Abstract:
Rice is the most popular food in Sri Lanka where approximately 70% of the paddy
production goes through the parboiling process. Parboiling process is a hydrothermal
treatment method. This treatment process consumes energy, water and other environmental
resources and adds air and solid emissions, effluents and wastages back to environment
which cause adverse environmental impacts. Total environmental input and output emissions
of the parboiling process depend on the selected treatment method and the type of equipment
used. Therefore the total environmental effects of each and every step in the life cycle of the
production process needs to be considered in order to identify the most environmental
friendly paddy parboiling method.
The overall objective of this work is to assess environmental impacts of different parboiled
paddy production methods adopted in Sri Lanka by using life cycle assessment (LCA)
approach. LCA is a methodological context to estimate the environmental effects caused by
the life cycle of a product, service or process. Goal and scope definition, life cycle inventory
analysis, life cycle impact assessment and interpretation are the four major steps in LCA
methodology.
The environmental performance of three parboiling methods named as modern method with
hot soaking and mechanical drying, modern method with hot soaking and sun drying and
semi modern method with cold soaking and sun drying were assessed and compared
quantitatively and qualitatively. Processes from paddy harvesting to rice cooking are
included in the system boundary.
According to the results, highest impact of parboiled rice production is given by the cooking
step. The highest impacts from cold soaking operation method were observed in
eutrophication, depletion of abiotic resources and climate change impact categories. The hot
soaking method resulted highest impacts on human toxicity, photo oxidant formation and
acidification.
