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The aim of this study was to develop and evaluate the performance of a nonwoven (NT) with cellulosic material from cigarette butts. The NT used as a filtering medium had a diameter of 7 cm, height of 24 cm, a surface area of 528 cm2 and a total volume of 692 cm3. The NT was applied for the filtration of water from a pond. To evaluate NT performance, NT characterization, grammage, absorption capacity and permeability analyzes were performed. The results showed that NT was characterized as a microporous material and presented a good absorption performance (values in the order of 4.01 g g-1 to 4.99 g g-1), weight of 115 g m-2, permeability between 3.787 L m-² h-1 and 3.422 L m-² h-1. The NT developed showed potential for use as a filtering medium for the surface water pre-treatment. In addition to helping to reduce the negative environmental impacts caused by the residues of cigarette butts present in the environment.

This study evaluated the adsorption and enzymatic degradation of azo dyes when using SMS. The laccase present in the SMS was characterised, and the maximum activity was obtained at pH 2, a temperature of 45°C, a Michaelis–Menten constant (Km) of 0.264 mM, and a maximum reaction rate (Vmax) of 117.95 µmol L−1 min−1. The presence of NaCl at 5 mM inhibited enzyme activity while no inhibition was observed by Na2SO4, typically found in textile wastewater. The maximum dye adsorption (57.22%) was achieved at pH 8.0, 25°C, and 100 g L−1 of SMS while the maximum enzymatic degradation (14.18%) was obtained under the same conditions, except at pH 4.0. The enzymes laccase, lignin peroxidase, and manganese peroxidase trapped in the SMS resulted in higher dye discolouration when compared to that extracted with aqueous solution, meaning that SMS has strong adsorption capacity and is a natural immobilisation matrix, which improves the enzymatic degradation of the dyes. Thus, SMS can be used in the treatment of textile effluents for dye removal by simultaneous mechanisms of adsorption and enzymatic degradation, with reduction of environmental impacts for SMS disposal and reduction of the costs associated with commercial enzymes and adsorbents.

The performance of an anoxic-oxic membrane bioreactor electrochemically assisted (A/O-eMBR) was assessed as an alternative for azo dye (Remazol Brilhant Violet -RBV) removal from textile wastewater. The A/O-eMBR was operated under three experimental conditions (runs I, II and III), in which different solids retention time (SRT) (45 and 20 d) and exposure mode to electric current (6´ON/30´OFF and 6´ON/12´OFF) were assessed. The reactor exhibited excellent performance on the decolorization process for all experimental conditions, with average dye removal efficiency ranging from 94.3 to 98.2%. Activity batch assays showed that the dye removal rate (DRR) decreased from 16.8 to 10.2 mg RBV L− 1 h− 1 when the SRT was reduced from 45 to 20 d. a behavior attributed to the lower biomass content under these conditions. When the exposure mode was 6 ON´/ 12´OFF, a more substantial decrease of DRR to 1.5 mg RBV L− 1 h− 1 was noticed, suggesting a possible inhibitory effect on dye removal via biodegradation. By reducing the SRT to 20 d, a worse mixed liquor filterability condition was observed, with a membrane fouling rate (MFR) of 0.979 kPa d− 1. In contrast, the use of electric current to exposure mode of 6 ON´/ 12´OFF resulted in lower membrane fouling propensity, with a MFR of 0.333 kPa d− 1. A more attractive cost-benefit ratio in terms of dye removal was obtained by using the exposure mode of 6´ON/30´OFF, for which the energy demand was estimated at 21.9–22.6 kWh kg dye− 1removed, 92–99% lower than that observed for the mode of 6´ON/12´OFF.

