JPS638286A - Fermentation dry method for organic sludge - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention Industrial Field of Application The present invention relates to a method for fermenting and further drying organic sludge.

Conventional techniques and their problems Conventionally, it has been considered most desirable to ferment organic sludge and compost it.

However, sludge has a very high moisture content of 50-90% and is viscous, so it has poor ventilation and requires a lot of time for fermentation and drying. Fermented compost also has poor ventilation and is difficult to dry, so it is packed in bags. It was very difficult to dry it to the point where it could be done.

The present invention has been made to solve the above problems,
To provide a fermentation-drying method for organic sludge that can efficiently compost organic sludge and then efficiently dry it to easily obtain compost ready for bagging.

Structure of the Invention The structure of the present invention is to mix zeolite in an amount of at least 40% based on the solid content of organic sludge, to promote fermentation by the air permeability of the zeolite while supplying air and stirring the mixture, and then to The gist of the present invention is a method for fermentation and drying of organic sludge, characterized in that after the fermentation, the zeolite is mixed while maintaining its air permeability and dried by hot air and stirring.

Means to Solve the Problems Noting that zeolite has excellent air permeability, they considered mixing it with organic sludge and fermenting and drying it.

The zeolite used in the present invention is abundantly produced in Japan, and attempts have been made to use it for moisture adjustment when making compost. However, if the purpose is only for moisture adjustment, the amount of zeolite mixed should be This meant that a large number of products had to be produced, resulting in high costs and unprofitability.

However, it has been found that when this zeolite is mixed for the purpose of using it as an aeration material, the amount added can be about half or less compared to the case of water adjustment.

That is, if the amount of zeolite mixed in the present invention is at least 40% or more based on the solid content of organic sludge, the purpose of promoting fermentation and drying can be achieved.

In addition, if the mixing ratio of the second zeolite is less than 40% based on the solid content of the organic sludge, the effect as an aeration material will be extremely reduced, and the object of the present invention will not be achieved.

The reason for this cannot be clearly elucidated, but it is probably because zeolite has excellent water absorption properties that 40%
If the amount is less than 20%, most of the water will be absorbed within the porous layer of the zeolite as a ventilation material, or the water will be adsorbed on the surface, resulting in a significant decrease in air permeability.

The preferred range of the mixing amount of this zeolite is 50 to 200% based on the solid content of organic sludge, and even if it is mixed in more than 200%, the effect will not improve, and adding more than 200% will be wasteful. If even % of sludge is mixed, the sludge concentration will drop significantly, and on the contrary, fermentation will be hindered.

In this way, the solid content ratio of organic sludge with a water content of 50 to 90% is at least 40% or more, preferably 50 to 20%.
0% zeolite is mixed and fermentation is carried out while supplying air and stirring. For example, if the total amount of the mixture is 500 kg, the appropriate amount of air supply is about 80 to 120 sentences/minute; if it is too little, fermentation will be hindered, and on the other hand, if there is too much supply air, it will be difficult to raise the fermentation temperature. This is not desirable in terms of fermentation.

Normally, the maximum temperature for this fermentation is 60-70'C.
Therefore, the fermentation conditions are 50 to 60'C on average, and very efficient fermentation can be carried out by appropriately mixing zeolite as an aeration material.

Regarding stirring, during this fermentation, it is best to use as little as 1 to 5.
It is sufficient to do this about once a day, and it may be done mechanically using a stirrer or manually using a shovel or the like.

When fermentation is carried out as described above, fermentation is usually completed in about 10 to 16 days and composting is achieved.

The sludge compost thus obtained is dried, but in this case, it enters the drying process while still containing the mixed zeolite.

This drying step may be carried out continuously in the same tank in which the fermentation was carried out, or may be carried out after being transferred to another drying tank.

This drying is carried out using warm air and stirring, and the preferable amount of hot air is 4 to 6 times that of the above-mentioned fermentation.
For example, for a total amount of 500 kg of compost, 350 to 6
It is sufficient to send hot air at 00M/min, and the temperature of the hot air is preferably 50 to 901C, but if it is warm air that utilizes the fermentation heat from the fermentation mentioned above, the temperature is 40M/min.
~7Q'C, and the purpose can be fully achieved even at this temperature.

Note that stirring during this drying process is usually desirably carried out 5 to 7 times a day, which is higher than during the above-mentioned fermentation, and it is preferable to use mechanical stirring.

