DE1592994C - Process for the extraction of oil or fat from sewage - Google Patents

Description

adjusted to 3.0 using a pH meter. This addition of lignosulfonic acid made the emulsion Broken.

The glue water treated in this way was passed from the pipeline into a 350 l container and from this to another centrifuge. In this was by centrifugation per cubic meter treated glue water

Containing 210 kg of sludge
69 kg dry matter, of which

9 kg lignosulfonic acid,
55 kg of proteins and

5 kg are other substances,

eliminated.

In addition, the centrifuge weighed 11 kg = about 12 1 oil excreted separately. The water leaving the centrifuge had the following analysis:

Dry matter 2.8%

Of this

Proteins 0.5%

inorganic compounds .... 1.8%

ül 0.3%

other 0.2%

The oil (from both the first and second centrifugations) was sent for refining and the sludge is dried in a dryer together with the press cake from the fishmeal factory.

It should be noted that the analyzes cited are average analyzes of an 8-hour activity, in which period a total of 15.3 m ^{3 of} glue water was passed through the system.

If centrifugation is specified as the separation method in the above, this is to be understood as that other separation methods known in the field of mechanical processes are also used can be.

Example II

Waste water from a herring fillet plant was subjected to centrifugation with and without the addition of ligninsulphonic acid. The water before and after the treatment was analyzed based on average samples taken such that water before and after centrifugation was removed every half hour for a period of 5 hours in both cases. In each period, 134 m ^{3 of} water passed. In the case where lignosulfonic acid was added, 68 kg of pure sodium ligninsulfonic acid and 60 kg of sulfuric acid were used.

Analysis results

Dry matter,%

Protein,%

oil,%

Water at
Centrifugation

1.55
0.76
0.76

Water after centrifugation without additives with additives

1.03 0.70 0.24

0.82 0.36 0.06

This means that the oil separation effect was: without addition:

0.52
0.76

30th

35 with addition:

0.70
0.76

x 100 = 68%,

x 100 = 92%.

Example III

2 × 9 m ^{3 of} water from a herring fillet factory were subjected to flotation by adding 8 kg of sodium lignosulfonic acid and 6 kg of sulfuric acid to one portion beforehand. After flotation, the top layer was scraped off and centrifuged after heating at 8O ⁰ C. The purified water was analyzed in the two cases after flotation and centrifugation:

Water before flotation

Water after flotation with additive without additive

Water after centrifugation with additive without additive

Dry matter,%.

Protein, %

oil,%

1.58
0.81
0.56

1.02
0.57
0.08

0.13
0.06
0.09

0.60 0.60 0.14

Example IV

2 χ 20 1 wastewater was exempted from a slaughterhouse. 8 g of sodium lignosulfonic acid and 5 g of conc. H ₂ SO ₄ added. Both portions were in

60 dry matter,%

Left to stand for 2 hours, during which a foam formed on the surface and part of it sedimented as a precipitate,% fat. The relatively clear water in the middle

and the starting water were analyzed: protein. %

U.N-

treated
water

0.62
0.18
0.25

water

standing

with addition

0.12 0.04 0.04

In 2 hours without any additions

0.35 0.10. 0.20

Claims (3)

