DE4427478A1 - Process and plant for treating salt brine - Google Patents

Abstract

The invention relates to a process for treating salt brine, containing common salt, resulting from the pickling of vegetables, in particular sauerkraut, which is characterised in that - in a preliminary stage, preferably immediately following the said initial stage, the particles of suspended matter, cloud (haze)-forming substances and/or fibrous materials - together with microorganisms or microorganism agglomerates adhering thereto or deposited thereon - and if appropriate high-molecular-weight organic compounds are separated and removed, for example by gravity separation, in particular by centrifugation or filtration, from the brine which is considerably diluted by the removal of water from the fresh vegetable resulting from the salt treatment, in that, if appropriate after passing through an intermediate stage with intermediate storage, intermediate purification or the like, in addition - in a main stage the salt concentration of 1-3.5% by mass, in particular 1.5-2.5% by mass, is decreased in at least some of the brine itself, pretreated and stabilised in such a manner, or in an auxiliary solution made to interact with the same, to values permitted for discharge to the environment, in particular to values below 0.2% by mass ("diluate"), the salt concentration in the remaining portion of the brine or in an auxiliary solution (without addition of fresh salt) [lacuna] to at most 30% by mass, preferably to 5-10% by mass, in particular to 7-8... Original abstract incomplete.

Description

The invention relates to methods and systems for environmental right treatment or further treatment of saline brine, such as it arises when preparing pickled vegetables, especially sauerkraut. In a basic stage, the fresh cabbage or another fresh vegetable in chopped, especially cut, form with table salt (approx. 2 % By mass, based on vegetable mass) intimately mixed, and after each The specified exposure time of a maximum of a few days is at least one Most of the excess fresh brine that forms is salted Cut vegetables separately and should, especially from the standpoint of Environmental protection, in any case a further treatment or recycling leads.

It is obvious that in sauerkraut production Large producers very large amounts - about a third of the herb mass on fresh or press sheets, which are due to their high proportions (about 2-5 % By mass) of organic substances and especially as a result of the large quantities (about 2-3% by mass) of NaCl if not properly disposed of represent significant environmental pollution.

Previously known disposal concepts are essentially based on a microbiological, aerobic and / or anaerobic decomposition of the organic components in order to reduce the high COD values of the brine. In the case of sauerkraut brine, however, these processes have the following disadvantages:
The salt is not mined and pollutes the sewage treatment plant including the pipe systems and ultimately the environment. Furthermore, the ingredients of the herb water, which can be recycled or reused as long as the herb water is not spoiled by putrefaction processes, are not used in the aerobic processes. The organic fraction is broken down (at least methane is produced in the anaerobic process, which is used in-house) and the minerals end up in the waste water.

In addition to table salt, sauerkraut waste water contains carbohydrates and milk acid, protein compounds, vitamin C and undissolved substances. For a long time Reduction processes leave sulfur compounds and others volatile, organic sulfur compounds formed that are extremely unpleasant smell.

The practice so far, simply put the herb water back on the fields to discharge (here the high NaCl content is a problem), or to use it directly as waste water to discharge the receiving water (here the organic ingredients and the resulting high COD values) will be used by the authorities in the near future  different countries are no longer tolerated, or is already illegal. Direct discharge into municipal wastewater treatment plants is also not possible expedient. The high COD values of the herb water, for example, would only be enough To interpret the herb campaign for about 3 months Sewage treatment plant of a village for the equivalents of a small town make such a thing. In addition, the herb water has a very corrosive effect on the pipe systems and sewage treatment plants commonly used building materials.

It should also be mentioned here that EP-A1 0 456 368 Reinstatement of Lake, which comes from preserving cucumbers for conservation of a new batch has become known. With the concrete Realization of the very low concentrations of Preservative solutions of table salt of 2% in the presence of Acetic or lactic acid. Essentially there should be two Months of preservation can only be achieved by pickling their cucumbers keep fresh color and firmness even in hot climates real salting is not provided there. That after the preservation period withdrawn solution is opened again after merely adding loss-compensating salt brought the original, low concentration in itself and for a new one Batch used.

All concrete experiments on the method according to EP-A1 affect only use of low NaCl concentration cook salt-acid solutions. The mention of 15% NaCl as the upper limit is only hypothe table character, which results in particular from the fact that this EP-A1 with the problem of the enormous increase in the amount of liquid in a recycling Real salting sheets not remotely busy because of it was not recognized due to the completely different conditions or could be. There is therefore no information and no approach to Solution to this quantity and thus disposal problem.

The problem of solving sauerkraut by salting is explained by way of example:
When salting sauerkraut, when using about 25% NaCl solution, about 16% of the salt remains in the herb and the remaining about 8-9% salt amount forms after salting and stripping together with the amount of water used and the amount of water extracted from the fresh herb itself a brine with a salt concentration of only about 2.5%; a concentration which, incidentally, should have brine used in the process according to EP-A1 for the preservation of the fresh cucumber. With only one return of the fresh lake to the salting in sauerkraut, a quantity of water has to be mastered which corresponds to about four times the amount of water used in the first salting. The exponential increase in the amount of liquid after repeated recycling, which can be deduced solely from this initial situation, shows that it only takes a few cycles to make the problem of the amount of liquid to be treated completely uncontrollable.

The invention goes nowhere closer, among other things treated fact and knowledge of the "rapid" dilution and volume increase, and it has set itself the task of being economical sensible, fully in line with the recycling principle and ecological specify an acceptable way to control these volumes.

The aim of the invention is in particular one possible environmentally friendly disposal and, if necessary, use of the Press liquor resulting waters, wastewater, sludges, salts and organic sub punch, whereby, in particular due to the low prices for Sour vegetables, particularly complex process steps and procedures must be avoided. Also a burden of odor in the Near the facilities, e.g. B. as a result of undesirable fermentation processes as Sequence of necessary intermediate storage to compensate for intermittent Accumulation of the press sheet, especially in the high season, should occur be prevented.

