Combined physical, chemical and biological treatments of wastewater containing organics from a semiconductor plant

• Published in: Journal of hazardous materials 2003-02, Vol.97 (1), p.159-171
• Main Authors: Lin, Sheng H., Kiang, Chang D.
• Format: Article
• Language: English
• Subjects: Activated sludge; Air; Air stripping; Applied sciences; Biodegradation, Environmental; Biological and medical sciences; Biological treatment of waters; Bioreactors; Biotechnology; Chemical coagulation; Conservation of Natural Resources; Environment and pollution; Exact sciences and technology; Fenton oxidation; Fundamental and applied biological sciences. Psychology; Hydrogen Peroxide; Industrial applications and implications. Economical aspects; Industrial Waste; Industrial wastewaters; Iron; Oxidants; Oxidation-Reduction; Oxygen; Pollution; Semiconductor wastewater; Semiconductors; Sequencing batch reactor; Waste Disposal, Fluid - methods; Wastewaters; Water Pollutants - isolation & purification; Water treatment and pollution
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/S0304-3894(02)00257-1

Wastewater containing organics from a semiconductor plant was experimentally investigated in this study. The wastewater is characterized by strong color, high chemical oxygen demand (COD), a large amount of refractory volatile organic compounds and low biodegradability. Because of these characteristics, treatment of this wastewater by traditional activated sludge method is essentially impossible. In the present work, combined physical, chemical and biological methods were synergistically utilized to tackle the wastewater. The combined treatment consisted of air stripping, modified Fenton oxidation and sequencing batch reactor (SBR) method. Air stripping was employed to remove the majority of volatile organic components (notably isopropyl alcohol) from the wastewater, while the Fenton treatment decomposed the remaining refractory organics leading to simultaneous reductions of wastewater COD and color. After proper dilution with other low-strength, organics-containing wastewater stream, the wastewater effluent was finally treated by the SBR method. Experimental tests were conducted to determine the effectiveness and the optimum operating conditions of each treatment process. Test results clearly demonstrated the advantages of the combined treatments. The treatment train was found capable of lowering the wastewater COD concentration from as high as 80,000 mg/l to below 100 mg/l and completely eliminating the wastewater color. The overall water quality of the final effluent exceeded the direct discharge standard and the effluent can even be considered for reuse.