(568f) Biochar From Wastewater Biosolids—A Comparison to Biochars From Lignocellulose

Biosolids from municipal wastewater treatment plants represent an important source of carbon and nutrients. These are typically land-applied as fertilizers so long as concentrations of biological pathogens, organic contaminants, and heavy metals are acceptable for the application sites. Biosolids consist primarily of microbial biomass with small amounts of other indigestable solids (soil, etc.) that are removed from the water through settling or filtration.

Pyrolysis of biosolids can be used to derive energy, chemicals and fuels, and biochars for land application. The heat treatment may be particularly helpful for additional destruction of biological pathogens and degradation of organic contaminants. In this study, we created a temperature series of slow pyrolysis biochars from pelletized wastewater biosolids to compare yields and properties of microbial biomass-derived biochars to those of lignocellulosic biomass-derived biochars. We used a combination of helium and solid pycnometry to measure changes in biochar porosity with temperature and feedstock. We also used scanning electron microscopy (SEM) to investigate how biomass cellular structure affects biochar pore size distribution, shape, and connectivity.