| 摘 要： |
Insufficient O-2 concentration in the matrix pores, which is adjusted by air-immobile regions in compost piles, is a main factor in forming anaerobic cores in compost particles and then generating harmful off-gases during composting. However, it is unclear how the change of air-immobile regions affects temporal variation of O-2 in the pores during the whole composting process and after turning. In this study, we first used a tracer-inverse calculation protocol to obtain feature parameters (first-order gas transfer coefficient, which expresses gas transfer from air-mobile regions to air-immobile regions, alpha; volume proportion of the air-immobile region, phi) of the air-immobile regions in the matrix pores before and after turning during whole composting process, and then predicted the temporal variation of O(2)in the pores using two-region model with these measured parameters. The alpha values were 0.0017/0.0011, 0.0012/0, 0.0048/0.0001, and 0.0048/0.0001 min(- 1), respectively, while the corresponding phi values in initial-material, temperature-increasing, thermophilic, and curing phases were 0.36/0.40, 0.40/0.43, 0.45/0.46, and 0.48/0.57 before/after turning, respectively. The value of alpha declined throughout composting process after turning. The proportion of air-immobile regions in the temperature-increasing and thermophilic phases was higher than that in the curing phase. The air-immobile regions caused difference of predicted O-2 concentrations between air-mobile and air-immobile regions. The phi was increased as composting process. Turning piles slightly change phi except in curing phase, while it caused increases in phi during this phase. These findings provide support for reducing the production of harmful off-gases in composting. |
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