Search

Wastewater treatment and post-treatment drying techniques play a crucial role on the fertilizer value of biosolids. The aim of this study was to investigate: the nitrogen fertilizer value of biosolids from selected biosolid treatment and post treatment dewatering techniques (a) and the effect of drying depth and time on the nitrogen content of biosolid (b). To achieve the first aim, laboratory nitrogen mineralization study was conducted using thermally-hydrolysed-biosolid, activated-biosolid, and anaerobically-digested-biosolids. To achieve the second aim five drying depths were tested (5, 10, 15, 20 and 25 cm). Nitrogen release per tonne biosolid applied was highest for activated (24 kg), and lowest for anaerobically-digested-biosolid (6 kg). Highest total nitrogen was reported for 10 cm drying depth (3.63%) (4 weeks) and lowest for 25 cm (2.64%) (8 weeks). Selection of appropriate biosolid treatment and dewatering technique is key to improve fertilizer value of biosolids.

Activated-sludge is the most widely used biological process to remove pollutants from wastewater worldwide, mainly due to its economic advantages. Bacteria sum up around 95 % of the total microbial community of the activated-sludge, being responsible for most of the water depuration. Filamentous bacteria are normal components of these artificial ecosystems but their excessive growth leads to potential problems, mainly on the sludge settling (filamentous bulking) or on the formation of scums (filamentous foaming), dramatically reducing the efficiency of the wastewater treatment plants (WWTP). Rhodococcus erythropolis is a gram-positive filamentous bacterium previously identified as one of the sources of foams in activated-sludge. The present work aimed at isolating and characterizing phages infecting R. erythropolis, using sewage water and mixed liquor from an urban WWTP as phage source. Two phages were isolated (one from mixed liquor and the other from sewage) and further characterized genetically and biologically. The TEM analysis revealed that both phages belong to the siphovirus morphotype but with different sizes. The one step growth curve, carried at 28 °C in LB medium, revealed that the Rhodococcus phage isolated from mixed liquor and the one isolated from sewage have significant differences with latent periods of 110 min and 35 min, respectively, and burst sizes of 5 PFU/infected and 106 PFU/infected cell, respectively. Both phages were stable between 4 and 28 °C and between pH values from 7 to 10, which suggests good stability in the WWTP environment. Moreover, phages were able to maintain a R. erytropolis suspension at low levels for up to 30 h post-infection, using MOIs of 0.1, 0.5, and 1. Infection with the mixed liquor phage, maintained the bacterial reduction for 48 h in all MOIs tested. These results demonstrate the potential of using phages to control the problem of bacterial foaming in WWTP., info:eu-repo/semantics/publishedVersion

Proteins, an important fraction of the organic matter in wastewater, typically enter a treatment facility as high molecular weight components. These components are degraded by extracellular protein hydrolytic enzymes, denoted as proteases. Adequate protein hydrolysis monitoring is crucial, since protein hydrolysis is often a rate-limiting step in wastewater treatment. However, current monitoring tools lack a high sample throughput and reliable quantification. Here, we present an improved assay for high-throughput protein hydrolysis rate measurements in wastewater treatment applications. A BODIPY FL casein model substrate was implemented in a microplate format for continuous fluorescent quantification. Case studies on a conventional and a high-rate aerobic municipal wastewater treatment plant and a lab-scale, two-stage, anaerobic reactor provided proof-of-concept. The assay presented in this study can help to obtain monitoring-based process insights, which will in turn allow improving biological performance of wastewater treatment installations in the future. KEY POINTS: • Protein hydrolysis is a crucial step in biological wastewater treatment. • Quantification of the protein hydrolysis rate enables in-depth process knowledge. • BODIPY FL casein is a suitable model substrate for a protein hydrolysis assay. • High sample throughput was obtained with fluorescent hydrolysis quantification. Graphical abstract. ispartof: APPLIED MICROBIOLOGY AND BIOTECHNOLOGY vol:104 issue:18 pages:8037-8048 ispartof: location:Germany status: published

Summary Pure (single) cultures of microorganisms and mixed microbial communities (microbiomes) have been important for centuries in providing renewable energy, clean water and food products to human society and will continue to play a crucial role to pursue the Sustainable Development Goals. To use microorganisms effectively, microbial engineered processes require adequate control. Microbial communities are shaped by manageable deterministic processes, but also by stochastic processes, which can promote unforeseeable variations and adaptations. Here, we highlight the impact of stochasticity in single culture and microbiome engineering. First, we discuss the concepts and mechanisms of stochasticity in relation to microbial ecology of single cultures and microbiomes. Second, we discuss the consequences of stochasticity in relation to process performance and human health, which are reflected in key disadvantages and important opportunities. Third, we propose a suitable decision tool to deal with stochasticity in which monitoring of stochasticity and setting the boundaries of stochasticity by regulators are central aspects. Stochasticity may give rise to some risks, such as the presence of pathogens in microbiomes. We argue here that by taking the necessary precautions and through clever monitoring and interpretation, these risks can be mitigated., In this review paper, we highlight the impact of stochasticity in single culture and microbiome engineering. Stochasticity may give rise to some risks, such as the presence of pathogens in microbiomes. We argue here that by taking the necessary precautions and through clever monitoring and interpretation, these risks can be mitigated.

