The effect of aeration rate on forced-aeration composting of chicken manure and sawdust

The composting of chicken manure and sawdust has been investigated in forced-aeration composting systems at aeration rates of 0.3, 0.5, and 0.7 l min−1 kg−1 organic matter (OM), corresponding to pile A, pile B, and pile C. The temperature exceeding 55 °C in pile A and pile B remained more than three consecutive days, but only 2 days were above 55 °C in pile C. The final electrical conductivity (EC) did not exceed the limit content of 3000 μs cm−1 in the three piles, and the cation exchange capacity (CEC) met the requirement maturity degree of over 60 cmol kg−1. The OM loss contents in pile A, pile B, and pile C were 14%, 15.4%, and 12.8%, respectively, corresponding to the final C/N ratio of 17.1, 16.2, and 18.3. The final NH 4 + -N content in pile A did not meet the limit value of 400 mg kg−1, respectively, and the NO 3 - -N was 1942, 2190, and 1638 mg kg−1 in pile A, pile B, and pile C. The final germination index (GI) for pile A, pile B, and pile C was 90.2%, 95.2%, and 79.4%.