Fish wastes to fish oil

Overview on the whole valorisation process from fish wastes to energy

Figure 1: Possible implementation for the fish wastes-to-oil separation unit 

Oil separation solution to get the value out of fish waste

Fish oil is extracted from the fish wastes through a separation process.

The separation divides pre-treated fish waste into three fractions: fish oil, protein and water. Oil will be used for methyl ester (biodiesel) production. Protein can be fed into an aerated composting drum together with support material to produce compost soil (see Biodiesel by-products). The compost from the composting drum is matured and cooled down before utilisation. The Waste Water from the process is treated in a Waste Water Treatment Plant (WWTP).

Figure 2: Fish oil production inputs and outputs at Hiep Thanh Seafood

Fish waste is crushed in a mechanical crusher and treated with ~2 to 5% formic acid for suspension purposes. The suspension is heated up and let stand still in a certain temperature (according to local hygienization requirements). The separation after crushing and pre-treatment happens by gravity: oil as lightest phase floats, whereas the heavier water falls at the bottom and protein stabilizes in between. The liquid fraction contains oil and water, which are further separated by mechanical centrifugation. The solid protein fraction (Total Solids (TS) ~25%) is then utilized for post-treatment depending on the foreseen end use (see Biodiesel by-products).

After the oil is separated, it is fed into the biodiesel processor to produce biofuel.

The Input capacity of the Fish Power solution is 45 tonnes of fish wastes / day. At such a capacity, no external energy is needed for the process. The solution only needs cold water and electrical connections.

PRESECO’s design solution

Figure 1: Possible implementation for the fish wastes-to-oil separation unit