Beneficial Byproducts vs. Bottom Ash and Flyash
In a Alter NRG Plasma Gasifier, particulate is removed from the syngas downstream from the gasifier. However, the particulate can be recycled back into the gasifier for destruction (and also for further energy recovery) and therefore does not become a byproduct that requires disposal.
Instead of slag, incineration plants produce bottom ash and flyash. The flyash requires special disposal and in many jurisdictions is considered hazardous waste.
Assuming that particulate is recycled back into the gasifier, less than 2% of the material introduced needs to be sent to landfill. In comparison, about 20% to 30% of the waste processed in an incinerator must be sent to landfill.