Type of Document	Master's Thesis
Author	Kvech, Steven Joseph
URN	etd-06292001-090818
Title	Formation of Aluminum Containing Solids in Drinking Water: Influence on Pb/Cu Corrosion, Al Solubility and Enhanced Softening
Degree	Master of Science
Department	Environmental Engineering
Advisory Committee	Advisor Name Title Edwards, Marc A. Committee Chair Dietrich, Andrea M. Committee Member Knocke, William R. Committee Member
Keywords	coagulation magnesium lead corrosion softening silica copper corrosion aluminum
Date of Defense	2001-05-10
Availability	unrestricted
Abstract Aluminum salts are used as the primary coagulants in the majority of United States drinking water treatment plants. Despite decades of practical experience, there are important knowledge gaps regarding the effects of residual Al on distribution system materials as well as specific types of solids formed. The first phase of this work examined the formation of aluminosilicate deposits in copper and lead pipes using water from Denver, Colorado. It was anticipated was that these deposits could form barrier films on the pipe, protecting it from corrosion. However, the deposits had slightly detrimental effects on leaching of metal to water, and higher levels of aluminosilicates could further worsen corrosion by-product release. The second phase of work attempted to extend understanding of aluminum solubility controls by accounting for effects of sulfate and formation of solids other than Al(OH)3 during water treatment. Sulfate was found to destabilize small Al(OH)3 colloids resulting in agglomeration into larger flocs from pH 5.0-6.2 . At pH 9.0 and above, Al-Mg, Al-Mg-Si and Al-Si solids were discovered to control Al solubility, while also having significant impacts on the precipitation of calcite in the presence of silica and overall softening effectiveness. This could be of considerable importance to water treatment practice. These solids also had some potential for removal of arsenic, TOC and boron.
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