Employment of chitosan in the removal of pollutants in fish processing effluents / [Emprego de quitosana na remoção de poluentes em efluentes de processamento de pescado]

The significant growth of the industrial sector in recent decades has led to an increase in the volume of waste, which if not properly destined, could cause serious environmental problems. In the context of aquaculture, liquid effluents with a high organic content are generated in large quantities in the fish processing industries, and if their disposal is carried out improperly, serious damage to the environment is caused. The general objective of this study is to evaluate: the efficiency of removal of COD and BOD, in addition to the influence on pH; alkalinity; chlorides; ammonia; nitrite; nitrate; phosphate; turbidity; total, fixed and volatile solids, from the effluent of fish processing treated by coagulation and sedimentation using the natural chitosan coagulant. pH 5.5 followed by pH 6 showed better results for the use of chitosan coagulant in the process of treatment by effluent coagulation of fish processing industry. Chitosan does not act on the parameters TVS, alkalinity, chlorides, ammonia, nitrite, nitrate, and phosphate, regardless of the dosage used. However, it acts on BOD, COD, TS, TFS and turbidity. Thus, the best dosage of chitosan is 0.25 g L-1 in optimized activity at pH of 5.5.

O crescimento expressivo do setor industrial nas últimas décadas acarretou o aumento do volume de resíduos, que, se não forem destinados adequadamente, poderão causar sérios problemas ambientais. No contexto da aquacultura, efluentes líquidos com um alto teor orgânico são gerados em grandes quantidades nas indústrias de processamento de pescado, e, se seu descarte for realizado de maneira inadequada, há sérios prejuízos ao ambiente. O objetivo geral deste estudo foi avaliar: a eficiência de remoção de DQO e DBO, além da influência sobre o pH, a alcalinidade, os cloretos, a amônia, o nitrito, o nitrato, o fosfato, a turbidez, os sólidos totais, fixos e voláteis, bem como do efluente do processamento de pescado tratado por coagulação e da sedimentação, utilizando-se o coagulante natural quitosana. O pH 5,5, seguido pelo pH 6, apresentou melhores resultados para uso do coagulante quitosana no processo de tratamento por coagulação de efluente de indústria de processamento de pescado. A quitosana não atua sobre os parâmetros STV, alcalinidade, cloretos, amônia, nitrito, nitrato e fosfato, independentemente da dosagem utilizada. Mas atua sobre DBO, DQO, ST, STF e turbidez. Assim, a melhor dosagem de quitosana é 0,25 g L-1 em atividade otimizada no pH de 5,5.

The bell jar / La campana de cristal

Review of the book: The bell jar, of Sylvia Plath. Random House, 2020.

Reseña del libro: La campana de cristal, de Sylvia Plath. Literatura Random House, 2020.

Production and physicochemical characterization of chitosan for the harvesting of wild microalgae consortia.

The use of chitosan to harvest microalgae is a strategic step that seeks to reach an economically competitive price to recover lipids, proteins, and pigments. The aim of the present work was to design low-molecular-weight chitosan from shrimp shells and its physicochemical characterization, to be used for the harvesting of wild microalgae consortia. The chitosan was obtained by chemical deacetylation of shrimp shells, and physicochemical characterization was made using the instrumental methods DSC, TGA, X-ray, FTIR, and SEM. The harvesting of wild microalgae consortia was performed by the jar test method. The obtained chitosan had a low molecular weight (169 KDa), a deacetylation degree of 83 %, a decomposition temperature (TD) of 280 °C, and a crystallinity of 38.2 %. The microalgae genera found in the consortium were Scenedesmus sp., Chlorella sp., Schroderia sp., and Chlamydomonas sp. The microalgae removal efficiency of the chitosan was 99.2 % with 20 mg L-1.

Life cycle inventory data for banana-fiber-based biocomposite lids.

This data article is related to the research article "Comparative life cycle assessment of coffee jar lids made from biocomposites containing poly (lactic acid) and banana fiber". The article reports the model parameters used to construct each stage and unit process inventory of the life cycle of coffee jar lids, and the subsequent inventories of the investigated system. It also contains details of calculations and descriptions of inventory uncertainties. Primary data were obtained from lab-scale and pilot-scale tests during product preparation. Secondary data collection was based on detailed review of related international and regional literature, databases and recognized web sites. The data presented here can be used by future life cycle assessment studies on natural fiber composites in packaging applications.

