KR20160136521A - Method for treating sewage sludge using adjuvant flocculants for scale preventer - Google Patents

Method for treating sewage sludge using adjuvant flocculants for scale preventer Download PDF

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KR20160136521A
KR20160136521A KR1020150069835A KR20150069835A KR20160136521A KR 20160136521 A KR20160136521 A KR 20160136521A KR 1020150069835 A KR1020150069835 A KR 1020150069835A KR 20150069835 A KR20150069835 A KR 20150069835A KR 20160136521 A KR20160136521 A KR 20160136521A
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ferric sulfate
sludge
basic ferric
concentration
addition
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KR1020150069835A
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KR101956599B1 (en
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테이지 누카야
이종민
유종영
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(주) 폴리테츠코리아
주식회사 서남환경
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Priority to KR1020150069835A priority Critical patent/KR101956599B1/en
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Priority to KR1020190025266A priority patent/KR102320633B1/en
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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
    • C02F11/14—Treatment of sludge; Devices therefor by de-watering, drying or thickening with addition of chemical agents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
    • C02F11/121—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering
    • C02F11/127—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering by centrifugation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F5/00—Softening water; Preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents
    • C02F5/08—Treatment of water with complexing chemicals or other solubilising agents for softening, scale prevention or scale removal, e.g. adding sequestering agents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2303/00—Specific treatment goals
    • C02F2303/06—Sludge reduction, e.g. by lysis

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Treatment Of Sludge (AREA)

Abstract

According to an aspect of the present invention, in a method for drying and treating digested sludge generated in a biological sewage sludge treatment process, provided is a sewage sludge treatment method using a coagulant aid for suppressing scale production, comprising: a scale suppressing coagulant aid injection step of injecting ferric basic sulfuric acid with 1000-2,000 mg/L ranges against the digested sludge; a polymer coagulant injection step of injecting cationic polymer coagulant with 230-380 mg/L ranges after the injection step of the coagulant aid for the suppressing scale production; a step of drying the sludge passing through the polymer coagulant injection step by a drying device.

Description

TECHNICAL FIELD The present invention relates to a method for treating sludge using flocculant for scale inhibition,

The present invention relates to a method for treating sewage sludge using a coagulation aid for inhibiting scale formation.

In the biological sewage treatment process, the sewage is aerated in the aeration tank, and the aerated sewage is allowed to settle in the activated sludge for a suitable period of time in the final sedimentation tank, and the treated water is discharged to the stream again.

After the precipitated activated sludge is sent to the digester, it undergoes an anaerobic digestion process, and the digested sludge is sent to the dehydrator to reach the dehydration process.

In the dewatering process, a dewatering device such as a centrifugal separator or a pressurized press dehydrator is used to reduce the weight and volume of the sludge cake generated after dewatering.

At this time, high concentrations of phosphate ions, magnesium ions, and ammonium ion substances contained in the digested sludge generate strobytes, which adhere to the sludge transfer piping and dewatering equipment, thereby reducing sewage treatment efficiency.

In the chemical wastewater treatment process, a large scale is generated during the reaction between the chemical agent injected for wastewater treatment and the desulfurization wastewater, and a scale is attached to the inside of the wastewater treatment facility, so that the chemical treatment of the desulfurization wastewater A large amount of scale is adhered to the primary reaction tank, the primary pH adjustment tank and the daily wastewater storage tank.

In the biological sewage treatment process, scale formation is likely to occur in sludge piping or dehydration separation piping rather than primary treatment or digestion trough, since the ratio of surface area and volume greatly affects scale production.

Particularly, in a separate liquid pipe of a centrifugal dehydrator, pH is elevated due to rapid decarbonation, and crystals are likely to be formed.

Such a scale-related failure occurs throughout the dehydration process, and is particularly generated in a portion where the pipe becomes narrow and a rear end portion such as a valve.

A method for removing struvite produced by such crystals by adding an anti-scale agent periodically has been studied.

When struvite is generated, it can be removed by pipeline cleaning or sulfuric acid addition method, but the dehydrator must be stopped every time the pipe is cleaned. When diluted sulfuric acid is added to the storage tank for preventing scale, The problem is that it is not easy to handle the drug itself.

Therefore, in the treatment of sludge generated in the biological sewage treatment process, an economical sewage sludge treatment capable of suppressing the production of the strobite occurring in the sludge transfer pipe by adding the flocculant polymer flocculant and the scale- Method is required.

