WO1993009064A1 - Flocculation process - Google Patents

Flocculation process Download PDF

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Publication number
WO1993009064A1
WO1993009064A1 PCT/EP1992/002476 EP9202476W WO9309064A1 WO 1993009064 A1 WO1993009064 A1 WO 1993009064A1 EP 9202476 W EP9202476 W EP 9202476W WO 9309064 A1 WO9309064 A1 WO 9309064A1
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WO
WIPO (PCT)
Prior art keywords
calcium
compound
wastewater
carbon dioxide
flocculation
Prior art date
Application number
PCT/EP1992/002476
Other languages
German (de)
French (fr)
Inventor
Wolfgang Berke
Original Assignee
Henkel Kommanditgesellschaft Auf Aktien
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Publication date
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Publication of WO1993009064A1 publication Critical patent/WO1993009064A1/en

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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
    • C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents

Definitions

  • the invention relates to a process for flocculating a finely divided inorganic or organic synthetic substance from the aqueous phase, in particular in wastewater treatment.
  • wastewater with inorganic and organic components is generally cleaned as follows: a) A computing unit removes coarse solids. b) Light liquids are separated in a separator. c) The pH is adjusted to approx. 7 with NaOH or H2SO4 in order to precipitate heavy metal ions and phosphates. d) The precipitation is further completed by the addition of precipitants and flocculants. The solids are removed after their sedimentation and, depending on their nature, further treated, e.g. deposited as hazardous waste or used as a valuable material. e) The treated wastewater is still biologically cleaned, e.g. in that the remaining organic compounds are broken down aerobically and / or anaerobically.
  • one or more stages can be omitted without missing the main objectives of cleaning, namely a) to improve the quality of the wastewater in such a way that it can either be recycled or discharged into the public sewerage system without damage, and b) to recover valuable materials.
  • Waste water with finely divided organic and inorganic substances is very common in industry, e.g. in the manufacture and processing of lacquers, emulsion paints, wallpapers, adhesives, fibers, carpets, textiles, dyes, pigments, rubber, oil, lubricants, greases, waxes etc.
  • the waste water can contain very little solids, e.g. Waste water from rinsing and cleaning processes, as well as very much, e.g. a mud-like soil.
  • such wastewater typically contains:
  • Base polymer e.g. polystyrene-butadiene, polyvinyl acetate, polyvinyl alcohol, polyolefin, polyvinyl chloride, polyacrylates, polymethacrylates and epoxy resins with additives such as plasticizers (e.g. dibutyl phthalate), protective colloids: PVA, HEC r dextrins, hydroxyethyl starch, emulsifiers: nonylphenol ethoxylates, fatty alcohol fillers, colorants, fillers, colorants, coloring agents, colorants, fillers, colorants, colorants, fillers, colorants, colorants, fillers, colorants, colorants, coloring agents, fillers, colorants, colorants, fillers: .
  • plasticizers e.g. dibutyl phthalate
  • protective colloids PVA, HEC r dextrins, hydroxyethyl starch
  • emulsifiers nonylphenol ethoxylates
  • the components in solid or liquid form (suspensions or emulsions) which are finely divided, ie molecularly, colloidally or coarsely dispersed, can be removed by filtration, sedimentation, centrifugation or else by flocculation from the aqueous phase.
  • Flocculation or flocculation is understood to mean the removal of undesired constituents by the formation of sparingly soluble substances in the form of flakes, whether by coalescence, occultation or Adsorption.
  • a liquid clouded by dispersed particles is clear again. This is achieved primarily with the aid of suitable additives (flocculants or clarifiers) on inorganic electrolytes with polyvalent cations, for example iron and aluminum chloride or sulfate and calcium hydroxide, or by adding macromolecular organic polyelectrolytes based on polyacrylic acid, polyacrylamide, Polyethylene oxide, polyethylene imine, etc.
  • adsorption processes in the particle surfaces break down the potential barriers that hinder flocculation.
  • the particles are additionally crosslinked by the filiform molecules of the flocculant, the binding-active groups of which interact with the particle surfaces.
  • hydroxide precipitates An essential factor for a successful clarification effect in conventional processes is the formation of hydroxide precipitates.
  • the metering of increasing amounts of aluminum or iron salt at approximately neutral pH values leads to hydroxide flakes which occur when they are formed or subsequently Can bind the remaining turbidity through adsorption and inclusion (precipitation flocculation).
  • the resulting products are highly water-containing, amorphous hydroxides, which have only low flake strength and are difficult to separate and dewater by sedimentation or filtration.
  • the pH value is corrected by adding lime.
  • Calcium also leads to precipitation such as CaSOj, which improves separation as a filler.
  • the object of the invention consists in particular in reducing or even eliminating these disadvantages, and in general in improving the effectiveness and economy of the flocculation.
  • the solution according to the invention can be found in the patent claims. It essentially consists of flocculation with poorly soluble calcium compounds in situ.
  • the flocculation according to the invention is characterized by the addition of a polyvalent electrolyte, a calcium compound and a carbon compound, which gives a poorly soluble reaction product with calcium, to an aqueous liquid with finely divided inorganic or organic substances.
  • polyvalent electrolytes are known flocculants, that is to say inorganic electrolytes with 2- and in particular trivalent cations such as calcium, magnesium, iron, aluminum or organic polyelectrolytes, in particular cationic polyelectrolytes.
