Abstract: Deep pit system is a commonly used method for swine manure collection，and the collected waste is then treated using biogas engineering.However，there is a lack of information about the effects of deeppit conditions on the following anaerobic digestion of the effluents. In this study，swine manure and urine were collected and mixed，and the mixture was stored under six different condition formed by 3 storage temperatures of 20℃ and 30℃ and 3 storage times of 7，14 and 21d to produce deep pit effluents，which were used as substrate to investigate the effects of the characteristics of deep pit effluents on anaerobic digestion.The results showed that the daily averaged methane production rate（MPR）of the deep pit effluents ranged from 369.2 to 702.0mL/g，and the daily average MPR kept at high level during the first 7 days into trials，and then dropped rapidly and reached a lower level on the 10 days of digestion process，after that the daily average MPR kept at relatively lower level and decreased very slowly.Ammonia nitrogen exhibited inhibition effects on MPR，and the relation between methane yield per VS and ammonia nitrogen could be expressed as y=4×10-5x2-0.3618x+1283（R2=0.9846）.The higher the TS content of deep pit effluent，the lower methane production.Therefore，it is possible to improve methane production of anaerobic digestion via shortening the storage period of swine manure in deep pit.

Key words: Swine manure, Deeppit, Anaerobic digestion, Biogas, Methane yield