The present invention relates to a novel method for treating organic wastes, and more specifically relates to a method for producing a feed by using organic wastes and oils as the raw materials to form a koji-fermented feed.
Additionally, the present invention relates to a method for treating highly concentrated organic wastes with a BOD of at least 10,000 ppm such as sake lees and food scraps, and further relates to a crude fiber feed comprising a ligneous matrix obtained by treatment with the above-described treatment method.
In recent years, the problem of how to treat waste from the food processing industry or highly concentrated organic waste such as food scraps has become one which has bearings on the public health. This is because they contain large amounts of water and are perishable, generating malodorous fumes in the process. While this type of waste is usually simply discarded, the burial of these substances results in their decay in the soil, producing large amounts of nitrate-nitrogen which can contaminate ground water. Additionally, if incinerated, they can generate dioxins and NOX, which can pollute the atmosphere. Moreover, the amount of such organic waste is increasing annually at an alarming pace.
Therefore, many methods of fermenting organic waste to make fertilizer or methods for treating waste for decomposition in order to enable larger amounts of waste to be collected and recycled have been proposed in recent years, but with conventional methods, the treatments can take months, and their utility has been limited due to the risk of saline pollution when used in large amounts because of the salt content in the resulting fertilizers. Furthermore, such waste often has a high water content, making storage and transport difficult. As a result, this type of waste has not been able to be used effectively.
On the other hand, there are methods for making such raw garbage into fertilizer using microbes, but such microbes are not very compatible with garbage having a high oil content, so that there are limits to the range of raw waste that can be treated in this manner.
The present invention has been made in consideration of the above-described circumstances, and has a first object of offering a novel means for making effective use of the above-described organic wastes.
The present invention has the further object of offering a method for producing a feed by efficiently processing the above-described organic wastes.
The present invention also has the object of offering a feed produced by the above method.
The second object of the present invention is to offer a method for treating organic wastes such as sake lees and food scraps, especially highly concentrated organic wastes with a BOD of at least 10,000 ppm, with extreme efficiency in a short period of time.
Another object of the present invention is to offer a method for treating an organic waste capable of converting a large amount of waste into a readily disposable form, and use of a substances treated in this way.
As a result of diligent research towards achieving these objects, the present applicant discovered that if oils are added when treating organic waste with certain molds, the molds can transform the oils into fuel and efficiently convert them into the heat of fermentation. That is, they found that by employing oils as energy sources for the molds to dramatically improve the decomposition and drying speed of the organic matter due to the mold, it is possible to efficiently treat organic wastes. Additionally, more surprisingly, they discovered that when ammonia gas and acetic acid are generated, the generation thereof can be prevented by mixing in some oils, that is, the addition of oils can inhibit the proliferation of putrefying bacteria such as acetic bacteria.
The present invention offers a method for treating organic wastes, comprising steps of mixing said organic wastes with a mold to obtain a mixture, and allowing said mixture to ferment and dry, wherein the oil content of said mixture is at least 2 wt %, preferably at least 5 wt %, more preferably at least 10 wt % with respect to the water content of said mixture. In this way, the heat of fermentation of the mold can be used to efficiently dry the wastes.
According to a first object of the present invention, a feed is produced by adjusting the oil content of a mixture of organic wastes and koji mold or koji to at least 3 wt %, preferably at least 5 wt %, more preferably at least 10 wt %, and allowing said mixture to ferment and dry. Preferably, the feed is produced by mixing together organic wastes, oils, koji mold or koji, and allowing the koji mold to ferment and dry the waste.
By adding oils as nutrients in this way, the processing speed of organic wastes, in particular highly concentrated organic wastes can be highly improved.
Furthermore, according to this type of method, raw garbage, livestock excrement and the like which has conventionally been discarded can be effectively used.
Furthermore, since the method of the present invention makes use of koji mold instead of treatments using high temperature microbes, so that while a portion of the organic matter is decomposed into carbon dioxide and water, the most part is synthesized into microbial proteins, while large amounts of digestive enzymes are secreted for digestive consumption. As a result, a feed of high nutritional value which is suitable for feeding to livestock and the like is obtained. That is, while the treatment of organic waste by microbes has conventionally been for the purpose of breaking down wastes, the method according to the present invention enables the generation of active ingredients by the koji mold, thereby changing the organic waste into feed which can then be put to effective use.
