Comparison of metals extractability from Al/Fe-based drinking water treatment residuals

• Published in: Environmental science and pollution research international Vol. 21; no. 23; pp. 13528 - 13538
• Main Authors: Wang, Changhui, Bai, Leilei, Pei, Yuansheng, Wendling, Laura A.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.12.2014; Springer Nature B.V
• Subjects: Aluminum; Aluminum Compounds - chemistry; Aquatic Pollution; arsenic; Atmospheric Protection/Air Quality Control/Air Pollution; barium; Bioavailability; By products; cadmium; calcium; China; chromium; cobalt; copper; Digestion; Drinking water; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental protection; Fractionation; Heavy metal content; in vitro digestion; In vitro testing; Investigations; Iron; Iron Compounds - chemistry; Laboratories; Leaching; lead; magnesium; Manganese; mercury; Metals; Metals - analysis; Metals - chemistry; molybdenum; nickel; Recycling; Research Article; Risk assessment; Sediments; selenium; sodium; Strontium; Studies; Toxicity; United States; United States Environmental Protection Agency; Waste management; Waste Water Technology; Water Management; Water Pollution Control; Water Purification; Water treatment; Water treatment plants; zinc; United States; China; China, People's Rep; Bioaccessibility; Risk; Fractionation; Metal; Drinking water treatment residue; TCLP
• ISSN: 0944-1344; 1614-7499; 1614-7499
• DOI: 10.1007/s11356-014-3300-2

Recycling of drinking water treatment residuals (WTRs) as environment amendments has attracted substantial interest due to their productive reuse concomitant with waste minimization. In the present study, the extractability of metals within six Al/Fe-hydroxide-comprised WTRs collected throughout China was investigated using fractionation, in vitro digestion and the toxicity characteristic leaching procedure (TCLP). The results suggested that the major components and structure of the WTRs investigated were similar. The WTRs were enriched in Al, Fe, Ca, and Mg, also contained varying quantities of As, Ba, Be, Cd, Co, Cr, Cu, K, Mn, Mo, Na, Ni, Pb, Sr, V, and Zn, but Ag, Hg, Sb, and Se were not detected. Most of the metals within the WTRs were largely non-extractable using the European Community Bureau of Reference (BCR) procedure, but many metals exhibited high bioaccessibility based on in vitro digestion. However, the WTRs could be classified as non-hazardous according to the TCLP assessment method used by the US Environmental Protection Agency (USEPA). Further analysis showed the communication factor, which is calculated as the ratio of total extractable metal by BCR procedure to the total metal, for most metals in the six WTRs, was similar, whereas the factor for Ba, Mn, Sr, and Zn varied substantially. Moreover, metals in the WTRs investigated had different risk assessment code. In summary, recycling of WTRs is subject to regulation based on assessment of risk due to metals prior to practical application.