In industrial water bottling applications, many water treatment technologies are used to ensure that water meets extreme quality requirements governing products intended for human consumption. When these filtration systems fail, contaminants can make their way into finished water bottles and cause issues ranging from product waste to serious customer illness. Very often, flow restrictions and clogs show up in these filtration systems just before a major failure occurs. As such, water bottling system operators must be mindful of spotting, addressing, and resolving filter clogs before they pose a risk to consumers.
In the United States, the federal Environmental Protection Agency (EPA) and the Food and Drug Administration (FDA) share responsibility for the safety and quality of drinking water consumed across the nation. For bottled water in particular, the FDA requires that bottlers:
- Process, bottle, hold, and transport bottled water under sanitary conditions
- Protect water sources from bacteria, chemicals and other contaminants
- Use quality control processes to ensure the bacteriological and chemical safety of the water
- Sample and test both source water and the final product for contaminants
Filtration systems fill a critical role in achieving these requirements, as they are usually the sole defensive mechanism protecting human health from waterborne contamination. To satisfy these regulations, water bottlers are required to treat any potential filtration issues (including clogs) as looming risks to human safety. It’s that important.
Understanding the Many Sources of Filtration System Flow Restriction
Now that we understand the weight of keeping bottled water filtration systems free of flow restrictions, let’s look closer at these filtration systems themselves.
Water filtration is a technology category encompassing many types of equipment and processes that remove unwanted constituents from a water stream. In water bottling applications, any single or combination of technologies can be found including sand filters, resin beds, perforated metal screens, woven socks, membrane cartridges, carbon charcoal, and more.
All filters restrict contaminants from flowing through them based on physical size, catching and retaining unwanted particulates within the filter media itself. Over time, these contaminants build up on the filter media’s surface, blocking flow paths through the filter. As the open surface area decreases, flow through the filter also decreases. Once flow is below an acceptable rate, the filter is considered to be clogged.
Flow restriction in filters is most often caused by the contaminant overloading that we just described, but it can also be a function of the type of contaminants being filtered out as well as wider system upsets. Biological films, spore blooms, mineral agglomeration, temperature spikes, pump issues, piping corrosion, sensor calibration faults, and so on – all are examples of systemic factors that can reduce filtration flow.
Next, let’s address the connection between clogging and the consumer health risks mentioned earlier, which are:
- Filters that clog with biological and organic materials may leech smaller size particles that will pass forward of the filter, contaminating the water beyond FDA and EPA limits. Recent bottled water recalls have proven this risk, testing positive for coliform, bacteria, non-viral hepatitis, and E. coli.
- Clogged filters require higher inlet pressures to overcome the flow restriction, which can force particulates that are larger than the filter’s size rating through the media. As such particulates are forced through, they leave larger and larger openings in the filter’s surface, providing a wide-open path for contaminants. Once these oversized paths are created, the filter is completely compromised and cannot provide its intended level of protection.
Strategies to Ward Off High-Volume Water Bottling Filtration System Clogs
In most bottled water facilities, filtration systems serve as the last line of defense against contamination from upstream sources. To combat the risks of filtration system failures stemming from filter clogging, let’s review several strategies that bottling plant managers can implement:
Technological Strategies
- Pre-Filtration – filters can clog quickly when they are asked to filter out particulates that are much larger than their ideal rating. Installing upstream pre-filters helps remove larger particulates separate from final filtration, reducing the loading and increasing the lifespan of both filters.
- Automated Flow Controls – too often, operators manually adjust flow and pressure controls on a filter system’s feed pumps in an effort to overcome initial loading and speed up throughput. Installing automatic flow controls can automate this process, restricting the pumps from exceeding flow setpoints and alerting operators when clogging is first detected.
- Automatic Purge – many filtration systems can be outfitted with an automatic purge system, which automatically backflushes the accumulated particulates from the filter media and flushes them to drain. In this way, filter loading is reduced in place which helps to keep flow rates and pressures within specifications.
Operational Strategies
- Operator Inspections & Monitoring – bottling filtration system operators often receive solid functional training (E.G., “how it works”) but insufficient application training (“why it works”). Plant managers should expand training to include inspection and monitoring for emerging filtration issues such as clogs, ensuring that operators understand filtration mechanics, water chemistry, and water quality fundamentals.
- Routine Maintenance – there is no replacement for thorough, routine maintenance performed on all water bottling filtration systems to keep components, instrumentation, and hydraulics in calibration and good physical working order. In addition, maintenance rounds are often the only time that water filtration systems get fully opened up for a close look inside where hidden problems can be found (such as biofilm growth and filter media degradation).
- Water Quality Management – all filtration systems are designed for a specific feed and discharge water quality specification, and both streams must be actively managed against that specification. Discerning bottlers will take frequent water quality samples throughout the year, testing for pH, mineral, particulate, and other quality deviations. Such deviations can serve as early indicators of issues (such as clogs) and drive proactive adjustments to the filtration system’s media or operating parameters.
What Filtration Clogs Tell Us about Total System Integrity
Water filtration is certainly not “one size fits all”. All of the many challenges that industrial water bottlers experience with their filtration systems is a testament to just how critical it is to design each system specific to each individual plant. By their very nature, filtration systems catch issues that originate somewhere else in the overall water bottling process, and so any issue with a filtration scheme is in some way directly tied to the health of the wider plant. For this reason, we encourage bottling plant managers facing filtration challenges to pause and consider their overall system, as the issues are surely some combination of water quality, equipment, filtration media, and operational factors. Benchmarking an entire water bottling plant’s performance is a perfect way to establish an operational baseline to measure against, giving managers the information needed to catch issues before they become FDA-level problems anywhere in their process – filtration clogs or otherwise.