In the present invention, oils are used in order to produce a feed fermented by koji mold from organic wastes. Conventionally, the fermentation and heat generation due to koji mold has been mainly used for decomposition of starches, but in the present invention, the oils are used to assist largely in the fermentation and heat generation. Since the koji mold can consume the oils and efficiently convert them to the heat of fermentation, there is no particular need to add nutrients for growth of the koji mold, and the oils act as an energy source to dramatically increase the speed of decomposition and drying of the wastes. Therefore, there is no need to specially add starchy materials even to wastes such as raw garbage with a low starch equivalent. Furthermore, since there are few microbes that can consume oils in nature, the koji mold, which is relatively susceptible to contamination with other microbes, can be grown with dominance. The adjustment of the oil content should preferably be done by intermixing oils, the amount of oils normally added being preferably at least 1.5 wt %, more preferably at least 5 wt %, and most preferably at least 10 wt % of the water content of the mixed organic waste.
The oils used in the present invention can be of any type as long as they are able to achieve the object of the present invention, and can be chosen from among animal, vegetable or mineral oils, or combinations thereof. Some examples are those which are readily available, including edible oils such as frying oil, lard, soy oil, waste oil from meat processing or olive oil, or cutting oils, with those having a boiling point of at least 100xc2x0 C. being most preferable. When preparing a feed, edible oils are preferable.
Additionally, the mold in the present invention refers to filamentous eukaryotic microbes (molds), particularly Aspergillus, Monascus, Mucor and Rhizopus, of which Aspergillus and/or Monascus are chosen with preference for having amylase and lipase activity, further among which Aspergillus oryzze kawachii and Aspergillus awamori kawachii (available from Kirishima Kogen Beer KK) have a high oil-decomposing ability and can be used effectively. Normally, oils are avoided due to the inability of conventional fertilizer plants to process them. However, by using this type of koji mold, which has a high oil decomposing ability, a waste with a high oil content can be effectively treated. Additionally, they can be used in combination with other molds which can suitably assist in the decomposition process.
According to a second object of the present invention, an organic waste and oils are preferably added to a matrix material to form a mixture, and a mold is grown in the mixture to treat the organic waste by fermentation thereof.
In this case, the organic waste should preferably be provided in an amount such that the water content is 20-70 wt %, preferably 20-40 wt % with respect to the matrix material.
Additionally, the matrix material used in the treatment method of the present invention can be of any type as long as it is capable of achieving the object of the present invention, but should preferably be a pulverized ligneous material. For example, sawdust, wood shavings, and their mixtures are suitable for use.
Additionally, the mold can be allowed to occur naturally in the mixture, or positively added to the mixture. The amount added should be in the range of about 0.01% to 0.1% of the total dry weight of the mixture.
According to the present invention, the treatment process is usually a continuous process such that as the organic waste is being treated, new batches of the organic waste and oils can be added as needed. Here, the matrix material can also be supplemented if necessary.
In the processing method according to the present invention, the mixture is preferably adjusted to 50xc2x0 C. or less, preferably about 40-50xc2x0 C. This temperature regulation should preferably be performed by ventilation, and it is especially convenient to blow warm dry air which is available from the exhaust heat from the generator of the ventilator.
Additionally, once the koji mold begins to grow and fermentation begins, the heat of fermentation causes the waste to dry so as to result in a feed with a water content below a desired level, and this can be improved by making proper adjustments to the speed and level of drying due to the ventilation of warm air. The final water content of the feed should preferably be about 30 wt % or less, preferably 20 wt % or less, and most preferably about 15 wt % or less.
Furthermore, in the present invention, a feed obtained by the above-described processing method is offered. This feed has an extremely high nutritional value, and is suitable for feeding to livestock such as cattle, swine and fowl. Furthermore, when using a matrix material, a matrix material obtained by treating organic waste can be used as a crude fibrous feed. Since the koji mold uses oils as an energy source, the oils are consumed and reduced. Moreover, the feed will contain lipases from the koji mold. While oils can cause diarrhea in livestock, this problem can be completely overcome due to the presence of lipases, so that the oils can actually be used to raise the nutritional value of the feed and promote the growth of the livestock. Furthermore, the action of the koji mold also leaves large amounts of other enzymes such as amylase, protease and active oxygen-decomposing enzymes in the feed, which can then largely assist in digestion by livestock to which the feed has been fed, thereby relieving stress. Additionally, it also has the effect of suppressing the foul odor of livestock excrement.
Furthermore, while livestock fed feeds containing unsaturated fatty acids can have reduced meat quality due to yellowing or the like, treatment with koji mold reduces the amount of unsaturated fatty acids, thus giving the livestock fed the feed of the present invention good meat quality.