Tuesday, July 27, 2021

Strategic In-stream Systems” “STRAINS” at Soul Kere

In-Stream Decontamination system is a small-scale collaborative project constructed near the southern inlet of Soul Kere.  This intervention is part of an ongoing collaboration which includes diverse partners spanning Design, Engineering, Civil Society, and Science perspectives.  The six-fold partnership includes input from Biome Environmental Trust (project management, collaboration, coordination), MAPSAS (community engagement), Eco Paradigm (engineering and construction), Commonstudio (design), ATREE (monitoring), and Wipro (fiscal sponsorship).

This small scale intervention “model Nallah”, approximately 2M Wide and 8M long has been constructed next to the STP at Soul Kere.

Within this space, we will run a series of experiments with jelly stones and terracotta rubble materials. The first treatment will test the removal of organic contaminants by means of jelly and Terracotta rubble material. Terracotta has properties which makes it a viable biofilter media for urban wastewater. We plan to test the system for flows between 2.4 and 9.6 KLD.

The ultimate aim is to use the insights of the Sowl Kere studies to develop a series of larger interventions which can be placed directly within nallahs to prevent the contamination and eutrophication of urban lakes. We call this larger approach “Strategic In-stream Systems” or “STRAINS”— decentralized, frugal, flexible, and inclusive.

Progress Report


  • Evaluate the performance of STRAIN system with respect to materials(Gravel and Terracotta)

in treating wastewater

  • Optimize the design of STRAINS for efficient removal of contaminants

  • Develop an approach to enhance community participation and to hand over the maintenance of systems to the communities. This will help in promoting community engagement that will lead to a greater impact.

The project was implemented and monitored for a year. Please find detailed project report here


  • STRAINS showed good potential for dealing with highly variable influent quality. The removal efficiency was good for TSS and organic matter and satisfactory for nutrients in both setups. According to the results an average percentage removal of pollutants from the system was found as follows: TSS - 86% for gravel, 80% for terracotta; COD - 70% for gravel, 66% for terracotta; BOD - 80% for gravel, 79% for terracotta; TN – 13% for gravel,26% for terracotta; TP - 38% for gravel, 53% for terracotta

  • STRAINS showed similar performance for gravel and terracotta setup for total suspended solids and organic matter removal (p>0.05). According to the results terracotta showed better nutrient removal efficiency than gravel.

  • Higher organic loading rate of highly soluble effluent is decreasing the treatment performance of TSS, COD, BOD5, and nutrients. STRAINS achieved the better effluent quality when the system was loaded with COD ≤ 300g/m2/d. The corresponding removal efficiency observed in both gravel and terracotta setup was 69% and 50% respectively. Similarly, the optimum loading rate for BOD5 and TSS are found to be 44g/m2/d and 140g/m2/d respectively. At this optimum loading rate, the maximum removal efficiency of BOD5 recorded in gravel and terracotta setup was 80 and 83% respectively. Meanwhile, the TSS removal efficiency of gravel and terracotta setup was found to be 68 and 58% respectively.

  •  The pollutants (TSS, organic matter, nutrients and coliforms) removal efficiency of pollutants in the lower half (4 -8 m) of the system was higher than overall efficiency (0-8m). Increase in contaminants levels were observed at the center of both the systems. This could be attributed to breaking down contaminants into simpler form as greywater moves towards the centre of the system.

  • STRAIN system is a pilot system which is deployed  in the natural environment, with the construction activities going in the catchment, the quality of inflows to the system were highly variable which is interfering with the effluent quality. 

Nanjapura-Vabasandra-Kyalasanahalli Lakes

A Visit to Vabasandra, Nanjapura, Kyalasanahalli lakes  was done in February 2020 along with Mr. Anand Malligavad who has rejuvenated these lakes. All these lakes are located close to the Bommasandra Industrial area near Bangalore. The area adjacent to the lakes has agricultural fields, Layouts, Buildings and Factories.  His aim is to rejuvenate 45 lakes in 12 streams  by 2025.

Before rejuvenation the lakes were dry. Post rejuvenation all these lakes have water and the groundwater level has increased in the surrounding areas. The villagers adjacent to the lakes mentioned that Borewells and wells around the lakes have more water post rejuvenation

All Lakes have been funded for rejuvenation by different companies. 

Nanjapura, Vabasandra, Kyalasanahalli Lakes in Anekal Taluk

Nanjapura, Vabasandra, Kyalasanahalli Lakes

Nanjapura Lake:  18 acre lake was rejuvenated in 2020.

Nanjapura Lake PC: Anand Malligavad

Vabasandra Lake: A 9 acre lake was rejuvenated in 2019. Overflows into Kyalasanahalli Lake

Vabasandra Lake PC:Anand Malligavad

Kyalasanahalli Lake: A 36 acre lake, was rejuvenated in 2018.  

Kyalasanahalli Lake. PC: Anand Malligavad

Some observations on the design and features of the rejuvenated lakes

Details of desilting works that is carried out :

Desilting is carried out with help from local contractors.  No desilting is carried out for upto a distance of 50m from the bund. This is to ensure that no cracks or destabilisation of the bund happens as a result of the desilting work.   Increase in depth of the lake bottom is gradual from the perimeter to the central parts of the lake. Shallow Depths have been maintained near the perimeter of the lake to ensure safety of people who may walk in. Deep and shallow points also exist within the lake.  

