DD249378A3 - METHOD FOR THE CLEANING OF WASTEWATERS AND PROCESSING WATERS OF MICROBIOLOGICAL PROTEIN RECOVERY - Google Patents

Abstract

The invention relates to a process for the purification of waste waters and process wastes of microbiological protein production from petroleum distillate. The aim of the invention is to reduce the waste water load and the recovery of valuable ingredients from the effluents and process waters. The method is based on the fact that from the effluents and process waters of microbiological protein production in the p H range 3-11 simultaneously dissolved, colloidal and emulsified substances are continuously removed, which then by known methods, such as filtration, ultrafiltration, separation or flotation, concentrated and be reintroduced into the process of microbiological protein production.

Description

Field of application of the invention

The invention relates to a process for the purification of wastewater and process waters of microbiological protein extraction from petroleum distillate. The invention is applicable to wastewater treatment of technical microbiology.

Characteristic of the known technical solutions

In a variety of industrial wastewater flocculation is the preferred method for the separation of ingredients application.

The purification of the effluents of the microbiological processes is known to present special problems because they contain large quantities of dissolved and cell-bound organic and inorganic substances. These are lost to the production process and cause a high sewage pollution. These are predominantly ingredients such as microorganism cells, carbohydrates, proteins, nucleic acids, fats, phosphates, metal ions and surfactants. In microbiological processes, in which liquid hydrocarbons are used as a source of carbon and energy, the oil phase, which enters the wastewater as a stable emulsion, exacerbates the flocculation behavior of the wastewater.

In the patent literature methods have hitherto been known which describe only the separation of individual substance classes or microorganism cells.

Object of the invention

The aim of the invention is to develop a universally applicable, independent of the mode of operation of the microbiological protein extraction cleaning process for wastewater and process waters of microbiological protein production of different composition and load with water-soluble ingredients and petroleum distillate, which is suitable for reducing the wastewater pollution, in the cheap and available flocculants are used and in addition, in a simple manner, the recovery of valuable organic ingredients from the effluents and process waters allows.

Explanation of the essence of the invention

The invention has for its object to develop a method which by means of chemical flocculation and pH influence using cheap raw materials and auxiliaries with a few process steps, the reduction of wastewater load in the microbiological protein extraction from petroleum distillate and in addition the recovery of valuable organic water ingredients guaranteed. According to the invention, the technical task of removing and / or recovering the complexly composed water constituents of microbiological and chemical origin and the microorganism cells from wastewater and process waters of microbiological protein extraction from petroleum distillate by means of chemical flocculation with conventional flocculants and pH-influencing, and process waters of microbiological protein production in the pH range 3-11 simultaneously dissolved, colloidal and emulsified substances continuously

be removed. These substances are then concentrated by known methods such as filtration, ultrafiltration, separation or flotation and fed back to the process of microbiological protein production. When using the flocculants, the following pH values must be observed: -Kalkmilch 8-11

Lime / polydiallyldimethylammonium chloride or lime / polyethyleneimine mixtures 8

Ferric chloride or ferric sulfate 3-8.5

- ferric chloride / polyethyleneimine mixtures 6-8.5

- ferric chloride / aluminum chloride mixtures 5.5-8

There is a direct correlation between the optimum flocculant concentration and the load of various waste waters with complex organic ingredients and emulsified petroleum distillate.

The observance of the pH conditions according to the invention for the individual variants is of primary importance. The effluent to be treated as described above constitute a multi-phase mixture consisting of

- dissolved substances, such as amino acids, fatty acids, mono- and disaccharides

- Colloidal substances, such as proteins, fats, polysaccharides

- coarsely dispersed substances, such as bacteria and yeasts and

- emulsified substances such as petroleum distillate.

The petroleum distillate water emulsion is extremely stabilized by a surfactant consisting of polyethylene-propylene oxide and complex-composed adsorbent layers of wastewater ingredients of unknown composition.

It has surprisingly been found that destruction of this emulsion and flocculation takes place at defined pH values by addition of conventional flocculants.

It was found that with all the above-mentioned flocculants at pH 8 very high reductions in the content of dissolved, colloidal, emulsified and coarse-disperse substances were achieved. When using the salts of the trivalent metal ions Fe ³⁺ and Al ^{3+, it} is not necessary to raise the pH of the normally slightly acidic (pH 4-6) wastewater.

With this procedure, it is possible to achieve CSV-Cr reductions of up to 95% and petroleum distillate reductions of approximately 100% in the waste water of microbial protein recovery from petroleum distillate.

At the same time, up to 90% of the feed yeast contained in the process waters can be recovered.

The method was tested under the conditions of the invention over a longer period of time with different modes of operation of the microbiological protein production and ensures a reproducible effectiveness.

embodiments example 1

Partial streams of process water and total effluents of microbiological protein production were treated on a laboratory scale with different modes of microbiological protein production with flocculants after defined pH values were available.

To characterize the effectiveness of the flocculation process according to the invention, CSV Cr and petroleum distillate analyzes of the untreated and flocculated samples were used.

In the originally milky-turbid and yellow to gray / black wastewaters spontaneous separation of the organic ingredients and the emulsified oil takes place after addition of the flocculants according to the invention within a few minutes, resulting in clear, lightly colored solutions. The expression for this is the very high reductions of the CSV-Cr and the petroleum distillate value shown in Table 1.