Polyacrylonitrile membranes (PAN) have high stability against chemical agents, making them suitable for a wide range of applications as such Ultrafiltration processes. Ultrafiltration membranes composed of PAN/Superfine powder activated carbon (S-PAC) mixtures can be a good research route, aiming the development of a new separation processes for water treatment. The association of materials to form a single product can have technological and economic advantages in separation processes. In this study, S-PAC impregnated into PAN membranes were prepared, characterized and used, as a case study, to remove diclofenac (DCF) from water. The membranes (PAN/S-PAC) were synthesized with different concentrations of S-PAC (0.2, 0.6, 1.0, 3.0 and 5.0 wt%) by a phase inversion process. The results of the TEM characterizations of the S-PAC indicated the presence of micro and nanoparticles (∼10 nm) and tending to form micrometric clusters. The infrared spectra of the membranes were characteristic of PAN; however, vibrational bands attributed to the S-PAC spectrum were also observed, which indicated an interaction between the materials. The case study showed an increase in the water flux and in the DCF rejection efficiency, for composite membranes (PAN/S-PAC) with higher concentration of S-PAC. The results of static adsorption tests indicated that the mechanism of DCF rejection occurred predominantly by adsorption. There were indications that the PAN/S-PAC membranes formed a composite material and the PAN/S-PAC (3.0) presented the best study composition given the results. Although the research is in its initial phase, the results indicated that the composition can improve many water treatment systems.

O carreamento para corpos hídricos de efluentes ácidos contendo compostos oxidados de ferro e enxofre, oriundos da mineração de carvão, constitui a drenagem ácida de minas (DAM) que leva à degradação da qualidade da água. Trabalhos recentes mostram possibilidades no tratamento conjunto de DAM com outros efluentes, devido à capacidade coagulante da mistura. O objetivo deste trabalho foi avaliar o tratamento integrado de DAM e efluente têxtil seguido por processo oxidativo avançado foto-Fenton, utilizando o próprio ferro presente na DAM para o processo de oxidação. Verificou-se que a proporção de mistura em que houve efeito de coagulação foi de 13:7 (650 mL de DAM e 350 mL de efluente têxtil). O processo conjugado obteve eficiências de remoção de 99% para cor, 99% para turbidez, 91% para carbono orgânico dissolvido (COD), 95% para compostos aromáticos, 99% para sólidos totais e 83% para sólidos suspensos, mostrando ser efetivo no tratamento do efluente da indústria têxtil.

O presente estudo teve como objetivo avaliar a tratabilidade e a toxicidade de efluente têxtil submetido ao processo Foto-Fenton heterogêneo utilizando sementes de alface (Lactuca sativa) como organismos-teste. As amostras de efluentes foram coletadas na ETE de uma indústria têxtil e submetidas ao tratamento oxidativo, que teve duração de 105 minutos. Em intervalos de tempo (15, 30, 45, 60, 75, 90 e 105 minutos), alíquotas foram retiradas para análises da toxicidade e para análises físico-químicas (cor, compostos aromáticos, turbidez, nível de pH e peróxido residual). As respostas da toxicidade foram avaliadas a partir dos resultados do percentual de germinação e da inibição de crescimento da radícula e do hipocótilo da planta. A taxa média de germinação absoluta após o tratamento foi de 72,5%. Uma inibição de 30,6% do hipocótilo e de 99% da radícula foi observada. Em relação aos parâmetros físico-químicos, o processo foto-Fenton heterogêneo foi efetivo, apresentando uma remoção de cor de 90%, dos compostos aromáticos de 80 % e da turbidez de 30%.

Devido, muitas vezes, à ineficiência dos processos de tratamento convencionais de efluentes têxteis utilizados pelas indústrias, a eletrocoagulação (EC) surge como alternativa. Neste contexto, o presente trabalho tem como objetivo encontrar a melhor configuração de um reator eletroquímico, por meio de um planejamento fatorial 2³, tendo como respostas a remoção de cor e de compostos aromáticos. Para isso, foram realizados ensaios em reator de bancada com capacidade de 1,1 L, e eletrodos de alumínio conectados a uma fonte de corrente contínua com variação de 0-10A e 0-30V. As melhores eficiências foram alcançadas em pH 3, distância entre as placas de 3 cm e densidade de corrente de 200 A.m-2. Em 15 minutos de tratamento atingiu-se remoção de 92%, 82%, 82% e 64% para os parâmetros cor, compostos aromáticos, turbidez e carbono orgânico dissolvido (COD), respectivamente.

