The application of a fed- batch operation for composting of vegetable residues

Abstract EN

The performance of fed-batch composting process of vegetable residues was studied in comparison with the batch process.

Both studies were carried out with initial ratio of tomato crop residues to grass clipping to sawdust in ratio of 1 : 2.86 : 0.29, respectively.

The mixture had initial C : N ratio of 30 : 1 and moisture content of 60 %.

The degradation pattern of organic materials was confirmed by continuously measuring the temperature, pH, total organic carbon and total nitrogen.

In addition to, microbiological pattern was studied.

In this study, the biodegradation of solid organic waste, in the fed- batch composting process, proceed without definitive thermal stages including the thermophiles phase under self -heating conditions, in comparison with batch operation.

The changes in pH of both batch and fed-batch operations were similar, exception, during the feeding stage, pH increased rapidly above 8.

The final C : N ratio of both operations was 21 and 17, respectively.

In regard to the final percentage of carbon loss of both operations were 66.8 % and 70 %, respectively.

The succession of different microbial groups showed that the fed- batch operation was different from the batch operation in that the resident microorganisms were repeatedly supplied with fresh bio waste.

Moreover, the appearance of actinomycetes growth with a grey-white at the surface of the compost is considered as an indication of compost maturing.