KR101144777B1 - Manufacturing method of soil modifier using sludge of dredge - Google Patents

Abstract

The present invention relates to a method for manufacturing a soil improver using dredged sludge. When washing or classifying excavated soil or dredged soil generated at the excavation of a river, lake, or tunnel, waste, sand, gravel, etc. are classified and mixed in dredged soil. The sludge, such as sediment, is suspended in the wash water and the wash water turns into a suspension. The sludge suspended in the wash water can be recycled by coagulation and sedimentation. At this time, coagulation and precipitation of sludge in the wash water with eco-friendly natural polymer flocculant dissolved chitosan in wood vinegar, dehydrated sludge with dehydrator, and dried to dryness to 30% or less in the dry phase and then calcium sulfate or calcium phosphate, calcium sulfate and Humic acid, minerals, bentonite, zeolite is mixed with a mixture of calcium phosphate is prepared by mixing the dried sludge with a soil improver. Soil modifiers manufactured in this way used environmentally friendly natural polymer flocculant instead of synthetic polymer flocculant, and thus caused environmental pollution and adverse effect on soil in the long term. It is an economical method that eliminates urea and prevents contamination of soil and coastal areas due to landfilling or ocean dumping by dredging sludge, land dumping sludge, and soil recycling. Is to present a way

Dredge sludge, natural polymer, wood vinegar, calcium sulfate, calcium phosphate, mineral, bentonite, zeolite

Description

Manufacturing method of soil improver using dredged sludge {MANUFACTURING METHOD OF SOIL MODIFIER USING SLUDGE OF DREDGE}

The present invention relates to a method for producing a soil improver using dredging sludge, and more specifically, to an environmentally friendly natural polymer flocculant in the step of coagulating and settling sludge in washing water in order to remove environmental contaminants in a conventional dredging sludge treatment method. After dewatering and drying the coagulated precipitated sludge, an additive prepared by mixing mineral sulfate, humic acid, bentonite and zeolite to a mixture of calcium sulfate or calcium phosphate, calcium sulfate and calcium phosphate is mixed with dry sludge as a soil improving agent. Manufactured and used as land and soil in paddy fields, fields, landscaping, and reclaimed lands to prevent soil and coastal pollution due to landfill disposal of dredged sludge or dumping at sea, and to improve acidified soil and plant growth by recycling dredged sludge. It is about producing useful resources.

In general, dredged soil is dredged, including dead sludge of microorganisms that lived in rivers or lakes, wastes from outside, sediment from sediments settled, and the dredging is first sorted by vibrating screen, which is a sorting equipment, drum screen and cyclone. The scrubber sorts and sorts the sand and gravel from which the soil particles and sediments that have adhered to the surface by the wash water have been cleaned. On the other hand, the fine water particles, sediments, sludge, etc. are suspended in the wash water, so the flocculant is precipitated and sludged by adding flocculant to recycle the wash water. It is either landfilled in landfills as cakes or dumped at sea. At this time, the flocculant used is a polymer which is a synthetic polymer flocculant. After aggregation, monomers inevitably exist and leak into the soil as low molecular weight substances or monomers even if they are degraded in the natural state. These monomers leak into the amide and aggregate the soil, impede the penetration of air into the soil, and make the soil anaerobic, causing the plant to have gas disturbances due to the growth of bad microorganisms and the generation of gas by the respiration of anaerobic microorganisms. It is reported that if the residue of acrylamide, which is highly toxic, is absorbed by plants and delivered to humans, it may cause paralysis or cancer of the central nervous system. On the other hand, in order to solve the problem of environmental pollution caused by the flocculant, a small amount of dredging sludge is not dehydrated but placed in a wide sedimentation tank to naturally settle the sludge. Although it is used as a soil improving agent by adding additives necessary for soil improvement, this method requires a large settling tank for sedimentation of sludge, which requires a large site, and it is difficult to dry during the rainy or rainy season. In addition, a technique used for agglomeration of waste activated sludge by mixing anionic chitosan-based polymers and cationic acrylic acid-based polymers as a flocculant is disclosed in Korean Patent Registration No. 10-0546484, but it is concluded that it is not environmentally friendly by using acrylic acid. .

