A presente pesquisa teve por objetivo avaliar a produção biológica de hidrogênio em longo prazo, e os impactos da separação das principais etapas da digestão anaeróbia, acidogênese e metanogênese, sobre a eficiência do tratamento em reatores de leito fixo estruturado e sobre o desempenho da filtração em biorreatores com membrana. O efluente utilizado foi à base de sacarose e a temperatura foi mantida em 30ºC. Na primeira etapa experimental, avaliou-se a produção de H2 em três configurações de reatores: leito fixo estruturado (FB), UASB granular (UG) e UASB floculento (UF-1). Na segunda etapa experimental, um reator UASB acidogênico (UF-2) foi combinado a um reator metanogênico de leito fixo estruturado (RM). Um reator de estágio único de leito fixo estruturado (RU) foi operado em paralelo. Na última etapa experimental, foram avaliados dois biorreatores anaeróbios conjugados com módulos externos de membranas tubulares, nomeadamente 1-AnMBR, que foi alimentado com efluente bruto, e 2-AnMBR, que foi alimentado com efluente acidificado. Na primeira etapa, sob um TDH de 3,3 h (COV = 33 gDQO.L-1d-1), os reatores FB, UG e UF-1 apresentaram produção de H2 contínua, porém instável, com rendimentos de aprox. 1,5, 0,8 e 1,2 molH2.mol-1sacaroseconsumida, respectivamente. O reator UF-1 apresentou uma estabilidade relativamente melhor e, por isso, esta configuração foi utilizada nos experimentos seguintes. No reator UF-2, aumentou-se o TDH para 4,6 h (COV = 25 gDQO.L-1d-1), o que significativamente promoveu a melhoria do desempenho. Nenhum alcalinizante foi adicionado e o pH do efluente permaneceu em torno de apenas 2,7. Contudo, uma produção de H2 contínua, estável e por longa duração foi atingida, de 175 mLH2.L-1h-1 (= 4,2 LH2.L-1d-1), com rendimento de 3,4 molH2.mol-1sacaroseconsumida, concomitante com a produção de ácido acético e etanol. Nos reatores metanogênicos, o TDH aplicado foi gradativamente reduzido (53-18 h no RM e 56-23 h no RU). Após os sistemas atingirem estabilidade, os valores de DQO permaneceram inferiores no efluente do RM, sobretudo pela redução da concentração de SSV, equivalente a 92 mg.L-1, enquanto que no RU essa concentração foi de 244 mg.L-1. No final da operação, o rendimento energético do sistema de dois estágios foi de 20,69 kJ.g-1DQOadicionada, sendo 90% proveniente do CH4 e 10% do H2. Este rendimento foi 34% maior do que o obtido no reator de estágio único, que foi de 15,48 kJ.g-1DQOadicionada. Por fim, avaliando-se o desempenho da filtração nos biorreatores com membrana, verificou-se que a permeabilidade operacional foi, na maior parte do tempo, superior no 2-AnMBR. A pré-acidificação do efluente levou à redução de cerca de 56-59% na concentração de sólidos voláteis suspensos e totais no 2-AnMBR e à modificação no perfil do tamanho das partículas. No 1-AnMBR, porém, não havia partículas de pequenas dimensões, tais quais encontradas no reator acidogênico, indicando reduzido crescimento suspenso de bactérias acidogênicas. Embora os valores de fluxo crítico tenham sido muito semelhantes para ambos os AnMBR, testes de resistência específica da torta indicaram maior resistência do lodo do 1-AnMBR (1,02 x 1018 m-1), comparado ao lodo do 2-AnMBR (1,03 x 1012 m-1) e ao lodo acidogênico (7,44 x 1011 m-1). Portanto, essa pesquisa demonstrou, por meio da aplicação do tratamento anaeróbio em dois estágios, a viabilidade da produção contínua de hidrogênio em pH extremamente ácido e com mínimos requerimentos operacionais, a redução da concentração de sólidos suspensos no efluente de reatores