FR2770227A1 - Composition for biological treatment of waste water especially from paint spray cabins - Google Patents

Abstract

Composition for biological treatment of waste waters and sludges comprises: (a) at least one mixture of specialised bacteria containing "a micro-organic base of the animal kingdom and a phyto-organic base"; (b) a mixture of bacteria with a broad activity spectrum immobilised on a porous and flocculant mineral carrier; and (c) nutrients. Preferably component (a) is present in an amount of at least 10<7> cells/g and comprises 80% "micro-organic base" and 20% "phyto-organic base". Component (b) is present in an amount of 10<4> cells/g. The "micro-organic base" is a mixture of Bacillus subtilis, Pseudomonas putida, Pseudomonas cepacia, Pseudomonas fluorescens and Phanerochaete chrysosporium. The "phyto-organic base" is a mixture of Rhizopus arrhizus and Disporotrichum denorphoporum. The mineral carrier comprises 50% CaCO3 and 50% bentonite. The nutrients are nitrogen, phosphorus and trace elements.

Description

BIOLOGICAL COMPOSITION FOR CLEANING EFFLUENTS
AQUEOUS AND SLUDGE AND ITS PROCESSING PROCESS
AND SOWING.

The invention relates to the technical sector of the treatment of liquids containing polluting substances of the mineral and / or organic type.

The invention finds a particularly advantageous application, which should not however be considered as strictly limiting, for the treatment of the washing water circulating in the water curtain painting booths.

Generally, a painting booth constitutes a workstation partially closed at the rear and on the sides, the product or the like to be painted being placed opposite the rear face. The spraying of paint as such is carried out manually or robotically. The rear face of the cabin is designed to allow the circulation of a film of water. The circulation water is pumped into a receiving tank, operating in a closed circuit, and flows along the panel or panels which constitute the rear face of the cabin. The water makes it possible to capture the particles of products not fixed by the part, during the application of the paint. The circulating water is therefore loaded with solvent, pigments, and binders and other fillers, characteristic of paints. We thus find the mineral part of the formulation (mineral fillers and pigments) as well as the organic part (resins, binders and organic fillers) and, to a lesser extent, the solvent part (organic).

This results in a progressive loading of this washing water as well as a clogging of all the equipment of the cabin, among which we can cite the water curtain, the chutes, the receiving tank, the pump, the pipes, the baffles ...

In an attempt to remedy this fouling which is very rapid and proportional to the quantity of paint sprayed, chemical additives of the flocculant type are generally used, the function of which is to make the product lose their sticky appearance, and to agglomerate them either at the bottom , or on the surface of the receiving tray. The flocculants are distributed by a metering pump or put manually. It is therefore necessary to collect the suspended matter which appears in the water of the collecting tank, in order to evacuate the recovered flocs daily, in order to destroy them in specific incineration installations.

Collecting and skimming the flocs collected by coagulating chemicals requires periodic water change as well as sludge disposal. This requires time, and the presence of recovery containers as close as possible to the workstation.

It is also observed that the flocculants intervene only during the liquid phase and have no cleaning action on the parts fouled by the accumulations of polluting products. It is therefore necessary in some cases to remove the removable parts of the water curtain, for cleaning and cleaning to keep the cabin its ventilation qualities.

It is understood that this intervention can have harmful consequences on production times.

The object of the invention is to remedy these drawbacks in a simple, safe, efficient and rational manner.

The problem which the invention proposes to solve is to use a work station and its circulation water to degrade by means of a suitable population of microorganisms all the organic substances contained in paints and others, and recovered in the water film.

In fact, the increasingly precise knowledge of bacterial metabolisms and their use in purification makes it possible to overcome certain prejudices about the potential and reliability of biological techniques.

