ABSTRACT The hydrogen is a fuel with a high energy density. Studies have sought to verify the potential of different residues and configurations of reactors in the production of biohydrogen. This study evaluated the influence of the organic loading rate on the production of biohydrogen from cassava starch wastewater (CSW) in anaerobic sequencing batch biofilm reactors (AnSBBR) operated in a fed-batch. In the tests, the organic loading rates of 9.0; 13.5 and 18.0 gCT L−1 d−1 were used, at cycle times (CT) of 4; 4 and 2 h (tests I, II and III, respectively). The reactor was inoculated with sludge from a pilot anaerobic reactor used in the treatment of CSW, heat treated (heated at 90°C for 15 min). With the increase of the organic load (condition I to II) with the same cycle time (CT: 4 h), there were increases in the hydrogen molar productivity (PrM) and hydrogen yield in relation to applied total carbohydrate (RMCA) and removed (RMCR). However, with the increase in the organic loading rate in which the CT was reduced from 4 to 2 h (condition II to III), there was a decrease in PrM and RMCA and RMCR. The best performance of the reactor was verified in condition II (organic loading rate: 13.5 gTC L− 1 d−1; CT: 4 h), in which the PrM was 35.8 molH2 m−3 d−1 and RMCA and RMCR were 2.24 and 3.67 molH2 kgTC−1, respectively.

ABSTRACT The hydrodynamic behavior of an anaerobic fixed bed reactor (AFBR) was evaluated in the treatment of cattle slaughterhouse wastewater. The AFBR was operated at hydraulic retention time (HRT) of 14, 11 and 8 h. Stimulus-response assays were carried out with Eosin Y and the experimental data were adjusted to the single-parameter theoretical models of dispersion and N-continuous stirred tank reactors in series (N-CSTR). The experimental results of the residence time distribution curves showed that at lower flow rate, the reactor showed plug flow behavior with correlation coefficient (r) of 0.88 and number of dispersion of 0.2 for high dispersion (HD). However, at higher and intermediate flow rates, the AFBR behave as a complete mixture flow, (r) of 0.94 and 0.96, respectively. Residence time distribution curves in the AFBR showed a good approximation of the complete mixing model at hydraulic residence time of 11 and 8 h, with 5 and 2 N-CSTR reactors in series, respectively. The volume of dead zones corresponding to 43.0, 37.4 and 11.2% of the volume of the reactor for HRT of 14, 11 and 8 h, respectively, was noted, and hydraulic short circuiting were not confirmed.

ABSTRACT The aim of this study was to evaluate the behavior of an anaerobic reactor of packed-bed and continuous flow, in relation to the biogas and methane production and the removal of organic load, from the wastewater of cassava starch extraction. For this purpose, were tested, in a reactor with a useful volume of 2.82 L and support mean of polypropylene filled with polyethylene foam, the organic loading rate (OLR) of 2.5, 5.0, 8.0 and 10.0 g L-1d-1. It was evaluated the removal of COD, the pH, the VA/TA ratio, the biogas and the methane production. It was concluded from this study that it is possible to produce biogas with methane percentages higher than 80% (maximum) and remove the organic load more than 90% under the tested conditions. In relation to stability, the reactor can be considered stable for the parameters, pH, the relationship between volatile acidity and total alkalinity and organic load removal. The best results in relation to the average volumetric biogas production (0.174 and 0.311 L g COD-1) were obtained for the higher organic loading rate (of 8 and 10 g L-1d-1, respectively) and the observed tendency is that with the increase of the organic loading rate, the specific biogas production will increase as well as the specific production of methane.

ABSTRACT The anaerobic digestion (AD) operation complexity raise the importance of stability testing to verify whether the operating conditions are under control and whether the process is working as required. The current method of verifying process stability is by a range of the ratio between volatile fatty acidity and total alkalinity (VFA/ TA) within which stable conditions are brought about; these rates vary with the content of organic material. A few indicators as pH or constant biogas production are also used. Therefore, the aim of this study was to propose the use of Shewhart control chart for individual measures as a stability test for AD, as well as to demonstrate its use in poultry litter AD. The method showed to be advantageous since it standardizes a variation range for the process according to the average and verifies the stability by direct measures, such as organic material removal efficiency and biogas production.

