How can the Functioning of Treatment Wetlands be Enhanced?

Wetlands have already been recognized to hold the capacity for efficiently reducing or removing large amounts of pollutants from point sources (e.g. municipal and certain industrial effluents) as well as non-point sources (e.g. mining, agricultural and urban runoff) including organic matter, suspended solids, excess of nutrients, pathogens, metals and other micropollutants. This pollutants removal is accomplished by the interdependent action of several physical, chemical and biological processes which include sedimentation, filtration, chemical precipitation, sorption, biodegradation, and plants uptake among others. The mechanisms and the interdependences among the wetlands’ components (water, substrate and biota) are complex and not yet entirely understood, although some progresses have been achieved in the latest years as the awareness to the water depurative functions of wetlands becomes more widespread. In fact, studies have led to both a greater understanding of the potential of natural wetland ecosystems for pollutants assimilation and the design of new natural water treatment systems inspired in these natural systems, the constructed wetlands systems (CWS). These CWS can be defined as man-made systems that have been designed and constructed to utilize the natural processes involving wetland vegetation, soils, and their associated microbial populations to assist in treating wastewater. They are designed to take advantage of many of the same processes that occur in natural wetlands, but do so within a more controlled environment. However, until now these systems have been approached primarily as a “black-box”, without a thorough understanding of the processes involved. Ultimately, the optimization of CWS for the removal of more specific target compounds requires a basic knowledge of the processes involved in the removal of the pollutants and the interactions between those and the CWS components. New trends in CWS research are moving towards the study of such processes and interactions and focus on the selection and optimization of the CWS components for more specific applications. The aim of this work is to present a review on the main pollutant removal and transformation mechanisms in wetlands, the pollutants fate in the system and the roles played by the most important components of CWS (water, substrate and biota) in the processes and how they affect the overall treatment system performance. Some focus will be given to the most recent studies published on this subject especially those involving the treatment of micropollutants by CWS and the mechanisms that may be involved in the removal of these particular substances. Some of the questions remaining to be addressed about the removal mechanisms in CWS and the aspects of CWS operation that still require optimization will also be highlighted in this review

Phytoremediation: An Option for Removal of Organic Xenobiotics from Water

Pollution by persistent organic pollutants (pesticides, pharmaceuticals, petroleum hydrocarbons, PAHs, PCBs, etc.) is an environmental problem that is recognized worldwide. In order to address this problem, cost effective technologies have been developed and evaluated for the decontamination of soil and water resources. Phytoremediation is a promising technology that uses plants and the associated rhizosphere microorganisms to remove, transform/detoxify, or accumulate organic and inorganic pollutants present in soils, sediments, surface or ground water, wastewater, and even the atmosphere. In fact, as a result of their sedentary nature, plants have evolved diverse abilities for dealing with toxic compounds in their environment. They, therefore, possess a variety of pollutant attenuation mechanisms that makes their use in remediating contaminated land and water more feasible than physical and chemical remediation. Currently, phytoremediation is used for treating many classes of organic xenobiotics including petroleum hydrocarbons, chlorinated solvents, polycyclic aromatic hydrocarbons, pesticides, explosives, pharmaceutical compounds and their metabolites, and it involves several decontamination mechanisms. There are several different types of phytotechnologies such as, for instance, treatment constructed wetlands. The aim of this work is to present a review on the application of phytoremediation technologies for water decontamination from persistent organic pollutants, with special emphasis focused on the removal of a class of emergent pollutants that has recently been receiving a lot of attention, the pharmaceutically active compounds. Within the realm of phytotechnologies, constructed wetlands for wastewater treatment are dedicated a special focus as these systems have been used with success for the removal of several different types of organic xenobiotics

Studies on pharmaceuticals removal from water potential use of constructed wetlands systems

