FR2595683A1 - PROCESS FOR THE BIOLOGICAL PURIFICATION OF ETHYLENE GLYCOL IN WASTEWATER - Google Patents

Abstract

THE INVENTION RELATES TO THE BIOLOGICAL PURIFICATION OF WASTE WATER CONTAINING HIGH CONCENTRATIONS OF ETHYLENE-GLYCOL. ACCORDING TO THE INVENTION, WASTE WATERS TO BE purified, CONTAINING ETHYLENE-GLYCOL, TRACE ELEMENTS, SOURCES OF PHOSPHORUS, NITROGEN AND A MICRO-ORGANISM OF THE ARTHROBACTER GENUS, ARE INTRODUCED; THE INDICATED MICRO-ORGANISM IS THEN CARRIED OUT AT A TEMPERATURE OF 20-35C UNTIL THE ETHYLENE-GLYCOL PURIFICATION IN THE RESIDUAL WATER. THE INVENTION MAKES IN PARTICULAR A BIOLOGICAL PROCESS OF WASTEWATER CONTAINING MORE THAN 2000 MGDM OF ETHYLENE-GLYCOL, OBTAINING A PURITY LEVEL OF 99.

Description

The invention relates to the biological purification of waste water at high

  ethylene glycol content aimed at

get rid of it.

  The claimed invention will find application in the extraction and transformation of natural sulphurous gases whose technological processes require the use of ethylene glycol and which are accompanied by

  the formation of waste water with an ethylene content

glycol exceeding 2000 mg / dm3.

  In gas processing plants, an aqueous solution of ethylene glycol at a concentration of 75-80% is used for the drying of the natural gas. The saturated ethylene glycol solution is subjected to regeneration by

  rectification with subsequent condensation and recycling.

  The waste water resulting from the regeneration contains ethylene glycol (in the majority of cases, in high

  concentrations - 2000 mg / dm3 and above) and

  traces (K +, Mg2 +, Zn2 +, Fe2 +, Mn2 +, Ca2 +, NO2, SO4).

  At the present time, waste water containing ethylene glycol at high concentrations is subjected either to a discharge in the absorbing groundwater without prior purification, which does not exclude the possibility of penetration of impurities into the groundwater. surface waters and under the bed, or are directed to incineration plants for the combustion of organic substances

  contained in the waste water, which pollutes the atmosphere.

  It is known that ethylene glycol at a concentration of 0.1 mg / dm3 is assimilated to phenol as a carbon source for microorganisms in activated sludge.

  (see kuniska-Goldfinger Wladyslava, Wlostowski Tadeusz.

  "Application of semi-continuous culture on membrane filters

  for the study of activated sludge bacteria "Acta microbiol.

pol., 1980, 29, No. 4, 407-412).

  Ethylene glycol at a concentration of not more than 10 mg / dm3 can be destroyed by the microorganisms of the genus Acinetobacter (see Watson G.K., Jones N. "The biodegradation of polyethylene glycols by sewage

  bacteria "Water Res., 1977, 11, No. 1, 95-100) and microorganisms.

  organisms of the genus Pseudomonas (see Fincher E.L., and

  Payne W.T. "Bacterial utilization of ether glycols". Appl.

  Microbiol. 1962, 10, pages 542-547). However, the use of microorganisms mentioned for the industrial purification of waste water is not possible, since they are not able to destroy

  high concentrations of ethylene glycol.

  A process for the biological purification of wastewater is known for liberating them from tributyl phosphate using activated sludge with the introduction of ethylene glycol at a concentration of up to 200 mg / dm in wastewater which, in this process is a co-oxidant of the main contaminant of waste water and simultaneously a source of carbon for microorganisms of activated sludge, and therefore it is itself subject to destruction (see the certificate of authorship). USSR No. 673616

published on July 15, 19791.

  The disadvantage of the known method lies in the impossibility

  the ability to ensure the destruction of high concentrations of ethylene glycol (over 200 mg / l), as the activated sludge of biological treatment plants perishes without supporting such a concentration of contaminating agent, and the purification process becomes impossible. Another disadvantage of the process is a poor efficiency of the process of biochemical destruction of impurities because of a prolonged delay

  prior adaptation of activated sludge (three weeks).

