Treatment of Plastic Waste by Melt Densification- Operational Experience at CWMF

A melt densification unit (MDU) was set up at CWMF with a facility for melting 20 kg of the plastic waste in each batch in a 200L MS drum. The system has a furnace with vacuum chamber where plastic waste in drum is melted and an off gas treatment system consisting of a scrubber followed by HEPA filter. A continuous stack monitor is installed to estimate any release of radioactivity in the off-gases. This paper describes the operational experience of melting of different plastic wastes namely polythene sheets & bottles, HDPE pipes and cans, PVC shoe covers and neoprene gloves. About 47M3 of β-γ and 18 M3 of α contaminated plastic wastes were melted using the above MDU. The volume reduction factors varied from 2.5 to 30 depending on the initial bulk density of the material. The radioactivity in the off-gases was found to be always below detectable limits. The leach indices of waste matrices were 2 to 3 orders better than the stipulated limits.