According to the present invention, these objectives are largely avoided while avoiding the disadvantages mentioned with a new process for the treatment or further treatment of brine containing saline, in particular fresh brine, from the preparation of pickled vegetables, in particular sauerkraut, in which fresh vegetables, in particular, are used in a basic stage Fresh cabbage, in chopped, in particular cut, form is mixed with saline solution and, after each predetermined exposure time, at least a large part of the brine formed is separated from the vegetables treated with it, in particular cabbage, and used for further use, at least a part of the Completion of the basic stage separated or squeezed brine with compensating addition of the amount of table salt corresponding to the amount taken up by the vegetables is recycled into a table salt treatment of fresh vegetables, in particular cabbage, which is characterized in that each other Coordinated networking of the individual process steps together with recycling of the common salt, environmentally friendly desalination or demineralization of the liquid phase to be extracted from the brine with simultaneous environmentally friendly recycling of organic parts of the brine by - in one of the above-mentioned basic stages, preferably immediately following, Pre-stage, for example, by separation of gravity, in particular by centrifugation or filtration, from which - due to the water removal from the fresh vegetables, which is considerably diluted by the salt treatment - brine contains the particles of suspended matter, turbidity-causing substances and / or fiber materials contained therein - together with adherent and / or attached microorganisms or microorganism agglomerates - and, if appropriate, high-molecular organic compounds are separated and separated therefrom, that, if appropriate after passing through an intermediate stage with an intermediate layer erection, intermediate cleaning or the like, further
in a main stage, the salt concentration amounting to 1-3.5% by mass, in particular 1.5 to 2.5% by mass, in at least part of the thus pre-cleaned and stabilized brine itself or in an auxiliary solution brought into interaction with it Values approved for release to the environment, in particular to values of less than 0.2% by mass, are reduced (“diluate”), the salt concentration in the remaining part of the brine or in an auxiliary solution (without addition of fresh salt) a maximum of 30% by mass, preferably to 5 to 10% by mass, in particular to 7 to 8% by mass, is increased (“concentrate”), and that, if appropriate after passing through an intermediate stage with intermediate storage, intermediate cleaning or the like,
in a final stage the, preferably total, amount of the concentrate obtained in this way is recycled into the salt treatment of the fresh vegetables, in particular sliced cabbage, from the basic stage.

With the invention the task is accomplished, in particular in it exists, with the most economical use possible for the production of sour vegetables except for the raw vegetables and auxiliary materials to be used and if possible Low energy consumption is extremely from an ecological point of view unwanted, additional introduction of non-natural substances, in particular Cooking salt, into the environment by recycling it and reusing it to avoid use in your own process as far as possible. It will be in un in addition to the table salt, which mainly contains biogenic components Fresh brine to an output that is valuable for fresh vegetable salting repurposed fabric. Especially the biogenic ingredients of the sheets, such as. B. various carbohydrates, protein components, vegetable fibers, orga African acids, but also various microorganisms, are likely to be reasons have shown that the brine is largely recycled with multiple use of table salt in sauerkraut production  was not approached. With the leading to the invention, detailed Studies have shown that flexible and to the Use of raw material coordinated with the respective local circumstances fen, energy sources and existing technical facilities as well as at variable use of the by-products or waste products resulting from the process with a high rate of saving salt under environmental conditions economic conditions ensuring profitability make a significant contribution can be done for environmental relief.

It is an important feature that an approximately concentrated or saturated Saline solution, which contains the recycled NaCl, for the salting-in process Basic level is used. The fresh sheet is concentrated about 8% by mass NaCl and gives this the remaining, about two thirds of add a corresponding amount of fresh NaCl for the necessary amount of NaCl, with which a salt solution with about 23-25 mass% NaCl is obtained. The Salting the fresh vegetables with this solution proves to be special cheap, because it is surprisingly apart from the expected homogeneous Distribution to an accelerated breakup of the cell walls, that is to one Shortening the salting step itself, contributes and the quality of the preserved sauerkraut does not differ from that conventional and standard salted comparison batches differentiates.

If a preferred pre-stage approach like this characterized by claim 2, can be used make use of an effect that has not yet become known: namely, it was found that fresh brine, until now only known to be in goes into fermentation for a relatively short time, then is kept stable without any problems and can be stored or temporarily stored for up to two weeks if it of the suspended particles and fiber particles contained in it in essentials Measure is exempted, whereby a stabilization tried as usual so far tion by means of oxidizing agents, e.g. B. H₂O₂, can be omitted entirely. reason the fact that the pathogenic microorganisms, which lead to premature fermentation and thus lead to annoying odor development of the fresh brine, essentially to the in the suspended and fibrous materials contained are bound adhesively. So you can in the proposed separation of the same, very substantial portions of these disruptions organisms from the lake. So that's because of sai son-related, intermittent accumulation of large volumes of press liquor occurring The problem of necessary intermediate storage can now be solved elegantly.

In the preliminary stage, the suspended matter is separated by means of a centrifuge  provided, the advantage is to avoid - unpleasant Filter additions or the like. Given, and in particular also the preference of a continuous separation of the suspended matter with the essential Shares in pathogenic organisms. The effect of stabilizing the Fresh brine can be produced by a very fine Filtration can be increased significantly. Essentially, when centrifuging about 1-2% coarse fiber separation, with a fine filtration, however, an Ab Separation of up to about 0.5% extra fine and high molecular fractions expect.

Disposal of the - as be wrote - suspended and fibrous matter separated in the preliminary stage can in before can be achieved in a procedure according to claim 3.

Because these suspended solids etc. are valuable, sometimes easily digestible Components have been found, especially when animals are in close proximity husbandry and sour vegetable preparation use as animal feed as proven advantageous. These residues can also be removed by drying Win fiber-enriched animal feed additive.