Generally, the basic ratio used to qualify the potentialities of a biological system as a function of industrial applications was limited to a level of chemical oxygen demand, less than or equal to three times the biological oxygen demand over five days. However, it appeared that microorganisms selected for their tropism to degrade certain molecules in a conditioned medium, can operate much more complete and more extensive transformations leading to an almost total decomposition of the pollutants into carbon dioxide water and nitrogen gas.

It is also known that biological treatments use microorganisms which develop in the medium to be purified, consuming the organic material. This consumption can take place in the presence or absence of oxygen so that the biological processes are aerobic or anaerobic. According to the invention, the biological treatment process is of the aerobic type.

According to the invention, taking into account the problem to be solved, which is to be able to degrade all the organic substances that circulating water may have, by means of a suitable and selected population of microorganisms, a composition has been designed and developed. organic, which includes:
- at least one mixture of specialized bacteria containing a micro-organic base from the animal kingdom and a phyto-organic base,
- a mixture of bacteria with a broad spectrum of action fixed on mineral supports of the porous type and flocculants to constitute an active biomass,
- elements of balance in the form of nutrients.

The micro-organic base is present in a proportion of approximately 80% relative to the phyto-organic base present in proportions of approximately 20%.

Specialized bacteria have a titer of at least 107 germs per gram. Bacteria with a broad spectrum of action have a germ concentration per gram of 104.

The bacterial products selected for the biological composition, under the conditions indicated above, are formulated from non-pathogenic microorganisms, as defined by the AFNOR NFX 42.040 standard of March 1990, the decree 94352 of May 4, 1994 and the order of July 10, 1994. These microorganisms belong to group 1, as defined by article R23 l -61 of decree 94-352 and are non-genetically modified wild strains.

Under these conditions, the micro-organic base of the animal kingdom consists mainly of species derived from the following germs, in equal or substantially equal proportions
- Bacillus subtilis
- Pseudomonas putida,
- Pseudomonas cepacia
- Pseudomonas fluorescens,
- Phanerochaete chrysosporium
while the phyto-organic base consists mainly of equal or substantially equal parts, of
- Rhizopus Arrizus,
- Disporotrichum denorphoporum,
The mineral supports are calcium carbonates in proportions of approximately 50% and clays of the bentonite type in proportions of approximately 50%.

Calcium carbonates are selected for their very large developed surface area taking into account their microporous character, while clays are selected taking into account their ability to act as a unifier and decolorizer.

The nutrient balance elements are nitrogen, phosphorus, trace elements in particular magnesium.

The industrial application of the biological composition according to the characteristics of the invention, in particular for the purification of aqueous effluents and of sludge, requires, as will be indicated in the remainder of the description, to comply with certain rules, in particular at the level of seeding program, control of balance parameters (nitrogen and phosphorus) and the initial supply of nutrients essential for bacterial metabolism.

As indicated, the invention finds a particularly advantageous application for the biological treatment of water curtain painting booths, as emerges from the figures of the appended drawings, in which:
FIG. 1 is a perspective view of an exemplary embodiment of a water curtain painting booth.

FIG. 2 is a schematic sectional view showing the operating principle of a water curtain painting booth, and showing the application of the biological composition according to the invention.

In known manner, a painting booth essentially comprises a bottom panel (1) arranged to create a film of water opposite which the object to be painted will be placed. The water is drawn by means of a pump (2) from a recovery tank (3) to be sent to the upper level of the bottom (1), in order to subject it to a continuous circulation of water. A closed circuit is therefore obtained for the circulation of water, thus ensuring a continuous sweeping of the bottom (1) of the cabin which constitutes a water curtain.

These arrangements are not described in detail because, on the one hand, they do not form part of the specific object of the invention and, on the other hand, they are perfectly known to a person skilled in the art.

According to the invention, it appeared important to ensure good oxygenation of the liquid into which the biological composition will be introduced.

