KR20080109980A - Manufacturing process for snow-removal agent of liquid-type including organic acid, snow-removal agent thereby, and test method thereof - Google Patents

Abstract

An organic acid-containing liquid deicing material is provided to produce an organic acid by introducing the organic sludge in waste water in a fermentor, thereby concentrating and manufacturing the organic acid solution. An organic acid-containing liquid deicing material comprises (a) a step for introducing the organic sludge of waste water from a sludge reservoir(1) to a fermentor(3); (b) a step for fermenting the organic compound of the organic sludge tp an organic acid with the microorganism within a fermentor; (c) a step for separating fermentation liquid of the inside of the fermentor; (d) a step for concentrating the organic acid solution; (e) a step for storing the concentrated organic acid solution; and (f) a step for adding the pH adjusting agent in the concentrated organic acid solution. The pH adjusting agent is the potassium hydroxide(KOH) of purity 80 - 100 %.

Description

Manufacturing process for snow-removal agent including organic acid, snow-removal agent of liquid-type including organic acid, snow-removal agent, and test method

1 is a schematic diagram of a wastewater treatment apparatus according to the present invention.

2 is a graph showing the result of the organic acid fermentation of the present invention according to the change of pH.

Figure 3 is a graph showing the result of the organic acid fermentation of the present invention with the change of temperature.

Figure 4 is a graph showing the result of the organic acid fermentation of the present invention according to the change of the sludge residence time.

5 is a graph showing the results of the organic acid fermentation of the present invention according to the change of the organic load.

Figure 6 is a graph comparing the pH of each of the fermentation broth, microfiltration effluent and reverse osmosis concentrate according to the present invention.

Figure 7 is a graph comparing the total solids concentration and total dissolved solids concentration of each of the fermentation broth, microfiltration effluent and reverse osmosis concentrate according to the present invention.

Figure 8 is a graph comparing the COD concentration of each of the fermentation broth, microfiltration effluent and reverse osmosis concentrate according to the present invention.

9 is a graph comparing the melting amount of the conventional wet salt and the snow removing agent of the present invention.

Figure 10 is a photograph of the result of the actual spraying the conventional salt and the present snow removal agent.

11 is a graph comparing the chlorine ion concentration of the conventional salt salt and the snow removing agent of the present invention.

** Description of the symbols for the main parts of the drawings **

1: sludge storage tank 2: hot water tank

3: fermenter 4: microfiltration module

5: filtrate storage tank 6: excess sludge storage tank

7: reverse osmosis module 8: concentrated organic acid reservoir

9: reverse osmosis filtered water 10: detergent storage tank

The present invention relates to an organic acid-containing liquid snow removing agent through acid fermentation of organic sludge such as waste water sludge and food waste. Specifically, by using organic sludge having a high content of organic materials, fermenting it, separating the fermentation broth into solid solution, and concentrating it at a high concentration to develop a liquid environment friendly deicer (LEFD) containing a high concentration of organic acid. It is about.

Soluble organic matter (organic acid or lower fatty acid) produced by acid fermentation from organic sludge such as wastewater sludge and food waste can not only be used as an external carbon source for biological nitrogen removal process for wastewater, but also as a basic material of polymer materials. Its use is expanding.

The organic acid may also be utilized as a liquid eco-friendly snow removing agent. That is, currently used snow removing agents include sodium chloride (NaCl) and calcium chloride (CaCl ₂ ), and are mainly used for smooth highway traffic when it is snowed in a cold place in winter. The purpose of spraying snow remover on highways, bridges, etc. is to melt snow on the road, prevent re-freezing of water on the road, and to make snow removal easier by removing snow from the road surface. To improve the sliding friction coefficient.

However, due to the toxicity of chlorine ions contained in the above-mentioned snow removal agents, they cause serious damage such as corrosion of various cement concrete buildings, roads, bridges, automobiles, underground wire cables, and water and sewage pipes. Melting and flowing into rivers or lakes are causing various environmental problems such as destruction of aquatic ecosystems, pollution of drinking water, and damage to plants around roads.

However, organic acids such as acetic acid produced through acid fermentation of waste water have similar ice-making effects due to the freezing point drop to sodium chloride, and have very low corrosiveness and are biodegradable by bacteria after dissolving in water, so that there is little risk of environmental pollution. It has many advantages.