The background of the present invention is disclosed in Korean Patent Registration No. 10-0573186 (Method of treating flue gas desulfurization wastewater using a scale formation inhibitor).

Korean Patent Publication No. 10-0573186 discloses a method for preventing formation of scales by using a scale formation inhibitor against a scale generated in a chemical wastewater treatment process.

Korean Patent Registration No. 10-0573186 (Flue gas desulfurization wastewater treatment method using scale inhibitor)

It is an object of the present invention to provide a process for treating sludge generated in biological sewage treatment, which comprises adding a flocculant-forming polymer flocculant and a scale formation inhibitor having a synergistic reaction to the sludge- And to provide an economical sewage sludge treatment method.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG.

According to an aspect of the present invention, there is provided a method of dewatering digested sludge generated in a biological sewage treatment process, the method comprising the steps of: injecting basic ferric sulfate into the digested sludge in a range of 500 to 4,000 mg / L; A coagulant aid injecting step; A step of adding a polymer flocculant to the cationic polymer flocculant in a range of 100 to 400 mg / L after the step of adding the flocculant aid for inhibiting scale formation; And dewatering the sludge after the polymer flocculant injection step by a dewatering device; A method for treating sewage sludge using the coagulation aid for scale formation inhibition is provided.

Further, the basic ferric sulfate is added at 1,500 mg / L in the step of adding the coagulation assistant.

The coagulant aid may be added to a storage tank where digestion sludge can temporarily be stored between the digestion tank and the dehydration apparatus, and mixed with the digestion sludge.

The basic ferric sulfate has a specific gravity (based on 20 ° C) of 1.4 to 1.6, a PH 2 or more, a total-Fe of 10% or more, ferrous (Fe 2+ ) 0.07% or less.

The basic ferric sulfate is characterized by being formed of the following molecular formula.

Fe 2 (OH) n (SO 4 ) 3-n / 2 (0 <n? 2)

The basic ferric sulfate is a three-dimensional coordination form in which a part of SO 4 2- of ferric sulfate is replaced with OH - , and OH groups are polymerized as crosslinking to form a polynuclear complex.

The basic ferric sulfate is characterized in that the amount of the basic ferrous sulfate is set so that the concentration of the soluble magnesium in the dehydrated separation liquid generated in the dehydration apparatus is 10 mg / L or more.

The amount of the basic ferric sulfate to be added is characterized by setting the insoluble magnesium concentration, which is the difference between the total magnesium concentration and the soluble magnesium concentration in the dehydrated separation liquid generated in the dehydration apparatus, to 10 mg / L or less.

According to the second dehydration dehydration method using basic ferric sulfate in a centrifugal dehydrator according to an embodiment of the present invention, the addition of basic ferric sulfate increases the concentration of S-Mg in the separated solution, Inhibitory effect can be obtained.

According to the results of the dehydration dehydration method using dehydration method using two kinds of drugs of the polymer coagulant and the basic ferric sulfate in the centrifugal dehydrator according to the embodiment of the present invention, the dehydration cake water content was 77.3% when the polymer flocculant alone was administered Of the ferric sulfate is reduced to 75.0% (2.3% reduction) when 1,500 mg / L of basic ferric sulfate is added.

Also, the addition of ferric sulfate has an effect of reducing the dehydration cake of about 9%.

Figure 1 shows a biological sewage treatment process for general domestic sewage.
2 shows an example in which a scale is formed on a conventional digester sludge conveying pipe.
FIG. 3 shows an example of a sewage sludge treatment process using a scale formation inhibitor according to an embodiment of the present invention.
FIG. 4 shows the water content and the hydraulic pressure characteristics of the centrifugal dehydrator according to the input of basic ferric sulfate in an experimental example according to an embodiment of the present invention.
5 is a graph showing the relationship between total magnesium (T-Mg) and soluble magnesium (S-Mg) in a dehydration separation liquid in a dehydrator according to an embodiment of the present invention in a dehydrator according to the input of basic ferric sulfate will be.
FIG. 6 shows an image obtained by comparing scale formation according to the input of basic ferric sulfate in an experimental example according to an embodiment of the present invention.
FIG. 7 is a graph showing changes in the SS concentration of the dehydrated and separated water in the dehydrator according to the experimental example of the present invention, when the basic ferric sulfate was added.
FIG. 8 is a graph showing changes in the TP concentration of the dehydrated and separated water in a dehydrator according to an experiment according to an embodiment of the present invention as a result of the addition of basic ferric sulfate.