Comparative life cycle assessment of coffee jar lids made from biocomposites containing poly(lactic acid) and banana fiber.

Composites containing bio-based materials, like banana fiber and poly(lactic acid) (PLA), are potential food-packaging materials. We carried out an environmental life cycle assessment (LCA) of coffee jar lids made from high density polyethylene (HDPE), PLA, and banana fiber to assess their environmental performance. We considered differences in the type of blend (content of PLA and banana fiber in the composite), origin of the banana fiber feedstock (considered as either biowaste or as a co-product from banana production) and banana fiber pretreatment conditions (either no pretreatment or pretreatment using chemicals). Irrespective of the scenario, a lid made from 40% banana fiber and equal amounts of HDPE and PLA performed significantly better in all 18 impact categories when compared to a lid made from 100% PLA. By contrast, the same lid performed significantly better in 3 impact categories only (climate change, photochemical oxidant formation and fossil depletion) when compared to a lid made from 100% HDPE. Thus, environmental performance of the biocomposite strongly depends on which polymer base is replaced by the banana fiber in the composite. Replacing PLA with banana fiber is generally expected to bring environmental benefits.

Response surface methodology applied to tropical freshwater treatment.

This paper presents the profits and disadvantages of the chemometrics approach instead of the one-factor-at-a-time (OFAT) coagulation diagram approach for tropical water physicochemical treatment. Central composite design associate to response surface methodology (CCD-RSM) is used to find the real best conditions for coagulant dosage and pH aiming at high-turbidity removal. The number of experiments needed to chemometrics model construction (12) is comparatively smaller than that used in the coagulation diagram (84), saving financial and environmental resources. Arguments for Water Treatment Plants (WTP) considering the replacement of coagulation diagram approach by the CCD-RSM approach in drinking water treatment are presented. Chemometrics models are all constructed on a free software platform, providing the best pH within the range 7.7-8.1, and the best coagulant dosage (polyaluminium chloride, PAC) between 2.0 and 3.1 mg Al2O3 L-1 (equivalent in mass). CCD-RSM provides a faster, lower-cost and more reliable alternative tool for WTP decision-making instead of the OFAT model, mainly for waters more affected by seasonal effects as can be seen in tropical and subtropical countries.

Consumers' Sensory Perception of Food Attributes: Identifying the Ideal Formulation of Gluten- and Lactose-Free Brownie Using Sensory Methodologies.

Products for consumers with special needs (celiac) and those who prefer a differentiated diet are necessary due to growing demand and a niche market to be exploited. The incorporation of other substances in the formulation of cakes requires a detailed analysis of their characteristics and sensorial attributes. However, the use of these flours may change the sensory characteristics of a product that is normally made from wheat flour. This study aimed to identify the ideal formulation of gluten- and lactose-free brownies made with rice flour and beans/lentils in consumer perception, through the combination of sensory tests. Using these data, the aim was to define recommendations for the reformulation of a product of high consumer acceptance, using easily accessible ingredients. The sensory methods used were descriptive analysis with a group of 20 trained evaluators and a group of 100 consumers evaluated through the check-all-that-apply and just-about-right questionnaire; all groups performed the acceptance test by hedonic scale. Data were analyzed using multivariate techniques and correlation matrices. The results showed that the attributes selected by the trained evaluators and consumers were sufficient to indicate that color and texture were the most striking characteristics that should be improved in brownie formulations without gluten and lactose. PRACTICAL APPLICATION: The study assumes that from the combination of sensory methods it is possible to verify the attributes that are most attractive to consumers in gluten-free and lactose-free cake formulations, using easily accessible ingredients that have technological, nutritional, and sensory quality, such as those formulated with wheat.

