On World Environment Day, a researcher writes how treated wastewater from apartment sewage treatment plants is used to maintain a lush-green public space.

A group of people gardening on a barren land
Voices World Environment Day Sunday, June 05, 2022 - 11:27

Flowering trees such as gulmohar and yellow oleander; fruit trees such as badam, jamun and papaya; and a thriving vegetable garden now stand at a site that was a garbage dump not too long ago. Around 9,500 sq mts of public land in a residential neighbourhood in Mahadevapura, to the east of Bengaluru, was unusable, and polluted by construction debris posing a hazard to the people who lived here until an incredible transformation began here in 2019, spearheaded by the residents themselves.

Tales of civic engagement, particularly in terms of tree-planting drives, are not uncommon in Bengaluru. But what makes Spark Tree Park stand out as a good example is the use of treated waste water from apartment sewage treatment plants to maintain the now lush ecosystem in this public space.

Wastewater as a resource

Residents from three apartments in the vicinity – Greens Apartments, Adithya Elixir and New Heaven – came together not only to revive a public space. The residents, along with the support of the then MLA Aravind Limbavali and the local BBMP corporator, sought to proactively restore it using treated wastewater from their apartments, thereby reducing the impact on freshwater sources and stemming the flow of wastewater into stormwater drains. Both these benefits are critically important in a rapidly urbanising city like Bengaluru that needs to urgently adapt to climate change.

This park is one of the sites that researchers from the Centre for Social and Environmental Innovation (CSEI) at Ashoka Trust for Research in Ecology and the Environment (ATREE) visited as part of our study to understand why treated wastewater was going unused in Bengaluru despite the mandate that apartments with more than 20 units have to install decentralised STPs and adhere to the Zero Liquid Discharge (ZLD) policy. 

Apart from reuse within the apartment complex itself, treated wastewater can also be used for non-potable activities such as construction and industrial usage as well as for greening public spaces—just like Spark Tree Park. There’s an opportunity here to effectively reuse treated wastewater and cut down on the use of freshwater. So, how did residents do this? And can this model be scaled across the city?

Carrot and stick

The ‘stick’ came in the form of the Karnataka State Pollution Control Board (KSPCB), which levied fines on these apartments five years ago as they were not adhering to dual plumbing and water quality mandates. They fixed their sewage treatment plants (STP) to ensure that their treated wastewater was meeting the quality norms prescribed by the KSPCB. But they were still struggling with excess wastewater as they could not possibly reuse all the water within the apartment fence for limited non-potable uses such as mopping floors, cleaning surfaces and vehicles.

The ‘carrot’ was the abandoned plot across the road and the promise it held as a green, open space for people to use; as there is limited space within the apartment complexes. The residents here thus came up with a solution to divert their excess treated wastewater to sustainably maintain the tree park. The idea was very well accepted and supported by the then MLA who guided the community throughout.

Dump to park

The residents first approached the city corporation, the Bruhat Bengaluru Mahanagara Palike (BBMP), to clear garbage from this site, which belongs to the state revenue department. The community then conducted a massive tree planting drive in August 2019, when 500 saplings were planted to bring this barren land back to life.

Garbage lies around the yard
The garbage dumpyard before residents cleaned it up

Construction debris lying around the site
The construction debris that was formerly lying around the site 

“We ensured regular watering and maintenance of all the tree saplings we planted for almost a year. Every week, we made sure that watering of all the saplings was done. Tanker water was used only to water the trees outside the park,” said committee members of the Spark Tree Park.

This subsequently evolved to a more sophisticated set-up. The community won a grant amounting to Rs. 2.70 lakhs by Wipro for this project, which was used to set up all the required infrastructure for sustainably maintaining the park such as pipelines, spouts, recharge wells for rainwater harvesting and the stormwater channels.

The residents installed a pipeline network which enabled the excess treated wastewater from the apartment’s STP to be directly supplied to the spouts inside the park. The treated wastewater flows from the overhead tank to the park, helping maintain the pressure required to water the park just by connecting a hosepipe to spouts without a pump.

There are three main spouts which are connected to multiple sub spouts that help water the whole park. These spouts are strategically placed along the compound wall of the park and are connected with UPVC pipes. The pipeline connecting the apartment and the park runs below the road that was recently laid.

“The tree park has a rainwater harvesting system and a surface stormwater channel that runs along the periphery of the park. We are on the lookout for a nature-based solution that could further purify the STP water,” said Vikas Agrawal, one of the park committee members.

All the trees and plants in the park are currently watered with treated wastewater from the three neighbouring apartments. This new infrastructure has helped create a healthier environment for the communities in the area. A resident told us, ‘Our children play cricket here every weekend. We are happy that we have made a park for our kids next to our home’.

Moreover, few homemakers in the community recently set up a vegetable garden which mostly consists of green leafy vegetable plants, herbs such as curry leaf, lemon and mint. This vegetable garden is secured with a short wooden fence.

“Treated water from our apartment is used for watering these plants. The garden is maintained by a few of us and we really enjoy spending time in this park,” said a Greens Apartment resident.

The CSEI has identified more such parks in Mahadevapura and Yelahanka which are sustainably maintained using treated wastewater from neighbouring apartments. The CSEI also supports the Karnataka State Pollution Control Board (KSPCB) with the Grey to Green campaign, which aims to help apartments channel their excess treated wastewater for greening public parks and medians. If you live in an apartment with excess treated wastewater right next to a park, please reach out to us at csei.collab@atree.org.

Sneha Singh is a senior researcher with the Cities and Towns Initiative at the Centre for Social and Environmental Innovation at ATREE, Bengaluru.

Watch: TNM's Let Me Explain show where Anna Isaac tells you about the new evidence in the Dileep case.

Become a TNM Member for just Rs 999!
You can also support us with a one-time payment.