Water which is the basic source of survival on this planet earth has presently become a scarce resource that is not available to the majority of the people easily. The world’s second most populous country (India) is running out of water. A total of 21 major Indian cities are expected to run out of groundwater by 2020, according to a 2018 report by NITI Aayog. By 2030, 40% of India would have no access to groundwater or drinking water. More than half of India is suffering from drought conditions. Recently, Chennai which is a coastal city and capital of Tamil Nadu went dry and water is being transported through goods wagons daily. Puzhal lake which is the main source of water for the people of Chennai has dried up. The water reservoir of Chennai is limited to 0.2% of water only. A private water tanker which costs Rs 1500 in 2018, now costs Rs 6000 in 2019. In the future, the fight for water is only expected to escalate.
Why Water Crisis?
Humans are squarely responsible for this state of affairs. Problems occur due to climate change. Winters are becoming more colder and summers hotter. The duration of Monsoon is reducing and rain occurs with more intensity due to which floods occur during rain and drought occur in absence of it. Environment destruction is also one of the major causes. Due to overpopulation & industrialization, rapid urbanization has pushed up demand for water. The release of industrial and domestic waste, including urban sewage into rivers, lakes has resulted in the pollution of freshwater sources at an alarming rate in India. Excessive usage of fertilizers, sewage water, and aquaculture lead to eutrophication.
What can be done?
The management of water crises needs to be tackled with some innovative approaches. One of the many is to recycle used water on the lines of Singapore.
- Solar Panels Water Purification Technique – Saudi Arabia’s King Abdullah University of Science & Technology researchers have invented a technique to utilize the energy generated from Solar panels to purify water. According to the researchers, solar panels convert only 20% of the light they absorb into electricity & the remaining 80% is released into the air. So, a system is being designed that can use this waste heat to generate fresh, clean water. The system is made up of a three-layer distillation system attached to the underside of the solar panel. It includes a stack of water channels separated by hydrophobic membranes & heat conduction layers. Waste heat from the solar panel is transferred to the uppermost layer of the system, where it evaporates seawater / contaminated water. The vapor passes through the porous membrane to the second layer, where it condenses as freshwater. The energy is being recycled again as the heat obtained during the condensation process passes through a thermal conduction layer. Water obtained would be safe to drink and can be used for daily consumption. In this system, co-generation of electricity and fresh water is taking place simultaneously.
- Solar Water Disinfection (SODIS) – Contaminated water can be treated by solar radiation treatment & water distillation with the additional use of solar heating. Solar water disinfection technique is only fruitful to disinfect small quantities of low turbidity for microbiologically contaminated water (such as seawater with high turbidity and water contaminated by heavy metal or pathogens), a solar-heated still is added to the system.
- For Low Turbidity Water – In this, the contaminated water is to be kept in clean, transparent Polyethylene Terephthalate (PET)bottles and allowed to place in sunlight basically at the roof of the house for at least 6 hours depending upon the intensity of sunlight. UV-A radiation interacts with DNA, nucleic acids & enzymes of the organic cells, leads to cell deaths. UV-A radiation also reacts with oxygen dissolved in water producing highly reactive forms of oxygen that can help the germicidal process. Infrared radiation is responsible for raising the fluid temp. 99.9% of microorganisms in the water are eliminated if the water is heated to 50-60 deg C for 1hour. The efficiency can be improved by exposing the contaminated water to additional reflecting surfaces such as aluminum sheets etc.
This article is written by “Shreesh Misra” ([email protected])