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
  • C02F1/5236—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
• • 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
  • C02F1/5272—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using specific organic precipitants
• • 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
  • C02F1/001—Processes for the treatment of water whereby the filtration technique is of importance
• • 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
  • C02F1/24—Treatment of water, waste water, or sewage by flotation
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2209/00—Controlling or monitoring parameters in water treatment
  • C02F2209/09—Viscosity
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2209/00—Controlling or monitoring parameters in water treatment
  • C02F2209/11—Turbidity

Definitions

• the invention relates to a water purification process, in particular a method comprising a coagulation-flocculation step using, together with a metal salt, a liquid cationic solubilized particular starch composition.
• aqueous solution of ground water or surface water that you will treat, such as water from a lake or watercourse.
• This aqueous solution always comprises a greater or lesser amount of suspended particles which it is necessary to eliminate.
• the finer particles in suspension can also be removed by separating them from the aqueous solution to be treated, for example by decantation or by flotation.
• Decantation consists of allowing the solution to settle in a settling tank, also called a "settling tank", so that the suspended particles are deposited at the bottom of this tank.
• the purified water is thus recovered by overflow.
• Flotation has the principle of mixing in a float the aqueous solution with air, in order to recover the particles on the surface.
• the water thus treated is recovered at the bottom of the float.
• the aqueous solution generally comprises fine particles whose separation is particularly difficult, in particular colloidal particles of very small size, generally ranging from 1 nm to 1 ⁇ .
• a coagulation-flocculation step is first carried out. This step consists in the agglomeration of the particles in suspension: these larger agglomerated particles are then separated more easily and more quickly by the separation treatments mentioned above.
• coagulants and flocculating agents are used alone or in mixture. These agents may be chosen from iron or aluminum salts, anionic or cationic polyacrylamides and nonionic, anionic or cationic starches.
• the coagulating agent and the flocculating agent are mixed in two distinct stages with the aqueous solution to be treated in a tank, called coagulation-flocculation tank in the present application.
• This tank is generally composed of a first pool called “coagulation basin” and a second basin called “flocculation basin”, in which are introduced respectively coagulant and flocculant.
• COD Chemical Oxygen Demand
• turbidity level of the aqueous solution, or turbidity is measured by a nephelometer (also called turbidimeter) and is measured in Nephelometric Turbidity Unit (NTU or NTU for Nephelometric Turbidity Unit).
• NTU Nephelometric Turbidity Unit
• Another means is also to measure the absorbance of the aqueous solution treated at a given wavelength.
• the water thus purified is generally subjected to a "filtration step” of passing the water through one or more filters to remove some residual pollutants. It is also possible to carry out a disinfection step, consisting of adding an agent or using a treatment capable of eliminating the bacteria present in this water. These latter treatments are particularly useful in a potabilization process.
• Water treatment processes are generally continuous processes.
• a filtration step takes place to make the drinking water, the last particles remaining in suspension are removed from the aqueous solution by passing through the filters.
• the particles accumulate inside the filters and they clog up.
• There is then a "loss of charge” that is to say a loss of flow of filtered water at constant pressure applied to the filter.
• the aqueous solution to which this filtration step is subjected must have a low turbidity, generally less than 1.5 NTU, preferably less than 1 NTU.
• cationic starch-based agents Processes for treating drinking water using cationic starch-based agents have already been described. Indeed, these cationic starches have the advantage of being made from renewable plant resources and being available in large volumes.
• WO 200196403 A1 describes, for the treatment of industrial process water, the use of a cationic starch in combination with a flocculant of cationic polyacrylamide type.
• a coagulation-flocculation step using a mixture of cationic polyacrylamide and a cationic starch is studied in Example 10. The tests therein show that, in combination with a cationic polyacrylamide, a starch Cationic fluidized and therefore low viscosity has a greater efficiency than a non-fluidized cationic starch.
