Occurrence and removal of drugs and endocrine disruptors in water supply systems in the metropolitan region of Belo Horizonte (Minas Gerais State, Brazil).

This study evaluates both the occurrence and removal of 24 compounds, including drugs and endocrine disruptors, in 8 water treatment plants (WTP) located in the metropolitan region of Belo Horizonte (Minas Gerais State, Brazil). The compounds 4-nonylphenol, 4-octylphenol, 17α-ethinylestradiol, 17ß-estradiol, acyclovir, bisphenol A, bezafibrate, caffeine, dexamethasone, diclofenac sodium, diltiazem, estrone, estriol, gemfibrozil, ibuprofen, linezolid, loratadine, losartan, metformin, naproxen, paracetamol, promethazine, propranolol and sulfamethoxazole were monitored at 3 sampling points (raw water, filtered water, treated water) over 10 or 12 collection campaigns for each WTP. The results showed that bisphenol A occurred at higher concentrations during the dry period with a maximum concentration of 3257.1 ng L-1, while the compounds 4-nonylphenol and losartan exhibited higher concentrations in the rainy period with maximum concentrations of 8577.2 ng L-1 and 705.8 ng L-1, respectively. Regarding the removal of compounds in the monitored WTPs, the clarification step demonstrated better removals for 4-nonylphenol, bisphenol-A, paracetamol, and sulfamethoxazole, whereas the disinfection step mainly removed the compounds 4-octylphenol and estrone. Margin of exposure (ME) assessment results indicated that only dexamethasone, ethinyl estradiol, diclofenac, estradiol, and estrone were classified as imminent risk or alert considering the 95th percentile concentration found in the samples of treated water.

Hydrogen production by Enterobacter sp. LBTM 2 using sugarcane bagasse hemicellulose hydrolysate and a synthetic substrate: understanding and controlling toxicity.

Sugars released by thermochemical pretreatment of lignocellulosic biomass are possible substrate for hydrogen production. However, the major drawback for bacterial fermentation is the toxicity of weak acids and furan derivatives normally present in such substrate. This study aimed to investigate the metabolism involved in hydrogen production by the isolate Enterobacter LBTM2 using 10, 20 and 30-fold diluted synthetic (SH) and sugarcane bagasse hemicellulose (SBH) hydrolysates. In addition, the effects of acetic acid, formic acid and furfural on the bacterial metabolism, as well as detoxification of SBH with activated carbon and molecularly imprinted polymers on the hydrogen production were assessed. The results showed the best hydrogen yield was 0.46 mmol H2/mmol sugar for 20-times diluted SH, which was 2.3-times higher than obtained in SBH experiments. Bacterial growth and hydrogen production were negatively affected by 0.8 g/L of acetic acid when added alone, but were totally inhibited when formic acid (0.4 g/L) and furfural (0.3 g/L) were also supplied. However the maximum hydrogen production of SBH20 has duplicated when 3% of powdered activated carbon was added to the SBH experiment. The results presented herein can be helpful in understanding the bottlenecks in biohydrogen production and could contribute towards development of lignocellulosic biorefinery.

Occurrence and removal of drugs and endocrine disruptors in the Bolonha Water Treatment Plant in Belém/PA (Brazil).

This study aimed to investigate the occurrence of drugs and endocrine disrupters in water supplies and in water for human consumption. Twelve sampling campaigns were carried out during the rainy and dry season at four sampling points in the Bolonha Complex, in the city of Belém, northern region of Brazil: Bolonha reservoir (catchment) and Water Treatment Plant (WTP) Bolonha (filtered water chamber, treated water tank, and washing water from the filters). The determination of the compounds was performed by solid phase extraction followed by gas and liquid chromatography coupled to mass spectrometry. The results confirmed the anthropic influence that the reservoir and WTP-Bolonha have been suffering, as consequence of the discharge of domestic sewage in natura. Among 25 microcontaminants analyzed, 12 were quantified in raw water and 10 in treated water. The antiallergic Loratadine (LRT) was the contaminant that occurred most frequently in all sample points, having been poorly removed (median 12%) in the conventional treatment used. Losartana (LST), 4-octylphenol (4-OP), and Bisphenol A (BPA) also occurred very frequently in raw water with concentrations ranging from 3.7 to 194 ng L-1. Although such contaminants occurred in treated water in concentrations varying from 4.0 to 135 ng L-1, the estimated margin of exposure ranged from 55 to 3333 times which indicates low risk of human exposure to such contaminants through ingestion of treated water.