Tese de doutoramento em Chemical and Biological Engineering, O impacto ambiental relacionado com o uso de vários produtos químicos antimicrobianos (biocidas) na prática geral e em ambientes domésticos e industriais está na ordem do dia. A explosão de produtos antimicrobianos para lavagem de mãos e limpeza de superfícies é um bom exemplo da disseminação do uso de biocidas nos últimos anos. Estes têm uma contribuição significativa nos impactos das atividades humanas no meio ambiente e na saúde, principalmente relacionados com a seleção de estirpes resistentes a antibióticos. O processo de lamas ativadas é o tipo de tratamento biológico mais utilizado para remover poluentes de águas residuais em todo o mundo devido às suas vantagens económicas. Diferentes tipos de microrganismos (bactérias, fungos e protozoários) estão envolvidos no processo de depuração das águas residuais. As bactérias correspondem a cerca de 95 % do total da comunidade microbiana presente nas lamas ativadas, sendo as principais responsáveis pela degradação de substâncias orgânicas das águas residuais. As bactérias filamentosas são componentes normais da biomassa das lamas ativadas; no entanto, o seu crescimento excessivo pode causar problemas na sedimentação das lamas (bulking filamentoso) e na formação de espumas (foaming filamentoso) reduzindo a eficiência das estações de tratamento de águas residuais (ETAR). Nesta tese de doutoramento, foi explorada uma nova abordagem para a potencial influência de biocidas sobre o desempenho global de processos de lamas ativadas, abordando-se o uso de biocidas como potenciais compostos de controlo das populações de bactérias filamentosas esclarecendo, simultaneamente, o impacto desses produtos químicos nas comunidades biológicas de uma ETAR. Inicialmente, foi realizado um estudo de 16 ETAR Portuguesas de lamas ativadas, de forma a melhorar o conhecimento dos parâmetros ambientais que determinam a composição e a prevalência da comunidade filamentosa no tanque de arejamento. Um total de 22 morfotipos filamentosos foram identificados. O Tipo 1851 foi o morfotipo mais frequentemente dominante, seguido por Microthrix parvicella e os Tipos 0092 e 0041/0675. Estes também foram os morfotipos dominantes durante as ocorrências de bulking filamentoso. Foram obtidas correlações significativas entre a abundância de bactérias filamentosas e os parâmetros ambientais, mas a análise estatística multivariada apenas confirmou a correlação negativa entre o Tipo 0092 e o Índice Volumétrico de Lamas (IVL), enfatizando a associação deste organismo filamentoso com o bulking. Numa segunda fase, foi avaliado o efeito in-vitro do triclosano [0.25 a 200 μg/mL], do brometo de cetiltrimetilamónio (CTAB) [1 a 40 μg/mL] e do glutaraldeído [40 a 1000 μg/mL] em duas bactérias filamentosas, Nocardia amarae (Gram positiva) e Sphaerotilus natans (Gram negativa). Os resultados mostraram um efeito “dose-dependente” na viabilidade bacteriana e diferentes mecanismos de ação. Além disso, diferenças na suscetibilidade à exposição de cada biocida sugeriram um efeito “estirpe-dependente”. Todos os biocidas causaram fragmentação dos filamentos em células dispersas, perdendo-se também, por isso, a capacidade de produzir flocos. Após a remoção do biocida, as células permaneceram dispersas, e mesmo as bactérias viáveis não foram capazes de produzir novos filamentos em 48 horas. Entre os biocidas testados, o CTAB apresentou o maior efeito biocida, seguido do triclosano e glutaraldeído para N. amarae, mas no caso de S. natans, a ordem entre os dois primeiros inverteu-se, apresentando-se o triclosano como o mais tóxico. Finalmente, foram conduzidos ensaios à escala laboratorial, de forma a avaliar os efeitos biocidas, utilizando amostras de lamas ativadas reais (simulando uma ETAR real), a fim de compreender as mudanças na comunidade microbiana num cenário mais complexo. Os resultados permitiram avaliar o efeito dos biocidas tanto na comunidade microbiana como nos parâmetros de desempenho das unidades de lamas ativadas estudadas. O efeito biocida foi percetível desde o início do ensaio no caso do triclosano (na concentração de 2 mg/g MLSS) e do CTAB e do glutaraldeído (a partir da concentração de 10 mg/g MLSS). As duas bactérias filamentosas dominantes mostraram reações diferentes aos biocidas: a Gram negativa Tipo 0092 demonstrou ser claramente mais resistente do que a Gram positiva Tipo 0041/0675. Conclui-se que a adição de biocidas originou fragmentação de bactérias filamentosas em células dispersas, perda de estrutura dos flocos (menor densidade). Em termos globais, foi demonstrado que é possível aproveitar a presença de biocidas no desempenho global dos processos de lamas ativadas, particularmente no controlo do bulking filamentoso, desde que monitorizados os parâmetros de avaliação do processo, bem como o desempenho geral e estudos iniciais sejam realizados levando em consideração as bactérias filamentosas mais problemáticas., The environmental impact related to the use of antimicrobial chemicals (biocides), in general practice and in domestic and industrial settings, is in the order of the day. The explosion of antimicrobial hand-wash and cleaning products in recent years is a paradigmatic example of the increasing use of biocides. It is well known that their use has a significant contribution to the environmental and health impacts, mainly related with the selection of antibiotic-resistant strains. The activated-sludge process is the most widely used type of biological treatment to remove pollutants worldwide, mainly due to its economic advantages. Different types of microorganisms (bacteria, fungi and protozoa) are involved in the wastewater processing and cleaning. Bacteria sum up around 95 % of the total microbial community of the activated-sludge, being responsible for most of the degradation of organic substances in the wastewater. Filamentous bacteria are normal components of activated-sludge biomass but their excessive growth leads to potential problems mainly on the sludge settling (filamentous bulking) or in the formation of scums (filamentous foaming), thus reducing the efficiency of the wastewater treatment plants (WWTP). In this thesis, a new approach to the potential influence of biocides on the overall performance of activated-sludge processes was explored, addressing the use of biocides as potential control compounds of the filamentous bacteria populations, but also aiming at clarifying the impact of these chemicals in the biological communities of WWTP. At first, a study of 16 Portuguese activated-sludge WWTP was carried out to improve the understanding of the environmental parameters determining the composition and prevalence of the filamentous community in the aeration tank. A total of 22 filamentous morphotypes were identified. Type 1851 was the most frequently dominant morphotype, followed by Microthrix parvicella and Types 0092 and 0041/0675. These were also the dominant morphotypes during bulking occurrences. Significant correlations were obtained between the abundance of filamentous bacteria and environmental parameters, but multivariate statistical analysis only confirmed the negative correlation between Type 0092 and sludge volume index (SVI), emphasizing the association of this particular filamentous organism with bulking. In a second phase, the in-vitro effect of triclosan [0.25 to 200 μg/mL], cetyltrimethyl ammonium bromide (CTAB) [1 to 40 μg/mL] and glutaraldehyde [40 to 1000 μg/mL] on two filamentous bacteria, Nocardia amarae (Gram positive) and Sphaerotilus natans (Gram negative), was assessed. The results showed a dose-dependent effect on bacterial viability and different action mechanisms. Moreover, differences in susceptibility to exposure of each biocide suggested a strain-dependent effect. All biocides led to morphological modification of the filaments leading to their fragmentation to single cells. Therefore, the ability to enhance floc formation through the filament skeleton was also lost. After biocide removal, the morphology remained as single cells, even in viable bacteria, which were not able to produce new filaments in the next 48 h. Among the biocides tested, CTAB was found to present the highest biocidal effect, followed by triclosan and glutaraldehyde for N. amarae, whereas for S. natans, the ranking of toxicity was triclosan, CTAB and glutaraldehyde. Finally, bench-scale assays were conducted to evaluate biocide global effects using samples of real activated-sludge (mimicking a real WWTP). Simultaneously the performance of the plants was assessed. The results allowed to infer the effect of biocides both in the microbial community and in the performance of activated-sludge units. The biocidal effect was perceptible since the very beginning of the assay for triclosan at the lowest concentration (2 mg/g MLSS), but for CTAB and glutaraldehyde, the effect was only noticeable at the concentration of 10 mg/g MLSS. The two dominant filamentous bacteria, Type 0092 and 0041/0675, showed different susceptibility to the biocides and, in this case, the Gram negative Type 0092 was clearly more resistant then the Gram positive Type 0041/0675. It was also possible to infer that the biocides addition gave rise to fragmentation of filamentous bacteria into single cells and loss of floc structure (lower density). In global terms, it has been shown that it is possible to take advantage of the presence of these biocides in the overall performance of activated-sludge processes, particularly in the filamentous bulking control, as long as the other components and overall performance are monitored and initial studies are accomplished taking in consideration the problematic filamentous bacteria., The work presented in this thesis was performed in the Centre of Biological Engineering (CEB), Minho University. Financial support was provided by the Portuguese Foundation for Science and Technology (FCT) and European Social Fund (POPH-QREN) through a research grant (SFRH/BD/80054/2011), by national funds through FCT under the scope of the strategic funding of UIDB/04469/2020 unit and BioTecNorte operation (NORTE-01-0145- FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte; and by the FEDER funds through the project PTDC/AAG-TEC/3331/2014, financed under the Operational Competitiveness Programme (COMPETE), and by national funds through FCT. Also, the author gratefully acknowledges AGERE-E.M.

