Unsteady state series CSTR modeling of removal of ammonia nitrogen from domestic wastewater treated in a vertical flow constructed wetland

This work shows simulation results for subsurface vertical flow constructed wetland (VFCW) using a series CSTR model. The VFCW considered received the outflow from a domestic wastewater treatment plant. In addition, it was planted with Cyperus sp. and filter media was unsaturated. The model was based on an unsteady state mass balance for ammonia, nitrites, and nitrates, using one to three series CSTRs. Nitrogen transformation mechanisms considered were ammonification, nitrification, plant uptake and denitrification. The following effects were evaluated: the number of reacting CSTRs from one to three; the occurrence of the reaction in second and third CSTRs for the case that three CSTRs hold; the use of either equal or different values of reaction rate parameters between CSTRs; and the discretization of the reaction rate parameters. The inflow and outflow measurements of ammonium, nitrites, and nitrates were used for model calibration. The estimated parameters included the reaction rate coefficients and reactor water volume. The coefficient of determination (R2) evidenced a satisfactory capability of simulating outlet pollutant concentrations. Two and three reacting CSTRs achieved similar R2 value (0.54-0.55), whereas one reacting CSTR achieved an R2 of 0.39, and three CSTRs with reaction only in the first tank achieved an R2 of 0.42. Discretization of the nitrification rate for the case of two reacting CSTRs led to an R2 of 0.94. The parameter sensitivity analysis revealed a significant effect of model parameters on the R2 value

Analysis of socio-environmental benefits from the implementation of cleaner production strategies in the agricultural sector of the middle reaches of the river chinchiná, colombia

The purpose of this paper is to assess the socio-environmental benefits generated by the implementation of cleaner production strategies in the agriculture and livestock sectors, in the middle part of the Chinchina river basin, Colombia. The methodology involves recording of field data on the basis of interviews and semi-structured dialogue; processing and analysis of data on the basis of matrix adaptation and network diagramming; and assessment of socio-environmental benefits, with determination of socio-environmental significance, based on adaptation of the Leopold methodology, using the parameters of magnitude and importance. The main results are: i) the cleaner production strategies implemented in the farms located in the study zone were identified and categorized into conservation, reduction or elimination strategies; ii ) the corresponding socio- environmental benefits were evaluated by determining primary, secondary and tertiary benefits related to both the benefits provided by ecosystems and the social benefits generated.En el sector agropecuario de la parte media de la cuenca del río Chinchiná, Colombia, en 2012 y 2013 se evaluaron los beneficios socio-ambientales generados por la implementación de estrategias de producción más limpia en el sector agropecuario. La metodología incluyó la recolección de datos de campo a partir de entrevistas y diálogos semi-estruturados, procesamiento y análisis de datos a partir de la adaptación de matrices y construcción de diagrama de redes, evaluación de los beneficios con determinación de la significancia socio-ambiental a través de la adaptación de la metodología de Leopold con el uso de parámetros de magnitud e importancia. Los resultados mostraron que, las estrategias para el estudio de producción más limpia implementadas en las fincas localizadas en la zona permitieron identificar y categorizar estrategias de conservación, reducción o eliminación, siendo posible evaluar los beneficios socio-ambientales correspondientes a partir de la determinación de los beneficios primarios, secundarios y terciarios relacio-nados tanto con los beneficios que prestan los ecosistemas como los sociales que se generan

On the mismatches between the monetary and social values of air purification in the colombian andean region: a case study

There is growing interest in air quality and air purification, due to current high pollution levels, their effects on human health, and implications for urban economies. Since the improvement of air quality carries important economic value, air-related benefits have been evaluated monetarily from two perspectives: the first relates to air quality improvements, while the second values air purification as an ecosystem function. This research opted for the second perspective, given that the study area (two Colombian municipalities) does not suffer from poor air quality conditions, but stakeholders prioritized this function as highly important to them. Contingent valuation methods were applied in order to identify the population’s probability of willingness to maintain the air purification function. Although individuals (n = 245) attribute a yearly monetary value of USD 1.5 million to air purification, it was found that, despite the high level of social importance that respondents assigned to air purification (mean = 4.7/5), this had no correlation with payment values (rho = 0.0134, p = 0.8350); that is, households do not really recognize the monetary value of all the benefits they receive or the benefits they would lose if the service suffers changes. Hence, it is posed that monetary values do not necessarily reflect the social importance that individuals assign to ecosystem services, and attention is called to the need to integrate social and monetary values into decision-making processes, so as to encompass the complexity of ecosystem services and conciliate conflicting valuation language

Status index of optimal water variables for biodiversity conservation in the Lagoon of Sonso in Colombia

In order to determine an index of the status of optimal water variables for biodiversity conservation in the Sonso Lagoon, the data obtained from 2004 to 2018 were used. To determine the index, a methodology based on a multivariate analysis of the physical-chemical water variables was used, as well as a correlation analysis for their delimitation. Subsequently, the definition of weights and the parameterization of the variables for the final construction of the index were made. As a result, it was found that the lagoon is in an adequate state with a value index of 0.65, with a highly vulnerable tendency to be in an acceptable state and go to a critical state, depending on the anthropic pressure it has. As a conclusion, it was obtained that variables such as dissolved oxygen, total phosphorus and electrical conductivity are determining factors in establishing the index

Convergence Assessment of the Trajectories of a Bioreaction System by Using Asymmetric Truncated Vertex Functions

