Exploring GHG emissions in the mainstream SCEPPHAR configuration during wastewater resource recovery.

The wastewater sector paradigm is shifting from wastewater treatment to resource recovery. In addition, concerns regarding sustainability during the operation have increased. In this sense, many water utilities have become aware of the potential GHG emissions during the operation of wastewater treatment. This study assesses the nitrous oxide and methane emissions during the long-term operation of a novel wastewater resource recovery facility (WRRF) configuration: the mainstream SCEPPHAR. The long-term NO and CH emission factors calculated were in the low range of the literature, 1 % and 0.1 %, respectively, even with high nitrite accumulation in the case of NO. The dynamics and possible sources of production of these emissions are discussed. Finally, different aeration strategies were implemented to study the impact on the NO emissions in the nitrifying reactor. Results showed that operating the pilot-plant under different dissolved oxygen concentrations (between 1 and 3 g O m) did not have an effect on the NO emission factor. Intermittent aeration was the aeration strategy that most mitigated the NO emissions in the nitrifying reactor, obtaining a reduction of 40 % compared to the normal operation of the pilot plant.