The main purposes of this research work were to realize the potential of sludge valorization by converting the sludge into adsorbents and to investigate the performance of sludge-based adsorbents for rare earth elements (REEs) recovery from dilute aqueous solutions. Hydrochloric acid and Fenton reagents were employed as pretreatment procedures to enhance the surface area and adsorption yield. Following this, sludge-based alginate beads were prepared by using HCl treated (HT) and Fenton treated (FT) sludge materials. The chemical composition and surface chemistry of sludge-based adsorbent beads were thoroughly analyzed by state-of-the-art analytical techniques, such as Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and Brunauer-Emmett-Teller (BET) analysis. The prepared beads were then investigated for the recovery of REEs. The batch adsorption studies revealed that the FT sludge beads performed better in comparison to the HT sludge beads. Among REEs, the HT- and FT-sludge beads demonstrated higher affinity towards Sm3+ ions, displaying the maximum adsorption capacities of 2.83 mg/g and 4.16 mg/g, respectively, in a multi-component system (C o = 25 ppm of each REE; pH = 5, t = 24 h and dosage = 5 g/L). In conclusion, the results from this work showed that the prepared sludge-based alginate beads can be used for REEs recovery from diluted waste streams and the tested sludge treatment options were also found effective in converting the waste to resource i.e., sludge to adsorbent for REEs recovery.

The rapid spread of antibiotic resistance challenges modern medicine. So far, mechanistic and quantitative knowledge concerning the spread of resistance genes mainly relies on laboratory experiments with simplified setups, e.g. two strain communities. Thus, the transferability of the obtained process rates might be limited. To investigate the role of a diverse community concerning the dissemination of the multidrug resistance plasmid RP4, an Escherichia coli harboring RP4 invaded a microbial community consisting of 21 species. Changes in the community composition as well as plasmid uptake by community members were monitored for 22 days. Special focus was laid on the question of whether the observed changes were dependent on the actual invading donor isolate and the ambient antibiotic concentration. In our microcosm experiment, the community composition was primarily influenced by the given environmental variables and only secondarily by the particular invader E. coli. The establishment of resistance within the community, however, was directly dependent on the donor identity. The extent to which ambient conditions influence the spread of RP4 depended on the E. coli donor strain. These results emphasize that even within one species there are great differences in the ability to conquer an ecological niche and to spread antibiotic resistance.

Enhanced biological phosphorus removal (EBPR) is an efficient and sustainable technology to remove phosphorus from wastewater. A widely known cause of EBPR deterioration in wastewater treatment plants (WWTPs) is the presence of nitrate/nitrite or oxygen in the anaerobic reactor. Moreover, most existing studies on the effect of either permanent aerobic conditions or inhibition of EBPR by nitrate or free nitrous acid (FNA) have been conducted with a Candidatus Accumulibacter or Tetrasphaera-enriched sludge, which are the two major reported groups of polyphosphate accumulating organisms (PAO) with key roles in full-scale EBPR WWTPs. This work reports the denitrification capabilities of a bio-P microbial community developed using glutamate as the sole source of carbon and nitrogen. This bio-P sludge exhibited a high denitrifying PAO (DPAO) activity, in fact, 56% of the phosphorus was uptaken under anoxic conditions. Furthermore, this mixed culture was able to use nitrite and nitrate as electron acceptor for P-uptake, being 1.8 mu g HNO2-N.L- 1 the maximum FNA concentration at which P-uptake can occur. Net P-removal was observed under permanent aerobic conditions. However, this microbial culture was more sensitive to FNA and permanent aerobic conditions compared to Ca. Accumulibacter-enriched sludge. Spanish Ministerio de Economia y CompetitividadSpanish Government [CTQ2014-60495-R, CTQ2017-82404-R]; Fondo Europeo de Desarrollo Regional (FEDER)European CommissionSpanish Government; Universitat Autonoma de Barcelona; GENOCOV research group (Grup de Recerca Consolidat de la Generalitat de Catalunya)Generalitat de Catalunya [2017SGR 1175] This work was supported by the Spanish Ministerio de Economia y Competitividad (CTQ2014-60495-R and CTQ2017-82404-R) with funds from the Fondo Europeo de Desarrollo Regional (FEDER). Natalia Rey is grateful for the PIF PhD grant funded by the Universitat Aut`onoma de Barcelona. The authors are members of the GENOCOV research group (Grup de Recerca Consolidat de la Generalitat de Catalunya, 2017SGR 1175, www.genocov.com).

Aerobic granular sludge (AGS) is a promising alternative wastewater treatment to the conventional activated sludge system allowing space and energy saving. Basic understanding of AGS has mainly been obtained using simple wastewater containing acetate and propionate as carbon source. Yet, the aspect and performances of AGS grown in such model systems are different from those obtained in reactor treating real wastewater. The impact of fermentable and hydrolyzable compounds on already formed AGS was assessed separately by changing the composition of the influent from simple wastewater containing volatile fatty acids to complex monomeric wastewater containing amino acids and glucose, and then to complex polymeric wastewater containing also starch and peptone. The reversibility of the observed changes was assessed by changing the composition of the wastewater from complex monomeric back to simple. The introduction of fermentable compounds in the influent left the settling properties and nutrient removal performance unchanged, but had a significant impact on the bacterial community. The proportion of Gammaproteobacteria diminished to the benefit of Actinobacteria and the Saccharibateria phylum. On the other hand, the introduction of polymeric compounds altered the settling properties and denitrification efficiency, but induced smaller changes in the bacterial community. The changes induced by the wastewater transition were only partly reversed. Seven distinct stables states of the bacterial community were detected during the 921 days of experiment, four of them observed with the complex monomeric wastewater. The transitions between these states were not only caused by wastewater changes but also by operation failures and other incidences. However, the nutrient removal performance and settling properties of the AGS were globally maintained due to the functional redundancy of its bacterial community.