  It was therefore proposed to develop a purification process

  wastewater biology, in which micro-organism species with the power to destroy high concentrations of ethylene glycol

(more than 2000 mg / dm3).

  The solution is that in the purification process

  ethylene glycol in waste water, according to the present invention, trace elements, sources of phosphorus, nitrogen and a microorganism are introduced into the waste waters containing ethylene glycol. organism of the genus Arthrobacter, then the culture of the indicated microorganism is carried out at a temperature of 20-35 C until the purification of the ethylene glycol of the waste water. Thanks to the claimed invention, it has become possible to purify, by a biological method, waste water containing more than 2000 mg / dm 3 of ethylene glycol, by obtaining

a purity level of 99%.

  It is advantageous, in accordance with the claimed invention, to use Arthrobacter simplex 667, Arthrobacter variabilis 667 strains deposited at the Central Museum as microorganisms of the genus Arthrobacter.

  promyshlennych microorganismov Vsesojuznogo nauchno-

  issledovatelskogo instituta genetiki i selektsii promyshiennych microorganismov or the strains Arthrobacter species 126,

  Arthrobacter species 127, deposited at the Museum of Micro-

  destructive organisms Instituta kolloidnoi khimii i khimii

  vody im.A.V. Dumanskogo Akademii Nauk Ukrainskoi, USSR.

  It is rational for the purification of ethylene glycol-containing waste water at a concentration exceeding 4000 mg / dm3, in accordance with the claimed invention, to introduce, in the waste water, as a source of nitrogen and ethylene glycol cooxidant, diethanolamine in the ratio of 1: 4-5 respectively, as well as

  than a microorganism of the genus Pseudomonas.

  For the purification of wastewater containing ethylene glycol and diethanolamine, it is advantageous, in accordance with the claimed invention, to maintain the

  ratio of diethanolamine to ethylene glycol at 1: 4-5.

  Other purposes and advantages of the invention will be better

  understood from the description of the claimed process

  of the biological purification of the ethylene glycol in the waste water that will follow, several embodiments. In the claimed invention, new

  bacteria of the genus Arthrobacter capable of destroying

  ethylene glycol at high concentrations, in particular from 2000 mg / dm3 and up to. its reduced content in wastewater equal to 70-100 mg / dm3. The bacteria of the genus Arthrobacter are in the form of mobile rods (on day 3 coccus), they have a Gram-positive staining. They ferment the

  lactose, xylose, fructose, form the hydrogen sulfide

  gene and ammonia, give good growth on 2% solutions of sodium chloride and on solutions

7% glycerin.

  Efficient waste water treatment at high concentrations of ethylene glycol (2000 mg / dm3) can only be achieved with the use of the following Arthrobacter: Arthrobacter simplex 667, Arthrobacter variabilis 667 strains, deposited at the Central Museum promyshlennych microorganismov Vsesojuznogo nauchno-issledovatelskogo institute genetiki i selektsii promyshiennych micro-organismov, or strains of Arthrobacter species 126, Arthrobacter species 127, deposited in the Museum of destructive microorganisms Instituta kolloidnoi khimii i khimii vody im. A.V. Dumanskogo

Akademii Nauk Ukrainskoi USSR.

  The Arthrobacter species 126 and Arthrobacter species 127 strains are selected from the activated sludge in the water flow. Both strains during their growth in a liquid medium with carbon assimilate, saccFarose, fructose, arabinose, insulin, glycerine, inosite, sorbitol, mannite, glucose, duality, raffinose , lactose and rhamnose. The strains indicated do not grow on xylose or maltose. They grow

  in the form of film on the surface of liquid media.

  The strain Arthrobacter species 126 assimilates weakly

galactose.

  Arthrobacter species 127 does not assimilate galactose.

  Arthrobacter species 126 is urease positive.

  Arthrobacter species 127 is urease-negative.

  Both cultures have a creamy color on peptone agar

meat.