Occurrence of contaminants of emerging concern in surface waters from Paraopeba River Basin in Brazil: seasonal changes and risk assessment.

This study describes the application of gas chromatography coupled to mass spectrometry (GC-MS) to evaluate the occurrence of 12 CECs-contaminants of emerging concern (bisphenol A, diclofenac, 17ß-estradiol, estriol, estrone, 17α-ethinylestradiol, gemfibrozil, ibuprofen, naproxen, 4-nonylphenol, 4-octylphenol, and acetaminophen) in surface waters from Paraopeba River Basin, Minas Gerais State, Brazil. The analytical procedure was validated and applied to 60 surface water samples collected across four sampling campaigns along the upper and middle watershed. Methods for CECs determination involved sample filtration, and solid-phase extraction (SPE) with subsequent derivatization of the target compounds prior to their analysis by GC-MS. The LOQ varied from 3.6 to 14.4 ng/L and extraction recoveries ranged from 46.1 to 107.1% for the lowest spiked concentration level (10 ng/L). The results showed a profile of spatial distribution of compounds, as well as the influence of rainfall. Ibuprofen (1683.9 ng/L), bisphenol (1587.7 ng/L), and naproxen (938.4 ng/L) occurred in higher concentrations during the rainy season, whereas during the dry season, the concentrations of bisphenol (1057.7 ng/L), estriol (991.0 ng/L), and estrone (978.4 ng/L) were highlighted. The risk assessment of human exposure shows that for most contaminants, the concentration is well below the estimated thresholds for chronic toxicity from water intake. However, estradiol and 17α-ethinylestradiol showed concentrations in the same order of magnitude as the guide values estimated for babies.

Can high rate algal ponds be used as post-treatment of UASB reactors to remove micropollutants?

The present study evaluated the removal capacity of a UASB-HRAP treatment system, combining anaerobic and microalgae-based, aerobic treatment, for eleven organic micropollutants present in raw sewage, including pharmaceuticals, estrogens and xenoestrogens. The UASB reactor and the HRAP were operated at a hydraulic retention time (HRT) of 7 h and 8 days, respectively. Influent and effluent samples from the UASB and HRAP were collected periodically. All the target compounds were detected in raw sewage, with an occurrence ranging from 70 to 100%. Removal rates in the UASB reactor were generally incomplete, ranging from no removal (-25.12% for the hormone EE2-ethinylestradiol) to 84.91% (E2 - estradiol). However, the overall performance of the UASB + HRAP system was highly efficient for the majority of the compounds, with removal rates ranging from 64.8% (ibuprofen) to 95% (estrone). Gemfibrozil and bisphenol A were the only exceptions, with overall removal rates of 39% and 43%, respectively. Hormones were the compounds with the highest removal rates in the system.

Anaerobic-Aerobic Combined System for the Biological Treatment of Azo Dye Solution using Residual Yeast.

This study aimed to investigate the treatment efficiency of a synthetic dye solution in an anaerobic-aerobic combined reactor system, using pretreated residual yeast as a nutrient source and redox mediator. The applicability of the residual yeast as a nutrient source was firstly evaluated in anaerobic batch tests. Subsequently, two continuous bench-scale treatment settings were studied: (1) an Upflow Anaerobic Sludge Blanket (UASB) reactor followed by an activated sludge system and, (2) a UASB reactor followed by a shallow polishing pond. The two system configurations were fed with a synthetic azo dye solution of Yellow Gold Remazol (50 mg/L) and pretreated residual yeast (350 mg/L). According to the results, the UASB/shallow polishing pond-combined reactor attained the best values of chemical oxygen demand (COD) (85%) and dye removal (23%).