Application of nanomaterials for the treatment of effluents originated from various industrial and non-industrial sources, has been rapidly developed in recent decades. In this situation, there is a need for conclusive studies to identify the current status of the knowledge in this field and to promote the commercialization of such technologies by providing recommendations for future studies. In the present manuscript, a scientometric assessment on the progress made in this field has been performed and the results have been organized and discussed in terms of science statistics, research hotspots and trends, as well as the relevant sustainability aspects. Based on a set of keywords, identified through a pre-literature analysis, a total of 6539 documents were retrieved from the Web of Science (WoS) database and analyzed to achieve the main goals of this study. The results demonstrate that the studies in this field have been initiated since the beginning of the 2000s but were mainly performed in lab and pilot scales. Also, China and Iran were identified as the most contributing countries in this scientific area in terms of the number of publications. Among various types of engineered nanomaterials (ENMs), there has been especial attention for the application of iron-based nanomaterials as well as carbonaceous structures (such as graphene oxide and biochar). Besides, there are not still strong collaborations formed among researchers in this area worldwide. Regarding the research hotspots, the synthesis of green and sustainable nanomaterials (e.g., biosynthesis approaches) has received attention in recent years. The results can also demonstrate that the most widely studied pathway for the removal of pollutants from (waste)waters involves the adsorption of the pollutants using ENMs. Treatment of contaminants of emerging concern (CECs) as well as exploring the mechanisms involved in the treatment of contaminated (waste)waters using ENMs and the possible by-products are considered the current trends in the literature. Regarding the sustainability aspects of ENMs for (waste)water treatment, the results achieved in this study calls for in-depth sustainability studies, which consider parameters such as economic, environmental, and social aspects of nanomaterials utilization for (waste)water treatment purposes, besides the technical parameters, to push transferring such technologies from lab and pilot scales to large and real-scale applications. ispartof: NANOIMPACT vol:22 ispartof: location:Netherlands status: published

Despite recent evidence from full-scale plants suggesting that Candidatus Accumulibacter may be capable of using amino acids, this metabolic trait has never been confirmed in a bioreactor experiment. Here we show that an enriched culture of Ca. Accumulibacter clade IIF strain SCELSE-1 could metabolize 11 of 20 α-amino acids, with aspartate, glutamate, asparagine, and glutamine resulting in the highest phosphorus removal. The anaerobic uptake of aspartate and glutamate was achieved through a glutamate/aspartate-proton symporter fully powered by the proton motive force (PMF). Under anaerobic conditions aspartate was deaminized and routed into core carbon metabolic pathways to form polyhydroxyalkanoates (PHA). The lack of genes encoding NADH dependent isocitrate dehydrogenase in the Ca. Accumulibacter genome resulted in a kinetic barrier for glutamate to be channelled to the TCA cycle. Glutamate was stored as glutamate polymer. When amino acids (aspartate or glutamate) and acetate were supplied together, Ca. Accumulibacter took up both carbon sources simultaneously, with the uptake rate of each carbon source largely preserved. Overall energy savings (up to 17%) were achieved under mixed carbon scenarios, due to the ability of Ca. Accumulibacter to rearrange its anaerobic carbon metabolism based on the reducing power, PMF and ATP balance. Ministry of Education (MOE) National Research Foundation (NRF) This research was supported by the Singapore National Research Foundation and the Ministry of Education under the Research Centre of Excellence Programme, and by a research grant from the National Research Foundation under its Environment and Water Industry Programme (project number 1102−IRIS−10−02), administered by Public Utilities Board, Singapore’s national water agency. Dr. Guanglei Qiu acknowledges the support of National Natural Science Foundation of China (No. 51808297) and the Fundamental Research Funds for the Central Universities, China (No. 2019ZD21).

The efficiency of microbial interspecies electron transfer between syntrophic bacteria and methanogens is considered a rate-limiting factor for the overall efficiency of anaerobic digestion (AD). Stimulating interspecies electron transfer by biochars has been demonstrated to be efficient to enhance AD. However, the enhancing effects vary significantly depending on biochar properties. The correlations between them are not fully under-stood. Herein, biochars with different physicochemical properties were produced from a whiskey by-product "draff" and subsequently applied in the digestion of draff. The biochar produced at 700 degrees C statistically (p less than 0.05) enhanced biomethane yield by 5%. In contrast, biochars produced at 500 and 900 degrees C did not increase biomethane yield. The addition of 700 degrees C-derived biochar in AD increased the relative abundance of the methanogen Methanosarcina, which may be the electron-accepting partner in direct interspecies electron transfer (DIET). The enrichment of Methanosarcina suggested the potential shift of the interspecies electron transfer pathway towards the DIET mode. The characterization of biochar properties suggested that moderate graphiti-zation degree and abundant active surface functional groups (such as -C = O, pyridinic-N, and graphitic-N) were correlated with a more stimulating interspecies electron transfer through both the carbon matrices and the charging - discharging cycles of surface functional groups.

Sewage sludge biodrying is a treatment that uses bio-heat generated from organic degradation to remove water from sewage sludge. Dewatering is still limited during biodrying, due to the presence of extracellular polymeric substances (EPS) in sludge. To study the biodrying mechanism associated with EPS compositions tryptophan and tyrosine degradations, this study investigated the microbial function in sludge biodrying material. This study conducted a taxonomic analysis of biodrying material; determined the most abundant genetic functions; analyzed the functional microorganisms involved in the degradations of tryptophan and tyrosine; and summarized the metabolic pathways. The results indicated efficient degradations of tryptophan and tyrosine were observed during the initial thermophilic phase; functional microorganisms were mainly from the phyla Firmicutes, Actinobacteria, and Proteobacteria, enriched with genes involved in amino acid transport and metabolism. These findings highlight the potentially important microorganisms and typical pathways that may help improve de-waterability during biodegradation.

Basic understanding of formation of aerobic granular sludge (AGS) has mainly been derived from lab-scale systems with simple influents containing only highly diffusible volatile fatty acids (VFA) as organic substrate. This study compares start-up of AGS systems fed by different synthetic and municipal wastewaters (WW), characterised by increasing complexity in terms of non-diffusible organic substrate. Four AGS reactors were started with the same inoculum activated sludge and operated for one year. The development of AGS, settling characteristics, nutrient and substrate removal performance as well as microbial community composition were monitored. Our results indicate that the higher the content of diffusible organic substrate in the WW, the faster the formation of AGS. The presence of non-diffusible organic substrate in the influent WW led to the formation of small granules and to the presence of 20–40% (% of total suspended solids) of flocs in the AGS. When AGS was fed with complex influent WW, the classical phosphorus and glycogen accumulating organisms (PAO, GAO) were outcompeted by their fermentative equivalents. Substrate and nutrient removal was observed in all reactors, despite the difference in physical and settling properties of the AGS, but the levels of P and N removal depended on the influent carbon composition. Mechanistically, our results indicate that increased levels of non-diffusible organic substrate in the influent lower the potential for microbial growth deep inside the granules. Additionally, non-diffusible organic substrates give a competitive advantage to the main opponents of AGS formation – ordinary heterotrophic organisms (OHO). Both of these mechanisms are suspected to limit AGS formation. The presented study has relevant implications for both practice and research. Start-up duration of AGS systems treating high complexity WW were one order of magnitude higher than a typical lab-scale system treating VFA-rich synthetic WW, and biomass as flocs persisted as a significant fraction. Finally, the complex synthetic influent WW – composed of VFA, soluble fermentable and particulate substrate - tested here seems to be a more adequate surrogate of real municipal WW for laboratory studies than 100%-VFA WW., Graphical abstract Image 1, Highlights • Formation of aerobic granules with synthetic and real wastewaters was compared. • Slower granulation with wastewaters containing high non-diffusible substrate. • Larger floc fractions in biomass with non-diffusible substrate in influent. • Similar microbial communities with different AGS characteristics. • Complex synthetic wastewater can be a good surrogate for real wastewater.

