Solidification with water as a treatment method for air pollution control residues

Area of Science:

• Environmental Engineering
• Materials Science
• Waste Management

Background:

• Air pollution control (APC) residues from refuse-derived fuel (RDF) incineration require effective management.
• Solidification is a potential method for treating these hazardous waste materials.
• Understanding the mechanical properties and leaching behavior of solidified APC residues is crucial for safe disposal.

Purpose of the Study:

• To investigate the mechanical strength of solidified APC residues using water.
• To assess the leaching behavior of elements from the solidified material.
• To determine the influence of water addition, time, and temperature on mechanical strength and leaching.

Main Methods:

• Factorial design at two levels was employed to study the impact of water addition, time, and temperature on mechanical strength.
• The NEN 7345 diffusion-leaching test was used to evaluate element leaching.
• Analysis focused on the demobilization of specific elements by water solidification.

Main Results:

• Time, temperature, and the interaction of water addition with time significantly affected the mechanical strength of the solidified material (alpha=0.05).
• Leaching was found not to be diffusion-controlled, thus long-term leaching was not assessed.
• Water solidification considerably demobilized aluminum (Al), mercury (Hg), manganese (Mn), lead (Pb), silicon (Si), and zinc (Zn).

Conclusions:

• Water solidification is a viable method for improving the mechanical strength of APC residues.
• Certain elements (Al, Hg, Mn, Pb, Si, Zn) are effectively immobilized by this process.
• Further research into long-term leaching behavior under non-diffusion-controlled conditions may be warranted for other elements.