Search

Essential oils (EO) are volatile compounds with complex chemical compositions that are derived from the secondary metabolism of aromatic herbs. There are several applications of EO in the industrial and medical sectors. Basil (Ocimum sp.) is one of the most important EO-producing aromatic herbs. In this study, EO content (EOC) and linalool content (LC) in basil irrigated with reclaimed water were investigated. Plant development parameters, nutrient absorption and crude protein (CP) content were also evaluated. The experiment was conducted in a greenhouse, with five different treatments and five repetitions each. Compared with treatments only using water, the results of those with reclaimed water irrigation showed higher nutrient absorption, CP contents (in their foliar tissue), length of plant branches, foliar biomass weights, and EOC and LC. EOC reached up to 0.58% of the dry biomass and LC was up to 5.84% of EO mass. In practice, it is estimated that around 5.8 kg of EO and 0.34 kg of linalool can be obtained from one ton of dry basil biomass. HIGHLIGHTS Higher essential oil and linalool contents were obtained in plants irrigated with higher percentage of reclaimed water used.; Reclaimed water use resulted in the highest length of branches and biomass production of dry leaves, up to 30 cm and 28 g per plant, respectively.; Crude protein content in leaves increased proportionally to the percentage of reclaimed water used.; Approximately 5.8 kg of EO and 0.34 kg of linalool can be obtained per ton of basil dry mass.

2,4-Dinitroanisole (DNAN) is a toxic compound increasingly used by the military that can be released into the environment on the soil of training fields and in the wastewater of manufacturing plants. DNAN's nitro groups are anaerobically reduced to amino groups by microorganisms when electron donors are available. Using anaerobic sludge as the inoculum, we tested different electron donors for DNAN bioreduction at 20 and 30 °C: acetate, ethanol, pyruvate, hydrogen, and hydrogen + pyruvate. Biotic controls without external electron donors and abiotic controls with heat-killed sludge were also assayed. No DNAN conversion was observed in the abiotic controls. In all biotic treatments, DNAN was reduced to 2-methoxy-5-nitroaniline (MENA), which was further reduced to 2,4-diaminoanisole (DAAN). Ethanol or acetate did not increase DNAN reduction rate compared to the endogenous control. The electron donors that caused the fastest DNAN reductions were (rates at 30 °C): H2 and pyruvate combined (311.28 ± 10.02 μM·d−1·gSSV−1), followed by H2 only (207.19 ± 5.95 μM·d−1·gSSV−1), and pyruvate only (36.35 ± 2.95 μM·d−1·gSSV−1). Raising the temperature to 30 °C improved DNAN reduction rates when pyruvate, H2, or H2 + pyruvate were used as electrons donors. Our results can be applied to optimize the anaerobic treatment of DNAN-containing wastewater. HIGHLIGHTS DNAN reduction was utterly dependent on sludge's biological activity.; Ethanol and acetate were ineffective electron donors compared to the endogenous condition.; The best electron donors were H2 combined with pyruvate, followed by H2 only and pyruvate only.; Increasing the temperature from 20 to 30 °C was a major game-changer when H2, pyruvate, or H2 + pyruvate were used as electron donors.

The use of batch and upflow anaerobic reactors filled with polyurethane foam for pure glycerol fermentation was evaluated. The best reactor operational conditions to obtain high yield and productivity of 1,3-propanediol (1,3-PDO) as the main product and the role of the polyurethane foam in the growth and retention of suspended and attached biomass in the reactors were investigated. In the experiment at 30 °C with a batch reactor (700 mL), biomass growth was mostly as immobilized attached cells, and the achieved 1,3-PDO yield was up to 0.58 mol mol-gly−1. In the experiment (30 °C) with an upflow anaerobic reactor (717 mL), glycerol loading rates (gly-LR) ranging from 6.94 to 15.47 g gly L−1 day−1 were applied during a 102-day period. During the operation, average 1,3-PDO yield was 0.47 mol mol-gly−1, reaching a maximum of 0.51 mol mol-gly−1 at gly-LR of 13.57 g gly L−1 day−1. High 1,3-PDO productivity (5.35 to 5.44 g L−1 day−1) was obtained when gly-LR was 13.57 to 15.47 g gly L−1 day−1. Comparing the close yield values in both batch and continuous reactors and based on microbial evaluation, it is concluded that most of the 1,3-PDO generated in the continuous reactor was due to the suspended biomass retained by the foam cubes. The Clostridium genus was the predominant 1,3-PDO producer. Good yields and productivities with packed reactors were attributed to polyurethane foam used for mixed culture growth and retention. Consequently, they are worth considering for 1,3-PDO production from pure glycerol.

In this work, cassava wastewater was used to evaluate hydrogen production and the subsequent production of caproic acid via acetate carbon chain elongation, adding ethanol as electron donor. Batch reactors were operated with an initial chemical oxygen demand of 10 and 20 g O2/L (A10 and A20, respectively), under self-fermentative operation at 40 ± 1 °C. The initial pH was set to 5.5 to inhibit methanogens growth. Hydrogen production yields were 1.01 and 1.98 mol H2/mol glucose for A10 and A20, respectively. In both cases, the main metabolites were ethanol and acetic, butyric, propionic, and caproic acids during the fermentative step; when adding ethanol for the chain elongation the pH was adjusted to 7.0 using a 2-M NaOH solution. The maximum total caproic acid concentration obtained after ethanol addition was 4.2 and 7.2 g/L for A10 and A20, respectively; of which 84% and 90% resulted from the carbon chain elongation step, respectively.

Glycerol from biodiesel production was used as a substrate for valerate production in a 13.1-L anaerobic filter with an open microbiome. Ethanol at 15% of the influent chemical oxygen demand was supplemented as an additional electron donor source. The 114-day experimental period was divided in three phases which included initial adaptation phase, external sludge addition from a caproic acid producing reactor and valerate extraction using a pertraction system. Propionate (0.63–1.75 g COD L−1 day−1) and valerate (0.86–1.81 g COD L−1 day−1) were the main carboxylates formed throughout all operational phases. An increase in production rates of butyrate (0.26–0.31 g COD L−1 day−1), caproate (0.01–0.08 g COD L−1 day−1), and 1,3-propanediol (0.43–0.52 g COD L−1 day−1) was observed with addition of external caproic acid producing sludge rich in Clostridium members. In the operational phase with pertraction, a sudden decrease in 1,3-propanediol and concomitant increase in acid production were verified. Propionate and valerate reached higher production rates compared with the other two phases, suggesting that the pertraction system favored the oxidative pathway of glycerol fermentation. Valerate extraction reached a maximum of 30 g COD m−2 day−1. The filter microbiome was highly diverse with Simpson index values close to 0.1 for the four sludge samples collected, and a concomitant increase in Megasphaera elsdenii and an increase in valerate production rates were observed. Hence, high valerate production and extraction rates through the carboxylate platform are a feasible alternative for crude glycerol valorization with a great potential for improvement in future research.

