Abstract Textile sludge is a waste from the effluent treatment of textile laundries and its incorporation into alternative materials has been proposed as a possibility for its disposal. A systematic search was carried out in literature from this perspective, aiming to observe concentrations of waste material and its preparation, matrices used, technological performance and immobilization of textile waste. The matrices used were mortars, concretes and ceramic bricks, in general, deleterious effects were observed on mechanical characteristics of the materials produced. In concrete and mortars, the fineness had an impact on increase in water demand, which increased mixtures porosity; and organic matter and heavy metals, in cement hydration. Recent studies therefore proposed waste material pre-treatment as a favorable alternative. Increases in porosity also occurred in ceramic bricks, however, due to high organic matter content. Regarding waste immobilization, cementitious materials showed satisfactory performance; ceramic bricks, on the other hand, obtained some results outside the normative limits. Therefore, it is necessary to expand discussions regarding the pre-treatment carried out on textile sludge, as well as its impacts on mechanical and environmental performance.

Resumo Olodo têxtil é um resíduo do tratamento do efluente das lavanderias têxteis e sua incorporação em materiais alternativos tem sido proposta como possibilidade para sua destinação. Foi realizada uma busca sistemática na literatura nesta perspectiva, visando observar as concentrações de material residual e seu preparo, as matrizes utilizadas, o desempenho tecnológico e imobilização do resíduo têxtil. As matrizes empregadas foram argamassas, concretos e tijolos cerâmicos, sendo observados, de maneira geral, efeitos deletérios nas características mecânicas dos materiais produzidos. Em concretos e argamassas, a finura impactou no aumento da demanda de água, o que elevou a porosidade das misturas; e a matéria orgânica e metais pesados, na hidratação do cimento. Estudos recentes propuseram, então, o pré-tratamento do material residual como uma alternativa favorável. Incrementos na porosidade também ocorreram nos tijolos cerâmicos, porém, devido ao elevado teor de matéria orgânica. Quanto a imobilização do resíduo, os materiais cimentícios apresentaram desempenho satisfatório; já os tijolos cerâmicos, obtiveram alguns resultados fora dos limites normativos. Portanto, é necessário ampliar as discussões quanto ao pré-tratamento realizado no lodo têxtil, bem como seus impactos no desempenho mecânico e ambiental.

Abstract The aim of the present study was to assess the agronomic performance and chemical composition of soil cultivated with palisade grass (Urochloa brizantha cv. Marandu) subjected to growing doses of liquid blood waste. The experiment followed the completely randomized blocks design with six treatments and four repetitions. The following doses of processed liquid blood waste were applied to test palisade grass’ yield: 0, 150, 300, 450 and 600 m3 ha-1. In addition, it was used in conjunction with chemical fertilization at a rate of 50 kg ha-1 of P2O5 and 100 kg ha-1 of N (this treatment was not managed with liquid blood residue). Palisade grass forage yield was influenced by the fertilization strategy (P<0.001) - the highest values observed for this variable were recorded under blood waste doses of 450 m3 ha-1 and 600 m3 ha-1. The 0.0 - 0.20 m soil layer affect the organic matter fraction. On the other hand, phosphorus (P) content presented differences between fertilization strategies; thus, it was possible observing that the waste dose of 450 m3 ha-1 accounted for the highest availability of nutrients. The application of blood liquid waste as alternative source of organic fertilizers can be feasible, because it promotes significant increase in forage mass.

Resumen El objetivo fue evaluar el comportamiento agronómico y la composición química de suelos cultivados con pasto insurgente (Urochloa brizantha cv. Marandu) sometido a dosis crecientes de residuos sanguíneos líquidos. El experimento siguió el diseño de bloques completamente al azar con seis tratamientos y cuatro repeticiones. Las siguientes dosis de residuos sanguíneos líquidos procesados se aplicaron para analizar el rendimiento del pasto insurgente: 0, 150, 300, 450 y 600 m3 ha-1. Además, se utilizó en conjunto con la fertilización química a razón de 50 kg ha-1 de P2O5 y 100 kg ha-1 de N (este tratamiento no se manejó con residuos sanguíneos líquidos). El rendimiento de forraje de pasto insurgente estuvo influenciado por la estrategia de fertilización (P<0.001) - los valores más altos observados para esta variable se registraron bajo dosis de residuos sanguíneos de 450 m3 ha-1 y 600 m3 ha-1. La capa de suelo de 0.0 a 0.20 m afecta a la fracción de materia orgánica. Por otro lado, el contenido de fósforo (P) presentó diferencias entre las estrategias de fertilización; así, fue posible observar que la dosis de residuos de 450 m3 ha-1 resultó en la mayor disponibilidad de nutrientes. La aplicación de residuos sanguíneos líquidos como fuente alternativa de fertilizantes orgánicos puede ser factible, ya que promueve un aumento significativo de la masa forrajera.

