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Aerobic granular sludge reactors usually operate in sequential batch mode, although this configuration limits the treatment of large volumes of wastewater, and they require a storage system. To implement this technology at full-scale, it would be necessary to design a simple and compact continuous-flow bioreactor able to treat larger volumes of wastewater. In this study, four aerobic granular sludge single-chamber continuous-flow reactors (R1, R2, R3 and R4) were designed and operated at the lab scale to evaluate and select a bioreactor configuration that achieves high organic matter removal performance while maintaining a stable granulation for long-term operation, promoting the washout of filamentous microorganisms. Results confirmed that the bioreactor including a lateral decanter (R1), was able to work in a steady state without loss of granular biomass and reached 95% of organic matter removal performance. Its granules had excellent compaction, with settling velocity values above 100 m⋅h− 1 . The R1 bioreactor also allowed rapid biomass adaptation and therefore a fast start-up (11 days). Results of this preliminary study at the lab scale suggested that the new and simple bioreactor design could be promising for its implementation at full scale. For that, future research is required to optimise the current model and to determine the most suitable operational parameters to treat domestic wastewater at full scale., This work was supported by the Programa operativo FEDER de Andalucía 2014–2020 (Junta de Andalucía y Union ´ Europea) with reference B-RNM-137-UGR18., This work was supported by the Programa operativo FEDER de Andalucía 2014–2020 (Junta de Andalucía y Unión Europea) with reference B-RNM-137-UGR18.

The detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during wastewater treatment leads to concerns about whether this process may represent a focal point for the transmissi...

A sequential bed granular bioreactor was adapted to treat nitrate-polluted synthetic groundwater under anaerobic conditions and agitation with denitrification gas, achieving very efficient performance in total nitrogen removal at influent organic carbon concentrations of 1 g L-1 (80–90%) and 0.5 g L-1 (70–80%) sodium acetate, but concentrations below 0.5 g L-1 caused accumulation of nitrite and nitrate and led to system failure (30–40% removal). Biomass size and settling velocity were higher above 0.5 g L-1 sodium acetate. Trichosporonaceae dominated the fungal populations at all times, while a dominance of terrestrial group Thaumarchaeota and Acidovorax at 1 and 0.5 g L-1 passed to a domination of Methanobrevibacter and an unclassified Comamonadaceae clone for NaAc lower than 0.5 g L-1. The results obtained pointed out that the denitrifying granular sludge technology is a feasible solution for the treatment of nitrogen-contaminated groundwater, and that influent organic matter plays an important role on the conformation of microbial communities within it and, therefore, on the overall efficiency of the system.

Supplementary data associated with this article can be found in the online version at doi:10.1016/j.jece.2023.109527, Aerobic Granular Biomass (AGB) technology is widely used for urban and industrial wastewater treatment, however, its application in groundwater remediation, is practically unknown. A mixture of carbendazim, simazine, and diuron were amended to the nitrate-polluted synthetic groundwater at increasing concentrations to validate the ability of technology to remove both kind of pollutants, pesticides and nitrate which are commonly found in the water resources. The nitrate removal was a success with values below 0.010 g⋅L-1. The increased concentration of pesticides in the influent did not distort the pattern observed for pesticide removal. Carbendazim was almost completely eliminated, followed by simazine elimination, while diuron showed adsorption-desorption patterns during experimentation. The addition of pesticides had a drastic effect on the basal community conducted by proliferation of Hyphomicrobium and Dokdonella. The pesticide compounds had a negative effect on number of copies for fungal population, while archaeal population was unharmed, according to qPCR results. Denitrifying bacteria need 70 days as acclimatization period for achieving activity values as initial inoculum. The results obtained have shown for the first time the capacity of AGB system to treat groundwater polluted with nitrate and pesticide using low carbon load. Therefore, the results suggested the potential application of AGB technology for the purification of groundwater polluted with both nitrates and pesticides, Project LIFE16 ENV/ES/000196, European LIFE Program and B-RNM-137-UGR18, Programa operativo FEDER de Andalucía 2014-2020, Department of Ecological and Biological Sciences of University of Tuscia, group RNM270 of Institute of Water Research (University of Granada), Barbara summaUnion-NextGenerationEU, Universidad de Granada / CBUA

