Monday, April 1, 2024

Biome with the CSE team on a National learning cum exposure visit to Bengaluru

As a part of the “National Learning cum Exposure Visit to Bengaluru”, organized by the Centre for Science and Environment (CSE), a team of 15 participants visited Bengaluru to learn about the best practices on used water management and lake rejuvenation in Bengaluru. This exposure tour was in collaboration with CDD (Consortium for DEWATS Dissemination India) India and Biome Environmental Trust.

Date and Time - 19th January 2024, 10 AM to 4 PM

Places Visited - Jakkur lake, Devanahalli WTP, Sihineeru kere

Biome team members - Avinash, Shivanand, Apeksha, Rajani, Eshwarappa

CSE team members - Harsh Yadav, Manish Mishra and others

On the second day of the CSE team's exposure tour, the Biome team joined them.

1. Rejuvenation of Jakkur lake by re-using the treated wastewater from STP :

        Jakkur Lake in Bengaluru is spread across a 160-acre area and is 200 years old. The rejuvenation story of Jakkur Lake is ideal for Bengaluru which has a major sewage treatment problem. Currently, an STP that treats the sewage to the secondary level (sewage treatment plant), and a constructed wetland are integrated with the lake. The STP has a capacity of 10 MLD (million litres per day). Treated wastewater from the STP is released into the wetland and then into the lake. The model is natural and self-sustainable.

        Mr Manjunath and Ms Meghana, Assistant Engineers from BWSSB joined us to explain the working of the STP. They explained that the sewage undergoes various types of treatment, including mechanical, biological, aerobic and anaerobic, after which the COD and BOD of the water are significantly reduced. The treated water is then passed through a chlorination tank for further improvement in the quality. This secondary treated water is passed through a constructed wetland consisting of aquatic plants and an algal pond, which reduces the nitrogen content by 40% and phosphorous content by 30%. The water is then let into the lake.
        The lake is clean and supports natural ecosystems - birds and trees and other flora and fauna. The groundwater table around the area has improved since the rejuvenation of the lake. A separate Kalyani is maintained to immerse idols of Ganesha. Fishing is a population occupation.
        After the technical discussion, we were told about  the community's involvement in maintaining the lake. Mr. Madhusudan from Jalaposhan - a citizen-led group that manages the lake,  explained the various activities conducted at the lake premises. He explained how the entire lake area is divided into a conservation zone ( the wetland ) and a community zone ( walking tracks, gardens, etc). They also conduct weekly programs like Shramadaan to involve citizens around the lake in its maintenance, educational tours for students, awareness programs, and programs to build community support. 

2. Integrating shallow aquifers into the water supply system in Devanahalli: 
        We then headed towards a small town, Devanahalli, located to the north of Bengaluru (rural) district, to understand the traditional sources of water supply like lake (kere) and wells (baavi). Devanahalli hosts a lot of wells and a lake called Sihineeru Kere. 

        Shivanand and Avinash from the Biome team explained the HN Valley project (Hebbal-Nagawara project). The Sihineerukere in Devanahalli receives secondary treated domestic wastewater from Bengaluru through the HN Valley project. As a result, the groundwater table in the region has improved over time and the wells around the lake have shown increased water levels. The Biome team has revived a well next to the lake. Two filter borewells have been dug nearby to augment the water supply. As a result, around 2.5 lakh L of water is extracted through these sources and passed through a WTP (Water Treatment Plant) that is set up next to the lake. This water is supplied to the town of Devanahalli, and people use it for day-to-day activities (except for drinking and cooking - for which water from local RO plants is used). The case study of Devanahalli is the best example of reusing treated wastewater for lake rejuvenation and shallow aquifer recharge.

Key Learnings:    

        In recent times, a shift has been observed in the understanding of the decision-makers and technically-minded society towards nature-based and decentralized solutions for wastewater management and lake rejuvenation. Bengaluru city is one such example where used water management has been understood holistically and dynamically. Further, it should be noted that the city administration and civil society are creating an enabling environment by saving, reusing, and treating every drop of water, whether waste or freshwater.

The day concluded with the CSE team with many learnings and knowledge exchanges. Blog written by, Apeksha

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