A method for treating stone sludge using chitosan and chitosan degrading enzyme and a method for preparing fertilizer using the same are disclosed in Korean Patent Registration No. 10-0880990, but this method uses an aqueous chitosan solution, which is not specified, as a flocculant, Chitosan is used to fertilize stone sludge using chitosan degrading enzyme to convert chitosan into chitooligosaccharide and to nourish the plant, but it is expected to improve acidic soil or to omit the trace elements required by the plant. It can be hard to be.

The object of the present invention for solving the problems as described above,

We present the eco-friendly coagulation sedimentation method of dredged sludge which has no residual effect on the soil by coagulating and precipitating sludge by using eco-friendly natural polymer coagulant dissolved chitosan in wood vinegar solution.

After the precipitated sludge is dehydrated and dried, a mixture of calcium sulfate or calcium phosphate, calcium sulfate and calcium phosphate is mixed with additives prepared by mixing humic acid, minerals, bentonite, and zeolite, and then prepared as a soil improving agent. By suggesting how to use land or cover material in land, reclaimed land, etc.

While neutralizing the fundamentally acidified soil and continuously supplying minerals and nutrients necessary for plant growth, it also has the effect of disinfecting harmful microorganisms in the soil with wood vinegar, while also restraining the construction of additional landfill sites to bury dredging sludge in landfills. Its purpose is to prevent marine pollution caused by dumping sludge's ocean dumping.

Soil improving method using a dredging sludge of the present invention for achieving the above object,

Maturing the wood vinegar for at least 3 days; Separating the upper part containing volatile components, the middle part containing natural acetic acid components, the lower part containing tar and pitch in the aged wood vinegar solution; After the chitosan powder is added to the separated vinegar liquor, an eco-friendly natural polymer flocculant having a molecular weight of 1,600,000 to 2,000,000 (Mw) is prepared by dissolving the chitosan powder in the acetic acid component of the wood vinegar solution.

Washing the dredged soil with the natural polymer flocculant prepared above, separating sand and gravel, and then adding the sludge to the sludge by coagulating and precipitating the suspended solids contained in the wash water to a concentration of 0.01 to 3% by weight; Dewatering and drying the flocculated dredged sludge to cake to a water content of 30% by weight or less; Preparing an additive by mixing humic acid, minerals, bentonite, and zeolite with a mixture of calcium sulfate or calcium phosphate, a mixture of calcium sulfate and calcium phosphate; The additive is prepared by mixing with the dredged sludge of the cake state to produce a soil improving agent

Soil improver prepared in this way is sprayed about 1-3 ton per 1,000 m ² to paddy fields, fields, reclaimed land, landscaping land, etc., so that the pH of soil is maintained at 6.5 ~ 7.5 by additives included in soil improver. It has a large grain structure that improves the development of plant roots, improves air permeability in the soil and eliminates anaerobic bacteria in the soil, thus eliminating gas emissions from metabolic processes of anaerobic bacteria. It can also be used for land cover of farmland and reclaimed land or for landscaping in urban areas, and it is possible to recycle dredged sludge landfilled or dumped at sea.

In the manufacturing step of the natural polymer flocculant, it is preferable to add 400 to 600 g of dried chitosan per 1 L of the wood vinegar solution in the middle portion, and then stir for 12 hours or more to prepare the chitosan sufficiently dissolved and dissociated by the acetate component in the wood vinegar solution.

In preparing the additive, 1 ton of natural calcium sulfate, 1 ton of calcium phosphate, or 1 ton of a mixture of 500 kg of the two substances by weight ratio 0.5 to 1 L of mineral, 1 to 20 kg of humic acid, 10 to 50 kg of bentonite, 10 zeolite 10 It is preferable to prepare by mixing from 50kg

In the step of producing the soil improver, it is preferable to add the prepared additive to the dredging sludge cake dehydrated to less than 30% by adding 1 to 5% by weight in a weight ratio of the dredging sludge cake to be sufficiently mixed by a mixer.

