Composting of stabilized municipal sewage sludge with residues from agri-food processing in Poland

Abstract

Stabilized municipal sewage sludge and selected waste from agri-food processing can be used for agricultural purposes, which is part of the circular economy. Therefore, chosen residues were tested for the possibility of using them for fertilisation purposes. They were then subjected to the process of composting in a bioreactor with artificial aeration. The compost mixtures were prepared to take into account their contents of, among others, carbon, nitrogen, phosphorus, and water; in the case of sewage sludge, the contents of biological contaminants and heavy metals were also determined. Based on the conducted studies, it has been found that organic waste from agri-food processing and stabilised municipal sewage sludge can be used in the composting process. At the same time, the obtained compost is characterised by good fertilising properties. Considering the physicochemical properties of the obtained compost, it was found that it can be a precious fertiliser used as a soil additive.