber length, pH, and enzyme activity residual rate after treatment. After the treatment, in the same manner as in Example 1, it is separated into three fractions: 1.5 kg of floating layer, 21.4 kg of intermediate layer, and 18 kg of sedimented layer. Its composition is shown in Table 24. Each component was not clearly separated compared to each example, and the component composition of the intermediate layer fraction was similar to that of the raw material waste slurry (Table 1). The rate of contamination of foreign matter other than paper and kitchen waste in the intermediate layer fraction on a dry basis was 26%. Next, 3k9 of the above intermediate layer fraction is separated and subjected to anaerobic digestion in the same manner as in Example 1. Fermentation is completed after about 10 days and 16.9 ml of methane is obtained. Therefore, the amount of methane recovered from the intermediate fraction is 121 units. Table 23 Table 24 As mentioned above, the maximum slurry concentration that can be applied to the conventional wet sorting method is 4%, but in the present invention, the slurry concentration that can be applied to wet sorting can be increased to a high concentration of 15% by enzyme treatment. It is possible to carry out wet separation with high precision, and it is also possible to minimize the amount of impurities that are unnecessary for methane fermentation in the intermediate layer used for methane fermentation, thereby reducing the generation of scum and subsequent deposits. can prevent the accumulation of methane and perform efficient methane fermentation.

[Brief explanation of drawings]

Figure 1 is a diagram showing the enzyme concentration, reaction temperature and reaction time conditions during enzyme treatment in the present invention, Figures 2, 3 and 4.
5 and 5 are diagrams showing changes over time in enzyme activity, pH value, fiber length, and lactic acid concentration under predetermined enzyme concentration conditions,
FIG. 6 is a flow sheet showing an example of the present invention. 1... Raw material municipal waste, 2... Raw material municipal waste storage tank, 3
... Magnetic separator, 5... Crushing machine, 7... Cellulase storage tank, 9... Water storage tank, 10... Sorting tank, 14...
- Sedimentation separation tank, 20... Anaerobic digestion tank (methane fermentation tank), 23... Desulfurization tower, 24... Gas storage tank, 26... Sedimentation tank. Fig. 2 Fig. 3 Atsumu Fig. Fig. 6

Claims (1)

[Scope of Claims] 1. A first step of crushing solid waste mainly composed of paper, kitchen waste, and at least one of plastics, glass, gravel, metal, and wood chips; 2. In the first step. Water is added to the crushed solid waste to make a slurry with a solid concentration of 15% or less, and cellulase is added to this slurry to give an enzyme concentration of 1 x 10^3 to 1 x 10^5 filter paper disintegrating activity/kg cellulose, reaction. Temperature: 18-70℃, reaction time: 10 minutes-6
a second step of enzymatic treatment under conditions of 3 hours; a third step of separating the slurry subjected to the enzyme treatment in the second step into a floating layer, an intermediate layer and a settling layer based on the difference in specific gravity;
A fourth step of anaerobically decomposing the short cellulose fibers obtained in the third step and an intermediate layer containing kitchen waste into methane and carbon dioxide using cellulose-degrading methane-fermenting bacteria. processing method. 2 1. A first step of crushing solid waste mainly composed of paper, kitchen waste, and at least one of plastics, glass, gravel, metal, and wood chips; 2. Water was added to make a slurry with a solid concentration of 15% or less, and cellulase was added to this slurry to give an enzyme concentration of 1 x 10^3 to 1 x 10^3 filter paper disintegrating activity/kg cellulose, reaction temperature of 18 to 70°C, Reaction time 10 minutes ~ 6
3. A third step in which the slurry treated with the enzyme in the second step is separated into a floating layer, an intermediate layer, and a settling layer based on the difference in specific gravity; 4. The slurry obtained in the third step The intermediate layer is solid-liquid separated into a solid containing pulp and a liquid containing cellulase, and the solid containing pulp is supplied to the fifth step below, and the liquid containing cellulase is supplied to the second step. 4 steps; and 5 steps of anaerobically decomposing the solid material containing pulp supplied from the fourth step into methane and carbon dioxide using cellulose-degrading methane-fermenting bacteria. Method.