JPH02265700A - Recovery of calcium compound from putrefactive waste - Google Patents

Abstract

PURPOSE:To efficiently recover a calcium compound as a manuring effect component by a method wherein a specific amount of porous highly active quick lime is added to putrefactive waste composed of a solid-liquid mixture under stirring and the formed slurry is dried and burnt. CONSTITUTION:5-50 pts.wt. of a porous additive containing 95% or more of calcium oxide is added to and mixed with 100 pts.wt. of putrefactive waste composed of a solid-liquid mixture under stirring to be reacted with said waste while the formed slurry like substance is dried and burnt to recover a calcium compound and the heat accompanied by the aforementioned combustion is also recovered to be re-utilized. As an embodiment of the aforementioned calcium compound, there is a composition containing calcium phosphate and calcium carbonate. As an embodiment of the putrefactive waste, there is sawdust or one prepared by composting bark impregnated with excretion of a domestic animal.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for treating livestock manure, water/sewage surplus sludge and other putrescible wastes and recovering calcium compounds from the putrescible wastes. It is something.

(Prior art and its problems) Among putrescible wastes, for example, livestock manure from cows, pigs, chickens, etc. can be treated by impregnating sawdust or bark, and fermenting and composting this. I'm trying.

In addition, various treatment methods such as composting, landfilling, and combustion are used to treat surplus water and sewage sludge.

Furthermore, the current situation is that some putrescible industrial waste is simply solidified by adding slaked lime and the like, and then dumped as is in a designated location.

Therefore, when processing this type of waste, it is difficult to reuse it, and even if reuse is attempted, the processing cost is too high and it is impractical.Also, when it is composted and used, it does not decompose. Not only does this take a considerable amount of time, the foul odor during the process is extremely bad, and furthermore, microorganisms are likely to become nitrogen starved as they consume nitrogen.

The present invention aims to efficiently process such perishable waste in a short time and at low cost, and to recover calcium compounds from the perishable waste as a fertilizing ingredient. The purpose is to provide a collection method.

(Means for Solving the Problems) In order to achieve the above-mentioned objects, the present invention provides that the content of calcium oxide is 95% or more and the porous Add 5 to 50 parts by weight of an additive whose main component is highly active quicklime, mix and stir to react, dry the resulting slurry, and burn it to form a calcium compound. It is characterized by recovering and reusing the heat accompanying the combustion.

As the putrescible waste to which the present invention is applied, pig human waste (4
(including A), chicken manure and other livestock manure, animal blood, excess water and sewage sludge, and putrefactive residue discharged from food manufacturing factories such as shochu scum and okara scum. For example, in the case of pig human waste, it is usually 86.5% to 94.5%, in the case of dried chicken manure, it is usually 15 to 30%, in the case of excess water and sewage sludge, it is usually 75 to 97%, and in the case of food factories. In the case of perishable residue, it usually contains 75 to 95% moisture,
When used in the present invention, it is desirable that the moisture content be adjusted to 75 to 97%.

In the present invention, as shown in the attached block diagram, additives are added to these raw materials and mixed and stirred to first obtain a slurry-like substance. Specifically, 5 to 50 parts of the specified additive was added to 100 parts by weight of the above-mentioned putrescible industrial waste.
Add 1 part of fL and allow both to react.

The additive is mainly composed of highly active quicklime that meets the following conditions.

■High content of calcium oxide (preferably 95% or more) and low content of calcium hydroxide, calcium carbonate and other substances.

In addition, a small amount of magnesium oxide (for example, 5
% or less) may be included.

■Porous, with a large surface area and specific surface area, and a highly developed pore structure.

(2) When brought into contact with a small amount of water, for example, 1 to 2 g in about lθ to 15 ml of water, it has excellent water dispersibility, that is, it has the property of being dispersed fairly widely in all directions.

(2) When a medium amount is added to water, for example, 5 to 10 g to about 15 to 20 ml of water, a violent reaction occurs after a few seconds to generate water vapor.

(2) When a certain amount of water is added, for example, 20 g to 100 ml of water, a sufficient reaction occurs and a temperature rise close to the theoretical value is observed.

(2) In a slurry whose main component is slaked lime after contact with water, the sedimentation rate is low, for example, no sedimentation phenomenon is observed when the slurry is added at the rate described in (2) above and left for 15 minutes.

Among the above conditions ■ to ■, ■ to ■ are properties that can be inevitably derived from ■ and ■, and ■ is a condition for ultimately checking whether the conditions ■ to ■ are satisfied. It is.

