Treatment of Industrial Wastewater of Variable Quality Using Ultrasound Irradiation

This paper investigated the use of ultrasound irradiation to treat real mixed industrial wastewater under various conditions, including single and dual frequencies, variable wastewater strengths, and different operating conditions, including flow rates/residence times. This work is important to evaluate the organics’ removal efficiency and to identify operational control bottlenecks under actual wastewater conditions. The highest removal efficiencies were ۶۹.۵% and ۳۱.۹% for COD and TOC, respectively, for the high-strength wastewater, which were found to occur at ۱۶ kHz frequencies and ۵۰۰ ml/min flow rate. The removal efficiencies were slightly less in the case of medium-strength wastewater (۶۶.۷ and ۲۵.۳% for COD and TOC, respectively). They were found to occur at dual frequencies of ۱۶/۲۰ kHz and ۱۵۰۰ and ۱۰۰۰ ml/min, respectively. For the low-strength wastewater, the efficiencies reached ۷۸.۶ and ۹.۱% for COD and TOC, respectively, at the same frequency and flow rates as the medium-strength wastewater. These findings demonstrated the effectiveness of dual frequency in medium- to low-strength wastewater. Among the organics monitored, chloroform (CHCl۳), tetrachloroethene (C۲Cl۴), ۱,۴ dichlorobenzene (C۶H۴Cl۲), and dichloromethane (CH۲Cl۲) exhibited variable removal, and in some cases, the removal was found to be negative, indicating intermediary products as a result of incomplete oxidation of organics. Besides the frequency and flow rate, it was found that the concentration of metals and organics are mostly positive influencers on organics removal. At the same time, TDS and pH have mixed effects, but they positively influence organics' removal at higher flows in a few instances. Additionally, as the residence time decreased, the concentration of organics and the pH negatively influenced organics removal. Doi: ۱۰.۲۸۹۹۱/CEJ-۲۰۲۵-۰۱۱-۰۴-۰۱۳ Full Text: PDF

Keywords:

Advanced Oxidation Processes , Cavitation , Dual Frequency , Organic Degradation , Ultrasound Technology , Wastewater Treatment.