Granular activated sludge has been described as a promising tool in treating wastewater. However, the effect of high concentrations of sulphur amino acids, cysteine and methionine, in the evolution, development and stability of AGS-SBRs (aerobic granular sludge in sequential batch reactors) and their microbial communities is not well-established. Therefore, this study aimed to evaluate microbial communities' size, structure and dynamics in two AGS-SBRs fed with two different concentrations of amino acids (50 and 100 mg L− 1 of both amino acids). In addition, the impact of the higher level of amino acids was also determined under an acclimatization or shock strategy. While N removal efficiency decreased with amino acids, the removal of the organic matter was generally satisfactory. Moreover, the abrupt presence of both amino acids reduced even further the removal performance of N, whereas under progressive adaptation, the removal yield was higher. Besides, excellent removal rates of cysteine and methionine elimination were found, in all stages below 80% of the influent values. Generally considered, the addition of amino acids weakly impacts the microbial communities' total abundances. On the contrary, the presence of amino acids sharply modulated the dominant bacterial structures. Furthermore, the highest amino acid concentration under the shock strategy resulted in a severe change in the structure of the microbial community. Acidovorax, Flavobacterium, Methylophilus, Stenotrophomonas and Thauera stood out as the prominent bacteria to cope with the high presence of cysteine and methionine. Hence, the AGS-SBR technology is valuable for treating influents enriched in sulphur Aa inclusively when a shock strategy was used., Spanish Ministry of Education and Professional Fomation,FPU programme, Carolina Foundation, National Health and Medical Research Council (NHMRC) of Australia, German Research Foundation (DFG), Aurora Rosa-Masegosa, Universidad de Granada/CBUA

The present work aims to use aerobic granular sludge technology for the treatment of wastewater containing high organic matter loads and a mixture of phenolic compounds normally present in olive washing water. The physicochemical performance of five bioreactors treating different concentrations of mixture of phenolic acid was monitored to observe the response of the systems. The bioreactors that operated at 50, 100 and 300 mg L−1 did not show relevant changes in terms of performance and granules properties, showing high ratio of phenolic compound removal ratio. However, the bioreactors operated with high phenolic compound concentrations showed low rates of organic matter, nitrogen and phenolic acid removal. In the same way, high concentrations of phenolic compounds determined the disintegration of the granular biomass. Next-generation sequencing studies showed a stable community structure in the bioreactors operating with 50, 100 and 300 mg L−1 of phenolic acids, with the genera Lampropedia and Arenimonas, family Xanthobacteraceae and Fungi Pezizomycotina as the dominant phylotypes. Conversely, the reactors operated at 500 and 600 mg L−1 of phenolic substances promoted the proliferation of Oligohymenophorea ciliates. Thus, this study suggests that aerobic granular sludge technology could be useful for the treatment of wastewaters such as olive washing water.

The aim of this work was to study the operational performance and the microbial community dynamics during the start-up of ANITATMMox technology implemented at full-scale wastewater treatment plant in Finland to treat reject water from anaerobic digesters. The average ammonium removal in the studied setup reached around 90%, withstanding ammonium loads up to 0.13 g N m-2h-1. The nitrite concentration in the effluent did not exceed 10 mg L-1, and there was a slight accumulation of NO3--N during the operation which was controlled. Thus, the result showed a robust success to high ammonium loading in presence of organic matter. The sequencing showed a heterogeneous microbial population where Methanosaeta, WCHA1-57 genus, Sphingobacteriia, Chlorobia and diverse unknown fungi were found as dominant phylotypes. Moreover, members of the Brocadiaceae family were dominant in the adhered biomass, mostly represented by Candidatus Scalindua, rarely reported in WWTPs. Overall, the results demonstrated a drastic effect of region-specific operational conditions on carrier biofilm microbial communities as it was demonstrated by the microbial studies.

Four granular sequencing batch reactors (GSBRs) were inoculated with four denitrifying Pseudomonas strains carrying nosZ to study the process of granule formation, the operational conditions of the bioreactors, and the carbon concentration needed for nitrate removal. The selected Pseudomonas strains were P. stutzeri I1, P. fluorescens 376, P. denitrificans Z1, and P. fluorescens PSC26, previously reported as denitrifying microorganisms carrying the nosZ gene. Pseudomonas denitrificans Z1 produced fluffy, low-density granules, with a decantation speed below 10 m h−1 . However, P. fluorescens PSC26, P. stutzeri I1, and P. fluorescens 376 formed stable granules, with mean size from 7 to 15 mm, related to the strain and carbon concentration. P. stutzeri I1 and P. fluorescens 376 removed nitrate efficiently with a ratio in the range of 96%, depending on the source and concentration of organic matter. Therefore, the findings suggest that the inoculation of GSBR systems with denitrifying strains of Pseudomonas spp. containing the nosZ gene enables the formation of stable granules, the efficient removal of nitrate, and the transformation of nitrate into nitrogen gas, a result of considerable environmental interest to avoid the generation of nitrous oxide., LIFE16 ENV/ES/000196 project