• this process can be performed using a fast treatment time, using a small amount of chemicals, and this without modifying the facilities conventionally used for these treatments. It must be able to significantly reduce the turbidity of the treated water.
• a liquid composition of cationic starch having specific characteristics when used in a coagulation-flocculation step together with a ferric salt and / or an aluminum salt, to reduce particularly interestingly the turbidity of the aqueous solution to be treated in comparison with the cationic starches conventionally used in this field.
• This particular starch must be, when it is introduced into the water to be treated, in the form solubilized in a liquid composition.
• This composition may be used, with a metal salt, in any type of process for obtaining a drinking water comprising a coagulation-flocculation step.
• the subject of the invention is a process for the potabilization of an aqueous solution having suspended solids, containing a coagulation-flocculation step, characterized in that the said step comprises:
• steps a) and b) being carried out in any order and can be done separately, simultaneously or via a liquid composition comprising both the solubilized cationic starch and the metal salt, said steps a) and b ) being followed:
• said liquid composition comprising cationic starch having a viscosity, measured according to an A test, greater than 1000 mPa.s, this test A consisting in adjusting the dry mass of the liquid composition to 10% and then measuring the Brookfield viscosity at 25 ° C. C of the resulting composition.
• Test A used to measure the viscosity of said liquid composition is applicable regardless of the form of presentation thereof, liquid or pasty.
• the amounts of cationic starch and metal salt are expressed in dry mass in the following application.
• the Applicant has found that, when used in a coagulation-flocculation step in combination with a metal salt, a liquid composition having a high viscosity, ie greater than 1000 mPa.s, for a starch concentration. cationic relative to 10% of the total mass of the composition, allowed to obtain an exceptional reduction in the turbidity of a solution with suspended solids.
• the delay between steps a) and b) is less than 120 seconds, for example less than 90 seconds, advantageously less than 60 seconds.
• steps a) and b) are performed simultaneously.
• these two steps are carried out simultaneously by the addition of a liquid composition comprising both the cationic starch and the metal salt, which simplifies the process.
• the cationic starch can be obtained from pea starch, wheat, corn or potato starch.
• the metal salt is a sulfate, a polysulfate, a chloride, a polychloride or a polychlorosulphate.
• the metal salt is chosen from polyaluminium chloride and ferric chloride.
• step b) It may be added during step b) in the form of a liquid solution, for example having a concentration ranging from 0.01 to 60 g / l.
• the amounts of metal salt are the total amounts of these various metal salts.
• the process of the invention can be carried out with a total amount of cationic starch and metal salt in the aqueous solution ranging from 4 to 500 ppm.
• This amount is adapted to the turbidity of the initial water and may advantageously be from 5 to 20 ppm, preferably from 5 to 10 ppm.
• the mass ratio cationic starch / metal salt can range from 15/85 to 70/30, for example from 15/85 to 60/40, advantageously from 15/85 to 55/45. preferably 20/80 to 45/55.
• the mass ratio cationic starch / metal salt may range from 30/70 to 60/40.
• the Applicant has found that the coagulation-flocculation step is particularly effective when these coagulants are introduced in the ratios above.
• the cationic starch may have a degree of cationic substitution greater than or equal to 0.03, advantageously ranging from 0.035 to 0.2.
• the cationic starch liquid composition introduced in step a) advantageously has a cationic starch concentration ranging from 0.01 to 50 g / l.
• the liquid of the composition may be any solvent of the cationic starch and is preferably water.
• the stirring step c) can be carried out in the presence of an additional treatment agent which can be selected from algae, activated carbons and potassium permanganate.
• the treatment agent is preferably activated carbon or potassium permanganate.
• the duration of the stirring step c) may be greater than or equal to 1.5 minutes or more, preferably ranging from 2 to 30 minutes, most preferably ranging from 2.5 to 5 minutes.
• the separation step d) may be a decantation step.
• This decantation step preferably has a duration ranging from 0.25 to 1000 minutes, preferably from 0.33 to 120 minutes, most preferably from 0.5 to 12 minutes, for example from 1 to 5 minutes.