ABSTRACT The aim of this study was to monitor the stabilization of a sequential batch reactor (SBR) regarding the partial nitritation of poultry slaughterhouse wastewater, aiming at preparing it for a reactor with bacteria that promote anaerobic ammonia oxidation (anammox). A cylindrical reactor with a useful volume of 3.5 L, mechanical agitation (50 rpm), and suspended biomass was used in the experiment. The strategies adopted for nitrite-oxidizing bacteria (NOB) inhibition were cycle time (CT: 24, 16, 6, 5, 4 h and real-time monitoring), free ammonia accumulation, alkalinity restriction and low concentrations of dissolved oxygen (DO). The ammonification process, observed at all experimental phases, negatively influenced the control of partial nitritation process. Alkalinity restriction under low cycle times (4 and 5 h) conditions, together with low dissolved oxygen concentration, was a key factor for nitrite-oxidizing bacteria inhibition. Stability of partial nitritation was only reached by real-time monitoring, being the cycles stopped when 50% N–NH4+ and 50% N–NO2− were present in the reactor.

ABSTRACT Fixed-bed reactors have been considered promise alternatives for hydrogen production due to their simple construction and increase in the biomass retention. The purpose of this study was to investigate the biological production of hydrogen in anaerobic fixed-bed reactors with cassava starch wastewater used as substrate. Different support materials and arrangements of fixed-bed were used to evaluate the biological production of hydrogen in anaerobic continuous fixed-bed reactors, with cassava starch wastewater as substrate - recycled low-density polyethylene scraps, in packed bed (R1), recycled low-density polyethylene cylinders, in ordained bed (R3) and bamboo stems, in vertical arrangement (R2 and R4). In R1 the initial pH was adjusted for 6.0, with hydraulic retention time (HRT) of 4 h and organic loading rate (OLR) of 9.5 g.L−1.d−1. In R2 the initial pH was maintained in 4.5, with HRT of 4 h and OLR of 9.5 g.L−1.d−1. R3 and R4 were operated with initial pH of 4.5, HRT of 4 h and OLR of 13.5 g.L−1.d−1. The volumetric hydrogen production (VHPR) was favored by lower OLR applied, evenin different pH ranges (6.0 and 4.5). VHPR values of 229 mL H2.L−1.d−1and 248 mL H2.L−1.d−1 were obtained in R1 and R2, respectively. Both in the bamboo stems bed as in the polyethylene cylinders bed, the increase of OLR and the reduction of the initial pH resulted in a diminishing of VHPR to 175 mL H2.d−1.L−1 (R3) and 145 m LH2 .d−1.L−1 (R4). Higher concentrations of butanol (821.32 and 1,529.22 mg.L−1) and ethanol (915.41 and 924.41 mg.L−1) were verified in the reactors with bamboo stems. In R4, the increase of OLR and the reduction of the initial pH contributed to the increase of butanol concentration in 1.8 times, diminishing the VHPR in 41.68%, yield in 63.95% and H2 in 37.6%, and indicating that the effect of pH is more pronounced with the increase of OLR, leading to the solventogenesis.

RESUMO O 2-feniletanol (FE) é um álcool aromático com odor característico de rosas, amplamente utilizado na indústria alimentícia para modificar composições de aroma em formulações com frutas, geleias, pudins, gomas de mascar e também na indústria de cosméticos e perfumes. Este composto é encontrado naturalmente, em baixas concentrações, em óleos essenciais de algumas flores e plantas. Uma alternativa à extração de vegetais são os processos biotecnológicos. Neste trabalho, foi avaliada a produção de 2-feniletanol no cultivo de Saccharomyces cerevisiae em água residuária de indústria de fécula de mandioca. O substrato foi suplementado com glicose e L-fenilalanina, a fim de obter as condições de maior geração de 2- -feniletanol e maior eficiência de conversão glicose/2-feniletanol. Foi realizada otimização através de planejamento composto central rotacional e de análise de superfície de resposta. Os cultivos foram mantidos em condições aeróbias, em processo em batelada, em frascos Erlenmeyer com capacidade para 250 mL, contendo 50 mL de meio, em agitador regulado a 150 rpm e 24±1ºC. Os maiores valores de FE foram alcançados com a suplementação de 20,0 g.L-1de glicose e de 5,5 g.L-1 de L-fenilalanina, os quais foram validados experimentalmente, obtendo-se produção de FE de 1,33 g.L-1 e fator de rendimento FE/glicose de 0,070 g.g-1, que equivaleram a 74,3 e 89,7% dos valores de desejabilidade, segundo o modelo validado.

