Emmanuel ADAH Thesis defense

As the use of engineered nanomaterials (ENM) in industrial and consumer products increases, a larger amount of ENM will likely end up in waste streams at the end of their life and potentially be released into the environment. Globally, it is estimated that more than 300,000 metric tons of ENM are released into landfills, soil, water, and air each year. Recent research has shown that engineered nanomaterials can survive the combustion process in waste incineration and end up in flue gas. However, little is known about the capture efficiency of ENMs within incineration flue gas cleaning technologies. Wet scrubbers, which are primarily designed to treat acidic pollutants, can also help reduce particulate matter (PM) emissions. However, no studies have been conducted to evaluate the effectiveness of a spray scrubber in collecting nanoparticles under waste incineration conditions. The present thesis aims to evaluate the performance of a pilot-scale scrubber concerning nanoparticle collection contained in an incineration flue gas representing the conditions of a hazardous waste incineration plant spray scrubber in terms of height-to-diameter ratio, liquid-to-gas ratio, gas inlet/outlet temperatures, gas humidity, gas residence time, and gas flow regime, droplet diameter and particle concentrations. Also, the influence of three independent operating factors - gas flowrate, liquid flowrate, and droplet diameter on the collection of carbon nanoparticles by a pilot-scale scrubber was investigated using the Design of Experiment - Box-Behnken design methodology