Enhancing textile wastewater sustainability through calcium hypochlorite oxidation and subsequent filtration with assistance from waste blast furnace iron slag

The textile industry is vital to Bangladesh's economy, employing over three million women and being the top foreign exchange earner. However, it severely impacts the environment because of untreated wastewater discharge. High treatment costs, reliant on expensive imported chemicals, worsen the issue. The Environmental Conservation Rules (ECR) 2023 of Bangladesh requires textile wastewater discharge to have a colour of less than 150 Pt‐Co, which current systems struggle to meet affordably. A pilot project tested a sustainable solution using chemical oxidation with calcium hypochlorite and sand filtration with blast furnace iron slag. This method effectively removed colour, and the treated water showed total dissolved solids (TDS) levels of 157 ± 4 mg/L, total suspended solids (TSS) levels of 8 ± 2 mg/L and chemical oxygen demand (COD) levels of 9 ± 3 mg/L, with reductions of 92%, 87% and 94%, respectively, making it a viable solution for resource‐limited economies. Highlights The research utilized calcium hypochlorite and iron slag to treat textile wastewater, which reduces reliance on costly imported chemicals and energy‐intensive systems. The treatment process effectively addresses the ECR 2023, which requires textile wastewater discharge to have a colour of less than 150 Pt‐Co. The pilot‐scale plant demonstrated average removal efficiencies of 92% for TDS, 87% for TSS and 94% for COD and achieved complete colour removal. The tertiary treated water meets the standards of ECR 2023 producing water, which can be reused in the textile industry.