Packaged drinking water is only as good as the treatment behind it. A bottling line can be perfectly clean and still produce a failed sample if the water arrives with a microbial problem or the disinfection step is not correctly balanced. Understanding how reverse osmosis, UV and ozonation work together, and how they connect to the filling line, helps owners avoid costly failures in testing and in the market.
Reverse Osmosis: Removing Dissolved Solids
RO forces water through a semi-permeable membrane that holds back most dissolved salts and impurities. It reduces total dissolved solids to a low level, after which minerals are often dosed back to improve taste and meet product standards. RO is not intended as the final barrier against microbes; it is a purification step that prepares water for disinfection.
UV Sterilisation: Inactivating Microbes in Flow
UV lamps expose flowing water to ultraviolet light, which damages the genetic material of bacteria and viruses and prevents them from multiplying. UV is effective when the water is clear and the lamp is clean and within its rated life. It has no residual effect, so water can be recontaminated after the UV unit if the system downstream is not clean.
Ozonation: A Residual Safeguard
Ozone is a powerful oxidant that disinfects water and leaves a small residual that continues to act for a short time, including inside the sealed bottle. Ozone then breaks down into oxygen, leaving no chemical residue. This makes ozonation a popular final step before filling.
Getting the Ozone Dose Right
Too little ozone may not provide enough protection. Too much can produce off-tastes and, in waters containing bromide, may lead to unwanted by-products. The aim is a controlled, measured residual at the filler. Many plants monitor ozone concentration and adjust dosing with care, working with their water treatment supplier.
The Contact Tank
Ozone needs contact time to work. A contact tank after the ozone injection point holds water long enough for disinfection. From this tank, water flows to the filler. The tank and pipework should be made of materials that tolerate ozone, such as stainless steel.
Connecting to the Filling Line
The filler is the last stage where water touches equipment before the bottle is sealed. Its tanks, valves and pipework must be cleaned and sanitised regularly. A clean filler protects the quality that water treatment has achieved. Key practices include:
- Regular cleaning and sanitisation of filler tanks and valves
- Rinsing bottles with treated water or ozonated water
- Keeping the filling area enclosed or covered
- Avoiding stagnant water in pipework during shutdowns
Testing and Monitoring
An in-house laboratory should test water at different points: raw water, after RO, after UV and from finished bottles. Testing at each point helps locate problems quickly if a sample fails.
Records That Help During Audits
Keep daily logs of RO output quality, UV lamp hours and ozone readings. These records support your licence inspections and help pinpoint the cause quickly if a test result is ever out of limits.
A System, Not a Set of Machines
Treatment and bottling equipment are often bought from different suppliers. Making sure they are sized and connected correctly, with proper flow rates, storage and sanitisation, is essential.
Hilden supplies rinsing, filling and capping machines for packaged drinking water and works with treatment specialists to integrate the full system. If you are planning a new plant or troubleshooting quality issues, the team can help review the connection between treatment and filling.
