8. The U.S. EPA requires hazardous waste incinerators to meet a standard of 99.99 percent destruction and removal of organic hazardous constituents injected into the incinerator.This efficiency is referred to as "four nines ORE." For especially toxic waste the DRE must be "six nines." The efficiency is to be calculated by measuring the mass flow rate of organic constituent entering the incinerator and the mass flow rate of constituent exiting the incinerator stack. A schematic of the process is shown in Figure 1. One of the difficulties of assuring these levels of destruction is the ability to measure the contaminant in the exhaust gas. Draw a mass balance diagram for the process and determine the allowable quantity of contaminant in the exit stream if the incinerator is burning 1,0000 g/s of hazardous constituent. (Note: the number of significant figures is very important in this calculation.) If the incinerator is 90 percent efficient in destroying the hazardous constituent, what scrubber efficiency is required to meet the standard?

Fig: 1

Fig: 2