Classifications

• • 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
  • C02F1/54—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
  • C02F1/547—Tensides
• • 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
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F11/00—Treatment of sludge; Devices therefor
  • C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
  • C02F11/14—Treatment of sludge; Devices therefor by de-watering, drying or thickening with addition of chemical agents
  • C02F11/148—Combined use of inorganic and organic substances, being added in the same treatment step

Definitions

• the present invention relates to the use of new compositions for conditioning sludge prior to their dewatering operation.
• the object of the present invention is in particular to provide a compound which can be used effectively in the conditioning of sludges making it possible to increase their dryness, that is to say to increase the dry extracts obtained during the subsequent dewatering (filtration) operation. .
• the latter proposes, for the conditioning of sludge, the use of a composition, in particular of a solution, capable of being obtained by mixing ( reaction), in general with stirring, of at least one solution A of at least one anionic surfactant, the nonionic part of which has an HLB ("Hydrophilic / Lipophilic Balance") value of at most 10 with at least a solution B of at least one mineral cation of charge greater than or equal to 2, in a proportion greater than the stoichiometry.
• HLB Hydrophilic / Lipophilic Balance
• proportion greater than stoichiometry is meant that the mineral cation molar ratio of charge greater than or equal to 2 on anionic surfactant is greater than the charge ratio of the anionic surfactant to charge of said mineral cation.
• Any anionic surfactant has a nonionic part and an ionic polar part.
• the anionic surfactant of solution A is such that its nonionic part (which generally consists of a hydrocarbon chain of hydrophobic character and, optionally, of a polyalkoxylated chain of hydrophilic character , especially polyethoxylated) has a value
• HLB Hydrophiiie / Lipophilie
• This nonionic part (which corresponds to the nonionic surfactant from which said anionic surfactant can be prepared) may in particular have an HLB value of at most 8, for example at most 4.
• the ionic polar part of the anionic surfactant of solution A is usually a phosphate, phosphonate, carboxylate, sulfonate, sulfate or succinate of an alkali or alkaline earth metal. It is possible in particular to use an anionic surfactant chosen from alkylphosphates, alkylarylphosphates, etherphosphates, alkylsulfonates, alkylbenzenesulfonates, alkylsulfates, alkylarylsulfates, alkylethersulfates, alkylarylethersulfates or polyalkyloxyethoxyl) no, the nonionic part of which has an HLB value of at most 10, in particular at most 8, for example at most 4.
• said anionic surfactant is an alkali metal, preferably sodium, dodecyl sulfate.
• the mineral cation of solution B has a charge greater than or equal to 2.
• Said cation is preferably Fe 3+ or even more preferably Al 3+ .
• said mineral cation is present in solution B in general in the form of a soluble salt.
• soluble salt chlorides, nitrates, acetates can be used.
• a soluble salt is used which is free from the nitrogen element, which makes it possible to overcome any problems linked to its presence.
• a chloride is used.
• Solution B is preferably a solution of ferric chloride or, even more preferably, a solution of aluminum chloride.
• solution A of anionic surfactant for example in the case of alkali metal dodecyl sulfate, and solution B of mineral cation with a charge greater than or equal to 2, for example in the case of aluminum chloride , are implemented in such a way that the molar ratio (mineral cation of charge greater than or equal to 2) / (anionic surfactant) is between 1 and 20, in particular between 1, 5 and 10; solutions A and B are for example implemented in such a way that this molar ratio is between 2 and 5.
• the amount of anionic surfactant used is preferably at most 0.6 mole, in particular at most 0.4 mole, for example between 0.1 5 and 0.35 mole, per kg of reaction mixture (solutions A + B).
• the amount of mineral cation with a charge greater than or equal to 2 used is preferably between 0.2 and 0.9 mole, in particular between 0.25 and 0.8 mole, for example between 0.35 and 0, 65 mole, per kg of reaction mixture (solutions A + B).
• Solution A generally has an anionic surfactant content greater than its critical micellar concentration: it thus generally contains the anionic surfactant in the form of micelles.
• Solution B generally has an inorganic cation content (of charge greater than or equal to 2) lower than the solubility of the salt used.
• the pH of the anionic surfactant solution A is lower than the polymerization pH of said mineral cation: thus, preferably, this mineral cation does not polymerize during the preparation of the composition used according to the invention . It is desirable that the anionic surfactant is in dissolved form in solution A.
