Advancing Composting Needs and Options: Assessing the Co-composting Potential of Feacal Sludge and Selected Yard Waste Fractions

Abstract

Composting is a nature’s way of recycling soil conditioners and nutrients, and the value of the resulting compost depends on the efficiency of the composting process. This study sets out to investigate the effectiveness of co-composting feacal sludge (FS) and selected fractions of yard waste (YW). Laboratory-scale aerobic composting batch experiments were designed and operated according a predefined schedule for mixing and aerating (turning) the substrates for co-composting. To measure the effectiveness of the co-composting process, evolution of temperature, moisture content, pH, organic matter and nutrients were monitored through direct measurement and laboratory analysis. A maximum temperature of 63℃ (lasting for 74hours) was attained by a treatment with substrates mixed at 1:3 (FS: YW) in the first ten days of composting. The analysis of the results indicated that a mix of FS and selected yard waste fractions that forms an average initial moisture content of 63.2% and C-N ratio of 14.1 can efficiently decompose to reduce the mass of the composting substrates by at least 26% in 30 days. The results indicated further that the concentration of nutrients (N and P) and organic matter content in the co-composting substrates decreased with composting time while the measured values of C-N ratio and non-volatile solids (NVS) were increasing with increase in composting duration. Based on the physicochemical quality attained in the current study, the compost resulting from co-composting of feacal sludge and selected fractions of yards waste has a promising potential for soil conditioning.