In several open and closed-loop systems, the trajectories converge to a region instead of an equilibrium point. Identifying the convergence region and proving the asymptotic convergence upon arbitrarily large initial values of the state variables are regarded as important issues. In this work, the convergence of the trajectories of a biological process is determined and proved via truncated functions and Barbalat’s Lemma, while a simple and systematic procedure is provided. The state variables of the process asymptotically converge to a compact set instead of an equilibrium point, with asymmetrical bounds of the compact sets. This convergence is rigorously proved by using asymmetric forms with vertex truncation for each state variable and the Barbalat’s lemma. This includes the definition of the truncated V i functions and the arrangement of its time derivative in terms of truncated functions. The proposed truncated function is different from the common one as it accounts for the model nonlinearities and the asymmetry of the vanishment region. The convergence analysis is valid for arbitrarily large initial values of the state variables, and arbitrarily large size of the convergence regions. The positive invariant nature of the convergence regions is proved. Simulations confirm the findings

Análisis multitemporal de las coberturas vegetales en el área de influencia de las minas de oro ubicadas en la parte alta del sector de Maltería en Manizales, Colombia

Uno de los métodos utilizados para analizar impactos ambientales ocurridos a través del tiempo, es conocer la evolución de los ecosistemas mediante Sistemas de Información Geográfica-SIG; así que en este artículo, se presenta un análisis multitemporal de una zona con influencia de dos sistemas productivos principalmente: la ganadería y la minería y sobre la cual se presentan impactos ambientales significativos. La metodología partió de la utilización y digitalización de fotografías aéreas de los años 1998 y 2010 y una imagen tomada de Google Earth del año 2015 debidamente georreferenciada, se trabajó con una escala 1:25000; así mismo, se utilizó el programa ArcGIS para el procesamiento de la información. En el análisis se estableció como han sido las variaciones en las coberturas vegetales en el tiempo, la influencia de los sistemas productivos sobre las áreas boscosas, las áreas que han tenido procesos de recuperación y otras que con el tiempo han ido desapareciendo

Análisis multitemporal de las coberturas vegetales en el área de influencia de las minas de oro ubicadas en la parte alta del sector de Maltería en Manizales, Colombia

Uno de los métodos utilizados para analizar impactos ambientales ocurridos a través del tiempo, es conocer la evolución de los ecosistemas mediante Sistemas de Información Geográfica-SIG; así que en este artículo, se presenta un análisis multitemporal de una zona con influencia de dos sistemas productivos principalmente: la ganadería y la minería y sobre la cual se presentan impactos ambientales significativos. La metodología partió de la utilización y digitalización de fotografías aéreas de los años 1998 y 2010 y una imagen tomada de Google Earth del año 2015 debidamente georreferenciada, se trabajó con una escala 1:25000; así mismo, se utilizó el programa ArcGIS para el procesamiento de la información. En el análisis se estableció como han sido las variaciones en las coberturas vegetales en el tiempo, la influencia de los sistemas productivos sobre las áreas boscosas, las áreas que han tenido procesos de recuperación y otras que con el tiempo han ido desapareciendo.One of the methods used to analyze environmental impacts occurred over time, is to know the evolution of ecosystems using Geographic Information Systems-GIS; so in this article, it is presented a multitemporal analysis of an area with influence of two production systems mainly: livestock and mining, and on which there are significant environmental impacts. The methodology was based on the use and digitalization of aerial photographs of the years 1998 and 2010 and an image taken of Google Earth of the year 2015 properly georeferenced, was worked with a scale 1: 25000; Also, the ArcGIS program was used for information processing. The analysis established the variations in plant cover over time, the influence of productive systems on forested areas, areas that have had recovery processes and others that have disappeared over time

Temporary wetland evolution in the upper Chinchiná river basin and its relationship with ecosystem dynamics

A study was performed regarding high Andean wetland degradation in a paramo area between the municipalities of Villamaría and Manizales, Colombia, by way of multi-temporal analysis, using satellite images from optical sensors, such as LANDSAT and RAPIDEYE, as well as images from RADAR sensors (ALOS PALSAR, SENTINEL 1), and analysis of anthropic and natural factors. As a result, the wetlands have begun a significant, linear decline with 67.9% water mirror loss in a nine-year period. There is also a direct relationship between wetland loss, and decreases in precipitation, and anthropization processes. It was determined, from the anthropic factor analysis, that that livestock and agricultural land use are those which cause the greatest negative effect on wetland decline in the studied area

Recognizing, normalizing and articulating: an approach to highlight plural values of water ecosystem services in Colombia

The dialectical relationship between ecosystems and society is complex; therefore, holistic approaches are required to address this complexity. This view also stands out in the ecosystem services valuation field, where different scholars and global platforms have drawn attention to the need to incorporate plural valuation initiatives at decision-making. In this sense, through a comprehensive design, we conducted a multi-layered valuation of ecosystem services, and we highlighted multiple values in two areas of the province of Caldas, Colombia. We proposed a three-phase valuation process called Recognizing, Normalizing and Articulating values. Then, in cooperation with the regional environmental authority, we obtained different water-related ecosystem services values. Our results showed some warnings: first, we found mismatches between ecosystem services values; second, people assigned high values to ecosystems but the actual capacity of ecosystems to support ES is low. Finally, monetary values were marginal compared to social and ecological values. We conclude by saying that the more strata are assessed, the more values appear in the valuation scenarios, and those values could be conflicting. Our results have political implications, since they highlight the need to incorporate plural values as a fundamental tool for planning and land use in real scenarios where conflicts of interest and values are evident