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The nine-step purification process
Water quality at DEOSAI is verifiable, not just claimed. Below is the exact sequence every drop passes through, from raw source water to a sealed, sterilised 19 litre bottle.
Watch the process
An interactive walk through all nine stages. Press play, or step through each stage at your own pace.
Figures are typical performance for each treatment technology. DEOSAI's finished-water quality is confirmed by independent laboratory testing.
Tap any stage below to explore it, or press Play to step through all nine in sequence. Nothing moves until you choose.
Chlorination
Step by step
What happens at each stage
Chlorination
Chlorine is dosed into the incoming raw water to disinfect it and reduce the microbial load before filtration begins. Dosing is held at 0.5 ppm or less and checked at every plant start-up.
First-line disinfection
Sand Filter
Water passes through a sand bed that traps dirt, silt and suspended solids. This clears turbidity and protects the reverse-osmosis membrane further down the line.
Removes suspended solids
Carbon Filter
Activated carbon adsorbs chlorine, organic compounds and volatile organic compounds. It removes the chlorine that would damage the membrane and improves taste and odour.
Removes 90 percent or more of chlorine
Cartridge Filter
A fine, replaceable cartridge captures the remaining fine particles and sediment, polishing the water immediately before reverse osmosis.
Fine 5 micron filtration
Reverse Osmosis
The heart of the system. A semi-permeable membrane forces out dissolved salts, heavy metals such as lead and arsenic, chemicals and any remaining microorganisms.
Removes 95 to 99 percent of dissolved solids
Remineralization
Calcium, magnesium and sodium bicarbonate are added back in measured amounts, restoring a clean, balanced taste and a healthy mineral profile.
Minerals restored
UV Sterilization
Ultraviolet light inactivates any microorganism that survived earlier stages. It is a final safeguard that adds nothing to the water.
Up to 99.99 percent of microbes inactivated
Ozonation
Ozone, a powerful oxidant, destroys any remaining bacteria and viruses and leaves no chemical residue. It is the disinfection method preferred by bottled-water producers.
No chemical residue
Wash, Inspect & Fill
Every returned bottle is inspected and smelled, then washed and sterilised with hydrogen peroxide and hot water at 70 degrees Celsius. Bottles are filled and screened on a fluorescent line, and any that fail inspection are rejected.
Sterilised, filled and screened
Performance figures shown are typical for each treatment technology. DEOSAI's finished-water quality is confirmed by its ISO and PSQCA certified quality systems.
Certified Quality
Verified, not just claimed
DEOSAI water is produced under independently audited quality and food-safety systems, and licensed by the Government of Pakistan.
ISO 9001:2015
Quality Management System. Scope: processing, production, bottling and supply of drinking water.
Certificate No. PKIQS-Q16125131
ISO 22000:2018
Food Safety Management System covering the full production and supply chain.
Certificate No. PKIQS-F41625132
PSQCA Licensed
Licensed by the Pakistan Standards and Quality Control Authority to use the Pakistan Standard Mark for bottled drinking water.
Licence No. CML/N-492/2025 · PSS:4639/2018(R)
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