Abstract

Cardboard recycling industrials are one of the major wastewater-producing industries. Bioremediation processes are economical and eco-friendly alternatives for industrial wastewater treatment. This study aimed to evaluate the bioremediation of cardboard recycling industrial wastewater by isolated native fungal strains. At first, samples of the cardboard recycling industry wastewater were cultured on Sabouraud dextrose agar. After that, the grown colonies were identified using morphological characteristics and microscopic observation. In this study, fungi including Aspergillus niger, Aspergillus flavus, Penicillium digitatum, Fusarium, Alternaria, Paecillomyces, Drechslera, Geotrichum, Mucor, and Absidia in cardboard recycling industrial wastewater were identified. Considering the frequency of grown fungi, A. niger, A. flavus, and P. digitatum were selected for bioremediation of the cardboard recycling industry wastewater. Then a suspension containing 1 x 10(6) CFU mL(-1) of fungal spore and the wastewater in dilutions of 25, 50, and 90 and pH levels of 5, 7, and 8 were prepared. Following that, 10 mL of fungal spore suspension was inoculated into the samples for decolorization and chemical oxygen demand (COD) removal and incubated for 10 d. The results of this study were analyzed by SPSS software and one-way ANOVA tests were performed and the significance level was considered p < 0.05. In this study, the maximum decolorization was obtained by A. flavus (50.58) at pH of 7 and dilution 25 and the maximum removal efficiency of COD was obtained by P. digitatum (70.98) at pH of 5 and dilution 25 for 10 d. This study confirms that native fungi have the potential to decolorize and remove COD from the cardboard recycling industry wastewater.