For example, in the case of a spray booth of the type shown in figure 1, it is necessary to provide in the bottom of the recovery tank (3), below the water curtain (1), a ramp ( 5) air distribution supplied, for example, by a 0.5 to 1 bar booster. It is important that the dissolved oxygen level is at least 2 mg / l of dissolved oxygen in phase when the water is no longer circulating and at 6 mg / l +0.2 in
-0 work sequence.

It should be noted, in the case of a large-scale recovery tank, which is fitted to certain painting booths, that the oxygenation can be carried out in a natural way. It is simply checked that during the stop sequences, the medium is not in anoxia (absence of oxygen).

Before describing the program for seeding the biological composition, it is recalled that the latter comprises at least a mixture of specialized bacteria containing a micro-organic base and a phyto-organic base, and a mixture of bacteria with a broad spectrum of action, fixed on mineral supports of the porous and flocculating type to constitute an active biomass.

The specialized bacteria which are selected to present a titration of at least 107 in germs per gram, consist mainly of species derived from the following germs:
- Bacillus subtilis,
- Pseudomonas putida,
- Pseudomonas cepacia,
- Pseudomonas fluorescens,
- Phanerochaete chrysosporium.
in order to constitute the micro-organic base of the animal kingdom and by the following species:
- Rhizopus Arrizus,
- Disporotrichum denorphoporum,
in order to constitute the phyto-organic base.

It should be noted that the different species, both for the microorganic base and for the phyto-organic base, are introduced in equal or substantially equal proportions, but the exact nature of the ready-to-use products to be degraded can vary this rule.

The microorganisms meeting the above characteristics are fixed on mineral supports in hygroscopic powders. These supports can be zeolhite rocks, bentonites, calcium carbonates of marine origin. These different products are known and referenced.

If we consider the inoculation program as such, after checking the oxygen present in the collecting tank (3), and after checking the pH level which will be in a neutral zone, between 7, 5 and 8.5 approximately, the establishment of the biological composition is carried out in the forms and chronological conditions defined below.

Bacteria specializing in compounds that are difficult to degrade are awakened in water between 20 and 350C for lu + 30. To achieve this awakening, one can use a reactor providing stirring and oxygenation for the desired time and temperature. This awakening can also be carried out manually, at a rate of 50 g of the mixture considered in one liter of water at temperature, by stirring this mixture, three or four times during the awakening time. If the composition uses more than one mixture of specialized bacteria, the latter are awakened separately before their introduction into the recovery tank or other containing the water. Likewise, their bacterial count must be at least 107 bacteria per gram.

As regards bacteria with a broad spectrum of action, and associated with a higher proportion of starting nutrients, the latter are introduced directly and without awakening into the collection tank (3). Their bacterial count is 104 in germs per gram.

The equilibrium elements, in the form of nutrients, nitrogen, phosphate and trace elements are also introduced directly into the tank (3).

The nitrogen-phosphorus ratio is 1 0.5 mg / l for phosphorus and 6 + 2 mg for nitrogen compared to a value of 200 mg / l of raw chemical oxygen demand of a liquid sample taken at cruising speed after the weekly cabin downtime. This sample of approximately ll water is taken in the center of the recovery tank, very substantially 2cm below the surface of the water. The equilibrium is reestablished with commercial technical urea and disodium anhydrous phosphate also commercially available.

It is recalled that 2.35 g of urea provide lg of nitrogen, while 5g of anhydrous disodium phosphate provide lg of phosphorus.

In the case of an application of the biological composition to the treatment of water circulating in a paint booth, the maintenance for this application can be explained as follows:
At the start and during the first eight days, the circulating water in the cabin becomes charged with paint particles so that the recovery tank (3) has floating plates of non-degraded products on the surface. At this stage, the work of bacterial degradation is not yet optimized. These floating plates disappear after about ten days, the transformation into organic matter being complete. After the inoculation program as described, a dosage of specialized and awakened bacteria separately, of fixed bacteria, and of nutrients corresponding to a day of the inoculation program is introduced each week. Every three months, a liter of water is taken from the tank before the start of a weekly work cycle. This sample is taken in the center of the tank approximately 2cm from the surface.

