0000000000225857
AUTHOR
N. Zamorano-lópez
Co-digestion of harvested microalgae and primary sludge in a mesophilic anaerobic membrane bioreactor (AnMBR): Methane potential and microbial diversity
Abstract Anaerobic co-digestion of primary sludge and raw microalgae (Scenedesmus and Chlorella) was performed in a lab-scale semi-continuous anaerobic membrane bioreactor to assess the biological performance and identify the microbial community involved in the co-digestion process. The reactor was operated at 35 °C for 440 days, working at a solids retention time of 100 days. The system achieved 73% biodegradability and showed high stability in terms of pH and volatile fatty acids. An enriched microbial community was observed. Of the several phyla, Chloroflexi and Proteobacteria were the most abundant. Cellulose-degraders phyla (Bacteroidetes, Chloroflexi and Thermotogae) were detected. Sy…
Resource recovery from sulphate-rich sewage through an innovative anaerobic-based water resource recovery facility (WRRF)
[EN] This research work proposes an innovative water resource recovery facility (WRRF) for the recovery of energy, nutrients and reclaimed water from sewage, which represents a promising approach towards enhanced circular economy scenarios. To this aim, anaerobic technology, microalgae cultivation, and membrane technology were combined in a dedicated platform. The proposed platform produces a high-quality solid- and coliform-free effluent that can be directly discharged to receiving water bodies identified as sensitive areas. Specifically, the content of organic matter, nitrogen and phosphorus in the effluent was 45 mg COD.L-1 , 14.9 mg N.L-1 and 0.5 mg P.L-1 , respectively. Harvested solar…
Unveiling microbial structures during raw microalgae digestion and co-digestion with primary sludge to produce biogas using semi-continuous AnMBR systems
[EN] Methane production from microalgae can be enhanced through anaerobic co-digestion with carbon-rich substrates and thus mitigate the inhibition risk associated with its low C:N ratio. Acclimated microbial communities for microalgae disruption can be used as a source of natural enzymes in bioenergy production. However, co-substrates with a certain microbial diversity such as primary sludge might shift the microbial structure. Substrates were generated in a Water Resource Recovery Facility (WRRF) and combined as follows: Scenedesmus or Chlorella digestion and microalgae co-digestion with primary sludge. The study was performed using two lab-scale Anaerobic Membrane Bioreactors (AnMBR). Du…
Influence of food waste addition over microbial communities in an Anaerobic Membrane Bioreactor plant treating urban wastewater
[EN] Notorious changes in microbial communities were observed during and after the joint treatment of wastewater with Food Waste (FW) in an Anaerobic Membrane Bioreactor (AnMBR) plant. The microbial population was analysed by high-throughput sequencing of the 16S rRNA gene and dominance of Chloroflexi, Firmicutes, Synergistetes and Proteobacteria phyla was found. The relative abundance of these potential hydrolytic phyla increased as a higher fraction of FW was jointly treated. Moreover, whereas Specific Methanogenic Activity (SMA) rose from 10 to 51 mL CH4 g(-1) VS, Methanosarcinales order increased from 34.0% over 80.0% of total Archaea, being Methanosaeta the dominant genus. The effect o…
Effect of long residence time and high temperature over anaerobic biodegradation of Scenedesmus microalgae grown in wastewater
[EN] Anaerobic digestion of indigenous Scenedesmus spp. microalgae was studied in continuous lab-scale anaerobic reactors at different temperatures (35 degrees C and 55 degrees C), and sludge retention time - SRT (50 and 70 days). Mesophilic digestion was performed in a continuous stirred-tank reactor (CSTR) and in an anaerobic membrane bioreactor (AnMBR). Mesophilic CSTR operated at 50 days SRT only achieved 11.9% of anaerobic biodegradability whereas in the AnMBR at 70 days SRT and 50 days HRT reached 39.5%, which is even higher than the biodegradability achieved in the thermophilic CSTR at 50 days SRT (30.4%). Microbial analysis revealed a high abundance of cellulose-degraders in both re…
