KR100502969B1 - Sludge dehydrant, preparing method thereof and dehydrating method of sludge with using this - Google Patents

Abstract

The present invention relates to a sludge dewatering agent capable of improving sludge dewatering ability generated during wastewater treatment, and more particularly, to a dewatering sludge dewatering apparatus capable of removing various heavy metals contained in a soft material generated during combustion of heavy oil, To a sludge dewatering agent for improving dewatering ability of sludge, a production method thereof, and a sludge dewatering method using the same.

When the sludge is dewatered using the sludge dewatering agent of the present invention, carbon is adsorbed between the flocs formed by the inorganic flocculant to form a water discharge passage, thereby efficiently discharging moisture from the sludge and adsorbing the odor, Can be reduced.

Description

Technical Field [0001] The present invention relates to a sludge dewatering apparatus using a heavy oil sludge, a method for producing the sludge dewatering apparatus, and a sludge dewatering method using the same,

The present invention relates to a sludge dewatering agent capable of improving the dehydration ability of sludge generated during wastewater treatment, and more particularly, to a sludge dewatering agent capable of removing various heavy metals contained in a soft material (hereinafter referred to as heavy oil sludge) And a sludge dewatering method using the recovered carbon component, and a sludge dewatering method using the sludge dewatering method.

As the industrialization progresses, the amount of wastewater from factories is increasing. In addition, water pollution becomes a serious social problem by increasing various living sewage and organic wastewater.

As a result, the amount of sludge generated during wastewater treatment is increasing. These sludges are dewatered by pressurized dehydrator, centrifugal dehydrator, vacuum dehydrator, etc. and caked and buried or incinerated. However, if the amount of water remaining in the dewatered sludge is large, the amount of sludge during landfilling is increased, and there is a problem that it is not burned well at the time of incineration.

Therefore, conventionally, inorganic or organic coagulants are used to concentrate inorganic sludge and organic sludge to form aggregation between particles using zeta potential and vander walls, and water And the water is discharged between the flocs formed through the crosslinking function using the polymer flocculant to make a dehydrated cake and dispose of it.

However, due to the characteristics of flocs, the conventional method described above has a weak cohesive force and a narrow range of coagulation. Therefore, the sludge characteristic is greatly influenced by sludge characteristics. Also, when the flock is mechanically pressurized, it obstructs the discharge of water and clogs the follicle of the dehydrator and increases the water content. And increased the pollution of the working environment due to the odor of corruption caused by the anaerobicization of the organic matter at the time of high concentration for dehydration.

Accordingly, the inventor of the present invention has developed a sludge dewatering agent that improves the dewatering ability of the sludge, and has developed a method of efficiently dewatering the wastewater sludge using the sludge dewatering agent.

SUMMARY OF THE INVENTION It is an object of the present invention to improve the deodorizing ability of a biochemical sludge by using a soft material generated after heavy oil combustion and to reduce the odor of a sludge And a method for producing the sludge dehydrating agent.

It is another object of the present invention to provide a method for efficiently dewatering a biochemical sludge using the sludge dewatering agent of the present invention.

Another object of the present invention is to contribute to cost reduction and environmental protection by recycling heavy oils.

Hereinafter, the sludge dewatering agent of the present invention and its production method will be described in detail.

The sludge dewatering agent of the present invention is produced using heavy oil sludge, which contains heavy metals, various kinds of oil, inorganic compounds and carbon.