This study aimed to evaluate a nonwoven (NW) production and performance from cellulose acetate fiber from cigarette butts andapplied to a filtration system for surface water pre-treatment. The system had a surface area of 528 cm2, cellulose acetate from cigarette butt as filter media, was used and was fed with surface water from a pond. In order to evaluate the treatment performance of the filtration system were evaluated in the raw water (RW) and the filtered water (FW) the classical parameter of water quality as turbidity, total suspended solids (TSS), apparent color, true color, and total organic carbon (TOC) and heavy metals (iron, copper, and cadmium). Moreover, the presence of nicotine was investigated in the FW. The results showed a mean removal efficiency in order to 62.01%, 54.42%, 50.36 %, 6.73%, and 5.20% for turbidity, TSS, apparent color, true color, and TOC, respectively. The removal of metals varied in the order of 72.26%, 9.61%, and 2.12% for cadmium, iron, and copper, respectively. The presence of nicotine in RW and FW was not identified. In this way, besides reducing the negative environmental impacts caused by cigarette butts present in the environment, the developed technology showed potential for removing pollutants present in surface waters.

The objective of this study is to obtain a more detailed assessment of particles that contain rare-earth elements (REEs) in abandoned deposits of Brazilian fine coal tailings (BFCTs), so as to aid current coal mining industries in the identification of methodologies for extracting such elements (Santa Catarina State, Brazil). The BFCT areas were sampled for traditional mineralogical analysis by X-ray Diffraction, Raman Spectroscopy and nanomineralogy by a dual beam focused ion beam (FIB) coupled with field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM) coupled with an energy dispersive X-ray microanalysis system (EDS). The results show that the smaller the sampled coal fines were, the higher the proportion of rare-earth elements they contained. Although the concentration of REEs is below what would normally be considered an economic grade, the fact that these deposits are already ground and close to the surface negate the need for mining (only uncovering). This makes it significantly easier for REEs to be extracted. In addition, owing to their proximity to road and rail transport in the regions under study, the opportunity exists for such resources (BFCTs) to be utilized as a secondary market as opposed to simply being discarded as has been done in the past.

A indústria têxtil desempenha papel vital para o desenvolvimento econômico de muitos países. No entanto, a descarga de seus efluentes no meio ambiente causa considerável poluição dos corpos receptores e sérios fatores de risco à saúde. Em geral, o tratamento convencional não degrada totalmente seus poluentes. Então, novos métodos de tratamento vêm sendo estudados na última década, destacando- -se a eletrocoagulação. O presente trabalho objetivou avaliar a otimização do processo da eletrocoagulação aplicado em efluente têxtil sintético, a fim de investigar o efeito da intensidade de corrente e do pH com relação à remoção da cor. Os resultados revelaram o potencial da aplicação do processo com valores de intensidade de corrente de 33A e pH inicial 3, expondo remoção de cor na ordem de 95%. O tempo de eletrólise estabelecido em 30 minutos contribuiu para a efetividade do processo no tratamento do efluente têxtil sintético e demostrou capacidade para aplicação em efluentes em escala real.

RESUMO Neste trabalho foi avaliado o processo foto-Fenton solar mediado por ferrioxalato como tratamento primário de um efluente têxtil bruto (E1) e como um processo de polimento, após processo de lodos ativados (E2). Por um ano, ao menos uma vez por mês, a eficiência de descoloração e o comportamento dos sólidos foram avaliados sob condições naturais de radiação, temperatura e características dos efluentes. As condições operacionais foram as seguintes: 50 mg L-1 de ferro, pH 5, 525 mg L-1 de H2O2, administrados em dosagens decrescentes. O oxalato foi adicionado na razão molar de 1:3 [Fe+3:(C2O4)-2]. A descoloração máxima de E1 foi de 67% para intensidade de radiação de 690 W m-2; já a de E2 foi de 95% para intensidade de 620 W m-2. Houve considerável aumento na turbidez e nos sólidos suspensos em função da precipitação do ferro e de sua ação coagulante. A degradação do complexante durante o processo no E2 em dias ensolarados provocou elevada sedimentabilidade dos sólidos do efluente final, resultando em um sobrenadante clarificado, o que não ocorreu em dias nublados.

O presente trabalho consistiu na aplicação da metodologia de avaliação de custo de ciclo de vida para estimar os custos de operação de um biorreator a membrana hipotético projetado para ser implementado em Santa Catarina/Brasil, visando à produção de água de reúso. Foram levantados dados de custo referentes à aquisição e troca de membranas, consumo energético, disposição final de lodo e funcionários para um biorreator a membrana dimensionado para tratar 6.060 m³d-1 (50.000 hab). Foram estimados valores equivalentes a R$0,63/m³ ou R$2,10 por kg de DBO removida, os quais vão ao encontro de outros estudos realizados abordando custos de biorreatores a membrana. O sistema proposto se apresentou competitivo para produzir água de reúso, apresentando custo de tratamento (R$/m³) inferior ao valor cobrado pela água potável.

