Emission distribution of volatile organic compounds of semiconductor and photovoltaic (TFT-LCD) industries
For the emerging industrial technology industries, semiconductor and optoelectronics (TFT-LCD) industry, this study investigated the discharge of volatile organic compounds (VOCs) from industries in air, wastewater, and waste phases based on the mass balance theory. The whole plant emission factors for volatile organic compounds divided into two scenarios: a plant closed for the whole collection, including oven for a source. The findings of this study show that emissions are still unable to rule out the fugitive emissions may be, it should be consideration of the fugitive emissions in order to match the mass balance principle. For wafer fabrication and TFT-LCD manufacturing studied in this research, most of the organic substances produced during the process are discharged as waste (66.4 and 61.7%), followed by discharge through air pollution control facilities (about 8.41 and 9.9 %), wastewater discharge (about 5.33 and 5.48%), discharge through tailpipes (about 0.26 and 0.6 %), controllable emissions during the process (about 0.18 and 0.65 %), and the uncontrollable portion of emission (about 19.53 and 21.64 %). In order to reduce variability in emission estimation caused by errors in the detection, it is recommended that attention should be paid on the validness of sampling time. Sampling time should be adjusted according to each manufacturing process, and each sampling time should cover entire process. Furthermore, as a way of verifying its variability, multiple sets of samples should be taken at different time and averaged, with a view to minimize the effect of detection errors.