EFFECT OF LIQUID SWINE WASTEWATER DOSES ON PHYSICAL, CHEMICAL AND ELECTROCHEMICAL ATTRIBUTES IN A CERRADO OXISOL. The addition of organic residues enhances soil and plant organic matter and nutrient content. To gauge the impact of varying liquid swine waste (LSW) levels on soil, we studied changes in a clayey Oxisol’s physical, chemical, and electrochemical traits from the Cerrado. LSW doses (0, 50, 150, 450, 600 m3 ha−1) were applied to the 0-0.20 m layer in a randomized design with three replicates. Post a 30-day incubation at 60% field capacity, the soil underwent mineralogical, physical (clay dispersed in water - CDW), chemical (sodium adsorption ratio - SAR, cation exchange capacity - CEC, base saturation - V%), and electrochemical (pH in H2O and KCl, ApH, point of zero charge - PZC, point of zero salt effect - PZSE, surface electric potential - iµo, and electrical conductivity - EC) analyses. The levels of exchangeable Ca, K, Mg, Na, and available P increased with increasing LSW doses. Increasing LSW doses in the soil led to an increase in EC, but soil salinization was not observed at the highest dose. With the application of LSW doses, there was a decrease in pH, ApH, PZSE, and an increase in CEC, PZC and ψo. Despite the increase in ψo, low clay dispersibility was observed. PHYSICAL OXISOL content (LSW Oxisols Oxisol s Cerrado 0, 0 (0 50 150 450 60 ha−1 ha1 ha 1 00.20 0020 0.20 20 0-0.2 replicates 30day day 30 mineralogical CDW, CDW , CDW) sodium SAR CEC V%, V V% V%) pH HO H O KCl ApH PZSE iµo EC analyses Ca K Mg Na dose ψo ( 5 15 45 6 ha− 00 00.2 002 020 0.2 2 0-0. 3 4 00. 02 0. 0-0 0-

ABSTRACT Proper waste management is a major worldwide concern; waste is disposed of directly into the environment, affecting water, soil and air quality. The development and production of green energy sources is strongly encouraged in modern society. The aim of this study, in accordance with Sustainable Development Goals (SDGs) 1, 2 and 7 of the 2030 Agenda of the UN, is to combine the correct disposal of animal waste with the generation of energy to mitigate the energy insecurity of families in an extremely vulnerable semi-arid region in the north-east of the country using biodigesters. To this end, a conceptual proposal was drawn up for a low-cost, easy-to-maintain and easy-to-use biodigester. A small-scale prototype was used to assess its operation by evaluating the main factors that affect biogas production (pH, temperature and the biomass properties: total solids, fixed solids, volatile solids, concentration of volatile fatty acids and C/N ratio). Evaluation of the test prototype gave satisfactory results that corroborate other studies and make it possible to propose an economically viable and efficient full-scale biodigester for biogas production. concern environment water quality society study SDGs (SDGs 1 203 UN semiarid semi arid northeast north east biodigesters end lowcost, lowcost low cost, cost low-cost easytomaintain easy maintain easytouse use smallscale small scale pH, pH (pH properties solids CN C N ratio. ratio . ratio) fullscale full 20

Even though ammonia is a natural component of aquatic environments, elevated concentrations indicate pollution and environmental degradation. Consequently, efficient analytical methods for monitoring ammonia levels are crucial for preserving water quality. Voltammetry offers a sustainable approach for NH3 quantification, combining good analytical performance with low sample and reagent consumption, minimizing waste generation. However, despite these advantages, the voltammetric determination of ammonia remains relatively unexplored. Therefore, this study investigated the electrochemical behavior of NH3 in alkaline solutions using a non-modified Pt electrode and evaluated the performance of differential pulse voltammetry (DPV) and square wave voltammetry (SWV) for NH3 determination. DPV provided superior performance, with limits of detection and quantification of 0.79 µmol L-1 (0.011 ppmN) and 2.6 µmol L-1 (0.036 ppmN), respectively, which comply with the maximum allowable ammonia concentration in natural waters according to Brazilian and European regulations. The voltammetric method successfully quantified ammonia in tap and river water samples, providing results concordant with the established Berthelot spectrophotometric method, at a 95% confidence level. Additionally, it is simple and fully accessible to non-electrochemist since no sophisticated procedures for electrode modification are needed. Finally, the high analytical performance of the proposed method makes it valuable for pollution monitoring in aquatic environments. environments degradation Consequently quality NH consumption generation However advantages unexplored Therefore nonmodified non modified (DPV SWV (SWV 079 0 79 0.7 L1 L 1 L- 0.011 0011 011 (0.01 ppmN 26 2 6 2. 0.036 0036 036 (0.03 ppmN, , respectively regulations samples 95 level Additionally nonelectrochemist electrochemist needed Finally 07 7 0. 0.01 001 01 (0.0 0.03 003 03 9 0.0 00 (0. (0 (

