Revaluation of Maturity and Stability Indices for Compost

BOD/COD ratio of compost was studied in conjunction with C/N ratio as commonly maturity index. Carbonaceous materials as well as nitrogenous materials declined in open-air conditions during 20 weeks. C/N ratio was correlated with BOD/COD, a couple parameters to qualify the compost was mature and stable. This study came up to the conclusion that compost maturity with C/N of less than 14 instead of less than 20 was corresponding to stability with BOD/COD of less than 0.1. Additional assurance on maturity and stability was carbon dioxide emission rate of less than 2 mg C/g VS/day.