Fly ash as an additive for enhancing microbial and enzymatic activities in in-vessel composting of organic wastes

Abstract

In the present study, fly ash was used as an additive for the rapid composting of biomass and kitchen waste with jaggery as an activator. The in-vessel composting experiments were carried out in ten plastic vessels of 15 L capacity containing varying amounts of fly ash, biomass waste, and kitchen waste. The effect of fly ash on the microbial and enzymatic activity of the composting system was also ascertained. The compost in Vessel No. 10 having a combination of 50% biomass waste, 30% kitchen waste, and 20% fly ash seemed to have a significant effect on the compost quality. Statistical analysis revealed Vessel No. 10 as significantly separated from other vessels whereas microbial activity (342.67 CFU 108/g), pH (8.15), temperature (48.50 °C), and heavy metals, such as Ni (0.1239 mg kg−1), Ba (0.6109 mg kg−1), Cd (0.0004 mg kg−1) were the most influential variables for the separation.