The authors would like to acknowledge the support given by the Institute of Water Research of University of Granada and the disposition of Municipal Water Company of Granada (EMASAGRA S.A.) for financial support to carry out the research., In wastewater treatment plants, most microbial characterization has focused on bacterial, archaeal, and fungal populations. Due to the difficult isolation, quantification, and identification of viruses, only a limited number of virome studies associated with wastewater treatment plants have been carried out. However, the virus populations play an important role in the microbial dynamics in wastewater treatment systems and the biosafety of effluents. In this work, the viral members present in influent wastewater, mixed liquor (aerobic bioreactor), excess sludge, and effluent water of a conventional activated sludge system for the treatment of urban wastewater were identified. Viral members were observed by transmission electron microscopy and studied through next-generation sequencing studies. The results showed the dominance of bacteriophages in the viral community in all samples, with the dominant viral phylotype classified as Escherichia coli O157 typing phage 7. Moreover, different human viruses, such as Cynomolgus cytomegalovirus and Gammaherpesvirus, were also detected., Institute of Water Research of University of Granada

The aim of this work was to study the performance and microbial community structure of a polar Arctic Circle aerobic granular sludge (AGS) system operating at low temperature. Thus, an AGS bioreactor was operated at 7, 5 and 3 °C of temperature using a cold-adapted sludge from Lapland. At 5 °C, it yielded acceptable conversion rates, in terms of nitrogen, phosphorous, and organic matter. However, under 3 °C a negligible nitrogen and phosphorous removal performance was observed. Below 5 °C, scanning electron microscopy studies showed a wispy, non-dense and irregular granular structure with a strong outgrowth of filamentous. Moreover, Illumina next-generation sequencing showed a heterogeneous microbial population where SM1K20 (Archaea), Trichosporon domesticum (Fungus), and Zooglea, Arcobacter and Acinetobacter (Bacteria) were the dominant phylotypes. Our study suggests that AGS technologies inoculated with North Pole sludge could be operated, in cold regions for a period longer than 3 months (winter season) under 5 °C of water temperature.

Autotrophic nitrogen removal systems have been implemented at full-scale and provide an efficient way for nitrogen removal from industrial and urban wastewaters. Our study present qualitative and quantitative analysis of archaeal and bacterial amoA genes and Candidatus Brocadiales bacteria analyzed in six full-scale autotrophic nitrogen removal bioreactors. The results showed that Ammonium Oxidizing Bacteria (AOB) were detected in all bioreactors. However, Ammonium Oxidizing Archaea (AOA) were detected only in the non-aerated technologies. On the other hand, different Candidatus Brocadiales phylotypes appeared due to differences in influent wastewater composition and hydraulic retention time (HRT). In the same terms multivariate redundancy analysis confirmed that AOA was positively correlated with temperature, ammonium concentration and low HRT. However, AOB population was positively correlated with pH, temperature and dissolved oxygen concentration. Our data suggested a correlation between the microorganisms involved in the nitrogen removal performance and the operational conditions in the different full-scale bioreactors. This article is protected by copyright. All rights reserved.

Three lab-scale sequential batch reactors were operated under aerobic granular sludge technology for 150 days. The reactors were inoculated with mild temperature-adapted activated sludge from Granada wastewater treatment plant (WWTP) in order to evaluate the microbial dynamics, the granulation process and the performance of the systems under low, mid and high temperature. The faster start-up was achieved at mid temperature at operational day 6, followed by warm temperature at day 10, with nitrogen and organic matter removal ratio higher than 90%. Conversely, the reactor under cold temperature produced granular biomass but the nitrogen and carbon removal ratios did not achieve good performance, close to 80%. The dynamics of Prokarya communities showed that Corynebacterium phylotype was present in all bioreactor despite temperature, although the microbial diversity at mid and warm temperature was higher than at cold temperature. The Eukarya communities in mature granules were represented by Pezizomycotina fungi and Oligohymenophorea ciliate.