If the reaction time of this highly active quicklime-based additive is too long, it will exhibit a kneading phenomenon (paste formation, fineness), and the resulting soil conditioner will be difficult to form agglomerated structures.
In addition, since it becomes difficult to dry, it is desirable that the drying time be within 15 minutes. However, if the raw materials contain substances that are difficult to react with, such as phospholipids, liquid oils, basic substances, and difficult-to-decompose polymer compounds, the reaction time may be extended as appropriate. It should be noted that if the additive contains 5% or less of magnesia, it will be more effective when the combustion residue, which will be described later, is used as fertilizer. In addition, when adding additives, instead of adding the additives in the above-mentioned weight percentage at once, divide the additives into multiple batches, first react with those that are easy to react, and then gradually react with those that are difficult to react with. It may also be made to react with things.

In the slurry-like substance obtained as a reaction product, about 97% of the water-soluble phosphoric acid contained in the organic waste is fixed as active calcium phosphate, and organic phosphoric acid, phospholipids, It contains calcium phosphate and fatty acid calcium produced by decomposing persistent components such as glyceride, and an organic substance in which calcium is dispersed.

Calcium phosphate in its active form is produced by the reaction of the above-mentioned additive with water-soluble phosphoric acid present in putrescible waste and phosphoric acid contained mainly in phospholipids. Therefore, the water-soluble phosphoric acid and lipids contained in the perishable waste, which is the raw material, are significantly reduced.

The slurry-like material thus produced is wetted, dried, and then combusted. For combustion, a small amount of combustion improver or combustible waste may be used.If poultry manure containing sawdust is used as the combustible waste, calcium such as calcium phosphate may be used as the residue after burning the poultry manure. Compounds can also be obtained effectively here.

In the combustion state, the above-mentioned organic compounds, which are the components of the substance, propagate and burn while emitting smoke, and the combustion residue contains calcium carbonate, calcium phosphate, calcium oxide, a small amount of calcium hydroxide, and a small amount of metal oxide. etc. are included. These residues are effective as fertilizer.

Further, the heat generated when the product is combusted may be used as a heat source for pre-drying the raw material slurry or the reaction product, or may be recovered as hot air or hot water via a heat exchanger. When used as a heat source for pre-drying reaction products, drying can be performed without being affected by weather, wind, temperature or season. Usually 5 is contained in the exhaust gas during combustion.
Contains ~12% carbon dioxide gas, and by reacting this exhaust gas with calcium hydroxide in the reaction product,
By promoting the production of calcium carbonate, the drying rate of the reaction product can be improved. It is also possible to utilize exhaust gas to promote plant growth in a similar manner.

(Example) Examples of the present invention will be shown below.

[Example 1] In this example and the next example, first, a process will be shown in which a predetermined additive is added to putrescible waste and a slurry-like substance is reacted and produced.

140 kg of an additive whose main component is quicklime with high activity is added to 850 kg of a slurry with a moisture content of 85.0% by weight, which is made of a mixture of chicken manure, sawdust, and pig excrement as raw materials.
(16.5% by weight based on the material) and reacted for 15 minutes with stirring in a special reactor.

In the above reaction process, the temperature of the reactant slurry rises due to the reaction heat generated by the hydration reaction and chemical reaction between quicklime and water, and the degree of temperature rise (difference between the reactant slurry temperature and the raw material slurry temperature) is 46 It was 0°C.

The obtained reactant slurry was air-dried in a roofed house (equipped with forced ventilation facilities) while being in contact with the atmosphere until the moisture content was 38.
．． 505 g of 0% by weight reaction product was obtained.

The water-soluble phosphoric acid content in the raw material is 11,200mg/g
(on a dry basis), whereas the component in the reaction product was 59 mg/g (on a dry basis).
The lipid content in the raw material was 39.200 mg/Kg (dry basis), whereas the content of the component in the reaction product was 5.220 rng/Kg (dry basis).

Therefore, the removal rate (reduction rate) of water-soluble phosphoric acid in this example from the above-mentioned putrescible waste corresponds to 99.5%, and the removal rate (reduction rate) of lipids corresponds to 86.7%.
The reactant is contained in the stainer as a calcium compound, among other things.

[Example 2] 96 kg (J!
;11.7% by weight based on the total amount) and reacted for 8 minutes with stirring in a special reactor.

In the above reaction process, the temperature of the reactant slurry rises due to the reaction heat generated by the hydration reaction and chemical reaction between quicklime and water, and the degree of temperature rise (difference between the reactant slurry temperature and the raw material slurry temperature) is 33 It was ℃.

The obtained reaction product slurry was air-dried in a roofed house while being in contact with the atmosphere to obtain 308 kg of a reaction product having a water content of 38.5% by weight.