Seeking a viable alternative to fossil fuels as the primary energy source, bioethanol has emerged as a promising second-generation fuel derived from lignocellulosic biomass. With Brazil ranking pineapple as the third most produced fruit in temporary crops, this study aims to assess the impact of chemical pretreatment techniques, specifically organosolv and diluted acid, on the residual biomass of Pérola pineapple peel to enhance bioethanol production. Employing an experimental design that incorporates temperature, reaction time, and varying concentrations of organic solvent, the study examines their effects on the susceptibility of the substrate to saccharification for future bioethanol generation. Factors such as alphacellulose, hemicellulose, and lignin were evaluated in triplicate and subjected to statistical analysis using the Tukey test with a confidence level of 95%. Upon application of the pretreatment methods, it was observed that the organosolv solvent approach (utilizing water and ethanol) with sulfuric acid exhibited superior sugar conversion, yielding the highest concentration of xylose at 9.13 g L-1. Additionally, the pretreated biomass contained 1.38 g L 1 of cellobiose, 3.11 g L-1 of arabinose, and 3.76 g L-1 of glucose. This technique demonstrates promising potential for obtaining fermentable sugars crucial for bioethanol production. source secondgeneration second generation crops techniques production temperature time alphacellulose hemicellulose 95 95% methods utilizing ethanol conversion 913 9 13 9.1 L1. L1 1. Additionally 138 38 1.3 cellobiose 311 3 11 3.1 L- arabinose 376 76 3.7 glucose 91 9. 31 3. 37 7

Nanoparticles of TiO2 doped with low amount of Fe were synthesized from natural ilmenite obtained from alluvial gold mine wastes. The obtained TiO2 were characterized using X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FTIR), UV-Vis diffuse reflectance, thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), N2 adsorption-desorption isotherms, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The results confirm the formation of mesoporous TiO2 nanoparticles in anatase phase with 0.05 wt.% of iron possibly replacing some titanium places. All the characterizations were performed to the synthesized solid and the reference materials (TiO2 anatase and Degussa P25). The photocatalytic activity of both the synthesized solid and references were evaluated in the photo-oxidation of cyanide in aqueous medium under UV illumination. An experimental design type Box-Behnken was performed choosing three different parameters: the initial concentration of cyanide (50, 150 and 250 ppm) the catalyst load (0.1, 0.5 and 1.0 g L-1) and the oxygen source. The percentage of cyanide conversion was chosen as response in the design obtaining as optimal conditions [CN-]0 = 50 ppm, catalyst load = 0.6 g L-1 and air bubbling. Under these conditions it was reached 32, 32 and 89% of cyanide conversion for Fe-TiO2 synthesized, TiO2 anatase and Degussa P25, respectively. TiO wastes Xray X ray XRD, XRD , (XRD) XRF, XRF (XRF) Fouriertransform Fourier transform FTIR, FTIR (FTIR) UVVis Vis reflectance analysisdifferential analysis differential TGA/DSC, TGADSC TGA/DSC TGA DSC (TGA/DSC) N adsorptiondesorption adsorption desorption isotherms TEM (TEM XPS. XPS . (XPS) 005 0 05 0.0 wt wt. places (TiO P25. P25 P P25) photooxidation photo oxidation illumination BoxBehnken Box Behnken parameters 50, (50 15 25 ppm 0.1, 01 1 (0.1 5 0. 10 1. L1 L source CN0 CN [CN-] 06 6 L- bubbling 3 89 FeTiO2 FeTiO Fe-TiO respectively (XRD (XRF (FTIR (TGA/DSC (XPS 00 P2 (5 2 0.1 (0. [CN- 8 ( (0 [CN

