Pretreatments Demineralisers Critical issue contamination of membranes Membranes

Pretreatments Demineralisers. Critical issue: contamination of membranes Membranes, Getting dirty and obturation Biological Organic Inorganic Incrustation Bacteria Hydrocarbon Silica Calcium carbonate, Fungus and yeast Humic acids and fulvics Clays Magnesium carbonate, Aluminium Calcium phosphate, Iron Magnesium phosphate Manganese Barium or Calcium phosphate Polymer extracellular Cationic Polielectrolite Calcium fluoride Disinfection or Bacteriostatic Active carbon absorption Different previous filters Antiscalant or Water softener Prevention or process delay Water Treatment Division

Pretreatments Demineralisers. Critical issue: contamination of membranes The membranes are contaminated by several causes: Collodial Material Iron Compaction Chemical oxidation damage Biological Pollution Scaling by silica Biological Pollution Excess pressure damage Water Treatment Division

Pretreatments Demineralisers. Pretreatments to remove 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 CO 2 (carbon dioxide) and chloride, both don’t 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. Water Treatment Division

Pretreatments Demineralisers. Examples of contamination of the membranes Iron Water Treatment Division

Pretreatments Demineraliser. Pretreatment to remove 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 p. H 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. Water Treatment Division

Pretreatments Demineralisers. Examples of contamination of the membranes Solids in suspension Water Treatment Division

Pretreatments Demineraliser. Pretreatments to remove solids in suspension 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. Water Treatment Division

Pretreatments Demineralisers. Examples of contamination of the membranes Organic material Water Treatment Division

Pretreatments Demineraliser. Pretreatments to remove the 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). Water Treatment Division

Pretreatments Demineralisers. Examples of contamination of the membranes Biofilm Water Treatment Division

Pretreatments Demineraliser. Pretreatments to remove the Biofilm 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. 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. Water Treatment Division

Pretreatments Demineraliser. Pretreatments to remove the Biofilm 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. Water Treatment Division

Pretreatments Biocide vs Bisulfite 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. Preparation. To 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. Water Treatment Division

Pretreatments Demineralisers. Examples of contamination of the membranes Lime Water Treatment Division

Pretreatmentss Crystal of Calcium Carbonate (lime) Water Treatment Division

Demineralisers. Examples of contamination of the membranes Scalant process. How are the crystals formed? . IONESION PROTONUCLEUS GROUP FORMATION ARRANGEMENT NUCLEUS CRYSTALS GROWTH 1000 atoms Water Treatment Division

Pretreatments Demineralizer. Pretreatment against lime Water Softener Resin The Calcium and Magnesium are the elements with the most scalant power. It is not used as pretreatment stage for the demineraliser, but it is suitable for water treatment before the boiler inlet. Antiscalant dossing The Calcium and Magnesium are the elements with the most scalant power. The dosage of this element avoids the lime crystal formation. Water Treatment Division

Demineralisers. Examples of contamination of the membranes Difference between antiscalant and water softener Antiscalant effect THRESHOLD EFFECT AGENT (Antiscalant) IONS GROUP FORMATION NUCLEUS ARRANGEMENT CRYSTALS GROWTH Avoids the crystal formation Water Softener effect Ca 2+ (H 2 O) + R-Na+ ---- Na+ (H 2 O) + R-Ca Water Treatment Division

Demineralisers Difference between antiscalant and water softener. Antiscalant doser system + Antiscalant drum Water softener + Salt Water Treatment Division

Demineralisers Difference between antiscalant and water softener. Antiscalant dosage Water softener 2 x 100 litres Consumption of antiscalant product: Salt Consumption: – Daily need of water: 21 m 3 at 70 ºHF. – Necessary regeneration of the water softener every 9 m 3 – Number of regenerations per day: (21 m 3/day) / (9 m 3/ regeneration) = 2. 3 regenerations /day – Consumption of salt per litre of resin in every regeneration: 0, 2 kg/Litres of resin – Consumption of salt in every regeneration: 0, 2 kg/Litre of resin x 100 Litres of resin = 20 kg of salt per regeneration – Salt consumption per day: 2. 3 regenerations / day x 20 kg of salt/regeneration = 46 kg/day – Salt consumption in the same period of time (124 days): 46 kg/day x 124 days = 5. 704 kg = 228 sacks of 25 kg – Daily need of water: 21 m 3 at 70 ºHF. – “High” dosage of product: 5 mg/L = 5 g/m 3 – Daily product consumption: 21 m 3 x 5 g/m 3 = 105 g/day = 0. 105 kg/day – 1 drum of 10 L = 13 kg – So 1 carafe of 10 litres of antiscalant will last: 13 kg / 0. 105 kg/day = 124 days Water Treatment Division

Demineralisers Difference between antiscalant and water softener. Example of calculation Conclusion: In 124 days of use: 5. 704 Kg of salt = 1 bottle of 10 L (13 Kg) Make yourself your calculations: Price/kg Salt x 5. 700 kg salt = EUR spent on salt versus RRP 10 L Antiscalant drum = 189, 00 EUR Water Treatment Division

Pretreatments Selection of the pretreatment for demineralizer. Water sample IT- 11 -56 Test IT- 11 -55 Chlorine Identification and Delivery Laboratory Results of Analysis Advantage: - Less maintenance - Long lasting components - Efficiency - Better water quality Recommended Configuration Introduction of Analysis results Water Treatment Division

Pretreatments Mantenimiento Filtros de Pretratamiento 1. Maintenance each 12 months 1. 2. 3. Checking of conditions of the filter carried out by TAS Istobal Replacement (if is necessary) of the content of the filter carried out by TAS Istobal Collecting the used filter material by an authorized manager of waste, paid by the customer. Water Treatment Division