Therefore, when organic acid is produced through acid fermentation from organic sludge such as waste water, two effects of waste water treatment and liquid type eco-friendly snow removing agent can be achieved at low cost.

However, organic acid fermentation using organic sludge in wastewater has low fermentation efficiency because it is difficult to maintain high concentrations of microorganisms in fermentation broth. It is strongly demanded. In addition, there is no reproducible test method for objectively evaluating the effect of the produced snow remover, which has been a major obstacle for the user to properly select the snow remover.

The present invention has been made in order to solve the above problems, by introducing an organic sludge in the waste water into the fermentation tank to produce an organic acid, after separating the fermentation broth solid-liquid, the concentrated organic acid aqueous solution to produce an organic snow removal agent It is an object of the present invention to provide a method for producing a liquid-containing snow removing agent.

In addition, another object of the present invention is to provide an organic acid-containing liquid snow removing agent prepared by the above method.

Furthermore, another object of the present invention is to provide a test method for an organic acid-containing liquid snow removal agent that evaluates the snow removal effect of a snow removal agent.

The method for preparing an organic acid-containing liquid snow removing agent of the present invention is characterized by including the following steps to achieve the object as described above:

(A) introducing organic sludge of wastewater from the sludge storage tank into the fermentation tank;

(B) fermenting the organic material of the organic sludge with an organic acid by microorganisms in the fermenter;

(C) solid-liquid separation of the fermentation broth in the fermenter;

(D) concentrating the solid-liquid separated organic acid aqueous solution; And

(E) storing the concentrated organic acid solution.

In addition, the production method of the present invention after the step (e),

(F) adding a pH adjuster to the concentrated aqueous organic acid solution

It is preferable to further include.

In addition, the pH adjusting agent is preferably potassium hydroxide (KOH) with a purity of 80 to 100%.

Furthermore, after step (c) and before step (d),

(G) storing the solid-liquid separated organic acid aqueous solution in a storage tank

It is preferable to further include.

In addition, it is preferable that the step (d) further comprises the step of analyzing the components of the aqueous organic acid solution and the water separated therefrom.

In addition, the solid-liquid separation of the step (c) is preferably made by a microfiltration process.

In addition, the fermenter is preferably provided with a stirrer and temperature controlled.

In addition, the membrane of the microfiltration preferably has a nominal pore size of 0.01 to 0.5 ㎛.

In addition, the separation membrane of the microfiltration is preferably a ceramic material.

In addition, the concentration of the step (d) is preferably made by a reverse osmosis process.

In addition, the osmosis membrane of the reverse osmosis is preferably a desalination rate of 95 to 99.9%.

On the other hand, the organic acid-containing liquid snow removal agent of the present invention is characterized in that it is prepared by the above method.

In addition, the organic acid-containing liquid snow removing agent test method of the present invention is characterized in that it comprises the step of spraying the organic acid-containing liquid snow removing agent on snow or ice, and measuring the volume of molten snow or ice.

In addition, in the test method of the organic acid-containing liquid snow removing agent, the spraying amount of the snow removing agent is preferably 1 to 10 parts by weight per 100 parts by weight of the snow or ice.

In addition, in the test method of the organic acid-containing liquid snow removing agent, it is preferable that the volume measurement of the molten snow or ice is measured at intervals of 1 to 30 minutes and then accumulated.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, in the following description, many specific details such as specific components are disclosed, which are provided to help a more general understanding of the present invention, and the present invention may be practiced without these specific details. It will be self-evident to those of ordinary knowledge. In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

First, some terms used in the specification of the present invention are defined as follows.

Waste water in the present specification refers to BOD or BOD when discharged directly to rivers or oceans, such as wastewater from sewage, sewage, and livestock wastewater having a high organic content, drainage discharged from colony drainage facilities such as aquaculture farms, and leachate generated from food waste. The concept includes all the wastewater that causes water pollution due to the increase of COD.

In addition, organic sludge refers to an organic substance that is a direct cause of BOD or COD increase as a constituent of the wastewater, and includes microorganisms which ferment organic substances in sludge to produce organic acids and organic substances that are nutrient sources of the microorganisms. Doing.

