Cell immobilized lipase-producing bacteria on three different matrices were incorporated in a fat-, oil-and grease (FOG) trap system for restaurant wastewater treatment. During a 16-day lab-scale experiment for the treatment of synthetic FOG wastewater containing soybean oil, no significant difference (two-tailed t-test at 95% confidence interval) in the FOG removal between two systems was observed at FOG influent ≤1000 mg/L. However, the typical trap showed lower FOG removal efficiency than

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... matrix-based system when the influent FOG concentration was increased to ≥5000 mg/L. In addition, the matrix-based trap system was able to sustain a stable high FOG removal, with <100 mg/L effluent, even at 10000 mg/L influent FOG. Based on FOG heights measured and mass balance calculations, 97.4-and 99.5% of the total FOG load for 16 days were removed in a typical trap and matrix-based system, respectively. About 93.6% of the removal in the matrix-based was accounted to biodegradation. The 30-day full-scale operations demonstrated a distinguishably better performance in the matrix-based system (92.7±9.06% of 1044.8±537.27 mg FOG/L) than in the typical trap system (74.6±27.13% of 463.4±296.87 mg FOG/L) for the treatment of barbeque restaurant wastewater. Similarly, matrix-based system revealed higher COD removal (85.9±11.99%) than the typical trap system (60.4 ±31.26%). Characterizations of the influent, emulsified, adsorbed and effluent FOG indicated that straight saturated fatty acids (SSFA) constituted the cause of clogging problems in the FOG trap and piping system.