Three bioreactors were inoculated with Polar Arctic Circle-activated sludge, started-up and operated for 150 days at 8, 15 and 26 °C. Removal performances and granular conformation were similar at steady-state, but higher stability from start-up was found when operating at 8 °C. Important changes in the eukaryotic and prokaryotic populations caused by operational temperature were observed, being fungi dominant at 8 °C and 15 °C, while that ciliated organisms were found at 26 °C. The qPCR results showed higher copies of bacteria, and nitrifiers and denitrifying bacteria at cold temperature. The emission of nitrous oxide was linked directly with temperature and the involved microorganisms. This study represents a proof of concept in performance, greenhouse gas emission, granular formation and the role of the Polar Arctic Circle microbial population in AGS technology under different temperatures with the aim to understand the effect of seasonal o daily changes for implementation of AGS at full-scale.

The authors would like to acknowledge the support given by the Institute of Water Research of the University of Granada, Spain and Universita degli Studi della Tuscia, Italy., Aerobic granular sludge (AGS) comprises an aggregation of microbial cells in a tridimensional matrix, which is able to remove carbon, nitrogen and phosphorous as well as other pollutants in a single bioreactor under the same operational conditions. During the past decades, the feasibility of implementing AGS in wastewater treatment plants (WWTPs) for treating sewage using fundamentally sequential batch reactors (SBRs) has been studied. However, granular sludge technology using SBRs has several disadvantages. For instance, it can present certain drawbacks for the treatment of high flow rates; furthermore, the quantity of retained biomass is limited by volume exchange. Therefore, the development of continuous flow reactors (CFRs) has come to be regarded as a more competitive option. This is why numerous investigations have been undertaken in recent years in search of different designs of CFR systems that would enable the effective treatment of urban and industrial wastewater, keeping the stability of granular biomass. However, despite these efforts, satisfactory results have yet to be achieved. Consequently, it remains necessary to carry out new technical approaches that would provide more effective and efficient AGS-CFR systems. In particular, it is imperative to develop continuous flow granular systems that can both retain granular biomass and efficiently treat wastewater, obviously with low construction, maintenance and exploitation cost. In this review, we collect the most recent information on different technological approaches aimed at establishing AGS-CFR systems, making possible their upscaling to real plant conditions. We discuss the advantages and disadvantages of these proposals and suggest future trends in the application of aerobic granular systems. Accordingly, we analyze the most significant technical and biological implications of this innovative technology., Institute of Water Research of the University of Granada, Spain, Universita degli Studi della Tuscia, Italy

A pilot-scale anammox biofilter was set up and operated using reject water in order to investigate its nitrogen removal performance and the microbial community present at different stages of operation of this technology. A novel material “Filtralite” was used a support in order to achieve shorter start-up periods and obtain higher nitrogen load removal than other anammox technologies. Physico-chemical analysis demonstrated that nitrogen removal efficiency was higher than 70% from operational Day 100, reaching steady-stable total nitrogen removal and NH4+-N of 82% and 91%, respectively, this results suggest the robustness and adaptability of the technology to withstand changing nitrogen loads in the influent. Molecular analysis showed the presence of Nitrosomonas and Candidatus Brocadiales with relative abundance on different key days at around 2.5% of total relative abundance, although other phylotypes involved in the nitrogen cycle were also found. RT-PCR analysis showed that the pre-seed Filtralite used promoted the occurrence of anammox bacteria and other ammonia-oxidizing bacteria. The eukaryotic community oscillated greatly during operation and did not show any clear pattern. Both Prokarya and Eukarya showed high diversity and evenness, attributes which were very stable during operation. The biofilter performed robustly, despite changes in influent and nitrogen load, validating its suitability for treating industrial or urban effluent with high nitrogen loading in order to avoid damages in the environment in the save-cost way.

Enterobacteriaceae is present in various niches worldwide (i.e., the gastrointestinal tracts of animals, clinical specimens, and diverse environments) and hosts some well-known pathogens (i.e., salmonellas, shigellas and pathogenic coliforms). No investigation has focused on its occurrence in marine salterns, and it is not clear if these hypersaline environments could be a reservoir for these bacteria including some potentially harmful members. In this study, a two-year metabarcoding survey was carried out on samples collected from different ponds of the “Saline di Tarquinia” salterns and the nearby coastal waters. Enterobacteriaceae was recorded almost constantly in the seawaters feeding the saltern. Its abundance was generally higher in the sea than in the ponds, probably due to the higher anthropic impact. The same trend was evidenced for the key genus (Escherichia/Shigella) and OTU (OTU 5) of the Enterobacteriaceae community. Various parameters affected taxon/OTU abundance: Enterobacteriaceae, Escherichia/Shigella and OTU5 decreased with increasing salinity and rains, moreover, Escherichia/Shigella and OTU 5 were higher in autumn than in spring. Although Enterobacteriaceae did not seem to find the most favourable conditions for a high-abundance persistence in the saltern environment, it did not disappear. These observations suggested this environment as a potential reservoir for bacteria with possible important health implications.