Water-soluble phosphoric acid content in raw materials is 12,200mg/Kg
(on a dry basis), whereas the amount of the component in the reaction product was 27 mg/g (on a dry basis). In addition, the ammonia nitrogen content in the raw material is 34.2oor
ng/Kg (dry basis), whereas the component in the reaction product was 281 mg/kg (dry basis).
'standard).

Therefore, the removal rate (reduction rate) of water-soluble phosphoric acid in this example for the above-mentioned putrescible waste corresponds to 99.8%, and the removal rate (reduction rate) of ammonia nitrogen corresponds to 99.2%.
Such materials are included in the reactant slurry as calcium compounds and others.

[Example 3] Next, an example will be shown in which the reactant slurry obtained as in the above example is burned.

For combustion, dry chicken manure (moisture 15% to 30%, sawdust 40 to 60%) is used as fuel, and a small amount of waste oil is impregnated in advance as a combustion improver (approximately 2 to 3%), or a dead person or a small amount of By using flammable fuel, combustible components in dried chicken manure are burned. The combustion heat generated at this time can be used as a heat source for drying the wet reaction product (cake-like).

When drying the reaction product, a large amount of carbon dioxide gas (5 to 1
There are two methods: one is to bring the combustion exhaust containing 5%) into direct contact with the reaction product cake, and the other is to dry it using humidified air using an appropriate heat exchanger. The direct contact method is also advantageous because the slaked lime remaining in the reaction product cake reacts to form calcium carbonate.

As the reaction product cake continues to dry, its temperature increases, and it finally ignites and begins to burn slowly. This combustion state can be adjusted to a considerable extent by changing the amount of air.

Furthermore, it is of course possible to make effective use of the heat generated by this combustion by bringing it into contact with a new reaction product cake.

To the reaction product cake containing 45.0 to 53.0% moisture, 3% by weight of combustible waste oil was evenly added to dried chicken manure with a moisture content of 25.0%, and the mixture was heated on a metal net. After drying, the dry reaction product was subsequently combusted. The lipid content in the reaction product before combustion is 10,400 to 11,400 mg/
kg (dry basis), but the residue after combustion was 28
It decreased to 0 to 1.480 rrrg/kg (dry weight basis).

On the other hand, the total phosphoric acid in the reaction product is 2.43-2.75%
(dry basis), but in the residual soaking, combustible components are burned, so total phosphoric acid is 4.18 to 6.2
It is thought that phosphoric acid concentrated to 8% (light weight standard) remains as calcium phosphate, and other main components such as calcium carbonate coexist.

By such a method, it is possible to obtain a reaction product containing a relatively high content of calcium phosphate in calcium carbonate or a calcium compound.

Note that when the raw materials contain a large amount of total phosphoric acid, the amount of calcium phosphate in the reaction product obtained by the above method will naturally be high.

Next, an example of fertilization using a calcium compound as a combustion residue (hereinafter simply referred to as residue) obtained based on the above-described example will be shown.

[Example 4] This example shows an example in which a pot test was conducted in a greenhouse.

20 of the above residue per 1 Q 0m2 (17-Jl/)
0g was added to the soil and mixed with the soil so that it was almost uniform over a depth of about 12 cm. Note that a commercially available chemical fertilizer was added as a basic fertilizer.

On the other hand, for the control plot, a commercially available chemical fertilizer was added in the same proportion without adding any residue, and a comparative test was conducted.

A comparison of the residue-added plot and the control plot for the spinach crop is shown below.

1st crop (plant density 5 plants/1 bot, plastic No. 5 pot) Residue addition control control weight 87.3g 71.9g According to this example, it was possible to obtain a heavy crop in the first year. did it.

[Example 5] The residue obtained in the above example was added to 6 to 150 per Zoom 2 (1 are) of open ground, and mixed with soil so that it was almost uniform over a depth of about 100 cm. A commercially available chemical fertilizer was added as a basic fertilizer.

On the other hand, for the control plot, the above improvement materials were not added.
A comparative test was conducted by adding commercially available chemical fertilizers in the same proportions.

Long yam was used as the crop, and the following shows a comparison between the additive plot and the control plot.

First year reactant addition control control weight/wood 834g 502g quality (3L)
11% O% According to this example, the weight and
I was able to obtain long pieces of excellent quality.

[Example 6] The residue from the above example was added to 75 to 6 per 100 m2 (1 are) of open ground, and mixed with soil so that it was almost uniform over a depth of about 12 cm. A commercially available chemical fertilizer was added as a basic fertilizer.

On the other hand, for the control plot, a commercially available chemical fertilizer was added in the same proportion without adding any improvement material, and a comparative test was conducted.

Garlic was used as a crop, and the results of cultivating it divided into additive plots and control plots are shown below.

