Comparison between UV spectroscopy and Nirs to assess humification process during sewage sludge and green wastes co-composting.

The humification of organic matter during composting was studied by the quantification and monitoring of the evolution of humic substances (Humic Acid-HA and Fulvic Acid-FA) by UV spectra deconvolution (UVSD) and near-infrared reflectance spectroscopy (NIRS) methods. The final aim of this work was to compare UVSD to NIRS method, already applied on the same compost samples in previous studies. Finally, UVSD predictions were good for HA and HA/FA (r(2) of 0.

Functional changes in culturable microbial communities during a co-composting process: carbon source utilization and co-metabolism.

Microbial communities in sewage sludge and green waste co-composting were investigated using culture-dependent methods and community level physiological profiles (CLPP) with Biolog Microplate. Different microbial groups characterized each stage of composting. Bacterial densities were high from beginning to end of composting, whereas actinomycete densities increased only after bio-oxidation phase i.

Changes in the level of alkaline and acid phosphatase activities during green wastes and sewage sludge co-composting.

The aim of this work was to study the activity level of alkaline and acid phosphatases during the composting of green wastes and sewage sludge and to determine relationships between biotic and abiotic properties of compost and phosphatase activities. This study has revealed a noticeable separation of phosphomonoesterase activities into two distinct phases during composting. Alkaline and acid phosphatase activities were high during the first month of composting and then declined up to the end of the process.

Calibration of chemical and biological changes in cocomposting of biowastes using near-infrared spectroscopy.

Cocomposting of green wastes and sewage sludges is a complex process involving rapid biological and chemical changes. The objective of the study was to assess the usefulness of near-infrared reflectance spectroscopy (NIRS) to characterize these changes, as an alternative to standard procedures which are often time-consuming and laborious. Samples obtained during 146 days of composting were analyzed by 14 conventional methods and NIRS.

Efficiency of near-infrared reflectance spectroscopy to assess and predict the stage of transformation of organic matter in the composting process.

Changes in composts of sewage sludges and green wastes were analysed by near infrared reflectance spectroscopy (NIRS) and chemical analysis with 426 samples representative of six stages of composting: 8, 20, 35, 75, 135 and 180 days. Maturity of compost was assessed through changes in C:N ratio. Results of spectroscopic properties (200 wavelengths) were studied with several multivariate analyses.