3 killed as under-construction water tank collapses

The roof of an under-construction biodigester collapsed at a BWSSB Sewage Treatment Plant (STP) in northeastern Bengaluru on Monday, killing two site engineers and a supervisor and wounding 20 other workers.

A biodigester is nothing but a tank which digests organic material biologically.

The Bangalore Water Supply and Sewerage Board (BWSSB) is building a 100 MLD STP on 25 acres of land at Jogappa Layout, opposite Lumbini Gardens in Hebbal, at a cost of Rs 360.77 crore. It awarded the contract to Surat-based Enviro Control Associates India Pvt Ltd in July 2017 while the project is being supervised by NJS Engineers India Pvt Ltd, a consultancy. Enviro engaged SMC Infrastructures for civil work as its sub-contractor.

The project is to be completed on January 30, 2020. Hundreds of workers from Kolkata, Bihar and Chennai have been working at the site.

The project involves constructing four biodigesters that would digest biosolids and produce gas. The roof of one biodigester has already been constructed. As much as 65.5 cubic meters of concrete was being poured on the roof of the fourth biodigester.

Work began at 5 am

The work of pouring the concrete on the roof of the biodigester began at 5 am on Monday and workers completed nearly 95% of the task in the next six hours. Around 11 am, the roof collapsed suddenly as the scaffolding below the shuttering place (formwork) gave away. The wet concrete, along with the scaffolding, came apart. Workers stationed atop also plunged down, trapping their colleagues working on the ground.

Two site engineers — Prabhu Rao, 29, and Krishna Yadav, 26, — and Sumanthkar, 22, a site supervisor, died before they could be taken to a hospital. All of them worked for SMC Infrastructures.

SMC Infrastructures had deployed three site engineers, two site supervisors and 15 labourers while Enviro Control Associates had posted an engineer. NJS Engineers India had deployed two engineers. All of them were evacuated and rushed to private hospitals.

Rescue operations

Fire and emergency services personnel, along with a team of the National Disaster Rescue, carried out the rescue operations. Within two hours, all the 20 injured were evacuated and the scaffolding was cleared.

BWSSB Chairman Tushar Girinath supervised the rescue operations while Rural Development and Panchayath Raj Minister Krishan Byre Gowda, Hebbal MLA Byrathi Suresh and Additional Commissioner of Police (East) Seemanth Kumar Singh visited the spot.

The jurisdictional Amruthahalli police have opened a case under IPC section 304 (A) (accidental death due to negligence) against the contractor.