瑞典专利SE1200050A1 Sludge treatment method

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专利摘要:
The invention relates to a method for treating acidified chemical sludge from water and sewage treatment plants where said sludge (feed) is pumped to one or a series of parallel micro- or ultra-filtration plants where a permeate and a concentrate are obtained. The method is designed so that the feed is continuously supplied to the plant. In one embodiment, pure water is continuously supplied to the at least second and subsequent micro- or ultra-filtration plants. In a further embodiment, the amount of diawater added is equal to the amount of permeate or feed. 6/7 16
公开号:SE1200050A1
申请号:SE1200050
申请日:2012-01-24
公开日:2013-07-25
发明作者:Johnny Olsen
申请人:Johnny Olsen；
IPC主号:

专利说明:

has been separated.
One method of separating aluminum and iron from chemical sludge is to acidify the sludge in a first step, for example with sulfuric acid. This dissolves the metal hydroxide precipitate and free metal ions are formed.
At the same time, entrapped and adsorbed suspended and organic substances are released in the hydroxide precipitate. In a second step, the acidified sludge, the feed, is micro- or ultra-filtered. A circulation pump pumps / circulates the sludge in a loop, at high speed through membrane channels, whereby a permeate and a concentrate remaining in the loop take place. The membranes can advantageously be made of ceramic material, as these, due to their hardness, are more resistant to mechanical abrasion and have a better chemical resistance than, for example, polymeric membranes. The separated permeate will mainly contain the liberated metal ions, ie the precipitating chemical as well as minor organic compounds, while the remaining concentrate contains suspended solids and major organic compounds. Depending on the retention of impurities, the permeate can thus replace the precipitating chemical. The flux, ie liters of perneat produced per square meter of membrane area and hour, is temperature dependent. If the other parameters are constant, a higher temperature gives a higher ﬂ ux and vice versa. This is mainly due to the fact that the viscosity of the membrane-filtered sludge decreases with increasing temperature. The content of dissolved metal salt has a negligible effect on the viscosity. In order to minimize the membrane surface, and thus also the energy consumption (circulation pump power), it is therefore an advantage to maintain a high operating temperature during membrane filtration. If ceramic membranes are used, the temperature in the loops can be allowed to exceed 100 C, but this requires that the system pressure is higher than the vapor pressure to avoid boiling. However, operating temperatures above 100 C, and the consequent high operating pressures, can make the system more expensive because you have to choose materials that are corrosion resistant at high salinities and low pH. The cost of acid, if cheap residual acid is not available, and the energy cost of operating the circulation pumps are the diaphragm system's largest operating cost items. However, the energy supplied to the circulation pump is converted into heat in the circulated sludge. In order to achieve and maintain a high temperature during the membrane filtration, the heat is utilized by exchanging friends. Heat exchange can, for example, take place between cold media, such as incoming sludge and slide water, and hotter such as outgoing pennea and concentrate.
An object of the invention is therefore to provide a method for treating sludge which allows continuous treatment of the sludge.
These and other objects are achieved by a method of treating sludge according to the core features of the independent claim.
Summary of the invention The invention relates to a method for treating acidified chemical sludge from water and sewage treatment plants where said sludge (feed) is pumped to one or a series of parallel micro- or ultra-filtration plants where a permeate and a concentrate are obtained. The method is advantageously designed so that the feed is continuously supplied to the plant (s).
In a particularly troublesome embodiment, pure water is continuously supplied to the at least second and subsequent micro- or ultra-filtration plants. In a further advantageous embodiment, the amount of diawater added is equal to the amount of penneate or feed.
Brief description of the figures Fig. 1 shows device according to prior art Figs. Fig. 2 shows a first embodiment of a device according to the invention. Fig. 3 shows the heat balance in the first embodiment. Fig. 4 shows a second embodiment of a device according to the invention. Fig. 5 shows the heat balance in the second embodiment. Fig. 6 shows a third embodiment of a device. according to the invention Fig. 7 shows the heat balance in the third form of desiccation. Description of preferred embodiments In a patented method (Swedish patent EP 03728208.4) a batchwise membrane alteration of the acidified sludge according to Figure 1 and the following description is described. Sludge (1) is led to a reaction tank 3 (2). An acid (3), for example sulfuric acid, is also led to this reaction tank. Sludge and acid are mixed using a stirrer (4). The mixture (feed) is pumped with a feed pump (5) through a first (6) and then a second (13) heat exchanger to a working