FR2694706A1 - Coagulation flocculation process with multi-speed agitation - Google Patents

Coagulation flocculation process with multi-speed agitation Download PDF

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Publication number
FR2694706A1
FR2694706A1 FR9308133A FR9308133A FR2694706A1 FR 2694706 A1 FR2694706 A1 FR 2694706A1 FR 9308133 A FR9308133 A FR 9308133A FR 9308133 A FR9308133 A FR 9308133A FR 2694706 A1 FR2694706 A1 FR 2694706A1
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duration
approximately
gradient
stirring step
during
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FR2694706B1 (en
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Bottero Jean-Yves
Lartiges Bruno
Suty Herve
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Arkema France SA
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Elf Atochem SA
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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
    • B01F23/50—Mixing liquids with solids
    • B01F23/51—Methods thereof
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
    • C02F1/5245—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents using basic salts, e.g. of aluminium and iron

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  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Dispersion Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Separation Of Suspended Particles By Flocculating Agents (AREA)

Abstract

Coagulation-flocculation of suspensions comprises cycles of fast and slow agitation steps with average velocity gradients of 300-1000 per sec for 30-200 sec. and 40-100 per sec for 5-40 min. The fast agitation is at 450 per sec, esp. for 180 sec. The slow agitation is at 85 per sec, esp. for 30 min. The coagulant is FeCl3, polyaluminium chloride and/or Al2(SO4)3. The pH of the suspension is 5-9 (5.5-8.5). The velocity gradient of the fast agitation step is increased in each successive cycle, esp. by at least 2.25 per sec. The duration of each these steps is constant. The velocity gradient of the slow agitation step and its duration in each cycle stays constant.

Description

NOUVEAU PROCEDE DE COAGULATION-FLOCULATION
La présente invention a pour objet un nouveau procédé de coagulation-floculation et se rapporte plus particulièrement à un procédé permettant l'obtention d'une cohésion des flocs issus d'une suspension agrégative.NEW COAGULATION-FLOCCULATION PROCESS
The present invention relates to a new method of coagulation-flocculation and relates more particularly to a method for obtaining cohesion of the flocs from an aggregative suspension.

Les procédés de coagulation-floculation sont largement utilisés dans de nombreux types d'industries nécessitant des séparations de milieux formés de phases susceptibles d'être séparées, notamment de boues. Ces procédés sont caractérisés par deux étapes principales. La première étape est la floculation qui est l'agrégation des suspensions colloïdales sous l'effet, d'une part, de la double couche électrique (constituée de la surface chargée électriquement et d'une distribution de charge compensatrice dans le milieu) et, d'autre part, d'un agent de floculation ou coagulant. Cet agent, typiquement un électrolyte ou un polymère, tel que polyacrylamide et polychlorure d'aluminium, crée des pontages favorisant la coalescence, i.e. la floculation. Les particules ainsi obtenues sont ensuite soumises à une coagulation, qui est la collision provoquée entre lesdites particules.Généralement, la collision est générée par un mouvement d'origine mécanique, on parle alors de coagulation orthocinétique. Coagulation-flocculation processes are widely used in many types of industries requiring separation of media formed from phases capable of being separated, in particular from sludge. These processes are characterized by two main stages. The first stage is flocculation which is the aggregation of colloidal suspensions under the effect, on the one hand, of the electric double layer (consisting of the electrically charged surface and a distribution of compensating charge in the medium) and, on the other hand, a flocculating or coagulating agent. This agent, typically an electrolyte or a polymer, such as polyacrylamide and polychloride of aluminum, creates bridges promoting coalescence, i.e. flocculation. The particles thus obtained are then subjected to coagulation, which is the collision caused between said particles. Generally, the collision is generated by a movement of mechanical origin, this is called orthokinetic coagulation.

La solution contenant les flocs ainsi obtenus est ensuite filtrée, généralement par filtration sur support. Lors de cette opération, il se pose de nombreux problèmes, dont deux principaux. Le premier est le manque de cohésion des flocs qui sous l'effet de l'attrition, se désagrègent en microflocs ou fines lors du passage de vannes, pompes, etc., et peuvent détruire l'équilibre du gâteau de filtration, passent dans le filtrat, etc. Le second problème est la présence de coagulant dans le filtrat, souvent suite à un excès de coagulant destiné à éviter le problème précédent. The solution containing the flocs thus obtained is then filtered, generally by filtration on a support. During this operation, there are many problems, including two main. The first is the lack of cohesion of the flocs which under the effect of attrition, disintegrate into microflocs or fines during the passage of valves, pumps, etc., and can destroy the balance of the filter cake, pass into the filtrate, etc. The second problem is the presence of coagulant in the filtrate, often following an excess of coagulant intended to avoid the previous problem.

"The behaviour of aggregates in stirred vessels",
Trans. I. Chem. E., vol. 56, pp 9-18, 1978 (Tomi et Bagoter) décrit la relation entre la dimension des flocs et le cycle agitation rapide à 500 tr/mn/agitation lente à 250 tr/mn, conduisant à une nette diminution de la dimension des flocs en fonction du temps d'agitation. "The role of rapid mixing time on a flocculation process", Wat. Sci. Tech., vol 17,
Amsterdam, pp 1091-1101 (François et Van Haute) enseigne qu'une agitation rapide est nécessaire à l'instant initial lors de la coagulation pour obtenir des flocs ayant une cohésion élevée. Cette agitation rapide avec un cisaillement
-l d'environ 330 s l doit néanmoins être effectuée pendant une durée inférieure à 150 s afin de ne pas nuire à la croissance et à la stabilité des flocs, et doit satisfaire plusieurs critères secondaires.Une agitation rapide optimale pendant 30 s est décrite comme étant optimale."The behavior of aggregates in stirred vessels",
Trans. I. Chem. E., vol. 56, pp 9-18, 1978 (Tomi and Bagoter) describes the relationship between the size of the flocs and the rapid agitation cycle at 500 rpm / slow agitation at 250 rpm, leading to a marked reduction in the dimension of the flocs depending on the stirring time. "The role of rapid mixing time on a flocculation process", Wat. Sci. Tech., Vol 17,
Amsterdam, pp 1091-1101 (François and Van Haute) teaches that rapid agitation is necessary at the initial moment during coagulation to obtain flocs with high cohesion. This rapid agitation with shear
-l approximately 330 sl must nevertheless be carried out for a duration of less than 150 s in order not to harm the growth and the stability of the flocs, and must satisfy several secondary criteria. Optimal rapid agitation for 30 s is described as being optimal.

Aucun des documents ci-dessus n'enseigne ni ne décrit la présente invention, ni n'apporte de solution réelle aux problèmes mentionnés ci-avant. None of the above documents teaches or describes the present invention, nor does it provide a real solution to the problems mentioned above.

De façon surprenante et inattendue, la présente invention permet de pallier les inconvénients de l'art antérieur. Surprisingly and unexpectedly, the present invention overcomes the drawbacks of the prior art.

Ainsi, la présente invention a pour objet un procédé de coagulation-floculation d'une suspension agrégative et contenant un coagulant, comprenant au moins, à l'instant initial, un cycle opératoire initial consistant en les deux étapes suivantes:
(i) une étape d'agitation rapide avec un gradient de vélo
cité moyenne compris entre 300 et 1 000 s 1 pendant
une durée comprise entre 30 et 200 s; et
(ii) une étape d'agitation lente avec un gradient de vélo
cite
cité moyenne compris entre 40 et 100 s , pendant une
durée comprise entre 5 et 40 mn.Thus, the subject of the present invention is a method of coagulation-flocculation of an aggregative suspension and containing a coagulant, comprising at least, at the initial instant, an initial operating cycle consisting of the following two steps:
(i) a rapid agitation stage with a bicycle gradient
average city between 300 and 1000 s 1 during
a duration between 30 and 200 s; and
(ii) a slow agitation step with a cycling gradient
quote
average city between 40 and 100 s, during a
duration between 5 and 40 min.

Le gradient de vélocité moyenne de l'étape d'agitation rapide est compris de préférence d'environ 450 s s tandis que le gradient de vélocité moyenne de l'étape d'agitation lente est de préférence d'environ 85
La durée de l'étape d'agitation rapide est de préférence comprise entre 120 et 200 s, et est avantageusement d'environ 180 s. La durée de l'étape d'agitation rapide est de préférence d'environ 30 mn.The average velocity gradient of the fast stirring step is preferably around 450 ss while the average velocity gradient of the slow stirring step is preferably around 85
The duration of the rapid stirring step is preferably between 120 and 200 s, and is advantageously around 180 s. The duration of the rapid stirring step is preferably about 30 min.

Tout coagulant habituellement employé peut être utilisé. Cependant, de préférence, le coagulant est choisi dans le groupe consistant en Fez13, polychlorure d'aluminium (PAC),
Al2(S04)3, et leurs mélanges.Any commonly used coagulant can be used. However, preferably, the coagulant is chosen from the group consisting of Fez13, poly aluminum chloride (PAC),
Al2 (S04) 3, and mixtures thereof.

Le pH de la suspension est compris entre 5 et 9, de préférence entre 5,5 et 8.5. The pH of the suspension is between 5 and 9, preferably between 5.5 and 8.5.

Selon un mode de réalisation de la présente invention, le procédé outre le cycle opératoire initial précité comprend en outre au moins un cycle, de préférence deux cycles opératoires supplémentaires. Le ou lesdits cycle(s) opératoire(s) supplémentaire(s) consiste(nt) également en deux étapes d'agitation rapide et lente. De préférence, le gradient de vélocité moyenne de l'étape d'agitation rapide est augmenté d'un cycle au cycle suivant. Avantageusement, le gradient de vélocité moyenne de l'étape d'agitation rapide est augmenté d'au moins -1 environ 225 s 1 d'un cycle au cycle suivant. Le gradient de vélocité moyenne de l'étape d'agitation lente reste substantiellement constant au cours des différents cycles. According to an embodiment of the present invention, the method in addition to the abovementioned initial operating cycle further comprises at least one cycle, preferably two additional operating cycles. The said additional operating cycle (s) also consists of two stages of rapid and slow agitation. Preferably, the average velocity gradient of the rapid stirring step is increased from one cycle to the next cycle. Advantageously, the average velocity gradient of the rapid stirring step is increased by at least -1 approximately 225 s 1 from one cycle to the next cycle. The average velocity gradient of the slow stirring step remains substantially constant during the different cycles.

