Nitrification performance and microbial community dynamics in a submerged membrane bioreactor with complete sludge retention

A submerged membrane bioreactor (MBR) supplied with inorganic ammonium-bearing wastewater (NH(4)(+)-N, 500 mgl(-1)) was operated for 260 days without sludge purge under decreased hydraulic retention times (HRT) through six steps (from 30 to 5h). Almost complete nitrification was obtained at a volumetric loading rate (VLR)1.2g NH(4)(+)-Nl(-1)day(-1). The sludge nitrification activities were evaluated at each stage. The specific ammonium oxidizing rate (SAOR) decreased from the initial 0.45 to 0.15 kg NH(4)(+)-Nkg(-1)MLSSday(-1) in the last four stages, while the specific nitrate forming rate (SNFR) increased from 0.17 to 0.39 kg NO(3)(-)-Nkg(-1)MLSSday(-1) at the third stage, and then decreased to below 0.1 kg NO(3)(-)-Nkg(-1)MLSSday(-1) from the fourth stage. Microbial population dynamics was investigated by a combination of the MPN method, fluorescence in situ hybridization (FISH) and quinone profiles. During the experiment, although the MLSS increased gradually from 4.5 to 11.5 gl(-1), the number of ammonia-oxidizing bacteria (AOB) decreased from 10(9)l(-1) at the third stage to 10(7)l(-1) in the last two stages, and that of nitrite-oxidizing bacteria (NOB) decreased gradually from 10(8)l(-1) at the second stage (HRT of 20 h) to the final 10(5)l(-1). FISH results showed that the active cells decreased gradually with time from about 60 to 20% in the last two stages, and most of sludge was inert cells. The sum of nitrifiers occupied only about 10% of the total bacteria number in the last stage even though only ammonium-bearing inorganic wastewater was fed in. Nitrosomonas sp. and Nitrospira sp. were confirmed by FISH as the dominant nitrifying genera responsible for ammonia and nitrite oxidation, respectively. In the mean time, a small ratio of Nitrobacter sp. also existed in the system. FISH analysis matched better with the batch activity test results than did the MPN techniques. Quinone profiles revealed that the dominant ubiquinone was ubiquinone-8 (UQ-8), ranging from 84 to 66%, followed by UQ-10 of 7-13%, UQ-7 of 3-5% and UQ-9 of 1.6-2.6%. The dominant menaquinone in the MBR was menaquinone-7 (MK-7) followed by MK-6, MK-8 and MK-8 (H(2)). With the prolongation of operation, the percentage of menaquinones increased from 8 to 14%. The use of the polyphasic approach gave some new insight on variations of microbial community structures.     

Structure and dynamics of microbial community in full-scale activated sludge reactors

Phospholipid fatty acid (PLFA) profiles in four full-scale activated sludge reactors (ASR1 ~ 4) treating municipal wastewater, South Korea, were monitored to evaluate the influence of influent water quality on microbial community structure (MCS) and the effect of the MCS on effluent water quality. In ASR1 ~ 3, PLFA profiles were very similar, regardless of the influent water quality and seasonal differences, and 16:17c/15:0iso2OH and 16:0 were dominant. PLFA profiles in ASR4 during summer and autumn were very similar to those in ASR1 ~ 3, but increases in specific fatty acids, 16:1ω5c, 11methyl18:1ω7c and 15:0iso3OH, were found in ASR4 during winter and spring, with relatively high total suspended solid (TSS) concentrations in the effluent. 16:1ω5c and 15:0iso3OH, possibly related with Flexibacter sp., caused a bulking problem in the activated sludge. The community diversity indices such as Shannon diversity and equability decreased in summer but increased in autumn in all the ASRs. Canonical correspondence analysis results suggested that the influent BOD concentration played the most important role in changing MCS, followed by influent TSS concentration. In addition, the TSS and total phosphorus concentrations in the effluent were significantly affected by the change of the MCS.     