Laboratory-scale experiments were conducted to investigate the (bio)transformation of the antidiabetic sitagliptin (STG) and the antihistamine fexofenadine (FXF) during wastewater treatment. As inoculum either attached-growth on carriers or suspended sludge from a hybrid moving bed biofilm reactor (HMBBR) was used. Both target compounds were incubated in degradation experiments and quantified via LC-MS/MS for degradation kinetics. Furthermore transformation products (TPs) were analyzed via high resolution mass spectrometry (HRMS). Structural elucidation of the TPs was based on the high resolution molecular ion mass to propose a molecular formula and on MS2 fragmentation to elucidate the chemical structure of the TPs. In total, 22 TPs (9 TPs for STG and 13 TPs for FXF) were detected in the experiments with STG and FXF. For all TPs, chemical structures could be proposed. STG was mainly transformed via amide hydrolysis and conjugation of the primary amine moiety. In contrast, FXF was predominantly transformed by oxidative reactions such as oxidation (dehydrogenation) and hydroxylation. Furthermore, FXF was removed significantly faster in contact with carriers compared to suspended sludge, whereas STG was degraded slightly faster in contact with suspended sludge. Moreover, the primary TP of FXF was also degraded faster in contact with carriers leading to higher proportions of secondary TPs. Thus, the microbial community of both carriers and suspended sludge catalyzed the same primary transformation reactions but the transformation kinetics of FXF and the formation/degradation of FXF TPs were considerably higher in contact with carrier-attached biomass. The primary degradation of both target compounds in pilot- and full-scale conventional activated sludge (CAS) and MBBR reactors reached 42 and 61% for FXF and STG, respectively. Up to three of the identified TPs of FXF and 8 TPs of STG were detected in the effluents of pilot- and full-scale CAS and MBBR.

In this work we report the complete sequence and assembly of the estradiol-degrading bacterium Novosphingobium tardaugens NBRC 16725 genome into a single contig using the Pacific Biosciences RS II system., We acknowledge the financial support provided by the Ramón Areces Foundation.

WOS: 000502747400002, In this study, a high sensitive metamaterial sensor has been designed to detect quality of water for water treatment centre. The water samples have been obtained and electrical properties have been measured in microwave range to design the proposed sensor. These electrical properties have been assigned in microwave simulator. Water quality has been investigated by using parametric study and genetic algorithm approach to realize high sensitivity in terms of resonance frequency shift. Around 130 MHz frequency shift has been observed between the water samples. This shift is sufficient to detect instantaneously to the quality of water. This is the first study that metamaterial approach has been used to detect water quality in literature., Scientific and Technological Research Council of TurkeyTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [117M855], The authors received financial support from the Scientific and Technological Research Council of Turkey (117M855).

The objective of this study was to study the occurrence, fate, and seasonal variations of pharmaceuticals at two urban wastewater treatment plants (WWTPs) in India and compare the results with a similar study conducted in the United States. This is the first study of its kind in comparing occurrence and fate of pharmaceuticals in wastewater of two different countries with the same methodology and analytical techniques. Twelve most relevant pharmaceuticals were selected for seasonal monitoring at two Indian WWTPs based on the comprehensive survey and through literature review. The yearly average influent concentrations of total pharmaceuticals were found to be 537 +/- 5 mu g/L at WWTP-1 and 353 +/- 9 mu g/L at WWTP-2. WWTP-2 exhibited comparatively higher removal efficiency of total pharmaceuticals (85% versus 59%, excluding monsoon season), possibly due to the cyclic activated sludge technology followed by chlorination employed at WWTP-2. Comparison with a similar study conducted in the United States revealed that concentration of most of the pharmaceuticals detected in the U.S. WWTPs were, on an average, more than 50% lower. U.S. WWTPs also exhibited 10-30% higher removal efficiencies for total pharmaceuticals. Our study results show that preliminary treatment and biological treatment alone are not adequate for complete removal of pharmaceuticals and polishing step and tertiary treatment is a necessity if higher removal of pharmaceuticals is desired in Indian WWTPs. Information obtained from this study will not only aid the local utilities but will also benefit understanding of global trends in usage of pharmaceuticals and their distribution in the environment. (C) 2016 Elsevier Ltd. All rights reserved.

While deammonification of high-strength wastewater in the sludge line of sewage treatment plants has become well established, the potential cost savings spur the development of this technology for mainstream applications. This study aimed at identifying the effect of aeration and organic carbon on the deammonification process. Two 10 L sequencing bath reactors with different aeration frequencies were operated at 25 degrees C. Real wastewater effluents from chemically enhanced primary treatment and high-rate activated sludge process were fed into the reactors with biodegradable chemical oxygen demand/nitrogen (bCOD/N) of 2.0 and 0.6, respectively. It was found that shorter aerobic solids retention time (SRT) and higher aeration frequency gave more advantages for aerobic ammonium-oxidizing bacteria (AerAOB) than nitrite oxidizing bacteria (NOB) in the system. From the kinetics study, it is shown that the affinity for oxygen is higher for NOB than for AerAOB, and higher dissolved oxygen set-point could decrease the affinity of both AerAOB and NOB communities. After 514 days of operation, it was concluded that lower organic carbon levels enhanced the activity of anoxic ammonium-oxidizing bacteria (AnAOB) over denitrifiers. As a result, the contribution of AnAOB to nitrogen removal increased from 40 to 70%. Overall, a reasonably good total removal efficiency of 66% was reached under a low bCOD/N ratio of 2.0 after adaptation.

Exposure to endocrine-disrupting chemicals (EDCs), such as estrogens, is a growing issue for human and animal health as they have been shown to cause reproductive and developmental abnormalities in wildlife and plants and have been linked to male infertility disorders in humans. Intensive farming and weather events, such as storms, flash flooding, and landslides, contribute estrogen to waterways used to supply drinking water. This paper explores the impact of estrogen exposure on the performance of slow sand filters (SSFs) used for water treatment. The feasibility and efficacy of SSF bioaugmentation with estrogen-degrading bacteria was also investigated, to determine whether removal of natural estrogens (estrone, estradiol, and estriol) and overall SSF performance for drinking water treatment could be improved. Strains for SSF augmentation were isolated from full-scale, municipal SSFs so as to optimize survival in the laboratory-scale SSFs used. Concentrations of the natural estrogens, determined by gas chromatography coupled with mass spectrometry (GC-MS), revealed augmented SSFs reduced the overall estrogenic potency of the supplied water by 25% on average and removed significantly more estrone and estradiol than nonaugmented filters. A negative correlation was found between coliform removal and estrogen concentration in nonaugmented filters. This was due to the toxic inhibition of protozoa, indicating that high estrogen concentrations can have functional implications for SSFs (such as impairing coliform removal). Consequently, we suggest that high estrogen concentrations could impact significantly on water quality production and, in particular, on pathogen removal in biological water filters.

