AAP government ropes in Israeli firm to clean-up Delhi's most polluting drain

There is some good news for Delhiites. The biggest and most polluting drain that falls into Yamuna is finally set for a major clean-up operation with help from Israel.

The Aam Aadmi Party government has roped in Middle East's famous firm-Ayala Water and Ecology Limited-to spruce up an 8-km stretch of the Supplementary drain that joins Najafgarh drain and finally falls into Yamuna.

The Supplementary drain, with a capacity of 180 million litres per day (MLD), begins from village Kakrola and is Najafgarh's biggest contributor. Delhi Water Minister Kapil Mishra said, "For now, we have decided to let Ayala work on an eight-kilometre stretch of the Supplementary from Bhalswa to Surghat only. They have been hired as a consultant after a thorough tendering process. Their mandate is to prepare a Detailed Project Report (DPR) looking into four polluting aspects of this drain: Sewage, Septic, Historical Sludge and Solid Waste."'

"After they submit a plan within four months, another tender will be floated to get an executing company," Mishra added.

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Importantly, Ayala is also working on Ganga rejuvenation under the Ministry of Water Resources (MoWR) at a stretch in Rishikesh, and on lakes in Hyderabad and Bengaluru.

Delhi has three major surface drains - Najafgarh plus Supplementary, Shahadra and Barapullah - of which the first is believed to be the filthiest. Najafgarh traverses a length of 40km from Dwarka to Wazirabad with a catchment area of 374sqkm. According to the Central Pollution Control Board (CPCB), almost 70 tributary drains join it and total 17,288 industries from across the Capital pour their effluents into it.

Apparently, all the major drains of Delhi have not undergone a comprehensive desilting and cleaning process since their inception. Delhi's drainage system was laid in 1976 by the Irrigation and Flood Department, taking into account the urbanisation limits up to 1981. IITDelhi, which was appointed by the Delhi government in 2012 to draw up a new drainage master plan, is still working on the project.

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Delhi Jal Board CEO Keshav Chandra said, "Ayala specialises in phytoremediation and constructive wetlands. This involves planting specific shrubs and trees, besides placing elements like gravels and limestone, which will absorb chemicals and pollutants from homes and factories. This will be an inexpensive, natural and benign method of cleaning the river."

"Besides, the floating and sedimentary sludge and solid waste will be collected and treated suitably so that it can be recycled in the form of bricks or biogas," he said. Identifying the area where such a huge amount of sludge can be deposited is an issue to be tackled, he added.

Ayala's CEO, Eli Cohen, recently said in an interview that in western countries such as USA, 36 per cent of the energy produced is used for sewage water treatment. This energy can be conserved if we use natural methods like plants.

DJB CEO Keshav Chandra said, "This cleaning, if successful, will be replicated in Delhi's other drains. We expect that Ayala's work will have a demonstrational effect. As Supplementary drain has a lot of open space around it, we hope that its sprucing up will attract visitors and make it a beautiful, green and recreational space."

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