  • inorganic electrolytes with 2- and in particular trivalent cations such as calcium, magnesium, iron, aluminum or organic polyelectrolytes, in particular cationic polyelectrolytes.
  • Such substances are commercially available, for example under the name Sachtopur-S, Sachtoklar (Sachtleben Chemie, Duisburg), Quickfloc, Ferrifloc (Kronos, Langenfeld), P3-Ferrocryl, P3-Ferrolin (Henkel, Düsseldorf) , Rohafloc (Röhm, Darmstadt).
  • the electrolytes are added in the concentrations specified by the manufacturer, for example 5 to 500 g / ⁇ solids in the waste water. Coagulation can also be achieved by lowering the pH, especially by gassing with carbon dioxide.
  • the dispersion or the emulsion can be cleaved at a higher temperature.
  • the calcium compounds are water-soluble or colloidally dispersed calcium compounds such as calcium chloride, calcium hydroxide, calcium oxide.
  • Lime milk and lime water are preferred, in particular calcium oxide or calcium hydroxide (ie dry substances). Burnt or slaked lime is the cheapest source of calcium and is available everywhere in large quantities.
  • the calcium compound can be added to the aqueous liquid before and / or after coagulation with the polyvalent electrolyte; it can also serve to set an optimal pH.
  • the calcium compound is precipitated in situ by the addition of a carbon compound.
  • the carbon compound is said to produce a poorly soluble reaction product with the calcium.
  • carboxylic acids in particular monocarboxylic acids, and polyols, in particular amino acids or proteins.
  • an addition of carbon dioxide is preferred.
  • the acids, in particular the CO2 are added until the pH is in the weakly alkaline range, in particular until it is approximately 8.7 to 9.
  • the Calcium compound and the carbon dioxide can be metered in successively, alternately in several stages or simultaneously (continuously).
  • the precipitation flocculation with the sparingly soluble calcium salt or complex can be repeated or carried out until the aqueous liquid is no longer cloudy or has the desired purity.
  • the course of the titratation with the carbonic acid allows the pH of the liquid to be set precisely.
  • the process according to the invention can be carried out both at room temperature and at elevated temperature. It is therefore possible to clarify with liquids at the temperature of 10 to 80 ° C. which is produced.
  • the process components according to the invention are added and distributed using conventional devices, for example the electrolytes are added by freshly preparing a working solution according to the manufacturer's instructions, for example from a stock solution or the undiluted electrolyte, and mixing it intensively into the water to be treated.
  • the calcium compound is added by preparing a working solution and mixing it intensively into the water to be treated, for example by producing lime milk from burnt or extinguished lime.
  • the use of solid substances, for example by sprinkling salts into the water to be treated, is possible, but usually requires additional consumption.
  • the carbon dioxide is added by Introduces carbon dioxide gas into the preferably alkaline solution. Simple gassing devices for containers or pipes are sufficient.
  • a soluble hydrogen carbonate or carbonate preferably sodium hydrogen carbonate, can be dissolved or added to the water as a solid.
  • the control of the pH value is the decisive factor in all steps.
  • the optimal pH is between 10.8 and 11.2.
  • the pH should not fall below 8.7. This also applies to a gradual, changing dosage of the reagents.
  • the process according to the invention can be used to clarify aqueous liquids with finely divided inorganic or organic synthetic substances, in particular fully synthetic substances.
  • Aqueous dispersions with such substances are stabilized with dispersants.
  • dispersants These are water-soluble polymers as protective colloids and emulsifiers.
  • Polymers are natural products such as alginates, tragacanth, agar-agar, dextrins and starch, modified natural polymers such as carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, hydroxyethyl starch and synthetic polymers such as copolymers styrene / maleic anhydride, polymethacrylate, polyvinyl pyrrolidone, polyvinyl alcohol, partially saponified polyvinyl acetate, etc.
  • Emulsifiers are, in particular, anionic surfactants such as alkanesulfonates and fatty alcohol ether sulfates or nonionic surfactants such as nonylphenol oxethylates.
  • the flocculation process according to the invention is particularly suitable for cleaning industrial wastewater.
  • These industrial wastewater are generally characterized by the presence of a stabilized emulsion or dispersion of inorganic or organic synthetic substances, which cannot be purified solely by using polyvalent electrolytes.
  • the solubility of the precipitate is extremely low.
  • the solid has a high density and can be sedated or filtered quickly. Since the separation of the solid determines the grain size, it can easily be influenced by the type and duration of the addition of carbon dioxide.
  • Waste water from a plant producing and processing PVAc dispersions (washing and rinsing water) with a dry matter content of 28 g / 1 (s 28 kg / m 3 ).
  • the filtrate was clear.
  • the filtration of the solid from the liquid took only half as long as in a conventional cleaning process using only an electrolyte and a lime compound.

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  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (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)
  • Separation Of Suspended Particles By Flocculating Agents (AREA)

Abstract

The description relates to a process for flocculating a finely devided organic or inorganic synthetic substance from an aqueous liquid in which a multivalent electrolyte, a calcium compound and a carbon compound which, with calcium, gives a reaction product which is difficult to dissolve are added to the liquid. Ferric salts, burnt lime and CO2 are preferably used. It is thus possible to clear mainly waste water from stabilised dispersions of fully synthetic polymers.