Reference is made to the table below, which gives an example of the inoculation and application program of the biological composition for approximately lm3 of water, considering that 25kg of paint are sent daily into the water curtain of the cabin. paint. Remember that 25kg of paint called in the profession (Ready to Use P.A.E.product) recovered in circulating water corresponds to 50kg of paint product applied by means of a spray gun at the workstation.

In this table:
- Cl corresponds to a mixture of specialized bacteria with a microorganic base from the animal and phyto-organic kingdom,
- C2 corresponds to a mixture of specialized microorganic bacteria from the animal and phyto-organic kingdom,
- C3 corresponds to a mixture of bacteria with broad action spectra, less concentrated on porous supports associated with nutrients housed in the pores of the substrate,
- N corresponds to the element of equilibrium in the form of a nutrient.

- P corresponds to a sample,
- PHD corresponds to disodium phosphate,
- R corresponds to the transition to an awakening reactor,
- UT corresponds to technical urea
- V corresponds to a visual check.

In this example, the biological composition is therefore produced from two mixtures of specialized bacteria.

<tb>

<SEP> DAYS <SEP> DAYS <SEP> CONTROL <SEP> QUANTITIES <SEP> IN <SEP> GRAMS
<tb> CALENDER <SEP> OPENABLE <SEP> BY <SEP> APPLICAnON <SEP>
<tb><SEP> R <SEP> R
<tb><SEP> 1 <SEP> 1 <SEP> C1 = 50 <SEP> C2 = 50 <SEP> C3 = 100 <SEP> N = 800 <SEP> UT = 25 <SEP> PHD = 10
<tb><SEP> 2 <SEP> 2 <SEP> Cl <SEP> = 50 <SEP> C2 = 50 <SEP> C3 = 200 <SEP> N = 300 <SEP> UT = 50 <SEP> PHD = 20
<tb><SEP> 3 <SEP> 3 <SEP> Cl = 50 <SEP> C2 = 50 <SEP> C3 = 200 <SEP> N = 300 <SEP> UT = 50 <SEP> PHD = 20
<tb><SEP> 4 <SEP> 4 <SEP> C1 = 80 <SEP> C2 = 80 <SEP> C3 = 800 <SEP> N = 500 <SEP> UT = 100 <SEP> PHD = 50 <SEP>
<tb><SEP> 5 <SEP> 5 <SEP> p <SEP>
<tb><SEP> 6
<tb><SEP> 7
<tb><SEP> 8 <SEP> 6 <SEP> P <SEP> C1 = 80 <SEP> C2 = 80 <SEP> C3 = 800 <SEP> N = 500 <SEP> UT = 100 <SEP> PHD = 50 <SEP>
<tb><SEP> 9 <SEP> 7 <SEP> C1 = 80 <SEP> C2 = 80 <SEP> C3 = 800 <SEP> N = 500 <SEP> UT = 100 <SEP> PHD = 50 <SEP>
<tb><SEP> 10 <SEP> 8
<tb><SEP> he <SEP> 9
<tb><SEP> 12 <SEP> 10 <SEP> V
<tb><SEP> 13and14 <SEP>
<tb><SEP> 15 <SEP> 11 <SEP> P <SEP> C1 = 80 <SEP> C2 = 80 <SEP> C3 = 800 <SEP> N = 500 <SEP> UT = îOO <SEP> PHD = 50 <SEP>
<tb><SEP> 16 <SEP> 12
<tb><SEP> 17 <SEP> 13
<tb><SEP> 18 <SEP> 14
<tb><SEP> 19 <SEP> 15 <SEP> V
<tb><SEP> 20 and 21
<tb><SEP> 22 <SEP> 16 <SEP> P <SEP> to <SEP> from <SEP> of <SEP> 16 <SEP> working day <SEP><SEP> and <SEP> 1 <SEP> week-long <SEP> on <SEP> Monday
<tb><SEP> Cl <SEP> = 80 <SEP> C2 = 80 <SEP> C3 = 300 <SEP> UT3500 <SEP> PHD = 200 <SEP>
<tb>
Remember that the mixtures of specialized bacteria (C1 and C2) are awakened separately in a reactor (1 hour to 1 hour 30 minutes), while the bacteria (C3), nutrients (N), technical urea (UT) and disodium phosphate ( PHD) are introduced together directly into the tank.