While the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and similarities.

It is also to be understood that the terms first, second, etc. used hereinafter are merely reference numerals for distinguishing between identical or corresponding components, and the same or corresponding components are defined by terms such as first, second, no.

It is to be understood that the specific embodiments are not intended to limit the invention to the specific embodiments, but are to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

In the following description, the same reference numerals are used for similar parts throughout the specification.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a biological treatment process for general domestic sewage.

1, organic wastewater or municipal sewage 31 flows into the initial sedimentation basin 11 to sediment the inflow sewage water while staying at a slow flow rate for about 2 hours (here, BOD (Biochemical Oxygen Demand) and SS (Suspended Solid) is removed by about 30%.)

In the next aeration tank 12, the aeration process is performed by blowing the air as a whole during a proper residence time. In the aeration tank 12, the microorganisms take up the organic matter, grow and reproduce, and make the organic matter into a microbial mass (activated sludge).

The aeration water 32 is allowed to settle for a suitable time (about 3 hours) in the final settler 13 to precipitate the activated sludge.

The activated sludge precipitated in the final sedimentation tank 13 is again sent to the aeration tank 12 to be kept active and the remaining activated sludge is sent to the digester 14.

In the digester 14, about 50% of the organic matter is decomposed in the anaerobic state and methane gas, which can be used as a combustible material, is generated.

The digested sludge in the digestion tank 14 is sent to the dewatering device 15 to reach the dewatering process.

In the dewatering process, a dewatering device 15 such as a centrifugal separator or a pressurized press dehydrator is used to reduce the weight and volume of the sludge cake 21 generated after dewatering.

In order to increase the dewatering efficiency of the sludge cake 21 and reduce the water content, the digested sludge is mixed with the polymer flocculant, which is a drug for flocculation, through the drug injector 16 immediately before the dewatering and is dehydrated by the dewatering device 21.

The sludge cake obtained by dewatering the coagulating agent has a water content of about 76 to 80%.

In the digested sludge or the dehydrated separation liquid, phosphate ions, magnesium ions and ammonium ions are liable to exist at a high concentration. When the pH is around 7 to 8, strobytes (MAP: MgNH4PO4.6H2O, ammonium phosphate monosaccharide, Or MAP)) is generated. This eventually becomes the scale, closing the sludge pipe and the dehydration separation liquid pipe.

According to an experiment according to an embodiment of the present invention, the solubility of the scale (strobite, MAP) generated in the digestion sludge conveying pipe increases in acidity, tends to decrease in alkalinity, and hardly dissolves in pH 8. Further, the solubility decreases as the temperature rises in a temperature range of 20 占 폚 or higher.

Particularly, in a separate liquid pipe of a centrifugal dehydrator, pH is elevated due to rapid decarbonation, and crystals are likely to be formed.

2 shows an example in which a scale is formed on a conventional digester sludge conveying pipe.

2 (a) shows the scale of the strobite (MAP) formed in the dehydrator inlet piping, and FIG. 2 (b) shows the scale of the strobite (MAP) at the rear end of the valve flow of the sludge conveying pipe .

FIG. 3 shows an example of a sewage sludge treatment process using a scale formation inhibitor according to an embodiment of the present invention.

2, the digested sludge digested in the digestion tank 14 is transferred to the storage tank 25 through the extinguishing transfer pipe 42. The coagulation assistant for inhibiting scale formation is injected from the flocculation auxiliary tank 51 according to an embodiment of the present invention before the introduction of the polymer flocculant as the main flocculating agent at the inlet end of the storage tank 25 or the storage tank 25.

The main coagulant according to an embodiment of the present invention is a cationic polymer flocculant including polyaminomethylacrylamide, polyethyleneamine, and the like .

The coagulation aid for inhibiting scale formation according to an embodiment of the present invention is basic ferric sulfate.

As a result of various experiments, the coagulation assistant for inhibiting scale formation according to an embodiment of the present invention not only inhibits scale formation but also increases the dehydration efficiency by synergism with the main coagulant, Is replaced with OH- and the OH group is polymerized as a crosslinking to form a polynuclear complex agent.

According to an embodiment of the present invention, while the digested sludge generated in the biological treatment process is temporarily retained in the storage tank 25, the basic ferric sulfate, which is a coagulation aid for inhibiting scale formation, is added to the digested sludge at 500 to 4,000 mg / L And the step of adding 100 to 400 mg / L of the amount of the digested sludge to the cationic polymer flocculant is carried out after the step of injecting the coagulant aid.