Exploring the limits of anaerobic biodegradability of urban wastewater by AnMBR technology
[EN] Anaerobic membrane bioreactors (AnMBRs) can achieve maximum energy recovery from urban wastewater (UWW) by converting influent COD into methane. The aim of this study was to assess the anaerobic biodegradability limits of urban wastewater with AnMBR technology by studying the possible degradation of the organic matter considered as non-biodegradable as observed in aerobic membrane bioreactors operated at very high sludge retention times. For this, the results obtained in an AnMBR pilot plant operated at very high SRT (140 days) treating sulfate-rich urban wastewater were compared with those previously obtained with the system operating at lower SRT (29 to 70 days). At 140 days SRT the …
Acclimatised rumen culture for raw microalgae conversion into biogas: Linking microbial community structure and operational parameters in anaerobic membrane bioreactors (AnMBR)
[EN] Ruminal fluid was inoculated in an Anaerobic Membrane Reactor (AnMBR) to produce biogas from raw Scenedesmus. This work explores the microbial ecology of the system during stable operation at different solids retention times (SRT). The 16S rRNA amplicon analysis revealed that the acclimatised community was mainly composed of Anaerolineaceae, Spirochaetaceae, Lentimicrobiaceae and Cloacimonetes fermentative and hydrolytic members. During the highest biodegradability achieved in the AnMBR (62%) the dominant microorganisms were Fervidobacterium and Methanosaeta. Different microbial community clusters were observed at different SRT conditions. Interestingly, syntrophic bacteria Gelria and …
Thermophilic anaerobic conversion of raw microalgae: Microbial community diversity in high solids retention systems
[EN] The potential of microbial communities for efficient anaerobic conversion of raw microalgae was evaluated in this work. A long-term operated thermophilic digester was fed with three different Organic Loading Rates (OLR) (0.2, 0.3 and 0.4¿g·L¿1·d¿1) reaching 32¿41% biodegradability values. The microbial community analysis revealed a remarkable presence of microorganisms that exhibit high hydrolytic capabilities such as Thermotogae (~44.5%), Firmicutes (~17.6%) and Dictyoglomi, Aminicenantes, Atribacteria and Planctomycetes (below ~5.5%) phyla. The suggested metabolic role of these phyla highlights the importance of protein hydrolysis and fermentation when only degrading microalgae. The …
Effect of sludge age on microbial consortia developed in MFCs
BACKGROUND This work is focused on the assessment of the performance of mini-scale air-breathing microbial fuel cells (MFCs), by monitoring the evolution of the bio-electrogenic activity for a period of 40 days and by comparing the microorganisms populations developed in each of the MFC after this period. RESULTS Five MFCs were operated at sludge ages ranging from 1.4 to 10.0 days. Results showed the superb performance of the MFC operating under a sludge age of 2.5 days. Desulfuromonas, Syntrophothermus, Solitalea, Acholeplasma, Propionicimonas, Desulfobacula and Sphaerochaeta are proposed as potential responsible for the bio-electrogenic activity. CONCLUSIONS Microbial population analysis …
Understanding the performance of an AnMBR treating urban wastewater and food waste via model simulation and characterization of the microbial population dynamics
[EN] An anaerobic membrane bioreactor (AnMBR) pilot plant treating kitchen food waste (FW) jointly with urban wastewater was run for 536 days. Different operational conditions were tested varying the sludge retention time (SRT), the hydraulic retention time (HRT) and the penetration factor (PF) of food waste disposers. COD removal efficiency exceeded 90% in all tested conditions. The joint treatment resulted in an almost 3-fold increase in methane production (at 70 days of SRT, 24 h HRT and 80% PF) in comparison with the treatment of urban wastewater only. Mathematical model simulations and Illumina technology were used to obtain in-depth information of this outstanding process performance.…