Resumo: Objetivo Os eventos de inundação associados às planícies de inundação de muitos rios do mundo afetam a composição e estrutura da biota aquática, pois a variação do nível de água pode garantir a integridade ecológica das áreas úmidas associadas. O objetivo do presente é descrever a variação espacial e temporal na composição da assembleia de macrófitas aquáticas em uma área alagável em Santo Tomás durante um período de inundação no rio Magdalena (norte da Colômbia). Métodos Nós avaliamos a composição e abundância da comunidade de macrófitas aquáticas em três estações de coleta no rio Magdalena mensalmente durante 8 meses entre 2017 e 2018. Nós estimamos a variação espaço-temporal da comunidade usando o método Chao e a cobertura vegetal usando os testes de Kruskal-Wallis e U Mann-Whitney. Uma curva de abundância de classificação foi usada para a dominância das espécies entre os meses de amostragem e as estações. Uma escala não métrica multidimensional (nMDS) foi utilizada para analisar a distribuição espacial e temporal e a análise de correspondência canônica (CCA) foi realizada para estudar a relação entre a composição das espécies de macrófitas e as variáveis físico-químicas da água. Resultados Nos transectos foi registrado um total de 24 espécies de plantas aquáticas distribuídas em 23 gêneros e 15 famílias. A espécie mais abundante (% de cobertura vegetal) foi Ipomoea aquatica (19%), seguida por Ludwigia helminthorrhiza (14%) e Eichhornia azurea (13%). Espécies flutuantes e emergentes foram observadas com mais frequência. As mudanças espaço-temporais e os maiores valores de riqueza e cobertura de macrófitas aquáticas nas zonas úmidas de Santo Tomás ocorreram durante a estação das chuvas. As espécies mais dominantes foram L. helminthorrhiza, E. azurea, Pistia stratiotes, Neptunia oleracea, I. aquatica, Salvinia auriculata e Hymenachne amplexicaulis. A qualidade da água apresentou variações espaciais e temporais durante o pulso de inundação, e algumas variáveis como matéria orgânica (DOQ, DBO5), pH, profundidade, amônia e coliformes fecais foram relacionados à composição da comunidade de macrófitas. Conclusões Em suma nós concluímos que o pulso de inundação do rio Magdalena influenciou a composição das plantas aquáticas nas zonas úmidas de Santo Tomás.

Abstract: Aim The associated flood events to floodplain of many rivers in the world affect the composition and structure of aquatic biota due the water levels variation can ensure ecological integrity of associated wetlands. This study describes the spatial and temporal variation in the macrophyte assemblage in the Santo Tomás wetland during seasonally flood-pulsed of the Magdalena River (North of Colombia). Methods For eight months, between 2017 and 2018 samplings were carried out in three stations for composition and abundance of aquatic macrophytes. Spatio-temporal pattern of richness was estimated with Chao methodology and vegetation cover was calculated using Kruskal-Wallis and U Mann-Whitney tests. A range abundance curve was used for species dominance between samplings and stations. A non-metric multidimensional scaling (nMDS) was used to analyze the Spatio-temporal distribution, Canonical Correspondence Analysis (ACC) was performed to relate the physicochemical variables to the species composition. Results A total of 24 species of aquatic plants distributed in 23 genera and 15 families were registered in the transects. The most abundant species (% of vegetation cover) were Ipomoea aquatica (19%), followed by Ludwigia helminthorrhiza (14%) and Eichhornia azurea (13%). The most frequent life form was free-floating, followed by the emergent one. The Spatio-temporal changes and the highest values of richness and vegetation cover in the Santo Tomás wetlands occurred during the filling and high waters period. L. helminthorrhiza, E. azurea, Pistia stratiotes, Neptunia oleracea, I. aquatica, Salvinia auriculata, and Hymenachne amplexicaulis were the most dominant species. The quality water of Santo Tomás Wetlands showed spatial and temporal variations during flooding pulse and some physicochemical variables such as organic matter (COD, BOD5), pH, depth, ammonia, and fecal coliforms were related to macrophyte community composition Conclusions Spatial and temporal changes of aquatic plants in Santo Tomás wetlands were related to the flooding pulse of Magdalena River.

