Most of us would know what a filter is. Well, it has been covered in some parts of the school science syllabus. Filters are commonly found and used in numerous places. We know to some degree what it does. Yet, not many of us delve into the specifics of filters and what we may NOT know, may sometimes cost us dearly.
So firstly, we need to know what a filter is. To be grammatically correct, a filter is “A porous material through which a liquid or gas is passed in order to separate the fluid from suspended particulate matter.”[1] To be more scientifically precise, “Filtration is a physical process that removes these impurities from water by percolating it downward through a layer or bed of porous, granular material such as sand. Suspended particles become trapped within the pore spaces of the filter media, which also remove harmful protozoa and natural colour.”[2]
Additionally, filters these days have expanded in terms of functionality. On top of basic filtration which removes sediments from the water, advanced filtration systems also boast abilities to improve the water quality, increase mineral content in the water and even change the water’s pH.
Now that we know what a filter is supposed to do, we also have to understand what it is not expected to do. Here, I have collated 5 Myths that I have often encountered when speaking with different customers and here’s the Truth behind each statement.
1) “Filters can kill bacteria”
Possible. It however depends largely on the material used in the filter and if it has anti bacterial capability. Most filters would typically use silver activated carbon for its anti-bacterial ability.[3] There is however a limit to the amount of bacteria that silver can kill. Hence, with the prolonged usage of a filter, it will result in a drop in its ability to kill bacteria. Thus, it is necessary to change the filter regularly, else it would not be able to effectively ‘kill bacteria’. Thus, one shortcoming of filters is the difficulty to identify when the anti-bacterial ability of filters wear out.
Another function of filters is to trap sediments and should the filter be fine enough, it would also trap bacteria. There is however a limit to the amount of bacteria and sediments that a filter can trap. Often, I have encountered filters that produce water that is worse than that of the local municipal water. This is largely due to an excessive overuse of filters that was used beyond the limit.
2) “Filters can filter everything”
Not true. A statement that uses an absolute like ‘everything’ can hardly be true. Even with the hyperfiltration ability in membrane technology (0.5 nanometer)[4], water is still able to be removed, so filters do not filter out everything.
However, if we add the caveat of ‘everything’ referring to sediments and particulates, then it is possible for very specific types of filters to effectively remove most particulates, again not 100%. Such specific types of filters refer to reverse osmosis membranes and desalination membranes and are not referring to basic filtration.
3) “More filters = better filtration”
Not true. Based on arguments above, it is clear that filters have a wide variance in terms of sizing to filter. Hence, it is not the number of filters but rather the porosity of filters that determine the quality of filtration.
Some filtration systems often have a number of components that could be reflected as separate ‘filters’ with each component serving a specific purpose in the overall scheme of filtration. This however should not be taken to mean that it would result in better filtration. It is ultimately the output of water that is determined by the porosity of filters that determines whether it is good filtration.
For a local Singapore context, having multiple filters pose a few issues. Firstly, the more filters the water has to pass through, the greater the drop in water pressure. This would result in a slow water flow as well. Another concern is that with more filters, a user would have higher replacement cost and this may not be worthwhile especially, if the replacement filter is not necessarily required. Also, another concern with multiple filters is the downward transference of bacteria and sediments from the 1st filter on to subsequent filters that will affect the overall water output quality.
4) “Filters don’t have to be changed.”
Not true. If filters do not have to be changed then, then it would be akin to batteries that could last forever and never need to be changed. Filters have a limit to which it can be used, after which it has to be changed for the quality of water to not be compromised.
Most home filters are usually primed for 6-8000 liters of water, even though some companies may claim to offer up to 10000 liters. However, beyond the optimal capacity of filtration, it may not function as well as it ought to.
5) “Filters can ONLY remove, it does not add anything in”
Not true. Whilst the basic function of filters as described above is to remove the particulates and sediments in the water, it is also possible for other materials in the filter to serve other functions. An example would be the likes of our 0.01M filters. One of the components, the Tourmaline Bio Ceramic stones serve to provide FIR (far-infrared) energy that helps to energize and oxygenates the water. Another component within our filters would be the Coral Calcium. This segment primarily serves to neutralise the chemicals in the water, however, it also aids in providing additional Calcium in the water, which helps to improve ionization in soft water conditions.
And that brings to a close some of the more common myths that people harbour about filters. In the next post on filters, we would explore different filtering materials in detail.
Should you have any queries or need more clarification, do feel free to contact us at +65 6272-5337 / 6223-2267 or simply email us at sales@kemptrading.com
IK
More information can be found at our company’s site, www.kemptrading.com.
[1] http://www.answers.com/topic/filter
[2] water supply system. (2011). In Encyclopædia Britannica. Retrieved from http://www.britannica.com/EBchecked/topic/637296/water-supply-system
[3] http://en.wikipedia.org/wiki/Silver#Medical