ABSTRACT Municipal biowaste has a high potential for agricultural use. However, it requires an additional amendment to increase the nutritional content used during the composting process. The purpose of this study was to investigate the selection of compost-enhancing amendments from municipal biowaste using bibliometric and multicriteria analysis. The municipality of Yopal (Casanare, Colombia) was chosen as a case study. Using a search equation in the Scopus and Web of Science databases over five years (2018-2022), 53 publications were discovered, from which 25 were chosen for a full review to identify alternatives for amendment. Ashes, rice husks, sawdust, sugarcane bagasse, tree pruning waste, and alfalfa hay were assessed as amendment substitutes. Criteria such as financial cost, accessibility to acquire the amendment, nitrogen, phosphorus, and carbon contribution were used in the analysis of hierarchical processes. Tree pruning waste was the best option based on the criteria chosen because it is easily accessible and contributes with carbon and nitrogen (C/N: 13) to composting. Factors such as cost and affordability influence the physical and chemical characteristics that an amendment brings to the composting of municipal biowaste.

RESUMO Os biorresíduos municipais têm um elevado potencial para utilização agrícola. No entanto, requer uma alteração adicional para aumentar o conteúdo nutricional utilizado durante o processo de compostagem. O objetivo deste estudo foi investigar a seleção de aditivos melhoradores de compostagem a partir de resíduos biológicos municipais, utilizando análise bibliométrica e multicritério. O município de Yopal (Casanare, Colômbia) foi escolhido como estudo de caso. Utilizando uma equação de busca nas bases de dados Scopus e Web of Science ao longo de cinco anos (2018-2022), foram descobertas 53 publicações, das quais 25 foram escolhidas para uma revisão completa para identificar alternativas de alteração. Cinzas, cascas de arroz, serragem, bagaço de cana-de-açúcar, podas de árvores e feno de alfafa foram testados como substitutos de emendas. Critérios como custo financeiro, acessibilidade para aquisição do aditivo, aporte de nitrogênio, fósforo e carbono foram utilizados na análise dos processos hierárquicos. A poda de árvores foi a melhor opção pelos critérios escolhidos por ser de fácil acesso e contribuir com carbono e nitrogênio (C/N: 13) para a compostagem. Fatores como custo e acessibilidade influenciam as características físicas e químicas que uma alteração traz para a compostagem de biorresíduos municipais.

ABSTRACT: Persistent organic pollutants (POPs) represent a significant environmental problem due to their toxicity, with a high capacity to persist in the environment, resistance to conventional degradation methods, the ability to accumulate in living organisms and their magnification in food chains or food. In this review article, the impacts on health and environmental components are examined. Strategies and measures for control, mitigation and/or minimization of POPs are also addressed. Agricultural and industrial activities, inadequate final disposal of solid waste and lack of wastewater treatment are identified as the main sources of POP emissions. In addition, innovative and promising technologies are analyzed, such as nanotechnology, bioremediation, rhizoremediation, biochar, chromatography techniques, ultrasound, among others, for the adequate treatment of POPs. The review highlights both the advantages and limitations of these technologies, pointing out areas that still require developments to achieve effective treatments. More economical and ecological alternatives are also mentioned to counteract the impacts of POPs.