As for the main stage of the new recycling process, there are the use of processes to concentrate the brine from the purely techni there are hardly any limits from a standpoint. This step is in any case with considerable energy expenditure and therefore represents an essential Cost factor, which of course depends on the general conditions, e.g. B. if straw that is otherwise difficult to use locally or that is produced in the neighborhood Biogas is available as an energy source for caloric lake constriction stands, can vary widely.

From the point of view of environmental protection and minimizing energy consumption with reasonable infrastructural effort, has increased the Sodium chloride concentration using an electrodialysis and / or reverse osmosis Process - as it is provided according to claim 4 - as special advantageous and in the context of brine recycling and liquid phase processing itself proved to be practically tailored.

This means that the third that has been lost or can only be used with difficulty the amount of common salt used to salt the fresh herb in total reached, can be recycled in a favorable manner in this salting process.

The following mode of operation of the electrodialysis process is outlined as typical:
The salt of the fresh brine is enriched with the help of an electrodialysis system in the electric field by cation and anion membranes on the concentrate side (e.g. up to 10% by mass NaCl in the solution), while at the same time the remaining brine on the so-called diluate side is largely desalinated (e.g. down to one twentieth of the original concentration, e.g. less than 0.1% by mass NaCl). After adding the required amount of fresh salt, the salt concentrate is used quantitatively for salting the fresh herb in the basic stage.

Assuming that the fresh sheet is about a third of the amount Contains table salt that was added when the herb was cut and that now this amount is almost quantitative (i.e. about 95%) from the fresh brine can be recovered by electrodialysis (in the form of the above mentioned This concentrate is then available for re-salting. The fresh salt addition is thus reduced by almost a third, what in addition to protecting the environment through undissolved amounts of salt also on the real costs side has a positive impact. The diluate, since it is almost only contains more of the organic components of the herb on the harvested Herb fields are spread. Also various other recovery Possibilities, as they are provided in the context of this invention, are available at.

In addition to the reduction in energy expenditure achievable by electrodialysis offer such systems also the advantage that they are suitable for decentralized use are much better suited than caloric systems.

Another important advantage of electrodialysis as part of the new The process is, in addition to the continuous operation and the minimized Energy expenditure (e.g. of about 28 kW / t brine) for the concentration, therein located that they have a simultaneous separation into a practically only more orga Mash and mulch containing niche brine components and one of the same free concentrate solution containing practically only salt, no significant organic substances that may interfere with the salting process has enabled. Finally, the effort to maintain the Functionality of the system can be kept low because even with one Clogging of the dialysis membranes by reversing the polarity easily blocks such blocks can be solved.

In a similar way, reverse osmosis processes, especially with modern, mechanically stable membranes are advantageous, with special synergy effects, both in the desalination of the liquid phase portion as well as especially on the economic side, e.g. B. more expensive with minimization Membrane area, are accessible.  

In this sense, the electrodialysis processes offer Main level following basic types of advantageous procedures.

• 1. Batch process (concentrate - like diluate side):
  Concentrate - like the diluate side, the chambers are filled with fresh brine and enriched or enriched until the desired discharge concentrations in the diluate or concentrate are reached. The current density, ie approx. 80% of the (specific) limit current density to be assigned to the diluate conductivity, is adapted to the respective diluate conductivity. When the discharge concentration is reached, the chamber is completely emptied and refilled with fresh brine. If driving in several stages, make sure that the hydraulic switching arrangement of concentrate and diluate is made in such a way that the concentration gradient in the cells between concentrate and diluate is as small as possible.
• 2. Batch process (diluate side):
  In this method, on the concentrate side, after the discharge concentration has been set with minimal hysteresis, as much fresh brine is fed in as the concentrate is discharged. This procedure is called Feed & Bleed. On the diluate side, as in point 1., is carried out in batches by adjusting the current density which is respectively adapted to the conductivity.
  These two advantageous variants are covered by claim 6, with the advantage of a particularly economical membrane insert with a membrane area saving.
• 3. Feed & Bleed process:
  In this method, both the concentrate and the diluate side are operated in the feed & bleed, the current density being based on the predefined diluate discharge concentration and, due to the low hysteresis, remaining almost constant during operation.
  In the case of multi-stage systems, it is again important to ensure that the concentration gradient between the retentate and the diluate in the stacks is as small as possible.
  By varying the hysteresis, intermediate stages between batch and feed & bleed procedures can also be carried out.
  This less expensive, less expensive operation is included in claim 7.
• 4. Two-stage or multi-stage feed & bleed process with stage variation with different current densities:
  The membrane area can be saved with a sequence of entry and discharge concentrations that is optimally coordinated on the diluate side. The idea for this is to combine the advantage of the membrane-gentle driving style of the feed & bleed process with a reduction in the membrane area. The salt content of the fresh brine is enriched on the concentrate side in a first stage to an intermediate concentration, which can be calculated from the initial concentration and the desired final concentrations, and is discharged at the desired final concentration in the second stage after discharge. On the diluate side, the salt content in the fresh brine is first reduced to an intermediate concentration in the second stage and discharged in the first stage when the final concentration is reached. Individual adjustment of the current densities in stages 1 and 2 saves membrane area, and the different order of the stage selection between retentate and diluate reduces the concentration gradient between the cells in the stacks. The optimal intermediate concentration (minimum membrane area, is calculated as follows:

The general formula for the calculation of the membrane area applies

The (non-variable) parameters that are insignificant for the present consideration are summarized in constant B.