• the flocs can be ballasted, for example using micro sand.
• Another advantage of the invention is therefore that the coagulation-flocculation step can thus be performed in a very short time.
• the process can be continuous or discontinuous.
• the times of steps c) and d) are thus respectively the mean residence time of the aqueous solution to be treated in the coagulation-flocculation tank and in the settling tank.
• the potabilization process according to the invention is particularly well suited when it comprises, after the coagulation-flocculation step, a step of filtering the purified water.
• the aqueous solution comprising suspended solids to be treated may have a turbidity less than or equal to 1000 NTU, advantageously ranging from 2 to 300 NTU, preferably ranging from 2.5 to 150 NTU, for example ranging from 3 to 100 NTU.
• This aqueous solution may be surface water, for example river or river lake water or groundwater.
• the process is very advantageous for removing particles in suspension in the aqueous solution having a size ranging from 0.001 to 500 ⁇ m, in particular those ranging from 0.001 to 1 ⁇ m.
• the turbidity of the purified aqueous solution thus obtained at the end of step e) has a low turbidity, for example less than or equal to 1.5 NTU, preferably less than 1 NTU.
• the turbidity reduction may be greater than 98%, advantageously greater than 98.5%, most preferably greater than 99%.
• the method according to the invention makes it possible to greatly reduce turbidity, which is very advantageous in a process of potabilization.
• Turbidity can be measured using a WTW Turb 555IR device sold by WTW.
• the liquid composition useful for the invention has a viscosity greater than 1000 mPa.s according to the test A described above. As will be discussed below, this particular viscosity is directly related to the cationic starch used and the process for preparing the composition.
• the viscosity of the composition comprising it after solubilization depends on three main characteristics, in descending order of importance: its molecular weight, its branching rate and its degree of cationicity. These characteristics are readily selected by those skilled in the art by choosing the botanical source of the native starch and the conditions of preparation of this cationic starch.
• the cationic starch used in the context of the invention can be obtained from any type of native starch of natural or hybrid origin, including starch derived from plant organisms having undergone genetic mutations or manipulations.
• Said starches may in particular be derived from potato, high amylopectin potato (waxy potato), wheat, high amylopectin wheat (waxy wheat), corn, high grade corn amylopectin (waxy corn), high amylose maize, rice, peas, barley or cassava, cuts or fractions thereof, and any mixtures of any two or more of the products above.
• the selection of this native starch has, for example, an influence on the final molecular weight as well as on its branching rate, related to the content of amylose and amylopectin.
• the cationization reaction can be carried out according to one of the methods well known to those skilled in the art, using cationic reagents as described for example in "Starch Chemistry and Technology” - Vol. He - Chapter XVI - R. L. WHISTLER and E. F. PASCHALL - Academy Press (1967).
• the starch is introduced into a reactor in the presence of these reagents.
• the starch used during the cationization reaction is in a granular form.
• the reaction may be conducted in the milk phase, wherein the granular starch suspended in a solvent is cationized using the conditions of temperature, time and catalysis well known to those skilled in the art.
• the starch thus cationized can be recovered by filtration, this cationic starch can then be washed and then dried.
• the reaction can be carried out in the dry phase, that is to say in the presence of quantities of water added to the starch considered as low, for example in amounts of water of less than 20%.
• the starch mass introduced for the cationization reaction preferably less than 10%.
• the cationization reaction is carried out with nitrogen-containing reagents based on tertiary amines or quaternary ammonium salts.
• nitrogen-containing reagents based on tertiary amines or quaternary ammonium salts.
• these reagents it is preferred to use 2-dialkylaminochlorethane hydrochlorides such as 2-diethylaminochloroethane hydrochloride or glycidyltrimethylammonium halides and their halohydrins, such as N- (3-chloro-2-hydroxypropyl) trimethylammonium chloride.
• This latter reagent being preferred.
• This reaction is carried out alkaline medium, at a pH greater than 8 or 10, the pH can be adjusted for example by sodium hydroxide.
• the levels of reagent used are chosen such that the resulting cationic starches have the degree of substitution (DS) of desired cationicity, the DS being the average number of OH groups included on the anhydroglucose of the starch which have been substituted with a cationic group.
