Nile perch fish processing waste along Lake Victoria in East Africa: Auditing and characterization
Worldwide, fish industry wastes are an important contaminant having an impact on the environment. The recovery of value added products from these residues constitutes an important waste reduction strategy for the industry. In East Africa, Nile perch fish processing into chilled fish fillet for export along Lake Victoria generate large proportions of both solid and liquid wastes. However, no thorough auditing and characterization of the waste has been done that would guide potential value addition through bioconversions and waste management. Auditing by surveying and mapping the fish processing industries was conducted along the lake. Waste quantification was done using specific guidelines for assessment of fish wastes. Analysis of the waste was carried out using standard methods. Annual solid waste and wastewater generation was estimated at 36,000 tonnes and 1,838,000 m3, respectively. The wastewater generated was high strength with a total chemical oxygen demand of 12,400 mg/l and solid content of 5,580 mg/l. The wastewater contained 6,160 mg/l of lipids and 2,000 mg/l of protein. The Nutrient content was 20 mg/l of total phosphorous, 340 mg/l organic nitrogen and 61 mg/l of ammonia nitrogen. The current fish waste management systems in place were found to be neither efficient nor profitable, thus profitable options of fish waste utilization and waste reduction strategies are imperative. Modern and economically viable options of fish waste value addition, decision scheme and waste reduction strategies have been highlighted in this paper. In conclusion, large amounts of fish waste generated are a rich source of lipids and proteins, which could be utilized for production of value added products through bioconversions.
Key words: Nile perch, fish waste, auditing, characterization, value addition, utilization.