Wastewater Reuse – An Investment for the Future (Part 1)
Reading Time: 3 minutesWastewater is any water that has been contaminated by human use. It is the byproduct of domestic, industrial, commercial, or agricultural activities.
India generates sewage at an average rate of 61,754 million litres per day (MLD). Class I (city) and Class II (town) agglomerates contribute to 15,644 MLD sewage. Out of this, over 7,604 MLD water goes untreated.
The shortage of resources for water treatment is mainly because many of the established water supply projects in the country do not have an efficiently integrated wastewater collection and treatment system. We had abundant water resources once upon a time. Wastewater had no use and they were supposed to be disposed of.
We were forced to change this attitude towards wastewater in the past few decades. There are two reasons for this. First is the damage wastewater does to the environment. Second is the acute water shortage in the country.
Effects of wastewater on the environment
Untreated water often ends up in natural water bodies like lakes, rivers, and sea. This water has a high content of chemicals and other pollutants. It contaminates the natural water bodies, thereby destroying natural habitats like algae, aquatic plants, planktons, fish, amphibians, birds, and mammals associated with the water bodies.
A part of untreated water seeps into the groundwater table and pollutes them. This is the water that we draw from open wells and borewells. If this water is used in agriculture, the soil quality depletes. It will result in fewer agricultural yields at a slower rate.
Untreated water can result in health ailments among humans as well. In the year 2018, seven Indians died every day due to polluted water. At least 36,000 Indians were diagnosed every day with water-borne diseases. Acute diarrhoeal diseases (ADD), a common water-borne disease, accounted for 60% deaths among children below five years.
Extreme water shortage in India
The population is increasing at a rapid rate. Climate change is causing the drying up of natural water bodies. Groundwater is plummeting. The remaining water bodies got polluted due to the lack of effective policies to protect them. India is placed 13th among the 17 extremely water-stressed countries in the world. Water scarcity affects nearly 600 million people, almost half the population, each year.
India is projected to surpass China as the world’s most populated country by 2027. This will only worsen the water scarcity in the country.
How to reuse wastewater
The high rates of health and environmental degradation coupled with acute water shortage have gotten the government to rethink wastewater treatment as an important aspect of communities. Thanks to the advancement in technology, we now have the means to recycle and reuse wastewater.
Wastewater that is processed and reused is called reclaimed water or recycled water.
Reclaimed water is often cheaper than the standard pipe water supplied by local bodies. Therefore, it is a great replacement of groundwater for non-potable usage.
Below are some ways of reusing wastewater:
Domestic: Toilet flush, washing vehicles, garden irrigation, air conditioners, water sprays for dust control
Commercial: Golf courses and sports grounds irrigation, landscape irrigation, cleaning building floors and windows
Municipal: Public parks irrigation, cleaning streets, fire fighting, man-made water bodies for boating or aesthetic appeal
Industrial: Boiler feeds, cooling towers, cooling water, washing industrial equipment, cleaning factory floors and windows, water sprays for dust control
Agricultural: Field irrigation, washing farm equipment, water sprays for dust control
Other: Indirectly recharging groundwater through wetlands and marshes
Wastewater can even be treated to reach the standards of drinking water. Since May 2009, NASA has been recycling wastewater and urine in the International Space Station (ISS). The astronauts at the ISS use recycled water for drinking and food preparation. However, this advanced technology is expensive. So, it may not be an immediate possibility.
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