DK146613B - PROCEDURES FOR THE REMOVAL AND RECOVERY OF DISPOSITION MATERIAL FROM PRECEDENT PROTEIN MATERIAL - Google Patents

Description

(19) DENMARK (W)

fj | (12) PUBLICATION OF 146613 B

Utesaf

DIRECTORATE OF THE PATENT AND TRADEMARKET SYSTEM

(21) Patent Application No .: 3343/75 (51) InLCI.3: A23J 1/16 P 02 F 11/14 (22) Filing Date: 23 Jul 1975 (41) Aim. available: 25 Jan 1976 (44) Submitted: 21 Nov 1983 (86) International Application No: - (30) Priority: 24 Jul 1974NO742703 (71) Applicant: A / S 'APOTHEKERNES LABORATORY FOR SPECIAL PREPARATIONS; Oslo 2, NO.

(72) Inventor: Per Oscar 'Nettli; NO.

(74) Plenipotentiary: Office of Industrial Energetic ______ (54) Procedure for Removal and Recovery of Precipitating Agent from Precipitated Protein Material ffl J2 It is well known to use some substances as industrial precipitating agents in the recovery of protein materials from The most important group of precipitating agents used are probably the lignin sulfonic acids and their derivatives Q. A number of plants based on the use of lignin sulfonic acids have been built in a number of countries and these plants are used to purify industrial wastewater during simultaneous recovery of significant amounts of proteins, see, e.g., U.S. Pat.

3-390999. Other organic substances that have been used as precipitating agents are organic sulfonates, e.g. hexavalent carbohydrates, and reference is made in this connection to Norwegian Patent Specification No. 117,339 and Canadian Patent Specification no.

887,899. Most of these organic sulfonic acids and sulphates provide excellent cleaning effect, but their use in industrial scale water treatment entails relatively high chemical costs. Furthermore, it is known that proteins which are precipitated with said precipitating agents can be used as feed. However, it would be advantageous to be able to reduce the content of the aforementioned precipitating agents. By reducing the content of precipitating agents in the precipitated material, it will be possible to increase the protein content and thus increase the commercial value of the material as feed.

In the known methods for precipitating proteins, especially from industrial wastewater, the precipitate is separated from the aqueous phase by some mechanical method, for example flotation which produces a sludge with a dry matter content between 5 and 15%.

This sludge often has to be concentrated further before it is finally treated. The concentration can be carried out, for example, by filtration or centrifugation after pretreatment with, for example, heat and / or addition of lime in a manner known per se, for example as described in the description in Norwegian patent application No. 903/72. This appears to be a relatively effective concentration method, but the major part of the precipitant remains in the sludge phase, and a disproportionate proportion of the proteins follow the liquid phase.

146613 3

It has now surprisingly been found that an improved removal and recovery of the precipitant can be achieved without excessive sludge phase degradation by, so to speak, dividing said known process into two steps, namely, adding an alkaline earth metal ion-forming compound first, in particular, one which forms calcium ions which are non-basic; and then made basic with an alkali metal hydroxide. The soil-eel-calcium compound, in particular an alkaline-earth metal salt such as calcium chloride, causes the proteins to coagulate as an alkaline-earth metal proteinate, and the alkali metal hydroxide dissolves in the aqueous phase as the alkali metal salt thereof, which is easily soluble in water, and is easily soluble in water. recovery of the precipitant.

Accordingly, the invention relates to a process of the kind set forth in claim 1 for removing and recovering precipitant from precipitated protein-containing material, and this method is characterized in that the proteins in the protein-containing material are bound by alkaline earth metal ions by a non-basic the alkaline earth metal compound and the material are then made basic by means of an alkali metal hydroxide before heating and dewatering.

According to the invention, alkali metal hydroxide is suitably added to a pH of 7.5-9. It has been found that this relatively weak base effect is sufficient for good recovery of the precipitant; and the weaker the base work done, the cheaper the process becomes.

The process according to the invention will now be described in more detail by some examples, and the drawing. In the drawing, FIG. 1 and 2 illustrate some curves illustrating the effect of the method according to the invention.

Of these curves, curves 3 and 4 refer to the method of the invention as represented by Example 1, Curves 1 and 2 to a somewhat different technique as represented by the comparative example.

In FIG. 1 (curves 1 and 3), the abscissa indicates the dosage of lignin sulfonate in mg / 1 and the ordinate COD of the decantate, expressed at mg 02 / l. In FIG. 2 (curves 2 and 4) indicate the abscissa of the centrifuge volume in ml, while the ordinate indicates the same as in fig. First

146613 4

Example 1

In this experiment, a lignoprotein mud separated by precipitation of the protein from wastewater was used with 14.5% dry matter from a slaughterhouse. The sludge had a pH of 4.1. To the sludge a certain amount of calcium chloride was added, followed by pH adjustment with sodium hydroxide to pH = 8.0. The slurry was then heated to 95 ° C, whereby a coagulation occurred, and after sufficient residence time and reaction time at this temperature, the sample was centrifuged. The centrifuge was analyzed and used as a source of lignosulfonate by adding a certain amount to a protein solution and adding a varying amount of lignosulfonic acid.

Surprisingly, it was found that by using this centrifugate as a precipitant, a much better precipitation of the proteins was obtained, so that the resulting liquid phase became clear and pure. The liquid phase of the samples was analyzed for COD to indicate the recovery of the protein precipitant. The test results are shown in the table below.

