Characterization and release profile of (Mn, Al)-bearing deposits in drinking water distribution systems. (April 2018)

• Record Type: Journal Article
• Authors: Li, Guiwei; Ding, Yuanxun; Xu, Hongfu; Jin, Junwei; Shi, Baoyou
• Is Part Of: Chemosphere. Volume 197(2018)
• Page Start: 73
• Page End: 80
• Publication Date: 2018-04
• Subjects: Drinking water distribution system -- Pipe deposits -- Manganese -- Aluminum -- Release; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2018.01.027
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Inorganic contaminants accumulation in drinking water distribution systems (DWDS) is a great threat to water quality and safety. This work assessed the main risk factors for different water pipes and discovered the release profile of accumulated materials in a full scale distribution system frequently suffered from water discoloration problem. Physicochemical characterization of pipe deposits were performed using X-ray fluorescence, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The metal release profile was obtained through continuous monitoring of a full-scale DWDS area. The results showed that aluminum and manganese were the main metals of deposits in nonmetallic pipes, while iron was dominant in iron-based pipe corrosion scales. Manganese primarily existed as MnO2 without well crystalline form. The relative abundance of Mn and Fe in deposits changed with their distance from the water treatment plant. Compared with iron in corrosion scales, Mn and Al were more labile to be released back into bulk water during unidirectional flushing process. A main finding of this work is the co-release behavior of Mn and Al in particulate form and significant correlation exists between these two metals. Dual control of manganese and aluminum in treated water is proposed to be essential to cope with discoloration and trace metal contamination in DWDS. Graphical abstract: Image 1 Highlights: Al and Mn were most abundant in deposits accumulated in nonmetallic pipes. The proportion of Mn and Fe in deposits varied along with the pipeline. Accumulated Mn and Al were labile to be released under hydraulic disturbance. Co-release of Mn and Al was observed during flushing and field monitoring. A comprehensive strategy is required for deposits control in distribution systems.