Example 2

The process water partial streams of the microbiological protein production were treated individually and in a mixture with 5% lime milk on a laboratory scale.

To characterize the effectiveness of the flocculation process according to the invention, CSV-Cr, dry matter, carbohydrate, fatty acid and petroleum distillate analyzes of the untreated and flocculated samples were used (see Table 2).

flocculation (G / i) pH CSV-Cr (gO ₂ / l) to flocculation 5.3 CSV Cr -3- to 249,378 Table 1 medium flocculation in front Absen sewage mittelkon 48.5 kung (%) 'Petroleum distillation. (%) ED concentration 2.4 in front 0.02 Absen FeCl ₃ 0.5 4.5 89.1 flocculation kung (%) 9.2 1st process 4.6 1.23 0.0 98.4 water part lime - 8th 73.9 electricity milk 17.5 3.9 2nd process 0.25 0.0 100 water part lime - 8th 22.4 4.5 73.7 electricity milk 0.0 Mischab lime - 8th 48.5 82.6 0.40 100 water 1 milk 3.4 0.03 Mischab polyethylene 8-10- ³ 8th 90.7 0.12 100 water 2 imine / lime (Lime 48.5 1st process milk milk) 12.5 1.23 0.03 97.6 water part polyethylene 8-10 " ³ 8th 93.0 electricity imine / FeCl ₃ (Lime 42.6 1st process milk) 3.1 1.23 0.05 97.6 water part Polyquat 20 / 4-ΙΟ " ⁴ 8th 70.7 electricity lime (Lime 11.1 1st process milk) 1.02 0.01 95.1 water part FeCI ₃ / AICI ₃ 0.1 / 0.1 6 72.1 electricity (KaIk- Mischab 0.24 95.8 water 1

milk)

Table 2 Wastewater

dosed milk of lime

m / l

2.:1. (7) - 10 Prozeßwas (8th) 20 serteilstrom 2: 1 (9) 40 mixture

set pH

untreated

pH

HTS

CSV Cr

g / i

ED

3.9

0.20

14.3

0.17

KH

mg / l

532

2. Process (1) 10 6-7 3.0 0.20 8.6 0.05 315 99 wasserteil- (2) 20 8-9 3.0 0.20 8.6 0.05 315 99 electricity (3) 40 10-11 3.0 0.20 8.6 0.05 315 99 1. process (4) 20 8th 5.7 0.02 23.0 0.41 965 297 wasserteil- (5) 30 9 5.7 0.02 23.0 0.41 965 297 electricity (6) 60 11 5.7 0.02 23.0 0.41 965 297

7-8 3.9 0.20 14.3 0.17 532 165 8-9 3.9 0.20 14.3 0.17 532 165

Continuation of Table 2

Wastewater after flocculation (residence time = 1 h)

clear phase CSV-Cr g / i KH mg / l FS mg / l CSV Cr-lowering bottom sludge HTS ED HTS 3.4 2.5 2.2 230 183 115 79 70 52 60.5 70.9 74.4 proportion of 1.20 1.01 0.94 0.62 0.52 0.47 (1) (2) (3) 0.04 0.02 0.02 18.9 16.3 19.6 840 955 605 290 194 185 17.8 29.1 53.9 23.5 27.6 33.8 0.85 1.02 1.84 0.75 0.85 0.84 (4) (5) (6) 0.03 0.02 0.04 10.2 6.6 5.3 472 396 320 141 132 114 28.7 53.8 62.9 8.5 17.3 25.8 0.82 0.97 1.27 0.60 0.67 0.62 (7) (8) (9) 0.06 0.03 0.04 12.7 24.6 39.1

The table shows that ingredients such as yeast cells, carbohydrates, fatty acids and petroleum distillate are bound in the flocculant.

Due to the flocculation process, the feed yeast content was reduced by 70-90%, carbohydrates by 35-65% and fatty acids by 30-45% in the process water.

After addition of the flocculant according to the invention, a spontaneous separation of the organic ingredients and the emulsified oil took place within a few minutes. Thereafter, the bottom sludge densified exponentially, this process after 15 minutes residence time was immaterial.

Claims (6)

Invention claim: 1. A process for the purification of waste water and process waters of microbiological protein extraction from petroleum distillate by means of chemical flocculation with conventional flocculants and pH influencing, characterized in that from the wastewaters and process waters of microbiological protein production in the pH range 3-11 simultaneously dissolved, colloidal and emulsified substances are continuously removed, which are then concentrated by known methods, such as filtration, ultrafiltration, separation or flotation, and recycled to the process of microbiological protein recovery. 2. The method according to item 1, characterized in that lime milk is used in the pH range 8-11. 3. The method according to item 1, characterized in that Lime / polydiallyldimethylammonium chloride or lime / polyethyleneimine mixtures at pH 8 are used. 4. The method according to item 1, characterized in that iron-III chloride or iron-III sulfate in the pH range 3-8.5 is used. 5. The method according to item 1, characterized in that iron-l chloride / polyethyleneimine mixtures in the pH range 6-8.5 are used. 6. The method according to item 1, characterized in that iron-III chloride / aluminum-III chloride mixtures are used in the pH range 5.5-8.