Abstract:
The purpose of this study was to compare the color removal and COD reduction in wastewater released from dye industry using four types of adsorption processes: 1st step by either soil or activated carbon; 2nd step (soil:activated carbon; 1:1) and 3rd step (soil:activated carbon; 2:1). Results showed that more than one step of adsorbent was able to treat wastewater containing dyes more efficiently than the use of one step process. Although there was no significantly different (p>0.05) in COD reduction between two and three steps, the two steps process could remove color intensity better than the three-steps process. Therefore, the two steps process was the most appropriate to remove color intensity and reduce COD (89.63%).Subsequencely, two sequencing steps for wastewater removal were conducted using adsorption and biological treatment. Fifteen centimeter hight of two-steps column was established. Removal of COD, suspended solid (SS), total dissolved solid (TDS) and sodium chloride concentration was 57.49%, 59.56%, 19.23% and 42.18%, respectively. The filtrated water from the first steps was transferred to activated sludges under aerobic, aerobic denitrifying, denitrifying and methanogenic conditions. Results showed that aerobic denitrifying condition was the most suitable of wastewater. Within 4 day, COD, SS and TDS of dyes-containing wastewater after hybrid treatment passed Thai Regulation of wastewater releasing in the environments, except sodium chloride concentration.