Evaluación del quitosano como coagulante para el tratamiento de efluentes piscícolas / Evaluation of chitosan as a natural coagulant for fish effluents treatment

RESUMEN El uso de polímeros orgánicos para el tratamiento de aguas residuales a través de procesos de coagulación/floculación presenta ventajas sobre el uso de coagulantes inorgánicos, debido a la biodegradabilidad y la baja toxicidad en el agua de estos. El quitosano es un biopolímero que se ha utilizado como coagulante en el tratamiento de aguas residuales. En este estudio, se evaluó el quitosano como coagulante natural utilizado en la clarificación de efluentes piscícolas en tecnología biofloc (BFT) y en sistema de recirculación acuícola (RAS). Se implementó un diseño experimental completamente aleatorizado, de una vía, con efectos fijos. Los ensayos del agua se llevaron a cabo por el método de jar-test, donde se aplicaron dosis de quitosano de 3, 6, 9, 12 y 15 mg/L. Se analizó el efecto estadístico de la dosis de quitosano en la eliminación de la turbidez, sólidos suspendidos totales (SST) y sólidos suspendidos volátiles (SSV) del agua. Se encontró efecto del quitosano sobre la turbidez, dosis de 9 mg/L logró remociones del 88% y valores de 3.9 NTU (con error < 0.05). Sin aplicar quitosano al efluente, se lograron remociones de 78.2 y 76.7% para SST, SSV respectivamente. El quitosano permitió eliminar turbidez del efluente (BFT).

ABSTRACT Using organic polymers for wastewater treatment through coagulation/flocculation processes is more advantageous than current approach based on inorganic coagulants, due to the former's biodegradability and low toxicity in the water. Chitosan is a biopolymer that has been used as coagulant in wastewater treatment. In this study, chitosan was evaluated as a natural coagulant used in the clarification of fish effluents in biofloc technology (BFT) and aquaculture recirculation system (RAS). A one-way completely randomized experimental design with fixed effects was implemented. The water clarification tests were conducted using the jar test method with chitosan doses of 3, 6, 9, 12 and 15 mg/L. The chitosan dose effect was analyzed as natural coagulant on the removal of the water's turbidity, total suspended solids (SST) and volatile suspended solids (SSV). The effect of the chitosan load on the turbidity removal was found, as optimal dose of 9 mg/L for 88% with final turbidity value of 3.9 NTU (with significance < 0.05). In absence of chitosan, only values of 78.2 and 76.7% for SST and SSV were reached, respectively. Chitosan allowed the removal of turbidity from the water (BFT).

Performance comparison of three methods for detection of Giardia spp. cysts and Cryptosporidium spp. oocysts in drinking-water treatment sludge.

Detecting pathogenic protozoa in drinking-water treatment sludge is a challenge as existing methods are complex, and unfortunately, there are no specific technical standards to follow. Selecting an efficient analytical method is imperative in developing countries, such as Brazil, in order to evaluate the risk of parasite infection. In this context, three methods to detect Giardia spp. cysts and Cryptosporidium spp. oocysts were tested in sludge generated when water with protozoa and high turbidity was treated. Jar testing was carried out using polyaluminium chloride as a coagulant to generate the residue to be analyzed. The results showed that calcium carbonate flocculation with reduced centrifugation and immunomagnetic separation obtained the highest recoveries in the tested matrix showing 60.2% ± 26.2 for oocysts and 46.1% ± 5 for cysts. The other two methods, the first using the ICN 7× cleaning solution and the second considering the acidification of the sample, both followed by the immunomagnetic separation step, also presented high recoveries showing 41.2% ± 43.3 and 37.9% ± 52.9 for oocysts and 11.5% ± 85.5 and 26% ± 16.3 for cysts, respectively. Evidently, these methods and others should be studied in order to make it possible to detect protozoa in settled residue.

Re-examining the early history of the Leiden jar: Stabilization and variation in transforming a phenomenon into a fact.

In this paper, we examine the period that immediately followed the invention of the Leiden jar. Historians of science have developed narrations that emphasize the role of grounding during the process of charging the jar. In this respect, this episode shows significant aspects that can be used to characterize science, scientific knowledge production, and the nature of science. From our own experimentation, we learned that grounding was not necessary in order to produce the effect. These experiences inspired us to go back to primary sources. In doing so, we came to a new understanding of the early period after Kleist's and Musschenbroek's initial creation of the effect. From our analysis, we conclude that it is not the grounding which was perceived as a major innovation (as well as a challenge) during this early period of the discussion but the concept of an electrical circuit. This understanding was fundamental in characterizing the Leiden jar as a new device challenging the then current knowledge of experimental practices in the field of electricity.

