A Comparative Study on the Cleaner Production Options for Fishery Wastes around Lake Tana

Abstract

Around Lake Tana, there are different types of fish processing cooperatives. These cooperatives simply dump the fish wastes (offal) to the Lake Tana which results environmental pollution for the marine ecosystems. In this study three cleaner production options such as biodiesel, biogas and animal feeding were investigated experimentally for the utilization of fishery wastes around Lake Tana. The study showed that fish species (labeobarbus, tilapia and catfish) wastes have oil yield of 28.65%, 16.35% and 5.63 % and free fatty acid content of 10.5%, 7.5% and 6.03% respectively. In the treatment of the oil, only 3.5% of sulfuric acid was consumed to lower the FFA to the required level (2.5%). In the biodiesel experiment, 6:1 ration of methanol to oil and 1hr of reaction retention time were found to be the optimum operating parameters. The yield of biogas was 0.016ml /gram of fish waste. Nutritional composition of fish wastes were 33.4% protein, 0.007% fiber, 1.26% ash, 44% moisture and 21.367% carbohydrate. The study concluded that biodiesel is the possible cleaner production option among the other for the utilization of fishery wastes around Lake Tana.