THERMOGRADIENT RESPIROMETRY AS A TOOL FOR MEASURING COMPOST STABILITY

The composting process of olive press cake (OPC) was studied using a thermogradient respirometer developed in our laboratory.
This apparatus determines the respiratory profile of an organic substrate over a wide temperature range.
The composting experiment took place over a period of five months during which the material was re-moistened for nine times.
The composting process resulted in detoxification of the olive press cake, as indicated by seed germination tests.
The pH and conductivity of the compost initially increased but only the pH resulted in higher final values.
The Ratkowsky equation was tested as a model for describing the variation of the decomposition rate during the composting process.
The underlying hypothesis is that during composting, the microbial population is homogenous as regards its respiration, and adapted to the composting temperatures.
The validity of the model was examined by fitting the equation to the respiration data obtained by the thermogradient respirometer.
A stability index was derived, which adequately described the stabilisation of the material during the composting process.

International Symposium on Composting of Organic Matter

I.S. Mari, M.G. Kotsou, C. Ehaliotis, D. Georgakakis, C. Balis

composting, compost stability, respiration, thermogradient respirometer, Ratkowsky

https://doi.org/10.17660/ActaHortic.2001.549.9