Discoloration and mineralization of a textile azo dye using a hybrid UV/O3/SBR process

Most synthetic dyes are toxic and hardly biodegradable compounds that enter the environment mainly through the discharged of non-treated textile industry effluents. The present study investigated the removal of the textile monoazo dye Reactive Red 198 (RR-198) from aqueous solutions using the ultraviolet light and ozonation alone and in combination (i.e., UV/O3) followed by a Sequencing Batch Reactor (SBR). The pH (5 � pH � 9) and dye initial concentration (50�300 mg/L) parameters were optimized in the ozonation process at reaction time of 0�60 min. Then, TOC removal and dye discoloration percentage was compared with the O3, UV and O3/UV processes. In order to compare the performance of the SBR in dye discoloration of RR-198 and TOC removal, four types of effluent, including Raw dye, O3-pretreated dye, UV-treated dye and UV/O3-pretreated dye were separately treated in the SBR system. In the ozonation process, by increasing the pH and reducing the initial dye concentration increased the discoloration percentage. The highest dye discoloration percentage and TOC removal obtained in the hybrid UV/O3/SBR process. Combining biological systems and Advanced Oxidation Processes is an appropriate option for the decomposition of resistant pollutants and increasing the biodegradability of these compounds and is applicable in the water and wastewater industry. © 2021, The Author(s)

Bioremediation for the Decolorization of Textile Dyes by Bacterial Strains Isolated from Dyeing Wastewater

Background: The major concern to meet environmental regulations is related with the decolorization and detoxification of industrial dyes contaminated wastewater. So, this study was undertaken to examine the use of bacteria isolated from wastewater of textile factories in the removal of the synthetic textile dyes (Sudan Black, Methyl Red, Malachite Green, Rhodamine B and Brilliant Cresyl Blue). Methods: Dye contaminated wastewater was collected from some synthetic textile factories in Gorgan and Gonbad, Iran, and evaluated for the screening and isolation of bacteria capable of decolorizing textile dyes. The effect of function of operational parameters includes temperature (25, 37 and 50 °C), pH (4, 6 and 8) and initial dye concentration (100, 200 and 300 mg/mL) on the efficiency and rate of discoloration was assessed. Results: Totally, out of the 19 bacterial isolates from textile wastewater: Five bacterial isolates showed dye discoloration ability and the most efficient bacterial isolates were Enterococcus faecium and Pantoea spp. that decolorized Methyl Red, Sudan Black and Malachite Green dyes at 25-37°C, concentration of 200-300 mg/mL and slightly acidic to neutral pH. Enterococcus bacterium was able to decolorize Sudan Black to the 19.79 in the concentration of 100 mg/ml and pH=8 and temperature of 50°C. The highest amount of decolorizing was observed by Pantoea on Malachite Green to the amount of 73. Enterococcus had the highest decolorizing on Methyl Red to the 65.7. The amount of decolorizing on Sudan Black by Enterococcus (49.9) was also higher than Pantoea (39.7). Conclusion: Isolated bacteria had a significant reduction in toxicity and cationic malachite green dye and azo dye- methyl red. Thus, bacteria can be used in full-scale industrial wastewater treatment with the bio-synergy and its application in discoloration. © 2022. Jordan Journal of Biological Sciences. All Rights Reserved

Synthesis and characterization of nanoparticles and composites as bactericides

In the present study, SiO2-TiO2 hybrid nanomaterial and zeolite-TiO2 (Z-TiO2) composites were synthesized by the sol-gel method. Then, the antibacterial activity of the above-mentioned synthesized materials, SiO2 and zeolite (Z) was investigated by the disk diffusion method using Echerichia coli and Enterobacter aerogenes as test microorganisms. All the materials showed antibacterial activity against E. coli with 7.2, 10.7, 3.5 and 8.2 mm of inhibition zone for SiO2-TiO2 hybrid nanomaterial, SiO2, zeolite and Z-TiO2 composite, respectively. However, none of them showed antibacterial activity against E. aerogenes. The obtained results pointed out that these natural-based materials (i.e. Z, SiO2, Z-TiO2 and SiO2-TiO2), known to be noncarcinogenic and nontoxic, can be used as disinfectants against E. coli (an important indicator of the bacteriological quality of water) as safe and eco-friendly alternatives to chlorine. © 2019 Elsevier B.V

Rapid and high purification of olive mill wastewater (OMV) with the combination electrocoagulation-catalytic sonoproxone processes

Background and purpose: Olive Mill Wastewater (OMW) is one of the most problematic wastewater in the food industry. Thus, its ineffective treatment causes severe pollution in the environment. In this study, the treatment of OMW by combining electrocoagulation (EC) and catalytic sonoperoxone processes was investigated. Materials and methods: The efficiency of turbidity removal and mineralization of OMW using EC was investigated by applying the following operation variables: type of electrode (iron and aluminum), reaction time (0- 60 min) and current density (0.08�0.77 A/dm 2 ). Then, a single ozonation process (SOP), a catalytic ozonation process (COP), an ultrasonic process (US), H 2 O 2 , COP/US, a peroxone process (H 2 O 2 /O 3 ) and a catalytic sonoperoxone process (H 2 O 2 /COP/US) were performed. Finally, the biodegradability of OMW was measured by using BOD 5 /TOC index. Results: Maximum removal efficiency of the turbidity, Total Organic Carbon (TOC) and consumed electrode in the EC were 82, 75 and 634 mg of iron electrode/L of OMWW, respectively. The TOC removal efficiency of the pretreated OMW by using the following oxidation processes of US, H 2 O 2 , SOP, O 3 /H 2 O 2 , COP, COP/US and H 2 O 2 /COP/US was 8, 15, 20, 25, 61, 68 and 75, respectively. In addition, the biodegradability index (BOD 5 /TOC) in the catalytic sonoperoxone process increased by as much as 32 compared to raw OMWW. Conclusion: The EC process caused an effective per-treatment of OMW and combined by sonoperoxone process improved its biological biodegradability. So, this process can be used for the efficient treatment of OMWW and the wastewater produced by similar industries. © 2019 Taiwan Institute of Chemical Engineer