Heat Melt Compaction as an Effective Tre

One of the technologies being tested at Ames Research Center as part of the logistics and repurposing project is heat melt compaction (HMC) of solid waste to reduce volume, remove water and render a biologically stable and safe product. This study focuses on the efficacy of the heat melt compaction process for killing microorganisms in waste, specifically assessing required time and temperature protocols to achieve sterilization. A controlled study examined the survival and potential re-growth of inoculated microorganisms over a 6-month storage period after heating and compaction. The ersatz solid waste was inoculated with Bacillus amyloliquefaciens and Rhodotorula mucilaginosa before the process. Microbiological analysis of compacted HMC tiles was conducted at various time points from 0 to 180 days in a controlled environment with embedded biological indicator strips to verify sterilization efficacy. Results indicated re-growth in all tile samples except one at a specific temperature and time—suggesting critical minimum conditions are necessary for complete sterilization. Additional observations included contamination from bacteria and fungi on compactor hardware, providing insight into cross-contamination risks. Further microbial analysis at lower temperatures will be discussed.