Baffled primary facultative ponds with inlets and outlets set at different levels treating domestic wastewater in northeast Brazil.

This study evaluates the performance of four 2.3 m deep pilot-scale, independently loaded, primary facultative ponds treating predominantly domestic sewage in northeast Brazil. The ponds contained longitudinal baffles giving different length to width ratios from 3.55 to 32.4. The ponds had mean hydraulic retention times of ~15 days, and mean surface organic loadings of 330 kg BOD(5).ha.d(-1) during the first experimental phase and 375 kg BOD(5).ha.d(-1) in the second. The vertical inlets and outlets pipes were positioned at 1.8 m and 5 cm respectively below the pond surface in the first phase and at 50 cm and 1.8 m respectively in the second. All the ponds functioned as efficient primary facultative ponds but statistical analysis demonstrated no differences in effluent quality for most of the parameters measured for the various configurations of baffles and inlet and outlet depths. All behaved similarly to the unbaffled pond. The only exceptions were suspended solids and chlorophyll a concentrations which tended to be lower for all combinations of baffles with the outlets set 1.8 m below the surface. This study suggested that the longitudinal baffling of primary facultative ponds when using vertical inlets and outlets may well not significantly improve pond performance.

The removal of ammonia from sanitary landfill leachate using a series of shallow waste stabilization ponds.

This study evaluated the efficiency of a shallow (0.5 m deep) waste stabilization pond series to remove high concentrations of ammonia from sanitary landfill leachate. The pond system was located at EXTRABES, Campina Grande, Paraiba, Northeast Brazil. The pond series was fed with sanitary landfill leachate transported by road tanker to the experimental site from the sanitary landfill of the City of Joao Pessoa, Paraiba. The ammoniacal-N surface loading on the first pond of the series was equivalent to 364 kg ha(-1) d(-1) and the COD surface loading equivalent to 3,690 kg ha(-1) d(-1). The maximum mean ammonia removal efficiency was 99.5% achieved by the third pond in the series which had an effluent concentration of 5.3 mg L(-1) ammoniacal-N for an accumulative HRT of 39.5 days. The removal process was mainly attributed to ammonia volatilization (stripping) from the pond surfaces as a result of high surface pH values and water temperatures of 22-26°C. Shallow pond systems would appear to be a promising technology for stripping ammonia from landfill leachate under tropical conditions.

Performance of constructed wetland systems treating anerobic effluents.

The purpose of this present paper is to verify the performance of three wetland systems operated with effluents from a UASB reactor, with respect nutrient removal (nitrogen and phosphorus), pathogenic organisms and remaining carbonaceous material, monitored over a three-year period. The experiment was carried out and monitored at PROSAB (Programa de Saneamento Básico) in Campina Grande, Paraíba. The removal efficiency of the carbonaceous material expressed in DQO ranged from 70 to 86%, but concerning the total suspended solids, the efficiency ranged from 50 to 71%. The removal efficiency in terms of nitrogen and phosphorus of both vegetated systems was about 65.5 to 86%, respectively, during the first year of operation. Under the operational conditions of the experiment, the removal of phosphorus in a wetland system containing washed sand as the substratum decreased, as its operation period increased. The vegetated wetland has been the most efficient in removing faecal coliforms (roughly 4 log units) as compared to the non-vegetated one (about 3 log units), when both were operated with the same hydraulic load (2.3 cm. per day). Thus, the effluent produced over the three-year period ranged from 800 to 1,800 UFC/100 mL in the analyzed samples.

Post-treatment of anaerobic effluents in constructed wetland systems.

This papers describes the behaviour of wetlands as a post-treatment unit for anaerobically treated sewage for the removal of organic matter, suspended solids, nutrients (nitrogen and phosphorus) and faecal coliforms. Raw sewage was treated in a UASB reactor with a retention time of 5 h and the effluent was used in four units of wetlands with coarse sand as the medium and operated with different hydraulic loads. Three of the units had emerging macrophytes (Juncus sp), whereas the fourth one was operated as a control unit without plants. During the 12 months of operation, the organic material removal efficiency (measured as COD) was in the range of 79 to 85%, whereas suspended solids removal varied from 48 to 71%. Faecal coliform removal was very high (99.99%); phosphorus was also efficiently removed (average efficiency of 90% for the lowest hydraulic load), but nitrogen removal was only partial (45 to 70% for ammonia and 47 to 70% for TKN). The experimental results clearly show the technical feasibility of using wetlands for treatment of municipal sewage after a pre-treatment in the UASB reactor.

Stereotactic subthalamic nucleus lesioning for the treatment of Parkinson's disease.

This study was performed to evaluate the effectiveness and safety of unilateral STN lesioning in 23 patients with PD. L-Dopa intake and dyskinesia, Hoehn & Yahr, Schwab & England, and UPDRS motor scores were recorded pre- and postoperatively. Stereotactic MRI and CT and macrostimulation were used to establish target coordinates. A single RF lesion was performed. All patients underwent postoperative MRI. Contralateral tremor arrest and decrease of rigidity and bradykinesia should be regarded as hallmarks to STN stimulation. All recorded parameters were significantly improved after a mean follow-up of 13.5 months. Patients with STN lateral territory lesioning (alpha <0.05), younger than 61 years and with a duration of the disease between 6 and 9 years (alpha >0.05) did better than the others. The recurrence rate was 10%. Two patients developed dyskinesias which were completely resolved by a Vim/VOp lesion. Other significant complications were rare. The authors conclude that unilateral STN lesioning is a safe and very effective procedure to treat PD.

[Intraoperative echography in biliary tract surgery. A comparative study of intraoperative echography/cholangiography in the detection of calculi in the common bile duct]. / Ecografia per-operatória em cirurgia das vias biliares. Estudo comparativo ecografia/colangiografia per-operatória na detecção de cálculos na via biliar principal.

We report 3 years of experience with operative ultrasonography on 200 patients who underwent cholecystectomy for biliary lithiasis. Intraoperative ultrasonography and intraoperative cholangiography were performed on all of these patients and compared with the operative findings. The diagnostic accuracy of sonography was 98% and that of cholangiography 96% in the whole patient group. The predictive value of a positive ultrasonography was 92.5% while that of a positive cholangiogram was lower at 81.5%. In 32 patients who underwent surgical exploration of the common duct the use of these two intraoperative screening tests together led to a positive common duct exploration in 75% of the patients. Overall morbidity in this series was 4.8% against 12.8% (common duct exploration) and retained stones following duct exploration were present in 1 patient in intra-hepatic situation. The overall mortality rate of the entire patient group was 0%. Operative ultrasonography of the biliary tract as a screening procedure is a reliable method, a possible substitute for operative cholangiography, but perhaps in reality both methods are complementary.

[Rheumatic fever--exacerbation or decline? Analysis of patients admitted to a medical service within a period of 20 years]. / Febre reumática--recrudescência ou declínio? Análise dos internamentos num serviço de medicina com intervalo de 20 anos.

The authors revised 116 clinical files of patients admitted to a Medicine ward with Rheumatic Fever in the years 1959-63 and 1979-83, in order to detect a possible recrudescence of the disease. The following parameters were analysed: age, sex, length of hospital stay, clinical manifestations, ancillary exams, therapeutics and evolution. It was found an impressive decline in the incidence of the disease (90 cases vs 26) and also a very significant decrease of the period of hospitalization in the recent group of patients (p less than 0.0005); Carditis and relapses of Rheumatic Fever were more frequent in the old group of patients.