de leito fixo estruturado, o potencial de aumento da recuperação de bioenergia e de redução da incrustação em membranas de ultrafiltração. / This study assessed long-term hydrogen production and the impacts of separating the main stages of anaerobic digestion (acidogenesis and methanogenesis) on treatment efficiency in structured fixed-bed reactors and on filtration performance in anaerobic membrane bioreactors. Sucrose based wastewater was used and the temperature was maintained at 30°C. In the first experimental phase, H2 production was evaluated in three different acidogenic reactors: structured fixed-bed (FB), granular UASB (UG) and flocculated UASB (UF-1). In the second experimental phase, an acidogenic UASB reactor (UF-2) was combined with a structured fixedbed methanogenic reactor (RM). A single-stage structured fixed-bed reactor (RU) was operated in parallel. In the last experimental phase, two sidestream anaerobic membrane bioreactors were evaluated: 1-AnMBR, which was fed with raw effluent; and, 2-AnMBR, which was fed with biologically acidified effluent. During the first operational phase, under an HRT of 3.3 h (OLR = 33 gCOD.L-1d-1), the FB, UG and UF-1 reactors showed continuous but unstable H2 production, with yields of approximately 1.5, 0.8 and 1.2 molH2.mol-1sucroseconsumed, respectively. The UF-1 reactor showed relatively better stability; therefore, this configuration was used in the next experiments. In the UF-2 reactor, the HRT was increased to 4.6 h (OLR = 25 gCOD.L-1d-1), which significantly improved the overall performance. No alkalizing agent was added, and effluent pH values remained around only 2.7. However, continuous, stable and long-term H2 production was achieved of 175 mLH2.L-1h-1 (= 4.2 LH2.L-1h-1), with yields of 3.4 molH2.mol-1sucroseconsumed, concomitant with acetic acid and ethanol production. In the methanogenic reactors, the HRT was gradually reduced and, when the systems reached stability, COD values remained lower in the RM effluent. This was mainly due to the reduction of VSS concentrations, equivalent to 92 mg.L-1, while in the RU this value was 244 mg.L-1. At the end of the operation, the energy yield of the two-stage system was 20.69 kJ.g-1CODadded with 90% coming from CH4 and 10% from H2. This yield was 34% greater than that obtained in the single-stage system, which was 15.48 kJ.g-1CODadded. Finally, regarding the filtration performance in the membrane bioreactors, the operational permeability was higher in the 2- AnMBR most of the time. The pre-acidification of the effluent led to the 56-59% reduction in the volatile total and suspended solid concentrations, and to modification in the particle size profile in the 2-AnMBR. Nevertheless, in the 1-AnMBR, there were no small particles such as were found in the sludge of the acidogenic reactor, indicating less suspended growth of acidogenic biomass. Although the critical flux values were very similar for both AnMBRs, a higher specific cake resistance was verified in the 1-AnMBR sludge (1.02 x 1018 m-1), as compared to the 2-AnMBR sludge (1.03 x 1012 m-1) and to the acidogenic sludge (7.44 x 1011m-1</sup). Therefore, this study demonstrated, through the application of two-stage anaerobic treatment, the viability of continuous hydrogen production in extreme acid pH and with minimum operating requirements, the reduction of solid concentrations in the effluent of structured fixed bed reactors, as well as the potential for increased bioenergy recovery and for fouling reduction of ultrafiltration membranes.

