Environmental Controls
When the Reverse Polymerization of the medical waste is complete, the sterilized carbon residue is cooled then ground to compact the mass and blunt the sharps. The Reverse Polymerization process produces sterilized carbon residue suitable for municipal landfill disposal. The volume of sterilized residue is approximately 20% of the original waste. One hundred pounds of waste is reduced to unrecognizable landfill-ready sterilized carbon residue weighing approximately 20 pounds.
The flow of off-gases leaving the chamber is very low, peaking at 60 cfm and averaging, 40 cfm. This flow volume is less than that of a typical bathroom exhaust fan. Comparing the flow from an MD-1000, incinerators exhaust orders of magnitude more gases.
MD-1000 off-gases can be acidic and are passed through a simple and proven commercially available scrubber to raise the pH. The low pH is mainly caused by the release of chlorine from the breakdown of PVC plastic. There has been a significant reduction in the use of PVC as disposable packaging in many countries.
After the scrubber, off-gases may contain low concentrations of low molecular weight hydrocarbons resulting from the break-down of plastics in the waste. Off-gas control is achieved through efficient process design incorporating either a microturbine or a thermal oxidizer. The preferred solution is a microturbine since the off gases can be used as makeup air or mixed with natural gases powering the microturbine to generate electricity. Makeup air is added if a thermal oxidizer is used, resulting in a low flow exhaust of clean gases to the atmosphere.
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