tank (7). A circulation pump (8) pumps the sludge through a membrane (9) in a loop (10) in return to the working tank. A permeate (1 L) is discharged from the membranes. The permeate heated by the circulation pump is heat exchanged (6) with incoming cold acidified sludge, and then reused as a precipitating chemical. When a maximum TS content has been reached in the working tank, it is emptied of the resulting concentrate (12), possibly after washing the slurry with clean water (filtration). When the working tank is refilled, the collected hot concentrate (13) is exchanged with cold incoming sludge and membrane filtration of a new batch can be started. To increase the recycling rate, metal ions can be washed out of the sludge by so-called filtration. When a maximum TS content has been reached in the working tank, the feed is replaced with clean water (slide water). When as much slide water has been added as the remaining volume in the working tank before filtration and as much has been produced as perrneat, a 1: 1 filtration has been made. By this process, 50% of the metal ions remaining in the concentrate have been washed out.
The present invention relates, in contrast to the batch process described above, to a continuous process for membrane filtration of surgical sludge, as defined in Figures 2, 4 and 6 with the accompanying descriptions. The advantage of a continuous system is that perrneat, concentrate and di-filtrate are produced without interruption for filtration, emptying of concentrate and filling of surgical sludge. Another advantage is that no working tank is included in the system. It should be pointed out that both batch and continuous systems require dxift stops when washing the membranes.
Both the waterworks and the effluent can contain finely divided suspended particles.
The particles can be present in the raw or wastewater, but can also be added with the precipitation chemical if this contains undissolved particles. These particles, for example silicon sand or aluminum carbide, have a blasting effect on the membrane as they are pumped in with the sludge and through the membrane channels at high speed. Due to the abrasion effect that occurs, the active membrane layer is damaged and the life of the membrane is shortened. Separating these incoming particles by sieving is a problem, as other small, non-abrasive suspended substances in the sludge can easily block the filter. This gives rise to the fact that it often needs to be backwashed with filtered or clean water, which increases the loss of recyclable precipitating chemical. What distinguishes the abrasive particles from others is that the former o ﬁ ast have a high density and can therefore be easily separated in a hydrocyclone. The present invention, which is illustrated in Figures 2, 3 and 4, therefore relates to an installation of one or more, in series or in parallel hydrocyclones through which the acidified sludge to the MF or UF plant is pumped and where heavier particles are separated. Hydrocyclones are dimensioned according to the speed of fate through the cyclone, which means that they require a constant fate to provide optimal separation. This means that a continuous system with a constant feed flow is preferable to a bachwise system, where the flow decreases with increasing TS content in the working tank and thus reduced ﬂ ux. The concentrate from the hydrocyclone or hydrocyclones, which contains a mixture of acidified sludge and of separated particles, is discharged to a sedimentation tank. In this tank, a second separation of heavier particles takes place which is pumped to and mixed with outgoing concentrate from the membrane plant. The particulate sludge is returned to the reaction vessel. The introduction of a sedimentation tank into the process increases the concentration of particles in the concentrate from the hydrocyclone and thus reduces the losses of recyclable precipitation chemical.
An embodiment of a continuous system is illustrated in Figure 2. According to the figure, sludge (1) is led to a reaction tank (2). An acid (3), for example sulfuric acid, is also led to this reaction tank. Sludge and acid are mixed using a stirrer (4). The mixture is pumped with a feed pump (5) through a heat exchanger (6) to a hydocyclone. In this, high-density solid particles are separated. A partial stream (8) of a mixture of particles and sludge is diverted from the hydrocyclone.
This substream is led to a sedimentation tank (9) where a concentrate of solid particles is pumped (10) to and mixed with the output concentrate ﬁ from the membrane plant. The sludge phase (11) ﬁ from the sedimentation tank, freed from heavier particles, is led to the reaction tank. The sludge phase from the hydrocyclone is led to a circulation pump (12) which pumps the sludge through membrane (13) and in a loop (14) in return to the circulation pump. A permeate (15) is diverted from the membranes. The perneat heated by the circulation pump is heat exchanged (6) with incoming cold acidified sludge and then reused as a precipitating chemical. From the loop a concentrate (16) is diverted which is mixed with the concentrate of solid particles from the sedimentation tank. The mixture can then be neutralized and dewatered. Even if the retention of the metal ions is assumed to be zero during the membrane filtration, the concentrate will always contain the same metal ion content as the feed, regardless of whether it is a batch or continuous system. At a VRF (Volume Reduction Factor) of 10, ie 9/10 of the feed will consist of permeate and 1/10 of concentrate, the recovery of metal ions will be 90%.