Anaerobic digestion (AD) is becoming a widely adopted technology for conversion of organic waste and nutrient-rich fertiliser production due to its cost-effectiveness and sustainability. In this study, a batch experiment was conducted using five different types of food waste and cow dung (CD). No significant difference was observed among the four substrates that produced the highest methane (P<0.05). Based on the batch experiment results, two substrates were selected for semi-continuous digestion and the highest methane yield (67%) was obtained from co-digestion (CO). PCR-DGGE results revealed higher bacterial and archaeal diversity indices in CO as compared to mono-digestion of CD and mixed food waste. The high-throughput sequence analyses revealed that the Operational Taxonomic Units (OTUs) belonging to the phyla Bacteroidetes, followed by Firmicutes, Actinobacteria and Proteobacteria, were dominant in all treatments. The enhanced methane production in CO could be attributed to the neutral pH and partial shift of archaea from Methanosaeta to Methanosarcina. The digestate and fresh CD were screened for plant growth promoting bacteria (PGPB), nutrient and heavy metal content. The dung contained higher concentrations of heavy metals (P<0.05) and potential pathogens in comparison to the digestate. The use of digestate may, therefore, enhance soil fertility with minimal negative environmental effects. / School of Agriculture and Life Sciences / M. Sc. (Life Sciences)

Este trabalho teve por objetivo investigar a degradação de lipídios em três sistemas anaeróbios de tratamento: um reator anaeróbio de fluxo horizontal de leito fixo (RAHLF) , um sistema combinado composto por um reator enzimático de leito expandido invertido (RELI) seguido por um RAHLF e um reator anaeróbio de manta de lodo (UASB). Os sistemas foram monitorados em uma câmara com temperatura controlada a 30,0 ± 0,5°C e alimentados com substrato sintético a base de lipídios, com concentração, em termos de demanda química de oxigênio (DQO) de 8748 ± 711 mg/L e concentração de óleos e graxas de 1820 ± 512 mg/L, O reator RAHLF foi operado com tempo de detenção hidráulica (TDH) de 24 horas por 100 dias e apresentou eficiências médias de remoção de DQO e de lipídios de 98,9 ± 0,4% e 94,9 ± 3,2%, respectivamente. O sistema combinado (reator enzimático / reator anaeróbio) apresentou eficiências médias de remoção de DQO e de lipídios de 99,0 ± 0,3% e 94,2 ± 2,8%, respectivamente, operado com TDH de 30 min no reator enzimático e 24 h no reator microbiológico. Posteriormente, o reator RAHLF foi submetido à diminuição do TDH de 24 para 8 h. As eficiências médias de remoção de DQO e lipídios foram de 87,0 ± 3,2% e 90,5 ± 2,7% verificadas para o menor TDH aplicado (8 h). O modelo cinético baseado em reações paralelas e em série, de primeira ordem, indicaram que a velocidade de reação aumenta com o aumento da velocidade superficial no reator RAHLF. Este comportamento pode ser atribuído à diminuição contínua da resistência à transferência de massa da fase líquida. O reator UASB apresentou baixa eficiência devido à flotação de 85% da manta de lodo granular, após 18 dias de operação. Os resultados obtidos neste trabalho permitem concluir que o reator RAHLF pode ser utilizado como unidade única no tratamento de efluentes com alta concentração de lipídios, devido a ter apresentado performance similar à observada no sistema integrado enzimático-anaeróbio. / The aim of this work was the investigation of the lipid degradation in three anaerobic treatment systems: a horizontal-flow anaerobic immobilized biomass (HAIB) reactor, a combined system composed by an inverted expanded-bed enzymatic reactor (EIBE) followed by a HAIB reactor and an up-flow anaerobic sludge blanket (UASB) reactor. The systems were monitored in a chamber under controlled temperature of 30 ± 0.5°C and fed with lipid-based synthetic wastewater, with chemical oxygen demand (COD) of 8748 ± 711 mg/L and 1820 ± 512 mg/L of oil and grease concentration. The HAIB reactor was operated with hydraulic detention time (HDI) of 24 hours for 100 days and it presented average COD and lipids removal efficiencies of 98.9 ± 0.4% and 94.9 ± 3.2%, respectively. The combined system (enzymatic/anaerobic reactors) presented COD and lipids removal efficiencies of 99.0 ± 0.3% and 94.2 ± 2.8%, respectively, operating with a HDI of 30 min in the enzymatic reactor and 24 h in the microbiological one. Afterwards, the HAIB reactor was subjected to decreasing HDI values from 24 to 8 h. Average COD and the lipids removal efficiencies of 87.04 ± 3.2% and 90.5 ± 2.7%, respectively, were achieved for the lower HDI applied (8 h). A kinetic model, based on first-order series and parallel reactions, indicated that the lipids reaction rate increased as the liquid superficial velocity was increased in the HAIB reactor, since the liquid-phase mass transfer resistance decreased continuously. The UASB reactor presented a poor performance, presenting flotation of the 85% of the granular sludge bed after 18 days of operation. The results obtained in this work permit the potential indication of HAIB reactor as the sole unit to treat lipid-rich wastewater, since the performance of the HAIB reactor was similar to that observed for the integrated hydrolytic-anaerobic system.