According to one embodiment of the present invention, the coagulant aid is added to the digested sludge before the addition of the polymer flocculant, and the introduction of the polymer flocculant into the mixture of the digested sludge and the basic ferric sulfate, It is effective in suppressing byte generation.

That is, in the two-liquid dewatering system according to an embodiment of the present invention, the basic ferric sulfate, which is an aggregation aid, is added to the digested sludge before mixing with the polymer flocculant, and then the polymer flocculant is added in the next step.

3, ferric sulfate basic ferrous sulfate 51, which is a coagulation aid for scale formation inhibition, is added and mixed in the storage tank 25, and then the sludge mixed with the flocculant aid is blended with the polymer flocculant (52). Floc-reinforced drug mixed sludge by the coagulation assistant and polymer flocculant is transferred to the dewatering device (15) by the transfer pump and dehydrated.

On the other hand, in a facility without a storage tank, basic ferric sulfate can be directly introduced into the sludge transfer pipe.

The molecular formula of the basic ferric sulfate used as the coagulation assistant for inhibiting scale formation according to an embodiment of the present invention is as follows.

Fe 2 (OH) n (SO 4 ) 3-n / 2 (0 <n? 2)

The basic ferric sulfate according to one embodiment of the present invention is structurally composed of SO 4 of ferric sulfate 2 - part of OH is converted into OH - and OH group is polymerized as crosslinking to form a polynuclear complex.

Because of this, it has high cohesion ability and basicity, so it consumes less alkalinity and has less corrosiveness.

The iron-based coagulant conventionally used has generally high corrosion resistance, but the basic ferric sulfate according to one embodiment of the present invention is less corrosive than ferric chloride and has complete corrosion resistance in SUS.

[Table 1] shows that the basic ferric sulfate according to one embodiment of the present invention has the following characteristics.

Specific gravity (20 ℃) 1.4 to 1.6 pH (1 w / v%) 2 or more Total Fe over 10 Ferrous Fe 2+ 0.07% or less

Basic ferric sulfate is a phosphorus removal agent and has a basicity similar to basic aluminum chloride (PAC), which is widely used in water treatment facilities. Therefore, it is characterized by high cohesion and low causticity.

According to one embodiment of the present invention, digested sludge subjected to anaerobic digestion in a digester after biological primary treatment is a fine particle having surface charge of negative (-), so cationic (+) polymer is added to neutralize surface charge After the adsorption crosslinking is simultaneously carried out to coagulate the flocs, dehydration takes place.

When only the polymer flocculant is added to the digested sludge, the flocculation of the sludge microparticles is insufficient, so that the strength of the flocs is insufficient and the water content and viscosity of the dewatered cake can be formed.

In the dehydration process using the coagulant aid for inhibiting scale formation and the cationic polymer flocculant according to an embodiment of the present invention, Fe 3+ ions of basic ferric sulfate added prior to the polymer flocculant are adsorbed on the digested sludge particles, And the unreacted (-) charge is adsorbed on the digested sludge particles by the cationic polymer added afterward.

Accordingly, in the dehydration process using the coagulant aid for inhibiting scale formation and the cationic polymer flocculant according to an embodiment of the present invention, the crosslinking of the sludge particles proceeds at all times through the polymer chain, so that harder and stronger flocs can be formed.

In addition, in the dehydration process using the coagulant aid for inhibiting scale formation and the cationic polymer flocculant according to an embodiment of the present invention, the effect of removing phosphorus in the separated liquid and inhibiting the strobot (MAP) .

Techniques for removing phosphorus by adding iron salts or aluminum salts are generally well known. The soluble phosphate ion (PO 4 3- ) of the sludge reacts with the trivalent iron (Fe 3+ ) of basic ferric sulfate according to the embodiment of the present invention to generate a weakly soluble salt in the form of iron phosphate, And is fixed in the dehydrated cake.

Therefore, the sludge treatment water treatment using basic ferric sulfate according to an embodiment of the present invention has a large phosphorus removal effect.

PO 4 3 + Fe 3+ ? FePO 4 ↓

When basic ferric sulfate is added to digested sludge, the phosphorus in the sludge becomes insoluble phosphoric acid iron, and the concentration of soluble phosphorous is lowered, thereby inhibiting the production of stroby (MAP). In addition, the already generated strobyte (MAP) can be decomposed by increasing the solubility due to the pH drop.