In the Coal Minning Region of Santa Catarina is located the largest pole producing ceramic floors in Brazil. Considering the large volume of alkali feldspar rich waste that is generated during the porcelain polishing step. The ceramic industry is great generator of solid waste, usually deposited in landfills, being responsible for the pollution of extensive areas. There is a great availability of this alkaline material that can potentially be used as a neutralizing agent to prevent the generation of AMD in the coal minning. In this work the characterization of the potential of the generation of DAM through static and kinetic tests of a coal waste obtained in a beneficiation plant of the coal minning region, was characterized chemically the waste originated during the step of polishing in the production of porcelain tiles and determined the neutralization potential of the alkali feldspar waste. The results indicate that the coal mining waste presents a high potential of acidity (AP), the waste of the production of porcelanates presents as a major component of its composition silicon oxide and aluminum oxide, but also other oxides such as of potassium and has a moderate neutralization potential (NP). The results indicate a moderate potential of use as an alkaline additive in the prevention of AMD generation. However other uses are recommended, such as the production of soil-cement with this waste.

This work aimed to remove sulfate and acidity from mine-impacted water (MIW) via electrocoagulation (EC), a technique which stands as an advanced alternative to chemical coagulation in pollutant removal from wastewaters. The multiple electrochemical reactions occurring in the aluminum anode and the stainless steel cathode surfaces can form unstable flakes of metal hydroxysulfate complexes, causing coagulation, flocculation, and floatation; or, adsorption of sulfate on sorbents originated from the electrochemical process can occur, depending on pH value. Batch experiments in the continuous mode of exposition using different current densities (35, 50, and 65 A m-2) were tested, and a statistical difference between their sulfate removals was detected. Furthermore, the intermittent mode of exposure was also tested by performing a 22-factorial design to verify the combination with different current densities, concluding that better efficiencies of sulfate removal were obtained in the continuous mode of exposition, even with lower current densities. After 5 h of electrocoagulation, sulfate could be removed from MIW with a mean efficiency of 70.95% (in continuous mode of exposition and 65 A m-2 current density), and this sulfate removal follows probable third-order decay kinetics in accordance with the quick drop in sulfate concentration until 3 h of exposure time, remaining virtually constant at longer times. Graphical abstract.

Desafios econômicos e ecológicos procedentes da crise hídrica e das restrições impostas pela legislação ambiental contribuíram recentemente para a expansão das aplicações dos processos oxidativos avançados como técnicas alternativas de tratamento de efluentes. O presente trabalho objetivou avaliar o processo UV/H2 O2 aplicado como pós-tratamento de águas residuárias da indústria de papel e celulose, sob diferentes concentrações de oxidante. Os resultados revelaram o potencial da aplicação do processo UV/ H2 O2 na oxidação de substâncias orgânicas com remoção da DBO5 de 85 a 92%. A remoção da cor foi total para todas as concentrações de H2 O2 . Para a turbidez, os índices de remoção variaram entre 41 e 83%. Na remoção dos compostos aromáticos, o processo reduziu em até 98% a aromaticidade do efluente, mostrando assim a efetividade do processo no tratamento dos efluentes da indústria de papel e celulose.

This study investigates the effects of pH, H2O2 concentration and reaction time of the UV/H2O2 photochemical process on the removal of organic matter and ammonia from biologically pre-treated landfill leachates in anaerobic stabilization ponds. The results show that the concentration of H2O2 and the initial pH are significant factors, with no significant interaction between them. A pH of 3 is the optimum value for the UV/H2O2 process for the removal of organic matter, resulting in 51.63% chemical oxygen demand (COD) removal in addition to the removal of aromatic compounds. The N-NH3 removal showed little variation between pH values of 1, 5, 7, 11 and 13; the removal was on the order of 16.43 ± 2.00%. The consumption of H2O2 was elevated at pH 9, 11 and 13; at these pH values, the average removal was 94.56 ± 0.43%, compared to 43.07% at pH 3. First-order polynomial models and reaction times on the order of 15 min are sufficient for optimization studies and for evaluation of the effects of the studi...