Granular aerobic sludge systems have been a very efficient technology in urban and industrial wastewater treatment. In this research, a novel modification of aerobic granular sludge technology was developed for the treatment of nitrate-polluted groundwater, adding very low concentrations of a solution based on carbon and oligoelements in the groundwater to promote the growth of denitrifying microorganisms, avoiding expensive technologies to supply drinking water in small urban nuclei. The denitrification process was successfully reached at 0.15 g C2H3NaO2 L−1, meeting the Nitrate Directive of Europe for drinking water. The granular biomass was compact and dense with average values of mean size and settling velocity of 4.0 mm and 40 mh−1, respectively. The prokaryotic and eukaryotic communities were studied by massive parallel sequencing techniques. The dominant prokaryotic phylotypes were related to influent composition, belonging to Comamonadaceae, Rhizobiales, Acinetobacter and Pseudomonas. The dominant eukaryotic phylotype was affiliated to Haematococcus microalgae. The diversity and evenness were high, regardless of influent composition. This study demonstrates support for the innovation of aerobic granular sludge technology application in terms of performance, operation, granular maturation and stability, as well as the role of denitrifying microorganisms to implement a low-cost, easy-to-use and maintain, environmental-friendly drinking water technology for rural populations.

Biofouling significantly reduces the performance efficiency of membrane bioreactors due to the colonization and accumulation of a matrix of microorganisms. In order to investigate the effect of ultrasonic frequency on biofilm formation and bacterial ecology at different frequencies, four microfiltration membrane modules were subjected at 0, 20, 30 and 40 kHz in pilot-scales. The results of massive parallel sequencing showed that the application of ultrasonic frequency significantly affected the bacterial population in biofouling and modifies the species richness even at low frequency. This research reveals that the application of ultrasonic frequencies avoids the colonization of Acinetobacter genus, which is considered an initial colonizer of biofouling and clogging in the submerged membrane reactor, fact that caused problems in full-scale wastewater treatment plant. The promotion of Gordonia genus was observed during the application of any ultrasounds frequencies (20,30 and 40 Hz). The compositional statistics data exposed the similarity of bacterial communities under medium-high ultrasonic frequency, while those great distances were found in both low and no-ultrasounds frequencies apply. These results suggest that the application of ultrasounds in membrane bioreactor for treating wastewater could be effective in the potential reduction of biofouling formation in order to improve the to improve the useful life of this system with short periods of application of ultrasound.

A lab-scale partial nitritation SBR was operated at 11 °C for 300 days used for the treatment of high-ammonium wastewater, which was inoculated with activated sludge from Rovaniemi WWTP (located in Polar Arctic Circle) in order to evaluate the influence the temperature on the performance, stability and dynamics of its microbial community. The partial nitritation achieved steady-state long-term operation and granulation process was not affected despite the low temperature and high ammonia concentration. The steady conditions were reached after 60 days of operation where the granular biomass was fully-formed and the 50%–50% of ammonium-nitrite effluent was successful achieved. Inoculation with cold adapted inoculum showed to yield bigger, denser granules with faster start-up without necessity of low temperature adaptation period. Next-generation sequences techniques showed that Trichosporonaceae and Xanthomonadaceae were the dominant OTUs in the mature granules. Our study could be useful in the implementation of full-scale partial nitritation reactors in cold regions such as Nordic countries for treating wastewater with high concentration of ammonium.

Two hybrid moving bed biofilm reactor-membrane bioreactors were used for the treatment of variable-salinity influent wastewater with maximums of 4.5 and 8.5 mS cm−1 electric conductivity. Operational conditions of the bioreactors were 6 h hydraulic retention time and 2500 mg L−1 total solids. The membrane operated in a cycle of 9 min draw-1 min backwash and at 23.6 L h−1 m−2 flux rate. Membrane biofilm was collected from both systems and cultured in growth media for precipitation of carbonate and phosphate minerals, yielding only Bacillus stratosphericus for the 4.5 mS cm−1 scenario and Bacillus stratosphericus, Bacillus toyonensis, Microbacterium esteraromaticum, Comamonas testosteroni, and Janibacter meloni for the 8.5 mS cm−1 scenario. Scanning electron microscopy and X-ray analysis showed similarities in morphology and composition for the carbonate crystals from both salinity conditions and differences for the phosphate minerals. Study of the bacterial community of membrane biofilm and mixed liquor showed close similarities between them for the same salinity conditions, with both dominated by genera Rhodanobacter, Chujaibacter, and Thermomonas.

