FI104689B - Process for the treatment of whey - Google Patents

Description

104689

METHOD FOR HANDLING WHEAT

The present invention relates to a process for treating whey obtained from cheese milk processing in cheese making, wherein the separated whey is introduced into a pasteurization device, from a pasteurization device to a nanofiltration device, from which the whey permeate portion is diverted and the retention

The food industry processes waste water which is purified by passing it through nano and / or microfilters. The whey formed during the processing of the milk in the cheese industry is salty and is passed to a filtration apparatus for desalting. The permeate portion from the filter device is also waste water because of its high salinity. Such waste water is discharged as waste water to, for example, an industrial plant or municipal sewage treatment plant or directly to a lake or water body. Water and wastewater prices are high and large amounts of wastewater have to pay high costs, even if the wastewater is almost pure.

Another disadvantage of the current procedure is that any useful substances ·· that may be present in the perme-25 constituent are wasted. In this case, it may be necessary to purchase a new, similar substance in the process in place of the substance which is removed with the permeate as waste water. Recycling the permeate moiety back into the process may not currently produce satisfactory results, since recycling may enrich unwanted substances with the nanofilter.

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It is an object of the invention to provide a process for reducing waste water and for utilizing the permeate moiety and the ingredients contained therein in the process. It is a further object of the invention to provide a method which is simply and • *.

2 104689 is preferably feasible and usable.

The object of the invention is achieved by a process which is characterized by what is claimed.

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In the method of the invention, the retentate portion is led from the storage to an electrodialysis apparatus, where it is treated by electrodialysis to lower the salt content of the whey, and the brine is fed through an intermediate storage to a nanofiltration apparatus. In addition, the whey permeate portion is further processed after the nanofiltration apparatus in a reverse osmosis filtration apparatus to provide technically pure water, which water is diverted to intermediate storage 15 and further to water-intensive electrodialysis, other cycles, or directly to the water system. The permeate is technically pure and can be utilized in the process at many different points by recycle it back into the process. The amount of both wastewater and water entering the process can be significantly reduced, resulting in cost savings. However, if the permeate is to be discharged into the sewer, it is sufficiently clean and can be discharged directly into, for example, water, at least if any bacteria have been destroyed. In many cases, 25 permeate purified by an additional filter (RO) is useful in the process and ·· Purchases of process materials can be reduced. The invention is suitable for use at least in the purification of waste water from processes in the food industry and especially in the manufacture of cheese.

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In the application of the method of the invention, the permeate ·· is sterilized by UV light to eliminate 'harmful substances and bacteria'. 1 ··

In another further embodiment of the invention, the permeate is pasteurized after an additional filter (RO). The pasteurisation is preferably carried out at a temperature of from about 75 ° C to about 90 ° C, thereby reducing the amount of harmful substances.

One important addition to the process is that the pure water from the process is preferably mixed with condensate water.

5 This results in water that meets strict environmental requirements and can be discharged directly into a watercourse or discharged into a closed loop. In this case e.g. the electrical conductivity values from about 300 microS are significantly further improved by mixing the conductive-10 condensation water of e.g.

The invention will now be explained in more detail with reference to the accompanying drawing, in which Figure 1 schematically shows an apparatus for applying the method of the invention, Figure 2 schematically shows another apparatus for applying the method of the invention, and Figure 3 schematically shows a third apparatus for applying the method of the invention.

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Figure 1 shows an example of a process according to the application; In the process, the salted, separated whey is cooled to a temperature below 10'C, preferably about 6'C, and is passed from the process to a storage tank 1, from where it is led to a pasteurization apparatus 2. The pasteurization in the apparatus involves whey paste. · Set at about 70-80'C, and preferably about 75'C,

followed by cooling to a temperature of about 15-25'C and preferably about 20'C. The salty whey is further directed to J

filter apparatus 3, which is a nanofilter apparatus.

After filtration, the permeate formed at a temperature of about 15 ° C to about 25 ° C, with a solids content of about 0.3% to about 0.5%, is led to an additional filtration apparatus 4 where the reverse osmosis apparatus purifies the permeate and provides technically pure water. As shown in the diagram, the permeate obtained from the RO filter 4 is initially treated by pasteurisation in pasteurizer 6 and / or sterilized by UV irradiation in UV apparatus 5. Thereafter, ··· 104689 purified permeate can be introduced into water tanks 7, 8 where it can be stored and from there further leads to various process drives or the like such as for example an electrodialysis device or possibly a drain. Permeate '5 is technically pure water and has a measured conductivity of about 150 microS to 300 microS. In the method, the permeate can also be introduced, after the filter 3, into a separate brine storage tank where it is stored for the desired time. Permeate storage tank 10 can be re-eg. The saline side of the use of the equipment 12. Preferably, 23 of the process water is mixed with condensate water. The condensate water can be discharged directly into the water system or discharged into a closed circuit.