Effects of ferrous iron on the performance and microbial community in aerobic granular sludge in relation to nutrient removal

Lab‐scale experiments were conducted to investigate the effects of ferrous iron on nutrient removal performance and variations in the microbial community inside aerobic granular sludge for 408 days. Two reactors were simultaneously operated, one without added ferrous iron (SBR1), and one with 10 mg Fe²⁺ L^?1 of added ferrous iron (SBR2). A total of 1 mg Fe²⁺ L^?1 of added ferrous iron was applied to SBR1 starting from the 191st day to observe the resulting variations in the nutrient removal performance and the microbial community. The results show that ammonia‐oxidizing bacteria (AOB) could not oxidize ammonia due to a lack of iron compounds, but they could survive in the aerobic granular sludge. Limited ferrous iron addition encouraged nitrification. Enhanced biological phosphorus removal (EBPR) from both reactors could not be maintained regardless of the amount of ferrous iron that was applied. EBPR was established in both reactors when the concentration of mixed liquor suspended solid (MLSS) and the percentage of Accumulibacteria increased. A total of 10 mg Fe²⁺ L^?1 of added ferrous iron had a relatively adverse effect on the growth of AOB species compared to 1 mg Fe²⁺ L^?1 of added ferrous iron, but it encouraged the growth of Nitrospira sp. and Accumulibacteria, which requires further study. It could be said that the compact and stable structure of aerobic granular sludge preserved AOB and NOB from Fe‐deficient conditions, and wash‐out during the disintegration period. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:716–725, 2017     

A metagenome of a full-scale microbial community carrying out enhanced biological phosphorus removal

Enhanced biological phosphorus removal (EBPR) is widely used for removal of phosphorus from wastewater. In this study, a metagenome (18.2 Gb) was generated using Illumina sequencing from a full-scale EBPR plant to study the community structure and genetic potential. Quantitative fluorescence in situ hybridization (qFISH) was applied as an independent method to evaluate the community structure. The results were in qualitative agreement, but a DNA extraction bias against gram positive bacteria using standard extraction protocols was identified, which would not have been identified without the use of qFISH. The genetic potential for community function showed enrichment of genes involved in phosphate metabolism and biofilm formation, reflecting the selective pressure of the EBPR process. Most contigs in the assembled metagenome had low similarity to genes from currently sequenced genomes, underlining the need for more reference genomes of key EBPR species. Only the genome of ‘Candidatus Accumulibacter'', a genus of phosphorus-removing organisms, was closely enough related to the species present in the metagenome to allow for detailed investigations. Accumulibacter accounted for only 4.8% of all bacteria by qFISH, but the depth of sequencing enabled detailed insight into their microdiversity in the full-scale plant. Only 15% of the reads matching Accumulibacter had a high similarity (>95%) to the sequenced Accumulibacter clade IIA strain UW-1 genome, indicating the presence of some microdiversity. The differences in gene complement between the Accumulibacter clades were limited to genes for extracellular polymeric substances and phage-related genes, suggesting a selective pressure from phages on the Accumulibacter diversity.     

Long-term population dynamics and in situ physiology in activated sludge systems with enhanced biological phosphorus removal operated with and without nitrogen removal

Quantitative fluorescence in situ hybridization (FISH) and the combination of FISH with microautoradiography (MAR) were used in order to study the long-term population dynamics (2.5 years) and the in situ physiology in two parallel activated sludge pilot systems with enhanced biological phosphorus removal (EBPR). The two systems received the same influent wastewater, but were differently operated (with and without nitrogen removal, respectively). Both systems showed a significant P removal that increased when different substrates (phosphorus (P), acetate and glucose, respectively) were added to the influent wastewater. Rhodocyclus-related bacteria were present in both systems in significant numbers (ranging from 4 to 28%) throughout the whole period. This supports the hypothesis that these bacteria occur in significant numbers in different types of well-operating EBPR activated sludge processes. However, we observed a lower correlation (< 0.5) for the amount of Rhodocyclus-related bacteria to the P content in activated sludge than previous studies (> 0.9). The Actinobacteria were the only additional group of bacteria which showed a similar degree of correlation to the P content in activated sludge as the Rhodocyclus-related bacteria--but only for the system without nitrogen removal. Significant amounts (< or = 12%) of glycogen-accumulating bacteria (GAOs) were detected in the system with nitrogen removal (but not in the other system), but had no, in contrast to previous observations, apparent negative effect on the overall EBPR performance. FISH-MAR indicated that a significant part of the Betaproteobacteria (part of them identified as Rhodocyclus-related bacteria) as well as the Actinobacteria were able to take up 33Pi, [3H]-acetate and [3H]-glucose under anaerobic-aerobic conditions. The contribution of anoxic 33Pi uptake under alternating anaerobic-anoxic conditions was significantly lower. Interestingly, not all Rhodocyclus-related bacteria showed uptake of these three radioactive substrates. This may be due to differences in metabolic state, physiological potential or genotype, not detectable by the present probe set for Rhodocyclus-related bacteria. Comparison of the 33Pi, [3H]-acetate and [3H]-glucose uptake by activated sludge after different fixation and incubation procedures showed that a part of the observed 33Pi uptake may have been caused by a combination of a biological and chemical or biologically induced chemical P adsorption.     