RESUMEN: Los contaminantes orgánicos persistentes (COP) representan un problema ambiental significativo debido a su toxicidad, con una alta capacidad para persistir en el entorno, resistencia a los métodos de degradación convencionales, la capacidad de acumulación en organismos vivos y su magnificación en las cadenas tróficas o alimentarias. En este artículo de revisión, se examinan los impactos en la salud y en los componentes medio ambientales. También se abordan las estrategias y medidas de control, mitigación y/o minimización de los COP. Se identifica a las actividades agrícolas, industriales, la inadecuada disposición final de los residuos sólidos y la falta de tratamiento de las aguas residuales como las principales fuentes de emisión de COP. Además, se analizan tecnologías innovadoras y prometedoras, como la nanotecnología, biorremediación, rizorremediación, biocarbón, técnicas de cromatografía, ultrasonido, entre otras, para el tratamiento adecuado de los COP. La revisión destaca tanto las ventajas como las limitaciones de estas tecnologías, señalando áreas que aún requieren desarrollos para lograr tratamientos eficaces. También se mencionan alternativas más económicas y ecológicas, para contrarrestar los impactos de los COP.

Resumo A tilápia tem tolerância a altas temperaturas, pode se reproduzir em cativeiro, crescer rápido e tem excelente custo-benefício. Por essas características, esta espécie é de grande interesse na aquicultura e, atualmente, o pescado mais produzido no Brasil. No entanto, com o aumento da produção de tilápias, houve também um aumento na quantidade de resíduos orgânicos, principalmente da filetagem, que descarta 70% dos resíduos. Existem muitos estudos sobre a extração de colágeno da pele de tilápia como alternativa para reduzir esses resíduos e agregar valor comercial. Neste trabalho, a extração do concentrado protéico foi testada utilizando um protocolo ácido, no qual as peles de tilápia foram submetidas a um pré-tratamento em meio ácido e precipitação salina, com variações de tempo e concentração. Após sua extração, a pele foi avaliada quanto a cinzas, umidade, proteína, solubilidade e pH. O concentrado protéico obtido apresentou baixos teores de cinzas, e a umidade está dentro dos apresentados pela literatura. O concentrado protéico apresentou teores de 68,73 a 80,58% de proteína e uma baixa solubilidade entre 4,03 a 6,93%. Em conclusão, a extração ácida é um possível meio de extração de colágeno, e a pele de tilápia é uma boa alternativa para reaproveitar os resíduos gerados na indústria de pescados.

Abstract Tilapia has high-temperature tolerance, can breed in captivity, grow fast, and have excellent cost-benefit. Because of these characteristics, this species is of great interest in aquaculture and, currently, the most produced fish in Brazil. However, by increasing tilapia production, there was also a rise in the amount of organic waste, mainly from filleting, which discards 70% of waste. There are many studies on collagen extraction from tilapia skin as an alternative to reduce these residues and add commercial value. In this work, the extraction of protein concentrate was tested using an acid protocol, in which the tilapia skins underwent a pre-treatment in an acid medium and saline precipitation, with variations in time and concentration. After its extraction, the skin was evaluated for ash, moisture, protein, solubility, and pH. The protein concentrate obtained showed low ash contents, and the humidity is within those presented by the literature. The protein concentrate showed levels from 68.73 to 80.58% of protein and a low solubility between 4.03 to 6.93%. In conclusion, acid extraction is a possible means of collagen extraction, and tilapia skin is a good alternative to reuse waste generated in the fish industry.

Abstract The development potential of byproducts from wastes of grape processing can be a promising alternative due to environmental questions. Moreover, there is the possibility of using this material in the development of products with added value. In this study, the wastes of grape skin (GSk), grape seed (GSe), and defatted grape seed with skin fragments (DGS) from ‘Ives noir’ grape (Vitis labrusca L.), grown under organic farming conditions, had their chemical composition and physical-chemical properties evaluated. Parameters of chemical composition, contents of phenolic compounds, total anthocyanins, flavonoids, and minerals, the antioxidant capacity, and water sorption capacity were evaluated. The wastes of grape were also analyzed by FTIR and TG/DTG. All residues had a high fiber content (54.1 - 74.3 wt.%), the DGS waste had the highest contents of phenolic compounds as flavonoids, and the GSk waste had the highest content of total anthocyanins. Antioxidant capacity values were higher in the ABTS+ method, with no statistical difference. On the other hand, in the DPPH antioxidant assay, the DGS and GSe wastes had higher antioxidant activity; these wastes also had greater thermal stability. The GSk waste had the highest water sorption capacity. The results show that the wastes from grape processing have the potential to be reused in applications with more value added.