Pharmaceutical residues in the environment and their potential toxic effects have been recognized as one of the emerging research areas in environmental chemistry. Many reports are available in the literature about the detection of several of the most consumed pharmaceuticals, their metabolites and transformation products in effluents of domestic wastewater treatment plants (WWTPs) as well as surface and ground waters and even, in drinking waters worldwide. This situation can be attributed to the general inadequacy of conventional treatment processes used. in WWTPs in dealing with trace pollutants. An option for removal of organic xenobiotics from WWTPs effluents is the implementation of constructed wetlands systems (CWS). In comparison with other tertiary or advanced treatment technologies, CWS present the advantage of being an essentially low-cost and low-maintenance technology. CWS have been already applied with success for the treatment of other organic xenobiotics, but their use for pharmaceuticals removal has been only scarcely tested. Moreover, these systems have been approached primarily as a "black-box", without a thorough understanding of the processes involved. The efficiency of CWS in the removal of pollutants can be significantly enhanced by using adequate support matrices with a greater capacity to retain contaminants by sorption phenomena, ionic exchange or other physico-chemical processes and plant species with high capacity to tolerate and remove pollutants froco contaminated waters. The main goal, of this work was to evaluate the ability of a microcosm CWS to remove selected pharmaceuticals from domestic wastewater that has received secondary treatment. The selection of the pharmaceuticals to be studied was based on the following criteria: data on consumption and presence in the environment, behavior in. WWTPs, and characteristics such as biodegradability, acid-base character, hydrophobicity and water solubility. Four pharmaceuticals were selected, in particular two acidic substances (ibuprofen, IB, and clofibric acid, CA), a neutral one (carbamazepine, CB) and another with an alkaline character (atenolol, AT). These are moderately lipophilic compounds, with the exception of AT, which is a somewhat hydrophilic substance. Among these, one of the compounds is biodegradable (IB), another one is only moderately biodegradable (AT), whereas the other two (CA and CB) are hardly biodegradable. /RESUMO - A qualidade da água é uma das grandes preocupações actuais em química analítica ambiental. Em particular, a ocorrência e destino de fármacos no ambiente aquático tem vindo a ser reconhecido como um dos problemas emergentes nesta área. De facto, a frequente detecção de fármacos utilizados em medicina humana, seus metabolitos e produtos de transformação em efluentes de estações de tratamento de águas residuais urbanas (ETARs) bem como em águas naturais, superficiais e subterrâneas, e até mesmo em águas para consumo, tem demonstrado a existência de um problema real devido à crescente quantidade e diversidade de substâncias deste tipo que são excretadas e libertadas nos sistemas de recolha de efluentes líquidos urbanos. Como consequência da geralmente baixa eficiência de remoção destes contaminantes pelos processos de tratamento convencionais utilizados na maioria das ETARs, resulta que muitas destas substâncias acabam por ser descarregadas com os efluentes nos meios receptores hídricos e disseminadas pelos meios aquáticos. As implicações resultantes desta descarga de fármacos no ambiente aquático sugerem a urgente necessidade de encontrar processos complementares ou alternativos para a sua remoção dos efluentes antes de alcançarem os cursos de água. A utilização de processos de tratamento terciário ou de afinação nas ETARs, como por exemplo a utilização de processos de membranas ou oxidação química, podem permitir o aumento das eficiências de remoção obtidas. No entanto, a implementação e manutenção deste tipo de processos têm custos elevados e são dificeis de adaptar para uma utilização em larga escala em ETARs. Os leitos construídos de macrófitas (LCMs) têm surgido ultimamente como sistemas complementares ou, nalguns casos, alternativos de tratamento de águas residuais urbanas. Os LCMs, ou zonas húmidas construídas, são sistemas artificiais projectados e construidos para tirar partido do mesmo tipo de processos que ocorrem nas zonas húmidas naturais, utilizando vegetação, solos e colónias de microorganismos típicas destes sistemas, mas actuando de uma forma controlada e optimizada com o propósito de aplicação para tratamento de efluentes. Os mecanismos de tratamento nos LCMs são extremamente diversificados, caracterizados por uma interacção complexa de processos fisicos, químicos e biológicos, que ocorrem ao nível das plantas, da matriz de suporte e dos microrganismos adaptados à toxicidade do efluente

Constructed wetlands with light expanded clay aggregates for agricultural wastewater treatment

