fractions of food or sawdust generated during wood transformation. The second
option, the re-use, implies that the material can be utilised for the same purpose for
which it was initially conceived. It applies, for example, to the harder discarded
fractions of vegetables, which may be not suitable to be eaten directly, but can be
used in the other preparations, such as soups. Bio-waste and by-products allow a
wide range of recycling options, and their preferability strongly depends on the
material characteristics, e.g. homogeneity and composition. Lignocellulosic biomass, for example, is composed mainly by the polymers cellulose, hemicellulose
and lignin and the specific content of each of them may influence the preferable
option for valorisation [12]. Furthermore, the extraction of high-value compounds
is practicable when a homogeneous material stream is available, whereas it is hardly
feasible in case of heterogeneous streams. Among the less preferable recycling
options, anaerobic digestion was considered better than composting, because it
allows a less dissipative use of the bio-based resources, recycling nutrients and
producing methane at the same time. It has to be noted that the hierarchy could be
subjected to modifications, according to specific sustainability priorities. For
example, the maximisation of the uses for sustaining the food system may imply
giving preference to the use of food waste as animal feed, rather than to be exploited
as basis for bio-based materials.
Considering Fig. 2, “practicable” implies that the option is environmentally
preferable, technically feasible, economically profitable and compliant to
Definitions according to the European Waste Framework Directive [6]:
- waste: any substance or object which the holder discards or intends or is
required to discard;
- bio-waste: biodegradable garden and park waste, food and kitchen waste from
households, restaurants, caterers and retail premises and comparable waste from
food processing plants;
- by product: substance or object, resulting from a production process, the
primary aim of which is not the production of that item, may be regarded as not
being waste referred to in point (1) of Article 3 but as being a by-product only
if the following conditions are met:
(a) further use of the substance or object is certain;
(b) the substance or object can be used directly without any further processing
other than normal industrial practice;
(c) the substance or object is produced as an integral part of a production
process; and
(d) further use is lawful, i.e. the substance or object fulfils all relevant
product, environmental and health protection requirements for the specific use
and will not lead to overall adverse environmental or human health impacts.
Fig. 1 Definitions reported in the European Waste Framework Directive [6]
52
S. Corrado and S. Sala
option, the re-use, implies that the material can be utilised for the same purpose for
which it was initially conceived. It applies, for example, to the harder discarded
fractions of vegetables, which may be not suitable to be eaten directly, but can be
used in the other preparations, such as soups. Bio-waste and by-products allow a
wide range of recycling options, and their preferability strongly depends on the
material characteristics, e.g. homogeneity and composition. Lignocellulosic biomass, for example, is composed mainly by the polymers cellulose, hemicellulose
and lignin and the specific content of each of them may influence the preferable
option for valorisation [12]. Furthermore, the extraction of high-value compounds
is practicable when a homogeneous material stream is available, whereas it is hardly
feasible in case of heterogeneous streams. Among the less preferable recycling
options, anaerobic digestion was considered better than composting, because it
allows a less dissipative use of the bio-based resources, recycling nutrients and
producing methane at the same time. It has to be noted that the hierarchy could be
subjected to modifications, according to specific sustainability priorities. For
example, the maximisation of the uses for sustaining the food system may imply
giving preference to the use of food waste as animal feed, rather than to be exploited
as basis for bio-based materials.
Considering Fig. 2, “practicable” implies that the option is environmentally
preferable, technically feasible, economically profitable and compliant to
Definitions according to the European Waste Framework Directive [6]:
- waste: any substance or object which the holder discards or intends or is
required to discard;
- bio-waste: biodegradable garden and park waste, food and kitchen waste from
households, restaurants, caterers and retail premises and comparable waste from
food processing plants;
- by product: substance or object, resulting from a production process, the
primary aim of which is not the production of that item, may be regarded as not
being waste referred to in point (1) of Article 3 but as being a by-product only
if the following conditions are met:
(a) further use of the substance or object is certain;
(b) the substance or object can be used directly without any further processing
other than normal industrial practice;
(c) the substance or object is produced as an integral part of a production
process; and
(d) further use is lawful, i.e. the substance or object fulfils all relevant
product, environmental and health protection requirements for the specific use
and will not lead to overall adverse environmental or human health impacts.
Fig. 1 Definitions reported in the European Waste Framework Directive [6]
52
S. Corrado and S. Sala