ABSTRACT The aim of this study was to characterise the lignocellulosic fractions of pruning waste from tree species showing potential for furniture production in Acaraú, Ceará. The experiment was conducted in a completely randomised, split-plot design, with the plots corresponding to two water regimes (irrigated for one year and irrigated for three years) and the sub-plots to eight tree species, with three replications. The chemical attributes were determined after seven years. Except for the insoluble lignin content, there was a significant effect from the different species in terms of the chemical properties of the wood. The results for the lignocellulosic fractions show the possibility of developing technological ways of adding value to these waste products, especially considering their lignin content. The different species also showed potential for use in producing cellulose pulp, with the exception of Handroanthus impetiginosus due to its high ash content. The results of this study offer new perspectives for future research into the use of forestry waste. Acaraú Ceará randomised splitplot split plot design years subplots sub replications content wood products pulp

Abstract The aim of this study is to explore more sustainable approaches by replacing Portland cement (OPC) with recycled mixed powder (RMP) derived from construction and demolition waste (CDW), with a focus on reducing carbon emissions. The CDW was subjected to grinding and sieving until a fraction <0.15 mm was obtained. The particles were then thermally activated at 800°C in a muffle for 0.5, 1, 2, and 3 hours. The OPC replacement levels by RMP were defined based on the particle packing method, ranging from 0 to 65%. The study was carried out on pastes with a water/fines ratio ranging from 0.07 to 0.14 and superplasticizer admixture (SP), evaluating the compressive strength at 28, 63, and 91 days. The mechanical and environmental performance of Portland cement pastes composed with RMP showed compressive strength higher than the reference, reaching 37 MPa for a 45% replacement content at 28 days, reducing the CO2 emissions per m³ of paste by up to 53%. This study suggested that the treatment and packaging RMP particles may potentially increase the mechanical and environmental performance, making it an alternative to promote the circular economy and low-carbon cement. (OPC (RMP CDW, , (CDW) 015 15 <0.1 obtained 800C C 800 05 5 0.5 1 2 hours method 65 65% waterfines water fines 007 07 0.0 014 14 0.1 SP, SP (SP) 63 9 days reference 45 CO m 53 53% lowcarbon low (CDW 01 <0. 80 0. 6 00 (SP 4 <0 8 <

Resumo O objetivo deste estudo é explorar abordagens mais sustentáveis, substituindo o cimento Portland (OPC) por pó reciclado misto (RMP) derivado de resíduos de construção e demolição (RCD), focado na redução das emissões de carbono. O RCD foi submetido à moagem e peneiramento até a obtenção de uma fração < 0,15 mm. Em seguida, as partículas foram termicamente ativadas a 800°C em mufla por 0,5, 1, 2 e 3 horas. Os níveis de substituição de OPC por RMP foram definidos a partir do método de empacotamento de partículas, variando entre 0 e 65%. O estudo foi realizado em pastas com relação água/finos entre 0,07 e 0,14 e aditivo superplastificante (SP), com avaliação da resistência à compressão aos 28, 63 e 91 dias. Quanto ao desempenho mecânico e ambiental das pastas de cimento Portland compostas com RMP a resistência à compressão foi superior à referência, chegando a 37 MPa para um teor de substituição de 45% aos 28 dias, promovendo uma redução de 53% na emissão de CO 2 por m³ de pasta. O estudo indicou que tratar e empacotar as partículas de RMP aumenta o desempenho mecânico e ambiental, tornando-se alternativa para promover a economia circular e reduzir as emissões do cimento. sustentáveis (OPC (RMP RCD, , (RCD) carbono 015 15 0,1 mm seguida 800C C 800 05 5 0,5 1 horas 65 65% águafinos água finos 007 07 0,0 014 14 SP, SP (SP) 6 9 dias referência 45 53 m pasta tornandose tornando se (RCD 01 0, 80 00 (SP 4 8

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. disposal perspective preparation mortars bricks general produced demand metals hydration pretreatment pre however content hand limits Therefore

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. destinação perspectiva preparo utilizadas argamassas cerâmicos observados geral produzidos água misturas pesados cimento propuseram então prétratamento pré favorável porém satisfatório normativos Portanto ambiental

