Acumulação de polihidroxialcanoatos por culturas microbianas mistas do tratamento do efluente urbano

Os microrganismos podem acumular intracelularmente inclusões de polihidroxialcanoatos (PHAs) durante o tratamento de águas residuais, utilizando o efluente urbano como fonte de carbono. Estes polímeros biodegradáveis surgem como alternativa aos plásticos convencionais, permitindo reduzir a quantidade de lamas enviadas para tratamento posterior. A monitorização da acumulação de PHAs nos microrganismos das lamas ativadas da ETAR de Penices foi efetuada durante 30 dias, recorrendo ao método de Cromatografia Gasosa (CG) e à técnica de coloração de Negro Sudão B (NSB). Os resultados obtidos por CG revelaram uma acumulação máxima, em fração mássica, de PHAs igual a 5.3 % nas lamas ativadas, relativamente ao teor de biomassa liofilizada e uma concentração máxima de 127 mg L-1. Os resultados obtidos por NSB corroboraram estes valores, pelo que esta técnica poderá ser uma alternativa viável para a quantificação de PHAs, sendo mais fácil de operar e menos dispendiosa. Concluiu-se ainda que a produção de PHAs com culturas mistas à escala industrial para este caso de estudo não é viável, dadas as baixas quantidades obtidas de polímero e o elevado investimento em unidades de extração e purificação do mesmo.The microorganisms can accumulate intracellularly inclusions of polyhydroxyalkanoates (PHAs) during wastewater treatment, using the urban efluent as carbon source. These biodegradable polymers appear to emerge as an alternative to conventional plastics, allowing to reduce the amount of activated sludge sent to posterior treatment. The monitoring of the PHAs accumulation in the activated sludge microorganisms of the Penices wastewater treatment facility was performed for 30 days, using gas chromatography (GC) and Sudan Black B (SBB) staining. GC results revealed a maximum accumulation of PHAs mass fraction of 5.3 % in the activated sludge, in relation to the liophilized biomass content, and a maximum concentration of 127 mg L -1 . The SBB results corroborated these values, and therefor this technique can be a viable alternative to the PHAs quantification, being easier to operate and less costly. Still, it was possible to conclude that the PHAs production with mixed cultures at the industrial scale is not viable in this case, given the obtained low quantities of polymer and the high investment in extraction and purification units

Removal of ibuprofen by an aerobic activated sludge system

O aumento de compostos farmacêuticos no meio ambiente levou à procura de métodos eficientes e amigos do ambiente capazes de solucionar o problema. Neste trabalho é proposta a utilização de lamas ativadas para a remoção de ibuprofeno (IBU). Foram testadas diferentes concentrações de IBU (0.4, 0.5, 0.6, 0.8 e 1 mg L-1), em sistema fechado, num reactor de 4 L. Foram calculados valores de uptake e percentagem de remoção. Os valores de uptake cresceram com o aumento da concentração inicial de IBU (0.192 para 0.660 mg g-1), o que está de acordo com o teoricamente esperado. A remoção foi quase total (99.1-99.5 %) sendo independente da concentração inicial de IBU. O mecanismo de remoção é bem descrito pelo modelo de pseudo- 2ª ordem, para todas as concentrações testadas. O sistema utilizado mostrou ser eficiente na remoção de IBU e poderá ser utilizado na remoção de IBU em grande escala.The increasing presence of pharmaceutical compounds in the environment leads to the search of efficient and eco-friendly methods able to solve the problem. This work proposes the use of activated sludge for the removal of ibuprofen (IBU). Different concentrations of IBU were tested (0.4, 0.5, 0.6, 0.8, and 1 mg L-1) in a batch reactor with a working volume of 4 L. The uptake values and removal percentage were calculated. The uptake values increased with increasing initial concentration of IBU (0.192 to 0.660 mg g-1 ), which is in agreement with the theoretically expected. The removal was almost total (99.1-99.5 %) and independent of the initial IBU concentration. The removal mechanism is well described by the pseudo 2nd order model, for all concentrations tested. The system is efficient in removing IBU and may be used in the removal of IBU in large scale.Fundação para a Ciência e a Tecnologia (FCT) através do projecto de financiamento estratégico à unidade de investigação (UID/BIO/04469/2013), COMPETE 2020 (POCI-01-0145-FEDER-006684)Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BPD/82558/2011; SFRH/BPD/101338/2014