Oxidação de fármacos por cloro e formação de subprodutos em amostras aquosas em escala de bancada / Pharmaceuticals oxidation by chlorine and byproducts formation in aqueous matrices in bench scale

RESUMO Fármacos e desreguladores endócrinos são encontrados em águas naturais brasileiras, incluindo alguns mananciais de abastecimento, também em função da baixa cobertura de coleta e tratamento de esgotos no Brasil. Nesse cenário, o presente trabalho intentou avaliar a remoção de três fármacos - sulfametoxazol (SMX), diclofenaco (DCF) e 17β-estradiol (E2) - em água destilada por meio da oxidação com cloro (hipoclorito de sódio), variando-se a dose de cloro e o tempo de contato em ensaios de batelada. As soluções cloradas foram analisadas, ainda, por cromatografia acoplada à espectrometria de massas para identificação de eventuais subprodutos de oxidação. Para tempo de contato de 10 min e dose de cloro de 1,5 mg.L-1, foi observada remoção média de 61% para DCF, 36% para E2 e 33% para SMX. Apenas para o DCF verificou-se diferença estatisticamente significativa (α=0,05) para dose de cloro de 3,0 mg.L-1. A oxidação seguiu modelo cinético de pseudossegunda ordem, com valores de k2 de 0,0168 L.µg.min-1 para SMX (para ambas doses testadas), de 0,0133 e 0,0798 L.µg.min-1 para DCF, e de 0,0326 e 0,0289 L.µg.min-1 para E2, para doses de cloro de 1,5 e 3,0 mg.L-1, respectivamente. Por fim, verificou-se que o aumento do tempo de contato favoreceu a oxidação dos fármacos, ainda que com a perspectiva de formação de subprodutos para SMX e E2.

ABSTRACT Pharmaceuticals and endocrine disrupting compounds are found in Brazilian natural waters, including some water sources for public supply, also due to the low coverage of sewage collection and treatment in Brazil. This study investigated the removal of three pharmaceutical compounds - sulfamethoxazole (SMX), diclofenac (DCF) and 17β-estradiol (E2) - from aqueous solutions by means of chlorine oxidation (sodium hypochlorite) by varying the dose of chlorine and contact time in batch tests. The chlorine solutions were examined by chromatography attached to the mass spectrometry in order to identify the oxidation by-products. For 10 min contact time, mean removal values of 61% were observed for DCF; 36% for E2; and 33% for SMX, when the chlorine dose was 1.5 mg L-1. Just for DCF there was a statistically significant difference (α=0.05) in the removal efficiency when increasing the chlorine dose to 3.0 mg.L-1. The oxidation followed the kinetic model of pseudo-second order, with k2 values of 0.0168 L.µg.min-1 for SMX (at both chlorine doses tested); 0.0133 and 0.0798 L.µg.min-1 to DCF; and 0.0326 and 0.0289 L.µg.min-1 to the E2 at chlorine doses of 1.5 and 3.0 mg L-1, respectively. Finally, it was verified that an increase of the contact time favored the oxidation of all pharmaceuticals tested, although with the perspective of by-products formation for SMX and E2.

Enhancement of anaerobic degradation of azo dye with riboflavin and nicotinamide adenine dinucleotide harvested by osmotic lysis of wasted fermentation yeasts.

The study presented here aims at identifying the source of redox mediators (riboflavin), electron carriers nicotinamide adenine dinucleotide (NAD) and carbon to perform decolorization of azo dye under anaerobic conditions after osmotic shock pretreatment of residual yeast from industrial fermentation. Pretreatment conditions were optimized by Doehlert experiment, varying NaCl concentration, temperature, yeast density and time. After the optimization, the riboflavin concentration in the residual yeast lysate (RYL) was 46% higher than the one present in commercial yeast extract. Moreover, similar NAD concentration was observed in both extracts. Subsequently, two decolorization experiments were performed, that is, a batch experiment (48 h) and a kinetic experiment (102 h). The results of the batch experiment showed that the use of the RYL produced by the optimized method increased decolorization rates and led to color removal efficiencies similar to those found when using the commercial extract (∼80%) and from 23% to 50% higher when compared to the control (without redox mediators). Kinetics analysis showed that methane production was also higher in the presence of yeast extract and RYL, and biogas was mostly generated after stabilization of color removal. In all kinetics experiments the azo dye degradation followed the pseudo-second-order model, which suggested that there was a concomitant adsorption/degradation of the dye on the biomass cell surface. Therefore, results showed the possibility of applying the pretreated residual yeast to improve color removal under anaerobic conditions, which is a sustainable process.

Comparison between two forms of granular activated carbon for the removal of pharmaceuticals from different waters.