Abstract The use of supplementary cementitious materials to replace Portland clinker is one of the most effective strategies adopted by cement companies to reduce CO 2 emission on large-scale. However, due to the limited availability of traditional materials, alternative options are being investigated. The main objective of this research is to evaluate the characteristics and effect of different replacement levels of cement by dregs and grits on compressive strength. The wastes were ground and particles smaller than 75 µm were used. Chemical and physical were performed to characterize the dregs and grits. For both wastes, replacement levels of 0, 5, 10, 20 and 30% of cement mass were evaluated in the mortar production. The water-cement ratio and superplasticizer admixture content were kept constant. In fresh state, the consistency index and incorporated air content were obtained. Mortars made with dregs had higher strength compared to grits due to the higher combined water content. The results showed that it is possible to replace up to 36% of cement with dregs to obtain a strength of 25 MPa; and 15% for 40 MPa. largescale. largescale large scale. scale large-scale However investigated 7 used 0 5 10 30 production watercement constant state obtained 36 MPa 15 4 1 3

Resumo Ouso de adições minerais em substituição ao clínquer Portland é uma das medidas mitigadoras de emissão de CO2, mais promissoras em larga escala, adotadas pelas cimenteiras. Dada a limitação de disponibilidade de algumas, materiais alternativos vêm sendo investigados. A presente pesquisa teve como objetivo caracterizar e avaliar o efeito de diferentes teores de dregs e grits em substituição parcial ao cimento na resistência à compressão. Os resíduos foram submetidos à moagem, utilizando-se partículas inferiores a 75 µm. Foram realizados ensaios para caracterização química e física dos dregs e grits. Para ambos os resíduos, foram analisados os teores de 0, 5, 10, 20 e 30% em substituição à massa de cimento na produção de argamassas. A relação água/finos e o teor de aditivo superplastificante foram mantidos constantes. No estado fresco, foram avaliados o índice de consistência e o teor de ar incorporado. As argamassas com dregs proporcionaram maior resistência em relação às com grits devido ao maior teor de água combinada. Os resultados mostraram que é possível substituir até 36% do cimento por esse resíduo para obtenção de resistência à compressão de 25 MPa e 15% para 40 MPa. CO2 CO escala cimenteiras algumas investigados moagem utilizandose utilizando se 7 µm 0 5 10 2 30 águafinos finos constantes fresco incorporado combinada 36 15 4 1 3

Abstract The organic composition of 65 °% of urban solid waste of the Metropolitan District of Quito originates from food waste, which has negative environmental effects. The purpose of this study was to evaluate the factors related to food waste in homes in the capital and characterize urban solid waste management. The study is quantitative and exploratory. An association analysis was performed for the main categorical variables through calculation of statistical chi squared and an assessment of polychoric relation. A descriptive and multi-scale statistical analyses were performed for focus of the social metabolism to characterize waste management. A noteworthy element was the relation between expenses for purchase of food and non-alcoholic beverages in the last month-household income in the last month (p value < 5 %). Between 2012-2021, the most representative median for waste generation corresponded to the Eugenio Espejo administration, with 141470 t/ year, with a metabolic waste rate of 2.45E-05 (t/year). On the other hand, the Tumbaco administration obtained 30217 t/year and 1.22E-05 t/year, respectively.

Resumen La composición orgánica del 65 % de residuos sólidos urbanos del Distrito Metropolitano de Quito proviene de restos de alimentos, lo que provoca efectos medioambientales negativos. El propósito de esta investigación es evaluar los factores que inciden en el desperdicio de alimentos en los hogares capitalinos y caracterizar la gestión de sus residuos sólidos urbanos. La investigación es cuantitativa de tipo exploratoria. Se realizó un análisis de asociación entre las principales variables categóricas mediante el cálculo del estadístico chi-cuadrado y una evaluación de correlación policórica. Se aplicaron análisis estadístico descriptivo y multiescala del enfoque del metabolismo social para caracterizar la gestión de residuos. Destaca la relación entre el gasto en compra de alimentos y bebidas no alcohólicas en el último mes -ingreso del hogar en el último mes (p valor < 5 %). Entre 2012-2021, la mediana más representativa de generación de residuos corresponde a la administración Eugenio Espejo, con 141 470 t/año, y su tasa metabólica de residuos de 2,45E-05 t/año. En contraste, la administración Tumbaco obtuvo 30 217 t/año y 1,22E-05 t/año, respectivamente.

