Investigation of biosolid-compost produced by high-temperature fermentation process

Abstract

Disposal of biosolids has been paid a due attention in Taiwan owing to their increasing amounts in the recent years. As there is no special landfill for biosolids dumping in Taiwan, transformation of biosolids to compost could be one of the suitable means of disposal. The study aimed to investigate the use of high-temperature fermentation technique to produce biosolid compost and examine the quality of bio-solid compost produced. Biosolids collected from a municipal wastewater treatment plant were treated by electro-kinetics to remove heavy metals and mixed with some agricultural wastes (mushroom waste and chicken excreta) to transform into the compost by a high-temperature (130°C) fermentation process. Prior and post to fermentation, the concentration of heavy metals and pathogenic bacteria in the biosolid-compost were determined. Results indicated that concentration of Cd, Cr, Cu, Ni and Pb in the compost after fermentation was within the soil control standard of Taiwan EPA. The pathogenic bacteria such as Escherichia coli, Salmonella, and parasitic ova in the final compost were within the government criteria. Biosolid compost was then applied as a soil improvement material to compare the relative growth (with a control) of red leaf shovel within the campus premises. The plants in the plot with biosolid compost demonstrated a better growth than the same plants in the control.