ABSTRACT: Feathers are by-products that are generated in significant quantities by the poultry industry. Microbial bioconversion has been investigated as a promising strategy for the processing of feathers, since, along with the degradation of these keratinous materials, bioprocessing can result in value-added products. Thus, from the perspective of industrial microbiology, chicken feathers can be considered a raw material for obtaining microbial proteases. Within this context, this research investigated and characterized the production of extracellular proteases by Aspergillus sp., isolated from soil of the Amazon Rainforest. The enzymatic production was evaluated using several growth substrates (whole feathers, feather meal, human hair, casein, gelatin, peptone and chicken beaks). With highest enzyme production was obtained the feather meal (FM) and peptone. After 48 h of fermentation, FM degradation was 15.82%. The crude protease showed optimal activity at pH 5.0 and 37 °C and enzymatic activity was enhanced with the addition of 1 and 5 mM of CaCl2, MnSO4, KCl, MgSO4 and CuSO4. The detergents Tween 20 and Triton x-100, at concentrations 0.5 and 1% (v/v), tended to stimulate activity. The presence of 0.5 and 1% (v/v) of organic solvents (methanol, acetone, butanol, acetonitrile, isopropanol and DMSO), maintained the enzymatic activity. β-mercaptoethanolstimulated proteolytic activity in the enzymatic assays. This study suggested new direction for waste management with industrial applications giving rise to green technology for sustainable development.

RESUMO: As penas são subprodutos que são gerados em quantidades significativas pela indústria avícola. A bioconversão microbiana tem sido investigada como uma estratégia promissora para o processamento de penas, uma vez que, juntamente com a degradação desses materiais queratinosos, o bioprocessamento pode resultar em produtos de valor agregado. Assim, do ponto de vista da microbiologia industrial, as penas de frango podem ser consideradas matéria-prima para a obtenção de proteases microbianas. Dentro deste contexto, o objetivo deste trabalho foi investigar e caracterizar a produção de proteases extracelulares por Aspergillus sp., isolados de solo da floresta Amazônica. A produção enzimática foi avaliada utilizando diversos substratos de crescimento (penas inteiras, farinha de penas, cabelo humano, caseína, gelatina, peptona e bicos de frango). Com maior produção de enzima foi obtida a farinha de penas (FP) e peptona. Após 48 h de fermentação, a degradação da FP foi de 15.82%. A protease bruta mostrou atividade ótima em pH 5.0 e 37 0C e a atividade enzimática foi aumentada com a adição de 1 e 5 mM de CaCl2, MnSO4, KCl, MgSO4 e CuSO4. Os detergentes Tween 20 e Triton x-100, nas concentrações 0.5 e 1% (v/v), tenderam a estimular a atividade. A presença de 0.5 e 1% (v/v) dos solventes orgânicos (metanol, acetona, butanol, acetonitrila, isopropanol e DMSO), mantiveram a atividade enzimática. O β-mercaptoetanol estimulou a atividade proteolítica nos ensaios enzimáticos. Este estudo sugere uma nova direção para a gestão de resíduos com aplicações industriais dando origem à tecnologia verde para o desenvolvimento sustentável.

ABSTRACT The work was intended to evaluate the effect of different organic compounds originating from the mixture of agroindustrial and urban wastes, as well as their doses in the physiology and production of cowpea. The experiment was conducted under a randomized block design, in a 4 x 5 + 2 factorial arrangement, with four organic fertilizers (3 composed obtained from of sewage sludge, green coconut shell, carnauba butt; and sewage sludge biochar), five doses (20, 40, 60, 80 and 100 t ha-1) and two additional treatments (without fertilization and mineral fertilization). We evaluated the leaf gas exchange in three phenological stages and the productive aspects. Regarding the physiological variables, the compounds with carnauba butt and green coconut shell promoted the best results and throughout the crop cycle, the gas exchange decreased. The productive aspects were increased by about 60%, especially due to the treatments with organic compounds. The PCA can confirm the univariate results, with emphasis on compounds with green coconut shell and carnauba butt. The high percentage of explanation found in axis 1 (60.49%) may be associated with the fact that the gas exchange and production variables are highly responsive to fertilization. The treatment with biochar caused a reduction in both in the physiological and in the productive aspects. The compounds with carnauba tip and green coconut shell promote satisfactory results, being viable alternatives to complement chemical fertilization with an indicated dose of 300g pot-1 or 60 t ha-1.