RESUMO Neste trabalho, avaliou-se o uso do modelo matemático ASM3 para um sistema piloto de reator compartimentado anaeróbio/anóxico e aeróbio tipo MBBR, utilizado para a remoção simultânea de matéria orgânica e nitrogênio em esgoto doméstico. A simulação computacional foi implementada pelo software ASIM. Selecionou-se um conjunto padrão de parâmetros para o modelo, com uma combinação dos valores calibrados e dados da literatura. Com a modelagem computacional foi possível incluir as características operacionais próprias do sistema de tratamento e, embora o modelo não tenha tido sua capacidade de previsão dos parâmetros validada, foi possível verificar a aplicabilidade do ASM3 para as fases operacionais definidas neste estudo. ABSTRACT In this work, the use of the ASM3 mathematical model for a pilot system of anaerobic/anoxic and aerobic MBBR compartmentalized reactor, for the simultaneous removal of organic matter and nitrogen in domestic sewage, was evaluated. The simulation was implemented by the ASIM software. A standard set of parameters was selected for the model, with a combination of calibrated values and literature data. With the computational modeling, it was possible to include the operational characteristics of the treatment system and, although the model capacity to predict the parameters could not be validated. Nevertheless, it was possible to verify the applicability of the ASM3 model for the operational phases defined in this study.

The effect of six important factors on the anaerobic biodegradation of linear alkylbenzene sulphonate (LAS) was evaluated using a response surface methodology. The factors were: (i) co-substrate concentration (CC), (ii) contact time between LAS and microorganisms, (iii) temperature, (iv) hardness, (v) pH, and (vi) LAS source. The results showed that individually or combined, CC with chemical oxygen demand (COD) ≤50 mg L

Resumo Com o presente estudo objetivou-se avaliar a qualidade físico-química e bacteriológica da água usada na irrigação de hortaliças em área de agricultura urbana, localizada no contorno rodoviário da BR-101 sul, na cidade do Recife. Para isto, coletaram-se amostras de água em seis poços existentes na área agrícola. As águas foram coletadas durante o período seco (outubro a dezembro de 2003) e os principais parâmetros físico-químicos (CEa, Ca++, Mg++, Na+, K+, Cl-, HCO3-, N-NO-3, N-NH4, pH e RAS e bacteriológico (coliforme fecal) foram analisados. A qualidade físico-química das águas de irrigação não apresentou risco de salinização e/ou alcalinização dos solos, nem de toxicidade específica às plantas. Abstract In the present study, the objective was to evaluate the physical-chemical and bacteriological quality of the water used for vegetable irrigation in an urban agricultural area at a cross road of BR-101 South in the city of Recife. Water samples were collected in six wells in the agricultural area. The water was collected during the dry season (October through December 2003) and the main physical-chemical characteristics (ECw, Ca++, Mg++, Na+, K+, Cl-, HCO3-, N-NO-3, N-NH4, pH and SAR) and bacteriological (fecal coliform) parameters were analyzed. The physical-chemical quality of the irrigation water did not present risk of soil salinization nor alkalinization, and neither any specific toxicity for the plants.

In this study, start-up strategies to develop conventional aerobic granular sludge (AGS) and algal aerobic granular sludge (AAGS) (photogranules), were investigated. The granulation experiment was conducted in four sequencing batch reactors (SBR), of which two were conventional SBRs (RC1, RC2) used as control, and two were photo-SBRs (R1, R2). R1 and RC1 were operated with a 40-min feeding during the reactors´ anaerobic cycle period, whereas R2 and RC2 with a 60-min feeding. All the reactors were operated in two phases with a C:N = 4:1 in Phase I and 8:1 in Phase II. In Phase I, AGS in RC1 and RC2 was formed 15 days before the AAGS development in R1 and R2. However, the AAGS generally presented better stability and higher diameter. On the other hand, AGS presented greater abundance of extracellular polymeric substances producing organisms, such as Xanthomonadacea and Rhodocyclaceae. Chemical oxygen demand (COD) and NH

RESUMO A remoção de matéria orgânica e de nitrogênio em esgoto doméstico diluído foi avaliada em dois reatores híbridos, um anaeróbio (RHAN) e outro aeróbio (RHAE). O RHAN era formado por uma câmara tipo upflow anaerobic sludge blanket sobreposta por outra de filtro anaeróbio, enquanto o RHAE tinha uma câmara de lodo ativado sobreposta por outra de biofilme aerado submerso. A operação do sistema foi dividida em duas fases, FI e FII, com razões de recirculação de 50 e 75% e duração de 94 e 110 dias, respectivamente. Para a remoção de nitrogênio, o RHAE foi operado com oxigênio dissolvido de 3,0 mg.L-1. A técnica da reação em cadeia da polimerase foi empregada tanto para o lodo suspenso das câmaras inferiores, como para o biofilme aderido nas câmaras superiores, para identificar a presença de micro-organismos desnitrificantes e nitrificantes. As maiores eficiências de remoção em termos de demanda química de oxigênio e nitrogênio total foram obtidas em FII, sendo 91% e ~50%, respectivamente; as concentrações no efluente foram ~40 mg O2.L-1 e ~15 mg N-NT.L-1. A presença de três grupos de bactérias, as desnitrificantes, as oxidantes de amônia e as oxidantes de nitrito, foi confirmada no biofilme aderido do RHAE, indicando uma biomassa mixotrófica e sugerindo a possibilidade do processo de nitrificação e desnitrificação simultânea. ABSTRACT The removal of organic matter and nitrogen in diluted domestic sewage was evaluated in two hybrid reactors, one anaerobic (ANHR) and another aerobic (AEHR). ANHR was formed by a upflow anaerobic sludge blanket (UASB)-type chamber overlaid by an anaerobic filter, while AEHR had an activated sludge chamber overlaid by a submerged aerated biofilm chamber. The experimental period was divided into two phases, FI and FII, with recirculation ratios of 50 and 75%, and duration of 94 and 110 days, respectively. For nitrogen removal, AEHR was operated with a 3.0-mg.L-1 dissolved oxygen. Polymerase chain reaction technique was used for both suspended sludge in the down-chambers and attached biofilm in the upper-chambers, to identify the presence of denitrifying and nitrifying microorganisms. The highest removal efficiencies in terms of chemical oxygen demand and total nitrogen were obtained in FII, being 91 and ~50%, respectively; effluent concentrations were ~40 mg O2.L-1 and ~15 mg N-TN.L-1. The presence of three groups of bacteria, the denitrifiers, the ammonia oxidants and the nitrite oxidants, was confirmed in the attached biofilm of the RHAE, indicating a mixotrophic biomass and suggesting the possibility of simultaneous nitrification and denitrification process.