Table 1 below shows exemplary embodiments according to Figure 2, where a 2% acidified sludge is used as feed. At this TS content in the feed, it is assumed that the TS content in the outgoing concentrate is 10% at a VRF of 10. Furthermore, it is assumed that the retention of metal ions, in this case Al, is 0. As shown in the table, the recovery rate of metal ions is 90 %.
Table 1.
Incoming sludge Permeat Concentrate Flow m3 / h 10 9 1 TS% 2 10 Al content mg / l 3,000 3,000 3,000 Mass ﬂ desolate kg Al / h 30 27 3 The energy consumption of the circulation pump is about 10 kW / m3 produced perneat at a ﬂ ux of 100 l / m2, hrs. To achieve this ﬂ ux, given that the TS content in the outgoing concentrate is about 10%, a dri ﬂ temperature of 70-90 C is usually required. According to the heat balance, see ﬁ figure 3, this temperature can be achieved by heat exchange between hot outgoing penneat and incoming cold surgiort sludge.
Fig. 3 shows the heat balance in the first embodiment, where the input is indicated by a slanted box to facilitate understanding. For the device, the energy in is 98kW while the energy out is 97kW. The device also applies to 100l / m2h, l0m3 / h, 100m2, 0.53m2 / rod, 189 rods, 7.6m3 / h, rod, l434m3 / h, 1.5bar pressure drop, 60% efficiency and 98kW.
If you choose to instead use 1% sludge as feed and a VRF of 20, the recovery increases from 90 to 95%, according to what is shown in Table 2. At the same time, the amount of permeate more than doubles. The increased production of permeate means that the membrane surface, and thus pump energy supplied, must more than double, which from an investment and operating cost point of view cannot justify a 5% increase in the recycling rate.
Table 2.
Incoming sludge Permeat Concentrate Flow m3 / h 20 19 1 TS% 1 10 Al content mg / l 1,500 1,500 1,500 Mass ﬂ desolate kg Al / h 30 28.5 1.5 A second embodiment of a continuous system is shown in Figure 4 where the feed is a 2% sludge. According to ﬁ guren, sludge (1) is led to a reaction tank (2). An acid (3), for example sulfuric acid, is also led to this reaction tank. Sludge and acid are mixed using a stirrer (4).
The mixture is pumped with a feed pump (5) through a friend exchanger (6) to a hydocyclone. In the hydocyclone, high density solid particles are separated. A partial stream (8) of a mixture of particles and sludge is diverted from the hydrocyclone. This substream is led to a sedimentation tank (9) where a concentrate of solid particles is pumped (10) to and mixed with the output concentrate from the membrane plant. The sludge phase (11) from the sedimentation tank, freed from heavier particles, is led to the reaction vessel. The sludge phase from the hydrocyclone is led to a circulation pump (12) which pumps the slurry through membrane (13) in a loop (14) in return to the circulation pump. A permeate (15) is diverted from the membranes. A concentrate (16) is diverted from the loop which forms the feed for the next and last loop. The feed is led to a circulation pump (17) at the same time as slide water (18) is supplied. Feed and slide water are pumped through diaphragm (19) in a loop (20) in return to the circulation pump. From the membranes is derived a permeate (21) which is mixed with the permeate ﬁ- from the first loop. The permeate from the first loop is exchanged (6) with incoming cold acidified sludge and then mixed with that from the second loop if the mixture is reused as a scavenging chemical. In cases where a temperature> 100 C is desired in the loops, all pemreat can be heat exchanged. In the same way, part or all of the hot concentrate (22) from the second loop can be heat exchanged (23) with cold incoming slide water. This cold concentrate is mixed with the concentrate of solid particles from the sedimentation tank. The mixture of concentrate can then be neutralized and dewatered.
Table 3 below shows exemplary examples according to Figure 4 where a 2% acidified sludge is used as feed. At a VRF of 10, the concentrate is passed from the first loop to a second loop. In the second loop, the metal ions are washed out of the concentrate by filtration. In the exemplary embodiment, slide water is added in the same amount as the added concentrate ﬁ ° from the first loop (1: 1 filtration). Furthermore, it is assumed that the retention of metal ions, in this case Al, is 0 in all loops. The residual amount of metal ions in the outgoing concentrate will thus be reduced by 50%, provided that as much permeate as the added amount of diawater is produced. With the addition of this second loop with filtration, the recovery rate has increased by 5% to 95% while the total membrane surface, provided that the är is the same, and the pump energy consumption has only increased by just over 10%.