Hereinafter, the characteristics of the ferric sulphate ferrous sulfate according to one embodiment of the present invention are tested.

In another experiment according to an embodiment of the present invention, in order to compare the characteristics of the addition of the polymer coagulant and the addition of the basic ferric sulfate, the basic ferric sulfate fermentation was performed at 500 mg / L, and the water content was measured by sampling at the maximum hydraulic pressure for each injection rate.

The polymer flocculant was injected constantly at 2.1 m3 / hr (1.2-1.7% / DS) using the current chemical (liquid, cationic, , And the experiment was carried out under the same conditions three times for each period.

form Hydraulic drive system Throughput 20 m3 / hr Revolutions 2,500rpm Vehicle speed 4 to 5 rpm Dehydration concentration 1.8 to 2.5%

In the experimental example according to one embodiment of the present invention, water content was measured at intervals of 10 to 30 minutes in a dehydrated cake sampling port of a centrifugal dehydrator, and repeatedly measured using an infrared moisture meter.

Polymer flocculant was added to the usual digested sludge sludge cake solids content (DS) 1.4% based on the as regardless of the addition or absence of a basic ferric sulfate, 15m 3 / h ~ 20m 3 / h polymer of 0.2% with respect to the digested sludge of the flocculant solution was 1.75m 3 / h, ~ 2.8m 3 / h was introduced.

The dehydrated and separated solution was collected at the same time as the dehydrated cake in the separating solution collection port of the centrifugal dehydrator, and the pH, T-P, T-Mg and S-Mg were analyzed. In addition, the odor measurement was made by measuring the concentration of hydrogen sulfide, methyl mercaptan, and ammonia through the gas detection tube at the upper inspection port of the conveying conveyance of the cake.

FIG. 4 shows the water content and the hydraulic pressure characteristics of the centrifugal dehydrator according to the input of basic ferric sulfate in an experimental example according to an embodiment of the present invention.

Table 3 shows the measurement results of the water content and the hydraulic pressure of the centrifugal dehydrator according to the input of the basic ferric sulfate in the experimental example according to one embodiment of the present invention.

division Basic ferric sulfate fermentation rate (mg / L) 0 1,000 1,500 2,000 2,500  Average hydraulic pressure (bar) 87 94 133 108 104 Average water content (%) 76.2  75.5 73.9 74.8 74.9

4 and Table 3, when only the polymer flocculant was added without adding basic ferric sulfate, the hydraulic pressure ranged from 72 to 87 bar, and the water content was 76.1 to 77.5%.

On the other hand, after the addition of basic ferric sulfate, the hydraulic pressure gradually increased with an increase in the addition rate, and the water content decreased.

As shown in FIG. 4, there is a linear relationship between the hydraulic pressure and the water content, and the water content is lowered by about 0.6% every time the hydraulic pressure is increased by 10 bar.

These results indicate that the mechanism of dehydration of basic ferric sulfate in a hydraulic centrifugal dehydrator is not based on the direct reduction of the water content by addition of basic ferric sulfate but by the addition of basic ferric sulfate, As a result, the solids retention time in the bowl is increased and the hydraulic pressure is increased, leading to a decrease in the water content.

[Table 3] shows that the highest hydraulic pressure was obtained when 1,500 mg / L of basic ferric sulfate was added, and the water content was decreased by 2.3% when compared with no addition.

On the other hand, the addition of more than 2,000 ~ 4000 mg / L reversed the hydraulic pressure. This is because the excess charge of basic ferric sulphate tilts the interface charge of the sludge to the positive (+) side, The coagulation effect is reduced.

In addition, it is analyzed that below 500 mg / L, no effect was observed compared to no addition of basic ferric sulfate.

Therefore, it can be seen that the preferable range of basic ferric sulfate to digested sludge has an effect on water content lowering in the range of 500 to 2,000 mg / L.

5 is a graph showing the relationship between total magnesium (T-Mg) and soluble magnesium (S-Mg) in a dehydration separation liquid in a dehydrator according to an embodiment of the present invention in a dehydrator according to the input of basic ferric sulfate will be.

Referring to FIG. 5, it can be seen that S-Mg increased as the addition rate of basic ferric sulfate was increased. This is the iron ion and react to form an iron phosphate due to Mg 2+ in less than one of Mg fails to be the reaction of the components of a straw-byte (MAP) solution remaining is formed from a straw-byte (MAP) in a conventional way .