ABSTRACT 2-Phenylethanol (PE) is an aromatic alcohol with a characteristic odor of roses, widely used in food industry to modify certain aroma compositions in formulations with fruit, jam, pudding, and chewing gums, and also in cosmetic and fragrance industry. This compound occurs naturally in low concentrations in some essential oils from flowers and plants. An alternative to plants extraction are biotechnological processes. This study evaluated 2-phenylethanol’s production in cultivation of Saccharomyces cerevisiae in cassava wastewater originated from starch industry. The substrate was supplemented with glucose and L-phenylalanine in order to obtain higher 2-phenylethanol concentrations and better efficiency in glucose/2-phenylethanol conversion. It was performed using Rotatable Center Composite Design and response surface analysis. Cultures were performed under aerobic conditions in a batch system in Erlenmeyer flasks containing 50 mL of medium in shaker at 150 rpm and 24 ± 1 ºC. The highest PE values were obtained with supplementation of 20.0 g.L-1 of glucose and 5.5 g.L-1 of L-phenylalanine, which has been experimentally validated, obtaining a PE production of 1.33 g.L-1 and PE/glucose yield factor of 0.070 g.g-1, equivalent to 74.3 and 89.7% of desirability values according to the validated model.

Este trabalho teve por objetivo avaliar a influência da vazão de ar (0,25; 0,50 e 0,75 L.L-1.min-1) e do tempo de ciclo (10h45; 14h25 e 17h35) no desempenho de um reator em bateladas sequenciais (RBS) em promover a nitrificação e a desnitrificação de água residuária de abatedouro de aves. A operação contemplou as etapas de alimentação, reação aerada e anóxica, sedimentação e descarte. O RBS foi operado em escala de bancada com volume útil de 4 L, mantendo-se 25% do volume do reator como inóculo em cada batelada. Na fase anóxica, a relação C:N foi mantida entre 5 e 6, adicionando-se água residuária do processo de obtenção de fécula de mandioca. Elaborou-se um planejamento fatorial (22) com cinco repetições, no ponto central, para verificar a influência dos fatores, o tempo de ciclo e a vazão de ar, na variável resposta remoção de nitrogênio inorgânico total (N-NH4++N-NO2-+N-NO3-), no processo completo (nitrificação e desnitrificação). A maior remoção de nitrogênio inorgânico total (93,3%) foi observada quando se utilizou vazão de ar de 0,25 L.L-1.min-1 e tempo de ciclo de 14h25. No final do experimento, o lodo do reator foi caracterizado através de hibridização fluorescente in situ (FISH), indicando a presença de bactérias oxidadoras de amônia e de nitrito.

This study aimed to evaluate the influence of airflow (0.25, 0.50 and 0.75 L.L-1.min-1) and cycle time (10.45 h, 14.25 h and 17.35 h) on a sequencing batch reactor (SBR) performance in promoting nitrification and denitrification of poultry slaughterhouse wastewater. The operational stages included feeding, aerobic and anoxic reactions, sedimentation and discharge. SBR was operated in a laboratory scale with a working volume of 4 L, keeping 25% of biomass retained inside the reactor as inoculum for the next batch. In the anoxic stage, C: N ratio was maintained between 5 and 6 by adding cassava starch wastewater. A factorial design (22) with five repetitions was designed at the central point to evaluate the influence of cycle time and airflow on total inorganic nitrogen removal (N-NH4++N-NO2-+N-NO3-) and in the whole process (nitrification and denitrification). The highest total inorganic nitrogen removal (93.3%) was observed for airflow of 0.25 L.L-1.min‑1 and a cycle time of 14.25 h. At the end of the experiment, the sludge inside the reactor was characterized by fluorescent in situ hybridization (FISH), indicating the presence of ammonia and nitrite oxidizing bacteria.

Buscando aliar o tratamento de resíduos à produção de energia limpa e renovável, o presente trabalho teve como objetivo avaliar a produção biológica de hidrogênio a partir da água residuária da indústria de fécula de mandioca, gerada durante os processos de extração e de purificação do amido. O experimento foi conduzido em um reator anaeróbio de leito fixo, contínuo, de 3 L de volume útil, em que o meio suporte consistiu em hastes de bambu. O sistema foi operado a 36 º C, pH inicial 6,0 e sob variações de carregamento orgânico. A maior taxa de produção de hidrogênio de 1,1 L d-1 L-1 foi obtida com aplicação da taxa de carregamento orgânico de 35 g L-1d-1, em termos de açúcares totais, e tempo de detenção hidráulica de 3 h, com predomínio dos ácidos butírico e acético como produtos finais da fermentação. As baixas relações C/N contribuíram com o crescimento excessivo da biomassa, ocasionando redução de até 35% na produção de hidrogênio, baixos percentuais de H2 e elevadas concentrações de CO2 no biogás.