Leachate from a composting plant was characterized and applied as a biofertilizer in lettuce crops. Characteristics of untreated (UE) and anaerobically treated (TE) leachate samples were compared. The pH of TE (8.2) increased in relation to the UE (5.2) due to an increase in ammonia nitrogen in TE (1197 mg L-1) compared to UE (859 mg L-1). Anaerobic treatment was efficient in the removal of organic matter from the leachate, evaluated by the decrease of dissolved organic carbon, biochemical oxygen demand, total organic carbon and total solids. K presented the highest concentration (1743 mg L-1) in TE, followed by Mg (135 mg L-1). Cd, Pb and Cr were present at low concentrations in the samples, 0.047, 0.206 and 0.081 mg L-1, respectively. Salmonella, thermotolerant coliforms and viable helminth eggs were not present in TE, which was applied as a biofertilizer in a lettuce crop and compared to mineral fertilization based on fresh matter and dry matter production. Lettuce production using TE was statistically equivalent to mineral fertilization. Toxic metals were not detected in the lettuce shoots. It was concluded that the anaerobically treated leachate from the composting company has the potential to be used as a biofertilizer.

Resumen Las tasas de crecimiento y urbanización de las ciudades pronostican el aumento de residuos. En los países en desarrollo la fracción orgánica representa aproximadamente la mitad del total de residuos generados; esta fracción genera lixiviados, gases tóxicos y la aparición de vectores. El compostaje es la alternativa más sencilla y económica para la recuperación de los residuos orgánicos. En este estudio se evaluó la calidad de dos compost elaborados con residuos orgánicos (CRO) y heces de mascota (CM). La pregunta de investigación analizó el efecto de estos abonos en la germinación y crecimiento de hortalizas seleccionadas. Se determinaron los principales parámetros de calidad y se diseñaron tratamientos con diferentes mezclas de CRO y CM. Los abonos evaluados se encuentran en su mayoría dentro de los parámetros de calidad. El porcentaje de germinación del CRO (18 %) y del CM (10 %) fue menor al requerido (80 %); y el CM excedió (1100 NMP/g) el máximo recomendado de coliformes totales (1000 NMP/g). La germinación fue mayor CRO y CM al 25 % (84 % en ambos casos). En los ensayos de crecimiento el control finalizó con mayor altura (13.88 cm), seguido del CRO al 10 % (13.22 cm) y CM al 25 % (11.50cm). Los resultados demuestran el potencial de los residuos orgánicos urbanos, incluyendo los desechos de mascotas, para el compostaje y sus efectos beneficiosos en el crecimiento de las plantas.

Abstract The rates of urban growth and urbanization indicate a projected increase in waste generation. In developing countries, the organic fraction constitutes approximately half of the total waste, leading to the production of leachate, toxic gases, and the emergence of vectors. Composting emerges as a straightforward and cost-effective solution for organic waste recovery. This study focused on evaluating the quality of compost derived from organic waste (CRO) and pet feces (CM). The research aimed to investigate the impact of these composts on the germination and growth of selected vegetables. The primary quality parameters were assessed, and different mixtures of CRO and CM were implemented as experimental treatments. The majority of the fertilizers examined complied with the quality standards. However, the germination percentage of CRO (18 %) and CM (10 %) fell below the required threshold (80 %), and CM surpassed the recommended maximum level of total coliforms (1100 NMP/g compared to the recommended 1000 NMP/g). Notably, a higher germination percentage (84 %) was observed for both CRO and CM at a 25 % compost addition. In terms of growth trials, the control group exhibited the tallest plants (13.88 cm), followed by the 10 % CRO treatment (13.22 cm) and the 25 % CM treatment (11.50 cm). The findings underscore the potential of urban organic waste, including pet waste, for composting and its positive impact on plant growth.

