Resumo A crescente investigação da contaminação ambiental por cistos de Giardia spp. e seu impacto na saúde pública despertou o interesse em desenvolver métodos mais sensíveis para detectar esses protozoários, especialmente na água. No entanto, esses métodos ainda são complexos e dispendiosos. Este estudo teve como objetivo avaliar a eficiência de concentração e remoção de cistos de Giardia duodenalis usando um polímero floculante aniônico à base de acrilamida (AFP) em amostras de água de retrolavagem de filtro de uma estação de tratamento de água (ETA) localizada na cidade de Blumenau, sul do Brasil, e compará-lo com a técnica de floculação de carbonato de cálcio (CCF), rotineiramente usada em matrizes de água com alta turbidez. A taxa de recuperação média de cistos de G. duodenalis usando CCF e AFP foi de 33,33% e 43,33%, com uma redução média de turbidez de 98,39% e 98,78%, respectivamente. O uso de um polímero floculante aniônico provou ser uma alternativa eficiente para a concentração e remoção de cistos de protozoários em amostras de água com alta turbidez. É importante destacar que o desenvolvimento e a aplicação de novos estudos e estratégias que aumentem a eficiência da remoção desses organismos de matrizes ambientais complexas trariam benefícios tanto do ponto de vista da saúde pública quanto da perspectiva da saúde única. spp entanto dispendiosos (AFP ETA (ETA Blumenau Brasil comparálo compará lo CCF, , (CCF) G 3333 33 33,33 4333 43 43,33% 9839 98 39 98,39 9878 78 98,78% respectivamente única (CCF 333 3 33,3 433 4 43,33 983 9 98,3 987 7 98,78 33, 43,3 98, 98,7 43,

Abstract The increasing investigation into environmental contamination by Giardia spp. cysts and its impact on public health has spurred interest in developing more sensitive methods for detecting these protozoa, particularly in water. However, these methods remain complex and costly. This study evaluated the concentration and removal efficiency of Giardia duodenalis cysts using an acrylamide-based anionic flocculant polymer (AFP) in filter backwash water samples from a water treatment plant (WTP) located in Blumenau City, southern Brazil, and compared them with the calcium carbonate flocculation technique (CCF), which is routinely used for water matrices with high turbidity. The average recovery rates of G. duodenalis cysts using CCF and AFP were 33.33% and 43.33%, respectively, with an average turbidity reduction of 98.39% and 98.78%. The use of an anionic flocculant polymer proved to be an efficient alternative for the concentration and removal of protozoan cysts in water samples with high turbidity. It is important to highlight that the development and application of new studies and strategies aimed at increasing the efficiency of the removal of these organisms from complex environmental matrices would bring benefits to public health and promote a One Health perspective. spp protozoa However costly acrylamidebased acrylamide based (AFP WTP (WTP City Brazil CCF, , (CCF) G 3333 33 33.33 4333 43 43.33% respectively 9839 98 39 98.39 9878 78 98.78% perspective (CCF 333 3 33.3 433 4 43.33 983 9 98.3 987 7 98.78 33. 43.3 98. 98.7 43.

Resumen Los exopolisacáridos (EPS) pueden ser utilizados como agentes reductores confiriendo mejores propiedades físicas y químicas a las nanopartículas metálicas. Este estudio tuvo como objetivo sintetizar y evaluar las características fisicoquímicas, estructurales y funcionales de nanopartículas de ZnO producidas con EPS de Lactiplantibacillus fabifermentans BAL-27-ITTG. La caracterización estructural de los EPS exhibió una estructura de alto peso molecular compuesta principalmente de manosa y glucosa con enlaces α-1,4, α-1,3, α-1,6 de acuerdo con el espectro de RMN. El aumento de la concentración de EPS en la síntesis provoca el incremento en el tamaño de las partículas en escala micrométrica disminuyendo el índice de polidispersidad. La síntesis de las nanopartículas se confirmó mediante un barrido espectral UV-vis y el espectro FT-IR mostró picos de absorción a 600 cm-1 asociados al enlace Zn-O. Las nano (NP) y micropartículas (MP) sintetizadas mostraron actividades funcionales mejoradas respecto al EPS libre. Los valores máximos en actividad antioxidante (80.25 %), capacidad de retención de agua (3.06 g H2O/g muestra), actividad emulsionante (69.85 %) y actividad floculante (69.07 %) se obtuvieron con las MpZnO-EPS sintetizadas con 6 mg/mL del agente reductor. La actividad bacteriostática fue observada contra S. aureus y L. fabifermentans. La ausencia de hemólisis confirmó la biocompatbilidad de las partículas.