  On synthetic media, Arthrobacter species 126 has a cream color and Arthrobacter strain

species 127 has an orange color.

  During the growth of these bacteria, the morphology of the cells with formation of the coccoid, digested and V forms is observed. The claimed process for the biological purification of wastewater consists in the introduction into these waters containing

K 2+ 2+

  ethylene glycol, trace elements (K +, Mg2 + Zn2 +

2 + 2 + 2+ - 2-

  Fe2 +, Mn2 +, Ca2 +, NO2, SO4), phosphorus sources, for example disubstituted sodium or potassium phosphate, and nitrogen sources, for example ammonium nitrate, thus ensuring a ratio of carbon , nitrogen and phosphorus of 100: 5: 1 respectively, necessary for the

vitality of microorganisms.

  One of the abovementioned strains is then introduced into the waste water, thus ensuring a density

  seeding material of at least 108 cells / ml.

  The specified microorganism is cultured at a temperature of 20-35 C until the ethylene glycol is purified in the waste water, during

about 24-48 hours.

  When treating waste water to a certain

  greater than 4000 mg / dm3 of ethylene glycol, before introduction

  In microorganisms in water, an oxidizing agent, diethanolamine, is added in an amount that provides a ratio of diethanolamine to ethylene glycol of 1: 4-5. The

  Diethanolamine is also a source of nitrogen.

  However, it is then necessary to additionally introduce, into the wastewater to be purified, microorganisms of the genus Pseudomonas. They are preferably introduced in a quantity ensuring a ratio between the

  microorganisms of the genus Arthrobacter and microorganisms

  organisms of the genus Pseudomonas equal to 1: 5.

  Any microorganisms of the genus Pseudomonas, capable of destroying diethanolamine at a concentration greater than 1000 mg / dm3 in the presence of ethylene-

  glycol at a concentration greater than 2000 mg / dm3.

  In a gas processing plant, for the purification of a natural gas from the sulfurous components (hydrogen sulphide, mercaptans), an aqueous solution of diethanolamine at a concentration of 25-30% is used. The solution

  Saturated diethanolamine is subjected to thermal desorption.

  for the removal of sulfur compounds, then it undergoes purification on activated carbon in special adsorbers and is returned to the production cycle. The waste water resulting from regeneration contains

  up to 10000 mg / dm3 of diethanolamine.

  They must also undergo purification.

  The claimed invention makes it possible to purify the waste water, containing ethylene glycol, with diethanolamine, the diethanolamine then acting as a cooxidant for the ethylene glycol and that of the nitrogen source, itself even being subjected to microbiological destruction. However, it is necessary for this purpose to maintain the ratio between diethanolamine and ethylene glycol, according to the invention,

within the limits of 1: 4-5.

Example 1

  Biological purification is carried out

  Duaries having the following composition, in mg / dm3: ethylene glycol -3300

K + - 700

  Mg2 + - 240 Zn2 + - 2.1 Fe2 + - 16 Mn2 + - 2.1 Ca2 - 8.8

NH4 + - 4.3

po4 3-

4 - 0.3

NO? - - 0.06

SO - 2-

4 - 80.0

pH of waste water: 8 to 8.5

  Chemical consumption of oxygen (mg / dm3) = 5100.

  In the waste water, additionally an additive containing ammoniacal nitrogen (150 mg / dm3 of NH4NO3) and phosphorus (350 mg / dm3 of Na2HPO4) is introduced, ensuring the carbon-nitrogen-phosphorus ratio of 100: 5: 1

  necessary for the vitality of the micro-organisms used.

  The waste water is introduced into the waste water.

  Arthrobacter simplex 667 organism and the biological purification of the water in a bioreactor (volume of 83 dm3) is undertaken during the continuous culture of the microorganisms, during 10 days under aerobic conditions. The starting density of the inoculum is

3 -1

  g / dm3, the speed of the dilution is 0'1, 1 hour1, the temperature is 25 C, the consumption is 1 dm3 / hour, which ensures a dissolved oxygen content

in water of at least 5-7 mg / dm3.