Attempting to associate waste treatment to the production of clean and renewable energy, this research sought to evaluate the biological production of hydrogen using wastewater from the cassava starch treatment industry, generated during the processes of extraction and purification of starch. This experiment was carried out in a continuous anaerobic reactor with a working volume of 3L, with bamboo stems as the support medium. The system was operated at a temperature of 36°C, an initial pH of 6.0 and under variations of organic load. The highest rate of hydrogen production, of 1.1 L.d-1.L-1, was obtained with application of an organic loading rate of 35 g.L-1.d-1, in terms of total sugar content and hydraulic retention time of 3h, with a prevalence of butyric and acetic acids as final products of the fermentation process. Low C/N ratios contributed to the excessive growth of the biomass, causing a reduction of up to 35% in hydrogen production, low percentages of H2 and high concentrations of CO2in the biogas.

As fecularias produzem grande volume de manipueira que, estabilizado em lagoas, provoca desperdício da energia do biogás e a poluição da atmosfera. Para contribuir com a reversão dessa realidade, desenvolveu-se esta pesquisa de tratamento de manipueira de fecularia em reator anaeróbio tubular horizontal piloto, com meio suporte, em peças de bambu. O reator foi escavado no solo e impermeabilizado com geomembrana, com volume de 33,6 m³ e alimentação contínua por gravidade. Os indicadores de estabilidade foram pH, relação acidez volátil/alcalinidade total e produção de biogás. O delineamento experimental foi o inteiramente casualizado, com respostas submetidas à análise multivariada. As cargas orgânicas em termos de demanda química de oxigênio (DQO) foram de 0,556; 0,670; 0,678 e 0,770 g L-1 e em sólidos voláteis (SV) de 0,659; 0,608; 0,570 e 0,761 g L-1 para os tempos de retenção hidráulica (TRH) de 13,0; 11,5; 10,0 e 7,0 dias, respectivamente. As reduções médias de DQO foram de 88; 80; 88 e 67% e de SV de 76; 77; 65 e 61%, respectivamente. As produções de biogás por DQO consumida foram de 0,368; 0,795; 0,891 e 0,907 L g-1, por SV consumidos de 0,524; 0,930; 1,757 e 0,952 L g-1 e volumétrica de 0,131; 0,330; 0,430 e 0,374 L L-1 d-1. O reator permaneceu estável, e as peças de bambu, em análise visual ao final do experimento, apresentaram-se fisicamente íntegras.

The cassava starch industries generate a large volume of wastewater effluent that, stabilized in ponds, wastes its biogas energy and pollutes the atmosphere. To contribute with the reversion of this reality, this manipueira treatment research was developed in one phase anaerobic horizontal pilot reactor with support medium in bamboo pieces. The reactor was excavated into the ground and sealed with geomembrane in HDPE, having a volume equal to 33.6 m³ and continuous feeding by gravity. The stability indicators were pH, volatile acidity/total alkalinity ratio and biogas production. The statistical analyses were performed by a completely randomized design, with answers submitted to multivariate analysis. The organical loads in COD were 0.556; 0.670; 0.678 and 0.770 g L-1 and in volatile solids (VS) of 0.659; 0.608; 0.570 and 0.761 g L-1 for the hydraulic retention times (HRT) of 13.0; 11.5; 10.0 and 7.0 days, respectively. The reductions in COD were 88; 80; 88 and 67% and for VS of 76; 77; 65 and 61%. The biogas productions relatively to the consumed COD were 0.368; 0.795; 0.891 and 0.907 Lg-1, for the consumed VS of 0.524; 0.930; 1.757 and 0.952 Lg-1 and volumetric of 0.131; 0.330; 0.430 and 0.374 L L-1 d-1. The reactor remained stable and the bamboo pieces, in visual examination at the end of the experiment, showed to be in good physical conditions.