A membrane bioreactor and two hybrid moving bed bioreactor-membrane bioreactors were operated for the treatment of variable salinity wastewater, changing in cycles of 6-h wastewater base salinity and 6-h maximum salinity (4.5 and 8.5 mS cm−1 electric conductivity, which relate to 2.4 and 4.8 g L−1 NaCl, respectively), under different hydraulic retention times (6, 9.5, and 12 h) and total solids concentrations (2500 and 3500 mg L−1). The evaluation of the performance of the systems showed that COD removal performance was unaffected by salinity conditions, while BOD5 and TN removals were significantly higher in the low-salinity scenario. The microbial community structure showed differences with respect to salinity conditions for Eukarya, suggesting their higher sensitivity for salinity with respect to Prokarya, which were similar at both salinity scenarios. Nevertheless, the intra-OTU distribution of consistently represented OTUs of Eukarya and Prokarya was affected by the different salinity maximums. Multivariate redundancy analyses showed that several genera such as Amphiplicatus (0.01–5.90%), Parvibaculum (0.27–1.19%), Thiothrix (0.30–1.19%), Rhodanobacter (2.81–5.85%), Blastocatella (0.21–2.01%), and Nitrobacter (0.80–0.99%) were positively correlated with BOD5 and TN removal, and the ecological roles of these were proposed. All these genera were substantially more represented under low-salinity conditions (10–500% higher relative abundance), demonstrating that they might be of importance for the treatment of variable salinity wastewater. Evaluation of Eukarya OTUs showed that many of them lack a consistent taxonomic classification, which highlights the lack of knowledge of the diversity and ecological role of Eukaryotes in saline wastewater treatment processes. The results obtained will be of interest for future design and operation of salinity wastewater treatment systems particularly because little is known on the effect of variable salinity conditions in wastewater treatment.

In this study, a lab-scale CANON bioreactor was operated for 260 days, decreasing operational temperature from 35 °C to 15 °C and from 466 to 100 mg-N L−1 ammonium. This was done in order to check the feasibility of the acclimation of CANON biomass treating anaerobic digestion supernatant to B-stage influent wastewater operational conditions. Results showed that decrease in temperature posed an impact over the performance of the CANON bioreactor as well as over its bacterial assemblage. Nitrogen removal efficiency showed a moderate decrease when the system was acclimated from 35 °C to 25 °C, but it decreased dramatically in the acclimation from 25 °C to 15 °C. The decrease in temperature and influent ammonium concentration posed an impact over the bacterial community structure of the system. Ammonium oxidizing bacteria changed from Nitrosomonas, Nitrosospira or Nitrosovibrio genera at high temperature and influent ammonium to Prosthecobacter at low temperature and low ammonium. As well, dominant anammox bacteria genus changed from Candidatus Brocadia to Candidatus Anammoxoglobus during acclimation. Proliferation of nitrite oxidizing bacteria only occurred under low temperature and influent ammonium conditions with growth of Rhodanobacter genus.

Partial-nitritation processes are used for the biological treatment of high nitrogen-low organic carbon effluents, such as anaerobic digestion reject water. The release of certain products generated during the anaerobic digestion process, such as amino acids, could potentially reduce the performance of these partial-nitritation bioprocesses. To investigate this, four partial-nitritation biofilters were subjected to continuous addition of 0, 150, 300, and 500 mg L-1 cysteine amino acid in their influents. The addition of the amino acid had an impact over the performance of the partial-nitritation process and the bacterial community dynamics of the systems analyzed. Ammonium oxidation efficiency decreased with the addition of the amino acid, and a net nitrogen elimination occurred in presence of cysteine through the operation period. Bacterial community dynamics showed a decrease of Nitrosomonas species and a proliferation of putative heterotrophs with nitrification capacity, such as Pseudomonas, or denitrification capacity, such as Denitrobacter or Alicycliphilus. The addition of cysteine irreversible affected the bioreactors, which could not achieve the performance obtained before the addition of the amino acid. A mathematical predictive equation of the process performance depending on cysteine concentration added and operational time under such concentration was developed. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1254-1263, 2016.

