RE for RO Water: WWF

Using Renewable Energy for Fail-safe Drinking Water for Disaster-prone Areas

The Problem

The Sundarbans lie on the delta created by Rivers Ganga, Meghna and Brahmaputra. The Sundarbans is susceptible to high-intensity weather events, like cyclones, and their resultant impacts like storm-surge-induced floods, embankment breaching and saline water intrusion. In the past five years, three cyclones namely Bulbul (2019), Amphan (2020) and Yaas (2021) have occurred. On a 4-level cyclone intensity scale developed by India Meteorological Department (IMD), the three cyclones fall in the category of severe and above. Cyclones and its resultant effects have devastating impacts on the lives of the terrain’s inhabitants. It does not just lead to insecurity of lives, livelihoods and assets but also everyday needs and necessities, including clean drinking water. Saline water intrusion causes contamination of groundwater and deprives inhabitants of access to clean drinking water. It also disrupts government welfare schemes like Har Ghar Jal Yojana, a scheme that ensures assured delivery of potable tap water to homes and schools. The 46 forest-fringe villages being the last before forests begin, service delivery too is always the last. In view of the challenges of forest-fringe inhabitants, WWF-India decided to set up community-managed Reverse Osmosis (RO) water units, with energy and water autonomy, in Gosaba forest-fringe block.

A Potential Solution

A 20.47kWp Solar PV-powered RO drinking water plant has been operational since October 2023 in Rajatjubilee hamlet, Lahiripur gram panchayat, Gosaba. The RO water unit can deliver five litres of purified water per capita per day. The filtration unit can serve around 100 households.

To protect the unit from damage at the time of high-intensity weather events, module mounting structures have been designed to withstand wind speeds of up to 180 kmph. The plant can function for three days even in the absence of sunshine. A 25,000-litre raw water tank has also been constructed. The stored raw water ensures water autonomy for three days in times of crisis.

Before the distribution of water from the units, the quality of water was tested by an accredited water testing lab.

To ensure financial sustainability, the RO water unit is run as a community enterprise. The enterprise sells potable water through a subscription model. This ensures that the sponsor of the RO filtration unit, be it the state or a philanthropist, pays just the capital cost of installation while the managing entity picks up revenue expenditure.

The Impact

In the future, purified water, across all hazard-prone areas, can be ensured by adopting the community enterprise model. If capital expenditure is borne by either the state or philanthropies and operational expenditure by the community enterprise, the sustainability of purified water systems can be ensured.

This intervention can become a successful model across all hazard-prone areas of the country. By providing clean drinking water to communities, the intervention has the potential to reduce the vulnerability of all inhabitants of hazard-prone areas.