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Drinking Water Contaminants and Their Control with Reverse Osmosis Water Treatment

Clean and safe drinking water is essential for maintaining good health. However, water sources are susceptible to various contaminants that can adversely affect human well-being. In this blog post, we will explore common drinking water contaminants and discuss how reverse osmosis (RO) water treatment can effectively eliminate them, providing you with pure and healthy drinking water.

Understanding Drinking Water Contaminants

      1. Heavy Metals: Heavy metals like lead, arsenic, mercury, and cadmium can seep into the water supply through natural deposits, industrial discharges, or aging infrastructure. Prolonged exposure to these contaminants can lead to serious health issues, including neurological damage, organ failure, and developmental problems.

      2. Microorganisms: Bacteria, viruses, and parasites pose significant risks to public health. They can enter the water supply through sewage leaks, agricultural runoff, or inadequate water treatment systems. Waterborne diseases such as cholera, dysentery, and typhoid can result from consuming water contaminated with these microorganisms.

      3. Chemicals: Chemical pollutants, including pesticides, herbicides, industrial solvents, and pharmaceuticals, can contaminate water sources. These chemicals can have long-term health effects and are linked to cancer, hormonal imbalances, and reproductive issues.

      4. Sediments and Suspended Particles: Sediments and suspended particles such as sand, silt, and rust not only affect the aesthetic quality of drinking water but also clog pipes and appliances. Moreover, they can harbor harmful bacteria and impede the efficiency of water treatment systems.

Reverse Osmosis Water Treatment: The Solution

Reverse osmosis is an effective water treatment method that can remove a wide range of contaminants and provide clean, safe drinking water. Here's how it works:

      1. Filtration Process: Reverse osmosis systems use a semi-permeable membrane to filter out impurities. Water is forced through the membrane, which acts as a barrier, allowing only pure water molecules to pass through while rejecting contaminants. This process eliminates up to 99% of dissolved solids, microorganisms, and suspended particles.

      2. Removal of Heavy Metals: Reverse osmosis systems effectively remove heavy metals such as lead, arsenic, and mercury by capturing them within the membrane. This ensures that your drinking water is free from these harmful substances, reducing the risk of associated health problems.

      3. Microorganism Elimination: The fine pores of the reverse osmosis membrane efficiently remove bacteria, viruses, and parasites, ensuring that your water is free from waterborne diseases. However, it is advisable to combine RO systems with UV or activated carbon filters to provide an extra layer of protection against microorganisms.

      4. Chemical Contaminant Removal: Reverse osmosis is highly effective at eliminating chemical pollutants from water. It can remove pesticides, herbicides, industrial solvents, pharmaceuticals, and other harmful chemicals, ensuring your drinking water is clean and chemical-free.

      5. Sediment Filtration: RO systems have pre-filters that capture sediments and suspended particles, preventing them from reaching the RO membrane. This enhances the longevity and efficiency of the system while improving the taste and clarity of your drinking water.

The nominal rejection performance of Thin Film Composite (TFC) membranes for common contaminants is shown in the table below*. Please note that the following values are approximate and can vary depending on the specific membrane and operating conditions:

Inorganic Contaminant Nominal Rejection (%)
Aluminum 93–99%
Arsenic3+ 70–80%
Arsenic5+ 93–99%
Barium 93–99%
Bicarbonate 90–98%
Boron 55–80%
Cadmium 93–99%
Calcium 93–99%
Chloride 90–98%
Chromate 90–98%
Chromium 93–99%
Copper 93–99%
Cyanide 90–98%
Fluoride 90–98%
Iron 93–99%
Lead 93–99%
Magnesium 93–99%
Manganese 93–99%
Mercury 93–99%
Nickel 93–99%
Nitrate3 85–95%
Phosphate 93–99%
Potassium 90–98%
Radioactivity 93–99%
Selenium 93–99%
Silver 93–99%
Sodium 90–98%
Strontium 93–99%
Sulfate 93–99%
Zinc 93–99%

 

Biological and Particulate Contaminants Nominal Rejection (%)
Ameobic Cysts >99%
Asbestos >99%
Bacteria >99%
Giardia >99%
Organic molecules with a molecular weight >300 >99%
Protozoa >99%
Sediment/Turbidity >99%

* Source Water Quality Association Annual Education Kit Volume X – Article 4

This table shows the expected performance of Thin Film Composite (TFC) membranes used in drinking water systems. These systems typically operate at a net pressure of 60 psi (pounds per square inch) and a water temperature of 77°F. It's important to note that the actual performance of systems using these membranes may vary. Factors such as changes in feed pressure, temperature, water quality, contaminant levels, net pressure on the membrane, and individual membrane efficiency can impact the overall performance.

In general, countertop reverse osmosis (RO) drinking water systems tend to offer better rejection performance than undercounter systems. This is because countertop systems maximize the net pressure on the membrane, leading to improved overall results.

However, it's important to consider other factors as well. Iron and manganese, although effectively removed by the membrane, can easily deposit on its surface even at low concentrations, potentially causing fouling. It's advisable to remove iron and manganese using other water treatment methods before using RO.

The removal of nitrates depends on factors such as pH, temperature, net pressure across the membrane, and the presence of other contaminants.

While reverse osmosis membranes theoretically remove almost all microorganisms, including viruses, they may not offer absolute protection in consumer drinking water systems. Potential seal leaks and manufacturing imperfections could allow some microorganisms to pass into the treated water. Therefore, small home RO drinking water systems should not be solely relied upon to remove biological contamination for safe drinking water.

The rejection of organic molecules with a molecular weight (MW) less than 300 depends on their size and shape. To ensure complete removal of these lower molecular weight organic contaminants, activated carbon is always used in combination with reverse osmosis.

It's important to note that the values presented here represent approximate rejection rates and can vary depending on factors such as the specific membrane, operating conditions, feedwater quality, and system design. For accurate and up-to-date information on the performance of TFC membranes for various contaminants, it is recommended to consult the manufacturer's specifications or conduct specific tests on the membranes of interest.

Conclusion

Maintaining access to clean and safe drinking water is crucial for the well-being of individuals and communities. Reverse osmosis water treatment offers an effective solution for combating drinking water contaminants. By using this advanced filtration method, you can enjoy pure and healthy water, free from heavy metals, microorganisms, chemicals, and sediments.

Investing in a reverse osmosis water treatment system for your home or office will provide you with peace of mind, knowing that you and your loved ones are consuming water of the highest quality. Remember, when it comes to your health, having access to clean water should always be a top priority.

So, why compromise? Choose reverse osmosis and experience the benefits of pristine drinking water today!