Filtering out the dark side of drinking water

Over the past decade, water purifiers have become ubiquitous in Indian households. It is good news in a country where a majority of people are devoid of access to clean drinking water and water-borne diseases are a common occurrence. Among the available water purification technologies, reverse osmosis (RO) has emerged as a favourite across households and industries.

Originally used to make sea water potable, this technology is now being used to purify sources of drinking water. On the industrial front, RO systems are used to treat boiler feed water, industrial wastewater, process water and other such purposes. Bottled water brands also rely heavily on this technology. Although RO filters are equipped to remove toxic contaminants like arsenic and fluoride, its consequences on health and environment are often brushed under the carpet.

A recent study at Jawaharlal Nehru University shows that an RO purifier can waste 80% of raw water input.

The increasing usage of this technology is likely to worsen the country’s current water deficit. Another research on the viability of RO in water-stressed regions of India highlights that the concentration of pollutants in the reject water increases with increasing the recovery rate of purified water. While this reject water can be used for cleaning, most of it is usually drained out, further contaminating the groundwater.

Technological advancements have certainly proven to be a boon, but the long-term impact of such technologies must be carefully evaluated to ensure sustainability.

Despite its high cost and innate drawbacks, many organisations and governments continue to favour the installation of RO water systems in rural and urban areas.

There is a growing need for alternative technologies for water treatment that are resource efficient, yet effective.

One such example is Capacitive Deionisation that works on one fourth energy and wastes less than 20% input water as compared to RO systems. Additionally, municipal authorities, commercial and residential buildings must turn to central purification systems to provide drinking water through taps.

While new methods may involve relatively higher capital cost initially, the long-term cost incurred by individual households and its negative impact on the environment will drastically reduce. It is critical to make users aware and participate in revolutionising the access to clean drinking water. They must be empowered to make a choice that favours human health and environmental sustainability.