The effects of discontinuous micro-aeration on the biotransformation of the tetra-azo dye Direct Black 22 (DB22) and of its anaerobic by-products (aromatic amines) were tested using sequencing batch reactors. The experimental set-up consisted of three independent reactors (R1, R2, and R3) working with distinct cycles: R1 was completely anaerobic, while both R2 and R3 included a micro-aerated stage after an anaerobic stage (R2 continuously and R3 intermittently micro-aerated). Average DB22 removal efficiencies in R1, R2, and R3 were 81.4, 74.5 and 76.8%, respectively. R1 produced an effluent with high acute ecotoxicity (1.13% as effective concentration causing 50% of bioluminescence inhibition in Vibrio fischeri) due to aromatic amines accumulation. In contrast, no acute ecotoxicity was detected in the effluent of R2 and R3, reflecting aromatic amines removal. At the anaerobic stage of the cycle, R2 and R3 showed DB22 decolorization rates 73 and 123% higher than R1, respectively. At the same time, the corresponding values of estimated methane production were 35 and 37% lower. Thus, oxygen apparently changed the balance between methanogenesis and reductive decolorization, inhibiting the first process and enhancing the second.

Insensitive munitions compounds, such as 2,4-dinitroanisole (DNAN), are replacing conventional explosives. DNAN is anaerobically reduced to 2,4-diaminoanisole (DAAN), a toxic aromatic amine. However, the removal of DAAN under different redox conditions is yet to be elucidated. Herein, we analyzed DAAN consumption in biotic and abiotic microcosms when exposed to different redox conditions (without added electron acceptor, without added electron acceptor but with pyruvate as a co-substrate, with sulfate, with nitrate, and with oxygen), using an anaerobic sludge as inoculum. We observed that DAAN autoxidation, an abiotic reaction, was significant in microaerobic environments. DAAN also reacted abiotically with heat-killed sludge up to a saturation limit of 67.4 μmol DAAN (g VSS heat-killed sludge)−1. Oxygen caused the fastest removal of DAAN in live sludge among the conditions tested. Treatments without added electron acceptors (with or without pyruvate) presented similar DAAN removal performances, although slower than the treatment with oxygen. Sulfate did not exhibit any effect on DAAN removal compared to the treatment without added electron acceptors. Nitrate, however, inhibited the process. An enrichment culture from the microcosms exposed to oxygen could be developed using DAAN as the sole substrate in microaerobic conditions. The enrichment profoundly changed the microbial community. Unclassified microorganisms accounted for 85% of the relative abundance in the enrichment culture, suggesting that DAAN microaerobic removal might have involved organisms that were not yet described. Our results suggest that DAAN microaerobic treatment can be coupled to DNAN anaerobic reduction in sludge, improving the treatment of DNAN-containing wastewaters.

The use of batch and upflow anaerobic reactors filled with polyurethane foam for pure glycerol fermentation was evaluated. The best reactor operational conditions to obtain high yield and productivity of 1,3-propanediol (1,3-PDO) as the main product and the role of the polyurethane foam in the growth and retention of suspended and attached biomass in the reactors were investigated. In the experiment at 30 °C with a batch reactor (700 mL), biomass growth was mostly as immobilized attached cells, and the achieved 1,3-PDO yield was up to 0.58 mol mol-gly

In the present study, we evaluate the behavior of real textile wastewater treatment using a system composed of two sequential pilot-scale reactors (anaerobic followed by aerobic) during 622 days. The work focused on the competition between color and sulfate removal processes, when the hydraulic retention time (HRT) was increased in the anaerobic/aerobic reactors from 16/12 hours in phase I (PI) to 4/3 days in phase II (PII). The organic matter was successfully removed in both phases through the system, and the highest efficiency (75%) was achieved in PII. The increase in the HRT did not improve azo dye degradation under anaerobic conditions. Instead, it favored sulfate reduction, which removal efficiency increased from 26% in PI to 75% in PII. Aromatic amines were detected in the anaerobic reactor effluent and removed in the aerobic reactor.

Avaliou-se o uso de esgoto tratado em reator anaeróbio para irrigação por gotejamento, combinado com diferentes níveis de adubação química, no cultivo de melancia em região semiárida. Foram estudados quatro tratamentos, com 0%, 25%, 50% e 100% da adubação química recomendada. As médias de produtividade de todos os tratamentos variaram de 43,3 t/ha a 53,7 t/ha, sendo maior que a média no país (22,5 t/ha). Os frutos mais pesados e maiores foram obtidos nos tratamentos com 25% e 50% da adubação recomendada, mas não houve diferença significativa em relação ao tratamento com 0%. Portanto, a utilização de esgoto tratado sem adubação é a forma recomendada para a cultura da melancia. As características de alta produtividade (43,3 t/ha) e de sólidos solúveis (6,63 °Brix) indicam atratividade econômica e fruto doce, com potencial de boa aceitação comercial.

The 1,3-propanediol (1,3-PDO) yield and productivity from glycerol were studied over a 155-day period. A UASB reactor that also contained silicone support for biomass attachment was used to evaluate the optimal operational conditions and microbiota development. The highest average 1,3-PDO yield was 0.54 and 0.48 mol.mol-gly−1 when reactor pH was 5.0–5.5 and the applied loading rate was 18 and 20 g-gly.L−1.d−1 using the pure and crude substrate, respectively. The productivity was close to 7.5 g.L−1.d−1 for both substrates; therefore, the direct use of crude glycerol can be valorized in practice. Clostridium was the predominant genus for 1,3-PDO production and C. pasteurianum was dominant in the biofilm. Using crude glycerol, C. beijerinckii dropped strongly; some Clostridium population was then replaced by Klebsiella pneumoniae and Lactobacillus spp. The good process performance and the advances in the microbiota knowledge are steps forward to obtain a more cost-effective system in practice.