In the case of adding 1,500 mg / L of basic ferric sulfate according to one embodiment of the present invention, S-Mg (soluble magnesium) is 21 mg / L, which exceeds the S-Mg concentration of 17 mg / L of digested sludge It is analyzed that the strobytes (MAP) already generated in the digested sludge have been dissolved.

In the experiment according to an embodiment of the present invention, when the soluble magnesium concentration in the dehydrated and separated liquid is 10 mg / L or more and the insoluble magnesium concentration which is the difference between the total magnesium concentration and the soluble magnesium concentration is 10 mg / L or less, Respectively.

Assuming that insoluble Mg, which is the difference between T-Mg and S-Mg, is the amount of Strobite (MAP), the amount of Strobite (MAP) .

According to one embodiment of the present invention, the addition rate of the basic ferric sulfate is preferably 1,000 to 2,000 mg / L to the digested sludge from the viewpoint of suppressing the production of the stroby (MAP).

The addition rate of the basic ferric sulfate is preferably 10 mg / L or more, more preferably 10 mg / L or more, and more preferably 10 mg / L or more, and the insoluble magnesium concentration, which is the difference between the total magnesium concentration and the soluble magnesium concentration, Scale control in the digested sludge pipe and dehydrated and separated liquid pipe can be made more economically and efficiently.

FIG. 6 shows an image obtained by comparing scale formation according to the input of basic ferric sulfate in an experimental example according to an embodiment of the present invention.

Fig. 6 (a) is a cross-sectional view of a sludge feed pipe of a centrifugal dehydrator not containing basic ferric sulfate after tube maintenance, FIG. 6 (b) is a view showing a cross section of an image of a pipe for use in a sludge supply pipe of a pneumatic dehydrator not containing basic ferric sulfate after tube maintenance, adding basic ferrite sulphate Lt; / RTI &gt; shows a cross-sectional view of the feed pipe for the same pneumatic dehydrator after 50 days.

Referring to FIG. 6, in the digested sludge transfer pipe before adding basic ferric sulfate, there was a difference in scale amount depending on the dehydrator, but a scale scale of about 20 to 60 mm was adhered as a whole. However, 50 days after the addition of the basic ferric sulfate, the piping was opened and confirmed. As a result, no scale attachment was observed in most of the piping.

FIG. 7 is a graph showing changes in the SS concentration of the dehydrated and separated water in the dehydrator according to the experimental example of the present invention, when the basic ferric sulfate was added.

7, the SS concentration of the dehydrated and separated liquid was 210 mg / L when basic ferric sulfate was not added, but decreased to 130 mg / L when basic ferric sulfate was added at 2,000 mg / L (About 40% removed).

In general, when the dehydrated cake layer in the bowl becomes thick and the compaction density of the dehydrated cake becomes high, the SS concentration of the separated liquid tends to increase, but when the basic ferric sulfate is added, the SS concentration is not adversely affected even when the hydraulic pressure is increased , Whereas the cleanliness of the separation liquid is improved.

In addition, when 2,500 mg / L of basic ferric sulfate was added, the SS concentration was rather increased, which is analyzed to be attributed to the fact that the coagulation effect of the polymer was lowered due to the effect of excessive addition as in the water content.

Based on the above results, the optimum addition rate of basic ferric sulfate is estimated to be in the range of 1,500 ~ 2,000 mg / L when water content and SS recovery are considered.

8 is a graph showing changes in the concentration of T-P in the dehydrated and separated solution in the dehydrator according to the experimental example of the present invention.

8, when the basic ferric sulfate was not added, the total phosphorus concentration (TP concentration) of the dehydrated and separated solution was high at a concentration of 102 to 121 mg / L in the dehydrated and separated solution, As the addition rate of iron was increased, it decreased stepwise, and when 1,500 mg / L was added, it decreased to 56 ~ 73 mg / L (about 45% removal).

In this reduced state, the T-P load applied to the sedimentation basin as reflux water is about 220 kg / day, which corresponds to about 0.36 ppm when converted to 600,000 m3 of daily average discharge. If the T-P load of the separation liquid is reduced by the addition of basic ferric sulfate, it can be understood that it can contribute to improvement of discharge water quality, reduction of phosphorus removal agent used in advanced treatment facilities and total phosphorus treatment facilities.

At the disposal site of sewage sludge, a lot of sulfur compound odor such as hydrogen sulfide and methyl mercaptan is generated. In addition, corrosion of concrete equipment by hydrogen sulfide can be another problem.