A partial-nitritation biofilter was tested in order to investigate the effect of organic matter loading over its performance and bacterial community structure. Analyses were done after each of a two-step organic loading of 45 days each. Without organic matter addition, the partial-nitritation biofilter performed in nearly ideal conditions in terms of ammonium oxidation to nitrite. Under these conditions its bacterial community structure was dominated by Nitrosomonas bacteria. The first loading of organic matter caused a decrease in ammonium oxidation as well as decrease in relative abundance of Nitrosomonas . The COD and BOD 5 removal increased with the operation time up to 85% and 81%. For the second loading of organic matter the partial-nitritation biofilter achieved 91% and 97% in COD and BOD 5 removal at the end of the experimental period but ammonium oxidation efficiency was still inefficient. The changes in the bacterial community structure of the biofilter were more pronounced at the first organic loading step as suggested by α- and β-diversity analyses. In this way, the partial-nitritation biofilter could not achieve the desired coupled ammonium oxidation and organic matter removal efficiency.

A bench-scale pure moving bed bioreactor-membrane bioreactor (MBBR-MBR) used for the treatment of urban wastewater was analyzed for the identification of bacterial strains with the potential capacity for calcium carbonate and struvite biomineral formation. Isolation of mineral-forming strains on calcium carbonate and struvite media revealed six major colonies with a carbonate or struvite precipitation capacity in the biofouling on the membrane surface and showed that heterotrophic bacteria with the ability to precipitate calcium carbonate and struvite constituted ~7.5% of the total platable bacteria. These belonged to the genera Lysinibacillus, Trichococcus, Comamomas and Bacillus. Pyrosequencing analysis of the microbial communities in the suspended cells and membrane biofouling showed a high degree of similarity in all the samples collected with respect to bacterial assemblage. The study of operational taxonomic units (OTUs) identified through pyrosequencing suggested that ~21% of the total bacterial community identified in the biofouling could potentially form calcium carbonate or struvite crystals in the pure MBBR-MBR system used for the treatment of urban wastewater.

The discovering of anaerobic ammonium oxidation (anammox) process led to the development of autotrophic nitrogen removal systems for the treatment of effluents with low C:N rate. The anammox processes provide an efficient way to remove high concentrations of ammonium compounds from industrial and urban wastewater and covert them to dinitrogen. Nevertheless, recently obtained results suggest new ways for research on autotrophic nitrogen removal system including possibility for low temperature operation, adaptation to high organic matter loads and antibiotics inhibition effect. For these reasons, the prevalence and spatial distribution of anammox communities in autotrophic nitrogen removal wastewater treatment technologies, as well as their role in formation of fixed biofilms, are reviewed here in order to illustrate the present and future significance of these microorganisms in environmental biotechnology.

Seven full-scale biological wastewater treatment systems located in the Polar Arctic Circle region in Finland were investigated to determine their Archaea, Bacteria and Fungi community structure, and their relationship with the operational conditions of the bioreactors by the means of quantitative PCR, massive parallel sequencing and multivariate redundancy analysis. The results showed dominance of Archaea and Bacteria members in the bioreactors. The activated sludge systems showed strong selection of Bacteria but not for Archaea and Fungi, as suggested by diversity analyses. Core OTUs in influent and bioreactors were classified as Methanobrevibacter, Methanosarcina, Terrestrial Group Thaumarchaeota and unclassified Euryarchaeota member for Archaea; Trichococcus, Leptotrichiaceae and Comamonadaceae family, and Methylorosula for Bacteria and Trichosporonaceae family for Fungi. All influents shared core OTUs in all domains, but in bioreactors this did not occur for Bacteria. Oligotype structure of core OTUs showed several ubiquitous Fungi oligotypes as dominant in sewage and bioreactors. Multivariate redundancy analyses showed that the majority of core OTUs were related to organic matter and nutrients removal. Also, there was evidence of competition among Archaea and Fungi core OTUs, while all Bacteria OTUs were positively correlated among them. The results obtained highlighted interesting features of extremely cold temperature bioreactors.

Three aerobic granular sequencing batch reactors were inoculated using different inocula from Finland, Spain and a mix of both in order to investigate the effect over the degradation performance and the microbial community structure. The Finnish inoculum achieved a faster granulation and a higher depollution performance within the first two month of operation. However, after 90 days of operation, similar physico-chemical values were observed. On the other hand, the Real-time PCR showed that Archaea diminished from inoculum to granular biomass, while Bacteria and Fungi numbers remained stable. All granular biomass massive parallel sequencing studies were similar regardless of the inocula from which they formed, as confirmed by singular value decomposition principal coordinates analysis, expected effect size of OTUs, and β-diversity analyses. Thermoproteaceae, Meganema and a Trischosporonaceae members were the dominant phylotypes for the three domains studied. The analysis of oligotype distribution demonstrated that a fungal oligotype was ubiquitous. The dominant OTUs of Bacteria were correlated with bioreactors performance. The results obtained determined that the microbial community structure of aerobic granular sludge was similar regardless of their inocula, showing that the granulation of biomass is related to several phylotypes. This will be of future importance for the implementation of aerobic granular sludge to full-scale systems.

