In this study, we investigated the potential applicability of monochloramine (MCA) for the control of membrane biofouling using a pilot-scale nanofiltration (NF) process in an advanced drinking water treatment process.It was found that membrane fouling was significantly mitigated and the increase of trans-membrane pressure was retarded more than three folds by the addition of 5 mg/L MCA.The analysis of membrane foulants after the autopsy revealed that the organic content was significantly decreased from 63.1% to 49.1% and most of the microorganisms were inactivated by the addition of MCA.Interestingly, the addition of MCA caused a dramatic decrease in protein compounds in extracellular polymeric substances extracted from biofilms, which hindered the development of dense biofilm structure.The addition of MCA also induced a significant change in the microbial community structures in the biofilm.In the presence of MCA, Alphaproteobacteria became the dominant class accounting for 59.8%, while Betaproteobacteria, which is the major bacterial community forming the biofilm in the membrane process, was decreased by 31.8%.Based on this study, the addition of MCA was effective in retarding the formation of biofilm on NF membrane surfaces by inactivating microorganisms and weakening the strength of biofilm structures.
In this study, a packed-bed dielectric barrier discharge (DBD) reactor was developed for particulate matter (PM) removal. The effects of operating conditions such as the packing materials, applied power, and discharging gap were systematically investigated. The results revealed that Zeolite 13X exhibited the highest PM removal efficiency based on its high electrostatic adsorption capacity. A narrow discharge gap (2.4 mm) and increased power density resulted in an enhancement of the PM removal efficiency in the system. Further, these operating conditions increased the electric field strength, which was proportional to the current density in the system. The energy yield decreased with an increase in the specific energy input into the packed-bed DBD reactor. Among the tested operating parameters, maintaining a narrow discharging gap was determined to be the most important for achieving high energy efficiency and PM removal in the system. Moreover, an air cleaning procedure was applied for the regeneration of the packing materials, resulting in a high recovery rate of over 80%.
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