Abstract
Turning operation and adjusting of moisture content are indispensable process in the composting of tree pruning chips. From our previous study, reduction of the composing period to 90 days was observed as a result of the 60% moisture control by turning operation. Moreover, the higher aeration rate required higher amount of additional water by turning operations.
In this study secondary crushing process of pruning chips were examined to simplify composting methods without turning and adjusting of moisture content in 1m 3 reactors equipped with air pipes. Three aeration conditions were also examined to seek suitable methods for a moisture control. A flywheel cutter type chipper was used for the primary crushing and screw pressure type crusher was used for the secondary crushing. The aeration conditions of reactors were the continuos aeration, the intermittent aeration (30 minuets on and 60 minuets off) and the daytime aeration (8 hours during daytime on and 16 hours off) reactors and aeration rates were 15m3/day.
The results were followings:
1) The moisture contents of secondary processed chips held above 40% during more 56 days in composing process.
2) Secondary crush chips with the intermittent aeration fermented without turning operations.
3) The intermitting aeration reduced the composing period to 56 days.
4) The fermentation temperatures did not reach to suitable range in the daytime aeration reactor.
