Performance of an upflow anaerobic filter in the treatment of cold meat industry wastewater

• Nutrients were determinant in biomass adaptation and self-generated alkalinity.
• Biomass adaptation decreased time of staring-up and stabilization of the UAF.
• Removal efficiencies of total COD attained 84% in the UAF reactor.

Treatment of cold meat industry wastewater was performed in an upflow anaerobic filter (UAF) analyzing the effect of the physicochemical characteristics of the wastewater, which contains high concentrations of organic matter expressed as total chemical oxygen demand (COD) (3500 mg L−1) and total biochemical oxygen demand (BOD) (2035 mg L−1), fat oil and grease (FOG) (1114 mg L−1), in addition salts (nitrogen and phosphorus), additives, colorings, flavorings and others. The biomass used was previously adapted to the cold meat wastewater in a batch reactor, reducing the total COD and total BOD concentrations by 81% and 87% respectively over a period of 15 days and ensuring to decrease time of staring-up and stabilization of the UAF. Removal efficiencies of total COD and total BOD attained 84% and 88% respectively in the UAF reactor, operating at organic loading rates ranging from 1.17 to 3.5 kg COD m−3 day−1 at 37 °C and pH 7; methane production yield at operating conditions in the stable period of operation reached 422 mL CH4 (g CODremoved)−1. Physicochemical characteristics of the wastewater, particularly nutrient concentration was determinant in the biomass adaptation and in the self-generated alkalinity, two parameters that greatly contributed to the performance and stabilization of the reactor.