A new activated biochar was produced by carbonizing Cássia fistula L. leaves and its characterization was performed. Scanning Electron Microscopic (SEM) images of the activated biochar showed morphology with numerous irregular cavities and pores. BET surface area and total pore volume of produced adsorbent were 192 m².g-1 and 0.108 cm3.g-1, respectively. Mean porous diameter of the produced biochar was 2.263 nm, characterizing a mesoporous material. Crystallinity and functional groups of the adsorbent were determined by X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy analyses, respectively. The pH of zero charge point (pHzcp) observed was equal to 10, demonstrating that the activated biochar has a negative surface, which facilitates the adsorption of positively charged compounds in water and wastewater treatment. Tree leaves of Cássia fistula L. represent a promising raw material for activated biochar production, given their availability and characteristics of the adsorbent produced. The use of tree leaves for activated biochar production can reduce the operational costs of adsorption process, besides providing the use of a residue for a more noble purpose.

O presente estudo teve como objetivo avaliar a aplicacao de duas diferentes granulometrias de lodo provenientes de Estacao de Tratamento de Agua (ETA) rico em aluminio (lodo fino com particulas de diâmetro inferior a 0.1mm e lodo grosso com particulas de diâmetro entre 0.1 e 0.6mm), como material adsorvente na remocao de fosfatos de efluentes previamente tratados em wetlands construidos. Para isso, foram realizados ensaios cineticos e isotermicos em batelada e colunas de leito fixo. Os ensaios cineticos, realizados com dosagem de adsorvente de 20 g.L -1 , e concentracao de adsorvato de 12.5 mgPO 4 3- L -1 , resultaram em uma remocao superior para o lodo de menor granulometria, atingindo 90% de eficiencia e uma concentracao de equilibrio de 1.2 mgPO 4 3- L -1 . Os ensaios isotermicos, conduzidos com diferentes massas de adsorvente (0.5; 0.75; 1.0; 1.5; 2.0 e 3.0 g) alcancaram as capacidades maximas de adsorcao de 1.36 e 1.33 mgPO 4 3- g -1 para o lodo fino e lodo grosso, respectivamente. As colunas de leito fixo apresentaram elevadas capacidades de adsorcao, para os diferentes fluxos 5.0 e 2.0 mL.min -1 , alcancando entre 0.76-3.65 mgPO 4 3- g -1 para o lodo grosso e 8.73-12.49 mgPO 4 3- g -1 , para o lodo mais fino. Os resultados desse estudo evidenciam que as particulas de menor granulometria resultaram em um melhor processo de adsorcao, levando a uma remocao mais rapida do fosforo dissolvido, e tambem a uma menor concentracao de equilibrio. Desse modo, o uso do lodo nao apenas prove uma solucao tecnologica de baixo custo para o tratamento de efluentes, mas tambem uma opcao de gestao efetiva desse residuo nas estacoes de tratamento de agua.

This paper comprises several assays aiming to identify the basis for the bioremediation of mine-impacted water (MIW). To do so, the conditions for build anoxic microcosms for treating this effluent were varied, containing MIW, and a source of chitin, to biostimulate sulfate-reducing bacteria (SRB). The chitin sources were: commercial chitin (CHIT) and shrimp shell (SS), which in addition to chitin, contains CaCO3, and proteins in its composition. The CHIT assays were not successful in sulfate-reduction, even when the pH was increased with CaCO3. However, in all SS assays the SRB development was successful (85% sulfate removal for assay 3), including the metal-free (MF-SS) assay (75% for assay 5). High-throughput sequencing analysis revealed the structure of bacterial community in the SS assay: the most abundant genera were Clostridium and Klebsiella, both fermentative and chitinase producers; a few SRB from the genera Desulfovibrio and Desulfosporosinus were also detected. In the MF-SS assay, Desulfovibrio genuswas detected but Comamonas was dominant. It could be deduced that SS is a suitable substrate for SRB development, but CHIT is not. The sulfate-reduction process was provided by the cooperation between fermentative/chitinase-producer bacteria together with SRB, which leads to efficient MIW treatment, removing sulfate and metallic ions.

