A
linear relationship for the total biogas volume produced
with the milk content in the manure was revealed, with
a correlation coefficient of 0.99. An improved removal
efficiency of chemical oxygen demand was observed for
milk-treated digesters. Good linear regressions between
the total biogas production and the percent chemical
oxygen demand decrease and the substrate carbon/nitrogen
ratio were also obtained (correlation coefficients:
0.93 and 0.99, respectively)