en تخصصي Special Original articles <p dir="ltr" style="text-align: justify;"><strong><em><span style="letter-spacing:.1pt;"><span style="color:black;"><span style="font-family:times new roman,serif;"><span style="font-size:10.0pt;">Introduction</span></span></span></span></em></strong><strong><span style="letter-spacing:.1pt;"><span style="color:black;"><span style="font-family:times new roman,serif;"><span style="font-size:10.0pt;">:</span></span></span></span></strong><span style="letter-spacing:.1pt;"><span style="color:black;"><span style="font-family:times new roman,serif;"><span style="font-size:10.0pt;"> The Powdered Activated Carbon Treatment (PACT) has been proposed as an alternative in wastewater treatment and wastewater biomass protection against toxic substances. This study aims to evaluate PACT performance in treating dyes, acid orange, and remazol brilliant reactive blue.</span></span></span></span><br> <strong><em><span style="letter-spacing:.1pt;"><span style="color:black;"><span style="font-family:times new roman,serif;"><span style="font-size:10.0pt;">Materials and Methods</span></span></span></span></em></strong><strong><span style="letter-spacing:.1pt;"><span style="color:black;"><span style="font-family:times new roman,serif;"><span style="font-size:10.0pt;">:</span></span></span></span></strong><span style="letter-spacing:.1pt;"><span style="color:black;"><span style="font-family:times new roman,serif;"><span style="font-size:10.0pt;"> This empirical- applied research was carried out in pilot scale in which different dye </span></span></span></span><span style="letter-spacing:.1pt;"><span style="font-family:times new roman,serif;"><span style="font-size:10.0pt;">removal systems were tested<span style="color:black;">: activated sludge, PAC, and the combined activated carbon&ndash;biomass system. The degradability of selected dyes was evaluated through Zahn-Wellens method. Also, tests continued by adding different concentrations of powdered activated carbon and it^&rsquo;s effect on activated sludge in different operating conditions was investigated. American Dye Manufacture Institute (ADMI) method was utilized for determination of dye removal in samples.</span></span></span></span><br> <strong><em><span style="letter-spacing:.1pt;"><span style="color:black;"><span style="font-family:times new roman,serif;"><span style="font-size:10.0pt;">Results</span></span></span></span></em></strong><strong><span style="letter-spacing:.1pt;"><span style="color:black;"><span style="font-family:times new roman,serif;"><span style="font-size:10.0pt;">:</span></span></span></span></strong><span style="letter-spacing:.1pt;"><span style="color:black;"><span style="font-family:times new roman,serif;"><span style="font-size:10.0pt;"> Results revealed that dye removal in combined carbon&ndash;biomass system was faster and more efficient than activated sludge individually. So, in the wastewater with the dye concentration of 100 ppm, the dye removals through biological process alone were equal to 60 % and 12.5 % for acidic and reactive dyes, respectively. The best PAC efficiency in activated sludge process was obtained in 1500 mg/L PAC concentration. Hydraulic Retention Time (HRT) and the optimum temperature of dyes&#39; removal were determined 28 hours and 30 &deg;C, orderly; in these conditions the dye removal efficiency of 98.18 % was obtained. Also the dye removal using activated carbon&ndash;biomass system was adequately described by combining the kinetic equations. </span></span></span></span><br> <strong><em><span style="letter-spacing:.1pt;"><span style="color:black;"><span style="font-family:times new roman,serif;"><span style="font-size:10.0pt;">Conclusion</span></span></span></span></em></strong><strong><span style="letter-spacing:.1pt;"><span style="color:black;"><span style="font-family:times new roman,serif;"><span style="font-size:10.0pt;">:</span></span></span></span></strong><span style="letter-spacing:.1pt;"><span style="color:black;"><span style="font-family:times new roman,serif;"><span style="font-size:10.0pt;"> PACT could be considered as an acceptable and highly efficient method for removal of different dyes in textile industry.</span></span></span></span><br> &nbsp;</p> Dye,Biological,Treatment, Adsorption. 141 152 http://jehsd.ssu.ac.ir/browse.php?a_code=A-10-1-18&slc_lang=en&sid=1 Abdolmajid Gholizadeh No Environmental Science and Technology Research Center, Department of Environmental Health Engineering, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran. Mitra Gholami No Department of Environmental Health, School of Public Health, Iran University of Medical Sciences, Tehran, Iran. Ali Asghar Ebrahimi No Environmental Science and Technology Research Center, Department of Environmental Health Engineering, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran. Mohammad Miri m_miri87@yahoo.com Yes Environmental Science and Technology Research Center, Department of Environmental Health Engineering, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran. Ali Nikoonahad No Environmental Science and Technology Research Center, Department of Environmental Health Engineering, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.