การลดสีและสารอินทรีย์ในน้ำออกจากถังปฏิกรณ์ผลิตก๊าซชีวภาพของอุตสาหกรรมเอทานอลโดยใช้ถ่านกัมมันต์

Abstract

Biogas reactor effluent of ethanol industry contains dark brown color due to melanoidin and high concentration of organic compounds after anaerobic treatment. Acceptable color and organic substances measured as chemical oxygen demand (COD) for discharge cannot be achieved without some form of post-treatment. The objective of this study was to reduce color and organic compounds in biogas effluent by commercial activated carbon. The effects of concentration, GAC-CS dosage, contact time and pH value on color and organic compounds removals were determined. The experimental results showed GAC-CS had BET surface area of 1048.43 m2/g and total pore volume of 0.4505 cc/g. The color and COD reductions of 67.48% and 33.72%, respectively, were achieved at equilibrium using 20 g/L of GAC-CS with contact time 10 min, 25% dilution and pH of 2. However, the color and COD values of the treated wastewater are still higher than the standards. this research has been further studied for other commercial activated carbons. The results showed C-BON activated carbon has the highest efficiency in color and organic compounds removals as 99.46% and 93.00%, respectively, under the condition of biogas effluent concentration 25% v/v, pH value 2, 20 g/L C-BON activated carbon, and contact time 30 min. C-BON had BET surface area of 2034.56 m2/g and total pore volume of 1.822 cc/g. When C-BON activated carbon was recovered, the results showed 450ºC and contact time 30 min are the optimum temperature for activated carbon regeneration and can be reused up to 3 times. The GAC-CS and C-BON equilibrium adsorption is well described by Langmuir isotherm.