Effect of aeration and intensity on solids decomposition in manure stabilization

A 30-day bench-scale aeration experiment was carried out with three different aerationlevels, i.e., +35 mV ORP, 1.0 mg O2 L-1, and 3.0 mg O2 L-1, to treat swine manure with solids levelsfrom 0.5% to 4.0% for solids decomposition and odour control. Solids changes during the aerationprocess were characterized by total solids (TS), total volatile solids (TVS), total suspended solids(TSS), and total volatile suspended solids (TVSS). Volatile fatty acids (VFAs) was used to evaluatethe odour generation potential in the aerated manure. The overall TS removal efficiencies from 6.0%to 44.9%, 18.6% to 50.3%, and 42.3% to 56.4% were observed for the three different aeration levels,respectively, with reductions from 6.6% to 48.9%, 26.0% to 61.1%, and 57.3% to 69.9% for manureTVS. The ratios of TVS/TS, TSS/TS and TVSS/TS in manure were found to increase with solidslevels in the 30-day aeration process under the three aeration intensities. Reductions of BOD5reached 78.5% to 92.0%, 79.4% to 96.0%, and 91.2% to 97.0%, while reduction of VFAs reached12.7% to 99.0%, 71.7% to 99.0%, and 87.8% to 99.3%. The biodegradation of solids, BOD5, andVFAs was effectively enhanced when aeration length and level were increased. Low solids levels in manure offered a more advantageous condition for aerobic decompositions of solids, BOD5, andVFAs. Linear correlation analysis proved that the odour generation potential in manure being treatedby aeration process could be distinctly characterized by the change of solids in different forms and/orby the BOD5 levels.