The challenge to minimise the volum

The challenge to minimise the volume and the waste mass in a
small-scale composting system conducted to build an innovative
experimental setup including six instrumented reactors functioning
in parallel. This work aimed to confirm that this device reproduced
the composting process and that the final compost was
comparable to those generated by full-scale composting plants.
The performance and reproducibility of composting was investigated
on a mixture of sewage sludge and green wastes standing
as example of classically used initial waste mixture. The establishment
of thermophilic conditions by self-heating succeeded in all
reactors. The losses in TOM over the whole process were similar
to large-scale reactors or on-site experiments. A classical stabilisation
of compost organic matter corresponding to the enrichment
in the LIC fraction and a decrease in the biodegradable fractions
was observed. Nevertheless, the lignin degradation was less
important than in full-scale systems probably related with the
shorter thermophilic phase, essential for lignin degradation, and
the lack of screening that sorts coarse LIC and CEL-rich fractions.
The composting process in the small-scale reactors was highly
reproducible for maximum temperature reached through selfheating,
dry matter and organic matter losses and compost organic
matter stabilization and biochemical transformations. Despite
the inherent difficulties of the miniaturisation of the composting
process, the small-scale reactors and the composting procedure
performed representative composting. It could be used in further
studies on the degradation of organic pollutants during composting
using radio-labelled molecules requiring small amounts of initial
mixtures.
Acknowledgements