Water DNA Pvt. Ltd.

The diagram illustrates the typical stages water passes through, categorized into Pre-Treatment, RO Separation, and Post-Treatment/Ancillaries.

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1. Pre-Treatment Section

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The goal of pre-treatment is to prepare the water for the delicate RO membranes by removing suspended solids, chlorine, and preventing scaling.

• Raw Water Storage Tank: This holds the untreated source water (e.g., municipal, borewell).

• Feed Water Pump: Supplies the necessary pressure to push the water through the initial filtration stages.

• Multimedia Filter (Sand & Anthracite): This is the first major filter. It removes larger suspended solids (turbidity), dust, and sediment down to about 10–25 microns, protecting the downstream components.

• Activated Carbon Filter: This is crucial for removing free chlorine, organic compounds, and substances that cause bad taste and odor. Chlorine must be removed because it can permanently damage the RO membranes.

• Dosing System (Anti-scalant/SMBS):

  • Anti-scalant: Injected to prevent the precipitation and accumulation of hard minerals (like calcium and magnesium scale) on the membrane surface.

  • SMBS (Sodium Metabisulphite): Often dosed after the carbon filter as an added precaution to chemically neutralize any remaining trace amounts of chlorine.

• 5-Micron Cartridge/Security Filter: This is a fine filtration step (typically 5 microns). It acts as a safety guard to catch any fine media particles that might have escaped the earlier filters, protecting the High-Pressure Pump and the RO membranes from scratches and clogging.

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2. RO Separation Section

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This is where the magic of Reverse Osmosis occurs.

• High-Pressure Pump (HPP): This is the most critical pump. It boosts the water pressure significantly (often 150 to 250 PSI or higher, depending on the TDS) to overcome the natural osmotic pressure and force the water through the membranes.

• RO Pressure Vessels: These horizontal vessels house the RO membrane elements. The pressurized water flows across the membrane surface and splits into two streams:

  • Permeate (Product Water) - Green Line: The purified water that successfully passes through the semi-permeable membranes, leaving behind the dissolved salts. This water has a very low TDS.

  • Concentrate (Reject Water) - Red Line: The stream that contains all the rejected dissolved salts and impurities. This water is sent to drain/waste.

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3. Post-Treatment and Ancillaries

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• UV Sterilizer: The Permeate water passes through a UV light system. This is a final safeguard to kill any remaining bacteria or microorganisms that may have passed through the RO process.

• Permeate Storage Tank: The final, purified product water is stored here, ready for use or further distribution.

• CIP (Cleaning-In-Place) Tank & Pump: This is an auxiliary system used to chemically clean the RO membranes when they become fouled or clogged over time. It allows chemicals (acid, caustic, or specialized cleaners) to be circulated through the membranes without removing them from the pressure vessels.

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4. Instrumentation (PI, FI, CT)

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The schematic includes indicators to show where monitoring is done:

• PI (Pressure Indicator): Measures pressure at various points to monitor pump health and potential filter/membrane clogging (e.g., across the filters and at the RO vessels).

• FI (Flow Indicator): Measures the flow rate of the water (e.g., Permeate and Concentrate flow).

• CT (Conductivity Transmitter): Measures the conductivity (which relates directly to the TDS) of the water, primarily to monitor the quality of the Permeate water.