| "The application of modified aerobic digestion process (liquid-composting) was examined for agricultural and horticultural use of sewage sludge. Experiments were carried out using a lab-scale airtight reactor under different tempereture conditions (20, 35, 50, 60 and 70 degrees centigrade). To keep aerobic condition, the reactor was filled with oxygen gas (2 atm). The CO2 emission under each condition was measured to estimate stabilization (or composting) process of the sewage sludge. The effect of the liquid compost on Komatsuna (Brassica campestris L.) was estimated by seedling experiment. Moreover, microbial communities were analyzed using PCR-DGGE assay. The following results were obtained from the experiment: 1) the sludge was stabilized by biological degradation for 10-14 days except 70 degree condition, 2) although the liquid compost of 60 and 70 degree conditions included inhibitor for the growth of Komatsuna, it could be degraded under 20 or 35 degree conditions, and 3) the microbial community under each condition had drastically changed for one week operation. A further direction of this study will be to apply the present process to the composting of other liquid biomass with sewage sludge." |
