Food Waste and Catering Waste; Focus on Valorisation of Used Cooking Oil and Recovered Triglycerides - The Economic Utilisation of Food Co-Products - page 89

Table 6.1 Description of animal by-products.

Category/risk Definition/type of waste Prescribed treatment

Category 1
(Very high risk)

Animal parts or animal types
nonsuitable for human
consumption (carcasses and
BSE/other disease-infected
materials)

Destruction is by incineration
Recovery of valuable
components for fuel
applications, (rendered fat) 20

d n 9 r 3 n g | 0

Category 2
(High risk)

Dead animals
Manure and digestive material
Other material different to
category 1 and 3.

Biological treatment
Anaerobic digestion 21
Recovery of valuable inorganic
and organic components 22

d y y f n n 3 .

Category 3
(Low risk)

Suitable for human
consumption but discarded
for commercial reasons
(packaging, wrong transport,
expiry date, etc.)

Recovery of valuable
components for a range of
applications: pet food, biofuel
production and cosmetics

and composition but are generally highly polluting (e.g. blood, fats,
and residues from intestines, partially digested grass or manure). In addition,
industrial processing water is discharged as a liquid euent that may have
high nitrogen content or high levels of BOD/COD (biological and chemical
oxygen demands, respectively). Various treatments for pathogens and
pollutant removal are required for these streams, with common processes
including thermal, biological or chemical treatments. 19 For some animal
by-products, it may be challenging to develop routes towards recycling or
reutilisation due to health and environmental concerns. The regulation on the
use of animal derived byproducts is very strict in the EU, establishing three
different categories which determine the end use of such coproducts (Table 6.1).

6.3 Characterisation of UCO and Triglyceride-Rich
Food Waste
Frying oils mainly comprise triglycerides, monoglycerides, diglycerides and
variable quantities of free fatty acids (FFA; 5-20% w/w), generated during the
frying process. 23 Rendered fats contain variable amounts of FFA and are
semi-liquid/solid at room temperature.
As with any material to be employed as feedstock its specification, physical
and chemical properties are of key importance. The composition (free fatty acid
content, moisture, impurities and fatty acid profile mainly) will determine the
aptitude of various recovered fats and oils to be employed in various
application.
Therefore understanding the specification of UCO and recovered fats is of
critical importance alongside the need for standardisation, aiming for the
recovered fats and oils to be employed as a consistent feedstock for various
fuels and chemicals.