Note that in cases of heavy loads, urea and phosphate will be put in twice (Monday and Wednesday). The weekly dosages remain the same.

The characteristics of the invention, both at the level of the biological composition as such, and of its method of application, make it possible to overcome the prejudices normally accepted as regards biological treatments.

Indeed, according to the invention, it appears that the ratio of the chemical oxygen demand to the biological oxygen demand is 8/1, which should prohibit conventional biological work primarily addressing the biological oxygen demand. . The pollutant load is both very rapid and very high, during the period of application of the paint, thus creating, in the receiving environment, a level of harmfulness which could be unsuitable for any action of microorganisms.

According to the invention, these two problems do not meet if one considers the know-how as regards the preparation and the introduction of the inocolum during the critical period of inoculation. At cruising speed, the perreinity of performance is directly linked to the periodic control elements making it possible to correct and therefore optimize the essential parameters which are dissolved oxygen, pH, total nitrogen dosage in relation to total phosphorus, overload in suspended matter, the accidental presence of biocides.

It is also observed that the sludge recovered at the last stage in lesser quantity constitutes mineral fillers which can find a less expensive and more secure disposal or reuse process.

As indicated, the biological composition, according to the characteristics of the invention and according to its inoculation process, finds a particularly advantageous application for the treatment of runoff water from a paint booth. On a private basis, tests were carried out on all solvent and water-soluble paints in order to verify the validity of the process applying the biological composition and its inoculation process as defined. It appears that at the end of the degradation cycle, only the mineral part of the pigments and fillers contained in the paints appears in the bottom of the tank. In weight load, this ranges from 6 to 20% depending on the type of paint, and depending on the dry matter. For the organic part, this results in a complete transformation leading to the final CO2-H20 stage.

The degradation capacity is expressed by a performance index represented by the quantity of ready-to-use paint passing through a curtain of water collected in a lm3 tank. Tests carried out over a period of 24 months have shown a degradation of 99% of the organic for 25kg of paint per day, absorbed on a water curtain coupled with a lm3 recuperator tank. This paint booth, which operates 8 hours a day and 5 working days a week, uses 50 kg of P.A.E. per day.

Reference is made to FIG. 2 which shows, by a view of a purely schematic nature, an example of an installation for the application of the biological treatment process to a spray booth with water streaming. In this regard, all power control and other functions can be fully automated.

The advantages emerge clearly from the description, in particular we underline and recall:
- permanent self-cleaning of the workstation,
- the quality of the result obtained,
- the elimination of tasks related to cleaning as such,
- lowering of sludge production as a function of the percentages of organic matter present in the paints.

Claims (31)