In addition, the molten amount means the amount of change in the state of the solid substance absorbs energy to the liquid state, in the present invention, by spraying the amount of ice melted in 10 minutes after spraying the snow removal agent by the syringe It was obtained by measuring the cumulative volume of the snow removal agent over time.

Meanwhile, the wet salt spray refers to a method of spraying a snow removing agent that is currently carried out during highway snow removing work, and refers to spraying a mixture of sodium chloride in a weight ratio of 3: 7 in a 30% calcium chloride solution, which has a high ratio of chloride. It is a kind of high chloride snow removal agent.

The organic acid-containing liquid snow removing agent manufacturing method of the present invention will be described with reference to FIG. 1.

First, organic sludge in the waste water is introduced into the fermentation tank 3 from the sludge storage tank 1. In the fermentation tank (3), a breathable acid fermentation is performed in which nutrients such as proteins, fats and carbohydrates in the sludge are converted into organic acids by microorganisms present in the organic sludge. However, unlike the general fermentation process, it is difficult to optimize the fermentation conditions for growth of the microorganisms and organic acid fermentation in waste water, which has a low fermentation efficiency. Therefore, in order to produce a large amount of organic acid per unit time, it is necessary to maintain a high concentration of microorganisms inside the fermentation tank 3 above all.

In addition, the optimum conditions of the organic acid fermentation are most affected by pH, sludge retention time (SRT), temperature and organic load. Optimum fermentation conditions in the present invention is a pH of 5.5 to 6.5, SRT within 10, the higher the temperature, the efficiency is increased, but considering the energy consumption side and the odor generated during fermentation in the medium-temperature fermentation region 30 ~ 35 ℃ It is desirable to implement, and organic loading does not have a significant effect on organic acid conversion.

In order to maintain the microorganisms in the fermentation tank 3 at a high concentration as described above, it is preferable to solid-separate the fermentation broth in the fermentation tank 3. That is, the liquid component containing a product such as an organic acid in the fermentation broth and a solid component such as a microorganism are separated, the liquid component is discharged and the solid component is recycled back to the fermentation tank 3, and consequently the microorganisms in the fermentation tank 3 It is to keep the concentration high.

Various methods such as filtration, centrifugation, and sedimentation may be used for the solid-liquid separation of the fermentation broth, and in the present invention, particularly, a microfiltration process is preferable. That is, when a part of the fermentation broth in the fermentation tank 3 is transferred to the cross filtration microfiltration module 4 as shown in FIG. Microorganisms having a large particle diameter but passing through the separation membrane are not returned to the fermentation tank 3 without passing through the separation membrane. Accordingly, the concentration of microorganisms in the fermenter 3 can be maintained at a high concentration, resulting in an increase in the rate of organic acid production. Furthermore, due to the presence of the microfiltration module 4, it is possible to reduce the operation load of the organic acid enrichment process at the rear end, thereby ensuring stable operation of the process.

The organic acid aqueous solution of the liquid component of the solid-liquid separated fermentation broth is subjected to a concentration step to increase the concentration of the organic acid desired in the present invention. In this case, distillation, extraction, adsorption, precipitation, membrane separation and the like may be subjected to, in the present invention, it is preferable to go through the reverse osmosis process which is one of the membrane separation process.

The mixture of organic acid and water passed through the separator of the microfiltration module 4 of FIG. 1 is transferred to the reverse osmosis module 7 for concentration of the organic acid. The osmosis membrane of the reverse osmosis module 7 has a smaller membrane pore diameter than the separation membrane of the microfiltration module 4 so that small molecules such as water pass but large molecules such as organic acids do not pass. Therefore, when a mixture of organic acid and water is introduced into the reverse osmosis module 7 and pressure is applied, only water passes through the osmosis membrane, resulting in concentration of the organic acid.

The concentrated organic acid aqueous solution is preferably stored in a separate storage means, for example, the concentrated organic acid storage tank 8 as shown in FIG. 1 to prepare for future use.

