Zygmunt Usydus and Piotr J. Bykowski
Sea Fisheries Institute, Kołłątaja 1, 81-332 Gdynia, Poland

Key words: protein, fish oil, post-coagulatory residue, feed, methane, energetic purposes, hydrolized protein, fish meal.

Abstract.
The results of research on possible utilization of proteins and fats contained in wastewater from the fish processing industry are presented. The ways of utilization of organic substances contained in wastewater, in relation to chemical characteristics of non-treated raw wastewater and the used treatment method, are proposed. The possible exploitation of valuable substances contained in wastewater for feed and energetic purposes is considered. The preliminary feeding experiments with feeds obtained from post-coagulatory residues, conducted at the Institute of Zootechnology in Krak�w, indicate that proteins isolated from wastewater can be utilized for feeding livestock.