Laminados de guayaba (Psidium guajava L) enriquecidos con inulina y calcio / Guava (Psidium guajava L.) laminates enriched with inulin and calcium

La guayaba (Psidium guajava L.) es una fruta de gran aceptación que puede ser utilizada como vehículo de nutrientes y componentes bioactivos, cualidades atractivas para elaborar alimentos con beneficios a la salud. Por tal motivo, se desarrollaron laminados de guayaba enriquecidos con inulina y calcio. Para elaborar los laminados se preparó un puré con pulpa de guayaba, sacarosa y fructosa en proporción 85:10:5, se adicionó inulina, lactato de calcio, solución de ácido cítrico (30%) y se deshidrató en un secador de bandejas a 60 ºC. Se desarrollaron cuatro formulaciones variando las proporciones de inulina y lactato de calcio. Se evaluó la aceptabilidad global de los laminados con una escala hedónica no estructurada de 10 cm (cero representó “me disgusta mucho”, cinco “indiferente” y diez “me gusta mucho”) y la aceptabilidad de los atributos sensoriales dulzor, acidez, color y dureza al morder con una escala JAR (just-about-right) de 3 puntos. Se evaluaron las características físicas, químicas y nutricionales de los laminados elaborados bajo la formulación seleccionada sensorialmente. La aceptabilidad varió entre 6,6 y 7,2, donde los laminados elaborados con 1,0 g de inulina y 1,0 g de lactato de calcio/100g de pulpa representaron la mejor opción. El producto presentó bajo dulzor, alta acidez y alta dureza al morder, sin embargo, ninguno de los atributos causó desagrado. Los laminados de guayaba aportan calcio y fibra dietaria a la ingesta diaria y representan una opción innovadora con potencial de alimento funcional, útil para diversificar y motivar el consumo de frutas y derivados(AU)

Guava (Psidium guajava L.) laminates enriched with inulin and calcium. Guava (Psidium guajava L.) is a fruit of great acceptance that can be used as vehicle of nutrients and bioactive components, attractive qualities for making products with health benefits. Therefore, guava laminates enriched with inulin and calcium were developed. To elaborate the laminates a puree was prepared with guava pulp, sucrose and fructose in proportion 85:10:5, inulin, calcium lactate and citric acid solution (30%) was added and it was subjected to drying in a tray dehydrator at 60 °C. Four formulations were developed varying the proportions of inulin and calcium lactate. The overall acceptability of laminates was evaluated wih a 10-cm unstructured hedonic scale (zero represented "I dislike much" five "indifferent" and ten "I like") and the acceptability of the sensory attributes sweetness, acidity, color and hardness to bite with a 3-point JAR (just-about-right) scale. Physical, chemical and nutritional characteristics of the laminates produced under the selected treatment were evaluated. Acceptability varied between 6.6 and 7.2, where laminates made with 1.0 g inulin and 1.0 g calcium lactate/ 100g pulp represented the best choice. The product presented low sweetness, high acidity and high hardness to bite, however, none of the attributes caused displeasure. Guava laminates provide calcium and dietary fiber daily intake and represent an innovative option with potential functional food, useful to diversify and encourage consumption of fruits and derivatives(AU)

Redes neurais artificiais aplicadas ao processo de coagulação / Artificial neural networks applied to the coagulation process

A coagulação é uma etapa de tratamento da água, e para tal são realizados ensaios de teste de jarro que permitem determinar a dose necessária dos agentes coagulante e químico de ajuste de pH no processo de coagulação. Contudo, esses ensaios demoram a ser executados, não respondendo em tempo real às mudanças da qualidade da água bruta. Para superar tal limitação, redes neurais artificiais multicamadas foram construídas (e seus pesos sinápticos ajustados), validadas e testadas para predizer a dosagem do hidróxido de sódio e do sulfato de alumínio - utilizados como agentes químico de ajuste de pH e coagulante, respectivamente. Os resultados dos modelos obtidos são compatíveis com os dados experimentais tendo em vista que as incertezas das estimativas estão na mesma ordem de grandeza das faixas indicadas pelos ensaios realizados de testes de jarro ao longo de quase seis anos.

Coagulation is a stage in water treatment and, for this, jar tests are performed, which allows determining the optimal coagulant and alkalizer doses in coagulation process. However, these tests are time-consuming and do not enable real-time responses to changes in raw water quality. To overcome these limitations, artificial multilayer perceptron neural networks were built, trained, validated and tested to predict the aluminum and sodium hydroxide doses - used as coagulant and alkalizer, respectively. The results of these models are encouraging to consider that the estimated uncertainties have the same order of the variation limits magnitude indicated by the jar tests for almost a six-year period.