First year addition group Control group Bulb weight/plant 151.5g 130.0g Quality (2L bulbs/10 bulbs) 10 8 As is clear from this example, the addition group produces garlic that is superior in both weight and quality. was completed.

[Example 7] The residue according to the above example was applied to soil, house JOOm2 (1
6 per area) was added to 300 and mixed with soil to a depth of about 120 cm so that it was almost uniform, and a commercially available chemical fertilizer was added as a basic fertilizer.

On the other hand, for the control plot, a commercially available chemical fertilizer was added in the same proportion without adding any improvement material, and a comparative test was conducted.

A comparison of the added area and the control area for the burdock crop is shown below.

(First year) Addition area Control area Length 100-120cm Thickness 70-90cm
2-2. 5ca+ 1~1, 5cm Color tone White with light brown Brown freshness retention 30 days or more Within 15 days (2 years) Added area Control area Length 100~130c+s 60~90cm Thickness
2-2. 5CIII O18-1.5C11 Roots Many and long branches and roots Few and short branches and roots (fine roots) Color tone Light brownish white Brownish freshness retained More than 30 days Within 15 days According to this example, in the first year However, it can be seen that the addition of wood residue produced better results in the second year as well.

[Example 8] The residue obtained in Example 2 was added to 100 m2 (1
200 cents per R) was added and mixed with the soil so as to be almost uniform over a depth of about 25 CII+, and a commercially available chemical fertilizer was added as a basic fertilizer.

On the other hand, for the control plot, the above improvement materials were not added.
A comparative test was conducted by adding commercially available chemical fertilizers in the same proportions.

The results for the eggplant crop are shown below, comparing the reactant-added plot and the control plot.

(First year) Reactant addition area Control area Number of items (per harvest period) 320 items 120 items Harvest period
150 days 120 days (2 years) Reactant addition area Control area Number of pieces (per harvest period) 350 pieces 130 pieces Harvest period
155 days 125 According to the Japanese example, it can be seen that this residual pickling has an effective effect on the growth of crops in the second year as well as in Example 7.

(Effects of the Invention) As described above, according to the present invention, a predetermined additive containing highly active quicklime as a main component is added to solid-liquid mixed putrescible waste, and the resulting slurry is reacted. By burning the material, most of the total phosphoric acid contained in the putrescible waste is stabilized as active calcium phosphate, and water-soluble phosphoric acid is reduced to less than 3% of its original amount. , perishable waste can be efficiently processed at low cost without causing pests, harmful microorganisms, etc. due to unreacted residues, or producing bad odors.

Furthermore, according to the present invention, since the reaction slurry is combusted, only the calcium compound that is effective as a fertilizer component can be recovered from the putrescible waste.When viewed as a fertilizer, Yuko's calcium compound is slow-acting, slow-acting,
It has excellent hydrophobicity and water absorption, and is long lasting.

Furthermore, according to the present invention, the heat generated when burning the reaction slurry can be reused as a heat source for drying the reaction slurry, etc.
This has the advantage that heat can be used effectively.

[Brief explanation of drawings]

The figure is a block diagram showing the steps of the method of the invention.

Claims (8)

[Claims] (1) For 100 parts by weight of solid-liquid mixed putrescible waste,
Add 5 to 50 parts by weight of a highly active quicklime-based additive with a calcium oxide content of 95% or more and porosity, mix and stir to react, and create a slurry. A method for recovering calcium compounds from putrescible waste, comprising recovering calcium compounds by drying a substance and then burning it, while recovering and reusing the heat accompanying the combustion. (2), wherein the calcium compound contains calcium phosphate and calcium carbonate;
A method for recovering calcium compounds from putrescible waste according to claim 1. (3) The perishable waste is sawdust, bark impregnated with livestock human waste and composted, or in the process of fermentation.
Method for recovering calcium compounds from putrescible waste as described in Section 1. (4) The additive has excellent water dispersion properties, instantaneous reaction properties with water, and temperature increase properties close to theoretical values upon reaction with water. The method for recovering calcium compounds from putrescible waste according to item 1. (5) The method for recovering calcium compounds from putrescible waste as set forth in claim 1, wherein the additive contains 5% or less of magnesia. (6) In the combustion process according to claim 1, sensible heat and steam latent heat in the combustion exhaust are used to preheat the perishable waste before mixing the additive, and carbon dioxide in the combustion exhaust is used. A method for recovering calcium compounds from putrescible waste, characterized in that gas is used to promote plant growth. (7) A method for recovering calcium compounds from putrescible waste, characterized in that in the combustion process according to claim 1, combustion exhaust gas is used to dry reactants before combustion. (8) In the combustion process described in claim 1, hot water or hot air is obtained from the combustion exhaust through a heat exchanger. Collection method.