Water Treatment Division Incrustation Calcium carbonate, Magnesium carbonate, Calcium phosphate, Magnesium phosphate Barium or Calcium phosphate Calcium

  • View
    227

  • Download
    0

Embed Size (px)

Text of Water Treatment Division Incrustation Calcium carbonate, Magnesium carbonate, Calcium phosphate,...

  • Slide 1
  • Water Treatment Division Incrustation Calcium carbonate, Magnesium carbonate, Calcium phosphate, Magnesium phosphate Barium or Calcium phosphate Calcium fluoride Inorganic Silica Clays Aluminium Iron Manganese Organic Hydrocarbon Humic acids and fulvics Cationic Polielectrolite Biological Bacteria Fungus and yeast Polymer extracellular Disinfection or Bacteriostatic Active carbon absorption Antiscalant or Water softener Different previous filters Prevention or process delay Membranes, Getting dirty and obturation Demineralisers. Critical issue: contamination of membranes Pretreatments
  • Slide 2
  • Water Treatment Division Demineralisers. Critical issue: contamination of membranes The membranes are contaminated by several causes: Pretreatments Iron Chemical oxidation damage Excess pressure damage Collodial Material Compaction Biological Pollution Scaling by silica Biological Pollution
  • Slide 3
  • Water Treatment Division Chlorine remover Chlorine changes the membrane properties, allowing the salts to pass through the membranes easily, therefore chlorine must be removed before the RO treatment. The filtering material is coconut shell carbon, with a particle size distribution of 1,2-2,5 mm. Chlorine with carbon leads to a chemical reaction producing CO2 (carbon dioxide) and chloride, both dont damage the membrane. At the backwash stage, the particles settled in the filtering material are removed, and the carbon layer is rearranged (since the water goes through it) compressing the material and creating preferential channels that decreases the surface contact area between water and carbon. The active carbon must be replaced within 12-24 months. In addition to the consumption due to the chlorine removal reaction, the continued water flow with salts will lead to a decreased contact area due to the formation of scales on the carbon surface, delaying the chlorine removal process. Pretreatments Demineralisers. Pretreatments to remove Chlorine
  • Slide 4
  • Water Treatment Division Iron Demineralisers. Examples of contamination of the membranes Pretreatments
  • Slide 5
  • Water Treatment Division Iron remover The iron in water is usually found as Fe(II), highly soluble and not capable of being filtered. Iron, as Fe(II), is not a problem for the membrane task, nevertheless, after its oxidation (due to the oxygen contact, or after being chlorinated) changes to Fe(III) form that is a solid in suspension, it will plug the mesh spacer and the membrane will get dirty. The iron removal treatment lies in transforming the Fe(II) into Fe(III) form and its filtration. When Fe(II) has contact with the BIRM (manganese dioxide) it becomes oxidized, turning into Fe(III). Under this form the iron is not soluble, forming a granulated that can be sieved. In order to make this possible, the water must have a pH between 7 and 8,5, in addition to an oxygen concentration higher than 15% in relation to the iron or manganese concentration. We should take into account these premises at the start up stage, so if they are not fulfilled, it will be compulsory to check with our Central SAT. Pretreatments Demineraliser. Pretreatment to remove Iron
  • Slide 6
  • Water Treatment Division Solids in suspension Demineralisers. Examples of contamination of the membranes Pretreatments
  • Slide 7
  • Water Treatment Division Silex Filter Anthracite Solids in suspension. The solid presents a low inertia in its capacity of flotation/decantation, remaining suspended. It is normal not to distinguish the particles individually if their sizes are about the micrometer magnitude. The smallest particles (0,2-1 microns) are named as colloidal particles or colloids. It is needed to eliminate the solids in suspension, which plugged the mesh spacer. The silex is silica sand, similar to beach sand, but with a particle size distribution of 0,7-1,3 mm. The anthracite is a heavy mineral carbon, with a particle size of 1,2-2,5 mm. We take materials with different densities in order to increase the filtration capacity and its quality. The backwash is used as cleaning method, causing a mechanical rub. This rub releases and removes the filtered particles. The three materials, contained in the filter, are mixed after the backwash, coming apart again in the right order due to the density difference, just as it appears in the drawing. Pretreatments Demineraliser. Pretreatments to remove solids in suspension
  • Slide 8
  • Water Treatment Division Organic material Demineralisers. Examples of contamination of the membranes Pretreatments
  • Slide 9