Resumo A composição orgânica do 65 °% dos resíduos sólidos urbanos do Distrito Metropolitano de Quito provém de restos de alimentos, o qual provoca efeitos negativos ao meio ambiente. O objetivo dessa investigação foi avaliar os fatores incidentes no desperdício de alimentos nos lares da capital e caracterizar a gestão dos resíduos sólidos urbanos. A pesquisa foi quantitativa e exploratória. Fez-se uma análise de associação das variáveis principais com o cálculo do chi-quadrado estatístico e uma avaliação da correlação policórica. Usaram-se análises estadísticos descritivos e multiescala do foco do metabolismo social para caracterizar a gestão dos resíduos. Destacou-se a relação do gasto para a compra de alimentos e bebidas não alcoólicas no último mês -rendas do lar no último mês (p valor < 5 %). Entre os anos 2012-2021, a mediana mais representativa de geração de resíduos foi da administração Eugenio Espejo, com 141 470 t/ano, e uma taxa metabólica de resíduos de 2,45E-05 t/ano. Em contraste, a administração Tumbaco teve 30 217 t/ano e 1,22E-05 t/ano, respetivamente.

Abstract Nowadays, organizations have the responsibility to commit themselves to actions that favor environmental conservation. The present study sought to explore an accompaniment for the management of the environmental component in the activities developed by an organization located in Armenia, Quindío-Colombia. Inter-institutional meetings were held in which a recognition, dialogue and workshop were conducted with the collaborators. A previously validated checklist was used. Subsequently, a descriptive analysis was made of the results obtained. It was found that 40 % of the components lacked actions for environmental conservation. Thus, the accompaniment showed that the collaborators committed themselves to use solid waste, save water and energy. The monitoring resulted in three strategic actions for the water, soil and energy components. The organization showed great interest in the process and an intersectoral link was established. The study proposes a baseline for the management of the environmental component of the study area; it resulted in an accompaniment and representative participation with significant progress towards the conservation of the environment within the organization.

Resumen Actualmente, las organizaciones se encargan de comprometerse con acciones que favorezcan la conservación del medioambiente. El presente estudio explora un acompañamiento para la gestión del componente ambiental en las actividades desarrolladas de una organización ubicada en Armenia, Quindío-Colombia. Se realizaron reuniones interinstitucionales en las que se realizó un reconocimiento, diálogo y taller con los colaboradores. Se utilizó una lista de verificación previamente validada. Posteriormente, se realizó un análisis descriptivo de los resultados obtenidos. Se encontró que el 40 % de los componentes carecen de acciones para la conservación del medioambiente. De tal manera, el acompañamiento arrojó que los colaboradores se comprometieron a aprovechar los residuos sólidos, ahorrar agua y energía. El acompañamiento derivó en tres acciones estratégicas para los componentes de agua, suelo y energía. La organización demostró un gran interés en el proceso y se logró establecer un vínculo intersectorial. El estudio plantea una línea base de gestión del componente ambiental del área de estudio; derivó en un acompañamiento y participación representativa con avances significativos hacia la conservación del medioambiente dentro de la organización.

Resumo Atualmente, as organizações têm a responsabilidade de se comprometerem com acções que favoreçam a conservação do ambiente. O presente estudo procurou explorar um acompanhamento para a gestão da componente ambiental nas actividades de uma organização situada em Armenia, Quindío-Colômbia. Foram realizadas reuniões interinstitucionais em que se procedeu a um reconhecimento, diálogo e workshop com os colaboradores. Foi utilizada uma lista de controlo previamente validada. Posteriormente, procedeu-se a uma análise descritiva dos resultados obtidos. Verificou-se que 40 % dos componentes careciam de acções para a conservação do ambiente. Desta forma, o acompanhamento mostrou que os colaboradores se comprometeram a utilizar os resíduos sólidos, a poupar água e energia. O acompanhamento resultou em três acções estratégicas para as componentes água, solo e energia. A organização mostrou grande interesse no processo e foi estabelecida uma ligação intersectorial. O estudo fornece uma base de referência para a gestão da componente ambiental da área de estudo; resultou num apoio e numa participação representativa com progressos significativos para a conservação do ambiente na organização.