The aim of the present study was to assess the bioremediation of estuarine sediments contaminated with diesel oil. The following two experiments were performed: natural attenuation (NA) and stimulated natural attenuation (SNA), using rhamnolipid as biosurfactant. Sediment samples were accommodated into glass columns and then contaminated with diesel oil on the top. The column profiles were separated into surface, middle, and bottom for the analyses. The 16 polycyclic aromatic hydrocarbons (PAHs) prioritized by US Environmental Protection Agency (EPA) were monitored for 349 days. Those with three and four rings showed increasing concentrations through the operation period in the middle and bottom samples, particularly between days 111 and 338, and in the SNA experiment. Those with five and six rings were also detected in the deeper portions of the columns, suggesting the percolation of PAHs with a high molecular weight. Total organic carbon was reduced by 91 and 89 % in the NA and SNA samples, respectively, although no statistically significant differences (p > 0.05) were found between the two treatments. The analyses by denaturing gradient gel electrophoresis indicated a slight shift in the microbial community structure over the experiments. Microorganisms belonging to the γ-Proteobacteria phylum were the main bacteria involved. The archaeal community exhibited dominance of hydrogenotrophic methanogens, indicating the obligate anaerobic biodegradation of intermediate compounds from hydrocarbon degradation.

In northeastern Brazil, stabilization ponds are very suitable for wastewater treatment because of the relative great land availability and environmental conditions (e.g., high temperature) favorable for microorganism optimal development. However, blooms of potentially toxic cyanobacteria may affect the use of these treatment ponds due to resulting effluent poor quality. The objective of this study was to evaluate the dynamics of phytoplankton communities and the occurrence of cyanobacteria in a maturation pond located immediately after a series of two ponds. Temperature, dissolved oxygen, pH, BOD, N, and P were measured during a period of four months when samples were collected from the surface and the bottom of 7 sampling points distributed inside the pond. The phytoplankton of collected samples was also identified and classified using a conventional optical microscopy. Analysis of variance and Tukey test were used to evaluate the results. The three phytoplankton divisions found (Cyanophyta, Chlorophyta, and Euglenophyta) did not change considerably through surface and bottom. However, they changed greatly over the sampled months; great dominance of Cyanophyta was found at April and October, while Chlorophyta dominated the lagoon in September. Low superficial organic loads (between 78 and 109 kg BOD.ha–1.d–1) and N:P ≤ 10 were the determinant factors that favored the predominance of Cyanophyta. The presence of two potentially toxic species of Cyanophyta, Oscillatoria sp. and Microcystis aeruginosa, indicates that caution is required when considering the final destination of treated effluent and suggests a need to assess the risks and benefits associated with the use of the treatment technology. Resumo No nordeste do Brasil, as lagoas de estabilização são muito adequadas para o tratamento de águas residuárias por causa da disponibilidade relativamente grande de terra e das condições ambientais (por exemplo, altas temperaturas) favoráveis ao melhor desenvolvimento dos microorganismos. Entretanto, florações de cianobactérias potencialmente tóxicas podem afetar o uso dessas lagoas de tratamento, devido à consequente qualidade inferior do efluente. O objetivo deste estudo foi avaliar a dinâmica das comunidades de fitoplâncton e a ocorrência de cianobactérias em uma lagoa de maturação situada após duas lagoas em série. Temperatura, oxigênio dissolvido, pH, DBO, N e P foram medidos durante um período de quatro meses, durante o qual amostras foram coletadas na superfície e fundo em sete pontos de amostragem da lagoa. As comunidades de fitoplâncton das amostras coletadas foram também identificadas e classificadas utilizando-se um microscópio óptico convencional. Para avaliar os resultados utilizou-se a análise de variância e o teste de Tukey. Para as três divisões de fitoplâncton encontradas (Cyanophyta, Chlorophyta e Euglenophyta), não houve diferença significativa para as amostras de superfície e de fundo de um mesmo mês. Entretanto, ocorreu grande variação para as amostras dos diferentes meses; nos meses de abril e outubro houve uma predominância de Cyanophyta, ao passo que em setembro o predomínio na lagoa foi de Chlorophyta. Os fatores determinantes que favoreceram o predomínio de Cyanophyta foram a baixa carga orgânica superficial aplicada (entre 78 e 109 kg DBO.ha–1.d–1) e N:P ≤ 10. A presença de duas das espécies de Cyanophyta, Oscillatoria sp. e Microcystisaeruginosa, consideradas potencialmente tóxicas, indica que é necessária precaução quando se considera o destino final do efluente tratado e sugere a necessidade de avaliar os riscos e benefícios associados ao uso da tecnologia de tratamento.

Sequential anaerobic and aerobic processes have been recommended to treat textile wastewater reliably. In this work, the focus was on finding an energetically more competitive system to remove tetra-azo dye Direct Black 22 (DB22). We operated two upflow anaerobic sludge blanket (UASB) reactors (R1 and R2) in three phases (PI, PII, and PIII). R1 was operated as a conventional UASB, while R2 was microaerated in the upper part (0.18 ± 0.05 mg O2. L−1), aiming to remove DB22 simultaneously with the aromatic amine byproducts. PI consisted of feeding reactors with synthetic textile wastewater (STW), PII had higher salinity in the STW, and PIII was the same as PII, plus sulfate. The results showed that color and COD removal efficiencies were similar for both reactors (67–72% for R1 and 59–78% for R2) without a substantial influence of oxygen in R2. However, microaeration played a crucial role in R2 by removing the anaerobically formed aromatic amines; during PIII, the effluent was 16 times less toxic than that of R1. The microbial community that developed in the sludge bed of both reactors was quite similar, with the core microbiome represented by Trichococcus, Syntrophus and Methanosaeta genera. The increase in salinity in PII and PIII promoted a shift in the microbial community, excluding salty-sensitive genera from the core microbiome. The putative genera Brevundimonas and Ornatilinea were associated to aromatic amine microaerobic removal. Therefore, there is a potential application of a compact microaerated anaerobic system for textile wastewater treatment.

