1 MLD DEWATs at Mahadevpura Lake, Bangalore


Scale of service


Area of installation (Sq-m)

700 Sq-m

Year of Installation

January, 2019

Capital Cost

Rs. 1.25 Crores


Mahadevpura Lake, Bangalore

Operational & Maintenance cost


Funding Agency

CSR Contribution

Design Capacity

     1 MLD

Mahadevapura Lake is located along the outer ring road, Bangalore. The Lake is spread across an area of 26 acres. There are two wetlands, one in the southeast and the other in the northeast of the lake. In the lake, there are 4 inlets and 1 outlet. Of the 4 inlets, 3 overflows into the lake during any flood event and one enters directly into the wetland area that is to the southeast side of the lake.

In an effort to rejuvenate the lake, in 2016, The Bruhat Bengaluru Mahanagara Palike (BBMP) built necessary hydraulic structures to divert wastewater entering from the lake. To take these efforts further, United Way of Bangalore brought together tech firms (Amazon, Mphasis, Dell Technologies, HTC Global and BORDA), to fund a complete solution for the lake, as part of their CSR. CDD provided the technical guidance while the construction was led by Revlon Build Tech.

The STP taps and treats 1MLD wastewater flowing in an adjoining drain and discharges it into the lake. This ensures that the lake receives water throughout the year apart from aiding in ground water recharge, enhancing micro-climate benefits in the area and improving urban aesthetics.


DEWAT is a chemical free process with minimum dependence on electricity for treating the wastewater. It is an anaerobic process that aims to mimic natural processes by providing the right conditions for microbial action.

The wastewater treatment includes primary, secondary and tertiary treatment process, chosen and combined in order to handle the pollution load entering through the selected inlet drain. It also has been designed with aim of very low Operation and Maintenance requirements.

Preliminary treatment - Screen with grit collection structure with gate for wastewater diversion

Primary treatment - Diversion channel with two stages of screening, sedimentation basin and balancing tank

Secondary treatment - Integrated Anaerobic Baffled Reactor (ABR) with Anaerobic Filters (AF)

Tertiary treatment - Combination of gabions followed by floating wetlands (includes wetland plants – Canna Indica, Cyperus, Papyrus and Vetiver) 


Regular maintenance includes cleaning and clearing solid waste from the screens, and regular operation of pumping of wastewater from balancing tank. Removal of sludge from the different modules is done once in 2-3 years. Filter media is replaced once in 5 years or depending on the condition. Plants in the floating wetlands are trimmed once in 4-6 months.


The treated water is reused to ensure that the lake receives the water throughout the year. The system can handle influent wastewater of quality up to 200 mg/l BOD and 400 mg/l COD; the effluent quality of BOD is 20-30 mg/l.


CDD Society, Bangalore
Mobile No   :  +91 8028486700                                  
Email Id        :   bangalore@cddindia.org                                
Address        :   Survey No.205 (Opp. Beedi Workers Colony),
Kommaghatta Road, Bandemath, Kengeri Satellite Town,
Bangalore 560 060, Karnataka, India
Website       :   www.cddindia.org