Huge amount of sewage flows from Bellandur Lake to Varthur Lake due to the failure of Bangalore Water Supply and Sewerage Board (BWSSB) to manage the sewage of the city. Bellandur, along with Varthur—the other major lake in Bengaluru— has been ruined because of the constant dumping of untreated sewage and toxic chemicals from small factories. The BWSSB has certainly failed to divert sewage water.
Illegal dumping of garbage on the banks of the lake is a persistent issue, the locals allege that weeds and dry grass are also regularly burnt in the area without supervision by garbage collectors.
Nearly 5,000 soldiers swung into action yesterday after the fire threatened a military area with huge clouds of smoke billowing from the lake filled with sewage, chemical effluents and construction debris and choked with water hyacinth, an army statement said.
In 2015, a toxic froth spilled over to some of Bangalore’s streets due to extreme levels of pollution in the Bellandur Lake. Tests found extremely high amounts of phosphorous and other inorganic chemical compounds in the lake.
The following key actions were identified:
Part-1: Restoration of lakes
- Remove encroachments from lakes
- In case of some lakes, incoming sewage is bypassed downstream. Correct these instances.
Set up small STPs to treat it locally.
- Currently the barrage design at Bellandur lake does not have gates, which allows accumulation of stagnated dirty water. Set up slew gates to let off stagnated dirty water.
- Desilt the lakes to increase the capacity and also to eliminate fires that feed on methane in peat layer.
- Identify areas for wetlands.
- Each lake needs wetland of specific size, depending on quality and quantity of the incoming sewage
- Construct wetlands of required size.
- Harvest the macrophytes from constructed wetlands to maintain their assimilative capacity at its peak
- Install aerators and fountains to ensure dissolved oxygen.
Part-2: Preventing untreated sewage ingress in lakes
- The Chairman of BWSSB made a commitment that 80% of the sewage entering the Bellandur lake will be treated by the end of February 2018.
- He also assured us that BWSSB would make the sewage treatment data available online, to prove that all STPs are fully functional.
- Government will set up a Sewage Treatment Plant at the Central Jail in Parappana Agrahara, thus saving the chain of five lakes.
Part-3: Preventing solid waste dumping in lakes
- Evict the illegal settlements in lake beds who segregate waste and set fire to rejected waste.
- Complete fencing around the lake
- Set up a full-fledged solid-waste management program
- Define waste-collection routes and collection frequency for all types of waste
- Mark all official vehicles with the route numbers
- Geofence all official vehicles
- Do strict fleet management of all official vehicles
- Impound all spurious vehicles used for dumping
- Metro generates a huge amount of debris while erecting pillars.
Suggestion was made to use prefab sections, which can be stacked to conduct load-test for sink-holes. The stack can be disassembled and used for the next location. This will eliminate a lot of Construction and Demolition waste.
- Medical waste from clinics and hospitals is found around lakes. Investigate this.
- Appoint lake wardens
(citizen watch committees empowered to monitor lakes, wetlands and STPs in the area)
The timeline for most of these actions is set as “immediate” or before next quarter.