José Roberto Campos

Pectus excavatum: evaluation of Nuss technique by objective methods

Pectus excavatum (PEX) is the most frequent congenital deformity of the anterior chest wall. Few studies have classified the degree of anatomical distortion in an objective manner. Our objective was to present two new clinical and original methods for evaluation of PEX deformity developed in our service (chest cyrtometry and anthropometric index) that are simple and easily applicable in the office. Twenty patients with PEX (submitted to the technique of Nuss) and forty normal chest patients were studied: all patients were evaluated by the same objective methods. Our results suggest that the objective clinical methods are more sensitive or precise than the radiological ones by measuring the deformity in a direct manner external to the chest.

Aplicabilidade das técnicas de determinação de tamanho de partículas em sistemas de tratamento de água e esgoto sanitário

The improvement of water and wastewater treatment systems has been limited by the little knowledge of phenomena that take place inside the units and by the use of non-specific parameters (e.g. BOD, COD etc.) in monitoring and controlling of treatment processes and operations. On the other hand, phenomena such as mass transfer, adsorption, diffusion and biochemical reaction are all influenced by particle size distribution, in a way that the use of particle size measurement can aid in choosing and improving treatment technology and in adoption of appropriate operational procedures. In this article, the main particle size measurement techniques are presented, as well as the potential benefits of its use in research and in the improvement of design and operational routines for water and wastewater treatment systems.

Determinação da quantidade de areia no esgoto sanitário: metodologia e estudo de caso

Although degritters have been largely used, for more than a century, as preliminary treatment units of wastewater treatment plants (WWTP), their removal efficiency is yet poorly known due to the lack of standardized analytical methods to determine wastewater grit concentration. This paper brings up this subject and presents an original method to determine wastewater grit concentration based on use of well-known procedures, such as: Imhoff cone sedimentation, hydrogen peroxide oxidation, sequential rinse, calcination and analytical balance weighing. The application of the developed method demonstrated that grit concentration in the influent of WWTP Jardim das Flores varies significantly, with peak concentration of about 200 mg/l, and that the mean grit concentration seems to be among 20 mg/l and 73 mg/l.

Dissolved-air flotation associated with an anaerobic reactor, as applied to sewage treatment

This paper presents the results of a study performed with a pilot sewage treatment plant consisting of an aerobic reactor followed by a flotation unit. To coagulate the anaerobic effluent, different ferric chloride dosages were applied by adopting two approaches: applying constant dosages during the essay and varying the dosages according to the anaerobic effluent turbidity. To obtain more than 95% TSS, 90% COD and 70% phosphorous removals a critical chemical ratio ranging 0.012 - 0.013 (in terms of Fe/Turbidity ratio) was required. When aiming higher phosphorous removal (above 95%) the required Fe/Turbidity ratio range rose to 0.016-0.018.

O emprego da análise de imagem na determinação da distribuição de tamanho de partículas da areia presente no esgoto sanitário

E consensual, no meio tecnico, que unidades de desarenacao devem reter particulas discretas de elevada velocidade relativa de sedimentacao (por exemplo: areia, silte, cinzas, semente de frutas etc); e que desarenadores capazes de remover graos de areia de tamanho maior ou igual a 0,2 mm removem a maior parte dos materiais que ocasionam problemas operacionais em estacoes de tratamento de esgoto (ETE). Entretanto, nao existe concordância acerca da forma de se determinar a concentracao ou a distribuicao granulometrica de tais materiais no esgoto sanitario. O presente artigo apresenta um metodo para determinar a distribuicao granulometrica da areia presente no esgoto sanitario, o qual se baseia no emprego de tecnicas de analise de imagens digitais. A aplicacao do metodo proposto demonstrou que, em media, 84% da massa de areia carreada pelo esgoto sanitario afluente da ETE Jardim das Flores (Rio Claro, SP) era composta por particulas maiores ou iguais a 0,2 mm.