In situ treatment of metalworking wastewater by chemical addition-dissolved air flotation coupled with UV, H2O2 & ZnO

The hybrid treatment techniques have been proven that could be a proper solution to the metalworking fluid (MWF) wastewaters disposal challenge. Hence, this investigation was conducted aim to the assessment of chemical addition-dissolved air floatation (CA-DAF) unit followed with a heterogeneous photocatalytic (PC) process as UV/H2O2/ZnO to treat MWF wastewater produced in one of the central industrial estates in the Middle East. The CA-DAF unit was implemented as trial and errors and had an appropriate efficiency. However, the environmental discharge standards were not achieved only by this unit, so that, a PC process considered for this purpose in a pilot-scale reactor. And also, Chemical oxygen demand (COD), total petroleum hydrocarbons (TPHs) were considered as physicochemical parameters to analyze the applied photochemical reaction throughout the concentrations of ZnO and H2O2, and pH value as variables of the study. The ideal and optimized conditions were observed at pH 10, 600 mg l(-1) of ZnO, and 13.11 g l(-1) of H2O2 via 99.87 and 97.9 reduction rates in total COD and TPH, respectively. These removal rates were obtained for this integrated strategy under the optimized reaction. By evaluating the synergistic effect, it was found that UV/ZnO could be a predominant reaction in this process. The organic and intermediates analysis appeared 78.46 reduction for all detected organic matters. Besides, PC generation of bis phthalate, mono phthalate, benzene, and benzoic acid to 2,6-bis (1,1-dimethylethyl)-4-mthyl phenol was the reason of the residual phenolic compound concentration in the reaction solution with low removal rate. The kinetic study showed that this reaction could be well fitted with the pseudo-first-order kinetic model by R (2) equal with 0.973 and 0.988 in turn for COD and TPH. The expenditures to treat 1 m(3) of the CA-DAF was estimated at 5.335 us via cost analysis. Finally, the collected findings indicate that CA-DAF integrated with UV/H2O2/ZnO can be an efficient approach in the MWF wastes disposal or treatment for reuse

Treatment of industrial wastewater contaminated with recalcitrant metal working fluids by the photo-Fenton process as post-treatment for DAF

Post-treatment of the industrial wastewater polluted by metalworking fluids (MWFs) was performed using the photo-Fenton process in following of the chemical addition-dissolved air flotation (CA-DAF) unit. Prior to this study, the CA-DAF was operated as full-scale by trial and error. For the photo-Fenton process as a pilot-scale batch reactor, initial pH value, FeSO4, and H2O2 concentrations were considered to study the effect of different operating conditions on chemical oxygen demand (COD) and total petroleum hydrocarbon (TPH) removals. This hybrid approach revealed removal efficiencies of 99.85 and 98.9 for COD and TPH in the optimized photo-Fenton process as pH 3, FeSO4: 100 mg/I, and H2O2: 17.8 The COD degradation results for the photo-Fenton system indicated that it could be well fit using a pseudo first order kinetic model. By the GC-MS analysis of DAF and applied photo-Fenton effluents, a 73 removal rate of mono(2-ethylhexyl) phthalate was detected. It is likely favorable to increase the biodegradability. The cost analysis of this process for the consumed energy (6 kWh) and chemicals (0.01818 kg FeSO4 and 17.15 kg H2O2) was estimated at approximately 26 per 1 m(3) of DAF effluent. Generally, these results imply that the CA-DAF unit followed by photo-Fenton is an effective and practical method for treating MWFs wastewater. (C) 2016 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved

A mini-review on new disinfection alternative: bacteriophages and pathogen removal potential from water and wastewater

Disinfection is a practice that inactivates and destroys pathogenic organisms. The conventional disinfectants for water and treated wastewater effluents have defects such as dangerous disinfection by-products, the resistance of bacteria and the related biofilms to disinfectant, high costs, no residual disinfecting action, and high risks involved in producing, transporting, and handling a large amount of chlorine and ozone. Accordingly, investigating new disinfection alternatives has been a necessity. Bacteriophages are used to treat a bacterial infection, which is known as phage therapy. In the recent decades, some studies revealed the role of phages in water and wastewater treatment, especially disinfection. In addition, the abundance of phages specific to enteric bacterial pathogens in natural water bodies is disclosed in many studies. This review discusses the phages specified to fecal coliform and other waterborne bacteria, the main advantages for applying the phages to reduce pathogens, restrictions of disinfection using phages, and the prospective applications of phages in order to improve the design and operation of the treatment plants