EARTH

[31013-24-03] A Comparative Study of Environmental Availability and Risks of Calcium Arsenate Sludge by Vitrification and Cement Solidification

Jingjing Ma¹, ○Yanjie Liang^1,2, Zongwen Zhao¹, Xiaobo Min^1,2 (1. Central South University, 2. Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution)

Chairman: Suwat Athichanagorn （Chulalongkorn University）, Dawan Wiwattanadate （Chulalongkorn University）

Keywords:Arsenic, Vitrification, Cement solidification, BCR, Environmental risk

The calcium arsenate sludge (CAS) was the product of arsenic waste water treatment with lime milk neutralization. The cement solidification is the most common treatment, but its enlargement ratio and stabilizational performance are not well. Nowadays, the vitrification treatment has attracted attention as an alternative method. However, environmental availability and risk of vitrification was uncertain. To obtain a more comprehensive understanding of modified iron phosphate glass system, borosilicate glass system and cement solidification, it is necessary to systematically quantify arsenic in solidified bodies (SBs), which is the objective of this paper. The total concentration, leaching characteristic and speciation of arsenic in both CAS and SBs were investigated to evaluate environmental risks of them. The environmental risks were described according to the RAC, GAI and RI, which showed that the solidification effect of vitrification was better than cement solidification, particularly, the modified iron phosphate glass martix posed a low risk to environment. In general, the modified iron phosphate glass system is a potentially effective treatment for protecting the environment.