Abstract The sustainability issues related to food security and use of land, water and energy resources provide impetus to develop treatment technologies that are sensitive to these issues. To advance tropical studies, with an emphasis on sustainability, a small pilot-scale integrated wastewater treatment facility, was designed and built on a small farm in the Sierra Nevada de Santa Marta (Colombia). The system consists of a septic tank, followed in series, by 5 subsurface-flow wetlands, a single surface-flow wetland and a terminal storage lagoon. The efficiency of the pilot plant was studied over a three-year period to evaluate water quality dynamics as a function of hydraulic loading rate, elapsed time and vegetation management. The objective of this study (year II), was to evaluate the comparative efficacy of the treatment units, planted with tomatoes (Lycopersicum sculentum). The results revealed the 5-day biological oxygen demand (BOD5) and chemical oxygen demand (COD) removal efficiencies were above 41%, coliform bacteria removal was 46 -81%. No ammonium nitrogen (NH4+-N) removal (< 1%) and phosphorus removal PO4−3-P was of 10%. A relatively high production of tomatoes (730 g/m2) was obtained in comparison to a traditional crop in a tropical country. These preliminary results will aid in formulating technical design criteria and operational guidelines of constructed wetland technologies for treatment and reuse of domestic wastewater below tropical conditions.

Resumen Los temas de sostenibilidad relacionados con la seguridad alimentaria y el uso de los recursos como tierra, agua y energía, dan impulso al desarrollo de tecnologías de tratamiento sensibles a estos problemas. Para avanzar en los estudios tropicales, con énfasis en la sostenibilidad, se diseñó y construyó una pequeña instalación de tratamiento integrada de aguas residuales a escala piloto en una pequeña granja en la Sierra Nevada de Santa Marta (Colombia). El sistema consta de un tanque séptico, seguido en serie, por 5 humedales de flujo sub superficial, un humedal de flujo superficial y un estanque de almacenamiento final. La eficiencia de la planta piloto fue estudiada durante un período de tres años para evaluar la dinámica de la calidad del agua en función de la carga hidráulica, el tiempo transcurrido y el manejo de la vegetación. El objetivo de este estudio (año II), fue evaluar la eficacia comparativa de las unidades de tratamiento, plantadas con tomates (Lycopersicum sculentum). Los resultados revelaron que la eficiencia de la demanda biológica de oxígeno (DBO5) y la demanda química de oxígeno (DQO) fue superior a 41% y la eliminación de bacterias coliformes estuvo entre 46 y 81%. No hubo eliminación de nitrógeno amoniacal (NH4 + -N) (<1%) y la eliminación de fósforo (PO4-3-P) fue del 10%. Una producción, relativamente alta, de tomates (730 g / m2) fue obtenida en comparación con un cultivo tradicional en un país tropical. Estos resultados preliminares ayudarán a formular criterios técnicos de diseño y directrices operacionales de tecnologías de humedales construidas para el tratamiento y la reutilización de aguas residuales domésticas bajo condiciones tropicales.

Abstract: This study evaluated the removal efficiency of organic matter (COD), nitrogen (NH4 -, NO3 ~) orthophosphate and total and fecal coliforms in four horizontal subsurface flow pilot scale constructed wetlands using two species of local plants. Two systems were planted with Cyperus ligularis and two Echinochloa colonum. The experiment consisted of sedimentation tank of 760 L (primary treatment) from where water was poured, through PVC pipe to constructed wetlands system. Each wetland was filled with gravel of a diameter of 8 mm and porosity of 0.4. Once a day during four months, wetlands added a flow rate of 42 L.day-1 to maintain a hydraulic residence time of three days. Wastewater samples (influent and effluent) were collected three times by week for COD and nutrients concentrations. Once a week the fecal and total coliforms were analyzed. Removal efficiency of COD, ammonium, nitrate and orthophosphate were of 93%, 65%, 71% and 32% respectively for C. ligularis and of 85%, 54%, 67% and 57% respectively for E. colonum. Removal efficiency of total and fecal coliforms was on 99.9% for both species. The results indicated no significant difference (P < 0.05) in the removal of principals contaminants in the wetland planted C. ligularis indicating higher ability of this species for the treatment of domestic wastewater