Constructed wetlands (CWs) are receiving a renewed attention as a viable phytotechnology for treating agricultural wastewaters and for the removal of more specific pollutants, in particular recalcitrant ones. In this work, the performance of CW mesocosms using light expanded clay aggregates (LECA) as the bed's substrate and planted with Phragmites australis was investigated for treatment of olive mill wastewater (OMW), swine wastewater (SW) contaminated with oxytetracycline and water contaminated with herbicide MCPA (2-methyl-4-chlorophenoxyacetic acid). Both wastewaters (OMW and SW) initially presented high organic matter content and total suspended solids which were removed by the system with efficiencies higher than 80%. Removal of polyphenols in OMW and nitrogen compounds in SW also showed similar or higher efficiencies in comparison with other treatment systems reported in the literature. The antibiotic oxytetracycline was completely removed from SW within the assay period in unplanted LECA beds, but planted beds allowed a significantly faster removal. In regard to water contaminated with MCPA, the results showed that LECA has a large sorption capacity for this herbicide (removal efficiencies of 56-97%). In general, considerably higher pollutant removal efficiencies were obtained when plants were used (up to 28% higher). The results obtained are indicative that CWs with LECA as substrate may be an adequate option for agricultural wastewater treatment

"Wetlands: Water Living Filters?",

Human societies have indirectly used natural wetlands as wastewater discharge sites for many centuries. Observations of the wastewater depuration capacity of natural wetlands have led to a greater understanding of the potential of these ecosystems for pollutant assimilation and have stimulated the development of artificial wetlands systems for treatment of wastewaters from a variety of sources. Constructed wetlands, in contrast to natural wetlands, are human-made systems that are designed, built and operated to emulate wetlands or functions of natural wetlands for human desires or needs. Constructed wetlands have recently received considerable attention as low cost, efficient means to clean-up not only municipal wastewaters but also point and non-point wastewaters, such as acid mine drainage, agricultural effluents, landfill leachates, petrochemicals, as well as industrial effluents. Currently, untreated wastewater discharge in the natural wetlands sites is becoming an increasingly abandoned practice whereas the use of constructed wetlands for treatment of wastewater is an emerging technology worldwide. However, natural wetlands still play an important role in the improvement of water quality as they act as buffer zones surrounding water bodies and as a polishing stage for the effluents from conventional wastewater treatment plants, before they reach the receiving water streams. In fact, one of the emerging issues in environmental science has been the inefficiency of wastewater treatment plants to remove several xenobiotic organic compounds such as pesticides and pharmaceutical residues and consequent contamination of the receiving water bodies. Recent studies have shown that wetlands systems were able to efficiently remove many of these compounds, thus reaffirming the importance of the role which can be played by wetlands in water quality preservation. The aim of this work is to present a review on the application of wetlands as “living” filters for water purification, with special emphasis focused in the removal of micropollutants, especially xenobiotic organic compounds such as pharmaceuticals and pesticides residues, which are not efficiently removed by conventional wastewater treatment plants. Furthermore, the role of wetlands as protection zones which contribute to the improvement of the aquatic ecosystems’ quality will be discussed

Organic xenobiotics removal in constructed wetlands, with emphasis on the importance of the support matrix

Constructed wetlands (CWs) are increasingly popular as an efficient and economical alternative to conventional wastewater treatment processes for removal, among other pollutants, of organic xenobiotics. In CWs, pollutants are removed through the concerted action of their components, whose contribution can be maximized by careful selection of those components. Specifically for non-biodegradable organic pollutants, the materials used as support matrix of CWs can play a major role through sorption phenomena. In this review the role played by such materials in CWs is examined with special focus on the amount of research that has been conducted to date on their sorption properties relatively to organic compounds. Where available, the reports on the utilization of some of those materials on pilot or full-scale CWs are also recognized. Greatest interest has been directed to cheaper and widely available materials. Among these, clays are generally regarded as efficient sorbents, but materials originated from agricultural wastes have also gained recent popularity. Most available studies are lab-scale batch sorption experiments, whereas assays performed in full-scale CWs are still scarce. However, the available lab-scale data points to an interesting potential of many of these materials for experimentation as support matrix of CWs targeted for organic xenobiotics removal