Description

"Ausflockung" "Flocculation"
Die Erfindung betrifft ein Verfahren zum Ausflocken eines feinver¬ teilten anorganischen oder organischen synthetischen Stoffes aus der wäßrigen Phase, insbesondere bei der Abwasserreinigung.The invention relates to a process for flocculating a finely divided inorganic or organic synthetic substance from the aqueous phase, in particular in wastewater treatment.
Bekanntlich werden Abwasser mit anorganischen und organischen Be¬ standteilen im allgemeinen folgendermaßen gereinigt: a) Ein Rechenaggregat entfernt grobe Feststoffe. b) In einem Abscheider werden leichte Flüssigkeiten abgetrennt. c) Der pH-Wert wird mit NaOH oder H2SO4 auf ca. 7 eingestellt, um Schwermetallionen und Phosphate auszufällen. d) Durch Zusatz von Fällungs- und Flockungsmitteln wird die Aus- fällung weiter vervollständigt. Die Feststoffe werden nach ih¬ rer Sedimentation entfernt und je nach Beschaffenheit weiter¬ behandelt, z.B. als Sondermüll deponiert oder als Wertstoff verwendet. e) Das geklärte Abwasser wird noch biologisch gereinigt, z.B. in¬ dem die noch verbliebenen organischen Verbindungen aerob und/oder anaerob bakteriell abgebaut werden.As is known, wastewater with inorganic and organic components is generally cleaned as follows: a) A computing unit removes coarse solids. b) Light liquids are separated in a separator. c) The pH is adjusted to approx. 7 with NaOH or H2SO4 in order to precipitate heavy metal ions and phosphates. d) The precipitation is further completed by the addition of precipitants and flocculants. The solids are removed after their sedimentation and, depending on their nature, further treated, e.g. deposited as hazardous waste or used as a valuable material. e) The treated wastewater is still biologically cleaned, e.g. in that the remaining organic compounds are broken down aerobically and / or anaerobically.
Je nach Herkunft des Abwassers aus Haushalten, Gewerbe oder Indu¬ strie können eine oder mehrere Stufen weggelassen werden, ohne daß die Hauptziele der Reinigung verfehlt werden, nämlich a) die Beschaffenheit des Abwassers so zu verbessern, daß es ent¬ weder wiederverwertet oder schadlos in die öffentliche Kanali¬ sation geleitet werden kann und b) WertStoffe zurückzugewinnen.Depending on the origin of the wastewater from households, trade or industry, one or more stages can be omitted without missing the main objectives of cleaning, namely a) to improve the quality of the wastewater in such a way that it can either be recycled or discharged into the public sewerage system without damage, and b) to recover valuable materials.
So sind die Industrie-Abwasser in der Regel einheitlicher, und es genügt häufig, den Verfahrensschritt d) an Ort und Stelle vorzu¬ nehmen.For example, industrial wastewater is generally more uniform, and it is often sufficient to carry out process step d) on the spot.
In der Industrie fallen Abwasser mit feinverteilten organischen und anorganischen Stoffen sehr häufig an, z.B. bei der Herstellung und Verarbeitung von Lacken, Dispersionsfarben, Tapeten, Klebstoffen, Fasern, Teppichen, Textilien, Farbstoffen, Pigmenten, Gummi, Öl, Schmiermittel, Fetten, Wachsen usw.. Das Abwasser kann sowohl sehr wenig Feststoffe enthalten, z.B. Abwasser von Spül- und Reini¬ gungs-Vorgängen, als auch sehr viel, z.B. ein schlammartiger Bo¬ densatz. Ein solches Abwasser enthält am Beispiel einer Dispersion typischerweise:Waste water with finely divided organic and inorganic substances is very common in industry, e.g. in the manufacture and processing of lacquers, emulsion paints, wallpapers, adhesives, fibers, carpets, textiles, dyes, pigments, rubber, oil, lubricants, greases, waxes etc. The waste water can contain very little solids, e.g. Waste water from rinsing and cleaning processes, as well as very much, e.g. a mud-like soil. Using the example of a dispersion, such wastewater typically contains:
Basispolymer: z.B. Polystyrol-Butadien, Polyvinylacetat, Polyvinylalkohol, Polyolefin, Polyvinylchlorid, Polyacrylate, Polymethacrylate und Epoxidharze mit Zuschlagstoffen wie Weichmachern (z.B. Dibutylphthalat), Schutzkolloide: PVA, HECr Dextrine, Hydroxyethylstärke, Emulgatoren: Nonylphenoloxethylaten, Fettalkoholethersulfate, Füllstoffe: Kreide, Farbpigmente. Die darin feinverteilten, d.h. molekular-, kolloidal- oder grob¬ dispers verteilten Bestandteile in fester oder flüssiger Form (Suspensionen oder Emulsionen) können durch Filtration, Sedimenta¬ tion, Zentrifugieren oder aber durch Ausflocken aus der wäßrigen Phase entfernt werden.Base polymer: e.g. polystyrene-butadiene, polyvinyl acetate, polyvinyl alcohol, polyolefin, polyvinyl chloride, polyacrylates, polymethacrylates and epoxy resins with additives such as plasticizers (e.g. dibutyl phthalate), protective colloids: PVA, HEC r dextrins, hydroxyethyl starch, emulsifiers: nonylphenol ethoxylates, fatty alcohol fillers, colorants, fillers, colorants, coloring agents, colorants, fillers, colorants, colorants, fillers, colorants, colorants, fillers, colorants, colorants, coloring agents, fillers, colorants, colorants, fillers: . The components in solid or liquid form (suspensions or emulsions) which are finely divided, ie molecularly, colloidally or coarsely dispersed, can be removed by filtration, sedimentation, centrifugation or else by flocculation from the aqueous phase.
