Assessment of nanobubble aeration performance in treating poultry slaughterhouse wastewater

Abstract

Due to their simplicity and effectiveness, biological treatment methods, including aerobic and anaerobic processes, are widely used for treating medium to high-strength wastewater, such as poultry slaughterhouse wastewater (PSW). Conventional aeration methods, although effective in removing organics and nutrients from wastewater, have drawbacks such as high sludge production, substantial energy consumption, and low oxygen transfer efficiency. To overcome these challenges, technologies such as nanobubble (NB) technology have been developed to enhance aerobic processes by optimising aeration methods and gas diffusion. NBs, with diameters less than 200 nm, have emerged as a promising alternative due to their ability to enhance the efficiency of aeration and reduce sludge production. NBs possess unique properties that contribute to physical, chemical, and biological processes in water and wastewater treatment. This research investigates the performance of NB technology in the application and enhancement of aerobic treatment of PSW. Three NB aeration methods were evaluated: air- NBs, ozone-NBs, and air-NBs combined with Ecoflush enzymes. These methods were tested for their effectiveness in removing chemical oxygen demand (COD), total suspended solids (TSS), ammonia (NH3-N), total nitrogen, and fats, oils, and grease (FOG) over a period of 6 h. Air-NB and ozone-NB aeration methods demonstrated high efficiency in COD removal, achieving over 80% removal within just 2 h of treatment. In contrast, NBs combined with Ecoflush enzymes exhibited initially lower COD removal rates (20%) in the first 4 h but ultimately achieved 86.8% removal of COD and 99.5% removal of FOG after 6 h of aeration. TSS removal efficiency remained consistent across all aeration methods after 4 h, with the ozone-NB method showing the highest removal efficiency. Ammonia removal was most effective when using NBs combined with Ecoflush enzymes, reaching 99% removal after 6 h of treatment. Both the ozone-NBs and NBs combined with Ecoflush enzymes showed high FOG removal capabilities. These findings highlight that nanobubbles can significantly enhance mass transfer in wastewater treatment processes, providing an effective method for improving the degradation of pollutants in PSW.