The aim of this study was to evaluate the performance of two forms of basic granular activated carbon (GAC), mineral (pH = 10.5) and vegetal (pH = 9), for the removal of three pharmaceuticals, as sulphamethoxazole (SMX), diclofenac (DCF) and 17ß-estradiol (E2), from two different matrices: fortified distilled (2.4-3.0 mg L(-1) and pH from 5.5 to 6.5) and natural (∼1.0 mg L(-1) and pH from 7.1 to 7.2) water in a bench scale. The Rapid Small-Scale Column Test used to assess the ability of mineral and vegetal GAC on removal of such pharmaceuticals led to removal capacities varying from 14.9 to 23.5 mg g(-1) for E2, from 23.7 to 24.2 mg g(-1) for DCF and from 20.5 to 20.6 mg g(-1) for SMX. Removal efficiencies of 71%, 88% and 74% for DCF, SMX and E2, respectively, were obtained at breakthrough point when using mineral GAC, whereas for the vegetal GAC the figures were 76%, 77% and 65%, respectively. The carbon usage rate at the breakthrough point varied from 11.9 to 14.5 L g(-1) for mineral GAC and from 8.8 to 14.8 L g(-1) for vegetal GAC. Mineral CAG also exhibited the best performance when treating fortified natural water, since nearly complete removal was observed for all contaminants in the column operated for 22 h at a carbon usage rate of 2.9 L g(-1).

Photodegradation of bisphenol A in aqueous medium: monitoring and identification of by-products by liquid chromatography coupled to high-resolution mass spectrometry.

RATIONALE: Environmental bisphenol A (BPA) contamination is currently a matter of concern. This compound can disrupt the endocrine system by mimicking natural hormones and cause adverse effects on different organisms. In addition, it has been suggested that BPA can impair brain development, especially in fetuses and children. To efficiently remove BPA from contaminated water and wastewaters, several emerging technologies have been developed. Most are based on photodegradation. However, by-products resulting from the application of such methods have not been properly characterized. METHODS: The photodegradation of BPA was conducted using two different methods: photocatalysis (TiO2/UV-A and TiO2/UV-C systems) and direct photolysis (UV-A and UV-C radiation). The degradation process was continuously monitored to identify and observe the by-products formed under these conditions. Direct infusion electrospray ionization coupled to high-resolution mass spectrometry in negative ion mode [ESI(-)-HRMS] and liquid chromatography coupled to high-resolution mass spectrometry (HPLC/HRMS) were employed to monitor these by-products. RESULTS: The results revealed that the TiO2/UV-C system was the most efficient in causing both BPA depletion and mineralization of the organic matter in solution. Moreover, accurate mass data allowed for the assignment of molecular formulae for seven by-products, many of them unprecedented, formed under these conditions. Thus, a route for the photodegradation of BPA in aqueous medium could be proposed based on these results. Finally, additional tests revealed that the by-products showed a higher toxicity against Artemia salina than the primary precursor. CONCLUSIONS: All of these findings indicate that the identification of by-products arising from oxidative treatments is of primary importance because such compounds can be more hazardous than their precursors.

Behaviour of pharmaceuticals and endocrine disrupting chemicals in simplified sewage treatment systems.

This work assessed the behaviour of nine pharmaceuticals and/or endocrine disrupting chemicals (EDCs) in demo-scale upflow anaerobic sludge blanket reactors (UASB reactors) coupled to distinct simplified post-treatment units (submerged bed, polishing ponds, and trickling filters) fed on raw sewage taken from a municipality in Brazil. The dissolved concentration of the studied micropollutants in the raw and treated sewage was obtained using solid phase extraction (SPE) followed by analysis in a liquid chromatography system coupled to a hybrid high resolution mass spectrometer consisting of an ion-trap and time of flight (LC-MS-IT-TOF). The UASB reactors demonstrated that they were not appropriate for efficiently removing the assessed compounds from the sewage. Furthermore, this study demonstrated that the hydraulic retention time (HRT) was an important parameter for the removal of the hydrophilic and less biodegradable compounds, such as trimethoprim and sulfamethoxazole. The post-treatment units substantially increased the removal of most target micropollutants present in the anaerobic effluents, with a greater removal of micropollutants in simplified systems that require a large construction area, such as the submerged bed and polishing ponds, probably because of the higher HRT employed. Alternatively, compact post-treatment systems, such as trickling filters, tended to be less effective at removing most of the micropollutants studied, and the type of packing proved to be crucial for determining the fate of such compounds using trickling filters.

