water treatment division incrustation calcium carbonate, magnesium carbonate, calcium phosphate,...

Water Treatment Division

IncrustationCalcium carbonate,

Magnesium carbonate,

Calcium phosphate,

Magnesium phosphate

Barium or Calcium phosphate

Calcium fluoride

InorganicSilica

Clays

Aluminium

Iron

Manganese

OrganicHydrocarbon

Humic acids and fulvics

Cationic Polielectrolite

Biological

Bacteria

Fungus and yeast

Polymer extracellular

Disinfection or Bacteriostatic

Active carbon absorption

Antiscalant orWater softener

Different previous filters

Prevention or process delay

Membranes, Getting dirty and obturation

Demineralisers. Critical issue: contamination of membranes

Pretreatments


Demineralisers. Critical issue: contamination of membranes

The membranes are contaminated by several causes:

Pretreatments

Iron

Chemical oxidation damage

Excess pressuredamage

Collodial Material

Compaction

Biological Pollution

Scaling by silica

Biological Pollution


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 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.

Pretreatments

Demineralisers. Pretreatments to remove Chlorine


Iron

Demineralisers. Examples of contamination of the membranes

Pretreatments


Iron removerThe 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


Solids in suspension


Pretreatments


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


Organic material


Pretreatments


Organic Material filterOrganic 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


Biofilm


Pretreatments


BisulfiteThe 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


BiocideIt 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


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


Lime


Pretreatments


Crystal of Calcium Carbonate (lime)

Pretreatmentss


Scalant process. How are the crystals formed?.

IONESION PROTONUCLEUS NUCLEUS CRYSTALS

ARRANGEMENTGROUP FORMATION GROWTH

1000 atoms

Demineralisers



Pretreatments

Water SoftenerThe 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.

Demineralizer. Pretreatment against lime

Antiscalant dossingThe Calcium and Magnesium are the elements with the most scalant power. The dosage of this element avoids the lime crystal formation.

Resin


Antiscalant effect

Avoids the crystal formation

Difference between antiscalant and water softener

Water Softener effect

Ca2+ (H2O) + R-Na+ ---- Na+ (H2O) + R-Ca

IONS IONS

GROUP FORMATION ARRANGEMENTGROWTH

NUCLEUS CRYSTALS

THRESHOLD EFFECT AGENT

(Antiscalant)

Demineralisers



Difference between antiscalant and water softener.

Antiscalant doser system

+Antiscalant drum

Water softener+

Salt

Demineralisers


Water softener 2x100 litresSalt Consumption:

– Daily need of water: 21 m3 at 70 ºHF.– Necessary regeneration of the water softener

every 9 m3 – Number of regenerations per day: (21m3/day) /

(9m3/ 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

Antiscalant dosageConsumption of antiscalant product:

– Daily need of water: 21 m3 at 70 ºHF.– “High” dosage of product: 5 mg/L = 5 g/m3 – Daily product consumption: 21m3 x 5 g/m3 =

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


Demineralisers


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

Example of calculation

Demineralisers



Water sampleIT- 11-56 TestIT- 11-55 Chlorine

Recommended Configuration

Laboratory

Introduction of Analysis results

Results of Analysis

Selection of the pretreatment for demineralizer.

Pretreatments

Identification and Delivery

Advantage: - Less maintenance - Long lasting components - Efficiency - Better water quality


1. Maintenance each 12 months1. Checking of conditions of the filter carried out by TAS Istobal2. Replacement (if is necessary) of the content of the filter carried out by TAS

Istobal3. Collecting the used filter material by an authorized manager of waste, paid

by the customer.

Mantenimiento Filtros de Pretratamiento

Pretreatments

water treatment division incrustation calcium carbonate, magnesium carbonate, calcium phosphate,...

Documents

iron slide

iron removal treatment

chlorine slide

pretreatments demineralisers

carbon surface

continued water flow

carbon leads

ro treatment