O objetivo deste estudo foi avaliar o desempenho de um Reator Anaeróbio-Aeróbio de Leito Fixo (RAALF) com escoamento ascendente, no tratamento de efluente bruto de matadouro bovino, e obter constantes cinéticas aparentes da remoção de matéria orgânica. O RAALF foi operado sem recirculação (Etapa I) e com 50% de recirculação do efluente (Etapa II), com θ de 11 h e 8 h. Em termos de pH, alcalinidade a bicarbonato e ácidos voláteis, os resultados indicaram que o RAALF apresentou capacidade em manter condições favoráveis para os processos biológicos envolvidos na remoção de matéria orgânica, em ambas as etapas operacionais. As eficiências médias de remoção de matéria orgânica ao longo da altura do reator, expressa em termos de DQO bruta, foram de 49% e 68% na Etapa I e de 54% e 86% na Etapa II, para θ de 11 h e 8 h, respectivamente. Os resultados de DQO filtrada indicaram eficiências de remoção de 52% e k = 0,0857 h-1 para θ de 11 h e 42% e k = 0,0880 h-1 para θ de 8 h na Etapa I. Na Etapa II, as eficiências de remoção foram 59% e 51% para θ de 11 h e 8 h, com k = 0,1238 h-1 e k = 0,1075 h-1, respectivamente. O modelo cinético de primeira ordem indicou bom ajuste e descreveu adequadamente a cinética de remoção de matéria orgânica para θ de 11 h, com r² igual a 0,9734 e 0,9591 para as Etapas I e II, respectivamente.

This paper sought to evaluate the behavior of an upflow Anaerobic-Aerobic Fixed Bed Reactor (AAFBR) in the treatment of cattle slaughterhouse effluent and determine apparent kinetic constants of the organic matter removal. The AAFBR was operated with no recirculation (Phase I) and with 50% of effluent recirculation (Phase II), with θ of 11h and 8h. In terms of pH, bicarbonate alkalinity and volatile acids, the results indicated the reactor ability to maintain favorable conditions for the biological processes involved in the organic matter removal in both operational phases. The average removal efficiencies of organic matter along the reactor height, expressed in terms of raw COD, were 49% and 68% in Phase I and 54% and 86% in Phase II for θ of 11h and 8h, respectively. The results of the filtered COD indicated removal efficiency of 52% and k = 0.0857h-1 to θ of 11h and 42% and k = 0.0880h-1 to θ of 8h in the Phase I. In Phase II, the removal efficiencies were 59% and 51% to θ of 11h and 8h, with k = 0.1238h-1 and k = 0.1075 h-1, respectively. The first order kinetic model showed good adjustment and described adequately the kinetics of organic matter removal for θ of 11h, with r² equal to 0.9734 and 0.9591 to the Phases I and II, respectively.

O objetivo do trabalho foi avaliar a efici�ncia de um reator em batelada sequencial (RBS) na remo�ção biológica de nitrog�nio de efluente de abatedouro bovino, por meio dos processos de nitrifica�ção/desnitrifica�ção. Foram investigados os efeitos da concentra�ção inicial de nitrog�nio amoniacal de 100; 150 e 200 mg L-1 e vazção de ar de 0,125; 0,375 e 0,625 L min-1 Lreator-1 na remo�ção de compostos nitrogenados, por meio de configura�ção de um planejamento do tipo Delineamento Composto Central Rotacional (DCCR). Foram verificadas varia�›es de 9,2 a 94,9%, 4,0 a 19,6% e 20,8 a 92,0% na conversção de nitrog�nio amoniacal a nitrato, acœmulo de nitrito e remo�ção de nitrog�nio total, respectivamente. O aumento da vazção de ar e a diminui�ção da concentra�ção inicial de nitrog�nio amoniacal resultaram em maiores efici�ncias na remo�ção de nitrog�nio total e na conversção de nitrog�nio amoniacal a nitrato. Nos intervalos preestabelecidos do estudo, efici�ncias de remo�ção e conversção dos compostos nitrogenados, superiores a 85%, foram atingidas com varia�ção de vazção de ar de 0,375 a 0,725 L min-1 Lreator-1 e concentra�ção inicial de nitrog�nio amoniacal de 80 a 200 mg L-1. No processo de desnitrifica�ção, foram obtidas efici�ncias de 91,5 a 96,9% na remo�ção de nitrito/nitrato e de 78,3 a 87,9% na remo�ção de matŽria org‰nica.

