Abstract
ABSTRACT. Composting is an efficient technique for managing the increasing production of organic wastes since it transforms them into a valuable product that can be applied to soil to improve it. However, it is necessary to ensure the adequate properties of this product for a proper agricultural or environmental application. Various parameters have been proposed as estimators of the evolution of the composting process, nevertheless there is a lack of easy techniques with a wide application range for monitoring it. This study evaluated some parameters that can be used to test compost evolution in samples of composted sewage sludge under full-scale conditions. Total extractable carbon (TEC) by alkaline solution of sodium pyrophosphate, humic acids (HA), fulvic acids (FA), and the ratio of them (HA/FA) were obtained by a one-step extraction procedure. Results were compared with those obtained after an official extraction method for the same parameters. Total organic matter was calculated by calcination (TOM%). The objective was to assess the usefulness of the one-step extraction as an easy and cheap tool for monitoring the composting process. The results indicate that both extraction procedures show a statistically significant correlation between them and with TOM%. Therefore, TEC obtained by the one-step extraction procedure can provide useful information about the evolution of the composting process of compost samples with the easiest methodology.
ACKNOWLEDGMENTS
B. Temporal-Lara gratefully acknowledges the Spanish Ministry of Education, Culture and Sports for a research fellowship (FPU 12/00429). The authors would like to thank “FACSA S.A.” for providing the compost samples.