Treated water is a crisis-fix for Bengaluru, but quality matters

Allowed by a recent government order to sell the excess water to industries, apartments in Bengaluru are now looking at how to channelise the treated water

May 02, 2024 09:00 am | Updated 09:00 am IST - Bengaluru

Sewage Treatment Plant on Vishwabhati River on Mysore Road in Bengaluru.

Sewage Treatment Plant on Vishwabhati River on Mysore Road in Bengaluru. | Photo Credit: BHAGYA PRAKASH K

Is treated water a sure-shot fix for Bengaluru’s perennial crisis? After decades of inaction, the unprecedented water crisis this summer has finally activated both the government and consumers to take a serious look at this alternative. Baby steps are underway, but how soon can these be scaled up to make a city-wide impact, and does the quality of the treated water inspire confidence?

Treated water was always a low-hanging fruit. A 2016 rule mandating Sewage Treatment Plants (STPs) to be built and maintained in all apartments with over 20 residential units has led to an estimated 2,600 decentralised plants across the city. The rule has been relaxed recently, but the existing STPs in apartment complexes generate a substantial 700MLD of treated water.

Industries and construction firms that relied on Cauvery and tanker-supplied borewell water could have switched to this large reservoir of treated water, easing the crisis. But there was a catch. The apartments that reused half of the treated water for multiple inhouse activities, had no way to dispose of the remaining water in a sustainable way. A pilot project by the Bengaluru Apartments Federation (BAF) could be a start.

Apartments to industries

Now allowed by a recent government order to sell the excess water to industries, apartments are looking at how to channelise the treated water. The BAF pilot will focus on the Bellandur ward, studying the volume of treated water available in multiple apartments and match it with the demand from industries, commercial setups and construction sites in the area. Sales will follow.

BAF and the Bangalore Water Supply and Sewerage Board (BWSSB) has already inked a deal to facilitate the sale. The Board has announced that it will buy the water and supply to establishments through tankers. Once the pilot sets up a pattern, both BAF and the Board have proposed a scale-up plan, incorporating even pipelines from the apartments to industries.

The big idea is to evolve a standard operating procedure and demonstrate that a treated water network can be put in place first within a small area. “We want to start with a cluster. We can look at laying a pipeline from a community to a construction site in close proximity. If another such site comes up in the future, the pipeline can be diverted there. Of course, it needs engineering, planning, support from various authorities,” says K. Arun Kumar, Water Head at BAF.

The government notification on sale of treated water limits it to 50% of the total volume generated in an apartment. “The rest could be donated for multiple purposes such as rejuvenation of lakes. We wanted more than 50%. But this is at least a start,” he notes.

Tankers now, pipelines later

For now, the transport mode will be tankers and the cost will be borne by the BWSSB or whoever the buyer is, Arun points out. “Let them bring buckets or water, we will sell only the water. The ₹8 a kilo litre agreement with the BWSSB will not cover the cost. By selling a tanker of 6,000 litres, we get ₹48. Ferrying even a litre of water in an autorickshaw will cost that much,” he explains.

But beyond the cost equation lies the quality of water supplied. While issuing its order on treated water sales on March 22, BWSSB had insisted that the quality has to be compliant with National Green Tribunal (NGT) standards. In this direction, BAF wants to explore the possibility of barcoding the water and adopting new technologies for instantaneous testing. The aim: To ensure that the quality of water sent from the apartment matches with the tested sample at the industry / construction site.

Quality concerns

Odour is an oft-cited complaint about treated water. To address this, the Federation has proposed to evolve a method of expiry date for water. Storage beyond a particular date will lead to the odour.

Quality upgrade is a must if treated water is to bring a dramatic shift in Bengaluru’s demand-supply equation. This implies the quality of the STPs in apartments, besides the 36 operated directly by BWSSB, are in ship shape. There is clearly a huge gap in checks and balances, as Nagesh Aras, a seasoned analyst of STPs in the city, points out.

Efficiency of both private and public STPs are below par, he says, squarely blaming the Karnataka State Pollution Control Board (KSPCB). An apartment builder / developer has to obtain a Consent for Establishment (CFE) and Consent for Operation (CFO) in two stages before clearing a STP. He finds gaps in the processes, documentation on design, type of the STP selected and more.

No checks and balances

As a prerequisite to approve and operationalise a treatment plant, the Board is required to check all the plans, specifications and other data related to the STP, inspect the machinery, and quality of the treated output at the point of disposal. The building can be granted an Occupancy Certificate (OC) only if the STP has a CFO. Property transfer from the builder to individual apartments is also dependent on this.

The Board, as Nagesh explains, is mandated to block or delay this transfer if it spots any defect in the STP after a thorough inspection. The clearance can come only after all the defects are rectified. “The builder himself is often not interested in building a good, working STP. Even if he is sincere, he does not have any in-house capability. So he hires some consultants who are also suboptimal, and they design terrible STPs. And when the checks and balances are not there from the KSPCB, the whole thing completely runs aground.”

Beyond the apartments, the bulk of the waste water generated by the city is treated by the 34 STPs operated by BWSSB. But most of these plants, says Nagesh, do not go through the CFE / CFO process. A large number of individual houses, particularly on the city’s outskirts, are not connected to these STPs. Raw sewage is let off into the storm water drains leading to the lakes.

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