Sustainable treatment of surgical cotton processing effluent through coupled biological and photocatalytic reactors

The growing demand for surgical cotton in the healthcare sector has led to increased production in southern Tamil Nadu, generating effluents that pose environmental risks due to their chemical composition. Unlike conventional textile effluents, surgical cotton processing wastewater is distinct for its lack of colour additive, but it exhibits high chemical oxygen demand (COD) and contains significant inorganic pollutants, necessitating tailored treatment strategies. Despite extensive research on textile wastewater, effective solutions for surgical cotton effluents remain underexplored. This research bridges this gap by exploring a novel synergic method, algae-bacterial symbiosis combined with photocatalytic degradation for real surgical cotton effluent, in order to ultimately improve the removal ability of the contaminants. The general aim was to study the performance of three continuous reactor, a photocatalytic reactor, a biological rector and coupled biological-photocatalytic (CBPCR) reactor in the degradation of surgical cotton processing effluent during 30 days. The treatment efficacy was measured by observing the removal rates of inorganic nutrient, COD, and microbial growth. It was concluded that the CBPCR system successfully removed nitrate, phosphate, ammonia, and COD by 90%, 87%, 75%, and 93% respectively. In particular, the system fostered vigorous growth of both microalgae and bacteria, as indicated by a total chlorophyll concentration of 20.1 ± 0.91 mg/L and a dry cell weight of 1.81 ± 0.09 g/L. This paper shows the feasibility of the CBPCR system as a green, sustainable strategy for the treatment of surgical cotton effluent and as such fills a gap in current practice of industrial wastewater treatment.