Rs. 1.73 crore Centre-funded project to reclaim 3 to 4 million litres of precious water currently wasted daily

Mysore/Mysuru: Following Bengaluru’s lead, the Vani Vilas Water Works (VVWW), the water supply arm of the Mysuru City Corporation (MCC) will soon feature a state-of-the-art Backwash Water Treatment Plant.

Backwashing, a key procedure in water and wastewater treatment, involves pumping water backwards through a filter to remove accumulated debris and particles. In Water Treatment Plants (WTP), this process can be automated using local Programmable Logic Controllers (PLC).

At VVWW the Backwash Water Treatment Plant is being constructed at a cost of Rs. 1.73 crore, funded by the Union Government’s Finance Plan (2020-21). This initiative aims to reclaim 3 to 4 million litres of precious water currently wasted daily, optimising the utilisation of available water resources.

The VVWW, which receives water from the Belagola Pumphouse established by the erstwhile Mysuru Maharajas decades ago, filters raw water through a series of processes including aeration, sedimentation, filtration and chlorination before distributing it to the city residents. Continuous filtration results in the accumulation of mud, debris and particles, necessitating periodic backwashing.

According to VVWW Assistant Executive Engineer Mohammad Mustafa, backwashing of granular media filters involves several systematic steps. Initially, the filter is taken offline, and water is drained to a level above the filter bed surface.

Subsequently, compressed air is injected upwards through the filter material, causing the filter bed to expand and dislodge compacted particles into suspension.

Following the air scour cycle, clean backwash water is then forced upwards through the filter bed, further expanding the bed and carrying suspended particles into designated troughs positioned above the filter surface. Mustafa noted that the backwashing process continues for a predetermined duration or until the turbidity of the backwash water falls below a specified threshold.

Mustafa further emphasised that turbidity levels are measured using Nephelometric Turbidity Units (NTU), a standard unit for assessing suspended particles in water. He highlighted that the establishment of the backwash water treatment plant will provide an additional 3 million litres per day (MLD) of water.

Out of this, 500,000 litres (0.5 MLD) will be allocated to Cheluvamba Hospital, while the remaining 2.5 MLD will be distributed among the city residents.

In addition, he outlined plans to develop similar backwash water treatment plants at Melapura, Hongalli, and Kabini water pumping stations. He mentioned that proposals for these initiatives will be submitted to the Government pending the availability of funds.