Treating in-tank dyeing wastewater using activated carbon

• Main Authors: LIAO,JIA-WEI, 廖嘉偉
• Other Authors: CHEN,SHYI-TIEN
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/a6e4d8

碩士 === 國立高雄第一科技大學 === 環境與安全衛生工程系碩士專班 === 105 === The general dyeing and finishing process includes: pre-treatment (desizing,scouring, bleaching, mercerizing), dyeing, printing and finishing processes. Over the operation, a variety of chemicals such as dyes, strong acid / alkali, redo-reagents etc. were present in the resulting wastewater. Other characteristics of the wastewater includes its high temperature, high COD, high color, and unstable pH value make the treatment of such wastewater a challenge. In Taiwan, dyeing and finishing industry accounted for a high proportion of industrial wastewater. In such stream, only about 10-20% of the wastewater discharged directly from the dyeing tank with high COD content, the rest is the cleaning water that has limited COD content. In reactive chemistry, the reaction rate is often proportional to the reactant’s concentration. Treatment of the highly concentrated dyeing wastewater can be more efficient and result in cost-savings. Thus, the objectives of this study included: (1) to investigate the efficiency of COD removal followed by the oxidative regeneration in treating the in-tank dyeing wastewater, (2) to confirm the possible factors of adsorption and regeneration and their most applicable operational conditions, and (3) to search the most feasible strategy and methods in treating in-tank dyeing wastewater by activated carbon. In-tank dyeing wastewater is provided by a dyeing company in southern Taiwan, the AC is a purchased, laboratory-grade product, and the oxidative reagents include peroxide and EDTA-Fe. The results of this study include: (1) In treating raw dyeing wastewater, light effect was minimal yet the use of the activated carbon (AC) appeared to adsorb 50-60% COD and the linear saturation q value was about 0.22 g-COD/g-AC, (2) The pH and temperature had little effect on dyeing wastewater adsorption using the AC, (3) If regeneration with water only, COD adsorption of the AC dropped ~10%; yet with as low as initial peroxide= 2.5% and EDTA-Fe= 2.12 mM as oxidative reagents, COD adsorption increased ~ 7%, (4) Use of 5-gram AC for five continuous adsorption and regeneration cycles, about 0.3625 grams of COD were removed in each run, which equaled to q= 0.3625/5= 0.0725 g-COD/g-AC, and (5) pH had little effect on AC regeneration; yet higher temperature resulted in higher AC adsorption after its regeneration. If regeneration temperature maintained at 60 oC, about 30% higher COD adsorption was observed than AC regenerated at 25 oC. Keywords: in-tank dyeing wastewater, catalytic oxidation, activated carbon adsorption, oxidative regeneration