Microbial population dynamics during sludge granulation in an anaerobic-aerobic biological phosphorus removal system

The evolution of a microbial community was investigated during sludge granulation using a wide range of micro-scale and molecular biology techniques. Experimental results demonstrate that polyphosphate-accumulating granules were successfully cultured during the anaerobic/aerobic cycle. Improvement in sludge sedimentation performance occurred prior to the formation of granular sludge and was not affected by change in granule size. Rod-shaped and filamentous bacteria appeared to initiate granule formation and generate the structures that supported further granule growth. It was observed that mature granules supported microbial populations that differed from nascent granules and were predominantly packed with coccoid bacteria. It was further observed that the diversity of the granular microbial community increased as the granules grew. Accumulibacter, Nitrosospira and Thauera were mainly responsible for nutrient removal while microorganisms such as Rhodocyclus and Hyphomicrobiaceae appeared to be primarily responsible for forming and maintaining the granule structure.     

Metabolic transformations and characterisation of the sludge community in an enhanced biological phosphorus removal system

Enhanced biological phosphorus removal was performed in a continuous laboratory-scale two-reactor system with sludge recirculation over a 75-day period. Influent wastewater was a synthetic medium based on acetate, and the sludge age was kept at 12 days. The adapted sludge stored poly-β-hydroxyalkanoic acids (PHA) in the anaerobic reactor with a conversion ratio of 1.45 PHA/acetic acid (based on chemical O₂ demand: COD/COD) and gave ratio of a phosphate-P release to acetic acid uptake of 0.51 P/CH₃COOH (w/w). Fractionation of anaerobic and aerobic sludges showed that the main part of phosphorus taken up, was eluted in the trichloroacetic acid fraction indicating that it was polyphosphate. A total of 60% of the phosphorus in the aerobic sludge was solubilized in the trichloroacetic acid fraction, whereas this fraction accounted for only 32% of the phosphorus in the anaerobic sludge. Only 4% of the total phosphorus in the aerobic sludge and 2% in the anaerobic sludge was found in the EDTA fraction, indicating low amounts of metal-bound phosphates. Isolation on acetate-based agar medium showed that Acinetobacter strains were present in the sludge. However, a more complete analysis of the bacterial community of the sludge was obtained by creating a clone library based on the 16S rRNA gene. A total of 51 partial clone sequences were phylogenetically evaluated. The predominating group was found in the high-(G+C) (mol%) gram-positive bacterial subphylum (31% of the sequenced clones), while the gamma proteobacteria only constituted 9.8% of the clones. Received: 12 June 1997 / Received revision: 26 September 1997 / Accepted: 28 September 1997     

Systematic analysis of biochemical performance and the microbial community of an activated sludge process using ozone-treated sludge for sludge reduction

Two lab-scale bioreactors (reactors 1 and 2) were employed to examine the changes in biological performance and the microbial community of an activated sludge process fed with ozonated sludge for sludge reduction. During the 122 d operation, the microbial activities and community in the two reactors were evaluated. The results indicated that, when compared with the conventional reactor (reactor 1), the reactor that was fed with the ozonated sludge (reactor 2) showed good removal of COD, TN and cell debris, without formation of any excess sludge. In addition, the protease activity and intracellular ATP concentration of reactor 2 were increased when compared to reactor 1, indicating that reactor 2 had a better ability to digest proteins and cell debris. DGGE analysis revealed that the bacterial communities in the two reactors were different, and that the dissimilarity of the bacterial population was nearly 40%. Reactor 2 also contained more protozoa and metazoa, which could graze on the ozone-treated sludge debris directly.     

Regulation of different electron acceptors on petroleum hydrocarbon biotransformation to final products in activated sludge biosystems

Bioprocess and Biosystems Engineering - The types and concentrations of electron acceptor are the significant factors influencing the oxidation and biotransformation of organic matter in the...     

