Effects of Particle Size and Contact Time on the Reliability of Toxicity Characteristic Leaching Procedure for Solidified/Stabilized Waste

Abstract

Inconsistency in leaching results using the Toxicity Characteristic Leaching Procedure (TCLP) indicates that the procedure should contain specific guidance with respect to the following parameters: (1) minimum particle size, (2) contact time limit between leachant and waste. Experimental data show that there is approximately a 50% decrease in the amount of waste leached when a minimum particle size of 8 mm is applied. Results indicate that as the contact time between leachant and waste increases, the amount of waste leached increases drastically. The results suggest that restrictions should be set on these two parameters for TCLP results to be reliable and comparable for solidified/ stabilized waste.

Factors affecting TCLP lead leachability from computer CPUs

“…A decrease in particle size is generally thought to result in a greater fraction of leached chemical. Such a phenomenon has been reported for CRT glass and stabilized waste (Musson et al, 2000;Janusa et al, 1998). Iron concentrations (19 ± 9 vs. 52 ± 6) were significantly (a = 0.05) greater in the smaller particle size samples.…”

Implications for current regulatory waste toxicity characterisation methods from analysing metal and metalloid leaching from photovoltaic modules

“…For arsenic leaching, comparing landfill leachate to regulatory methods, the TCLP and the WET, shows much higher arsenic concentrations for the actual landfill leachate than for the regulatory methods, and equilibrium is not reached within the 18 h TCLP duration (Ghosh, Mukiibi, and Ela 2004). Increased lead concentrations for a solidified waste are found for increasing the leachate contact time, and decreased concentrations are found for applying a minimum particle size of 8 mm in addition to the maximum of 9.5 mm (Janusa et al 1998).…”

Leaching behavior of mineral processing waste: Comparison of batch and column investigations

“…However, other physicochemical factors such as pH, redox and microbial activity are also known to affect metal mobility from solids [9][10][11][12][13][14]. Most metals exhibited increased leaching at low and high pH levels [9,10,12,15].…”