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RO vs UV Water Purification — What Each Does & When to Use Both
RO and UV do completely different things. This guide explains what each does, what it cannot do, when to use them together, and why Lahore bore water typically needs both.
🔧 Aqua Prima, Ichhra, Lahore: Based near Shama Chowk, Hamza Hospital, FMH College and Ferozepur Road. Direct experience with bore water quality across Lahore localities.
Technology Comparison
RO vs UV — What Each Technology Does and Does Not Do
| Factor | Reverse Osmosis (RO) | UV Disinfection | Important Nuance |
|---|---|---|---|
| Reduces TDS | Yes — 95–99% | No — zero effect on TDS | UV cannot fix a high-TDS problem |
| Removes hardness | Yes | No | Scaling is an RO concern, not a UV concern |
| Removes arsenic, lead, fluoride | Yes — 85–99% | No | UV has no effect on dissolved heavy metals |
| Kills bacteria | Yes — 99%+ physical exclusion | Yes — DNA damage prevents reproduction | UV provides additional layer after RO for drinking water |
| Kills viruses | Yes — 99%+ quality membranes | Yes — most waterborne viruses | UV recommended post-RO for drinking water assurance |
| Removes dead organisms | Yes — physically excluded | No — killed but remain in water | RO physically removes; UV kills but organisms stay |
| Works on turbid water | Pretreatment removes turbidity | No — particles shield organisms from UV | UV requires pre-clarified water to be effective |
| Annual maintenance | Filters + membrane every 2–4 yrs | UV lamp replacement annually | UV lamp must be replaced even if it appears lit |
| Capital cost | PKR 28,000 – 3,500,000+ | PKR 8,000 – 50,000 (standalone) | UV adds small cost to an existing RO system |
Lahore Recommendation
RO, UV or Both — What Lahore Bore Water Needs
| Lahore Zone | Typical TDS | Microbiological Risk | Recommended Configuration |
|---|---|---|---|
| Ichhra, Shama (bore water) | 900–1800 ppm | High (urban bore) | RO + UV + full pretreatment |
| Samanabad, Rehmanpura | 700–1600 ppm | High (urban) | RO + UV + pretreatment incl. softener |
| Muslim Town, Garden Town | 600–1400 ppm | Medium to high | RO + UV (pretreatment: test first) |
| Gulberg, Model Town | 500–1200 ppm | Medium | RO + UV (test pretreatment needs) |
| WASA municipal supply | 200–500 ppm | Low–medium (chlorinated) | Carbon + UV if microbiological concern; RO if TDS elevated |
Note: Lahore bore water has both high TDS AND microbiological risk. UV alone delivers disinfected but high-TDS water — not suitable for drinking. RO alone provides strong microbial rejection but UV adds an important second safety barrier for drinking water businesses.
People Also Ask
FAQs — RO vs UV
Can UV replace RO for Pakistani bore water?
No. UV has no effect on TDS, hardness, arsenic or any dissolved chemical. For Pakistani bore water with typical TDS of 700–2000 ppm, UV alone delivers disinfected but high-TDS water that is not suitable for drinking. RO is required to address the dissolved-solids problem.
Can RO replace UV?
RO provides very high microbial rejection (99%+) through physical size exclusion. For many applications this is sufficient. However, UV post-treatment adds an additional safety layer for drinking water, particularly in Lahore where source water carries significant microbiological load. The cost of a UV lamp (PKR 8,000–20,000) is small relative to the value of the additional disinfection barrier.
How often does a UV lamp need replacing?
Annual replacement regardless of lamp appearance. UV lamp output degrades over time even when visibly lit. A lamp beyond 12 months may produce less than 50% of its rated UV output — insufficient to disinfect at rated flow rate. For commercial water businesses serving the public, annual UV lamp replacement is non-negotiable.
How much does a UV system add to RO plant cost?
A UV unit adds approximately PKR 8,000–20,000 for a domestic system and PKR 25,000–80,000 for a commercial system to the RO plant cost. Annual lamp replacement is PKR 1,500–8,000. This is negligible relative to the value of additional disinfection assurance for a water business.
Does UV work on turbid water?
No. Particles in turbid water scatter and absorb UV light, shielding microorganisms from the disinfecting effect. UV must be used on pre-clarified water. In an RO system, pretreatment stages produce low-turbidity water before UV — making RO + UV an effective combination.
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Aqua Prima recommends the right combination of RO and UV for your water and application. Ichhra, Lahore.
📍 Ichhra, Lahore | 0327 457 5527