Removal Processes of Pharmaceuticals in Constructed Wetlands

Over the latest years the occurrence of pharmaceutical residues in the environment has been motivating an increasing concern over the possible harmful effects of many of these pollutants to living organisms. In fact many reports are available in the literature about the detection of several of the most consumed pharmaceuticals, their metabolites and transformation products in wastewaters as well as surface and ground waters and even in drinking waters worldwide. This situation can be attributed to the general inadequacy of the conventional treatment processes used in wastewater treatment plants (WWTPs) in dealing with trace pollutants. The reason for the low efficiencies of conventional WWTPs for removal of pharmaceuticals is the fact that these plants were designed to remove bulk constituents of wastewater such as suspended solids, dissolved biodegradable organic matter, pathogens and nutrients and not for also dealing with trace pollutants in general. Due to the highly variable physical and chemical properties of these organic compounds, the efficiencies by which they are removed may vary substantially. Despite the low concentration levels at which pharmaceuticals are generally present in the environment, there is a significant potential for synergistic effects between compounds with similar modes of action or related therapeutic targets, which is enough to be of serious concern. Therefore, there is an urgent need to find ways of retaining and removing these pollutants before they reach the receiving water bodies. Optimization of the WWTP processes has been tried by increasing hydraulic and solid retention times, for example. In addition, some advanced technologies have been evaluated to decrease their discharge into water bodies. However, despite the sometimes high removal efficiencies attained, these processes are generally not cost-effective on a large scale. In fact, it remains a crucial necessity to find applicable technologies for removing pharmaceuticals from wastewater with higher efficiencies at reasonable cost of operation and maintenance. Constructed wetlands systems (CWS) are being increasingly used as an option to remove micropollutants, in particular organic xenobiotic compounds, from wastewaters. There is a vast range of studies highlighting the high efficiencies of these systems in removing a wide variety of compound types, including some pharmaceuticals. For this reason, this type of systems are being adopted as a tertiary treatment option in domestic wastewater treatment and, also, at least as part of the specialized wastewater treatment plants of some industries (such as chemical, dye, tannery, livestock, etc.). Often CWS have been studied under a “black box” approach where only influent and effluent pollutants concentrations were assessed and no further in-depth investigations were pursued. However, in order to use CWS as a more efficient response to new challenges such as those presented by the more recalcitrant micropollutants, a thorough characterization of the processes involved in pollutants removal in CWS is direly needed, as well as some understanding of the ways the several CWS components (solid matrix, vegetation and microorganisms) may interact with each other synergistically. This, in fact, has been an effort which increasingly has been undertaken in the most recent years as a new trend in CWS research, not only in field studies but also in numerous lab studies as well. As result of the increases knowledge of such processes and interactions, a better guidance in the selection and optimization of the CWS components for more specific applications becomes possible. In this work we intend to present a review of the main pharmaceutical removal and transformation processes in CWS, the roles played by the most important components of CWS in such processes and how the overall treatment system performance is affected by all these. Some attention will be given to the most recent studies published on this subject, especially those involving specific CWS application for the removal of pharmaceuticals and which focus on the characterization/optimization of processes or the selection of CWS components. Some of the questions remaining to be addressed about the removal mechanisms in CWS and the aspects of CWS operation that still require optimization will also be highlighted in this work

Deteção e caracterização molecular de Babesia spp. em Canis familiaris e de outros agentes transmitidos por ixodídeos na Área Metropolitana de Lisboa e Oeste, Portugal

