Reuse of Industrial Wastewater Semiconductor Industry

Abstract

Semiconductor manufacturing processes generate large volumes of wastewater that of ten contain hazardous substances and fine particulate matter. The reuse of this industrial wastewater through membrane filtration technologies has become an important focus due to the growing demand for sustainable treatment solutions. This study presents novel findings on industrial wastewater treatment and reuse using two different experi mental setups. In the first phase of the study, industrial wastewater samples were taken and analyzed from four different wastewater streams. Key parameters were tested from the permeate and retentate to identify composition in water quality to provide a foundation for selecting the most suitable treatment technologies. The results highlighted a complex composition and high concentrations of pollutants, such as dissolved ions from inorganic compounds, total solids and fluoride. Based on wastewater characterization and literature review, two separate treatment trains were chosen and tested in laboratory to assess industrial wastewater reclamation. Experimental Setup 1 consisted of coagulation and flocculation, ceramic membranes (UF), and polymeric membranes (RO). Experimental Setup 2 consisted of coagulation and flocculation, ceramic membranes (UF), polymeric membranes (NF) and Direct Con tact Membrane Distillation (DCMD). The performance of these were analyzed based on results from water quality, permeate flux, and water recovery ratios. In both Setups, during the coagulation and flocculation phase of the treatment, total sol ids are aggregated into larger particles decreasing both TS and turbidity values signifi cantly. However, the removal was not as efficient during the coagulation phase in Exper imental Setup 1 as in Setup 2, except for COD. In Experimental Setup 1, the treatment from UF to RO shows more rapid reductions in conductivity, total solids (TS), and NH3- N. This suggests that the processes during and after UF are highly effective in removing both suspended particles and dissolved ions. In contrast, Experimental Setup 2 shows slower, more gradual improvements after UF. The changes in conductivity, TS, turbidity, ammonia, COD, and TOC from UF to NF and from NF to DCMD are steadily decreasing. Both setups showed similar overall recovery rates between 54 % and 56 % (RO 2nd pass and DCMD respectively). However, Setup 1 had much lower water flux than Setup 2 for UF (39.3 L/m2h and 99.2 L/m2h respectively). This difference likely results from variation in membrane pore size, though material differences may also have contributed. While both treatment trains were effective, Setup 1 with ultrafiltration (UF) and reverse osmosis (RO) could offer a more accessible option for wastewater treatment and reuse, since the technologies have been studied already with good results in semiconductor industry. Nevertheless, Setup 2 with DCMD also showed very good results for the water quality. It is now being developed for full-scale use, which could make it a viable option.