  To determine the growth curve, microorganisms of the genus Arthrobacter are seeded at a density of 108 microl / cm 3 in a 100 ml volume nutrient medium, prepared on piped water, containing ethylene glycol and cultured. in

  Erlenmeyer flasks in periodic mode for 24-hours.

  The values of the chemical consumption of oxy-

  gene by the known technique of the technological control of the work of the purification works, the ethylene glycol is determined by photometric and gasochromatographic way,

  the purity of the waste water with respect to

  ethylene glycol is calculated from the reduced concentration of ethylene

  alycol as a percentage of its initial amount. Purity indices

  waste water are summarized in the table below.

Example 2

  The ethylene glycol is purified in waste water under conditions similar to those

  described in Example 1, however, as a micro-

  organisms, the strain Arthrobacter variabilis 667 is used. The purity indices of the wastewater are

summarized in the table below.

Example 3

  The ethylene glycol is purified in waste water under conditions similar to those indicated in Example 1. However, the starting concentration of ethylene glycol is 4600 mg / dm3; we introduce

  additionally, in waste water, dietary

  In a concentration of 1150 mg / dm3 as a cooxidant of ethylene glycol and a single nitrogen source, and as a microorganism, Arthrobacter species 126 and bacteria of the genus Pseudomonas are used. The purity indices of waste water are given in the table

Example 4

  The purification of ethylene glycol is carried out in waste water under conditions similar to those described

  in Example 3. However, as a cooxidant of ethylene,

  ethylene glycol and a single nitrogen source, diethanolamine is used at a waste water content of 920 mg / dm3, and as microorganisms of the genus

  Arthrobacter, the strain Arthrobacter species 127 is used.

  The purity indices of the wastewater are

summarized in the table below.

Board

  _______________________________________________________________

  Report Quality Indices of Waste Waters Example ethylene- before purification (mg / dm3)

  No. glycol: - - - - - - - - - - - - - - - - - - -

  Diétha- Concentra- Consumption- Concentration

  nolamine tion in chi- dietha-

  ethylene nolamine glycol oxygen

1 2 3 4 5

1 - 3300 5100 -

2 - 3300 5100 -

3 4: 1 4600 8300 1150

4 5: 1 4600 8200 920

  __________________________________________________________________________ _

  Table (continued) Example Water Quality Index Purity Rate, Purified Waste No. (%) (mg / dm3)

  concentrate-consumption-ethylene-diethanol

  tion in ethylene glycol

  enol-Glycol in amine diol amine-02 amine

1 6 7 8 9 10

1 270 - 405 92.9 -

2,250 - 395 93.4 -

3 100 15 150 97.8 98.9

4,100 10,150 97.8 99.1

  _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Claims (4)

R E V E N D I C A T I 0 N S   1. - Process for the biological purification of ethylene   glycol in waste water, characterized in that in waste waters containing ethylene glycol, and trace elements, sources of phosphorus, nitrogen and a microorganism of the genus Arthrobacter are introduced, then carries out the cultivation of the microorganism indicated in   a temperature of 20-35 C until the purification of ethylene- glycol in waste water.   2. - Method according to claim 1, characterized in that as a microorganism of the genus Arthrobacter is used the strain Arthrobacter simplex 667, Arthrobacter variabilis 667, deposited in the Central Museum promyshiennych microorganismov Vsesojuznogo nauchno-issledovatelskogo instituta genetiki i selektsii promyshlennych microorganismov or strains of Arthrobacter species 126 and 127 deposited   at the Museum of destructive microorganisms Instituta Kolloid-   noi khimii i khimii vody im.A.V. Dumanskogo Akademii Nauk Ukrainskoi, USSR.   3. - Process according to any one of the claims   1 or 2, characterized in that as a source of nitrogen and ethylene glycol cooxidant, is introduced, in the   wastewater, diethanolamine with an ethylene-   glycol: diethanolamine respectively of 1: 4-5, and additionally introduced a microorganism of the genus Pseudomonas.   4. - Method according to claim 3, characterized   in that in the case of using waste water con-   in addition to the diethanolamine, the diethanolamine: ethylene glycol ratio of 1: 4-5 is maintained   the process of sewage treatment.