The main objective of the present study was to provide a comprehensive LCI of medium scale composting of food waste
and yard waste at institutional level, based on substance flow analysis (SFA). A secondary objective was to present the
composition and assess the quality of the final compost product from composting of typical Asian organic waste (food
waste and yard waste). The experiments were designed to represent a batch situation in an institutional medium size
composting scenario with input material of food waste mixed with grass clippings and dried leaves. Two composting
runs were carried out with the intention to showcase the heterogeneity of organic waste and study the effect of windrow
size on the performance of the process. The input and output material were sampled and characterized in order to
quantify the substance balance of the process. SFA was performed by means of the mass balance model STAN 2.5 to
compute unknown parameters (gaseous emissions). SFAs have been performed for C, N, K, P, Cd, Cr, Cu, Ni and Pb. The
composting windrows were fed with 212.4 and 393 kg, respectively. VS content reduction is greater in composting pile
with larger size (Run 2). The loss of C during composting was recorded in the range of 0.146-0.166 kg/kg ww. The C
losses via leachate were insignificant (0.02% of the total input C). The total N loss during the process was 0.005-0.012
kg/kg ww. The leachate generation was measured as 0.012-0.013 kg/kg ww. The flows of selected heavy metals were
assessed. Heavy metals were of minor significance due to low concentrations in the inputs (food waste and yard waste).
Heavy metals were found to be released to the atmosphere. However, majority of heavy metals remain in the finished
compost. The C/N reduction during the process was in the range of 10-23%. In general, the compost composition was
considered to be within the ranges previously reported in literature and thus ready for application in gardening. The LCI
presented in the present study can be used as a starting point for making environmental assessments of medium-scale
co-composting of food waste and yard waste in tropical environment. No major environmental problems were identified
from the process, except for the emissions of GHGs.