Stabilizing arsenic-laden residuals from ion exchange processes

ENVR 43

Thomas R. Steinwinder, steinth@auburn.edu1, Dongye Zhao, dzhao@eng.auburn.edu1, Mark O. Barnett2, and Byungryul An, anbyung@auburn.edu1. (1) Environmental Engineering Program, Department of Civil Engineering, Auburn University, 238 Harbert Engineering Center, Auburn, AL 36849, (2) Department of Civil Engineering, Auburn University, 238 Harbert Engineering Center, Auburn University, Auburn, AL 36830
The goal of this research was to develop an engineered treatment process that will maximize the stability of ion exchange process waste residuals. Simulated regenerant brine was treated with FeCl3 under varied pH, Fe addition, wet and dry aging time and temperature. The effects of these factors were observed for both As removal from the spent brine and for stability of the resulting residuals as determined by the TCLP and California WET leaching tests. Nearly 100% As removal was achieved at an Fe/As molar ratio as low as 2 in the pH range of 3~7. Increasing the Fe/As from 5 to 15 resulted in >95% decrease in the amount of As leached. Increasing the treatment pH from 3.6 to 12 decreased As leachability by >90%. Furthermore, increasing the treatment temperature from 5° to 50°C lowered the total As leached from 44% to ~5%.
 

Occurrence, Chemistry, Toxicity and Remediation of Arsenic
8:00 AM-11:20 AM, Monday, 27 March 2006 Georgia World Congress Center -- B218, Oral

Division of Environmental Chemistry

The 231st ACS National Meeting, Atlanta, GA, March 26-30, 2006