Unter "Ausflocken bzw. Flocken" wird die Beseitigung unerwünschter Bestandteile durch Bildung von schwerlöslichen Substanzen in Flok- ken-Form verstanden, sei es durch Koaleszenz, Okkulation oder Adsorption. Eine durch dispergierte Teilchen getrübte Flüssigkeit wird dadurch wieder klar. Man erreicht das vor allem mit Hilfe ge¬ eigneter Zusätze (Flockungsmittel oder Klärmittel) an anorganischen Elektrolyten mit mehrwertigen Kationen, z.B. Eisen- und Alumini¬ um-Chlorid oder -Sulfat und Calciumhydroxid oder durch Zusatz makromolekularer organischer Polyelektrolyte auf Basis von Polyacrylsäure, Polyacrylamid, Polyethylenoxid, Polyethylenimin usw.. Im ersten Falle werden durch AdsorptionsVorgänge in den Teilchenoberflachen die Potentialbarrieren abgebaut, die die Flok- kung behindern. Im zweiten Fall erfolgt zusätzlich eine Vernetzung der Teilchen durch die fädchenförmigen Moleküle des Flockungsmit¬ tels, deren bindungsaktive Gruppen mit den Teilchenoberflächen in Wechselwirkung treten. Insgesamt kommt die Klärung der wäßrigen Flüssigkeit durch eine Reihe von einzelnen Effekte zustande:"Flocculation or flocculation" is understood to mean the removal of undesired constituents by the formation of sparingly soluble substances in the form of flakes, whether by coalescence, occultation or Adsorption. A liquid clouded by dispersed particles is clear again. This is achieved primarily with the aid of suitable additives (flocculants or clarifiers) on inorganic electrolytes with polyvalent cations, for example iron and aluminum chloride or sulfate and calcium hydroxide, or by adding macromolecular organic polyelectrolytes based on polyacrylic acid, polyacrylamide, Polyethylene oxide, polyethylene imine, etc. In the first case, adsorption processes in the particle surfaces break down the potential barriers that hinder flocculation. In the second case, the particles are additionally crosslinked by the filiform molecules of the flocculant, the binding-active groups of which interact with the particle surfaces. Overall, the clarification of the aqueous liquid comes about through a number of individual effects:
Entladung der (meist geladenen) Kolloide und Abbau der stabi¬ lisierenden elektrischen Grenzschichten,Discharge of the (usually charged) colloids and degradation of the stabilizing electrical boundary layers,
Koagulation der Suspensa,Coagulation of the Suspensa,
Ausfällung gelöster Substanzen,Precipitation of dissolved substances,
Flockung der Suspensa,Flocculation of the Suspensa,
Verdichtung der Feststoffe im Schlamm (Konditionierung) bis zu einer deponiefähigen Form.Compacting the solids in the sludge (conditioning) to a landfillable form.
Nur bei gut definierten Abwässern ohne wesentliche Mengen von sta¬ bilisierenden Schutzkolloiden führen allein die zur Ladungskompen¬ sation notwendigen Ionen durch Destabilisierung und Koagulation der Suspensa zum Erfolg. Andernfalls verbleibt ein erheblicher Trüb¬ stoffanteil in der wäßrigen Phase.Only with well-defined waste water without substantial amounts of stabilizing protective colloids can the ions necessary for charge compensation alone lead to success by destabilizing and coagulating the Suspensa. Otherwise, a considerable amount of turbidity remains in the aqueous phase.
Ein wesentlicher Faktor für eine erfolgreiche Klärwirkung besteht bei herkömmlichen Verfahren in der Bildung von Hydroxidniederschlägen. Die Dosierung von steigenden Mengen Alumi¬ nium- oder Eisensalz bei annähernd neutralen pH-Werten führt zu Hydroxidflocken, die bei ihrer Entstehung oder nachfolgendem Kontakt verbleibende Trübstoffe durch Adsorption und Einschluß binden können (Fällungsflockung). Die Entfernung dieser schwer zu flockenden Trübstoffe ist um so effektiver, je mehr Hydroxid ge¬ bildet wird. Die resultierenden Produkte sind stark wasserhaltige, amorphe Hydroxide, die nur geringe Flockenstärke aufweisen und sich durch Sedimentation oder Filtration nur schwer abtrennen und ent¬ wässern lassen.An essential factor for a successful clarification effect in conventional processes is the formation of hydroxide precipitates. The metering of increasing amounts of aluminum or iron salt at approximately neutral pH values leads to hydroxide flakes which occur when they are formed or subsequently Can bind the remaining turbidity through adsorption and inclusion (precipitation flocculation). The more hydroxide is formed, the more effective it is to remove these turbidities which are difficult to flocculate. The resulting products are highly water-containing, amorphous hydroxides, which have only low flake strength and are difficult to separate and dewater by sedimentation or filtration.
Durch die Zugabe von Kalk wird der pH-Wert korrigiert. Darüber hinaus führt Calcium zu Niederschlägen wie CaSOj, die als Füllstoff die Abtrennung verbessern.The pH value is corrected by adding lime. Calcium also leads to precipitation such as CaSOj, which improves separation as a filler.
Im Ergebnis entsteht eine große Menge Feststoff, der teuer entsorgt werden muß und zum überwiegenden Teil aus Fällungsmitteln besteht.The result is a large amount of solid, which has to be disposed of at high cost and consists predominantly of precipitants.
Die erfindungsgemäße Aufgabe besteht im einzelnen darin, diese Nachteile zu verringern oder gar zu beseitigen, und im allgemeinen darin, die Wirksamkeit und Wirtschaftlichkeit der Ausflockung zu verbessern.The object of the invention consists in particular in reducing or even eliminating these disadvantages, and in general in improving the effectiveness and economy of the flocculation.
