Modelling of PCDD/F release from MSW bio-drying.

Area of Science:

• Environmental Science
• Waste Management
• Chemical Engineering

Background:

• Municipal solid waste (MSW) bio-drying is a biological mechanical treatment (BMT) for dewatering waste using exothermic reactions.
• Bio-drying enhances refuse-derived fuel (RDF) generation by reducing waste weight and facilitating the removal of non-combustible materials.
• Limited data exists on polychlorinated dibenzodioxins and dibenzofurans (PCDD/F) emissions from BMT processes.

Purpose of the Study:

• To investigate the behavior and emission of PCDD/F during MSW bio-drying.
• To propose a theory explaining PCDD/F enrichment in air exiting biological treatment processes.
• To account for the influence of initial PCDD/F concentration in ambient air.

Main Methods:

• Experimentation was conducted to study PCDD/F behavior during MSW bio-drying.
• An original theory was developed to explain PCDD/F enrichment in exhaust air.
• The role of initial PCDD/F concentration and volatile solids consumption was analyzed.

Main Results:

• PCDD/F may be released from volatile solids consumed during the bio-drying process.
• The concentration of PCDD/F in the waste and the extent of volatile solids consumption influence emission factors.
• Experimental results support the theory of PCDD/F release linked to volatile solids breakdown.

Conclusions:

• The bio-drying of MSW can lead to the release of PCDD/F into the air.
• Volatile solids consumption during bio-drying is a key factor in PCDD/F emissions.
• Variations in bio-drying processes explain differing PCDD/F emission factors reported in literature.