Friday, September 14, 2018

Hebbagodi Lake Report

Hebbagodi Lake is on 38 acres and is located very close to Biocon Limited in Electronic City, Bangalore. We visited the lake on 29 May 2018, and gathered that although the lake falls under the jurisdiction of Hebbagodi City Municipal Corporation, it is maintained by Biocon Limited since 2016. There is no STP at the lake, but the pollutant load of raw sewage entering the lake is reduced by addition of a certain type of bacteria based enzymes. There is one raw sewage inlet entering the lake from SW direction, and an outlet in the NE of the lake. Apart from the main inlet, there are four storm water inlets and a few inlets from individual houses where raw sewage enters. Upstream of Hebbagodi is Thirupalya and Shikaripalya lakes. Also there is Veerasandra lake which joins Hebbagodi from the North. There are 400 floating wetlands in the lake which are placed at the edges of the lake and near the outlet.

Hebbagodi Lake series Map

Overview and Observations
Hebbagodi lake is located in Electronic City, Bangalore.

Lake Area
38 acres
No STP exists at the lake but bacteria based enzyme is added upstream of the lake to reduce the pollutant load of the sewage entering the lake from SE direction. Floating wetlands and aerators in the lake also help in maintaining the water quality in the lake.
There is a motorable road around the lake. About half of the lake perimeter is fenced. There exist a childrens play area and a plan to install benches around the lake. Many shrubs, flowering plants and about 300 trees are planted around the lake. There is one primary inlet through which the sewage from the SW direction. The only outlet from the lake is located in the NE. Although there are fishes in the lake, no commercial fishing takes place. There are three gates around the lake to prevent the cows coming in and grazing. There are five people who work at the lake to maintain it. The Lake
Only one inlet was identified from which sewage would enter Hebbagodi Lake. It is summarized below.
Sewage inflow
Partially treated sewage along with storm water enters the lake from SW direction. Upstream of the inlet is Thirupalya and Shikaripalya lakes. About 2 MLD of water enters into the lake.

The outlet from the lake is an overflow system in the NE of the lake.

No STP exists in the lake premises. However, a bacteria based enzyme provided by Jalavahini Management Systems added at various locations on the upstream side of the lake has helped in reducing the BOD levels from 250 ppm to 30-40 ppm near the outlets along with the reduction caused by wetland species. There are eight aerators to keep the DO levels in right amounts. Water quality is tested twice every month at Biocon labs and once a month at some external lab. The points of water sample collection are at the the inlet, centre and outlet.
The Wetlands
There are about 400 floating wetlands at the edges and near the outlet of the lake. These floating wetlands are tied to the edge of the lake bund. Also, There is no stone placed on the slopes of the lake to hold the sand. To control the erosion they have planted vetiver on the slopes whose roots grow deep and helps in holding the soil together and prevents erosion. Vettiver is also found  in the floating wetlands. Other wetland plant species are Canna, Colocasia, Nutgrass and Aligator Weed. The size of each floating wetland is about 4ft*8ft.

Contact Info:
Ashwin, Engineer, EHS, Biocon:8884501116
Naveen, JMS Biotech: 9964755220
Shashank, JMS Biotech: 9742415496

1 comment:

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