The Fe 3+ and Fe 2+ ions of basic ferric sulfate according to an embodiment of the present invention are characterized by having an effect as a deodorant because they are easy to react with sulfides.

The reaction between the basic ferric sulfate and the sulfide according to one embodiment of the present invention is as follows.

H 2 S + 2Fe 3+ ? S 0 ↓ + 2Fe 2+ + 2H +

H 2 S + Fe 2+ ? FeS ↓ + 2H +

In addition, when the pH is raised by the digestion treatment, ammonia is easily diffused in the digested sludge. However, when basic ferric sulfate according to one embodiment of the present invention is added, the pH is lowered due to the acid component, It is possible to suppress the dissipation.

NH 3 + H + - & gt ; NH 4 +

Table 4 shows the result of measurement of odor on a dehydrated cake conveying conveyor according to the experiment of the dehydration treatment of the two-component dehydrating solution according to one embodiment of the present invention.

division Basic ferric sulfate fermentation rate (mg / L) 0 1,000 1,500 2,000 2,500 Ammonia (ppm) 40 16 (60) 12 (70) 10 (75) 3 (93) Hydrogen sulfide (ppm) 0.2 ND ND ND ND Methyl mercaptan (ppm) ND ND ND ND ND

★ N.D: below detection limit, (): indicates removal rate

As shown in Table 4, when the basic ferric sulfate was not added, the ammonia concentration was 40 ppm, while the basic ferric sulfate was decreased to 3 to 16 ppm (removal rate 60 to 93%). It is analyzed that this is due to the pH drop of the sludge due to the addition of basic ferric sulfate.

For hydrogen sulfide, 0.2 ppm was detected when basic ferric sulfate was not added, but it fell below the detection limit when added. Methyl mercaptan was not detected even when no addition was made.

On the other hand, Tables 5 to 8 show the characteristics exhibited when 1,500 mg / L of basic ferric sulfate according to one embodiment of the present invention is added to a sewage treatment plant of another environment locally.

Table 5 shows the concentration of magnesium in dehydrated and separated water before and after the addition of basic ferric sulfate at the southwest wastewater treatment plant.

Centrifuge Unit 1 Centrifuge Unit 2 Union 1 Before addition After addition Before addition After addition Before addition After addition Total magnesium concentration ① 21.9 17.0 14.7 21.9 13.5 12.7 Soluble magnesium concentration ② 3.3 11.4 4.4 15.0 7.9 10.3 Insoluble magnesium concentration ①-② + 18.6 5.6 19.3 6.9 5.6 2.4

                                                                   (mg / L)

Table 6 shows the scale thickness (mm) characteristics generated in the sludge supply piping before and after the addition of basic ferric sulfate in the Seinam environment sewage treatment plant and the inner wall of the dehydrated separation liquid pipe.

Centrifuge Unit 1 Centrifuge Unit 2 Union 1 Before addition After addition Before addition After addition Before addition After addition Sludge supply piping 18 0 20 0 22 0 Dehydrated separation liquid piping 20 5 15 5 38 0

Table 7 shows the scale characteristics generated in the sludge supply piping and the dehydration separation liquid piping before and after the addition of the basic ferric sulfate in the southwest wastewater treatment plant.

Centrifuge Unit 1 Centrifuge Unit 2 Union 1 Before addition After addition Before addition After addition Before addition After addition Dehydrated separation liquid T-P 245 97.3 196 98.8 198 114

Table 8 shows the odor characteristics before and after the addition of basic ferric sulfate in the pre-centrifugal dehydrator stage at the Seinam environment sewage treatment plant (unit: ppm)

Centrifuge Unit 1 Centrifuge Unit 2 Union 1 Before addition After addition Before addition After addition Before addition After addition NH3 13 6.5 11.3 10 12.6 8.4

According to the dehydration dehydration method using basic ferric sulfate in the centrifugal dehydrator according to an embodiment of the present invention, the addition of basic ferric sulfate to the strobite (MAP) increases the concentration of S-Mg in the separated solution , It is possible to have a remarkable effect of inhibiting the strobyte.

As a result of comparing the dehydration dehydration method using basic ferric sulfate to a centrifugal dehydrator according to an embodiment of the present invention, when the polymer flocculant alone was administered, dehydration cake water content was 77.3%, and basic iron sulfate was 1,500 mg / L, the effect is reduced to 75.0% (2.3% decrease).