Die erfindungsgemäße Lösung ist den Patentansprüchen zu entnehmen. Sie besteht im wesentlichen in der Ausflockung mit schwerlöslichen Calcium-Verbindungen in situ. Die erfindungsgemäße Ausflockung ist charakterisiert durch den Zusatz eines mehrwertigen Elektrolyten, einer Calcium-Verbindung und einer Kohlenstoff-Verbindung, die mit Calcium ein schwerlösliches Reaktionsprodukt ergibt, zu einer wä߬ rigen Flüssigkeit mit feinverteilten anorganischen oder organischen Stoffen.The solution according to the invention can be found in the patent claims. It essentially consists of flocculation with poorly soluble calcium compounds in situ. The flocculation according to the invention is characterized by the addition of a polyvalent electrolyte, a calcium compound and a carbon compound, which gives a poorly soluble reaction product with calcium, to an aqueous liquid with finely divided inorganic or organic substances.
Bei den "mehrwertigen Elektrolyten" handelt es sich um bekannte Flockungsmittel, also um anorganische Elektrolyte mit 2- und ins¬ besondere 3-wertigen Kationen wie Calcium, Magnesium, Eisen, Alu¬ minium oder um organische Polyelektrolyte, insbesondere um kationische Polyelektrolyte. Konkrete Beispiele sind Aluminiumchlorid, Polyaluminiumchlorid, Eisen(III)chlorid, Eisen¬ chloridsulfat, Polymere auf Basis Acrylsäureester und Acryla id. Derartige Stoffe sind im Handel erhältlich, z.B. unter dem Namen Sachtopur-S, Sachtoklar (Fa. Sachtleben Chemie, Duisburg), Quickfloc, Ferrifloc (Fa. Kronos, Langenfeld), P3-Ferrocryl , P3-Ferrolin (Fa. Henkel, Düsseldorf), Rohafloc (Fa. Röhm, Darm¬ stadt). Die Elektrolyte werden in den von den Hersteller angege¬ benen Konzentrationen zugesetzt, z.B. 5 bis 500 g/π Feststoff im Abwasser. Die Koagulation kann ebenso durch Absenken des pH-Wertes erreicht werden, insbesondere durch Begasen mit Kohlendioxid. Ins¬ besondere kann die Spaltung der Dispersion oder der Emulsion bei höherer Temperatur durchgeführt werden.The "polyvalent electrolytes" are known flocculants, that is to say inorganic electrolytes with 2- and in particular trivalent cations such as calcium, magnesium, iron, aluminum or organic polyelectrolytes, in particular cationic polyelectrolytes. There are concrete examples Aluminum chloride, polyaluminium chloride, iron (III) chloride, iron chloride sulfate, polymers based on acrylic acid esters and acrylic id. Such substances are commercially available, for example under the name Sachtopur-S, Sachtoklar (Sachtleben Chemie, Duisburg), Quickfloc, Ferrifloc (Kronos, Langenfeld), P3-Ferrocryl, P3-Ferrolin (Henkel, Düsseldorf) , Rohafloc (Röhm, Darmstadt). The electrolytes are added in the concentrations specified by the manufacturer, for example 5 to 500 g / π solids in the waste water. Coagulation can also be achieved by lowering the pH, especially by gassing with carbon dioxide. In particular, the dispersion or the emulsion can be cleaved at a higher temperature.
Bei den Calcium-Verbindungen handelt es sich um wasserlösliche oder kolloidal-dispergierte Calcium-Verbindungen wie Calciumchlorid, Calciumhydroxid, Calciu oxid. Bevorzugt werden Kalkmilch und Kalk¬ wasser, insbesondere Calciumoxid oder Calciumhydroxid (also Trok- ken-Substanzen). Gebrannter oder gelöschter Kalk ist die preis¬ werteste Calciumquelle und in großen Mengen überall verfügbar. Die Calcium-Verbindung kann vor und/oder nach der Koagulation mit dem mehrwertigen Elektrolyten der wäßrigen Flüssigkeit zugesetzt werden, sie kann auch zur Einstellung eines optimalen pH-Wertes dienen.The calcium compounds are water-soluble or colloidally dispersed calcium compounds such as calcium chloride, calcium hydroxide, calcium oxide. Lime milk and lime water are preferred, in particular calcium oxide or calcium hydroxide (ie dry substances). Burnt or slaked lime is the cheapest source of calcium and is available everywhere in large quantities. The calcium compound can be added to the aqueous liquid before and / or after coagulation with the polyvalent electrolyte; it can also serve to set an optimal pH.
Die Calcium-Verbindung wird durch den Zusatz einer Kohlenstoffver¬ bindung in situ ausgefällt. Die KohlenstoffVerbindung soll mit dem Calcium ein schwerlösliches Reaktionsprodukt ergeben. Dabei handelt es sich um Carbonsäuren, insbesondere um Monocarbonsäuren sowie um Polyole, insbesondere um Aminosäuren oder um Proteine. Bevorzugt ist aber ein Zusatz von Kohlendioxid. Die Säuren, insbesondere das CO2, werden zugesetzt, bis der pH-Wert im schwach alkalischen Be¬ reich liegt, insbesondere bis er bei ca. 8,7 bis 9 liegt. Die Calcium-Verbindung und das Kohlendioxid können nacheinander, ab¬ wechseln in mehreren Stufen oder gleichzeitig (kontinuierlich) zu¬ dosiert werden. Die Fällungsflockung mit dem schwerlöslichen Calciu salz bzw. -Komplex kann solange wiederholt bzw. durchgeführt werden, bis die wäßrige Flüssigkeit nicht mehr trüb ist bzw. die angestrebte Reinheit erhalten hat. Zum Schluß erlaubt der Titrati¬ onsverlauf mit der Kohlensäure eine genaue Einstellung des pH- Wertes der Flüssigkeit.The calcium compound is precipitated in situ by the addition of a carbon compound. The carbon compound is said to produce a poorly soluble reaction product with the calcium. These are carboxylic acids, in particular monocarboxylic acids, and polyols, in particular amino acids or proteins. However, an addition of carbon dioxide is preferred. The acids, in particular the CO2, are added until the pH is in the weakly alkaline range, in particular until it is approximately 8.7 to 9. The Calcium compound and the carbon dioxide can be metered in successively, alternately in several stages or simultaneously (continuously). The precipitation flocculation with the sparingly soluble calcium salt or complex can be repeated or carried out until the aqueous liquid is no longer cloudy or has the desired purity. Finally, the course of the titratation with the carbonic acid allows the pH of the liquid to be set precisely.
