Aerobic composting and vermicomposting of durian shell and citrus peel wastes

Aerobic composting and vermicomposting processes were compared in the co-composting of durian shells and citrus peels. For decomposers, the microorganism catalyst from the Land Development Department, i.e., the LDD1 catalyst, and earthworms were used. The moisture contents of the durian shells and citrus peels were 84.6% and 77.3%, respectively, and the pH of the shells and peels were relatively low, as these are sources of potassium. The experiments utilized four different reactors: durian shells (100%) in reactor 1; durian shells and citrus peels (50% to 50% ratio) in reactors 2 through 4; with the LDD1 catalysts in reactor 3 and the earthworms in reactor 4. The temperature, pH, moisture content, electrical conductivity, NaCl, organic matter, organic carbon, C to N ratio, nutrients (nitrogen, phosphorus, and potassium), germination index, and size of the compost were analyzed according to the standards of the Land Development department (2013). Throughout the composting process, the pH tended to increase, although citrus peels, with a low pH of 3.95, were used as a raw material. At the end of the composting process, reactor 4, which used earthworms as decomposers, passed the standard criteria, yielding a germination index of 90%.