Table 3 Loop 1 Ink sludge Perrneat Concentrate Flow m3 / h 10 9 1 TS% 2 Al content mg / l 3,000 3,000 3,000 Mass kg kg kg Al / h 30 27 3 Loop 2 Feed Diawater Permeat Concentrate Flow m3 / h 1 1 1 1 TS% 10 Al content mg / I 3,000 O 1,500 1,500 Mass ﬂ desolate kg Al / h 30 0 1,5 1,5 The energy consumption of circulating pumps is about 10 kW / m3 produced permeate at a ﬂ ux of 100 1 / m2, h. To achieve this ﬂ ux, given that the TS content in the outgoing concentrate is about 10%, an operating temperature of 70-90 C is usually required. According to the heat balance in ﬁ gur 5, this temperature can be achieved by heat exchange between hot outgoing permeate and incoming cold acidified sludge respectively diavatten.
Fig. 5 shows the heat balance in the second embodiment, where the input is indicated by an oblique box to facilitate understanding. For the device, the energy in is l07kW while the energy out is l07kW. The device also applies to 100l / m2h, l0m3 / h, 100m2, 0.53m2 / rod, 189 rods, 7.6m3 / h, rod, l434m3 / h, 1.5bar pressure drop, 60% efficiency and 98kW.
In a continuous system, according to what the exemplary embodiment in Figure 6 shows, it is advantageous to use tation-thickened or mechanically dewatered acidified chemical sludge as feed. The patented method only refers to the treatment of thin sludge, for example sludge from sedimentation or ﬂ otation. According to ﬁ guren, sludge (1) is led to a reaction tank (2). An acid (3), for example sulfuric acid, is also led to this reaction tank. Sludge and acid are mixed using a stirrer (4).
The mixture is pumped with a feed pump (5) through a heat exchanger (6) to a hydocyclone (7).
Before the hydrocyclone, slide water (12) is added. In the hydocyclone, high density solid particles are separated. A partial stream (8) of a mixture of particles and sludge is diverted from the hydrocyclone.
This partial stream is led to a sedimentation tank (9) where a concentrate of solid particles is pumped (10) to and mixed with output concentrate from the membrane plant. The sludge phase (1 1) ﬁ from the sedimentation tank, freed from heavier particles, is led to the reaction tank. The sludge phase ﬁ ° from the hydrocyclone is led to a circulation pump (13) which pumps the sludge through membrane (14) in a loop (15) in return to the circulation pump. A perennial (16) is diverted from the membranes. From the loop a concentrate (17) is diverted which forms the feed to the second loop. The feed is led to a circulation pump (18) to which also slide water (12) is supplied. The mixture is pumped through diaphragm (19) in a loop (20) in return to the circulation pump. From the membranes is derived a permeate (21) which is mixed with the permeate ﬁ from the first loop. From this second loop a concentrate (22) is derived which forms the feed to the third and last loop. The feed is led to a circulation pump (23) to which also slide water (12) is supplied. the mixture is pumped through diaphragm (24) in a loop (25) in return to the circulation pump. From the membranes a permeate (26) is diverted which is mixed with the permeate from the first and second loops. The mixture of hot perneat is heat exchanged (27) with incoming cold dia water and then reused as a precipitating chemical. From the third and last loop a hot concentrate (28) is diverted which is mixed with the concentrate of solid particles from the sedimentation tank. The mixture of concentrate can then be neutralized and dewatered or led to digestion. In case the incoming acidified sludge is not sufficiently watered so that an acceptably high temperature can be maintained in the membrane plant, the used concentrate can be heat exchanged (6) with cold incoming acidified sludge.
Table 4 below shows exemplary embodiments according to Figure 6 where a 20% dehydrated and acidified sludge is used as feed. 1: 1 dialing takes place in 3 consecutive steps. As in previous examples, it is assumed that the retention of metal ions, in this case Al, is 0 in all loops. Compared with the example in ﬁ gur 2, the recycling rate has decreased by 2.5% and with the example in ﬁ gur 4 by 7.5%. Assuming that the ﬂ ox is the same, the total membrane surface and thus also the pump energy consumption has decreased by more 60%. The lower recovery rate can be compensated by adding additional filtering steps, but whether this is justified from an investment and operational point of view can be assessed on a case-by-case basis.
Table 4 Loon 1 Feed Diawater Permeate Concentrate Flow m3 / h 1 l 1 1 TS% 20 Al content mg / l 30,000 0 15,000 15,000 Mass kg kg kg Al / h 30 0 15 15 Loop 2 Feed Diawater Permeat Concentrate Flow m3 / h 1 1 1 1 TS% Al content mg / l 15,000 0 7,500 7,500 10 Mass kg kg kg Al / h 15 0 7.5 7,5 Loop 3 Feed Diawater Permeate Concentrate Flow m3 / h 1 1 1 l TS% 10 A1 content mg / 1 7,500 0 3,750 3,750 Mass ﬂ kg kg Al / h 7.5 0 3.75 3.75 The energy consumption of the circulating pumps is about 10 kW / m3 produced permeate at a ﬂ ux of 100 l / m2, h. To achieve this x ux, given that the TS content in the outgoing concentrate is about 10%, an operating temperature of 70-90 C is usually required. According to the friend balance in ﬁ gur 7, this temperature can be achieved by heat exchange between hot outgoing hot and incoming cold dia water.
This presupposes that the incoming sludge has a temperature of> 60 C.
Fig. 7 shows the heat balance in the third embodiment, where the input is indicated by a slanted box to facilitate understanding. For the device, the energy in is 29.3kW while the energy out is 29.3kW. The device also applies l00l / m2h, 1m3 / h, l00m2, 0.53m2 / rod, 18.9 rods, 7.6m3 / h, rod, 143m3 / h, 1.5 bar pressure drop, 60% efficiency and 9.77kW.
