This master thesis analysis the impact of increased recirculated process water of GLOBALFOUNDIRES (GF) on the reduction of the total organic carbon (TOC) and urea concentration. Therefore, quantitative studies have been carried out to evaluate if an increased recirculated process water is beneficial in removing these two substances.
TOC concentrations were determined through a measurement campaign composed of three measuring sets 1, 2 and 3 with different recirculation rates. Considering the differ-ent measuring dates, representative recirculation rates of 85, 104 and 141 m3/h for set 1, 2 and 3 were selected. However, the urea determination was carried out only in a similar experiment.
A greater reduction of TOC (13 %), compared to the measuring set 1 (TOC removal of 9 %), could be reported in the second measuring set despite a shorter residence time in the Ultraviolet Lamps (UVLP). Therefore, compared to an extended residence time, an increased recirculation of process water seems favorable for the reduction of easily degradable organic substances. During the measuring set 2 and 3, similar TOC removal rate of 13 % and 12 % respectively could be reported. Therefore, an increased resi-dence time seems to have a beneficial effect on the removal of scarcely degradable organic substances. No significant increase in the TOC removal rate was found at a maximum recirculation rate. The greatest TOC removal could be identified at a recircu-lation rate of 104 m3/h. Furthermore, an urea removal of 12.5 % could be reported un-der same conditions as in measuring set 3 in a separate experiment, due to the UVLP. This is a surprising found as UVLP are not targeted to remove urea from ultrapure wa-ters. Based on the obtained results, it can be recommended to increase the recirculated process water as temporary measure to reduce TOC and urea concentrations in the ultrapure water treatment. This master thesis targets water management students as well as engineers of ultrapure water treatment for GF.