The aim of this study was to evaluate the efficiency of a sequencing batch reactor (SBR) on biological removal of nitrogen from cattle slaughterhouse wastewater by nitrification/denitrification processes. The effects of initial concentration of ammoniacal nitrogen were investigated at 100; 150 and 200 mg L-1 and air flow rate at 0.125; 0.375 and 0.625 L min¹ Lreactor-1 on the nitrogen compounds removal, by a Central Composite Rotational Design (CCRD) configuration. There were variations from 9.2 to 94.9%, 4.0 to 19.6% and 20.8 to 92.0% in the conversion of ammoniacal nitrogen to nitrate and nitrite concentration and removal of total nitrogen, respectively. The increase of air flow rate and decrease of the initial concentration of ammoniacal nitrogen resulted in higher efficiencies of total nitrogen removal, as well as the conversion of ammoniacal nitrogen to nitrate. During the pre-established intervals of this study, the removal and conversion efficiencies of nitrogen compounds above 85% were achieved in air flow rate variations from 0.375 to 0.725 L min-1 Lreactor-1 and initial concentration of ammoniacal nitrogen from 80 to 200 mg L-1. On denitrification process, we obtained efficiencies from 91.5 to 96.9% on the removal of nitrite/nitrate and from 78.3 to 87.9% on the removal of organic matter.

A folha de mandioca, resíduo gerado na colheita das raízes, caracteriza-se pelo alto teor de proteínas, vitaminas e minerais, no entanto sua utilização é reduzida devido ao alto teor de fibras e substâncias antinutricionais que podem ser removidas durante obtenção de concentrados proteicos. Neste contexto, o objetivo do presente trabalho foi avaliar processos de extração de proteínas, visando ao aproveitamento das folhas de mandioca (Manihot esculenta Crantz) como alternativa proteica. Quatro métodos foram testados: 1) Coagulação de Proteínas por Abaixamento da Temperatura; 2) Extração por Precipitação Isoelétrica; 3) Solubilização das Proteínas; 4) Fermentação do Suco de Folhas Filtrado. Para a obtenção dos concentrados, avaliaram-se também a utilização de folhas frescas ou secas e a extração em uma ou duas etapas. A solubilização das proteínas (método 3) apresentou maior rendimento de extração, no entanto com concentrado de baixa qualidade. A fermentação do suco (método 4) produziu concentrados com mais qualidade e menores custos, e a precipitação isoelétrica (método 2) promoveu a obtenção de concentrados em menor tempo, sendo ambos com boas perspectivas de utilização. A utilização de duas etapas de extração não foi vantajosa ao processo e não houve diferença entre a utilização de folha seca ou fresca, sendo que a utilização de folhas frescas se apresenta como boa opção pela simplicidade do método.

The cassava leaf, waste generated in the harvest of the roots, is characterized by high content of protein, vitamins and minerals; however, its use is limited due to the high fiber content and antinutritional substances, which can be removed by obtaining protein concentrates. In this context, the objective of this study was to evaluate protein extraction processes, aiming the use of cassava leaves (Manihot esculenta Crantz) as an alternative protein. Four methods were tested: 1) Coagulation of Proteins by Lowering the Temperature, 2) Extraction by Isoelectric Precipitation, 3) Solubilization of Proteins and 4) Fermentation of Filter Leaf Juice. To obtain the concentrates, the use of fresh or dried leaves and extraction in one or two steps were also evaluated. The solubilization of proteins (method 3) showed a higher extraction yield; however, with concentrate of low quality. The fermentation of the juice (method 4) produced concentrates with higher quality and lower costs and the isoelectric precipitation (method 2) promoted the obtention of concentrates in less time, both with good prospects for use. The use of two extraction steps was not advantageous to the process and there was no difference between the use of fresh or dried leaf, and the use of fresh leaves is presented as a good option for the simplicity of the method.

