Possibilities to use fish waste for energy production

Abstract

The secondary raw materials of fish can be used for various purposes in food industry, agriculture, etc. No less important way for usage of secondary raw fish, dead fish and fish farming sludge is the utilization of mentioned feedstocks for energy purposes, i.e. biofuels production. In this reearch, the possibilities of the consumption of dead fish and fish farming sludge for biodiesel and biogas production has been studied. The influence of the basic biodiesel production parameters, including the methanol to oil molar ratio, amount of catalyst, temperature and process duration on transesterification yield was determined. The guantitative and gualitative research of biogas production using different substrates such as fish waste, fish farming sludge and substrates composed of fish waste (de-oiled and non de-oiled biomass)+fish farming sludge and fish farming sludge+wastewater sludge was performed. The biodiesel yield higher than 96.5% could be achieved under the following process conditions: methanol/oil molar ratio – 4:1, amount of enzyme content – 7% from oil mass, temperature – 40 ° C, reaction time – 24 hours. The highest biogas yield (1224 ml/gVS) was determined using wet fish waste biomass and mixed substrates consisted of fish waste and fish farming sludge. The results of qualitative biogas research revealed, that biogas produced from both homogeneous and heterogeneous substrates contained more than 60% of methane. The highest calorific value (app. 70% of methane) had biogas gained from fish waste biomass.