Siloxanes in Biogas: Formation and Effect on Biogas Quality and Energy Costs

Project description 

Siloxanes are a family of emerging compounds in municipal solid waste (MSW) due to their increasing use in consumer products (i.e., fabrics, paper, concrete, wood, adhesive surfaces). The use of siloxane based coatings and additives have increased significantly in the recent years due to their excellent water repelling (antimicrobial-antifouling) characteristics (e.g., makeup, shampoo, and surface coatings for wood and concrete surfaces, fabric coatings). Initial concerns for siloxanes in solid waste have been due to excessive deposit formation in gas engines at waste to energy (WTE) facilities operated with landfill gas (LFG).

Flow chart

Release mechanisms of siloxanes in waste streams into the environment.

The presence of siloxanes in LFG reduces the efficiency of energy recovery from biogas due to the formation of deposit and significantly higher oxygen demand of siloxanes than methane. WTE plant operators are facing a choice between installing biogas purification equipment or controlling the problem with increased maintenance activities

Objectives of this research are to evaluate:

  1. Compare levels and types of siloxanes present in biogas produced at landfills and anaerobic digesters;
  2. Evaluate conditions which cause differences in siloxane profiles between landfills and anaerobic digesters;
  3. Evaluate potential effects of siloxanes on the operation of biogas to energy facilities;
  4. Evaluate potential effects of siloxanes on energy costs due to increased maintenance activities and/or installation of pretreatment units.

deposit samplessiloxanes in biogas

This project will expand the activities initiated during the previous project sponsored by the Hinkley Center funded in 2012 (Hinkley Center Report No. 14-1232036, Siloxanes in MSW: Quantities in Waste Components, Release Mechanisms during Waste Decomposition and Fate in the Environment).



State University System of Florida
Hinkley Center for Solid and Hazardous Waste Management