Abstract Exopolysaccharides (EPS) can be used as reducing agents and stabilizers, improving the physical and chemical properties of metallic nanoparticles. This study aimed to synthesize and evaluate the physicochemical, structural, and functional characteristics of ZnO particles obtained from EPS produced by Lactiplantibacillus fabifermentans BAL-27-ITTG. The structural characterization of the EPS exhibited a high molecular weight structure composed mainly of mannose and glucose, possibly linked by α-1-4, α-1-3, α-1-6 according to the RMN spectrum. The increase in EPS concentration during the synthesis leads to an increase of particle size at micrometric scale, decreasing the polydispersity index. The synthesis was confirmed with a UV-vis spectral scan, while the FT-IR spectrum showed absorption peaks at 600 cm-1 associated with the Zn-O bond. SSynthetized nano (NP) and microparticles (MP) showed improved functional characteristics comparing to free EPS. The highest values of antioxidant activity (80.25 %), water holding capacity (3.06 g H2O/g sample), emulsifying activity (69.85 %), and flocculant activity (69.07 %) were obtained from MpZnO-EPS synthetized with a concentration of 6 mg/mL of the reducing agent. Bacteriostatic activity was observed against S. aureus and L. fabifermentans. The absence of hemolysis confirms the biocompatibility of the particles.

Resumen El agua es un recurso cada vez más valioso porque su disponibilidad, principalmente, se limita a la precipitación y al almacenamiento de agua; por esa razón, el aumento de la densidad de población y el cambio climático pueden interferir con la accesibilidad al agua. Las actividades urbanas e industriales pueden producir aguas residuales y contaminar cuerpos de agua que podrían representar una fuente importante de agua; sin embargo, necesita ser tratado antes de su uso. La floculación es un importante método de eliminación de contaminantes para reducir una variedad de moléculas orgánicas e inorgánicas de las aguas residuales, utilizando las cargas intrínsecas del floculante para estabilizarlas/precipitarlas, por diferentes métodos, uno de ellos a través de un complejo polielectrolítico. La versatilidad de los floculantes depende de su capacidad para remover contaminantes y existen floculantes comerciales con eficiencias notables. Sin embargo, su toxicidad puede limitar su uso en cuerpos de agua o para uso humano anterior. Las investigaciones muestran que los polisacáridos son excelentes opciones como floculantes debido a su conformación de fácil carga y alto peso molecular para neutralizar contaminantes y precipitar flóculos, son biocompatibles, biodegradables y fáciles de modificar para modular la interacción floculante debido a la alta densidad del grupo funcional. Esta revisión explora las últimas investigaciones sobre la floculación de polielectrolitos de polisacáridos y sus derivados y su capacidad de remoción de contaminantes, los polisacáridos evaluados fueron los más investigados como quitosano, celulosa, quitina, alginato, gomas, dextrano, entre otros. Las tendencias de investigación recientes sobre la capacidad de floculación de estos polisacáridos mostraron resultados prometedores (hasta un 99% de eficiencia de remoción) con una amplia variedad de contaminantes, lo que los convierte en excelentes candidatos para su aplicación en la floculación verde.

Abstract Water is an increasingly valuable resource because its availability, primarily it is limited to precipitation and water storage; for that reason, increasing population density and climate change can interfere with water accessibility. Urban and industrial activities can produce wastewater and pollute waterbodies that could represent a significant water source; however, it needs to be treated prior to its use. Flocculation is an important pollutants removal method to reduce a variety of organic and inorganic molecules from wastewater, using the flocculant’s intrinsic charges to stabilize/precipitate them, by different methods, one of them being via polyelectrolyte complex. Flocculant versatility depends on its capacity to remove pollutants and there are commercial flocculants with remarkable efficiencies. However, their toxicity can limit their use in waterbodies or for former human use. Research shows that polysaccharides are great option as flocculants because of their easily charged conformation and high molecular weight to neutralize pollutants and precipitate flocs, they are biocompatible, biodegradable, and easy to modify to modulate the flocculant interaction due to the functional group’s high density. This review explores the latest research on polysaccharide polyelectrolyte flocculation and derivatives and their pollutant removal capacity, the polysaccharides evaluated were the most commonly researched such as chitosan, cellulose, chitin, alginate, gums, dextran, among others. Recent research tendencies on these polysaccharides flocculation capacity, showed promising results (up to 99% removal efficiencies) with a wide variety of contaminants, making them excellent candidates for their application in green flocculation.