Kohlendioxid ist in großen Mengen überall verfügbar. Da es u.a. beim Kalkbrennen anfällt, ist für Kalk und Kohlendioxid ein voll¬ ständiger Stoffkreislauf möglich. Dabei werden die aus dem Wasser ausgefällten Stoffe mitverbrannt. Die Verbrennungsabgase, z.B. aus der betrieblichen Energieversorgung sind weitere preiswerte Quellen.Large quantities of carbon dioxide are available everywhere. Since it When lime is burned, a complete material cycle is possible for lime and carbon dioxide. The substances precipitated from the water are also burned. The combustion gases, e.g. from the operational energy supply are other inexpensive sources.
Das erfindungsgemäße Verfahren kann sowohl bei Raumtemperatur als auch bei erhöhter Temperatur durchgeführt werden. Es ist also mög¬ lich, mit Flüssigkeiten mit der bei der Herstellung anfallenden Temperatur von 10 bis 80 °C zu klären.The process according to the invention can be carried out both at room temperature and at elevated temperature. It is therefore possible to clarify with liquids at the temperature of 10 to 80 ° C. which is produced.
Die erfindungsgemäßen Verfahrenskomponenten werden mit üblichen Vorrichtungen zugesetzt und verteilt, z.B. gibt man den Elektro¬ lyten zu, indem eine Gebrauchslösung nach Angaben des Herstellers beispielsweise aus einer Stammlösung oder dem unverdünnten Elek¬ trolyt frisch hergestellt und intensiv in das zu behandelnde Wasser eingemischt wird. Die Calcium-Verbindung wird zugesetzt, indem eine Gebrauchslösung hergestellt und intensiv in das zu behandelnde Wasser eingemischt wird, beispielsweise durch Herstellen von Kalk¬ milch aus gebranntem oder gelöschtem Kalk. Die Verwendung von festen Stoffen, beispielsweise durch das Einstreuen von Salzen in das zu behandelnde Wasser, ist möglich, erfordert aber i.d.R. einen Mehrverbrauch. Das Kohlendioxid wird zugesetzt, indem man Kohlendioxidgas in die vorzugsweise alkalische Lösung einleitet. Dazu genügen einfache Begasungseinrichtungen für Behälter oder Rohrleitungen. Alternativ kann anstelle von Kohlendioxidgas ein lösliches Hydrogencarbonat oder Carbonat, vorzugsweise Natriumhydrogencarbonat gelöst oder als Feststoff dem Wasser zuge¬ setzt werden.The process components according to the invention are added and distributed using conventional devices, for example the electrolytes are added by freshly preparing a working solution according to the manufacturer's instructions, for example from a stock solution or the undiluted electrolyte, and mixing it intensively into the water to be treated. The calcium compound is added by preparing a working solution and mixing it intensively into the water to be treated, for example by producing lime milk from burnt or extinguished lime. The use of solid substances, for example by sprinkling salts into the water to be treated, is possible, but usually requires additional consumption. The carbon dioxide is added by Introduces carbon dioxide gas into the preferably alkaline solution. Simple gassing devices for containers or pipes are sufficient. Alternatively, instead of carbon dioxide gas, a soluble hydrogen carbonate or carbonate, preferably sodium hydrogen carbonate, can be dissolved or added to the water as a solid.
Bei allen Schritten ist die Kontrolle des pH-Wertes die maßgebende Größe. Für die Begasung mit CO2 liegt der optimale pH-Wert zwischen 10,8 und 11,2. Vor Abtrennung der gefällten Feststoffe soll der pH-Wert 8,7 nicht unterschritten werden. Dieses gilt auch bei einer stufenweisen, wechselnden Dosierung der Reagenzien.The control of the pH value is the decisive factor in all steps. For gassing with CO2, the optimal pH is between 10.8 and 11.2. Before separating the precipitated solids, the pH should not fall below 8.7. This also applies to a gradual, changing dosage of the reagents.
Das erfindungsgemäße Verfahren kann zum Klären von wäßrigen Flüs¬ sigkeiten mit feinverteilten anorganischen oder organischen syn¬ thetischen Stoffen, insbesondere vollsynthetischen Stoffen verwen¬ det werden. Wäßrige Dispersionen mit derartigen Stoffen werden mit Dispergiermittel stabilisiert. Dabei handelt es sich um wasserlös¬ liche Polymere als Schutzkolloide und Emulgatoren. Polymere sind Naturprodukte wie Alginate, Tragant, Agar-Agar, Dextrine und Stärke, modifizierte natürliche Polymere wie Carboxymethyl- cellulose, Hydroxyethylcellulose, Methylcellulose, Hydroxyethyl- stärke und synthetische Polymere wie Copolymerisate Styrol/Malein- säureanhydrid, Polymethacrylat, Polyvinylpyrrolidon, Polyvinyl- alkohol, teilweise verseiftes Polyvinylacetat, usw.. Emulgatoren sind insbesondere anionische Tenside wie Alkansulfonate und