On the other hand, the stored concentrated organic acid solution is preferably carried out pH adjustment through a pH adjuster in a range that does not impair the snow removal efficiency. Although the organic acid snow remover of the present invention is more environmentally friendly than the conventional chlorine snow remover, it is obvious that a very low pH will inevitably have a negative effect on the ecosystem. In the present invention, it is particularly preferable to use potassium hydroxide (KOH) having a purity of 80 to 100% as the pH adjuster.

Further, the filtrate obtained as a result of the solid-liquid separation of the fermentation broth of the fermentation tank 3 by step (c) is more preferably temporarily stored in the filtrate storage tank 5 prior to the separate concentration process described above. This results in temporary storage of the filtrate when the concentration process does not function normally during operation, resulting in increased flexibility of the operation and consequently improved stability of the entire process.

Further, it is more preferable to carry out the component analysis of the aqueous organic acid solution concentrated by step (d) and the water separated therefrom. The concentrated organic acid aqueous solution may be used directly for the use of a snow removing agent, etc., it is preferable to analyze the components such as pH before actual use. In addition, the water separated from the concentrated organic acid aqueous solution is also often discharged immediately, it is necessary to analyze whether it meets the discharged water treatment standards. Such concentrated treated water (reverse osmosis filtered water corresponding to 9 in FIG. 1) may be discharged as it is or may be subjected to a separate post-treatment process according to the analysis result.

On the other hand, the fermentation tank (3) is preferably provided with a stirrer in order to improve the material transfer and mixing efficiency, the hot water jacket (jacket) or a separate hot water tank as shown in Figure 1 to maintain the optimum temperature of acid fermentation It is preferable that temperature is controlled by hot water supplied from (2).

In addition, when the concentration of microorganisms or nutrients in the fermentation tank 3 is too high, the rate of acid fermentation is also lowered, so it is necessary to remove some of the sludge from the fermentation tank 3, and such excess sludge is stored in a separate excess sludge storage tank 6 It is preferable to transfer and store in). The sludge stored in this excess sludge storage tank 6 may also be transferred to the fermentation tank 3 as needed to be used for fermentation.

On the other hand, in the separation membrane of the microfiltration module 4, the pores of the separation membrane are blocked or contaminated by the solids as the fermentation broth is mixed with various components, and the filtration rate tends to decrease rapidly. If such contamination is left for a long time, the contaminants accumulate and compress in the through holes, thereby permanently blocking the through holes, making recovery of the filtration efficiency impossible.

Therefore, the microfiltration module 4 of the present invention preferably cleans the through-holes of the separator periodically by the microfiltration backwashing module. Specifically, the detergent storage tank 10 constituting the microfiltration backwashing module together with a pump is provided. It is necessary to periodically clean the through-holes by pressurizing and supplying a cleaning agent such as a cleaning liquid such as air, ozone, water or the like in a direction opposite to the filtration direction.

The separation membrane of the microfiltration module 4 of the present invention preferably has a nominal pore size of 0.01 to 0.5 μm, but when the separation membrane is less than 0.01 μm, the filtration rate is too slow and the operating pressure is high, which leads to an unnecessary increase in operating costs and contamination of the membrane. On the contrary, when it exceeds 0.5 μm, the purity of the final organic acid is reduced, and the probability of occurrence of contamination of the osmosis membrane of the reverse osmosis module 7 is increased.

And, the material of the separator of the microfiltration module 4 is preferably a ceramic bar, this ceramic material has the advantage of excellent performance in terms of oxidation resistance. Furthermore, the separator is preferably in the form of a tube.

In addition, the osmosis membrane of the reverse osmosis module 7 is preferably used in the desalination rate of 95 to 99.9%. The osmosis membrane having a desalination rate of less than 95% may include some of the low molecular weight organic acid in the filtered water 9, and the osmosis membrane having a desalination rate of more than 99.9% has a problem that the membrane permeation rate is too slow and the operating pressure is excessively increased.

Furthermore, the organic acid concentrated through the wastewater treatment method of the present invention may be used as a liquid-type eco-friendly snow removing agent as described above through the necessary additional treatment such as the pH adjustment described above.

On the other hand, the organic acid-containing liquid snow removing agent of the present invention can be evaluated for its performance by spraying it on snow or ice and measuring the volume of molten snow or ice.

