Made available in DSpace on 2014-12-17T15:01:43Z (GMT). No. of bitstreams: 1 LibertalamarBS.pdf: 1245835 bytes, checksum: e50b7694a4b730a50be93e5d2ce30412 (MD5) Previous issue date: 2007-06-01 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Stabilization ponds are an effective sewage treatment alternative for the climatic conditions prevailing in Brazil. In the present work, a primary facultative pond was studied, in the city of Natal, Rio Grande do Norte, Northeast Brazil. The aim of this study was to evaluate the sedimentation dynamics in the facultative pond. The pond was divided in three section or zones along its length starting from the inlet end namely A1, A2 and A3. The research was accomplished in three phases. In the first the mapping of the sludge layer was done, sludge core samples were also collected for analysis for total, fixed and volatile solids and the depth of the sludge layer was determined using a portable echo sounder. In the second solids sedimentation rates were measured using traps placed in the inlet and outlet zones and in the third phase resuspension sludge was evaluate using a tracer. The amount accumulated sludge since the start operation was 13.583 m3. The sedimentation constant averages changed between 0.93 to 2.94 and 3.90 to 5.80 for the depths of 0.5 and 1.0 m respectively. The relationship between volatile and fixed solids (SV/SF) increased along the pond. The removal efficiencies were 52.12%, 36.09%, and 37.50% for BOD, COD and SS, respectively. The sludge accumulation model proposed had a good adjustment with 0.17 m3/hab.year rate. The results presented here demonstrated that the wind had a direct influence on the sedimentation of solids in this pond affecting the efficiency and sludge accumulation / As lagoas de estabiliza??o s?o alternativas vi?veis para o tratamento de esgoto no Brasil, pelas condi??es clim?ticas. Neste trabalho foi estudada uma lagoa facultativa prim?ria, na cidade do Natal, estado do Rio Grande do Norte. O objetivo do estudo foi avaliar a din?mica de sedimenta??o. A lagoa foi dividida em tr?s se??es ao longo de sua extens?o denominadas A1, A2 e A3 e o estudo foi dividido em tr?s fases. Na primeira foram feitos o mapeamento da camada de lodo, caracteriza??o do lodo e a determina??o da espessura por batimetria. Na segunda, a taxa de sedimenta??o de s?lidos foi determinada usando armadilhas suspensas verticalmente na coluna de ?gua a 50 cm e 100 cm de profundidade. Na terceira fase a re-suspens?o dos s?lidos foi verificada com tra?ador em 10% do volume da lagoa. Amostras de afluente e efluente foram coletadas para an?lise de pH, DBO, DQO e s?lidos suspensos. O volume de lodo acumulado desde o come?o da opera??o do sistema, foi de 13.583 m3. As constantes m?dias de sedimenta??o variaram entre 0,93 a 2,94 e 3,90 a 5,80 para as profundidades de 0,5 e 1 m, respectivamente. A rela??o entre s?lidos vol?teis e fixos (SV/SF) na camada de lodo aumentou ao longo da lagoa. As efici?ncias de remo??o foram de 52,09 %, 36,12%, 37,50 % para DBO, DQO e SST, respectivamente. A taxa de ac?mulo de lodo foi estimada em 0,17 m3. hab-1.ano-1 e o modelo matem?tico proposto conseguiu estimar de forma satisfat?ria o volume de lodo depositado. Os resultados mostram que a dire??o e a velocidade do vento tem uma influ?ncia direta na sedimenta??o dos s?lidos nesta lagoa afetando a efici?ncia e o ac?mulo de lodo

No / Sedimentation of non-homogeneous systems is the typical phenomenon indicating the physical instability as a key measure to the quality control of the preparation products. Currently, the determination methods for the sedimentation of non-homogeneous preparations are based on manual measurement or semi-quantitative observation, lacking of either automation or quantitative dynamic analysis. The purpose of this research was to realize automatic and quantitative monitoring of the sedimentation dynamics for non-homogenous systems as suspension, emulsions at laboratory level. Non-contact measurement method has been established to determine the sedimentation behaviors in a standard quartz tube for sedimentation, with internal diameter and height 23 mm and 215 mm, respectively, with controlled temperature and light intensity. As high performance camera has been equipped, the sedimentation images with high spatial and temporal resolution could be acquired, which can continuously capture sedimentation images with the resolution of 2048 x 2048 pixel at a maximum rate of 60 slides/s. All the pictures were processed to extract the luminance matrix top-down along the fixed vertical midline of each picture, which implied sedimentation characteristics of the system at the moment the picture was taken. Combining all the luminance matrixes along vertical middle lines of the pictures, a time-luminance matrix profile was obtained. Digital image processing techniques were used to eliminate interference and establish a three-dimensional surface model of the sedimentation dynamics. Then, the derivative mutation algorithm has been developed for the intelligent identification of sedimentation interface with threshold optimization so as to quantitatively analyze the sedimentation dynamics with visualization. The sedimentation curve and sedimentation dynamic equation of the non-homogeneous system were finally outputted by numerical fitting. The methodology was validated for great significance in determinations of small volume samples, parallel control multiple batches, and long period of time automatic measurement. (C) 2015 Elsevier B.V. All rights reserved.