Selon un mode d'exécution préféré de la présente invention, la durée de l'étape d'agitation rapide reste substantiellement constante d'un cycle au cycle suivant. Similairement, la durée de l'étape d'agitation lente reste substantiellement constante d'un cycle au cycle suivant. According to a preferred embodiment of the present invention, the duration of the rapid stirring step remains substantially constant from one cycle to the next cycle. Similarly, the duration of the slow stirring step remains substantially constant from one cycle to the next.

Le procédé particulièrement préféré selon la présente invention consiste en les 3 cycles (a),(b) et (c) suivants:
(a)(i) une étape d'agitation rapide avec un gradient de -1
vélocité moyenne d'environ 450 s 1 pendant une
durée d'environ 180 s; et
(ii) une étape d'agitation lente avec un gradient de vélocité moyenne d'environ 85 s 1 pendant une
durée d'environ 30 mn;
(b)(i) une étape d'agitation rapide avec un gradient de -l
vélocité moyenne d'environ 725 s pendant une
durée d'environ 180 s; et
(ii) une étape d'agitation lente avec un gradient de -1
vélocité moyenne d'environ 85 s 1 pendant une
durée d'environ 30 mn;
(c)(i) une étape d'agitation rapide avec un gradient de -l
vélocité moyenne d'environ 1000 s 1 pendant une
durée d'environ 180 s;et
(ii) une étape d'agitation lente avec un gradient de -l
vélocité moyenne d'environ 85 s 1 pendant une
durée d'environ 30 mn.The particularly preferred process according to the present invention consists of the following 3 cycles (a), (b) and (c):
(a) (i) a rapid agitation step with a gradient of -1
average velocity of approximately 450 s 1 during one
duration of about 180 s; and
(ii) a slow stirring step with an average velocity gradient of approximately 85 s 1 during one
duration of approximately 30 min;
(b) (i) a rapid stirring step with a gradient of -l
average velocity of approximately 725 s during
duration of about 180 s; and
(ii) a slow stirring step with a gradient of -1
average velocity of approximately 85 s 1 during a
duration of approximately 30 min;
(c) (i) a rapid stirring step with a gradient of -l
average velocity of approximately 1000 s 1 during a
duration of approximately 180 s; and
(ii) a slow stirring step with a gradient of -l
average velocity of approximately 85 s 1 during a
duration of approximately 30 min.

Tout appareil, classiquement utilisé en coagulationfloculation, peut être utilisé dans la présente invention. De tels appareils sont les agitateurs à hélices, à pales, à ruban, à ancre, à rotor/stator, à impeller, avec ou sans chicane, statique, etc. Any device, conventionally used in coagulation-flocculation, can be used in the present invention. Such devices are propeller, paddle, ribbon, anchor, rotor / stator, impeller, with or without baffle, static, etc. agitators.

La figure 1 représente un agitateur pour la mise en oeuvre du procédé selon la présente invention. FIG. 1 represents an agitator for implementing the method according to the present invention.

Les figures 2a à Sa représentent les courbes de la dimension moyenne des flocs en fonction de la durée d'agitation pour deux procédés, l'un selon l'art antérieur (figures 2a à 5a), l'autre selon la présente invention (figures 2b à 5b), pour diverses suspensions agrégatives. FIGS. 2a to Sa represent the curves of the average dimension of the flocs as a function of the duration of agitation for two methods, one according to the prior art (FIGS. 2a to 5a), the other according to the present invention (FIGS. 2b to 5b), for various aggregation suspensions.

La présente invention est maintenant décrite plus en détail par la description suivante et des exemples de mise en oeuvre donnés à titre illustratif et nullement limitatif. The present invention is now described in more detail by the following description and examples of implementation given by way of illustration and in no way limitative.

EXEMPLES
L'appareil d'agitation est schématisé figure 1. Il s'agit d'un agitateur à pale et chicane, dont les caractéristiques, en référence à la figure 1, sont les suivantes:
L'agitateur 1 est un bécher cylindrique de diamètre intérieur 95 mm et de hauteur 165 mm. La hauteur de liquide dans l'agitateur est de 150 mm. L'agitateur 1 possède une pale d'agitation 2. Cette pale d'agitation a un diamètre de 60 mm, une hauteur de 15 mm, et elle est montée sur un axe dont le diamètre est de 5 mm. L'axe de la pale se confond avec l'axe de l'agitateur cylindrique. La pale d'agitation est agencée au centre de l'agitateur et selon une hauteur de sorte que l'extrémité inférieure de la pale se trouve à 50 mm du fond de l'agitateur 1. L'agitateur 1 est par ailleurs muni de quatre chicanes 3 disposées régulièrement à l'intérieur de celui-ci; la largeur des chicanes 3 est de 12,5 mm.La prélèvement du liquide surnageant se fait par l'intermédiaire d'un tube plongeant 4 situé à 15 mm en-dessous du niveau supérieur de l'agitateur 1. La géométrie de cet agitateur permet de déterminer le gradient de vélocité moyen en fonction du nombre de tr/mn de la pale d'agitation.EXAMPLES
The stirring apparatus is shown diagrammatically in FIG. 1. It is a paddle and baffle agitator, the characteristics of which, with reference to FIG. 1, are as follows:
The agitator 1 is a cylindrical beaker with an internal diameter of 95 mm and a height of 165 mm. The height of the liquid in the agitator is 150 mm. The agitator 1 has a stirring blade 2. This stirring blade has a diameter of 60 mm, a height of 15 mm, and it is mounted on an axis whose diameter is 5 mm. The axis of the blade merges with the axis of the cylindrical agitator. The stirring blade is arranged in the center of the agitator and at a height so that the lower end of the blade is 50 mm from the bottom of the agitator 1. The agitator 1 is moreover provided with four baffles 3 regularly arranged inside thereof; the width of the baffles 3 is 12.5 mm. The withdrawal of the supernatant liquid is done via a dip tube 4 located 15 mm below the upper level of the agitator 1. The geometry of this agitator used to determine the average velocity gradient as a function of the number of rpm of the stirring blade.

La suspension agrégative utilisée est une suspension de synthèse. Cette suspension est une suspension aqueuse à la température de -20 C, et préparée à partir de silice à 500 ppm (silice Ludox HS 40) et d'électrolyte NaHCO3/NaCl selon une concentration de 336 ppm/70 ppm. The aggregation suspension used is a synthesis suspension. This suspension is an aqueous suspension at the temperature of -20 C, and prepared from silica at 500 ppm (Ludox HS 40 silica) and electrolyte NaHCO3 / NaCl at a concentration of 336 ppm / 70 ppm.

La coagulation-floculation est effectuée pour une dose en coagulant définie par un jartest classique, c'est-à-dire la meilleure clarification obtenue pour la dose en coagulant la plus faible possible. Coagulation-flocculation is carried out for a coagulating dose defined by a conventional jartest, that is to say the best clarification obtained for the lowest possible coagulating dose.

Deux protocoles d'agitation ont été mis en oeuvre, pour chacun d'entre eux, le cycle complet est appliqué sur la même suspension. Le protocole I correspond au témoin comparatif tandis que le protocole Il est un protocole selon la présente invention. Ces deux protocoles sont définis dans le tableau I ci-après. L'ajout de coagulant est effectué à t = 0. Two agitation protocols have been implemented, for each of them, the complete cycle is applied to the same suspension. Protocol I corresponds to the comparative control while protocol II is a protocol according to the present invention. These two protocols are defined in Table I below. The addition of coagulant is carried out at t = 0.

TABLEAU I
PROTOCOLE I PROTOCOLE Il
Intensité de Gradient de Temps Intensité de Gradient de Temps t'agitation vélocité d'agitation L'agitation vélocité d'agitation
(tr/mn) moyenne (s ) (mn) (tr/mn) moyenne (s ) (mn)
60 85 3 250 450 3
60 85 30 60 85 30
120 190 3 350 725 3
60 85 30 60 85 30
250 450 3 450 1000 3
60 85 30 60 85 30
Pendant les différentes étapes d'agitation, la dimension moyenne des flocs et le volume total des flocs exprimés en % du volume irradié par le faisceau de mesure ont été analysés et enregistrés. Les mesures sont effectuées par diffraction de la lumière au moyen d'un appareil Malvern
Master Sizer, dont la gamme de mesure de dimensions est de 0,1 à 600 pm.TABLE I
PROTOCOL I PROTOCOL It
Time Gradient Intensity Time Gradient Intensity agitation agitation velocity Agitation agitation velocity
(rpm) average (s) (min) (rpm) average (s) (min)
60 85 3 250 450 3
60 85 30 60 85 30
120 190 3 350 725 3
60 85 30 60 85 30
250 450 3 450 1000 3
60 85 30 60 85 30
During the various agitation steps, the average size of the flocs and the total volume of the flocs expressed as a% of the volume irradiated by the measurement beam were analyzed and recorded. Measurements are made by light diffraction using a Malvern device
Master Sizer, whose dimension measurement range is 0.1 to 600 µm.

Le tableau Il donne les valeurs obtenues, ces valeurs étant reportées aux figures 2a à Sa (protocole I) et aux figures 2b et 5b (protocole Il, invention). Dans ce tableau Il, t signifie le temps d'agitation en seconde, P50 est le diamètre moyen des flocs en pm, et Vc est le volume total des flocs exprimés en % du volume irradié par le faisceau de mesure. Table II gives the values obtained, these values being reported in FIGS. 2a to Sa (protocol I) and in FIGS. 2b and 5b (protocol II, invention). In this table II, t signifies the stirring time in seconds, P50 is the average diameter of the flocs in pm, and Vc is the total volume of the flocs expressed in% of the volume irradiated by the measurement beam.