Two pilot-scale hybrid moving bed biofilm reactor-membrane bioreactors were operated in parallel for the treatment of salinity-amended urban wastewater under 6 hours of hydraulic retention time and 2500 mg L&minus, 1 total solids concentration. Two salinity conditions were tested: the constant salinity of 6.5 mS cm&minus, 1 electric conductivity (3.6 g L&minus, 1 NaCl) and the tidal-like variable salinity with maximum 6.5 mS cm&minus, 1 electric conductivity. An investigation was developed on the biofouling produced on the ultrafiltration membrane surface evaluating its bacterial community structure and its potential function in the fouling processes. The results showed that biofouling was clearly affected by salinity scenarios in terms of &alpha, diversity and &beta, diversity and bacterial community structure, which confirms lower bacterial diversity under variable salinity conditions with Rhodanobacter and Dyella as dominant phylotypes. Microorganisms identified as bio-mineral formers belonged to genera Bacillus, Citrobacter, and Brevibacterium. These findings will be of help for the prevention and control of biofouling in saline wastewater treatment systems.

The communities of Bacteria, Archaea and Fungi in a full-scale moving bed biofilm reactor in Rukatunturi (Ruka, Finland, in the Polar Arctic Circle) were analyzed in order to observe their ecological role in the operation of this system at low temperature. The bioreactor achieved efficient removal performances organic matter (>96%) and for ammonium (>95%), however a modest removal for total nitrogen (>63–75%). Bacteria dominant phylotypes changed in relation to the different functions: Trichococcus and Polaromonas for denitrification, Trichococcus and Simplicispira for organic matter removal, and Devosia and Thermomonas for nitrification. Bacteria predicted metagenome related to nitrification confirmed ammonium oxidation in nitrification chamber, and reduction of nitrate and nitrite in the denitrification and organic matter removal chambers. Dynamics of Fungi, dominated by Trichosporonaceae and Ascomycota clones, were linked to aeration conditions but not to substrate concentrations. Archaea communities, dominated by Methanobrevibacter genus and Thermoplasmatales-related clones, were not affected by aeration or substrate concentrations. The results obtained offer a valuable insight into the ecological role of microbial communities in full-scale moving bed biofilm reactor operating under extremely low temperatures.

An aerobic granular sludge system has been started-up and operated at 7°C temperature using cold-adapted activated sludge as inoculum. The system could form granular biomass due to batch operation allowing for just 5-3min of biomass sedimentation. Scanning electron microscopy showed that fungi helped in the granular biomass formation in the early stages of the granule formation. The removal performance of the system was of 92-95% in BOD5, 75-80% in COD, 70-76% in total nitrogen and 50-60% in total phosphorous. The bacterial community structure from cold-adapted activated sludge changed during the operational time, leading to a final configuration dominated by Microbacteriaceae members Microbacterium and Leucobacter, which were strongly correlated to biomass settling velocity and bioreactor performance, as suggested by multivariate redundancy analyses. This experiment showed that aerobic granular sludge systems could be successfully started-up and operated, with high performance, under low operational temperatures when using cold-adapted biomass as inoculum.

Full-scale applications of autotrophic nitrogen removal technologies for the treatment of digested sludge liquor have proliferated during the last decade. Among these technologies, the aerobic/anoxic deammonification process (DEMON) is one of the major applied processes. This technology achieves nitrogen removal from wastewater through anammox metabolism inside a single bioreactor due to alternating cycles of aeration. To date, microbial community composition of full-scale DEMON bioreactors have never been reported. In this study, bacterial community structure of a full-scale DEMON bioreactor located at the Apeldoorn wastewater treatment plant was analyzed using pyrosequencing. This technique provided a higher-resolution study of the bacterial assemblage of the system compared to other techniques used in lab-scale DEMON bioreactors. Results showed that the DEMON bioreactor was a complex ecosystem where ammonium oxidizing bacteria, anammox bacteria and many other bacterial phylotypes coexist. The potential ecological role of all phylotypes found was discussed. Thus, metagenomic analysis through pyrosequencing offered new perspectives over the functioning of the DEMON bioreactor by exhaustive identification of microorganisms, which play a key role in the performance of bioreactors. In this way, pyrosequencing has been proven as a helpful tool for the in-depth investigation of the functioning of bioreactors at microbiological scale.