Le traitement des rejets textiles se fait habituellement via une filière physico-chimique couplée à un traitement biologique. La qualité de l’effluent obtenu obéit difficilement aux normes de recyclage ou de rejet dans le milieu naturel. Dans cet objectif, différentes combinaisons sont proposées: la coagulation floculation (CF) et/ou l’adsorption sur charbon actif (CAP) en poudre couplée aux techniques membranaires (microfiltration (MF) ou ultrafiltration (UF)), la photocatalyse couplée à un traitement aérobie biologique (système membranaire (BRM) ou réacteur discontinu séquentiel (RDS)) ou au traitement anaérobie par voie biologique ou chimique. Une comparaison générale a été réalisée pour optimiser le traitement adéquat. La combinaison CF-CAP-UF est un traitement efficace pour la réduction de la DCO, de la couleur et de la turbidité. La dégradation de deux colorants textiles (azoïque et phthalocyanine) a été étudiée par photocatalyse simple ou combinée à un BRM. Le traitement photocatalytique a été réalisé en présence de dioxyde de titane fixé sur un support en fibres de cellulose dans un réacteur à film tombant en présence d’irradiation UV. Pour les deux types de réacteurs biologiques, bien que la biomasse ait été influencée par la variation de la concentration en colorant et par le mode de fonctionnement continu pour le BRM, elle a pu résister. Après le pré-traitement nous avons obtenu une complète décoloration mais les sous produits photocatalytiques demeurent toxiques et peuvent empêcher l’abattement de la DCO. Dans une dernière partie, nous avons testé le couplage de la photocatalyse à un traitement chimique par hydrogénation catalytique ou biologique par boues granulaires. Cette dernière possibilité s’avère être efficace puisque des taux de décoloration supérieurs à 90% ont été atteints pour différents types de colorants et qu’aucune toxicité des produits obtenus lors du pré-traitement photocatalytique n’a été détectée / The treatment of textile wastewater is usually done by a set of physicochemical processes coupled with a biological treatment. The effluent quality abides with difficulty the norms for reuse or discharge in environment. Various treatment combinations have been tested such as coagulation-flocculation (CF) and adsorption on activated carbon (PAC) coupled with membrane technologies (microfiltration (MF) or ultrafiltration (UF)), photocatalysis coupled with a biological treatment (membrane bioreactor (MBR) or a sequential batch reactor (SBR) or a biological and chemical anaerobic treatment. A general comparison was made to optimise the appropriate treatment. The combination CF-PAC-UF is the most effective of non-biological systems in terms of COD, absorbance and turbidity removal. The degradation of an azoïc and a phthalocyanine textile dyes by simple photocatalysis or combined to a membrane bioreactor has been investigated. Photocatalysis was achieved in a falling film reactor containing titanium dioxide fixed on cellulose fibres under UV irradiation. For both biological systems, although biomass was influenced by the variation of dyes concentration and the continuous operating mode for the MBR, it could resist to the applied conditions. However, even after pre-treatment where full decolouration was achieved, photocatalytic by-products were toxic and could inhibit COD removal. Chemical and biological anaerobic treatment have been applied to textile dyes and combined with a photocatalytic process. Photocatalysis was able to remove more than 90% color from crude as well as autoxidized reduced dye solutions. The photocatalytic end-products were not toxic toward methanogenic bacteria

Under de senaste 30 åren så har antalet massa- och pappersbruk minskat medan den totala produktionen av massa och papper har ökat. En högre produktion per bruk tillsammans med en hårdare miljölagstiftning, sätter ett högre tryck på vattenreningen på varje bruk. I flera massa- och pappersbruk så är vattenreningen en av faktorerna som begränsar produktionen av massa och papper. Dessutom så renas oftast restvattnet från massa- och pappersbruken med aerob rening som kräver mycket elektricitet och som producerar slam. För att minska kostnaden av vattenreningen och för att öka kapaciteten, så kan en anaerob vattenrening användas före den aeroba reningen. Fördelar med att ha en anaerob rening före den aeroba reningen är att den minskar belastningen av organiskt material på den aeroba reningen, värdefull biogas produceras, anaerob rening producerar mindre slam och kräver mindre elektricitet. Däremot så innehåller restvattnet från massa- och pappersbruk en hög halt av sulfat, vilket har orsakat en instabil biogasproduktion på flera existerande anläggningar. En potentiell lösning på detta är att använda en ytterligare anaerob reaktor före den biogasproducerande reaktorn, med syftet att reducera sulfat. Syftet med detta projekt var att optimera en anaerob två-stegs process för att få en effektiv biogasproduktion och för en stabil process. I projektet har två upp-flöde anaerob packad bädd (UAPB) reaktorer använts. Den första reaktorn var anrikad med sulfatreducerande bakterier före starten av projektet och den andra reaktorn innehöll metanogener. Processvatten från ett massa- och pappersbruk som använder barrträd som råmaterial och gör termomekanisk massa, användes i projektet. Den anaeroba två-stegs processen optimerades genom att minska retentionstiden i