• DS degree of substitution
• the cationic starch may be soluble at room temperature in water.
• soluble at room temperature is meant according to the invention that, when the cationic starch is introduced at 10% by weight of the water at 20 ° and is stirred for 1 hour, the starch solution thus obtained has a Brookfield viscosity greater than 1 000 mPa.s.
• the starch soluble at room temperature in water is a cationic granular starch having a degree of substitution (DS) greater than or equal to 0.10.
• it is a pregelatinized cationic starch. This pregelatinization treatment of cationic starch can be carried out on a drying drum.
• the liquid composition is generally an aqueous composition, which may comprise mainly water and possibly small amounts of water-miscible organic solvents, such as alcohols such as methanol and ethanol, for example in amounts of solvent. less than 10% by weight of all the solvents.
• the cationic starch in the solvent can be rendered soluble by a cooking step.
• a cooking step we realize generally this cooking in water by suspending cationic starch and thus forming a starch milk.
• a "soft" cooking of the starch milk is carried out.
• soft cooking is meant cooking using a low temperature and / or a short duration, the skilled person adapting the temperature and time to obtain the viscosity useful in the manufacture of the solution.
• the firing temperature is, for example, in the temperature range of 40 to 95%, preferably 60 to 90%.
• the cooking time can range from 5 minutes to 60 minutes.
• the quantity of cationic starch in this milk may be in the range of between 10 and 30%, for example between 20 and 30%.
• said composition is prepared by using a soluble cationic starch at ambient temperature and by putting it in solution in water, preferably with stirring.
• This variant is advantageous because the starch is thus easily solubilized in the liquid composition without cooking.
• the composition useful to the invention can thus easily be implemented on the site carrying out the treatment process.
• the cationic starch is not cooked during the preparation of the composition, the starch is not thermally degraded during its solubilization, which makes it possible to obtain a viscosity composition greater than that obtained at from the same starch having undergone a cooking step in the solvent.
• a liquid composition can be used to carry out the process according to the invention.
• This composition comprises a solubilized cationic starch and one or more metal salts chosen from ferric salts and aluminum salts, and its viscosity, measured according to test A, is greater than 1000 mPa.s.
• the viscosity of the liquid composition comprising the cationic starch, measured according to test A, is preferably between 10,000 and 100,000 mPa.s.
• the metal salt is an aluminum salt.
• the composition advantageously has a mass ratio cationic starch / metal salt ranging from 15/85 to 70/30, preferably from 25/75 to 45/55.
• the pH of the composition according to the invention is between 3 and 7.
• a cationic starch liquid composition containing preservative is used.
• biocidal agent which may be chosen from phthalates, for example one of those marketed by Rohm & Haas under the trademark VINYZENE TM.
• these biocidal agents may constitute unwanted constituents for the treatment of a water and particularly for the production of water. drinking water.
• a preservative-free cationic starch solution is prepared within less than twenty-four hours before the addition step a) from a cationic starch in solid form, by example in the form of a powder.
• the composition useful in the invention has a Brookfield viscosity greater than 1000 mPa.s under the conditions of test A.
• the measurement of the viscosity, achieved by a Brookfield ® brand, is well known to those skilled in the art.
• there are different modules for measuring this viscosity and each module is suitable for a given viscosity range. It suffices to choose the module adapted to the viscosity of the composition to be measured.
• test A can be carried out using module RV2 at 20 rpm for a viscosity greater than 1000 mPa.s and less than or equal to 2000 mPa.s, the RV5 module at 20 rpm for a viscosity greater than 2000 mPa.s and less than or equal to 20000 mPa.s, the RV7 module at 20 rpm for a viscosity greater than 20000 mPa.s and less than or equal to 200000 mPas.s and the RV7 module at 2 rpm for a viscosity greater than 200000 mPa.s.
• composition comprising the cationic starch may further comprise additional constituents, such as metal salts or also biocidal agents already described.
• additional constituents such as metal salts or also biocidal agents already described.
• the solids content of the composition useful for the invention may consist exclusively or almost exclusively of at least one cationic starch but may also contain one or more other components such as, for example, a biocidal agent or other materials such as a metal salt previously described.