'Sludge-drying lagoons' are a preferred sludge treatment and drying method in tropical and subtropical areas due to the low construction and operational costs. However, this method may be a potential significant source of methane (CH4) because some of the organic matter would be microbially metabolized under anaerobic conditions in the lagoon. The quantification of CH4 emissions from lagoons is difficult due to the expected temporal and spatial variations over a lagoon maturing cycle of several years. Sporadic ebullition of CH4, which cannot be easily quantified by conventional methods such as floating hoods, is also expected. In this study, a novel method based on mass balances was developed to estimate the CH4 emissions and was applied to a full-scale sludge-drying lagoon over a three year operational cycle. The results revealed that processes in a sludge-drying lagoon would emit 6.5 kg CO2-e per megaliter of treated sewage. This would represent a quarter to two-thirds of the overall greenhouse gas (GHG) emissions from wastewater-treatment plants (WWTPs). This work highlights the fact that sludge-drying lagoons are a significant source of CH4 that adds substantially to the overall GHG footprint of WWTPs despite being recognized as a cheap and energy-efficient means of drying sludge. Refereed/Peer-reviewed

This study investigates the microbial community composition, in the biofilms grown on two different support media in fixed biofilm reactors for aerobic wastewater treatment, using next generation sequencing (NGS) technology., This study investigates the microbial community composition in the biofilms grown on two different support media in fixed biofilm reactors for aerobic wastewater treatment, using next generation sequencing (NGS) technology. The chemical composition of the new type of support medium (TDR) was found to be quite different from the conventionally used support medium (stone). The analysis of 16S rRNA gene fragments recovered from the laboratory scale biofilm system show that biofilm support media and temperature conditions influence bacterial community structure and composition. Greater bacterial diversity was observed under each condition, primarily due to the large number of sequences available and sustenance of rare species. There were 6 phyla found, with the highest relative abundance shown by the phylum Proteobacteria (52.71%) followed by Bacteroidetes (33.33%), Actinobacteria (4.65%), Firmicutes, Verrucomicrobia (3.1%) and Chloroflex (>1%). The dataset showed 17 genera of bacterial populations to be commonly shared under all conditions, suggesting the presence of a core microbial community in the biofilms for wastewater treatment. However, some genera in the biofilms on TDR were observed in high proportions, which may be attributed to its chemical composition, explaining the improved level of wastewater treatment. The findings show that the structure of microbial communities in biofilm systems for wastewater treatment is affected by the properties of support matrix.

Achievement of good effluent quality is always the main goal for wastewater treatment plant (WWTP) systems. However, these WWTPs have developed further objectives that include efficient design and strategic control options, with the prospect of their conversion into waste resource recovery facilities (WRRFs) that operate on reduced energy costs. With all these aspects becoming an intrinsic part of waste treatment, mathematical models that simulate WWTP unit processes are becoming of increasing relevance for the achievement of WRRF goals (including good effluent quality, low energy costs and nutrient recovery). It is expected that these mathematical models will benefit potential future applications of automation process control, which have also been developing rapidly with the availability of more reliable and affordable sensors. However, simulated automation control strategies require a thorough evaluation protocol to ensure their viability prior to being adopted as efficient operation control measures. This study considers the comparison of different control strategies implemented on a standard WWTP layout, for plant optimization. The initial task was to define performance indices, effluent quality index (EQI) and operation cost index (OCI), based on a previous investigation by the International Water Association (IWA) benchmark simulation modelling (BSM) task group. These performance indices were then used to evaluate the following strategies: (i) adding a fermentation tank, (ii) dosing flocculant and (iii) implementing a balancing tank. A control strategy was only assumed to be effective with improvement or maintenance of effluent quality. Overall, the evaluation exercise proved to be useful for providing expert advice on efficiency of proposed waste treatment system layouts, towards determination of the best configuration of future WRRFs. For instance, it was notable that significant organic strength is needed for removal of nutrients recycled back from the anaerobic digestion (AD) system into the activated sludge (AS) – hence alternate methods to put the nutrient-rich outflow from the AD system to good use are required. Keywords: WWTP control strategy, activated sludge, performance index, plant wide modelling

Intensive livestock farming cannot be uncoupled from the massive production of manure, requiring adequate management to avoid environmental damage. The high carbon, nitrogen and phosphorus content of pig manure enables targeted resource recovery. Here, fifteen integrated scenarios for recovery of water, nutrients and energy are compared in terms of technical feasibility and economic viability. The recovery of refined nutrients with a higher market value and quality, i.e., (NH4)2SO4 for N and struvite for P, coincided with higher net costs, compared to basic composting. The inclusion of anaerobic digestion promoted nutrient recovery efficiency, and enabled energy recovery through electricity production. Co-digestion of the manure with carbon-rich waste streams increased electricity production, but did not result in lower process costs. Overall, key drivers for the selection of the optimal manure treatment scenario will include the market demand for more refined (vs. separated or concentrated) products, and the need for renewable electricity production. ispartof: BIORESOURCE TECHNOLOGY vol:272 pages:582-593 ispartof: location:England status: published

Emerging global threats, such as climate change, urbanization and water depletion, are driving forces for finding a feasible substitute for low cost-effective conventional activated sludge (AS) technology. On the other hand, given their low cost and easy operation, nature-based systems such as constructed wetlands (CWs) and waste stabilization ponds (WSPs) appear to be viable options. To examine these systems, a 210-day experiment with 31 days of peak load scenario was performed. Particularly, we conducted a deliberate strategy of experimentation, which includes applying a preliminary study, preliminary models, hypothetical tests and power analysis to compare their removal efficiencies and resilience capacities. In contrast to comparable high removal efficiencies of organic matter—around 90%—both natural systems showed moderate nutrient removal efficiencies, which inferred the necessity for further treatment to ensure their compliance with environmental standards. During the peak period, the pond treatment systems appeared to be the most robust as they indicated a higher strength to withstanding the organic matter and nitrogen shock load and were able to recover within a short period. However, high demand of land—2.5 times larger than that of AS—is a major concern of the applicability of WSPs despite their lower operation and maintenance (O&M) costs. It is also worth noting that initial efforts on systematic experimentation appeared to have an essential impact on ensuring statistically and practically meaningful results in this comparison study.

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.