Comparison of anode bacterial communities and performance in microbial fuel cells with different electron donors

Microbial fuel cells (MFCs) harness the electrochemical activity of certain microbes for the production of electricity from reduced compounds. Characterizations of MFC anode biofilms have collectively shown very diverse microbial communities, raising ecological questions about competition and community succession within these anode-reducing communities. Three sets of triplicate, two-chamber MFCs inoculated with anaerobic sludge and differing in energy sources (acetate, lactate, and glucose) were operated to explore these questions. Based on 16S rDNA-targeted denaturing gradient gel electrophoresis (DGGE), all anode communities contained sequences closely affiliated with Geobacter sulfurreducens (>99% similarity) and an uncultured bacterium clone in the Bacteroidetes class (99% similarity). Various other Geobacter-like sequences were also enriched in most of the anode biofilms. While the anode communities in replicate reactors for each substrate generally converged to a reproducible community, there were some variations in the relative distribution of these putative anode-reducing Geobacter-like strains. Firmicutes were found only in glucose-fed MFCs, presumably serving the roles of converting complex carbon into simple molecules and scavenging oxygen. The maximum current density in these systems was negatively correlated with internal resistance variations among replicate reactors and, likely, was only minimally affected by anode community differences in these two-chamber MFCs with high internal resistance.     

Analysis of the microbial community structure and function of a laboratory scale enhanced biological phosphorus removal reactor

A laboratory scale sequencing batch reactor (SBR) operating for enhanced biological phosphorus removal (EBPR) and fed with a mixture of volatile fatty acids (VFAs) showed stable and efficient EBPR capacity over a four-year-period. Phosphorus (P), poly-beta-hydroxyalkanoate (PHA) and glycogen cycling consistent with classical anaerobic/aerobic EBPR were demonstrated with the order of anaerobic VFA uptake being propionate, acetate then butyrate. The SBR was operated without pH control and 63.67 +/- 13.86 mg P l-1 was released anaerobically. The P% of the sludge fluctuated between 6% and 10% over the operating period (average of 8.04 +/- 1.31%). Four main morphological types of floc-forming bacteria were observed in the sludge during one year of in-tensive microscopic observation. Two of them were mainly responsible for anaerobic/aerobic P and PHA transformations. Fluorescence in situ hybridization (FISH) and post-FISH chemical staining for intracellular polyphosphate and PHA were used to determine that 'Candidatus Accumulibacter phosphatis' was the most abundant polyphosphate accumulating organism (PAO), forming large clusters of coccobacilli (1.0-1.5 micro m) and comprising 53% of the sludge bacteria. Also by these methods, large coccobacillus-shaped gammaproteobacteria (2.5-3.5 micro m) from a recently described novel cluster were glycogen-accumulating organisms (GAOs) comprising 13% of the bacteria. Tetrad-forming organisms (TFOs) consistent with the 'G bacterium' morphotype were alphaproteobacteria, but not Amaricoccus spp., and comprised 25% of all bacteria. According to chemical staining, TFOs were occasionally able to store PHA anaerobically and utilize it aerobically.     

Novel MBR_based main stream biological nutrient removal process: high performance and microbial community

For municipal wastewater treatment, main stream biological nutrient removal (BNR) process is becoming more and more important. This lab-scale study, novel MBR_based BNR processes (named A₂N-MBR and A₂NO-MBR) were built. Comparison of the COD removal, results obtained demonstrated that COD removal efficiencies were almost the same in three processes, with effluent concentration all bellowed 30 mg L^?1. However, the two-sludge systems (A₂N-MBR and A₂NO-MBR) had an obvious advantage over the A²/O for denitrification and phosphorus removal, with the average TP removal rates of 91.20, 98.05% and TN removal rates of 73.00, 79.49%, respectively, higher than that of 86.45 and 61.60% in A²/O process. Illumina Miseq sequencing revealed that Candidatus_Accumulibacter, which is capable of using nitrate as an electron acceptor for phosphorus and nitrogen removal simultaneously, was the dominant phylum in both A₂N-MBR and A₂NO-MBR process, accounting for 28.74 and 23.98%, respectively. Distinguishingly, major organism groups related to nitrogen and phosphorus removal in A²/O system were Anaerolineaceae_uncultured, Saprospiraceae_uncultured and Thauera, with proportions of 11.31, 8.56 and 5.00%, respectively. Hence, the diversity of dominant PAOs group was likely responsible for the difference in nitrogen and phosphorus removal in the three processes.     