RESUMO O objetivo deste trabalho foi avaliar a viabilidade agronômica do uso de esgoto doméstico tratado em reator anaeróbio para o cultivo de melancia tipo Crimson Sweet. Em estudo de campo no Sertão Pernambucano, avaliou-se a aplicação de quatro lâminas de irrigação por meio do sistema de gotejamento. Foram avaliadas as lâminas de 50, 75, 100 e 125% baseadas nos resultados da evapotranspiração e nas exigências do sistema de irrigação adotado. A caracterização do efluente tratado indicou conformidade com as recomendações para a aplicação agrícola, entretanto a concentração de sólidos suspensos (114 mg.L-1) demandou maior frequência de limpeza dos gotejadores. Foram observados um aumento da capacidade de troca catiônica e uma redução do pH do solo em todos os tratamentos. O tratamento com lâmina a 125% resultou em frutos de maiores tamanho (20,78 cm) e peso (7,12 kg.un-1), bem como de produtividade média (61,1 t.ha-1). Estes valores são superiores às médias nacional e do Estado de Pernambuco, demonstrando a viabilidade agronômica do reúso nas condições testadas. ABSTRACT The aim of this paper was to assess the agronomic viability of using anaerobically treated domestic sewage in cultivation of Crimson Sweet watermelon. In a field experiment conducted in the semi-arid region of Pernambuco state, Brazil, four treatments (T) were used to assess the effects of irrigation using dripping system on fruits and soil. Four heights of 50% (T1), 75% (T2), 100% (T3) and 125% (T4), based on the calculated evapotranspiration and irrigation needs, were applied. The treated effluent characteristics indicated compliance with the recommendations for agricultural application, but the concentration of suspended solids (114 mg.L-1) demanded frequent cleansing of the dripper blockages. We observed an increase in the cation exchange capacity and a decrease of the soil pH in all the treatments. The best results were obtained with the treatment T4 (height of 125%), which showed watermelons of bigger size (20.78 cm), as well as the highest productivity (61.1 t.ha-1) and fruit weight (7.12 kg.un-1). These values are higher than those of the country and Pernambuco state, demonstrating the agronomic feasibility of reuse under the studied conditions.

The decision-making process involved in municipal solid waste management (MSWM) must consider more than just financial aspects, which makes it a difficult task in developing countries. The Recife Metropolitan Region (RMR) in the Northeast of Brazil faces a MSWM problem that has been ongoing since the 1970s, with no common solution. In order to direct short-term solutions, three MSWM alternatives were outlined for the RMR, considering the current and future situations, the time and cost involved and social/environmental criteria. A multi-criteria approach, based on the Preference Ranking Organization Method for Enrichment Evaluations (PROMETHEE), was proposed to rank these alternatives. The alternative that included two private landfill sites and seven transfer, sorting and composting stations was confirmed as the most suitable and stable option for short-term MSWM, considering the two scenarios for the criteria weights. Sensitivity analysis was also performed to support the robustness of the results. The implementation of separate collections would minimize the amount of waste buried, while maximizing the useful life of landfill sites and increasing the timeframe of the alternative. Overall, the multi-criteria analysis was helpful and accurate during the alternative selection process, considering the similarities and restrictions of each option, which can lead to difficulties during the decision-making process.

The influence of sludge discharge frequency on the performance of a full-scale UASB-type reactor has been assessed. The reactor has eight compartments and treats domestic sewage with an 8 hour hydraulic retention time. In each compartment, a different discharge frequency was employed ranging from 1 to 8 months. During the assessment period, the chemical oxygen demand (COD) removal efficiency, effluent volatile suspended solids (VSS) concentration, and cellular yield coefficient (Y) were evaluated. The results indicated that the operational stability increased with increasing discharge frequency, as shown by a higher COD removal and lower effluent VSS. The values of Y decreased when the sludge discharge frequency increased. In practice, good performance can be achieved when the sludge discharge frequency is between 1 and 4 months; COD removal efficiencies of 60–80%, average VSS effluent concentrations of 25–80 mg L−1, and Y values of 0.10–0.18 kg VSS kg CODremoved−1 were obtained.

The procedures to implement a chromatographic method for the quantification of linear alkyl benzene sulfonate (LAS) in the influent, effluent and sludge of a wastewater treatment plant (WWTP), and in river water and sediment, are described and evaluated. The columns octylsilane (C8) and octadecylsilane (C18) for high performance liquid chromatography were evaluated for separation of LAS homologues. The results showed that both columns separated the four homologues, but C18 was better for separation of the isomers of each homologue. This enabled to qualitatively evaluate the degradation of homologues in the WWTP, according to their respective isomers. Samples pre-treatment by solid phase extraction (SPE) columns, strong anionic exchange (SAX) and C18, was also evaluated. SPE was necessary for water river samples, either to concentrate LAS or to remove interference in the matrix; however, for WWTP samples, SPE showed unnecessary. The recovery of LAS homologues, after the procedures for sample preparation, was 90 to 110% with an accuracy of 1 to 5%. The WWTP was efficient in LAS removal from domestic sewage; however, the concentrations in water and sediments of the receiving body were higher than the limits established by legislation due to illegal discharges of untreated sewage.

RESUMO: Avaliou-se a degradação anaeróbia do alquilbenzeno linear sulfonato (LAS) e seus homólogos em experimento em escala de laboratório. Foi usado lodo disperso para minimizar o efeito da adsorção. Em primeiro lugar, determinaram-se a maior concentração de LAS (substrato) e a menor concentração de etanol (cossubstrato) que manteriam os micro-organismos ativos, resultando em 25 e 200 mg.L-1, nessa ordem. Posteriormente, o experimento (90 dias) foi realizado em um reator somente com etanol (controle) e outro (reator teste, triplicata) com ambos os substratos nas concentrações anteriores. Os micro-organismos apresentaram crescimento exponencial em 48 h para os 2 reatores; não ocorreu toxicidade pelo LAS no reator teste durante esse período inicial, quando o etanol foi todo consumido. Após então, houve decréscimo de micro-organismos, indicando possível toxicidade por LAS ou intermediários. Observou-se também a diminuição ou ausência da produção de ácidos graxos voláteis e de metano. Portanto, com lodo disperso, a maior parcela da remoção foi por conta da biodegradação, porém, com formação de intermediários que não o acetato nem o metano, apontando a inibição à acidogênese e à metanogênese. Ao final, a remoção do LAS foi de 35% por biodegradação e apenas 0,35% por adsorção ao lodo. A ordem preferencial de biodegradação para os homólogos foi de C13 para C12, C11 e C10, com percentual de degradação em relação à massa inicial de 49, 31, 24 e 17%, respectivamente. A mesma ordem deu-se para a adsorção, da maior para a menor cadeia alquílica, sendo a remoção por adsorção de 0,85; 0,32; 0,13 e 0,01%, respectivamente. ABSTRACT: The anaerobic degradation of linear alquibenzene sulfonate (LAS) and its homologues was evaluated in batch experiment. Dispersed sludge was used to minimize the effect of adsorption. Initially, the highest concentration of LAS (substrate) and the lowest concentration of ethanol (co-substrate) were determined to maintain the microorganisms active; the results were 25 and 200 mg.L-1, respectively. Afterwards, a 90-day period experiment was conducted with one reactor with only the addition of ethanol (control) and the other (test reactor in triplicate) with both substrates and the previous concentrations found. The microorganisms showed exponential growth in the first 48 h for both reactors; LAS toxicity has not occurred in the test reactor during the first 4 days, during which ethanol was consumed. After that, the microorganisms decreased, indicating possible toxicity due to LAS or intermediates; a decrease or absence of volatile organic acids and methane production was also observed. Therefore, with dispersed sludge the largest removal was due to biodegradation, but with formation of intermediates other than acetate or methane, indicating inhibition of acidogenesis and methanogenesis. At the end, the removal was 35% by biodegradation and only 0.35% by adsorption to the biomass. The preferential order of the biodegradation for the homologues was from C13 to C12, C11 and C10; and the removal in relation to the initial mass of each was 49, 31, 24 and 17%, respectively. The same order occurred to adsorption, from the higher to the lower alkyl chain, with removal of 0.86, 0.32, 0.13 and 0.01%, respectively.

