| Summary: | 碩士 === 國立中央大學 === 土木工程研究所 === 82 === River contamination has become a serious problem in Taiwan
area, since the waste material is dumped into rivers without
any previous treatment during the past time. Ocean dumping of
the low hazardous waste liquids is a feasible solution for
this problem, because the liquid pollutant could be diluted by
the vast amount of ocean water which surrounds Taiwan.
This study applies theory of diffusion and its numerical
method to analyze the diffusion characteristics in ocean
dumping of liquid waste. Diffusion of liquid waste in method
of instantaneous fixed - point dumping and barge - wake
discharging are discussed respectively, diffusion process in
instantaneous fixed-point dumping could be categorized into
three phase:(1) convective descent phase, (2) dynamic collapse
phase, (3) long-term diffusion phase. Barge-wake discharging
is also categorized into three phases : (1) near-wake dilution
phase, (2) far-wake dilution phase, (3) long-term diffusion
phase. This study focus on the assessment of covered area,
submerged depth of liquid waste and dilution value of its
concentration in various phases of diffusion, and the
discussion of the various impact on diffusion process of
liquid waste due to different method of dumping operation.
Instantaneous fixed-point dumping is examined by both of
theory and numerical model in this study, we find that density
stratification of ambient water and water depth are important
influential factors in this operation. Speed of the barge
is the most important influential factor in the barge-wake
discharging. Results of wake-dilution modelling and the field
observation data are in good agreement, while the IMCO formula
underestimates the dilution rate.
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