Lead contamination in drinking water : Release and hydrodynamic behaviors of lead corrosion products
| Autor: | Yu-Cheng Peng, 彭昱程 |
|---|---|
| Rok vydání: | 2018 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 106 Lead is a serious threat to human health and its exposure via drinking water consumption has long been overlooked. It has been found that particulate lead contributed significantly to drinking water lead concentration and possessed the highest risk in recent contamination incidents. The hydrodynamic behaviors of particulate lead, however, are largely unknown. In this study, lead pipe flushing experiments, microscopic observations and computational fluid dynamics (CFD) were employed to investigate the release and hydrodynamic behaviors of lead corrosion products commonly found in distribution systems. In lead pipe flushing experiments, new lead pipes conditioned solutions with different compositions in order to form four different commonly observed corrosion products, namely cerussite (PbCO3), hydrocerussite (Pb3(CO3)2(OH)2), chloropyromorphite (Pb5(PO4)3Cl), and plannerite (β-PbO2) were prepared. The pipes were then flushed under different flow rates (1-10 L/min). It was found that the particulate lead concentration increased with the increasing flow rates for cerussite, chloropyromorphite and plannerite. For hydrocerussite, water flow rate had a minimal influence likely due to its smooth surface morphology. In the microscopic observation using a digital microscope, the detachment of cerussite particles was captured at a flow rate of 8 L/min, while that of chloropyromorphite was found at 8.2 L/min. The detachment of hydrocerussite and plannerite could not be observed using the present experimental setup. The shear forces causing the detachments of cerussite and chloropyromorphite were determined to be 5.8 x 10-11 N and 3.1 x 10-10 N respectively using CFD. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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