All the popular packaged water bottle brands you may know, boast of using Reverse Osmosis(RO) to purify their water. While it is considered to be the most popular purification technique, do you know what it means and how it works? What are the factors to consider when you plan to buy a RO water purifier? To answer all your RO related questions, keep reading.
What is Reverse Osmosis?
Reverse Osmosis (RO) is a water purification method that forces water through a semipermeable membrane, filtering out contaminants like minerals, chemicals, and impurities.
In natural osmosis, water tends to travel from the area of lower concentration to a high concentration. Whereas in reverse osmosis, this process is reversed wherein by applying pressure the water moves in the opposite direction, i.e., from high concentration to low-forcing it through the membrane.
Did you know? RO is so effective it’s used by NASA to purify water for astronauts in space!
How Does Reverse Osmosis Work?
RO uses a multi-step filtration system to purify water.
Now, let's break down the detailed 4-step process that makes it all possible:
- Pre-filters
The first of the steps, the pre-filters remove large particles like sand, dirt, and silt. They also take out chlorine, which can damage the RO membrane. This step prolongs the lifespan of the RO system as these harmful particles can clog the filter in subsequent steps.
- Reverse Osmosis Membrane:
In this step, water is passed through a relatively porous membrane called the RO, which filters out microparticles. This filter captures dissolved salts, heavy metals such as lead and arsenic, bacteria and viruses, allowing only the clean water molecules to pass through.
- UV or Ultrafilter:
RO systems usually come with UV lamps or UF filters to deal with harmful microbes. A UV lamp kills 99% of the harmful bacteria and viruses by breaking their DNA. Ultra Filtering(UF) on the other hand uses a hollow fiber membrane which further filters even smaller impurities that may have passed through earlier previous steps.
- Post-filter & Storage :
In the final step, water is filtered through a post-filter, usually an activated carbon filter. The carbon filter removes any unpleasant odor or impurities that remain, making sure the water that you drink is clean and tastes good. Some purifiers feature a TDS (Total Dissolved Solids) controller to ensure critical minerals are reserved while harmful substances are kept at bay.
*** Some purifiers are equipped with”Zero Water Wastage Technology” which recycles rejected water back into household storage tanks
Benefits of Reverse Osmosis Water Filtration:
- Removes 95-99% of contaminants: Effectively removes 99% of microbes, dissolved salts, and dangerous metals like lead, arsenic, etc,.
- Improves taste and odor: Enhances the quality and flavor of drinking water.
- Fully automated process: Operates without manual intervention.
- Cost-saving: Saves money over time compared to purchasing bottled water or paying for delivery services.
- Easy installation: Simple and hassle-free setup for home use.
Drawbacks of Reverse Osmosis Water Filtration:
- Removes essential minerals: Strips beneficial minerals like calcium and magnesium along with contaminants.
- Generates wastewater: Traditional RO systems produce wastewater, although newer models reduce this.
Note: Most RO systems these days include TDS controllers to retain or reintroduce essential minerals for a healthier balance.
How to Choose an RO System and Install It
Evaluate Water Quality: Before choosing an RO system, determine the TDS of your water. If your water has high TDS levels or if it contains harmful contaminants like lead, a more advanced RO system with extra filters like UV or UF may be required.
Compare Countertop and Under-Sink Models: Countertop models are portable and easier to install but are less discreet. Also they hold much lower capacities of water than under-sink models. Under-sink models meanwhile stay hidden and comparatively have a large water holding capacity.
Installation Tips:
- For complex models which involve TDS controllers and UV filters, professional assistance is recommended for installation. This ensures there's no system malfunction and avoids potential leaks.
- Make sure to have your purifier installed near the water source for better efficiency and minimal disruption to your home’s plumbing system.
FAQs
What contaminants does RO remove?
Reverse Osmosis (RO) removes up to 99% of harmful contaminants including dissolved salts, heavy metals (like lead, arsenic, and mercury), chlorine, pesticides, bacteria, and viruses. It is highly effective in reducing Total Dissolved Solids (TDS) and improving water quality.
What is TDS control in an RO system?
TDS (Total Dissolved Solids) control allows you to manage the level of dissolved minerals in your water. While RO removes most minerals, some systems come with a TDS controller that reintroduces essential minerals like calcium and magnesium, ensuring a healthier balance in the purified water.
How does RO compare with other purification methods?
RO is one of the most comprehensive purification methods, effectively removing a wide range of contaminants. Unlike UV filtration, which kills bacteria but doesn't remove dissolved solids, RO physically blocks impurities. Compared to carbon filters, RO systems provide deeper purification, particularly for heavy metals and salts, although carbon filters are often used in tandem with RO for removing odors and chlorine.