International audience; A lab-scale membrane bioreactor was fed with fresh urine collected from source separation public toilets to perform full nitrification, urinary nitrogen stabilization and effluent sanitation. After acclimation, a nitrogen loading rate (NLR) of 1.2 kg TN per m(3) d(-1) was reached with an average nitrification rate of 98.3%. Dissolved organic matter (DOM) transformation was studied within the MBR to identify biomass activity indicators that could be used for process optimization. By combining three-dimensional excitation emission fluorescence (3DEEM) and liquid chromatography coupled with organic carbon detection, nitrogen detection and UV detection (LC-OCD-OND-UVD), it was possible to investigate the transformation and fate of urine DOM during biological reactions and membrane separation. Results show that urine is mainly composed of low molecular weight molecules (

Ciprofloxacin (CPX), a fluoroquinolone antibiotic, is found in the bulk effluents emerged from pharmaceutical industries. Its presence in the effluent may lead to toxicity to the aquatic life and antimicrobial resistance. Hence, the oxidative degradation of CPX by classical Fenton's process was investigated for the present study. The maximum CPX and total organic carbon (TOC) removal from the synthetic wastewater (initial CPX concentration = 100 mg L-1) were 70% and 55%, respectively, under the best reaction conditions ([H2O2]:[Fe2+] = 10, stoichiometric H2O2 concentration = 14.2 mM and initial wastewater pH = 3.0). Five major degradation products could be identified by high resolution liquid chromatography mass spectrometry (HR LC-MS) which could have resulted by the occurrence of decarboxylation, defluorination, hydroxylation and cleavage of the piperazine ring. The time based detection of ferrous and ferric ions in aqueous phase confirmed the CPX degradation by hydroxyl radicals. A pathway has been proposed for CPX degradation by Fenton's process based on the kinetic decay and/or evolution profiles of CPX and intermediates as well as the release of inorganic ions into the aqueous solution. It was indicated from the rapid respirometric test that the wastewater toxicity was lowered after Fenton's treatment. (C) 2017 Elsevier Ltd. All rights reserved.

The effect of a high and low non-starch polysaccharide diet (HNSP and LNSP diet) and ultrasound treatment on particle size distribution and carbon bioavailability in fecal waste of rainbow trout (Oncorynchus mykiss) was studied. Feces were collected from four flow-through fish tanks, two tanks fed the HNSP diet and two the LNSP diet. The collected feces were sonicated (disintegrated) in duplicate with high-intensity (0.6 W/ml), low-frequency (f = 20 Hz) ultrasound at five different energy levels (0.6 W/ml for 0, 0.25, 1, 4, and 16 min). The particle size distribution of the treated feces samples was measured by wet sieving (1000, 500, 200, 100, 63, 36, 1.2 μm screen size) and total suspended solids (TSS) measurement. Carbon bioavailability in sonicated fecal waste samples was determined with oxygen uptake rate (OUR) tests. The results showed that: (1) feces from the HNSP diet contained significant more particulate material and bigger particles; (2) carbon bioavailability was almost three times higher in untreated LNSP feces when compared with HNSP feces; (3) almost 50% of HNSP feces could have been recovered on a microscreen of 36 μm after wet sieving, whereas it was only 10% for LNSP feces; (4) the production of small particles (1.2–36 μm), which could pass a drum filter screen and potentially accumulate in RAS, was approximately 50 g/kg feed, showing no significant differences between diets; (5) sonication increased fecal dry matter below 36 μm (p = 0.015), but it had no significant effect on the median particle size; (6) sonication increased carbon bioavailability with 7–10% for the HNSP feces (p = 0.037); (7) fecal particles withstood up to 16 min sonication at an intensity of 0.6 W/ml and a frequency of 20 Hz corresponding to specific energy input of 20,000 kJ/kg DM without major changes in particle size distribution. The results of this study indicate that the applied ultrasound treatment of fecal waste is not an effective method to increase short-term carbon bioavailability.

N-Acylhomoserine lactone (AHL)-acylase (also known as amidase or amidohydrolase) is a class of enzyme that belongs to the Ntn-hydrolase superfamily. As the name implies, AHL-acylases are capable of hydrolysing AHLs, the most studied signaling molecules for quorum sensing in Gram-negative bacteria. Enzymatic degradation of AHLs can be beneficial in attenuating bacterial virulence, which can be exploited as a novel approach to fight infection of human pathogens, phytopathogens or aquaculture-related contaminations. Numerous acylases from both prokaryotic and eukaryotic sources have been characterized and tested for the interference of quorum sensing-regulated functions. The existence of AHL-acylases in a multitude of organisms from various ecological niches, raises the question of what the physiological roles of AHL-acylases actually are. In this review, we attempt to bring together recent studies to extend our understanding of the biological functions of these enzymes in nature.

International audience; Estuaries are highly dynamic ecosystems in which freshwater and seawater mix together. Depending on tide and river inflows, particles originating from rivers or from the remobilization of sediments accumulate in the water column. Due to the salinity gradient and the high heterotrophic activity in the estuarine plume, hypoxic and anoxic microniches may form in oxygenated waters, sustaining favorable conditions for resuspended anaerobic microorganisms. In this context, we tested the hypothesis that anaerobic sulfate-reducing prokaryotes may occur in the water column of the Adour River. Using 16S ribosomal RNA (rRNA) and dsrAB-based terminal restriction fragment length polymorphism (T-RFLP) techniques, we characterized total prokaryotic and sulfate-reducing communities along a gradient from estuarine to marine bay waters. Sulfate-reducing prokaryotes were further characterized by the description of dsrB genes and the cultivation of sulfidogenic anaerobic microorganisms. As a result, physical-chemical parameters had a significant effect on water bacterial diversity and community structure along the studied gradient. The concentration of cultured sulfidogenic microorganisms ranged from 1 to 60 × 103 cells l−1 in the water column. Sulfate-reducing prokaryotes occurring in estuarine waters were closely related to microorganisms previously detected in freshwater sediments, suggesting an estuarine origin, mainly by the remobilization of the sediments. In the marine bay station, sediment-derived sulfate-reducing prokaryotes were not cultured anymore, probably due to freshwater dilution, increasing salinity and extended oxic stress. Nevertheless, isolates related to the type strain Desulfovibrio oceani were cultured from the diluted plume and deep marine waters, indicating the occurrence of autochthonous sulfate-reducing bacteria offshore.

Antibiotics-bacteria interactions depend on antibiotic concentration at the scale of bacteria. This study investigates how vancomycin penetrates into activated sludge flocs and can be sorbed on the bacteria and extracellular polymeric substances (EPS). The 3D structure of flocs was imaged using EPS auto fluorescence. The green fluorescent BODIPY (R) FL vancomycin was introduced in a microscopic chamber containing activated sludge and penetration of vancomycin into the flocs by diffusion was observed using time-lapse microscopy. The penetration depended on the floc structure, as long and large pores could go through the whole flocs making preferential path. The antibiotic concentration into the flocs was also found to depend on the sorption rate. BODIPY (R) FL vancomycin was found to bind preferentially into Gram(+) bacteria than on EPS. The vancomycin adsorption constant on bacteria according to the linear adsorption model, Kd(bacteria) was estimated to be 5 times higher (SD 2.6) than the adsorption constant on EPS Kd(EPS). These results suggest that antibiotic removal by sorption into wastewater treatment plants could change according to the amount of bacteria in the sludge. Moreover, antibiotic concentration at the scale of bacteria could be significantly higher than the concentration in the bulk solution and this should be taken into account when studying antibiotic activity or biodegradation.