Manipueira is a carbohydrate-rich agro-industrial waste from cassava processing. It is considered well suitable for biotechnological processes, such as hydrogen and carboxylic acids production, due to the high content of easily degradable organic matter. However, the proper methanogenesis inhibition method, inoculum type, and organic loads are factors still limiting the processes. The objective in this work was to evaluate the effects of such factors on byproducts production in anaerobic reactors. Batch experiments were conducted with 2.3-L flasks during two operational phases. In the first phase (P1), inhibition of methanogens in the sludge was evaluated using acetylene (1% v/v of headspace) and heat treatment (120 °C, 1 atm for 30 min). In the second phase (P2), three inoculum types obtained from common anaerobic sludges (bovine rumen and sludges from municipal and textile industrial wastewater treatment plants) were individually assayed. P2 aimed to identify the best inoculum, based on hydrogen production ability, which was tested for three initial concentrations of manipueira in terms of chemical oxygen demand (COD) (10, 20 and 40 g O2/L). Results of P1 indicated that either acetylene or heat treatment efficiently inhibited methanogenesis, with no methane production. However, the maximum H2 production potential by applying heat treatment (~ 563 mL) was more than twice compared with that by acetylene treatment (~ 257 mL); and butyrate was the main carboxylic acid by-product (~ 3 g/L). In P2 experiments after sludge heat treatment, the highest hydrogen yield (1.66 ± 0.07 mol H2/mol glucose) and caproic acid production (~ 2 g/L) were observed at 20 g O2/L of manipueira COD, when bovine rumen was the inoculum. The primary metabolic degradation products in all P2 experiments were ethanol, acetic, butyric, propionic and caproic acids. The finding of caproic acid detection indicated that the applied conditions in manipueira anaerobic degradation favored carbon chain elongation over methanogenesis.

Rivers are important ecosystems that are integrated into biogeochemical cycles and constitute an essential resource for numerous human uses. However, the assessment of the biological diversity and composition of microbial communities found in rivers remains incomplete, partly due to methodological constraints which are only recently being resolved with the advent of next generation sequencing (NGS) techniques. Using 454-pyrosequencing of the 16S gene, the present study analyzed the microbial diversity of the planktonic and sediment populations in a tropical river in northeastern Brazil that is exposed to severe pollution. Six water and six sediment samples were analysed. The dominant bacterial phyla in both sediment and water were the Proteobacteria, followed by Bacteroidetes and Actinobacteria in the water column and by Chloroflexi and Acidobacteria in the sediment. Biological diversity appeared to be greatly decreased by environmental pollution, whereas the microbial community structure was variable across the analyzed transect. Moreover, a narrow relationship between industrial and urban sources of contamination and the bacterial genera detected at these sites has been observed. A variety of potentially pathogenic bacteria was detected, including Klebsiella, Treponema, Faecalibacterium and Enterococcus, indicating that the river might pose a substantial risk to public health. [Int Microbiol 20(1): 11-24 (2017)].

An upflow anaerobic sludge blanket (UASB)–submerged aerated biofilter (SAB) system was evaluated to remove color and chemical oxygen demand (COD) from real textile effluent. The system was operated for 335 days in three phases (P-1, P-2, P-3) with total hydraulic retention time varying from 21 h to 14 h. The results showed that high sulfate levels (>300 mg SO42−/L) impaired the dye reduction. The best color removal efficiencies of 30% and 96% for the UASB and the reactor system, respectively, were obtained in P-1; the SAB higher efficiency was associated with adsorption. The best COD removal efficiency of 71% for the reactor system was obtained in P-2. Precipitation of some material composed mostly of sulfur (98%) and some metals occurred in the UASB. However, the precipitated sulfur was again oxidized in the SAB. The system also showed an effective toxicity reduction in tests (Daphnia magna) with the treated effluent.

QUALITY CONTROL PROGRAM USED IN LABORATORY OF EDUCATION AND RESEARCH IN ENGINEERING The Program 5-S (senses) is a tool for quality control that has been used during the last seven years in a laboratory of education and research of civil engineering for undergraduate and graduate students. This paper presents and discusses the results of experience with this program at the Laboratory of Environmental Sanitation of the Federal University of Pernambuco (LSA-UFPE). A special emphasis was given to the main difficulties and the many benefits obtained for the teaching-learning process. Aware of the new demands of the labor market imposed on the engineering and related professionals, the LSA-UFPE seeks to extend its area of activity. In this perspective, is not restricted to analytical and experimental activities, seeking to develop in the students the cognitive skills, specialized techniques and behavioral and attitudinal abilities, as follow: cooperation, initiative, entrepreneurship, motivation, responsibility, participation, discipline and permanent attitude of learning to learn.

Color removal was evaluated in anaerobic assays using synthetic (SE) and real (RE) effluents containing the dye Direct Black 22 (DB22). The focus was on the individual influence of two electron donors (EDs), sucrose and ethanol; and their combination with two redox mediators (RMs), lawsone and riboflavin. In addition to SE assays, the EDs were combined with sulfate which was present in the RE. Distinct behavior was observed with both assays. In the case of SE, using the EDs sucrose and ethanol resulted in DB22 removal efficiency of 93 and 83%, respectively; but only 27% in the control. The respective removal rates were 27.8- and 4.4-fold higher than that of the control. Using the EDs with the RM lawsone resulted in color removal higher than that with riboflavin. Interestingly, in the ethanol + sulfate assay, late release of the last was observed, possibly due to the desulfonation reaction of the aromatic structures during the DB22 molecule breakdown. In the case of RE, no improvement was observed with either EDs; and some combinations with the RMs even resulted in decreased color removal. Therefore, the used EDs and RMs showed positive effect on color removal in SEs; but unexpectedly not in REs.

