1. Greenhouse gas emissions from membrane bioreactors: analysis of a two-year survey on different MBR configurations.
- Author
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Capodici, Marco, Cosenza, Alida, Di Trapani, Daniele, Mannina, Giorgio, Chandran, Kartik, and van Loosdrecht, Mark C. M.
- Subjects
GREENHOUSE gas analysis ,EMISSIONS (Air pollution) ,BIOREACTORS ,NITROUS oxide ,WASTEWATER treatment -- Environmental aspects - Abstract
This study aimed at evaluating the nitrous oxide (N
2 O) emissions from membrane bioreactors (MBRs) for wastewater treatment. The study investigated the N2 O emissions considering multiple influential factors over a two-year period: (i) different MBR based process configurations; (ii) wastewater composition (municipal or industrial); (iii) operational conditions (i.e. sludge retention time, carbon-to-nitrogen ratio, C/N, hydraulic retention time); (iv) membrane modules. Among the overall analysed configurations, the highest N2 O emission occurred from the aerated reactors. The treatment of industrial wastewater, contaminated with salt and hydrocarbons, provided the highest N2 O emission factor (EF): 16% of the influent nitrogen for the denitrification/nitrification-MBR plant. The lowest N2 O emission (EF = 0.5% of the influent nitrogen) was obtained in the biological phosphorus removal-moving bed-MBR plant likely due to an improvement in biological performances exerted by the co-presence of both suspended and attached biomass. The influent C/N ratio has been identified as a key factor affecting the N2 O production. Indeed, a decrease of the C/N ratio (from 10 to 2) promoted the increase of N2 O emissions in both gaseous and dissolved phases, mainly related to a decreased efficiency of the denitrification processes. [ABSTRACT FROM AUTHOR]- Published
- 2018
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