båda reaktorerna; genom att undersöka alternativ för att minska sulfidkoncentrationen i inflödet till biogasreaktorn; och genom att minska tillsatsen av näringsämnen till processvattnet. Stabiliteten av två-stegsprocessen mättes genom att analysera sulfat, sulfid och COD innehållet med spektrofotometri; genom att analysera pH; genom att analysera innehållet av metan i biogasen med gaskromatografi; och genom att analysera flyktiga fettsyror i utflödet med högtrycksvätskekromatografi. Resultaten visade att processen var stabil när retentionstiden för den sulfatreducerande reaktorn och biogasreaktorn var 0.3 dagar respektive 1.5 dagar. Effektiviteten av borttagningen av sulfat och COD i den sulfatreducerande reaktorn var 82% respektive 31%. Innehållet av metan i biogasen i den sulfatreducerande reaktorn var 53% i genomsnitt. I biogasreaktorn var borttagningen av COD 32% och metanhalten i biogasen var 31% i genomsnitt. Den totala borttagningen av COD för tvåstegsprocessen var 61%, när reaktorerna var kopplade via en uppsamlingsflaska. Biometanpotentialen i processvattnet och i utflödet från den sulfatreducerande reaktorn var 147 NmL CH4/g VS respektive 47 NmL CH4/g VS. Slutsatsen av projektet är att processen var stabil när retentionstiden för den sulfatreducerande reaktorn och biogasreaktorn var 0.3 dagar respektive 1.5 dagar, motiverat med stabiliteten av borttagning av sulfat och COD. Däremot var metanpotentialen för utflödet från den sulfatreducerande reaktorn bara 32% jämfört med processvattnet och nedbrytbarheten av COD var lägre i utflödet än i processvattnet. Eftersom den sulfatreducerande reaktorn var stabil vid de testade förhållandena så skulle det vara intressant att testa en enstegsprocess i en UAPB reaktorpilot i framtiden. Det skulle även vara intressant att minska retentionstiden i biogasreaktorn för att se om metanhalten i biogasen ökar. / In the past 30 years, the number of P&amp;P mills have decreased while the total production of pulp and paper have increased. A higher production per mill together with a stringent environmental legislation puts a high pressure on the wastewater treatment of P&amp;P mills. In several P&amp;P mills the wastewater treatment is one of the factors limiting the production of pulp and paper. In addition, the wastewater is usually treated with aerobic treatment that consumes a high amount of electricity and produces sludge. To decrease the cost of the wastewater treatment and to increase the treatment efficiency, an anaerobic treatment can be used before the aerobic treatment. Advantages of having an anaerobic treatment before the aerobic treatment is that it reduces the organic loading of the aerobic treatment, valuable biogas is produced, anaerobic treatment produce less sludge and requires less electricity. However, the wastewater of P&amp;P mills is rich in sulphate, which have resulted in an unstable biogas production. A potential solution for this to have another anaerobic reactor before the biogas producing reactor, with the purpose to remove sulphate. The aim of this project was to optimize a two-step anaerobic treatment for an effective biogas production and for a stable process. In the project, two UAPB reactors were used. The first bioreactor (hereafter pretreatment reactor) was enriched with sulphate reducing bacteria before the start of the project while the second reactor contained methanogens (hereafter biogas reactor). Wastewater from a P&amp;P mill using the TMP process and soft wood as raw material was used in this project. The anaerobic two-step process was optimized by decreasing the HRT of both reactors, by investing alternatives to decrease the sulphide in the influent to the biogas reactor and by decreasing the addition of nutrients to the process water. The stability of the two-step process was measured by analysing the sulphate, sulphide and COD content spectrophotometrically; by analysing pH; by analysing the methane content in the headspace of the reactors with GC and by analysing the VFA content in the effluents using HPLC. The results showed that the process was stable when the HRT of the pretreatment reactor and biogas reactor was 0.3 days and 1.5 days, respectively. The removal efficiency of sulphate and COD in the pretreatment reactor was 82% and 31%, respectively. The methane content in the biogas of the PT reactor was 53% in average. The COD removal efficiency of the biogas reactor was 32% and there was in average 31% methane in the biogas. The average total COD removal efficiency of the two-step process was 61% when the reactors were coupled via a collection tank. The biomethane potential of the process water and the effluent of the pretreatment reactor was 147 NmL CH4/g VS and 47 NmL CH4/g VS, respectively. The process was stable when the HRT of the pretreatment reactor and biogas reactor was 0.3 days and 1.5 days, respectively, considering the stability of the sulphate and COD removal efficiency. However, the BMP of the effluent of the PT reactor was only 32% of the BMP of the process water and the degradability of the COD was lower in the effluent. Since the PT reactor exhibited stability at the tested conditions, it would be interesting to try it as a one-step process in a pilot UAPB reactor in the future. In the future, research is needed to investigate if the methane content in the headspace of the biogas reactor can be increased by decreasing the HRT of the reactor.