Summary: A retrospective-prospective research was carried out to establish a soil quality index (SQI) of Los Rios region (RR), Tabasco, Mexico, and its modeling with the near infrared technology (NIR) and chemometrics. The SQI was determined with the OM / (clay + silt) relationship to evaluate the Cambisol soils of RR. The OM percentage and the SQI were compared to define the best soil quality qualifier. Based on the SQI, 58% of the soils in RR exhibit degradation, while only 14% indicates a low concentration of OM. Therefore, we conclude that the SQI is more sensitive to quantify soil degradation compared to the evaluation based on OM. A sustainable soil management program and soil practices adapted to local environmental, social and economic conditions are recommended to increase OM and improve SQI. With the SQI, a classification model was established using near-infrared spectroscopy and chemometrics. The spectra of each soil sample were recorded and through chemometric interpretation, it was shown that it is possible to conduct a partial least squares discriminant analysis model (PLS-DA) to predict the SQI. The model meets all statistical qualifiers and correctly predicts the SQI in 100% of cases. We conclude that the NIR technology provides sufficient information to predict the SQI with the advantage of eliminating the consumption of reagents, no laboratory waste is generated, the analysis time is reduced to minutes, and the sample under study is not destroyed. In addition, the procedure is simple as it consists of drying, grinding and sieving the soil samples to assess the structural quality of the soil.

Resumen: Se realizó una investigación retrospectiva - prospectiva, para establecer un índice de calidad de los suelos (ICS) de la región de los Ríos (RR) en Tabasco, México y su modelación con la tecnología de infrarrojo cercano (NIR) y la quimiometría. Con la relación MO / (arcilla + limo) se estableció el ICS para evaluar los suelos Cambisoles de la RR. El porcentaje de MO y el ICS fueron comparados para definir el mejor calificador de la calidad de los suelos. Con base en el ICS, el 58% de los suelos de la RR presentan degradación, mientras que, solo el 14% de los suelos indican que presentan baja concentración de MO. Por lo que se concluye que el ICS es más sensible para cuantificar la degradación de los suelos cuando se comparó con la evaluación basada en la MO. Se recomienda un programa de manejo sostenible del suelo y prácticas edafológicas adaptadas a las condiciones locales, ambientales, sociales y económicas, para incrementar la MO y mejorar el ICS. Con el ICS se estableció un modelo de clasificación mediante espectroscopía de infrarrojo cercano y quimiometría. Se registraron los espectros de cada muestra de suelo y mediante interpretación quimiométrica se demostró que es posible establecer un modelo de análisis discriminante por mínimos cuadrados parciales (PLS-DA) para predecir el ICS. El modelo cumple con todos los calificadores estadísticos y predice correctamente el ICS en el 100% de los casos. Se concluye que la tecnología NIR genera información suficiente para predecir el ICS; con la ventaja de, eliminar el consumo de reactivos, no se generan residuos de laboratorio, se reduce el tiempo de análisis a minutos y no se destruye la muestra en estudio. Y solo se necesita secar, moler y tamizar las muestras de suelos para evaluar la calidad estructural de suelos.

Abstract Introduction. Composting transforms residual organic materials into a product with the potential to restore organic matter and nutrients for agriculture, while reducing the volume and weight of these materials and their disposal in landfills or as pollutants in rivers and aquifers. Objective. To optimize the commercial production of compost, with the improvement of the process conditions and the addition of microbial inoculum. Materials and methods. On an agro-industrial substrate, conditions such as aeration, temperature, pile height and humidity were optimized on the composting process, and the addition of 3 microbial inoculum degrading organic matter was evaluated, in order to compare them with a commercial and an absolute control. Chemical and microbiological analyzes were carried out, as well as innocuity, stability and maturity. In total, 17 chemical, 7 microbiological, 2 safety and 13 maturity variables were evaluated. For the analysis and comparison of the treatments, a multicriteria method was used to summarize the result of the 39 variables studied in a single representative value. Results. Two confidence intervals were established, the first (a) includes the commercial and the absolute control, with the lowest quality scores. The second (b) encompasses the microbiological treatments Degradabiol, Bacilos and Agrecicla, with the highest weighted values, and the best quality characteristics. Conclusion. The addition of inoculum, as well as humidity and temperature management, frequent turning, and row height, allowed to obtain better quality characteristics, compared to conventionally produced compost. Poor C/N ratio of initial raw materials was a factor that could not be corrected due to the type of waste usually processed. Viable measures need to be implemented in order to improve this relationship, which is generally deficient in commercial compost productions.