ABSTRACT Due to a significant amount of nutrients in its composition, swine manure (SM) is commonly used to complement or replace commercial agricultural fertilizers. However, an improper application in crops could cause negative environmental impacts, especially due to the excessive supply of nutrients in its composition. This paper aimed to evaluate the removal of total Kjedahl nitrogen (TKN) and total phosphorus (TP) from SM biodigested by the coagulation/flocculation (CF) process with organic polymers. The SM samples were collected in two distinct seasonal periods (rainy and dry seasons), with CF tests in two stages. During the first stage, slow mixing times (SMTs) of 15, 20, and 25 min were tested, and in the second stage, the coagulant (0 – 1.75 g L-1) and flocculant dosage (0 – 0.0025 g L-1) effects were evaluated. The results show that the optimal SMT was 15 min in both the seasons. In the rainy season, the highest phosphorus and nitrogen removals were 80 and 27%, respectively, while in the dry season, the highest phosphorus and nitrogen removals were 70 and 25%, respectively. The finding shows that the use of flocculants did not improve the removal of TP and TKN when compared with the control conditions. It is concluded that the CF process can be used to remove TP and TKN from SM, with a possible concentration of them in the generated sludge. composition (SM fertilizers However impacts (TKN (TP coagulationflocculation coagulation flocculation (CF polymers seasons, seasons , seasons) stages stage SMTs (SMTs 20 2 tested 0 ( 175 1 75 1.7 L1 L L-1 00025 0025 0.002 evaluated season 8 27 27% respectively 7 25% conditions sludge 17 1. L- 0002 002 0.00 000 00 0.0 0.

RESUMO Por conter uma quantidade significativa de nutrientes em sua composição, a água residual de suinocultura (ARS) é comumente utilizada para complementar ou substituir fertilizantes agrícolas comerciais. No entanto, a aplicação inadequada nas culturas pode causar impactos ambientais negativos, especialmente devido ao aporte excessivo de nutrientes presentes em sua composição. Neste estudo, o objetivo foi avaliar a remoção de nitrogênio total Kjedahl (NTK) e fósforo total (FT) da ARS biodigerida pelo processo de coagulação/floculação com polímeros orgânicos. As amostras de ARS foram coletadas em dois períodos sazonais distintos (estações de chuva e seca), com testes de coagulação/floculação (CF) em duas etapas. Na primeira etapa, foram testados tempos de mistura lenta (TML) de 15, 20 e 25 minutos, e na segunda etapa, foram avaliados os efeitos da dosagem do coagulante (0 – 1,75 g L-1) e do floculante (0 – 0,0025 g L-1). Os resultados indicaram que o TML ótimo foi de 15 minutos em ambas as estações. Na estação chuvosa, as maiores remoções de fósforo e nitrogênio foram de 80 e 27%, respectivamente, enquanto que na estação seca, as maiores remoções de fósforo e nitrogênio foram de 70 e 25%, respectivamente. Verificou-se que a utilização do floculante não trouxe melhorias nas remoções de FT e NTK. Conclui-se que o processo de CF pode ser empregado na remoção de FT e NTK da ARS, com possível concentração desses no lodo gerado. composição (ARS comerciais entanto negativos estudo (NTK (FT coagulaçãofloculação coagulação floculação orgânicos estações seca , seca) (CF etapas etapa (TML 2 0 ( 175 1 75 1,7 L1 L L-1 00025 0025 0,002 L1. . chuvosa 8 27 27% respectivamente 7 25% Verificouse Verificou se Concluise Conclui gerado 17 1, L- 0002 002 0,00 000 00 0,0 0,

Abstract Context: Research has shown the efficiency of various treatments for sludge. However, new alternatives have been presented which merit an updated review. That is why this work aims to carry out said update with regard to conventional and new techniques to treat sludge. Method: The article is based on a review of documents in various databases, first grouping the conventional alternatives and later the new ones, both consisting of alternatives of sludge thickening, stabilization, and dewatering techniques, and analyzing them based on economic, technical, and environmental criteria. Results: This study found that direct osmosis is one of the most promising alternatives in sludge thickening, supercritical water oxidation, and pyrolysis in stabilization and vacuum filtration during the dehydration of said byproducts. Conclusions: This article allowed an updated review of conventional and new alternatives for sludge treatment, observing that, both in thickening and stabilization, the new alternatives are highly efficient, whereas vacuum filtration, a conventional alternative, improved its performance through the use of modified flocculants, standing out in the dehydration of sludge. This is why more research is required which improve the current challenges and yields and inquire into the release of pollutants into the environment when using biosolids.

Resumen Contexto: La investigación han demostrado la eficiencia de diversos tratamientos para lodos. Sin embargo, se han presentado nuevas alternativas que ameritan una revisión actualizada. Es por ello que este trabajo tiene como objetivo realizar dicha actualización con respecto a técnicas convencionales y nuevas para tratar los lodos. Método: Este artículo está basado en una revisión de documentos en diversas bases de datos, agrupando en primera instancia las alternativas convencionales y posteriormente las nuevas, constituidas ambas por alternativas de técnicas de espesamiento, estabilización y deshidratación de lodos, y analizándolas con base en criterios económicos, técnicos y ambientales. Resultados: En este estudio se encontró que la ósmosis directa es una de las alternativas más prometedoras en el espesamiento de lodos, la oxidación de agua supercrítica y la pirólisis en la estabilización y la filtración al vacío en la deshidratación de dichos subproductos. Conclusiones: Este artículo permitió la revisión actualizada de alternativas convencionales y nuevas para el tratamiento de lodos, observando que, tanto en el espesamiento como en la estabilización, las nuevas alternativas tienen eficiencias altas, mientras la filtración al vacío, una alternativa convencional, mejoró su rendimiento mediante el uso del floculante modificado, destacándose en la deshidratación de lodos. Es por ello que se requieren más investigaciones que mejoren los desafíos y rendimientos presentes e indaguen sobre la liberación al ambiente de contaminantes al utilizar los biosólidos.

