enhancing ultraviolet application of disinfection technologies for saline and industrial wastewater treatment

This laboratory investigation assessed the effectiveness of ultraviolet (uv) irradiation for disinfecting saline effluent from a biological wastewater treatment process. the primary objective was to inactivate residual microbial contaminants using uv light at 254 nm wavelength. the optimal uv exposure time was found to be 280 s, effectively reducing microbial presence while achieving operational efficiency. to optimize disinfection conditions, dry ice (solid co₂) was employed for ph adjustment, with 4.8 g identified as the ideal dosage to lower the effluent ph below 9.5. in addition to microbial disinfection, uv exposure also contributed to secondary treatment effects, including a reduction in chemical oxygen demand (cod) by 41.1% and biochemical oxygen demand (bod) by 17.5%. furthermore, extended uv irradiation led to the partial degradation of certain chemical pollutants, with doc decreasing from 4.63 mg/l to 2.57 mg/l and tph from 0.039 mg/l to 0.02 mg/l. significant reductions were also observed in turbidity (38.9%), total dissolved solids (43.6%), phosphate (57.4%), and nitrate (40.6%). these results indicate that while uv radiation is primarily a physical disinfection method can also support the degradation of selected organic and inorganic contaminants.