October 15, 2025
Filtration is fundamental in bottled water production. It helps uphold product quality, extend shelf life, and ensure microbiological safety. Whether the product is still, carbonated, or flavoured, clarity and the removal of unwanted microorganisms remain essential. In mineral water applications, reverse osmosis is used less often, producers typically
rely more on microfiltration, sterile air protection, and colloid reduction to meet hygiene and sensory standards.
Clarifying water at the point of entry
Spring water can contain fine particles, or colloids, that are too small to see but can affect the appearance and strain
membrane filters downstream. To control this, the water is treated with coarse prefiltration. This typically involves depth or
pleated cartridges made from food-grade polypropylene. This stage is vital to reduce turbidity and prevent fouling of finer
filters later in the process.
Core filtration stages in bottled water production
Each step in the filtration sequence is selected to maintain the water’s mineral composition while meeting strict hygiene requirements:
- Microfiltration removes bacteria, colloids, and fine solids. PES (polyethersulfone) and PVDF (polyvinylidene fluoride) membranes are widely applied in sizes of 0.22, 0.45, or 0.65 µm. They offer strong chemical resistance and deliver stable
flow performance.
- Sterile filtration is the final safeguard before filling. These filters help prevent contamination without compromising the flavour or mineral balance of the water. Atlas Copco sterile filters are validated for use in beverage environments and offer dependable performance with minimal extractables.
- For carbonated water, sterile air and vent filters are necessary. They help protect pressurized tanks and CO₂ injection systems from microbial intrusion.
- In flavoured water lines, carbon filters may be added to remove off-odours or help stabilize taste. This step is optional and depends on specific ingredients.
Cleaning and disinfection practices
Maintaining clean filtration systems is key to safe production. While many operations use clean-in-place (CIP) systems, others follow alternative methods. According to field feedback, effective approaches include:
- Caustic soda / sodium hydroxide rinses to eliminate bacteria
- Phosphoric acid to dissolve mineral crusts
- Peracetic acid as a strong disinfectant
- In systems without CIP, ozone (O₃) between 0.1 and 0.3 ppm may be used to deactivate Pseudomonas.
Still, ozone must be applied with caution, improper use, especially in water, can result in bromate formation, which is strictly regulated due to safety concerns.
Filtering Pseudomonas aeruginosa typically involves an Atlas Copco PES or PVDF membrane rated at 0.45 µm, which effectively traps the bacterium for analysis and control. In addition, specific media and incubation conditions, such as those used in the mPA procedure, can enhance the recovery and identification of P. aeruginosa.
System design in bottled water filtration
Effective filtration depends on sound system design. Key features include:
- SUS316 stainless steel housings, known for food-grade compatibility and corrosion resistance
- Modular filter housings to accommodate high flow rates or parallel filtration
- Hygienic design for ease of cleaning and sterilization
- Pressure-rated components in carbonated lines to withstand CO₂ handling
- Stainless steel housings designed for CIP and SIP compatibility
These filtration setups support high flow rates, microbial integrity, and compliance with key food-grade standards.
Inline filter systems must also be accessible for regular integrity testing and cartridge replacement, which is critical for maintaining compliance.
Regulatory and quality compliance
Filtration in bottled water must comply with global food safety requirements. These include:
- FDA, IBWA, and WHO guidelines covering microbial and particle limits
- Food safety certifications like ISO 22000 and FSSC 22000
- Integrity and retention validation for sterile filters
All filter materials should be food-safe and fully traceable. Documentation, maintenance logs, and scheduled change-outs are essential for audit readiness and internal checks.
Filter replacement: a key operational focus
About 80% of filtration demand in the bottled water industry comes from replacing filters. This includes:
- Prefilters used for turbidity reduction and particle removal
- PES and PVDF membranes used in final and sterile filtration (in 0.22, 0.45, or 0.65 µm ratings)
- Depth and pleated cartridges for colloid and microbial control
Maintaining a replacement schedule helps ensure product safety and supports continuous production in high-output
facilities.
Supporting flavoured and carbonated products
Filtration isn’t just for still water. Carbonated lines require durable, pressure-resistant components and sterile venting.
In flavoured water production, extra polishing filters can help preserve clarity and support consistent flavour profiles.
By adapting the filtration process to each product category, producers can meet their safety goals while delivering high
quality outcomes.
Atlas Copco filtration solutions
Atlas Copco offers a complete filtration range tailored to bottled water producers, including:
- PES and PVDF sterile membrane filters in 0.22, 0.45, and 0.65 µm
- Depth and pleated cartridges made from polypropylene and glass fibre in nominal and absolute ratings
- Sterile air and vent filters
- Hygienic stainless-steel housings compatible with CIP and SIP cleaning systems
These systems are built for microbial control, high throughput, and full compliance with food safety regulations.
Filtration is central to bottled water production. From colloid removal to final-stage venting, each filtration phase helps
maintain product integrity. With the right membranes, cleaning routines, and system design, producers can meet regulatory demands
and deliver consistently safe, clear water.
Need help designing your filtration setup? Speak with an Atlas Copco expert today.