Since the limit current density is approximately proportional to the concentration, fol relationship:

i _(c) = m · eq. 3rd

For a two-stage system in which the diluate side is depleted up to the concentration c _x in the first stage, the following simplified equation representation results:

The equation is used to determine the required minimum number of membranes dA / dx derived. The following results for the minimum number of membranes Equation:

The following applies to the optimal concentration gradation c _x :

c _{x (min)} = (C _a · C _e ) ^1/2 Eq. 6

Here are:

Q = amount of diluate
z = number of charges
F = Faraday constant
C _a = initial concentration
C _e = final concentration (diluate)
i _(ce) = current density at discharge concentration (diluate)
w = current efficiency
i _(c) = current density at diluate concentration (c)
m = proportionality factor
c _x = discharge concentration (intermediate stage diluate).

The intermediate diluate concentration to be set is thus calculated from the geometric mean of the initial and target final concentration. All other discharge concentrations result from the volume balance.

This advantageous multi-stage method is around claim 8 sums up.

The procedures for reverse osmosis are basically similar. As with electrodialysis, reverse osmosis can also be carried out using either the batch or feed & bleed process. The procedure to be selected depends on the given boundary conditions, such as the amount of permeate, throughput, concentration factor and the like. the like
A particularly advantageous combination is salt enrichment by electrodialysis after ultra-fine filtration with subsequent treatment of the ED diluate with reverse osmosis.

The brine is pre-cleaned in the preliminary stage, finely filtered and in the Main stage subjected to electrodialytic treatment. The organic Diluate is immediately contaminated by reverse osmosis using the Tangential flow, especially when using the Disk-Tube module system from the remaining organic substances including the proportion that causes COD and largely removed the residual salt content (<95%). The permeate that the Quality of partially demineralized water can safely enter the sewer be introduced or used as partially demineralized water. The Concentrate is recycled to the basic level.  

This technically favorable, operationally inexpensive, Technologically easy to control and inexpensive procedure se is covered by claims 9 and 10.

A further type of process, which is made possible by the rapid development in the membrane sector and which permits high enrichment rates and is therefore inexpensive, is high-pressure reverse osmosis after pressure-operated fine filtration:
The fresh brine is pre-cleaned and finely filtered as in the preliminary stage, and the permeate is immediately subjected to high-pressure reverse osmosis at 120-180 bar, in particular 140-160 bar, working pressure, using the tangential flow, in particular using the disk tube module system in the Subjected to batch operation. In this case, salt enrichment to about 8% NaCl is aimed at on the concentrate side. If the COD values are still too high, the permeate is fed to another UO stage.

The concentrate is returned to 24-26% NaCl content, Salted up and for the wet salting of a new batch of sauerkraut in the ground level returned.

The permeate, which has the quality of partially demineralized water, can be discharged into the sewer without hesitation or as partially demineralized water be used.

This advantageous type of procedure is covered by claim 11.

A combined method with the following is particularly preferred Practical procedure: After pre-cleaning and fine filtration in the pre-stage is the micro or ultra filtration permeate by reverse osmosis (UO) under Utilization of the tangential flow up to a concentration of about 4% NaCl thickened. The UO permeate can either be used as process water or are discharged into a sewage treatment plant. The retentate is in ent speaking proportions of an electrodialysis and retentate side Salted to about 8% NaCl or on the diluate side to about 2% NaCl depleted.

The retentate is in the basic stage for the wet salting of a new batch used. The diluate is returned to the new fine filtration and processed as described above. This method has the advantage that for the UO, since only salted up to a concentration of about 4% NaCl lower pressures will have to be applied. In addition, the electro dialysis due to the high discharge concentration on the diluate side with high current dense driving, and thus a small membrane area and quantity-specific  favorable energy expenditure, operated.

The remaining organic part in the retentate of the MF or UF is fresh water rinsed salt-free and can then be discharged.

This particularly economical to operate, advantageous Process variant is general and specific from the claims 12 and 13 includes.

Is there a cheap energy source, e.g. B. substantially in situ agricultural waste products with little other input set options, such as B. wood waste, straw, maize straw, biogas, for ver addition, the concentration or an intermediate concentration of the Lake in the main stage by caloric means, especially by means of Turbo compression evaporation under vacuum or by means of vacuum evaporation Heat pump can be made. It is roughly estimated with one Expect energy expenditure of less than 250 kWh / t brine. When using a system with electric heat pumps the energy expenditure is reduced to 120 kWh / t, with a turbo compressor to about 50 kWh / t.

If provided, individual, but in particular all process stages to carry out continuously what in stabilizing the fresh brine in the preliminary stage by balancing production peaks particularly easily is achievable, since temporary storage is no problem Plant capacities and production time can be used particularly cheaply.

If not all concentrate parts for a return to the Basic level are provided, e.g. B. after a higher number of cycles, a Discard these sheets that have been taken out of the cycle, i.e. uncoupled the manner stated in claim 14 can advantageously be avoided. This means that an increased mineral content can be found in animal feed itself and especially the table salt that is necessary for animal health (Leaking salt) can be integrated. It becomes digestive animal feed achieved.

Providing the procedure according to claim 15 neutralization of too acidic concentrates and a targeted introduction of minerals into the brine-treated feed or agricultural waste for feed purposes.

Additional drying effort can be avoided if in the brine concentrate the salt concentration is high enough to start with to ensure adequate storage stability. The concentrate can Consumers at the time - feeding directly the feed, e.g. B. hay,  Corn silage or straw, which has fiber function, can be added. More Weekly feeding tests have shown that the cattle always have one with the salt lak Concentrate preferred corn silage, but their milk showed no change in taste or other.

Another way to recycle excess brine Concentrates is the method according to claim 16, wherein the The advantage is that the salt is then digestive, organic Contains ingredients.

Finally, recycling is separated in the preliminary and main stages ten fibers and particles as animal feed according to claim 17 advantageous.

Another essential object of the invention is a Execution of the method according to the invention also suitable in its variants nete system, as outlined by claim 18. More special The advantage of such a system is its high flexibility and Integrated electrodialysis or reverse osmosis, including their decentralized use possibility.