Implications of volatile fatty acid profile on the metabolic pathway during continuous sulfate reduction.

Volatile fatty acid (VFA) profile is an important parameter in anaerobic reactors because it enables the assessment of metabolic pathways. Volatile fatty acids were monitored during sulfate reduction in a UASB (upflow anaerobic sludge blanket) reactor treating 2g/L sulfate concentration and with the organic loading increasing from 3.5 kg COD/m(3)d to 5.9 kg COD/m(3)d, for a 1-day residence time. In the absence of recirculation, the best outcome (65% reduction) was noticed with the lowest organic loading (3.55 kg/m(3)d). When recirculation was applied, sulfate reduction yields increased to 89%, corresponding to a sulfate removal rate of 1.94 kg SO(4)(2-)/m(3)d. The reactor performance was discussed in relation to microbial diversity and metabolic pathways. At high organic loading, two metabolic pathways account for lactate degradation: (i) lactate is oxidized to acetate and carbon dioxide by the incomplete-oxidizer SRB (sulfate-reducing bacteria) Desulfomonas, Desulfovibrio, Desulfolobus, Desulfobulbus and Desulfotomaculum spp.; (ii) lactate is converted to acetate by fermenting bacteria such as Clostridium sp. High propionate concentrations imply that there are low sulfate reduction efficiencies.

Caracterização e tratabilidade biológica dos efluentes líquidos gerados em cabines de pintura de uma indústria moveleira / Characterization and treatability of wastewater from a dying hood of a furniture industry

O objetivo deste trabalho foi caracterizar os efluentes gerados em cabines de pintura de uma indústria moveleira e avaliar a eficiência de sistemas biológicos (anaeróbio e aeróbio) para o seu tratamento. O efluente industrial apresentou elevado teor de matéria orgânica (DQO total de 634 a 2.790 mg.L-1; DBO5 total de 360 a 972 mg.L-1) e baixos teores de macronutrientes (NTK de 1,9 mg.L-1 e Ptotal de 0,5 mg.L-) e metais tóxicos. Os ensaios de tratabilidade em reator UASB (~25ºC e tempo de detenção hidráulica - TDH = 10 horas), indicaram uma eficiência máxima de remoção de matéria orgânica de 90 por cento na composição volumétrica 70:30 (efluente industrial:esgoto sanitário). A alimentação do reator UASB só com efluente industrial resultou em acúmulo de ácidos graxos voláteis e inibição microbiana, mas o uso de pós-tratamento aeróbio (TDH = 96h) garantiu elevada eficiência global (~88 por cento) de remoção de matéria orgânica.

The main objective of this work was to characterize the wastewater from the dying hood of a woven furniture industry, and to assess the efficiency of biological processes (anaerobic and aerobic) for its treatment. The physical-chemical characterization of the industrial wastewater showed a high organic matter content (total COD from 634 to 2,790 mg.L-1; total BOD5 from 360 to 972 mg.L-1), low content of macronutrients (NTK of 1.9 mg.L-1 and P of 0.5 mg.L-1) and toxic metals. The anaerobic degradation tests in a bench-scale UASB reactor (25ºC and hydraulic retention time - HRT = 10 hours) showed that a maximum removal efficiency of 90 percent was obtained when the reactor was fed with 30 percent raw sewage and 70 percent industrial wastewater. The feeding of UASB reactor with only industrial wastewater resulted in volatile fatty acids accumulation and microbial inhibition; however, the use of aerobic post-treatment (HRT = 96 hours) granted a high (~88 percent) organic matter removal efficiency.

Aplicação de princípios de bioenergética no cálculo da estequiometria de reações biológicas em processos de tratamento de águas residuárias / Application of bioenergetic principles to the stoichiometry of biological reactions in wastewater treatment processes

O tratamento biológico de águas residuárias é realizado por microrganismos que utilizam determinado substrato para obtenção de energia e crescimento celular através de reações de oxidação-redução e fermentação. Esses mecanismos podem ser expressos por meio de reações estequiométricas desenvolvidas a partir de princípios da termodinâmica. As reações são dependentes dos compostos doadores e aceptores de elétrons. As equações balanceadas resultantes permitem estimar as necessidades de nutrientes, a variação de pH/alcalinidade, a produção de biomassa e gases e o coeficiente de produção celular associados aos sistemas biológicos de tratamento. Esta nota técnica descreveu a metodologia para cálculo estequiométrico de reações bioquímicas usando princípios de bioenergética, apresentando exemplos para diferentes substratos e aceptores de elétrons.

