Numerical Modelling of Liquid Waste Diffusion During The Ocean Dumping Processes

• Main Authors: Lan Chia Chun, 藍家駿
• Other Authors: Chou Hsien Ter
• Format: Others
• Language: zh-TW
• Published: 1994
• Online Access: http://ndltd.ncl.edu.tw/handle/70601197410404979409

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.