Cleaning lakes the 'green' way

 Bangalore University’s Department of Environmental Science has claimed that it has developed a “green” method to clean up nearly 90 per cent of all pollutants in the City’s lakes.

Scientists at the department explained that their project, titled the ‘Green and eco-friendly technology for treating waste water entering into wet lands of urban Bangalore,’ aims at resuscitating all polluted lakes and water bodies in the City. They added that their system was superior to the existing method used by the government, which boasts of only 50 per cent efficiency.

Speaking to Deccan Herald, BU Environmental Science Head of the Department, Prof N Nandini, explained that the secret behind the project was a mechanism called ‘Phytoremediation’. “Cultivated algae such as Chlorella and Chlamydomonas and microbial bacteria will be used to absorb pollutants, including heavy metals,” she said. “Plants like Typha (a type of grass) and Water Hyacinths will also be used in the process.”

According to Nandini, the existing methods of purification adopted by the government are unable to treat nitrates, phosphates and oils in the water.
“The current method just removes a fraction of the pollutants,” she said and blamed soaps and detergents for phosphate concentration in water. “Phosphate, combined with sewage, chokes the water,” she added.

“A majority of lakes in the City are thus victims of ‘Eutrofication’ — a process by which a water body acquires a high concentration of nutrients and phosphates, which in turn, promote excessive algae growth, which depletes the oxygen content of the water, killing off organisms such as fish.”

Nandini explained that the primary step in treating polluted water was to interrupt the process of Eutrofication. “Getting rid of phosphates and nitrogen is fundamentally important for the efficient treatment of waste water,” she said.

Funding

This project is being funded by the University Grants Commission (UGC) with an allocation of nearly Rs 10.90 lakh. Started in April, the project is expected to last for three years and will also be used in water-treatment plants.

Prior to the method’s employment in the field, the department tested the pilot system in laboratory conditions. “The method will now be tested in a medium-scale environment before recommendations are made to the government for its implementation in water-treatment plants in Bangalore,” Nandini said.

The department plans to start operational testing by implementing the method at an apartment complex in the City.

In addition, it also plans to develop a more efficient way to handle waste water and solid wastes in the City by using activated charcoal extracted from the solid waste to absorb pollutants. Researchers also expressed their intention to clear the environment around the lakes, which have developed a stench because of accumulated pollutants.