ABSTRACT The objective of the article was to analyze the efficiency of cocoa (Theobroma cacao) shell flour in removing turbidity from domestic wastewater. The coagulant doses were 600, 800, and 1000 mg/L, with a fast speed of 180 RPM for one minute, a slow speed (40 and 60 RPM) for 15 minutes, and a settling time of 15 minutes. The volume of each jar was 1 L. A p-value of 0.001 was found for the slow speed factor; that is, there is a significant difference in turbidity for the two slow speed values. For the flocculant concentration factor, the p-value was 0.737; that is, there is no significant difference in turbidity for the four values of flocculant concentration. Likewise, the p-value for the (slow speed * concentration interaction) was 0.737; that is, it was not significant. It is concluded that the use of natural flocculants is a sustainable alternative for the removal of turbidity from domestic wastewater.

RESUMEN El objetivo del artículo fue analizar la eficiencia de la harina de cáscara de cacao (Theobroma cacao) en la remoción de turbidez de aguas residuales domésticas. Las dosis del coagulante fueron 600, 800 y 1000 mg/L, con velocidad rápida de 180 RPM por un minuto, velocidad lenta (40 y 60 RPM) por 15 minutos y tiempo de sedimentación de 15 minutos. El volumen de cada jarra fue de 1 L. Se encontró un p-valor de 0,001 para el factor velocidad lenta; es decir existe diferencia significativa de la turbidez para los dos valores de velocidad lenta. Para el factor concentración de floculante, el p-valor fue 0,737; es decir, no existe diferencia significativa de la turbidez para los cuatro valores de concentración de floculante. Asimismo, el p-valor para la interacción (velocidad lenta * concentración) fue 0,737; es decir no fue significativo. Se concluye que el uso de floculantes naturales es una alternativa sustentable para la remoción de turbidez del agua residual doméstica.

This study assessed the effects of volume concentration (0.3%, 0.6%, 1.2%, and 12% v/v) and type of polymer flocculant (acrylamide, chitosan, and purified and non-purified acrylamide grafted chitosan) on the flocculation mechanism of kaolinite-rich mining tailings samples. We measured the flocculated samples’ transmittance using UV-VIS spectrometry to check for particles in the supernatant medium in order to verify the flocculation efficiency. It was observed that flocculation directly depends on the pH of the medium, the isoelectric point of the kaolinite, and the polymer chains’ molecular mass. The concentration of H+ and OH- ions is responsible for producing charges of different electrical nature on the particles present in the suspension, thereby affecting the flocculation process. In the acrylamide samples, the aggregation of particles occurs by electrostatic interaction; and in the other samples by bridging, suggesting that the chains’ molecular mass interferes in the coagulation and flocculation mechanisms. Moreover, the results of absorbance measurements and flocs’ apparent density highlight that the grafting of acrylamide on the chitosan chain may improve the kaolin waste flocculation. For flocculant concentrations of up to 1.2% (v/v), the absorbances were mostly below 1.0, indicating removal of suspended materials.

RESUMO: O processo de colheita é um desafio atual para a produção comercial de microalgas porque a biomassa é diluída no meio de cultivo. Diversos métodos têm sido propostos para coletar células de microalgas, porém não existe um consenso sobre um método ótimo para tal aplicação. Neste estudo, métodos baseados em sedimentação, floculação e centrifugação foram avaliados na recuperação de Chlorella sorokiniana BR001 cultivada em um meio com baixo teor de nitrogênio. C. sorokiniana BR001 foi cultivada em um meio com baixo teor de nitrogênio para induzir ao acúmulo de lipídeos e carboidratos neutros. A biomassa de C. sorokiniana BR001 cultivada em um meio com baixo teor de nitrogênio apresentou um teor de lipídeos 1,9 vezes superior (23,8 ± 4,5%), quando comparada à biomassa produzida em um meio com alto teor de nitrogênio (12,3 ± 1,2%). Adicionalmente, a biomassa da linhagem BR001 cultivada em um meio com baixo teor de nitrogênio apresentou alto teor de carboidratos neutros (52,1 ± 1,5%). O processo baseado em sedimentação natural foi avaliado utilizando uma coluna de sedimentação e concluiu-se que C. sorokiniana BR001 é uma linhagem não floculante. Portanto, o efeito de diferentes concentrações de sulfato férrico (0,005 a 1 g L-1) ou sulfato de alumínio (0,025 a 0,83 g L-1) foram avaliados no processo de floculação de C. sorokiniana BR001, mas altas doses de floculantes foram necessárias para uma colheita de biomassa eficiente. Também foi avaliada a centrifugação em baixa velocidade (300 a 3.000 g), e foi possível concluir que este processo constituiu o mais adequado para a colheita da linhagem não floculante C. sorokiniana BR001.

