Method for treating high-concentration organic waste

Abstract

To efficiently carry out fermentative decomposition of high concentration organic waste such as waste of activated sludge having treated sewage and livestock excreta.SOLUTION: A method of treating high concentration organic waste is characterized in that a mixture of the high concentration organic waste and a support is adjusted to have a C / W ratio in a range of 2.00 to 2.50, preferably at 2.18, with C representing the heat quantity of the high concentration organic waste and W representing the latent heat of vaporization of the high concentration organic waste, upon fermentatively decomposing a mixture of high concentration organic waste such as concentrated sewage sludge and a support such as a weed, under an aerobic condition, whereby a high volume reduction ratio and reduction of odor can be achieved.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for decomposing high-concentration organic waste, such as concentrated sewage sludge, by aerobic fermentation. [Background technology]

[0002] Generally, high-concentration organic wastes include not only concentrated sewage sludge as mentioned above, but also a variety of other wastes, such as food waste discarded from restaurants and home kitchens, shochu wastewater discarded from food and beverage processing plants, bean-jam manufacturing waste, livestock manure from pigs and cows, chicken droppings, and dehydrated blue-green algae sludge recovered from lakes and rivers. Today, disposing of these wastes without treatment is strictly regulated from the standpoint of causing pollution, and there is a demand for efficient treatment of such high-concentration organic wastes without causing pollution. However, since such high-concentration organic waste contains a large amount of water, it is not suitable for incineration at an incineration plant, so a method is known in which the organic waste is placed on a support such as cedar chips to create a mixture (colony), and the colony is then agitated while being decomposed by fermentation using aerobic bacteria (see, for example, Patent Document 1).This method, which employs an improved agitation device, makes it possible to reliably perform fermentation treatment of organic waste, and is still highly regarded today. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Patent Publication No. WO2011-052182 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the conventional methods simply involve natural fermentation of a mixture (colony) of organic waste mixed with a support, without considering the properties of the mixture. As a result, the amount of fermentation that can be achieved varies depending on the properties of the mixture. For example, if there is too much moisture, the moisture will inhibit the supply of oxygen, preventing aerobic fermentation from progressing, and instead may result in anaerobic fermentation (putrefaction). On the other hand, if there is too much high-concentration organic waste, the aerobic fermentation will progress slowly, and it may take a long time to reduce the volume. These are the problems that the present invention aims to solve. [Means for solving the problem]

[0005] The present invention has been created in view of the above-mentioned circumstances and with the aim of solving these problems. The invention of claim 1 is as follows: The organic wastes are selected from the group consisting of concentrated sewage sludge, food waste, shochu waste, anko (bean paste) manufacturing waste, livestock manure, chicken manure, and dehydrated blue-green algae sludge, and plants that respond to soil disturbance, such as weeds, cedar chips, rice bran, rice husks, and sawdust, either alone or in combination. Mixed with the support mixture When decomposing the above by fermentation under aerobic conditions, organic waste and the support mixture organic waste The heat energy of C, organic waste The method for treating organic waste is characterized in that, when the latent heat of vaporization of the organic waste is represented by W, the C / W ratio is adjusted to be in the range of 2.00 to 2.50. The invention of claim 2 is a C / W ratio The adjustment is 2.18 2. The method for treating organic waste according to claim 1. The invention of claim 3 is a C / W ratio Adjustment in the range of 2.00 to 2.50 is required if the value is higher than the range. Adding water This is an adjustment by , and low energy materials The soil is adjusted by adding waste cooking oil, food waste, rice bran, and weeds that can cope with soil disturbance. 2. The method for treating organic waste according to claim 1. [Effects of the Invention]