A preferred plant embodiment, which of the claim 19 features included, enables because of their inexpensive Basic structure of an economically justifiable procedure, without essential to neglect ecological aspects.

This essentially also applies to the system variant according to An Proverb 20, with which even strict environmental requirements are still economical are achievable.

Particularly high demands with regard to cleaning from which he system according to the invention discharged material flows is capable one applied according to claim 21, an internal one System ensuring maximum return of contaminated material flows.

Finally, the subject of the invention is the use of the fresh Brine or press brine from sour vegetable preparation and especially from it Concentrates by recycling reintroduction into salt treatment, such as them from claims 22 and 23 with those specified there Is included.

The invention, in particular the system for Implementation of the procedure, explained in more detail.

According to the diagram in FIG. 1, freshly cut cabbage and table salt, as well as caraway seeds and other spices are introduced into a container 1 via conveying devices or feeders 2 , 3 , where they remain after appropriate mixing for an intended contact time. The saline-containing fresh brine separating from the fresh vegetables is discharged via a line 5 , the salted sauerkraut is finally discharged from the container 1 by means of the discharge device 4 . The fresh liquor line 5 opens in the arrangement shown into a fiber and suspended matter separation device 10 , for. B. a centrifuge in which about 1% of so-called coarse fiber is separated from the fresh brine and applied via a discharge 11 as a sturdy, solid sludge with about 50% water content and z. B. can be fed a feed or composting. Within the line 15 coming from the separating device 10 , an ultrafiltration device 13 - indicated by a broken line - can be provided, from which approximately up to 0.5% of fine or very fine material fractions, in the form of a suspension, are removed via a discharge 14 . Ultimately, the brine clarified in the precursor described passes through line 15 into the main stage with a device 20 for concentrating the fresh brine, while at the same time increasing the sodium chloride concentration to form a brine or brine concentrate. The device 20 is preferably an electrodialysis device; from it, diluates which contain the organic constituents and can be disposed of easily via lines 21 , 22 due to low saline content and possibly a non-recyclable concentrate are discharged via a discharge line, while via a recycling line 30 forming the recycle stage , within which an intermediate storage tank 31 can be arranged, the salt concentrate is recycled into the container 1 for salting the fresh vegetables. The additional amounts of common salt are introduced via a feed 32 into the brine concentrate to prepare an approximately 25% sodium hydroxide solution for salting the fresh vegetables.

Fig. 2 shows a diagram relating to the desalination performance of a herb-Frisch Lake in a powered with 1 volt electrodialysis system according to Example 2, wherein on the ordinate the electric conductivity in mS / cm, and the NaCl content in mass% and the abscissa the time is plotted in hours. It shows the high efficiency of the desalination of the brine in combination with the concentration of the electrolyte released from the dialysis, which is important for the salination of the basic stage, with which the salt content released during the salination with the brine is largely recycled.

Fig. 3, the diagram shows a two-stage electrodialysis process, the main stage of the process as, in particular because the membrane surfaces minimization is preferred, where the% -numbers specify only by way of example the sodium chloride concentration of the individual material streams. In the first stage 31 of the main stage 3 , "d" on the diluate side, the pre-cleaned fresh brine coming from the pre-stage 2 is introduced as a liquid phase stream 231 , it passes through after a first reduction in the salt concentration, finally passes through the second stage 31 'also on the diluate side " d "and leaves plant 3 as desalinated, practically environmentally safe (waste) water except for 0.1%.

A partial flow (about 30%) of the liquid flow 231 is first fed to the second stage 31 'of the electrodialysis 3 via line 231 ', passes through the same on the concentrate side "K", leaves it with increased salt concentration, then becomes the first stage 31 also on the concentrate side " k "and leaves the same as a salt concentration of about 8% by mass suitable for recycling into the basic stage of herb salting.

In principle, this system can also have more than two stages and it can be run both in batch and in particular in feed and bleed become.

Fig. 4 shows a simple plant embodiment as it is advantageously suitable for realizing a central utilization concept for fresh brine according to the invention.

The one-salt silos S₁, S₂. . . S _n of basic level 1 with salt application, z. B. spraying devices 9 , coming fresh sheets are combined in a manifold 111 and pass through fine filters 12 in buffer tanks 11 , from where the brine is fed via line 121 to an ultrafiltration device 21 of the preliminary stage 2 . The retentate separated there can be applied via line 217 to an agricultural area 7 or an animal feed 7 'added. From the filtration 21 , the now pre-cleaned brine passes via line 231 into the electrodialysis device 31 of the main stage 3 , the liquid phase drawn off on the diluate side via line 317 to the environment, e.g. B. on an agricultural area, can be dispensed while the concentrate passes via line 314 into the concentrate tank 41 of the final stage 4 (recycling) and after compensatory addition of sodium chloride, NaCl, via line 419 the saline spray devices 9 of the salt-in silos S₁ until S _{n is} supplied.

A further refined embodiment of a system according to the invention as shown in FIG. 5, with a designation that otherwise remains the same with respect to FIG. 4, has a reverse osmosis device 32 downstream of the electrodialysis 31 on the diluate side via line 332 for a diluate post-cleaning with retentate return line 322 to the inlet side supply line 121 for fresh brine the filtration device 21 of the preliminary stage 2 , from which the diluate side via line 327 an output, for. B. the same in a body of water. Like., Success conditions, since the downstream reverse osmosis brings an additional cleaning effect.