Among the Advanced Oxidative Processes (AOPs) applied in the degradation of toxic and resistant organic compounds such as dyes, the heterogeneous photo-Fenton process stands out, once it has high discoloration efficiency and operational simplicity. Given that, this study evaluated the efficiency of the heterogeneous photo-Fenton process in real textile wastewater treatment using chitosan beads as a solid catalyst. Laboratory-scale beads production and tests were carried out to monitor a photochemical reactor equipped with a mercury bulb of 125 W. Samples were collected at different reaction times, equal to 15, 30, 45, 60, 75, 90, and 105 min. The H2O2 concentration applied was 400 mg L−1. The chitosan beads weighed 2 g and were coated with iron, presenting an average diameter of approximately 4 mm. The results presented 91.92 % of effluent discoloration. It was possible to verify the process efficiency without iron precipitation when working with pH values above 6. Furthermore, the determination of other parameters behaviors, such as color, aromatic compounds, dissolved and total solids, as well as toxicity, was accomplished.

Iron and manganese removal is made conventionally by oxidation methods; however, when aquatic humic substances (HS) are present, they can affect the removal, with another treatment process being necessary. This study focused on performance of ultrafiltration (UF) and nanofiltration (NF), preceded by coagulation, flocculation, and sedimentation stages for iron, manganese, and HS removal, with two water sources that present superior levels of humic compounds, and measured by dissolved organic carbon (DOC) and UV absorbance at 254 nm. Coagulation, flocculation, and sedimentation combined with UF/NF efficiently removed dissolved iron, HS, apparent color, and turbidity. Almost total iron removal was already attained in the prior steps of coagulation, flocculation, and sedimentation, obtaining final values of dissolved iron of less than 0.001 mg L−1 for the two types of water studied. However, the complete system did not appear effective (less than 50% efficiency) in dissolved manganese removal, althoug...

This study investigates the effects of pH, H

In this work, zeolite, Controll M.F. 574® was characterized and its adsorption properties were evaluated for the removal of iron (Fe) and manganese (Mn) from natural water, compared with a synthetic solution. Characterization by dispersive X-ray and X-ray diffraction identified a semi-crystalline structure and the presence of magnesium aluminium silicate, quartz and iron and manganese oxides. The results of the adsorption isotherms verified that the adsorption of iron followed a linear model indicating that physisorption occurred. The adsorption of manganese was better adjusted to the Langmuir model, indicating the formation of a monolayer on the surface of the adsorbent. The kinetic results were best adjusted to the pseudo-second-order model with a correlation coefficient of 0.99 for adsorption of both elements. The results showed that the zeolite studies showed good adsorption capacity for Fe (74%) and Mn (66%) in natural water. The concentrations of these metals were below the values permitted ...

The removal of filamentous cyanobacteria in natural water was investigated by a sequential treatment involving dissolved air flotation (DAF) (preceded by coagulation/flocculation) and microfiltration (MF) technologies. The combined treatment was considered to evaluate the contribution of the DAF process as a pre-treatment for MF to mitigate the impact on the microfiltration performance caused by the presence of the cells. The bench-scale experiments were conducted with surface water samples. For C/F steps, a dose of 40 mg L−1 of aluminium sulphate was used, and several operational conditions were adopted for the DAF tests. For the MF experiments, polyvinylidene fluoride (PVDF) membranes (0.3 μm) and a working pressure of 1 bar were used. The parameters colour, turbidity, UV254 nm absorbance, DOC and cyanobacterial density, were evaluated. The DAF-MF sequence showed a considerable reduction in the residual values for all parameters compared with the DAF process alone. MF was able to remove cyanoba...

In this work, an adsorbent coal was characterized and its sorption properties for the removal of iron and manganese from aqueous solutions were determined. Energy dispersive X-ray (EDX) analysis and X-ray diffraction (XRD) identified the presence of quartz, magnetite and manganese oxide in the adsorbent coal. The results of the adsorption isotherms verified the adsorption of iron and manganese by adsorbent coal showing a linear behaviour and indicated that chemisorption and physisorption occurred. The kinetic results were best adjusted to the pseudo-second order model with a 0.999 correlation coefficient. The results showed that the adsorbent coal could be used efficiently for the removal of iron and manganese from aqueous solutions.

