Hong Kong is experiencing a pressing need for food waste management. Currently, approximately 3600
tonnes of food waste are disposed of at landfills in Hong Kong daily. The landfills in Hong Kong are
expected to be exhausted by 2020. In the long run, unavoidable food waste should be sorted out from
the other municipal solid waste (MSW) and then valorized into valuable resources. A simple sorting process
involving less behavioural change of residents is, therefore, of paramount importance in order to
encourage residents to sort the food waste from other MSW. In this paper, a sustainable framework of
food waste collection and recycling for renewable biogas fuel production is proposed. For an efficient separation
and collection system, an optic bag (i.e. green bag) can be used to pack the food waste, while the
residual MSW can be packed in a common plastic bag. All the wastes are then sent to the refuse transfer
stations in the conventional way (i.e. refuse collection vehicles). At the refuse transfer stations, the food
waste is separated from the residual MSW using optic sensors which recognize the colours of the bags.
The food waste in the optic bags is then delivered to the proposed Organic Waste Treatment Facilities,
in which biogas is generated following the anaerobic digestion technology. The biogas can be further
upgraded via gas upgrading units to a quality suitable for use as a vehicle biogas fuel. The use of biogas
fuel from food waste has been widely practiced by some countries such as Sweden, France, and Norway.
Hopefully, the proposed framework can provide the epitome of the waste-to-wealth concept for the
sustainable collection and recycling of food waste in Hong Kong.