Resumen:La demanda creciente del sector vivienda en la ciudad de Machala-Ecuador convirtió a las invasiones en el modelo común de crecimiento desorganizado de esta ciudad, donde utilizan el estero “El Macho” para la eliminación de desechos y aguas negras. Estudios preliminares respecto al contenido de metales pesados en este estero concluyen que las concentraciones de metales como el cadmio son superiores a los límites establecidos en la normativa del Texto Unificado de Legislación Secundaria del Ministerio del Ambiente. En la presente investigación se evaluó la remoción de cadmio de muestras de aguas del estero “El Macho” utilizando espuma de poliuretano activada con nanopartículas de plata como adsorbente. Para la recolección de los datos de adsorción se diseñó de un reactor tubular vertical, utilizando 1,560 g de adsorbente de poliuretano modificado con nanopartículas de plata, pH 8 y tamaño de la espuma de poliuretano de forma cubica de 0,5 cm de lado. Se cuantificó las concentraciones de cadmio mediante espectroscopia de absorción atómica, en muestras de aguas del Estero antes y después de su paso por el reactor. Se concluye que la espuma de poliuretano activada con nanopartículas de plata, como adsorbente, alcanzó un porcentaje de remoción de 48,75% y, por lo tanto, es efectivo para el tratamiento de aguas contaminadas con cadmio.

Abstract:The growing demand of the housing sector in the city of Machala-Ecuador turned invasions into the common model of disorganized growth of this city, where they use the “El Macho” estuary for the disposal of waste and sewage. Preliminary studies regarding the content of heavy metals in this estuary conclude that the concentrations of metals such as cadmium are higher than the limits established in the regulations of the Unified Text of Secondary Legislation of the Ministry of the Environment. In the present investigation, the removal of cadmium from water samples of the “El Macho” estuary was evaluated using polyurethane foam activated with silver nanoparticles as an adsorbent. To collect adsorption data, a vertical tubular reactor was designed, using 1,560 g of polyurethane adsorbent modified with silver nanoparticles, pH 8 and cubic-shaped polyurethane foam size of 0.5 cm of side. Cadmium concentrations were quantified by atomic absorption spectroscopy in samples of Estero water before and after passing through the reactor. It is concluded that the polyurethane foam activated with silver nanoparticles, as an adsorbent, reached a removal percentage of 48.75% and therefore, it is effective for the treatment of water contaminated with cadmium.

The water resources within the lower section of the Upper Vaal catchment, where the Vaal Barrage is situated, are highly utilised and developed, and water quality regulation has become a contested space between resource users and the regulators. The credibility and scientific defensibility of discharge standards in water-use licences (WULs), the relationship between upstream and downstream waste loads, the relationship between flows and water quality standards in WUL, and the water quality components of the resource quality objectives (RQOs) are being contested. This study explores the perceptions and motivations underlying these contestations as a contribution to scientific understanding of water quality management in a highly developed system. Perceived unrealistic RQOs, perceived lack of scientific credibility of the methods for deriving water quality standards in WUL, data inadequacy, as well as poor institutional capacity were identified as the top motivations for contesting applicable regulatory instruments in the catchment. Punitive measures, incentives, and education and awareness-raising were identified as key to accelerating compliance. Overall, this paper contributes to our general understanding of the intricacies of water quality management within a contested space. SIGNIFICANCE: Water quality management in South Africa is increasingly becoming a contested space, particularly in catchments that are highly developed and utilised. The findings in this study imply that (1) there is a need for a multi-pronged approach to increase water quality compliance, (2) there is a need for trust within the regulatory system to foster confidence among actors and stakeholders, and (3) transparent, open processes and scientifically credible and defensible methods, and data are needed for deriving standards in water-use licences (WULs).

