Lastly, the lower variability of data on BMP tests when compared
to data from BHP (Figs. 2 and 3) should be underlined. The
standard deviation of BMP differences between the average values
and the maximum or minimum methane productions ranged
around 10% while the difference between the average values and
the maximum or minimum hydrogen potentials, was found, in
some cases, to be in the range of 200%.
This study demonstrated therefore, that the composition variability
of OFMSW affects the hydrogen potentials to a greater
extent than the methane potentials due to the different yield
achieved by the different fractions in the two fermentative
processes. This high variability of hydrogen potentials could
potentially represent a problematic issue in the management of
full-scale continuous digestion systems for the production of
biohydrogen by dark fermentation of organic waste.