Table 3 shows the determined physiological and chemical
properties of the sampled wastewater. It was found that
the heavy metal levels, as well as the pH, conductivity,
temperature and COD, were not significantly different between
biogas and non-biogas swine farms. However, BOD
and coliform levels on biogas farms were significantly
lower (p < 0.01 and p < 0.05, respectively) than in the
wastewater from non-biogas farms.