Avaliou-se o emprego de sistema biológico de tratamento em reator anaeróbio de leito estruturado em fluxo ascendente (RAnLE) para remoção do corante Direct Black 22 (DB22) e íons sulfato (65 e 200 mg.L-1, respectivamente), principais constituintes de efluente têxtil de indústrias de jeans da região de Caruaru, PE. Etanol foi utilizado como doador de elétrons na concentração de 1000 mg.DQO.L-1. As médias de remoção de DQO, sulfato e corante foram respectivamente 80,28 &#177; 6,62%, 78,66 &#177; 4,04% e 68 &#177; 5%. Cerca de 3% do sulfeto produzido foi identificado em solução, 10% esteve presente na forma gasosa e aproximadamente 87% precipitou em forma de cristais metálicos inorgânicos ou em enxofre elementar por exposição ao ar atmosférico ou por ação redutora do corante DB22, contribuindo para remoção de cor na transformação do corante em aminas aromáticas. Os ácidos graxos presentes no efluente tratado totalizaram 121 &#177; 34 mg.L-1, com predominância de ácido acético (95 &#177; 17 mg.L-1), sem prejuízo da capacidade tamponante do sistema, que apresentou aumento na alcalinidade pela ocorrência da sulfetogênese e pela característica básica das aminas aromáticas, produzidas por meio da quebra da ligação azo do corante, revelando absorção em diferentes comprimentos de onda na região do ultravioleta, denotando a produção de diferentes estruturas aromáticas. O efluente têxtil simulado foi mais tóxico do que seu correspondente tratado para ambas as situações (crônico e agudo) nos testes de toxicidade com Ceriodaphnia dúbia (crônica) e Daphnia magna (aguda), atestando o potencial dos reatores anaeróbios na destoxificação do corante azo Direct Black 22 para as espécies abordadas. Os testes de citotoxicidade in vitro empregando células McCoy (linhagem contínua de fibroblastos) em exposição ao efluente têxtil sintético tratado no RAnLE apresentaram um comportamento dose-dependente. O efluente diluído 3 vezes inibiu 50% das células. Por outro lado, não foi possível verificar um comportamento dose-dependente considerando as diferentes concentrações de DB22. Entretanto, houve diferença estatística significativa na viabilidade celular para as concentrações de DB22 de 0,016, 0,065, 0,2 e 0,26 mg.mL-1. Os resultados demonstram a necessidade do uso de diferentes testes de toxicidade a vários organismos, de forma a complementar os resultados obtidos pelos testes convencionais. Eletromicrografias da biomassa revelaram a presença de arqueias metanogênicas, demonstrando a capacidade de coexistência de comunidades sulfetogênicas e metanogênicas, dado o valor observado de DQO/sulfato de 5. O sequenciamento metagenômico em apontou grande abundância relativa de bactérias redutoras de sulfato (BRS), superior a 50%. Os bioensaios em batelada com o lodo de fundo e o lodo em suspensão do RAnLE apontaram que a biomassa aderida foi mais apta a suportar a carga tóxica proveniente do corante e das aminas aromáticas. A estrutura do RAnLE permitiu o estabelecimento de biomassa aderida e biomassa suspensa, concorrendo ambas para melhor desempenho do sistema. / The present work assessed the employment of an anaerobic up-flow fixed-structured bed (AUFFSB) reactor, which aimed to remove the main constituents of a simulated textile effluent with azo dye Direct Black 22 (DB22) and sulphate ions (65 and 200 mg.L-1, respectively), main constituents in residual waters generated by denim industry in Caruaru, PE. Ethanol was employed as electron donor (1000 mg.COD.L-1). Medium removals for COD, sulphate and dye concentration were respectively 80.28 &#177; 6.62%, 78.66 &#177; 4.04% and 68 &#177; 5%. Circa 3% of produced sulphide was identified in the effluent, 10% in gaseous state and approximately 87% precipitated either as metallic inorganic crystals, as elemental sulphur due to exposition to atmosphere, or due to the azo bound reduction of DB22, which contributed to colour removal in the generation of aromatic amines from the azo dye. The volatile fatty acids totalized 121 &#177; 34 mg.L-1 while