EXEMPLE 1
Le coagulant est Fez13, à une concentration de
-4 -1 1,28.10 mol.l . Le pH de la suspension est de 5,5. EXAMPLE 1
The coagulant is Fez13, at a concentration of
-4 -1 1.28.10 mol.l. The pH of the suspension is 5.5.

Les résultats des mesures sont reportés dans le tableau ci-après donnant le diamètre moyen et le volume total des flocs en fonction de la durée d'agitation. Les graphiques correspondants sont reportés à la figure 2. Les deux protocoles sont mis en oeuvre, les figures 2a et 2b correspondant respectivement aux protocoles I et Il.  The results of the measurements are reported in the table below giving the average diameter and the total volume of the flocs as a function of the duration of agitation. The corresponding graphics are shown in FIG. 2. The two protocols are implemented, FIGS. 2a and 2b corresponding respectively to protocols I and II.

Deux comportements peuvent clairement être distingués en fonction du protocole choisi. Le protocole I, correspondant à une agitation 60/60 - 120/60 - 250/60 conduit à une dégradation lente et régulière de la taille du floc pendant la première phase 60/60; cette dégradation se poursuit lors des phases de rupture à 120 et 250 tr/mn par une chute brutale et irréversible, d'une part, du diamètre moyen des particules dont la valeur se stabilise à une valeur d'environ 10 pm lors du retour à l'agitation lente à 60 tr/mn et, d'autre part, du volume total des flocs.Le début du protocole Il d'agitation 250/60 - 350/60 - 450/60 présente également à la suite de la formation des flocs, une baisse rapide de la dimension moyenne des flocs jusqu a une valeur d'environ 150 pm. Mais à la différence du protocole I précédent, les ruptures produites par les étapes d'agitation à 350 et 450 tr/mn sont réversibles et le passage à l'étape d'agitation lente se traduit par le retour à cette dimension d'équilibre de 150 pm. La courbe donnant la concentration en volume des flocs en fonction du temps d'agitation retranscrit le même phénomène; les différentes ruptures ne modifient pas le volume total des flocs. Two behaviors can clearly be distinguished depending on the protocol chosen. Protocol I, corresponding to 60/60 - 120/60 - 250/60 agitation, leads to a slow and regular degradation of the size of the floc during the first 60/60 phase; this deterioration continues during the rupture phases at 120 and 250 rpm by a sudden and irreversible fall, on the one hand, in the average diameter of the particles whose value stabilizes at a value of approximately 10 μm when returning to slow agitation at 60 rpm and, on the other hand, the total volume of the flakes. The start of the agitation protocol Il 250/60 - 350/60 - 450/60 also occurs following the formation of flocs, a rapid drop in the average dimension of the flocs to a value of about 150 µm. But unlike the previous protocol I, the ruptures produced by the stirring steps at 350 and 450 rpm are reversible and the transition to the slow stirring step results in the return to this dimension of equilibrium of 150 pm. The curve giving the volume concentration of the flocs as a function of the agitation time transcribes the same phenomenon; the different ruptures do not modify the total volume of the flocs.

Ainsi, le chlorure ferrique FeCl3 à pH 5,5 conduit à des flocs d'une part plus résistants et d'une dimension augmentée lorsque l'étape d'agitation rapide initiale est effectuée avec une agitation de 250 tr/mn. Les ruptures ultérieures subies par les flocs n'altèrent peu ou pas leur dimension moyenne et n'entraînent pas la production de fines. Thus, the ferric chloride FeCl3 at pH 5.5 leads to flocs on the one hand more resistant and of an increased dimension when the initial rapid stirring step is carried out with stirring of 250 rpm. The subsequent ruptures suffered by the flocs do not alter their average size little or not and do not lead to the production of fines.

Les résultats obtenus avec la concentration volumique des flocs Vc, en fonction du temps d'agitation, donnés tableau Il, montrent le même phénomène; les phases de rupture ne modifient pas le volume du floc. The results obtained with the volume concentration of the flocs Vc, as a function of the agitation time, given in Table II, show the same phenomenon; the failure phases do not modify the volume of the flock.

EXEMPLE 2
Le coagulant est FeCl3, à une concentration de
-4 -1 8,45.10 4 mol.l . Le pH de la suspension est de 7,0. EXAMPLE 2
The coagulant is FeCl3, at a concentration of
-4 -1 8.45.10 4 mol.l. The pH of the suspension is 7.0.

Les résultats des mesures sont reportés dans le tableau ci-après donnant le diamètre moyen et le volume total des flocs en fonction de la durée d'agitation. Le graphique donnant le dimètre moyen est en figure 3. Les deux protocoles sont mis en oeuvre, les figures 3a et 3b correspondant respectivement aux protocoles I et Il.  The results of the measurements are reported in the table below giving the average diameter and the total volume of the flocs as a function of the duration of agitation. The graph giving the average dimeter is in FIG. 3. The two protocols are implemented, FIGS. 3a and 3b corresponding respectively to protocols I and II.

Le comportement du chlorure ferrique vis-à-vis de l'agitation à pH 7,0 est globalement similaire à celui à pH 5,5. The behavior of ferric chloride vis-à-vis stirring at pH 7.0 is generally similar to that at pH 5.5.

Une augmentation de l'intensité de mélange en cours d'agitation conduit à une dégradation irréversible du floc lorsque le protocole I est utilisé; au contraire, la dimension moyenne du floc se trouve restaurée après les ruptures (début d'étape d'agitation rapide) lorsque le protocole Il est utilisé.An increase in the intensity of mixing during agitation leads to irreversible degradation of the floc when protocol I is used; on the contrary, the average size of the floc is restored after the ruptures (start of rapid agitation step) when the protocol It is used.

EXEMPLE 3
Le coagulant est le WAC HB à une concentration de 4,41.10 4 mol.l1. Le pH de la suspension est de 8,0. EXAMPLE 3
The coagulant is WAC HB at a concentration of 4.41.10 4 mol.l1. The pH of the suspension is 8.0.

Les résultats des mesures sont reportés sous forme de graphiques donnant le diamètre moyen et le volume total des flocs en fonction de la durée d'agitation. Le graphique donnant le diamètre moyen est en figure 4. Les deux protocoles sont mis en oeuvre, les figures 4a et 4b correspondant respectivement aux protocoles I et Il.  The results of the measurements are reported in the form of graphs giving the average diameter and the total volume of the flocs as a function of the duration of agitation. The graph giving the average diameter is in FIG. 4. The two protocols are implemented, FIGS. 4a and 4b corresponding respectively to protocols I and II.

Les données utilisées pour obtenir ces courbes, qui se trouvent au tableau Il, expriment aussi la concentration volumique des flocs Vc en fonction du temps. The data used to obtain these curves, which are found in Table II, also express the volume concentration of the flocs Vc as a function of time.

Le WAC HB est un polychlorure d'aluminium correspondant à la formule du chlorosulfate d'aluminium basique: AlnOHm(So4)kCl3n-m-2k formule dans laquelle la basicité ou le rapport molaire (m/3n)xlOO est compris entre 40% environ et 65% environ, et qui présente un rapport équivalent Al/équivalent Cl compris entre 2,8 et 5, une masse moléculaire apparente MA, mesurée par diffusion de lumière classique, et des diamètres hydrodynamiques apparents Z et W, mesurés par diffusion quasiélastique de la lumière, présentant les valeurs respectives suivantes:
MA = 7000-35000
z(A) = 350-2500
w(Â) = 200-1200.WAC HB is a poly aluminum chloride corresponding to the formula of basic aluminum chlorosulfate: AlnOHm (So4) kCl3n-m-2k formula in which the basicity or the molar ratio (m / 3n) xlOO is between approximately 40% and approximately 65%, and which has an Al equivalent / Cl equivalent ratio of between 2.8 and 5, an apparent molecular mass MA, measured by conventional light scattering, and apparent hydrodynamic diameters Z and W, measured by quasielastic scattering of light, with the following respective values:
MA = 7000-35000
z (A) = 350-2500
w (Â) = 200-1200.

Ce produit est décrit dans FR-A-2 584 699.This product is described in FR-A-2 584 699.

Le comportement du WAC HB est similaire au comportement de Fez13. En effet, la dimension moyenne du floc passe de 300 à 150 pm dans le cas du protocole I, et de 300 à 270 pm dans le cas du protocole Il; la courbe de la dimension moyenne témoigne des ruptures irréversibles obtenues avec le protocole I, et réversibles avec le protocole Il.  The behavior of WAC HB is similar to the behavior of Fez13. In fact, the average size of the floc increases from 300 to 150 μm in the case of protocol I, and from 300 to 270 μm in the case of protocol II; the curve of the average dimension shows the irreversible ruptures obtained with protocol I, and reversible with protocol II.

EXEMPLE 4
Le coagulant est le sulfate d'aluminium Al2(S04)3 à une concentration de 8,24.10 4 mol.l1; le pH de la suspension est de 8,0.EXAMPLE 4
The coagulant is aluminum sulphate Al2 (SO4) 3 at a concentration of 8.24.10 4 mol.l1; the pH of the suspension is 8.0.

Les résultats des mesures sont reportés dans le tableau
Il ci-après donnant le diamètre moyen et le volume total des flocs en fonction de la durée d'agitation. Le graphique donnant le diamètre moyen est en figure 5. Les deux protocoles sont mis en oeuvre, les figures Sa et 5b correspondant respectivement aux protocoles I et Il. The results of the measurements are shown in the table
It hereafter giving the average diameter and the total volume of the flocs as a function of the duration of agitation. The graph giving the mean diameter is in FIG. 5. The two protocols are implemented, FIGS. Sa and 5b corresponding respectively to protocols I and II.