CLAIMS -1- Biological composition for purifying aqueous effluents and sludge, characterized in that it comprises: - at least one mixture of specialized bacteria containing a microorganic base from the animal kingdom and a phyto-organic base, - a mixture of bacteria with a broad spectrum of action fixed on mineral supports of the porous type and flocculating to constitute an active biomass, - elements of equilibrium in the form of nutrients. -2- Composition according to claim 1, characterized in that the specialized bacteria have a titration of at least 107 germs per gram, the micro-organic base being present in a proportion of 80% relative to the phyto-organic base present in proportions of about 20%. -3- Composition according to claim 1, characterized in that the bacteria with a broad spectrum of action has a germ concentration per gram of 104. -4- Composition according to claim 1, characterized in that the micro-organic base is a mixture mainly made up of species from the following genera: - Bacillus subtilis, - Pseudomonas putida, - Pseudomonas cepacia, - Pseudomonas fluorescens, - Phanerochaete chrysosporium. -5- Composition according to Claim 1, characterized in that the phyto-organic base is a mixture of the following strains: - Rhizopus Arrizus, - Disporotrichum denorphoporum, -6- Composition according to Claim 1, characterized in that the mineral supports are calcium carbonates in proportions of about 50% and clays of the bentonite type in proportions of about 50%. -7- A composition according to claim 1, characterized in that the nutrient balance elements are nitrogen, phosphorus, trace elements. -8- Process for the implementation of the composition according to any one of claims 1 to 7 in a tank for collecting the circulating effluent, characterized in that: - the mixture or mixtures of specialized bacteria are separately awakened , - we introduce, after awakening, the mixture (s) into the tank, - we introduce the bacteria with a broad spectrum of action directly, - we introduce the nutrient balance elements directly. -9- The method of claim 8, characterized in that separately awakens the mixture or mixtures in water between substantially 20 and 350C for substantially 1 hour +301 by performing a stirring and oxygenation operation. - 10- The method of claim 8, characterized in that the nitrogen phosphorus ratio is 1+ mg / l for phosphate and 6 +2 mg / l for nitrogen for 200 -0 +2 mg / l of demand chemical in raw oxygen. -l 1- A method according to claim 9, characterized by a pH of the water between 7.8 and 8.5. -12- The method of claim 8, characterized in that the medium is oxygenated to develop and maintain an aerobic population. -13- The method of claim 8, characterized in that the equilibrium nutrients are introduced each week into the tank before start-up at a rate of lkg per lm3 of circulating water. -14- The method of claim 8, characterized in that the introduction of the composition for lm3 of circulating water receiving 25 kg / day of organic matter is carried out in the following proportions: 1st day: 50 g of a mixture of specialized bacteria Cl openable 50 g of a mixture of specialized bacteria C2 100 g of a mixture of C3 broad spectrum bacteria 300 g of nutrients 25 g of technical urea 10 g of disodium phosphate 2nd day: 50 g of a mixture of specialized Cl bacteria awakened in a reactor openable 50 g of a mixture of specialized C2 bacteria awake in a reactor 200 g of a mixture of C3 broad spectrum bacteria 300 g of nutrients 50 g of technical urea 20 g of disodium phosphate 3rd day: 50 g of a mixture of specialized bacteria Cl openable 50 g of a mixture of specialized bacteria C2 200 g of a mixture of C3 broad spectrum bacteria 300 g of nutrients 50 g of technical urea 20 g of disodium phosphate 4th day: 80 g of a mixture of specialized bacteria Cl openable 80 g of a mixture of specialized bacteria C2 800 g of a mixture of C3 broad spectrum bacteria 500 g of nutrients 100 g of technical urea 50 g of disodium phosphate 6th day: 80 g of a mixture of specialized bacteria Cl openable 80 g of a mixture of specialized bacteria C2 800 g of a mixture of C3 broad spectrum bacteria 500 g of nutrients 100 g of technical urea 50 g of disodium phosphate 7th day: 80 g of a mixture of specialized bacteria Cl openable 80 g of a mixture of specialized bacteria C2 800 g of a mixture of C3 broad spectrum bacteria 500 g of nutrients 100 g of technical urea 50 g of disodium phosphate From the 1 6th working day, once a week on Monday at start-up: 80 g of a mixture of Cl specialized bacteria 80 g of a mixture of C2 specialized bacteria 300 g of a mixture of C3 broad-spectrum bacteria 500 g of technical urea 200 g of disodium phosphate - 15 Application of the composition, as defined according to any one of claims 1 to 7, to a painting booth with water circulation having a curtain or said water circulating recovered in a tank subjected to a natural oxygenation action. or forced.