[0006] By adopting the invention of claim 1, organic waste The mixture of the carrier and the cellulose is decomposed by aerobic bacteria. fermentation In this case, organic waste The heat energy of C, organic waste When the latent heat of vaporization of the waste is W, the C / W ratio is adjusted to be in the range of 2.00 to 2.50, thereby facilitating fermentation and decomposition by aerobic bacteria under optimal conditions. By adopting the invention of claim 2, the C / W ratio is It will be 2.18 This will promote more efficient aerobic fermentation decomposition under optimal conditions. According to the invention of claim 3, when the C / W ratio is high, it can be adjusted by adding water, and when it is low, it can be adjusted by adding a support, so that adjustment can be easily performed. DETAILED DESCRIPTION OF THE INVENTION

[0007] Next, an embodiment of the present invention will be described. organic waste Examples of such waste include concentrated sewage sludge generated during the process of treating sewage water, food waste discarded from restaurants and home kitchens, shochu wastewater discarded from food and beverage processing plants, bean paste waste, livestock manure from pigs and cows, chicken droppings, and dehydrated blue-green algae sludge recovered from lakes and rivers. Even if the waste has a high water content before being dehydrated, it can be treated as is in the present invention. organic waste It can be used as:

[0008] In carrying out the present invention, organic waste The fermentation process is carried out by aerobic bacteria, and as with normal natural fermentation, these aerobic bacteria are those that naturally adhere to a support (support, carrier), and there is no need to add special aerobic bacteria. Cedar chips are selected as such a support, as their porous nature promotes the growth of aerobic bacteria. However, rice bran, rice husks, waste (sawdust) from sawmills, etc. can also be used alone, or a mixture (colony) of these appropriately mixed together. Furthermore, weeds (wild grasses) are suitable carriers for carrying out the present invention. , plants that respond to soil disturbance ) are exemplified, but these weeds are preferable because they are made of fine fibers and when piled up, they become fluffy, not only improving moisture regulation and breathability but also providing excellent heat retention, and the weeds generated during weeding work can be effectively used as a carrier.

[0009] The present invention provides organic wasteThe purpose of this study was to quickly decompose and reduce the volume of the waste by fermentation using aerobic bacteria. organic waste The rate of decomposition varies depending on the amount of water, while the amount of water serves as a nutrient source for aerobic bacteria to grow and promote the decomposition process. organic waste It is inferred that the calorific value of the water is related to the amount of nutrients that aerobic bacteria need to grow. organic waste When the C / W ratio, which is the ratio of the heat quantity (calorie content) C of the mixture of the catalyst and the carrier to the latent heat of vaporization W converted from the water content of the mixture, is in the range of 2.00 to 2.50, organic waste The present inventors have confirmed that the decomposition of lactic acid bacteria by aerobic fermentation is promoted, and have completed the present invention. If the C / W ratio is lower than 2.00, the moisture content is too high. Amount of organic waste If the moisture content is too low, there will be a lack of energy and oxygen to activate aerobic bacteria, which will inhibit the promotion of aerobic fermentation. Conversely, if the moisture content is higher than 2.50, the moisture content will be low, Amount of organic waste It is presumed that the activity of aerobic bacteria is reduced due to excessive amounts of fermentation, thereby inhibiting the promotion of aerobic fermentation.

[0010] Therefore, if the C / W ratio of the mixture to be fermented is lower than 2.00, it is determined that the water content is too high. waste cooking oil The C / W ratio is adjusted by adding high-energy materials such as food waste and rice bran, but these high-energy materials also include the weeds that serve as carriers as mentioned above. If the C / W ratio of the mixture exceeds 2.50, it is determined that there is a water shortage, and water is added to adjust the C / W ratio to within the range of 2.00 to 2.50. Incidentally organic waste The calorific value C of the mixture of the catalyst and the carrier can be measured using a commercially available calorie calculator, and the latent heat of vaporization can be calculated from the water content of the mixture. Since no special equipment or technology is required, details of the calculation method will be omitted here.

[0011] Next, experimental examples of the present invention will be described together with comparative examples.