A utilização de reatores anaeróbios com meio suporte no tratamento de efluentes líquidos, provenientes das fecularias de mandioca, tem-se apresentado como uma opção viável, uma vez que possibilita a aplicação de cargas orgânicas elevadas e uma redução considerável do TDH necessário para o tratamento. O objetivo do trabalho consistiu no estudo do processo de biodigestão, em dois reatores anaeróbios, com meio suporte de bambu, no tratamento de efluente de fecularia de mandioca, por meio da avaliação do desempenho dos mesmos. Foram utilizados dois reatores com relações diâmetro:comprimento 1:6 e 1:3. As cargas orgânicas aplicadas aos sistemas foram 0,519; 1,156; 1,471; 3,049; 4,347; 4,708 e 5,601 g.L-1d-1. Com relação à eficiência de remoção de DQO, ST e STV, não foram obtidas diferenças estatísticas entre os reatores. Os dois sistemas avaliados apresentaram comportamento estável em relação à AV/AT (acidez volátil/alcalinidade total) para todas as cargas submetidas. Os reatores apresentaram tendência à manutenção da produção de biogás em função da DQO consumida, para as três últimas cargas orgânicas aplicadas, indicando uma capacidade de suportar cargas orgânicas mais elevadas.

The use of anaerobic reactors with media support in the treatment of wastewater from the cassava starch industry has emerged as a viable option because it allows the application of high organic loads and a significant reduction of the HDT needed for the treatment. This research aimed at studying the process of biodigestion in two anaerobic reactors with bamboo support, in the treatment of effluent of cassava starch, by evaluating their performance. The two reactors used present the following diameter: length ratio, 1:6 and 1:3. The organic loads applied to the systems were 0.519, 1.156, 1.471, 3.049, 4.347, 4.708 and 5.601g.L-1.d-1. Regarding the efficiency of removal of COD, TS and TVS, no statistically significant differences were obtained between the reactors. The two systems evaluated showed a stable behavior with respect to the VA/TA (volatile acidity/total alkalinity) for all submitted loads. The reactors tended to the maintenance of biogas production as a function of consumed COD for the last three organic loads applied, indicating an ability to withstand higher organic loads.

O Programa Nacional de Produção e Uso do Biodiesel introduziu o biodiesel na matriz energética brasileira, trazendo a perspectiva de aumento da oferta de glicerina, coproduto gerado na proporção de 10 kg para cada 100 L de biodiesel. O objetivo principal deste trabalho foi avaliar a adição de glicerina bruta na digestão anaeróbia de efluente de indústria de fécula de mandioca (manipueira), em reator de fluxo semicontínuo horizontal de uma fase, em escala de laboratório. Foi utilizado um reator com volume útil de 8,77 L, meio suporte em eletroduto corrugado de policloreto de vinila (PVC), temperatura de 261 ºC, alimentado com manipueira e glicerina, aplicando-se tempos de detenção hidráulica de 4 e 5, dias e cargas orgânicas volumétricas crescentes de 3,05; 9,32; 14,83 e 13,59 g COD L-1 d-1, obtidas com a adição de glicerina aos níveis de 0; 2; 3 e 2% (v/v), respectivamente. As eficiências de remoção média de ST e STV foram decrescendo a partir da adição de glicerina à manipueira, com médias de 81,19 a 55,58 % para ST e 90,21 a 61,45% para STV. A adição de glicerina em 2% aumentou a produção de biogás em relação ao tratamento-controle, chegando a 1,979 L L-1 d-1. A produção de biogás em função da DQO consumida foi maior para o tratamento-controle que, para os tratamentos com adição de glicerina, indica menor conversão da matéria orgânica em biogás.

The Brazil's Biodiesel Production and Use Program introduces biodiesel in the Brazilian energy matrix, bringing along the perspective of a growth of the glycerin offer, co-product generated in the proportion of 10 kg for each 100 L of biodiesel. The aim of this study was to evaluate the addition of crude glycerin in the anaerobic digestion of cassava starch industry effluent (cassava wastewater), in a horizontal semi-continuous flow reactor of one phase in laboratory scale. It was used a reactor with a 8.77 L of useful volume, a medium support for corrugated conduit of polyvinyl chloride (PVC), temperature of 261 ºC, fed with cassava wastewater and glycerin, with hydraulic detention times of 4 and 5 days and increasing volumetric organic load of 3.05; 9.32; 14.83 and 13.59 g COD L-1 d-1, obtained with the addition of glycerin at 0; 2; 3 and 2% (v/v), respectively. The average removal efficiencies of TS and TVS were decreasing from the addition of glycerin to the cassava wastewater, averaging 81.19 to 55.58% for TS and 90.21 to 61.45% for TVS. The addition of glycerin at 2% increased the biogas production compared to the control treatment, reaching 1.979 L L-1 d-1. The biogas production as a function of the consumed COD was higher for the control treatment than for the treatments with addition of glycerin, which indicates lower conversion of organic matter into biogas.