Efficiency of the Combined Chemical Precipitation -Reduction Process to Remove Dye and Chromium from Industry Wastewater of Home Appliance

Background: Industrial wastewater is one the most important pollutants of environment. This study aimed to evaluate the efficiency of the combined chemical precipitation-reduction process for removal of dye and chromium from wastewater of home appliance factories. Methods: This experimental study was performed in laboratory scale on wastewater from the dying unit of the home appliance factory. The process used was a combination of the chemical precipitation-reduction process. Combine sampling was done and ۲۱۴ samples were analyzed. COD, dye, and chromium were measured in samples. MgCl۲, Polyaluminium Chloride (PAC), and FeCl۳, cationic polymer and bentonite were used for chemical precipitation; and sodium meta bi sulfite was used for chemical reduction. Data were analysed by ANOVA and Tukey tests and by SPSS ۱۶ software. Results: The results show that PAC had the highest color removal efficiency (۹۰.۹۲%). Also, the highest COD removal was related to the combination of magnesium chloride (۱.۴ mg/l), poly aluminum chloride (۰.۶ mg/l), and the coagulant aid cationic polymer (۰.۴ mg/l) with an efficiency of ۸۹.۱۱%. Moreover, total efficiency of the combined chemical precipitation and reduction process in chromium removal was ۹۴%. Conclusion: The chemical precipitation- reduction process as a pre-treatment method has high efficiency in removal of COD, dye and chrome from wastewater of home appliance factories.

Keywords:

Industrial Wastewater Treatment , Chemical Coagulation , Chemical Reduction , Chromium , Dye