The removal of polyaromatic hydrocarbons (PAH) in tropical clay soil contaminated with diesel oil was evaluated. Three bioremediation treatments were used: landfarming (LF), biostimulation (BS) and biostimulation with bioaugmentation (BSBA). The treatment removal efficiency for the total PAHs differed from the efficiencies for the removal of individual PAH compounds. In the case of total PAHs, the removal values obtained at the end of the 129-day experimental period were 87%, 89% and 87% for LF, BS and BSBA, respectively. Thus, the efficiency was not improved by the addition of nutrients and microorganisms. Typically, two distinct phases were observed. A higher removal rate occurred in the first 17 days (P-I) and a lower rate occurred in the last 112 days (P-II). In phase P-I, the zero-order kinetic parameter (μg PAH g −1 soil d −1 ) values were similar (about 4.6) for all the three treatments. In P-II, values were also similar but much lower (about 0.14). P-I was characterized by a sharp pH decrease to less than 5.0 for the BS and BSBA treatments, while the pH remained near 6.5 for LF. Concerning the 16 individual priority PAH compounds, the results varied depending on the bioremediation treatment used and on the PAH species of interest. In general, compounds with fewer aromatic rings were better removed by BS or BSBA, while those with 4 or more rings were most effectively removed by LF. The biphasic removal behavior was observed only for some compounds. In the case of naphthalene, pyrene, chrysene, benzo[k]fluoranthene and benzo[a]pyrene, removal occurred mostly in the P-I phase. Therefore, the best degradation process for total or individual PAHs should be selected considering the target compounds and the local conditions, such as native microbiota and soil type.

Azo dyes, which are widely used in the textile industry, exhibit significant toxic characteristics for the environment and the human population. Sequential anaerobic-aerobic reactor systems are efficient for the degradation of dyes and the mineralization of intermediate compounds; however, little is known about the composition of the microbial communities responsible for dye degradation in these systems. 454-Pyrosequencing of the 16S rRNA gene was employed to assess the bacterial biodiversity and composition of a two-stage (anaerobic-aerobic) pilot-scale reactor that treats effluent from a denim factory. The anaerobic reactor was inoculated with anaerobic sludge from a domestic sewage treatment plant. Due to the selective composition of the textile wastewater, after 210 days of operation, the anaerobic reactor was dominated by the single genus Clostridium, affiliated with the Firmicutes phylum. The aerobic biofilter harbored a diverse bacterial community. The most abundant phylum in the aerobic biofilter was Proteobacteria, which was primarily represented by the Gamma, Delta and Epsilon classes followed by Firmicutes and other phyla. Several bacterial genera were identified that most likely played an essential role in azo dye degradation in the investigated system.

RESUMO: Avaliou-se a remoção do alquilbenzeno linear sulfonato (LAS) em uma estação de tratamento de esgoto (ETE) com reator tipo UASB e lagoa de polimento durante dois períodos, seco e chuvoso. A remoção de LAS também foi avaliada em uma das 8 células do UASB (810 m3). Nessa célula, a remoção, predominantemente por adsorção, foi de 68±52 e 0% para os períodos seco e chuvoso, respectivamente. A eficiência de remoção global do LAS na ETE foi de 80±15 a 98±3%, considerando os dois períodos sazonais. A concentração de LAS no efluente da lagoa de polimento ficou entre 0,1±0,3 e 0,6±0,3 mg.L-1. Portanto, a qualidade do efluente da ETE, em termos de LAS, foi muito satisfatória, com valores inferiores aos da legislação (

The effect of the initial concentration of linear alkylbenzene sulfonate (LAS) on specific methanogenic activity (SMA) was investigated in this work. Six anaerobic flasks reactors with 1 L of total volume were inoculated with anaerobic sludge (2 g VSS L(-1)). The reactors were assayed for 42 days, and fed with volatile fatty acids, nutrients, and LAS. The initial LAS concentrations were 0, 10, 30, 50, 75, and 100 mg L(-1) for the treatment flasks T1 (control), T2, T3, T4, T5, and T6, respectively. When compared with T1, T2 exhibited a 30% reduction in maximum SMA and total methane production (TMP). In treatment T3 through T6, the reductions were 44-97% (T3-T6) for SMA, and 30-90% (T3-T6) for TMP. Total LAS removal increased following the increase in the initial LAS concentration (from 36% at T1 to 76% at T6), primarily due to the high degree of sludge adsorption. LAS biodegradation also occurred (32% in all treatments), although this was most likely associated with the formation of non-methane intermediates. Greater removal by adsorption was observed in long-chain homologues, when compared to short-chain homologues (C13C10), whereas the opposite occurred for biodegradation (C10C13). The C13 homologue was adsorbed to a great extent (in mass) in T4, T5 and T6, and may also have inhibited methane formation in these treatments.

In this study, we evaluated the use of an up-flow anaerobic sludge blanket (UASB) reactor to treat crude glycerol obtained from cottonseed biodiesel production. The laboratory-scale UASB reactor (7.0 L) was operated at ambient temperature of 26.5°C with chemical oxygen demand (COD) concentrations between 0.5 and 8.0 g/L. The volatile fatty acid contents, pH, inorganic salt contents and biogas production were monitored during a 280-day experimental period. Molecular biology techniques were used to assess the microbial diversity in the bioreactor. The reactor achieved COD removal efficiencies of up to 92% except during one phase when the efficiency decreased to 81%. Biogas production remained stable throughout the experimental period, when the fraction converted to methane reached values as high as 68%. The profile of the denaturing gradient gel electrophoresis (DGGE) bands suggested slight changes in the microbial community during reactor operation. The overall results indicated that the crude glycerol from biodiesel production can serve as a suitable substrate for anaerobic degradation with a stable reactor performance and biogas production as long as the applied organic loads are up to 8.06 kg COD/m3·d.

