Treating Water

Context: The recent National Green Tribunal (NGT) has set a deadline for environment ministry to bar the use of Reverse Osmosis (RO) water purifies where the water conforms to quality standards. 

Arguments favouring the use the RO:

• Inadequacy of conventional cleansing treatment: which can have certain organic and inorganic residues and traces of heavy metal to make water unfit to drink. 

• • • This is often observed in mega cities and industrial towns.

• Necessity of use: in coastal areas where RO system is essentially used to make sea water or hard and saline under ground water potable.

Arguments against the use of RO:

• Wastage of water: It results in the wastage of 70-80% of water.

• A water stressed country like India can ill-afford to continue using RO. 
• Removal of essential nutrients and minerals: making it unhealthy and tasteless.
• In these cases, the commonly available UV (ultraviolet) and UF (ultra-filtration) systems of water refinement are deemed good enough.

Steps taken by NGT

• Banning the use of RO: in areas where the available water conforms to the prescribed quality norm of dissolved solids content of below 500 mg per litre.

• Directed mandatory recovery of at least 60% water from RO units.
• This would require the industry to make fresh investment in technology upgrade to build new and more efficient RO models capable of cutting down water wastage.