Le comportement du Al2(S04)3 est similaire à celui des coagulants précédents. En effet, la dimension moyenne du floc passe de 310 à 295 pm dans le cas du protocole I, alors que la dimension moyenne du floc reste supérieure à 305 pm dans le cas du protocole Il. De même, les courbes données à la figure 5 montrent le caractère irréversible des ruptures selon le protocole I, et le caractère réversible des ruptures selon le protocole Il.  The behavior of Al2 (SO4) 3 is similar to that of the previous coagulants. In fact, the average dimension of the floc increases from 310 to 295 μm in the case of protocol I, while the average dimension of the floc remains greater than 305 μm in the case of protocol II. Similarly, the curves given in FIG. 5 show the irreversible nature of the ruptures according to protocol I, and the reversible nature of the ruptures according to protocol II.

Ainsi, la présente invention fournit un procédé de coagulation-floculation comprenant une agitation rapide lors de la phase initiale de coagulation conduisant à des flocs d'une dimension et d'une résistance mécanique supérieure. Il ne se produit pas de formation irréversible de microflocs après passage des flocs dans les pompes, restrictions de tubes, et lors de la formation du gâteau de filtration. TABLEAU II
FIG 2a FIG 2b
t P50 Vc t P50 Vc
0,000 0,000
17,000 17,150 0,002 7,000
36,000 49,120 0,030 33,000 93,960 0,020
53,000 67,160 0,068 48,000 290,730 0,777
72,000 74,570 0,087 70,000 278,710 0,730
91,000 75,690 0,101 92,000 251,270 0,663
108,000 76,620 0,108 114,000 248,860 0,657
125,000 75,900 0,111 135,000 226,090 0,598
142,000 75,470 0,110 157,000 221,660 0,582
161,000 74,300 0,112 178,000 206,020 0,547
180,000 72,810 0,112 200,000 228,650 0,641
197,000 71,670 0,112 221,000 230,540 0,644
216,000 70,970 0,115 251,000 226,480 0,641
241,000 69,590 0,119 378,000 194,860 0,603
366,000 63,620 0,111 505,000 182,600 0,564
490,000 59,200 0,104 632,000 176,080 0,567
612,000 56,110 0,101 759,000 169,750 0,534
736,000 54,100 0,103 886,000 166,480 0,530
859,000 52,510 0,097 1012,000 160,740 0,529
902,000 50,870 0,094 1139,000 159,020 0,512 1107,000 49,830 0,098 1266,000 156,730 0,510 1229,000 48,760 0,092 1393,000 155,060 0,509 1353,000 47,920 0,091 1520,000 151,720 0,496 1477,000 47,030 0,089 1646,000 150,250 0,498 1602,000 46,200 0,087 1774,000 147,420 0,486 1728,000 45,570 0,088 1962,000 147,350 0,483 1979,000 44,490 0,087 1984,000 144,880 0,464 1997,000 43,290 0,085 2006,000 153,160 0,389 2016,000 40,540 0,067 2022,000 152,790 0,376 2034,000 37,820 0,058 2038,000 151,270 0,369 2053,000 35,090 0,049 2055,000 148,480 0,362 2073,000 32,520 0,042 2071,000 147,240 0,358 2090,000 30,560 0,037 2087,000 146,430 0,358 2108,000 28,920 0,034 2103,000 143,670 0,348 2125,000 27,480 0,032 2119,000 143,010 0,342 2144,000 26,190 0,029 2136,000 141,960 0,339 2164,000 25,120 0,028 2162,000 140,910 0,335 2181,000 25,390 0,028 2183,000 152,780 0,440 2200,000 26,150 0,029 2310,000 156,630 0,504 2221,000 26,570 0,029 2437,000 153,840 0,499 FIG 2a (suite) FIG 2b
t P50 Vc t P50 Cc 2345,000 27,700 0,031 2564,000 151,120 0,507 2469,000 28,070 0,032 2690,000 148,120 0,492 2592,000 28,190 0,035 2816,000 146,440 0,489 2716,000 28,120 0,033 2944,000 145,430 0,492 2838,000 28,070 0,035 4069,000 142,160 0,492 2963,000 27,990 0,033 3196,000 142,070 0,484 3087,000 27,830 0,033 3323,000 140,500 0,476 3209,000 27,760 0,035 3450,000 140,060 0,483 3333,000 27,650 0,033 3576,000 138,600 0,484 3455,000 27,470 0,033 3703,000 138,480 0,477 3680,000 27,450 0,036 3954,000 136,520 0,476 3704,000 27,240 0,033 3976,000 131,520 0,363 3960,000 26,900 0,035 3992,000 132,440 0,290 3981,000 23,360 0,026 4008,000 131,280 0,278 4000,000 16,560 0,011 4024,000 128,530 0,268 4017,000 11,410 0,007 4041,000 125,900 0,257 4036,000 8,880 0,005 4057,000 125,970 0,258 4055,000 7,620 0,004 4074,000 123,270 0,249 4072,000 6,990 0,004 4090,000 120,660 0,244 4091,000 6,510 0,003 4106,000 120,330 0.242 4108,000 6,330 0,003 4123,000 118,780 0,240 4127,000 6,040 0,003 4139,000 117,030 0,236 4148,000 5,850 0,003 4160,000 136,210 0,385 4165,000 5,860 0,003 4282,000 146,290 0,488 4184,000 5,880 0,003 4409,000 141,190 0,478 4207,000 5,910 0,004 4536,000 138,780 0,476 4331,000 6,060 0,004 4663,000 139,040 0,480 4455,000 6,250 0,004 4790,000 135,570 0,480 4577,000 6,350 0,004 4916,000 135,500 0,480 4701,000 6,480 0,004 5043,000 134,280 0,474 4823,000 6,670 0,004 5170,000 133,330 0,471 4947,000 6,780 0,004 5297,000 132,320 0,472 5071,000 7,000 0,004 5424,000 131,930 0,473 5193,000 7,130 0,004 5551,000 131,190 0,474 5317,000 7,070 0,004 5678,000 130,270 0,474 5440,000 7,060 0,005 5564,000 7,480 0,004 5688,000 7,140 0,004 FIG 3a (suite) FIG 3b
t P50 Vc t P50 Vc
0,000 0,000
19,000 303,710 0,783 19,000 301,590 1,313
37,000 305,130 1,612 42,000 294,650 1,349
59,000 299,330 1,489 63,000 293,800 1,302
82,000 296,390 1,873 86,000 293,630 1,305
106,000 297,310 1,914 110,000 293,740 1,300
127,000 297,100 1,950 131,000 295,090 1,275
150,000 296,900 1,979 154,000 294,790 1,264
172,000 296,530 2,021 175,000 294,670 1,249
195,000 296,590 2,005 199,000 295,680 1,304
218,000 296,620 2,035 222,000 295,530 1,302
240,000 296,410 2,021 243,000 295,200 1,308
263,000 297,060 1,993 266,000 295,170 1,302
303,000 296,150 2,059 294,000 294,840 1,301
431,000 295,610 2,053 422,000 294,850 1,309
560,000 295,200 2,064 551,000 294,240 1,273
686,000 295,290 2,032 677,000 293,960 1,265
815,000 295,220 806,000 294,080 1,280
941,000 294,480 2,031 932,000 293,310 1,260 1070,000 294,610 2,062 1060,000 293,080 1,258 1198,000 294,310 2,030 1189,000 293,440 1,270 1325,000 294,090 2,033 1315,000 292,780 1,250 1453,000 294,420 2,024 1443,000 292,930 1,259 1580,000 294,180 1,985 1570,000 292,700 1,240 1708,000 294,260 1,994 1698,000 292,280 1,240 1837,000 294,340 2,010 1826,000 1979,000 294,110 2,000 1992,000 292,100 1,179 2002,000 293,390 1,979 2015,000 294,410 1,154 2026,000 292,990 1,880 2039,000 294,980 1,147 2047,000 292,610 1,847 2060,000 295,000 1,146 2070,000 292,450 1,819 2083,000 295,320 1,147 2094,000 292,020 1,799 2106,000 295,280 1,135 2115,000 291,910 1,789 2128,000 295,280 1,128 2139,000 291,660 1,768 2151,000 294,870 1,124 2160,000 291,580 1,760 2172,000 297,460 1,180 2184,000 291,530 1,748 2195,000 297,960 1,222 2207,000 291,360 1,760 2219,000 297,360 1,227 2229,000 291,390 1,776 2240,000 296,900 1,231 2250,000 291,480 1,771 2263,000 296,760 1,226 2286,000 291,150 1,765 2288,000 296,520 1,222 FIG 3a (suite) FIG 3b
t P50 Vc t P50 Vc 2415,000 290,890 1,783 2417,000 295,790 1,224 2543,000 290,930 1,773 2545,000 295,390 1,238 2670,000 290,780 1,754 2672,000 295,340 1,254 2799,000 292,150 1,749 2800,000 294,760 1,240 2925,000 292,220 1,760 2926,000 294,390 1,241 3053,000 292,060 1,759 3055,000 293,880 1,233 3182,000 291,030 1,753 3183,000 293,450 1,245 3308,000 291,930 1,756 3309,000 293,120 1,254 3436,000 291,790 1,767 3437,000 292,300 1,233 3563,000 291,610 1,767 3564,000 292,040 1,229 3692,000 291,790 1,766 3692,000 291,390 1,231 3821,000 291,650 1,745 3820,000 290,110 1,228 3975,000 291,510 1,755 3966,000 288,170 1,224 3998,000 289,230 1,757 3990,000 291,300 1,104 4018,000 289,020 1,559 4013,000 288,710 1,080 4039,000 288,810 1,429 4034,000 291,910 1,076 4063,000 288,810 1,386 4057,000 289,920 1,056 4087,000 288,760 1,360 4081,000 288,540 1,035 4108,000 288,810 1,333 4102,000 288,190 1,032 4131,000 288,370 1,329 4125,000 287,580 1,021 4153,000 288,690 1,320 4147,000 287,470 1,024 4176,000 288,670 1,305 4170,000 300,200 1,211 4202,000 289,590 1,308 4193,000 299,370 1,222 4224,000 289,440 1,384 4215,000 298,790 1,227 4247,000 289,380 1,393 4238,000 298,320 1,228 4285,000 289,120 1,390 4282,000 297,750 1,231 4414,000 288,750 1,396 4411,000 297,520 1,230 4542,000 288,660 1,389 4539,000 296,550 1,231 4669,000 288,770 1,387 4666,000 296,320 1,252 4797,000 288,490 1,383 4794,000 295,600 1,249 4924,000 288,310 1,376 4920,000 294,250 1,234 5053,000 288,160 1,380 5049,000 293,880 1,224 5181,000 288,080 1,375 5177,000 294,052 1,237 5308,000 287,430 1,377 5304,000 293,250 1,235 5436,000 287,330 1,370 5432,000 292,820 1,231 5563,000 286,700 1,368 5558,000 290,560 1,221 5691,000 286,830 1,369 5687,000 289,370 1,234 5810,000 286,340 1,384 5815,000 288,460 1,231 FIG 4a (suite) FIG 4b
t P50 Vc t P50 Vc
0,000 0,000
11,000 17,000 310,990 0,858
21,000 169,560 0,041 40,000 292,950 0,948
32,000 342,780 0,614 62,000 291,900 0,901
47,000 300,160 0,785 84,000 291,670 0,880
63,000 295,820 0,821 106,000 291,600 0,864
78,000 295,070 0,809 128,000 293,000 0,851
93,000 296,880 0,047 150,000 292,480 0,840
108,000 297,050 0,853 172,000 292,370 0,843
123,000 301,880 0,911 195,000 297,570 0,904
139,000 301,790 0,919 217,000 298,300 0,904
154,000 302,590 0,895 239,000 298,270 0,906
169,000 303,000 0,911 261,000 298,490 0,908
184,000 306,350 0,915 294,000 298,480 0,909
304,000 301,080 0,913 422,000 299,510 0,905
425,000 310,320 0,898 550,000 298,470 0,895
545,000 310,440 0,900 677,000 298,630 0,885
666,000 309,970 0,879 805,000 298,040 0,888
786,000 309,980 0,867 932,000 295,480 0,866
906,000 309,890 0,891 1059,000 292,040 0,857 1027,000 309,430 0,885 1187,000 288,510 0,847 1147,000 308,520 0,891 1314,000 286,770 0,847 1267,000 308,460 0,864 1442,000 283,510 0,835 1387,000 307,190 0,857 1568,000 271,710 0,802 1508,000 307,010 0,853 1695,000 265,130 0,790 1609,000 307,110 0,844 1822,000 266,480 0,798 1965,000 286,740 0,773 1963,000 260,330 0,776 1981,000 280,620 0,745 1986,000 211,250 0,675 1996,000 263,650 0,701 2008,000 218,940 0,667 2011,000 253,760 0,677 2030,000 223,030 0,665 2027,000 238,670 0,663 2052,000 227,760 0,667 2042,000 240,140 0,664 2075,000 229,400 0,666 2057,000 212,920 0,632 2097,000 231,530 0,664 2072,000 216,030 0,639 2119,000 229,420 0,658 2087,000 216,210 0,631 2140,000 224,050 0,642 2103,000 191,890 0,608 2163,000 250,750 0,708 2119,000 201,110 0,621 2186,000 299,970 0,848 2134,000 191,880 0,605 2207,000 299,930 0,857 2149,000 212,610 0,628 2230,000 299,280 0,854 2168,000 238,520 0,660 2257,000 298,950 0,853 FIG 4a (suite) FIG 4b