Hadosiddapura Lake after desilting and bund work PC: Anand Malligavad


A ring bund is created around the lake. At Nanjapura lake the slope of the bund is 1:4 at the outlet side. The bund is not a single sloped surface but is made up of 3 terraces/steps.  Napier grass has been planted in the lowermost step. This was recommended by Tamilnadu University. Cattle herders come to collect this grass for their cows. It is said that cows prefer this grass.  Plants and trees such as Arjuna which can thrive even under submerged conditions have been planted on the middle step. Ficus and fruit trees are planted on the uppermost step. The thought is that these trees will provide shade and fruit to the birds and the community.

Stone pitching has been kept to the minimum - so as to avoid import of materials from outside the lake..

 In Nanjapura and Vabasandra the bund at the outlet side has the walking path which is 10ft wide. Walking path on the main bund has not been paved with paver blocks or any external material.  Mud and gravel are used to create this walking path. Walking path is created on only one side of the lake. Rest of the area is accessible only for maintenance with a very narrow path. This area also acts as conservation/biodiversity space.

Step bund Napier grass

The bund is raised above road level.  To walk from the road level to the bund, steps are provided. This is to ensure that vehicles do not ride on the bund and also prevents encroachment and garbage dumping.


Steps from the road leading to the bund  and  Walkway on the bund at Nanjapura lake

Inlets and Outlets

All drains leading to the lake and out of the lake have been cleaned. 

Instead of creating concrete silt traps, a deep pit has been created which serves as a silt trap at the inlets.  Here the silt settles down and water overflows into the lake. Trees and shrubs have been planted around it which prevent accidents and dumping of garbage into the pit.

This pit is emptied as and when required by Mr Anand along with the help from local neighbours of the lake  

Deep pit silt trap at Kyalasanahalli


Drain carrying wastewater into the lake  and Clear water after passing through the wetland at Vabasandra lake


At all major inlets a series of 3 to 4 settlement tanks have been built. Each tank is separated by a mud wall/bund  This is treated as a wetland.  Water passes through each tank and gets purified before it enters the next tank. There are openings provided in the center of the separation wall for water to flow from one tank to the next.  A path has been left for JCB to enter the wetland for maintenance. Some of the tanks/wetlands also act as Kalyani for idol immersion and other religious purposes.


Series of Wetland / Settlement tank at the inlet - Nanjapura Lake

In case of Vabasandra Lake it was observed that the wastewater drain from the village joins the lake after passing through the wetland. Wetland has alligator weed and knotweed which are growing naturally. No wetland species have been introduced. The water gets filtered here before it enters the lake. 

It was observed that the water entering the lake is of better quality. Many fish and some submerged  macrophytes were found growing in the lake.

Submerged macrophyte at Vabasandra lake         A Snake cooling itself in Vabasandra lake


Islands have been created in the lake using the mud from the lake.  Ficus, fruit and other trees have been planted on the island.  

Water Levels

Old concrete electricity poles with markings have been used as markers in the lakes. They have been placed at multiple places in the lake. These markers help calculate the volume of water in the lake at any given time. They also act as a safety feature so that people can be aware of the depth of water at a particular point and hence be  careful when they go into the deeper area.  

Monitoring the changes in water level by  observing the the marks made by water on the bund helps in understanding seasonal variations in water levels

Water Level markers in the lake

Lines observed on the bund due to evaporation

Devara Kadu - Miyawaki Forest

In some of the lakes two types of forest have been created.  One is the Miyawaki forest where the planting is very close. The other where the trees have been planted 10ft apart.

At Lakes which have space, Miyawaki forests have been created.  This is fenced using barbed wire and  bougainvillea.  Bougainvillea has been planted as this will act as a natural fence and can sustain with minimum maintenance. No one is allowed to enter the Miyawaki forest. 

Miyawaki Forest at Vabasandra lake


Before rejuvenation of the lake an agreement is made with the Panchayat that the lake should not be given for commercial fishing.  No net should be used for fishing at the lake.  Individuals can fish any amount at the lake using a rod. This helps the villagers to continue to use the lake for fishing.


There is no fence around the lake.  However, where required bougainvillea is planted which creates a natural fence.

Space for washing clothes

In some lakes where people use lake water to wash clothes, a space has been created with gradual slope for washing.

Women washing clothes at Kyalasanahalli Lake

Swimming at the Lake and Sign Boards

Swimming is allowed in the lakes.  Sign boards are placed around the lake with ‘Danger do not swim here’ in case there is danger in the area such as boulders etc.

Sign Board - Danger do not swim here


Benches are provided on the pathway on the bund. 

Benches on the walking path

Preserving old carved stone found at the lake

Old stone with the carving of a snake was found at Nanjapura lake.  It  has been installed at the lake bund. A platform has been created for people to worship it.

Preserving old inscription stone - Nanjapura lake

Lake maintenance :

A gardener is appointed to take care of the plants/trees in the lakes.

Anand Malligavad has a very close connection with the villagers at all the lakes he has been involved with.

Lake groups have been created at each lake.  This group  alerts/stops any unacceptable activities that are carried out in the lake area - like felling of trees, drinking, driving on the bund, cattle grazing on planted trees etc. With the help of the Lake Group / local community the activity is stopped immediately.

Cleaning the lake is done with volunteers from the village when required.

Contact Information

Anand Malligavad : m.anand161980@gmail.com 

Thursday, July 1, 2021

Biome Environmental Trust at the London Design Biennale

Biome Environmental Trust presented the 'Million Wells for Bengaluru' campaign as part of the India Pavilion at the London Design Biennale in June 2021. Curated by Nisha Mathew Ghosh, the India Pavilion had various other organizations and projects that present India's story to the world (and ourselves!) with a plea for a sustainable, ecological shift across domains, on the themes of forest, air, earth, energy, and water. Biome presented a detailed 4-page poster on the Million Wells campaign.