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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. [ABSTRACT FROM AUTHOR]

Highlights • In the recent paper OMWW purification has been investigated using combined electrocoagulation and advanced oxidation process. • Introduction environment friendly system for OMWW purification. • Highlight and clarification of efficiency of the electrocoagulation and advanced oxidation process simultaneously in purification oily wastewater. Abstract 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/dm2). 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. Graphical abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]

A new strategy in catalytic ozonation removal method for degradation and detoxification of phenol from industrial wastewater was investigated. Magnetic carbon nanocomposite, as a novel catalyst, was synthesized and then used in the catalytic ozonation process (COP) and the effects of operational conditions such as initial pH, reaction time, and initial concentration of phenol on the degradation efficiency and the toxicity assay have been investigated. The results showed that the highest catalytic potential was achieved at optimal neutral pH and the removal efficiency of phenol and COD is 98.5% and 69.8%, respectively. First-order modeling demonstrated that the reactions were dependent on the initial concentration of phenol, with kinetic constants varying from 0.038 min-1 ([phenol] o = 1500 mg/L) to 1.273 min-1 ([phenol]o = 50mg/L). Bioassay analysis showed that phenol was highly toxic to Daphnia magna (LC500 96 h = 5.6 mg/L). Comparison of toxicity units (TU) of row wastewater (36.01) and the treated effluent showed that TU value, after slightly increasing in the first steps of ozonation for construction of more toxic intermediates, severely reduced at the end of reaction (2.23). Thus, COP was able to effectively remove the toxicity of intermediates which were formed during the chemical oxidation of phenolic wastewaters. [ABSTRACT FROM AUTHOR]