ABSTRACT: The harvesting process is a current challenge for the commercial production of microalgae because the biomass is diluted in the culture medium. Several methods have been proposed to harvest microalgae cells, but there is not a consensus about the optimum method for such application. Herein, the methods based on sedimentation, flocculation, and centrifugation were evaluated on the recovery of Chlorella sorokiniana BR001 cultivated in a low-nitrogen medium. C. sorokiniana BR001 was cultivated using a low-nitrogen medium to trigger the accumulation of neutral lipids and neutral carbohydrates. The biomass of C. sorokiniana BR001 cultivated in a low-nitrogen medium showed a total lipid content of 1.9 times higher (23.8 ± 4.5%) when compared to the biomass produced in a high-nitrogen medium (12.3 ± 1.2%). In addition, the biomass of the BR001 strain cultivated in a low-nitrogen medium showed a high content of neutral carbohydrates (52.1 ± 1.5%). The natural sedimentation-based process was evaluated using a sedimentation column, and it was concluded that C. sorokiniana BR001 is a non-flocculent strain. Therefore, it was evaluated the effect of different concentrations of ferric sulfate (0.005 to 1 g L-1) or aluminum sulfate (0.025 to 0.83 g L-1) on the flocculation process of C. sorokiniana BR001, but high doses of flocculant agents were required for an efficient harvest of biomass. It was evaluated the centrifugation at low speed (300 to 3,000 g) as well, and it was possible to conclude that this process was the most adequate to harvest the non-flocculent strain C. sorokiniana BR001.

Resumo A preocupação com a exploração desenfreada dos recursos naturais tem aumentado nas últimas décadas, principalmente envolvendo a água e seu tratamento. Paradoxalmente, uma das fontes de poluição da água é justamente o seu tratamento, devido ao uso de floculantes químicos, que acabam gerando lodos que podem ser altamente agressivos ao meio ambiente. Uma das formas de resolver este problema é utilizar floculantes naturais para esta finalidade, uma vez que são biodegradáveis e não agridem a natureza. O objetivo deste trabalho foi avaliar a eficiência de um floculante natural produzido com taninos extraídos da casca do cajueiro (Anacardium occidentale) e compará-lo com dois coagulantes comerciais, Tanfloc® e cloreto de ferro. A água para tratamento foi coletada de um açude. A casca do cajueiro foi coletada, moída e submetida à extração em água quente para obtenção dos taninos, e o produto da extração foi cationizado. Os testes de floculação foram realizados utilizando-se o jar test com soluções nas concentrações de 33,3, 66,7 e 100 mg L-1. A turbidez e o pH foram analisados antes e após a floculação. Dentre os floculantes avaliados, os taninos cationizados produziram as melhores respostas tanto para remoção de turbidez quanto para pH final da água tratada. O Tanfloc® também apresentou resultados satisfatórios quanto à remoção de turbidez. O cloreto de ferro, além de não clarificar adequadamente a água, a deixou muito ácida. Como os taninos cationizados praticamente não alteraram o pH e foram eficazes na remoção da turbidez, consistem em um produto interessante para o tratamento da água.

Abstract Concern about the overexploitation of natural resources has increased in recent decades, especially involving water and its treatment. Paradoxically, one of the sources of water pollution is the treatment itself, due to the use of chemical flocculants, which end up generating sludge that may be highly aggressive to the environment. One of the ways to solve this problem is to use natural flocculants for this purpose, since they are biodegradable and do not harm nature. This study evaluated the efficiency of a natural flocculant produced from tannins extracted from the bark of the cashew tree (Anacardium occidentale) and compared it with two commercial coagulants, Tanfloc® and iron chloride. The water for treatment was collected from a weir. The cashew trees’ bark was collected, ground, and submitted to hot-water extraction to yield the tannins, and the extraction product was cationized. The flocculation tests were carried out using the jar test with solutions having concentrations of 33.3, 66.7, and 100 mg L-1. Turbidity and pH were analyzed before and after flocculation. Among the assessed flocculants, the cationized tannins produced the best responses both for removal of turbidity and final pH of the treated water. Tanfloc® also produced satisfactory results regarding turbidity removal. The iron chloride, besides not properly clarifying the water, left it very acidic. Since the cationized tannins practically did not change the pH and were effective in the removal of turbidity, they represent an interesting, sustainable alternative product to treat the water.

