RESUMO
The aim of this research was to assess the hydraulic behaviour of three intermittently-fed vertical flow wetland units operated in parallel, designed for the treatment of raw wastewater generated in the city of Belo Horizonte, Brazil. The system was designed to serve 100 PE (-1 m2/PE). The first filter was planted with cattail (Typha latifolia), the second with Tifton-85 (Cynodon spp.) and the third was maintained without plants (control unit). NaCl tracer tests were conducted to determine the residence time distribution. The tests were done with water when the system was unused (clean media) and also after an 11-month operation period with wastewater (used media), using two different dosing regimes (lower and higher frequency). Results showed a strong tendency towards the hydraulic completely mixed regime. A great dispersion in the units and the presence of short circuiting and dead zones were observed. The unsaturated condition in a large volume of the filter, even during the draining stage, was confirmed for the three units. The dosing regime, the resting period duration, the age of the filter and the presence of plants were found to influence the hydraulic processes in the units.
Assuntos
Purificação da Água/métodos , Áreas AlagadasRESUMO
A patient with left ventricular power failure after aortocoronary saphenous vein bypass was successfully managed by intraaortic dual-chambered balloon counterpulsation through the ascending aorta. This insertion route reverses the orientation of the spherical distal chamber, which inflates early in diastole and partially occludes the aorta. This position achieved an effective augmentation pressure during left ventricular diastole and reduced arterial end-diastolic pressure considerably. The technique of insertion and events at operation and postoperatively are discussed.