Finally, FIG. 6 relates to a system which is particularly effective with regard to liquid phase cleaning, the essential part of which - while the designation according to FIGS. 4 and 5 remains the same - is shown schematically, here in the main stage 3 a reverse osmosis device 32 with discharge line 327 , which is supplied via line 121 , a micro or ultrafilter 21 of the preliminary stage 2 and line 232 with pre-cleaned brine, is connected upstream of an electro-dialysis device 31 and this is connected via two lines 332 , 332 'with both the diluate and the concentrate side Lake supplied equal, pre-increased salt concentration. On the diluate side, only a salt concentration, which corresponds approximately to the fish brine salt concentration, is enriched, and the diluate is either via a line 311 into the inlet line 121 on the inlet side to the filtration device 21 or, preferably, via 323 into the line 232 to the reverse osmosis device 32 is returned while the concentrate of the electrodialysis 31 is returned to the basic salting stage 1 via a return line 314 of the final stage 4 .

A further detailed explanation of the invention is given by the following examples.

example 1 Recycling of table salt in sauerkraut production

300 kg sauerkraut were in two herb barrels, each with a content of 150 kg with a constant addition of a total of 6 kg of crystalline table salt (and some caraway and juniper berries). Within the first 72 Hours after cutting, 60 liters of brine with a total salt content fell of 2.14 kg NaCl and 0.13 kg KCl. The press sheet was centrifuged freed from 5.7 kg of suspended and fibrous particles and could do without Stabilization up to 72 h without loss of quality due to the onset of fermentation and stored temporarily without any noticeable deterioration in odor. Under It was overpressured to 21.4% of its output using a thin film evaporator concentrated volume.

In 60% of the concentrate (1.3 kg saline) was 1.3 kg crystalline table salt dissolved. This Lake, which is the one described  cut and containing the fresh salt was salted to 140 kg Fresh herb grown, i.e. recycled in the basic level.

This resulted in 40 l of lake (fresh brine) in the first 72 hours.

The finished fermented sauerkraut from incision 1 and incision 2 showed no difference in taste.

This type of recycling could be done up to five times in the same way without noticeable loss of taste from the one with the and the after concentrating recycled brine, fresh herb treated again and again won sauerkraut be carried out.

Example 2

A batch test was carried out with an electrodialysis (ED) laboratory system carried out, desalted on the 10 l brine (diluate side) and concentrated to 2 l centered (on the concentrate side). The operating parameters were 1 volt / cell and selected an overflow rate of 10 cm / s. Also of interest the desalination time from which the data for a large-scale plant are to be derived and the behavior of the membranes towards sauerkraut brine.

In FIG. 2, the decrease in conductivity in the diluate in function of time is illustrated. The original value of 39 mS / cm (corresponding to a salt concentration of 1.50% NaCl) dropped to 2 mS / cm (0.8% NaCl) within 8 hours. The measured current was 2.5 A at the beginning of the experiment and 0.5 A at the end. On the concentrate side, the conductivity increased to 105 mS / cm. This corresponds to a salt concentration of 6.43% NaCl. The current yield (electrochemical) for this experiment was approximately 50%. The analysis values of the starting brine, concentrate and diluate are summarized in a table below.

In the diluate, the COD value decreased by about 20% compared to the Starting sheet. This can be explained by the fact that only a small part of the organic substance is present in ionic form. The Lake became the diluate depleted to about 1/20 of their original NaCl content. The concentrate  (6.43% NaCl) showed none even after a long storage period at room temperature The smell of putrefaction has a good shelf life.

To summarize:

• - Desalination of the sauerkraut brine is economically feasible.
• - An approx. 5-fold salt concentration is possible.
• - The total energy consumption is, if you enrich the diluate Salt concentration of the cabbage sheet from 1.5% NaCl to 0.08% NaCl, at about 28 kWh / m³ diluate (water yield approx. 80%).

With this type of preparation, the lake could even after eight times recycling cycle, in which for salting an approximately 24% NaCl solution was prepared, no quality reduction on this new one Sauerkraut produced in this way can be observed.

The following was found regarding changes in the composition of the brine after several recycling steps:
The COD content and the Ma⁺ / K⁺ ratio in the fresh sheets were observed up to nine recycling stages and the sauerkraut was tested for its tasty quality and consistency. About 17-23 tons of raw cabbage were each salted wet with the brine concentrate from the previous stage. Apart from a certain spread, no change in the values was discernible with an increasing number of recycling stages. The taste and consistency of the sauerkraut also remained unchanged.

The following Table 1 shows an example of plants actually achieved services for micro and ultrafiltration, reverse osmosis and electrodialysis, depending on the NaCl content of the fresh brine.  

Claims (23)

1. Process for the treatment or further treatment of brine containing saline, in particular fresh brine, from the preparation of pickled vegetables, in particular sauerkraut, in which fresh vegetables, in particular fresh cabbage, in a comminuted, in particular cut, form with in a basic stage Saline solution is added and after each predetermined duration of action at least a large part of the brine formed is separated from the vegetables treated with it, in particular cabbage, and fed to a further processing, at least a part of the brine separated or pressed off after completion of the basic stage compensating addition of the amount of table salt corresponding to the amount of vegetables consumed is recycled in a table salt treatment of fresh vegetables, in particular cabbage, characterized in that environmentally compatible desalination is achieved by coordinated crosslinking of the individual process steps together with recycling of the table salt or demineralization of the liquid phase to be extracted from the lake with simultaneous environmentally friendly recycling of organic parts of the lake by

• - in a precursor, which immediately follows the basic step mentioned, for example by separation of gravity, in particular by centrifugation or filtration, from which - as a result of the water being removed from the fresh vegetables by salt treatment - brine the particles of suspended matter contained therein, Turbidity-causing substances and / or fiber materials - together with adhering and / or attached microorganisms or microorganism agglomerates - and possibly high-molecular organic compounds are separated and separated therefrom, that after passing through an intermediate stage with intermediate storage, intermediate cleaning or the like ., further
• - In a main stage, the salt concentration amounting to 1-3.5% by mass, in particular 1.5-2.5% by mass, in at least part of the thus pre-cleaned and stabilized brine itself or in an auxiliary solution brought into interaction with it to values approved for release to the environment, in particular to values of less than 0.2% by mass ("diluate"), the salt concentration in the remaining part of the brine or in an auxiliary solution (without fresh Salt addition) to a maximum of 30% by mass, preferably to 5-10% by mass, in particular to 7-8% by mass ("concentrate"), and that, if necessary after passing through an intermediate stage with intermediate storage, intermediate cleaning or the like .,
• - In a final stage, the preferably total amount of the concentrate obtained in this way is recycled into the salt treatment of the fresh vegetables, in particular sliced cabbage, of the basic stage.

