Application of municipal solid waste (MSW) char during rotary drum co-composting (RDC) of vegetable waste and its...

Composting, a sustainable method for handling biodegradable waste constituting nearly 50% of municipal solid waste (MSW), can be enhanced by incorporating char produced from MSW pyrolysis. This study investigates the impact of MSW char (0% char-Control, 2.5% char-Trial 1, 5% char-Trial 2) on the physicochemical properties of vegetable waste compost. A thermophilic temperature range of 53.8 °C was detected in Trial 2, 50.8 °C in Trial 1, and 46.8 °C in Control. The pH of the mixes increased at day 20 to 7.5, 7.87, and 8.2 in Control, Trial 1, and Trial 2, respectively. The highest drop of total organic carbon (TOC) and volatile solids in Trial 2 is about 21.18% and 21.02%, respectively. Total Kjeldahl nitrogen (TKN) increased, particularly in Trial 2 (2.35%), while NH₄-N concentrations decreased, and phosphorus levels rose notably to 23.48 mg/kg, with 2.49 mg/kg available phosphorus in Trial 2. The C/N was reduced to 10 in Trial 2. Total potassium increase was highest for Trial 1 (6.9 g/kg). Trial 2 had the highest overall macronutrient concentration and correspondingly showed the greatest decrease in volatile solids. Furthermore, Trial 1 demonstrated a reduction in heavy metal concentration in comparison to Control and Trial 2. Consequently, the utilization of MSW char during rotary drum composting enhances the process of composting and significantly improves compost quality, making it a sustainable waste management solution.