The Application of a Fed Batch Reactor for Composting of Vegetable and Fruit Wastes

The performance of fed batch composting on vegetable and fruit wastes were studied in comparison with the batch reactor. Four waste feeding rates were studied in the fed batch reactor and three ratios of waste and sawdust were studied in the batch reactor. Both studies were carried out with an aeration rate of 10.62 | m-3 min'I. The optimum rate of waste for a fed batch reactor was 21.23 kg m-' day-' where the highest percentage of dry mass loss and the shortest composting time were achieved. The maximum constant rate (k=0.0028 day 1) of batch composting was obtained under an initial ratio of waste to sawdust of l:1.50 (w w-'), whereas an initial ratio of waste to sawdust of 1:0.15 resulted in the development of anaerobic conditions within the reactor; consequently, the rate of waste degradation was the lowest (k = 0.0007 dayl;. Within 36 days the fed batch reactor could decompose 4 times more wastes than the batch reactor within the same operating conditions. It was found that the constant rate of batch and fed batch composting of vegetable and fruit wastes can be described by a first-order model.