t P50 Vc t P50 Vc 2288,000 226,090 0,651 2513,000 297,930 0,849 2409,000 231,740 0,660 2640,000 292,010 0,827 2529,000 233,250 0,652 2768,000 287,310 0,816 2650,000 216,270 0,650 2894,000 283,990 0,811 2770,000 206,720 0,641 3022,000 284,080 0,808 2890,000 196,930 0,637 3150,000 276,710 0,791 3011,000 192,480 0,634 3277,000 275,310 0,786 3131,000 180,300 0,628 3405,000 261,370 0,756 3251,000 183,470 0,637 3532,000 260,620 0,757 3371,000 175,990 0,632 3659,000 260,040 0,752 3492,000 168,920 0,625 3787,000 3613,000 160,600 0,613 3941,000 252,200 0,743 3987,000 164,140 0,615 3964,000 193,740 0,612 4003,000 137,270 0,480 3987,000 185,380 0,531 4018,000 132,040 0,411 4008,000 188,320 0,525 4033,000 129,500 0,377 4031,000 196,450 0,533 4044,000 130,400 0,370 4053,000 197,130 0,528 4055,000 130,160 0,360 4075,000 198,110 0,522 4066,000 129,020 0,353 4092,000 199,040 0,524 4077,000 128,770 0,347 4109,000 199,630 0,521 4087,000 128,310 0,341 4126,000 201,000 0,520 4098,000 126,570 0,332 4143,000 221,400 0,609 4109,000 126,980 0,330 4165,000 302,280 0,840 4120,000 127,950 0,331 4187,000 302,350 0,841 4131,000 127,790 0,330 4216,000 300,960 0,844 4172,000 126,230 0,316 4344,000 299,890 0,850 4288,000 180,190 0,529 4472,000 297,980 0,844 4409,000 177,980 0,530 4599,000 296,770 0,841 4529,000 173,050 0,520 4727,000 293,020 0,837 4649,000 166,880 0,502 4854,000 287,650 0,828 4769,000 168,230 0,504 4981,000 283,150 0,812 4890,000 162,960 0,494 5109,000 281,430 0,805 5010,000 162,160 0,490 5236,000 279,280 0,802 5130,000 160,540 0,482 5364,000 276,850 0,804 5251,000 159,030 0,485 5491,000 275,020 0,799 5371,000 153,790 0,467 5619,000 269,360 0,778 5492,000 152,920 0,470 5747,000 268,030 0,775 5612,000 151,660 0,469 FIG 5a (suite) FIG 5b
t P50 Vc t P50 Vc
0,000 0,000
18,000 302,370 0,336 11,000 121,000 0,011
35,000 299,790 1,009 23,000 293,950 0,786
56,000 305,760 0,154 37,000 294,510 0,810
77,000 309,170 0,182 53,000 294,110 0,792
99,000 310,180 0,195 69,000 293,850 0,808
120,000 309,590 0,197 83,000 294,000 0,821
141,000 310,180 0,186 99,000 292,050 0,804
162,000 309,320 0,187 114,000 292,140 0,804
184,000 309,520 0,165 129,000 292,180 0,798
205,000 309,960 0,091 145,000 291,610 0,764
227,000 309,660 0,122 160,000 291,790 0,777
248,000 308,870 0,106 176,000 291,720 0,781
291,000 308,970 0,072 209,000 300,230 0,844
418,000 308,800 0,072 330,000 300,860 0,849
544,000 308,710 0,047 451,000 300,740 0,842
670,000 308,310 0,049 671,000 300,800 0,830
797,000 308,300 0,035 691,000 300,600 0,829
923,000 308,200 0,036 812,000 300,910 0,829 1049,000 308,220 0,025 932,000 300,690 0,828 1176,000 307,950 0,028 1053,000 300,810 0,838 1303,000 307,770 0,022 1173,000 300,540 0,839 1429,000 307,880 0,008 1293,000 300,470 0,818 1555,000 308,370 0,019 1413,000 300.570 0,822 1681,000 308,650 0,004 1534,000 300,640 0,824 1808,000 308,430 0,002 1655,000 300,590 0,821 1981,000 308,310 0,002 1976,000 300,140 0,814 2003,000 308,390 0,973 1992,000 291,760 0,760 2025,000 308,220 0,957 2007,000 288,720 0,712 2046,000 307,590 0,943 2022,000 288,440 0,688 2067,000 308,060 0,941 2038,000 288,150 0,677 2089,000 307,730 0,930 2054,000 286,410 0,658 2110,000 307,430 0,927 2069,000 286,530 0,630 2132,000 307,030 0,920 2080,000 286,900 0,618 2153,000 306,850 0,915 2090,000 283,560 0,604 2175,000 306,940 0,932 2101,000 278,480 0,577 2196,000 307,220 0,945 2113,000 277,930 0,553 2219,000 307,520 0,928 2123,000 271,140 0,530 2241,000 307,510 0,941 2134,000 282,200 0,537 2267,000 307,440 0,941 2157,000 263,130 0,477 FIG 5a (suite) FIG 5b
t P50 Vc t P50 Vc 2393,000 307,610 0,927 2274,000 294,550 0,769 2520,000 307,650 0,927 2394,000 296,380 0,776 2646,000 307,510 0,935 2514,000 295,400 0,787 2773,000 307,640 0,927 2635,000 295,890 0,785 2899,000 307,730 0,924 2755,000 296,130 0,758 3026,000 307,660 0,922 2876,000 295,820 0,763 3153,000 307,520 0,922 2997,000 295,830 0,759 3279,000 307,550 0,910 3117,000 296,880 0,753 3405,000 307,720 0,909 3237,000 295,190 0,756 3531,000 307,660 0,910 3357,000 294,890 0,767 3658,000 307,640 0,907 3478,000 293,930 0,761 3785,000 307,580 0,930 3599,000 293,940 0,738 3953,000 307,630 0,927 3957,000 293,770 0,733 3974,000 305,500 0,892 3973,000 251,690 0,757 3996,000 293,730 0,824 3985,000 229,950 0,329 4017,000 291,070 0,791 3995,000 219,310 0,288 4039,000 291,460 0,766 4006,000 202,440 0,246 4061,000 292,200 0,734 4018,000 198,220 0,229 4081,000 293,570 0,715 4028,000 189,260 0,208 4103,000 293,340 0,689 4039,000 178,000 0,184 4124,000 294,680 0,668 4050,000 170,400 0,167 4145,000 295,440 0,680 4061,000 162,800 0,150 4167,000 291,910 0,775 4073,000 149,700 0,131 4188,000 292,030 0,792 4084,000 149,340 0,125 4210,000 292,020 0,795 4095,000 138,080 0,111 4236,000 293,990 0,797 4122,000 129,350 0,085 4363,000 294,570 0,791 4238,000 297,260 0,589 4489,000 294,830 0,785 4355,000 290,010 0,605 4615,000 296,690 0,783 4471,000 291,560 0,615 4742,000 297,200 0,775 4587,000 280,110 0,578 4868,000 297,000 0,770 4702,000 282,710 0,590 4995,000 297,400 0,768 4819,000 279,690 0,585 5122,000 297,370 0,766 4935,000 279,540 0,578 5248,000 296,940 0,755 5051,000 278,680 0,588 5374,000 297,480 0,760 5167,000 277,800 0,583 5500,000 298,370 0,746 5282,000 274,500 0,575 5627,000 298,160 0,750 5399,000 276,730 0,584 5753,000 298,690 0,752 5515,000 265,540 0,577 Thus, the present invention provides a method of coagulation-flocculation comprising rapid agitation during the initial phase of coagulation leading to flocs of a greater size and mechanical strength. Irreversible formation of microflocs does not occur after the flocs have passed through the pumps, tube restrictions, and during the formation of the filter cake. TABLE II
FIG 2a FIG 2b
t P50 Vc t P50 Vc
0,000 0,000
17,000 17,150 0.002 7,000
36,000 49,120 0.030 33,000 93,960 0.020
53,000 67,160 0.068 48,000 290,730 0.777
72,000 74,570 0.087 70,000 278,710 0.730
91,000 75,690 0.101 92,000 251,270 0.663
108,000 76,620 0.108 114,000 248,860 0.657
125,000 75,900 0.111 135,000 226,090 0.598
142,000 75,470 0.110 157,000 221,660 0.582
161,000 74,300 0.112 178,000 206,020 0.547
180,000 72,810 0.112 200,000 228,650 0.641
197,000 71,670 0.112 221,000 230,540 0.644
216,000 70,970 0.115 251,000 226,480 0.641
241,000 69,590 0.119 378,000 194,860 0.603
366,000 63,620 0.111 505,000 182,600 0.564
490,000 59,200 0.104 632,000 176.080 0.567
612,000 56,110 0.101 759,000 169,750 0.534
736,000 54,100 0.103 886,000 166,480 0.530
859,000 52,510 0.097 1,012,000 160,740 0.529
902,000 50,870 0.094 1,139,000 159,020 0.512 1,107,000 49,830 0.098 1,266,000 156,730 0.510 1,229,000 48,760 0.092 1,393,000 155.060 0.509 1,353,000 47.920 0.091 1,520,000 151,720 0.496 1,477,000 47.030 0.089 1,646,000 150,250 0.498 1,602, 000 46,200 0.087 1,774,000 147,420 0.486 1,728,000 45,570 0.088 1962,000 147,350 0.483 1979,000 44,490 0.087 1984,000 144,880 0.464 1997,000 43,290 0.085 2006,000 153,160 0.389 2016,000 40,540 0.067 2,022,000 152,790 0.376 2,034, 000 37.820 0.058 2038,000 151.270 0.369 2053,000 35.090 0.049 2055,000 148.480 0.362 2073,000 32.520 0.042 2071,000 147.240 0.358 2090,000 30.560 0.037 2087,000 146.430 0.358 2108,000 28.920 0.034 2103,000 143.670 0.348 2125, 000 27.480 0.032 2119,000 143.010 0.342 2144,000 26.190 0.029 2136,000 141.960 0.339 2164,000 25.120 0.028 2162,000 140.910 0.335 2181,000 25.390 0.028 2183,000 152.780 0.440 2200,000 26.150 0.029 2310,000 156.630 0.504 2221, 000 26.570 0.029 2437,000 153.840 0.499 FIG 2a (continued) FIG 2b
t P50 Vc t P50 Cc 2,345,000 27,700 0.031 2,564,000 151.120 0.507 2,469,000 28.070 0.032 2,690,000 148,120 0.492 2,592,000 28,190 0.035 2,816,000 146,440 0.489 2,716,000 28,120 0.033 2,944,000 145,430 0.492 2,838,000 28,070 0.0354069,000 142.160 0.492 2963,000 27.990 0.033 3,196,000 142.070 0.484 3,087,000 27.830 0.033 3,323,000 140,500 0.476 3,209,000 27,760 0.035 3,450,000 140.060 0.483 3,333,000 27,650 0.033 3,576,000 138,600 0.484 3,455,000 27,470 0.033 3703,000 138.480 0.477 3680,000 27.450 0.036 3954,000 136.520 0.476 3704,000 27.240 0.033 3976,000 131.520 0.363 3960,000 26.900 0.035 3992,000 132.440 0.290 3981,000 23.360 0.026 4008,000 131.280 0.278 4000,000 16.560 0.011 4024,000 128.530 0.268 4017,000 11.410 0.007 4041,000 125.900 0.257 4036,000 8.880 0.005 4057,000 125.970 0.258 4055,000 7.620 0.004 4074,000 123.270 0.249 4072,000 6.990 0.004 4090,000 120.660 0.244 4091,000 6.510 0.003 4,106,000 120,330 0.242 4,108,000 6.330 0.003 4,123,000 118,780 0.240 4,127,000 6.040 0.003 4,139,000 117.030 0.23 6 4,148,000 5,850 0.003 4,160,000 136.210 0.385 4,165,000 5.860 0.003 4,282,000 146,290 0.488 4,184,000 5,880 0.003 4,409,000 141.190 0.478 4,207,000 5.910 0.004 4,536,000 138,780 0.476 4,331,000 6.060 0.004 4,663,000 139.040 0.480 4455,000 6.250 0.004 4790,000 135.570 0.480 4577,000 6.350 0.004 4916,000 135.500 0.480 4701,000 6.480 0.004 5043,000 134.280 0.474 4823,000 6.670 0.004 5170,000 133.330 0.471 4947,000 6.780 0.004 5297,000 132,320 0.472 5071,000 7,000 0.004 5,424,000 131,930 0.473 5,193,000 7,130 0.004 5,551,000 131,190 0.474 5,317,000 7,070 0.004 5,678,000 130,270 0.474 5,440,000 7,060 0.005 5,564,000 7,480 0.004 5,688,000 7,140 0.004 FIG 3a (continued) ) FIG 3b
t P50 Vc t P50 Vc
0,000 0,000
19,000 303,710 0.783 19,000 301,590 1,313
37,000 305,130 1,612 42,000 294,650 1,349
59,000 299,330 1,489 63,000 293,800 1,302
82,000 296,390 1,873 86,000 293,630 1,305
106,000 297,310 1,914 110,000 293,740 1,300
127,000 297,100 1,950 131,000 295,090 1,275
150,000 296,900 1,979 154,000 294,790 1,264
172,000 296,530 2,021 175,000 294,670 1,249
195,000 296,590 2,005 199,000 295,680 1,304
218,000 296,620 2,035 222,000 295,530 1,302
240,000 296,410 2,021 243,000 295,200 1,308
263,000 297,060 1,993 266,000 295,170 1,302
303,000 296,150 2,059 294,000 294,840 1,301
431,000 295,610 2,053 422,000 294,850 1,309
560,000 295,200 2,064 551,000 294,240 1,273
686,000 295,290 2,032 677,000 293,960 1,265
815,000 295,220 806,000 294,080 1,280