Acidification of the dewatered sludge in the working example according to Figure 6 is preferably done with concentrated sulfuric acid. With the addition of acid, an exothermic reaction takes place which leads to an increase in the temperature of the sludge. Provided that the metal hydroxide content of the sludge is sufficiently high, no further temperature increase of the feed is required to obtain a temperature in the loops of 70-80 C, as shown in Figure 7. The latter can take place provided that the heat generated by the circulation pumps is recovered by heat exchange between incoming diawater and outgoing penneate. To obtain an efficient transfer of heat between the cold and hot medium, plate heat exchangers are often used. These have an efficient heat transfer and are cost-effective. In the cases reported in Figures 1, 2 and 4, the problem is that coatings quickly form on the slab surfaces that are in contact with sludge, which causes a deteriorated heat transfer. ll A poorer heat transfer, ie a high energy loss, means that the heat energy supplied via the circulation pumps is not sufficient to maintain a high temperature in the circulation loops. This in turn causes the viscosity of the circulating sludge to increase and the min to decrease. The increasing viscosity also means that it becomes significantly much more difficult to maintain a high TS content in the outgoing concentrate. The latter will lead to a reduced VRF and thus a lower metal recycling rate. The advantage of the present invention according to exemplary embodiment Figure 6 is that pure water is heat exchanged with a completely suspension-free peneate. This reduces the risk of coatings forming on the heat exchanger surfaces, which causes impaired heat transfer. Any cleaning of the heat exchanger is also limited to only the surfaces affected by the permeate. Cleaning of these surfaces can then take place in connection with washing the membranes. During membrane washing, the perennial that is passed over the heat exchanger surface will contain washing liquid. An additional advantage of the process is that the heat in the outgoing concentrate does not need to be utilized, which means that hot concentrate, or neutralization and without heating, can be led to a tiny digestion process. If dilute sulfuric acid is used and / or when the hydroxide content is too low, the acidified sludge may need to be aggravated, for example with direct steam or by heat exchange with outgoing hot concentrate.
At the low pH and the elevated temperature prevailing in the membrane process, it occurs, among other things, that carbon dioxide is formed by hydrolysis of organic substances in the sludge. If the pressure in the membrane system is low, the carbon dioxide formed can be released and create gas bubbles in the sludge.
These bubbles can in turn cause cavitation in the circulation pumps, which means that the flow through the membranes decreases or stops completely. This results in a rapid clogging of the membranes. In the present invention, therefore, the basic pressure in the membrane system must always be so high that carbon dioxide cannot be released. The basic pressure in each series of diaphragm filtration loops is maintained with the pressure from the feed pump and can be controlled, for example, by a pressure holding valve located on the outgoing concentrate line from the last stage.
The permeate from micro- or ultra-filtration of acidified sludge cannot be reused for purification of drinking water without further purification. An advantage of the invention is therefore that, for example, dewatered waterworks sludge can be transported to a sewage treatment plant where the precipitating chemical can be recovered and reused. Wastewater usually contains smaller and easily soluble organic compounds that cannot be precipitated with iron or aluminum salts. In cases where these create an unacceptably high residual content of TOC, Fenton's reaction can be used to purify the wastewater. Fenton is an oxidation process in which the pH of the wastewater is adjusted to 3-4 and a divalent iron salt is added in combination with hydrogen peroxide. Organic substances in the water will be oxidized to carbon dioxide and water. When the water is subsequently neutralized, the iron ions, which during the process have been oxidized to trivalent, will precipitate as iron (3) hydroxide. According to the present invention, the separated iron sludge, which usually contains non-oxidized and precipitated suspended solids, is treated in the same way as hitherto described. it is acidified and membranes are filtered. If an excess of acid and temperatures> 100 C are used in the system, the recycled iron in the permeate will have been reduced to divalent. Thus, the permeate can be reused in the Fenton reaction and reduce the need for both pure acid and iron (2) salt.
In the paper and cellulose industry, it is common for sludges from pre-sedimentation of wastewater to contain both calcium carbonate and ﬁ brer. In the present invention, this sludge is mixed with acidic concentrate from the membrane plant. This means that the calcium carbonate completely or partially neutralizes the concentrate. The gypsum formed during neutralization, in combination with fibers, makes the mixture very easy to drain. 13

