Treading greywater: Infosys orders 4 lakh litres treated waste water from BWSSB

Bengaluru: After Wipro, now Infosys has also taken a plunge into greywater. The tech giant will soon be supplied with four lakh litres of zero-bacteria water, according to sources in the Bangalore Water Supply and Sewerage Board (BWSSB).

Starting this month, Wipro is being supplied with three lakh litres of treated water every day via tankers.

"We already have Arvind Mills committing to two lakh litres a day and Channabasappa Construction one lakh litres. I just had a meeting with Ecospace Tech Park and IMZ Ecoworld, they too have expressed interest. The movement is slowly picking pace," said BWSSB chairman V Ram Prasath Manohar to PTI.

Promoting reuse of greywater is important, said Manohar, as water demand in Bengaluru is projected to cross 5,340 million litres per day (MLD) by 2030. Right now, the demand exceeds 2,100 MLD of which BWSSB supplies 1,470 MLD from the Cauvery River and the rest is met through borewells and water tank deliveries.

"But treated water is always available. Promoting its reuse will bring down pressure on Cauvery," added Manohar.

However, it still is a long way, as BWSSB is reusing only about 10 MLD while it produces 1,200 MLD.

"So, in effect, it’s literally just a drop in the ocean of sewage water. But we need to start somewhere," he said.

Although eventually BWSSB, if we go by its Vision Document 2050, hopes to convince people to even drink reused water, by using advanced treatment technologies to produce high-quality water that exceeds drinking water standards, as of now this is still a pipe dream. Mostly because people find it disgusting to even think about drinking what was once sewage.

Manohar said when big companies start using reused water, it will send a positive message and will eventually bring about a behavioural change in people.

"From macro-level or industrial usage, it will eventually percolate to micro-level or private consumption," he added.

In its 2021 study on public perception of reuse of greywater or treated water, Recycled water reuse: what factors affect public acceptance, Cambridge University concludes that identifying the groups with the potential to influence outcomes is critical in promoting reuse of water.

BWSSB seemed to have found its ‘groups with potential to influence’ in big tech parks and multinational companies.

"This is a win-win situation, in the shorter term too. After spending money to treat water, letting it into drains is an economical waste. Now, with these companies coming forward, BWSSB could make some money out of it, which in turn could be used for future projects," Manohar said.

The companies too benefit as they get water for their non-potable needs at a substantially reduced cost, he said.

"Now they spend Rs 125 for 1,000 litres, while treated water is available for Rs 20 to Rs 30 per 1,000 litres. Plus, they can claim that they are using sustainable measures to achieve water security," the BWSSB chairman added.