Otimização e validação da extração sólido-líquido e purificação em baixa temperatura de HPAs em lodo de esgoto

In this study, a method of solid-liquid extraction and purification at low temperature (SLE-PLT) to determine 16 polycyclic aromatic hydrocarbons (PAHs) in sewage sludge was optimized and validated. The analyses were performed by HPLC-UV. The extraction phase, homogenization procedure, influence of pH, ionic strength and clean-up of the extracts were optimized. Recoveries were higher than 63.4% for 11 PAHs. The correlation coefficients were greater than 0.99 and limits of detection and quantitation were less than 0.060 and 0.15 µg g-1, respectively. These values were lower than the maximum residue limits of PAHs established by European legislation. SLE-PLT proved a more practical, economical method with fewer steps compared to Soxhlet extraction (reference method) for PAHs in sewage sludge.

Avaliação do desempenho de dois sistemas modulares no tratamento anaeróbio de esgotos em comunidades rurais

Este trabalho apresenta uma alternativa de baixo custo e fácil instalação para o tratamento de esgotos de pequenas comunidades. O experimento foi desenvolvido no Campo Experimental da Faculdade de Engenharia Agrícola (FEAGRI/UNICAMP). O volume total de esgoto gerado na FEAGRI é de cerca de 20 m³ dia-1, sendo metade desse tratado pelos sistemas modulares. O sistema da linha (A) é constituído por um reator UASB (Upflow Anaerobic Sludge Blanket), seguido de dois filtros anaeróbios e o outro sistema, linha (B), é constituído por um reator tipo RAC (Reator Anaeróbio Compartimentado), seguido de dois filtros anaeróbios (FA). Os sistemas foram operados de dezembro de 2002 a fevereiro de 2004, totalizando 30 coletas de amostras. Observou-se que, de maneira geral, o desempenho dos sistemas foram similares e com resultados satisfatórios. As eficiências médias de remoção de Sólidos Sedimentáveis, Sólidos Suspensos Totais e DQO, observadas no sistema modular da Linha (A), foram, respectivamente, 99,58%; 94,33% e 67,30%. O sistema modular da Linha (B) apresentou remoção de 99,49%; 93,34% e 70,45% para os mesmos parâmetros. Os sistemas modulares mostraram-se adequados e viáveis para promover o tratamento sanitário do esgoto produzido em pequenas comunidades.

Performance of UASB reactors in two stages under different HRT and OLR treating residual waters of swine farming

In this study it was evaluated the effects of hydraulic retention time (HRT) and Organic Loading Rate (OLR) on the performance of UASB (Upflow Anaerobic Sludge Blanket) reactors in two stages treating residual waters of swine farming. The system consisted of two UASB reactors in pilot scale, installed in series, with volumes of 908 and 188 L, for the first and second stages (R1 and R2), respectively. The HRT applied in the system of anaerobic treatment in two stages (R1 + R2) was of 19.3, 29.0 and 57.9 h. The OLR applied in the R1 ranged from 5.5 to 40.1 kg CODtotal (m³ d)-1. The average removal efficiencies of chemical oxygen demand (COD) and total suspended solids (TSS) ranged, respectively, from 66.3 to 88.2% and 62.5 to 89.3% in the R1, and from 85.5 to 95.5% and 76.4 to 96.1% in the system (R1 + R2). The volumetric production of methane in the system (R1 + R2) ranged from 0.295 to 0.721 m³CH4 (m³ reactor d)-1. It was found that the OLR applied were not limiting to obtain high efficiencies of CODtotal and TSS removal and methane production. The inclusion of the UASB reactor in the second stage contributed to increase the efficiencies of CODtotal and TSS removal, especially, when the treatment system was submitted to the lowest HRT and the highest OLR.

Nutrient loss in composting of agroindustrial residues

The management of composting may influence the characteristics of the produced compounds. The experiment used three frequencies of plowing, combined with the conditions: with and without coverage of the composting patio, with and without the use of commercial inoculant, resulting in 12 furrows, installed on the Experimental Center of Agricultural Engineering (NEEA), of the STATE UNIVERSITY OF WEST PARANÁ (UNIOESTE), Campus of Cascavel city - state of Paraná (PR), in Brazil. The waste and quantities used in kg were: corn cob (7.5); hatchery residue (5); floater sludge (31); ash (1); wheat cleaning residue (120); wheat pre-cleaning residue (120); corn peel (7.5); solid fraction of wash trucks used to transport chickens (2); solid fraction of pig manure (1) and coal (5), totaling 300kg of natural matter. The aim of this study was to evaluate the influence of plowings, patio coverage and inoculation in losses of N, P, K, Ca, Mg, Na, Cu, Zn, Mn, Fe. The furrows plowed three times a week in the first month showed significant higher losses of N (p<0.05). The coverage of the composting patio influenced significantly the losses of N, K, Mg and Na (p<0.05). The produced compounds had a high agronomic value in relation to macro and micronutrients. It is recommended the use of patio coverage and plowing twice a week in the first month and once a week in the subsequent months for a compound with higher concentrations of nutrients.