2. The method according to claim 1, characterized in that the Fresh brine in the preliminary stage of a pressure-operated ultra-fine filtration, preferably wise using a tangential flow (cross flow), one Ultra filtration, preferably with a separation limit in the range of 15-150 kDalton, and / or a micro-filtration, preferably with a separation limit in the Range from 0.05 to 0.5 pm. 3. The method according to claim 1 or 2, characterized in that the suspended, turbid and / or fiber particles separated in the preliminary stage from the brine or in particular also higher molecular weight organic substances and remaining suspended matter are dewatered or concentrated from an ultrafiltration and the residue, sludge or the like thus obtained, optionally after desalination with essentially desalinated or fresh water, an animal feed (feed) and / or discharged onto an agricultural area and / or fed to composting. ( Fig. 4). 4. The method according to any one of claims 1 to 3, characterized records that in the preliminary stage of suspended, turbid and / or fibrous materials or their particles freed Lake to finally get to the Environmentally dispensable, essentially desalinated or demineralized (Waste) water in the main stage of the process an electrodialysis and / or Reverse osmosis process, if necessary with switching on or intermediate switching at least a (vacuum) evaporation process. 5. The method according to any one of claims 1 to 4, characterized records that at least in part, preferably in the whole, of the Pre-coming lake in the main stage by means of electrodialysis process di on the luat side, the salt concentration is reduced to environmentally acceptable values, especially especially desalinated or demineralized, while the Salt concentration in the remaining brine portion or in one, preferably having an initial concentration of at least 0.2% by mass of sodium chloride, Auxiliary solution to values of at most 30% by mass, preferably 5-10% by mass, in particular 7-8 mass%, which is in brine or auxiliary solution concentrate (concentrate side) removed and in the salting of the  Fresh vegetables, especially cabbage, the basic level is recycled. 6. The method according to any one of claims 1 to 5, characterized records that the electrodialysis process of the main stage at least on the diluate side is carried out discontinuously, in particular according to the "batch" process. 7. The method according to any one of claims 1 to 6, characterized records that the electrodialysis of the main stage on the concentrate and diluate side quasi-continuously or continuously, especially according to the "Feed and Bleed "process is carried out. 8. The method according to any one of claims 1 to 7, characterized in that a multistage, in particular two-stage, electrodialysis process is carried out in the main stage, the concentration gradient between diluate and concentrate being kept small, preferably part of those coming from the preliminary stage , Fresh brine is fed to the individual stages of the electrodialysis process while lowering its salt concentration on the diluate side in ascending order, and a respective remaining portion of the brine is increased starting from the last electrodialysis stage, increasing its salt concentration on the concentrate side, in descending order or vice versa the individual stages is led. ( Fig. 3). 9. The method according to any one of claims 1 to 8, characterized in that within the main stage, the diluate from the electrodialysis process, in particular for the separation of low-molecular organic substances or for lowering their content, including the proportion causing COD, preferably with simultaneous further reduction of the salt concentration is additionally subjected to a reverse osmosis or nanofiltration process, the permeate finally being discharged into a municipal sewage system, a receiving river or the like if desired, or optionally used as demineralized water. ( Fig. 5). 10. The method according to claim 9, characterized in that the concentrate obtained in the reverse osmosis of the precursor, in particular upstream before its ultra or micro-filtration, is supplied. ( Fig. 5). 11. The method according to any one of claims 1 to 10, characterized records that in the preliminary stage of suspended, turbid and / or fibrous Lake or its particles freed Lake to finally get it without any problems essentially desalinated or demineralized to be released into the environment (Waste) watering in the main stage of the process, one more, in particular two-stage, high pressure reverse osmosis process with concentrate side  Working pressures in the range of 120-180 bar, in particular 140-160 bar, preferably using a tangential flow, particularly preferred using a "disk tube module system". 12. The method according to any one of claims 1 to 22, characterized in that the fresh brine coming from the basic stage is freed in the preliminary stage by micro- and / or ultra-filtration of suspended, turbid and / or fiber material particles, which may be applied after salt-free washing, for example on an agricultural area,
that the brine thus obtained is first subjected to a reverse osmosis process in the course of the main stage, with demineralized or demineralized water, for example for use as process water, being drawn off, that the brine drawn off on the concentrate side, with an increased salt concentration compared to the fresh brine, in two streams is divided, which are fed on the concentrate side and diluate side to an electrodialysis process,
that finally, in the final stage, the concentrate, which has a further increased salt concentration, is compensated for by supplementing the table salt in the basic stage for salting the fresh vegetables, in particular fresh cabbage, while the diluate, which is electrodialytically depleted in the salt concentration of the fresh brine, optionally before entry the fresh brine is returned or reintroduced into the preliminary stage, but preferably into the brine freed from particles before it enters the reverse osmosis process of the main stage. ( Fig. 6). 13. The method according to claim 12, characterized in that a fresh brine with a salt concentration in the range of 1.5-2.5% by mass in the preliminary stage and further in the reverse osmosis process of the main stage is introduced, from which it - Divided into two streams - with a salt concentration in the range of 3.5-4.5% by mass in each case on the concentrate side and diluate side of the electrodialysis process of the main stage, and that finally the concentrate leaving the electrodialysis process is fed with a salt -Concentration of 7-8 mass% in the fresh vegetable salting of the basic stage is recycled, while the diluate from the electrodialysis process with a salt concentration in the range of 1.5-2.5 mass% before the fresh brine enters in the preliminary stage, but preferably in the brine freed from particles before their entry into the reverse osmosis process of the main stage, is reintroduced or reintroduced. ( Fig. 6). 14. The method according to any one of claims 1 to 13, characterized records that non-recycled portions of brine or especially Kon centrates, preferably from the main stage, in an animal feed (feed)  introduced and / or applied to such and / or in or with a feedable, cellulose-containing or -like substances Plant material forming carrier material, in particular straw, chaff, hay, Grain or fruit meal, bran, grain silage, mash and / or Corn cobs, preferably in comminuted form, can be introduced or applied, and by concentrating the aqueous phase, optionally drying, in one mineral-rich feed or feed additives are transferred. 15. The method according to claim 14, characterized in that not recycled portions of salt lake concentrates, especially before introduction in or application to an animal feed (by means of calcium) or magnesium oxide, hydroxide or carbonate are neutralized. 16. The method according to any one of claims 1 to 15, characterized indicates that non-recycled portions of brine concentrates, especially the main stage, by concentration to cattle or leaking salt are processed. 17. The method according to any one of claims 1 to 16, characterized records that in the preliminary stage and possibly in the main stage separated suspended, turbid and / or fibrous particles and given if high molecular weight organic substances either ver are fed or, preferably after dehydration, an animal feed (feed) be added. 18. Plant for carrying out the method according to one of claims 1 to 17, characterized by at least one, optionally pressurizable salt container ( 1 ) of a basic stage with conveying device ( 2 ) for introducing chopped or cut fresh vegetables, in particular Fresh cabbage, and such (3) for introducing table salt or its solution, further a conveying device ( 4 ) for discharging salted fresh vegetables, in particular fresh cabbage, and a derivative ( 5 ) of the freshly formed in the basic stage -Lake in one

