Abstract

This study investigates the effectiveness of plasma treatment in degrading organic contaminants from denim industry wastewater using a dielectric barrier discharge (DBD) plasma jet. A 3-way full factorial design was applied to evaluate the influence of treatment time, power, and airflow rate on degradation efficiency. Initial tests on dyes such as crystal violet, congo red, methylene blue, and indigo confirmed the efficacy of the plasma jet, with degradation efficiencies of 96.3%, 86.3%, 93.4%, and 97.8%, respectively, within treatment times ranging from 8 to 60 min. For denim industry wastewater, plasma treatment resulted in notable reductions in chemical oxygen demand (COD), with 35.0% removal for virgin wastewater and 15.9% for industry-treated wastewater. Total organic carbon removal increased by 42.6% for virgin wastewater and 18.2% for industry-treated wastewater, indicating substantial mineralization. Toxicity analysis showed that plasma-treated wastewater supported freshwater algae growth, suggesting a non-toxic nature and enrichment with nitrogen-based nutrients. Regression analysis and optimization identified plasma treatment time and power as the key factors in maximizing COD removal. Under optimal conditions, COD removal reached 97.65% for virgin wastewater and 98.1% for industry-treated wastewater. In conclusion, plasma treatment offers an effective and sustainable method for wastewater management in the textile industry, ensuring significant pollutant degradation, improved water quality, and a non-toxic, nutrient-rich effluent suitable for environmental applications.