The functional unit selected is 1 GJ of bioenergy produced from
treating dairy waste, produced during 45 days, which was the
duration of completing a scenario. Results obtained from the study,
nonrenewable primary energy requirement (GJ) and GHG emission
(kg CO2 eq.) were expressed with respect to unit of bioenergy produced.
The geographical location is the US and the simulation wasproduced) was used as an indicator for greenhouse gas emissions
or intensity. No allocation of energy or GHG was applied for the
sludge, biochar (case A and B). All impacts were allocated for
bioenergy production. Nutrients present in the sludge and manure
were taken into consideration for substituting the inorganic nutrients
through the system expansion approach (case A scenarios).
Due to negligible contribution of N, and P for plant growth from
biochar, nutrient value of biochar was ignored for the case A scenarios