Js. Vandergheynst et al., HIGH-SOLIDS AEROBIC DECOMPOSITION - PILOT-SCALE REACTOR DEVELOPMENT AND EXPERIMENTATION, Process biochemistry, 32(5), 1997, pp. 361-375
Pilot-scale reactors have been constructed to mimic the central core o
f an aerated static bed or in-vessel composting process. The 770 litre
reactors were instrumented to measure temporal and spatial variations
in temperature, oxygen and moisture content. Experiments were perform
ed with a synthetic food waste (SFW) and digested biosolids using four
different aeration rates and two initial moisture contents. An analys
is of the temporal and spatial temperature and oxygen profiles has sho
wn the systems replicate well and represent a process with one-dimensi
onal spatial variation. An analysis of oxygen gradients has shown that
cumulative oxygen depletion and oxygen depletion rates within the bed
increased with increasing aeration rate in the SFW experiments, howev
er, they decreased with increasing aeration rate in the biosolids expe
riments. The SFW studies showed that a 10% variation in initial moistu
re content had little influence on cumulative O-2 consumed, but had a
significant influence on the location of maximum biological activity w
ithin the bed. Maximum temperatures varied from 58 to 74 degrees C in
the SFW experiments and from 43 to 60 degrees C in the biosolids exper
iments. In all experiments the maximum temperatures and the positions
where they occurred varied with initial moisture content and aeration
rate. In the SFW experiments maximum axial temperature differences coi
ncided with significant axial differences in moisture content, while i
n the biosolids experiments maximum axial temperature differences coin
cided with minimal axial differences in moisture content. (C) 1997 Els
evier Science Ltd.