Methane Production from Farmed Rainbow Trout Byproducts by Anaerobic
Digestion in Morocco

Fish are a staple in human nutrition because of their great nutritional and dietetic value. The processing stages of these fish before being sold generates an important quantity of byproducts (head, viscera, skeleton, fins, scales, tail, and skin). This study aims to determine the methane production, methanogenic potential and the percentage of volatile solids removed by the anaerobic digestion process. The experiment was carried out at mesophilic condi - tions in a Continuous Stirred-Tank Reactor (CSTR) with a discontinuous feeding mode (batch). The results ob - tained showed that the byproducts of farmed rainbow trout have a maximum methane production 1176 Nml whose methanogenic potential is 206.68 Nml/gVS with a biodegradability equal to 57.95%. For the kinetic modeling, four models were applied for an adequate fit of the experimental results (first order, MGompertz, transfererence function, and logistic function). The production of methane closest to the experimental results is that estimated by the logistic function with a methanogenic potential of 212.21 Nml/gVS whose correlation coefficient R 2 = 0.9870 and a very low percentage of error (1.18%), also the MGompertz model presented results adapted to those of the experiment with a methanogenic potential equal to 223.61 Nml/gVS ( R 2 = 0.9889 and %error = 2.95); This con - firms that these two kinetic models are the most suitable for this type of substrate.