How do different filtration methods compare for effectiveness?
Written by
Robert Kelly
Reviewed by
Prof. Benjamin Murphy, Ph.D.Varying methods of filtration can be used effectively for different contaminants. I tested several systems in a laboratory setup at my home, finding that reverse osmosis was very effective at removing heavy metals. At the same time, UV transmission was best suited for dealing with microorganisms. In all cases, a combination of strategies must be employed to achieve good results regarding fulfilling the various threats present.
Reverse Osmosis
- Removes heavy metals like lead and arsenic
- Eliminates dissolved solids and salts
- Requires membrane replacement every 2 years
Activated Carbon
- Excels at chlorine and VOC removal
- Improves taste and odor effectively
- Doesn't eliminate minerals or microorganisms
UV Purification
- Destroys 99.9% of bacteria and viruses
- Requires clear water for optimal performance
- No chemical residues remain after treatment
Distillation
- Vaporizes water away from all impurities
- Removes minerals along with contaminants
- High energy consumption increases costs
Practical effectiveness depends on the proper maintenance of your system. I experienced a failure of my UV system while camping due to a power outage, allowing bacteria to pass through. Carbon filters will be ineffective when saturated. Regular testing and timely replacement of worn-out components are the only ways to ensure continuous removal of contaminants as promised by the manufacturer.
Marrying methodologies affords a layer of protection against varying threats. I use sediment prefilters and ultraviolet treatment for river water. Carbon stages are employed before reverse osmosis to protect membranes against chlorine attack. This thinking saved my family when contaminated water during a flood showed the inadequacy of single systems.
Water quality testing helps determine the most effective treatment strategy for improving water quality. Initial tests revealed high lead levels, which required the use of reverse osmosis. Bacteria introduced the need for UV treatment. Simple kits indicate the major threats, while professional testing laboratories find complex chemical threats. Tailor solutions to observed contaminant profiles.
The economic and convenience features affect the practical effectiveness of water supply for households. Distillation removes all contaminants; however, these treatments require large amounts of electricity. Filters using gravity do not require any electrical power, but they usually filter the water slowly. I aim to prioritize systems that remove all contaminants, but they must be easy to maintain and affordable.
Read the full article: How to Filter Water: Essential Methods Explained