941,000 294,480 2,031 932,000 293,310 1,260 1,070,000 294,610 2,062 1,060,000 293.080 1,258 1,198,000 294.310 2,030 1,189,000 293.440 1.270 1,325,000 294.090 2,033 1,315,000 292,780 1,250 1,453,000 294,420 2,024 1,443,000 292,930 1,259 1,580,000 294.1 1,985 1,570,000 292,700 1,240 1,708,000 294,260 1.994 1,698,000 292,280 1,240 1,837,000 294,340 2,010 1,826,000 1979,000 294.1110 2,000 1992,000 292,100 1,179 2002,000 293,390 1,979 2015,000 294,410 1,154 2026,000 292,990 1,880 2039 , 000 294.980 1.147 2047,000 292,610 1,847 2,060,000 295,000 1,146 2,070,000 292,450 1,819 2,083,000 295.320 1,147 2,094,000 292.020 1.799 2,106,000 295.280 1,135 2,115,000 291.910 1,789 2,128,000 295.280 1,128 2,139,000 291,660 1,768 2,151 , 000 294.870 1.124 2160,000 291.580 1.760 2172,000 297.460 1.180 2184,000 291.530 1.748 2195,000 297.960 1.222 2207,000 291.360 1.760 2219,000 297.360 1.222 2229,000 291.390 1.776 2240,000 296.900 1.231 2250,000 291.480 1.771 2263 .000 296.760 1.226 2286,000 291.150 1.765 2288,000 296.520 1.222 FIG 3a (continued) FIG 3b
t P50 Vc t P50 Vc 2415,000 290,890 1,783 2,417,000 295,790 1,224 2,543,000 290,930 1,773 2,545,000 295,390 1,238 2,670,000 290,780 1,754 2,672,000 295,340 1,254 2,799,000 292,150 1,749 2800,000 294,760 1,240 2925,000 292,220 1,760 2,926,000 294,390 1,241 3,053,000 292,060 1,759 3,055,000 293,880 1,233 3,182,000 291.030 1.753 3,183,000 293,450 1,245 3,308,000 291.930 1.756 3,309,000 293,120 1,254 3,436,000 291,790 1,767 3,437,000 292,300 1,233 3,563,000 291.610 1,767 3,564,000 292,040 1,229 3,692,000 291,790 1,766 3692,000 291,390 1,231 3,821,000 291,650 1,745 3,820,000 290.1110 1.228 3975,000 291.510 1.755 3966,000 288.170 1.224 3998,000 289.230 1.757 3990,000 291.300 1.104 4018,000 289.020 1,559 4013,000 288,710 1,080 4039,000 288,810 1,429 4034,000 291,910 1,076 4063,000 288,810 1,386 4057,000 289,920 1,056 4087,000 288,760 1,360 4081,000 288,540 1,035 4108,000 288,810 1,333 4102,000 288,190 1,032 4131,000 288,370 1,329 4,125,000 287,580 1,021 4,153,000 288,690 1,320 4,147,000 287,470 1,024 4,176,000 288,670 1,305 4,170,000 300,200 1,211 4,202,000 289.590 1,308 4,193,000 299,370 1,222 4,224,000 289.440 1.384 4,215,000 298.790 1.227 4247,000 289.380 1.393 4238,000 298.320 1.228 4285,000 289.120 1.390 4282,000 297.750 1.231 4414,000 288.750 1,396 4,411,000 297,520 1,230 4,542,000 288,660 1,389 4,539,000 296,550 1,231 4,669,000 288.770 1,387 4,666,000 296.320 1.252 4,797,000 288.490 1.383 4,794,000 295,600 1,249 4,924,000 288.310 1.376 4,920,000 294,250 1,234 5,053,000 288.160 1,380 5,049,000 293,880 1,224 5,181,000 288.080 1,375 5,177,000 294.052 1,237 5,308,000 287,430 1,377 5,304,000 293,250 1,235 5,436,000 287.330 1,370 5,432,000 292,820 1,231 5,563,000 286,700 1,368 5,558,000 290,560 1,221 5,691,000 286.830 1,369 5,687,000 289,370 1,234 5,810,000 286,340 1,384 5,815,000 288,460 1,231 FIG 4a (continued) FIG 4b
t P50 Vc t P50 Vc
0,000 0,000
11,000 17,000 310,990 0.858
21,000 169,560 0.041 40,000 292,950 0.948
32,000 342,780 0.614 62,000 291,900 0.901
47,000 300,160 0.785 84,000 291,670 0.880
63,000 295,820 0.821 106,000 291,600 0.864
78,000 295.070 0.809 128,000 293,000 0.851
93,000 296,880 0.047 150,000 292,480 0.840
108,000 297,050 0.853 172,000 292,370 0.843
123,000 301,880 0.911 195,000 297,570 0.904
139,000 301,790 0.919 217,000 298,300 0.904
154,000 302,590 0.895 239,000 298,270 0.906
169,000 303,000 0.911 261,000 298.490 0.908
184,000 306,350 0.915 294,000 298,480 0.909
304,000 301,080 0.913 422,000 299.510 0.905
425,000 310,320 0.898 550,000 298,470 0.895
545,000 310,440 0.900 677,000 298,630 0.885
666,000 309,970 0.879 805,000 298,040 0.888
786,000 309,980 0.867 932,000 295,480 0.866
906,000 309.890 0.891 1059,000 292.040 0.857 1027,000 309.430 0.885 1187,000 288.510 0.847 1,147,000 308.520 0.891 1,314,000 286.770 0.847 1,267,000 308.460 0.864 1,442,000 283.510 0.835 1,387,000 307,190 0.857 000 307.010 0.853 1695,000 265.130 0.790 1609,000 307.1110 0.844 1822,000 266.480 0.798 1965,000 286.740 0.773 1963,000 260.330 0.776 1981,000 280.620 0.745 1986,000 211,250 0.675 1996,000 263.650 0.701 2008,000 218,940 0.667 2011, 000 253.760 0.677 2030,000 223.030 0.665 2027,000 238.670 0.663 2052,000 227.760 0.667 2042,000 240.140 0.664 2075,000 229.400 0.666 2057,000 212.920 0.632 2097,000 231.530 0.664 2072,000 216.030 0.639 2119,000 229.420 0.658 000 216.210 0.631 2,140,000 224,050 0.642 2,103,000 191,890 0.608 2,163,000 250,750 0.708 2,119,000 201.1110 0.621 2,186,000 299.970 0.848 2,134,000 191.880 0.605 2,207,000 299,930 0.857 2,149,000 212,610 0.628 2,230,000 299.280 0.84 2168, 000 238.520 0.660 2257,000 298.950 0.853 FIG 4a (continued) FIG 4b
t P50 Vc t P50 Vc 2288,000 226,090 0.651 2,513,000 297,930 0.849 2,409,000 231,740 0.660 2,640,000 292.010 0.827 2,529,000 233,250 0.652 2768,000 287.310 0.816 2650,000 216.270 0.650 2894,000 283.990 0.811 2770,000 206.720 0.641 3022,000 284.080 0.808 2890,000 196,930 0.637 3,150,000 276.710 0.791 3,011,000 192,480 0.634 3,277,000 275.310 0.786 3,131,000 180.300 0.628 3,405,000 261.370 0.756 3251,000 183.470 0.637 3,532,000 260,620 0.757 3,371,000 175,990 0.632 3659,000 260.040 0.752 3492,000 168,920 0.625 3,787,000 3,613,000 160,600 0.613 3,941,000 252,200 0.743 3,987,000 164,140 0.615 3,964,000 193,740 0.612 4,003,000 137,270 0.480 3,987,000 185.380 0.531 4,018,000 132,040 0.411 4,008 .000 188.320 0.525 4033,000 129.500 0.377 4031,000 196.450 0.533 4044,000 130.400 0.370 4053,000 197.130 0.528 4055,000 130.160 0.360 4075,000 198.1110 0.522 4066,000 129.020 0.353 4092,000 199.040 0.524 4077,000 128.770 0.347 4109 , 000 199.630 0.521 4087,000 128.310 0.341 4126,000 201,000 0.520 4098,000 126.570 0.332 4143.00 0 221,400 0.609 4109,000 126.980 0.330 4165,000 302.280 0.840 4120,000 127.950 0.331 4187,000 302.350 0.841 4131,000 127.790 0.330 4216,000 300.960 0.844 4172,000 126.230 0.316 4344,000 299.890 0.850 4288,000 180,190 0.529 4472, 000 297.980 0.844 4409,000 177.980 0.530 4599,000 296.770 0.841 4529,000 173.050 0.520 4727,000 293.020 0.837 4649,000 166.880 0.502 4854,000 287.650 0.828 4769,000 168.230 0.504 4981,000 283.150 0.812 4890,000 162.960 0.494 5109. 000 281.430 0.805 5010,000 162,160 0.490 5,236,000 279.280 0.802 5,130,000 160.540 0.482 5,364,000 276,850 0.804 5,251,000 159.030 0.485 5,491,000 275.020 0.799 5,371,000 153,790 0.467 5,619,000 269.360 0.778 5,492,000 152,920 0.470 5,747 000 268.030 0.775 5612,000 151.660 0.469 FIG 5a (continued) FIG 5b
t P50 Vc t P50 Vc
0,000 0,000
18,000 302,370 0.336 11,000 121,000 0.011
35,000 299,790 1,009 23,000 293,950 0.786
56,000 305,760 0.154 37,000 294,510 0.810
77,000 309,170 0.182 53,000 294.1110 0.792
99,000 310,180 0.195 69,000 293,850 0.808
120,000 309,590 0.197 83,000 294,000 0.821
141,000 310,180 0.186 99,000 292,050 0.804
162,000 309,320 0.187 114,000 292,140 0.804
184,000 309,520 0.165 129,000 292.180 0.798
205,000 309,960 0.091 145,000 291.610 0.764
227,000 309,660 0.122 160,000 291,790 0.777
248,000 308,870 0.106 176,000 291,720 0.781
291,000 308,970 0.072 209,000 300,230 0.844
418,000 308,800 0.072 330,000 300,860 0.849
544,000 308,710 0.047 451,000 300,740 0.842
670,000 308.310 0.049 671,000 300,800 0.830
797,000 308,300 0.035 691,000 300,600 0.829
923,000 308,200 0.036 812,000 300,910 0.829 1,049,000 308,220 0.025 932,000 300,690 0.828 1,176,000 307,950 0.028 1,053,000 300.810 0.838 1,303,000 307,770 0.022 1,173,000 300,540 0.839 1,429,000 307,880 0.008 1,293,000 300,470 0.818 1,555,000 308.370 0.0 .000 300.570 0.822 1681,000 308.650 0.004 1534,000 300.640 0.824 1808,000 308.430 0.002 1655,000 300.590 0.821 1981,000 308.310 0.002 1976,000 300,140 0.814 2003,000 308,390 0.973 1992,000 291,760 0.760 2,025,000 308,220 0.957 2007 , 000 288.720 0.712 2046,000 307.590 0.943 2022,000 288.440 0.688 2067,000 308.060 0.941 2038,000 288.150 0.677 2089,000 307.730 0.930 2054,000 286.410 0.658 2110,000 307.430 0.927 2069,000 286.530 0.630 2132,000 307.030 , 000 286.900 0.618 2153,000 306.850 0.915 2090,000 283.560 0.604 2175,000 306.940 0.932 2101,000 278.480 0.577 2196.000 307.220 0.945 2113,000 277.930 0.553 2219,000 307.520 0.928 2123,000 271.140 0.530 2241,000 307.510 0.941 2134 , 000 282,200 0.537 2,267,000 307,440 0.941 2,157,000 263.1 30 0.477 FIG 5a (continued) FIG 5b
t P50 Vc t P50 Vc 2,393,000 307.610 0.927 2,274,000 294.550 0.769 2,520,000 307,650 0.927 2,394,000 296.380 0.776 2,646,000 307.510 0.935 2,514,000 295,400 0.778 2,773,000 307,640 0.927 2,635,000 295,890 0.785 2,899,000 307,730 0.924 2755,000 296,130 0.758 3,026,000 307,660 0.922 2,876,000 295.820 0.763 3,153,000 307.520 0.922 2,997,000 295.830 0.759 3279,000 307.550 0.910 3,117,000 296.880 0.753 3,405,000 307,720 0.909 3,237,000 295,190 0.7566031 0.910 3357,000 294.890 0.767 3658,000 307.640 0.907 3478,000 293.930 0.761 3785,000 307.580 0.930 3599,000 293.940 0.738 3953,000 307.630 0.927 3957,000 293.770 0.733 3974,000 305,500 0.892 3973,000 251.690 0.77530 0.824 3985,000 229,950 0.329 4017,000 291,070 0.791 3995,000 219.310 0.288 4039,000 291.460 0.766 4006,000 202.440 0.246 4061,000 292,200 0.734 4018,000 198.220 0.29 4081,000 293.570 0.715 4028,000 189.260 0.208 4103,000 293.340 0.689 4039,000 178,000 0.184 4,124,000 294,680 0.668 4,050,000 170,400 0.167 4,145,000 295,440 0.680 4061,000 162,800 0.150 4,167,000 291.910 0.775 4,073,000 149,700 0.131 4,188,000 292.030 0.792 4,084,000 149.340 0.125 4,210,000 292.020 0.795 4,095,000 138.080 0.111 4,236,000 293.990 0.797 4,122,000 129.350 0.085 4,363,000 294.570 0.791 4238,000 297.260 0.589 4489,000 294.830 0.785 4355,000 290.010 0.605 4615,000 296.690 0.783 4471,000 291.560 0.615 4742,000 297.200 0.775 4587,000 280.1110 0.578 4868,000 297,000 0.770 4702,000 282.710 0.590 4995,000 297.400 0.768 4819,000 279.690 0.585 5122,000 297.370 0.766 4935,000 279.540 0.578 5248,000 296.940 0.755 5051,000 278.680 0.588 5374,000 297.480 0.760 5167,000 277.800 0.583 5500,000 298.370 0.746 5282,000 274.500 0.575 5627,000 298.160 0.750 5,399,000 276,730 0.584 5,753,000 298,690 0.752 5,515,000 265,540 0.577