Bacterial community dynamics in full-scale activated sludge bioreactors: operational and ecological factors driving community assembly and performance

The assembling of bacterial communities in conventional activated sludge (CAS) bioreactors was thought, until recently, to be chaotic and mostly unpredictable. Studies done over the last decade have shown that specific, and often, predictable random and non-random factors could be responsible for that process. These studies have also motivated a "structure-function" paradigm that is yet to be resolved. Thus, elucidating the factors that affect community assembly in the bioreactors is necessary for predicting fluctuations in community structure and function. For this study activated sludge samples were collected during a one-year period from two geographically distant CAS bioreactors of different size. Combining community fingerprinting analysis and operational parameters data with a robust statistical analysis, we aimed to identify relevant links between system performance and bacterial community diversity and dynamics. In addition to revealing a significant β-diversity between the bioreactors' communities, results showed that the largest bioreactor had a less dynamic but more efficient and diverse bacterial community throughout the study. The statistical analysis also suggests that deterministic factors, as opposed to stochastic factors, may have a bigger impact on the community structure in the largest bioreactor. Furthermore, the community seems to rely mainly on mechanisms of resistance and functional redundancy to maintain functional stability. We suggest that the ecological theories behind the Island Biogeography model and the species-area relationship were appropriate to predict the assembly of bacterial communities in these CAS bioreactors. These results are of great importance for engineers and ecologists as they reveal critical aspects of CAS systems that could be applied towards improving bioreactor design and operation.     

Effect of aspartate and glutamate on the fate of enhanced biological phosphorus removal process and microbial community structure

This study investigated the fate of enhanced biological phosphorus removal (EBPR) and changes in microbial speciation in a sequencing batch reactor (SBR) fed with aspartate and glutamate. It involved SBR operation for 288 days, batch tests for observation of metabolic functions together with microscopic and phylogenetic analyses. Polyphosphate accumulating organisms (PAOs) were observed in abundance with complete removal of phosphorus. Fluorescence in situ hybridization (FISH) combined with 4′,6-dia-midino-2-phenylindole (DAPI) staining confirmed the accumulation of polyphosphate by Rhodocyclus-related and Actinobacterial PAOs. Aspartate seemed to favor the competitive growth of Rhodocyclus-related PAOs since EBPR population used the common biochemical pathways followed by Rhodocyclus-related PAOs in the aspartate fed batch tests. In the glutamate fed batch reactors, however, Actinobacterial PAOs appeared to be competitively selected which explains the lower levels of PHA generation. Even though operational conditions did not change, effective EBPR could not be maintained during the latter part of the study.     

Polyhydroxyalkanoate synthesis using different carbon sources by two enhanced biological phosphorus removal microbial communities

Polyhydroxyalkanoate (PHA) is a biodegradable plastic synthesised by bacteria as energy and carbon storage material. PHA production is mostly based on pure cultures operated under sterile conditions, which increase the costs of this biopolymer. The use of inexpensive mixed culture biomass, such as activated sludge, to produce biodegradable plastics from renewable waste streams has been proposed as an alternative.The effect of carbon sources (acetate, propionate, butyrate and glucose) on the type and quantity of PHA synthesis obtained with different enhanced biological phosphorus removal (EBPR) microbial communities enriched with acetate and propionate are reported in this work. Two sequencing batch reactors (SBRs) were seeded with biomass withdrawn from a non-EBPR wastewater treatment plant (WWTP). The same operational conditions were kept, but using acetate or propionate as the sole carbon source of each reactor. These conditions produced two microbial communities with different P-removal capacity. The results presented in this study show the effect of the carbon source on the PHA composition (amount of polyhydroxybutyrate (PHB), polyhydroxyvalerate (PHV) and polyhydroxy-2-methylvalerate (PH2MV)), which differed not just between substrates but also between the two EBPR communities used. In addition, some monomers not always analysed contribute significantly to the total amount of PHA, especially when using butyrate, showing that if they are not considered this can lead to erroneous calculated yields.     