Anaerobic-aerobic treatment of swine wastewater in uasb and batch reactors in series

In this work it was evaluated the performance of two systems of swine wastewater treatment consisting of two-stage upflow anaerobic sludge blanket (UASB) reactors, with and without post-treatment in sequencing batch reactor (SBR), fed continuously, with aerobic phase. The UASB reactors in the first stage had 908 L in the sets I and II, and in the second stage 350 and 188 L, respectively. In the set II the post-treatment was performed in a SBR of 3,000 L. The hydraulic detention times in the anaerobic treatment systems were 100, 75 and 58 h in the set I; 87, 65 and 51 h in the set II; and 240 and 180 h in the SBR. The volumetric organic load applied in the first stage UASB reactors ranged from 6.9 to 12.6 g total COD (L d)-1 in the set I and 7.5 to 9.8 g total COD (L d)-1 in the set II. The average removal efficiencies of total COD, total phosphorus (Ptotal), and Kjeldahl and organic nitrogen (KN and Norg) in the anaerobic treatment systems were similar and reached maximum values of 97%, 64%, 68%, and 98%. In the SBR, the removal efficiencies of total COD and thermotolerant coliforms were up to 62 and 92% resulting, respectively, in effluent concentrations of 135 mg L-1 and 2x10(4)MPN (100 mL)-1. For Ptotal, total nitrogen (TN) and Norg, the average removal efficiencies in the SBR were up to 58, 25 and 73%, respectively.

COD, TSS, nutrients and coliforms removals in UASB reactors in two stages treating swine wastewater

The performance of two upflow anaerobic sludge blanket (UASB) reactors was evaluated in pilot scale (908 and 188 L), installed in series (R1 and R2), fed with swine wastewater with TSS around 5 and 13 g L-1. The UASB reactors were submitted to HDT of 36 and 18 h with VOL of 5.5 to 34.4 g COD (L d)-1 in the R1 and HDT of 7.5 e 3.7 h with VOL from 5.1 to 45.2 g COD (L d)-1 in the R2. The average removal efficiencies of COD ranged from 55 to 85% in the R1 and from 43 to 57% in the R2, resulting in values from 82 to 93% in the UASB reactors in two stage. Methane concentrations in the biogas were 69 to 74% with specific production from 0.05 to 0.27 L CH4 (g removedCOD)-1 in the R1 and of 0.10 to 0.12 L CH4 (g removedCOD)-1 in the R2. The average removal efficiencies were 61 to 75% for totalP, 39 to 69% for KN, 82 to 93% for orgN and 20 to 94% for Fe, Zn, Cu and Mn. The amN concentration were not reduced indicating the need to post-treatment for effluent disposal into water bodies. There were reductions of total coliforms from 99.8123 to 99.9989% and of thermotolerant coliforms from 99.9725 to 99.9999%. The conditions imposed to the UASB reactors in two stage provided high conversions of removedCOD into methane (up to 77%) and reductions of organic an inorganic pollution loads from swine wastewater.

Start-up of anaerobic reactors for slaughterhouse wastewater treatment

This study aimed to evaluate the start-up of a horizontal anaerobic fixed bed reactor (HAFBR) followed by an upflow anaerobic sludge blanket (UASB) for the slaughterhouse wastewater treatment. HAFBR was filled with bamboo rings and had 1.2 m in length, 0.10 m in diameter and volume of 7.5 L. The UASB had the volume of 15 L. The HAFBR and UASB operated at organic loading rate and hydraulic retention time average of 8.46 and 3.77 kg m-3 d-1 of COD and 0.53 and 0.98 days, respectively. During 150 days of monitoring system it was found pH 6.8, relatively high values of bicarbonate alkalinity (> 1000 mg L-1) and reduced values of volatile acids (70 to 150 mg L-1), which afforded average removal efficiencies of COD total and total suspended solids of the order of 31 and 23% in HAFBR and 79% and 63% in UASB. It can be concluded that the generation and consumption of bicarbonate alkalinity and total volatile acids, thereby maintaining the pH during the study indicated stable operation of the reactors. The COD removal in the reactors was satisfactory especially when it considers that the assessment was conducted in a period of adaptation of organisms to the effluent and also the high organic load applied during this period.

Effect of cycle time and airflow in biological nitrogen removal from poultry slaughterhouse wastewater using sequencing batch reactor

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.

Vólvulo da vesícula biliar tratado por colecistectomia laparoscópica

Our objective is to report a case of gallbladder torsion treated by laparoscopic cholecystectomy. A 87 year old patient presented with intense right upper quadrant pain, anorexia, nausea and vomiting. Murphy's sign was present at physical examination. Hemogram showed 9.200 leukocytes/mm³, with six bands. Ultrassonography showed a distended gallbladder, perivesicular fluid collection, wall edema, and sludge with stones inside. At laparoscopic cholecystectomy, there was a complete gallbladder torsion with areas of necrosis. There was no postoperative complication. Pathologic examination confirmed the diagnosis of acute calculous cholecystitis with areas of necrosis.