One of the major consequences of rapid urbanisation has been the water crisis looming over major cities of the country. Owing to the increased dependency of these cities on groundwater, their water resources have depleted, leaving them at the mercy of rainfall. There is a huge gap between water demand and supply. To bridge this gap, innovative solutions need to be developed. A number of companies have come up with technologies to make water suitable for potable purposes through tertiary treatment and desalination processes.
A company, MaithriAquatech, has developed one such technology that converts air into water. The device, Meghdoot, is a low-cost atmospheric water generator that uses the condensation technique to make potable water from the atmosphere. It sucks air into the system through an electrostatic filter. Condensation takes place when cooled coils in the air path provide a temperature differential between the air and the coil surface. The water then passes through various filters that remove solids, odour and bacterial contents. The final water produced is treated with ozone as a preventive measure.
The device is equipped with two air filters of 12 microns and 1 micron to remove particles suspended in the air. This entire process of converting air into water is environment friendly and it does not generate any wastewater as in the case of the reverse osmosis process. The intricate filtration system in the device removes the odour and the collected moisture of all contaminants. Meghdoot produces 100 per cent microbe-free potable water. It consumes low power, requires minimum maintenance and works in a wide variety of temperature and humidity conditions, in the range of 20-45 degrees Celsius and a relative humidity of 30-100 per cent. It is an ideal solution to meet the water requirements of offices, airports, hospitals, hostels and residential complexes.
Case study: Indian Railways
The air-to-water technology has been deployed successfully by Indian Railways. In December 2019, South Central Railway (SCR) installed the atmospheric water generator kiosk at the Secunderabad railway station in a first-of-its-kind initiative. The kiosk produces around 1,000 litres per day of water directly from air, and this water is further filtered and remineralised. The water produced at the kiosk also meets the World Health Organization standards for safe and healthy drinking water.
SCR has set up the kiosk as part of its green initiatives and water conservation measures. It provides drinking water facility to passengers at a price ranging from Rs 2 to Rs 8. The cost of bottled drinking water is Rs 8 per litre, and if passengers carry their own filling bottle it costs Rs 5 per litre. Further, SCR is charging Rs 3 for 300 millilitres (ml) of water with a container and Rs 2 if passengers are carrying their own glasses. Similarly, the cost of a 500 ml glass of water is Rs 5 with container and Rs 3 without container.
In a recent development, in February 2020, TERI and MaithriAquatech signed an MoU to work towards providing universal access to drinking water through air-to-water technology. The decision is expected to promote the use of this technology in India. According to TERI, the prospective use of Maithri’s technology will be assessed based on its ability to provide equitable access to water and a piped water connection to every rural household by 2024 under the JalJeevan Mission, in order to meet the sustainable development goal. Under the MoU, TERI will conduct suitability and adaptability studies of the technology under different climatic conditions. Once the feasibility is tested, it plans to raise awareness about the technology through various stakeholders such as government ministries, state governments and other agencies.
The abundant availability of moisture in air presents a huge potential for converting it into water and provides an opportunity to stakeholders to invest in the innovative technique. The air-to-water technology has gained traction both in India as well as internationally. It is believed to have the potential to make households quasi-independent for water requirements and bring an end to the persistent water crisis. Moreover, it can be an efficient way to serve the communities in remote areas with scarce water resources.