• the metal salt is advantageously polyaluminium chloride or ferric chloride.
• ferric chloride it is preferred that the cationic starch / metal salt ratio be 25/75 to 50/50, or even 30/70 to 40/60.
• polyaluminium chloride it is preferred that the cationic starch / metal salt ratio be 20/80 to 45/55, or even 25/75 to 35/65.
• coagulants may be used in the process, the latter may be carried out without any additional coagulant, especially without polyacrylamide and without clay.
• the coagulation-flocculation step can be carried out in a conventional manner.
• the particles are coagulated to form the flocs in a coagulation-flocculation tank.
• This tank may comprise a first pool called “coagulation basin” and a second pool called “flocculation basin", where the stirring speed is greater in the first than in the second.
• the starch composition and the metal salt are introduced into the coagulation basin.
• the aqueous solution to be treated is introduced into said vessel via a pump, which thus makes it possible to adjust the feed rate.
• the duration of the flocculation coagulation step then depends on this flow rate and the volume of the tanks used.
• the salt and starch useful in the invention may be mixed with the aqueous solution to be treated either before the introduction of this solution into the coagulation-flocculation tank, or directly into the tank by a second inlet provided for this purpose. .
• the duration of this coagulation-flocculation step depends directly on the volume of the tank and the flow rate chosen.
• the water to be treated may optionally undergo pretreatment adjustment of its pH.
• the pH of the aqueous solution comprising suspended solids ranges from 6 to 8.5.
• step d the formed flocs are decanted.
• this separation step is carried out by decantation, it is also possible to introduce into the coagulation-flocculation tank an agent capable of ballasting formed flocs, such as micrometric sand. These weighted flocs are transferred with the aqueous solution into the decanter, which makes it possible to improve the separation rate in the subsequent decantation stage.
• an agent capable of ballasting formed flocs such as micrometric sand.
• the decanter may be a static settler or a lamellar clarifier.
• the decanter can be equipped with bottom wiper for better capture of sludge.
• the static decanter is the most conventional decanter: it consists of a single tank in which the coagulated particles are deposited at the bottom of the tank to form sludge and recovering the purified water having undergone decantation by overflow.
• the lamellar decanters also make it possible to accelerate the decantation of the coagulated particles in comparison with the static decanters.
• This may be for example a filtration step.
• the coagulation-flocculation step used in the process according to the invention is then particularly advantageous.
• This water filtration step may be a microfiltration, ultrafiltration or nanofiltration step.
• filters such as filters comprising sand, anthracite or even activated carbons are used.
• membranes of organic polymers in particular polypropylene, polyacrylamide or polysulfone.
• a drinking water is obtained, the turbidity of which is advantageously less than 1 NTU.
• FeCl 3 ferric chloride in solution.
• PAM cationic polyacrylamide emulsion Flopam ® DW 2160.
• A cationic starch solution whose Brookfield viscosity is, according to test A, 1 1000 mPa.s.
• This solution “A” is obtained from a cationic starch (potato base) comprising 1.2% nitrogen (expressed in dry weight / sec).
• This starch is soluble in water at 20 ° C.
• the solution is prepared at 1% starch with stirring at room temperature for one hour.
• the cationic starch solution is the best coagulant at a dose of 10 mg / l.
• turbidity is less than 1 NTU, more than 99% reduction.
• the Lys water (initial turbidity: 3 NTU) is tested in Jar-Test, either with an Aqualenc ® brand of aluminum polychlorosulphate solution, or with a salt solution and solution A in a metal salt mass ratio.
• cationic starch equal to 3: 2.
• the total dose of salt used alone, or of salt and starch used together, is fixed at 10 mg per liter of water of the Lily.
• the coagulation-flocculation step is carried out in the same manner as in Example 1, except that the test is done in the absence of sand. Turbidity is measured at different settling times and the results obtained are listed in Table 2. Table 2
• the water treated jointly with salt and starch has a turbidity of less than 1 NTU after less than 3 minutes of settling, compared with 20 to 30 minutes with the salt alone.
• C cationic starch solution whose Brookfield viscosity is, according to test A, 86000 mPa.s. This solution “C” is obtained from a cationic starch (potato base) comprising 0.3% nitrogen (expressed in dry weight / sec). The solution is prepared by baking a 95% solution for 15 minutes.