Biological wastewater treatment is performed by microorganisms by means of oxidation-reduction and fermentation reactions that release energy for growth and maintenance. These processes can be represented by stoichiometric reactions developed based on thermodynamic principles. Reactions are dependent on the compounds used as electron donor and acceptor. The overall stoichiometric reactions allow estimations of nutrient requirements, alkalinity/pH changes, biomass and gas production, and yield coefficient. This article described a methodology for stoichiometry calculations using bioenergetic principles, presenting examples with different substrates and electron acceptors.

Influence of incubation conditions on the specific methanogenic activity test.

The main objective of this work was to evaluate the influence of incubating conditions on the specific methanogenic activity (SMA) test in order to harmonize the test protocol. For this serum bottles were incubated with anaerobic sludge (from UASB reactor treating domestic sewage) in factorial planned experiments which assessed the influence of the temperature, substrate concentration, food/microorganism (F/M) ratio, presence of yeast extract in the medium, as well as type of carbon and nutrient solution. The results showed that the tested methane measuring methods (volumetric with biogas characterization, volumetric with gas wash in alkaline solution, and manometric by using the OxiTop system) presented a similar performance. The maintenance of a small gaseous phase volume (e.g. 10% of the total volume) resulted in higher SMA values; and the ideal substrate concentration for the SMA test ranged from 0.5 to 3.0 g COD/l since higher acetate concentration caused sludge inhibition. The suggested temperature for the test is 35 degrees C and the best F/M ratio varied from 0.125 to 0.750 g COD/g VS, and this seemed to be the most influent parameter for the SMA test. Finally tests performed with nutrient solution complemented by yeast extract resulted in the highest SMA values.

Occurrence of endocrine disrupting compounds in water sources of Belo Horizonte Metropolitan Area, Brazil.

Endocrine disrupting compounds (EDCs) have attracted the attention of the scientific community because of the effects of EDCs on aquatic fauna and the potential threat they pose to human health. There are a handful of papers on the monitoring of EDCs in Brazilian surface waters, hence this research was aimed at assessing, by using liquid chromatography coupled to mass spectrometry (LC-MS), the presence of 17 beta-estradiol, 17 alpha-ethynylestradiol and 4-nonylphenol in surface waters used for supplying the Belo Horizonte Metropolitan Area, Minas Gerais state, Brazil. The one-year monitoring period of three water sources showed that 4-nonylphenol was detected in all samples in a concentration range of 44 to 1918 ng L(-1), whilst the natural and synthetic estradiols were hardly detected (only in approximately 15% of samples) and always in low concentrations (2 to 54 ng L(-1)). Samples of partially treated water, collected in three water treatment plants before the chlorination step, showed that the steps of prechlorination, flocculation-sedimentation and sand filtration did not efficiently remove the EDCs studied.

Quantification of the inert chemical oxygen demand of raw wastewater and evaluation of soluble microbial product production in demo-scale upflow anaerobic sludge blanket reactors under different operational conditions.

This paper investigates the production of soluble microbial products (SMPs) in demonstration-scale upflow anaerobic sludge blanket reactors operated under different conditions and fed with raw wastewater. The results showed that 9.2 +/- 1.3% of the influent soluble chemical oxygen demand (COD) could be considered inert to anaerobic treatment and that the amount of COD produced by biomass varied from 30 to 70 mg x L(-1), accounting for 45 to 63% of the soluble effluent COD. The accumulation of SMP appeared to be dependent on the hydraulic retention time (HRT) applied to the reactors, with a larger accumulation of SMP observed at the lowest HRT (5 hours); this may have been due to stress conditions caused by high upflow velocity (1.1 m x h(-1)). In terms of residual COD characterization, ultrafiltration results showed that higher amounts of high molecular weight compounds were found when HRT was the lowest (5 hours), and that the molecular weight distribution depended on the operational condition of the reactors. Biodegradability tests showed that the low and high molecular weight SMPs were only partially degraded anaerobically (10 to 60%) and that the high molecular weight SMPs were difficult to degrade aerobically.