Although there have been many solid or liquid snow removal agents in the past, it is difficult to compare the performance of each snow removal agent because there is no criterion to evaluate the snow removal effect. In particular, the comparison was more difficult when the properties of the snow removal agent were different between solid and liquid.

In order to overcome this problem, the present invention is to provide a test method of a snow removing agent is another object.

In the snow removing agent test method of the present invention, after distilled water is poured into a predetermined container, such as a test dish, and frozen, 1 to 10 parts by weight of a snow removing agent per 100 parts by weight of the distilled water is sprayed onto the frozen distilled water, followed by an interval of 1 to 30 minutes. This is determined by measuring the amount of ice melted and then accumulating it.

When the amount of the snow removal agent is less than 1 part by weight per 100 parts by weight of distilled water, the amount of melted ice may be too small, so that accurate evaluation may be difficult. When the amount of the snow removal agent exceeds 10 parts by weight, the amount of the snow removal agent is almost reduced even if the amount of snow removal agent is increased. The phenomenon that does not increase may occur.

In addition, when the measurement time interval is less than 1 minute, too little melting may occur as well, and when it exceeds 30 minutes, the problem of melting all the ice in one or two times may occur.

The snow removing test method of the present invention can be used not only in the organic acid-containing liquid snow removing agent of the present invention, but also can function as a direct test method for all other forms of snow removing agent.

EMBODIMENT OF THE INVENTION Hereinafter, the Example of this invention is described.

Example

Example  1: organic acid fermentation

Organic acid fermentation was carried out with varying pH, temperature, sludge residence time and organic load. As a result of the organic acid fermentation, the organic acid concentration and the organic acid conversion rate are shown in FIGS. 2 to 5.

Example  2: solid-liquid separation and concentration

After the organic acid fermentation was performed at pH 6.0 and the fermentation temperature at 35 ° C., the physical properties of the fermentation broth immediately after the fermentation, the microfiltration effluent after solid-liquid separation, and the reverse osmosis concentrated water after concentration were shown in FIGS. 6 to 8. Solid-liquid separation was performed with a microfiltration membrane with a membrane pore diameter of 0.5 μm (membrane filtration rate of 80%), and the concentration was performed by applying a filtration pressure of 1 MPa to a reverse osmosis module having an osmosis membrane with a desalination rate of 99%. The properties investigated were pH, total solids concentration, total dissolved solids concentration, and COD concentration.

Test Example

Using a conventional salt salt containing sodium chloride in a weight ratio of 3: 7 in a 30% calcium chloride solution and the organic acid snow removing agent of the present invention, the temperature of minus 5 ℃ and minus 10 ℃ The amount of melt at was measured, and the results of observing the snow removal condition when sprayed on the actual road are shown in FIGS. 9 and 10, respectively. In addition, the chlorine ion concentrations of the two snow removing agents were compared with FIG. 11. At this time, the melt amount was measured by freezing 130 g of distilled water in a test dish, and then evenly spraying 4.17 g of a snow removing agent on an ice plate, and accumulating the amount of ice melted by a syringe for 10 minutes.

In the case of organic acid fermentation, the pH of the organic acid was changed to 4.5, 5.5, 6.5, and 7.5. As a result, as shown in FIG. 2, the highest organic acid concentration was shown at a pH of 5.5 to 6.5.

In addition, as shown in FIG. 3, the higher the organic acid was produced, the higher the temperature was. It became.

As shown in FIG. 4, the longer the sludge residence time was, the higher the organic acid conversion was. The organic load did not significantly affect the organic acid conversion as shown in FIG. 5.

On the other hand, as a result of examining the physical properties of each of the treatment solution subjected to microfiltration and reverse osmosis after organic acid fermentation, as shown in FIG. 6, it can be seen that the pH decreases as the concentration of the organic acid increases as the step proceeds.