The organic components were analyzed by using the heavy oil recovered at the dust collector of Yeosu Thermal Power Plant and the results are shown in Table 1.

ingredient Heavy oil 1 (wt%) Heavy oil 2 (wt%) Heavy oil 3 (wt%) Test Methods Carbon (C) 59.82 82.19 73.29 ASTM D 5373-93 Hydrogen (H) 0.84 0.84 0.88 Nitrogen (N) 0.82 1.13 1.07 Sulfur (S) 8.21 5.97 7.35 ASTM D 4239-97 Ashes (Ash) 18.40 7.47 11.37 ASTM D 5142-90 Calorific value 6,000 - 7,000 cal / g

Next, the heavy oil sample was dried at 110 ° C, and the dried heavy oil was dissolved in aqua regia (mixed acid of hydrochloric acid and nitric acid) and quantitated by ICP-AES using an inductively coupled plasma emission spectrometer. Table 2 shows the results.

ingredient Heavy oil 1 (wt%) Heavy oil 2 (wt%) Heavy oil 3 (wt%) V 5.88 2.59 3.52 Ni 3.12 1.29 1.69 Fe 3.72 0.23 0.30 Cu 0.01 tr tr Mg 0.02 0.01 0.01 Mn 0.02 tr tr Al 0.07 0.03 0.03 Zn 0.03 0.01 0.02 Na 0.67 0.29 0.41 Si 0.03 0.02 0.01 Ca 0.08 0.03 0.03 Ti 0.01 tr tr Pb 0.02 tr tr

As can be seen from Tables 1 and 2, the heavy oil contains 50 to 85% of carbon, and contains heavy metals and the like.

Accordingly, the present invention is to remove heavy metals contained in heavy oils and refine carbon.

The method for producing a sludge dehydrating agent according to the present invention comprises the steps of: leaching heavy oil sludge under an aqueous solution having a pH of 3.0 or less; Filtering the leach solution to remove heavy metals; And mixing the alkaline agent with the filtrate, which is the main component of the carbon obtained in the step (a).

If the pH is more than 3.0 in the leaching step, the heavy metal leaching efficacy under an acid atmosphere is inferior. The most preferred pH range is 1.0 to 2.5.

In the leaching process, the heavy metal contained in the heavy oil is leached into the solution.

When the leach solution is filtered, only heavy metals remain in the filtrate, and carbon and other inorganic substances remain in the filtrate. The main component of the filtrate is carbon.

When the alkaline agent is appropriately mixed with the filtrate, the sludge dehydrating agent of the present invention having an appropriate degree of alkalinity for sludge dewatering is completed. At this time, the amount of the alkaline agent to be mixed will depend on which sludge dewatering agent is to be dewatered.

In the leaching step of the sludge dehydrating agent production method of the present invention, hydrochloric acid, nitric acid, and sulfuric acid may be selectively used to adjust the pH.

When the heavy oil syrup is sufficiently acidic, the water alone maintains a pH of 3.0 or less, so there is no need to add an additional acidic solution. This is because the sulfuric acid ion is used because the proper concentration of the sulfate ion generated as a result of combustion in the heavy oil is present.

Further, in the method for producing a sludge dehydrating agent of the present invention, at least one or more alkaline chemicals selected from the group consisting of calcium hydroxide, caustic soda and sodium carbonate are used. Alkaline drugs selected from the above group can be mixed and used.

Particularly, when calcium hydroxide is used, the sulfate ion remaining in the purified filtrate is converted into gypsum, and the water permeability is improved due to the characteristics of carbon and gypsum contained therein.

In the method for producing a sludge dehydrating agent of the present invention, water may be further added during the alkaline drug mixing step.

The sludge dewatering agent of the present invention may be prepared in a liquid or solid state depending on the use.

The sludge dewatering agent of the present invention is a sludge dewatering agent that forms a water outflow passage between carbon particles in solid phase particles to smooth water discharge even under pressurized conditions to lower the moisture content of the dewatered cake (dehydrated sludge) Reduces the odor of the cake.

A method of dewatering a sludge using the sludge dewatering agent of the present invention is characterized in that an appropriate amount of ferric chloride or ferric sulfate is added as an inorganic flocculant to the sludge and an appropriate amount of the sludge dewatering agent of the present invention is added to the mixture, I will.

The filtration means may be a pressurized dehydrator, a centrifugal dehydrator, a vacuum dehydrator, or the like, and other conventional filtration means may be used.