Removal of paracetamol by an activated sludge bioreactor

the increased presence in wastewaters, rivers and other aquifers is of environmental concern. The search for new technologies that can solve the problem is imperative. This work proposes the use of activated sludge for paracetamol (PARA) removal. Different PARA concentrations were tested (0.4, 0.5, 0.6, 0.8, and 1 mg L-1) in a batch reactor with a working volume of 4 L. The uptake values increased with increasing initial PARA concentration, from 0.104 to 0.341 mg g-1, in agreement with the theoretically expected. The removal percentage ranged from 93.3 to 98.8 decreasing with the increase on the initial concentration. The removal mechanism is well described by the pseudo 1st order model and pseudo 2nd order model, for all concentrations tested.info:eu-repo/semantics/publishedVersio

Characterization of the effects of pharmaceuticals in activated sludge using quantitative image analysis

Microbiotec'17 - Congress of Microbiology and Biotechnology 2017Background: The extensive use of personal care products and pharmaceuticals for human consumption and veterinary usage led to the detection of these products in wastewater effluents and aqueous systems as rivers, surface waters and others. The ecotoxicology of pharmaceuticals was well studied by Backhaus [1]. The effect of these compounds on microorganisms is also an important study that should be taken into account when biological processes are used to remove these compounds from aqueous systems. Quantitative image analysis (QIA) is considered a useful technique for biological processes monitoring when combined to microscopy. The aim of this study was to analyze the effects of ibuprofen (IBU), paracetamol (PARA), and ethynylestradiol (EE2) on the biomass morphology using QIA.The authors thank the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, COMPETE 2020 (POCI-01-0145-FEDER-006684) and BioTecNorte operation (NORTE-010145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. The authors also acknowledge the financial support to Cristina Quintelas through the postdoctoral grant (SFRH/BPD/101338/2014) provided by FCT – Portugal.info:eu-repo/semantics/publishedVersio

Distinção de fenómenos de bulking em lamas activadas por técnicas de análise de imagem

No corrente trabalho pretendeu-se detectar e identificar diferentes tipos de perturbações em lamas activadas (bulking filamentoso, bulking viscoso e crescimento de flocos pin point) por técnicas de processamento e análise de imagem. Para o efeito foram determinados os parâmetros operacionais sólidos suspensos totais (SST) e índice volumétrico de lamas (IVL), assim como diversos parâmetros morfológicos (conteúdo e morfologia da biomassa agregada e filamentosa), obtidos por análise de imagem. Os resultados obtidos permitiram o esclarecimento das diferentes inter-relações presentes entre cada uma das condições estudadas e os parâmetros que caracterizaram a biomassa microbiana, assim como a aferição do parâmetro operacional IVL, a partir da caracterização da biomassa

Study of chemical oxygen demand and ammonia removal efficiencies by image analysis and multivariate statistics tools

Activated sludge systems are frequently used in wastewater treatment for chemical oxygen demand (COD) and ammonia removal. However, several problems can affect the operation of these systems leading to abnormal conditions such as filamentous bulking, viscous bulking and pinpoint flocs, among others. These occurrences, which may lead to the decrease of COD and ammonia removal efficiencies, are linked to biomass morphological and physiological changes and can be studied by microscopic evaluation. However, traditional microscopic inspection by a human operator, and correspondent manual assessment, is a subjective and labor intensive procedure. Automated image processing and analysis presents considerable convenience in such cases. For this study, a lab-scale activated sludge reactor was operated for 100 days and monitored through microscopic staining and image analysis. The operational parameters were modified inducing the above mentioned abnormal conditions, apart from the normal operation. Biomass morphology was obtained by bright field microscopy combined with grayscale image processing. Biomass physiology was also studied by employing epifluorescence combined with color image processing. The LIVE/DEAD® BacLight™ Bacterial Viability Kit was employed to determine the biomass viability, and the LIVE BacLight™ Bacterial Gram Stain Kit for the biomass Gram status. Two ad-hoc Matlab specially developed programs were employed. COD and ammonia removal efficiencies were studied by clustering the data points in two large clusters: “95% or above” and “below 95%” for the COD, and “90% or above” and “below 90%” for ammonia. These clusters were selected based on the behavior of these two parameters throughout the experiment time. The results showed that the COD removal efficiency was well predicted by the best 10 physiological parameters with an overall accuracy of 94.1%, for the ensemble of the tested conditions. Relatively high accuracies of 90.6% and 91.2% were also obtained for the ammonia removal efficiency regarding the best 9 physiological and morphological parameters, respectively. Thus, for the ammonia removal efficiency both types of parameters are equally useful, leading to 95.3% accuracy when the best 3 physiological and 6 morphological parameters were used

