2. Material and methods
2.1. Wastewater characterization
During the period of the biological tests, 110 L of wastewater from a fish canning industry of northern
Portugal were collected at each time and left to settle for 1.5 h. DOC and total soluble nitrogen (Ntotal
soluble) of each effluent sample were determined following the Standard Methods for the Examination
of Water and Wastewater [18]. DOC was determined by using Total Organic Carbon analyzer (5000 A
analyzer from Shimadzu, Japan). The values reported represent the average of at least two
measurements; in most cases each sample was injected three times, being the validation performed
by the apparatus only when coefficient of variation (CV) was smaller than 2%.