Explanation:

All the statements are correct.
The Floating Treatment Wetland (FTW) was inaugurated on World Wetlands Day (February 2) in Neknampur Lake in Hyderabad to clean and purify the polluted water body.
Plants planted on FTW can clean the lake by absorbing nitrates and other pollutants in the water.
About Floating Treatment Wetland (FTW)
• FTW is joint effort of NGO Dhruvansh, Hyderabad Metropolitan Development Authority (HMDA), district administration and other organisations.
• It measures around 3,000 sq. ft and comprises four layers viz. floatable bamboo at base, Styrofoam cubicles above it.
• The third layer consists of gunny bags and gravels on final layer to support cleaning agents (plants).
• Cleaning agents planted on FTW include vetivers, cattalis, canna, bulrush, citronella, hibiscus, fountain grass, flowering herbs, tulsi and ashvagandha.
• FTW’s working is based on soil-less hydroponics technique. Hydroponics permits plants to grow only on sunlight and water.
• There is no need of soil.
• There are small holes at bottom of base which facilitates flow of nutrients from water to plants through biological uptake process.
• Micro-organisms growing on FTW and plant root systems of cleaning agents break down and consume organic matter in water through microbial decomposition.
• The root systems filter out sediments and pollutants, reduce content of these chemicals from water body