Ozone-Enhanced Biologically Active Filtration for Wastewater Reuse

With climate change, population growth, and water scarcity, there is a growing demand for a sustainable approach to managing water resources. Ozonation followed by biologically active filtration (BAF) recently has drawn interest because of the synergistic effects that enhance performance and reduce operating costs associated with media replacement and ozone dosage. To help guide future process design, a comprehensive pilot study was undertaken to investigate operating parameters of the combined ozonation and BAF process. The study started in January 2014 at Hammarby Sjostadsverk Wastewater Treatment Plant in Stockholm, Sweden; the process included an ozone contactor and biologically active filters. Anthracite and granular activated carbon (GAC) produced similar results in terms of chemical oxygen demand (COD) and ammonia removal, achieving approximately 50% COD removal and reducing ammonia nitrogen to < 0.2 mg/L. Ozone plays an important role in oxidizing micropollutants. GAC demonstrated additional polishing effect for residual micropollutants, whereas anthracite showed additional little removal.