Avaliou-se o cultivo de mudas de eucalipto da espécie urograndisirrigadas com esgoto doméstico tratado em estação com reator anaeróbio e lagoa de polimento. A irrigação das mudas, em vaso e com base na capacidade de pote (CP) para o solo, foi efetuada em experimento com seis tratamentos (T), com quatro repetições cada. Em T1, T2, T3 e T4, a irrigação com esgoto foi com lâmina a 100, 80, 60 e 40% do índice CP, respectivamente; em T5 e T6, a irrigação foi com água a 80% de CP. Apenas T5 teve adição de fertilizantes (NPK). Uma boa eficiência da estação de tratamento foi obtida durante os 3 meses de experimento, com remoção de demanda bioquímica de oxigênio, demanda química de oxigênio e helmintos de 90, 87 e 100%, respectivamente; portanto, com qualidade de efluente adequada para irrigação de arbóreas. Os desempenhos de T2 e T3 foram os melhores em termos de parâmetros de crescimento da planta (altura, diâmetro do caule, diâmetro da copa, número de folhas e matéria seca); comparativamente, em T2, acumulou-se mais nitrogênio nas folhas e caules. Os resultados obtidos mostram que o cultivo de mudas de eucalipto irrigadas com esgoto tratado, aproveitando os nutrientes e com lâminas adequadas (entre 80 e 60% do índice CP), é viável agronomicamente. The cultivation of Eucalyptus urograndis seedlings irrigated with domestic sewage effluent of a treatment plant with anaerobic reactor and polishing pond was evaluated. Seedling pots were irrigated based on the soil pot capacity (PC) in six treatments (T) with four repetitions each. The pots in T1, T2, T3 and T4 were irrigated with slide heights at 100, 80, 60 and 40% of the PC index, respectively; in T5 and T6, irrigation was only with water and slide heights at 80% of PC. Only T5 received additional nutrients (NPK). Along the experiment (3 months), the treatment plant showed good removal efficiencies of biochemical oxygen demand (90%), chemical oxygen demand (87%) and helminth eggs (100%); therefore, with adequate effluent quality for tree irrigation. T2 and T3 showed the best results in terms of plant development parameters, like height, stalk diameter, cup diameter, number of leaves and dry matter; comparatively, T2 showed the highest nitrogen accumulation in the leaves and stalks. The results show that cultivation of eucalyptus seedlings irrigated with treated sewage, taking advantage of the nutrients and with adequate slide heights (between 80 and 60% of PC index), is agronomically viable.

The aim of this study is to analyze the reaction of a particular mining company in terms of disclosure in Sustainability Reports regarding the news about environmental accidents in which it was involved, as a form of legitimation. According to Legitimacy Theory, companies seek voluntarily to disclose information as a way to legitimize their activities vis-a-vis society in an attempt to maintain the so-called “social contract” between businesses and society. Thus, we analyzed the Sustainability Reports of a Brazilian mining company from 2004 to 2010. The analysis was performed using the Alceste® discourse analysis program, and the results were analyzed together with the three environmental accidents involving the company. The results show a change in the discourse on sustainability in the reports after these environmental accidents. The topic of environmental preservation took the space previously dedicated to the description of operational activities. There was also a strengthening of other aspects of legitimation through the publication of reports on awards of an environmental nature, which did not occur in disclosures previous to the accidents. We conclude that the findings of this study corroborate those reported by Deegan et al. (2000), which is the paper that inspired this work, and the aspects advocated by the Theory of Legitimacy. Keywords: financial statements, Sustainability Report, Theory of Legitimacy.

Since the earlier anaerobic treatment systems, the design concepts were improved from classic reactors like septic tanks and anaerobic ponds, to modern high rate reactor configurations like anaerobic filters, UASB, EGSB, fixed film fluidized bed and expanded bed reactors, and others. In this paper, anaerobic reactors are evaluated considering the historical evolution and types of wastewaters. The emphasis is on the potential for application in domestic sewage treatment, particularly in regions with a hot climate. Proper design and operation can result in a high capacity and efficiency of organic matter removal using single anaerobic reactors. Performance comparison of anaerobic treatment systems is presented based mostly on a single but practical parameter, the hydraulic retention time. Combined anaerobic reactor systems as well as combined anaerobic and non-anaerobic systems are also presented.

Ponds following anaerobic reactors, such as Upflow Anaerobic Sludge Blanket (UASB) reactors, have been termed polishing ponds in the literature. The present paper analyses the removal of E. coli and helminth eggs in five UASB–polishing pond systems in Brazil. Since there were ponds in series, the total number of ponds was 10. The ponds had average retention times varying from 2 to 21 days, and depths ranging from 0.40 to 2.00 m. The shallow ponds in series, even with low retention times, were able to produce effluents complying with the coliform WHO guidelines for unrestricted irrigation (≤1000 MPN/100 ml). An equation for the coliform decay coefficient was proposed: Kb (dispersed flow)=0.710 H−0.955 (20 °C). The equation highlights the inverse relationship between the pond depth and the decay coefficient. All polishing pond systems were able to produce effluents with helminth eggs concentrations predominantly equal to zero, and satisfying the WHO guidelines for unrestricted and restricted irrigation (≤1 egg/L, arithmetic mean). The approximate range of helminth eggs removal efficiency was predicted satisfactorily.

The performance of an EGSB (expanded granular sludge bed) reactor type using flocculent sludge was evaluated for the post-treatment of effluent from UASB reactor treating domestic sewage. A pilot-scale 157.5-L EGSB reactor was monitored during a 331-day period. The original concept of the EGSB reactor was based on granular sludge use and by applying of high upflow liquid velocities (Vup). However, even using flocculent sludge from a UASB full-scale (Mangueira Plant, Recife, Brazil), good mixing conditions and high retention of biomass were achieved. By applying a 4-h hydraulic retention time and Vup values up to 3.75 m/h, effluent chemical oxygen demand concentrations in the EGSB were below 87 mg/L and 55 mg/L, for total and filtered samples, respectively. Total suspended solid (TSS) concentrations in the effluent were below 32 mg/L. Good performance and stable reactor operation during the whole experimental period were observed. Therefore, the EGSB reactor type using flocculent sludge can also be used for post-treatment of very dilute anaerobic effluent from reactors treating domestic sewage.

The Lagoon Olho d'Água in Pernambuco State, Northeast Brazil has received increasing environmental concern due to significant stress from pollution in the catchment. The existing environmental problems are the result of great pressure from a broad range of human activities, especially in the last 10 years. Serious pollution exists mainly from some industrial and urban activities, which increased intensively after the eighties. There is a strong social and economical pressure for housing and construction near the lagoon, due to the available land nearby beaches and estuarine zone, and recently by growing tourism activities. Uncontrolled land use by low-income communities and the pressure for construction by developers have led to landfilling and to deterioration of water quality in the lagoon catchment. Improvement of the environmental conditions in the catchment needs integrated measures. Guidelines and some specific actions involving several institutions have been established and refer to sanitation and urban infrastructure as the main priorities. A main target is the construction of low-cost sewage system with smaller and decentralised treatment plants. Keywords: Environmental program, Integrated measures, Lagoon Olho d'Água catchment, Sanitation, Small and decentralised plants, Urban expansion and infrastructure, Wastewater anaerobic treatment, UASB reactor, Water pollution