• “1” (comparative): cationic starch solution whose Brookfield viscosity is, according to test A, 2 mPa.s. This solution “1” is obtained from a cationic starch (potato base) comprising 0.3% nitrogen (expressed in dry weight / sec). The solution is prepared with stirring at room temperature for one hour.
• “2” (Comparative): Cationic starch solution whose Brookfield viscosity is, according to test A, 600 mPa.s. This "2” solution is obtained from a cationic starch (potato base), which has undergone a fluidification treatment, comprising 1.2% nitrogen (expressed in dry weight / sec). The solution is prepared at 1% starch.
• "3” (comparative): Potato starch solution, nonionic, whose Brookfield viscosity is, according to test A, 200000 mPa.s. The solution is prepared by cooking the starch in water at 95 ° C for 15 minutes.
• starch solutions are tested alone or together with a solution of ferric chloride, in a weight ratio salt: starch equal to 3: 2.
• the total dose of starch used alone, or salt and starch used together, is set at 10mg per liter of water from the Lily.
• the test protocol is the same as that of Example 1 and the results obtained are listed in Table 3. Table 3
• Example 4 Determination of the Optimum Coagulant Dosage Based on Cationic Starch and Metal Salt
• the ferric chloride and the starch solution A (ratio of salt to starch of 3: 2) are tested together in Jar Test at different doses according to test protocol of Example 1.
• the mixture is effective from 6 mg / L to exceed 99% turbidity reduction.
• Example 1 The ferric chloride and starch solution A of Example 1 are tested together in Jar Test using different weight ratios of cationic starch / ferric chloride, for a total dosage of 10 mg / l.
• the test protocol is the same as that of Example 1.
• Figure 1 also shows the evolution of the turbidity as a function of the mass quantity of starch relative to the total amount of starch and metal salt.
• PAC1 is a polychlorosulfate of aluminum in solution. It is mixed with the cationic starch A. Jar Test tests are carried out at different ratios of cationic starch / aluminum salt, for a total dosage of 10 mg / l. The test protocol is the same as that of Example 1. The results are reported in Table 6.
• PAC2 is an aluminum polychloride solution. It is mixed with the cationic starch A. Jar Test tests are carried out at different ratios of cationic starch / aluminum salt, for a total dosage of 10 mg / l. The test protocol is the same as that of Example 1. The results are reported in Table 7. Table 7
• PAC3 is an aluminum sulphate solution. It is mixed with the cationic starch A. Jar Test tests are carried out at different ratios of cationic starch / aluminum salt, for a total dosage of 10 mg / l. The test protocol is the same as that of Example 1. The results are reported in Table 8.
• Cationic starch solutions comprising 1.2% nitrogen (expressed as dry weight / sec) are obtained from waxy corn, high amylose corn, protein peas and potatoes.
• Starch solutions used "4" cationic starch solution based on waxy maize, whose Brookfield viscosity is, according to test A, 1240 mPa.s.
• the water to be treated is river water taken from the lily. It is withdrawn from a 500L tank by a pump and is directed to a flow regulator.
• the flow meter is calibrated from 200L / h to 600L / h, at its output are the junctions that allow the injection of reagents.
• the injection of two reagents separately and at different flow rates is possible thanks to two small pumps connected to flow meters.
• Water and the mixture then arrive in the coagulation-flocculation tank, a beveled helix provides the stirring necessary for mixing the reagents.
• the water must then provide a discharge before arriving in a lamellar clarifier equipped with blades inclined at 45 °. Once the decanter is completely filled, the clarified water flows through a spillway and flows to a sink where it can be recovered for analysis.

Landscapes

• 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)
• Separation Of Suspended Particles By Flocculating Agents (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=46724490

Family Applications (1)

Country Status (6)

Families Citing this family (3)

Family Cites Families (13)

• 2011
  • 2011-07-22 FR FR1156702A patent/FR2978138B1/fr not_active Expired - Fee Related
• 2012
  • 2012-07-19 WO PCT/FR2012/051714 patent/WO2013014373A1/fr active Application Filing
  • 2012-07-19 EP EP12750424.9A patent/EP2734477A1/fr not_active Withdrawn
  • 2012-07-19 JP JP2014520706A patent/JP6008963B2/ja not_active Expired - Fee Related
  • 2012-07-19 US US14/234,238 patent/US20140197112A1/en not_active Abandoned
  • 2012-07-19 CN CN201280036121.0A patent/CN103717538B/zh not_active Expired - Fee Related

Non-Patent Citations (2)

Also Published As

Similar Documents

Legal Events