Wastewater: Waste or Resource?
Construction industry consumes enormous amount of water, second only to agriculture. The activities of construction in water stressed regions add to the already prevailing problems related to availability of potable water for daily use. Cement is the second most used material after water and its production and use involves huge quantity of potable and fresh water. The water consumption for cement has varied between 250-305L/tonne of cement production4. It is worrisome to know that concrete industry was responsible for 1.7%5 of all global water withdrawals. It is also expected that between 2012 and 2050, India will increase its concrete production by 90%6. Thus, it is important to have access to recycled wastewater that can be used by the construction industry.
Currently, the wastewater generation of urban India is 617547 MLD while the treatment capacity is 22963 MLD. This treated wastewater is mostly used in the agriculture sector and for ground water recharge, horticulture purpose and for maintaining base flow of rivers, ponds and water reservoirs. Unfortunately, treated wastewater is not seen as a major resource in India yet. The secondary and tertiary treated wastewater as per CPCB norms can be put to much efficient use. To adopt this in a sustainable manner, using treated wastewater by replacing potable water in the construction industry could be a viable option that must be deliberated upon. Few research studies have been conducted on this at a very small scale in laboratories but in India it has not yet been considered. Efforts must be taken through the aegis of government departments and industries together to conserve fresh water resources and view the treated wastewater as a resource. ■
2 http://nwm.gov.in/?q=synopsis-water-data-india (Website accessed on 18th August 2020)
3https://www.thehindubusinessline.com/economy/agri-business/indias-per-capita-water-availability-to-decline-further-icar/article29342714.ece (Website accessed on 18th August 2020)
4 https://www.globalcement.com/ (Website accessed on 18th August 2020)
5 Miller, S. A., Horvath, A., & Monteiro, P. J. (2018). Impacts of booming concrete production on water resources worldwide. Nature Sustainability, 1(1), 69-76.
6 https://www.fluencecorp.com/concrete-industry-water-use/ (Website accessed on 16th August 2020)