Dissertação de Mestrado Integrado em Medicina VeterináriaAs doenças dos canídeos cujos agentes são transmitidos por vetores (DCTV), são causadas por um número abrangente de agentes patogénicos transmitidos por artrópodes e são um problema crescente no mundo nos últimos anos. A Babesiose canina faz parte dessas doenças, sendo causada por diversas espécies pertencentes ao género Babesia. Até ao momento sabe-se que a Babesiose canina é provocada pelas espécies Babesia canis e Babesia microti-like no Norte e Babesia vogeli em todas as regiões de Portugal. No entanto, as informações relativas às espécies de Babesia, bem como a sua prevalência molecular, distribuição geográfica e a gravidade do quadro clínico são escassas. A pesquisa de possíveis agentes transmitidos por vetores é igualmente importante, uma vez que os cães podem estar infetados com múltiplos destes agentes patogénicos, o que torna a abordagem clínica e tratamento um desafio para o Médico Veterinário. A amostra deste estudo foi constituída por dois grupos, de forma a contribuir para uma perceção real dos agentes patogénicos encontrados em 94 animais aparentemente saudáveis, provenientes de canis, e 49 animais doentes com suspeita de Babesiose canina, ambos provenientes da área metropolitana de Lisboa e do Oeste. Este estudo baseou-se na deteção de Babesia e agentes coinfetantes o método de observação de esfregaços sanguíneos ao Microscópio ótico, PCR convencional, RFLP e sequenciação de DNA. A infeção por B. canis foi detetada apenas no grupo de animais doentes, em 2 cães (1,40%) com um quadro clínico descrito e compatível com Babesiose canina aguda, enquanto a espécie B. vogeli foi detetada em 1 animal doente e 3 animais aparentemente saudáveis (2,81%). Foram detetadas infeções únicas em 35 animais (24,64%), dos quais: 17 (11,97%) com Hepatozoon canis, 4 (2,82%) com Anaplasma platys, 1 (0,70%) com Ehrlichia canis e 7 (4,93%) com Mycoplasma haemocanis. As coinfeções foram detetadas em 13 animais (9,15%), dos quais: 5 (3,52%) com H. canis e A. platys; 5 (5,52%) com H. canis e M. haematoparvum; e 1 (0,70%) com A. platys e M. haematoparvum. A partir do grupo de animais aparentemente saudáveis, a prevalência de infeções únicas e coinfeções foi de 26,6%, e de 12,7% respetivamente. Esta foi a primeira identificação, a partir de métodos moleculares, de Babesia canis e Mycoplasma haematoparvum no Sul de Portugal. A identificação de agentes transmitidos por vetores auxilia os Médicos Veterinários na sua abordagem clínica e reforça a importância de atuar de acordo com o conceito One Health para a prevenção dos riscos de transmissão.ABSTRACT - DETECTION AND MOLECULAR CHARACTERIZATION OF BABESIA SPP. IN CANIS FAMILIARIS AND OTHER PATHOGENS TRANSMITED BY TICKS IN THE METROPOLITAN AREA OF LISBON AND WESTERN REGION, PORTUGAL - Canine vector-borne diseases (CVBD) are caused by a wide range of pathogens transmitted by arthropods, and it is an issue of growing importance from the past years. Canine Babesiosis is englobed in this group of diseases, furthermore is caused by different species from the Babesia genera. Currently it’s known that Canine Babesiosis it’s caused in the northern of Portugal by Babesia canis and Babesia microti-like, and by Babesia vogeli in all the country. There is a lack of information about the species that could cause the disease in Portugal, as well as the molecular prevalence, geographic distribution and severity of clinical manifestations of these parasites. Also, the detection of possible pathogens transmitted by vectors are equally important since the dogs can be infected with multiple pathogens, which makes the clinical approach and treatment a challenge for veterinarians. This study includes two groups, with the aim of contribution for a real perspective of pathogens that can be found, both the metropolitan area of Lisbon and Western region of Portugal. 94 dogs apparently healthy from shelters, that had previous contact with ticks, and 49 dogs clinically suspected of Canine Babesiosis. This study assessed, by means of blood smear examination, conventional PCR, RFLP and DNA nucleotide sequencing, the presence of Babesia spp. and co-infecting agents. Babesia canis was detected only in the group of sick dogs, in two animals (1,40%), with clinical manifestations described and compatible with an acute Canine Babesiosis, while B. vogeli was detected in one animal suspect of disease and 3 animals apparently health (2,81%). Single infections were detected in 35 animals (24,64%): H. canis in 17 (11,97%), A. platys in 4 (2,82%), E. canis in 1 (0,70%) and M. haemocanis in 7 (4,93%). Coinfections were detected in 13 animals (9,15%): H. canis and A. platys in 5 (3,52%); H. canis and M. haematoparvum in 5 (5,52%) and A. platys with M. haematoparvum in 1 (0,70%). In dogs apparently healthy the prevalence of single infections and coinfections was 26,6%, and 12,7% respectively. This is the first molecular identification of B. canis and M. haematoparvum in dogs from southern Portugal. This identification of pathogens of CVBD agents helps to guide the clinical approach of veterinarians at the practice and reinforces the importance of a One Health approach, to prevent the risk of the transmission.N/

