Treatment of wastewater from a cotton dyeing process with UV/H2O2 using a photoreactor covered with reflective material

摘要

Wastewater containing several dyes, including sulfur black from the dyeing process in a textile mill,nwas treated using a UV/H2O2 process. The wastewater was characterized by a low BOD/COD ratio,nintense color and high acute toxicity to the algae species Pseudokirchneriella subcaptata. Theninfluence of the pH and H2O2 concentration on the treatment process was evaluated by a full factorialndesign 22nwith three replicates of the central experiment. The removal of aromatic compounds andncolor was improved by an increase in the H2O2 concentration and a decrease in pH. The best resultsnwere obtained at pH 5.0 and 6 g Lu00011n. With these conditions and 120 min of UV irradiation, the removalnof the color, aromatic compounds and COD were 74.1, 55.1 and 44.8%, respectively. Under the samenconditions, but using a photoreactor covered with aluminum foil, the removal of the color, aromaticncompounds and COD were 92.0, 77.6 and 59.4%, respectively. Moreover, the use of aluminum foilnreduced the cost of the treatment by 40.8%. These results suggest the potential application ofnreflective materials as a photoreactor accessory to reduce electric energy consumption during thenUV/H O process.