1 2 conditions leads through a second centrifuge, claims: Then the separation of the largest amount of the residual oil takes place. However, it is not necessary to do so 1. Process for the extraction of oil and fat. One can take advantage of the Ligninsulfonaus Wastewater by separation, characterized by 5 acid, before the separation under the designation mentioned, that one takes place before the separation conditions, add. the waste water ligninsulphonic acid or a derivative The method according to the invention is next- the same or lignosulfonic acid-containing material with some exemplary embodiments adds, whereby the pH of the wastewater will be on. 2.0 to 4.5 is adjusted. _I0 example I 2. The method according to claim 1, characterized in that that the pH is regulated to 3.0. The so-called glue water from the fishmeal 3. The method according to claim 1 and 2, characterized factories normally contains 10 to 15%, often unmarked, that the temperature of the ab- aby 13% dry matter (oils and fats water is set to 80 to 100 ° C. 15 calculated here as dry substances; this designation here includes all non-aqueous components), __ _j which is often about 1% table salt, 2 to 6% oil and about 9% is divided into proteins, vitamins and other organic matter. The present invention relates to a method of 20 The normal method of cleaning glue lines for the extraction of fats or oils from water and for the extraction of useful substances in it, Waste water, preferably from fishmeal factories, or remove as much oil as possible by centrifugation fish processing industries, slaughterhouses and then evaporate the rest. The Sars, leg meal factories, dairies and wool laundry oil or the solid material consist of glycerine esters tear. 25 saturated and unsaturated fatty acids and are on The named types of waste water turn into a valuable product. These oils can be found in several cases in oils or fats obtained by centrifugal glue water, as it comes off the factory in the form of blocking, flotation or by scraping off the uppermost phase in a finely divided emulsion, layer obtained after standing (fat trap). This continuous phase is water, in which the extraction of oil is particularly economical ₃₀ the other substances are dissolved, possibly of importance when it is about glue water or, to a certain extent, as suspending particle water from the fillet preparation of herrings will. since the oil content of these two types of water is high (the oil from the glue water by centrifugation usually 1.5 to 6%). However, when using the pre-remove one gives an unsatisfactory one lying invention is the yield of oil or 35 result, since the glue water after centrifugation Fat increased relative to known methods. in practice always contains 1 to 1.5% oil and theoretically This means that even the oil or fat content of other tables cannot be reduced to an oil content by centrifugation Types of waste water more economically- brought from below about 0.5% (weight percent) be used. Furthermore, according to the invention, the can become. Waste water pollution levels reduced, as was 40 The glue water from a fishmeal factory z. B. when measuring the biological oxygen consumption in a known way through a centrifuge, needs can be measured. with 3.6% oil excreted. After this According to the invention, lignin is added to the wastewater. First centrifugation, the water had a temperature sulfonic acid or a derivative thereof or a lignin door of 70 ° C and the following analysis: sulfonic acid-containing material added, the 45 _,. , "" ", pH value of the wastewater to 2.0 to 4.5 and 9.8% with dry substance outwards looking for better separation the temperature to 80 to that: 100 ° C can be regulated. Here it happens over- oil 1.4% surprising that the oil-in-water emulsion broken proteins 6.0% and you can therefore use a larger amount of the 50 other organic compounds 0.6% Separate oil than is otherwise possible. For practical inorganic compounds 1.8% You can work here without any difficulty oil residue in the water from 0.02 to 0.2%, depending on the oil remaining in the water can be removed from the Type of water. One also achieves with the glue water through further or more effective central this method has the advantage that the proteins are not excreted during trifugation, precipitated early, so that both components of the first centrifuge was the water in can be exploited. According to the invention, a thermostat-controlled intermediate container also adjusts it is most expedient to adjust the pH to 3.0, in a size of 14 m ³ , in which the which it has been shown that a better temperature of the water with the help of steam prey is reached, d. H. the separation of the largest 60 88 to 90 ° C was raised. This container became amount of oil (and by the way also protein). the water is pumped through a pipeline. In the It should be noted that in the case of practical piping one was continuously using lignosulfonic acid Working a preliminary separation of part of the and sulfuric acid added by the addition Making oil in a manner known per se was controlled by a pH measuring apparatus. the can, so that one first the water in untreated 65 ligninsulfonic acid was in a 15% aqueous Condition, e.g. B. can pass through a centrifuge and add a solution containing 8% sulfuric acid, then the ligninsulphonic acid is added and then the 10 kg of ligninsulphonic acid per cubic centimeter water treated in this way was added under the specified meter of glue water, and the pH value was determined