Claims (14)

REVENDICATIONS 1.- Procédé de coagulation-floculation d'une suspension agrégative et contenant un coagulant, comprenant au moins, à l'instant initial, un cycle opératoire initial consistant en: 1.- Method of coagulation-flocculation of an aggregative suspension and containing a coagulant, comprising at least, at the initial instant, an initial operating cycle consisting of: (i) une étape d'agitation rapide avec un gradient de vélo (i) a rapid agitation stage with a bicycle gradient cité moyenne compris entre 300 et 1 000 s 1, pendant average city between 300 and 1000 s 1, during une durée comprise entre 30 et 200 s; et a duration between 30 and 200 s; and (ii) une étape d'agitation lente avec un gradient de vélo -1 (ii) a slow agitation step with a gradient of cycling -1 cité moyenne compris entre 40 et 100 s , pendant une  average city between 40 and 100 s, during a durée comprise entre 5 et 40 mn. duration between 5 and 40 min. 2.- Procédé selon la revendication 1, caractérisé en ce que le gradient de vélocité moyenne de l'étape d'agitation rapide est d'environ 450 2.- Method according to claim 1, characterized in that the average velocity gradient of the rapid stirring step is approximately 450 3.- Procédé selon la revendication 1 ou 2, caractérisé en ce que la durée de l'étape d'agitation rapide est d'environ 180 s. 3.- Method according to claim 1 or 2, characterized in that the duration of the rapid stirring step is approximately 180 s. 4.- Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce que le gradient de vélocité moyenne de l'étape d'agitation lente est d'environ 85 4.- Method according to any one of the preceding claims, characterized in that the average velocity gradient of the slow stirring step is approximately 85 5.- Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce que la durée de l'étape d'agitation lente est d'environ 30 mn. 5.- Method according to any one of the preceding claims, characterized in that the duration of the slow stirring step is approximately 30 min. 6.- Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce que le coagulant est choisi dans le groupe consistant en FeC13, polychlorure d'aluminium (PAC), Al2(S04)3, et leurs mélanges. 6.- Method according to any one of the preceding claims, characterized in that the coagulant is chosen from the group consisting of FeC13, poly aluminum chloride (PAC), Al2 (SO4) 3, and their mixtures. 7.- Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce que le pH de la suspension est compris entre 5 et 9, de préférence entre 5,5 et 8.5. 7.- Method according to any one of the preceding claims, characterized in that the pH of the suspension is between 5 and 9, preferably between 5.5 and 8.5. 8.- Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce qu'il comprend, outre ledit cycle opératoire initial, au moins un cycle, de préférence deux cycles, opératoire(s) supplémentaire(s). 8.- Method according to any one of the preceding claims, characterized in that it comprises, in addition to said initial operating cycle, at least one cycle, preferably two cycles, additional operating mode (s). 9.- Procédé selon la revendication 8, caractérisé en ce que le gradient de vélocité moyenne de l'étape d'agitation rapide est augmenté d'un cycle au cycle suivant. 9.- Method according to claim 8, characterized in that the average velocity gradient of the rapid stirring step is increased from one cycle to the next cycle. 10.- Procédé selon la revendication 8, caractérisé en ce que le gradient de vélocité moyenne de l'étape d'agitation rapide est augmenté d'au moins environ 225 s 1 d'un cycle au cycle suivant. 10.- Method according to claim 8, characterized in that the average velocity gradient of the rapid stirring step is increased by at least about 225 s 1 from one cycle to the next cycle. 11.- Procédé selon l'une quelconque des revendications 8 à 10, caractérisé en ce que le gradient de vélocité moyenne de l'étape d'agitation lente reste substantiellement constant au cours des différents cycles. 11.- Method according to any one of claims 8 to 10, characterized in that the average velocity gradient of the slow stirring step remains substantially constant during the various cycles. 12.- Procédé selon l'une quelconque des revendications 8 à 11, caractérisé en ce que la durée de l'étape d'agitation rapide reste substantiellement constante d'un cycle au cycle suivant. 12.- Method according to any one of claims 8 to 11, characterized in that the duration of the rapid stirring step remains substantially constant from one cycle to the next cycle. 13.- Procédé selon l'une quelconque des revendications 8 à 12, caractérisé en ce que la durée de l'étape d'agitation lente reste substantiellement constante d'un cycle au cycle suivant. 13.- Method according to any one of claims 8 to 12, characterized in that the duration of the slow stirring step remains substantially constant from one cycle to the next cycle. 14.- Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce qu'il consiste en les 3 cycles (a),(b) et (c) suivants: 14.- Method according to any one of the preceding claims, characterized in that it consists of the following 3 cycles (a), (b) and (c): (a)(i) une étape d'agitation rapide avec un gradient de -l (a) (i) a rapid stirring step with a gradient of -l vélocité moyenne d'environ 450 s pendant une  average velocity of approximately 450 s during one durée d'environ 180 s; et duration of about 180 s; and (ii) une étape d'agitation lente avec un gradient de -l (ii) a slow stirring step with a gradient of -l vélocité moyenne d'environ 85 s 1 pendant une  average velocity of approximately 85 s 1 during a durée d'environ 30 mn; duration of approximately 30 min; (b)(i) une étape d'agitation rapide avec un gradient de -l (b) (i) a rapid stirring step with a gradient of -l vélocité moyenne d'environ 725 s pendant une  average velocity of approximately 725 s during durée d'environ 180 s; et duration of about 180 s; and (ii) une étape d'agitation lente avec un gradient de -l (ii) a slow stirring step with a gradient of -l vélocité moyenne d'environ 85 s 1 pendant une  average velocity of approximately 85 s 1 during a durée d'environ 30 mn; duration of approximately 30 min; (c)(i) une étape d'agitation rapide avec un gradient de -1 (c) (i) a rapid agitation step with a gradient of -1 vélocité moyenne d'environ 1000 s 1 pendant une  average velocity of approximately 1000 s 1 during a durée d'environ 180 s; et duration of about 180 s; and (ii) une étape d'agitation lente avec un gradient de -1 (ii) a slow stirring step with a gradient of -1 vélocité moyenne d'environ 85 s pendant une  average velocity of approximately 85 s during one durée d'environ 30 mn.  duration of approximately 30 min.
FR9308133A 1992-07-02 1993-07-02 New coagulation-flocculation process. Expired - Fee Related FR2694706B1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0712657A1 (en) * 1994-11-18 1996-05-22 The Yokohama Rubber Co., Ltd. Raw material mixing method and apparatus