The influence of salt (NaCl) on bacterial and archaeal communities in a submerged fixed bed bioreactor system for the treatment of urban wastewater was determined by DGGE and 454 pyrosequencing of PCR-amplified 16S ribosomal RNA gene fragments. Cluster analysis of DGGE fingerprints showed significant differences in the community structure dependent on the salt concentration in the influent. Proteobacteria was found to be the dominant bacterial phylum in all experiments, with a-Proteobacteria being the main order at low salinity and ¿-Proteobacteria the dominant order at high salinity. Euryarchaeota was the main archaeal phylum in all experiments, with all microorganisms corresponding to methanogenic archaea. Whereas bacterial a-diversity decreased as salinity increased, archaeal a-diversity increased with higher NaCl concentrations.

A review of the literature published in 2013 on topics relating to the fate of emerging environmental pollutants during wastewater treatment is presented. This review is divided into the following sections: emerging biological agents, estrogens, metals, nanomaterials, nutrients, persistent organic pollutants, pharmaceuticals and personal care products and herbicide, and trace organic contaminants.

As water shortages are increasing, the need for sustainable water treatment and the reuse of water is essential. Water reuse from wastewater can be accomplished in a membrane bioreactor (MBR) in the secondary activated sludge stage of a wastewater treatment plant. To remove viruses, dissolved organics and inorganics still present in the MBR permeate, nanofiltration (NF) can be applied. Nevertheless, the major drawback of nanofiltration membranes is the production of a concentrate stream that cannot be discharged to the environment. In this research we investigate the concept of a combined MBR and NF system with NF concentrate recirculation back to the MBR to produce reusable water in a sustainable way. Long-term continuous operation (1 year) shows that the NF permeate quality is riot impacted by the recirculation. Fouling on the NF membrane is mostly the result of inorganics, while organics (e.g. humic acids) do not have a major impact on NF fouling. In fact, the flux of the NF was enhanced by the presence of humic acids due to recirculation. However, the MBR showed increased fouling and consequently more frequent membrane cleaning. The results presented show that the continuous production of reusable water from wastewater in a combined MBR and NO process with NO concentrate recirculation can be successful. (C) 2013 Elsevier B.V. All rights reserved

Biofilm reactors are a promising biotechnology to eliminate pharmaceuticals from wastewater during tertiary treatment or in water works for drinking water production. This study aimed at investigating the effects of pulsed carbon feeding for promoting the co-degradation of indigenous pharmaceuticals from pre-treated wastewater in a fixed-bed porous biofilm reactor (slow sand filter). The addition of acetate (carbon source) resulted in three different enhancement/limitation effects, which were compound dependent: 1) atenolol and iohexol experienced enhanced co-degradation followed by constant (acetate independent) degradation; 2) metoprolol, iomeprol, diclofenac, propranolol and sulfamethizole co-degradation dependent on aerobic turnover, but inhibited at higher acetate concentrations (60–300 mg C/L); 3) sulfadiazine, sulfamethoxazole and trimethoprim were removed independently of oxygen and acetate concentration. Carbamazepine, ditriazoic acid, iopromide; tramadol and venlavaxine were not removed at any acetate dosage. Biofilm reactors can be employed for polishing treated wastewater, and the addition of a primary carbon source can enhance the performance of the bioreactor.

Activated sludge models have assumed that a portion of organic solids in municipal wastewater influent is unbiodegradable. Also, it is assumed that solids from biomass decay cannot be degraded further. The paper evaluates these assumptions based on data from systems operating at higher than typical sludge retention times (SRTs), including membrane bioreactor systems with total solids retention (no intentional sludge wastage). Data from over 30 references and with SRTs of up to 400 d were analysed. A modified model that considers the possible degradation of the two components is proposed. First order degradation rates of approximately 0.007 d–1 for both components appear to improve sludge production estimates. Factors possibly influencing these degradation rates such as wastewater characteristics and bioavailability are discussed.

A methane-producing biocathode that converts CO2into methane was studied electrochemically and microbiologically. The biocathode produced methane at a maximum rate of 5.1 L CH4/m2projected cathode per day (1.6 A/m2) at −0.7 V versus NHE cathode potential and 3.0 L CH4/m2projected cathode per day (0.9 A/m2) at −0.6 V versus NHE cathode potential. The microbial community at the biocathode was dominated by three phylotypes of Archaea and six phylotypes of bacteria. The Archaeal phylotypes were most closely related toMethanobacterium palustreandMethanobacterium aarhusense. Besides methanogenic Archaea, bacteria seemed to be associated with methane production, producing hydrogen as an intermediate. Biomass density varied greatly with part of the carbon electrode covered with a dense biofilm, while only clusters of cells were found on other parts. Based on our results, we discuss how inoculum enrichment and changing operational conditions may help to increase biomass density and to select for microorganisms that produce methane.

Pre-treatment is normally required to reduce or control the fouling of ultrafiltration (UF) membranes in drinking water treatment process. Current pre-treatment methods, such as coagulation, are only partially effective to prevent long-term fouling. Since biological activities are a major contributor to accumulated fouling, the application of an oxidation/disinfection step can be an effective complement to coagulation. In this study, a novel pre-treatment method has been evaluated at laboratory scale consisting of the addition of low dose ozone into the UF membrane tank after coagulation and the use of a hollow-fibre membrane coated with/without MnO2 nanoparticles over a test period of 70 days. The results showed that there was minimal fouling of the MnO2 coated membrane (0.5 kPa for 70 days), while the uncoated membrane experienced both reversible and irreversible fouling. The difference was attributed to the greatly reduced presence of bacteria and organic matter because of the catalytic decomposition of ozone to hydroxyl radicals and increase of the hydrophilicity of the membrane surface. In particular, the MnO2 coated membrane had a much thinner cake layer, with significantly less polysaccharides and proteins, and much less accumulated organic matter within the membrane pores.

For the application of biofilm processes, a better understanding of nitrous oxide (N2O) formation within the biofilm is essential for design and operation of biofilm reactors with minimized N2O emissions. In this work, a previously established N2O model incorporating both ammonia oxidizing bacteria (AOB) denitrification and hydroxylamine (NH2OH) oxidation pathways is applied in two structurally different biofilm systems to assess the effects of co- and counter-diffusion on N2O production. It is demonstrated that the diffusion of NH2OH and oxygen within both types of biofilms would form an anoxic layer with the presence of NH2OH and nitrite ( "Equation missing"), which would result in a high N2O production via AOB denitrification pathway. As a result, AOB denitrification pathway is dominant over NH2OH oxidation pathway within the co- and counter-diffusion biofilms. In comparison, the co-diffusion biofilm may generate substantially higher N2O than the counter-diffusion biofilm due to the higher accumulation of NH2OH in co-diffusion biofilm, especially under the condition of high-strength ammonium influent (500 mg N/L), thick biofilm depth (300 μm) and moderate oxygen loading (~1–~4 m3/d). The effect of co- and counter-diffusion on N2O production from the AOB biofilm is minimal when treating low-strength nitrogenous wastewater.