Calculator Tool for Determining Greenhouse Gas Emissions for Biosolids Processing and End Use

A greenhouse gas (GHG) calculator tool (Biosolids Emissions Assessment Model, BEAM) was developed for the Canadian Council of Ministers of the Environment to allow municipalities to estimate GHG emissions from biosolids management. The tool was developed using data from peer reviewed literature and municipalities. GHG emissions from biosolids processing through final end use/disposal were modeled. Emissions from nine existing programs in Canada were estimated using the model. The program that involved dewatering followed by combustion resulted in the highest GHG emissions (Mg CO2e 100 Mg−1 biosolids (dry wt.). The programs that had digestion followed by land application resulted in the lowest emissions (−26 and −23 Mg CO2e 100 Mg−1 biosolids (dry wt.). Transportation had relatively minor effects on overall emissions. The greatest areas of uncertainty in the model include N2O emissions from land application and biosolids processing. The model suggests that targeted use of biosolids and optimizing processes to avoid CH4 and N2O emissions can result in significant GHG savings.