Abstract

Thermophilic composting is commonly used for the treatment of organic wastes or for production of organic/natural fertilizers. Vermicomposting (V) is also increasingly becoming popular. These two techniques have their inherent advantages and disadvantages. In this study, vermicomposting and a combination of thermophilic composting and vermicomposting were compared as ways of sanitizing and biodegrading dairy manure and waste paper mixtures with C:N ratios of 30 and 45. Wastes with a C:N ratio of 30 proved more suitable for both vermicomposting and combined thermophilic composting and vermicomposting as their composts were more stabilized and with higher nutrient contents than composts made from wastes with a C:N ratio of 45. Both vermicomposting and combined composting and vermicomposting were effective methods for the biodegradation of dairy manure and paper waste mixtures with C:N ratio of 30 but the latter was more effective in the biodegradation of waste mixtures with a C:N ratio of 45. Combining therrmophilic composting and vermicomposting eliminated the indicator pathogenEscherichia coli 0157 from the final composts whereas vermicomposting only managed to reduce the pathogen population.

Key words: Biodegradation, C:N ratio, dairy manure, Eisenia fetida, Escherichia coli 0157, humification index, composting, vermicomposting, waste paper.

Abbreviation

HR, Humification ratio; HI, humification index; MC, moisture content; CV, combined vermicomposting; C_HA, extractable humic acid carbon; C_FA,extractable fulvic acid carbon; EC, electrical conductivity; VS, volatile solids; C_EX,extractable carbon fraction.