Long-term sampling of dioxin-like substances from a clinker kiln stack using alternative fuels

Area of Science:

• Environmental Science
• Chemical Engineering
• Pollution Control

Background:

• Cement production plants are potential sources of atmospheric pollutants.
• Upgrading clinker production lines can impact emission profiles.
• Assessing emissions is crucial for regulatory compliance and environmental protection.

Purpose of the Study:

• To characterize atmospheric emissions of PCDD/PCDF and dl-PCBs before and after upgrading a cement plant's clinker production line.
• To evaluate the impact of using alternative fuels (RDF, WWTP sludge) on these emissions.
• To compare emission levels with European Waste Incineration Directive limits.

Main Methods:

• Long-term sampling systems installed in the stack of both old and new clinker kilns.
• Emission evaluation over a two-year period for the old installation and subsequent evaluation for the new installation.
• Analysis of PCDD/PCDF and dl-PCB congener profiles and toxicity equivalency (TEQ).

Main Results:

• PCDD/PCDF emission values for both kilns were significantly below the EWID limit (100 pg I-TEQ/Nm³).
• dl-PCBs constituted approximately 25% of the total WHO-TEQ toxicity.
• The new installation demonstrated reduced PCDD/PCDF and dl-PCB emissions, especially when integrating alternative fuels.

Conclusions:

• The state-of-the-art cement plant installation effectively reduces PCDD/PCDF and dl-PCB emissions.
• Integration of alternative fuels (RDF, WWTP sludge) is compatible with low emission levels.
• Specific congeners like 2,3,7,8-TCDD, 2,3,4,7,8-PeCDF, and PCB-126 were identified as major contributors to TEQ.