The sludge dewatering method of the present invention is preferably performed at a pH of 4 to 7.

The amount of the inorganic flocculant used in the sludge dewatering method of the present invention and the sludge dewatering agent of the present invention will vary depending on the state and characteristics of the sludge to be treated.

When the sludge dewatering method of the present invention is used, the carbon contained in the sludge dewatering agent of the present invention is adsorbed between the flocs formed by the inorganic flocculant, thereby making the water discharge pathway and smooth water discharge.

That is, the sludge is formed into a thin film, not by the aggregation or crosslinking of the sludge, but by the water, and the volume of the dehydrated sludge becomes smaller.

The carbon contained in the sludge dewatering agent adsorbs the dissolved malodorous substances in the sludge, thereby removing odors. In addition, the concentration of the hydrate in the cake is reduced to improve the peeling of the filter cloth and the dehydrated cake, as well as to reduce the clogging of the filter cloth, thereby increasing the cleaning cycle of the filter cloth and improving the productivity and the life of the filter cloth.

The present invention will be described in more detail by way of the following examples.

Example 1

100 g of the heavy oil was dried at 110 캜, dissolved in 500 ml of water, and left at pH 2.5 for 1 hour to leach heavy metals. The leach solution was filtered to remove heavy metals. The filtrate obtained above was mixed with 50 g of slaked lime to prepare a solid sludge dewatering agent.

Example 2

100 g of a heavy oil, which is different from the heavy oil used in Example 1, was dried at a temperature of 110 ° C, placed in 500 ml of a sulfuric acid solution (pH 2.0), and left for 30 minutes to leach heavy metals. The leach solution was filtered to remove heavy metals. The filtrate obtained above was mixed with 1000 ml of water and 50 g of slaked lime to prepare a liquid sludge dewatering agent.

Example 3

3 ml of ferric sulfate (pH 4.02) was added to 100 ml of the petrochemical sludge, and 5 cc of the sludge dehydrating agent prepared in Example 2 was mixed. The mixture was filtered using a Buchner filtration apparatus and dehydrated to obtain a dehydrated cake.

Comparative Example 1

3 ml of ferric sulfate (pH 4.02) was added to 100 ml of petrochemical sludge and 5 cc of lime (30%) was mixed. The mixture was filtered using a Buchner filtration apparatus and dehydrated to obtain a dehydrated cake.

The comparison results of Example 3 and Comparative Example 1 are shown in Table 3.

sample pH Dewatered cake weight (g) Dry cake weight (g) Filtration time Example 3 6.5 15.14 4.31 3 minutes Comparative Example 1 6.2 15.84 5.28 3 minutes 5 seconds

As can be seen from Table 3, the filtration time of the sludge was not significantly different in Example 3 and Comparative Example 1, but the weight of the dehydrated cake and the dried cake in Example 3 using the sludge dehydrating agent of the present invention were 15.14 g and 4.31 g, respectively. The weight of the dehydrated cake and the dried cake in Comparative Example 1 dehydrated with calcium hydroxide was 15.84 g and 5.28 g, respectively. Therefore, it was confirmed that the dewatering efficiency was increased by using the sludge dewatering agent of the present invention.

Example 4

In Example 3, the filter cloth used in the filtration was used as it was and the same sample and method as in Example 3 were used, and the degree of clogging of the filter paper was observed.

Comparative Example 2

In Comparative Example 1, the filter cloth used in the filtration was used as it was and the same sample and method as in Comparative Example 1 were used, and the degree of clogging of the filter paper was observed.

The comparison results of Example 4 and Comparative Example 2 are shown in Table 4.

sample Filtration time Filter paper and degree of clogging Remarks Example 4 3 minutes 20 seconds slightly Comparative Example 2 4 minutes Severe

As can be seen in Table 4, the filtration time in Example 4 was 3 minutes and 20 seconds, which took less time than 4 minutes in Comparative Example 2. The filter paper and clogging degree were also worse in Comparative Example 2 than in Example 4 .