• - A preliminary stage device ( 10 ) for separating suspended, turbid and / or fibrous particles and possibly high-molecular organic substances from the fresh brine with conveying device ( 11 ) for removing the said solids and discharging ( 15 ) the clarified fresh brine - preferably with very fine and / or ultrafiltration device ( 13 ) arranged in this with discharge ( 14 ) for solid particles separated there - into one
• - A device ( 20 ) forming a main stage, in particular electrodialysis and / or reverse osmosis system, for increasing the salt concentration of the fresh brine supplied from the preliminary stage or an auxiliary solution, from which main stage in addition to a discharge line ( 21 ) for at least partially demineralized water and one for removing used and / or non-recycled concentrate parts ( 22 )
• - A line ( 30 ) forming a final stage for recycling at least a main part of the concentrate led from the main stage, and is designed to open into the fresh incision or salting container ( 1 ) of the basic stage, in each case between or within the mentioned stages conveyor devices, storage, intermediate storage or buffer containers ( 31 ) or the like. Can be arranged.

19. Plant according to claim 18, characterized in that its preliminary stage ( 2 ) comprises an ultrafiltration device ( 21 ) with discharge lines ( 217 ) for the discharge of retentate, in particular particle sludge and. Like. On an agricultural area ( 7 ) and / or in an animal feed ( 7 ') and with a further guide ( 231 ) of the particle-free brine in an electrodialysis device ( 31 ) of the main stage ( 3 ), the continuation ( 231 ) divides into at least one partial power line opening at the diluate side and at least one at the concentrate side, and a diluate-side drain ( 317 ) for the release of at least partially demineralized (waste) water to the environment, e.g. B. on an agricultural area ( 7 ) and a concentrate-side continuation ( 314 ) in the recycling final stage ( 4 ). ( Fig. 4). 20. Plant according to claim 18 or 19, characterized in that the diluate-side discharge ( 332 ) of the electrodialysis device ( 31 ) of the main stage ( 3 ) before the diluate is released to the environment in a reverse osmosis or nanofiltration device ( 32 ) for a subsequent cleaning, from which a return line ( 322 ) opens into the supply line ( 121 ) for fresh brine in front of the ultrafiltration and / or ultrafiltration device ( 21 ) of the preliminary stage ( 2 ) and a discharge line ( 327 ) for discharge of water depleted of organic and COD-causing substances to the environment, e.g. B. a sewage treatment plant. ( Fig. 5). 21. Plant according to one of claims 18 to 20, characterized in that it forms a preliminary stage micro and / or ultra-filtration device ( 21 ) with removal ( 217 ) of particle sludge and brine continuation ( 231 ) in a reverse osmosis device ( 32 ) comprised by the main stage ( 3 ) with a drain ( 327 ) for at least partially demineralized (waste) water and two separate, respectively diluate and concentrate side in the electrodialysis also included by the main stage ( 3 ) - Device ( 31 ) has partial flow continuation lines, whereby from the electro dialysis device ( 31 ) on the concentrate side a continuation ( 314 ) into the final ( 4 ) and basic stage ( 1 ) and the diluate side into the fresh brine supply ( 121 ) of the filtration device ( 21 ) of the preliminary stage ( 2 ) and / or preferably into the continuation ( 231 ) for brine in the reverse osmosis device ( 32 ) of the main stage leading return line ( 323, 311 ). 22. Use of in the production of pickled vegetables, in particular another sauerkraut when treating freshly cut vegetables with table salt Fresh brine obtained with the proviso that it is from floating, Turbidity and fiber materials or their particles are essentially freed and their liquid phase is reduced in volume while increasing the salt concentration as a recycled brine concentrate for at least one more Salt treatment of newly introduced fresh vegetables, in particular Fresh herb. 23. Use according to claim 22, with the proviso of a through implementation of the method according to one of claims 1 to 17 or in a plant according to one of claims 18 to 21.