Table for Example 1

Dosages (to 500 ml protein COD in% COD Curve solution). dean reduction no.

- tat tion

Lignosul Sulfuric Acid Centrifuge, mg / l mg / l hole, ml 0 0 0 4690 0 0 600 0 3886 17.14 0 700 .5 1126 75.99 50 "" 1084 76.88 100 "" 1117 76.18 150 "" 1148 75.52 3 200 "" 1173 74.98 250 "" 1210 74.20 0 700 5 1126 75.99 0 "10 1146 75.56 4 0" 15 1312 72.02 5 146613

The results of Example 1 can be compared with the results of the comparative example by comparing curve 3 (example 1) with curve 1 (the comparison example) and curve 4 (example 1) with curve 2 (the comparison example).

Curve 3 shows, relative to curve 1, that in Example 1 a better COD reduction is obtained than in the comparative example and that the optimal dosage is somewhat lower than in this.

This means that the centrifugate produced by coagulation with CaCl 2 and NaOH contains a greater amount of precipitant than in the comparative example.

This relationship is further elucidated by comparing the results of protein precipitation experiments with centrifuges alone.

Curve 4 (Example 1) is clearly below Curve 2 (Comparative Example), which shows that the specific COD reduction is better with the centrifugate of Example 1. Furthermore, Curve 4 shows a smaller increase than Curve 2 by increasing the amount of centrifugate beyond that. optimal dosage, which means that the proportion of substances without protein precipitating properties must be smaller in the centrifugate from Example 1 than the corresponding one from the comparative example.

Example 2

Two portions of each 100 g of the same lignoprotein sludge as in Example 1 were coagulated at 95 ° C after addition of CaCl 2 and NaOH, respectively, thereby adjusting the pH to 9.

The portions were dewatered in two different ways so that one portion of the conditioning was centrifuged as in the previous example, while the other was filtered on a fiberglass filter and washed twice with 50 ml of water. Centrifugate and filtrate amounts were measured and the concentration of the precipitant determined by protein precipitation experiments as in the previous example.

6 146613

results

Condition Drainage Quantity Felling agent method liquid phase yield_ ml Concentration Gene% yield tration won mg / ml mg

CaClp + Centrifuge 58.6 2.030 66.6

NaOH

CaClp + Filtration 121 20 2.420 79.5

NaOH

In addition, the filtration rate and volume yield were examined using cold (15 ° C) and hot (65 ° C) water, respectively, to wash out coagulated material. In addition, experiments were made with the addition of cold water (15 ° C) after the coagulation as well as stirring to cool the material before separation. These additional experiments showed that, as expected, the filtration rate and volume yield were greatest when using hot water to leach the coagulated material, but by adding cold, water and stirring prior to separation, even greater filtration rate and volume yield were obtained for the liquid phase. Cooling of the material to approx. Therefore, 50 ° C prior to separation appears to be advantageous.

The precipitation yield shows that conditioning with CaClp and NaOH before coagulation provides good recovery of precipitant from the protein material.

The lignoprotein sludge used with a dry matter content of 14.5%, based on the consumption of lignin sulfonate in the preparation of the sludge and according to residual analysis of lignin sulfonate in the treated wastewater, contains 21% lignin sulfonate in the dry matter, which corresponds to 14.5 X 0.21 = 3.045 mg of lignin sulfonate in 100 g of sludge. As shown in the table, for coagulated sludge after conditioning with CaClp + NaOH by washing, the recovery yield of precipitant is obtained from 66.6 to 79.5%.

7 146613

comparison Example

This used the same lignoprotein sludge as in Example 1, but the treatment consisted of adding lime to raise the ρΗ value to 8.0. Then the sludge was heated to a temperature of 95 ° C at which temperature the sludge coagulated. After sufficient residence time and reaction time, the slurry was centrifuged. The centrifugate was then used as a precipitant for a protein solution knowing the optimal dosage of pure lignosulfonic acid. A certain amount of the centrifugate was added to the protein solution along with varying amounts of lignosulfonic acid. The protein material in the solution precipitated and the organic matter was measured in the resulting decantate by determination of COD.

As protein solutions in the recovery experiment, slaughterhouse wastewater of the same quality was used to precipitate the lignoprotein sludge investigated. The test results are shown in the table below.

8 146613

Table for the Comparative Example.

Dosages (to 500 ml protein COD in% COD Curve solution). dean reduction no.

-— tat tion

Lignosul Sulfuric Acid Centrifuge 2 // 1 phonate, mg / l mg / l hole, ml 0 0 0 4690 0 0 600 0 3886 17.14 0 700 5 1259 73.15 50 "" 1178 74.89 100 "" 1189 74.64 1 150 · "" 1239 73.59 200 "" 1276 72.79 250 "" 1300 72.29 0 600 0 3886 17.14 0 700 5 1259 73.15 2 0 "10 1341 71.41 0 , r 15 1706 63.64

The table and the curves clearly show that the best result with precipitation of protein solution with the centrifugate alone was obtained by adding 5 ml of centrifugate to 500 ml of protein solution. In this case, the COD reduction is 73.15% versus 17.14% when sulfuric acid is added alone. Curve 2 shows that the optimum amount of centrifugate to precipitate the protein solution should be approx. 8 ml per 500 ml, whereby a COD value in the decantate of about 1190 mg O2 / I would be obtained, corresponding to a COD reduction of approx. 74.6%.