Steps to revive south Delhi lake underway: DPCC to NGT

DDA has manually removed the algae from the lake and operationsalised the adjacent sewage treatment plant, NGT was told

The Delhi Pollution Control Committee (DPCC) has informed the National Green Tribunal (NGT) that corrective action to revive Satpula Lake near Khirki village, south Delhi has been initiated by the Delhi Development Authority (DDA), months after it found that the water body was suffering from high algal bloom.

Satpula Lake at Khirki village in New Delhi on Sunday. (Sanchit Khanna/HT Photo)

In a report to the tribunal on December 13, DPCC said that DDA — the land-owning body — has manually removed the algae from the lake and operationsalised the adjacent sewage treatment plant (STP). DDA has also carried out bio-remediation by introducing carp fishes, it said. DPCC said that a fresh water sample of the lake has been collected and results are awaited.

“The carp fishes are now one inch long, indicating that dissolved oxygen is high,” DPCC told NGT, according to the report.

When HT visited the lake on Sunday, it found no algal bloom in the middle but algae could still be observed in the periphery of the lake.

NGT in April took suo motu cognizance of a news report that said sewage water was being pumped into the lake from a large drain from the neighbouring Khirki village, and directed DPCC to furnish factual information. DPCC in May carried out an inspection and submitted a report in September saying that the lake was “highly eutrophic” and required attention.

Eutrophic water bodies are those that exhibit high algal bloom due to the presence of nutrients such as nitrogen and phosphorous in large water quantities, a by-product of sewage. DPCC also found that the STP in the area was non-functional.

In its latest submission, DPCC said it collected fresh samples of the STP and the lake on November 28, finding dissolved oxygen to be zero and ammonical nitrogen very high.

“A meeting with DDA officials was called on December 11. DDA in a reply on December 12 said that during the monsoon, there was excess surface run-off in the lake to the extent that an overflow arrangement had to be made. DDA observed that the run-off was mixing with sewage from Khirki, leading to pollution of the lake,” said DPCC. DDA also said that the STP has been operational since October 1 with algae manually removed and bio-remediation carried out, according to DPCC.

Diwan Singh, an activist who has worked on reviving water bodies in Dwarka, said sewage entering water bodies remains one of the biggest concerns in the Capital. “We have observed this in Dwarka, too. Until stormwater drains are protected and kept sewage free, we will not see water bodies staying clean. The fact that sewage is still not being trapped and sent to sewage treatment plants is also a key concern,” he said.