Fettalkoholethersulfate oder nichtionische Tenside wie Nonyl- phenoloxethylate.The process according to the invention can be used to clarify aqueous liquids with finely divided inorganic or organic synthetic substances, in particular fully synthetic substances. Aqueous dispersions with such substances are stabilized with dispersants. These are water-soluble polymers as protective colloids and emulsifiers. Polymers are natural products such as alginates, tragacanth, agar-agar, dextrins and starch, modified natural polymers such as carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, hydroxyethyl starch and synthetic polymers such as copolymers styrene / maleic anhydride, polymethacrylate, polyvinyl pyrrolidone, polyvinyl alcohol, partially saponified polyvinyl acetate, etc. Emulsifiers are, in particular, anionic surfactants such as alkanesulfonates and fatty alcohol ether sulfates or nonionic surfactants such as nonylphenol oxethylates.
Deshalb ist das Brechen derartig stabilisierter Dispersionen im Gegensatz zu Dispersionen aus natürlichen Stoffen besonders schwer, insbesondere dann, wenn die Schutzkolloide in einer Menge von ins¬ gesamt 20 bis 60 kg/m^ vorliegen. Es war daher überraschend, daß das erfindungsgemäße Verfahren nicht nur bei der bekannten Dünnsaft-Reinigung in der Zuckerproduktion brauchbar ist, sondern auch bei den Abwassern aus stabilisierten Dispersionen von synthe¬ tischen Verbindungen.Therefore, in contrast to dispersions made of natural substances, breaking such stabilized dispersions is particularly difficult, especially when the protective colloids are present in a total amount of 20 to 60 kg / m 2. It was therefore surprising that the method according to the invention is not only known Thin juice cleaning is useful in sugar production, but also for wastewater from stabilized dispersions of synthetic compounds.
Das erfindungsgemäße Ausflock-Verfahren eignet sich besonders zur Reinigung von Industrie-Abwasser. Diese Industrie-Abwasser sind ganz allgemein charakterisiert durch die Anwesenheit einer stabi¬ lisierten Emulsion oder Dispersion von anorganischen oder orga¬ nischen synthetischen Stoffen, die nicht allein durch die Verwen¬ dung von mehrwertigen Elektrolyten gereinigt werden können.The flocculation process according to the invention is particularly suitable for cleaning industrial wastewater. These industrial wastewater are generally characterized by the presence of a stabilized emulsion or dispersion of inorganic or organic synthetic substances, which cannot be purified solely by using polyvalent electrolytes.
Die Fällung mit Kalk und Kohlensäure bietet eine Reihe von Vor¬ teilen:Precipitation with lime and carbonic acid offers a number of advantages:
Beide Reagenzien sind preiswert und in großen Mengen verfügbar.Both reagents are inexpensive and available in large quantities.
Für den verlustfreien Eintrag von CO2 sind Apparate am Markt erhältlich.Devices for the loss-free entry of CO2 are available on the market.
Die Verwendung von Kohlendioxid vermeidet die erheblicheThe use of carbon dioxide avoids the significant
Aufsalzung des Abwassers.Salting of the wastewater.
Die Löslichkeit des Fällprodukts ist extrem niedrig.The solubility of the precipitate is extremely low.
Feststoff und Abwasser bleiben schwach alkalisch (pH 8,7 bisSolid and waste water remain weakly alkaline (pH 8.7 to
9).9).
Der Feststoff besitzt eine hohe Dichte und läßt sich schnell sedi entieren oder filtrieren. Da die Abtrennung des Feststoffs bestimmende Korngröße kann leicht durch Art und Dauer der Kohlendioxidzugabe beeinflußt werden.The solid has a high density and can be sedated or filtered quickly. Since the separation of the solid determines the grain size, it can easily be influenced by the type and duration of the addition of carbon dioxide.
Die erreichbare Trockensubstanz liegt über der von anderen Verfahren. ie Erfindung wird durch folgendes Beispiel näher erläutert: Beispiel :The achievable dry matter is above that of other processes. The invention is illustrated by the following example: For example:
Abwasser aus einem PVAc-Dispersionen herstellenden und verarbei¬ tenden Betrieb (Wasch- und Spülwasser) mit einem Trockensubstanz¬ gehalt von 28 g/1 (s 28 kg/m3).Waste water from a plant producing and processing PVAc dispersions (washing and rinsing water) with a dry matter content of 28 g / 1 (s 28 kg / m 3 ).
1. Koagulation der Dispersion durch1. Coagulation of the dispersion by
Zugabe von Eisen(III)chloridsulfat (41 %ige Lösung): 5,6 kg/m3 Addition of iron (III) chloride sulfate (41% solution): 5.6 kg / m 3
2. Kalkung durch2. Liming through
Zugabe von Kalk (30 %ige Kalkmilch) 40 kg/m3 Add lime (30% milk of lime) 40 kg / m 3
3. Neutralisation und Flockungsfällung mit Kohlensäure durch Einleiten von Kohlendioxid 9 kg/m3 3. Neutralization and flocculation with carbonic acid by introducing carbon dioxide 9 kg / m 3
4. Filtration4. Filtration
Kuchenmenge 60 kg/m3 Cake quantity 60 kg / m 3
Trockensubstanz 60 %Dry matter 60%
Das Filtrat war klar. Die Filtration des Feststoffes von der Flüs¬ sigkeit dauerte nur halb so lang wie bei einem herkömmlichen Rei¬ nigungsverfahren allein mit einem Elektrolyten und einer Kalkver¬ bindung. The filtrate was clear. The filtration of the solid from the liquid took only half as long as in a conventional cleaning process using only an electrolyte and a lime compound.

