Evaluation of Powdered-Activated Carbon Treatment (PACT) Process in Textile Dye Removal

Background and Objective: PACT is an adsorption- degradation process through which slowly or non-biodegradable waste water compounds such as dye can be degraded. This study was carried out to evaluate the efficacy of PACT in removal of dyes form textile industry wastewaters. Materials and Methods: This research was carried out in pilot scale. The pilot design had two parts: an aeration tank with ۴۰L volume and a clarifier with ۱۲L volume. The dyes used in this research were acid and reactive dyes in different concentrations which are mostly used in textile industries. First, the biodegradability of the dye was studied through Zahen-Wellens method (ISO ۹۸۸۸, ۱۹۹۹). Then, dye removal efficiency in different conditions of powdered-activated carbon concentration and operational conditions were evaluated. American Dye Manufacture Institute (ADMI) method was utilized for determination of dye removal in samples. Results: Biodegradability of acid dyes and basic dyes in ۱۰۰ mg/L dye concentration, were ۶۰ and ۸۰% respectively. On the other hand, the best efficiency for application of PAC in activated sludge process, was obtained in ۱۵۰۰ mg/L PAC concentration. In this situation, with ۳۰ hydraulic retention time, and ۳۰oC temperature, the rejection percent of dye was ۹۸.۸%.  Conclusion: PACT process could be the best method for removal of different dyes  used in textile industry with high efficiency (up to ۹۰%). Application of this method in treatment of textile wastewaters is an important economic improvement, which in a single step, allows the removal of COD and color from textile wastewater without additional physicochemical treatment.

Keywords:

Textile wastewater , Active sludge , Powdered-activated carbon treatment , Dye