Fate of carbon in composting process

© Springer Japan KK, part of Springer Nature 2019. All rights reserved.In this chapter, the activity of microorganisms in the composting toilet during the degradation of feces is presented through the quantification of reductions in total solids (TSs), volatile solids (VSs), and chemical oxygen demand (COD) during batch tests in laboratory-scale composting reactors. TS, VS, and COD reductions are on the order of 56, 70, and 75%, respectively, irrespective of the organic loading regarded. Characterization of organic matter attending biodegradability is a common practice when a bio-kinetic model is used to describe the reaction rates at which organic matter of wastewater is biodegraded. This chapter deals with the transformation of organic matter contained in feces as an indicator of the fate of carbon in composting process; two approaches for evaluating the transformation of organic matter of feces are discussed based on physicochemical determinations and biological response during aerobic degradation. Application of those procedures led to the description of feces organic matter transformation in terms of chemical oxygen demand (COD) and mass units.