Test Example 1

5cc, 6cc, 7cc, 8cc and 9cc of the sludge dewatering agent prepared in Example 1 were respectively prepared, and the prepared sludge dehydrating agent was added to a mixture of 100 ml of petrochemical sludge and 3 ml of ferric sulfate (pH 4.02) The filtration time was measured and the time required was shown in Table 4.

Filtration time (min) Sludge dehydrating agent input (%) 3 5 2 6 2 7 2.5 8 2.5 9

As can be seen from Table 5, when the sludge dehydrating agent input amount was 6-7%, it was confirmed that the filtration took the shortest time.

Although specific embodiments of the present invention have been described above, it is apparent that the sludge dewatering agent of the present invention, the method for producing the sludge dewatering agent, and the dewatering method using the sludge dewatering agent may be variously modified by those skilled in the art.

For example, although the mixing ratio of each sample is specified in the above embodiment, the mixing amount may be changed depending on the state of the sludge to be dewatered. It can also be applied to wastewater treatment and so on to reduce organic matter. It should be understood, however, that such modified embodiments are not to be understood individually from the technical spirit and scope of the invention, and such modified embodiments are intended to be within the scope of the appended claims.

When the sludge is dewatered using the sludge dewatering agent of the present invention, the carbon is adsorbed between the flocs formed by the inorganic flocculant to form a moisture discharge path, thereby efficiently discharging moisture from the sludge. In addition, the carbon contained in the sludge dehydrating agent adsorbs the malodorous substance, thereby not only reducing the odor of the sludge but also adsorbing the toxic substance which inhibits the growth of the microorganism.

Further, when the sludge is dewatered using the sludge dewatering agent of the present invention, the amount of dewatered cake remaining after dewatering is reduced, and the amount of heat generated by the dewatered dewatering cake is high, so that fuel is reduced during incineration. In addition, this final dewatered cake can be recycled as a solid fuel replacement.

In addition, the present invention contributes to cost reduction and environmental protection by recycling the heavy fuel oil.

In particular, the sludge dewatering agent of the present invention is effective for treating biological sludge which is difficult to use inorganic flocculant or organic polymer flocculant.

Claims (11)

A method for producing a sludge dehydrating agent, Leaching the heavy oil under an aqueous solution of pH 3.0 or less; Filtering the leach solution to remove heavy metals; And And mixing an alkaline agent selected from the group consisting of calcium hydroxide, caustic soda and sodium carbonate into the filtrate containing carbon as a main component obtained in the above step. The method according to claim 1, Wherein the pH is in the range of 1.0 to 2.5 in the leaching step. 3. The method according to any one of claims 1 to 3, Wherein at least one or more selected from the group consisting of hydrochloric acid, nitric acid and sulfuric acid is further added in order to adjust the pH in the leaching step. delete The method according to claim 1, Wherein in the alkaline agent mixing step, water is further added. Wherein the heavy oil is leached under an aqueous solution having a pH of not higher than 3.0 and is filtered to remove heavy metals to prepare a filtrate and mixing the resulting filtrate with an alkaline chemical selected from the group consisting of calcium hydroxide, caustic soda and sodium carbonate, A sludge dewatering agent which improves dewatering ability of sludge by forming a water outflow passage by carbon. The method according to claim 6, Wherein the sludge dehydrating agent is in a liquid or solid phase. In the sludge dewatering process, Wherein the sludge is charged with ferric chloride or ferric sulfate and the sludge dehydrating agent according to claim 6 or 7 is added to the mixture and the sludge is dewatered by filtration means. 9. The method of claim 8, Wherein the filtration means is a pressurized dehydrator, a centrifugal dehydrator, and a vacuum dehydrator. 9. The method of claim 8, Wherein the sludge dewatering method is performed at a pH of 4 to 7. 9. The method of claim 8, And the dewatered cake remaining after filtration by the filtration means is recycled as fuel.