Aluminum speciation in drinking water distribution system: A case study in northeastern China

Abstract

This study aimed to investigate the variation of aluminum species in a drinking water distribution system in a city in northeastern China. The aluminum species were determined by fluorometric methods. Results showed that suspended aluminum (Sus-Al) was the major species in the drinking water supplied by plant B and accounted for about 42% of the total aluminum (Tol-Al). The concentrations of Sus-Al and Tol-Al could be controlled effectively by in- troducing reservoir water. In the water source switching process, the water quality variation led to the suddenly release of Sus-Al, especially in a cast iron pipeline that had been in service for more than 30 years, but the soluble aluminum varied little. In the plant A service areas, the average concentrations of the inorganic monomeric aluminum (IM-Al), monomeric aluminum (Mon-Al), and soluble aluminum (Sol-Al) were 0.008 mg L −1 , 0.03 mg L −1 , and 0.04 mg L −1 , respectively, and their concentrations in the plant B service areas were higher. The pH and fluoride were the major parameters affecting the soluble aluminum speciation. With a solution pH of 6.5-7.5 and fluoride below 0.3 mg L −1 , the Sol-Al could be controlled within 0.1 mg L −1 . Water quality regulation and terminal filtration were suggested for residual aluminum control.