Resumo A drenagem ácida mineral (DAM) é um dos mais graves impactos ambientais da mineração. Cursos de água impactados pela DAM são avaliados como impróprios acarretando graves impactos ambientais e problemas socioeconômicos severos. Este estudo visa identificar o potencial de um resíduo, casca de camarão, como fonte de quitina e alcalinidade para remediação de águas contaminadas por DAM visando seu posterior reuso para fins secundários não potáveis. Foram efetuados ensaios com a casca de camarão, diferenciando entre corpo (CR) e cabeça (CB), e quitina comercial (QT, 70% de pureza), para o tratamento de amostras de água superficiais e subterrâneas impactadas da Região Carbonífera Catarinense/SC (Brasil). Realizaram-se ensaios em duplicata e em regime de batelada variando o teor de substrato, tempo de contato e velocidade de agitação. Conseguiu-se a remoção quase total de Fe (>92%) e Al (>99%) e uma remoção de Mn entre 40-60%. CR apresentou os melhores resultados após 48h de tratamento com 200 rpm e 10 gL–1de substrato. O aumento no pH foi mais significativo nas amostras contendo CR, passando o pH de ~3 para ~7. Os resultados indicaram o potencial da utilização direta da casca de camarão para o tratamento de efluentes para reuso secundário não potável. Abstract The mineral acid mine drainage (AMD) is one of the most serious environmental impacts of mining. Watercourses impacted by DAM are assessed as unfit, causing serious environmental consequences and severe socioeconomic problems. The main objective of the present study is to evaluate the potential of a residue, shrimp-shell, as source of chitin and alkalinity for remediation of mine-impacted water (MIW), seeking their subsequent reuse for secondary non-potable reuse. Comparative tests with the shrimp-shells were performed, differentiating between body (CR) and head (CB), and commercial chitin (QT 70% purity), with samples of surface water and groundwater from the impacted “Região Carbonífera Catarinense” (Brazil). Assays were performed in batch-microcosms with different concentrations of substrate, contact time and stirring speed. Metals were almost removed [Fe (> 92%), Al (> 99%), and Mn (40-60%)]. CR showed the best results after 48 hours of treatment with 200 rpm and 10 g L–1 of substrate. The higher increase in pH was in the samples with CR, from ~ 3 to ~ 7. The results indicated the potential of direct use of shrimp shells to treat effluents for secondary non-potable reuse.

A desinfecção dos esgotos deve ser considerada quando se pretende reduzir os riscos de transmissão de doenças infecto-contagiosas. Nesse sentido, os requisitos de qualidade de uma água devem ser avaliados em função dos usos previstos para a mesma. O dióxido de cloro (ClO2) possui excelentes propriedades bactericidas, virucidas, esporocidas e algicidas e, devido a isso, é usado como desinfetante de água de abastecimento e efluente doméstico, bem como inibidor de crescimento de algas. O objetivo do trabalho foi estudar a melhor dosagem para uma boa desinfecção de efluentes sanitários previamente tratados mediante lodos ativados por aeração prolongada, avaliar a inativação de coliformes e o residual de dióxido de cloro remanescente. Foram realizados ensaios para diferentes dosagens de dióxido de cloro e diferentes tempos de contato. Os resultados obtidos mostraram que a dosagem mais indicada para desinfecção do efluente estudado foi 2,0 mg ClO2/L com um tempo de contato de 20 minutos, condições sob as quais é atingido 100% de remoção de coliformes fecais e oxidada parcialmente a matéria orgânica remanescente, em tanto que os valores de pH e residual de ClO2 do efluente mantêm-se dentro dos admitidos pelas normativas brasileira e estadunidense em vigor. O estudo econômico levado a cabo permitiu concluir que a desinfecção de efluente doméstico mediante dióxido de cloro pode ser economicamente viável.Disinfection of sewage must be considered when reduction of infect-contagious disease transmission risks is intended. Thus, water quality requirements have to be evaluated in function of its predetermined uses. Chlorine dioxide (ClO2) has excellent bactericide, viruscide, sporicide and algaecide properties and, by these reasons, it is used as a disinfectant for drinking water and municipal sewage and as an algal growing inhibitor. The objective of this work was to investigate the most adequate ClO2 doses for an adequate disinfection of municipal sewage previously treated by an activate sludge with extended aeration process, evaluating the fecal coliform inactivation and the remaining residual chlorine dioxide. Essays were carried out for different ClO2 doses and different contact times. The results showed that the most adequate dose for sewage disinfection was 2,0 mg ClO2/L in 20 min of contact time. Under this condition, 100% coliform removal is attained, the remaining organic matter is partially oxidized and pH and residual ClO2 values of effluent are maintained in the range determined by the Brazilian and USA regulations. It was concluded, from the economical study carried out, that disinfection of municipal sewage using chlorine dioxide is economically viable.

