UV Disinfection
The cleanest final-step kill on the market — no chemistry, no residual, no by-products.
The technology explained.
UV disinfection uses ultraviolet light in the UV-C band (peak germicidal output at 254 nm from low-pressure mercury lamps) to damage the DNA of microorganisms in flowing water. Effective dose is measured in mJ/cm² and is the product of UV intensity and contact time. For potable applications we typically design to ≥40 mJ/cm² (NSF/ANSI 55 Class A), delivering ≥4-log inactivation of bacteria and viruses and validated inactivation of Cryptosporidium and Giardia at substantially lower doses.
- Inactivates bacteria (E. coli, coliforms, Legionella) at validated doses of 20–40 mJ/cm².
- Inactivates viruses including enteric viruses at the same dose range.
- Inactivates protozoan cysts — Cryptosporidium and Giardia — at much lower doses (typically 4–12 mJ/cm²).
- Leaves no chemical residual, no taste change, no disinfection by-products.
- Continuous, automatic operation with logged intensity and lamp-failure alarms.
- Final-step disinfection on every potable train, after RO, UF or media filtration.
- Sites that cannot accept chlorine taste, odour or disinfection by-products (food, beverage, hospitality).
- Wastewater tertiary disinfection before discharge or reuse.
- Aquaculture, hydroponics and food-processing applications.
- ×Not a removal technology — UV does not take anything out of the water; it inactivates pathogens only.
- ×Not effective if upstream water is turbid — suspended solids shield organisms from the UV dose.
- ×Not a residual disinfectant — protection ends at the reactor outlet, so distribution lines need a residual chlorine or chloramine if recontamination risk is present.
- ×Lamp ageing and quartz-sleeve fouling progressively reduce dose — without intensity monitoring, a UV plant fails silently.
Where UV Disinfection is used.
- Final-step disinfection of drinking water
- Wastewater tertiary disinfection before discharge or reuse
- Pool and spa water treatment (with chlorine residual)
- Bottling and beverage water
- Aquaculture and hydroponics
How HidroVerse deploys UV Disinfection.
Almost every potable train HidroVerse signs ends with a UV stage. It is the defensible, no-residual, no-by-products final barrier — sized to ≥40 mJ/cm² on the worst-case feed transmittance, with continuous intensity monitoring, lamp-failure alarms and a quartz-sleeve cleaning schedule built into the maintenance contract. We pair UV with a small residual chlorine dose only where the distribution network creates a recontamination risk.
A typical UV Disinfection treatment chain.
UV almost always sits as a final or near-final stage. Everything upstream must deliver clear, low-UVT water; everything downstream depends on the kill it delivers.
Pre-treatment
The full filtration train — sediment, media, sometimes UF or RO — to deliver feedwater below 1 NTU and with UV transmittance above 85% at 254 nm.
Core stage
Validated UV reactor sized to ≥40 mJ/cm² at the worst-case feed transmittance; continuous intensity monitoring; quartz-sleeve cleaning regime; lamp-failure alarm interlocked to fail-safe valve on critical lines.
Post-treatment
On distribution networks with recontamination risk, a small residual chlorine dose preserves protection between reactor and tap.
Waste handling
Quartz-sleeve cleaning chemistry is collected and disposed; spent UV lamps contain mercury and are returned to a registered recycler.
Buyer's guide.
The questions every commercial buyer should put on the table before signing for a water system. Can't see yours? Send us a brief — a HidroVerse specialist replies within one business day.
Ultraviolet light at 254 nm — produced by low-pressure mercury lamps inside quartz sleeves — damages the DNA of bacteria, viruses and protozoa as water passes through the reactor. Inactivated organisms cannot reproduce and are no longer infective. Dose is measured in mJ/cm² and equals UV intensity multiplied by exposure time.
We design potable systems to ≥40 mJ/cm² (NSF/ANSI 55 Class A). That delivers ≥4-log inactivation of bacteria and viruses, and validated inactivation of Cryptosporidium and Giardia at substantially lower doses. The 40 mJ/cm² target is calculated against the worst-case feed transmittance, not the best.
UV does not remove anything from the water. It is a kill step, not a filtration step. It does not address dissolved chemistry, turbidity, hardness, salts or organics. It also leaves no residual disinfectant, so distribution lines need a small chlorine or chloramine residual if recontamination risk exists.
Yes — significantly. Suspended solids shield microorganisms from the UV dose, and dissolved colour reduces UV transmittance. We never specify UV on a turbid feed; the upstream train must deliver clear water (typically <1 NTU and >85% UVT at 254 nm) before the UV stage.
Low-pressure amalgam lamps: typically 12 000–16 000 operating hours (12–18 months continuous duty). Medium-pressure lamps: 6 000–8 000 hours. Lamp output decays over life, which is why we run continuous intensity monitoring and trigger replacement before dose drops below specification.
Every UV reactor we install carries a UV intensity sensor and a lamp-status alarm. A failed lamp or a dose below the alarm threshold triggers an immediate alert and — on critical-line installs — closes a fail-safe valve so untreated water never reaches the downstream system.
On the immediate point of use, no. UV alone is a validated potable disinfection step. On distribution networks where recontamination risk exists — long pipe runs, storage tanks, pumped boosters — we add a small chlorine or chloramine residual to maintain protection between the reactor and the tap.
Sleeves get coated by hardness scale and organic films, which reduces UV transmittance into the water. Cleaning frequency depends on the feed: monthly to quarterly is typical, with automatic mechanical wipers on commercial reactors. The schedule is in the service contract.
NSF/ANSI 55 Class A for potable applications; USEPA UV Disinfection Guidance Manual for design dose targets; DVGW W294 and ÖNORM M5873 in European references. South African potable systems also deliver against SANS 241:2015 on the product water.
No — that is one of its principal advantages over chlorine and ozone. UV produces no trihalomethanes, haloacetic acids or bromate. It is the cleanest disinfection step available for potable duty.