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Publication number Priority date Publication date Assignee Title
FR2304572A2 (en) * 1975-03-19 1976-10-15 Polasek Pavel WATER CLARIFICATION
JPS63278509A (en) * 1987-05-11 1988-11-16 Ebara Infilco Co Ltd Method for controlling agitation of flocculation basin
FR2631021A1 (en) * 1988-05-05 1989-11-10 Omnium Traitement Valorisa Process for the purification of treatment of water, with a prolonged coagulation stage

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2304572A2 (en) * 1975-03-19 1976-10-15 Polasek Pavel WATER CLARIFICATION
JPS63278509A (en) * 1987-05-11 1988-11-16 Ebara Infilco Co Ltd Method for controlling agitation of flocculation basin
FR2631021A1 (en) * 1988-05-05 1989-11-10 Omnium Traitement Valorisa Process for the purification of treatment of water, with a prolonged coagulation stage

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Title
DATABASE WPI Section Ch Week 9131, Derwent World Patents Index; Class A97, AN 91225264 *
PATENT ABSTRACTS OF JAPAN vol. 13, no. 105 (C - 575) 13 March 1989 (1989-03-13) *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0712657A1 (en) * 1994-11-18 1996-05-22 The Yokohama Rubber Co., Ltd. Raw material mixing method and apparatus

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