Valorizing kitchen waste to produce value-added fertilizer by thermophilic semi-continuous composting followed by static stacking: Performance and bacterial community succession analysis

To explore an effective decentralized kitchen waste (KW) treatment system, the performance and bacterial community succession of thermophilic semi-continuous composting (TSC) of KW followed by static stacking (SS) was studied. A daily feeding ratio of 10% ensured stable performance of TSC using an integrated automatic reactor; the efficiencies of organic matter degradation and seed germination index (GI) reached 80.88% and 78.51%, respectively. SS for seven days further promoted the quality of the compost by improving the GI to 91.58%. Alpha-and beta -diversity analyses revealed significant differences between the bacterial communities of TSC and SS. Firmicutes, Actinobacteria, Chloroflexi, Gemmatimonadetes, and Myxococcota were dominant during the TSC of KW, whereas the members of Proteobacteria and Bacteroidetes responsible for product maturity rapidly proliferated during the subsequent SS and ultimately dominated the compost with Firmicutes and Actinobacteria. These results provide new perspectives for decentralized KW treatment using TSC for practical applications.

Automated summary

This study investigated the performance and bacterial community succession of a thermophilic semi-continuous composting (TSC) followed by static stacking (SS) for decentralized kitchen waste (KW) treatment. The TSC using an integrated automatic reactor achieved a stable performance with an organic matter degradation efficiency of 80.88% and a seed germination index (GI) of 78.51% by a daily feeding ratio of 10%. The subsequent SS for seven days further improved the compost quality with a GI of 91.58% by promoting the rapid proliferation of Proteobacteria and Bacteroidetes. The results offer new perspectives for practical applications of decentralized KW treatment using TSC.