With a water crisis looming and extraordinary measures such as a ban on construction activities in the city being mooted, BWSSB officials and experts say that it is high time the builders and house owners use recycled water so that the river and underground water can be conserved.
Bangalore Water Supply and Sewerage Board (BWSSB) says that it treats close to 1,067.5 MLD (million litres per day) of wastewater daily and yet this water is hardly bought for construction activities.
“Among the total treated water, 250-265 MLD of water is going to Kolar fields. And the rest goes to the lakes of the city and around and Raja Kaluves (storm water drains). Close to 90 per cent of the STPs also lie either in the lake or its periphery. Even though I can’t categorically predict how the future will be, I suppose within three to four years people will get used to recycled water as their conventional sources might disappear during time,” said, Nithyananda Kumar Chief Engineer (Wastewater management) BWSSB.
According to experts there are two types of ‘treated’ wastewater – secondary treated water and specially treated water. The secondary treated water is sold at around Rs. 10 per kilo litre, if it is transported in lorry and tanker and Rs 15 per kilo litre if it is transported through pipelines.
BWSSB also goes for specially treated water, which comes up to Rs 15 per kilo litre (if through lorries and tankers). Rs 25 per kilo litre, if transported through pipelines.
“If you look at the construction space, the water is supplied through tankers or sometime sourced through the piped Cauvery water. The tanker water is mostly the borewell water. If you look at the usage of the water during construction work, it is mostly for curing the building or mixing purpose. So, we would suggest going for treated water for these activities. Even if half of the construction activities switch to treated water, then we can save a lot of ground water. A house constructed on 1,000 square feet (single floor) would require anywhere between 50,000 to 70,000 litres of water in case the construction spans from six to 10 months. So, now one can imagine how much water can be saved if one shifts to treated water,” said an official.
Prof. T.J. Renukaprasad, Chairperson, Department of Geology, Bangalore University added, “At present, in my observation, not even 10% of treated water is utilised by Bengalureans in its possible ways. Considering the present state of water and the crisis the city is staring at, instead of extracting groundwater through borewells, it is advised to use treated water in construction sites and other possible uses like gardening and agricultural uses. On an average, it requires about 130-150 litres of water per person for daily use.”
Renukaprasad said people can collect water in two ways: The water with soap or detergents can be directly used for gardening and bathroom wastewater can be used in toilets after a small oxidation process and exposure to sunlight. “Treated water can easily be used at construction sites for mixing concrete and curing of the new buildings. People can do away with use of groundwater for such purposes,” he said.