  • Water Treatment Division Organic Material filter Organic material: All substance or molecule containing carbon (except carbonates). The carbon is in any molecule that belongs or was a part of a living creature. The organic material plugs the membrane, blocking it, and therefore decreasing its efficiency. The filtering material has the same characteristics as in the chlorine remover. The organic material, in contact with the carbon, sticks to the granulate due to molecular attraction forces. We have to take into account that both the organic material filter and the chlorine remover, are units that enhance the bacterium growth, because the carbon granulates offer a wide contact surface with the water due to its spongy form, therefore we should control the likely bacteriological contamination. If we have chlorine and organic material in the same water, IT WILL NOT BE NECESSARY to install a chlorine remover and an organic material filter, just placing the organic material filter will be enough (not the chlorine remover). Pretreatments Demineraliser. Pretreatments to remove the Organic Material
  • Slide 10
  • Water Treatment Division Biofilm Demineralisers. Examples of contamination of the membranes Pretreatments
  • Slide 11
  • Water Treatment Division Bisulfite The product is sodium bisulfite. The solution to inject is prepared at a maximum concentration of 10 g/l. It is dosed diluted in water, and after a period of 3-4 weeks, the content of the feeder drum must be renewed, even if the volume prepared is not yet finished, therefore the quantity of product to be prepared must be calculated. The control of the dosage pump is included in the electric panel of the demineraliser, in this way it will be dosed automatically in the water flow, before the demineraliser inlet. The microorganisms (bacterium) can survive inside the water pipes of the equipments, excreting a jelly film (biofilm) that can block the membranes. To avoid this problem, we have two methods available, both exclusive among them. Demineraliser. Pretreatments to remove the Biofilm Pretreatments
  • Slide 12
  • Water Treatment Division Biocide It is an organo-bromine compound (Genesol-30) with a wide bactericidal range (aerobic & anaerobic), suitable for all kind of membranes. It is acid and causes a partial dilution and the drag of the biofilm that could be settled in the membrane. A 400 ppm concentration must be added for 20-30 minutes once a week. The dosage is done by the automatic program, starting the pump after one week and there is water demand. The product is corrosive and is NOT suitable for food applications. Pretreatments Demineraliser. Pretreatments to remove the Biofilm
  • Slide 13
  • Water Treatment Division Biocide (Mod. 4069200)Bisulfite (Mod. 4044000) Consumible: Product available in 5 l drum, more expensive (Mod. 52418 228 ) Consumible: Product available in 25 l drum (Mod. 5241700 53 ) Cost of optionals: Cheaper optional doser: pump, support to the demineraliser or wall mounted and level sensor for the drum (Mod. 4069200 425) Cost of optionals: More expensive optional doser: pump, support, dilution deposit and level sensor for the drum (Mod. 4044000 460 ) Preparation: No need for preparation before the dosage, the product is used pure. PreparationTo prepare 100 litres of dilution following the start up tables, mixing the product and demineralised or tap water.: Dosage: It is dosed automatically for 20 minutes once a week, meanwhile the equipment is working. The repercussion in the quality of the demineralised water is insignificant. Dosage: It is dosed simultaneously with the antiscalant, this means, always that the equipment is producing demineralised water. It has not effect at all in the demineralised water quality. Application Range It is effective for all kind of aerobic and anaerobic bacteria, killing them. It is not dosed continuously because the product, in a long-term, causing a damage in the membranes. Application Range: It removes the oxygen from water and avoids the growth of the aerobic bacteria, which are the most common. Room requirements. Only the size of the 5 litres drum and the doser pump, easy to mount in a cabinet. Room requirements. It requires a 120 litres tank, included in the optional, besides the doser pump. Maintenance. To prime the pump after every drum change. The primed can be avoided if the content of a new drum is flowed into the drum just finished. Maintenance. If the product has not been consumed in 3-4 weeks we have to renew it, emptied completely and filling it up with the mixture required. Biocide vs Bisulfite Pretreatments
  • Slide 14
  • Water Treatment Division Lime Demineralisers. Examples of contamination of the membranes Pretreatments
  • Slide 15
  • Water Treatment Division Crystal of Calcium Carbonate (lime) Pretreatmentss
  • Slide 16
  • Water Treatment Division Scalant process. How are the crystals formed?. IONES IONPROTONUCLEUSNUCLEUS CRYSTALS ARR