Pilot-scale study on the removal of pharmaceuticals by LECA based SSF-constructed wetlands

In recent years, the occurrence and fate of pharmaceutically active compounds (PhACs) in the aquatic environment has been recognized as one of the emerging issues in environmental chemistry. Some compounds are just resistant to degradation in the sewage treatment plants (STPs) while others, although suffering partial degradation, still end up in receiving water bodies due to the large inputs received in STPs [1]. Clofibric acid (a metabolite from a series of widely used blood lipids lowering agents), ibuprofen (an anti-inflamatory non-prescription drug) and carbamazepine (an anticonvulsant and mood stabilizing drug) are some of the most frequently found PhACs in environmental monitoring studies [1]. Wastewater treatment by sub-surface flow constructed wetland systems (SSF-CWs) is a low-cost technology that has shown some capacity for removal of several organic xenobiotic pollutants, but fewer studies exist on pharmaceuticals behavior. The aim of the present work was to evaluate the efficiency of a pilot SSF-CW assembled with the plants cattail (Typha spp.) and a clay material (LECA 2/4) as support matrix, for the removal of three pharmaceuticals, namely ibuprofen (IB), carbamazepine (CB) and clofibric acid (CA), from contaminated wastewaters. Four beds were planted with pre-grown cattails (density of 80 plants/m2) and four were left unplanted to be used as controls. Experiments were conducted both in batch and in continuous mode with a flooding rate of 100%. Pharmaceutical concentrations were quantified by HPLC with UV detection at 210 nm (CB), 222 nm (IB) and 230 nm (CA). Solid phase extraction was used for sample pre-concentration whenever the measured pharmaceutical concentrations fell under the limit of quantification of the analytical method. The physico-chemical characterization of the support matrix material, LECA, involved the determination of properties such as pH, point of zero charge, electrical conductivity, apparent porosity, bulk density and hydraulic conductivity. In order to shed some light on the tolerance mechanisms developed by Typha spp. in the presence of these pharmaceuticals, biochemical and physiological parameters were evaluated. Typha spp. showed good tolerance to the presence of CA, CB and IB concentrations of 1 mg L-1, which is a value much higher than those usually reported in wastewaters. LECA alone was able to remove about 90% of the initial amounts of CB and IB in solution, and 50% of CA. IB was very susceptible to microbial degradation and up to 80% of the initial concentration could be removed by the microbial population present in the wastewater used. Overall, the CWS shows a higher removal performance for CA, CB and IB than any of its individual components (plants, support matrix, microorganisms) considered separately. CA proved to be the most resilient compound, which comes in agreement with other published data. However, this system enabled the removal of substantially higher amounts of CA than has previously been reported in other studies. The use of systems of this kind for the removal of pharmaceuticals from wastewaters seems like a promising alternative to the less efficient processes of conventional wastewater treatment

Study on the use of Typha spp. for the phytotreatment of water contaminated with ibuprofen

Several studies on phytotoxic effects caused by organic xenobiotics and their removal from water by macrophytes have already been performed to evaluate the usefulness of these plants for phytoremediation technologies. In this context, a study was conducted to assess Typha spp.’s ability to withstand and remove, from water, the non-steroidal anti-inflammatory drug ibuprofen. For an initial ibuprofen concentration of 20 mgL 1, Typha removed nearly 60% of it within the first 24 h, attaining over 99% removal by the end of the assay (21 days). Exposure to higher ibuprofen concentrations did affect Typha’s growth but, by the end of the assays, plants’ growth as well as photosynthetic pigments approached normal values. An alteration in antioxidant enzymes activities (superoxide dismutase, catalase, guaiacol peroxidase) indicated that both roots and leaves were affected by the xenobiotic. Eventually, Typha seemed able to cope with ibuprofen’s induced oxidative damage suggesting its ability for phytotreatment of waters contaminated with ibuprofen