RESUMEN La eliminación de iones sulfatos desde aguas naturales, así como de efluentes industriales de diferentes orígenes, es un problema, considerando que la mayoría de los procesos propuestos son ineficientes y de alto costo, principalmente cuando se requiere reducir la concentración de iones sulfato a valores inferiores a 500 mg.L-1. La técnica de flotación combinada con precipitación ha demostrado ser eficiente para la eliminación de iones d metales pesados. Sin embargo, no hay suficientes investigaciones que confirmen su eficiencia para la eliminación de iones sulfato. Este artículo presenta los resultados de la remoción de iones sulfato desde soluciones sintéticas preparadas en un medio ácido, aplicando las técnicas de co-precipitación con policloruro de aluminio (PAC) y separación sólido/líquido mediante flotación por aire disuelto (FAD). Se estudiaron el efecto del pH, la razón [PAC: iones sulfato], el efecto del flujo de agua saturada con aire y las dosis de floculante y colector. Los resultados alcanzados confirman que es posible reducir la concentración de iones sulfato de 1 800 a 350 mg.L-1 (80% de remoción) desde soluciones sintéticas aplicando la técnica de flotación combinada con precipitación.

ABSTRACT The removal of sulfate ions from natural waters, as well as from industrial effluents of different origins, is a problem, considering that most of the proposed processes are inefficient and have a high cost, mainly when reducing the sulfate ion concentration to values below 500 mg.L-1 is required. The flotation technique, combined with precipitation, has proven to be efficient for the removal of heavy metal ions. However, there is not enough research to confirm its efficiency for the removal of sulfate ions. This article presents the results of sulfate ion removal from synthetic solutions prepared in an acidic medium, applying the co-precipitation techniques with polyaluminum chloride (PAC) and solid/liquid separation by dissolved air flotation (DAF). The effect of the pH, the [PAC: sulfate ions] ratio, the effect of saturated water flow with air, and the flocculant and collector doses were studied. The achieved results confirm that it is possible to reduce the concentration of sulfate ions from 1 800 to 350 mg.L-1 (80% removal) from synthetic solutions by applying the flotation technique combined with precipitation.

RESUMEN Se determinaron las condiciones óptimas para maximizar el porcentaje de remoción de los metales pesados como iones Pb 2+ y Zn 2+ de soluciones binarias acuosas mediante el uso de una zeolita químicamente modificada llamado NeoniteMR. De la caracterización por DRX, FRX, FTIR y adsorción-desorción de N , se establece que el NeoniteMR está compuesto principalmente por la zeolita natural clinoptilolita, teniendo SiO2, Na2O, SO3 y Al2O3 como los componentes principales; la relación Si/Al fue de 3,8 y los principales cationes intercambiables son Na+, Ca2+ y K+, el área de superficie BET fue de 24,31 m2/g. El diseño Box Behnken para cuatro factores, [Pb2+], [Zn2+], dosis de Neonite y pH a tres niveles, fue usado para construir modelos cuadráticos de segundo orden, los que presentaron un coeficiente de determinación R2 ajustado de 0.8680 y 0.9614 para el porcentaje remoción de Pb 2+ y Zn 2+ respectivamente; finalmente estos modelos fueron validados mediante los análisis de residuales, distancia de Cook y el valor de apalancamiento. En base a los modelos, no hay una clara influencia de los factores en la remoción del Pb 2+ , mientras que el pH es muy influyente en la remoción del Zn 2+ . Usando la función de deseabilidad global se determinó que la máxima remoción de los iones plomo y zinc fue 98,80% y 93,48% respectivamente, a las condiciones óptimas de concentración de Pb 2+ y Zn 2+ de 20 ppm, dosis del Neonite de 442,42 mg/L y pH igual a 8.

ABSTRACT Optimal conditions were determined to maximize the removal percentage of heavy metals such as Pb2+ and Zn2+ ions from transparent binary solutions by using a zeolite chemically called Neonite™. From the characterization by XRD, XRF, FTIR and adsorption-desorption of N2, it is established that Neonite™ is mainly composed of the natural zeolite clinoptilolite, having SiO2, Na2O, SO3 and Al2O3 as the main components; the Si/Al ratio was 3,8 and the main exchangeable cations are Na+, Ca2+ and K+, the BET surface area was 24,31 m2/g. The Box Behnken design for four factors, [Pb 2+ ], [Zn 2+ ], Neonite dose and pH at three levels, was used to build second order quadratic models, which presented an adjusted coefficient of determination R2 of 0,8680 and 0,9614 for the removal percentage of Pb2+ and Zn2+ respectively; finally, these models were validated through residual analysis, Cook's distance and leverage value. Based on the models, there is no clear influence of the factors on the removal of Pb2+, while the pH is very influential on the removal of Zn2+. Using the global desirability function, it will be shown that the maximum removal of lead and zinc ions was 98,80% and 93,48%, respectively, at the optimal conditions of concentration of Pb 2+ and Zn 2+ of 20 ppm, dose of Neonite of 442,42 mg/L and pH 8.

