EFFECT OF AMMONIA CONTENT IN THE BIODEGRADABILITY OF THE SALMON INDUSTRY WASTES

Lately, efforts put into solving the serious environmental problems ca used by the accumulation of liquid, gaseous or solid industrial residu es, have been greatly increased, being solid wastes the last ones to b e considered. This work studies the anaerobic biodegradation of salmon waste produced by death in the farming process. The results obtained: 61.99% degradation (expressed in volatile solids abatement), with a m ethane productivity of 535.66 1 CH4/kg(d.k.) in studies done to sample s with 1% w/v of dry residue, show that the anaerobic technology is ad equate to treat these wastes. Runs performed with higher solid content s (7, 13 and 20% w/v) showed an ammonia accumulation, coming from prot ein degradation. They represent an upper limit of the system studied a t a maximum value of ammonia nitrogen of 3.5 g/l attained, amount whic h hinders the further increase of solid matter in the tests. With the results obtained during this study, two inhibition models were analyze d (the Luong model and one proposed by the authors), which allow the p rediction of the performance of the system studied.