CAN, REVERSE ÓSMOMSIS MEMBRANES, REJECT VIRUSES & BACTERIA?Reverse osmosis membranes offer a very high rejection capability for bacteria and viruses, above 99.9%. However, as in all water purification operations which employ reverse osmosis membranes, the oxidation potential of the same and loss of mechanical integrity (physical damage) can greatly reduce this rejection. In certain cases, microbial growth may occur in the permeate side.
HOW OFTEN SHOULD CLEAN A REVERSE OSMOSIS PLANT?Generally, manufacturers recommend cleaning membranes of reverse osmosis installation when there is a decrease of 10% of the normalized flow. As a guide, one can say that, for a plant that treats water with a 3.0 SDI expect a frequency of cleanings could double. However, the actual frequency will depend on each individual case.
WHAT EFFECT DOES T.O.C. (TOTAL ORGANIC CARBON) ON THE MEMBRANES OF REVERSE OSMOSIS AND NANOFILTRATION?Circulating water is recommended to move the low pressure air that can be a membrane and the pressure box. This movement should be done in a pressure range from 0.2 to 0.4 MPa. In making this operation, the flow of permeate and concentrate produced will go to drainage. The air remaining in the elements and / or pressure boxes, if the start-up speed is too high, can cause stress in the radial direction of flow or causing breakage in the glass fiber casing of the membranes.
DO I NEED TO PURGE THE AIR OF A REVERSE OSMOSIS SYSTEM BEFORE EACH START?Se recomienda circular agua a baja presión para desplazar el aire que pueda haber un las membranas y las cajas de presión. Este desplazamiento se debe hacer en un rango de presión de 0.2 a 0.4 MPa. Al hacer esta operación los caudales producidos de permeado y concentrado irán a drenaje. El aire que queda en los elementos y/o las cajas de presión, si las velocidad de puesta en marcha es muy alta, puede provocar tensiones en la dirección del flujo o radiales causando roturas en el envoltorio de fibra de vidrio de las membranas.
MEMBRANES AFTER LIFE, CAN YOU DISPOSAL TO A NORMAL DUMP?Since the materials that make up the elements of reverse osmosis are non toxic materials, they have no restrictions on of being thrown into a landfill normal as any other local laws. As the membranes used may have accumulated deposits of the feed solution have tried, it is important to consult local or national legislation specific to each particular situation.
CAN THE SILICA BE ELIMINATED FROM WATER?The silica is present in two forms: reactive silica and colloidal silica. The colloidal silica has virtually no ionic character but has a relatively large size. The colloidal silica can be removed by mechanical barriers such as reverse osmosis. It may also be reduced by agglomeration techniques as those used in the classifiers. Techniques based on the ionic charges such as ion exchange and continuous deionization (CDI) has little impact on the removal of this type of silica. The reactive silica is a molecule much smaller than the colloid. Consequently, most techniques such as mechanical removal flucuación, clarification, filtration and flotation are not able to eliminate them. The technologies are allowed eliminate reverse osmosis, ion exchange and Continuous Deionization.
WHAT PARAMETERS MUST BE ANALYZED TO DESIGN A SYSTEM FOR REVERSE OSMOSIS OR NANOFILTRATION?Before proceeding with the design of a reverse osmosis plant or nanofiltration should have a complete analysis of the water to be treated.
This analysis of water should be balanced, i.e. concentrations of anions and cations should be identical in units of equivalent calcium carbonate.
If water analysis is not balanced, we recommend the addition of Na +O or Cl -, as appropriate, to achieve the ionic balance.
A water analysis example might be:
Temperature (° C);
Analysis of water. Specify units (mg / L as CaCO3 ion or ppm or meq / L);
NH 4 +
CO3 (2 -)
Mg 2 +
SO4 (2 – )
PO4 2 –
S 2 –
Mn 2 + SiO 2 (colloidal)