Abstract The present study shows the strategies used to improve the treatment of clarification of demineralized water in GENSA S. A. E. S. P., Planta Termopaipa, located in Boyacá, Colombia. Experimental data obtained from jar tests were used to build a model based on neuronal nets. The independent variables were pH, turbidity, electrical conductivity, and color of the raw water along with flocculent dosage. The output variable was the Aluminum Sulfate dosage. A three-layer neural network was chosen as a prediction approach. The model was validated to find ten neurons in the hidden layer. Nonlinear optimization was the tool used to train the neural network. The chi- square value was used to test the model and showed that the model is efficient at 90% confidence level.

Resumen El presente estudio muestra las estrategias usadas para mejorar el proceso de clarificación en la planta de agua desmineralizada en la planta GENSA S. A. E. S. P., de Termopaipa, localizada en Boyacá, Colombia. Se emplearon datos experimentales obtenidos a partir de la prueba de jarras para construir un modelo basado en redes neuronales. Las variables independientes fueron pH, turbiedad, conductividad eléctrica y color del agua cruda, junto con la dosis de polímero floculante. La variable de salida del modelo fue la dosis del coagulante. Se escogió el modelo de una red neuronal de tres capas, el cual fue validado para encontrar 10 neuronas en la capa oculta. La herramienta para entrenar la red neuronal fue optimización no lineal. El cálculo de chi cuadrada utilizado para la evaluación del modelo demostró ser eficiente en un 90% de nivel de confianza.

ABSTRACT The objective of this study was to evaluate the physicochemical treatment of wool washing effluents from a textile industry in the city of Arequipa in order to comply with the Maximum Admissible Values (VMA), using 40% ferric trichloride as coagulant and 0,1% MT-FLOC 4299 polymer flocculant. The effluent was physically and chemically characterized at the beginning and at the end of the treatment, measuring pH, temperature, Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), total suspended solids (TSS), oils and fats, sulfates, ilosulphides, ammoniacal nitrogen, total cyanide, hexavalent chromium and turbidity. To determine the optimal doses of coagulant and flocculent, three treatments were done using a jug set at 50, 200 and 40 rpm. The sedimentation time of the floc was 10 minutes. The initial turbidity ranges oscillated between 200 and 800 NTU, obtaining a removal of 89 % in relation to the average turbidity of 526.96 NTU. The best dose applied to the effluent was 200 mg/L of ferric trichloride and 0,8 mg/L of the cationic polymer flocculent MT- FLOC 4299. The contaminant removal parameters were: 84,97 % oils and fats; 82,55 % Biochemical Oxygen Demand; 79,36 % Chemical Oxygen Demand; 99,60 % suspended total solids; 96,67 % settleable solids and 75,65% total cyanide, thus complying with the Peruvian Regulations, so it is feasible to apply the treatment on a larger scale.

RESUMEN El objetivo del presente estudio fue evaluar el tratamiento fisicoquímico de los efluentes de lavado de lana provenientes de una industria textil de la ciudad de Arequipa con la finalidad de cumplir con los Valores Máximos Admisibles (VMA), utilizando como coagulante tricloruro férrico al 40 % y floculante polímero MT-FLOC 4299 al 0,1 %. Se caracterizó física y químicamente el efluente al inicio y al final del tratamiento, midiendo pH, temperatura, demanda bioquímica de oxígeno (DBO5), demanda química de oxígeno (DQO), sólidos totales suspendidos (TSS), aceites y grasas, sulfatos, sulfuros, nitrógeno amoniacal, cianuro total, cromo hexavalente y turbidez. Para determinar las dosis óptimas de coagulante y floculante se realizaron tres tratamientos utilizando un equipo de jarras (Jar-test) a 50, 200 y 40 rpm. El tiempo de sedimentación fue de 10 minutos. Los rangos de turbidez inicial oscilaron entre 200 y 800 NTU obteniéndose una remoción del 89 % en relación a la turbidez promedio de 526,96 NTU. La mejor dosis aplicada al efluente fue 200 mg/L de tricloruro férrico y 0,8 mg/L del floculante polímero catiónico MT-FLOC 4299. Los parámetros de remoción de contaminantes fueron: 84,97 % aceites y grasas; 82,55 % demanda bioquímica de oxígeno; 79,36 % demanda química de oxígeno; 99,60 % sólidos totales suspendidos; 96,67 % sólidos sedimentables y 75,65 % cianuro total, cumpliendo así con la Normativa Peruana, por lo que es factible aplicar el tratamiento a mayor escala.

