Icrisat develops constructed wetlands, a new technique to treat sewage in Telangana
By V Nilesh | Express News Service | Published: 20th January 2018 01:53 AM |
HYDERABAD: With booming population and burgeoning urbanisation, the water bodies are become increasingly filthy and unfit for human utilisation. Lakes and rivers are turning into giant gutters carrying waste and sewage. To provide a solution to this problem, the International Crops Research Institute for the Semi-Arid Tropics (Icrisat) has been working on a new concept called Constructed Wetlands (CW).
The project, researchers say, will greatly help improve the quality of water bodies that are currently being choked by gallons of untreated sewage disposed into them. In the highly-developed Hyderabad itself, only 50 per cent of the whopping 1,450 million litres of sewage generated every day is treated at STPs. Most of the untreated sewage is let out into water bodies -- mostly into Musi River.
The situation, needless to say, is worse in rest of the State compared to the capital city. Almost none of the 73 urban local bodies in Telangana, and more than 8,600 gram panchayats, have STPs. The result is sewage mixing with water bodies on an everyday basis, affecting surface water, groundwater, aquatic life,
Now, Icrisat, as part of an India-European Union project to treat sewage water, has developed around 30 constructed wetlands across the country, including three in Telangana. Researches have shown that a properly designed ‘constructed wetland’ can reduce pollution causing substances.
Solution to water crisis
“Currently, waste water is also being used for agricultural purpose which is dangerous,” says Suhas P Wani, Icrisat’s Asia research programme director. Wani adds that these wetlands can be created on open lands and near lakes that have illegal sewage outflows. The constructed wetlands requires a 1-meter deep pit measuring 20 meters in length and breadth each and a tank of similar measurement to store treated water.
What are constructed wetlands?
Constructed wetlands are made by digging up a portion of earth in which gravel, sand, mud are added in layers and are topped with plants. Few selective plant species, known for their ability to absorb pollutants, are used. The process involves collection of sewage in the wetland before reaching the water bodies. It’s then treated using natural filters like sand, gravel, pebbles and plants to remove the impurities. It takes three days for polluted water to get filtered and leave the wetland so that process is effective.