Biodegradation of Lignocelluloses inSewage Sludge Composting andVermicomposting

Aims of the Study: The aim of this study was to determine the amount of lignindegradation and biodegradation of organic matter and change of biomass undercompost and vermicomposting of sewage sludge.Materials & Methods: Sawdust was added to sewage sludge at 1:3 weight bases toCarbon to Nitrogen ratio of 25:1 for composting or vermicomposting. Lignin andvolatile solids were determined at different periods, of 0, 10, 30, 40 and 60 days ofcomposting or vermicomposting period to determine the biodegradation oflignocellulose to lignin. Results were expressed as mean of two replicates and thecomparisons among means were made using the least significant difference testcalculated (p <0.05).Results: After 60 days of experiment period, the initial lignin increased from 3.46% to4.48% for compost and 3.46% to 5.27% for vermicompost. Biodegradation oflignocellulose was very slow in compost and vermicompost processes.Vermicomposting is a much faster process than compost to convert lignocellulose tolignin (p <0.05).Conclusions: The organic matter losses in sewage sludge composting andvermicomposting are due to the degradation of the lignin fractions. By increasingcompost age, the amount of volatile solids will decrease.