Potential use of treated sewage in concrete to meet water crises in megacities

Water scarcity is one of the most important issues wherein countries are becoming water-stressed. India's dependency on groundwater has increased between the years 2004 and 2013 and each state of the country is facing a decline in the water table due to the growing requirements. Acute water shortage and high-water demands are from sectors like agriculture, industrial, and construction. The construction industry is accountable for the enormous consumption of water as the Indian guidelines recommend the use of potable water for concrete. The present study investigates the use of treated sewage as mixing and curing water in concrete. Comprehensive tests on fresh and hardened concrete have been carried out for each concrete mix, like, setting time, workability, compressive strength, rapid chloride permeability test and water permeability. Potable water was replaced by weight in ratios of 50%, 80%, and 100% of the treated sewage in the mixing and curing of specimens. The water to cement (w/c) ratio has been taken is 0.45 for potable and treated sewage concrete. Compressive strength and durability have been tested after 7, 28, 56, and 90 days of curing. It can be concluded that treated sewage has the potential to replace fresh potable water in concrete mixing and curing and shall be included in relevant guidelines.