Here, the "mineral" used in the present invention is usually in the liquid state of the ion solution extracted with lactic acid from minerals, calcium, potassium, magnesium, iron, zinc, selenium (selenium), manganese, silicon, lithium, germanium, boron, etc. Containing, the mineral solution used in the present invention is Ca, K, Mg, Fe, Zn, Se, Mn, Si, Li, Ge, B is 50, 300, 300, 500, 600, 20, 150, 20 , 200, 20, 100ppm or more.

The present invention as described above, using an environmentally friendly natural polymer flocculant from the process of flocculating the solids contained in the wash water and adding the additives capable of improving the soil to the dredged sludge dehydrated precipitated sludge produced as a soil improver paddy, field It is also used for landscaping and covering soils in landscaping and reclaimed lands to prevent environmental pollution from dredging sludge landfills or dumping at sea, and to reduce economic losses due to the construction of additional landfills.

The present invention will be described in detail through the following examples. However, these examples are for illustrative purposes only and the present invention is not limited thereto.

Example 1

According to an aspect of the present invention,

10L of commercially available wood vinegar (true charcoal wood vinegar) is aged in a closed tank for 5 days to separate layers, and then 1L of middle layer wood vinegar is added. 500 g of dried chitosan is added and stirred at room temperature for 12 hours to completely dissolve chitosan. Eco-friendly natural polymer flocculant was prepared

In order to examine the cohesiveness of the eco-friendly natural polymer coagulant according to the present invention, the coagulation characteristics according to the concentration of the natural polymer coagulant were examined as follows.

<Suspension setting of washing water>

When the washed water collected from the dredged soil washing site was examined, the particle size of solids in the wash water was 1-24㎛ and the average particle size was 3-5㎛, and the solid content was 330g in 10L of wash water.

<Cohesiveness Experiment with Coagulant>

A natural polymer flocculant prepared by dissolving 500 g of dry chitosan per 1 L of wood vinegar was prepared in an aqueous solution of 0.01% by weight, 0.05% by weight, 1.0% by weight, 2.0% by weight, and 3.0% by weight in a flocculant weight ratio, and then had an inner diameter of 26 mm and a length of 250 mm. Put 100ml of washing water collected from the field into 150ml glass settling tube, add the prepared aqueous solution, shake the light tube vigorously 20 times or more and settle the dredging sludge within 1 minute The results of observing the results are shown in Table 1.

<Table 1.>

In the above experiment, when the amount of the aqueous solution of natural polymer flocculant was added to the wash water was 0.1 wt% or more, most of the cohesiveness was very good. Therefore, the amount of the natural polymer flocculant solution was 0.1% by weight.

Example 2.

Effects of dredging sludge according to the present invention on the soil environment and the growth and yield of lettuce were examined.

Preparation of the soil improver according to the present invention by dehydrating the dredging sludge flocculated and flocculated with a flocculant aqueous solution made using 0.1% by weight of the natural polymer flocculant prepared in the above to dry the dredging sludge cake 20% of the moisture content around 30%; An additive prepared by mixing 10 ml of calcium sulfate, 10 ml of mineral, 0.1 kg of humic acid, 0.3 kg of bentonite, and 0.3 kg of zeolite; 400g was prepared by mixing well.

Four test zones were prepared with one area of 5㎡, and the fertilizers were fertilized in each test zone in the ratio of 1,000 to 4,000kg / 1,000㎡. Table 2 is as follows.

<Table 2.>

On the other hand, as a result of analyzing the physical changes of the soils of each test zone, the porosity of the test plots applied with the soil modifier increased significantly, indicating that the soil modifier makes the granules of the granules in the soil indirectly. A comparison table of soil physical properties as indirect evidence that they can grow well is shown in Table 3.

