Abstract Ammonia is a major odoriferous component in the vent gas of the fermentation process of poultry manure compost. To prevent environmental problems, it is full-scale and a lab-scale biotrickling filters (BTF) were used for treatment of ammonia in air streams. The full-scale BTF was constructed by reinforced concrete (inner size = 6 m square ¡Ñ 5 m height) with PVC plate packings (total volume =6 m square ¡Ñ 3 m height = 108 m3 , specific area = 100 m2/m3). Long-term (357 days) experimental results show that, in the conditions of gas empty-bed-retention time EBRT = 35-77 s, liquid-gas ratio L/G = 5-11 L/m3, and recirculation liquid pH = 6.5-6.8, 6.5-29.8 ppm (average 14.3 ppm) ammonia in the influent gas could be reduced to 0-2.0 ppm (average 0.66 ppm). Daily rates were supplementary water = 0.400 m3, discharge water = 0.360 m3, supplementary H3PO4 (85%) = 0.28 kg. With the average volumetric ammonia loading of 0.66 g NH3-N/m3h, the system could achieve an average nitrification efficiency of 62% without supplementary glucose. Ammonia removal efficiencies of over 90% were obtained with recirculation liquid pH¡Ø6.8, and below 22% with pH¡Ù7.33. The lab-scale BTF consisted of a set of two-stage-in-series biotrickling filters, an influent gas supply system, and a liquid recirculation system. Each stage of the biotrickling filter was constructed from a 20 cm ¡Ñ 200 cm (inside diameter ¡Ñ height) acrylic column packed with cokes (average diameter = 3.0 cm and specific area = 150 m2/m3) of 125 cm height. Experimental results indicate that a time of 30 days was required for development of biofilms for nitrification of the absorbed ammonia from the gas. Long-term (187 days) experimental results show that, in the conditions of EBRT = 7.25 s, L/G=7.7 L/m3, and liquid pH=6.65, 230 ppm ammonia in the influent gas could be reduced to 4.0 ppm. With the volumetric ammonia loading of less than 7.37 g NH3-N/m3h, the system could achieve ammonia removal and nitrification efficiencies of 98 and 94%, respectively, without supplementary glucose. However, with a loading of 13.1 g NH3-N/m3h, both decreased gradually due to a lake of carbon (glucose) source and an accumulation of nitrite and nitrate in the recirculation liquid.