• the pH of the solution B of mineral cation with a charge greater than or equal to 2 is lower than the polymerization pH of said cation: this mineral cation is thus preferably used in non-polymerized form.
• solutions A and B to be mixed are found at a temperature between 10 and 75 ° C.
• the temperature of the anionic surfactant solution A is generally higher than its Kraft temperature.
• composition used in the present invention is generally prepared by adding solution A of anionic surfactant to solution B of an inorganic cation with a charge greater than or equal to 2. According to a preferred variant, on the one hand, this addition is performed slowly, and, on the other hand, solution A has a temperature between 10 and 30 ° C. According to another even more preferred variant, on the one hand, this addition is carried out quickly, and, on the other hand, solution A has a temperature of at least 40 ° C, for example between 40 and 75 ° C.
• composition used in the context of the invention is generally in the form of a solution.
• the preparation conditions are such that this solution is preferably homogeneous, in particular monophasic.
• the pH of the composition used in the invention is advantageously less than 2.
• the quantity of this composition used during the conditioning of a sludge is such that it generally corresponds between 1 and 3 times, preferably 2 times, the amount of theoretical cationic charge to neutralize the amount of anionic charge of the sludge to be treated; in other words, the quantity of composition used is generally such that it has an absolute cationicity generally equal to 1 to 3 times, preferably equal to 2 times, the anionicity of the sludge to be treated.
• An aqueous solution A of sodium dodecyl sulfate is prepared by introducing, with stirring, 1 1 2.5 g of sodium dodecyl sulfate in 937.5 g of water with a pH equal to 10.0, then adding 80 ml of hydrochloric acid 1 N to adjust the pH to 1.7; the solution is then heated to 60 ° C.
• a solution B of aluminum chloride is prepared by introducing, with stirring, 1.89 g of AICI 3 , 6H 2 0 in 225 g of water.
• Solution A heated to 60 ° C. is then quickly added to solution B with stirring.
• the molar ratio (Al 3 + ) / (sodium dodecyl sulfate) is equal to 2.
• the amount of sodium dodecyl sulfate used is 0.25 mol per kg of reaction mixture; the amount of aluminum used is 0.5 mol per kg of reaction mixture.
• An aqueous solution A of sodium dodecyl sulfate is prepared by introducing, with stirring, 1 1 2.5 g of sodium dodecyl sulfate in 937.5 g of water with a pH equal to 10.0, then adding 69 ml of hydrochloric acid 1 N to adjust the pH to 1.7; the solution is then heated to 60 ° C.
• a solution B of aluminum chloride is prepared by introducing, with stirring, 1.89 g of AICI 3 , 6H 2 0 in 225 g of water.
• Solution A heated to 60 ° C. is then quickly added to solution B with stirring.
• the molar ratio (Al 3 + ) / (sodium dodecyl sulfate) is equal to 2.
• the amount of sodium dodecyl sulfate used is 0.25 mol per kg of reaction mixture; the amount of aluminum used is 0.5 mol per kg of reaction mixture.
• An aqueous solution A of sodium dodecyl sulfate is prepared by introducing, with stirring, 380 g of sodium dodecyl sulfate in 500 g of water with a pH equal to 10.0; the pH of the mixture obtained is then adjusted to 1.5 ⁇ 0.2 by adding 1N hydrochloric acid; the mass of said mixture is then completed to
• a solution B of ferric chloride is prepared by introducing, with stirring, 357 g of FeCl 3 , 6H 2 0 into 643 g of water.
• solution A is added to solution B, in a 50/50 mass ratio.
• the amount of additive added to the sludge is such that it corresponds to twice the amount of theoretical cationic charge to neutralize the amount of anionic charge of the sludge to be treated.
• Each filtration is carried out according to the conditions of the experimental standard NF T 97-001 (1,979), points 4 and 5, using a synthetic textile filter cloth in place of the filter paper and not using a support cloth.
• the filter cake is recovered after exerting a pressure such that the differential pressure between that applied and the atmospheric pressure is 0 bar for 60 seconds, then 2 bar for 10 minutes and finally 10 bar for 5 minutes.
• the dryness is equal to the ratio M2 / M1 (expressed in%), in which M2 is the mass of the filter cake after drying in the oven at 105 ° C for 1 hour, until constant mass,
• MMS solid volatile matter

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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)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Detergent Compositions (AREA)
• Treatment Of Sludge (AREA)

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• 1999
  • 1999-05-28 FR FR9907299A patent/FR2794118B1/fr not_active Expired - Fee Related
• 2000
  • 2000-05-29 WO PCT/FR2000/001473 patent/WO2000073219A1/fr active Search and Examination
  • 2000-05-29 AU AU52279/00A patent/AU5227900A/en not_active Abandoned
  • 2000-05-29 EP EP00936973A patent/EP1196356A1/de not_active Withdrawn

Non-Patent Citations (1)

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