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A pilot-scale investigation of ozonation combined with electrolysis (E-O3) was performed to treat concentrated wastewater from a reverse osmosis system from the printing and dyeing industry. It was found that E-O3 only exhibits an efficiency advantage after the removal of carbonate ions. The synergy of ozone and electrolysis lies not only in the generation of hydroxyl radicals, but also in the degradation of organic compounds. Moreover, the combination of electrolysis and ozonation has an inhibitory effect on the decrease in pH, which plays an important role in the synergistic generation of hydroxyl radicals. This pilot-scale study holds reference significance for the engineering applications of the E-O3 technology. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • O 3 -BAC was proven an appropriate technology for the removal of sulfonamides. • BAC overcame the problem of increased THMsFP and HAAsFP resulting from ozonation. • Sulfonamide-resistant bacteria would increase after BAC filtration. • The biological safety in the application of O 3 -BAC was highlighted. Abstract Removal of sulfonamides (SAs) by an integrated ozonation and biological activated carbon filtration (O 3 -BAC) process, as an advanced drinking water treatment process, was evaluated in a pilot-scale study. Furthermore, the effects of the O 3 -BAC process on sulfonamide-resistant bacteria (SRB) and on the removal of total organic carbon, UV 254 , and turbidity were investigated. Results indicate that ozonation could effectively remove SAs from water at an appropriate ozone dose with an improvement of water quality; however, BAC filtration would lead to an increase of SRB. In addition, the performance of the integrated process in eliminating disinfection byproducts formation potential (DBPsFP) in chlorination was evaluated. The results show ozonation would result in an increase of DBPsFP, while subsequent BAC filtration could effectively reduce DBPsFP to the safety-standard level of water quality. Overall, effective removal was achieved by the O 3 -BAC process in terms of the reduction of SAs but not of SRB. Subsequent disinfection is significant and biological safety should be evaluated further to ensure the effectiveness of the integrated process and the security of water quality. [ABSTRACT FROM AUTHOR]

Herein, micro-nano bubbles (MNBs) assisted ozonation process (O 3 /MNBs) was developed to enhance interfacial reactions for pollutant degradation. Notably, the removal of organic contaminants in O 3 /MNBs system was ultrafast over a wide pH range, much faster than that of macrobubbles ozonation process (O 3 /MaBs). Experimental observations suggested that MNBs can effectively accelerate O 3 interfacial mass transfer and enrich abundant OH− from a bulk solution, thus inducing high concentrations of O 3 and hyperaccumulation of OH− ions at gas-liquid interface. These interfacial characteristics of MNBs resulted in formation of a special interfacial reaction field, in which high concentration of O 3 can be quickly activated by hyperaccumulated OH− ions along with assistance of energy released by MNBs collapse, ultimately boosting •OOH generation significantly. In addition, •OOH/•O 2 - performed as critical intermediates for the formation of •OH in O 3 /MNBs process. O 3 /MNBs system demonstrated favorable and steady performance during long-term advanced treatment of industrial wastewater (∼7 m3/h) with significantly lower ΔO 3 /ΔCOD (1.41) than O 3 /MaBs system (2.69). The pilot-scale demonstration of O 3 /MNBs efficiently degraded all four categories of organic contaminants according to EEM fluorescence spectra. The study demonstrated an environmentally-benign technology for effective treatment of industrial wastewater. [Display omitted] • Interfacial reaction fields are formed in O 3 /micro-nano bubbles (MNBs) system. • Micro-nano bubbles boost •OOH generation significantly. • •OOH performs as critical intermediates for •OH formation in O 3 /MNBs process. • O 3 /MNBs system performs well for pollutants degradation over a wide pH range • O 3 /MNBs display ultrafast industrial wastewater treatment with lower ΔO 3 /ΔCOD. [ABSTRACT FROM AUTHOR]