Resumen Introducción.El compostaje transforma materiales orgánicos residuales en un producto con potencial para restituir materia orgánica y nutrientes para la agricultura, mientras se reduce el volumen y peso de estos materiales y su disposición en rellenos sanitarios o como contaminantes de ríos y mantos acuíferos. Objetivo. Optimizar la producción comercial de compost, con la mejora de las condiciones del proceso y la adición de inóculos microbianos. Materiales y métodos. Sobre un sustrato agroindustrial se optimizaron condiciones del proceso de compostaje, tales como aeración, temperatura, altura de la pila y humedad, y se evaluó la adición de 3 inóculos microbianos degradadores de materia orgánica, para compararlos con un testigo comercial y un testigo absoluto. Se realizaron análisis químicos y microbiológicos, así como de inocuidad, estabilidad y madurez. En total se evaluaron 17 variables químicas, 7 microbiológicas, 2 de inocuidad y 13 de madurez. Para el análisis y comparación de los tratamientos se empleó un método multicriterio y de esa forma resumir el resultado de las 39 variables estudiadas en un solo valor representativo. Resultados. Se establecieron 2 intervalos de confianza, el primero (a) incluye al testigo comercial y al testigo absoluto, con las menores calificaciones de calidad. El segundo (b) abarca a los tratamientos microbiológicos Degradabiol, Bacilos y Agrecicla, con los mayores índices ponderados y las mejores características de calidad. Conclusión. La adición de inóculos, así como el manejo de la humedad, temperatura, volteos frecuentes y altura de hileras, permitió obtener mejores características de calidad, en comparación con el compost producido convencionalmente. La relación C/N deficiente de las materias primas iniciales fue un factor que no pudo ser corregido debido al tipo de residuos usualmente procesados. Es necesario implementar medidas viables para mejorar esta relación, que generalmente es deficiente en las producciones comerciales de compost.

Abstract. The transformation of agricultural waste into activated carbon represents an attractive approach as new and alternative source, but also as a reduction of pollution associated to the degradation of precursors. The organic residues sugarcane (Saccharum officinarum) bagasse-shell, orange (Citrus sinensis) peel-bagasse, and eucalyptus (Eucalyptus globulus) leaves, obtained from a biodrying process were transformed into activated carbons using phosphoric acid as activating agent. The resulting materials were physicochemically characterized and after that, carbonaceous electrodes were prepared to test the feasibility of using them in a discoloration electro-Fenton wastewater treatment process. Orange peel-bagasse biodried precursor transformed into activated carbon showed the highest efficiency when used as the modifier in a carbon paste electrode due to its highest porosity, electroactive area (24.9x10-2 cm2), and roughness (1.21 a.u.), also to its chemical affinity for anionic molecules. These properties, in addition to the capability of electro-sorb iron ions on the surface during the Fenton reaction, allowed a 44 % methyl orange discoloration efficiency. Sugarcane bagasse-peel and eucalyptus leaves biodried residues were also evaluated with efficiencies under 30 %, mainly attributed to intrinsic composition of the precursor materials.