Monitoring filamentous bulking and pin-point flocs in a lab-scale activated sludge system using image analysis

Activated sludge processes are the most frequently used techniques regarding biological wastewater treatment. However, depending on the process operation conditions, several malfunctions could take place, in which filamentous bulking and deflocculation processes, such as pin-point flocs, are the most common problems, causing the sludge settling ability decrease and effluent quality deterioration. Bright field Image analysis is nowadays considered a powerful tool to quantitatively characterize aggregated and filamentous bacteria. Furthermore, the use of epifluorescent staining techniques, coupled to image analysis, presents a promising method to determine bacteria gram nature and viability. Encouraged by the success of image analysis procedures over the last years, the present work studied a lab-scale activated sludge system, under operation conditions causing filamentous bulking and pin-point flocs phenomena. Sludge settling ability and turbidity values were measured verifying the nature of the settling problem. COD contents, as well as nitrogen contents, in terms of N-NH4+, N-NO3- and N-NO2-, were surveyed in the feeding effluent, reactor bulk and settler. Regarding the biomass characterization, four major morphological descriptors groups were studied, covering free filamentous bacteria contents, aggregates contents, aggregates size and aggregates morphology. With respect to the aggregates characterization, these were divided in 3 classes (large, intermediate and small aggregates) according to their size. Percentages of gram-positive bacteria, gram-negative bacteria, viable and damaged bacteria were also evaluated based on fluorescent image analysis. Finally, the raw resulting data was fed into a multivariate statistical analysis, in order to enlighten the relationships between the obtained image analysis information and operational parameters. An improvement of the sludge morphological characterisation was found by combining fluorescent and bright field image analysis procedures. Furthermore, the results obtained during the monitoring period indicate that automated image analysis can help clarifying the nature of the events within the aeration tank, when the system is submitted to disturbances

Automatic identification of activated sludge disturbances and assessment of operational parameters

Activated sludge systems are prone to be affected by changes in operating conditions leading to problems such as pinpoint flocs formation, filamentous bulking, dispersed growth, and viscous bulking. These problems are often related with the floc structure and filamentous bacteria contents. In this work, a lab-scale activated sludge system was operated sequentially obtaining filamentous bulking, pinpoint floc formation, viscous bulking and normal conditions. Image processing and analysis techniques were used to characterize the contents and structure of aggregated biomass and the contents of filamentous bacteria. Further principal component and decision trees analyses permitted the identification of different conditions from the collected morphological data. Furthermore, a partial least squares analysis allowed to estimate the sludge volume index and suspended solids key parameters. The obtained results show the potential of image analysis procedures, associated with chemometric techniques, in activated sludge systems monitoring.The authors acknowledge the financial support to D.P.M. through the post-doctoral grant SFRH/BPD/82558/2011 and to the Project PTDC/EBB-EBI/103147/2008 both funded by Fundacao para a Ciencia e a Tecnologia (Portugal) and Fundo Social Europeu (FSE)

Quantitative Image Analysis: a monitoring tool in wastewater treatment

Book of Abstracts of CEB Annual Meeting 2017[Excerpt] Computers are key equipment for the analysis of large amounts of data, for tasks requiring complex computation, and for the extraction of quantitative information, opposite to the qualitative evaluation of human analysis. Today, the automatic analysis of numerical images captured by digital cameras enables to rapidly extract quantitative information. Thus, quantitative image analysis (QIA) can be defined in general terms as the extraction of significant information from images, by means of digital image processing and analysis techniques. In the last twenty years, QIA have gained an unquestionable role in several fields of research worldwide and our lab is considered a pioneer research unit on the development of QIA procedures for biological wastewater treatment processes monitoring. Over the years, the number of QIA studies [1, 2] for aggregated (granules and flocs) biomass and filamentous bacteria characterization has been increasing. It should be noticed, though, that some difficulties may be encountered in QIA procedures related to the suitability of the employed microscopy technique, regarding the intended biological process characterization. [...]info:eu-repo/semantics/publishedVersio