The sludge compost after fermentation in the method of the present invention contains 40% or more, preferably 50 to 200%, of zeolite in terms of solid content, so if this is dried as it is, the action of zeolite as an aeration material will work greatly. Therefore, very efficient drying can be achieved.

As mentioned above, this zeolite also has excellent water absorption, so during drying, both water absorption and air permeability work together to produce a synergistic effect.

In other words, when the temperature of the mixed zeolite rises, the absorbed or adsorbed water will be released as water vapor from its porous pores and surface, and the water vapor will be easily discharged out of the mixture due to the air permeability of the zeolite. As a result, extremely efficient drying is achieved.

The time required for this drying varies depending on the conditions, but it is 1/2 to 1/3 of the fermentation days mentioned above. For example, for sludge compost with a moisture content of 60%, the moisture content usually decreases in 3 to 5 days. It dries to 15-20%.

Dried compost with a moisture content of 15 to 20% can be packaged as is, or all or part of this dried compost can be mixed into organic sludge before fermentation to adjust the moisture content of the sludge. It can also be used for.

The zeolite mixed in the present invention has a particle size of 0.
．． 5 to 21111 is preferable, and when zeolite with this particle size is contained in composted sludge, it adsorbs ammonia and reduces the generation of bad odors.This zeolite also has a high base substitution capacity and is useful for soil improvement. It is also excellent as a material, and if the dried compost obtained by the present invention is spread on rice fields, other cultivated land, and plant cultivation areas, the fertilizer retention capacity will be improved and the effects of the compost will be enriched, and it will exhibit extremely excellent agricultural effects. That's what I do.

Example For organic sludge, zeolite with an average particle size of 1 mm was added,
Mix each compounding ratio as shown in Table 1 below, adjust the total amount after mixing with zeolite to 150 kg each, and adjust the moisture content to 60%, air volume 30 sentences/min, once a day from the 18th fermentation. Fermentation was carried out under the same conditions of stirring and 11EI, and then these were transferred as they were to a drying tank, and heated with 70"C hot air at 150 v/min, 191! stirring 5 times a day, for 5 days. It was dried under the same conditions.

These results are shown in Tables 1 and 2.

Table 1 (Fermentation) This table shows that when the mixing ratio of zeolite is less than 40%, the fermentation ability is greatly reduced, when it is 50 to 200%, it is almost the same favorable state, and when it is 400%, the fermentability is decreased. This is recognized.

Table 2 (dried as is from Table 1) From this table, sludge compost that does not contain zeolite dries extremely poorly and cannot be packaged, and the zeolite content is less than 40%. However, if the zeolite content is increased to 50 to 200%, the dry compost can be packed into bags.
It is judged that very efficient drying is being carried out. Also, the reason why the drying efficiency slightly decreased when the zeolite mixing ratio was very high (400%) is thought to be because the drying temperature did not rise because the fermentation temperature was low due to the small amount of organic matter. It is.

C. Effects of the Invention The present invention is as described above, and its effects are enumerated as follows.

(a) Fermentation of organic sludge can be achieved very efficiently by adding zeolite as an aeration agent at a relatively low mixing rate.

(b) By drying the sludge compost after fermentation that still contains this zeolite, this zeolite exhibits water absorption, air permeability, water vapor release, etc., and these act synergistically to achieve extremely high efficiency. drying will be performed.

(C) The moisture content of the sludge compost obtained by this drying has decreased to 15-20%, compared to conventional sludge compost that could only reduce the moisture content to 35-45%. It can be said to be a very good dry compost, it can be easily packaged in bags, and it can also be used to adjust the moisture content of raw sludge.

(d) Furthermore, since zeolite is mixed in the dry compost obtained by the present invention, it also has the effect of adsorbing malodorous components such as ammonia and making it difficult to release malodors.

(e) Furthermore, this zeolite has good fertilizer retention ability and is excellent as a soil improvement material, enriching the effects of composting and making it extremely effective for business closure.

As described above, the method of the present invention exhibits various remarkable effects,
It is extremely useful for fermentation and drying of organic sludge and for business management.

Claims (1)

[Scope of Claims] 1. Mix at least 40% or more of zeolite with respect to the solid content of organic sludge, supply air and stir to this mixture to promote fermentation due to the air permeability of the zeolite, and then A method for fermentation and drying of organic sludge, characterized in that after fermentation, the zeolite is mixed while maintaining its air permeability and dried by hot air and stirring.