[0012] <Experiment 1> organic waste The feces and urine of cattle raised in barns on a ranch were selected as the target material, and weeds (wild grasses) growing on the ranch (outdoors) were collected as the carrier, and these were mixed to obtain a mixture. By adjusting the mixing ratio of the manure and the weeds in this mixture, the C / W ratios of 1.50, 2.00, 2.18, 2.50 and 3.00 were obtained (Experiment Nos. 1 to 5). 10 kg of each of these mixtures was placed in a 30 L container and left outdoors. After 10 days, the fermentation status was observed. It was confirmed that the sample with a C / W ratio of 2.18 in experiment number 3 had progressed the most in decomposition and fermentation, with the volume reduced to about 1 / 10 of its original size (volume reduction rate). The reduced material still had a moist feel and was almost odorless. In contrast, volume reduction due to fermentation was confirmed in Experiment 2, where the C / W ratio was 2.00, but the volume reduction was less than in Experiment 3, with the bulk reduced to about 1 / 5, and the odor remained, although it had decreased.Furthermore, volume reduction hardly progressed in Experiment 1, where the C / W ratio was 1.50, and some of the material had a strong odor. On the other hand, in experiment number 4, where the C / W ratio was 2.50, volume reduction due to fermentation was observed, but only to about one-third, and the odor, although reduced, remained.Furthermore, in experiment number 5, where the C / W ratio was 3.00, some parts were decayed, and it is believed that the high moisture content in this sample promoted anaerobic fermentation rather than aerobic fermentation. Incidentally, when the temperature over time was measured for each experiment number, the temperature inside the mixture for experiments 2, 3, and 4 rose to 60-65°C after approximately two days, while the temperature for experiments 1 and 5 only rose to about 45°C.

[0013] <Experiment 2> organic wasteConcentrated sewage sludge generated in the process of treating sewage water was selected as the carrier, and cedar chips were selected as the carrier. Mixtures were created by mixing these materials, and by adjusting the mixing ratio, mixtures with C / W ratios of 2.90, 2.18, and 1.80 were obtained (Experiment Nos. 6, 7, and 8). Furthermore, water was added to the mixture of Experiment No. 6 to adjust the C / W ratio to 2.18 (Experiment No. 9), and weeds and waste oil (tempura oil) were added to the mixture of Experiment No. 8 to adjust the C / W ratio to 2.18 (Experiment Nos. 10 and 11). As in Experiment 1, 10 kg of each of these was placed in a 30 L container and left to stand, and the progress after standing was observed. The fermentation state was then observed in the same way after 10 days, and Experiments Nos. 6 and 7 showed the same results as in Experiment 1. fermentation The decomposition process was slow, resulting in little volume reduction and a strong odor remaining. However, in experiments 7, 9, 10, and 11, in which the C / W ratio was adjusted to 2.18, fermentation decomposition was promoted in all cases, and as in experiment 1, a volume reduction of about 1 / 10 was confirmed and the odor was almost completely eliminated. [Industrial Applicability]

[0014] The present invention relates to a method for treating activated sludge waste from treated sewage water, livestock excrement, etc. organic waste It can be used in the treatment method of

Claims

1. A method for treating organic waste, characterized in that when a mixture of organic waste selected from concentrated sewage sludge, food waste, shochu waste, bean-making waste, livestock manure, chicken droppings, and dehydrated blue-green algae sludge is decomposed by fermentation under aerobic conditions, with a carrier material being one or a mixture of weeds, cedar chips, rice bran, rice husks, and sawdust, which are plants that respond to soil disturbance, the mixture of organic waste and carrier material is adjusted so that the C / W ratio is in the range of 2.00 to 2.50, where C is the calorific value of the organic waste and W is the latent heat of vaporization of the organic waste.

2. 2. The method for treating organic waste according to claim 1, wherein the C / W ratio is adjusted to 2.

18.

3. 2. The method for treating organic waste according to claim 1, wherein the adjustment of the C / W ratio to the range of 2.00 to 2.50 is carried out by adding water when the C / W ratio is higher than the range, and by adding energy materials such as waste cooking oil, food waste, rice bran, or weeds that are plants that can cope with soil disturbance when the C / W ratio is lower than the range.