Abstract: Environmental pollution from transportation has been a fundamental challenge for humanity throughout history, with conventional fuels contributing significantly to environmental degradation. This project seeks to suppress pollution and reduce noise generated by motorcycle taxis, whether for personal and/or private use. The main objective of the research work was to implement an electrolyzer in the combustion system of a motorcycle taxi to suppress environmental pollution and reduce noise. Methods included vehicle preparation, electrolyzer installation, battery adjustment, hydrogen generation, emissions measurement, safety, and data collection. As a result, the electrolyzer was implemented in the single-cylinder motorcycle taxi; The noise limit allowed at work in Peru is 85 dB, which is equivalent to 100 % noise at most; When using gasoline, a value of 76.4 dB was obtained, equivalent to 89.88 % noise, and when using hydrogen, a value of 71.7 dB was obtained, equivalent to 84.35 % noise, therefore, the total noise reduction was 4.70 dB (5.53 %) than established. The discussion highlighted that hydrogen is a clean fuel, with zero emissions and only emitting water vapor instead of polluting gases (5). The conclusion highlights the critical importance of the research, supported by the total reduction of 5.53 % of noise with this new technology and in turn external sources support that using hydrogen produced a smoother and quieter combustion; Regarding the useful life of the engine, due to the cleaner and more efficient combustion, the accumulation of waste was reduced, which benefits reducing the wear of internal components and the need for costly maintenance.

Resumen: La contaminación ambiental derivada del transporte ha sido un desafío fundamental para la humanidad a lo largo de la historia, con los combustibles convencionales contribuyendo significativamente a la degradación ambiental. Este proyecto busca suprimir la contaminación y reducir el ruido generada por mototaxis, ya sean de uso personal y/o privado. El trabajo de investigación tuvo como objetivo principal implementar un electrolizador en el sistema de combustión de un mototaxi para suprimir la contaminación ambiental y reducir el ruido. Los métodos incluyeron la preparación del vehículo, instalación del electrolizador, ajuste de la batería, generación de hidrógeno, medición de emisiones, seguridad y recolección de datos. Como resultado, se logró implementar el electrolizador en el mototaxi monocilíndrico; el límite de ruido permitido en el trabajo en el Perú es de 85 dB, que equivalen el 100 % de ruido como máximo; al utilizar gasolina se obtuvo un valor de 76.4 dB equivalentes a 89.88 % de ruido y al usar hidrógeno se obtuvo un valor de 71.7 dB siendo el 84.35 % de ruido, por lo tanto, la reducción total de ruido fue de 4.70 dB (5.53%) de lo establecido. La discusión destacó que el hidrógeno es un combustible limpio, con nulas emisiones y solo emitiendo vapor de agua en vez de gases contaminantes (5). La conclusión subraya la importancia crítica de la investigación, respaldada por la reducción total del 5.53 % de ruido con esta nueva tecnología y a su vez fuentes externas apoyan, que el utilizar hidrógeno produjo una combustión más suave y silenciosa. En cuanto a la vida útil del motor, la combustión más limpia y eficiente reduce la acumulación de residuos, lo que disminuye el desgaste de los componentes internos y la necesidad de mantenimientos costosos.

Globally, the demand for mineral products is ever increasing. Extraction of these mineral resources results in the continuous production of a huge volume of waste material, including tailing dumps. The mass of tailings usually exceeds the actual resource and often contains hazardous contaminants. This study investigated the effects of tailings disposal on soil, water, and air quality in the Nampundwe area. Water, soil, and dust samples were collected from different locations in the surrounding communities. The constituents analysed in the samples included copper, cobalt, iron, sulfate, and silica. According to the results obtained, some seepages occurred from the tailings impoundment to the shallow aquifer in the area. However, the general water quality meets the Zambia Environmental Management Agency (ZEMA) statutory limits. Recorded concentrations of sulfate (1500 mg/l), copper (1.5 mg/l), cobalt (1.0 mg/l), iron (2.0 mg/l), and silica were between 0.003 mg/l and 705 mg/l, which is far below ZEMA's statutory limit. Silica concentration was also evident in the air. The highest concentration recorded was 260 ppcc (particle per cubic centimeter) recorded in July 2019 from the northern direction of the tailings dam. The concentration was below the statutory limit of 350 ppcc. The topsoil from the northern part of the tailings recorded a silica dust concentration of 39.9 ppcc. Iron was evident in the underground soil with a concentration of 8.01 ppcc, cobalt 0.005 ppcc, copper 0.051 ppcc, while sulfate was recorded as 0.41 ppcc.