Chemical Characteristics of Biosolids Composted with Eucalyptus Bark.

Biosolids contains organic matter and nutrients and can be applied in agricultural and forestry lands as organic fertilizer, as long as it respects the tolerance limits for pathogens indicators. When mixed with a carbon source, it causes elevation of temperature through the composting process, whose principle is the transformation of organic matter by aerobic microorganisms. In the thermophilic phase of composting, the temperature of the compound mass increases to the range of 40 to 70 °C, which, in addition to the degradation and stabilization of organic matter, reduces and eliminates pathogens. Thus, the objective of this study was to analyze the use of eucalyptus bark as a carbon source in the composting process with two different type of biosolids: one from Upflow Anaerobic Sludge Blanked Digestion (UASB) and other from a prolonged aeration activation process. Both biosolids were mixed with eucalyptus bark in a 1:1 volumetric ratio and were kept in the composting process for 45 days. By the end of 45 days, there was a decrease in temperature and moisture indicating a decrease in microbial activity.