<Table 3> Comparison of Soil Physical Properties Before and After Application by Soil Modifier Treatment

In addition, as a result of comparing the amount of biomass C before and after using the soil improver, the test area using the soil improver increased the growth effect of the soil microorganisms. The more the amount of the soil improver used, the better the soil improver using dredged sludge. It may be used up. The results of this experiment are shown in Table 4.

<Table 4> Comparison of Biomass C content of total microbial biomass before and after application by soil treatment

After the soil modifier was observed, the soil pH was 6.64 before the soil modifier was added, but after the soil modifier was applied, the pH was increased from 6.81 to 6.97 to neutralize the soil, and the EC was 0.89 before the soil modifier was applied. Was changed from 0.45 to 0.28 and the soil quality was greatly improved. The experimental results are shown in Table 5.

＜ Table 5 ＞ Comparison of soil chemistry before and after application by soil treatment

As a result of testing the effect of soil modifier on production yield, the biomass and dryness of water quality were more than 5% in soil modifier treatment, showing the effect of using soil modifier. Compared with the results, the water yield increase effect of 148% or more is shown in Table 6.

<Table 6> Effect of Soil Enhancer Treatment on Growth and Yield of Lettuce

The plant used in the experiment was lettuce (variety: Cheongha Cheongchima lettuce: Asia seedling Co., Ltd.) and the soil improver was tested by planting lettuce seeds after spraying at the rate set in each test zone 5 days before the formulation. The result of measuring lettuce growth is shown in FIGS. 4 and 5.

According to the results of the experiment, when the soil improver using dredged sludge of the present invention is used as a land repellent or a soil cover agent, calcium, phosphorus, sulfur, minerals, humic acid, bentonite, zeolite, etc. contained in some organic substances and additives contained in the soil improver It is thought to help the growth, so I think that it is a good way to recycle dredging sludge.

Figure 1 is a photopolymer coagulant prepared by dissolving chitosan in the wood vinegar according to the present invention

2 is a picture of dredged soil washing water

Figure 3 is a photograph of the precipitated solid precipitate of the washing water with the polymer flocculant according to the present invention

Figure 4 is a photograph of measuring lettuce growth for each test using the soil improver according to the present invention

Figure 5 is a photograph comparing the lettuce growth status for each test using the soil improver according to the present invention

Claims (5)

In the soil improving agent manufacturing method, Aging wood vinegar to extract the middle vinegar solution, chitosan was added, stirring and dissolving to prepare a natural polymer flocculant; A step of coagulating sedimentation of solids in the dredged soil washing water with the natural polymer flocculant to form a precipitate: Dehydrating and drying the precipitate to prepare a dredge sludge cake; Preparing an additive by mixing minerals, humic acid, bentonite, and zeolite by selecting one of calcium sulfate or calcium phosphate, a mixture of calcium sulfate and calcium phosphate; Mixing the additive with the dredge sludge cake to prepare a soil improving agent; Method for producing a soil improver using a dredging sludge having. The method of claim 1, In the natural polymer flocculant manufacturing process, A method for producing a soil improver using dredging sludge, characterized in that for dissolving 300 to 600 g of powdered chitosan per 1 L of middle-aged wood vinegar extracted by aging for three days or more. The method of claim 1, In the flocculation precipitation step, Method for producing a soil improver using dredging sludge, characterized in that the natural polymer flocculant is added in a weight ratio of 0.01 to 3% per ton of dredged soil washing water. The method of claim 1, In the additive manufacturing step, One ton of calcium sulfate or only one ton of calcium phosphate, one ton of a mixture of calcium sulfate and calcium phosphate, each selected by 500 tonnes of minerals 0.5 to 1 L, humic acid 1 to 20 kg, bentonite 10 to 50 kg and zeolite 10 to 50 kg Soil improver manufacturing method using a dredged sludge, characterized in that The method of claim 1, In the soil improver manufacturing step, 1 to 5% of the additive in the dredging sludge cake weight ratio of the dredging sludge cake is mixed with a dredging sludge, characterized in that the soil improver manufacturing method.

Images