Sequentially aerated membrane biofilm reactors for autotrophic nitrogen removal: microbial community composition and dynamics

Membrane‐aerated biofilm reactors performing autotrophic nitrogen removal can be successfully applied to treat concentrated nitrogen streams. However, their process performance is seriously hampered by the growth of nitrite oxidizing bacteria (NOB). In this work we document how sequential aeration can bring the rapid and long‐term suppression of NOB and the onset of the activity of anaerobic ammonium oxidizing bacteria (AnAOB). Real‐time quantitative polymerase chain reaction analyses confirmed that such shift in performance was mirrored by a change in population densities, with a very drastic reduction of the NOB Nitrospira and Nitrobacter and a 10‐fold increase in AnAOB numbers. The study of biofilm sections with relevant 16S rRNA fluorescent probes revealed strongly stratified biofilm structures fostering aerobic ammonium oxidizing bacteria (AOB) in biofilm areas close to the membrane surface (rich in oxygen) and AnAOB in regions neighbouring the liquid phase. Both communities were separated by a transition region potentially populated by denitrifying heterotrophic bacteria. AOB and AnAOB bacterial groups were more abundant and diverse than NOB, and dominated by the r‐strategists Nitrosomonas europaea and Ca. Brocadia anammoxidans, respectively. Taken together, the present work presents tools to better engineer, monitor and control the microbial communities that support robust, sustainable and efficient nitrogen removal.     

Selective enrichment of Geobacter sulfurreducens from anaerobic granular sludge with quinones as terminal electron acceptors

A quinone-respiring, enrichment culture derived from methanogenic granular sludge was phylogenetically characterized by using a combined cloning-denaturing gradient gel electrophoresis (DGGE) method, which revealed that the consortium developed was dominated by a single microorganism: 97% related, in a sequence of 1520 base pairs, to Geobacter sulfurreducens. The enrichment culture could grow with acetate, formate or H₂ when humic acids, the humic model compound, anthraquinone-2,6-disulfonate (AQDS), or chelated Fe(III) was provided as a terminal electron acceptor. The occurrence of a humic acid- or quinone-respiring microorganism in the microbial community of a wastewater treatment system suggests that this type of microorganisms may play a potential role in anaerobic bioreactors treating humus-containing wastewaters.     

Changes in respiratory quinone profiles of enhanced biological phosphorus removal activated sludge under different influent phosphorus/carbon ratio conditions

Changes in the microbial community of an enhanced biological phosphorus removal (EBPR) activated sludge system under different influent phosphorus/carbon (P/C) ratio conditions were investigated through evaluation of population respiratory quinone profiles. A total of 13 types of respiratory quinone homologs consisting of 3 types of ubiquinones (UQ) and 10 types of menaquinones (MK) were identified in this study. The dominant quinones were UQ-8 and MK-7 throughout the operational period. A higher P/C ratio (0.1) in the influent stimulated an increase in the mole fractions of UQ-8, MK-7, MK-8(H₄), MK-9(H₄) and MK-8(H₈), suggesting that actinobacterial polyphosphate-accumulating organisms (PAO) containing partially hydrogenated MK, mainly MK-8(H₄), were contributing to EBPR. However, when the P/C ratio gradually decreased from 0.1 to 0.01, the mole fractions of UQ-8 increased from 0.46 to 0.58, while MK-7, MK-8(H₂), MK-8(H₄), MK-9(H₄), MK-8(H₈) and MK-9(H₆) markedly decreased. These changes in the respiratory quinone profiles suggest that glycogen-accumulating organisms corresponding to some Gammaproteobacteria had become dominant populations with a decrease in actinobacterial PAO. On the other hand, increasing abruptly the P/C ratio to 0.1 further caused an increase in the mole fraction of UQ-8, indicating that Rhodocyclus-related organisms were important PAO.     

Contribution of molecular microbiology to the study in water pollution removal of microbial community dynamics

Molecular tools based on 16S rRNA geneidentification are revolutioning microbialecology. After a short presentation of theadvantages and drawbacks of these new tools,the paper gives a succinct review of theirpossibilities as they have been applied to themicrobial ecology of water pollution removal.Examples of applications are presented in thefields of anaerobic digestion, nitrogen andphosphorus removal, filamentous bacteria andbioaugmentation. The data provided give someinsights about microbial diversity, populationdynamics, ecosystems stability and specificmicrobial population activity.