Resumen. La transformación de los residuos agrícolas en carbón activado representa un enfoque atractivo y novedoso, además de que representa una alternativa a la reducción de la contaminación asociada a la degradación de residuos orgánicos. Los residuos orgánicos de bagazo de caña de azúcar (Saccharum officinarum), bagazo y cáscara de naranja (Citrus sinensis), y hojas de eucalipto (Eucalyptus globulus), que fueron obtenidos de un proceso de biosecado, se transformaron en carbón activado utilizando ácido fosfórico como agente activante. Los materiales resultantes se caracterizaron fisicoquímicamente y después de eso, se prepararon electrodos de pasta de carbón modificados con estos materiales, para estudiar la viabilidad de utilizarlos en un proceso de tratamiento de aguas residualesmediante electro-Fenton. El precursor biosecado de bagazo y cáscara de naranja transformado en carbón activado mostró la mayor eficiencia cuando se usó como modificador en un electrodo de pasta de carbón, debido a su mayor porosidad, área electroactiva (24.9x10-2 cm2) y rugosidad (1.21), también debido a su mayor afinidad química por moléculas aniónicas. Estas propiedades, aunadas a la capacidad de electro-sorber iones de hierro en la superficie durante la reacción de Fenton, permitieron una eficiencia de decoloración del naranja de metilo del 44 %. También se evaluaron residuos biosecados de bagazo de caña de azúcar y hojas de eucalipto, con eficiencias inferiores al 30 %, atribuidas principalmente a la composición intrínseca de los materiales precursores.

Abstract: In this paper, the Carbon/Nitrogen ratio was estimated by classifying the urban organic waste (UOW) based on qualitative (color and maturity) and quantitative (weight) characteristics via convolutional neural networks (CNN) and image processing. The reuse of UOW is a suitable process in waste management, preventing its disposition in landfills and reducing the effects on the environment and human health. Ambient conditions affect the UOW characteristics over time. Knowing these changes is essential to reuse them appropriately, mainly both carbon and nitrogen content. A categorization associated with the decomposition stage of the UOW was proposed, which becomes the corresponding UOW classes. Three convolutional neural network models were trained with UOW images. Two pre-trained CNN (MobileNet and VGG16) were trained by transfer learning technique, and one proposed model (UOWNet) was trained from scratch. The UOWNet model presented a good agreement for the classification task. The results show that this preprocess is a practical tool for assessing the Carbon/Nitrogen ratio of UOW from its qualitative and quantitative features through image analysis. It is a preliminary framework aimed to support household organic waste recycling and community sustainability.

Resumen El estudio del proceso de mineralización de bagazos y compostas de bagazo (subproductos procedentes de la elaboración del tequila) permite predecir los efectos que tendrán sobre la fertilidad del suelo al ser incorporados al mismo. El objetivo del estudio fue evaluar el proceso de mineralización del carbono orgánico remanente (COR); nitrógeno remanente (NR); y relación carbono/nitrógeno (C/N), de cuatro materiales Bagazo autoclave (BA), Bagazo difusor (BD), composta de bagazo autoclave (CBA) y Composta de bagazo difusor (CBD), en suelos contrastantes (regosol y luvisol), por el método de las bolsas de descomposición. Después de un año de evaluación las variables mostraron diferencias significativas entre los residuos orgánicos (RO); y suelos. Se encontró que la cantidad absoluta de COR disminuyó gradualmente en los bagazos a lo largo del año, mientras que la cantidad de NR no disminuyó de manera significativa, por lo que se observó una evidente reducción de la relación C/N. Estas variables en las compostas permanecieron parcialmente estables durante el proceso de mineralización. Por lo tanto, ambos materiales se pueden añadir al suelo, aunque con objetivos diferentes; en el caso de las compostas se pueden incorporar en el suelo, mientras que en el caso de los bagazos conviene sólo depositarlos sobre el suelo.

Abstract The study of the mineralization process of bagasse and bagasse compost (by-products from the production of tequila) allows predicting their effects on soil fertility upon their incorporation. The objective of the study was to evaluate the mineralization process of the remaining organic carbon (COR), N remaining nitrogen (NR) and Carbon/nitrogen ratio (C/N), in four materials autoclave bagasse (BA), diffuser bagasse (BD), autoclaved bagasse compost (CBA), and diffuser bagasse compost (CBD), in contrasting soils (regosol and luvisol), by the decomposition bag method. After one year of evaluation, the variables showed significant differences between organic waste (OR) and soils. It was found that the absolute amount of COR gradually decreased in the bagasse throughout the year, while the amount of NR did not decrease significantly, so, an evident C/N ratio reduction was observed. These variables in the composts remained partially stable during the mineralization process. Therefore, both materials can be added to the soil, but with different objectives; in the case of compost, they can be incorporated into the soil, while in the case of bagasse it is only advisable to deposit them over soil surface.