The performance of a pilot-scale anti-clogging biofilter system (ABS) was evaluated over a period of 125 days for treating ammonia and volatile organic compounds emitted from a full-scale food waste-composting facility. The pilot-scale ABS was designed to intermittently and automatically remove excess biomass using an agitator. When the pressure drop in the polyurethane filter bed was increased to a set point (50 mm H(2)O m(-1)), due to excess biomass acclimation, the agitator automatically worked by the differential pressure switch, without biofilter shutdown. A high removal efficiency (97-99%) was stably maintained for the 125 days after an acclimation period of 1 week, even thought the inlet gas concentrations fluctuated from 0.16 to 0.55 g m(-3). Due the intermittent automatic agitation of the filter bed, the biomass concentration and pressure drop in the biofilter were maintained within the ranges of 1.1-2.0 g-DCW g PU(-1) and below 50 mm H(2)O m(-1), respectively. (C) 2011 Elsevier Ltd. All rights reserved.