482 MARINE PRODUCTS OF COMMERCE 



Centrifuge System. There are two types of centrifuges used in the separation 

 of press hquor into its component fractions. The first is a 3-phase machine designed 

 to separate oil, water, and some suspended material. The solids and some water 

 are discharged from one port, the oil containing a small amount of water as an 

 emulsion from a second port, and the remainder of water from a third port. The 



(Louriesy ^naipmi i^oip.) 



Fig. 22-9. Battery of Nozljectors for separating oil, water, and suspended 



protein material. 



oil emulsion is passed through a second centrifuge, termed an oil purifier, for a 

 complete separation of the oil and water. After passing through the second centri- 

 fuge the oil is ready for market. The water from the oil separation is returned 

 to the receiving tank in which water from the first separation is stored. The solids 

 are separated by the screen or filter system just referred to. 



Condensation of Press Water. The water fraction from the above separations is 

 knowTi as "stickwater" or fish "solubles," and contains minerals, vitamins, amino 

 acids, and many other valuable nutritional ingredients. When dumped into pub- 

 lic waters this waste product becomes a nuisance. Because of its nature it putrifies 

 easily and gives off revolting odors. Since it contains proteinaceous compounds, 

 it is an excellent medium for bacterial growi:h, and thus may become a public 

 health hazard. For many years fish meal manufacturers failed to recognize the 

 potential value of this waste product when properly condensed and mixed with 

 cattle and poultry feeds. After years of study and experimentation the present 

 process was developed. 



