A safe and efficient technology of recovering nano glass from penicillin bottles of medical wastes

Waste penicillin bottles, a main component of medical wastes, have greatly produced in the world. Because of containing residual medicines and different microorganism, this kind of medical wastes is considered as hazardous waste. The unidentified microorganism inside waste penicillin bottles makes it difficult to dispose and manage. To our knowledge, there was little published information about the suitable recovery technology of waste penicillin bottles. In this study, the microorganisms in penicillin bottles were identified by the methods of gram staining and gene sequencing. Two gram-positive bacteria in the penicillin bottles were found, one was gram-negative bacterium, the other was fungus. The results of the analysis of gene sequencing and phylogenetic trees of the four bacterial showed three injurious microorganisms (Cladosporium australiense, Staphylococcus haemolyticu, and Vagococcus carniphilus)were presented in waste penicillin bottles. We also developed a novel process to recover nano glass from waste penicillin bottles. It included the processes of shearing, screen, and ball-milling. When the ball-milling time was greater than 36 h, most of the glass particles had the size ranged in 200–400 nm, 400–600 nm, and 600–800 nm, even reached the size of 0–200 nm. Ball-milling of the glass of waste penicillin bottles will bring a certain economic benefits by selling this nano glass. Additionally, we also found the transient temperature on glass particles during ball-milling process could reach 476 °C, which was enough to kill the injurious microorganisms. Therefore, ball-milling can reduce the cost of sterilization of medical wastes. This study provided a new and safe technology of recovering nano glass from penicillin bottles of medical wastes.