In the embodiment and example of Figure 2, the treatment of the permeate is substantially the same as that described above. The retentate is also discussed in this application. In the process, the retentate from the filter apparatus 3 is heated at a temperature of about 20 ° C with a heat exchanger 9 to a temperature of about 35-45 ° C, 20 and preferably about 38 ° C. Such retentate has a dry matter content of about 24%. It should be noted that an evaporator can also be used instead of the NF filter. Next, the retentate is centrifuged with a spinning apparatus 10 to remove the crystals and fed to a storage tank 11.

Next, the retentate, or whey, is introduced into the electrodialysis apparatus 12, where it is desalted.

The salt content of the whey from this equipment depends on the extent of removal. The whey is drained 24 and the resultant salt water (ka 1.1-1.3%) is led to an intermediate tank 13 and cooled to a temperature of about 20 ° C, then passed to a nanofiltration apparatus 14. The permeate obtained here having a dry solids content of about 0.3 -0.5, is further introduced into a reverse osmosis filter 15. The permeate is then transferred, as described above, after pasteurization and / or UV-35 irradiation into storage tanks 7, 8, to which condensate water can also be introduced.

104689! 5

In an alternative process, the permeate is led directly from the nanofilter 3 to the RO filter 4 and subsequently pasteurized and / or UV irradiated to storage tanks 7, 8.

5

In the third embodiment and example of the invention, the process flow is substantially the same as in the example of Figure 2. In this embodiment, brine is led from intermediate storage 13 to a precipitation tank 16 where it is precipitated by addition of sodium hydroxide (NaOH) and brine, the resulting solution is centrifuged in a spinning device 17, and the resulting calcium phosphate precipitate is transferred from the , from which the permeate 15 obtained is passed to a further filter 22 and further as previously described. By such a procedure will the calcium and phosphate be recovered and the amount of precipitate reduced, thus preventing the nanofilter 21 from being clogged and working better, and the removal of phosphorus will be more efficient? most of the phosphorus is removed by centrifugation at 20 centrifuges 17.

The invention is not limited to the preferred embodiments shown, but may vary within the scope of the inventive idea of the claims.

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Claims (6)

104689 6 A process for treating whey from cheese milk processing in cheese making, wherein the separated whey is introduced into a pasteurization device (2), from a pasteurization device to a nanofiltration device (3), from which the permeate moiety is transferred, and ), it is centrifuged with a spinning apparatus 10 (10) and fed to a storage (11), characterized in that the retentate portion from the storage is fed to an electrodialysis apparatus (12) where it is treated by electrodialysis to reduce whey salt content; 14) and further to a reverse osmosis filter device (15) from which water is led to intermediate water stores (8), and that the whey permeate is further treated after the nano-filtration device (3) in a reverse osmosis filter device (4) which water is diverted to intermediate storage (7) and further to water-intensive electrode dialysis (12), other cycles, or directly to the body of water. • · Process according to claim 1, characterized in that the whey permeate is sterilized by UV light (5) after one or more reverse osmosis filtrations. Process according to claim 1 or 2, characterized in that the whey permeate is pasteurized (6); · · · After 30 kicks or some reverse osmosis filtration. i% The method of claim 1, known in the art! From the intermediate brine (13) to the precipitation tank (16) where it is mixed by adding Ψ saline brine and sodium hydroxide (NaOH), the resulting solution is centrifuged with a spinning device (17) and the resulting solution 5 is introduced into the intermediate tank (18) calcium phosphate precipitate [is introduced into a second container (19). ' A method according to claim 4, characterized in that the solution is introduced from the intermediate vessel (18) into a nano filter apparatus (21), from which the permeate is led to a reverse osmosis filter (22) and further sterilized by UV light (5) . Method according to one or more of Claims 1 to 5, characterized in that (23) condensate water is mixed with the clean water from the process to produce water meeting the environmental requirements, which is discharged directly into the water system or taken into a closed loop. 20 • «1 .., · 8 104689