权利要求:
Claims (13)
[1]
Claim 1 A method for treating acidified chemical sludge from water and sewage treatment plants where said sludge (feed) is pumped to one or a series of parallel micro- or ultra-filtration plants where a permeate and a concentrate are obtained, characterized in that the feed is continuously supplied to the plant / the facilities.
[2]
A method according to claim 1, characterized in that in at least second and subsequent micro- or ultra-filtration plants, clean water (slide water) is continuously supplied.
[3]
A method according to claim 1, characterized in that the amount of diawater added is equal to the amount of perrneat or feed.
[4]
A method according to claim 1, characterized in that pre-thickened and / or mechanically dewatered and subsequently acidified chemical sludge with a TS content> 6% is used as feed.
[5]
A method according to claim 1, characterized in that the feed to the membrane plants is pumped through one or ﬂ era, in series or parallel hydrocyclones.
[6]
A method according to claim 5, characterized in that the concentrate from the hydrocyclone or hydrocyclones, which contains a mixture of surgically sludge and separated particles, is continuously discharged, or intermittently, to a sedimentation tank.
[7]
A method according to claim 6, characterized in that in the sedimentation tank a second separation of heavier particles takes place which are pumped to and mixed with outgoing concentrate from the membrane plant and that the particle-free sludge is led back to the reaction vessel where acidification of the sludge takes place.
[8]
A method according to claim 8, characterized in that all or parts of the warmer permeate are heat exchanged with the colder incoming diawater.
[9]
A method according to claim 4, characterized in that the chemical sludge is pre-thickened and / or dewatered to such an extent that the amount of hydroxide in the sludge causes the exothermic reaction which occurs when acidifying the sludge with concentrated sulfuric acid to give a heat increase of 14> 30 ° C.
[10]
A method according to claim 1, characterized in that the concentrate is neutralized with sludge containing carbonate and fibers.
[11]
A method according to claim 4, characterized in that dewatered sludge is transported to sewage plants where the precipitating chemical is recycled and reused.
[12]
A method according to claim 1, characterized in that the sludge is derived from treatment of wastewater with a Fenton reaction.
[13]
A method according to claim 12, characterized in that an excess of acid is used in the acidification of the sludge 14. A method according to claim 12, characterized in that the temperature of the membrane filtration of the acidified sludge is> 100 C. A method according to claim 1, characterized by that the feed pressure is always so high that CO2 does not ﬁ figure. 15

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同族专利:

公开号 | 公开日

SE536317C2|2013-08-20|

引用文献:

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法律状态:

优先权:

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SE1200050A|SE536317C2|2012-01-24|2012-01-24|Sludge treatment method|SE1200050A| SE536317C2|2012-01-24|2012-01-24|Sludge treatment method|

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