And, as shown in Figure 7, the concentration of the total solids showed the highest value in the fermentation broth containing microorganisms, the concentration was reduced in the microfiltration and reverse osmosis treated water from which the microorganisms were removed. In particular, comparing the microfiltration effluent and the reverse osmosis concentrated water, it can be seen that the organic acid concentration was further increased by the concentration through the reverse osmosis process. This trend can be seen in the COD concentration change of FIG. 8, and the COD concentration was higher in the microfiltration effluent and the reverse osmosis concentrated water than in the fermentation broth itself. The reason for showing the highest COD in the microfiltration effluent is that the microfiltration effluent contains more organic matter than the fermentation broth that is not concentrated at all, and may contain other organic matters, which is lower than the reverse osmosis concentrate. It seems that COD concentration is high even at the concentration.

9 and 10 show the results of ice melting using the conventional salt salt and the organic acid snow removing agent of the present invention, and it can be seen that the snow removing effect is similar to that of the conventional snow removing agent.

First of all, the snow removal agent of the present invention has a high snow-removing effect in that the snow removal agent of the present invention exhibits the above-mentioned snow removal effect while showing a significantly lower chlorine ion concentration than the conventional wet salt snow removal agent as shown in FIG. 11. can confirm.

Although the above has been illustrated and described with respect to the preferred embodiments of the present invention, the present invention is not limited to the specific embodiments described above, those skilled in the art without departing from the gist of the present invention various modifications Of course, implementation is possible. Therefore, the scope of the present invention should not be construed as being limited to the above embodiments, but should be defined by the claims below and equivalents thereof.

As described above, the manufacturing method of the organic acid-containing liquid snow removing agent of the present invention is an acid fermentation process for producing an organic acid using organic sludge as a raw material, and a solid-liquid separation process for separating the fermentation broth generated from the fermentation product of the process into a solid component and a liquid component. Concentration process to concentrate the effluent separated from. This is to separate the solids contained in the fermentation sludge for high concentration of the organic acid, which is the final goal, and then to effectively concentrate the organic acid at low cost in the concentration process.

In addition, the manufacturing method of the present invention has the advantage of recovering useful materials from sludge which is inevitably generated during the treatment of sewage and wastewater, and the amount of sludge to be disposed of finally reduced. Furthermore, the organic acid, which is a fermentation product, can be used in the synthesis of various basic materials, and in particular, it can be used as a liquid eco-friendly snow removal agent with low salt content that adversely affects the surrounding environment.

In addition, as a reproducible and objective test method for snow removal agent is provided, the user of the snow removal agent can appropriately select a snow removal agent and its quantity according to the purpose, and drastically reduce the environmental pollution caused by the use of conventional snow removal agent indiscriminately. It also has advantages.

Claims (9)

Method for producing an organic acid-containing liquid snow removal agent comprising the following steps: (A) introducing organic sludge of wastewater from the sludge storage tank into the fermentation tank; (B) fermenting the organic material of the organic sludge with an organic acid by microorganisms in the fermenter; (C) solid-liquid separation of the fermentation broth in the fermenter; (D) concentrating the solid-liquid separated organic acid aqueous solution; And (E) storing the concentrated organic acid solution. The method of claim 1, wherein after step (e), (F) adding a pH adjuster to the concentrated aqueous organic acid solution Method for producing an organic acid-containing liquid snow removal agent comprising a further. The method of claim 2, The pH adjusting agent is a method of producing an organic acid-containing liquid snow removal agent, characterized in that the purity of 80 to 100% potassium hydroxide (KOH). The method of claim 1, wherein after step (c) and before step (d): (G) storing the solid-liquid separated organic acid aqueous solution in a storage tank Method for producing an organic acid-containing liquid snow removal agent comprising a further. The method of claim 1, The method of preparing an organic acid-containing liquid snow removing agent, characterized in that it further comprises the step of analyzing the components of the aqueous organic acid solution and the water separated therefrom concentrated by the step (d). An organic acid-containing liquid snow removal agent prepared by the method of any one of claims 1 to 5. A method for testing an organic acid-containing liquid snow removing agent comprising the step of spraying the organic acid-containing liquid snow removing agent of claim 6 on snow or ice and measuring the volume of the melted snow or ice. The method of claim 7, wherein The spraying amount of the organic acid-containing liquid snow removing agent is 1 to 10 parts by weight per 100 parts by weight of the snow or ice. The method according to claim 7 or 8, The volume measurement of the molten snow or ice is measured at intervals of 1 to 30 minutes and then accumulating them.

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