Fig 1: Pramuk Aqua Heights (Left: Location on the map; Right: Satellite view of the apartment and the Veerasandra Lake)
Pramuk Aqua Heights, an apartment complex built in 2015 in Electronic City, has 269 flats and is located right next to Veerasandra Kere on NH48. The apartment complex is not connected to the municipality drainage system but produces an excess of about 140 KL of STP-treated water despite using it for flushing, cleaning and gardening. Hence, they were forced to send out this treated water through tankers which cost them around ₹2000 – 3000 per day.
To avoid this costly scenario, in September 2021, the apartment complex installed a tertiary treatment technology from Transwaters that not only helped combat the problem but also turned it into a profitable endeavour.
Boson White Water – the tertiary treatment system
Installed in September 2021, Tranwaters’ tertiary treatment system, Boson White Water, converts the secondary treated water from the installed STP to potable quality.
It occupies space equivalent to two car parks.
The company pays rent for the space and the electricity bill for the operation of the plant to the apartment complex.
About 8 units/litre of electricity is consumed for the treatment process.
The plant produces 75% tertiary treated water and 25% reject water that is fed back into the STP.
About 100 KL of potable quality water is produced in the apartment complex from used water.
In-situ water quality testing is carried out by Transwaters every day.
Tanswaters also pays for the transport of this potable quality water to various end destinations around the city.
End use of the tertiary treated water
Due to its potable quality, the tertiary treated water is put to good use in various scenarios and is sold at ₹0.08/litre.
Laundry services: Due to its potable quality, Biocon’s laundry service (in the neighbourhood) that buys this water is using around 275 gms less detergent per load. Due to the reduced detergent consumption, the in-situ effluent treatment plant also uses 1/3rd less chemicals to treat their used water.
Cooling towers in IT parks/malls etc: Since the tertiary treated water is soft, it eliminates the need for salts in cooling towers that would otherwise be needed to reduce the hardness of the borewell/tanker water.
Swimming pool: Pramuk Aqua Heights apartment has also started using this water in their swimming pool, thus eliminating the need for fresh water.
The amount spent on sending the STP-treated water out through tankers has been eliminated, while the apartment is earning through renting out the space for the tertiary treatment plant.
Tertiary-treated water is cheaper than tanker water.
End users save by reducing/eliminating the need for buying and storing the required chemicals to deal with hard water.
Cost of 50 KL tanker water per day (₹)
Cost of 50 KL tertiary treated water per day (₹)
Cost savings per day (₹)
Savings per month (₹)
Cost savings using 50 KL tertiary treated water instead of tanker water for a cooling tower
Environmental impact: Elimination of the need for chemicals/detergents in the various end uses leads to cleaner air, soil and water.
Business impact: An environmentally beneficial business has been created in the city in the form of the tertiary treatment system.
Boson White Water treatment plant
Daily water quality report
Tertiary treated water being filled in the swimming pool