Household drinking water either comes from a public water system, a private well, or bottled water. For the most part, Americans do not have to worry too much about the safety of their water. Tapped water is often safe enough for drinking without any further purification. So, what’s all this talk about water filtration?
If you drink tap water from an EPA-regulated public water management system, then your tap water is probably safe enough to drink without the need for filtration to remove water-related bacteria or diseases. The standards for EPA-regulated water management systems are more stringent than those of bottled water.
That said, your water could easily get contaminated with lead from the plumbing, so it is better to be safe than to be sorry. A water filtration system will remove not only lead but any other contaminants in your water.
Homes with private waste management systems (like septic systems) are susceptible to groundwater contamination. Even though septic systems do a pretty good job of treating wastewater, there is always the lurking danger of contamination of your water well.
The World Health Organization warns that drinking contaminated water can cause diseases like dysentery, cholera, typhoid, polio, and diarrhea. If you have a private well, installing a water filtration system is in your best interest.
What do water filters remove from drinking water?
Most people would agree that filtered water tastes great – but water filtration achieves much more than just give your water a nice taste.
Here are some of the contaminants that a water filtration system can eliminate from your drinking water:
- Minerals
- Suspended solids
- Pathogens
- Chemicals
- Lead
Minerals
Water often contains non-hazardous minerals like iron, manganese, and calcium. While these minerals are harmless, they tend to give water a somewhat unpleasant taste. Some of these minerals can also stain porcelain, clothes, or dishes. Thankfully, they can easily be removed by water filters.
Suspended solids
Water filtration does a perfect job of eliminating suspended solids from drinking water. Sediments like silt, dirt, clay particles, leaves, and any other debris can be removed through filtration.
Most of this debris may not necessarily be harmful but they lower the quality of water nonetheless.
Pathogens
It is not uncommon for drinking water to get contaminated with bacteria, viruses, and protozoa, especially if you have a septic tank. Even if you are sure your system is fine, your water well could just as easily get contaminated by a neighbor’s septic system.
That’s why you want to filter your water using Nanofiltration, which is very good at removing all manner of pathogens from water.
Chemicals
Most of modern-day pesticides readily dissolve in water, and this can easily result in groundwater contamination. Then there is the problem of the household chemicals that we send down the drain.
A single household is estimated to send hundreds of chemicals down the drain every month. Since these chemicals easily dissolve in water, they can easily seep into the groundwater and back into your water well. Luckily, you can easily filter out these harmful chemicals by using an active filter.
Lead
Lead is pretty common in drinking water. It usually seeps into the groundwater from old plumbing. In fact, it is recommended that every homeowner with a water well to test their water for lead at least once every year.
Special filters are designed to remove metals in water, and they would be ideal for filtering lead out of water.
Membrane filtration techniques
By definition, filtration is the process by which suspended solids, liquids, or gases adhere to the surface of an absorbent medium.
The effectiveness of filtration is highly influenced by the amounts of the contaminant and the particle size of the contaminants.
Three main types of membrane filtration techniques are used in water filtration systems:
- Microfiltration
- Ultrafiltration
- Nanofiltration
Microfiltration
Microfiltration is a process by which suspended solids are removed from water through a physical membrane. Unlike the other techniques, microfiltration only uses physical filtration to eliminate suspended particles in the range of 0.1-10 microns.
Microfiltration can, therefore, remove most suspended solids and some bacteria but it doesn’t remove dissolved contaminants.
Ultrafiltration
Ultrafiltration (UF) utilizes concentration gradients or standard home water pressure to push the water through a 0.2-micron membrane, thereby filtering out the contaminants.
Ultrafiltration does a pretty good job of filtering out bacteria, viruses, and other parasites, but it retains the minerals in the water, which makes it a more desirable alternative to reverse osmosis.
Nanofiltration
Nanofiltration is a relatively new pressure-driven technique that is somewhere in between reverse osmosis and ultrafiltration. The nanofiltration membranes are typically 1-10 nanometers which makes them smaller than the ones used in ultrafiltration or microfiltration but at the same time larger than the ones used in reverse osmosis.
As you may have guessed, the three techniques give different water quality levels. When choosing a water filtration system for your house, it is a good idea to start by determining what contaminants you are dealing with. Then you can use the contaminants as the determinant for the technique to choose.
The table below gives a summary of the contaminants and the techniques that are best suited for them.
| Bacteria | Virus | Chemicals | Protozoa | |
| Microfiltration | Very effective | Moderately effective | Not effective | Not effective |
| Ultrafiltration | Very effective | Very effective | Moderately effective | Low effectiveness |
| Nanofiltration | Very effective | Very effective | Very effective | Moderately effective |
Pretreatment is often included in home-based water filtration systems to ensure the filtration is as effective as possible. some of the commonly used pretreatment methods include the addition of powdered activated carbon, coagulants, or the adjustment of the pH and Chlorine concertation levels.
These pretreatment processes also help to protect the surface of the membrane on the surface of the filters.
So, in summary, water filtration is actually very necessary for anyone that doesn’t have EPA-regulated public water. But even if you do, you can still use a water filter just to be safe and make your water taste better.
