Microwave Processing at the 915 MHz Frequency for Efficient Cleavage of Cellulose and Lipids in Vegetable and Meat Wastewater Treatment

Meat and vegetable processing wastewaters are challenging to treat due to high concentrations of recalcitrant organic compounds-such as fats, oils, and cellulose-that resist conventional degradation. This study systematically evaluated the use of 915 MHz microwave (MW) processing, focusing on the effects of specific energy flux (SEF, in J/kg·s), total solids (TS) concentration, and flow rate on enzymatic activity and physicochemical properties. In vegetable processing wastewater, optimized MW conditions (SEF = 3,244.21 J/kg·s, TS = 2%) maximized cellulase activity (50.09 U/mL) and glucose release (0.1551 mg/mL), whereas higher TS (4%) reduced treatment efficacy. In meat processing wastewater, increased SEF (up to 2,775.51 J/kg·s) enhanced lipase activity (29.88 U/mL, 0.45 mg/mL), reduced viscosity and density, and altered the organic acid profile by increasing propionic acid and decreasing acetic acid. Statistical analysis confirmed SEF as the primary driver of biochemical and thermal changes (R² > 0.89). These results demonstrate that optimized 915 MHz MW processing is a scalable, sustainable, and regulatory-compliant technology for food industry wastewater management. The approach improves enzymatic hydrolysis, biodegradability, and resource recovery, while reducing environmental impact and operational costs. Further research is recommended to validate these findings under full-scale industrial conditions.