Effect of aeration rate on composting of penicillin mycelial dreg

Pilot scale experiments with forced aeration were conducted to estimate effects of aeration rates on the performance of composting penicillin mycelial dreg using sewage sludge as inoculation. Three aeration rates of 0.15, 0.50 and 0.90 L/(min·kg) organic matter (OM) were examined. The principal physicochemical parameters were monitored during the 32 day composting period. Results showed that the higher aeration rate of 0.90 L/(min·kg) did not corresponded to a longer thermophilic duration and higher rates of OM degradation; but the lower aeration rate of 0.15 L/(min·kg) did induce an accumulation of NH₄⁺-N contents due to the inhibition of nitrification. On the other hand, aeration rate has little effect on degradation of penicillin. The results show that the longest phase of thermophilic temperatures ≥ 55°C, the maximum NO₃⁻-N content and seed germination, and the minimum C/N ratio were obtained with 0.50 L/(min·kg) OM. Therefore, aeration rates of 0.50 L/(min·kg) OM can be recommended for composting penicillin mycelial dreg.