Claims

Patentansprüche Claims
1. Verfahren zum Ausflocken eines feinverteilten organischen oder anorganischen synthetischen Stoffes aus einer wäßrigen Flüs¬ sigkeit durch Zusatz1. Process for flocculating a finely divided organic or inorganic synthetic substance from an aqueous liquid by addition
1. eines mehrwertigen Elektrolyten,1. a polyvalent electrolyte,
2. einer Calcium-Verbindung und2. a calcium compound and
3. einer Kohlenstoff-Verbindung, die mit Calcium ein schwerlösliches Reaktionsprodukt ergibt.3. a carbon compound that gives a poorly soluble reaction product with calcium.
2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß man als mehrwertigen Elektrolyten eine polymere, kationische Verbindung zusetzt.2. The method according to claim 1, characterized in that a polymeric, cationic compound is added as the polyvalent electrolyte.
3. Verfahren nach Anspruch 1, gekennzeichnet durch gelöschten Kalk als Calcium-Verbindung.3. The method according to claim 1, characterized by slaked lime as a calcium compound.
4. Verfahren nach Anspruch 1, gekennzeichnet durch einen pH- Bereich von 8,7 bis 9.4. The method according to claim 1, characterized by a pH range from 8.7 to 9.
5. Verfahren nach mindestens einem der Ansprüche 1 bis 4, gekenn¬ zeichnet durch Kohlendioxid als Kohlenstoff-Verbindung.5. The method according to at least one of claims 1 to 4, gekenn¬ characterized by carbon dioxide as a carbon compound.
6. Verfahren nach mindestens einem der Ansprüche 1 bis 5, gekenn¬ zeichnet durch den wechselweisen Zusatz an Calcium-Verbindung und Kohlendioxid. ,6. The method according to at least one of claims 1 to 5, gekenn¬ characterized by the alternate addition of calcium compound and carbon dioxide. .
7. Verwendung der Verfahren nach mindestens einem der Ansprüche 1 bis 6 zur Reinigung von Industrieabwasser durch Abtrennung der ausgeflockten Feststoffe, insbesondere durch Filtration oder Sedimentation. 7. Use of the method according to at least one of claims 1 to 6 for the purification of industrial wastewater by separating the flocculated solids, in particular by filtration or sedimentation.
8. Verwendung nach Anspruch 7, dadurch gekennzeichnet, daß es sich um Abwasser von Dispersionen auf der Basis von Homo- und Copolymeren des Vinylacetats handelt.8. Use according to claim 7, characterized in that it is wastewater from dispersions based on homo- and copolymers of vinyl acetate.
9. Verwendung nach Anspruch 7, dadurch gekennzeichnet, daß es sich um Abwasser von Dispersionen handelt, die mit insgesamt 20 bis 60 kg/m3 Schutzkolloiden stabilisiert sind. 9. Use according to claim 7, characterized in that it is wastewater from dispersions which are stabilized with a total of 20 to 60 kg / m 3 protective colloids.
PCT/EP1992/002476 1991-11-07 1992-10-29 Flocculation process WO1993009064A1 (en)

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DE19914136616 DE4136616A1 (en) 1991-11-07 1991-11-07 flocculation
DEP4136616.6 1991-11-07

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EP0672624A1 (en) * 1994-02-21 1995-09-20 Ecc International Limited Treatment of waste water
US5618439A (en) * 1993-04-20 1997-04-08 Boliden Contech Ab Method for purifying industrial sewage water
FR3040387A1 (en) * 2015-08-25 2017-03-03 Sarp Ind METHOD FOR REGENERATING RINSING LIQUIDS

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FR2775682B1 (en) * 1998-03-09 2000-04-14 Carboxyque Francaise TREATMENT OF AQUEOUS EFFLUENTS BY CARBONIC ANHYDRIDE INJECTION
AP2014007840A0 (en) 2012-01-06 2014-07-31 Pureteq As Method and system for purification of produced water

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5618439A (en) * 1993-04-20 1997-04-08 Boliden Contech Ab Method for purifying industrial sewage water
EP0622338B1 (en) * 1993-04-20 1997-08-27 Boliden Contech Ab A method for purifying industrial sewage water
EP0672624A1 (en) * 1994-02-21 1995-09-20 Ecc International Limited Treatment of waste water
FR3040387A1 (en) * 2015-08-25 2017-03-03 Sarp Ind METHOD FOR REGENERATING RINSING LIQUIDS

Also Published As

Publication number Publication date
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DE4136616A1 (en) 1993-05-13

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