The state government’s rule stating that groundwater cannot be used for construction purposes is posing a big issue as treated wastewater is not readily available for the purpose as per the construction industry.
BENGALURU: The Karnataka State Pollution Control Board (KSPCB) has conducted a study with the researchers at the Indian Institute of Science (IISc). They will now approach the Bureau of Indian Standards (BIS) to form parameters for treated wastewater under IS 465:2000 rule that can be used in the construction industry.
“There is a demand that does not match the supply. While I have been using treated wastewater for my construction projects for the last five years, there is also hesitancy among construction companies when it comes to recycled water. But if there is treated wastewater available with a study by IISc backing it up, the industry will surely come forward,” said a representative of the industry present at an event organised around the concept of reuse of wastewater in Bengaluru by the Centre for Social and Environmental Innovation at the Ashoka Trust for Research in Ecology and the Environment (ATREE), and the Bangalore Apartments’ Federation (BAF).
Water management should be given utmost importance in an urban landscape and ways should be found to make available affordable technology to recycle wastewater for secondary use. Experts stressed the narrative around treated wastewater has to be rearticulated.
Meanwhile, KSPCB member-secretary Srinivasulu said, “The city generates around 800 MLD of sewage every day and roughly around 50 per cent of this sewage enters the city lakes, untreated. While there is enough sewage and affordable technology, the need of the hour is that the scientific community along with KSPCB builds up momentum in the public domain and lets it be seen as a measure to provide potable water for secondary purposes in the city and arid districts surrounding it,”
Syed Khaja, senior environment officer, KSPCB added, “The most difficult aspect of the reuse of treated wastewater is its utilisation in the construction industry. While we have IS 456:2000 rule that talks about standards of regular water for construction purposes, no parameters have been drawn out for the usage of treated water. However, soon we will have BIS standards for treated sewage for construction purposes too. This will be the first-of-its-kind initiative across the world,”
The experts finding from KSPCB said the initial results show that the recycled water is safe to be used for construction while the board is planning to approach BIS.
“One cause of concern has been its impact on the steel strength due to higher content of sulfur and sodium. We conducted tests and we found out that the concrete hardens within two days and the temperature inside reaches around 80 degrees Celsius. At this temperature, the availability of moisture is unlikely. Moreover, the corrosion process begins only after a minimum period of 14 days. Thus, the tensile strength will not be compromised,” added Khaja.
While KSPCB will wait for BIS’s nod before it starts to advocate using treated wastewater in the construction of buildings and for load-bearing structures, experts said that the recycled water can already be used for the curing process. “Around 60 per cent of water consumption in the construction sector is for curing. Treated water can find its use here immediately,” informed Khaja.