This is because the addition of basic ferric sulfate reduces the dehydration cake of about 9%, thus reducing the disposal cost of the dehydrated cake and reducing the cost of sewage treatment.

11; First settling basin
12: aeration tank
13: Second settler
14: digester
15: Dewatering device
16, 52: Coagulation drug dispenser
25: Digestion sludge reservoir
26: Mixer
42: Digestion sludge transfer pipe
51: Basic Ferric Sulphate Feeder

Claims (8)

A method for dewatering digested sludge generated in a biological sewage treatment process,
A step of injecting basic ferric sulfate to the digested sludge in a range of 500 to 4,000 mg / L;
A step of adding a polymer flocculant to the cationic polymer flocculant in a range of 100 to 400 mg / L after the step of adding the flocculant aid for inhibiting scale formation; And
Dewatering the sludge after the step of injecting the polymer flocculant by a dewatering device; A method for treating sewage sludge using a coagulation aid for scale formation inhibition
The method according to claim 1,
Wherein the coagulant auxiliary agent is added in an amount of 1,500 mg / L of basic ferric sulfate in the step of adding the flocculant aid.
The method according to claim 1,
Wherein the coagulant aid is introduced into a storage tank in which digested sludge can temporarily be stored between the digestion tank and the dewatering device and mixed with the extinguished sludge.
The method according to claim 1,
The basic ferric sulfate,
Characterized in that it comprises the characteristics of a specific gravity (at 20 ° C) of 1.4 to 1.6, a pH of 2 or more, a total-Fe of 10% or more, and a ferrous Fe 2 + of 0.07% or less Way
The method according to claim 1,
Characterized in that the basic ferric sulfate is formed by the following molecular formula: Sulfur sludge treatment method using coagulation assistant for inhibiting scale formation
Fe 2 (OH) n (SO 4 ) 3-n / 2 (0 <n? 2)
The method according to claim 1,
The basic ferric sulfate,
SO 4 of ferric sulfate A portion of 2- OH - form a three-dimensional coordinate sewn transferred to a sewage sludge treatment method, it characterized in that the polymerization is OH group as a cross-link the polynuclear complexes
The method according to claim 1,
Wherein the basic ferric sulfate is added in an amount such that the concentration of the soluble magnesium in the dewatered separation liquid generated in the dewatering apparatus is 10 mg / L or more. The method according to claim 1, Way
The method according to claim 1,
Wherein the amount of the basic ferric sulfate to be added is in a range such that the concentration of insoluble magnesium, which is the difference between the total magnesium concentration and the soluble magnesium concentration in the dehydrated separation liquid generated in the dehydration apparatus, is 10 mg / L or less Sewage sludge treatment method using coagulant aid
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106746477A (en) * 2016-12-13 2017-05-31 北京城市排水集团有限责任公司 A kind of urban wastewater treatment firm Treatment of Sludge and resource utilization method
CN113880263A (en) * 2020-07-02 2022-01-04 中国石油化工股份有限公司 Modified sewage induced scaling device and treatment method

Families Citing this family (1)

* Cited by examiner, † Cited by third party
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KR102320633B1 (en) * 2015-05-19 2021-11-02 (주) 폴리테츠코리아 System for treating sewage sludge using adjuvant flocculants for scale preventer

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100573186B1 (en) 2004-06-30 2006-04-24 한국남부발전 주식회사 Wastewater Disposal Method in Flue Gas Desulfurization System by Using Scale Preventer
KR20090051450A (en) * 2007-11-19 2009-05-22 강우식 The treatment method of high concentrated organic waste water,like with leachate of food waste water and animal waste water

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100573186B1 (en) 2004-06-30 2006-04-24 한국남부발전 주식회사 Wastewater Disposal Method in Flue Gas Desulfurization System by Using Scale Preventer
KR20090051450A (en) * 2007-11-19 2009-05-22 강우식 The treatment method of high concentrated organic waste water,like with leachate of food waste water and animal waste water

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106746477A (en) * 2016-12-13 2017-05-31 北京城市排水集团有限责任公司 A kind of urban wastewater treatment firm Treatment of Sludge and resource utilization method
CN106746477B (en) * 2016-12-13 2019-06-25 北京城市排水集团有限责任公司 A kind of processing of urban sewage treatment plant sludge and resource utilization method
CN113880263A (en) * 2020-07-02 2022-01-04 中国石油化工股份有限公司 Modified sewage induced scaling device and treatment method

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