26-March-2024-Special-Article

REVERSE OSMOSIS

Reverse Osmosis (RO) water purification has gained widespread popularity due to its effectiveness in eliminating contaminants and reducing Total Dissolved Solids (TDS) levels in water.

However, concerns have emerged regarding the loss of essential minerals like calcium and magnesium during the RO process.

What is the RO Water Purification Method?

• RO is a water purification process that utilizes a semi-permeable membrane to remove impurities from water.
• Water is forced through the membrane under pressure, allowing water molecules to pass while blocking contaminants.
• This method effectively removes dissolved solids, chemicals, microorganisms, and other impurities, producing clean and purified water.

Reasons for Growing Demand for RO Water:

Poor Water Quality:

• Regions facing challenges with poor quality groundwater or tap water seek clean drinking water alternatives due to issues like brackish taste and contamination.

Perceived Health Benefits:

• Consumers believe that RO water is safer and healthier to drink compared to untreated water, contributing to its popularity.

Convenience and Accessibility:

• RO water is readily available through purification plants and domestic systems, offering convenience and ease of access.

Increasing Urbanization:

• Urban areas experiencing groundwater contamination and municipal water quality issues drive the demand for RO water purification systems.

What are the Concerns Related to the RO Process?

Loss of Essential Minerals:

• RO systems remove essential minerals like calcium and magnesium, potentially leading to micronutrient deficiencies and health issues.

Extreme Reduction in TDS Levels:

• Studies indicate significant reductions in TDS levels in RO water, resulting in a scarcity of essential minerals.

Health Impacts:

• Removal of beneficial minerals can contribute to health problems such as joint pain, heart disease, and magnesium deficiency.

Recommended TDS Limits for Safe Drinking Water:

Bureau of Indian Standards (BIS):

• Maximum TDS limit for safe drinking water: 500 mg/l (ppm); permissible limit: 2,000 mg/l.

World Health Organization (WHO):

• TDS in drinking water should range between 600 and 1,000 mg/l according to WHO standards.

International Standards:

• Countries like Europe, the US, and Canada set TDS standards at 500 to 600 mg/l.

Technologies to Address Mineral-Related Issues Within RO Systems:

TDS Controllers and Mineral Infusion Cartridges:

• To tackle TDS-related concerns, manufacturers of RO systems have introduced TDS controllers (or modulators) and mineral infusion cartridges (or mineralisers) for both commercial and residential units.
• TDS controllers assist in regulating TDS levels in purified water, while mineral cartridges incorporated within the system infuse targeted minerals into the water during the filtration process.
• Moreover, the decrease in TDS levels tends to lower the pH of water, resulting in increased acidity.
• Consequently, modern RO systems are equipped with alkaline cartridges to introduce compounds such as bicarbonates and hydrogen oxide into the water stream.

Way Forward:

Assessment of Water Needs:

• Emphasis should be on assessing regional water conditions to determine the necessity of RO systems.

Alternative Technologies:

• Alternative purification technologies should be considered based on specific contaminant concerns in different regions.

Local Authority Responsibility:

• Local authorities must ensure that water supplied meets BIS standards, especially in areas prone to contamination.

Mains Question:

1. Explain the Reverse Osmosis (RO) water purification method and discuss the concerns associated with it. What measures can be taken to address these concerns and ensure safe drinking water for all? (150 WORDS)