ABSTRACT The most used method for the disposal of phosphates tailings is through of tailing dams conventional. The tailing disposal in the form of mineral paste has advantages compared with the disposal conventional. The objective of this work is the production and characterization of mineral pastes from phosphates sludges using a thickener in laboratory scale. The main results were: a) the specific gravity of solid material: 2.61 g/cm3; b) sludge 100% < 30 μm; c) the chemical analysis indicated the principals presence of magnesium, calcium, phosphorus and oxygen; d) the mineralogy detected the presence calcite and dolomite as main phases; e) sample showed high value of the superficial specific area through Blaine method was 0.976 m2/g; f) the thickening tests time required for maximum compression point of phosphate mud without the use of flocculant was 7,200 s; g) the tests continuous sedimentation using recirculation and the use of flocculant selected increased by approximately 6% solids in the underflow; h) a transition stage of high slurry density to mineral paste in the range between 55% and 58% solids was observed; i) concerning to generations of flocs, the FGR system presented a discharge more dense of solids concentration in all operational range; j) an increase of around 7% solids in the underflow was noted using rake system; k) with the best operational conditions in the equipment were obtained paste minerals of 70% solids; l) the yield stress of phosphate sludge showed values greater than 80 Pa from 65% solids characteristic of mineral paste.

RESUMEN El método más utilizado para la disposición de los relaves fosfáticos es vía tranque convencional de relaves. La disposición de relaves en forma de pasta mineral presenta ventajas sobre la disposición convencional. El objetivo de este trabajo fue la producción y caracterización de pastas minerales desde lamas fosfáticas utilizando un espesador en escala de laboratorio. Los principales resultados fueron: a) peso específico del material sólido: 2,61 g/cm3; b) lama 100% < 30 μm; c) el análisis químico reveló presencia principal de magnesio, calcio, fósforo y oxígeno; d) el análisis mineralógico indicó predominancia de calcita y dolomita; e) la muestra presentó elevado valor de área superficial específica de 0,976 m2/g; f) en los ensayos de espesamiento el tiempo requerido para el punto máximo de compresión sin floculante fue 7.200 s; g) los ensayos de sedimentación continua con recirculación y floculante aumentaron alrededor de 6% sólidos en la descarga; h) el perfil de concentración del sedimento exhibe una transición de pulpa de alta densidad a pasta mineral entre 55% y 58% sólidos; i) respecto a la generación de flóculos el sistema RGF presentó una descarga más densa de concentración de sólidos en todo el rango operacional; j) el sistema de rastras presentó un aumento alrededor de 7% sólidos en la descarga; k) con las mejores condiciones operacionales fueron obtenidas pastas minerales de 70% sólidos; l) el esfuerzo de cedencia tuvo valores superiores a 80 Pa desde 65% de sólidos característica de una pasta mineral.

Resumen Contexto: Las saponinas corresponden a un grupo de moléculas con aplicabilidad industrial, especialmente para el sector alimenticio como estabilizante de espuma en bebidas gaseosas. En el período comprendido entre el 2013 y 2017, su mercado incrementó aproximadamente un 50%, convirtiéndose en un sector económico importante que ha promovido un marcado interés en la optimización de diversos procesos de extracción desde diferentes fuentes naturales. Método: Se realizó una revisión bibliográfica evaluando aplicabilidad, extracción y aspectos económicos de las saponinas a nivel mundial. Se realizó el diseño conceptual de una planta piloto para la extracción de saponinas de jugo de fique con base en los resultados obtenidos del análisis de una matriz de decisión. Resultados: Una alternativa viable para extraer saponinas de jugo de fique es la floculación, cuyas ventajas radican en sus implicidad tecnológica, bajo consumo energético, aplicabilidad directa a la matriz de interés y uso de solventes como agua y etanol. Conclusiones: Al utilizar como floculante el policloruro de aluminio (PAC), debido a su capacidad de remover materia orgánica y a su selectividad, se favorece la recuperación de las saponinas en el clarificado. En el diseño conceptual, se presenta una planta piloto con una capacidad de 67.462 L/h y una eficiencia de 87,45%.

Abstract Context: Saponins belong to a group of molecules with industrial applications, particularly in the food industry as a foam stabilizer in soft drinks. During 2013 to 2017, its market increased about 50%, becoming an important economic sector that has promoted a strong interest in the optimization of different extraction processes from different natural sources. Method: A technological surveillance report wasma de evaluating the applicability, extraction and economic aspects of saponins worldwide. The conceptual design of a pilot plant for the extraction of saponins from fique’s juice was carried out based on the results obtained from the analysis of a decision matrix. Results: A viable alternative for the extraction of saponins from fique’s juice is flocculation, which advantages lie on its technological simplicity, low energy consumption, direct applicability to the matrix of interest and use of solvents such as water and ethanol. Conclusions: Using Aluminum Polychloride (PAC) as a flocculant, due to its ability to remove organic matter and its selectivity, saponins are recovered in the clarification. The conceptual design presents a pilot plant with a capacity of 67.462 L/h and an efficiency of 87,45%.