acetic acid was the predominant one (95 &#177; 17 mg.L-1). Nevertheless, such concentrations did not impair the buffering capacity of the system, which had increased alkalinity due to the occurrence of sulphidogenesis and of the alkaline characteristic of the aromatic amines, which were produced from azo bound cleavage, revealing absorption in different wavelengths in the UV zone, inferring that different aromatic structures were formed. As for the toxicity, the simulated textile effluent was more toxic before treatment than after treatment for both bioessays employing Ceriodaphnia dubia and Daphnia magna, (chronic and acute toxicity), attesting the potential of anaerobic reactors to detoxify azo dye DB22. The in vitro cytotoxicity tests using McCoy cells (fibroblasts of a continuous lineage) exposed to simulated textile effluent treated on the anaerobic bioreactor presented a dose-dependent behaviour. The effluent diluted 3 times showed inhibition to 50% of the cells. On the other hand, it was not possible to verify a dose-dependent behaviour considering the different concentrations of DB22. However, there was significant statistical difference on cell viability for DB22 concentrations of 0.016, 0.065, 0.2 and 0.26 mg.mL-1. The results pointed to the need of diverse toxicity tests to various organisms in order to complement the results obtained by conventional used ones. Micrographs revealed the presence of methanogenic archeas, denoting the possibility of coexistence between sulphidogenic and methanogenic communities, considering the observed COD/sulphate ration of 5. Metadata obtained from metagenomic sequencing revealed high relative abundance of sulphate-reducing bacteria (SRB), which was superior to 50%. Batch bioessays showed that biomass in supporting material is more capable of enduring the toxic load from DB22 and aromatic amines. The AUFFSB structure enabled that suspended biomass developed along with fixed biomass, thus both collaborated for a better system performance.

Avaliou-se o emprego de sistema biológico de tratamento em reator anaeróbio de leito estruturado em fluxo ascendente (RAnLE) para remoção do corante Direct Black 22 (DB22) e íons sulfato (65 e 200 mg.L-1, respectivamente), principais constituintes de efluente têxtil de indústrias de jeans da região de Caruaru, PE. Etanol foi utilizado como doador de elétrons na concentração de 1000 mg.DQO.L-1. As médias de remoção de DQO, sulfato e corante foram respectivamente 80,28 &#177; 6,62%, 78,66 &#177; 4,04% e 68 &#177; 5%. Cerca de 3% do sulfeto produzido foi identificado em solução, 10% esteve presente na forma gasosa e aproximadamente 87% precipitou em forma de cristais metálicos inorgânicos ou em enxofre elementar por exposição ao ar atmosférico ou por ação redutora do corante DB22, contribuindo para remoção de cor na transformação do corante em aminas aromáticas. Os ácidos graxos presentes no efluente tratado totalizaram 121 &#177; 34 mg.L-1, com predominância de ácido acético (95 &#177; 17 mg.L-1), sem prejuízo da capacidade tamponante do sistema, que apresentou aumento na alcalinidade pela ocorrência da sulfetogênese e pela característica básica das aminas aromáticas, produzidas por meio da quebra da ligação azo do corante, revelando absorção em diferentes comprimentos de onda na região do ultravioleta, denotando a produção de diferentes estruturas aromáticas. O efluente têxtil simulado foi mais tóxico do que seu correspondente tratado para ambas as situações (crônico e agudo) nos testes de toxicidade com Ceriodaphnia dúbia (crônica) e Daphnia magna (aguda), atestando o potencial dos reatores anaeróbios na destoxificação do corante azo Direct Black 22 para as espécies abordadas. Os testes de citotoxicidade in vitro empregando células McCoy (linhagem contínua de fibroblastos) em exposição ao efluente têxtil sintético tratado no RAnLE apresentaram um comportamento dose-dependente. O efluente diluído 3 vezes inibiu 50% das células. Por outro lado, não foi possível verificar um comportamento