A desinfecção dos esgotos deve ser considerada quando se pretende reduzir os riscos de transmissão de doenças infecto-contagiosas. Nesse sentido, os requisitos de qualidade de uma água devem ser avaliados em função dos usos previstos para a mesma. O dióxido de cloro (ClO2) possui excelentes propriedades bactericidas, virucidas, esporocidas e algicidas e, devido a isso, é usado como desinfetante de água de abastecimento e efluente doméstico, bem como inibidor de crescimento de algas. O objetivo do trabalho foi estudar a melhor dosagem para uma boa desinfecção de efluentes sanitários previamente tratados mediante lodos ativados por aeração prolongada, avaliar a inativação de coliformes e o residual de dióxido de cloro remanescente. Foram realizados ensaios para diferentes dosagens de dióxido de cloro e diferentes tempos de contato. Os resultados obtidos mostraram que a dosagem mais indicada para desinfecção do efluente estudado foi 2,0 mg ClO2/L com um tempo de contato de 20 minutos, condições sob as quais é atingido 100% de remoção de coliformes fecais e oxidada parcialmente a matéria orgânica remanescente, em tanto que os valores de pH e residual de ClO2 do efluente mantêm-se dentro dos admitidos pelas normativas brasileira e estadunidense em vigor. O estudo econômico levado a cabo permitiu concluir que a desinfecção de efluente doméstico mediante dióxido de cloro pode ser economicamente viável.

This study has investigated the reduction in coloured substances and toxic compounds present in textile industry effluent by the use of an advanced oxidation process using hydrogen peroxide (H2O2) as oxidant, activated by ultraviolet radiation. The investigation was carried out on industrial effluents, both raw and after biological treatment, using different concentrations of H2O2 in a photochemical reactor equipped with a 250 W high-pressure mercury vapour lamp. The results showed that after 60 minutes of ultraviolet irradiation a H2O2 concentration of 500 mg L(-1) was able to remove approximately 73% of the coloured compounds present in raw effluent and 96% of those present in biologically treated effluent. Additionally, post-treatment toxicity tests performed using the microcrustacean Daphnia magna showed a significant effective reduction in the acute toxicity of the raw effluent. In tests carried out with treatment at a concentration of 750 and 1000 mg L(-1) H2O2, analysis of the frequency ofmicronuclei in erythrocytes of Tilapia cf rendalli exposed to treated effluent samples confirmed that there were no mutagenic effects on the fish. Together, these results indicate that the oxidation process offers a good alternative for the removal of colour and toxicity from textile industry effluent.

Paper aims The purpose of the study is to present a proposal for implementation of Voluntary Delivery Points (VDP) of expanded polystyrene (EPS) in Florianópolis city, Brazil. Originality Transportation, uncertainty of financial return, and lack of population's awareness are barriers for EPS recycling. This paper seeks to overcome these difficulties to give a better destination for EPS other than landfill. A method is proposed for the implementation of VDP to receive this type of waste. As far as the authors know, no previous research has proposed this analysis for Styrofoam® RL. Research method The research method consists of a survey application with the population and spatial analysis using heat maps of the public equipment on QGIS® software. Main findings It was possible to verify the generation capability of EPS waste in Florianópolis, the lack of population’s awareness about EPS recycling, and suitable points for the implementation of VDP to aid in the RL. Implications for theory and practice This paper seeks to encourage researchers and practitioners to develop solutions for EPS RL. The main contribution of this article is presenting a practical alternative method that aims to overcome one of the main barriers of EPS RL, which is low-density waste transportation, dealing with consumer's responsibility for the waste generated, their awareness on the issue and their active contribution to a proper destination of EPS waste.