Full-scale application of partial nitritation and anammox in a single suspended-growth sequencing batch (SBR) reactor presented here confirm the process suitable for removing nitrogen from ammonium-rich wastewater with low concentrations of BOD and suspended solids: details of simple and robust process control based on online ammonium or conductivity signals are discussed by describing the full-scale startup at three municipal plants (five reactors in total). Ammonium oxidation rates of up to 500 gN m(-3) d(-1) with conversion to N2 of over 90% are achieved in a full-scale plant, but pilot results indicate that significantly higher rates are feasible. With continuous aeration at dissolved oxygen concentrations <1 mgO2 x L(-1), the nitrite oxidation and the anammox reaction occur simultaneously, allowing increased overall performance and simplified process control compared to separate aerobic end anaerobic phases (segregated either temporally or in different reactors). Sedimentation of the sludge requires special attention only during startup. Although the observed N2O emissions were slightly higher than in conventional nitrogen removal, the overall greenhouse gas emissions were lower, mainly due to energy-saving.

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Background: Conventional wastewater treatment plants discharge significant amounts of antibiotic resistant bacteria and antibiotic resistance genes into natural water bodies contributing to the spread of antibiotic resistance. Some advanced wastewater treatment technologies have been shown to effectively decrease the number of bacteria. Nevertheless, there is still a lack of knowledge about the effectiveness of these treatments on antibiotic resistant bacteria and antibiotic resistant genes. To the best of our knowledge, no specific studies have considered how powdered activated carbon (PAC) treatments can act on antibiotic resistant bacteria, although it is essential to assess the impact of this wastewater treatment on the spread of antibiotic resistant bacteria. </P><P> Methods: To address this gap, we evaluated the fate and the distribution of fluorescent-tagged antibiotic/ antimycotic resistant microorganisms in a laboratory-scale model simulating a process configuration involving powdered activated carbon as advanced wastewater treatment. Furthermore, we studied the possible increase of naturally existing antibiotic resistant bacteria during the treatment implementing PAC recycling. Results: The analysis of fluorescent-tagged microorganisms demonstrated the efficacy of the PAC adsorption treatment in reducing the load of both susceptible and resistant fluorescent microorganisms in the treated water, reaching a removal efficiency of 99.70%. Moreover, PAC recycling did not increase the resistance characteristics of cultivable bacteria neither in the sludge nor in the treated effluent. Conclusion: Results suggest that wastewater PAC treatment is a promising technology not only for the removal of micropollutants but also for its effect in decreasing antibiotic resistant bacteria release.

Syntrophy and interspecies electron transfer among different microbial groups occurs in anaerobic digestion, and many papers recently reported their positive effect on biogas and methane production. In this paper, we present the results on the effect of conductive material, i.e., graphene, PAC and biochar addition in 3.5 L batch experiments, analyzing the biogas production curve. A peculiar curve pattern occurred in the presence of conductive materials. Compared to the respective controls, the addition of graphene produced a biogas surplus of 33%, PAC 20% and biochar 8%. Microbial community molecular analysis showed that syntrophic microorganisms present in the inoculum were stimulated by the conductive material addition. Graphene also appears to promote an interspecies electron transfer between Geobacter sp. and ca. Methanofastidiosum. This paper contributes to the understanding of the DIET-related microbial community dynamic in the presence of graphene and PAC, which could be exploited to optimize biogas and methane production in real-scale applications.

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