Characterization of landfill leachates by molecular size distribution, biodegradability, and inert chemical oxygen demand.

This work presents results from a detailed characterization of landfill leachates of different ages from a landfill in a major Brazilian city. This characterization consists of determining the molecular size distribution and the inert chemical oxygen demand (COD) and the biodegradability of both aerobic and anaerobic processes. Results show that leachate with a high COD concentration leachate has low biodegradability. A significant fraction of the COD is not characterized as protein, carbohydrate, or lipids, which reinforces the hypothesis that the remaining fraction was present in all leachate fractions (less than 1 kDa; between 1 and 10 kDa; between 10 and 100 kDa; and greater than 100 kDa) and is refractory. These results suggest that leachates with such characteristics require treatment systems that use physical-chemical processes as a pre- or post-treatment step to biological processes.

Caracterização e biodegradabilidade aeróbia e anaeróbia dos esgotos produzidos em campus universitário / Characterization and biodegradability of wastewater produced in university campus

O presente trabalho caracterizou e avaliou a tratabilidade dos efluentes líquidos produzidos no campus da Universidade Federal de Ouro Preto. Os parâmetros físico-químicos mostraram que o efluente do campus possui uma característica típica a dos esgotos domésticos, com valores médios de DBO5 total, DQO total, NTK e P total de 300 mg.L-1, 670 mg.L-1, 56 mg.L-1 e 6 mg.L-1 respectivamente. Dos metais monitorados somente o Fe (0,847 mg/L), Al (0,355 mg/L) e Zn (0,389 mg/L) estavam presentes em maiores concentrações, mais ainda assim, tais concentrações eram inferiores aos va-lores considerados tóxicos para microrganismos. Os testes de biodegradabilidade mostraram que, a despeito da potencial presença de compostos orgânicos tóxicos, o efluente final pode ser biodegradado aerobiamente (97 por cento de eficiência, K1app = 1,73 d-1) e anaerobiamente (50 por cento de eficiência, AME = 0,0579 gDQO CH4/gSSV.d).

The aim of this study was to characterize and evaluate the tratability of wastewater produced in the campus of the Federal University of Ouro Preto (UFOP). The physical-chemical parameters showed the wastewater from the campus had characteristics of typical domestic wastewater, with average values of total BOD, total COD, Kjeldahl Nitrogen and total phosphorus of 300 mg.L-1, 670 mg.L-1, 56 mg.L-1 e 6 mg.L-1 respectively. Only the metals Fe (0,847 mg/L), Al (0,355 mg/L) and Zn (0,389 mg/L) were present in higher concentration, nonetheless, such concentrations were below the thresholds limits for microbial toxicity. The biodegradability tests showed that despite the potential presence of toxic organic compounds, the wastewater could be degraded aerobically (97 percent efficiency, K1app = 1,73 d-1) and anaerobically (50 percent efficiency, AME = 0,0579 gDQO CH4/gSSV.d).

Metodologias para determinação da atividade metanogênica específica (AME) em lodos anaeróbios / Methodologies for determining the specific methanogenic activity (SMA) in anaerobic sludges

Esse artigo apresenta uma revisão sobre os diferentes protocolos para a determinação da atividade metanogênica específica (AME) de lodos anaeróbios. Os protocolos propostos se diferem tanto em relação aos procedimentos adotados para a incubação do lodo, quanto ao método utilizado para quantificação do metano produzido durante o teste. São discutidos os princípios dos métodos manométricos e volumétricos, e descritos brevemente os protocolos de incubação do lodo, de medição do metano e o procedimento para cálculo da AME obtida pelos métodos mais utilizados pela comunidade científica nacional.

This paper presents a review on the different methodologies to determine the specific methanogenic activity (SMA) of anaerobic sludges. The protocols available in the literature differ not only regarding the procedures adopted to incubate the sludge, but also in relation to the method utilized to quantify the methane produced during the test. This paper discusses the principles of manometric and volumetric methods, and briefly describes the protocols mostly used by the Brazilian research community for sludge incubation, methane measurement and calculation of SMA.