dose-dependente considerando as diferentes concentrações de DB22. Entretanto, houve diferença estatística significativa na viabilidade celular para as concentrações de DB22 de 0,016, 0,065, 0,2 e 0,26 mg.mL-1. Os resultados demonstram a necessidade do uso de diferentes testes de toxicidade a vários organismos, de forma a complementar os resultados obtidos pelos testes convencionais. Eletromicrografias da biomassa revelaram a presença de arqueias metanogênicas, demonstrando a capacidade de coexistência de comunidades sulfetogênicas e metanogênicas, dado o valor observado de DQO/sulfato de 5. O sequenciamento metagenômico em apontou grande abundância relativa de bactérias redutoras de sulfato (BRS), superior a 50%. Os bioensaios em batelada com o lodo de fundo e o lodo em suspensão do RAnLE apontaram que a biomassa aderida foi mais apta a suportar a carga tóxica proveniente do corante e das aminas aromáticas. A estrutura do RAnLE permitiu o estabelecimento de biomassa aderida e biomassa suspensa, concorrendo ambas para melhor desempenho do sistema. / The present work assessed the employment of an anaerobic up-flow fixed-structured bed (AUFFSB) reactor, which aimed to remove the main constituents of a simulated textile effluent with azo dye Direct Black 22 (DB22) and sulphate ions (65 and 200 mg.L-1, respectively), main constituents in residual waters generated by denim industry in Caruaru, PE. Ethanol was employed as electron donor (1000 mg.COD.L-1). Medium removals for COD, sulphate and dye concentration were respectively 80.28 &#177; 6.62%, 78.66 &#177; 4.04% and 68 &#177; 5%. Circa 3% of produced sulphide was identified in the effluent, 10% in gaseous state and approximately 87% precipitated either as metallic inorganic crystals, as elemental sulphur due to exposition to atmosphere, or due to the azo bound reduction of DB22, which contributed to colour removal in the generation of aromatic amines from the azo dye. The volatile fatty acids totalized 121 &#177; 34 mg.L-1 while acetic acid was the predominant one (95 &#177; 17 mg.L-1). Nevertheless, such concentrations did not impair the buffering capacity of the system, which had increased alkalinity due to the occurrence of sulphidogenesis and of the alkaline characteristic of the aromatic amines, which were produced from azo bound cleavage, revealing absorption in different wavelengths in the UV zone, inferring that different aromatic structures were formed. As for the toxicity, the simulated textile effluent was more toxic before treatment than after treatment for both bioessays employing Ceriodaphnia dubia and Daphnia magna, (chronic and acute toxicity), attesting the potential of anaerobic reactors to detoxify azo dye DB22. The in vitro cytotoxicity tests using McCoy cells (fibroblasts of a continuous lineage) exposed to simulated textile effluent treated on the anaerobic bioreactor presented a dose-dependent behaviour. The effluent diluted 3 times showed inhibition to 50% of the cells. On the other hand, it was not possible to verify a dose-dependent behaviour considering the different concentrations of DB22. However, there was significant statistical difference on cell viability for DB22 concentrations of 0.016, 0.065, 0.2 and 0.26 mg.mL-1. The results pointed to the need of diverse toxicity tests to various organisms in order to complement the results obtained by conventional used ones. Micrographs revealed the presence of methanogenic archeas, denoting the possibility of coexistence between sulphidogenic and methanogenic communities, considering the observed COD/sulphate ration of 5. Metadata obtained from metagenomic sequencing revealed high relative abundance of sulphate-reducing bacteria (SRB), which was superior to 50%. Batch bioessays showed that biomass in supporting material is more capable of enduring the toxic load from DB22 and aromatic amines. The AUFFSB structure enabled that suspended biomass developed along with fixed biomass, thus both collaborated for a better system performance.