Resumen: Este estudio evaluó la eficiencia de eliminación de materia orgánica (DQO), nitrógeno (NH4+, NO3 -) ortofosfatos, y coliformes totales y fecales en cuatro humedales construidos de flujo subsuperficial horizontal a escala piloto usando dos especies de plantas locales. Dos sistemas fueron plantados con Cyperus ligularis y dos con Echinochloa colonum. El experimento constó de un tanque de almacenamiento de 760 litros (tratamiento primario), desde donde se vertió el agua residual, mediante tubería de PVC, al sistema de humedales. Cada humedal fue rellenado con grava granítica de unos 8 mm de diámetro y porosidad de 0.4. Una vez al día y durante cuatro meses, se adicionó a los humedales un caudal de 42 l.día-1, para mantener un tiempo de residencia hidráulico de tres días. Las muestras de agua residual (afluente y efluente) se recolectaron tres veces por semana para determinar la concentración de DQO y nutrientes. Una vez por semana se determinó coliformes fecales y totales. La eliminación de DQO, amonio, nitrato y ortofosfatos fue de 93, 65, 71 y 32%, respectivamente, para C. ligularis, y de 85, 54, 67 y 57%, respectivamente, para E. colonum. La eficiencia de eliminación de bacterias coliformes fue de 99.9% para ambas especies. Los resultados indicaron que hubo una diferencia significativa (P < 0.05) en la eliminación de los principales contaminantes en el humedal plantado con C. ligularis, indicando una mayor capacidad de esta especie para el tratamiento del agua residual doméstica.

Abstract: Biological systems can be combined with advanced oxidation technologies (AOT) for wastewater treatment. It is essential to assess the usefulness of the combination of these technologies, by adjusting the designs and operating conditions. This research project approached the disinfection of domestic wastewater for reuse by evaluating the potential of the combination of a solar photocatalytic process using hydrogen peroxide (Solar UV/H2O2) with a horizontal subsurface flow constructed wetlands (HSSF CW) system as an alternative for reuse of domestic wastewater. To do this, a photoreactor consisting of polymethylmethacrylate (PMMA) pipes exposed to solar UV radiation was built, operating in batch mode, and the photolysis effect and the addition ofhydrogen peroxide were evaluated. Doses of 3, 30 and 300 mgl'1 of H2O2 were applied. Removal efficiency of Total and Fecal coliforms was evaluated considering the effect of ultraviolet radiation, the dose of hydrogen peroxide and treatment with HSSF CW planted with Cyperus ligularis. Results indicate that it is possible to obtain a 99.999% disinfection degree of total and fecal coliforms when AOT and the biological system are coupled with a retention time of 3 days in the HSSF CW and 5 hours for the photoreactor.

Resumen: La posibilidad de combinar sistemas biológicos con tecnologías avanzadas de oxidación (TAO) para el tratamiento de aguas residuales hace imprescindible valorar la utilidad de la combinación de tales tecnologías, ajustando los diseños y condiciones de operación. Este proyecto de investigación abordó la desinfección de agua residual doméstica con fines de reutilización, evaluando el potencial de combinación de un proceso fotocatalítico solar que utiliza peróxido de hidrógeno (UV solar/H2O2) con un sistema de humedales construidos de flujo subsuperficial horizontal (HC FSSH), como alternativa para el reúso del agua residual doméstica para riego. Para ello, se construyó un fotorreactor en tubos de polimetilmetacrilato (PMMA) expuesto a la radiación solar UV, que opera en modo batch, y se evaluó el efecto de la fotólisis y adición de peróxido de hidrógeno, aplicando dosis de 3, 30 y 300 mgl-1 de H2O2. La eficiencia de eliminación de coliformes totales y fecales fue evaluada considerando el efecto de radiación ultravioleta, dosis de peróxido de hidrógeno y tratamiento con HC FSSH plantados con Cyperus ligularis. Los resultados indicaron que es posible obtener un grado de desinfección de 99.999% de coliformes fecales y totales cuando se acoplan la TAO y el sistema biológico con un tiempo de retención de tres días en el HC FSSH y cinco horas en el fotorreactor.