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Abstract:In open pit coal mining, soil and vegetation are removed prior to the start of mining activities, causing physical, chemical, and microbiological changes to the soil and landscape. The present work shows the results of an integrated study of the remediation of mine waste with a high level of salt contamination in areas of the Cesar Department (Colombia), employing biochar as an amendment. Physical-chemical properties including Munsell color, texture, pH, electrical conductivity, water-holding capacity, cation exchange capacity, metal content, organic carbon, sulfates, extractable P, and total nitrogen were characterized both in the soils contaminated with mine residues and the biochar sample. A high concentration of sulfates, calcium, iron, and aluminum and a significant presence of Na, followed by minor amounts of Mg, K, Cu, and Mn, were observed in efflorescent salts. X-ray diffraction indicated a high presence of quartz and gypsum and the absence of pyrite and Schwertmannite in the efflorescent salt, while showing broad peaks belonging to graphene sheets in the biochar sample. Soil remediation was evaluated in Petri dish seed germination bioassays using Brachiaria decumbens. Biochar was shown to be effective in the improvement of pH, and positively influenced the germination percentage and root length of Brachiaria grass seeds.

RESUMENLos contaminantes orgánicos emergentes conforman un grupo de sustancias muy heterogéneas, cuya característica en común es que causan efectos negativos sobre los organismos acuáticos, por lo que deben de ser eliminados del ambiente. Lamentablemente, los procesos convencionales con los que operan las plantas de tratamiento de aguas residuales, especialmente los de tipo biológico, son ineficientes en la remoción de estas sustancias. Por este motivo, se hace necesaria la evaluación y optimización de tratamientos más eficaces, entre los que se encuentran los procesos de oxidación avanzada y de filtración por membranas. Sin embargo, ambas técnicas presentan inconvenientes que pueden limitar la aplicación individual de las mismas, de modo que podría proponerse la combinación de dichas tecnologías con procesos biológicos como mejor solución para tratar las aguas residuales contaminadas con contaminantes orgánicos emergentes.Palabras clave: contaminación acuática, biodegradación, procesos de oxidación avanzada. Processos de tratamento de águas residuárias para a remoção de contaminantes orgânicos emergentes RESUMOOs contaminantes orgânicos emergentes formam um grupo de substâncias bastante heterogêneas cuja característica comum é que causam efeitos negativos em organismos aquáticos, por isso, devem ser removidas do meio. Lamentavelmente, os processos convencionais que operam nas plantas de tratamento de águas residuárias, principalmente do tipo biológico, são ineficientes na degradação destas substâncias. Por esta razão, é necessária a avaliação e a otimização dos tratamentos para torná-los mais eficientes, incluindo os processos oxidativos avançados e de filtração por membranas. No entanto, ambas as técnicas têm desvantagens que podem limitar a aplicação isolada delas, de modo que é proposta a combinação dessas tecnologias com processos biológicos como a melhor solução para o tratamento de águas residuárias contaminadas com contaminantes emergentes.Palavras-chave: poluição da água, biodegradação, processos oxidativos avançados.

Due to the harmful effects associated with the presence of microcystin-LR  (MC-LR) cyanotoxin, photo-degradation assays were performed in natural and distilled water using the combined action of ultraviolet (UV) radiation and hydrogen peroxide (H2O2). The effect of H2O2 content and UV irradiance was evaluated and optimized using a multilevel factorial design in distilled water spiked with 20 μg L-1 MC-LR. The coupled UV/H2O2 system under optimal operating conditions (0.63 mW cm-2 irradiance and 30 mg L-1 H2O2) was more effective than the individual action of UV irradiance or H2O2 content for 30 min of treatment time, since a reduction of 97.78% of MC-LR was achieved. After optimizing the operating conditions, they were applied for natural water, obtaining MC-LR removals similar to those achieved with distilled water (99.59 and 99.73%, respectively), reaching a final MC-LR concentration in both matrices well below the maximum recommended limit established by WHO for MC-LR in drinking water, fixed at 1 μg L-1. 15 mg L-1 of H2O2 were also tested, and although 98.08% of MC-LR elimination was found for a reaction time of 60 min, WHO advisable limit was not surpassed.  The UV/H2O2 process could be considered as an alternative to the conventional processes water facilities are operating with to tackle the problem of fresh water pollution with cyanotoxins, providing the accomplishment of the whole set of water quality standards included in the legislation.

Coffee is one of the most consumed beverages in the world and is crucial in the economy of many developing countries. The search to improve coffee quality comes from many fronts, as do the many ways to measure quality and the factors that affect it. Several techniques are used to measure the different metrics to assess coffee quality, across different types of coffee samples and species, and throughout the entire process from farm to cup. In this work, we conducted a systematic mapping study of 1,470 articles to identify the aspects of quality that are the most important in the scientific literature to evaluate coffee throughout the processing chain. The study revealed that cup quality and biochemical composition are the most researched quality attributes. The main objective of the reviewed studies is the correlation between different quality measurements. The most used techniques are the analytical chemistry methods. The most studied species is Coffea arabica. The most used sample presentation is green coffee. The postharvest stage is the most researched, in which quality control receives more attention. In the preharvest stage, management practices stand out. Finally, the most used type of research was the evaluation research.

The textile industry is a generator of high volumes of waste water with a high content of pollutants such as azo dyes, which are recalcitrant and persistent in the environment, these ones have been of interest in the last decades for the entities in charge of the care of the environment. This study evaluated the ability to discolor of reactive black 5 (NR5) by a consortium and the microorganisms that constitute Rhodotorula mucilaginosa, Galactomyces pseudocandidum and Escherichia coli free and immobilized in calcium alginate, coffee husks and bagasse of sugar cane. The results show discoloration was evidenced, where the highest percentage corresponds to G. pseudocandidum (90,05%) and the lowest to R. mucilaginosa (79,31%). When comparing the percentages of discoloration between the free microorganisms and the immobilization matrices, it is observed that the former exhibit the highest percentages of discoloration. In addition, there are no significant differences between using cane bagasse or coffee husks as immobilization matrix.

Aim This article deals with the estimation of a model for CO2 emissions in the Hidrosogamoso reservoir based on the organic matter level and water quality. This is in order to determine the impact of the creation of a tropical reservoir on the generation of greenhouse gases (GHG), and to establish the water quality and emissions dynamics. We hypothesize that the spatial variability of emissions is determined by water quality and carbon cycling in water. Methods Multivariate techniques were applied to determine the relationships between CO2 and certain physicochemical variables measured in the reservoir between February and May 2015, taking samples in 10 stations and measuring 14 variables (water quality parameters and CO2). Factor, cluster, discriminant and regression analysis, as well as the geostatistical technique kriging, were used. Results We observed that all variables except dissolved organic carbon have strong linear relationships. Nitrate, total-P, total solids and total suspended solids are related due to the presence of nutrients in the water; chlorophyll a and biodegradable dissolved organic carbon due to organic carbon; and alkalinity and dissolved solids due to dissolved minerals. The sampling stations can be classified into two homogeneous groups. The first consists of the stations peripheral to the reservoir and the second of stations inside the reservoir. This difference is due mainly to the behavior of chlorophyll a and biodegradable dissolved organic carbon, and these two variables are also the best predictors for CO2, with a maximum adjustment of 70%. Conclusions Our main conclusion is that the production of CO2 is due to decomposition of flooded organic carbon, depends on the soils flooded and the tributary water quality, and that the production of this gas will, based on the literature, continue for 5 to 10 years depending on the nature of the forest flooded.