Biowastes (BW), the main raw materials for the composting installations in developing countries, are characterized for
containing uncooked food wastes (FW), high moisture content, low porosity, acidic pH, and low C/N ratios which affects
the overall composting process (CP). In this study, we evaluated the effect of adding sugarcane bagasse (SCB) and star grass
(SG) (
Cynodon plectostachyus
(K. Schum.) Pilg.) as bulking materials (BM) over the quality of the substrate, progress of
the process, and quality of the obtained product. In this sense, two pilot-scale experiments were performed. The first one
contained a substrate formed by 78% BW and 22% SCB (pile A). The second experiment contained a substrate formed
by 66% BW and 34% SG (pile B). For each experiment, control treatments (piles A´ and B´ respectively) were performed
by using 100% BW without BM. The results showed that in both cases the adding of BM improved substrate quality
(pH, moisture, and total organic C content [TOC]), speeding up the starting step (2-3 d) and reducing the duration of the
thermophilic phase of CP (3 d). However, the physico-chemical properties of both BM increased cooling and maturation
phases duration (between 15 and 20 d). Obtained products quality was improved in terms of higher TOC, cation-exchange
capacity, bulk density, and higher water holding capacity. Application of obtained products A and B could improve some
soil properties like major nutrient, water retention, and increasing the organic matter.
